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Set536: Photovoltaic Technology Question Paper
Set536: Photovoltaic Technology
Course:Bachelor Of Science In Engineering
Institution: Kenyatta University question papers
Exam Year:2009
KENYATTA UNIVERSITY
UNIVERSITY EXAMINATIONS 2008/2009
FIFTH YEAR EXAMINATIONS FOR THE DEGREE OF BACHELOR OF
SCIENCE IN ENERGY ENGINEERING
SET 536 PHOTOVOLTAIC TECHNOLOGY
DATE: Monday 1st December 2009 TIME:
11.00am-1.00pm
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Instructions
1. This paper contains five questions
2. Attempt any three questions
3. All questions carry equal marks
4. State assumptions made and define all symbols used
Q1.
a)
What are the basic components of a photovoltaic system and describe their
functions as used in solar homes
[4 marks]
b)
A photovoltaic module with 108 cells is connected in series and an area of
1.281 sq-m has the following measured characteristics at the following
reference conditions: Short circuit current is 8.7 Amps, open circuit
voltage is 60 volts, maximum power is produced when current is 8 Amps
and 48 Volts. Other data include temperature coefficient of the
short circuit are 1.325 x 10-3A/K and -0.0775 V/K, respectively.
i)
Determine the values of Saturation and load current;
[8 marks]
ii)
Determine the series resistance and maximum power generated
[8 marks]
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Q2. You have been assigned a job to design a photovoltaic power generating system
for use at Kenyatta University student hostel accommodating 100 students all year
round. Describe how you would go about carrying out this exercise.
a)
Designing and recommending the size of the PV system needed
(8 marks)
b)
A photovoltaic module with 72 cells is connected in series
and an area of 0.854 sq-m has the following measured
characteristics at the following reference conditions: Short
circuit current is 8.7 Amps, open circuit voltage is 60 volts,
maximum power is produced when current is 8 Amps and 48
Volts. Other data include temperature coefficient of the short
circuit are 1.325 x 10-3A/K and -0.0775 V/K, respectively.
Determine the maximum power point efficiency at a cell
temperature of 67.2oC
(12 marks)
Q3. A small household lighting system is powered by from 8V storage battery having
a 30 Ah supply when fully charged. The lighting is used for 4hours each night at
3 Amps. As an energy engineering graduate from Kenyatta University, you are
asked to design a suitable photovoltaic system that will charge the battery from an
arrangement of silicon cells.
a)
How will you arrange the cells?
(8 marks)
b)
How will the circuit connected? (6 marks)
c)
How will you test the circuit performance? (6 marks)
Q4. a)
Using illustrations, describe in detail basic principles of a photovoltaic cell
(5 marks)
b)
What is the annual payment of and yearly interest of charged if Kshs
110,000 solar photovoltaic installation is to be financed by a 10% down
payment with a balance borrowed at an annual interest rate of 9% for 20
years. The payments are to be made at the end of the year. The market
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discount rate is 8%. What is the present worth of series of interest
payments
(15 marks)
Q5.
a)
Discuss various methods are used for storing power generated
from a solar photovoltaic module and the principle governing the
process
(4 marks)
b)
Define the efficiency of a solar cell. Under what conditions is it
normally measured
(2 marks)
c)
A farmer in a rural countryside wants to use solar energy lighting
his homestead and powering domestic appliances. The following
are his requirements:
3 bedroomed house, sitting room, corridor, kitchen, bathroom,
toilet and two security lights. The appliances include 1 black and
white television set rated at 35W, DC and one radio rated 5W, DC.
Use the following information: solar panel is rated 60W, DC,
current output = 3 A, Average sunshine hours = 6 hours, battery
size = 100Ah, lights are 10W, overall system efficiency = 70%. All
lights are used for one hour each. TV and radio are used for 3
hours. Describe how you would go about sizing his system. Use
illustrations where possible.
(14 marks)
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