Solar water heating is a clean, reliable and cost-effective technology that can reduce the utility bills of thousands of homes and businesses. Today, people across the country are manufacturing and installing these systems, which greatly reduces our dependence on imported fuels. We need smart policies to expand this fast-growing job-creating industry.
Solar heating includes solar heating and cooling technology, as well as solar swimming pool heating, solar space heating, solar cooling and solar industrial process preheating. In short, a solar hot water system collects heat from the sun and uses it to heat water for home or business use instead of using electricity or natural gas.
The solar hot water system 1 can be installed in every home in the United States and consists of three main elements: solar collectors, insulated pipes and hot water storage tanks.
It can also include electronic controls and antifreeze systems for cold climates. Solar collectors collect heat from solar radiation and transfer the heat to drinking water. This hot water flows from the collector to the hot water tank and is used when necessary. This type of system is called an open loop system or a direct system. If necessary, the auxiliary heater can remain connected to the hot water tank for later use.
In cold climates, the temperature may freeze, so an indirect system is used. . The antifreeze solution (such as non-toxic propylene glycol) is heated in the solar collector and circulated to the hot water storage tank through the heat exchanger. The portable water in the storage tank is heated by a thermal heat exchanger filled with antifreeze, and then hot water can be used as needed, while the cooled glycol is transported back to the solar collector for reheating.
Another common solar water heating system design for cold climates is called "drainage." This type of solar system usually uses water as a heat transfer fluid and is designed to allow all the water in the solar collector to "drain" back into the water storage tank in the heated part of the building that uses it. When there is no sunlight for heating, the solar pump will shut down and water will flow into the drain tank due to gravity.
No matter which type of solar system is used, a properly designed and installed solar water heating system can meet a large part (40% to 80%) of the building's hot water demand.