Tribhuvan University
Institute of Engineering
Pulchowk Campus
A Report on
Design of Solar PV Home System Design
Submitted by:
Himal Chaulagain
PUL075MSREE008
Submitted to:
Dr. Nawaraj Bhattarai
Department of Mechanical Engineering
Jan, 2020
Table of Contents
Table of Contents........................................................................................................................................ii
List of Figure................................................................................................................................................ii
List of Table.................................................................................................................................................iii
1. Background:.........................................................................................................................................1
2. Energy requirement Calculation:.........................................................................................................1
3. Battery Selection..................................................................................................................................2
4. Selection of Solar PV Module..............................................................................................................3
5. Selection of Charge Controller.............................................................................................................4
6. Selection of DC/AC Inverter.................................................................................................................5
7. Selection of Wire Size..........................................................................................................................5
8. Result:..................................................................................................................................................6
List of Figure
Figure 2: Technical Specification of Solar Tubular Battery........................................................................3
Figure 3 : Solar PV Specification................................................................................................................4
Figure 4 : Layout of Solar Home system.....................................................................................................5
List of Table
Table 1: Load Profile of SHS......................................................................................................................1
Table 2: Load Profile of SHS......................................................................................................................2
Table 3: Price Estimation............................................................................................................................6
Design of Solar Home System
1. Background:
Melamchi is a municipality in Sindhupalchok District in the Bagmati Zone of central Nepal. At
the time of the 1991 Nepal census it had a population of 3936 and had 710 houses in the village.
Government of Nepal has initiated a drinking water project called Melamchi water supply
project to Kathmandu Valley. The Melamchi Valley is typically narrow, steep Himalayan River-
Valley. The lower valley slopes are very steep, rocky and "V" shaped in the High Mountain
whereas in the Middle the valley slopes are dissected by rolling alluvial tars at the bottom. The
middle mountain slopes, have gentler aspect and are the sites of settlements. The upper mountain
slopes are very steep, rocky and with pointed ridgeline. On the contrary, upper hill slopes of
middle part are also often rounded and smooth and are exploited for mountain agriculture and
settlement. Elevation differences between the valley floor and surrounding ridges exceed over
1,000 m in the upper part.
. The location of his house is (Google earth coordinate)
Location : Bhotechour, Sindhupalchok
Latitude : 27° 47' 29.4288'' N
Longitude : 85° 29' 59.5068'' E
I have carried out the load survey for this house, and following are the load details:
Table 1: Load Profile of SHS
S.N Description Wattage Quantity Daily Remarks
(watt) operation
Hours
1 LED Light Bulb 7 7 4
2 Ceiling Fan 50 2 1
3 Television 50 1 5
4 Mobile Charger 5 1 1
The solar insolation and temperature of the area is measured for a week and the average solar
irradiance is 777.27 W/m2 and the average temperature ranges from 15 ° C to 29 ° C over a year.
2. Energy requirement Calculation:
Energy consumption for each lamp is calculated by multiplying the power rating (Watt) of it by
the time of operation hour
Table 2: Load Profile of SHS
S.N Particular Quantity Power Total Daily Watt Hour
. (Watt) Watt Operation
( Hour)
1 Light Bulb 7 7 49 4 196
2 Ceiling Fan 2 50 100 1 100
3 Television 1 50 50 5 250
4 Mobile Charger 1 5 5 1 5
Total 204 551
3. Battery Selection
Based on the load of the system, the system voltage shall be 12 Volt DC.
Days of Autonomy shall be 2 days.
Battery Efficiency: 80 %
Depth of Discharge: 80 % (DOD)
Capacity of Battery = Total Watt Hour x Autonomy Days / ( Battery voltage x Efficiency
x DOD)
= 551 x 2 /( 12 x 0.8 x 0.8 ) = 143.49 Ahr, 12 Volt
Figure 1: Technical Specification of Solar Tubular Battery
1 no’s of 150 Ah, Solar Tubular Battery, 3DC2355/3 made by Volta Industries limited shall
be used.
4. Selection of Solar PV Module
Peak sun for the above mentioned place is assumed to be 4.5 hour
The size of the Solar PV Module depends upon the current to be generated by the solar module
which is given by the formula:
De-rating factor =0.9
Columbic efficiency = 0.95
Im = E / ( Hp x Bv x Derating fact. X Columbic eff.) ; where E is the required energy
Hp: Peak Hour
Bv: Battery Voltage
Im: Current generated by solar module (Amp = 14.32 Amp
That means required wattage of panel = 14.32 * 12 = 195.6 Watt
Figure 2 : Solar PV Specification
150 watt , Astropower Pannel, corresponding current at maximum temperature is 8.8, hence two
numbers of such panel in Parallel can supply the current at a cell temperature of 25 ⁰ C.
However the panel should supply the given load at maximum average temperature ie, 18 ⁰ C.
At 18 ⁰ C, the Panel temperature will be: T air + (0.031*Irradiance in W/m2)= 18
+(0.031*777.27)= 42.09 ⁰ C.
At 42.09 ⁰ C, the panel output will be = 300 *(1-0.0045*(42.09-25))) = 276.92 Watt; which can
supply the given load.
Hence, 2 nos of 150 Watt, in parallel , Astropower Pannel is selected
5. Selection of Charge Controller
Charge controller should be capable to withstand short circuit current ( I sc) of module and
maximum battery load current.
Since the panel are connected in parallel short circuit current shall be twice the short circuit
current of single panel.
Isc = 2 x 9.8 = 19.6 Amp
Maximum load current = Total Load / Battery Voltage = 204 /12 = 17 Amp
Hence, the maximum value 19.6 Amp shall be selected CXNup 20, , current rating of 20 Amp,
has been selected.
6. Selection of DC/AC Inverter
The power rating of the inverter is given by formula
Pinverter = Pload / (PF x Efficiency) , where Pload Load power, PF = Load Power Factor, shall be taken
as 0.8, Efficieny = 0.85
Hence; Plnverter = 204 / ( 0.8 * 0.85) = 300 VA
By, considering the surge factor, JYP-300-1 12V dc/230V AC, of Rating 300 VA
Selection of Switch
5 Amp switch can be used for all lights, and 5 Amp power socket with switch has been selected
for the Charging port and Television.
7. Selection of Wire Size
Switch ‘D’ wire
Lamp
‘E’ wire
Solar Charge
module controller TV
‘A’ wire ‘C’ wire Inverter ‘F’ wire
Charging
‘B’ wire Socket
+-
Figure 3 : Layout of Solar Home system
The size of the wire required is calculated by using the Standard Wire Gauge (SWG) formula as
following.
0.3× L × I M
S=
ΔV
where,
S = Cross Sectional Area of wire (mm2)
L = Length of wire joining solar module and charge controller (meter)
IM = current flowing from solar module to charge controller (Ampere)
V = maximum allowed voltage drop percentage (5%)
Wire A
The distance between the solar PV and charge controller is about 7 m, for L = 7 m, IM= 9.8 A
and V= 3% then using equation, we get
S = 6.86 mm square
Wire B
Allowable voltage drop = 1 %
The maximum load current is 17 A or less and distance between the charge controller and battery
is 2.5 m then required wire size is S= 12.75 Sq. mm
Wire C
Same as wire B
Wire C, D & E :
Since, the voltage level is 230 volt; the lowest size AC wire, 3/22 copper cable is selected.
8. Result:
12 volt solar PV system with 1 nos. of 150 Amp hour battery in Parallel, 2 nos. of 150 watt
Solar PV module in Parallel, 300 VA, 12 V/ 230 V AC inverter has been selected.
Table 3: Price Estimation
Total Remarks
S.N Particular Specification Quantity Unit Unit Rate Amount
Solar Tubular Rate are
Battery, VOLTA 150 Amhr, provided by
1 3DC2355/3 2 No Lotus Energy
12 V
Pvt.Ltd.
22826 45652 Kathmandu
Solar Panel 150 watt 150 Watt, 12
2 2 No
ASTROPOWER V
7950.00 15900
3 Inverter, JYP-300-1 300 VA, 12 V 1 No
6441 6441
Charge Controller,
4 20 Amp 1 No
CXNup 20 3000 3000
Light Bulb Set with
5 7 Watt 7 No
Switch Holder 450 3150
Charger Power
6 No
Socket 5 Amp 3 250.00 750
7 DC Copper Wire 8 mm. sq. 14 mtr
150 2100
8 DC Copper Wire 16 mm. sq. 5 mtr 210 1050
9 AC Wire 220 mtr
3/22 18 3960
Solar PV Module
support structure,
10 hot dipped 1 Lot
galvanized metal
frame complete set 1800 1800
Lightning and
11 1 Lot
Earthing System 3,500.00 3,500.00
Installation and Rate is Taken
12 Transportation 1 Lot from Jilla Dar
System 1000 1000 Rate
Total Amount 88153
