After the sun heats the liquid, it travels to a tank in the home where it heats stored water. Most systems use pumps to move the liquid.
Among the benefits of solar hot water:
A typical household can meet 50 to 80 percent of its hot water needs with a solar thermal system. Costing several thousand dollars, solar thermal systems are less expensive and have a quicker payback than solar electric systems. Once paid for, they offer the free fuel of the sun’s heat. Systems that are properly installed and regularly maintained can operate up to 30 years with minimal costs.
Photo Courtesy of DOE/NREL, Solar hot water heater panels installed on the Thermal Test Facility (TTF)
Installing a solar hot water system provides the satisfaction that you are doing your part to use renewable sources of energy and extending our current energy supplies, while reducing carbon emissions and environmental pollution. A domestic water system can offset the equivalent of about 40% of the carbon dioxide emissions of a car.
Solar hot water heating systems
The most popular solar collectors for hot water heaters use a flat panel design. A flat panel collector is an insulated weatherproof enclosure with an absorber plate, flow tubes, and a transparent cover. Once the liquid is heated by the sun, it is usually pumped to a storage tank, where heat exchangers transfer heat from the fluid to the household water.
Other systems are available, and hot water systems specifically designed for pools or spas make sense for some consumers.
More information about different types of solar hot water heaters is available here: (http://www.coseia.org/newsite/index.php?id=115)
Deciding if solar hot water is right for you
The solar panels needed will depend on how much hot water you use, the type of panels, the estimated efficiency and other factors. And to work well, panels should be tilted at latitude and facing due south.
In general, the most efficient systems are sized to meet your hot water needs on the sunniest days under optimal conditions so that you don’t over-size your system.
Qualified installers can give you an individual assessment and help you design the optimal system.
Questions to ask contractors
The solar hot water industry developed a black eye in the 1970s when tax credits made for soaring demand and unscrupulous contractors entered the market. Now consumers have more ways to check up on the contractors they are considering by asking questions such as:
--Have they been certified by a state association such as the Colorado Solar Energy Industry Association (COSEIA)?
--Do they have ample references of satisfied customers and a clean record with the Better Business Bureau?
--Have you verified that they have necessary licenses and insurance?