Photovoltaic and passive solar design :: Essays Papers

Photovoltaic and passive solar design The sun is an infinite source of energy for our planet. In 1839 Edmund Becquerel, a French experimental physicist, discovered the photovoltaic effect while experimenting with an electrolytic cell made up of two metal electrodes. His Discovery was never taken to a commercial level until 1950 when silicon was used in semiconductors. In 1973 there was a oil crises in the U.S. and it created huge public awareness about the limited resource of fossil fuels, and led to the emerging market of solar photovoltaic technologies. This awareness was heightened even more by nuclear accidents like Three Mile Island in 1979. There are many different kinds of PV cells but all cells are made from silicon and have no moving parts. They convert light photons into moving electrons, which creates electricity. There are three major types of PV cells that have been developed in Germany, United Kingdom, and the United States. Using an experiment called integrated spectral response (ISR), it is possible to determine the efficiency of each cell. In a laboratory solar cells have proven to be up to 26% efficient. In the real world, however, the efficiency can vary. The light spectrum is what determines the solar cells to be used in a certain area. In order to decide which solar cell is best, the light used must be filtered by using IRS. The cell must also be hooked up to a spectrophotometer. A spectrophotometer measures the wavelength that is used by the solar cell. In an experiment done in Cairo, Egypt the procedure above was followed. The conclusion was that the monocrystalline cell from the United States was the most efficient cell. However, due to the price of this cell it would be better to use more polycrystalline cells made in Germany. Also determined by the experiment was the fact that humidity changes the efficiency of the cells. In a desert climate the US cell was the most effective. In the presence of moisture the German cell was the most efficient (Shaltout, etc). Photovoltaic cells are a great template for current solar panels. However, solar panels take 15 years to get back the energy it took to make them. This is not a very sustainable design. So it is not the only technology being developed.