Solar Hot Water
Solar hot water systems are relatively simple and low-cost systems designed to preheat water for standard gas, oil or electric hot water systems. A well designed solar hot water system provides 50-75% of a home's hot water needs, depending on the season. In addition, some state and federal clean energy tax incentives can reduce the cost of the installation. To qualify for tax incentives systems have to be certified by the Solar Rating and Certification Corporation (SRCC) with an OGC 300 rating; collectors must carry an OGC 100 rating.
Solar water heating systems have two main components: solar collectors and well-insulated storage tanks. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don't. In some systems, the solar water heater preheats water before it enters the conventional water heater. In others, the back-up heater is combined with the solar storage in one tank.
Passive solar domestic water heating systems are simple systems that require no pumps or sensors. On a sunny or bright overcast day, the sun heats water that moves by convection from a solar thermal collector to a conventional water heater or a heat exchanger in the water heater.
Active solar water heating systems enable the solar collector to be placed on the roof and they are often a better choice in cold climates. Most have: a solar collector to capture solar energy; a storage tank; a circulation system to move water (or water containing food-grade antifreeze) between the collector and a storage tank; a backup heating system; and a control system.
Besides being inexpensive to install and virtually free to operate, solar hot water systems are comfortable, safe, clean, reliable, quiet and healthy.
For more information visit http://www.eere.energy.gov/RE/solar.html
