PV system designing
(Class exercise 20th March 2023)
Design a photovoltaic system for a home situated in Islamabad with one day of autonomy. Currently residents are
using grid electricity to fulfill its energy requirements. Electricity rate can be assumed as 31 Rs/kWh. Load is used in
the same manner (100%) throughout year at each month (base case).
Homeowner wants to obtain between 70% to 80% or above of the power from PV and rest from the grid electricity.
Following load and PV specifications are available.
The daily load of the home is:
i.
ii.
iii.
iv.
5 LED lights and each light is of 20 watts being used for 10 hours (total 100 Watts)
Two fans and each fan are of 100 watts being used for 7 hours (Total 200 Watts)
One TV of 120 watts being used for 4 hours
(120 Watts)
And one laptop using 100 watts used for 6 hours
(100 Watts)
All are AC loads and used 7 days per week
PV System
PV can be used mono Sci from “Jinko Solar (mono-Si - JKM615N-78HL4-V 615W)” for RETSCREEN data base.
PV systems is fixed and clamped and facing true south.
Cost of the system



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Price of the PV is Rs 150 / Watt of PV
Price of Battery is @Rs 10/Wh
Price of the inverter is Rs 30/Watt
O&M cost is 2% of PV cost
Transportation cost is Rs 5000/- Spare parts cost is 5% of the PV cost and Training & commissioning cost is
5% of the PV cost.
And at the end of the Project life the whole system can be disposed off @ of 20% of the PV cost.
Charge controller efficiency can be assumed 90%
Find out
IRR, NPV, Equity payback period and net cash flows
Consider these three cases when intermittent resource-load correlation is
i.
Zero
ii.
Negative And
iii.
Positive
Perform calculation for each case separately.
PV life can be assumed 25 years, Inflation rate is 18%, while the fuel escalation rate is assumed to be 20 %.
1. Draw a chart between PV capacity (kW) (from 1.0 to 4.0 kW) and corresponding electricity
delivered to the above-mentioned load for zero, Positive and negative correlations with three hours
of autonomy, six hours of autonomy and zero hours of autonomy.