Solar Lab
Theory & Introduction –
Solar power and renewable energy sources are becoming a viable alternative to more traditional
forms of power generation. To learn more about the methods of generation and the current state
of the industry, four assignments are given on the Solar Lab Page. Please be sure to do each
assignment promptly. The Solar Lab should not take much time each week, but at the end of the
semester, we hope you have a good understanding of Solar Power and the uses of renewable
energy sources.
Goals for the Solar Lab –
1. An understanding of how solar power is generated
2. An understanding of the solar and wind system installed at Texas A&M
3. An understanding of how solar power can be integrated into private homes
4. An understanding of the issues of converting raw solar power into useable power
5. An understanding of emerging technologies in the solar industry
Theory –
The theory for this lab is given as links to articles and pages on the web. These links can be
found within the assignments on the Solar Lab Webpage. You are encouraged to find other
sources on the web or in the library that enhance your understanding of the material.
Prelab Assignments –
There are two prelab assignments with the Solar Lab that are due throughout the semester, and
they begin on the next page. These assignments should not be difficult. If you use the links and
the information on the solar web page, no assignments should take no more than a half an hour
or so. Contact your TA if you have any questions.
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Assignment 1 Due with Prelab 2
Use the Websites below, and any other sources you find, to understand the
following topics –
Renewable Energy
Solar Power
Solar Cells
Solar Systems
Suggested Websites –
http://www.eere.energy.gov/RE/solar.html
http://www.jxj.com/magsandj/rew/2001_02/staying_in_charge.html
http://www.astropower.com/ (Hint: Search on this site for how solar systems and solar cells
work)
http://www.howstuffworks.com/ (Hint: Search on this site for solar, solar cells and solar
systems.)
http://www.windows.ucar.edu/spaceweather/solar_cell_explain.html
Articles to find on IEEE Xplore (see instructions below):
1. “Green Power: What Is it and Where Can We Find It?” by Saifur Rahman in IEEE
Power & Energy Magazine, January/February 2003.
2. “Don’t Let the Sun Go Down on PV,” by Mohamad Shahidehpower and Fred
Schwartz in IEEE Power & Energy Magazine, May/June 2004.
To use IEEE Xplore:
1. Log on to one of the EE computers.
2. Go to http://ieeexplore.ieee.org/search/advsearch.jsp and search for the papers above.
3. Download the PDF file.
Work to Turn in:
1. Explain in your own words how solar panels take light and turn it into electric energy.
Include a description of the role of an inverter in solar systems. (at least a paragraph)
2. Identify 3 types of renewable energy and an example of its use. (at least a paragraph)
3. There are other uses for solar energy than photovoltaics. Go to the website:
www.eere.energy.gov/solar.
From the first page, explore the Solar Energy Technologies Program. Write a summary
of what you learn at this site. What work is being done to use solar energy for something
other than photovoltaic collection? Be sure to include something about the Hybrid Solar
Lighting (HSL) being developed at Oak Ridge National Laboratory. (at least 2
paragraphs)
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Assignment 2 Due with Prelab 9
Analysis of the Installation –
In order to determine which solar panels will work best for you, you should be able to calculate
the size, shape and cost of your system. Currently, we have 32 KC60 Photovoltaic Modules
installed on the roof of Zachry. The full specification sheet for these modules can be found at:
http://www.kyocerasolar.com/pdf/specsheets/kc60.pdf
When you are answering the following questions, be sure to show your work. Include a link to
any specification sheet and where you found the prices you used in your calculations.
Q1 – Calculate the total Watts expected from the solar array on the roof. (You may use the
maximum power rating for this calculation.)
Q2 – Calculate the Watts/meters2 expected for this installation.
Q3 – Calculate the Watts/kg expected for this installation.
Search the web for where you could buy 32 of these photovoltaic modules. (Suggestion: Use
Google.)
Q4 – Calculate the cost per Watt ($/W), cost per meters2 ($/W) and cost per kg ($/kg) for the
installation on the roof if you were to reproduce it.
You need to calculate the equivalent resistance of the wiring used to connect the solar panels in
the system. This will be an approximation, but it is a good place to start. In order to make these
calculations, please print out SolarRooftop.pdf. A link to this document can be found on the
Solar Lab Webpage. You will need to mark the path you calculate on this schematic. Please
hand this in so your TA can check the way you did your calculations. Note: On the diagram, the
path is shown in a very light blue. However, the 9th Chase is the one marked xx. It is the 11th
chase that runs to the 1st floor. It would be helpful to view the webpage on WebCT that
explains how the solar system was built.
On the roof, the wire first runs over to the edge and then across the roof to the 11th Chase from
the left top edge of the roof. The wire then runs to the 1st floor lab in 113D. (113D is accessed
from the 11th Chase from the left.) After the connection in 113D (approximate 15 feet to the DC
load and 15 feet back to the chase), the wire goes down to the ground floor. From the ground
floor, the wire runs over to the 8th Chase to connect to the inverter in 17CA. The information for
the Chases associated with room numbers is available on the building maps on each floor by the
elevators. There are 28 steps each 6 inches in height between any two floors. From there are 3
floors between 113D and the roof. There is 1 floor between the ground floor and the 1st Floor.
The wiring goes along the following path:
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Start at Solar Panels Æ To the top edge of the diagram Æ Across Roof to the 11th Chase Æ
Down to 1st Floor Æ In to lab stations in 113D (15 ft to a station, 15 ft back to the chase) Æ
Down to ground floor Æ Over to 17CA (8th Chase) Æ Back to the 11th Chase Æ Up to roof Æ
Back to solar panels
Note: If you do not show your calculations, you will get NO CREDIT!!! Please work
individually!
Q5 - Show all your calculations for the path of the wire. Hand in a copy of the roof layout with
your path marked. You will receive no credit for this assignment without the calculations and a
diagram of the path.
Q6 - The wire is 8 AWG Wire. If you go to: http://ohm.bu.edu/edf_info/info/wireresistance.html you will see data for this type of wire. Calculate the total resistance for the
wiring used from the solar panels.
Q7 - Obtain the equivalent circuit model for the solar panel with the variable load you have
been using throughout the semester.
Solar Lab
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Procedure –
Equipment to be used:
Chroma DC Load
Attachment to Solar Panels in the Lab.
PC Computer
Note: Before you begin your TA must enable the solar panels.
procedure without being sure your TA has enabled the solar panels.
Never perform this
Note: This procedure must be done 4 times throughout the semester. You should do it at
every lab meeting and at other times as indicated on the Lab Syllabus.
Before you begin taking data, record the Date, Time, Temperature of the Solar Panels,
Ambient Temperature on the roof, and a brief description of the weather outside. This
will help you when you are asked to make observations regarding the performance of
your solar panels.
2. Make sure the solar panel switch is in the “OFF” position before you turn on the load.
3. Start up (turn power “ON”) the dc programmable electronic load and wait until
initialization set up completed
1.
Fig. 1 Programmable electronic load
Change operation mode to constant resistor high “CRH” by pressing the “MODE” button
and then using the up or down arrows until “CRH” is shown up on the Main Frame LCD.
Press “ENTER.”
5. On the Main Frame LCD, change the resistor value to 1000Ω by using a digit key pad
and press “Enter” to confirm. Now, on the LCD, it displays “CRH1: 1000Ω.” Ignore
4.
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6.
7.
8.
9.
“CRH2.” If you end up on a different screen, just press enter until you are back to
“CRH1: 1000Ω.”
To test solar panel connected in series (48Vdc), turn the solar panel switch to “48Vdc”.
Now, the solar panel supplies power to the load (1000 Ω).
Be sure the load is connected. The red light over the load button under the output should
be illuminated.
Record the load terminal voltage and current shown on CH. 1 LCD in your Excel
Spreadheet. Also record the value of the load as shown on the display of the Chroma
Lad.
Press the UP arrow key so that “CHR1: 1000Ω” is flashing. Change load to various
values as given in the table.
• To change load resistance, press the up button and “CRH1: 1000Ω” shown on the
Main Frame LCD starts blinking
• Change the load resistance to 800 Ω using a digit key pad. You will see “CRH1:
800 Ω” appears on the LCD and then press “ENTER” to confirm
• If the resistance shown on the load is not the same as the resistance you entered,
enter the resistance the load is providing in the table.
10. When you have done your experiment for 48 Vdc and continue to the next experiment
(24 Vdc), you should
• Turn the solar panel switch to “OFF” position and then to “24 Vdc.”
• Repeat step no. 4-8
• Use a different page of the spreadsheet to save this data.
11. Turn the solar panel switch to “OFF” and then turn off the programmable load after you
have completed all experiments.
Suggestions:
There is an example Excel Spreadsheet available on the webpage. It is recommended you use
this to collect your data throughout the semester.
Lab Report Requirements –
The solar lab report is due at the same time Lab Report 9 is due.
1. Title page
2. Presentation of Data:
A. Data Tables – You do not have to show each data point. However, for each data
set collected, give the data, time, conditions and the maximum power for 24V, the
actual voltage, current, and load at that point and the maximum power for 48V,
the actual voltage, current, and load at that point. You could fill out a table
similar to the one below. Fill out a separate table for the 24V data and the 48V
data.
Date & Weather
Maximum
Voltage at Current
at Load
at
Time
Conditions
& Power
for that Point
that Point
that Point
Solar Intensity
data collected
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VI Curve - 48 Volt
4.500
4.000
3.500
Current
3.000
2.500
Series1
2.000
1.500
1.000
0.500
0.000
0.000
10.000
20.000
30.000
40.000
50.000
60.000
70.000
80.000
Voltage
Example PV Curve
200.000
180.000
160.000
140.000
Power
120.000
100.000
Series1
80.000
60.000
40.000
20.000
0.000
0.000
10.000
20.000
30.000
40.000
50.000
60.000
70.000
80.000
Voltage
B. Make a graph that has all of the Voltage versus Power curves. (Include lines for
all the 24V and 48V configurations.) Include comments on the conditions for the
largest power output.
C. Make a graph that has all of the Voltage versus Current curves. (Include lines for
all the 24V and 48V configurations.) Include comments on the conditions for the
curve that best meets the specifications given in the data sheet for the solar panels.
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3. Discussion – Answer the following questions:
A. What conditions produce the most power? Which configuration (24V or 48V)
produces the most power? Are these results what you would have expected?
B. Compare your graphs to the data sheet you used for the solar panels on the roof.
Does your data reflect the data given in the data sheets? Why or why not?
C. What is the maximum power (at a single point) produced by the solar panels?
Given the circuit model you drew in Solar Assignment 2, can you use the
maximum power to analyze your circuit model? Calculate if possible.
D. Which configuration should give you more power? Why? (Hint: Use Thevenin)
4. Conclusion – Write a conclusion summarizing what you have learned performing the
solar lab. Please include suggestions for improvements on the lab.
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Tables and Results –
It is strongly suggested that you download the example Excel Spreadsheet and use it throughout
the semester to record your data. If, for some reason, you do not wish to do this, you may use
the table given below each time you take data for the solar panels.
Date:______________________________Time on Lab Computer:____________am/pm
Weather Conditions:_______________________________________________________
Ambient Temperate on Roof:_________________Temperature of Solar Panels:________
Table 1 Experimental results
Load Requested
Actual
Load
Series (48 Vdc)
Voltage
(Volt)
Current
(Amp)
Parallel (24 Vdc)
Voltage
(Volt)
Current
(Amp)
1000 Ω
800 Ω
600 Ω
500 Ω
400 Ω
300 Ω
200 Ω
100 Ω
90 Ω
80 Ω
70 Ω
60 Ω
50 Ω
40 Ω
30 Ω
20 Ω
10 Ω
5Ω
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