Title: Design and Performance Assessment of Various Concentrating Solar Collectors

CHAPTER ONE

Background of the Study

This section presents the context and rationale of the proposed research. It introduces the
main areas of study, their related theories, trends, the research problem, scope,
delimitation, and its significance.

Introduction

Solar energy represents a renewable energy source that has experienced significant
growth in popularity in recent years, emerging as a cleaner and more sustainable option
compared to conventional fossil fuels. Technological advancements have enhanced the
efficiency, affordability, and accessibility of solar energy, making it available to a global
audience (Saurenergy & Shah, 2023). The solar energy sector is undoubtedly a prime candidate
for meeting future energy demands, as it excels in availability, cost efficiency, accessibility,
capacity, and overall effectiveness when compared to alternative renewable energy sources
(Kannan & Vakeesan, 2016). Solar Energy is classified into either Photovoltaic (PV) Solar
Energy, Solar Thermal Energy (STE), Concentrated Solar Power (CSP), Passive Solar Energy,
or Building-Integrated Photovoltaics (BIPV). Each type has various technologies employed in its
system ensuring to capture and utilize the energy from the sun either for water heating, steam,
or electricity generation. The dramatic drop in solar PV costs has accelerated global adoption.
From $76.67 per watt in 1977 to $0.36 per watt in 2014, the decreasing costs are making solar
energy one of the most competitive renewable energy sources. In 2013, solar photovoltaic (PV)
technology had the highest annual growth rate among renewable energy sources at 39%
(Kannan & Vakeesan, 2016). In addition, there is an increasing interest in hybrid solar systems,
where PV is combined with other renewables like wind or diesel backup systems, to provide
more reliable energy, especially in areas with inconsistent solar conditions. Meanwhile,
Concentrating Solar Power (CSP) systems, while not as widely deployed as PV, are gaining
traction. CSP technology often operates at higher efficiencies than PV and can store heat for
later use, helping to meet energy demand during non-sunlight hours. CSP is gaining attention
because of its thermal energy storage capability, allowing energy to be stored and used during
non-sunlight hours, addressing one of the primary weaknesses of PV systems (Kannan &
Vakeesan, 2016).
 According to Ismail et al., (2015), the Philippines has potential for solar energy
applications both on grid and off-grid. It specifies that the average solar insolation in the country
varies from 1643 to 2008 kWh/m2 per year. Furthermore, based on Global Solar Atlas, an
online tool developed by the International Renewable Energy Agency (IRENA) that provides
free access to high-quality solar resource maps and data globally, it shows that Global
Horizontal Irradiation, Direct Normal Irradiation, Diffuse Horizontal Irradiation, and other solar
map data of Legazpi, Albay, Philippines implies that locality is conducive utilizing solar energy.

Moreover, this suggests that the country's geographical condition and solar irradiation are
conducive to harnessing Solar Energy. However, most of the systems in the country currently
utilize only PV Solar Energy. As reviewed by Pandey et al., (2022), entitled “Solar energy
utilization techniques, policies, potentials, progresses, challenges and recommendations in
ASEAN countries”, it indicates that the average installation of PV modules in the Philippines
amounts to providing 1048 MW in 2020. Furthermore, the annual reports and renewable energy
strategies published by the Philippine Department of Energy (DOE) which provides a
comprehensive overview of the nation's energy composition reveal that the recent findings
suggest that solar photovoltaic (PV) technology is rapidly emerging as one of the leading
renewable energy sources having 30% annual growth rate in the Philippines, driven by declining
costs and the country's rich solar resource potential. In contrast, other types of solar energy
technologies are yet to be developed and invested in the country. One of which is Solar
Concentrated Power (CSP).

Concentrated solar power (CSP) represents a technology for electricity generation that
harnesses thermal energy derived from solar radiation focused onto a limited surface area. This
process involves the use of mirrors to direct sunlight towards a receiver, where the heat is
absorbed by a thermal energy transfer medium (primary circuit). The collected heat can then be
utilized directly, as in the case of water or steam, or through a secondary circuit to drive a
turbine and produce electricity (Zhang et al., 2013). Currently, there are four distinct CSP
technologies available: parabolic trough collector (PTC), solar power tower (SPT), linear Fresnel
reflector (LFR), and parabolic dish systems (PDS). These Concentrated Solar Power (CSP)
technologies are functioning at medium to large scales, predominantly situated in Spain and the
United States. In addition, the Parabolic Trough Collector (PTC) technology stands out as the
most developed CSP design, closely followed by Solar Tower Technology (Zhang et al., 2013).
On top of that, Levosada et al., (2022) stipulate that there are currently no CSP plants in the
Philippines. Accordingly, their mapping unveiled that there are suitable sites in the Philippines
for CSP plants which include: Ilocos Sur, Pampanga, Mindoro, Masbate, and Maguindanao.
These areas have a total area of 27.9 km2 and a projected total power output of 733 MW.
These details show the potential of including and developing CSP technology and plants as a
prominent renewable energy source for our energy crisis. Another study by Galvan, J.P. (2021)
entitled “Suitability Analysis for Solar Energy System Development using GIS and AHP in
Cagayan Province, Philippines”, aimed to identify an appropriate location for the development of
solar energy systems and to assess potential energy generation in Cagayan province,
Philippines. The research utilized and showcased the integration of geographic information
systems (GIS) with multi-criteria decision-making (MCDM) methodologies, specifically
employing the analytical hierarchy process (AHP). Additionally, in the study, “Technical
Feasibility of a Concentrated Solar Power Plant in the Philippines: A Case Study in Tacurong
City, Sultan Kudarat” by Aguirre, Jr. et al., (2024) investigates the potential for implementing
Concentrated Solar Power (CSP) in Tacurong City, Sultan Kudarat. Utilizing the System Advisor
Model (SAM), a range of CSP scenarios were evaluated based on the local weather data of
Tacurong. An analysis was performed on the calculated levelized cost of electricity (LCOE) and
capacity factor across all scenarios. The findings indicated that CSP systems equipped with an
auxiliary heater achieved significantly higher capacity factor values, whereas configurations
lacking an auxiliary heater necessitated a larger solar multiple, resulting in increased LCOE.
Such trends in CSP studies done in the Philippines imply that only a few contributions to the
CSP body of knowledge have been mostly limited to assessing, mapping, and suitability of
locations in the country. Meanwhile, there is not yet research done in designing and assessing
the performance of various concentrating solar collectors used for CSP in the country.

This study aims to address the gap by designing and assessing the performance of various
types of concentrating solar collectors, specifically Parabolic Trough Collectors (PTC),
Compound Parabolic Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar Dish
Concentrators (SDC). The research will evaluate the efficiency, cost-effectiveness, and overall
viability of these technologies in Legazpi, Albay, providing valuable insights for future solar
energy projects in the region. This endeavor will also contribute to the country’s considerably
scarce body of knowledge related to Concentrated Solar Power (CSP), particularly to various
concentrating solar collectors used in such solar energy. By analyzing the performance of these
concentrating solar collectors in a tropical setting, this study seeks to contribute to the
development of renewable energy solutions in the Philippines and guide policymakers,
engineers, and investors in selecting the most appropriate CSP technology for local
applications.

Statement Of The Problem

This study aims to address this gap by designing and assessing the performance of
various types of concentrating solar collectors, specifically Parabolic Trough Collectors (PTC),
Compound Parabolic Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar Dish
Concentrators (SDC).

Specifically, the research questions to be answered are:

1. What design and configurations are needed to optimize the performance of Parabolic
Trough Collectors (PTC), Compound Parabolic Concentrators (CPC), Linear Fresnel
Reflectors (LFR), and Solar Dish Concentrators (SDC) in terms of:

(a) Reflector Shape and Geometry

(b) Thermal Receiver Design

(c) Heat Transfer Fluid and Flow Rate

(d) System Efficiency and Performance Monitoring

2. What are the optimal fabrication and materials for constructing these collectors in a
tropical climate?

3. What experiments and performance metrics will be used to assess the efficiency of
each solar collector?

4. How acceptable are these solar technologies to users and stakeholders in terms of
cost, environmental impact, and technical viability?

Objectives of the Study

 The Philippines, despite its abundant solar energy potential, lacks comprehensive
research on the designing and assessing the performance of various concentrating solar
collectors under its unique climatic and geographical conditions. Concentrating Solar Power
(CSP) technologies, which are effective in harnessing solar energy for applications such as
power generation and steam production, have been widely studied and implemented in other
countries. However, there remains a significant gap in understanding how these technologies
perform in the Philippine context, which experience a tropical climate with high solar irradiance
and intermittent cloud cover. The study is designed to address the issues mentioned earlier by
focusing on these specific objectives:

1. To design and provide the configuration needed to optimize the performance of

Parabolic Trough Collectors (PTC), Compound Parabolic Concentrators (CPC), Linear
Fresnel Reflectors (LFR), and Solar Dish Concentrators (SDC) in terms of:

(a) Reflector Shape and Geometry

(b) Thermal Receiver Design

(c) Heat Transfer Fluid and Flow Rate

(d) System Efficiency and Performance Monitoring

2. To determine the optimal fabrication and materials for constructing these collectors in
a tropical climate.

3. To determine experiments and performance metrics that will be used to assess the
efficiency of each solar collector

4. To determine the acceptability of these solar technologies to users and stakeholders

in terms of cost, environmental impact, and technical viability.

Assumptions of the Study

The researcher will assume the following:

● The various concentrating solar collectors (Parabolic Trough Collectors,

Compound Parabolic Concentrators, Linear Fresnel Reflectors, and Solar Dish
Concentrators) are technically feasible and capable of operating efficiently in the
tropical climate of Legazpi, Albay, Philippines.
● The solar irradiance and weather patterns in Legazpi are suitable and consistent
enough to test the collectors effectively, even accounting for intermittent cloud
cover, which may affect energy capture.
● The materials available for constructing the collectors are assumed to be suitable
for maintaining efficiency and durability in tropical conditions, such as high
humidity and heat.
● Successful CSP technology implementation will contribute to a reduction in
conventional energy usage in the country.
● The cost-effectiveness, environmental benefits, and technical reliability of these
solar technologies will encourage positive reception from stakeholders and
potential users in the Philippines.
 Table 1. Statement and Hypothesis of the Problem
Statement of the Problem Hypothesis of the Study
What design and configurations are Design modifications in reflector shape,
needed to optimize the performance of thermal receiver configuration, and
Parabolic Trough Collectors (PTC), heat transfer fluid will significantly
Compound Parabolic Concentrators enhance the thermal efficiency and
(CPC), Linear Fresnel Reflectors energy output of PTC, CPC, LFR, and
(LFR), and Solar Dish Concentrators SDC under tropical climate conditions
(SDC)? in the country.
What are the optimal fabrication and Collectors constructed with corrosion-
materials for constructing these resistant, thermally efficient materials
collectors in a tropical climate? will demonstrate higher durability and
efficiency compared to standard
materials under tropical climate
conditions in the country.
What experiments and performance Performance metrics and heat loss
metrics will be used to assess the rates will be sufficient to accurately
Scope
efficiency of each solar collector? assess the efficiency of each collector and
type under the experimental conditions
in Legazpi, Albay.
How acceptable are these solar The selected solar collector designs will
technologies to users and stakeholders be well-received by stakeholders if they
in terms of cost, environmental impact, demonstrate cost-effectiveness,
and technical viability? minimal environmental impact, and
reliable performance, leading to a high
acceptability rate among potential
users in the region.

Delimitation

The study Design and Performance Assessment of Various Concentrating Solar

Collectors will be conducted at Brgy. 25, Lapu-Lapu St., Legazpi City. The various
Concentrating Solar Collectors will be designed on materials suitable to its operating conditions,
with respect to its availability, and will be assessed by a single system. The collectors will only
be Parabolic Trough Collectors (PTC), Compound Parabolic Concentrators (CPC), Linear
Fresnel Reflectors (LFR), and Solar Dish Concentrators (SDC). The assessing system will use a
flexible setup to adapt to the various collectors and lessen costs.

Significance of the Study

The study will be beneficial to persons, groups of persons, and especially the following:

DEPARTMENT OF ENERGY. This study will help provide data on the existing body of
knowledge on CSP technologies and influence decisions on utilizing Concentrating Solar Power
as a renewable energy in solving the energy supply problem in the Philippines.

ENVIRONMENT. This study will benefit the environment by reusing heat energy for energy
production that does not utilize fossil fuels that emits greenhouse gasses, which lessens the
effects of global warming.

SOCIETY. This study will serve the society through establishing a locality-based framework for
the use of CSP technologies in solar energy that may address energy issues in urban areas.

ENGINEERS. This research provided a significant advance in the development of concentrating

solar collector prototypes.

STUDENTS. This study could benefit students by giving insights into the technologies relating to
CSP.

TEACHERS. This study could help teachers for they could relay their knowledge about
mechanical solutions and applications in addressing real-life problems.

FUTURE RESEARCHERS. This study would be beneficial to future researchers because this
will serve as part of their starting point as they innovate devices related to CSP systems and as
well as creating new ideas.
 CHAPTER TWO

REVIEW OF RELATED LITERATURE

This chapter presents the related literature and studies the researcher reviewed to fortify

the gravity of the study. This will also provide an in-depth inquiry to thoroughly comprehend the

study.

Related Literature

Solar energy, derived from the Sun’s radiation, holds immense potential to generate

heat, facilitate chemical reactions, and produce electricity. The amount of solar energy that

reaches the Earth is vastly greater than the world’s current and future energy requirements. If

properly harnessed, this abundant and widely dispersed source could satisfy all future energy

needs. In the 21st century, solar energy has gained significant attention as a renewable energy

source due to its inexhaustible supply and non-polluting nature, distinguishing it from finite fossil

fuels such as coal, petroleum, and natural gas, which are associated with environmental

degradation and pollution (Britannica, n.d.).

Thermal energy refers to the energy produced by a substance whose molecules and

atoms vibrate more rapidly due to an increase in temperature. The molecules and atoms that

make up matter are constantly in motion. When a substance is heated, the rise in temperature

causes these particles to move faster and collide with each other more frequently. The thermal
energy of a substance is directly proportional to the temperature; the hotter the substance, the

more its particles move, and the higher its thermal energy (Solar Schools, n.d.).

Solar thermal energy is a highly promising renewable energy resource that converts

solar radiation into heat, which can either be directly used for various applications or

transformed into electricity. This technology includes solar space heating, solar water heating,

Concentrated Solar Power (CSP), and other applications. Among these, solar water heating and

CSP are the most rapidly growing. The core of these technologies are collectors, which gather

heat from solar radiation and can operate in a broad temperature range. CSP, in particular, has

seen significant growth, with over 4800 MW of projects in operation by 2015, and is projected to

meet over 5% of the world’s electricity demand by 2040 (Asif, 2017).

Concentrating Solar Power (CSP) is a renewable energy technology recognized for its

capability to convert solar radiation into thermal energy, which can be stored and used to

generate electricity, ensuring a reliable energy source even during non-sunlight hours. CSP

systems utilize mirrors or lenses to concentrate sunlight onto a receiver, where the energy is

converted into heat and subsequently powers steam turbines or other power generation

systems. This technology is particularly effective in large-scale applications, with systems like

parabolic troughs and solar power towers playing a crucial role in capturing solar energy

efficiently. CSP is integral to modern renewable energy infrastructures because it provides

consistent and sustainable electricity generation (ScienceDirect, n.d.).

Concentrated Solar Power (CSP) systems operate by using mirrors or lenses to focus

sunlight onto a receiver, where the solar energy is collected and converted into heat. This heat

is transferred to a working fluid, which is then used to drive a turbine and generate electricity.

According to SolarPACES, this process exemplifies the fundamental principles behind CSP

technologies, including Parabolic Trough Collectors (PTC) as well as other collector systems

such as Solar Power Towers and Linear Fresnel Reflectors. These systems are crucial for
efficiently harnessing solar energy and are highly relevant to research focused on optimizing

CSP technologies in various contexts.

Accurate flow and temperature measurement are critical components in the effective

operation of Concentrated Solar Power (CSP) systems. According to KROHNE, precise

monitoring of heat transfer fluids is essential for optimizing thermal efficiency, as it ensures

proper heat capture, storage, and delivery to power generation systems. This is particularly

relevant to CSP technologies such as Parabolic Trough Collectors (PTC), Solar Power Towers,

and Linear Fresnel Reflectors, where maintaining optimal thermal conditions directly impacts

system performance. The importance of accurate measurement tools aligns with this study's

objective of assessing and designing various CSP technologies, as these tools are vital for

evaluating performance and maximizing operational efficiency.

Solar thermal concentrating power (CSP) plants play a vital role in renewable energy

generation by effectively capturing and storing solar energy, as highlighted by the Schaeffler

website. CSP technologies, such as parabolic troughs and solar towers, are designed to

harness solar radiation and store it for use during non-sunny hours, providing a reliable and

continuous energy supply. This aligns closely with your study, which evaluates various CSP

technologies in the context of the Philippines. Research on CSP's ability to generate and store

energy is particularly relevant for optimizing renewable energy solutions in tropical climates,

where high solar irradiance can be leveraged to address energy demands sustainably.

In this article, Mohamad (2024) emphasizes the critical role of thermal receiver design in

optimizing the efficiency of Concentrated Solar Power (CSP) systems, focusing on key

parameters such as receiver geometry, material properties, and heat transfer mechanisms. The

study highlights how advanced receiver geometries, including cavity and tubular designs,

improve heat absorption and reduce radiative and convective losses. Material selection, such as

the use of nickel-based alloys and ceramics, is shown to enhance thermal conductivity and

resist high-temperature stress, ensuring durability under intense solar irradiance. Additionally,
the research explores the importance of efficient heat transfer mechanisms, using coatings that

maximize solar absorptance and minimize thermal emittance, as well as optimizing fluid flow for

effective thermal energy transport. This work provides valuable insights for adapting CSP

technologies to regions with high solar irradiance, like the Philippines, where optimizing receiver

design is essential for improved system performance.

Concentrating collectors or reflectors are systems designed to reflect or refract solar

radiation from a large reflective surface (aperture) to a smaller absorber or receiver. The optical

concentration is defined by the ratio of the radiation intensities on the reflective aperture (G r)

and the absorber (Ga), represented as Co = Gr/Ga. The geometric concentration is given by the

ratio of the areas of the absorber (A r) and aperture (Aa), expressed as Cc = Ar/Aa, where the

aperture area is much larger than the absorber area. Various types of concentrating collectors

are employed in solar applications, particularly for processes such as desalination. The primary

types of concentrating collectors include Parabolic Trough Collectors (PTC), Compound

Parabolic Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar Dish Concentrators

(SDC), each providing a unique method for concentrating solar energy to enhance system

efficiency and performance (Belessiotis, Kalogirou, & Delyannis, 2016).

A Parabolic Trough Collector (PTC) is one of the most developed solar thermal energy

technologies. It consists of a parabolic-shaped mirror made of polished metal, which focuses

solar irradiance onto an absorber tube located at the focal point of the mirror. The absorber tube

contains a heat-absorbing fluid, typically a molten salt mixture or synthetic oil, which is heated

by the focused sunlight. The system is mounted on a solar tracker to ensure continuous

alignment with the sun. Heat exchangers are used to transfer the thermal energy from the

molten salt to a working fluid, converting it into steam. This steam then drives a turbine to

generate power. Parabolic troughs are widely used in solar thermal power plants due to their

ability to efficiently convert solar energy into electricity (Kamran, 2022).

 Linear Fresnel Reflectors (LFR) are two-dimensional concentrating solar systems that

operate similarly to parabolic troughs but use single-axis mirrors for solar tracking. The solar

receiver is positioned along the focal line of the mirrors, with concentration ratios ranging from

30 to 80, and operating temperatures around 500°C. LFR systems are composed of an array of

flat mirrors, resembling a Fresnel lens, that focus sunlight onto a receiver located on a tower.

LFR can be considered a modified version of the parabolic trough, designed to enhance

efficiency and reduce capital costs. The thermal efficiency of LFR systems typically ranges from

8% to 12%, and they have a plant capacity ranging from 30 to 700 MW, depending on the

application (Kumar, Prakash, & Dube, 2017).

A Compound Parabolic Concentrator (CPC) is a reflective, non-imaging optical device

designed to maximize the concentration of light energy through the use of specially configured

parabolic properties. CPCs are constructed with a rotated parabolic shape, where the wide end

collects divergent light, which is then reflected and concentrated at the narrow output end. The

design of CPCs is characterized by an "acceptance angle," which defines the angular range in

which the concentrator can effectively collect light. This type of concentrator is widely used in

solar applications due to its ability to gather and focus sunlight efficiently without requiring

precise alignment with the light source (Optiforms, 2023).

Solar Dish Concentrators (SDC) are highly efficient, point-focus solar thermal collectors

that use a parabolic dish to focus sunlight onto a receiver located at the focal point of the dish.

The dish collects and concentrates solar energy, which is then converted into thermal energy

through a receiver that typically contains a heat transfer fluid or a Stirling engine. The

concentrated solar energy can be used for power generation or other thermal applications.

SDCs are known for their high concentration ratios, which enable them to achieve high

temperatures, making them suitable for small-scale power generation systems. These

concentrators are advantageous due to their ability to generate electricity at high efficiencies,
even in locations with low solar insolation. Additionally, their design allows them to track the sun

with great precision, ensuring optimal energy capture throughout the day (Zhang et al., 2013).

The article from Solaric discusses the efficiency and suitability of different types of solar

panels—monocrystalline, polycrystalline, and thin-film—commonly used in industrial

applications. While the focus is on photovoltaic (PV) technology, the article’s insights into the

evolving adoption of solar systems are highly relevant to Concentrated Solar Power (CSP)

studies. Just as PV systems benefit from advancements in material selection and optimization,

CSP technologies, such as parabolic troughs and solar power towers, could also see similar

improvements. These advancements are especially pertinent to the Philippines' increasing shift

toward renewable energy solutions, where CSP can play a key role in meeting growing energy

demands sustainably.

Thermal receiver design is integral to the performance of solar concentrators, with

factors such as material properties, geometric configurations, surface coatings, and heat

transfer mechanisms significantly impacting efficiency. Materials like nickel-based alloys and

ceramics are favored for their high thermal conductivity and resistance to thermal stresses.

Geometric designs such as cavity and tubular receivers enhance heat absorption and reduce

radiative and convective losses, while selective surface coatings, such as cermet layers,

optimize solar radiation absorption by maintaining low emissivity at high temperatures. Efficient

heat transfer mechanisms are characterized by parameters like the heat transfer coefficient and

Nusselt number, N u=hL/ K which represent the efficiency of convective heat exchange

between the receiver and working fluid (Mohamad, 2024).

The efficiency of solar concentrators is highly dependent on the selection of heat transfer

fluids (HTFs) and the optimization of their flow rates, which influence thermal conductivity, heat

transfer coefficient, and overall system performance. Common HTFs such as molten salts and

synthetic oils are preferred due to their high specific heat capacity and stability at elevated

temperatures, enabling efficient heat storage and transfer. Flow rate optimization is critical for
maintaining efficient convective heat transfer while minimizing pressure drops and energy

losses. The performance of the flow regime can be characterized by the Reynolds number,

ℜ= pVD ensuring sufficient turbulence to enhance heat exchange efficiency (Rajendran et al.,

2020).

Thermal energy storage (TES) involves the storage of heat or "cold" in a storage

medium, which can either be a naturally occurring structure (e.g., the ground) or an artificially

made container designed to minimize heat loss or gain from the surroundings (e.g., water

tanks). TES systems typically consist of a storage medium along with equipment to inject and

extract heat to and from the medium. There are three main types of TES modes: sensible heat

storage, latent heat storage, and thermochemical storage. Historically, heat storage has been

primarily in the form of sensible heat, where the temperature of the medium is raised to store

energy. This form of energy storage plays a critical role in various applications, including

Concentrated Solar Power (CSP) systems, where it enables the storage of thermal energy for

later use in electricity generation (Koohi-Fayegh & Rosen, 2019).

Related Studies

In the study by Pérez and Soria (2018), the evolution of concentrated solar power (CSP)

technology is discussed, highlighting the efficiency improvements and technological

advancements that have shaped its development. This is directly relevant to the current study,

which seeks to evaluate and optimize different CSP collector technologies in a tropical climate.

Understanding the historical progress and challenges in CSP systems can help inform the

design and assessment of these technologies, particularly in the Philippines, where CSP

adoption is still emerging.

Daneshazarian et al. (2018) conducted an extensive review of concentrating

photovoltaic thermal (CPVT) systems, focusing on their design, thermodynamic performance,

and practical applications. CPVT collectors, which integrate photovoltaic and thermal
technologies, were found to significantly outperform standalone PV or thermal systems in both

thermal and electrical efficiency, achieving global efficiencies exceeding 65.1%. Key design

elements, such as concentration ratio, working fluids, and cooling mechanisms, were analyzed,

highlighting the trade-offs between efficiency and cost. The study emphasized the role of

advanced materials and innovative concentrator designs, including Fresnel lenses and parabolic

trough collectors, in optimizing energy output for domestic and industrial applications. It

concluded that CPVT systems hold strong potential as a competitive renewable energy

technology, especially when efficiency, compactness, and environmental impact are considered.

This review serves as a foundational resource for assessing and improving the design and

performance of concentrating solar collectors

Zhang et al. (2016) provide a comprehensive review of concentrating solar power (CSP)

systems, focusing on the performance, efficiency, and optimization of various CSP

technologies. This is particularly relevant for the current study, as the research highlights key

factors such as thermal performance and system configuration, which are essential in designing

CSP systems suitable for the Philippine context. The study’s findings on system efficiency and

operational challenges can inform the development and evaluation of CSP collectors in tropical

climates, addressing both technical and environmental considerations.

Luo et al. (2016) provide a detailed analysis of optimizing CSP systems, focusing on

heat transfer fluid selection, advanced receiver designs, and efficient system configurations.

They emphasize the use of high-performance HTFs, selective surface coatings for thermal

receivers, and innovative reflector arrangements to enhance energy absorption and minimize

losses. The study is particularly relevant to tropical climates like the Philippines, addressing

challenges such as high humidity and intermittent cloud cover while highlighting cost-efficiency

and durability considerations.

In this study (Chukwuka, 2013), the Concentrated Solar Power (CSP) technology offers

substantial potential for producing clean, renewable energy on a large scale by converting solar
radiation into heat and electricity. Key components such as heliostats, advanced thermal energy

storage systems, and power conversion units enable efficient energy generation and

dispatchability, even during periods without sunlight. Despite challenges like relatively low

efficiency, ongoing innovations such as optimizing thermodynamic cycles, enhancing heat

transfer mechanisms, and integrating advanced materials aim to improve system performance

and reduce costs. Economic viability is often assessed using tools like the System Advisor

Model (SAM), which highlight CSP's feasibility in regions with abundant solar resources.

Furthermore, CSP's capability to provide grid-scale, reliable energy solutions with thermal

energy storage distinguishes it as a pivotal technology in transitioning toward sustainable and

low-carbon energy infrastructures capable of meeting growing global energy demands.

The article by Luo et al. (2016) discusses the performance and optimization of solar

thermal power systems, with a focus on the effectiveness of different collector technologies.

This relates to the study by providing insights into the key components that enhance the

efficiency of CSP systems, such as heat transfer fluids, receiver designs, and the integration of

energy storage. These findings are crucial in evaluating and optimizing CSP technologies,

especially for areas like the Philippines where solar resource potential is high.

Koohi-Fayegh and Rosen (2019) delve into various energy storage methods, with a

focus on the critical role of thermal energy storage (TES) in improving the operational reliability

of Concentrated Solar Power (CSP) systems. They explore sensible heat storage, which uses

materials like water, molten salts, or rocks to store energy by raising their temperature, and

latent heat storage, which employs phase-change materials for efficient energy absorption and

release during transitions between states. The study highlights TES as a key enabler for CSP

systems to deliver continuous energy during cloudy periods or nighttime, addressing one of the

primary limitations of solar energy. Their analysis emphasizes that integrating TES into CSP

designs not only enhances energy reliability but also improves grid stability, making CSP

systems more viable and competitive in global renewable energy markets.

 The article by Lu et al. (2012) provides a comprehensive analysis of the economic and

performance factors of Concentrating Solar Power (CSP) systems, specifically addressing the

trade-offs between different CSP technologies. The study highlights that the performance and

cost-effectiveness of CSP systems depend heavily on the selection of the appropriate

technology, taking into account geographical location, solar radiation, and local climate

conditions. This research aligns with efforts to optimize CSP systems in tropical regions like the

Philippines, where solar insolation is high and consistent.

Lu et al. (2012) analyze the economic and performance aspects of various CSP

technologies, emphasizing the importance of optimizing system configurations based on

geographical and climatic conditions. They highlight the critical balance between high upfront

capital investment and the long-term benefits of increased energy output and efficiency, noting

that proper site-specific adjustments, such as selecting appropriate reflector types and

integrating thermal storage, significantly influence cost-effectiveness. This study underscores

that in developing countries like the Philippines, tailoring CSP designs to local conditions is key

to achieving economic viability and encouraging widespread adoption.

The economic viability of Concentrated Solar Power (CSP) technologies is closely tied to

the geographical location and solar irradiance levels, as well as technological configurations that

optimize efficiency. In regions with high solar radiation, CSP presents a promising solution for

sustainable energy production, although the cost-effectiveness of the technology varies

depending on site-specific factors (Joubert & Arndt, 2012). This insight is highly relevant for the

Philippines, where similar environmental conditions may help optimize CSP performance, as it

has considerable solar potential for such energy systems.

Synthesis of the State of the Art

This research study highlights the potential of Concentrated Solar Power (CSP)

technologies as a sustainable energy solution, particularly in regions with high solar irradiance.
Globally, CSP systems like Parabolic Trough Collectors (PTC), Compound Parabolic

Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar Dish Concentrators (SDC)

have demonstrated exceptional efficiency and reliability, with extensive deployment in countries

such as Spain and the United States. These systems are not only capable of converting solar

energy into electricity with high thermal efficiency but also excel in storing energy for use during

non-sunny periods, addressing a critical limitation of photovoltaic (PV) systems. Despite these

advancements, the Philippines, with its abundant solar resources, has yet to fully embrace CSP

technologies. Research in the country has predominantly focused on mapping suitable sites and

theoretical feasibility studies, identifying regions like Ilocos Sur, Mindoro, and Sultan Kudarat as

ideal for CSP deployment. However, the practical design, fabrication, and performance

evaluation of CSP collectors remain largely unexplored in the local context.

The Philippine energy landscape is dominated by PV systems, which, while effective,

lack the capacity for energy storage and often face efficiency challenges due to intermittent

cloud cover. CSP, with its superior thermal energy storage capabilities and high capacity

factors, presents a promising alternative. Studies have shown that CSP systems tailored with

auxiliary heaters and optimal solar multiples can significantly enhance energy reliability and

efficiency, particularly in tropical climates like that of the Philippines. Yet, there is a noticeable

gap in research on the adaptation of CSP designs—such as reflector geometries, thermal

receiver configurations, and heat transfer fluids—to suit local environmental conditions

characterized by high humidity, heat, and occasional heavy rains.

This project aims to bridge this gap by developing and accessing various CSP

technologies specifically optimized for the Philippines’ tropical setting. It seeks to evaluate the

efficiency, cost-effectiveness, and material durability of CSP systems while exploring their

environmental impact and acceptability among stakeholders. By addressing these critical

aspects, the study not only contributes to the global body of knowledge on CSP technologies

but also provides localized data and recommendations to guide policymakers, engineers, and
investors in harnessing the country’s solar potential. Through innovative design and

performance assessment, this research aspires to position CSP as a viable, sustainable, and

scalable solution to the Philippines' energy challenges, fostering a shift toward a more

diversified and resilient renewable energy infrastructure.

Gap Bridged by the Studies

The Philippines has abundant solar energy potential, yet the country's focus on solar

energy technologies has largely been limited to photovoltaic (PV) systems, with minimal

development or utilization of Concentrating Solar Power (CSP) technologies. While CSP

systems have proven effective globally, particularly in countries like the United States and

Spain, there is a noticeable lack of research and infrastructure tailored to the Philippine context.

This gap is exacerbated by the absence of studies assessing the design and performance of

various concentrating solar collectors under the unique climatic conditions of the Philippines,

characterized by high solar irradiance, tropical temperatures, and intermittent cloud cover.

Moreover, existing literature and research on CSP technologies in the Philippines

primarily focus on location mapping and suitability analysis, without delving into the practical

design, construction, or performance evaluation of CSP collectors. There is limited exploration

of cost-effective, efficient, and durable designs for Parabolic Trough Collectors (PTC),

Compound Parabolic Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar Dish

Concentrators (SDC) that could cater to the specific needs of the region.

Addressing this gap, this study aims to design and assess the performance of various

concentrating solar collectors to provide localized data on their efficiency, cost-effectiveness,

and technical viability in Legazpi, Albay. By developing innovative designs and evaluating their

performance in a tropical climate, the research will bridge the disconnect between global

advancements in CSP technology and the lack of practical application in the Philippines.
Furthermore, this study will contribute to the limited knowledge on CSP systems, offering

insights for policymakers, engineers, and educators to promote renewable energy education

and adoption in the country.

Theoretical Framework

The study aims to evaluate the efficiency, cost-effectiveness, and overall viability of

different types of concentrating solar collectors (Parabolic Trough Collectors (PTC), Compound

Parabolic Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar Dish Concentrators

(SDC)) in the Philippine context. The study seeks to provide a detailed analysis of how these

CSP technologies perform in tropical climates, focusing on optimizing system design, material

selection, and overall performance. The theoretical framework supporting this research draws

upon several interconnected theories, including the Theory of Solar Energy Conversion, Heat

Transfer Theory, Sustainability Theory, Environmental Adaptation Theory, and Technology

Adoption Models.

The Theory of Solar Energy Conversion provides the foundation for understanding how

solar radiation is transformed into usable thermal energy. In Concentrated Solar Power (CSP)

systems, sunlight is concentrated using mirrors or lenses to focus on a thermal receiver, where

heat is generated and used either directly or for electricity production. This theory is

fundamental to understanding the principles of each type of concentrating solar collector

employed in the study. For each collector type (PTC, CPC, LFR, SDC), this theory will guide the

design and optimization of the reflector shape, the configuration of the thermal receiver, and the

overall efficiency of energy conversion. This framework ensures the study focuses on the

scientific mechanisms of solar concentration, absorption, and heat transfer that are essential for

optimizing CSP performance.

Heat Transfer Theory

 The Heat Transfer Theory plays a critical role in the operation of CSP systems.

Understanding the mechanisms of heat transfer — including conduction, convection, and

radiation — is essential for designing efficient thermal receivers and optimizing the performance

of the CSP collectors. This theory guides the evaluation of the heat transfer fluid (HTF) and its

flow rate, both of which are critical to the performance of CSP systems. In particular,

understanding how thermal energy is transferred from concentrated solar radiation to the HTF,

and from the HTF to the storage or power generation system, will inform design decisions for

materials, fluid selection, and system configurations. Given the tropical climate of the

Philippines, where high solar insolation and fluctuating weather conditions are prevalent, the

application of this theory will help ensure that heat transfer processes are efficient and effective

under local conditions.

Sustainability Theory underscores the importance of utilizing renewable energy

technologies to promote long-term environmental, social, and economic well-being. In the

context of the Philippines, which faces challenges related to energy security and environmental

sustainability, CSP technologies represent a promising solution to meet future energy demands.

This theory supports the need for transitioning from fossil fuels to clean energy sources like

solar power, helping to reduce greenhouse gas emissions and mitigating the effects of climate

change. The study will assess the sustainability of CSP technologies, including their potential to

reduce carbon footprints, enhance energy independence, and support the Philippines’ goals of

achieving a more sustainable energy mix.

Environmental Adaptation Theory focuses on how local environmental conditions must

be considered when designing and implementing technologies. In the Philippines, the tropical

climate — with high solar insolation, frequent rainfall, and occasional typhoons — presents

unique challenges for solar energy systems. CSP systems must be adapted to these

environmental factors to optimize their efficiency and ensure durability. This theory informs the
design and selection of materials that can withstand the region’s humidity, precipitation, and

temperature fluctuations. Additionally, it guides the consideration of site-specific factors such as

solar irradiation levels, local weather patterns, and land use when evaluating potential CSP

system locations in the Philippines.

The Technology Acceptance Model (TAM) and the Diffusion of Innovations Theory

provide insights into how new technologies are adopted and integrated within a given

community or country. The Technology Acceptance Model (TAM), developed by Davis (1989),

helps assess the perceived usefulness and ease of use of the CSP systems, focusing on the

perspectives of engineers, policymakers, and potential users in the Philippines. TAM will help

gauge the likelihood of CSP technologies being adopted based on their perceived technical

viability, cost-effectiveness, and potential for improving energy access.

The Diffusion of Innovations Theory (Rogers, 2003) provides further understanding of

how innovations, like CSP technologies, are disseminated and accepted across regions. Key

factors such as relative advantage, compatibility with local needs, and observability will

influence the rate at which CSP systems are adopted in the Philippines. By assessing the

adoption barriers and facilitators, the study will offer insights into strategies for encouraging the

widespread integration of CSP technologies in the country.

The Energy System Theory emphasizes the complex interactions within energy systems,

where various technologies (including CSP) must be integrated to create a balanced and

reliable energy grid. For the Philippines, where energy demand is increasing and supply

reliability is an ongoing challenge, CSP systems could provide an important supplement to other

renewable energy sources, such as photovoltaics (PV) and wind energy. This theory supports

the idea of hybrid systems, where CSP works in combination with other renewable energy

sources to increase the overall reliability, efficiency, and storage capacity of the energy system.
By integrating CSP into the broader energy infrastructure, the Philippines can better address

energy supply challenges, especially in off-grid and remote areas.

 Figure 1. Theoretical Paradigm

Conceptual Framework

This conceptual framework focuses on the design, testing, and evaluation of various

Concentrated Solar Power (CSP) technologies in the Philippines, specifically in the region of

Legazpi, Albay. The primary CSP systems under consideration are Parabolic Trough Collectors

(PTC), Compound Parabolic Concentrators (CPC), Linear Fresnel Reflectors (LFR), and Solar

Dish Concentrators (SDC). These systems will be assessed based on key design parameters

such as reflector shape, thermal receiver design, heat transfer fluid, and system efficiency.

Furthermore, the study will take into account the local climatic and geographical conditions,

which are crucial for tailoring the systems to operate efficiently in a tropical environment with

high solar irradiance and occasional cloud cover.

The design process for each CSP system will involve selecting optimal configurations,

materials, and components to ensure that each system is tailored to local conditions.

Construction and setup will follow, where prototypes of each CSP technology will be built and

tested in real-world settings in Legazpi. These systems will be equipped with the necessary

components, including thermal receivers and heat transfer fluids, to effectively collect and store

solar energy. Data will be collected through field testing to measure the performance of each

system under actual environmental conditions, focusing on energy output, heat retention, and

overall efficiency.

The output of this study will include a detailed evaluation of each CSP system's performance,

including insights into their efficiency, energy generation potential, and scalability. Based on the

results, design recommendations will be made to optimize the performance of each system,

improving their ability to meet local energy needs. The study will also provide a feasibility report
on the adoption of CSP technology in the Philippines, assessing factors such as cost-

effectiveness, environmental impact, and technical viability for large-scale implementation.

A key feature of the conceptual framework is the inclusion of a feedback loop. After testing and

analyzing the performance of each CSP system, feedback from users, stakeholders, and

policymakers will be collected to assess the practical viability and acceptability of the systems.

This feedback will be used to refine the designs and configurations of the systems, ensuring that

they are optimized for local use. The iterative process of testing, feedback, and refinement will

help ensure that the systems are continually improved, providing valuable insights for the

development of renewable energy solutions in the Philippines.

In summary, this conceptual framework outlines a systematic approach to designing and

assessing CSP technologies in the Philippines, with a focus on performance, efficiency, and

local adaptability. The feedback loop ensures that the systems are continuously improved based

on real-world data and stakeholder input, providing a comprehensive pathway to integrating

CSP technology into the country's renewable energy landscape. This framework aims to

address the knowledge gap in CSP research in the Philippines, contributing to the development

of sustainable energy solutions that can meet the country's future energy demands.
Figure 2. Conceptual Paradigm
 Endnotes

Ashok, S. (n.d.). Solar energy | Definition, Uses, Advantages, & Facts. Encyclopedia

Britannica. Retrieved November 23, 2024, from

https://www.britannica.com/science/solar-energy

Asif, M. (2017). Fundamentals and application of solar thermal Technologies. In Elsevier

eBooks (pp. 27–36). https://doi.org/10.1016/b978-0-12-409548-9.10093-4

Belessiotis, V., Kalogirou, S., & Delyannis, E. (2016). Indirect Solar Desalination (MSF,

MED, MVC, TVC). In Elsevier eBooks (pp. 283–326). https://doi.org/10.1016/b978-0-12-

809656-7.00006-4

Chukwuka, C., & Folly, K. A. (2013). Overview of Concentrated Solar Power. Journal of

Energy and Power Engineering, 7(12), 2291-2299.

D. Galvan, J. P. (2021). Suitability analysis for solar energy system development using

GIS and AHP in Cagayan Province, Philippines. Mindanao Journal of Science and

Technology, 19(2).

Ismail, A. M., Ramirez-Iniguez, R., Asif, M., Munir, A. B., & Muhammad-Sukki, F. (2015).

Progress of solar photovoltaic in ASEAN countries: A review. Renewable and

sustainable energy reviews, 48, 399-412.

Joubert, W., & Arndt, S. (2012). The economic viability of concentrated solar power

(CSP) in the current energy market. Energy Policy, 47, 86-92.

https://doi.org/10.1016/j.enpol.2012.04.020

Kamran, M. (2022). Energy sources and technologies. In Fundamentals of Smart Grid

System (pp. 23–69). https://doi.org/10.1016/b978-0-323-99560-3.00010-7

Kannan, N., & Vakeesan, D. (2016). Solar energy for future world: - A review.

Renewable and Sustainable Energy Reviews, 62, 1092–1105.

https://doi.org/10.1016/j.rser.2016.05.022
Koohi-Fayegh, S., & Rosen, M. A. (2019). A review of energy storage types,

applications, and recent developments. Journal of Energy Storage, 27, 101047.

KROHNE. (n.d.). Concentrated solar power (CSP). KROHNE. Retrieved November 23,

2024, from https://ph.krohne.com/en/industries/power-generation-industry/concentrated-

solar-power-csp-power-generation-industry

Kumar, A., Prakash, O., & Dube, A. (2017). A review on progress of concentrated solar

power in India. Renewable and Sustainable Energy Reviews, 79, 304–307.

https://doi.org/10.1016/j.rser.2017.05.086

Levosada, A. T. A., Ogena, R. P. T., Santos, J. R. V., & Danao, L. A. M. (2022). Mapping

of Suitable Sites for Concentrated Solar Power Plants in the Philippines Using

Geographic Information System and Analytic Hierarchy Process. Sustainability, 14(19),

12260.

Luo, Z., Liu, L., & Zhang, H. (2016). Performance optimization of concentrating solar

thermal power systems: A review. Renewable and Sustainable Energy Reviews, 63, 64-

83. https://doi.org/10.1016/j.rser.2016.05.016

Lu, L., Li, Y., & Shao, Z. (2012). Economic and performance analysis of concentrating

solar power (CSP) systems: A review. Renewable and Sustainable Energy Reviews,

16(8), 6115-6129. https://doi.org/10.1016/j.rser.2012.07.063

Mohamad, K. (2024). Exploring the influence of optical and thermal parameters on the

effectiveness of parabolic trough collector receiver units. Clean Energy, 8(4), 15–33. 4o

Pandey, A. K., Kalidasan, B., Reji Kumar, R., Rahman, S., Tyagi, V. V., Krismadinata, ...

& Tyagi, S. K. (2022). Solar energy utilization techniques, policies, potentials,

progresses, challenges and recommendations in ASEAN countries. Sustainability,

14(18), 11193.
Pérez, J. M., & Soria, A. (2018). Concentrated solar power technology and its evolution.

Renewable and Sustainable Energy Reviews, 82, 1061-1074.

https://doi.org/10.1016/j.rser.2017.09.079

Rajendran, D. R., Sundaram, E. G., Jawahar, P., Sivakumar, V., Mahian, O., & Bellos, E.

(2020). Review on influencing parameters in the performance of concentrated solar

power collector based on materials, heat transfer fluids and design. Journal of Thermal

Analysis and Calorimetry, 140, 33–51.

Saurenergy, & Shah, J. (2023, February 6). Exploring the 5 main types of solar energy:

PV, STE, CSP, Passive Solar, BIPV. Saur Energy International.

https://www.saurenergy.com/solar-energy-blog/exploring-the-5-main-types-of-solar-

energy-pv-ste-csp-passive-solar-bipv#:~:text=Highlights%20%3A,Building%2Dintegrated

%20Photovoltaics%20(BIPV)

ScienceDirect. (n.d.). Concentrated solar power. ScienceDirect. Retrieved November 23,

2024, from https://www.sciencedirect.com/topics/engineering/concentrated-solar-power

Schaeffler. (n.d.). Solar thermal concentrating power plants. Retrieved from

https://www.schaeffler.ph/en/products-and-solutions/industrial/industry_solutions/

wind_sector_cluster/solar/solar_thermal_concentrating_power_plants/

Solaric. (n.d.). Types of solar panels for industrial use. Retrieved from

https://solaric.com.ph/blog/types-of-solar-panels-for-industrial-use/

SolarPACES. (n.d.). How concentrated solar power works. SolarPACES. Retrieved

November 23, 2024, from https://www.solarpaces.org/worldwide-csp/how-concentrated-

solar-power-works/

Thermal energy - Knowledge Bank - solar schools. (n.d.).

https://solarschools.net/knowledge-bank/energy/types/thermal

Zhang, L., Zhao, Y., & Tian, Y. (2016). Review of concentrating solar power systems and

components. Solar Energy, 133, 8-19. https://doi.org/10.1016/j.solener.2016.03.012

Zhang, H. L., Baeyens, J., Degrève, J., & Cacères, G. (2013). Concentrated solar power plants:

Review and design methodology. Renewable and sustainable energy reviews, 22, 466-

481.

Optiforms. (2023, October 18). Compound Parabolic Concentrator Design Guide.

Optiforms, Inc. https://www.optiforms.com/compound-parabolic-concentrator-

essentials/#:~:text=A%20Compound%20Parabolic%20Concentrator%20(CPC,using

%20a%20rotated%20parabolic%20shape.

Zhang, H. L., Baeyens, J., Degrève, J., & Cacères, G. (2013). Concentrated solar power

plants: Review and design methodology. Renewable and Sustainable Energy Reviews,

22, 466-481. https://doi.org/10.1016/j.rser.2013.01.009

Daneshazarian, R., Cuce, E., Cuce, P. M., & Sher, F. (2018). Concentrating photovoltaic

thermal (CPVT) collectors and systems: Theory, performance assessment, and

applications. Renewable and Sustainable Energy Reviews, 81, 473–492. DOI:

10.1016/j.rser.2017.08.013