PDF《Home Made Energy》

s look at a little bit of the science and other details behind solar energy before we go any further. In order to make electricity from the energy released by the sun, panels designed to collect such energy are required. These solar panels work on the basis of some integrated photovoltaic cells meant to C as the name itself suggests C turn the light ( photo ) into electricity ( voltaic ). You will often see this word abbreviated to PV. Solar cells represent the basic unit responsible for creating energy within a solar- power generating system. Although materials used to make solar panels differ, silicon is the most common. Silicon solar cells are semiconductors in solid state and able to generate direct current if stimulated by photons. These silicon solar cells can be divided into four types: single-crystal (or monocrystalline) cells, polycrystalline cells (sometimes known as multicrystalline or thick-film cells), amorphous cells (also referred to as thin-film or vapor-deposition cells) and, finally, hybrids of the monocrystalline and amorphous technologies). They all have their place but single-crystal cells, with the exception of more expensive hybrids, are the most efficient when it comes to producing energy. The other two types have their own kind of efficiency but they do not match the productivity of single-crystal cells. The semi-conductors, of which these cells are made, comprise the crucial active ingredient which make solar panels work. A chemical reaction is triggered when the sun'

s rays hit the surface of these semi-conductors which sets electrons free from their atoms thus generating electricity. It'

s important to note that even cloudy days will excite some electricity from your PV cells, though a lot less than a cloudless one. Progress continues in optimizing solar panels (such as with the hybrid technologies mentioned above) to extend their capacity to collect an increasing amount of energy;

with research and development, solar power may well come to represent an increasingly reliable source of ener........