The purpose of this experiment was to determine how different temperatures affected the voltage (mV), the current (mA), and the power (watt) generation of a solar cell.  I became interested in this idea when I had to change my topic; this current topic is equally, if not harder than the initial topic.  The information gained from this experiment will help those using solar power to determine when to charge their backup batteries at the most efficient time.
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 My hypothesis is that the higher the temperature, the lower the voltage (mV), and the current (mA) generation.  I also hypothesize that the power (wattage) will be higher at lower temperatures during this experiment.  I base my hypothesis on information I procured from Solar Solutions (e-mail) stating that lower temperatures have little effect on solar cell generation, however higher temperatures do.
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 The constants in this study were:

 The same light source (100 watts)
 The same light position (45.72 cm above the cell)
 The same solar cell position
 The same solar cell (Radio Shack 2cmX4cm)
 The same voltmeter
 The same temperatures (43, 41, 32.5, 25, 10, 7, 4, 1.5 All centigrade)
 The same methods/tools used

The manipulated variable was the temperature of the solar cell surroundings.  The responding variable was the generation of current (mA), voltage (mV), and the power (wattage).  To measure the responding variable I will, at each temperature measure the level of current (mA), and voltage (mV) for each temperature for four separate tests.  Then I will multiply the current (mA), and voltage (mV) readings for each test to get the power (wattage).
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 The materials used in this experiment were:

Quantity   Description

1 Solar cell (Radio Shack 2cm by 4cm)
1 Digital Voltmeter
1 Digital indoor/outdoor thermometer
1 Lamp w/100 watt bulb
1 Shoe box
2 Dowels- 2.5 cm
2    Large bottle of airbrush propellant
1 Hairdryer
1 Pair of scissors
N/A    Packing tape- lots of it
1    Large piece of plywood
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The procedures to reproduce my experiment are as follows:

1. Gather all the materials. (you may want to lacquer the plywood to make the tape stick better)
2. Take the plywood, and glue the dowels apart about the width of the solar cell.
3. Cut a hole larger (2 cm) than the cell itself on top of the box, and cover with a piece of clear, hard plastic.
4. Run the external sensor of the thermometer onto the dowels.
5. Glue the bottom side of the solar cell on top of the dowels.
6. Attach the probes of the voltmeter onto the solar cell.
7. Place the shoe box over the cell so that you can see the cell through the hole.
8. Tape all sides (and the wires).  Leave one side alone.
9. Cut a “door” so that you can put the hair dryer in there to warm it up.
10. Place the lamp to my specifications shown in experiment design, and centered over the cell.
11. To test the cell, simply take the millivolt and milliamp readings for each temperature.
12. Repeat step #11 as needed (I did four times.)
13. Multiply the millivolt and milliamp readings together to get the wattage.
14. Finalize data.
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Introduction to Solar Energy

Solar Energy is radiant energy produced in the sun as a result of nuclear fusion reactions.  It is transmitted to the earth in portions of energy called photons, which interact with the earth's atmosphere and surface.  Solar energy is collected naturally in the earth's atmosphere, plant life, and the oceans.  This collection causes winds, and when wind is directed through a wind generator produces electricity.  This also helps produce hydroelectric energy.

Direct collection

Artificial devices, called solar collectors, are used to directly collect solar energy.  There are two fundamental types: flat plate collectors and concentrating collectors.  Flat plate collectors intercept solar radiation on an absorber plate equipped with a carrier fluid.  The temperature of the carrier fluid (liquid or air) increases as it passes through flow channels in the collector.  Flat plate collectors are capable of heating carrier fluids up to 82° C (180° F) and are used efficiently for water and comfort heating.  Typical hot water and comfort heating systems also include circulating pumps, temperature sensors, automatic controllers, and a storage device.

For air conditioning, central power generation, and industrial heat requirements, the temperature of the carrier fluid is boosted by conventional heating methods.  Complex concentrating collectors are devices that optically reflect and focus solar energy onto a small receiving area.  This concentration magnifies the solar energy so that temperatures are raised to several hundred or even several thousand degrees Celsius.  Solar furnaces use concentrators to produce temperatures as high as 4000° C (7200° F).  Such furnaces are ideal for research requiring high temperatures and contaminant free environments.
 In the central receiver, or “power tower,” concept, an array of reflectors reflects and focuses the sun's rays onto a water boiler that produces steam. The steam can be used in a conventional power plant cycle to produce electricity. Solar cooling can be achieved by using solar energy as a heat source in an absorption cooling cycle.  Photovoltaic electricity is produced when solar cells made from semiconductor materials directly convert solar radiation into electricity.

How temperature affects the production of a solar cell

 Unfortunately, there is not much information that I could reach on this subject, however I did find some info from a company called Solar Solutions.  An employee, Sonia Vogl E-mailed me and said simply that cold doesn't affect a cell, but warmth does.
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 The original purpose of this experiment was to determine how different temperatures affected the voltage (mV), the current (mA), and the power (watt) generation of a solar cell. The results were that the voltage went down at higher temperatures, the current went up at higher temperatures, and the wattage was higher at lower temperatures.
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 My hypothesis is that the higher the temperature, the lower the voltage (mV), and the current (mA) generation.  I also hypothesize that the power (wattage) will be higher at lower temperatures during this experiment. The results of the experiment indicate that my hypothesis should be accepted and rejected.  Because of the results of this experiment, I wonder if the size and quality of the cell makes a difference
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Sonia Vogl, re:solar energy science project, [Online] Available Email: sonia@essex1.com, December 13, 1998

Solar Energy, Microsoft Bookshelf, 1998

Solar Energy, Microsoft Encarta, 1996

Photovoltaic Cells, Microsoft Encarta, 1996

Photovoltaic Index, [Online] Available http://www.canrom.com, December 12, 1998

Solar Power, The Volume Library, 1997

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