Solar Electricity 101

Cloud9 Paradigm offers free online instruction on solar energy.

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Photovoltaic class syllabus
Instructor: Andrew Whitedove

Permaculture, renewable energy’s connection to permaculture:
What are basic needs? What basic needs can photovoltaic cells help us satisfy? Sanitation, warmth, safety.

Review history of photovoltaic technology:
1839:Nineteen-year-old Edmund Becquerel, a French experimental physicist, discovered the photovoltaic effect while experimenting with an electrolytic cell made up of two metal electrodes. 1873: Willoughby Smith discovered the photoconductivity of selenium.1916:Millikan provided experimental proof of the photoelectric effect.1918:Polish scientist Czochralski developed a way to grow single-crystal silicon.1923:Albert Einstein received the Nobel Prize for his theories explaining the photoelectric effect.1954:Chapin, and Fuller reported their discovery of 4.5% efficient silicon solar cells; this was raised to 6% only a few months later (by a work team including Mort Prince). 1955:Hoffman Electronics’s Semiconductor Division announced a commercial PV product at 2% efficiency; priced at $25/cell and at 14 mW each, the cost of energy was $1500/W.1957:Hoffman Electronics achieved 8% efficient cells. “Solar Energy Converting Apparatus,” patent #2,780,765, was issued to Chapin, Fuller, and Pearson, AT&T.1958:Hoffman Electronics achieved 9% efficient PV cells. Vanguard I, the first PV-powered satellite, was launched in cooperation with the U.S. Signal Corp. The satellite power system operated for 8 years. 1959:Hoffman Electronics achieved 10% efficient, commercially available PV cells.1960:Hoffman Electronics achieved 14% efficient PV cells.

What is the magic? Basic description of photovoltaic effect, basic dc electric theory, define volts, amps, resistance, watts.

What’s inside the box? single cell or polycrystalline ingot, ingot to wafers, wafers to cells, cells to modules.

How much electricity can we expect from sunlight? Review global insolation table and calculate output for student’s locations.

First step of the design process is to determine the need. Describe basic system types and diagram on whiteboard:

Utility grid tied or stand alone?
Grid tie. No emergency power, simple.
Stand alone: Charge control, inverter, batteries, back-up power, transfer switch.

Photovoltaic module experiment:
Determine module output using: volts = amps X resistance, watt = volts X amps, watts = work.

Wire sizing exercises

2 thoughts on “Solar Electricity 101

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