Solar heating harnesses the power of the sun to provide solar thermal energy for solar hot water, solar space heating and cooling and solar pool heaters.
Solar Water Heating
Most solar water heating systems have two parts, a solar collector and a storage tank. The solar collector gathers the sun’s energy, transforms it into heat then transfers the heat to water. The heated water is then stored in the storage tank for later use, with a conventional system providing additional heating as necessary. Solar water heating systems can be either active (relying on electric pumps to circulate water) or passive (relying on gravity and the tendency for water to naturally circulate when heated), but the most common type for use in commercial and residential buildings is active.
The Value Proposition of Solar Water Heating in California, a study released by the California Solar Energy Industry Association (CALSEIA), quantifies the value of solar water heating and demonstrates how consumer rebates will pay for themselves many times over in the form of energy savings, cleaner air and economic development.
Solar Space Heating and Cooling
Active solar space heating systems collect and absorb solar energy and use electric fans or pumps to transfer and distribute the heat. These systems also contain an energy-storage system to provide heat at night or when the sun is not shining. Passive solar space heating capitalizes on warmth through the sun through design features as well as materials in the walls or floors that absorb heat during the day and release that heat at night.
Perhaps the most interesting new solar thermal technology is the absorption chiller – a closed-loop system that converts solar-heated water into air conditioning. Water heated by the sun through flat-panel collectors or evacuated tubes is subjected to a low-pressure loop with lithium bromide, a phase-change catalysts, which causes the water to reach a cool 44 degrees F. This cooled water runs through copper piping; forced air passing over the coils produces air conditioning.
Solar Pool Heating
Solar pool heating systems use the existing pool filtration system to pump the water through a solar collector and the collected heat is transferred directly to the pool water. Solar pool heating collectors typically operate at a slightly warmer temperature than the surrounding air and normally use unglazed, low-temperature collectors made from polymers.