ANALYSIS AND OPTIMIZATION OF

SOLAR THERMAL PLANT WITH

24×7 THERMAL STORAGE

A thesis submitted for the degree of

Doctor of Philosophy
In
Mechanical Engineering

Submitted by
Anil Kumar

Supervisor Co-Supervisor Co-Supervisor

Prof. V K Sethi Prof. Suresh Kumar Soni Prof. Sachin Tiwari

Faculty of Engineering and Technology

RAM KRISHNA DHARMARTH FOUNDATION
UNIVERSITY, BHOPAL
2020
 DECLARATION BY THE CANDIDATE

DECLARATION

I declare that the thesis entitled “ANALYSIS AND OPTIMIZATION OF SOLAR

THERMAL PLANT WITH 24×7 THERMAL STORAGE” is my own work
conducted under the supervision of Prof. Dr. V K Sethi and co-supervision of
Dr. Suresh Kumar Soni, S. V. Polytechnic College, Bhopal and Prof. Sachin
Tiwari, LNCT, Bhopal approved by Research Degree Committee. I have put in more
than 240 days of attendance with supervisor at the centre.

I further declare that to the best of my knowledge, the thesis does not contain any part
of any work, which has been submitted for the award of any degree either in this
University or in any other University without proper citation. It is also declared that
the content in this thesis is within permissible limits with reference to plagiarism and
is in accordance with UGC (Promotion of Academic Integrity and Prevention of
Plagiarism in Higher Educational Institutions) Regulations, 2018. If at any stage it is
found that I have made a false declaration, appropriate action may be taken against
me.

Signature of Candidate
(Anil Kumar)

Date:
Place:

i
 CERTIFICATE

This is to certify that the work entitled “ANALYSIS AND OPTIMIZATION OF

SOLAR THERMAL PLANT WITH 24×7 THERMAL STORAGE” is a piece of
research work done by Shri Anil Kumar under my guidance and supervision for the
degree of Doctor of Philosophy of Ram Krishna Dharmarth Foundation
University, Bhopal (M.P.) India. I certify that the candidate has put-in an attendance
of more than 240 days with me.

To the best of my knowledge and belief the thesis:

(1) Embodies the work of the candidate himself/herself:

(2) Has duly been completed:
(3) Fulfil the requirement of the ordinance relating to the Ph.D. degree of the
university: and
(4) Is up to the standard both in respect of contents and language for being
referred to the examiner.

Signature of Co- Supervisor Signature of Co- Supervisor

Date: Date:

Signature of Supervisor
Date:

ii
 FORWARDING LETTER OF HEAD OF THE INSTITUTE

The Ph.D thesis entitled “ANALYSIS AND OPTIMIZATION OF SOLAR

THERMAL PLANT WITH 24*7 THERMAL STORAGE” submitted by
Shri Anil Kumar is forwarded to the University in three copies. The candidate has
paid the necessary fees and there are no dues outstanding against him/her.

Name: Seal: ………………..

Signature of Supervisor (s)

Date:

Place:

Date: ………………………………………
Signature of Head of the Institute
Where the candidate was registered for
Ph.D degree

iii
+

ACKOWLEDGEMENT

The journey of thousand miles begins with a single step. It’s a lovely, quite gentle-
trail from other thing a part. I only meet when travelling there the folks. This is the
right time to thank all those people, who were always there with me, for the past years
during my research work. Completion of this doctoral thesis was possible with the
support of several people. I would like to express my sincere gratitude to all of them.

Firstly for God, Thank you for the gift of life, for letting me be me, for all that I can
know by words and all that I can see, for all the joy that comes to me and all the joy I
bring, for all the loved ones I can touch, who love and wish me well, for all the beauty
of world, Even fresh and new, I don’t know whom else I can thank, and so I am
thanking you.

I express my deep gratitude to my Ph. D. supervisors Prof. V K Sethi, Prof. Suresh

Kumar Soni and Prof. Sachin Tiwari for their precious direction and continuous
support during the period of this research work. They have devoted their valuable
time in facilitating the formulation of research problem.

I would like to express my profound gratitude & indebtedness to my esteemed

respected Dr. M. L. Kori, Director Research, RKDF University, Bhopal for his
valuable guidance, scholarly inputs and consistent encouragement that I received
throughout my research work.

I also extend my gratitude to them. I am thankful to Prof. Sudesh K Sohani Hon’ble

Vice Chancellor, RKDF University, Dr. B N Singh DG (Management), Dr. Ravi S
Pippal Dean (FOE&T) and Dr. Narendra Kumar Lariya Registrar RKDF
University for providing me the necessary guidance and Advice from time to time.

At every step of this venture, my beloved my father Mr. Bengali Babu and
mother Mrs. Ramesho Devi, with all family members who shared with me all the
moments of different colors with immense love.

iv
 I appreciate younger brother Mr. Arun Kumar and his wife Mrs. Rupali. I
also appreciate to lovely my daughter Ananya Jayant, Aaratrika Janant for abiding
my ignorance and the patience showed during my thesis writing. I also very much
thankful to my dear Mr. Prashant Mishra for his valuable support.

I loving and deepest gratitude to my dearest wife Mrs. Anjali Bhasker, for his
unconditional support, help, care, love & understanding in my whole research work.
Without his help, I would not have been able to complete much of what I have done
and become who I am.

Anil Kumar

v
 ABSTRACT

Rapidly rising demand of energy, fast depleting and limited stock of fossil fuels, their
serious environmental issues compel to shift towards to more use of renewable energy
sources. There are some critical issues while using renewable energy sources like
reliability, quality, etc. Energy storage systems have the capability to solve the
problems up to some extent towards smooth and continuous energy supply.

Due to rapid growth in infrastructure sector (i.e. communication, transport, road and
rail networks, etc.), demand of energy is rising enormously and more than 20-30%
demand is satisfied by non- conventional energy sources. Renewable or non-
conventional energy sources are essential for the sustainable development, have many
advantages over conventional energy sources like availability, environment friendly,
etc. But the most important difficulty is the uneven generation of energy. Therefore,
trustworthy and affordable energy storage system becomes a prerequisite for using
renewable energy. Energy storage systems play pivotal role towards smooth and
continuous energy supply. Energy storage system holds the generated energy for a
short time and supplied it according to need. Therefore, energy storage system is the
most capable technology to meet the rising demand of energy. A device that
accumulates energy is sometimes termed as an accumulator. There are various energy
storage systems. Paper presents brief overview of various energy storage systems.

Many researches come on the conclusion that renewable energy sources are the only
option for sustainable development and appropriate energy storage systems are the
prerequisite. They have feature to store the energy and then release as and when
required.

vi
 CONTENTS

DECLARATION BY CANDIDATE I
CERTIFICATE OF THE SUPERVISORS II
FORWARDING LETTER OF HEAD OF INSTITUTE III
ACKNOWLEDGEMENT IV-V
ABSTRACT VI
CONTENTS VII-VIII
LIST OF FIGURES IX-X
LIST OF TABLES XI
SYMBOLS AND ABBREVIATIONS XII-XIII

CHAPTER-1 INTRODUCTION 1-21

1.0 General 1
1.1 Energy Scenario 2
1.2 Need of Work 2
1.3 Energy Sources 3
1.4 Energy storage Systems 8
1.5 Objectives of Research work 19
1.6 Experimental set ups 19
1.7 Outline of the Thesis 21

CHAPTER-2 LITERATURE REVIEW 22-34

2.0 General 22
2.1 Power Installed Capacity 22
2.2 Energy Storage Systems 23
2.2.1 Battery Storage System with Solar Photovoltaic 23
2.2.2 Solar Storage System with Solar Thermal 24
2.3 Thermal Storage Systems 26
2.4 Research Gap 34

CHAPTER-3 EXPERIMENTAL SET UPS 35-53

3.0 General 35
3.1 Description of Experimental Set Ups 35

vii
 3.1.1 Experiment Set Up-I 35
3.1.2 Experiment Set Up-II 45

CHAPTER-4 EXPERIMENTAL DATA ANALYSIS, RESULTS 54-92

& DISCUSSIONS
4.0 General 54
4.1 Performance of Reflector Round the year (Exp. Set Up-I) 54
4.1.1 Detailed Project Report 55
4.1.2 Detailed analysis of report 57
4.1.3 Simulation results 61
4.1.4 Testing works carried out 62
4.1.5 Work carried out 65
4.1.6 Quantity of steam to Turbine 68
4.1.7 P&ID’s of various sub systems 69
4.1.8 Operating Parameters for Turbine 72
4.2 Operation Parameters and Results 73
4.2.1 Solar & Thermal Benefits Accured 74
4.2.2 Manpower trained under the project 79
4.2.3 Objectives of the CST Centre 80
4.2.4 Scope of Activities 80
4.3 Thermal Behaviour of Receiver 83
4.4 Performance Report 86

CHAPTER-5 CONCLUSIONS AND FUTURE SCOPE 93-95

5.0 General 93
5.1 Conclusions from Performance of 1 MWe 93
5.2 Conclusions from Performance of 1 kWe 94
5.3 Comparative Analysis of Solid Thermal Storage Systems 94
5.4 Future Scope 95
REFERENCES 96-100
LIST OF PUBLICATIONS 101
PLAGIARISM REPORT

viii
 LIST OF FIGURES

Figure No. Title Page No.

1.1 Classification of primary energy sources 3
1.2 Secondary energy sources 4
1.3 Classification of solar energy 4
1.4 Classification of CSP systems 5
1.5 Parabolic trough collector 6
1.6 Linear Fresnel reflector 7
1.7 Solar tower 7
1.8 PDC system 7
1.9 Energy storage systems 9
1.10 Flywheel energy storage system 10
1.11 Compressed air energy storage 11
1.12 Pumped storage 12
1.13 Battery 13
1.14 Hydrogen fuel cell 14
1.15 Earth air heat exchanger 15
1.16 Superconducting magnet energy storage 16
1.17 Molten salt storage system 17
1.18 Stone storage system 18
1.19 Approach for the research work 20
3.1(a) Parabolic solar reflector 36
3.1 (b) Supporting Stand 37
3.1 (c) Rotating Wheel 38
3.1 (d) Parabolic Outer Frame 39
3.2 Flexible parabola 43
3.3 Various actuators 43
3.4 (a) Receiver coil drawing (b) Block drawing 44
3.5 Size and photo mixed alkali halide compounds doped 48
with metallic impurities
3.6 Cast-iron core crucible design 48
3.7 Schematic of experimental set up 49
3.8 Installation of the solar thermal storage and solar tracker 50
unit

ix
3.9 Solar thermal storage with solar tracker unit 51
3.10 Tracking motor 52
3.11 Tracking rope & Chain 53
4.1 Changes in aperture area of reflector 54
4.2 Measuring System 1 and 2 for the receiver and solar 56
radiation
4.3 Results for the temperature distribution 58
4.4 Heat Loss and Radiation for different Receivers in a 59
module
4.5 Receiver Charging-Discharging 63
4.6 Receiver with grooving’ 64
4.7 India One solar plant 65
4.8 P&ID logic implemented in the control logic 68
4.9 P & ID’s of various sub systems 71
4.10 Operation parameters and Results 73
4.11 Variation in the aperture area 81
4.12 Ave. DNI of the location for the year 2016 82
4.13 Thermal output of 60 SQM reflectors for the year 2016 82
4.14 Thermal behavior of the Receiver without front glass 83
4.15 Thermal behavior of the cover at receiver opening front 84
glass
4.16 Thermal behavior of the Receiver with front glass 85
covering at the receiver opening and with water flow
through the heat transfer coil
4.17 Filling of salt at core of receiver 88
4.18 Focus of lens at tip of receiver 89
4.19 Temperature (max.) recorded during field test 90
4.20 Salt heating and cooling cycle during lab test 91
4.21 Steam output of system 92
5.1 Steam generation through solar thermal storage and apply 95
in CCS system

x
 LIST OF TABLES

Table No. Title Page No.

2.1 Total Power Installed Capacity of India (As on 22
30.09.2019)
2.2 Costing of 1 MW Solar PV (24x7) 23
2.3 Cost analysis of 1 MWh solar power 24x7 energy storage 24
2.4 Different climate zone of various part of India, suitable 228
technologies & thermal storage systems
3.1 Equipment list used in the experimental set up 46
4.1 Simulation results 62
4.2 Operating data and limit value (Turbine1) 72

xi
 SYMBOLS AND ABBREVIATIONS
Symbols

kW : kilo Watts

kWh : kilo Watt hours

TR : Tons of Refrigeration

Kg : kilograms

$ : Dollars

Rs : Rupees

H : Hours

m : Meter

L : Length (m)

W : Width (m)

H : Height (m)

T : Temperature (o C)

Tin : Temperature at entry of pipe (o C)

Texit : Temperature at exit of pipe (o C)

MW : Mega Watt

GW : Giga Watt

xii
 ABBREVIATIONS

CO2-e : Carbon Dioxide-Equivalent

CER : Certified Emission Reduction

CFD : Computational Fluid Dynamics

CSP : Concentrated Solar Power

CL-CSP : Cross Linear Concentrated Solar Power

DNI : Direct Normal Irradiance

EAHE : Earth Air Heat Exchanger

GDP : Gross Domestic Product

GHGs : Green House Gases

HTF : Heat Transfer Fluids

IMD : India Metrological Department

IPCC : Intergovernmental Panel on Climate Change IRR :

Internal Rate of Return

LFR : Linear Fresnel Reflector

MS : Molten Salt

NPV : Net Present Value

PBP : Pay Back Period

PCM : Phase Change Material

PDC : Parabolic Dish Collector

PV : Photo Voltaic

PSR : Parabolic Solar Reflector

PTC : Parabolic Trough Collector

SARA : Solar Radiation Resource assessment

ST : Solar Tower

TES : Thermal Energy Storage

xiii
 CHAPTER-1
INTRODUCTION
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1. GENERAL

In current state of affairs, requirement of energy is rising exponentially in every

sectors i.e. manufacturing, infrastructure etc. Infrastructure sector (i.e. hospitals,

restaurants, lodges, shopping complexes, educational big schools, colleges, corporate

offices, multiuse etc.) is developing very speedy due to growing population, need of

high comfort level due to advancement in people’s living standard, energy

consumption is increasing rapidly. Heating/cooling requirement of the building only

consumes 30-34% of the total global energy consumption. They are resulting key

problems in a variety are like pollution control, change in climatic conditions, global

warming, ozone layer depletion etc. that creates many health issues. Right now,

energy management and security are the globe priority topics. The Intergovernmental

Panel on Climate Change (IPCC) has accepted that Green House Gases (GHGs) are

the first and foremost responsible for the various environmental issues like climate

change and global warming.

Large numbers of researchers suggest that promoting more use of renewable energy

would be the revolutionary way to control GHGs emissions. There are various

renewable options available, choice of them must be according to satisfying various

criteria i.e. techno-economic, environmental issues, geographical conditions, required

energy quality, etc.

Energy intensity and its 24×7 availability have become the main relative measures of

countries. Energy use to Gross Domestic Product (GDP) is known as energy intensity.

It’s value usually higher for developing compare to the already developed countries.

Higher value demonstrates huge energy dependence. India consumes approximately

6% of world’s primary energy.

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1.1 ENERGY SCENARIO

In India, 1363 MW was the total installed capacity in 1947. Then reached to 314.64

GW in 2017. During 2012-17 in the 12 th Five Year, 88,425 MW target was set.

Majority part means 50,000 MW was based on coal fired thermal power plant.

Presently Major portion of power generation is based on coal, oil, gas, nuclear (70%),

then hydro (17%) and renewable (13%). But due the limited stock and its

environmental issues compel to move towards alternative source of energy (i.e.

renewable-solar, wind, biomass, geothermal, ocean, hydrogen, etc.). The IPCC report

(June 2011) on the climate change by 2050 share of renewable energy in global

energy mix could arrive up to 77%.In India, in the 12 th Five Year Plan (2012-17),

target of 29,800 MW power capacity (i.e. renewable energy share more than 12% in

terms of installed capacity) has been set from renewable energy sources. Currently

energy consumption rate in India has reached to just double compare to year 2000.

There are mainly five major energy consuming fields i.e. industries, agriculture,

transport, communication, buildings (i.e. commercial and residential).

1.2 NEED OF WORK

Major difficulties of 21stcentury are:

 Climate change has come out as a biggest problem

 Global warming due to GHGs

 GHG emissions due to use of fossil fuels

 Reducing balance of fossil fuels

 Availability of 24×7 electricity for all

 Variation in energy demand i.e. during shift change, night peak hours, etc.

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To overcome from above mentioned problems, it is essential to encourage:-

 Effective energy management to conserve and balance demand & supply

 Optimal use of natural energy resources

 Discourage the use of fossil fuel based energy

 Acceptance of various new hybrid technologies in which partly/fully energy is

shared by renewable

 Promote new hybrid technologies coupled with energy storage

1.3 ENERGY SOURCES

It can be classified as primary and secondary energy sources. Primary energy sources

are normally categorized as renewable and non-renewable on the basis of their

depleting characteristics, as shown in Fig. 1.1. Renewable energy derived from

natural resources and they are automatically replenished. It is also known as clean

energy sources.

Primary energy
sources
Inexhaustible (Solar, wind, h
Non- Renewable
renewable
Exhaustible
(Fossil fules
i.e. oil,Fig.
gas,1.1 Classification of primary energy sources

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Secondary energy sources are derived from transformation of primary energy sources

i.e. heat and electricity, as shown in Fig. 1.2.

C
onver t

Prima Secondary energy sources

Heat &
ry Electricit
energ y, etc.
Fig. 1.2 Secondary energy sources

Renewable energy sources are inexhaustible but as per Indian climatic conditions

solar energy is most suitable energy source, shown as Fig. 1.3.

Solar energy
Directly converts into heat

Solar PV Solar thermal

DirectlyFig. 1.3 Classification of solar energy

converts into
electricity
Solar Photovoltaic (PV) and solar thermal both are efficient, getting popularity all

over the globe. Selection of them is depends on utility, suitability. For energy storage

and 24×7 energy supply solar thermal technology is getting more popularity than

solar PV technology. Solar thermal technology is also acknowledged as Concentrating

Solar Power (CSP).

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1. CSP systems

CSP systems could be cost-effectively feasible at minimum 1600-1800 kWh/m 2/year

Direct Normal Irradiance (DNI) by utilizing novel technologies, substances,

economies of scale and supporting renewable policies, etc [1,2]. CSP systems have a

range of prime objectives. These are to work environmentally safe, to diminish

primary cost and ground area, to increase long-term system trustworthiness, to make

possible ease in service and maintenance. Sequestration of one ton of Carbon

Dioxide-Equivalent (CO2-e) equivalent to one CER unit. CSP technologies can be

categorized as line and point focus, shown in Fig. 1.4 [3].

CSP

. Line focusing .Point focusing

. Parabolic . Solar
Fig. 1.4 Classification of CSP tower
systems
trough . Dish system

Parabolic trough comprises a parabolic linear reflector. It reflects or focuses sun

rays/radiations towards the receiver, shown in Fig. 1.5. Thermal heat is absorbed by

working fluid (i.e. molten salt, etc.), that is filled in the receiver’s tube. Reflector has

a tracking system to track the maximum sun radiations. Working fluid achieves the

temperature 150-350o C. Weight of parabolic linear reflector is higher due to joint

less design, therefore tracking systems consume enormous auxiliary power [4].

To conquer this trouble, several curved mirrors are positioned rather than a single

parabolic reflector that is known as Linear Fresnel Reflector (LFR), shown as Fig.

1.6. LFR is less proficient compared to parabolic trough, due to problem in tracking

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its multiple curved mirrors. As a result of fixed position of curved mirrors, at the time

of sunrise and afternoon cosine losses also arises in addition to longitudinal cosine

losses as compared to parabolic trough. Still having these drawbacks, it is trouble-

free, less maintenance and generation cost per kWh is lower than the parabolic trough

[5, 6, and 7].

Receiver’s position is kept at a higher position to reduce it's shadow effect. In

contrast, due to higher height and longer path, losses also increase.

Solar tower is another technology, as shown in Fig. 1.7 [8]. Array of heliostats tracks

sun in double-axis. The working fluid is gets heated in between 500-1000 o C. Main

constraint of this technology is the size, design of the tower.

Parabolic Dish Collector (PDC) system concentrates sun radiations towards receiver

similar to parabolic trough but focused on a single point, shown as Fig. 1.8. Working

fluid gets heated up to 750o C. It is more efficient compared to others but suitable for

small capacity applications only.

solar radiation Receive Reflector

r

Aperture width

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[Type text]

Fig. 1.5 Parabolic trough collector

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[Type text]

Receiver tube

Mirrors

Fig. 1.6 Linear fresnel reflector

Central receiver

Heliostats
Fig. 1.7 Solar tower

Concentrator Receiver

Fig. 1.8 PDC system

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1.4 ENERGY STORAGE SYSTEMS (ESS)

Rapidly rising demand of energy, fast depleting and limited stock of fossil fuels, their

serious environmental issues compel to shift towards to more use of renewable energy

sources. There are some critical issues while using renewable energy sources like

reliability, quality, etc. Energy storage systems have the capability to solve the

problems up to some extent towards smooth and continuous energy supply.

Due to rapid growth in infrastructure sector (i.e. communication, transport, road and

rail networks, etc.), demand of energy is rising enormously and more than 20-30%

demand is satisfied by non-conventional energy sources [9]. Renewable or non-

conventional energy sources are essential for the sustainable development, have many

advantages over conventional energy sources like availability, environment friendly,

etc. But the most important difficulty is the uneven generation of energy. Therefore,

trustworthy and affordable energy storage system becomes a prerequisite for using

renewable energy [10-12]. Energy storage systems play pivotal role towards smooth

and continuous energy supply. Energy storage system holds the generated energy for

a short time and supplied it according to need. Therefore, energy storage system is the

most capable technology to meet the rising demand of energy. A device that

accumulates energy is sometimes termed as an accumulator. There are various energy

storage systems. Paper presents brief overview of various energy storage systems.

Many researches come on the conclusion that renewable energy sources are the only

option for sustainable development and appropriate energy storage systems are the

prerequisite. They have feature to store the energy and then release as and when

required. Classification of energy storage systems are shown as Fig. 1.9.

[Type text]
 [Type text]

Energy Storage Technologies

Mechanical Electrochemical
Thermal Electrical

1.Sensible-
1.Pumped Hydro Energy Storage (PHES) (i) Liquid-Molten Salt, Chilled Water (ii) Solid- hellide, cast iron
1.Super Capacitors

Compressed Air Energy Storage 2.Latent- ice Storage, Phase Change materials
2.Superconducting Magnetic Energy Storage(SMES)
-Earth Air heat Exchanger
-Stone Storage

Flywhewel Energy Storage

3.Thermochemical Storage

Chemical (Hydrogen electrochemical)

1. Power-to -
Power
(Fuel Cells, etc)

2. Power-to-Gas

[Type text]
 3.Flow Batteries (ZnBr, Vn Redox)

[Type text]

4.Sodium Batteries
(NaS, NaNiCl2)

5.Zinc Batteries- Zn Air, ZnMnO2

Fig. 1.9 Energy storage systems (Source: indiasmartgrid.org)

Some ESSs i.e. flywheel energy storage, compressed air energy storage, pumped

storage, batteries, regenerative fuel cell storage, superconducting magnet energy

storage are explained here.

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A. FLYWHEEL ENERGY STORAGE SYSTEM

Flywheel energy storage systems store energy mechanically in the flywheel rotor by

rotating the rotor. Afterward generator is employed to convert mechanical energy to

electrical, as shown in Fig. 1.10. It is efficient and used for various applications. It is

preferred due to compactness, light in weight and high energy capacity. But due to

limited amount of charge/discharge cycle characteristic, it is not cost-effective.

B. COMPRESSED AIR ENERGY STORAGE

It is also known as stone storage system. Air is compressed to absorb and store heat

energy after that released to utilized to generate steam and electricity. Conceptual

diagram is shown as Fig. 1.11. It is getting popularity due to quick start-up, able to

integrate with other energy sources but requires geological structure reliance [13].

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C. PUMPED STORAGE

In pumped storage system, water is pumped and stored at height during off-peak

periods then utilized to generate electricity to meet the peak demand of electricity for

our country.

Hydro power plants store electricity in Megawatts (MW) or Gigawatts (GW). It has

many advantages i.e. fast start-up, reliable but requires large area and cost.

D. BATTERY

Basic construction, working principle, functions of battery is very familiar .Portable

batteries are well accepted in many small storage applications like transport sector,

utilities, etc. But it has some drawbacks like high cost, short life and regular

maintenance.

E. SUPERCONDUCTING MAGNET ENERGY STORAGE

This is an advanced energy storage system. It stores energy in the magnetic field

within magnets that is developed by flow of direct current in a superconducting coil,

and then releases it within fraction of cycle, as shown in Fig.1.16.

[Type text]
[Type text]

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[Type text]

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[Type text]

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F. MOLTEN SALT

Molten salt storage systems are the established commercially available concept for

solar thermal power plants. Due to their low vapor pressure and comparatively high

thermal stability, molten salts are preferred as the heat transfer fluid and storage

medium. However, due to pricing pressure, the development of alternative, more cost-

effective concepts is an important step in making thermal energy storage more

competitive for industrial processes and solar thermal applications [17, 18]. A closer

look at the capital cost distribution of two-tank storage systems, reveals that indirect

systems with a maximum operating temperature of 400 °C have differing heat transfer

fluids (HTF) and storage media. For those systems, the molten salt storage media

(about 35% of the direct capital costs) and the storage tanks (about 24% of the direct

capital costs) are the main bearers of cost. For direct systems with operating

temperatures up to 560 °C, using molten salt as the HTF and the storage media, the

capital cost ratios are 34 % for the storage media and 31 % for the storage tank,

respectively [19], as shown in Fig. 1.17.

Fig. 1.17 Molten salt storage system

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G. STONE STORAGE

In this type of energy storage medium is pebbles that has significantly higher thermal

conductivity than normal concrete. Although the recipe of this material is quite

complex the main component is quartzite, natural geo-material readily available in

many parts of the world. Further, heat is transported in and out of the storage by way

of a heat transfer fluid (HTF) which flows through steel pipe heat exchangers that are

cast into concrete storage elements, as shown in Fig. 1.18. These elements are

specially designed to deal with thermal deformations and stressing [20, 21]. Stone

storage may be a good technology for CL-CSP system.

Fig. 1.18 Stone storage system

It can be concluded from comparative study of various energy storage systems that for

the need of large scale energy storage underground thermal, pumped hydro and

compressed air energy storage systems are suitable. Superconductors are able to store

energy with negligible losses. Fuel cells are a viable alternative to petrol engines due

to their high efficiency. Flywheels have a narrow range and suitable for small scale

operations. Molten salt and stone storage systems are gaining more acceptability for

solar thermal power plants [22-32].

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1.5 OBJECTIVES OF THE RESEARCH WORK

According to current rising trend in energy demand, reducing balance stock of fossil

fuels and its impact on environment and health, it is urgent to switch over to

alternative source of energy i.e. renewable with efficient storage systems.

The objectives of the present work are to develop methodology for hybridizing the

solar thermal (i.e. CSP) with thermal storage to 24×7 uninterrupted energy supply.

Objective-I

 Experimentally performance analysis of 1 MWe (3.5 MW) solar thermal power

plant with 16 hours thermal storage for continuous operation established at Mount

Abu, Rajasthan.

 Experimentally performance analysis of 3.5 kWe (1 kWh) solar thermal power

plant with 24 hours thermal storage for continuous operation established at

Bhopal, Madhya Pradesh.

Objective-II

 To compare the performance of above mentioned both solar thermal power

plant coupled with storage system for the Indian climate conditions.

1.6 EXPERIMENTAL SET UPS

For controlling pollution level and fulfilling energy demand 24×7, hybrid

(combination of CSP with thermal storage) system is appropriate. Approach for the

research work is shown in Fig. 1.19. In research two experimental set ups are

developed. They are as follows:-

Experimental set up -01

- Mount Abu

Experimental set up -02

- Bhopal

[Type text]
[Type text]

CSP coupled with energy storage

Solar Thermal (CSP) system Energy storage system

Hybrid efficient solar thermal coupled with energy storage system 24×7

Experimental set up-I (Established at Mount

Experimental
Abu, Rajasthan)
set up-II (Established at Bhopal, M

Compare performances
of both the experimental set ups for different
seasons

Out come of the research

Fig. Approach for the research work

[Type text]
[Type text]

1.7 OUTLINE OF THE THESIS

This thesis has five chapters as given below:

In Chapter 1, Need of Energy Storage 24×7, overview on energy scenario, solar

energy and approach of research work is explained.

Literature Reviews on Concentrated Solar Power (CSP) systems, energy storage

systems are presented in Chapter 2. The gaps noticed in the literature review are

brought out.

Experimental set ups for optimal operation of energy systems is presented in

Chapter 3.

Experimental data analysis, results and discussions of energy storage systems

represented in Chapter 4.

In Chapter 5, Conclusions are drawn from both experimental set ups. Further scope of

work is mentioned. The references and publications of research papers are provided

in Appendices.

[Type text]
 CHAPTER-2
LITERATURE REVIEW
2. GENERAL

Literature on the basic concept of solar thermal systems and energy storage systems,

their classifications, performances has been reviewed. It comprises the performances

fetches out their merits and demerits. Therefore, literature review is presented under

following heads:

- Power installed capacity of India

- Battery storage systems

- Thermal storage systems

2. 1 POWER INSTALLED CAPACITY

Worldwide energy demand is growing exponentially. Simultaneously environmental

issues and reducing balance of fossil fuels alarm and force us to switch over towards

alternative options with 24x7 energy storage. Power installed capacity of India is

presented in Table 2.1.

Table 2.1. Total Power Installed Capacity of India (As on 30.09.2019)

Fuel MW % Share
Total Thermal 2,27,644 63.2
Coal 1,96,895 54.2
Lignite 6,260 1.7
Gas 24,937 6.9
Diesel 510 0.1
Hydro(Renewable) 45,399 12.6
Nuclear 6,780 1.9
RES (MNRE) 82,589 22.7
Total 3,63,370 100
2.2 ENERGY STORAGE SYSTEMS

There are various options for 24x7 energy storage (i.e. batteries, solar thermal etc.)

coupled with alternative energy sources.

2.2.1 BATTERY STORAGE SYSTEM WITH SOLAR PHOTOVOLTIC

Tremendous literatures are available for battery storage systems. Cost analysis of 1

MW solar power (i.e. Solar PV) 24x7 energy storage with lead acid batteries is

presented in Table 2.2.

Table 2.2. Costing of 1 MW Solar PV (24x7)

Load required: 24 MWh-AC

Inverter efficiency @ avg 95% 24/0.95 = 25.26 MWh

Battery @80% 25.26/0.80 = 31.57 MWh

Charge Controller @ 96% 31.57/0.96 = 32.89 MWh

Array thermal loss @ 80% 32.89/0.80 = 41.11 MWh

Radiation available 5 KWh for 5.5 hrs

PV array Capacity required 41.11 MWh/5.5 h = 7.47 MWp

Cost of PV @ 4 crore per MW 7.47 x 4 = 29.89 crores

Battery cost for uninterrupted power 30 MWh approx.

supply and best quality power output

Cost of lead acid battery @ Rs. 7000 per 30,000 x 7000 = 21 crores for period of
KWh for period of 5 years 5 years, Therefore for period of 20
years, we have to replace the battery 5
times, so total cost for battery will be
around 21 x 4= Rs. 84 crores

Cost of Li-ion battery @ Rs 14000 per 30,000 x 14000 = 42 crores for period of
KWh for period of 10 years 10 years, Therefore for period of 20
years, we have to replace the battery 5
times, so total cost for battery will be
around 42 x 2= Rs. 84 crores

Hence total cost of 1 MW PV based lead acid battery operated power plant: 29.89 +
84 = 113.89 crores say Rs. 114 crores for stabilized uninterrupted quality power.

So 1 MWh produces 1000 unit every 24 x 1000 = 24,000 unit daily

hour, for 24 hrs

Cost of unit sale @ Rs. 5/ unit 24,000 x 5 = 1,20,000

Cost of diesel plant is around Rs. 18 per 24,000 x 18 = 4,32,000

unit

2.2.2 THERMAL STORAGE SYSTEM WITH SOLAR THERMAL

For MW scale solar thermal power plant based on parabolic trough collector (PTC)

and molten salt as thermal storage, the following cost analysis of 1 MW solar power

(i.e. Solar thermal) 24x7 energy storage is presented in Table 2.3.

Table 2.3. Cost analysis of 1 MWh solar power 24x7 energy storage

Ero trough + schott vacuum tube cost Rs ~ 30,000 per sq.m

1 MW x 24 18% turbine 24 MWh electrical

Thermal anticipating loss 10% 110/18 = 6.1 times

Megawatt thermal capacity 24 x 6.1 = 146 MWH or say 150 MWH

Average DNI 4.5 KWh/m2

Efficiency of trough 60% 4.5 x 0.6 = 2.7 Kwh/m2 of PTC

Requirements 150 MWH = 150 x 1000

 = 150000 Kwh/2.7

= 55,555 m2 of PTC x 30,000

= 16.666 crores

BOP turbine Island

Storage-molten salt KNO3 + NaNO3 ~ Rs

120/Kg

150 MWH x 0.7 ~ 105 MWH thermal

storage

= 105 x 1000 x 50 x70

= 36.5 crores storage cost

Total cost 16 cr + 36 cr = 60 crores

Hence total cost of 1 MW solar thermal with molten salt thermal storage power plant
is Rs. 60 crores for stabilized uninterrupted quality power.

So 1 MWh produces 1000 unit every 24 x 1000 = 24,000 unit daily

hour, for 24 hrs

Cost of unit sale @ Rs. 5/ unit 24,000 x 5 = 1,20,000

Cost of diesel plant is around Rs. 18 per 24,000 x 18 = 4,32,000

unit

It should be noted that life cycle assessment of solar PV based power is

required replacement of batteries after 5 year in case of Lead acid battery and 10 years

in case of Li-ion batteries. There is no replacement of solar thermal power plant and

continue to run as it maintain. Hence PV based plant cost will be around Rs.

114croresand solar thermal based plant is Rs. 60 crores for stabilized

uninterrupted quality power.

 It can be concluded from above analysis that considering the technical and

economic benefits of solar thermal power coupled with thermal storage technology in

comparison to solar PV system coupled lead acid batteries/Li-ion batteries storage

technology, it is better to opt thermal storage technology even though it is costlier

during initial capital cost. For the 20 years, considering all costs (i.e. capital plus

maintenance) values of Net Present Value (NPV) and Internal Rate of Return (IRR)

would be better for solar thermal energy storage systems.

2.3 THERMAL STORAGE SYSTEMS

Powell et al. [33] observed that CSP or solar thermal power technology is suitable to

couple with any alternative strategies like coal, natural

gas, biofuels, geothermal, photovoltaic (PV), and wind.

Hybridization provides high reliability, efficiency, reduced capital costs due to

resource sharing. Overall system’s efficiency is improved via synergy of the various

resources or energy sources. An additional benefit of CSP technology is the

appropriate for coupling with energy storage systems i.e. thermal energy

storage (TES).

Globally four main CSP technologies are popular for power generation

1. Parabolic Trough (PT)

2. Solar Tower (ST)

3. Linear Fresnel Reflector (LFR)

4. Parabolic Dish (PD)

Solar thermal power plant option in India on the basis of actual DNI of solar radiation

resource assessment (SRRA) and solar Atlas of SRRA. It will also cover the possible

option of thermal storage for solar power plant and 24x7 operational conditions on

various part of the country.

The government of India launched the National solar mission which targeted 100,000

MW of grid connected solar power by 2022. The majority contribution is with solar

PV technologies because of widespread development and reach to grid parity as per

last bidding of Rs 3 per unit cost. However, solar power plant with 24x7 operation,

the same PV power plant combined with MWh batteries cost around 24-25 crores

which is quite expensive and inefficient.

On the contrary, same power with solar thermal plant with thermal storage, project

cost will be lowered or at par with solar PV with stable grid reliability.

India has an opportunity to become a major contributor to development of solar

thermal power. According to India Metrological Department (IMD), clear sunny

weather is experienced for 250-300 days a year by most part of India and it varies in

various part of India region to region. India has highest DNI range to lowest DNI

range (Ladak to Cherrapunji). Therefore depending on technology option available,

the available, the area wise regions need to be sort-out and propose a solution with

technology and storage option.

The different climate zone of various part of India, and suitable technology along with

specific thermal storage systems given in Table 2.4.

 Table 2.4 Different climate zone of various part of India, suitable technologies &

thermal storage systems

Temperature and Parts/regions of India Suitable solar thermal

DNI technologies coupled
with storage systems

High temperature Rajasthan, Gujarat, some part of PTC, ST, LFR and PD
and high DNI Zone Madhya Pradesh, Adhra Pradesh, with all thermal storage
Karnataka, TamilNadu, Bihar,
Chhattisgarh, Orissa and
Maharashtra.
Moderate Delhi Haryana, Uttar Pradesh, PTC, ST, LFR and PD
Temperature and some part of Bihar Chhattisgarh, With molten salt thermal
low DNI Orissa and Maharashtra, West storage
Bengal and North East Region.
Low temperature Leh, Ladak, Kargil and some part Parabolic Dish (PD) with
and high DNI of J&K. cast iron storage
Range

Worldwide accepted thermal storage options are molten salt, stone storage, cast Iron

& wrought iron storage and PCM.

Lappalaineb et al. [34] experimented on hybrid CSP with two thermal energy storage

(TES) at Almeria in Spain and finally validated through simulation, found good

agreement between them. Two thermal energy storage system were (i) pumping

molten salt (MS) from cold tank to hot tank, and (ii) free drainage from the upper

(hot) tank to the lower tank.

It was concluded that molten salt was suitable for CSP and other application i.e.

nuclear power.

Bauer et al. [35] gives an overview of commercial molten salt TES systems for CSP

plants. They explained the outcome on prime decay reaction with nitrite formation

in
the melt and oxygen release and then a secondary decay reaction with alkali metal

oxide formation in the melt and nitrogen/nitrogen oxide release.

Results point out that the kinetic time constants of these two decays are not the similar

under the observed experimental conditions. Therefore, further future work on the

nitrate salt chemistry near the stability limit is required.

Cristina et al. [36] designed, built and tested a molten salts pilot plant at representative

scale of 8 MWhth. Main components i.e. storage tanks, heat exchanger were tested

deeply. It was found that MS TES gave satisfactory results for large commercial CSP

projects.

Cristina et al. [37] observed that in comparison to sensible and latent heat

storage, thermo chemical storage (TCS) systems still needed to be researched

thoroughly.

Energy Demand of World

Firdaus et al. [38] had briefly discussed through the paper that the energy demand of

the world had been huge potential through solar energy. There is a limited role play in

present condition. It consists of the up to date generation of the concentrator and on

how the other parameters comparison and consider the affordable one. Each and every

generation of concentrator are compared simultaneously with each other and further

optimization in concentrator had also been understanding for future scope.

Concentrator

A Dang [39] had discussed the existing concentrating solar technology in his paper.

Apart from that, he had also analyzed the particular concentrator designing,

manufacturing, modification, testing, tracking mechanism, and material in use, optical

and thermal performance. Some modification had also been provided to enhance the
performance of a concentrator. The different focusing concentration technology and

direction vary calculation had been showed.

T Cooper et al. [40] had narrated about the line to point focus concentrator by

maintaining the tracking mechanism on a single axis and reducing the cost of a

collector with the help of such design consideration for the primary concentrator, this

can be achieved while allowing the thermodynamic concentration limit. The proposed

solar concentrator design is well suitable for large scale application with the

concentration ratio 500-2000.

D Gadhiaet al. [41] had worked on the development of parabolic solar collector with

such inputs and collaboration. The slight growth in solar technology the food

processing technology and all other applications. The approved technologies and its

commercialization were successfully installed and benefits were realized. Apart from

that, the feedback of this technology was also given by their users. The clean

development management and formation of eco-friendly environment will safe us and

also our planet earth.

Receiver: T Lee et al. [42] had proposed his motive about the design optimization of

a solar tubular receiver to rise up the working performance. The poor condition which

was affecting its performance was analyzed. The multiple factors affecting the system

performance were such that the length of the receiver, the maximum number of inlet

pipes, porousness and the thermal conductivity of that porous medium. The maximum

possible effect in each variable on certain physical condition like maximum

temperature and pressure drop is identified and the suitable optimal design is sorted

out. Thus the rare design is suggested to grow up the factor of efficiency. Further, this

alternate design will overcome its performance through the manufacturing process.
AL Avila-Marin [43] had completely reviewed the volumetric receiver design to

optimise minimal heat loss. They have given a comparison between the volumetric

receiver and tube receiver with their different working principle and geometry. The

volumetric receiver includes the porous material which easily absorbs the highly

concentrated radiation inside the volumetric structure. Then further the heat is

transferred to the fluid passing through the same structure. It had been widely used in

central receiver system technology. Thus the study concludes about the pre-existing

and up till date volumetric receiver in use was discussed and analysis of various

parameters was given and considered out the best configuration.

R Duggal et al. [44] had numerically identified about the three- dimensional models

of trapezoidal cavity receiver which is in use in linear Fresnel reflector with water as a

heat transfer fluid was analyzed by both. They also fully described the 3D model. The

issue of thermal loss was predicted and certain parameters were noted down and the

effect was also seen with variant losses. On the other hand, the suitable design

considerations were analyzed and an alternate receiver was proposed for further use.

Thermic Fluid

B Gobereit et al. [45] had completely summarized about the computational fluid

dynamics model of a particle receiver gives out the profound information regarding

various known factors related to it and also it is compared truly compared with the

pre-existing prototype. The thermal radiation losses predicted by the CFD model are

totally different as per the estimated one. It is a true concept for increasing the system

efficiency for various solar thermal applications.

MJ Bustamante [46] had described the heat transfer fluids transferring and utilizing

the collected solar heat with the help of solar thermal energy collectors. The solar
thermal collectors are categorized according to the temperature range namely low,

medium and high. Low-temperature solar collectors use phase changing refrigerants

and water as heat transfer fluids. The uses of water-glycol mixtures as well as water-

based nano fluids are obtaining momentum in low-temperature solar collector

applications. The hydrocarbons are also used as refrigerants in many cases. In

medium temperature solar collectors the heat transfer fluids include water, water-

glycol mixtures i.e., trimethylene glycol (green glycol) and also naturally occurring

hydrocarbon oils in various compositions such as aromatic oils, naphthenic oils, and

paraffinic oils in their increasing order at suitable operating temperatures. In high-

temperature solar collector, the synthetic hydrocarbon oils as heat transfer fluid are

used as a fluid of choice in wide applications while other heat transfer fluid are being

used with varying degree of experimental maturity and commercial viability – for

maximizing their benefits and minimizing their disadvantages

A Sinha [47] had reviewed the concentrating solar technologies with the heat transfer

fluid which are recently in use in India. The various kind of heat transfer fluid

possessing variant physical and thermal properties. As per our needs, the

concentrating solar power plant had formed an alternative source in power generation

around rural field area. The installed concentrating solar power plant includes the heat

transfer fluid Therminol VP-1, Synthetic oil, Dowtherm A, etc are in use. Heat

transfer fluid like Hitec salt, dowthermA are very stable compound and is used for

power generation limited to 700 °C. Some alternate sources of energy are essential to

cover up the gap between demand and supply rather than coal. Through this paper, he

had discussed the various properties of each heat transfer fluid with reference to

concentrating solar power plant in India. They also suggested us about the halide

based salt utilization in these plants for small scale power generations in rural areas.
To utilize the phase change material mainly for two different motives i.e., primary for

working of the heat transfer fluid and secondary regarding thermal energy storage.

Solar Thermal Energy Storage

A Sharma et al. [48] had been given a successful review regarding the thermal energy

storage system with the phase change material concept and also its applications had

been discussed in this paper. They have discussed the latent heat storage system with

PCM having a dominant way of storing. There is an advantage of high storage density

and isothermal characteristics in this particular storage. There had been a number of

applications with the PCM with latent heat storage. The various phase change

material had been studied and analyzed about its melt fraction and thermal properties

and. This paper also summarizes the investigation and analysis of the available

thermal energy storage systems incorporating PCMs for use in different applications.

BP Jelle et al. [49] had disserted in their paper on thermal energy storage system

according to phase change material which can lower the energy consumption of the

buildings. The releasing and storing of heat in a certain temperature limit, the inertia

of the building increases and the room temperature becomes stable. The maximum

amount of energy is stored at a high temperature andreturn back at a certain

temperature due to an increase in thermal mass at a narrow temperature range. A high

potential of energy had been saved but not yet that much optimized for building

application purpose. Some known materials with a transition around comfort

temperature, and those existing do have a relatively low heat of fusion.

S Kuravi et al.[50] had narrated about the thermal energy storage technologies and the

factor which are to be considered at different levels in concentrating solar plants. The

thermal energy storage is the vital component in concentrating solar plant for
increasing out the efficiency and the performance. There is a lack of storage system in

solar power plant and the designing along with the integration of the storage system is

not so highly focused to built it. The study of the various thermal energy storage

system is pointedly specified and other economic aspects are also summarized. Thus

the arrangement of the various storage system is required to achieve the expected

efficiency.

S Khare et al. [51] had discussed the alternative source apart from the conventional

energy. The suitable non-conventional energy is solar energy which is eco-friendly in

use. The solar power in India is developing day by day. It is easily available

everywhere also the demand of various sector through solar energy is increasing

widely and if we want to save our environment then we must use solar as a part. In

this paper, the schemes available in India, solar mission, a case study of some

applications, etc. is discussed shortly.

2.4 RESEARCH GAP

After reviewing different research papers, following research gaps are identified:

 Remarkable scope of energy storage is available coupled with solar thermal (CSP)

systems in in hot climatic conditions i.e. India. Only a few concerned research

papers are accessible for making available electricity 24×7 in hot climatic

conditions i.e. India.

 Thermal energy storage system (i.e. solid) coupled with solar thermal (CSP)

systems for the Indian climatic conditions is not found.

 CHAPTER-3
EXPERIMENTAL SET UPS
 Chapter-3 Experimental Set Up

3. GENERAL

Solution towards energy security and various environmental issues is the adoption and

promotion of renewable energy systems. Solar energy has the tremendous scope of

energy generation i.e. electricity and heat both. In this chapter, methodology adopted

for CSP system with energy storage system is presented. The adoptability of solar

thermal system can significantly be enhanced by coupling energy storage system.

Title of the first experimental set up is “1MW electrical (3.5 MW thermal) solar

power plant with 16 hours thermal storage capacity”. The aim of the experimental set

up is to establish a 1MW capacity solar thermal power plant with 16 hours storage

facility based on Parabolic Solar Reflectors at an estimated solar to electric efficiency

of about12%. Title of second experiment set up is “high energy density thermal

energy storage for concentrated solar plant”.

DESCRIPTION OF EXPERIMENTAL SET UPs

Experiment set up-I

Experimental set up-I is established at near Shativan Campus, Bhrahma kumaries,

Talheti, Abu Road-307510, Rajasthan.

Design parameters of the experimental set up-I:

Parabolic Solar Reflector (PSR): 60 SQM PSR is presented as Fig. 3.1(a). It is

completely designed with space frame comprises with solar grade curved mirrors.

Mainly it has four parts (i) Supporting stand (ii) Rotating wheel (iii) Central bar space

frame and (iv) Outer frame with cross bars and long bars.

All the materials used for the PSR are of mild steel grade as per IS 2062 and as per IS

4923 for solid and hollow sections, respectively. All the surface areas are well coated

with paints (epoxy paint and PU paint) for the long life service.

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Chapter-3 Experimental Set Up

Fig. 3.1(a) Parabolic solar reflector

Thermal Energy Density Calculation for Salt Crystals

Thermal energy stored in a solid mass (sensible heat) by raising its temperature can be

calculated as follows:

The heat or energy storage is given by:

Q = V ρ cp dt

Where,

Q = sensible heat stored in the material (J)

V = volume of substance (m3)

ρ = density of substance (kg/m3)

cp = specific heat of the substance (J/kg oC)

dt = temperature change (oC)

Temperature necessary to stored 300 KWh in 1 m3 of Salt Crystals

(Thermal Energy Density: 300 KWh/m3)

dt = Q/ (V ρ cp )

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Chapter-3 Experimental Set Up

Q (in KWh) = Q (in KJ) /3600 (second/hour)

Q (in KJ) = 3600 x 300 = 1.08 x 106 KJ

Q = 1.08 x 109 J

V = 1 m3

ρ = 2200 kg/m3

cp = 870 J/kg

oC

Using the above values, we get:

dt = 565oC

Hence we need the core temperature to rise up to 565 oC to capture and store 300

KWh/m3 of thermal energy density.

SOLAR POWER PLANT WITH 24X7 THERMAL STORAGE

About the Project:-

Project Title:

1MW el. (3.5 MW) solar thermal power plant with 16 hours thermal storage capacity

for continuous operation

Project Number:

15 /13 /2008-09/ST

Government of India, Ministry of New and Renewable Energy, Solar Thermal Energy

Group

Date of commencement of the Project:

December 2010

Ram Krishna Dharmarth Foundation University, Bhopal Page 37

Chapter-3 Experimental Set Up

Date of completion of the Project:

December 2016

Objectives of the Project:-

The Objective of the project is to design, manufacture and establishment of a 1MW

capacity R&D solar thermal power plant with 16 hours storage facility based on

indigenously developed and manufactured Parabolic Solar Reflectors at an estimated

solar to electric efficiency of about 12%. The configuration of the project includes

770 no’s of 60SQM each Solar Reflectors with each having thermal storage receivers.

Key Features of the project includes:

• 770 no’s of 60SQM parabolic Reflectors with automatic dual axis tracking

mechanism with network enabled monitoring

• 770 no’s of Static Thermal storage Receivers for 16 hours thermal storage for

night operation

• Direct steam generation at the focus of each parabolic reflector

• 6500 kgs of superheated steam generation every hour for continuous24 hour’s

capability

• 1.2 MW el. Capacity two stage Turbine and Generator

• Fully automatic off-grid power generation as per real time demand

Output of the Project:-

a. Nature of Output:

• Peak output up to 1.2MW electric power output per hour

• Thermal storage for 16 hours for continuous operation of the plant

• Direct steam generation at focus

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Chapter-3 Experimental Set Up

• Steam output with acceptable parameters from 252oC to 410oC

temperature and operating pressure from 38Bar to 44 bar atmospheric gauge

pressure

• Total steam production of 6500 kgs per hour

b. Performance Specifications:

• 60S QM Parabolic Solar Reflector:

i. Each Reflector can generate thermal energy output up to 170kwhrsper

day

ii. Each Reflector can concentrate up to 1200o C temperature at focus

• Thermal storage Receivers:

i. Each Receiver can store thermal energy up to 150 kwhrs per day

ii. Direct steam generation of temperature ranging from 250o DegCto

450DegC at operating pressure from 38 Bar g to 44 Barg

• Overall plant output:

i. The overall plant produces 7000 kgs of steam every hour for continuous 24

hours plant operation.

ii. Turbine – Generator can produce peak of 1.2MW of power output per hour

iii. The thermal storage allows the plant to run on continuous basis round the

clock. It also allows the plant to generate power as per demand.

All the surface areas are protected with epoxy paint coat and marine protection PU

paint coat on the properly cleaned surface through copper slag blasting.

Main components of 60SQM Parabolic Solar Reflector:

Main parts of Parabolic Solar Reflector

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Chapter-3 Experimental Set Up

Supporting Stand: Concrete foundation is done for providing proper strength to 60

SQM Parabolic Solar Reflector as shown in Fig 3.1 (b). Designing of stands is done

according to latitude of the location, hence different design is done for different

locations. Base of supporting stand is selected in triangular shape for providing proper

strength with less land requirement.

Parabolic Solar Reflector: This supporting stand requires design as per the latitude

of the location; hence different revision of design is required for different locations.

The base of the supporting stand is designed in triangular shape for more stability and

less land requirement. All the materials used for the designare of Mild steel grade as

per IS2062 and M.S. Sections as per IS4923. The design is analyzed through space

frame design for dead load as well as wind load. All the surface areas are protected

with epoxy paint coat and marine protection PU paint coat on the properly cleaned

surface through copper slag blasting.

Fig 3.1 (b) Supporting Stand

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Chapter-3 Experimental Set Up

Rotating Wheel: It links to supporting stand and parabolic frame, as Fig. 3.1(c).

Materials employed for rotating wheel are of mild steel grade as per IS 2062 and M.S.

sections as per IS 4923. The daily tracking arrangement is through rack and pinion

arrangement with actuators and DC motor for daily rotation.

Fig 3.1 (c) Rotating Wheel

Parabolic Outer Frame: The next main component of the Parabolic Reflector is the

parabolic frame. The outer frame is designed in three parts as per the requirement of

flexibility and rigidity balance to accommodate various shapes of parabola’s for

different seasonal requirements. This outer frame provides hinge support to various

cross-bars and long-bars that are designed to support the mirror pieces that make a

perfect parabolic reflective surface, as Fig. 3.1(d).

Central Bar Space Frame: It is a backbone of the outer parabolic frame. This is used

for tracking mechanism on the longitudinal axis of the parabola. This has three

mechanical actuators that are driven by DC motors. This structure due to its flexible

behaviors enhances the concentration ratio of the output focus at the focal point.

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 Chapter-3 Experimental Set Up

Fig 3.1 (d) Parabolic Outer Frame

Flexible Parabola: The structural design has the flexibility option in the structure to

provide flexible parabola, presented as Fig. 3.2. There is different parabolas option for

different seasons. These flexible parabolas are possible through automatic dual axis

tracking mechanism. There are three types of tracking systems:

(i) Daily tracking: This tracking mechanism allows the Reflector to track the sun
throughout the day. This is done with the help of rack and pinion mechanism.

(ii) Seasonal tracking: This tracking mechanism allows the Reflector to align with the
changes in the angle of the sun due to change in the season.

(iii) Shape change tracking: This tracking mechanism allows the reflector to change the
shape of the parabola to increase the concentration ration of the focus.

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Chapter-3 Experimental Set Up

Fig. 3.2 Flexible parabola

All the three types of tracking systems are fully automatic coupled with mechanical

actuator (D1) and shape change actuators (S 1,S2,S3,S4), DC motors, micro controller

and programming systems, that all is referred as “IMATRACK POWER”, as Fig. 3.3.

It tracks to 60 SQM PSR.

Fig. 3.3 various actuators

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Chapter-3 Experimental Set Up

Static Cast Iron Cavity Receiver:

A) Receiver is constructed by monolithic cast iron, in conical cavity shape,

opening of 500 mm and 700 mm deep in conical design. A single helical

boiler grade coil is wound around the monolithic conical cavity cast iron body

around the periphery, as Fig. 3.4.(a,b,c)

(a)

B) Single helical boiler grade coil is wound around the monolithic conical cavity

castironbodyaroundtheperiphery;thiscoilhasinletatoneendandoutletatthe other

end. This coil acts as heat transfer material from thecast iron body to the water

flowing in the coil. This heat transfer enables the water to convert into steam

in the coilitself.

(b)

Fig. 3.4 (a) Receiver coil drawing (b) Block drawing

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 Chapter-3 Experimental Set Up

C) The entire body of the Receiver is covered with mineral wool Insulation of 6

inch thickness with aluminum cladding to minimize heat loss to atmosphere.

The Receiver is supported and mounted on a triangular structure for better

stability and supported with fixtures that minimize heat loss due to heat

transfer.

Fig. 3.4 (c)

The whole body of receiver is shielded by mineral wool insulation of 6-inch thickness

with aluminum cladding to decrease heat loss to air. Receiver is mounted on a

triangular structure with fixtures to provide stability with minimum heat loss.

Experiment set up-II

Experimental set up-II is established at Ram Krishna Dharmarth Foundation (RKDF)

University, Bhopal. Details of equipment used in experimental set up-II (as shown in

Table 3.1)

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 Chapter-3 Experimental Set Up

Table 3.1 Equipment list used in the experimental set up

Sl. Name of Specifications Make / Cost Date of Utilization Remarks

No Equipment Model (FE / Rs) Installation Rate (%) regarding
Maintenance /
Breakdown
Tracker Unit Assembly
complete with Micro-
Controller with Computer
1. Solar Tracker Unit Interfacing Facility and full 7,04,175.00 23rd 100%
auto operation throughout the Jan,2016 Control System
year and data logging system. Components
Replaced
Piping work was
revised for better
D4#23P steam generation
Heat Transfer Unit Plunger Type Positive Return SR NO: CE- and the Core s
(Boiler Feed Pump & Metering; 0-50 LPH with 5606 26th under revision to
2. 2 1,19,914.85 75%
Piping & Core of MS discharge pressure 11kg/cm ; Dosing Mar,2016 Cast-Iron
and Copper) Flooded suction; Pump speed Metering crucible design
– 145 RPM; All material SS Pump for improving
316 ; Plunger – Hard Chrome steam
Plated parameters.
Core Material from Mild Steel, Copper and Cast- Size of Crystal
3. 3,38,401.00 7th 75%
RPI USA Iron revised
May,2016
HS
1100mm(dia.) x 5mm(thick); 71171900000
4. Fresnel Lens MMA Polymer; Focal Focal length 31,000.00 23rd 100%
Jan,2016 -
Length of 1300mm 1300mm
1100mm Dia.

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Chapter-3 Experimental Set Up

Other materials are

1. Thermocouple R-Type ; 360mm Long; 0-1500o C range ; Compensating Cable

SS braided and Digital Meter along with accessories.

2. Thermo-Electric Device duly designed and fabricated at Micro-and Nano

Fabrication Clean Room (MNCR), RPI, USA. Conversion Efficiency more than

5%.

3. Thermal Storage Salt for Research developed at the RPI Lab, USA and imported

vide invoice dated 25th April, 2016- having high “Energy Density” exceeding

300kWh/m3and Density 2200kg/m3.

The aim of this project is to demonstrate a solar thermal storage system with 1 kW

capacity of volumetric energy density, exceeding 300 kWh/m3 and capable of

operating at high temperatures up to 1000 oC. In comparison, the volumetric energy

storage density for water is typically around 80 kWh/m 3 and 200 kWh/m3 for molten

salts used in solar thermal plants. The unique aspects of this system are the selection

of an alkali halide salt with high melting temperature and a corrosion-resistant, low-

cost ceramic container material. Flux grown crystals of mixed alkali halide

compounds doped with metallic impurities shown as Fig. 3.5. The thermal storage

unit is coupled with a high solar concentrator system (1000 – 10,000 Xs).In this

project, we propose to develop and demonstrate an affordable, high energy density

thermal storage system that can store heat at temperatures around 1000 oC. Cast-iron

core crucible design and schematic are presented as Fig.3.6 and 3.7, respectively.

Solar thermal storage with solar tracker unit is shown as Fig. 3.8 and 3.9.

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Chapter-3 Experimental Set Up

Fig. 3.5 Size and photo mixed alkali halide compounds doped with metallic impurities

Fig. 3.6 Cast-iron core crucible design

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Chapter-3 Experimental Set Up

Salt Crystals Focus Area

Solid CastIron Core

Quartz Glass for Lid Heat Exchanger

Fig. 3.7 Schematic of experimental set up

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Chapter-3 Experimental Set Up

Fig. 3.8 Installation of the solar thermal storage and solar tracker unit

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Chapter-3 Experimental Set Up

Fig. 3.9 Solar thermal storage with solar tracker unit

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Chapter-3 Experimental Set Up

Fig. 3.10 Tracking motor

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Chapter-3 Experimental Set Up

Fig. 3.11Tracking rope & Chain

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 CHAPTER-4
EXPERIMENTAL DATA ANALYSIS,
RESULTS & DISCUSSIONS
Chapter-4 Experimental Data Analysis,
Results and Discussions
4. GENERAL

CSP coupled with storage system is the promising technology for 24×7 energy

supply. Experimental results of both the arrangements are satisfactory. It is observed

from experimental results that solid storage systems are the appropriate option.

PERFORMACE OF REFLECTOR ROUND THE YEAR

(Experimental Set up-I)

The aperture area of the reflector is as shown in Fig. 4 changes occur in different

seasons as per the inclination with the polar axis.

Fig. 4.1 Changes in aperture area of reflector

Variation in the aperture area for a 60 SQM Paraboloid reflector round the year is

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 Chapter-4 Experimental Data Analysis,
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Detailed Project Report

a. Experimental works carried out :

First Prototype Receiver testing setup and result:

Thermal Storage Receiver Testing & Results:

i. Measuring system setup for first Prototype: The schematic diagram

explains the set-up of the measuring system to evaluate the 60m2

Paraboloid Reflector and the static cast iron receiver. Components

involved in the Measuring system:

ii. 60 SQM Paraboloid Reflector 4 no’s of Temperature sensors Type K

embedded in the Receiver

iii. Pressure sensor and temperature sensor to measure steam parameters

iv. Campbell data logger to record the measurements (temperature and

v. Weather station (Shadow ban redo meter, Direct normal radiation DNR,

Wind Speed, Wind direction, Air temperature)

The measuring systems consist of two subsystems: Subsystem one collects the data of

the receiver, while subsystem two is the heart of the weather station, both subsystems

collect data through Campbell CX 1000 data loggers Receiver system

The measuring system of the receivers consists of 4 receiver temperature sensors

(type K thermocouples), a water meter, a steam pressure sensors as well as a

temperature sensor for the water and for the steam (type K thermocouples). The water

meter allows the manual reading of the water flow and the amount of water injected

into the receiver. The data is collected with a Campbell CX1000 data logger. The

pressure sensor is from Siemens pressure transmitter of required pressure range.

Following are the results obtained from the tests carried out with below setup:

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Chapter-4 Experimental Data Analysis,
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The thermal behavior of the Receiver without front glass

The testing was carried out in the month of May 2011 with them ensuring set-up as

shown in Fig.4. The Static receiver is charged during the day time through the solar

rays’ reflection focus from the Para bloodier reflector.

The Receiver is charged without front glass covering.

Fig. 4.2 Measuring System 1 and 2 for the receiver and solar radiation

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 Chapter-4 Experimental Data Analysis,
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Detailed analysis of report–

a) Simulation report of thermal behavior of 5 no. of Receivers in series:

Simulations were done in the ‘colsim’ simulation environment, for the cast iron

receiver in series connection to determine the thermal behavior pattern and to

determine the thermal storage duration for further simulation of the plant:

Following observations and assumptions were considered in the simulation of 5

receivers in series:

 The functioning of the Receiver model considered for simulation has been

matched and the parameters of the Receiver model were adapted to fit the

actual results obtained from testing the first prototype receiver.

 In this simulation receivers with equal mass in series of 5 no’s is considered.

 Actual averaged Weather data for three years is considered for the timeframe

used in this simulation report.

 Various other assumptions for mass flow rate of fluid (in this case water), with

receiver front glass position are studied for thermal storage behavior.

 The max mean temp. Achieved by charging the receiver is assumed as 500 oC,

while the minimum temp till discharge the receiver is assumed as 260oC.

 The receiver geometry is idealized to cylindrical structure geometry and is

divided into equally spaced different subsections of the cylinder representing

different temperature gradients along with the length of the heat transfer coil.

 The incoming radiation, the absorbed radiation, the heat transfer between

different subsections and the heat transfer coil, the ambient losses are all

considered and matched in the simulation results according to the actual

achieved test results of single prototype receiver.

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To summarize, the assumptions in this study are:

 One-dimensional heat transfer.

 Constant heat conduction coefficient for cast iron (line system).

 Every node has same amount of volume.

 Numbers of turns in helix are equal to the number of nodes.

 Reflections inside the cavity are neglected.

 There is no temperature gradient from cavity to outside diameter of the

cylinder.

 Thermo physical properties of fluid are same at every point inside the

specified pipe section.

 Storage is composed of a cylindrical block of cast iron. To analyses the heat

transfer between the cast iron nodes, the block is divided to 20 cylindrical

shaped nodes.

Fig.4.3 Results for the temperature distribution in the storage under specific
operation temperatures are presented the figure below

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Chapter-4 Experimental Data Analysis,
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b) Heat Loss and Radiation for different Receivers in a module:

Figure shows the heat losses to ambient (Q_loss, upper graph) and the heat gain

through absorbed radiation (Q_rad, lower graph) of the first and last receiver in a

module. The heat loss in the last receiver is significantly higher (almost by a factor 2)

than the loss of the first receiver due to the lower average temperatures of the first

Receiver. The first Receiver can accept up to 35% more incident radiation (as

compared to the last receiver) until the overheating protection requires to cover the

Receiver door.

Fig. 4.4 Heat Loss and Radiation for different Receivers in a module

Le8: Thermal losses – heat losses Le9: Thermal input – heat gained

Orange curve – is for first Receiver in Series Green Curve – is for last Receiver in

series

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Chapter-4 Experimental Data Analysis,
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c) Simulation report of thermal behavior of 10 no. of Receivers in series:

Simulations were done in the ‘colsim’ simulation environment, for the cast iron

receiver in series connection to determine the thermal behavior pattern and to

determine the thermal storage duration for further simulation of the plant:

Following observations and assumptions were considered in the simulation of 15 no’s

of receivers in series:

 The functioning of the Receiver model considered for simulation has been

matched and the parameters of the receiver model were adapted to fit the

actual results obtained from testing the first prototype receiver

 In this simulation receivers with equal mass in series of 15 no’s is considered

 Actual averaged Weather data for three years is considered for the time frame

used in this simulation report.

 Various other assumptions for mass flow rate of fluid (in this case water), with

receiver front glass position are studied for thermal storage behavior.

 The max mean temp achieved by charging the receiver is assumed as 500 oC,

while the minimum temp till discharge the receiver is assumed as 260oC.

 The receiver geometry is idealized to cylindrical structure geometry and is

divided into equally spaced different subsections of the cylinder representing

different temperature gradients along with the length of the heat transfer coil.

 The incoming radiation, the absorbed radiation, the heat transfer between

different subsections and the heat transfer coil, the ambient losses are all

considered and matched in the simulation results according to the actual

achieved test results of single prototype receiver.

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 Chapter-4 Experimental Data Analysis,
Results and Discussions

d) Controller settings for this simulation:

The temperature control mechanism was discussed and finally it was concluded to

deactivate the closing of Receiver door. In consequence, in the simulation model, an

overheating of receivers is allowed and more heat can be extracted. It was further

agreed not to implement day time discharge at this point, button neglect minor

differences (mainly the slightly higher heat losses if no daytime discharge is allowed

but instead the receivers may overheat) arising from this simplification in the

simulation. A crosscheck with the Iatric settings revealed that the assumed 140° angle

span (see previous case) was still overestimated. The actual value is 130° and this

value was used.

Only parameters varied throughout this report are stated below; parameters varied

w.r.t. the previous simulations are indicated by bold cursive letters:

PAR1Max. AVERAGE storage temperature 900°C (deactivated) PAR3 Min steam

temperature 260°C

PAR5 Mass flow rate 240 kg/h

PAR6 Steam pressure 44 bar

PAR7 Feed water temperature 105°C PAR9 Daily rotation angle span 130°

Weather data used: downscaled Metronome data. Mass of all receivers: constant,

4100 kg

Simulation results:

To quickly give an indication on the effect of higher masses, reduced heat loss. Only a

short period of time of 12 days of January has been simulated. The variability of

results is shown in the figure below. From this we conclude that we may choose the

day Jan 7 as representative ‘good day’ for this month. The detailed evaluation and

comparison of cases is done only for this day and presented in the following. Below

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 Chapter-4 Experimental Data Analysis,
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table Accepted radiation, thermal losses and thermal gains of all receivers (1 – 15) in

the module (for Jan 7) and their relative contribution to the total radiation / loss / gain

of the module. All receiver masses are equal, 4100 kg. . Equal distribution would be a

contribution of 6.7 % (1/15 %) for each receiver.

Table 4.1 Simulation results

Testing works carried out:

After the successful testing of the first prototype Receiver in May 2011 and

conducting simulations through the simulation software “Colsim” simulation

environment for both single receiver as well as 5 no’s of Receiver sin series and

subsequently 15 no’s of Receivers in series as discussed above; it was clearly evident

that we shall go for monolithic cast iron receiver around the conical cavity from all

the three sides, with proper insulation to minimize the thermal losses.

Accordingly, the testing set-up was set for practical testing and measurements to

further explore different heat transfer design concepts and to confirm the results seen

in the simulation results for 15 no’s of Receivers in series. Here below, we share the

testing results for all the testing works carried out in two phases:

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Chapter-4 Experimental Data Analysis,
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1. Single monolithic cast Iron cavity Receiver with different heat transfer design

concepts

2. 10 no’s of monolithic cast iron receivers in series with different mass flow

rates

L31 Receiver features ‘Receiver with heat transfer paste:

1. Conical cavity receiver
2. Weight – 3710kg
3. Length – 1meter
4. Coil length – 31meters,
5. Coil Pitch – 75 mm. Coil is wrapped around the casting, heat transfer paste
was applied to fill the gaps between cast Iron block and coil.
6. Temperature sensors detail:
7. Temp EF – Temp east front, Temp EB – Temp east back
8. Temp WF – Temp west front, Temp WB – Temp west back

Fig. 4.5 Receiver Charging-Discharging

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Chapter-4 Experimental Data Analysis,
Results and Discussions

L21 Receiver features ‘Receiver with grooving’:

 Conical cavity receiver

 Weight – 3610kg

 Length – 1meter

 Coil length – 31meters,

 Coil Pitch – 75 mm. casting was machined to have groove made of the exact

size of the coil diameter, coil was fitted inside these grooves. (Photo 4,

Photo5)

 Temperature sensors detail: Temp EF–Tempeast front, Temp EB–Tempeast

back Temp WF – Temp west front, Temp WB – Temp west back

Fig. 4.6 Receiver with grooving’

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 Chapter-4 Experimental Data Analysis,
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Work carried out

a) Process Flow Diagram for India One solar plant:

The plant operates on Rankine cycle principle. The Parabolic Reflector concentrates

the solar radiation towards the in-house developed, highly efficient cavity receiver.

The cavity of the Receiver which is made of monolithic cast iron acts as perfect black

body and thus provides excellent thermal storage. The boiler grade coil around the

body acts as a heat exchanger which allows for water to exchange heat and convert

into steam.

Fig. 4.7 India One solar plant

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Chapter-4 Experimental Data Analysis,
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The thermal storage can be operated between 250 oC to 550oC and can be discharged

on demand. The steam generated is mostly superheated steam and the rest is saturated

steam at operating pressure from 38Bar to 44 bar gauge pressure.

The total field is divided into 23 no’s of modules. Each module has receivers

connected in series and each module has been named with an alphabet starting from

‘A’ from the North to ‘W’ to the south; the number of Receivers ranges from 20no’s

to 45no’s as per the availability of the space. The output of all the modules is

connected to the steam header that carries steam to the steam turbine.

The plant is designed as a captive plant (off grid) as per demand to provide electricity

to the headquarter campus Shantivan at Abu Road, Rajasthan.

b) Typical P&ID of a solar module from ‘India One’ solar power plant:

A typical module consists of multiple cast iron cavity Receivers in series, the no’s of

Receivers in series depends on the layout and land availability. The no. of Receivers

ranges from minimum13no’stomax.45no’s in series, each module (each row) is given

Alphabet for identification starting from ‘A’ from the north of the lay out to ‘W’

ending towards the south of the layout. Each module is aligned in exact east-west

direction facing south and receiving solar radiation on the reflective surface. The

numbers of Receivers in series for each module is given in the table here below:

Since there are 23 no’s of modules in the field, therefore there are also 23 no’s of

piston pumps (positive displacement pumps), i.e.: one pump per module. Each

module acts like a boiler that delivers superheated steam to the steam header. The first

35% of Receivers in series in a module act like economizer that heats up water into

steam, the next 35% of Receiver sin series in a module act to generate saturations

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Chapter-4 Experimental Data Analysis,
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team and the last 30% of Receivers act like super heaters to generate superheated

steam which is then finally connected to the steam header. The required operating

pressure of steam is delivered by piston pump at the inlet of the module. The mass

flow rate of the pump is controlled by VFD (variable Frequency drives) that take their

input signal of operation from the centralized pressure control mechanism which in

turn takes signal throughout put frequency of generator. The plant is off grid

connected to the Brahma Kumar is campus that has load demand that can cater

to25,000 people for lodging and boarding. Hence, the load demand is indirectly

transferred to the VFD of the pumps which synchronizes the demand with the supply

and accordingly varies the mass flowrate of the water which then converts into steam

and goes to the steam turbine. The mass flow rate for each module is programmed as

per the length of the module i.e. number of Receivers in series for the module. The

bigger the modules the bigger is the flowrate through it. In this way, the complete

solar thermal field with each module has synchronized thermal behavior of charging

and discharging. Each module is installed with analog as well as digital

instrumentation that reads the important parameters related to pressure, temperature.

Also, each module is treated as a boiler and accordingly, each module is having

dedicated safety valve. Also, the module is equipped with strainers, Isolation valves

and Non-return valves wherever necessary for smooth operation and maintenance. All

modules have common water header on inlet side and common steam header on the

outlet side. Thus, the modules derive water from the common water header and

supply steam generated to the common steam header.

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 Chapter-4 Experimental Data Analysis,
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Quantity of steam to Turbine

The steam Turbine allows certain quality of steam for its functioning it requires steam

of pressure ranging from 38BarG to 44BarG and temperature ranging from 252 oC to

410oC. And minimum quantity of steam starting from 4000 kgs to 6500Kgs therefore

it is very important that the solar thermal field generates steam of the required quality

and quantity of steam. In order to derive this steam form the solar filed, PID logic is

implemented in the control logic that ensures the requirement. The scheme is shown

in the following diagram:

Fig.4.8 PID logic implemented in the control logic

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 Chapter-4 Experimental Data Analysis,
Results and Discussions

P&ID’s of various sub systems

(a)

(b)

(c)

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Chapter-4 Experimental Data Analysis,
Results and Discussions

(d)

(e)

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Chapter-4 Experimental Data Analysis,
Results and Discussions

(f)

(g)
Fig. 4.9 (a) to (g) P&ID’s of various sub systems

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Chapter-4 Experimental Data Analysis,
Results and Discussions

Operating Parameters for Turbine

Operating data and limit value

Table 4.2 Operating data and limit value (Turbine1)

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Chapter-4 Experimental Data Analysis,
Results and Discussions

OPERATION PARAMETERS AND RESULTS:

The project is commissioned in two phases–first phase is commissioned in November

2016 with 300 no’s of Reflectors commissioned, which is the minimum number

required to generate quality steam for steam turbine to operate.

The second commissioning is completed in May 2017 withal 770 no’s of Reflector

modules commissioned. The project started in full potential from October 2017 with

good solar radiation period. Soon after the complete commissioning of the plant with

all the sub- systems stabilized to its full potential, the plant achieved record power

generation for maximum number of hours of operation without any halt.

Another milestone achieved by the plant of the peak output generation. The maximum

peak output delivered by the plant till date is 920 KW. Please see here below the

screen shot of the peak output delivered by the plant.

Fig. 4.10 Operation parameters and Results

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Chapter-4 Experimental Data Analysis,
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Solar & Thermal Benefits Accrued:

List of Technical documents prepared:

1. Output estimation and consideration for field layout based on

Solar radiation data at “India One” – by Heike Hoedt – JULY 2011:

Following research aspects are discussed and achieved in this report:

a. This report establishes the output achieved by the solar reflector with respect

to the solar radiations data received at “India One”

b. This report elaborates the mathematical model done to establish the total

numbers of solar reflectors with desired output with respect to the solar

radiations data received at “India One”

c. Establishment of adequate numbers of standing and lying solar reflectors to

match the climate based output variations to achieve the required output in the

best possible way

2. Consideration of Field layout based on simulation of shadowing effect at “India

One” – by Heike Hoedt - November2011:

Following research aspects are discussed and achieved in this report:

a. A model of 1:80 was used to study the shadow effect on the probable field

layout of 60m2 solar reflectors

b. Setup of only standing reflectors was developed and considered

c. Grid size with adequate distance was determined using the shadow effect on

the reflectors at various timings during the sunlight

d. Piping losses were evaluated against shadow losses. Conclusion smaller grid

of 11mx13m is recommended

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Chapter-4 Experimental Data Analysis,
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3. Design & Installation of 60m2 Parabolic Dish and Receiver /Storage at “India One”

– by Wolfgang Scheffler – October2011:

a. All aspects of design for 60m2 solar reflectors are discussed and established

b. Basic aspects of Receiver design are discussed and established

Output estimation and consideration for field layout based on

Solar radiation data at “India One” – by Heike Hoedt – JULY 2011:

Following research aspects are discussed and achieved in this

report:

a. This report establishes the output achieved by the solar reflector with respect

to the solar radiations data received at “India One”

b. This report elaborates the mathematical model done to establish the total

numbers of solar reflectors with desired output with respect to the solar

radiations data received at “India One”

c. Establishment of adequate numbers of standing and lying solar reflectors to

match the climate based output variations to achieve the required output in the

best possible way

4. Consideration of Field layout based on simulation of shadowing effect at “India

One” – by Heike Hoedt - November2011:

Following research aspects are discussed and achieved in this report:

a. A model of 1:80 was used to study the shadow effect on the probable field

layout of 60m2 solar reflectors

b. Setup of only standing reflectors was developed and considered

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Chapter-4 Experimental Data Analysis,
Results and Discussions

c. Grid size with adequate distance was determined using the shadow effect on

the reflectors at various timings during the sunlight

d. Piping losses were evaluated against shadow losses. Conclusion smaller grid

of 11mx13m is recommended

5. Design & Installation of 60m2 Parabolic Dish and Receiver /Storage at “India One”

– by Wolfgang Scheffler – October2011:

a) All aspects of design for 60m2 solar reflectors are discussed and established.

b) Basic aspects of Receiver design are discussed and established.

6. Design options for the mirror mounting at “India One” – by Heike Hoedt – March

2012:

a. Various design options for the mirror mountings are developed and

established.

b. Final design for the mirror mounting concluded based on the most cost

optimized design solution.

7. Design and Installation of a measuring system to evaluate the 60m2Parabolic dish

and Receiver Storage at “India One” – by Thorsten Ludwig – May2012:

a. Setting up of Measuring system to evaluate the 60m2 parabolic dish and

Receiver Storage using various Instrumentation set up comprising of

thermocouples and data loggers with process piping and Instrumentation

required.

b. Output of the Receiver with various flow rates and at various solar radiation

with various position of the receiver (door open /door closed) was studied and

conclusion was derived for output and efficiency of the Receiver.

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Chapter-4 Experimental Data Analysis,
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c. Thermal losses of the Receiver were evaluated under different conditions. Up

to 82% of solar radiations are absorbed by the Receiver (loading efficiency),

up to 65% of the overall efficiency was observed.

7. Experimental Investigation of Heat transfer between cast Iron grit and various

mixtures at “India One” – by Atul Singh – June2012:

a. Investigate heat transfer characteristics of CI Grit and various mixtures

b. Found an optimum mixture of CI Grit with other materials.

8. Report on test performed on Modified Receiver at “India One” – by Atul Singh –

June July 2012:

a. Output of the Modified Receiver with various flow rates and at various solar

radiations with various position of the receiver (door open / door closed) was

studied and conclusion was derived for output and efficiency of the Receiver.

9. Control System for “India One Solar Power Plant” – by Jurgen Holstein –

March2011:

a. Centralized tracking, monitoring of the solar reflectors fromcentral control

room

b. Discharging of the receivers through the centralized network according to the

pumping philosophy

c. Monitoring and control of the Turbine and Generator

d. naturalized monitoring and control of the Balance of plant

e. Initial Power requirement to start and restart of the India one plant

f. Power consumption monitoring, Controls and Alarm transmission system on

the power evacuation side of the plant

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Chapter-4 Experimental Data Analysis,
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10. Report on the Controls of tracking the 60m2 solar reflector and alerts from the

central controller at India One – by Jurgen Holstein – March2011

“India One” simulation results – module of 15 receivers in series – by Fraunhofer ISE

– March2013

a. A Module of 15 Thermal Storage Receivers in series was simulated.

b. Thermal behavior of the first Receiver and the last Receiver in series is studied

in detail.

c. Thermal losses and the Thermal efficiency of the first and the last Receiver are

quantified.

d. Total average thermal energy output of single Receiver is quantified from the

simulation

11.“India One” – Modular testing & analysis of solar Receiver with storage to study

the thermal behavior for round the clock operation – by WRST Team – April2014

a. A Module of 10 no’s of Thermal Storage Receiver in series was tested and

analyzed.

b. Total average thermal output from 10 no’s of receivers in series for continuous

18 hours was documented

c. Total average thermal energy output of single Receiver is quantified and

documented from the test results.

d. Thermal behavior of the first Receiver and the last Receiver in series results

were analyzed and documented.

e. Thermal losses and the Thermal efficiency of each receiver was analyzed and

documented

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 Chapter-4 Experimental Data Analysis,
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12. Power Consumption for fully automatic tracking system on 60sqmparaboloid

Reflector – by WRST team – August2014

a. Power consumption without optimization for fully automatic tracking system

on 60 sqm paraboloid Reflector is tested and documented.

b. Optimization frequency for the fully automatic tracking system on 60 sqm

paraboloid Reflector is concluded.

c. Required sizing for the power convertors from AC to DC was analyzed and

concluded for further detail engineering.

13. Network requirements for 770 no’s of fully automatic tracking system on 60 sqm

paraboloid Reflector – by WRST Team – August2014

a. Various options for networking were studied, tested, analyzed like Wireless /

Wired networks

b. Cost implications and cost optimization with all options was studied and

concluded.

c. Detail BOQ for the total plant of 750 no’s of fully automatic tracking system

on 60 sqm paraboloid Reflector layout was worked out and documented.

Manpower trained under the project:

In May, 2014 the World Renewal Spiritual Trust was awarded with an assignment of

Development of Awareness Cum Training Centre on Concentrating Solar Thermal

(CST) Technologies under UNDP-GEF Assisted Concentrated Heat Technologies

Project, the Ministry of New and Renewable Energy, Government of India.

The CST Center is located at “India One” Solar Thermal Power Plant, Brahma

Kumaris, Shantivan Campus in Abu Road, Rajasthan

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 Chapter-4 Experimental Data Analysis,
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Objectives of the CST Center:

To create awareness among various groups of stakeholders from industries,

institutions & commercial establishments through

i. end user seminars

ii. manufacturing workshops

iii. Technology demonstration

 To help generating proposals for installations of CST based system sat their

establishments

 To support the capacity building of CST

manufacturers and entrepreneurs quality standards in CST especially of

mirror reliability, durability, performance improvements. Manufacturing

skills, customization of end user products /systems etc.

Scope of Activities:

 9 seminars for potential beneficiaries from industries, institutions&

commercial establishments

 6 training programs in Scheffler technologies for manufacturers. Trainees will

be exposed also to other technologies

Apart from this, around 300 personnel (skilled manpower) have been trained for

installation, commissioning, operation and maintenance of the “India One” solar

plant.

Ram Krishna Dharmarth Foundation University, Bhopal Page 80

Chapter-4 Experimental Data Analysis,
Results and Discussions

60

50

40

30

0306090120 150 180 210 240 270 300 330 360390

Day of the year

Fig. 4.11 Variation in the aperture area

The thermal output from the reflector is computed by the aperture area of the

reflector, the Direct Normal Irradiance (DNI) and the efficiency factor of the reflector.

The efficiency factor of the reflector depends on different things i.e. mirror

reflectivity, surface of mirror cleaned, purity and accuracy of mirror, normally it is

taken 60% as efficiency factor of reflector surface. Actual DNI is calculated on the

location for every 10 mins and averaged out for hour and then for the day. So the

output of Reflector = aperture area (SQM) x avg. DNI for the day (kWhrs) x

efficiency factor. Ave. DNI of the location for the year 2010 is shown as Fig. 4.13.

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Chapter-4 Experimental Data Analysis,
Results and Discussions

DNI… DNI Radiation in kWhr/day from avg. month 2016

6.03 5.91
7.0 5.62 5.63
5.44 5.40 5.25
5.00
4.01
4.00 3.55
2.96
3.00

2.00 1.49 1.31

1.00

0.00
1-May-

1-Jun-

1-Nov-
1-Jul-

1-Oct-
1-Aug-

1-Dec-
1-Sep-
1-
1-

1-

1-

Fig. 4.12 Ave. DNI of the location for the year 2016

Thermal output of 60 SQM reflectors for the year 2016 is shown as Fig. 4.12.

Fig. 4.13 Thermal output of 60 SQM reflectors for the year 2016

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Chapter-4 Experimental Data Analysis,
Results and Discussions

THERMAL BHAVIOR OF RECEIVER

1. Without front glass

The testing was carried out in the month of May 2011. The Static receiver is charged

during the day time through the solar rays’ reflection focus from the Paraboloid

reflector, shown as Fig. 4.14.The Receiver is charged without front glass covering.

Observation: Max. Temperature recorded is 400 oC

Fig. 4.14 Thermal behavior of the Receiver without front glass

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 Chapter-4 Experimental Data Analysis,
Results and Discussions

2. With front glass cover at receiver opening as shown Fig. 4.16.

Observation: Max. temperature recorded – 450 oC

Fig. 4.15 Thermal behavior of the cover at receiver opening front glass

3. With front glass covering at the receiver opening and with water flow

through the heat transfer coil, shown Fig. 4.16.

Observation:

 Flow rate of water through the heat transfer coil – 3.5 litrs/min.

 Max. temperature reached at the Receiver – 450 oC

 Max. pressure of steam discharged – 42 bar

 Max. temperature of steam discharged – 430 oC

 Discharging 2/3rd of time superheated steam and 1/3rd of time saturated steam
before rapid temperature drop.

Ram Krishna Dharmarth Foundation University, Bhopal Page 84

Chapter-4 Experimental Data Analysis,
Results and Discussions

Fig. 4.16 Thermal behavior of the Receiver with front glass covering at the receiver

opening and with water flow through the heat transfer coil

Ram Krishna Dharmarth Foundation University, Bhopal Page 85

Chapter-4 Experimental Data Analysis,
Results and Discussions

PERFORMACE REPORT

(Experimental Set up-II)

Project commenced on 6th September, 2015 then completed on 18th March, 2017.

Various observation and measurement have been taken during this period, they are as

follows:

Energy storage in form of heat offers a potential pathway for small (local) and large

(utility power plants) scale applications. Thermal storage systems provide a unique

opportunity to store energy locally in the form of heat that cannot be transported over

long distances. Current thermal storage systems are still in its infancy. The most

common ones are large, water-heating storage tanks and molten salt-based systems at

solar power plants. These systems have been designed based on the economics of

water and salt, the heat capacity of water, and the latent heat of salts. Research on a

large host of sensible heat storage and phase-change materials have been conducted

over the past two decades. The materials parameters that are relevant for this

application are: melting point, boiling point, vapor pressure, density, heat capacity,

thermal conductivity, latent heat of fusion and chemical reactivity.

While it is intuitive that increasing the temperature of storage could pack in more

energy, barriers to the development and deployment of high energy density storage

remain, including handling materials at high temperatures, associated systems costs,

and operating costs. Thus sensible thermal storage systems are cost prohibitive. Phase

change materials (PCM) do provide a viable economical solution for higher energy

storage density. However, operation temperatures limit current PCM systems; higher

temperatures cause chemical instability and reactivity with containers. Development

of affordable high-density thermal storage system will only be possible by utilizing

Ram Krishna Dharmarth Foundation University, Bhopal Page 86

Chapter-4 Experimental Data Analysis,
Results and Discussions

low cost earth abundant thermal storage materials in conjunction with suitable

thermally insulating container materials.

Current heat storage systems utilize either sensible heat storage (i.e. water in storage

tanks) or latent heat storage (i.e. phase-change materials such as molten salts). The

relatively low operating temperatures of these systems limit their capacity to store

thermal energy; storage systems with higher temperatures would be more economical.

In this project, we are developing an affordable high energy density thermal storage

system that can store heat at temperature around 1000 OC. The unique aspects of this

system are the selection of an alkali halide salt with high melting temperature and a

corrosion resistant cheap ceramic container material. The thermal storage unit will be

coupled with a high solar concentrator system (1000 – 10,000 x).

During 3 days of trial run from 11 May to 14 th May 2016, we have achieved a drop in

temperature at the middle of core to the tune of 2 to 2.5 oC per hour in 15 hours from

310oCto 278oC. The trial operations will continue for about 6 month to get study

steam flow at highest possible temperature and pressure to run the steam turbine for

Power generation to the tune of 300W electric (1000W thermal).

The temperature achieved at the tip of solar focal point about 1400oC. The

temperature at the core mid-point was found to be of the order of 310 oC which may be

sufficient to generate steam for heat transfer studies.

Ram Krishna Dharmarth Foundation University, Bhopal Page 87

Chapter-4 Experimental Data Analysis,
Results and Discussions

Fig. 4.17 Filling of salt at core of receiver

Ram Krishna Dharmarth Foundation University, Bhopal Page 88

Chapter-4 Experimental Data Analysis,
Results and Discussions

Fig. 4.18 Focus of lens at tip of receiver

Ram Krishna Dharmarth Foundation University, Bhopal Page 89

Chapter-4 Experimental Data Analysis,
Results and Discussions

Fig. 4.19 Temperature (max.) recorded during field test

Ram Krishna Dharmarth Foundation University, Bhopal Page 90

Chapter-4 Experimental Data Analysis,
Results and Discussions

Fig. 4.20 Salt heating and cooling cycle during lab test

Ram Krishna Dharmarth Foundation University, Bhopal Page 91

Chapter-4 Experimental Data Analysis,
Results and Discussions

Fig. 4.21 Steam output of system

Ram Krishna Dharmarth Foundation University, Bhopal Page 92

 CHAPTER-5 CONCLUSIONS
AND FUTURE SCOPE
5. GENERAL

Energy security, high efficiency with economy feasibility, sustainable development

with environmental protection are the globally primacy topics. In present era the

growth of population is very fast, resulting energy demand is also increasing

exponentially mainly due to their modern life style, etc. Therefore, renewable based

24×7 energy solutions have to be invented. Conventional renewable energy

generation systems have enormous issues i.e. uninterrupted supply, energy storage

with controlled GHGs emissions. Unlike conventional renewable approach, an

innovative passive hybrid approach is the coupling of energy storage system with

Concentrated Solar Power (CSP) system. By using solar energy, the hybrid system is

able to generate huge amount of energy. These systems are characterized by various

advantages i.e. appropriate efficiency, no emissions of GHGs with very low operation

and maintenance costs etc.

Two experimental set ups with objective to proficient exploitation solar energy and

store through solid storage systems to provide the power 24×7. A 1 MWe (3.5 MW

thermal) solar power plant with 16 hours thermal storage capacity and A 1 kWe high

energy density thermal energy storage for concentrated solar plant were experimented

and found satisfactory results as per Indian climatic conditions.

5.1 CONCLUSIONS FROM PERFORMANCE OF 1 MWe (3.5

MWh) SOLAR POWER PLANT WITH 16 HOURS THERMAL
STORAGE CAPACITY

The plant operates on Rankine cycle principle. The Parabolic Reflector concentrates

the solar radiation towards the in-house developed, highly efficient cavity receiver.

The cavity of the Receiver which is made of monolithic cast iron acts as perfect black
body and thus provides excellent thermal storage. The boiler grade coil around the

body acts as a heat exchanger which allows for water to exchange heat and convert

into steam.

The thermal storage can be operated between 250 oC to 550oC and can be discharged.

The steam generated is mostly super- heated steam and the rest is saturated steam to

pertaining pressure from 38 bar to 44 bar gauge pressure.

5.2 CONCLUSIONS FROM PERFORMANCE OF 1 kWe HIGH

ENERGY DENSITY THERMAL STORAGE

It was concluded from various readings that the temperature achieved at the tip of

solar focal point about 1400oC. The temperature at the core mid-point was found to be

of the order of 310oC which is sufficient to generate steam for heat transfer studies.

5.3 COMPARATIVE ANALYSIS OF SOLID

THERMAL STORAGE SYSTEM WITH OTHER
SYSTEMS

S.N. Parameter India One Mount MNRE R&D Project ,

abu Bhopal
Technical Parameter
1 Thermal Capacity 3.5 MWth 40 KWth
2 Electrical Capacity 1 MWe 10 kWe
3 Heat source(CSP 60 sq m parabolic 16 sq m parabolic
System) Scheffler dish Scheffler dish
4 Storage medium Cast Iron Halide Salt
4.1 Specific heat(KJ/Kg K) 2100 3500
4.2 Life (year) 25 35
4.3 Heat redundancy ( min) 6000 8000
4.4 Density (kg/m3) 120 80
4.5 chemical composition
4.6 Chemically activeness inert inert
4.7 Impact on Environment
5 Area (Acre) 8 4.5
5.4 FUTURE SCOPE

The long term aim of this research work is to develop the necessary technology know-

how to enable the manufacturing process in India for large scale MW systems.

Promote energy efficient concept of steam generation through solar thermal storage

and apply in Carbon Capture Sequestration (CCS) system, shown as Fig. 5.1.

Fig. 5.1 Steam generation through solar thermal storage and apply in CCS system
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scale, Molten salt solar thermal pilot facility: Plant description and
commissioning experiences, Renewable Energy, 2016; 99:852-866.
13. Gadhia D., Gadhia S., Parabolic solar concentrator for cooking, food
processing and other applications, http://www.solare-bruecke.org/ SCI
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Comprehensive Semiconductor Science and Technology, Elsevier, 2011; 3:36-
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crystals, 2010; US7641733. & Dutta PS., Apparatus for growth of single
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16. Fernandez-Garcia A., Zarza E., Valenzuela L., Parabolic-trough solar

collectors and their applications. Renew Sust Energy Rev, 2010; 14:1695-
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17. Zanganeh G., Pedretti A., Haselbacher A., Steinfeld A., Design of packed bed
thermal energy storage systems forhigh-temperature industrial process heat,
Applied Energy,2015;137:812-822.
18. Gharbi N., Derbal H., Bouaichaoui S., A comparative study between parabolic
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thermal plants: parabolic trough versus Fresnel, Journal of Solar Energy,
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23. Jayasimha BK., Fixed Focus Fully Tracked 60 SQM Paraboloid Dish with
Heat Storage. Sun Focus, 2014; 2(1):10-12.

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a Review of Thermal Storage options. International conference on Energy,
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25. Lappalainen J., Hakkarainena E., Sihvonenb T., Rodriguez-Garciac M.,

Alopaeusd V., Modeling a molten salt thermal energy system – A validation
study, Applied Energy, 2019; 126-145.
26. Kamimoto M., Investigation of nitrate salts for solar latent heat storage, Solar
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27. Mehos M., Turchi C., Vidal J., Wagner M., Ma Z., Ho C., Kolb W., Andraka
C., Kruizenga A., Concentrating Solar Power Gen 3 Demonstration Roadmap,
National Renewable Energy Laboratory, Golden, CO (United States), 2017;
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28. Busamante MJ., Developing a solar-bio hybrid energy generation system for
self-sustainable waste water treatment, Michigan State University, 2016.
29. Morin G., Dersch J., Platzer W., Comparison of linear Fresnel and parabolic
trough collector power plants, Solar Energy, 2012; 86:1-12.

30. Firdaus MS., Hawa SAB., Roberto RI., Scott MG., Mirror symmetrical
dielectric totally internally reflecting concentrator for building integrated
photovoltaic systems, Applied Energy, 2014; 113:32-40.

31. Breidenbacha N., Martinb C., Jockenhöferb H., Bauerc T., Thermal energy
storage in molten alts: Overview of novel concepts and the DLR test facility
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Germany, 2016; 15-17.
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Renewable Energy Research Conference, Energy Procedia, 2014; 58:152 –
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33. Powell K., Rashid K., Ellingwood K., Tuttle J., Iverson B., Hybrid
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34. Purohit I., Purohit P., Technical and economic potential of concentrating solar
thermal power generation in India. Renewable and Sustainable Energy
Reviews, 2017; 78:648-667.
35. Duggal R., Jitle R., Numerical Investigation on Trapezoidal Cavity Receiver
Used In LFR with Water Flow in Absorber Tubes, IOP Conference Material
Science and Engineering, 2017; 187:1-7.
36. Khare S., DellAmico M., Knight C., McGarry S., Selection of material for
high temperature sensible energy storage, Solar Energy Materials and Solar
Cells, 2013; 115:114-122.
37. Kuravi S., Goswami DY., Stefanakos E., Thermal Energy Storage for
Concentrating Solar Power Plants, Technology and Innovation, 2012;
14(2):81-91.
38. Relloso S., Lata J., Molten salt thermal storage: A proven solution to increase
plant dispatchability experience in Gemasolar tower plant, Proceedings of the
17th International Solar Paces Conference, Granada, 2011.
39. Muller SC., Sandner PG., Welpe IM., Monitoring innovation in electro-
chemical energy storage technologies: A patent –based approach, Applied
Energy, 2015; 137:537-44.
40. Soni SK., Pandey M., Bartaria VN., Ground coupled heat exchangers: A
review and applications, Renewable and sustainable energy reviews, 2015;
47:83-92.
41. Soni SK., Pandey M., Bartaria VN., Hybrid ground coupled heat exchanger
systems for space heating/cooling applications: A review, Renewable and
sustainable energy reviews, 2016; 60:724-38.

42. Sethi VK., Vyas S., An Innovative Approach for Carbon Capture &
Sequestration on a Thermal power plant through conversion to multi-purpose
fuels – A feasibility study in Indian context. Science Direct, Energy Procedia,
2017; 114:1288-1296.

43. Lee T., Lim S., Shin S., Sadowski DL., Numerical simulation of particulate
flow in interconnected porous media for central particle-heating receiver
applications, Solar Energy, 2015; 113:20-28.

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44. Cooper T., Dahler F., Ambrosetti G., Predretti A., Steinfeld A., Performance
of compound parabolic concentrators with polygonal apertures, Solar Energy,
2013; 95:308-3018.

45. Tamaura Y., CL-CSP Technology for Replacement of Coal in the Power
Plants, ICORE, 2014; 12:8-9.

46. Tamaura Y., Shigeta S., Meng QL., Aiba T., Kikura H., Cross linear solar
concentration system for CSP and CPV. Energy Procedia, 2014; 49:249-256.

47. Thirugnanasambandam M., Iniyan, S., Goic R., A review of solar thermal
technologies.Renewable and Sustainable, Energy Reviews, 2010; 14(1):312-
322.
48. Herrmann U., Kelly B., Price H., Two-tank molten salt storage for parabolic
trough solar power plants, Energy, 2004; 29:883-93.
49. Luo X., Wang J., Dooner M., Clake J., Overview of current development in
electrical energy storage technologies and the application potential in power
system operation, Applied Energy, 2015; 137:511-536.
50. Ma Z., Glatzmaier GC., Mehos M., Development of solid particle thermal
energy storage for concentrating solar power plants that use fluidized bed
technology, Energy Procedia, 2014; 49:898-907.
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absorber thin film structure based on double TiN xOy layer for concentrated
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Ram Krishna Dharmarth Foundation University, Bhopal Page 100

LIST OF PUBLICATIONS
 Publications

PUBLICATIONS

International journals

(1) Anil Kumar, V K Sethi, Suresh Kumar Soni & Sachin Tiwari, “Energy

Storage Technologies- An Overview”, International Journal of Science,

Engineering and Technology Research (IJSETR) Volume 9, Issue 5, May

2020.

(2) Anil Kumar, Prashant Mishra, Suresh Kumar Soni, V K Sethi, Sachin Tiwari,

“Future of Concentrated Solar Power in India Coupled with 24×7 Thermal

Storage”. International Journal on Emerging Technologies (Scopus)- Accepted

(3) Anil Kumar,V K Sethi, Suresh Kumar Soni & Sachin Tiwari “Study on

Future of Solar Thermal Storage System Using Concentrated Solar Power”.

International Journal of Innovative Engineering Research (IJIER) Volume 1,

Issue 6, June 2020.

International Conferences

1. Anil Kumar, V K Sethi, Solar Thermal Plants Coupled with a Thermal

Storage-A Review of Thermal Storage Options, International Conference on

Energy, Environment and Economics, August 14-16, 2018.

Ram Krishna Dharmarth Foundation University, Bhopal Page 101

 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 9, Issue 5, May 2020, ISSN: 2278 -7798

Energy Storage Technologies- An Overview

Anil Kumar1, V K Sethi2, Suresh Ku Soni3Sachin Tiwari4
1, 2
RKDF University, Bhopal
3
S. V. Polytechnic, Bhopal
4
Lakshmi Narain College of Technology

Abstract-Rapidlyrising demand of energy, fast depleting

becomes a prerequisite for using renewable energy
and limited stock of fossil fuels, their serious
[2,3]. Energy storage systems play pivotal role
environmental issues compel to shift towards to more use
towards smooth and continuous energy supply.
of renewable energy sources.There are some critical issues
Energy storage systemholdsthe generated energyfor a
while using renewable energy sources like reliability,
short time and supplied it according to need.
quality, etc. Energy storage systems have the capability to

solve the problems up to some extent towards smooth and Therefore, energy storage system is the most capable

continuous energy supply. Paper presents brief overview of technology to meet the rising demand of energy. A

various energy storage systems. device that accumulates energy is sometimes termed

as an accumulator. There are various energy storage

Keywords-Energy storage; Renewable energy.
systems. Paper presents brief overview of various
I. INTRODUCTION
energy storage systems.
Due to rapid growth in infrastructure sector (i.e.
II. ENERGY STORAGE SYSTEMS (ESSs)
communication, transport, road and rail networks,

etc.),demand of energy is rising enormously and Many researches come on the conclusion that
more than 20-30% demand is satisfied by non- renewable energy sources are the only option for
conventional energy sources [1]. Renewable or non- sustainable development and appropriate energy
conventional energy sources are essential for the storage systems are the prerequisite. They have
sustainable development, have many advantagesover feature to store the energy and then release as and
conventional energy sources like availability, when required.Some ESSs are flywheel energy
environment friendly, etc. But the most important storage, compressed air energy storage, pumped
difficultyis theunevengeneration of energy.Therefore, storage, batteries, regenerative fuel cell storage,
trustworthy and affordable energy storage system superconducting magnet energy storage, etc.

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All Rights Reserved © 2020 IJSETR
 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 9, Issue 5, May 2020, ISSN: 2278 -7798

A. Flywheel energy storage system

Flywheel energy storage systems store energy

mechanically in the flywheel rotor by rotating the

rotor. Afterward generator is employed to convert

mechanical energy to electrical, as shown in Fig. 1. It

is efficient and used for various applications. It is

Fig. 2. Compressed air energy storage
preferred due to compactness, light in weight and
C. Pumped storage
high energy capacity. But due to limited amount of

charge/discharge cycle characteristic, it is not cost- In pumped storage system, water is pumped and
effective. stored at height during off-peak periodsthen utilized

to generate electricity to meet the peak demand, as

shown in Fig. 3. Hydro power plants store electricity

in Megawatts (MW) or Gigawatts(GW). It has

many advantages i.e. fast start-up, reliable but

requires large area and cost.

Fig. 1.Flywheel energy storage system

B. Compressed air energy storage

It is also known as stone storage system. Air is

compressed to absorb and store heat energy after that

released to utilized to generate steam and electricity.

Fig. 3. Pumped storage
Conceptual diagram is shown as Fig. 2. It is getting D. Battery
popularity due to quick start-up, able to integrate with
Basic construction, working principle, functions of
other energy sources but requires geological structure
battery is very familiar, as shown in Fig. 4 (a) and
reliance [5].
(b).Portable batteries are well accepted in many small

storage applications like transport sector, utilities, etc.

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 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 9, Issue 5, May 2020, ISSN: 2278 -7798

But it has some drawbacks like high cost, short life disadvantages like facing difficulty in storing of
and regular maintenance. hydrogen due to highly inflammable nature of H 2 and

requirement of high capital cost due to platinum

catalyst.

(a)

Fig. 5.Hydrogen fuel cell

F. Under-ground thermal energy storage

Temperature of underground (i.e. below 2-3m)

remains constant round the year [7,8]. Using methods

(b) of ground coupled heat exchange systems(i.e. Earth
Fig. 4. Battery
Air Heat Exchange (EAHE), as shown in Fig. 6,
E. Regenerative fuel cell storage
ground source heat pumps), natural heating/cooling

It is electrochemical cell, converts source fuel (i.e. air/liquid could be done.

hydrogen, methane, propane, methanol, etc.) into Fresh Air

electricity. Hydrogen fuel cell is the one type of

Air Blower Room
electrochemical cell, where hydrogen is used the Ground Level

primary fuel and oxygen is also required, as shown in

Fig. 5. They produce electricity with very little

pollution like hydrogen cell produces by product

water. It has many advantages like no green house

Fig. 6.Earth air heat exchanger
gases, more operating time [6]. But has some

119
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 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 9, Issue 5, May 2020, ISSN: 2278 -7798

applications [9,10]. A closer look at the capital

G. Superconducting magnet energy storage
cost distribution of two-tank

This is an advanced energy storage system. It stores storage systems, reveals that indirect systems

energy in the magnetic field within magnets that is with a maximum operating temperature of 400

developed by flow of direct current in a °C have differing heattransfer fluids (HTF) and

superconducting coil, and then releases it within storage media. For those systems, the molten salt

fraction of cycle, as shown in Fig.7. storage media (about 35 % of the direct

capital costs) and the storage tanks (about 24 %

of the direct capital costs) are the main bearers

of cost. For directsystems with operating

temperatures up to 560 °C, using molten salt as

the HTF and the storage media, the capital

cost ratios are 34 % for the storage media and 31

% for the storage tank, respectively [11]

Fig. 7.Superconducting magnet energy storage

H. Molten salt

Molten salt storage systems are the established

commercially available concept for solar

thermal power plants. Due to their low vapor

pressure and comparatively high thermal

I. Stone Storage
stability, molten salts are
In this type of energy storage medium is pebbles that
preferred as the heat transfer fluid and storage has significantly higher thermal

medium. However, due to pricing pressure, the conductivity than normal concrete. Although the

development of alternative, more cost-effective recipe of this material is quite complex the main

component is quartzite, a
concepts is an important step in making thermal
natural geo-material readily available in many parts of
energy storage more competitive for
the world. Further, heat is transported in and out of
industrial processes and solar thermal
the storage by way of a

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 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 9, Issue 5, May 2020, ISSN: 2278 -7798

heat transfer fluid (HTF) which flows through steel

REFERENCES
pipe heat exchangers that are cast into concrete
1. A. Ummadisingu, M.S.Soni,“Concentrating solar
storage elements. These
power-Technology, potential and policy in
elements are specially designed to deal with thermal
India”,Renewable and Sustainable Energy Reviews
deformations and stressing[12,13]
2011;15:5169-75.

2. M. Kamimoto,“Investigation of nitrate salts for solar

latent heat storage”, Solar Energy 1980;24:581-87.

3. Z. Ma, G.C. Glatzmaier, M, Mehos, “ Development of

solid particle thermal energy storage for concentrating

solar power plants that use fluidized bed

technology”,Energy Procedia 2014;49:898-907.

4. X. Luo, J. Wang, M.Dooner, J. Clake, “Overview of

current development in electrical energy storage

technologies and the application potential in power

system operation”,Applied Energy 2015;137:511-36.

5. H. Sun, X. Luo,J. Wang, “Feasibility study of a hybrid

wind turbine system-Integration with compressed air

Stone storage may be a good technology for CL-CSP
energy storage”, Applied Energy 2015;137:617-28.
system. 6. S.C. Muller, P.G.Sandner, I.M.Welpe,“Monitoring

innovation in electro-chemical energy storage

III. CONCLUSION
technologies: A patent –based approach”, Applied

Energy 2015;137:537-44.
It can be concluded from comparative study of
7. S.K. Soni,M. Pandey, V.N.Bartaria,“Ground coupled
various energy storage systems that for the need of
heat exchangers: A review and applications”,

large scale energy storage underground thermal, Renewable and sustainable energy reviews2015;47:83-

pumped hydro and compressed air energy 92.

8. S.K. Soni, M. Pandey, V.N. Bartaria, “Hybrid ground

storagesystems are suitable. Superconductors are able
coupled heat exchanger systems for space
to store energy with negligible losses. Fuel cells are a
heating/cooling applications: A review”, Renewable

viable alternative to petrol engines due to their high and sustainable energy reviews2016;60:724-38.

efficiency.Flywheels have a narrow range and 9. Herrmann U, Kelly B, and Price H. Two-tank molten

salt storage for parabolic trough solar power plants.

suitable for small scale operations.
Energy, vol. 29, no. 5–6, 2004, pp. 883–

893.

121
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 International Journal of Science, Engineering and Technology Research (IJSETR)
Volume 9, Issue 5, May 2020, ISSN: 2278 -7798

10. Relloso S and Lata J. Molten Salt Thermal Storage: A

12. Pål G. Bergana,, Christopher J. Greiner “A new type of
Proven Solution to increase Plant Dispatchability.
large scale thermal energy storage” Renewable Energy
Experience in Gemasolar Tower
Research Conference, RERC 2014
Plant. Solar Paces, 2011.
13. G. Zanganeh , A. Pedretti , A. Haselbacher , A.
11. Nils Breidenbacha, Claudia Martinb, Henning
Steinfeld “Design of packed bed thermal energy storage
Jockenhöferb, Thomas Bauerc “Thermal Energy
systems for high-temperature industrial process heat”
Storage In Molten Salts: Overview Of Novel
Applied Energy 137 (2015) 812–822
Concepts And The DLR Test Facility TESIS” 10th

International Renewable Energy Storage Conference,

IRES 2016, 15-17 March 2016,

Düsseldorf, Germany

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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
Vol 1, Issue 6, June 2020

Study On Future of Solar Thermal Storage System

Using Concentrated Solar Power
Anil Kumar1, V K Sethi2, Suresh Ku Soni3 Sachin Tiwari4
1, 2
RKDF University, Bhopal
3
S. V. Polytechnic, Bhopal
4
Lakshmi Narain College of Technology

Abstract— The increase in demand for electric power all

around the world due to proliferation in population has crucial
impact on environment. This concern leads to question to
human knowledge. The pioneered engineering delivered for a
new concept of worlds electric demand with higher potential
with the existing power plant. One of the new ways is Solar
photovoltaic (PV). But Solar PV has limitations of sun and
available area, which is a major concern. Such undistinguished
concerns related with Solar PV can be resolved using solar
concentrated power. The other way is to use solar thermal
storage system, which solves the issue of problem of power
supply, when sun is not available. The objective of this paper is
to give an overview of solar thermal storage system using
concentrated solar power.

Keywords— Parabolic trough collector, Linear Fresnel

reflector, Central receiver tower, Parabolic dish
Fig. 1. Schematic of parabolic trough collector and parabolic trough
I. INTRODUCTION reflector
The classification of CSP technologies is performed
using concentration technique. Based on the field data Linear Fresnel reflector (LFR) is having game
various CSP plants are required. Four types of CSP plans of the intelligent glass strips, at the base of the
technologies are used in India to generate power. framework, turning around an autonomous parallel pivot
(Fig. 2). These strips center around a raised direct collector,
In 1980s, a based line center innovation based CSP which further moves the warmth to the HTF. At first, it was
appeared which was known as Parabolic trough gatherer proposed as an option of focal collector tower framework,
(PTC). Developed of PTC is performed wy utilizing an yet it was not unreasonably much productive because of the
explanatory trough shape gatherer and it is upheld utilizing a warmth misfortunes related with one pivot following
straightforward platform. PTC focuses the bar radiation on framework. As of late it can supplant the allegorical gatherer
its central line, where collectors prepared to retain. The as it has a few focal points of low capital expense and with
beneficiary is covered with high absorbance material and is no revolute joints. Its exergy proficiency is exceptionally
encompassed by the glass cylinder to decrease the near that of explanatory trough gatherer for an immediate
convective misfortune by making a vacuum in the middle of steam age (DSG). The information gathered from NREL [2]
the glass cylinder and recipient (Figs. 1). The vacuum has a for the current CSP power plant with various advances are
noteworthy job in the protection of recipient and because of appeared in Table1. This information demonstrates that LFR
a slight loss of vacuum, heat misfortune may build multiple has the capability of producing more power in a relatively
times. Spillage in a vacuum can be limited by conservative littler catchment. Theater-push concealing, and blocking
plan with a lesser number of parts and spillage free glass brings about some piece of the reflector being unused.
spread[1]. Cosine impact, neatness, reflectivity, the absorptivity of the
cylinder, the transmissivity of the recipient spread and other
warm misfortunes, expands the levelized cost of vitality of
LFR. Some new structure of semi-illustrative LFR sunlight-
based concentrator proposed by analysts dispenses with the
misfortunes of concealing and obstructing between two
adjoining layers. LFR additionally has the capacity of liquid
salts based warm capacity as the working temperature of
LFR can reach up to 550 °C with liquid nitrate (liquid
nitrates contained in liquid salts) as warmth move liquid.

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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
Vol 1, Issue 6, June 2020

based warm control. The temperature scope of the PDC

fluctuates from 400 °C to 750 °C with a fixation proportion
more than 3000 and warm proficiency 23%. PDC is the
promising innovation for little scale control age and could
be an ideal innovation to supplant the DG sets. Allegorical
dish innovation is additionally a piece of disseminated sun
powered power age, which can lessen the heap on
concentrated power plants. Illustrative dish concentrator is
utilized to produce power utilizing dish Stirling motor
innovation also [4]. Dish Stirling motor is having
demonstrated effectiveness around 30%, with measured
quality comprising of development Stirling converter.
Progressed Stirling converter is a kind of straight alternator
to create power from the responding movement legitimately.
It is valuable to take out mechanical transmission
Fig. 2. Linear Fresnel reflector
misfortunes in the Stirling motor particularly with a free
cylinder Stirling motor, which have the points of interest
Focal recipient tower innovation, otherwise called
with a direct alternator. From the current refreshed
sun-oriented pinnacle innovation, is a point center kind of
innovation, it is seen that the dish free cylinder Stirling
sunlight based warm power age innovation. It comprises of
motor (FPSE) joined with bio-fuel can firmly, supplant DG
numerous heliostats, which are having double pivot control
sets and has the capacity to be autonomous of the lattice
and having the plan to concentrate on the stationary
influence supply.
collector (Fig. 3). The stationary beneficiary is capable to
assimilate the concentrated radiation from various heliostats.
Another capacity of beneficiaries is to move the warmth
from assimilated radiation to the warmth move liquid
(HTF), and therefore, HTF moves the vitality to the power
cycle liquid. A power cycle is commonly founded on the
Rankine cycle for warm power plants, and for some
situation, the HTF itself could be utilized as a working
liquid. It very well may be distinctive for the high limit and
capacity-based framework. Collector configuration differs
from full hole type to completely outside sort, which uses
cylinders to retain the concentrated sun-oriented vitality [3].
The warmth is then moved to the HTF, contained in the
cylinders to the power cycle. Spain with 2300 MW
introduced limit, is the world head in the CSP innovation
utilizing sun powered pinnacle innovation.

Fig. 4. Parabolic dish existing at ANU and CAD image [5]

Fig. 3. Solar tower technology with heliostats field

II. CLASSIFICATIONS OF THERMAL ENERGY STORAGE
SYSTEM FOR CONCENTRATED SOLAR POWER APPLICATIONS
Allegorical dish concentrators are point center sort The major objective of the SLAG project is to eliminate the
gadgets, comprising of two noteworthy parts for example constraints associated with existing storage technologies for
illustrative reflector (dish) and a sun powered warm Concentrated Solar Power applications. In this section two
beneficiary set at the point of convergence (Fig. 4). different Thermal Energy Storage (TES) concepts are
Illustrative dish has a high-temperature application, possibly validated for defining a novel storage system with new
valuable for the sun oriented warm steam age and sunlight fluids and materials for facilitating the integration of
renewable energy systems into the utility grid [6].

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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
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A. Air TES as heat transfer fluid (HTF)

In order to achieve potential reduction in costs, slag, which
is considered as a waste material in steel industries is used
as an inventory for TES of CSP. To successfully introduce
this technology into market, the need for unscalable and
efficient TES solutions is a basic prerequisite. In addition,
queries regarding the execution of large installations in
combination with slag-pebbles as inventory needs to be Fig. 7. Test bed at DLR Germany
investigated [7]. In order to accommodate this solution, a B. Molten Salt TES as heat transfer fluid (HTF)
European project REslag is devoted to this.
The major aspect of this technology is that, it replaces low
cost steel slag with molten salt in order to achieve more
cost- effective solutions. Here, the pilot deals with
developing a storage tank which can operate at an approx.
300-560ºC molten salt temperature range. In this condition
the molten salt acts as an energy storage material[1][8].

Fig. 5. Method of thermal energy storage (TES) of CSP

The activities that needs to be carried for developing this

system are discussed as follows: Initially, the design of TES
was conceptualized. Then the thermal analysis is performed
on the TES. Further, Pilot-scale tests were performed on the Fig. 8. Flow diagram of molten salt as heat transfer fluid (HTF)
slag pebbles setup and different insulation options and
different distributors are used to simulate the flow The pilot discussed is executed at ENEA Casaccia Research
distribution. Finally, the thermo-mechanical calculations are Centre’s (Italy) concentrated solar power plant [4], [8], [9].
carried out for the container wall and the slag pebbles.
1. Heating water: Water can be warmed for either
residential or institutional purposes for use in spots
like residences or medical clinics. This may
incorporate boiling water for cooking, washing,
cleaning, and that's only the tip of the iceberg.
While this is maybe the most natural use, it is
ostensibly one of the most significant applications,
and the reserve funds are effectively determined –
the expense of warming water by utilization of an
elective vitality source.

Fig. 6. Fluid Temperature vs Time graph

2. Industrial processes: High temp water can
likewise be utilized to clean modern hardware and
At DLR Germany, Based on the existing test bed, a concept apparatus. A few areas, including drink packaging
demonstrator pilot is developed for high-temperature plants, for instance, require exceptionally huge
storage. amounts of heated water for both creation and
upkeep. Steam can likewise be created by utilizing
a pressurized warmth exchanger that will enable
the water to be warmed above 100⁰C. Once more,
the investment funds is in the shirking of the
expense of warming the water or steam [10].

3. Cooling: Retention chilling can be utilized for

nourishment refrigeration (which will keep up a
temperature of around 4 - 7 degrees Celsius). In
numerous zones of the world including India and
the vast majority of sub-Saharan Africa,

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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
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refrigeration is

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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
Vol 1, Issue 6, June 2020

a genuine distinct advantage. It enables ladies to III. RESULT AND DISCUSSION

work outside of the home and not need to get ready
dinners without any preparation every day. A. Solar Observation
Refrigeration can likewise be utilized for drug. For the purpose of testing solar observation (𝛿), a one
year of data is considered. Solar observation can be
4. Agriculture: Greenhouse plants and harvests can calculated by
𝛿(𝑖𝑛 𝑑𝑒𝑔𝑟𝑒𝑒) = 23.45sin [ (284 + 𝑛)],
profit by the warmth during the evening and 360

365
cooling during the day to keep up a set temperature (1)

Where 𝑛 is no. of days with considering n equal to one

consistently. Extra, the CO2 created by the burning
of biogas or other fuel to deliver control during the
evening can be ducted to the nursery to enable the on first January.
plants to develop [11]. The data obtained is plotted in the graph below

5. Accelerating biogas production: Biogas preparing

is increasingly proficient with higher temperatures.
Optional warmth can be utilized to accelerate the
procedure of the processing tank transforming
waste into fuel. This is critical in light of the fact
that the biogas can rapidly turn into its very own
wellspring of inexhaustible power or heat or be
additionally prepared to give a wellspring of
sustainable fuel.

6. Space heating or cooling: Obviously, the free heat

vitality can likewise be utilized for space warming
in homes, processing plants, residences, emergency

cos 𝜔 = − tan ∅ tan 𝛿

Fig. 9. The graph is plotted from 21-Dec to 21 Dec (for 365 days)
clinics, and so on. On the other hand, with the
utilization of ingestion chillers, a similar warmth (2)

cos 𝜃 = sin 𝛿 sin(∅ − 𝛽) + cos 𝛿 cos 𝜔 cos(∅

can give cooling [12].

7. Generate even more electricity: On the off − 𝛽)

chance that electricity is required and there are no (3)
Where 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑧𝑖𝑚𝑢𝑡ℎ 𝑎𝑛𝑔𝑙𝑒(𝛾): Is zero
utilizations for the thermal energy for warming or
cooling, a Rankine cycle turbine (which can utilize
lower temperature warmth to create control) can be because

𝑠𝑙𝑜𝑝𝑒 𝑎𝑛𝑔𝑙𝑒(𝛽): It is 30֯ because the panel mounted on

utilized to expand the power yield of the in general inclined surface is the facing due south
sun-based arrangement.
of solar e-vehicle. 𝛿 = 𝑑𝑒𝑐𝑙𝑖𝑛𝑎𝑡𝑖𝑜𝑛 𝑎𝑛𝑔𝑙𝑒 , 𝛾
roof

=
𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑧𝑖𝑚𝑢𝑡ℎ 𝑎𝑛𝑔𝑙𝑒, 𝛽=
𝑠𝑙𝑜𝑝𝑒 𝑎𝑛𝑔𝑙𝑒 , 𝜃 =
𝑎𝑛𝑔𝑙𝑒 𝑜𝑓 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 ,∅ = 𝑙𝑎𝑡𝑖𝑡𝑢𝑑𝑒 𝑎𝑛𝑔𝑙𝑒
(+90 −
𝑁𝐻 𝑡𝑜 − 90 𝑆𝐻), 𝜔 = ℎ𝑜𝑢𝑟 𝑎𝑛𝑔𝑙𝑒
On the base of equation 2 and 3 further data can be
calculated which is presented in Table 1

TABLE I. SOLAR OBSERVATION DATA

Avg. Month Date 𝖰 𝜽 ∅ 𝑚

1 17 January -20.917 0 30 78.79191 23.3103 80.52113957
2 16 February -12.9546 0 30 82.98946 23.3103 84.31165897
3 16 March -2.41773 0 30 88.68396 23.3103 88.95756733
4 15 April 9.414893 0 30 95.10958 23.3103 94.09710186
5 15 May 15.51533 0 30 100.1009 23.3103 98.43087465
6 11 June 21.75085 0 30 102.3264 23.3103 100.583086
7 17 July 22.79617 0 30 101.3463 23.3103 99.61266702
8 16 August 17.10812 0 30 97.27783 23.3103 95.91697567
9 15 September 2.216887 0 30 91.20675 23.3103 90.95573605
10 15 October -5.40067 0 30 84.79095 23.3103 85.82095551
11 14 November -15.6661 0 30 79.83631 23.3103 81.51073843
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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
Vol 1, Issue 6, June 2020
12 10 December -21.6746 0 30 77.69219 23.3103 79.43570225

B. Error Calculation for Time Correction 𝐸 = 229.18(0.000075 + 0.001868

cos 𝐵 −
0.032077 sin 𝐵 − 0.014615 cos 2𝐵
It is required to calculate the error of the system in order

−
to correct the orientation for later use.

0.04089 sin 2𝐵) (4)

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 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
Vol 1, Issue 6, June 2020

𝐵
360= (𝑛 − 1) 𝑎 = −0.309 + 0.539 cos ∅ − + 0.290 (
𝑆
)
0.0693𝐸
(5)
365 𝐿
𝑆𝑚 𝑎𝑥

𝑺𝒎 = 15 𝜔
2 (7)
(6)
𝒂𝒙
𝑏 = 1.527 − 1.027 cos ∅ + 0.0926𝐸 − 0.359 (
)
𝑆

𝐿
Where, Height from sea level (EL) =527 m 𝑆𝑚 𝑎𝑥
(8)

𝑆̅ ̅
TABLE II. SOLAR ERROR DATA

S no. Avg. Month Date Sunrise (HH: Sunset (HH Error 𝑆(HH:MM
MM) MM) (HH:M )
M) ideal corrected
1 17 January 8:15 19:00 10.75 -9.32914 10.59451
2 16 February 8:00 19:15 11.25 -14.2409 11.01265
3 16 March 7:45 19:30 11.75 -9.35529 11.59408
4 15 April 7:15 19:45 12.5 -0.23641 12.49606
5 15 May 6:45 20:00 13.25 3.937088 13.08438
6 11 June 6:45 20:15 13.5 0.80629 13.38656
7 17 July 7:00 20:15 13.25 -6.00869 13.14986
8 16 August 7:00 20:00 13.00 -4.68858 12.62186
9 15 September 7:15 19:30 12.25 4.641625 12.11264
10 15 October 7:15 19:15 12.00 14.41014 11.25983
11 14 November 7:45 18:45 11.00 15.32706 10.74455
12 10 December 8:00 18:30 10.50 7.137699 10.38104

C. Monthly Average Daily Global Radiation

IV. CONCLUSION
Following equations are used for calculating Monthly global
In this paper an overview regarding the concentration
= 𝑎 + 𝑏 (𝑆 )
̅𝐻̅𝑔̅ ̅
Average
based solar energy application is provided. Different Heat
(9)
̅𝐻̅𝑐 ̅𝑆̅𝑚̅̅̅𝑎̅𝑥
Trapping technique are discussed in detail. Many different
characteristics such as solar observation, error calculation and
where 𝐻̅̅̅𝑔̅ and ̅𝐻̅𝑐̅ depict the daily global radiation Monthly global radiation is discussed in brief. The result show
on a variation in different parameters with respect to month of

normal and a clear day respectively (KJ/m2-day). 𝑆̅ is

horizontal surface per month for a particular location on a implementation.

̅𝑆̅𝑚̅𝑎̅𝑥̅
the average of the sunshine hours per day at a location and REFERENCES

corresponds to the maximum possible sunshine hours per [1] P. Systems, “Review on Solar Thermal Power Concentrators,”
day vol. 1, no. 3, 2017.
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Analysis,” Entropy, vol. 20, no. 8, p. 597, 2018.
and b are the constants obtained by fitting data
̅𝐻̅𝑔̅
̅̅̅̅̅̅̅̅ 𝑆
=𝑎+ 𝑏𝑚𝑎𝑥 ( )
̅̅̅
[3] E. Gholamalizadeh and J. A. E. D. Chung, “Design of the Collector

𝐻𝑜 𝑆 of a Solar Dish-Stirling System : A Case Study,” vol. 5, 2017.

̅𝐻̅𝑜̅ = Monthly average of daily extraterrestrial radiation on

[4] Y. Tamaura, S. Shigeta, Q. Meng, T. Aiba, and H. Kikura, “Cross
linear solar concentration system for CSP and CPV,” Energy
Procedia, vol. 49, pp. 249–256, 2014.
a [5] K. Lovegrove, “A new 500m2 paraboloidal dish solar

̅̅̅ (1 + 0.033 cos ) (𝜔 sin ∅

360𝑛
horizontal surface at the same location on a day (KJ/m2-day)
12

𝐻 =
concentrator,” no. September, 2009.

sin 𝛿 +
𝑂
[6] B. Stutz et al., “Comptes Rendus Physique Storage of thermal
𝑆𝐶 𝜋 solar energy Stockage thermique de l ’ énergie solaire,”
365
cos ∅ cos 𝛿 sin 𝜔
Comptes
(11) Rendus Phys., vol. 18, no. 7–8, pp. 401–414, 2017.

𝐾̅
[7] D. System, “Exergy Analysis of a Pilot Parabolic Solar,” pp. 1–12,

=
2017.
𝑇 ̅𝐻̅𝑔̅
(12) [8] H. Kikura, K. Kanatani, A. Hamdani, and Y. Tamaura,
̅
𝐻̅ ̅
𝑜
̅𝐻̅
̅𝐻̅ ̅𝐻̅ 2 ̅𝐻̅ 3
𝑑
= 1.390 − 4.027 [ 𝑔
]+ 5.531 [ 𝑔
]
“Fundamental Study of Cross Linear Concentration System and

7
 International Journal of Innovative Engineering Research (E-ISSN: 2349-882X)
Vol 1, Issue 6, June 2020
− 3.108 [ 𝑔
]
̅𝐻̅ ̅𝐻̅ ̅𝐻̅ ̅
Solar Power System in Tokyo Tech Fundamental Study of Cross

𝑜̅ 𝑜̅ 𝑜̅
Linear Concentration System and Solar Power System in Tokyo
�
Tech,” no. June, pp. 6–10, 2017.
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�
𝑜

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̅𝐻̅𝑑̅ (13)
3.108[𝐾̅ ]3
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̅𝐻̅ 𝑇 𝑇 𝑇
𝑜̅
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8
 Solar Thermal Plants coupled with a Thermal Storage – A Review
of Thermal Storage options
Anil Kumara, Vinod Krishna Sethi*b
a
MNRE, Delhi, India
b
RKDF University, Bhopal, India
*
Corresponding author’s mail: vksethi1949@gmail.com

Abstract

Storage technologies have been reviewed to establish indicative characterizations of energy density, conversion efficiency,
charge/discharge rates and costing. Research Development and Design (RD&D) is to be focused on various components of solar
thermal system viz. heliostats, tracking mechanism, tower structure, receiver and storage medium. The Objective of this paper is
to examine performance evaluation of 60 m 2 disc and Cast Iron receivers as thermal storage with direct steam production on a 1
MW plant at Mt. Abu. Other options of thermal storage like an innovative Halide Salt at MNRE sponsored RKDF- RPI, Indo-US
project and Rock storage for a 30 kW, MNRE sponsored Cross Linear Concentrated Solar Plant (CL- CSP) project at the State
Technological University, RGPV, in Central India are also examined. Accordingly promising research directions are proposed in
selection of high energy density Thermal Energy Storage using solid path-way option for higher storage temperature in excess of
600oC.

Keywords:Concentrated Solar Plant; Cross Linear Concentrated Solar Plant;Thermal Energy Storage;RGPV; RKDF; RPI

1. Introduction various solar thermal plants with storage technologies and to

survey the most appropriate optimization techniques to
The augmentation of low carbon technologies is being pursued in
determine optimal operation and size of storage of a system to
mission mode by the Indian Ministry of New & Renewable Energy
(MNRE) through accelerated pace of setting up of 100 GW Solar operate in distributed generation mode. A comparative Study
plants by 2022 as India‟s INDC, as per Paris Agreement (COP-21). of Thermal Energy Storage (TES) Technology in various
In the Energy sector the options such as the increased use of projects is carried out with an objective of achieving high
renewable energy, improved energy efficiency, adoption of Clean energy density of storage material capable of retaining heat at
Coal Technologies like Supercritical Plants, Integrated Gasification elevated temperatures.
Combined Cycle and Carbon Capture & Sequestration etc. will pave Within the research portfolio of the Solar Thermal Projects,
way for mitigation of climate change. Solar power generations is an the three technology pathways which hold promise for
important component which produces power through solar PV and achieving storage of heat at high temperatures can be
Solar thermal mode but these power are non-uniform and depend on
continuous solar radiations. A new program of 24 x7 “Power to All”
categorized by the phases of matter of the materials used;
has been launched by Ministry of Power that aims to provide un- liquid, solid, and gaseous. These are:
interrupted power supply. There are various remote locations where  A liquid pathway is considered to look much like
decentralized power requirement is very much required as reaching today‟s molten salt two tank tower configuration, but
of grid is not techno-commercially feasible. Therefore, de- using a suitable high temperature and cost effective
centralized renewable power plant is certainly needed which can Heat Transfer Fluid / Thermal Energy Storage.
produce clean energy 24 x7. Solar PV with battery storage could be  Solid pathways involve solid inert media which
possible but there is large opportunity for solar thermal power plant absorbs solar radiation and stores that energy as heat.
along with thermal storage in high Direct Normal Incidence (DNI)
When electric power is needed, the turbine working
radiations areas.
fluid is heated by the solid media.
The proliferation of non-scheduled generation from renewable  Gaseous pathways use an inert gas flowing through a
electrical energy sources such concentrated solar power (CSP) receiver to absorb the solar energy and then transfer
presents a need for enabling scheduled generation by the thermal energy to a storage system and / or the
incorporating energy storage; either via directly coupled turbine working fluid. The distinctive characteristic
Thermal Energy Storage (TES) or Electrical Storage Systems of inert gas systems is that the thermal energy is
(ESS) distributed within the electrical network or grid. The stored in a media that is not the fluid flowing in the
challenges for 100% renewable energy generation are to receiver.
minimize capitalization cost and to maximize energy dispatch The three Projects examined by us are contemplating to
capacity. The aims of this paper are twofold, viz. to review succeed in the Solid Path way and all these areMNRE
Sponsored Projects [1, 2, 3, and 4].

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 1
  INDIA ONE Solar, 1 MW Thermal Project at Mount Parameters required to collect the relevant data of the
Abu; using Cast Iron Storage receiver and to optimize the design are given below in which
 RKDF – RPI (USA) ,1 kW CSP Test Plant ; using following sensors were installed:
Halide Salt specially designed to conserve heat
 RGPV – Solar Flame (Japan) Project, 30 kW proposing Table 1 Sensors in the receiver measuring system
to use Rock Tower as Thermal storage material
Physical
Sensor type Location
2. “INDIA ONE”, a 1 MWe (3.5 MW thermal) solar Parameter
thermal project - aPerformance review Temperature Thermocouple type K Cold water inlet
Thermocouple type K Steam outlet
Project “INDIA ONE “, a 1 MW el. ( 3.5 MW) Solar Thermocouple type K Receiver iron core 1
Thermal Power plant at Mount Abu in western part of India
Thermocouple type K Receiver iron core 2
has been commissioned, with 16 hours thermal storage for
continuous operation. The project has been implemented by Thermocouple type K Receiver iron core 3
the World Renewal Spiritual Trust (WRST),with elaborate Thermocouple type K Receiver iron core 4
online monitoring and measuring system [1,2].The main goal Shadow Band
Solar radiation On site
of this performance evaluation was to measure the efficiency radiometer
of the 60m2 dish and iron receiver as thermal storage with Water flow Digital Water Meter Water inlet
direct steam production. First the efficiency of thermal Water amount Water meter Water inlet
storage into the receiver was measured. For that the solar
radiation input which was calculated by multiplying the Pressure sensor
Pressure Steam outlet
measured direct solar radiation (DNI) with the aperture diaphragm
(effective area) of the 60m 2 dish was put into relation to the
heat storage in the iron receiver. The stored heat was The measuring system of the receivers consists of 4 receiver
determined by multiplying the temperature difference (delta temperature sensors (type K thermocouples), a water meter, a
T) with the mass of the iron receiver and the specific heat of steam pressure sensor as well as a temperature sensor for the
cast iron. In a second stage, the effectiveness of the steam water and for the steam (type K thermocouples). The water
production was measured. In that stage the temperature meter allows the manual and automated reading of the water
reduction of the iron receiver was put into relation to the flow and the amount of water injected into the receiver
steam production. In addition the thermal loss of the receiver The data logger collected the following weather data:
was also measured.The design of the installed multi-channel
data logger based measuring system is shown in figure1, Table 2 Measured parameters in the weather
below.
Solar radiation Direct normal radiation DNI
India One Solar Power Plants station Global radiation
with 60 m2 Cast Iron Receiver
with coils for steam Diffuse Radiation
Generation Weather data Humidity
Air Temperature
Solar radiation DNR
Wind speed
Wind direction
Steam
peratu Receiver
Temperatures Figure 1:
T
Data
logger The weather data including the solar radiation is measured
with a Campbell CR10X data logger. All other sensors will be
Campbell
connected to a Campbell CR1000 data logger, which is
Water installed close to the receiver. The data loggers are
tank
programmed to collect the data of the sensors. The time base
of the program is 5 second and every 60 second a data sample
India One Solar Power Plant was recorded.
Configuration with measuring systems and DAS

The Campbell DAS was used to measure the performance

of the 60m2dish and the receiver / storage.
The measuring setup consisted of two sub systems. System
1collected the relevant steam-water data at the receiver.

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 2
System 2 collected the solar radiation and weather data.

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 3
Thermal Storage of “INDIA ONE” Project: 3.High Energy Density Thermal Energy Storage for
Concentrated Solar Plant- A 1 kW CSP at RKDF
The prototype consisting of the 60m2 parabolic mirror dish University
and the 3.9 ton cast iron receiver works very well. Most of the
solar radiation that hits the dish is reflected into the receiver A Solar thermal Unit with Tracker auto operation and
opening. Up to 82 % of the solar radiation is absorbed by the associated software has been installed under the MNRE
cast iron receiver. The steam production with a loaded receiver sponsored project at RKDF University in central India. This
works very efficient as can be seen from Figure 2. The stored unit is fully operational and full scale Performance Guarantee
heat is converted into steam with efficiency close to unity [1]. (PG) Testing concluded from May 2017 to 12 June 2017. The
Overall efficiency depends on the steam production and energy storage device, the revised Cast Iron core assembly
discharging procedure. Especially it depends on the storage (Figure3, below) with heat exchanger, boiler feed- pump
time. The highest efficiency was observed for afternoon piping and tracker etc. have been tested for reliability of the
discharge, when the energy that was accumulated on a single system. The temperature achieved at the tip of solar focal
day is immediately converted into steam on the afternoon of point was about 1400OC. The temperature at the core mid-
the same day. The longer the storage time, the more heat is point was found to be of the order of 660 OC which was found
lost and therefore the efficiency is lower. For morning sufficient to generate steam for heat transfer studies during PG
discharge the night losses reduce the efficiency. If the solar Test (Figure 4).
radiation of more than one day is accumulated, over 2 or 3
days, also the heat losses in daytime (open door) and night
losses are allowed to accumulate it would reduce the
efficiency even further (Table 3). The highest observed overall
efficiency was over 65 %.The highest observed loading
efficiency is about 82
% [2].

Table3 Overall efficiency of the first prototype

Time Slot Overall Efficiency

Afternoon discharge same day 58 %

Second day evening 53 %

Third day evening 52 %

Figure3 Revised Cast Iron Core

Figure2: Steam Generation from the Cast iron

Thermal Storage
Figure4: Performance Guarantee (PG) Testing

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 4
 Results of Performance Tests of the Project are summarized
below:
 Engineered composition of energy storage material (salt
crystals) was grown at RPI, USA which has the melting
point, specific heat capacity and density to enable high
energy storage density in excess of 300 kWh/m3and
operating temperature around 1000OC. Approximately
240 lbs. (110 kg) of high quality Alkali Halide crystals
were synthesized and grown at RPI, were shipped to
RKDF and used in the field unit during PG Test [5, 6].
The salt crystal has also been tested for its resistance to
moisture and humidity unlike pure NaCl crystals and then
filled in Core Assembly.

 The economic calculation for the laboratory scale

synthesis of the engineered salt crystals has been
performed. The cost of this storage material is calculated
as $1.9/kWh and the energy stored per unit mass is 140 Figure5: Thermal Cooling Profile in the RPI, USA Lab
Watt hr. / kg; over 300 kWh/m3 at the density of 2200 kg /
m3.
(140 Wh/kg x2200 kg / m3 = 308,000 Wh/m3 = 308 kWh/m3)

 The temperature necessary to achieve a thermal energy

density of 300kWh/m3 has been calculated to be 565 oC
based on the properties of the salt crystals.

 Also a specific formulation of SiC nanoparticle based

high temperature corrosion resistance coating has been
developed at RPI. A quantity of 3 liters of the SiC-
polymeric nano-composite was delivered to this
University and was used for coating the interior metallic
surfaces of the thermal storage unit [7,8].

 Direct steam generation by heating the water directly at

the focal point of the lens has been demonstrated. To
transport heat efficiently from the focal point of the lens
to the salt core, the thermal properties of the following
materials have been compared: copper, cast iron,
aluminum, cast copper alloy (C90500; gun metal). Based
on the analysis, a Cast iron and copper heat transfer tubes Figure6: Thermal Cooling Profile at Pilot Plant
and cage has been fabricated and tested. The steam
Installed at RKDF University with minimal insulation
generation for over 5 hours after sunset was found from
the heated Salt with minimal insulation.
Halide Salt based CSP Project- A Roadmap:
 Thermal Cooling Profile shows that the core cools down
to from 700 to 100OC in 8000 Minutes (almost 5 days) in Based on the experience on this pilot plant, following
lab experimentation, while at the Pilot Plant site, suggestions are made:
exhaustive experimentation was done during summer  In this project the Alkali Halide Salt was imported from
days of April & May 2017 and Salt cooling profiles RPI, USA by the project Co-Investigator Dr. Partha S
drawn between 2nd to 12th June 2017 is found to give Dutta. In future since the Technology transfer has been
temperature drop of less than 20oC per hour after sunset done, the Halide Salt crystals should be grown at the
and with continuous steamgeneration from 4 PM onwards University‟s Energy lab, where the required equipments
for about 5 hours (Refer Figures 5&6). are being procured.

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 5
  The Scaling up of the Plant should be done to about 30-40 process, the cost of this storage material is $1.9/kWh while the
kW range in which a simpler design of tracker should be energy stored per unit mass is 140 watt hr. /kg.
used and the entire core assembly should be under-ground
to reduce heat loss.
4. A 30 kW Cross Linear Concentrated Solar Plant at
 Based on preliminary economic analysis, auxiliary RGPV with proposed Storage of Heat in Rock Tower
heating system for steam in coal thermal power plants or
for applications in direct heat utilization in industry, RGPV University in Central India commissioned a R&D
Carbon Capture & Sequestration (CCS) processes, etc. project sponsored by MNRE on a path breaking and
seems more feasible than stand-alone CSP system using innovative solar thermal technology with the Japanese
the distributed storage type system (that‟s being collaboration with Solar Flame Corporation. This Technology
developed and demonstrated in this project). is known as Cross linear CSP (CL-CSP) andis amalgamation
Nevertheless, a significant engineering work is still of two exiting solar thermal technology i.e. Linear Fresnel and
needed in the near future to translate this concept into solar Tower. CL-CSP has virtues of both conventional Linear
commercially viable units in the field, in the second phase Fresnel and Tower technologies [7, 8].
of the project [10]. Setting up a test unit of 30kWt Cross Linear CSP System at
RGPV was done with the following objectives:
This project has proved the concept of retaining heat by  Demonstrate high temperature (>=600 degree
specially designed and lab grown Halide Salt and proper heat- C) attainment from CL-CSP.
transfer through medium weight Cast Iron Core and copper  Optimize simulation technology of CL-CSP.
coils for steam generation. Based on this research, the  Utilize to develop 1MWe plant.
following is a list of identified components that will be
necessary to be developed within India at ultra-low cost by A conceptual diagram figure of CL-CSP Technology
technology licensing and manufacturing technology transfer through integration of Linear Fresnel and Central Tower
approaches by commercial entities (from abroad) to translate technologies is shown as figure 7
the existing technology for large scale adoption:

1. Large area high optical quality Fresnel lens

manufacturing with low cost
2. High thermal storage density material manufacturing
3. Corrosion resistance nano-coating process
4. Ultra-low cost solar trackers
5. Energy efficient, low maintenance cost thermal
transport systems.

In conclusion, it may be stated that as per the encouraging

results of Pilot Scale 1 kW Solar Thermal Project in terms of
steam generation using retained heat of Salt material and
system performance, we must go for a moderate size, say
about 30 – 50 kW Plant with thermal storage following the
solid path-way & Fresnel Lens / Reflector with tracker and
associated software for accurate focusing of Sun rays on to the
Core. Figure7: A conceptual diagram of CL-CSP Technology

The 300 kWh/m3 of thermal energy density storage with the Also, a layout Plan of the CL-CSP system with an offset
lowest cost and material operability of 1000 oC were met by a location of receiver is shown at figure 8.In this innovative and
novel composition of NaCl-Fe2O3 composite. The iron oxide breakthrough CL-CSP technology temperature of 600 degree
content is less than 1 mole% in the crystal. In addition, silica C has been achieved by concentrating solar DNI. The
(SiO2) is present in the crystals in less than 0.5 mole%. This Heliostat used in this new technology is gyro type with E-W
composite provide the necessary 300 kWh/m3 of thermal and N-S tracking facility, which is first time manufactured in
energy density storage when heated to 565oC based on India(Figure 9). The power consumption for operation of this
analysis performed with the specific heat capacity and density. tracking mechanism is very less. The heliostat is very cost
This material has been successfully heated in air up to 1400 oC effective with reflective efficiency of 95% and weight 90 kg
for long period without any melting observed. Also the with approx. 3.5 m2area and air is being used as a heat transfer
material is resistant to moisture and humidity unlike pure medium in the solar air receiver which can further be utilized
NaCl crystals (table salt). At laboratory scale synthesis to generate steam. This Technology may be used for

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 6
substitution of coal for existing Thermal Power Plants during 5. Results & Discussions
the day Time. As the Thermal to Thermal
Conversation efficiency is over 80%, this can also replace Performance evaluation of 60 m2 disc and Cast Iron
Fossil Fuels in Factories/industries and can be used as Hybrid receivers as thermal storage with direct steam production on a
Technology for CSP Plants. It is proposed to use stone rocks 1 MW plant at Mt. Abu, other thermal storage like an
as storage material for the future CL-CSP project of 1MW innovative Halide Salt at MNRE sponsored RKDF- RPI, Indo-
capacity (Figure 10) US project and Rock storage for a 30 kW, MNRE sponsored
Cross Linear Concentrated Solar Plant (CL- CSP) project at
the State Technological University, RGPV, in Central India
reveals that all the three solid storage materials are capable of
providing thermal storage 24x7, provided heat transfer aspects
of working fluid are properly designed.
The Cast Iron Storage is though a massivestructure; it is
most suitable for direct steam generation with highobserved
overall efficiency of over 65 % and loading efficiency of about
82 %.
The Rock or Pebble storage offers a very low cost for large
scale application and is particularly useful for producing high
temperature steam in excess of 600 oC. Novel concept of CL-
CSP offers high cosine factor and has advantages of both
tower type CSP and linear Fresnel technology.
Development of innovative Halide Salt with high energy
density of the order of 300 kWh/m3 (at 1000oC), has
beenstudied together with modalities of indigenous
Figure8: A Layout Plan of the CL-CSP System development. It has been seen that the salt cools down to from
700 to 100OC in about 8000 Minutes (almost 5 days) in lab
experimentation, while at the Pilot Plant site, exhaustive
experimentation was done and Salt cooling profiles is found to
give temperature drop of less than 20 oC per hour after sunset
and with continuous steam generation from 4 PM onwards for
about 5 hours, with almost no insulation.
Out of the above three options of solid path-way, the Halide
salt based TES is found to be most optimum in terms of high
energy density, high core temperature and heat retention
capacity. A roadmap based on the tests and analysis of results
suggests that it will be necessary develop halide salt, heat
transfer mechanism within India at ultra-low cost by
Figure9: Heliostat with gyro type with E-W and N-S tracking technology licensing and manufacturing technology transfer
approaches by commercial entities (from abroad) to translate
the existing technology for large scale adoption.
6.Conclusions
Government of India through its Ministry of New and
Renewable Energy has set aggressive targets to achieve lower
component costs and higher system efficiencies in Solar
Thermal Projects. Over the course of about 5 years, the
program‟s portfolio of solar thermal research has developed
sub-system technologies potentially capable of efficient
operation at higher temperatures, and hold promise to be
reliable and cost effective.
Figure10: Proposed Rock Storage
In this paper we have selected three different Thermal
Storage Technologies of „Solid Path-way‟ for evaluating
theirstorage technologies to establish indicative
characterizations of energy density, conversion efficiency,
charge/discharge rates of heat etc. Research Development and
Design (RD&D) is to be focused on various components of

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 7
solar thermal system viz. heliostats, tracking mechanism, References
tower structure, receiver and storage medium.
[1] Jayasimha B K (2014)Fixed Focus Fully Tracked 60 SQM
The major issues today with Solid Path-way are identified Paraboloid Dish with Heat Storage. Sun Focus, Vol. 2, Issue 1,
as under: July – September 2014.
• Commercial CSP operators have little familiarity with [2] Jayasimha B K (2015) Renewable Energy systems for
handling and controlling solid heat transfer media to Community Scale Usage at Brahma Kumaris, Mount Abu.
dictate power plant characteristics. What major concerns Energy Future, April-June, 2015
exist to be able to operate a commercial power plant
relative to control, movement, containment, etc. of [3] Tamaura, Y., Shigeta, S., Meng, Q.L., Aiba, T., Kikura,
particle heat transfer media? What solutions and H. (2014)Cross linear solar concentration system forCSP and
demonstrations are needed to alleviate these concerns? CPV. Energy Procedia, 49, 249-256.
• Considering the particle material, what attributes are most
critical for CSP? What material properties represent the [4] Aiba, T., Tamaura, Y., Kikura, H. (2014)Image Processing
greatest risk for commercial viability? Ultimately, what for Cross Linear Heliostat Controlling System.Grand
particle material is most suitable for CSPs? Renewable Energy Proceedings, July 2014, Japan.
• What experimental and system testing capability are
[5] Dutta. P.S.(2011) Bulk Crystal Growth of III-V Compound
required and what is currently available in industry,
Semiconductors (in Comprehensive Semiconductor Science
public and private research organizations to measure the
and Technology, Editors: P. Bhattacharya, R. Fornari, H.
performance of particle based CSP components as well as
Kamimura)3, 36-80, Publisher: Elsevier.
integrating relevant subsystems.
[6] Dutta, P.S. (2015) Method and apparatus for growth of
With the aim of addressing some of the above front line multi-component single crystals&US 7641733 (2010)&P.S.
issues this paper examines performance evaluation of 60 m 2 Dutta, "Apparatus for growth of single crystals including a
disc and Cast Iron receivers‟ thermal storage with direct steam solute feeder”, US 8940095 (2015) – US Patents.
production. Various other innovative options of thermal
storage like Halide Salt at MNRE sponsored RKDF- RPI [7] Aiba, T., Tamaura, Y. Kikura, H. (2014)Improvement of
Indo-US joint project and Rock Storage for a 30 kW, MNRE image processing control accuracy for cross linear
sponsored Indo-Japanese, CL- CSP plant at RGPV are also heliostat.SolarPaces Proceedings, September 2014, Japan.
examined; and accordingly promising research directions are
proposed. [8] Tamaura, Y. (2014) CL-CSP Technology for Replacement
of Coal in the Power Plants. ICORE-2014, December 8-9,
Abbreviations New Delhi.

CCS Carbon Capture & Sequestration [9] Sethi, V.K., Pandey, M., Jain, P. (2013) Technology
CL-CSP Cross Linear Concentrated Solar analysis of Concentrated Solar Thermal Power Innovative
Plant COP Conference of Parties System Design Engineering IISTE, 4, 75-80.
CSP Concentrated Solar Plant [10] Sethi, V.K., Vyas, S. (2017) An Innovative Approach for
DAS Data Acquisition System Carbon Capture & Sequestration on a Thermal power plant
DNI Direct Normal Incidence through conversion to multi-purpose fuels – A feasibility
EES Electrical Energy Storage study in Indian context. Science Direct, Energy Procedia, 114,
IGCC Integrated Gasification Combined Cycle 1288-1296.
INDC Intended Nationally Determined Contribution Acknowledgement
HTF Heat Transfer Fluid The research projects described in this paper have been
MNRE Ministry of New & Renewable funded by Government of India through its Ministry of New &
Energy RD&D Research, Design & Development Renewable Energy (MNRE). The authors gratefully
RGPV Rajiv Gandhi Proudyogiki acknowledge the authorities of MNRE, New Delhi and the
views expressed herein might not reflect the views of MNRE.
Vishwavidyalya RKDF Ram Krishna Dharmarth
Authors also gratefully acknowledge the contribution of Prof.
Foundation Partha S Dutta of RPI, USA, Mr Jayasimha B K of„India One‟
RPI Rensselaer Poly Technic Institute Project& Dr. Savita Vyas, Associate Professor of RGPV in
TES Thermal Energy Storage providing useful data for preparation of this paper.

International conference on Energy, Environment and Economics, 14-16 August 2018 Page 8
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Entire Document
CHAPTER 1 INTRODUCTION 1 GENERAL In current state of affairs, requirement of energy is rising exponentially
in every sectors i.e. manufacturing, infrastructure etc. Infrastructure sector (i.e. hospitals, restaurants, lodges,
shopping complexes, educational big schools, colleges, corporate offices, multiuse etc.) is developing very
speedy due to growing population, need of high comfort level due to advancement in people’s living
standard, energy consumption is increasing rapidly.
Heating/cooling requirement of the building only consumes 30-34% of the total global energy
consumption. They are resulting key problems in a variety of areas like pollution control, change in climatic
conditions, global warming, ozone layer depletion etc. that creates many health issues. Right now energy
management and security are the globe priority topics. The Intergovernmental Panel on Climate Change
(IPCC) has accepted that Green House Gases (GHGs) are the first and foremost responsible for the various
environmental issues like climate change and global warming.

Large numbers of researchers suggest that promoting more use of renewable energy would be the
revolutionary way to control GHGs emissions. There are various renewable options available,choice of them
must be according to satisfying various criteria i.e. techno-economic, environmental issues, geographical
conditions, required energy quality, etc.

Energy intensity and its 24×7 availability have become the main relative measures of countries. Energy use
to Gross Domestic Product (GDP) is known as energy intensity. It’s value usually higher for developing
compare to the already developed countries. Higher value demonstrates huge energy dependence. India
consumes approximately 6% of world’s primary energy.

ENERGY SCENARIO

In India, 1363 MW was the total installed capacity in 1947. Then reached to 314.64 GW in 2017. During 2012-17
in the 12th Five Year, 88,425 MW target was set. Majority part means 50,000 MW was based on coal fired
thermal power plant.
Presently Major portion of power generation is based on coal, oil, gas, nuclear (70%), then hydro (17%) and
renewable (13%). But due the limited stock and its environmental issues compel to move towards alternative
source of energy (i.e. renewable-solar, wind, biomass, geothermal, ocean, hydrogen, etc.). The IPCC report
(June 2011) on the climate change by 2050 share of renewable energy in global energy mix could arrive up
to 77%.In India, in the 12th Five Year Plan (2012- 17), target of 29,800 MW power capacity (i.e. renewable
energy share more than 12% in terms of installed capacity) has been set from renewable energy sources.
Currently energy consumption rate in India has reached to just double compare to year 2000. There are
mainly five major energy consuming fields i.e. industries, agriculture, transport, communication, buildings (i.e.
commercial and residential).

NEED OF WORK

Major difficulties of 21stcentury are:

•Climate change has come out as a biggest problem

•Global warming due to GHGs

•GHG emissions due to use of fossil fuels

•Reducing balance of fossil fuels

•Availability of 24×7 electricity for all

•Variation in energy demand i.e. during shift change, night peak hours, etc.

To overcome from above mentioned problems, it is essential to encourage:-

•Effective energy management to conserve and balance demand & supply • Optimal use of natural energy
resources

•Discourage the use of fossil fuel based energy

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•Acceptance of various new hybrid technologies in which partly/fully energy is shared by renewable

•Promote new hybrid technologies coupled with energy storage

ENERGY SOURCES

3/35
It can be classified as primary and secondary energy sources. Primary energy sources are normally
categorized as renewable and non-renewable on the basis of their depleting characteristics, as shown in Fig.
1.1. Renewable energy derived from natural resources and they are automatically replenished. It is also
known as clean energy sources.

Fig. 1.1 Classification of primary energy sources

Secondary energy sources are derived from transformation of primary energy sources i.e. heat and electricity,
as shown in Fig. 1.2.

Fig. 1.2 Secondary energy sources

Renewable energy sources are inexhaustible but as per Indian climatic conditions solar energy is most suitable
energy source, shown as Fig. 1.3.

Fig. 1.3Classification of solar energy Solar Photovoltaic (PV) and solar thermal both are efficient, getting
popularity all over the globe. Selection of them is depends on utility, suitability. For energy storage and 24×7
energy supply solar thermal technology is getting more popularity than solar PV technology. Solar thermal
technology is also acknowledged as Concentrating Solar Power (CSP).

1.CSP systems CSP systems could be cost-effectively feasible at minimum 1600-1800 kWh/m2/year
Direct Normal Irradiance (DNI) by utilizing novel technologies, substances, economies of scale and
supporting renewable policies, etc [1,2]. CSP systems have a range of prime objectives. These are to work
environmentally safe, to diminish primary cost and ground area, to increase long-term system
trustworthiness, to make possible ease in service and maintenance. Sequestration of one ton of Carbon
Dioxide-Equivalent (CO2-e) equivalent to one CER unit. CSP technologies can be categorized as line and
point focus, shown in Fig. 1.4 [3].

Fig. 1.4Classification of CSP systems Parabolic trough comprises a parabolic linear reflector. It reflects or
focuses sun rays/radiations towards the receiver, shown in Fig. 1.5. Thermal heat is absorbed by working fluid
(i.e. molten salt, etc), that is filled in the receiver’s tube. Reflector has a tracking system to track the maximum
sun radiations. Working fluid achieves the temperature 150-350o C. Weight of parabolic linear reflector is
higher due to joint less design, therefore tracking systems consume enormous auxiliary power [4]. To conquer
this trouble, several curved mirrors are positioned rather than a single parabolic reflector that is known as
Linear Fresnel Reflector (LFR), shown as Fig. 1.6. LFR is less proficient compared to parabolic trough, due to
problem in tracking it’s multiple curved mirrors. As a result of fixed position of curved mirrors, at the time of
sunrise and afternoon cosine losses also arises in addition to longitudinal cosine losses as compared to
parabolic trough. Still having these drawbacks, it is trouble-free, less maintenance and generation cost per
kWh is lower than the parabolic trough [5, 6, 7]. Receiver’s position is kept at a higher position to reduce it's
shadow effect. In contrast, due to higher height and longer path, losses also increase. Solar tower is another
technology, as shown in Fig.
1.7 [8]. Array of heliostats tracks sun in double-axis. The working fluid is gets heated in between 500-1000o
C. Main constraint of this technology is the size, design of the tower. Parabolic Dish Collector (PDC) system
concentrates sun radiations towards receiver similar to parabolic trough but focused on a single point, shown
as Fig. 1.8. Working fluid gets heated up to 750o C. It is more efficient compared to others but suitablefor
small capacity applications only.

Fig. 1.5 Parabolic trough

collector Fig. 1.6 Linear fresnel

reflector Fig. 1.7 Solar tower

Fig. 1.8 PDC system

1.4 ENERGY STORAGE SYSTEMS (ESS) Rapidly rising demand of energy, fast depleting and limited stock of
fossil fuels, their serious environmental issues compel to shift towards to more use of renewable energy
sources.There are some critical issues while using renewable energy sources like reliability, quality, etc.
Energy storage systems have the capability to solve the problems up to some extent towards smooth and
continuous energy supply.

Due to rapid growth in infrastructure sector (i.e. communication, transport, road and rail networks, etc.),
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demand of energy is rising enormously and more than 20-30% demand is satisfied by non-
conventional energy sources [9].
Renewable or non-conventional energy sources are essential for the sustainable development, have many
advantages over conventional energy sources like availability, environment friendly, etc. But the most
important difficulty is the uneven generation of energy. Therefore, trustworthy and affordable energy
storage system becomes a prerequisite for using renewable energy [10-12]. Energy storage systems play
pivotal role towards smooth and continuous energy supply.

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Energy storage system holds the generated energy for a short time and supplied it according to need.
Therefore, energy storage system is the most capable technology to meet the rising demand of energy. A
device that accumulates energy is sometimes termed as an accumulator. There are various energy storage
systems. Paper presents brief overview of various energy storage systems. Many researches come on the
conclusion that renewable energy sources are the only option for sustainable development and appropriate
energy storage systems are the prerequisite. They have feature to store the energy and then release as and
when required. Classification of energy storage systems are shown as Fig. 1.9.

Fig. 1.9 Energy storage systems (Source: indiasmartgrid.org) Some ESSs i.e. flywheel energy storage,
compressed air energy storage, pumped storage, batteries, regenerative fuel cell storage,
superconducting magnet energy storage are explained here.

A. FLYWHEEL ENERGY STORAGE SYSTEM Flywheel energy storage systems store energy mechanically in
the flywheel rotor by rotating the rotor. Afterward generator is employed to convert mechanical energy to
electrical, as shown in Fig.
1.10. It is efficient and used for various applications. It is preferred due to compactness, light in weight and
high energy capacity. But due to limited amount of charge/discharge cycle characteristic, it is not cost-
effective.

Fig. 1.10Flywheel energy storage system B. COMPRESSED AIR ENERGY STORAGE It is also known as stone
storage system. Air is compressed to absorb and store heat energy after that released to utilized to generate
steam and electricity. Conceptual diagram is shown as Fig. 1.11. It is getting popularity due to quick start-
up, able to integrate with other energy sources but requires geological structure reliance [13].

Fig. 1.11 Compressed air energy storage C. PUMPED STORAGE In pumped storage system, water is pumped
and stored at height during off-peak periodsthen utilized to generate electricity to meet the peak demand, as
shown in Fig. 1.12. Hydro power plants store electricity in Megawatts (MW) or Gigawatts (GW). It has many
advantages i.e. fast start-up, reliable but requires large area and cost.

Fig. 1.12 Pumped storage

D. BATTERY Basic construction, working principle, functions of battery is very familiar, as shown in Fig.
1.13 (a) and (b).Portable batteries are well accepted in many small storage applications like transport
sector, utilities, etc. But it has some drawbacks like high cost, short life and regular maintenance.

(a)

(b) Fig. 1.13 Battery

E. REGENERATIVE FUEL CELL STORAGE It is electrochemical cell, converts source fuel (i.e. hydrogen,
methane, propane, methanol, etc.) into electricity. Hydrogen fuel cell is the one type of electrochemical cell,
where hydrogen is used the primary fuel and oxygen is also required, as shown in Fig. 1.14. They produce
electricity with very little pollution like hydrogen cell produces by product water. It has many advantages like
no green house gases, more operating time [14]. But has some disadvantages like facing difficulty in storing
of hydrogen due to highly inflammable nature of H2 and requirement of high capital cost due to platinum
catalyst.

Fig. 1.14Hydrogen fuel cell

F. UNDER-GROUND THERMAL ENERGY STORAGE Temperature of underground (i.e. below 2-3m) remains
constant round the year [15,16]. Using methods of ground coupled heat exchange systems(i.e. Earth Air
Heat Exchange (EAHE), as shown in Fig. 15, ground source heat pumps), natural heating/cooling air/liquid
could be done.

Fig. 1.15 Earth air heat exchanger

G. SUPERCONDUCTING MAGNET ENERGY STORAGE This is an advanced energy storage system. It stores
energy in the magnetic field within magnets that is developed by flow of direct current in a superconducting
coil, and then releases it within fraction of cycle, as shown in Fig.1.16.

Fig. 1.16 Superconducting magnet energy storage

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H. Molten salt

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Molten salt storage systems are the established commercially available concept for solar thermal power plants. D
For those systems, the molten salt storage media (about 35% of the direct capital costs) and the storage tanks (abo
°C, using molten salt as the HTF and the storage media, the capital cost ratios are 34 % for the storage media and 31
for the storage tank, respectively [19],

as shown in Fig. 1.17.

Fig. 1.17 Molten salt storage system I. Stone storage In this type of energy storage medium is pebbles that
has significantly higher thermal conductivity than normal concrete. Although the recipe of this material is
quite complex the maincomponent is quartzite, anatural geo-material readily available in many parts of the
world. Further, heat is transported in and out of the storage by way of a heat transfer fluid (HTF) which
flows through steel pipe heat exchangers that are cast into concrete storage elements, as shown in Fig. 1.18.
These elements are specially designed to deal with thermal deformations and stressing [20, 21]. Stone
storage may be a good technology for CL-CSP system.

Fig. 1.18 Stone storage system

It can be concluded from comparative study of various energy storage systems that for the need of large
scale energy storage underground thermal, pumped hydro and compressed air energy storage systems
are suitable. Superconductors are able to store energy with negligible losses. Fuel cells are a viable
alternative to petrol engines due to their high efficiency. Flywheels have a narrow range and suitable for
small scale operations. Molten salt and stone storage systems are gaining more acceptability for solar
thermal power plants [22-32]. 1.5 OBJECTIVES OF THE RESEARCH WORK According to current rising trend
in energy demand, reducing balance stock of fossil fuels and its impact on environment and health, it is
urgent to switch over to alternative source of energy i.e. renewable with efficient storage systems.

The objectives of the present work are to develop methodology for hybridizing the Solar thermal (i.e. CSP) with
thermal storage to 24×7 uninterrupted energy supply.

Objective-I

•Experimentally performance analysis of 1 MWe (3.5 MW) solar thermal power plant with 16 hours
thermal storage for continuous operation established at Mount Abu, Rajasthan.

•Experimentally performance analysis of 3.5 kWe (1 kWth) solar thermal power plant with 24 hours
thermal storage for continuous operation established at Bhopal, Madhya Pradesh.

Objective-II

•To compare the performance of above mentioned both solar thermal power plant coupled with storage
system for the Indian climate conditions.

EXPERIMENTAL SET UPS For controlling pollution level and fulfilling energy demand 24×7,
hybrid (combination of CSP with thermal storage) system is appropriate. Approach for the
research work is shown in Fig. 1.19. In research two experimental set ups are developed. They
are as follows:-

Experimental set up -01

- Mount Abu

Experimental set up

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-02

- Bhopal

Fig. 1.19 Approach for the research work

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 OUTLINE OF THE THESIS This thesis has five chapters as given below:

In Chapter 1, need of energy storage 24×7, overview on energy scenario, solar energy andapproach of
research work is explained.

Literature reviews on Concentrated Solar Power (CSP) systems, energy storage systems are presented in
Chapter 2.The gaps noticed in the literature review are brought out.

Experimental set ups for optimal operation of energy systems is presented in Chapter 3.

Experimental data analysis, results and discussions of energy storage systemsare presented in Chapter 4.

In Chapter 5, conclusions are drawn from both experimental set ups. Further scope of work is mentioned.
The references and publications of research papers are provided in Appendices.

CHAPTER 2 LITERATURE REVIEW 2 GENERAL Literature on the basic concept of solar thermal systems and
energy storage systems, their classifications, performances has been reviewed. It comprises the
performances fetches out their merits and demerits. Therefore, literature review is presented under following
heads:

- Power installed capacity of India

- Battery storage systems

- Thermal storage systems

2. 1 POWER INSTALLED CAPACITY

Worldwide energy demand is growing exponentially. Simultaneously environmental issues and reducing
balance of fossil fuels alarm and force us to switch over towards alternative options with 24x7 energy
storage. Power installed capacity of India is presented in Table 2.1.

Table 2.1. Total Power Installed Capacity of India (As on 30.09.2019) (Source: https://powermin.nic.in) Fuel
MW % Share Total Thermal 2,27,644 63.2 Coal 1,96,895 54.2 Lignite 6,260 1.7 Gas 24,937 6.9 Diesel 510
0.1 Hydro(Renewable) 45,399
12.6 Nuclear 6,780 1.9 RES (MNRE) 82,589 22.7 Total 3,63,370 100

2.2 ENERGY STORAGE SYSTEMS There are various options for 24x7 energy storage (i.e. batteries, solar
thermal etc.) coupled with alternative energy sources. 2.2.1 BATTERY STORAGE SYSTEM WITH SOLAR
PHOTOVOLTIC Tremendous literatures are available for battery storage systems. Cost analysis of 1 MW solar
power (i.e. Solar PV) 24x7 energy storage with lead acid batteries is presented in Table 2.2. Table 2.2. Costing of
1 MW Solar PV (24x7) Load required: 24 MWh-AC

Inverter efficiency @ avg 95% 24/0.95 = 25.26 MWh Battery @80% 25.26/0.80 = 31.57 MWh Charge
Controller @ 96% 31.57/0.96 = 32.89 MWh Array thermal loss @ 80% 32.89/0.80 = 41.11 MWh Radiation
available 5 KWh for 5.5 hrs PV array Capacity required 41.11 MWh/5.5 h = 7.47 MWp Cost of PV @ 4 crore
per MW 7.47 x 4 = 29.89 crores Battery cost for uninterrupted power supply and best quality power
output 30 MWhapprox. Cost of lead acid battery @ Rs. 7000 per KWh for period of 5 years 30,000 x 7000
= 21 crores for periodof 5 years, Therefore for period of 20 years, we have to replace the battery 5 times,
so total cost for battery will be around 21 x 4= Rs. 84 crores Cost of Li-ion battery @ Rs. 14000 per KWh
for period of 10 years 30,000 x 14000 = 42 crores for periodof 10 years, Therefore for period of 20 years,
we have to replace the battery 5 times, so total cost for battery will be around 42 x 2= Rs. 84 crores
Hence total cost of 1 MW PV based lead acid battery operated power plant: 29.89 + 84 = 113.89 crores say
Rs. 114 crores for stabilized uninterrupted quality power. So 1 MWh produces 1000 unit every hour, for 24
hrs 24 x 1000 = 24,000 unit daily Cost of unit sale @ Rs. 5/ unit 24,000 x 5 = 1,20,000 Cost of diesel plant
is around Rs. 18 per unit 24,000 x 18 = 4,32,000

2.2.2 THERMAL STORAGE SYSTEM WITH SOLAR THERMAL For MW scale solar thermal power plant based
on parabolic trough collector (PTC) and molten salt as thermal storage, the following cost analysis of 1 MW
solar power (i.e. Solar thermal) 24x7 energy storage is presented in Table 2.3. Table 2.3. Cost analysis of 1
MWth solar power 24x7 energy storage Ero trough + schott vacuum tube cost Rs ~ 30,000 per sq.m 1 MW
x 24 18% turbine 24 MWh electrical Thermal anticipating loss 10% 110/18 = 6.1 times Megawatt thermal

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capacity 24 x 6.1 = 146 MWH or say 150 MWH Average DNI 4.5 KWh/m2 Efficiency of trough 60% 4.5 x
0.6 = 2.7 Kwh/m2 of PTC Requirements 150 MWH = 150 x 1000 = 150000 Kwh/2.7 = 55,555 m2 of PTC x
30,000 = 16.666 crores BOP turbine Island Storage-molten salt KNO3 + NaNO3 ~ Rs 120/Kg

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150 MWH x 0.7 ~ 105 MWH thermal storage = 105 x 1000 x 50 x70 = 36.5 crores storage cost Total cost
16 cr + 36 cr = 60 crores Hence total cost of 1 MW solar thermal with molten salt thermal storage power
plant is Rs. 60 crores for stabilized uninterrupted quality power. So 1 MWh produces 1000 unit every hour,
for 24 hrs 24 x 1000 = 24,000 unit daily Cost of unit sale @ Rs. 5/ unit 24,000 x 5 = 1,20,000 Cost of
diesel plant is around Rs. 18 per unit 24,000 x 18 = 4,32,000

It should be noted that life cycle assessment of solar PV based power is required replacement of batteries after
5 year in case of Lead acid battery and 10 years in case of Li-ion batteries. There is no replacement of solar
thermal power plant and continue to run as it maintain. Hence PV based plant cost will be around Rs. 114
croresand solar thermal based plant is Rs. 60 crores for stabilized uninterrupted quality power. It can be
concluded from above analysis that considering the technical and economical benefits of solar thermal power
coupled with thermal storage technology in comparison to solar PV system coupled lead acid batteries/Li-ion
batteries storage technology, it is better to opt thermal storage technology even though it is costlier during
initial capital cost. For the 20 years, considering all costs (i.e. capital plus maintenance) values of Net Present
Value (NPV) and Internal Rate of Return (IRR) would be better for solar thermal energy storage systems. 2.3
THERMAL STORAGE SYSTEMS

Powell et al. [33] observed that CSP or solar thermal power technology is suitable to coupled with any
alternative strategies like coal, natural gas, biofuels, geothermal, photovoltaic (PV), and wind.

Hybridisation provides high reliability, efficiency, reduced capital costs due to resource sharing. Overall
system’s efficiency is improved via synergy of the various resources or energy sources. An additional benefit
of CSP technology is the appropriate for coupling with energy storage systems i.e.thermal energy storage
(TES).

Globally four main CSP technologies are popular for power generation

1. Parabolic Trough (PT) 2. Solar Tower (ST) 3. Linear Fresnel Reflector (LFR) 4. Parabolic Dish (PD) Solar
thermal power plant option in India on the basis of actual DNI of solar radiation resource assessment
(SRRA) and solar Atlas of SRRA. It will also cover the possible option of thermal storage for solar power
plant and 24x7 operational conditions on various part of the country. The government of India launched
the National solar mission which targeted 100,000 MW of grid connected solar power by 2022. The
majority contribution is with solar PV technologies because of widespread development and reach to grid
parity as per last bidding of Rs 3 per unit cost. However, solar power plant with 24x7 operation, the same
PV power plant combined with MWh batteries cost around 24-25 crores which is quite expensive and
inefficient. On the contrary, same power with solar thermal plant with thermal storage, project cost will be
lowered or at par with solar PV with stable grid reliability. India has a opportunity to become a major
contributor to development of solar thermal power. According to India Metrological Department (IMD), clear
sunny weather is experienced for 250-300 days a year by most part of India and it varies in various part of
India region to region. India has highest DNI range to lowest DNI range (Ladak to Cherrapunji). Therefore
depending on technology option available, the available, the area wise regions need to be sort-out and
propose a solution with technology and storage option. The different climate zone of various part of India,
and suitable technology along with specific thermal storage systems given in Table 2.4.

Table 2.4 Different climate zone of various part of India, suitable technologies & thermal storage systems
Temperature and DNI Parts/regions of India Suitable solar thermal technologies coupled with storage systems
High temperature and high DNI Zone Rajasthan, Gujarat, some part of Madhya Pradesh, Adhra Pradesh,
Karnataka, TamilNadu, Bihar, Chhattisgarh, Orissa and Maharashtra. PTC, ST, LFR and PD with all thermal
storage Moderate Temperature and low DNI Delhi Haryana, Uttar Pradesh, some part of Bihar Chhattisgarh,
Orissa and Maharashtra, West Bengal and North East Region. PTC, ST, LFR and PD With molten salt thermal
storage Low temperature and high DNI Range Leh, Ladak, Kargil and some part of J&K.

Parabolic Dish (PD) with cast iron storage

Worldwide accepted thermal storage options are molten salt, stone storage, cast Iron & wrought iron
storage and PCM. Lappalaineb et al. [34] experimented on hybrid CSP with two thermal energy storage (TES)
at Almeria in Spain and finally validated through simulation, found good agreement between them. Two
thermal energy storage system were (i) pumping molten salt (MS) from cold tank to hot tank, and (ii) free
drainage from the upper (hot) tank to the lower tank. It was concluded that molten salt was suitable for CSP

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and other application i.e. nuclear power. Bauer et al. [35] gives an overview of commercial molten salt TES
systems for CSP plants. They explained the outcome on prime decay reaction with nitrite formation in the
melt and oxygen release and then a secondary decay reaction with alkali metal oxide formation in the melt
and nitrogen/nitrogen oxide release. Results point out that the kinetic time constants of these two decays
are not the similar under the observed experimental conditions. Therefore, further future work on the nitrate
salt chemistry near the stability limit is required. Cristina et al. [36] designed, built and tested a molten salts
pilot plant at representative scale of 8 MWhth. Main components i.e. storage tanks, heat exchanger were
tested deeply. It was found

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that MS TES gave satisfactory results for large commercial CSP projects. Cristina et al. [37] observed that in
comparison to sensible and latent heat storage, thermochemical storage (TCS) systems still needed to be
researched thoroughly. Energy Demand of World Firdaus et al. [38] had briefly discussed through the paper
that the energy demand of the world had been huge potential through solar energy. There is a limited role
play in present condition. It consists of the up to date generation of the concentrator and on how the other
parameters comparison and consider the affordable one. Each and every generation of concentrator are
compared simultaneously with each other and further optimization in concentrator had also been
understanding for future scope. Concentrator A Dang [39] had discussed the existing concentrating solar
technology in his paper. Apart from that, he had also analyzed the particular concentrator designing,
manufacturing, modification, testing, tracking mechanism, and material in use, optical and thermal
performance. Some modification had also been provided to enhance the performance of a concentrator. The
different focusing concentration technology and direction vary calculation had been showed. T Cooper et al.
[40] had narrated about the line to point focus concentrator by maintaining the tracking mechanism on a
single axis and reducing the cost of a collector with the help of such design consideration for the primary
concentrator, this can be achieved while allowing the thermodynamic concentration limit. The proposed solar
concentrator design is well suitable for large scale application with the concentration ratio 500-2000. D
Gadhia et al. [41] had worked on the development of parabolic solar collector with such inputs and
collaboration. The slight growth in solar technology the food processing technology and all other applications.
The approved technologies and its commercialization were successfully installed and benefits were realized.
Apart from that, the feedback of this technology was also given by their users. The clean development
management and formation of eco-friendly environment will safe us and also our planet earth. Receiver: T
Lee et al. [42] had proposed his motive about the design optimization of a solar tubular receiver to rise up the
working performance. The poor condition which was affecting its performance was analyzed. The multiple
factors affecting the system performance were such that the length of the receiver, the maximum number of
inlet pipes, porousness and the thermal conductivity of that porous medium. The maximum possible effect in
each variable on certain physical condition like maximum temperature and pressure drop is identified and the
suitable optimal design is sorted out. Thus the rare design is suggested to grow up the factor of efficiency.
Further, this alternate design will overcome its performance through the manufacturing process. AL Avila-
Marin
[43] had completely reviewed the volumetric receiver design to optimise minimal heat loss. They have
given a comparison between the volumetric receiver and tube receiver with their different working principle
and geometry. The volumetric receiver includes the porous material which easily absorbs the highly
concentrated radiation inside the volumetric structure. Then further the heat is transferred to the fluid
passing through the same structure. It had been widely used in central receiver system technology. Thus the
study concludes about the pre-existing and up till date volumetric receiver in use was discussed and
analysis of various parameters was given and considered out the best configuration. R Duggal et al.[44]
had numerically identified about the three- dimensional models of trapezoidal cavity receiver which is in use in
linear Fresnel reflector with water as a heat transfer fluid was analyzed by both. They also fully described the
3D model. The issue of thermal loss was predicted and certain parameters were noted down and the effect
was also seen with variant losses. On the other hand, the suitable design considerations were analyzed and
an alternate receiver was proposed for further use.

Thermic Fluid B Gobereit et al. [45] had completely summarized about the computational fluid dynamics
model of a particle receiver gives out the profound information regarding various known factors related to it
and also it is compared truly compared with the pre-existing prototype. The thermal radiation losses predicted
by the CFD model are totally different as per the estimated one. It is a true concept for increasing the system
efficiency for various solar thermal applications. MJ Bustamante [46] had described the heat transfer fluids
transferring and utilizing the collected solar heat with the help of solar thermal energy collectors. The solar
thermal collectors are categorized according to the temperature range namely low, medium and high. Low-
temperature solar collectors use phase changing refrigerants and water as heat transfer fluids. The uses of
water-glycol mixtures as well as water-based nano fluids are obtaining momentum in low-temperature solar
collector applications. The hydrocarbons are also used as refrigerants in many cases. In medium
temperature solar collectors the heat transfer fluids include water, water-glycol mixtures i.e., trimethylene
glycol (green glycol) and also naturally occurring hydrocarbon oils in various compositions such as aromatic
oils, naphthenic oils, and paraffinic oils in their increasing order at suitable operating temperatures. In high-
temperature solar collector, the synthetic hydrocarbon oils as heat transfer fluid are used as a fluid of choice in

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wide applications while other heat transfer fluid are being used with varying degree of experimental maturity
and commercial viability – for maximizing their benefits and minimizing their disadvantages A Sinha [47] had
reviewed the concentrating solar technologies with the heat transfer fluid which are recently in use in India.
The various kind of heat transfer fluid possessing variant physical and thermal properties. As per our needs,
the concentrating solar power plant had formed an alternative source in power generation around rural field
area. The such installed concentrating solar power plant includes

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the heat transfer fluid Therminol VP-1, Synthetic oil, Dowtherm A, etc are in use. Heat transfer fluid like Hitec
salt, dowtherm A are very stable compound and is used for power generation limited to 700 °C. Some
alternate sources of energy are essential to cover up the gap between demand and supply rather than coal.
Through this paper, he had discussed the various properties of each heat transfer fluid with reference to
concentrating solar power plant in India. They also suggested us about the halide based salt utilization in
these plants for small scale power generations in rural areas. To utilize the phase change material mainly for
two different motives i.e., primary for working of the heat transfer fluid and secondary regarding thermal
energy storage. Solar Thermal Energy Storage A Sharma et al. [48] had been given a successful review
regarding the thermal energy storage system with the phase change material concept and also its applications
had been discussed in this paper. They have discussed the latent heat storage system with PCM having a
dominant way of storing. There is an advantage of high storage density and isothermal characteristics in this
particular storage. There had been a number of applications with the PCM with latent heat storage. The
various phase change material had been studied and analyzed about its melt fraction and thermal properties
and.

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This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorpora
PCMs for use in different applications.

BP Jelle et al. [49] had disserted in their paper on thermal energy storage system according to phase change
material which can lower the energy consumption of the buildings. The releasing and storing of heat in a
certain temperature limit, the inertia of the building increases and the room temperature becomes stable. The
maximum amount of energy is stored at a high temperature and return back at a certain temperature due to
an increase in thermal mass at a narrow temperature range. A high potential of energy had been saved but
not yet that much optimized for building application purpose. Some known materials with a transition around
comfort temperature, and those existing do have a relatively low heat of fusion. S Kuravi et al.[50] had
narrated about the

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thermal energy storage technologies and the factor which are to be considered at different levels in concentrating so
plants. The thermal energy storage

is the vital component in concentrating solar plant for increasing out the efficiency and the performance.
There is a lack of storage system in solar power plant and the designing along with the integration of the
storage system is not so highly focused to built it. The study of the various thermal energy storage system
is pointedly specified and other economic aspects are also summarized. Thus the arrangement of the
various storage system is required to achieve the expected efficiency. S Khare et al. [51] had discussed the
alternative source apart from the conventional energy. The suitable non- conventional energy is solar energy
which is eco-friendly in use. The solar power in India is developing day by day. It is easily available
everywhere also the demand of various sector through solar energy is increasing widely and if we want to
save our environment then we must use solar as a part. In this paper, the schemes available in India, solar
mission, a case study of some applications, etc. is discussed shortly. 2.4 RESEARCH GAP After reviewing
different research papers, following research gaps are identified: • Remarkable scope of energy storage is
available coupled with solar thermal (CSP) systems in in hot climatic conditions i.e. India. Only a few
concerned research papers are accessible for making available electricity 24×7 in hot climatic conditions i.e.
India. • Thermal energy storage system (i.e. solid) coupled with solar thermal (CSP) systems for the Indian
climatic conditions is not found.

CHAPTER 3 EXPERIMENTAL SET UP

3. GENERAL Solution towards energy security and various environmental issues is the adoption and
promotion of renewable energy systems. Solar energy has the tremendous scope of energy generation i.e.
electricity and heat both. In this chapter, methodology adopted for CSP system with energy storage system
is presented. The adoptability of solar thermal system can significantly be enhanced by coupling energy
storage system. Title of the first experimental set up is “1MW electrical (3.5 MW thermal) solar power plant
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with 16 hours thermal storage capacity”. The aim of the experimental set up is to establish a
1MWcapacitysolar thermal power plantwith16hoursstoragefacilitybased on Parabolic Solar Reflectors at an
estimated solar to electric efficiency of about12%. Title of second experiment set up is “high energy density
thermal energy storage for concentrated solar plant”.

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 DESCRIPTION OF EXPERIMENTAL SET UPs

Experiment set up-I Experimental set up-I is established at near Shativan Campus, Bhrahma
kumaries, Talheti, Abu Road-307510, Rajasthan. Design parameters of the experimental set up-
I: Parabolic Solar Reflector (PSR): 60 SQM PSR is presented as Fig. 3.1. It is completely designed
with space frame comprises with solar grade curved mirrors. Mainly it has four parts (i) Supporting
stand (ii) Rotating wheel (iii) Central bar space frame and (iv) Outer frame with cross bars and long
bars.

All the materials used for the PSR are of mild steel grade as per IS 2062 and as per IS 4923 for solid and hollow
sections, respectively. All the surface areas are well coated with paints (epoxy paint and PU paint) for the long
life service.

Fig. 3.1 Parabolic solar reflector Main parts of Parabolic Solar Reflector

Supporting Stand: Concrete foundation is done for providing proper strengthto60SQM Parabolic Solar
Reflector. Designing of stands is done according to latitude of the location, hence different design is done
for different locations. Base of supporting stand is selected in triangular shape for providing proper
strength with less land requirement. Rotating Wheel: It links to supporting stand and parabolic frame, as Fig.
3.1.Materials employed for rotating wheel are of mild steel grade as per IS 2062 and M.S. sections as per IS
4923. The daily tracking arrangement is through rack and pinion arrangement with actuators and DC
motor for daily rotation. Parabolic Outer Frame: The next main component of the Parabolic Reflector is the
parabolic frame. The outer frame is designed in three parts as per the requirement of flexibility and rigidity
balance to accommodate various shapes of parabola’s for different seasonal requirements. This outer
frame provides hinge support to various cross-bars and long-bars that are designed to support the mirror
pieces that make a perfect parabolic reflective surface, as Fig. 3.1. Central Bar Space Frame: It is a backbone
of the outer parabolic frame. This is used for tracking mechanism on the longitudinal axis of the parabola.
This has three mechanical actuators that are driven by DC motors. This structure due to its flexible
behaviors enhances the concentration ratio of the output focus at the focal point. Flexible Parabola: The
structural design has the flexibility option in the structure to provide flexible parabola, presented as Fig. 3.2.
There is different parabolas option for different seasons. These flexible parabolas are possible through
automatic dual axis tracking mechanism. There are three types of tracking systems: (i) Daily tracking: This
tracking mechanism allows the Reflector to track the sun throughout the day. This is done with the help of
rack and pinion mechanism. (ii) Seasonal tracking: This tracking mechanism allows the Reflector to align
with the changes in the angle of the sun due to change in the season. (iii) Shape change tracking: This
tracking mechanism allows the reflector to change the shape of the parabola to increase the
concentration ration of the focus.

Fig. 3.2 Flexible parabola

All the three types of tracking systems are fully automatic coupled with mechanical actuator (D1) and shape
change actuators (S1,S2,S3,S4), DC motors, micro controller and programming systems, that all is referred as
“IMATRACK POWER”, as Fig. 3.3. It tracks to 60 SQM PSR.

Fig. 3.3Various actuators Static Cast Iron Cavity Receiver:

Receiver is constructed by monolithic cast iron, in conical cavity shape, opening of 500 mm and 700 mm
deep in conical design. A single helical boiler grade coil is wound around the monolithic conical cavity cast
iron body around the periphery, as Fig. 3.4. (a)

(b) Fig. 3.4 (a) Receiver coil drawing (b) Block drawing The whole body of receiver is shielded by mineral wool
insulation of 6-inch thickness with aluminum cladding to decrease heat loss to air. Receiver is mounted on a
triangular structure with fixtures to provide stability with minimum heat loss.

Experiment set up-II Experimental set up-II is established at Ram Krishna Dharmarth
Foundation (RKDF) University, Bhopal. Details of equipment used in experimental set up-II (as
shown in Table 3.1) Table 3.1 Equipment list used in the experimental set up Sl. Name of
Specifications Make / Cost Date of Utilization Remarks No Equipment Model (FE / Rs) Installation
Rate (%) regarding

Maintenance /
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Breakdown 1. Solar Tracker Unit Tracker Unit Assembly complete with Micro-Controller with Computer
Interfacing Facility and full auto operation throughout the year and data logging system.

7,04,175.00 23rd Jan,2016 100% Control System Components Replaced 2. Heat Transfer Unit (Boiler Feed
Pump & Piping & Core of MS and Copper) Plunger Type Positive Return Metering; 0-50 LPH with discharge
pressure 11kg/cm2 ; Flooded

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suction; Pump speed – 145 RPM; All material SS 316 ; Plunger – Hard Chrome Plated D4#23P SR NO: CE-
5606 Dosing Metering Pump 1,19,914.85 26th Mar,2016 75% Piping work was revised for better steam
generation and the Core s under revision to Cast-Iron crucible design for improving steam parameters. 3.
Core Material from RPI USA Mild Steel, Copper and Cast-Iron 3,38,401.00 7th May,2016 75% Size of Crystal
revised 4. Fresnel Lens 1100mm(dia.) x 5mm(thick); MMA Polymer; Focal Length of 1300mm HS
71171900000 Focal length 1300mm 1100mm Dia. 31,000.00 23rd Jan,2016 100% -

Other materials are 1. Thermocouple R-Type ; 360mm Long; 0-1500o C range ; Compensating Cable SS
braided and Digital Meter along with accessories. 2. Thermo-Electric Device duly designed and fabricated
at Micro-and nano Fabrication Clean Room (MNCR), RPI, USA. Conversion Efficiency more than 5%. 3.
Thermal Storage Salt for Research developed at the RPI Lab, USA and imported vide invoice dated 25th
April, 2016- having high “Energy Density” exceeding 300kWh/m3and Density 2200kg/m3.

The aim of this project is to demonstrate a solar thermal storage system with 1 kW capacity of volumetric
energy density, exceeding 300 kWh/m3 and capable of operating at high temperatures up to 1000 oC. In
comparison, the volumetric energy storage density for water is typically around 80 kWh/m3 and 200
kWh/m3 for molten salts used in solar thermal plants. The unique aspects of this system are the selection of
an alkali halide salt with high melting temperature and a corrosion-resistant, low-cost ceramic container
material. Flux grown crystals of mixed alkali halide compounds doped with metallic impurities shown as Fig.
3.5. The thermal storage unit is coupled with a high solar concentrator system (1000
– 10,000 Xs).In this project, we propose to develop and demonstrate an affordable, high energy density
thermal storage system that can store heat at temperatures around 1000 oC. Cast-iron core crucible design
and schematic are presented as Fig.3.6 and 3.7, respectively. Solar thermal storage with solar tracker unit is
shown as Fig. 3.8 and 3.9.

Fig. 3.5 Size and photo mixed alkali halide compounds doped with metallic

impurities Fig. 3.6 Cast-iron core crucible design

Solid CastIron

Core Focus Area

Salt Crystals

Heat

Exchanger

Quartz Glass for Lid

Fig. 3.7 Schematic of experimental set up

Fig.3.8 Installation of the solar thermal storage and solar tracker

unit Fig. 3.9 Solar thermal storage with solar tracker unit

Fig. 3.10 Tracking motor

Fig. 3.11 Tracking rope & Chain

CHAPTER 4 EXPERIMENTAL DATA ANALYSIS, RESULTS AND DISCUSSIONS 4 GENERAL CSP coupled with
storage system
is the promising technology for 24×7 energy supply. Experimental results of both the arrangements are
satisfactory. It is observed from experimental results that solid storage systems are the appropriate option.
4.1 PERFORMACE OF REFLECTOR ROUND THE YEAR (Experimental Set up-I)

The aperture area of the reflector is as shown in Fig. 4 changes occur in different seasons as per the
inclination with the polar axis.

Fig. 4.1 Changes in aperture area of reflector

Variation in the aperture area for a 60 SQM Paraboloid reflector round the year is shown as

Fig. 4.2. 60
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50

40

30

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20

10

0 0306090120 150 180 210 240 270 300 330 360390 Day of the year

Fig. 4.2 Variation in the aperture area

The thermal output from the reflector is computed by the aperture area of the reflector, the Direct Normal
Irradiance (DNI) and the efficiency factor of the reflector. The efficiency factor of the reflector depends on
different things i.e. mirror reflectivity, surface of mirror cleaned, purity and accuracy of mirror, normally it is
taken 60% as efficiency factor of reflector surface. Actual DNI is calculated on the location for every 10
mins and averaged out for hour and then for the day. So the output of Reflector = aperture area (SQM) x
avg. DNI for the day (kWhrs) x efficiency factor. Ave. DNI of the location for the year 2010 is shown as Fig.
4.3.

1.00 0.00 1.31 1.49 3.00 2.00 2.96 3.55 4.00 4.01 5.00 5.25 5.63 5.40 5.44 5.62 5.91 6.03 DNI Radiation in
kWhr/day from
avg. month 2016 DNI… 7.00

6.00 1-Jan

1-Mar

1-May-10

1-Jul-10

1-Sep-10

1-Nov-10

1-Dec-10

1-Oct-10

1-Aug-10

1-Jun-10

1-Apr-

1-Feb-

Fig. 4.3 Ave. DNI of the location for the year 2016 Thermal output of 60 SQM reflectors for the year 2016 is
shown as Fig. 4.4.

Fig. 4.4 Thermal output of 60 SQM reflectors for the year 2016

THERMAL BHAVIOR OF RECEIVER 1. Without front glass The testing was carried out in the month of May
2011. The Static receiver is charged during the day time through the solar rays’ reflection focus from the
Paraboloid reflector, shown as Fig. 4.5.The Receiver is charged without front glass covering. Observation:
Max. Temperature recorded is 400 oC

Fig. 4.5 Thermal behavior of the Receiver without front glass

2. With front glass cover at receiver opening as shown Fig. 4.6.

Observation: Max. temperature recorded – 450 oC

Fig. 4.6 Thermal behavior of the receiver with front glass

3. With front glass covering at the receiver opening and with water flow through the heat transfer coil, shown
Fig. 4.7.

Observation:

•Flow rate of water through the heat transfer coil – 3.5 litrs/min. • Max. temperature reached at the
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Receiver – 450 oC • Max. pressure of steam discharged – 42 bar • Max. temperature of steam discharged
– 430 oC • Discharging 2/3rd of time superheated steam and 1/3rd of time saturated steam before rapid
temperature drop.

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Fig. 4.7 Thermal behavior of the Receiver with front glass covering at the receiver opening and with water
flow through the heat transfer coil

4.2 PERFORMACE REPORT (Experimental Set up-II) Project commenced on 6th September, 2015 then
completed on 18th March, 2017. Various observation and measurement have been taken during this period,
they are as follows: • Energy storage in form of heat offers a potential pathway for small (local) and large
(utility power plants) scale applications. Thermal storage systems provide a unique opportunity to store
energy locally in the form of heat that cannot be transported over long distances. Current thermal storage
systems are still in its infancy. The most common ones are large, water-heating storage tanks and molten
salt-based systems at solar power plants. These systems have been designed based on the economics of
water and salt, the heat capacity of water, and the latent heat of salts. Research on a large host of sensible
heat storage and phase-change materials have been conducted over the past two decades. The materials
parameters that are relevant for this application are: melting point, boiling point, vapor pressure, density, heat
capacity, thermal conductivity, latent heat of fusion and chemical reactivity. • While it is intuitive that
increasing the temperature of storage could pack in more energy, barriers to the development and
deployment of high energy density storage remain, including handling materials at high temperatures,
associated systems costs, and operating costs. Thus sensible thermal storage systems are cost prohibitive.
Phase change materials (PCM) do provide a viable economical solution for higher energy storage density.
However, operation temperatures limit current PCM systems; higher temperatures cause chemical
instability and reactivity with containers. Development of affordable high-density thermal storage system will
only be possible by utilizing low cost earth abundant thermal storage materials in conjunction with suitable
thermally insulating container materials. • Current heat storage systems utilize either sensible heat storage
(i.e. water in storage tanks) or latent heat storage (i.e. phase-change materials such as molten salts). The
relatively low operating temperatures of these systems limit their capacity to store thermal energy; storage
systems with higher temperatures would be more economical. In this project, we are developing an
affordable high energy density thermal storage system that can store heat at temperature around 1000 OC.
The unique aspects of this system are the selection of an alkali halide salt with high melting temperature
and a corrosion resistant cheap ceramic container material. The thermal storage unit will be coupled with a
high solar concentrator system (1000 – 10,000 x). • During 3 days of trial run from 11 May to 14th May
2016, we have achieved a drop in temperature at the middle of core to the tune of 2 to 2.5 oC per hour in
15 hours from 310oCto 278 oC. The trial operations will continue for about 6 month to get study steam
flow at highest possible temperature and pressure to run the steam turbine for Power generation to the
tune of 300W electric (1000W thermal). • The temperature achieved at the tip of solar focal point about
1400 oC. The temperature at the core mid-point was found to be of the order of 310 oC which may be
sufficient to generate steam for heat transfer studies.

Fig. 4.8 Filling of salt at core of

receiver Fig. 4.9 Focus of lens at tip

of receiver

Fig. 4.10 Temperature (max.) recorded during field

test Fig. 4.11 Salt heating and cooling cycle during

lab test Fig. 4.12 Steam output of system

`CHAPTER 5 CONCLUSIONS AND FUTURE SCOPE 5 GENERAL Energy security, high efficiency with
economy feasibility, sustainable development with environmental protection are the globally primacy
topics. In present era the growth of population is very fast, resulting energy demand is also increasing
exponentially mainly due to their modern life style, etc. Therefore, renewable based 24×7 energy solutions
have to be invented. Conventional renewable energy generation systems have enormous issues i.e.
uninterrupted supply, energy storage with controlled GHGs emissions. Unlike conventional renewable
approach, an innovative passive hybrid approach is the coupling of energy storage system with
Concentrated Solar Power (CSP) system. By using solar energy, the hybrid system is able to generate
huge amount of energy. These systems are characterized by various advantages i.e. appropriate efficiency,
no emissions of GHGs with very low operation and maintenance costs etc. Two experimental set ups with
objective to proficient exploitation solar energy and store through solid storage systems to provide the

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power 24×7. A 1 MWe (3.5 MW thermal) solar power plant with 16 hours thermal storage capacity and A 1
kWe high energy density thermal energy storage for concentrated solar plant were experimented and
found satisfactory results as per Indian climatic conditions. 5.1 CONCLUSIONS FROM PERFORMANCE OF 1
MWe (3.5 MWth) SOLAR POWER PLANT WITH 16 HOURS THERMAL STORAGE CAPACITY The plant operates
on
Rankine cycle principle. The Parabolic Reflector concentrates the solar radiation towards the in-house
developed, highly efficient cavity receiver. The cavity of the Receiver which is made of monolithic cast iron
acts as perfect black body and thus provides excellent thermal storage. The boiler grade coil around the
body acts as a heat exchanger which allows for

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water to exchange heat and convert into steam. The thermal storage can be operated between 250 oC to
550 oC and can be discharged on demand. The steam generated is mostly super-heated steam and the
rest is saturated steam at operating pressure from38 bar to 44 bar gauge pressure. 5.2 CONCLUSIONS
FROM PERFORMANCE OF 1 kWe HIGH ENERGY DENSITY THERMAL STORAGE It was concluded from various
readings that the temperature achieved at the tip of solar focal point about 1400oC. The temperature at
the core mid-point was found to be of the order of 310oC which is sufficient to generate steam for heat
transfer studies. 5.3 COMPARATIVE ANALYSIS OF SOLID THERMAL STORAGE SYSTEM WITH OTHER
SYSTEMS S.N. Parameter India One Mount abu MNRE R&D Project , Bhopal Technical Parameter 1 Thermal
Capacity 3.5 MWth 40 KWth 2 Electrical Capacity 1 MWe 10 kWe 3 Heat source(CSP System) 60 sq m
parabolic Scheffler dish 16 sq m parabolic Scheffler dish 4 Storage medium Cast Iron Halide Salt 4.1
Specific heat(KJ/Kg K) 2100 3500 4.2 Life (year) 25 35 4.3 Heat redundancy ( min) 6000 8000 4.4 Density
(kg/m3) 120 80 4.5 chemical composition
4.6 Chemically activeness inert inert 4.7 Impact on Environment 5 Area (Acre) 8 4.5

5.4 FUTURE SCOPE The long term aim of this research work is to develop the necessary technology know-
how to enable the manufacturing process in India for large scale MW systems.Promote energy efficient
concept of steam generation through solar thermal storage and apply in Carbon Capture Sequestration
(CCS) system, shown as Fig. 5.1.

Fig. 5.1Steam generation through solar thermal storage and apply in CCS system

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APPENDIX-A: PUBLICATIONS International journals (1) Anil Kumar, V K Sethi, Suresh Kumar Soni, Sachin
Tiwari, Energy Storage Technologies- An Overview, International Journal of Science, Engineering and
Technology Research (IJSETR) Volume 9, Issue 5, May 2020, ISSN: 2278 -7798 (2) Anil Kumar,Prashant
Mishra, Suresh Kumar Soni, V K Sethi, Sachin Tiwari, Future of Concentrated Solar Power in India Coupled
with 24×7 Thermal Storage. International Journal on Emerging Technologies (Scopus)- Accepted

International conferences (1) Anil Kumar, V K Sethi, Prashant Mishra, Pankaj Kumar Singh, Energy Storage
Technologies- An Overview, Aligarh Muslim University, Oct 2019. (2) Anil Kumar, V K Sethi, Solar Thermal
Plants Coupled with a Thermal Storage-a Review of Thermal Storage Options, International Conference on
Energy, Environment and Economics, August 14-16, 2018. (3) Anil Kumar, Pankaj Kumar singh, Prashant
Mishra, V K Sethi, Study On Future of Solar Thermal Storage System Using Concentrated Solar Power.

APPENDIX-B:

Thermal Energy Density Calculation for Salt Crystals Thermal energy stored in a solid mass (sensible heat)
by raising its temperature can be calculated as follows: The heat or energy storage is given by:

Q = V ρ cp dt

where,

Q = sensible heat stored in the material (J)

V = volume of substance (m3) ρ = density of substance (kg/m3) cp = specific heat of the substance (J/kg
oC) dt = temperature change (oC)

Temperature necessary to stored 300 KWh in 1 m3 of Salt

Crystals (Thermal Energy Density: 300 KWh/m3)

dt = Q/ (V ρ cp ) Q (in KWh) = Q (in KJ) /3600

(second/hour) Q (in KJ) = 3600 x 300 = 1.08 x 106 KJ

Q = 1.08 x

109 J V = 1

m3

ρ = 2200 kg/m3

cp = 870 J/kg

oC

Using the above values, we get:

dt = 565 oC

Hence we need the core temperature to rise up to 565 oC to capture and store 300 KWh/m3 of thermal

energy density. APPENDIX-C:

SOLAR POWER PLANT WITH 24X7 THERMAL STORAGE

About the

Project:- Project
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Title:

1MW el. (3.5 MW) solar thermal power plant with 16 hours thermal storage capacity for continuous operation

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Project Number:

15 /13 /2008-09/ST

Government of India, Ministry of New and Renewable Energy, Solar Thermal

Energy Group Date of commencement of the Project:

December 2010

Date of completion of the Project:

December 2016

Objectives of the

Project:-

The Objective of the project is to design, manufacture and establishment of a 1MW capacity R&D solar
thermal power plant with 16 hours storage facility based on indigenously developed and manufactured
Parabolic Solar Reflectors at an estimated solar to electric efficiency of about 12%. The configuration of
the project includes 770 no’s of 60SQM each Solar Reflectors with each having thermal storage
receivers.

Key Features of the project includes: • 770 no’s of 60SQM parabolic Reflectors with automatic dual axis
tracking mechanism with network enabled monitoring

•770 no’s of Static Thermal storage Receivers for 16 hours thermal storage for night operation

•Direct steam generation at the focus of each parabolic reflector

•6500 kgs of superheated steam generation every hour for continuous 24 hours capability

•1.2 MW el. Capacity two stage Turbine and Generator

•Fully automatic off-grid power generation as per real time

demand Output of the Project:-

a. Nature of Output:

•Peak output upto 1.2MW electric power output per hour

•Thermal storage for 16 hours for continuous operation of the plant

•Direct steam generation at focus

•Steam output with acceptable parameters from 252 Deg C to 410 DegC temperature and operating
pressure from 38Bar to 44 Bar atmospheric gauge pressure

•Total steam production of 6500 kgs per hour

b. Performance Specifications:

•60SQM Parabolic Solar Reflector:

i. Each Reflector can generate thermal energy output up to 170kwhrsper day

ii. Each Reflector can concentrate up to 1200DegC temperature at focus

•Thermal storage Receivers:

i. Each Receiver can store thermal energy up to 150kwhrs perday

ii. Direct steam generation of temperature ranging from 250DegCto 450DegC at operating pressure
from 38Bar g to 44 Bar g

•Overall plant output:

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i. The overall plant produces 7000 kgs of steam every hour for continuous 24 hours plan toperation.

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ii. Turbine – Generator can produce peak of 1.2MW of power output per hour iii. The thermal storage allows
the plant to run on continuous basis round the clock. It also allows the plant to generate power as per
demand.

c. Details of engineering design/drawing, specifications etc:

I. 60SQM Parabolic SolarReflector:

The Parabolic Solar Reflector is completely designed with space frame methodology with static load and
dynamic load analysis for dead load and wind load. The reflective are comprises of solar grade curved
mirrors covering 60SQM.

The Parabolic Solar Reflector can mainly be distinguished into four main components: 1. Supportingst and
2. Rotating wheel 3. Central bar space frame and 4. Outer frame with cross bars and long bars.

All the materials used for the design are of Mild steel grade as per IS 2062for solid M.S sections and as per IS
4923 for hollow sections.

All the surface areas are protected with epoxy paint coat and marine protection PU paint coat on the
properly cleaned surface through copper slag blasting. Main components of 60SQM Parabolic Solar
Reflector:

a. Supporting Stand: The supporting stand is grounded on the concrete foundation that acts as
load transferring component for the60SQM

Parabolic Solar Reflector. This supporting stand requires design as per the latitude of the location; hence
different revision of design is required for different locations. The base of the supporting stand is designed in
triangular shape for more stability and less land requirement. All the materials used for the design are of Mild
steel grade as per IS 2062 and M.S. sections as per IS4923.Thedesign is analyzed through space frame
design for dead load as well as wind load. All the surface areas are protected with epoxy paint coat and
marine protection PU paint coat on the properly cleaned surface through copper slag blasting.

b. Rotating Wheel: The Rotating wheel acts as connection between the supporting stand and the parabolic
frame. The wheel is rested on the supporting stand while the arms of the rotating wheel provide hinge
type anchor joint support to the parabolic frame. All the materials used for the design are of Mild steel
grade as per IS 2062 and M.S sections as per IS 4923. The design is analyzed through space frame design
for dead load as well as wind load. The daily tracking arrangement is assembled through rotating support
onto the supporting stand through rack and pinion arrangement with actuator and DC motor for daily
rotation. All the surface are as are protected with epoxy paint coat and marine protection PU paint coat on
the properly cleaned surface through copper slag blasting.

c. Parabolic Outer Frame: The third major component of the Parabolic Reflector is the parabolic frame. The
outer frame is designed in three parts as per the requirement of flexibility and rigidity balance to
accommodate various shapes of parabola’s for different seasonal requirements. This outer frame provides
hinge support to various cross-bars and long- bars that are designed to support the mirror pieces that
make a perfect parabolic reflective surface. d. Central bar space frame design: The central bar space frame
design acts as backbonesupporttotheouterparabolicframe.Thiscomponentisdesignedto serve the shape
change tracking mechanism on the longitudinal axis of the parabola. This component accommodates
three shape change mechanical actuators that are driven by DC motors through microcontroller image
processing that gives signal to the DC motors to achieve desired parabola shape. This structure through its
flexible behaviors enhances the concentration ratio of the output focus at the focal point.

e. Flexible Parabola: The structural design allows for flexibility in the structure to accommodate flexible
parabola. There are different parabolas for different seasons. These flexible parabolas are possible through
automatic dual axis tracking mechanism. There are three types of tracking:

i. Daily Tracking: This tracking mechanism allows the Reflector to track the sun throughout the day. This is
done with the help of Rack and pinion mechanism

ii. Seasonal tracking: This tracking mechanism allows the Reflector to align with the changes in the angle
of the sun due to change in the season

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iii.Shape change tracking: This tracking mechanism allows the reflector to change the shape of the
Parabola to increase the concentration ration of the focus.

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To achieve the required strength for carrying the dead load and dynamic load and flexibility for various
bending into different parabolas, the Reflector has been designed in STRAP software for space frame analysis
for different positions throughout the day. Below shown is the output of this analysis:

II. Fully Automatic Dual Axis Tracking Mechanism: All the three types of tracking are fully automatic through
combination of mechanical actuators, DC motors and image based processing with microcontroller and
programming which is from

IMA TRACK POWER was developed for the fully automated tracking of 60m² Scheffler Reflectors. Ima track
independently analyzes the focus with help of a camera module. The software performs image processing
and calculates coordinates of the centre of the focus. When the coordinates do not correspond with the
target position, actuators D1 and S4 are driven to adjust the solar reflector until the coordinates of the
focus centre correspond to the centre of the receiver window.
When centered on the receiver area, the focus size is optimized by adjusting the three shape change
actuators S1, S2 and S3 until focus losses at the receiver window are minimized. Main condition for a proper
function of the deviceis, that the receiver center is located on the rotation axis of the reflector. The receiver
temperature measurement is not provided. On over temperature condition, an alarm must be send to the
"Imatrack Plant Control (IPC)" server by the measurement devices provided by the WRST. The IPC server
shuts down the corresponding dish(es) immediately by sending corresponding messages over the wireless
network. One motor driver is used for receiver door control. The Imatrack performs tracking of sun by a solar
concentrator on the basis of the real focus position rather than on the calculated or measured sun position.
Further, the apparatus is capable to optimize size and position of focus until a maximum efficiency of the solar
system is achieved. The function principle is illustrated with reference to the accompanying drawings, with
reference numbers indicating the corresponding parts in the various figures. . As shown in figure 1, there is a
typical view of the illuminated focus area (2), the solar receiver (1) where the concentrated light is
transformed into usable energy and its surrounding, as it would be seen by the camera. Figures 2 and 3 show
the different stages of the tracking and optimization process.

The target can be reached by running several actuators at the same time, resulting in movement (4) or
with one actuator at a time, symbolized by the focus movement (5a) and (5b).

When the center (3) of the focus area (2) reached the center of the target (1) as shown in figure 2, the
reflector is deformed with the help of the actuators S1, S2 and S3 in such a way, that the focus area (2)
matches with the target area
(1) in the bestdegree possible (see figure 3) and losses are minimized.

iii.Indigenous Fabrication and manufacturing:

a. The design of the 60SQM Parabolic Solar Reflector is analyzed with space frame design methodology
for all kinds of loads and structural behaviors. This Reflector is first of it skin that uses structural steel with
average of 50kgs/SQM for its overall design basis.

b. The design is envisaged in such a way that all the required fabrication and manufacturing is
completed with local capacity building with zigs and fixtures for various components of the
Reflector.

c. Majorityofthecomponentsusedarefromtherawmaterialsthatareavailable locally in India. The fabrication

process is also localized and with semi auto-semi manual fabrication, generating employment.

d. All components are surface protected through the process that involves: Surface cleaning with copper
slag blasting; Surface protection with multiple layer protection: first coating with zinc red oxide, second
coating with two component epoxy primer coating and third layer with weather resistant marine grade
coating.

iv.In house developed curved mirrors:

e. To enhance concentration at the static focus, the mirrors used for Reflectors are solar grade mirrors with
more than 93% reflectivity and special epoxy coating to protect the silver oxide mirror coating at the
backside to extend the service life of the mirrors.

f. Each Reflector has 760 mirror pieces with five different sizes to accommodate into a parabola curvature.

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g. There are 15 no’s of different curvatures for the mirror pieces that are used to make a perfect
parabola curvature for one Reflector

h. Special glue is used for cold bending mirrors with required curvature. The
specificationoftheglueare:lowviscous,siliconsealantbase,twocomponent, fast curing, UV resistant,
adhesive glue

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v.Aperture area of Reflector and output throughout the year:

The aperture area of the Reflector is as shown in figure below changes in different seasons as per the
inclination with the polar axis.

1-

100% MATCHING BLOCK 15/16 Final Thesis_ Mohit Arora.docx

Jan-10 1-Feb-10 1-Mar-10 1-Apr-10 1-May-10 1-Jun-10 1-Jul-10 1-Aug-10 1-Sep-10 1-Oct-10 1-Nov-10

This variation in the aperture area for a 60SQM Paraboloid Reflector throughout the year is calculated with
the formula and is shown in the graph below:

60 Variaiton of Aap of SD Day of

the year 50

40

Aap(m2) 30

20

10

0 30 60 90 120 150 180 210 240 270 300 330 360 390

The thermal output from the Reflector is calculated using the aperture area of the Reflector, the Direct
normal Irradiance (DNI) and the efficiency factor of the Reflector. The efficiency factor of the Reflector
depends on various factors like Mirror Reflectivity, surface of mirror cleaned, purity and accuracy of mirror,
normally we take 60% as efficiency factor of Reflector surface. The Direct normal Irradiance (DNI) is the
actual DNI measured on the location for every 10 mins and averaged out for hour and then for the day.
So the output of Refelctor = aperture area (SQM) x avg. DNI for the day (kwhrs) x efficiency factor.

DNI Radiation in kWhr/day from avg. month 2010 The below graph shows the avg. DNI of the location for

the year 2010. 0.00 1.49 1.31 2.00 1.00 3.00 2.96 3.55 4.00 4.01 5.25 5.63 5.44 5.40 5.62 6.00 5.00 5.91

6.03 DNI… 7.00

1- De c- 10

vi.Static Cast Iron CavityReceiver:

i. Design, Detailing:

a. The Receiver is made up of monolithic cast iron material of grade FG 200 through casting process.
There is conical cavity at the centre of the solid cast iron block. This cavity has opening of 500mm at
the front face and extends upto 700mm deep into the solid cast iron block in conical design.

b. single helical boiler grade coil is wound around the monolithic conical cavity
castironbodyaroundtheperiphery;thiscoilhasinletatoneendandoutletat the other end. This coil acts as heat
transfer material from the cast iron body to the water flowing in the coil. This heat transfer enables the
water to convert into steam in the coil itself. c. Special antireflective quartz glass with 99.99% purity with
2mm thickness is used to cover the cavity opening of the Receiver in order to avoid the thermal heat losses
due to convective losses.

d. The entire body of the Receiver is covered with mineral wool Insulation of 6 inch thickness with aluminum
cladding to minimize heat loss to atmosphere. The Receiver is supported and mounted on a triangular
structure for better stability and supported with fixtures that minimize heat loss due to heat transfer.

6.1 Detailed ProjectReport

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a. Experimental works carriedout:

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First Prototype Receiver testing setup and result:

Thermal Storage Receiver Testing & Results:

i. Measuring system setup for first Prototype: The schematic diagram explains the set-up of the measuring
system to evaluate the 60m2 Paraboloidal Reflector and the static cast iron receiver. Components involved in
the Measuring system:
ii. 60 SQM Paraboloidal Reflector

4 no’s of Temperature sensors Type K embedded in the Receiver iii. Pressure sensor and temperature
sensor to measure steam parameters

iv.Campbell data logger to record the measurements (temperature and

v. Weather station (Shadow ban rado meter, Direct normal radiation DNR, Wind Speed, Wind direction, Air
temperature)

The measuring systems consist of two subsystems: Subsystem one collects the data of the receiver, while
subsystem two is the heart of the weather station, both subsystems collect data through Campbell CX
1000 data loggers Receiver system

The measuring system of the receivers consists of 4 receiver temperature sensors (type K thermocouples), a
water meter, a steam pressure sensors as well as a temperature sensor for the water and for the steam (type
K thermocouples). The water meter allows the manual reading of the water flow and the amount of water
injected into the receiver. The data is collected with a Campbel lCX1000 data logger. The pressure sensor is
from Siemens pressure transmitter of required pressure range. Following are the results obtained from the
tests carried out with below setup: The thermal behavior of the Receiver without front glass The testing was
carried out in the month of May 2011 with the measuring set-up as shown in Fig.4. The Static receiver is
charged during the day time through the solar rays’reflection focus from the Paraboloid reflector.

The Receiver is charged without front glass

covering. Observation:

i. Max. temperature reached – 400Deg.C

Illustrates the thermal behavior of the Receiver without front glass

The thermal behavior of the Receiver with front glass cover at Receiver opening

Observation:

i. Max. temperature reached – 450 Deg. C

Illustrates the thermal behavior of the Receiver with front glass cover at Receiver opening The thermal behavior
of the Receiver with front glass covering at the receiver opening and with water flow through the heat transfer
coil

Observation:

i. Flow rate of water through the heat transfer coil – 3.5litrs/min. ii. Max. temperature reached at the Receiver
– 450Deg.C
iii. Max. pressure of steam discharged – 42bar iv. Max. temperature of steam discharged – 430Deg. v.
Discharging 2/3rd of time superheated steam and 1/3rd of time saturated steam before rapid temperature
drop.

Illustrates the thermal behavior of the Receiver with front glass covering at the receiver opening and with
water flow through the heat transfer coil –

The thermal losses in the Receiver with time

Illustrates thermal losses in the Receiver with

time

b. Detailed analysis of report–

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i. Simulation report of thermal behavior of 5 no. of Receivers in series:

Simulations were done in the ‘colsim’ simulation environment, for the cast iron receiver in series connection
to determine the thermal behavior pattern and to determine the thermal storage duration for further simulation
of the plant:

Following observations and assumptions were considered in the simulation of 5 receivers in series:

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•The functioning of the Receiver model considered for simulation has been matched and the parameters
of the Receiver model were adapted to fitthe actual results obtained from testing the first proto type receiver
• In this simulation receivers with equal mass in series of 5 no’s is considered

•Actual averaged Weather data for three years is considered for the timeframe used in this simulation report

•Various other assumptions for mass flow rate of fluid (in this case water), with receiver front glass position
are studied for thermal storage behavior.

•The max. mean temp. achieved by charging the receiver is assumed as500DegC, while the minimum
temp till discharge the receiver is assumed as 260DegC.

•The receiver geometry is idealized to cylindrical structure geometry and is divided into equally spaced
different subsections of the cylinder representing different temperature gradients along with the length of
the heat transfer coil.

•The incoming radiation, the absorbed radiation, the heat transferbetween different subsections and the
heat transfer coil, the ambient losses are all considered and matched in the simulation results according to
the actual achieved test results of single proto type receiver. To summarize, the assumptions in this study
are:

•One-dimensional heat transfer.

•Constant heat conduction coefficient for cast iron (line a system).

•Every node has same amount of volume.

•Numbers of turns in helix are equal to the number of nodes.

•Reflections inside the cavity are neglected.

•There is no temperature gradient from cavity to outside diameter of the cylinder.

•Thermo physical properties of fluid are same at every point inside the specified pipe section.

•Storage is composed of a cylindrical block of cast iron. To analyse the heat transfer between the cast iron
nodes, the block is divided to 20 cylindrical shaped nodes. • The heat exchange pipe is a helically coiled tube,
cast inside the cast iron block. To analyse the heat transfer between the fluid passing inside the pipe, and the
iron; the block is assumed to be unwind (see figure below) and divided into nodes.

Results for the temperature distribution in the storage under specific operation temperatures are presented
the figure below. Shown is the behavior of five Receiver- Storage units (R/S) which are interconnected in
series to one module. The thermal behavior of this module and its components is simulated over a period
of three subsequent days.

In the figure above, different nodes of each receiver are depicted by the shading and the different
receiver/storages by the different colors. From the graph, it is evident that the temperature drops first in R/S 1
and last R/S 5. The simulation model, contains a controller, which is operating the module according to certain
rules which need to be defined beforehand. In the shown simulation, the controller was set to (i) not allow the
temperature of the storage exceed a temperature of 500°C, (ii) to start
dischargingonlyifaminimumtemperatureof300°Cisreachedinthemoduleand(iii) for the discharging to start only
after nightfall. (iv) The discharging then stops for the night when a minimum steam temperature of 300°C is
reached.

Controller settings:

The operating controls thus far are set to temperature limits in the system such as minimum/maximum
steam temperature, minimum/maximum storage temperature and whether or not it is day or night (only
night time discharging was allowed here). The operation of the hydraulic cycle in the simulation is controlled
by a controller, which is described by a set of controller parameters. In the figure below the control
parameters for the simulation are summarized.

The maximum temperature which a storage node is allowed to reach is set with this value. When, during the
course of the day, a receiver/storage node (usually the node at cavity opening – Receiver outlet) reaches this
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temperature, the cavity opening closes and no more radiation enters the receiver until the temperature has
fallen below the safety threshold temperature, either because discharging has taken place or the temperature
has fallen due to thermal losses. (The corresponding controller parameter is PAR1: Max. Cavity Opening Node
Temperature). Controller settings for this simulation:

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Only parameters varied throughout this report are stated below: PAR1 Max. cavity NODE temperature
500°C PAR3 Min steam temperature 280°C PAR5 Mass flow rate 80 kg/h PAR6 Steam pressure 42 bar

PAR7 Feed water temperature 80°C PAR9 Daily rotation angle span 160° Weather data used: original
Meteonorm data.

The assumption applied in charging and discharging philosophy for the simulation of Receivers in series: In
the following graph, different cycles and phases during the

day and the charging and discharging sequence (according to the above controller settings) are described in
more details, here shown is the daily cycle of the last receiver in series in a module

Signal A: maximum storage temperature reached – action - close the cavity opening Signal A1: Storage
temp. will not increase over limit Signal B: Sun has set - action - close the cavity opening, start discharging
Signal C: max. module temperature or quality reached – stop discharging Signal D: Sunrise the next day –
action – open cavity opening of Receiver The solid orange line in the picture above indicates temperature of
the Receiver body at the front portion of the Receiver; The Green line in the picture above indicates
temperature of the Receiver body at the back portion of the Receiver.

Heat Loss and Radiation for different Receivers in a module: Figure shows the heat losses to ambient (Q_loss,
upper graph) and the heat gain through absorbed radiation (Q_rad, lower graph) of the first and last receiver
in a module. The heat loss in the last receiver is significantly higher (almost by a factor 2) than the loss of the
first receiver due to the lower average temperatures of the first Receiver. The first Receiver can accept upto
35% more incident radiation (as compared to the last receiver) until the overheating protection requires to
cover the Receiver door.

Le8: Thermal losses – heat losses Le9: Thermal input – heat gained Orange curve – is for first Receiver in
Series Green Curve – is for last Receiver in series

ii. Simulation report of thermal behavior of 10 no. of Receivers in series:

Simulations were done in the ‘colsim’ simulation environment, for the cast iron receiver in series connection
to determine the thermal behavior pattern and to determine the thermal storage duration for further simulation
of the plant: Following observations and assumptions were considered in the simulation of 15 no’s of
receivers in series:

•The functioning of the Receiver model considered for simulation has been
matchedandtheparametersoftheReceivermodelwereadaptedtofittheactual results obtained from testing
the first proto type receiver

•In this simulation receivers with equal mass in series of 15 no’s is considered

•Actual averaged Weather data for three years is considered for the timeframe used in this simulation report.

•Various other assumptions for mass flow rate of fluid(in this case water), with receiver front glass position
are studied for thermal storage behavior.

•The max. mean temp. achieved by charging the receiver is assumed as500DegC, while the minimum
temp till discharge the receiver is assumed as 260DegC.

•Thereceivergeometryisidealizedtocylindricalstructuregeometryandisdivided into equally spaced different

subsections of the cylinder representing different temperature gradients along with the length of the heat
transfer coil.

•The incoming radiation, the absorbed radiation, the heat transfer between different subsections and the
heat transfer coil, the ambient losses are all
consideredandmatchedinthesimulationresultsaccordingtotheactualachieved test results of single proto type
receiver.

Adaptions of receiver model:

Two measures have been taken:

I. To account for the higher mass of the receiver, the density value of their on material was scaled

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according to: density_new = density * mass_new / (3900 kg)

A value of 4100 kg as mass for the new receiver was used.

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II. The new geometry and increased insulation thickness of the new receiver will
resultinreducedheatlossesthroughtheoutersurfaceofthereceiver(surface
withoutthecavityface).Fromgeometrydataandinsulationthickness,arough
estimationresultedinareductionofheatlossby30%.Therefore,the heat loss through the outer surface of
the receiver was scaled by a factor0.7 Controller settings for this simulation:

The temperature control mechanism was rediscussed and finally it was concluded to deactivate the closing of
Receiver door. In consequence, in the simulation model, an overheating of receivers is allowed and more heat
can be extracted. It was further agreed
nottoimplementadaytimedischargeatthispoint,buttoneglectminordifferences(mainly the slightly higher heat
losses if no daytime discharge is allowed but instead the receivers may overheat) arising from this
simplification in the simulation. A crosscheck with the Ima track settings revealed that the assumed 140°
angle span (see previous case) was still overestimated. The actual value is 130° and this value was used.

Only parameters varied throughout this report are stated below; parameters varied w.r.t. the previous
simulations are indicated by bold cursive letters:

PAR1 Max. AVERAGE storage temperature 900°C (deactivated) PAR3 Min steam temperature 260°C PAR5
Mass flow rate 240 kg/h

PAR6 Steam pressure 44 bar

PAR7 Feed water temperature 105°C PAR9 Daily rotation angle span 130° Weather data used: downscaled
Meteonorm data. Mass of all receivers: constant, 4100 kg

Simulation results: To quickly give an indication on the effect of higher masses, reduced heat loss.

Only a short period of time of 12 days of January has been simulated. The variability of results is shown in
the figure below. From this we conclude that we may choose the day Jan 7 as representative ‘good day’ for
this month. The detailed evaluation and comparison of cases is done only for this day and presented in
the following. Below table Accepted radiation, thermal losses and thermal gains of all receivers (1 – 15) in the
module (for Jan 7) and their relative contribution to the total radiation / loss / gain of the module. All receiver
masses are equal, 4100 kg. . Equal distribution would be a contribution of 6.7 % (1/15 %) for each receiver.

Daily average Thermal output simulation result for module with 15 Receivers in series:

To depict the performance of Receivers in the module, the daily average contribution of the
Receivers/storages is plotted for each month in the following figure:

Figure shows Average Receiver daily thermal output for each month with 240kg/hr mass flow with 15 no’s
of Receivers in series of 4100 kg mass per Receiver

iii.Conclusions derived:

•From the temperature evolution across the modules over time, it can be noted that, during discharge the
temperature of the ‘latest’ receivers in a module decrease only in the final stage of the discharging period. •
Continuous 24 h operation possible due to thermal storage.

•Cost effective operation, thanks to direct super heated steam generation, no heat exchanger, no heat
transfer fluid and low parasitic loads

•Less fabrication and maintenance complexity due to fixed static receiver with no need for flexible high
pressure joints

•Decentralized storage system increasing the operational flexibility and reducing the vulnerability present
with central storage systems • Local manufacturing, cost effective design

•Easy to operate and low maintenance cost.

c. Testing works carried out:

After the successful testing of the first prototype Receiver in May 2011 and conducting simulations
through the simulation software “Colsim” simulation environment for both single receiver as well as 5no’s
of Receivers in series and subsequently15no’s of Receivers in series as discussed above; it was clearly

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evident that we shall go for monolithic cast iron receiver around the conical cavity from all the three sides,
with proper insulation to minimize the thermal losses.

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Accordingly, the testing set-up was set for practical testing and measurements to further explore different heat
transfer design concepts and to confirm the results seen in the simulation results for 15 no’s of Receivers in
series. Here below, we share the testing results for all the testing works carried out in two phases:

1.Single monolithic cast Iron cavity Receiver with different heat transfer design concepts 2. 10 no’s of
monolithic cast iron receivers in series with different mass flow rates

i. Testing results for single monolithic cast Iron cavity Receiver with different heat transfer design

concepts: Temperature sensors detail:

Temp EF – Temp east front, Temp EB – Temp east back Temp WF – Temp west front, Temp WC

– Temp west center, Temp WB – Temp west back

Only temperature west center thermocouple was inside the 25mm casting

Insulation – 200 mm insulation (25 mm ceramic wool 128kg/m3 + 25mm ceramic wool of 96kg/m3 +
150mm LRB wool) L25 receiver graph (charging-discharging)

Figure shows the charging-discharging pattern of L25 receiver from 2ndDec2013 to 8thDec2013. It can be
observed from the above graph that the duration from 2nd Dec 2013 to 8th Dec 2013 do not have same
solar radiation. Therefore there is variation in the peak temperature reached while charging. It can also be
observed that the Receiver have been successfully discharged every day to the minimum temperature
average of around 260Deg C.

L31 Receiver features ‘Receiver with heat transfer paste:

- Conical cavity receiver - Weight – 3710kg - Length – 1meter - Coil length – 31meters, - Coil Pitch – 75
mm. Coil is wrapped around the casting, heat transfer paste was applied to fill the gaps between cast Iron
block and coil. - Temperature sensors detail: Temp EF – Temp east front, Temp EB – Temp east back

Temp WF – Temp west front, Temp WB – Temp west

back L21 Receiver features ‘Receiver with grooving’:

- Conical cavity receiver

- Weight – 3610kg

- Length – 1meter

- Coil length – 31meters,

- Coil Pitch – 75 mm. casting was machined to have groove made of the exact size of the coil diameter,
coil was fitted inside these grooves. (Photo 4, Photo 5)

- Temperature sensors detail: Temp EF–Temp east front, Temp EB–Temp east back Temp WF – Temp
west front, Temp WB – Temp wes tback

ii. Testing results for 10 no’s of monolithic cast Iron cavity Receiver with different mass flow rates: In total,
10 no’s of monolithic cast Iron cavity Receivers were connected in series namely L-22, L-23, L-24, L-25, L-
26, L-27, L-28, L-29, L-30 and L-31; the first Receiver in series was L-31 and the sequence was in
diminishing numerical order to last Receiver was L-
22. A dedicated piston pump was connected to the inlet of the first Receiver. Each Receiver had four
Thermocouples for measurement of body temperature of the Receiver

and one Thermocouple to measure the steam temperature at the outlet of each receiver as shown in the below

figure. Following parameters are measured with the following instrumentation and controls:

The four temperature sensors in each Receiver body are named based on the location and direction on
the Receiver body, for example: For Receiver L-31 if the thermocouple is installed on front side of the
Receiver near cavity opening and if it is on the east side it is called L31_TempEF (East Front) accordingly all

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the four thermocouples are named accordingly:

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TempEF – East Front; Temp EB – East Back; Temp WF – West Front; TempWB – West Back The
Thermocouple that measures the steam temperature is called T_Steam The reading of the temperatures
are logged through data loggers into the DAT file on every minute basis, which is then transferred to MS
Excel and temperature is averaged on hourly basis which is then referred as L31_Temp EF_Avg of that
thermocouple. Further if all the four thermocouples attached to the body of the Receivers are averaged then
the respective temperature reading is called as L_31 Avg Body T.

The 10 Receivers are connected in series withL-31 as first Receiver and L-22 as last Receiver in series. The
series connection is such that the output of first Receiver shall become the input of second Receiver and
soon. Therefore, it is observed that the first Receiver is always at lower temperature ranges than the last
Receiver, since the first Receiver receives DM water at ambient temperature. The temperature is gained by
the fluid, in this case DM water, through heat transfer and is passed on to next Receiver in series.

The testing was conducted in the month of March 2014, starting from 3rdMarch 2014 till 24thmarch 2014
to observe and measure various parameters under various solar radiation
inputs.Anobservationsheetwaspreparedtomeasuretherelevantparametersandlogthe observations in the
following manner as shown in the figure. These observations and readings were analyzed according to
therelevance.

As can be clearly observed from the below graph the receivers have higher body temperatures as per the
series sequence from L-31 (1st) to L-22 (last) Receiver in series:

A similar group behavior can be observed in the steam temperatures of Receivers in series as per the series
sequence from L-31 (1st) to L-22 (last) Receiver in series:

The steam achieves superheated steam temperature as it passes from first Receiver L-31 from peak of 150
Deg C to the last Receiver L-22 of 450 DegC peak in series.

It can also be observed that the 10 no’s of Receivers in series could discharge upto17 hours of saturated
(280 Deg C) and superheated steam (380 Deg C) continuously with average mass flow rate of 98 litres
/hour on 7th March 2014. It is observed that the basic parameters required to run a steam turbine @ 42 bar
pressure with temperature range from 252DegC to 410 Deg C can be achieved as per requirement from the
above kind of setup.

The group behavior pattern of 10 Receivers in series can be observed from the below shown graph; here it
can be clearly seen that discharging pattern follows uniform and gradual linear behavior trajectory as
anticipated.

The discharge of the module started at 12:15 P.M and discharge was completed by 5:15 A.M. The solid
graphical lines depict body temperature of the module while the dotted graphical lines depict steam
temperature of the module with each receiver scaled on X- axis starting from first receiver L-31 to the last
Receiver L-22. The difference in temperature from Discharge start to discharge finish can be observed as
difference between two lines (solid lines for body temp and dotted for steam temperature).

d. Work carried out: i. Process Flow Diagram for India One solar plant:

The plant operates on Rankine cycle principle. The Parabolic Reflector concentrates the solar radiation
towards the in- house developed, highly efficient cavity receiver. The cavity of the Receiver which is made of
monolithic cast iron acts as perfect black body and thus provides excellent thermal storage. The boiler grade
coil around the body acts as a heat exchanger which allows for water to exchange heat and convert into
steam.

The thermal storage can be operated between 250 Deg C to 550 Deg C and can be discharged on demand.
The steam generated is mostly superheated steam and the rest is saturated steam at operating pressure
from 38Bar to 44 Bar gauge pressure.

The total field is divided into 23 no’s of modules. Each module has receivers connected in series and each
module has been named with an alphabet starting from ‘A’ from the North to ‘W’ to the south; the number of
Receivers ranges from 20no’s to 45no’s as per the availability of the space. The output of all the modules is
connected to the steam header that carries steam to the steam turbine.

The plant is designed as a captive plant (off grid) as per demand to provide electricity to the headquarter
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campus Shantivan at Abu Road, Rajasthan.

ii. Typical P&ID of a solar module from ‘India One’ solar power plant:

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A typical module consists of multiple cast iron cavity Receivers in series, the no’s of Receivers in series
depends on the layout and land availability. The no. of Receivers ranges from minimum 13 no’s to max.
45 no’s in series, each module (each row) is given A alphabet for identification starting from ‘A’ from the
north of the layout to ‘W’ ending towards the south of the layout. Each module is aligned in exact east-west
direction facing south and receiving solar radiation on the reflective surface. The numbers of Receivers in
series for each module is given in the table here below:

The below figure shows the layout of the solar thermal field with nomenclature for the modules from
Module A to Module W for each row and numerical from1to45 for each column. So, each Reflector shall be
numbered, as for example, ‘A-34’ which indicates the Reflector is placed in Row A and column 34.Each
module is connected to a piston pump at the inlet to the first Receiver in series and the outlet of the
module, the last Receiver in series is connected to a common steam header that collects the steam
generated by each module and carries the total steam generated by the solar thermal field to the Turbine.
The below flow diagram shows the Basic P&ID diagram
foratypicalsolarthermalmodulewithcompletecyclethroughcondenserandbackto the solar field through de-
aerator.

Basic P&ID diagram for a typical solar thermal module

Since there are 23 no’s of modules in the field, therefore there are also 23 no’s of piston pumps (positive
displacement pumps), i.e.: one pump per module. Each module acts like a boiler that delivers superheated
steam to the steam header. The first 35% of Receivers in series in a module act like economizer that heats up
water into steam, the next 35% of Receivers in series in a module act to generate saturation steam and the
last 30% of Receivers act like super heaters to generate superheated steam which is then finally connected to
the steam header. The required operating pressure of steam is delivered by piston pump at the inlet of the
module. The mass flow rate of the pump is controlled by VFD (variable Frequency drives) that take their input
signal of operation from the centralized pressure control mechanism which in turn takes signal throughout put
frequency of generator. The plant is off grid connected to the Brahma kumaris campus that has load demand
that can cater to 25,000 people for lodging and boarding. Hence, the load demand is indirectly transferred to
the VFD of the pumps which synchronizes the demand with the supply and accordingly varies the mass flow
rate of the water which then converts into steam and goes to the steam turbine. The mass flow rate for each
module is programmed as per the length of the module i.e. number of Receivers in series for the module. The
bigger the modules the bigger is the flow rate through it. In this way, the complete solar thermal field with
each module has synchronized thermal behavior of charging and discharging. Each module is installed with
analog as well as digital instrumentation that reads the important parameters related to pressure,
temperature. Also, each module is treated as a boiler and accordingly, each module is having dedicated safety
valve. Also, the module is equipped with strainers, Isolation valves and Non-return valves wherever necessary
for smooth operation and maintenance. All modules have common water header on inlet side and common
steam header on the outlet side. Thus, the modules derive water from the common water header and supply
steam generated to the common steam header. The steam header is almost 400 meters long pipeline
equipped with strainers, isolation valves and steam traps and drain taps wherever necessary. The entire steam
header is designed as per detailed stress analysis for higher temperature range up to 450 Deg C. accordingly,
necessary expansion loops have been provided throughout the length of the steam pipe line where necessary
as per design. All the steam pipe line is designed as per Design and construction code IBR 1950 with latest
amendments. The material used for steam pipeline is of two different grades namely carbon steel A106 grade
B for saturated steam and alloy steel P11 grade for super heated steam.

Pressure Control scheme for the solar thermal field to generate required quality and quantity of steam to
Turbine:

The steam Turbine allows certain quality of steam for its functioning it requires steam of
pressurerangingfrom38BarG to 44 Bar Gand temperature ranging from 252 Deg C to 410 Deg C. And
minimum quantity of steam starting from 4000 kgs to 6500 Kgs. Therefore it is very important that the solar
thermal field generates steam of the required quality and quantity of steam. In order to derive this steam
form the solar filed, PID logic is implemented in the control logic that ensures the requirement. The
scheme is shown in the following diagram:

iii.P&ID’s of various sub systems:

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iv.Technical Datasheet of Turbine and Generator: P&ID for Turbine (Two

stageTurbine): Operating Parameters for Turbine :

Operating data and limit value

Operating data and limit value

(Turbine1)

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Operating data and limit value (Turbine2)

Technical Datasheet for Generator (AVK) :

Technical Datasheet of Condenser:

Operation parameters and Results:

Theprojectiscommissionedintwophases–firstphaseiscommissionedinNovember2016 with 300 no’s of

Reflectors commissioned, which is the minimum number required to generate quality steam for steam
turbine tooperate.

The second commissioning is completed in May 2017 withall770no’s of Reflector modules

commissioned. The project started in full potential from October 2017 with good solar radiation period.
Soon after the complete commissioning of the plant with all the sub- systems stabilized to its full potential,
the plant achieved record power generation for
maximumnumberofhoursofoperationwithoutanyhalt.Therecordmilestonefortheplant running for
continuously 42 hours without interruption / stoppage from25th December 2017 morning to 27th
December 2017 early morning was achieved soon after commissioning.

Anothermilestoneachievedbytheplantofthepeakoutputgeneration.Themaximumpeak output delivered by the

plant till date is 920 KW. Please see here below the screen shot of the peak output delivered by the plant

Solar & Thermal BenefitsAccured:

a. List of Technical documents prepared:

1.Output estimation and consideration for field layout

basedon solar radiation data at “India One” – by Heike

Hoedt – JULY 2011 :

Following research aspects are discussed and achieved in this report:

1.This report establishes the output achieved by the solar reflector wrt the solar radiations data received at
“India One” 2. This report elaborates the mathematical model done to establish the total numbers of solar
reflectors with desired output wrt to the solar radiations data received at “India One” 3. Establishment of
adequate numbers of standing and lying solar reflectors to match the climate based output variations to
achieve the required output in the best possible way

2. Consideration of Field layout based on simulation of shadowing effect at “India One” – by

Heike Hoedt - November2011: Following research aspects are discussed and achieved in this
report:

1. A model of 1:80 was used to study the shadow effect on the probable field layout of 60m2 solar reflectors 2.
Setup of only standing reflectors was developed and considered 3. Grid size with adequate distance was
determined using the shadow effect on the reflectors at various timings during the sunlight 4. Piping losses
were evaluated against shadow losses. Conclusion smaller grid of 11mx13m is recommended 3. Design &
Installation of 60m2 Parabolic Dish and Receiver
/Storage at “India One” – by Wolfgang Scheffler – October2011: 1. All aspects of design for 60m2 solar
reflectors are discussed and established 2. Basic aspects of Receiver design are discussed andestablished

Output estimation and consideration for field layout

basedon solar radiation data at “India One” – by Heike

Hoedt – JULY 2011 :

Following research aspects are discussed and achieved in this report:

3. This report establishes the output achieved by the solar reflector wrt the solar radiations data received at
“India One” 4. This report elaborates the mathematical model done to establish the total numbers of solar
reflectors with desired output wrtto the solar radiations data received at “India One” 5. Establishment of
adequate numbers of standing and lying solar reflectors to match the climate based output variations to
54/35
achieve the required output in the best possible way

4. Consideration of Field layout based on simulation of shadowing effect at “India One” – by

Heike Hoedt - November2011:

Following research aspects are discussed and achieved in this report:

1. A model of 1:80 was used to study the shadow effect on the probable field layout of 60m2 solar reflectors
2. Setup of only standing reflectors was developed and considered 3. Grid size with adequate distance was
determined using the

55/35
shadow effect on the reflectors at various timings during the sunlight 4. Piping losses were evaluated against
shadow losses. Conclusion smaller grid of 11mx13m is recommended

5. Design & Installation of 60m2 Parabolic Dish and Receiver /Storage at “India One” – by Wolfgang Scheffler
– October2011: 1. All aspects of design for 60m2 solar reflectors are discussed and established. 2. Basic
aspects of Receiver design are discussed andestablished.

6. Design options for the mirror mounting at “India One” – by Heike Hoedt – March2012: 1. Various design
options for the mirror mountings are developed and established. 2. Final design for the mirror mounting
concluded based on the most cost optimized design solution.

7.Design and Installation of a measuring system to evaluate the 60m2Parabolic dish and Receiver Storage at
“India One” – by Thorsten Ludwig – May2012: 1. Setting up of Measuring system to evaluate the 60m2
Parabolic dish and Receiver Storage using various Instrumentation set up comprising of thermocouples and
data loggers with process piping and Instrumentation required. 2. Output of the Receiver with various flow
rates and at various solar radiations with various position of the receiver (door open / door closed) was
studied and conclusion was derived for output and efficiency of the Receiver. 3. Thermal losses of the
Receiver were evaluated under different conditions. Upto 82% of solar radiations are absorbed by the Receiver
(loading efficiency), up to 65% of the overall efficiency was observed.

7.Experimental Investigation of Heat transfer between cast Iron gri tand various mixtures at “India One” – by
Atul Singh – June2012: 1. Investigate heat transfer characteristics of CI Grit and various mixtures 2. Found
an optimum mixture of CI Grit with other materials.

8. Report on test performed on Modified Receiver at “India One” – by Atul Singh – June July 2012: 1. Output
of the Modified Receiver with various flow rates and at various solar radiations with various position of the
receiver (door open / door closed) was studied and conclusion were derived for output and efficiency of the
Receiver.

9. Control System for “India One Solar Power Plant” – by Jurgen Holstein – March2011: 1. Centralized
tracking, monitoring of the solar reflectors from central control room 2. Discharging of the receivers
through the centralized network according to the pumping philosophy 3. Monitoring and control of the
Turbine and Generator

4. ntralized monitoring and control of the Balance of plant 5. Initial Power requirement to start and restart of the
India one plant 6. Power consumption monitoring, Controls and Alarm transmission system on the power
evacuation side of the plant 7. Multiple operational central and operation management system

10. Report on the Controls of tracking the 60m2 solar reflector and alerts from the central controller at India
One – by Jurgen Holstein – March2011

“India One” simulation results – module of 15 receivers in series – by Fraunhofer ISE – March2013

1. A Module of 15 Thermal Storage Receivers in series was simulated. 2. Thermal behavior of the first Receiver
and the last Receiver in series is studied in detail. 3. Thermal losses and the Thermal efficiency of the first and
the last Receiver are quantified. 4. Total average thermal energy output of single Receiver is quantified from the
simulation

11. “India One” – Modular testing & analysis of solar Receiver with storage to study the thermal behavior for
round the clock operation – by WRST Team – April2014

1. A Module of 10 no’s of Thermal Storage Receiver in series was tested and analyzed. 2. Total average
thermal output from 10 no’s of receivers in series for continuous 18 hours was documented 3. Total
average thermal energy output of single Receiver is quantified and documented from the test results. 4.
Thermal behavior of the first Receiver and the last Receiver in series results were analyzed and documented.
5. Thermal losses and the Thermal efficiency of each receiver was analyzed and documented

12. Power Consumption for fully automatic tracking system on 60sqmparaboloid Reflector – by
WRST team – August2014 1. Power consumption without optimization for fully automatic tracking
system on 60 sqm paraboloid Reflector is tested and documented. 2. Optimization frequency for the
fully automatic tracking systemon 60 sqm paraboloid Reflector is concluded. 3. Required sizing for
the power convertors from AC to DC was analyzed and concluded for further detail engineering.
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13. Network requirements for 770 no’s of fully automatic tracking system on 60 sqmparaboloid
Reflector – by WRST Team – August2014

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1. Various options for networking were studied, tested, analyzed like Wireless / Wired networks 2. Cost
implications and cost optimization with all options was studied and concluded. 3. Detail BOQ for the total
plant of 750 no’s of fully automatic tracking system on 60 sqm paraboloid Reflector layout was worked out
and documented.

b. Manpower trained under the project:

In May, 2014 the World Renewal Spiritual Trust was awarded with an assignment of Development of
Awareness Cum Training Centre on Concentrating Solar Thermal (CST) Technologies under UNDP-GEF
Assisted Concentrated Heat Technologies Project,

100% MATCHING BLOCK 16/16 manuscript final (full with tables and figures ...

the Ministry of New and Renewable Energy, Government of India.

The CST Center is located at “India One” Solar Thermal Power Plant, Brahma Kumaris, Shantivan Campus in
Abu Road, Rajasthan

Objectives of the CST Center:

•to create awareness among various groups of stake holdersfrom industries, institutions& commercial
establishments through

•end user seminars

•manufacturing workshops

•technology demonstration

•to help generating proposals for installations of CST based systems at their establishments • to support
the capacity building of CST manufacturers and entrepreneurs quality standards in CST especially of mirror
reliability, durability, performance improvements. Manufacturing skills, customization of end user products
/systems etc. Scope of Activities:

•9 seminars for potential beneficiaries from industries, institutions& commercial establishments • 6 training
programs in Scheffler technologies for manufacturers. Trainees will be exposed also to other
technologies • Around 500 no’s of stakeholders from industries, institutions & commercial establishments
took part in the Seminars and Training programs and were trained towards the CST technology for design,
development, manufacturing and end use applications.

Apart from this, around 300 personnel (skilled manpower) have been trained for installation,
commissioning, operation and maintenance of the “India One” solar plant.

132

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Hit and source - focused comparison, Side by Side
Submitted text As student entered the text in the submitted document.
Matching text As the text appears in the source.

1/16 SUBMITTED TEXT 177 100% MATCHING TEXT 177 WORDS

WORDS
molten salt storage systems are the established
Molten salt storage systems are the established commercially available concept for solar thermal
commercially available concept for solar thermal power plants. Due to their low vapor pressure and
power plants. Due to their low vapor pressure and comparatively high thermal stability, molten salts
comparatively high thermal stability, molten salts are preferred as the heat transfer fluid and storage
are preferred as the heat transfer fluid and storage medium. However, due to pricing pressure, the
medium. However, due to pricing pressure, the development of alternative, more cost-effective
development of alternative, more cost-effective concepts is an important step in making thermal
concepts is an important step in making thermal energy storage more competitive for industrial
energy storage more competitive for industrial processes and solar thermal applications [1,2]. A
processes and solar thermal applications [17, 18]. A closer look at the capital cost distribution of two-
closer look at the capital cost distribution of two- tank storage systems, reveals that indirect systems
tank storage systems, reveals that indirect systems with a maximum operating temperature of 400 °C
with a maximum operating temperature of 400 °C have differing heat transfer fluids (HTF) and storage
have differing heat transfer fluids (HTF) and storage media. For those systems, the molten salt storage
media. For those systems, the molten salt storage media (about 35 % of the direct capital costs) and
media (about 35% of the direct capital costs) and the storage tanks (about 24 % of the direct capital
the storage tanks (about 24% of the direct capital costs) are the main bearers of cost. For direct
costs) are the main bearers of cost. For direct systems with operating temperatures up to 560 °C,
systems with operating temperatures up to 560 °C, using molten salt as the HTF and the storage
using molten salt as the HTF and the storage media, the capital cost ratios are 34 % for the
media, the 0000000capital cost ratios are 34 % for storage media and 31 % for the storage tank,
the storage media and 31 % for the storage tank, respectively[3].
respectively [19],

https://www.researchgate.net/publication/311003069_Thermal_Energy_Storage_in_Molten_Salts_Overvie
...

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This paper also summarizes the investigation and analysisThis paper also summarizes the investigation and analysis of

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thermal energy storage technologies and the factor which thermal energy storage system design methodologies and
energy storage

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 4/16 SUBMITTED TEXT 21 WORDS 86% MATCHING TEXT 21 WORDS

Fernandez-Garcia,
Fernandez-Garcia, A., Zarza, E., Valenzuela, L., (2010). Parabolic-trough A,collectors
solar Zarza, E, Valenzuela, L, Perez, M. Parab
and their applications.
Renew Sust Energy Rev 14, 1695-1721. 5.

https://
...

5/16 SUBMITTED TEXT 23 WORDS80% MATCHING TEXT 23 WORDS

Morin, G., Dersch, J., Platzer, W., (2012). Comparison ofMorin G, Dersch J, Haberle A, Platzer W, Eck Comparison linea
Solar Energy 86, 1-12. 6.        & nbsp;power plants', Solar Energy,

https://archive.org/stream/KeithLovegroveWesSteinConcentratingSolarPBookZZ.org/[Keith_Lovegrove,_ ...

6/16 SUBMITTED TEXT 18 WORDS96% MATCHING TEXT 18 WORDS

A comparative study between parabolic trough collector A comparative study between parabolic trough collector an

https://lutpub.lut.fi/bitstream/handle/10024/103063/Master%20s%20Thesis_Elina%20Hakkarainen.pdf?s ...

7/16 SUBMITTED TEXT 23 WORDS76% MATCHING TEXT 23 WORDS

Giostri, A., Binotti, M., Silva, P., (2012). Comparison of two

Giostri,
linear A.;
collectors
Binotti,in
M.;
solar
Silva,
thermal
P.; Macchi,
plants:
E.;parabolic
Manzolini,
trough
G. 2011
versus Fresnel. Journal of plants: parabolic trough vs Fresnel. Proceedings of

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8/16 SUBMITTED TEXT 32 WORDS79% MATCHING TEXT 32 WORDS

Ho, C.K., Iverson, B.D., (2014). Review of high-temperatureHo, Clifford K.; Iverson, Brian D. 2014. Review of high- cent

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 9/16 SUBMITTED TEXT 18 WORDS100% MATCHING TEXT 18 WORDS

Development of solid particle thermal energy storage for Development

concentrating of
solar
Solid
power
Particle
plants
Thermal
that use
Energy
fluidized
Storage
bedfor C
technology”, Technology

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electrical energy storage technologies and the applicationElectrical Energy Storage Technologies and the potential in

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84% MATCHING TEXT 56 WORDS
WORDS

Price H. Two-tank molten salt storage for parabolic

Price, (2004), “Two-tank molten salt storage for
trough solar power plants. Energy, vol. 29, no. 5–
parabolic trough solar power plants”, Energy
6, 2004, pp. [2] Relloso S and Lata J. Molten Salt
29;883-93. 18. S. Relloso, J. Lata, (2011), “Molten
Thermal Storage: A Proven Solution to increase
salt thermal storage: A proven solution to increase
Plant Dispatchability.
plant dispatchability experience in Gemasolar tower
Experience in Gemasolar Tower Plant. Solar Paces,
plant”, Solar paces. 19.
2011. [3]

https://www.researchgate.net/publication/311003069_Thermal_Energy_Storage_in_Molten_Salts_Overvie
...

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Thermal energy storage in molten alts: Overview of novelThermal Energy Storage in Molten Salts: Overview of concept

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Design of packed bed thermal energy storage systems Design of packed bed thermal energy storage systems for
forhigh-temperature industrial process heat”, high-temperature industrial process heat

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 14/16 SUBMITTED TEXT 29 WORDS97% MATCHING TEXT 29 WORDS

Avila-Marin., (2011), “Volumetric receivers in solar thermalAvila-Marin, AL. Volumetric receivers in solar thermal power

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...

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Jan-10 1-Feb-10 1-Mar-10 1-Apr-10 1-May-10 1-Jun-10 1-Jul-10 1-Aug-10 1-Sep-10 1-Oct-10 1-Nov-10

Final Thesis_ Mohit Arora.docx

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the Ministry of New and Renewable Energy, Government of India.

manuscript final (full with tables and figures).docx

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 ANALYSIS AND OPTIMIZATION OF
SOLAR THERMAL PLANT WITH
24×7 THERMAL STORAGE

A thesis submitted for the degree of

Doctor of Philosophy
In
Mechanical Engineering

Submitted by
Anil Kumar

Supervisor Co-Supervisor Co-Supervisor

Prof. V K Sethi Prof. Suresh Kumar Prof. Sachin Tiwari
Soni

Faculty of Engineering and Technology

RAM KRISHNA DHARMARTH FOUNDATION
UNIVERSITY, BHOPAL
2020
 CHAPTER-5 CONCLUSIONS
AND FUTURE SCOPE
Chapter-5 Conclusions and Future Scope

5. GENERAL

Energy security, high efficiency with economy feasibility, sustainable development

with environmental protection are the globally primacy topics. In present era the

growth of population is very fast, resulting energy demand is also increasing

exponentially mainly due to their modern life style, etc. Therefore, renewable based

24×7 energy solutions have to be invented. Conventional renewable energy

generation systems have enormous issues i.e. uninterrupted supply, energy storage

with controlled GHGs emissions. Unlike conventional renewable approach, an

innovative passive hybrid approach is the coupling of energy storage system with

Concentrated Solar Power (CSP) system. By using solar energy, the hybrid system is

able to generate huge amount of energy. These systems are characterized by various

advantages i.e. appropriate efficiency, no emissions of GHGs with very low operation

and maintenance costs etc.

Two experimental set ups with objective to proficient exploitation solar energy and

store through solid storage systems to provide the power 24×7. A 1 MWe (3.5 MW

thermal) solar power plant with 16 hours thermal storage capacity and A 1 kWe high

energy density thermal energy storage for concentrated solar plant were experimented

and found satisfactory results as per Indian climatic conditions.

CONCLUSIONS FROM PERFORMANCE OF 1 MWe (3.5

MWh) SOLAR POWER PLANT WITH 16 HOURS THERMAL
STORAGE CAPACITY

The plant operates on Rankine cycle principle. The Parabolic Reflector concentrates

the solar radiation towards the in-house developed, highly efficient cavity receiver.

The cavity of the Receiver which is made of monolithic cast iron acts as perfect black

Ram Krishna Dharmarth Foundation University, Bhopal Page 93

Chapter-5 Conclusions and Future Scope

body and thus provides excellent thermal storage. The boiler grade coil around the

body acts as a heat exchanger which allows for water to exchange heat and convert

into steam.

The thermal storage can be operated between 250 oC to 550oC and can be discharged.

The steam generated is mostly super- heated steam and the rest is saturated steam to

pertaining pressure from 38 bar to 44 bar gauge pressure.

CONCLUSIONS FROM PERFORMANCE OF 1 kWe HIGH

ENERGY DENSITY THERMAL STORAGE

It was concluded from various readings that the temperature achieved at the tip of

solar focal point about 1400oC. The temperature at the core mid-point was found to be

of the order of 310oC which is sufficient to generate steam for heat transfer studies.

COMPARATIVE ANALYSIS OF SOLID THERMAL

STORAGE SYSTEM WITH OTHER SYSTEMS

S.N. Parameter India One Mount MNRE R&D Project ,

abu Bhopal
Technical Parameter
1 Thermal Capacity 3.5 MWth 40 KWth
2 Electrical Capacity 1 MWe 10 kWe
3 Heat source(CSP 60 sq m parabolic 16 sq m parabolic
System) Scheffler dish Scheffler dish
4 Storage medium Cast Iron Halide Salt
4.1 Specific heat(KJ/Kg K) 2100 3500
4.2 Life (year) 25 35
4.3 Heat redundancy ( min) 6000 8000
4.4 Density (kg/m3) 120 80
4.5 chemical composition
4.6 Chemically activeness inert inert
4.7 Impact on Environment
5 Area (Acre) 8 4.5

Ram Krishna Dharmarth Foundation University, Bhopal Page 94

Chapter-5 Conclusions and Future Scope

FUTURE SCOPE

The long term aim of this research work is to develop the necessary technology know-

how to enable the manufacturing process in India for large scale MW systems.

Promote energy efficient concept of steam generation through solar thermal storage

and apply in Carbon Capture Sequestration (CCS) system, shown as Fig. 5.1.

Fig. 5.1 Steam generation through solar thermal storage and apply in CCS system

Ram Krishna Dharmarth Foundation University, Bhopal Page 95