- Active solar heating employs the use of solar cells to collect and absorb solar radiation. The solar cells convert the radiation to heat and transfer it to the interior of the building. There are two ways active solar heating works. The first way is through solar liquid heating. Solar liquid heating warms water or antifreeze through the use of solar cells. The liquid is then pumped into the home and heats it via radiators. In some instances, this method is also used to heat pools. The second method of active solar heating is solar air heating. Solar panels are used to warm air, which warms the home through a forced air pump. Active solar heating systems are often designed to meet 40 to 80 percent of a home's heating needs, as less than 40 percent is not cost effective and more than 80 percent usually requires the use of too many solar cells.
- Passive solar heating is the use of the sun to naturally warm a building. Homes heated through passive solar heating have large windows facing south. They are well insulated and often have overhangs over the windows to keep the home cool when sun is at its highest. Passive solar homes also take advantage of insulated curtains and windows to minimize heat loss.
- A solar electric system uses photovoltaic cells to absorb solar radiation. These photovoltaic cells are semiconductors. When the cells absorb sunlight, electrons are knocked loose in what is called the photoelectric effect. The free electrons travel to a circuit where they form an electrical current. Cells are usually connected to form panels, each panel creating 10 to 300 watts. A home or a building will usually have several panels for its power supply. The panels can be fixed at a specific angle or they can be on a tracking device to maximize power for a day. Solar electric systems can be stand alone or can be hooked up to the power grid. There are several solar array systems in the southwest that supply the electric grid.
