ABSTRACT
Solar thermal uses the sun's heat to create hot water. Collectors are placed on the roof and connected to a storage tank. The storage tank hot water is then used to feed the hot water heater instead of cold water, reducing or eliminating the time the heater needs to run. Solar thermal hot water heating is used for heating pools, domestic hot water (DHW), radiant heating, and manufacturing. There are two basic types of system layouts: drain-back and closed loop. These have similar components but use different transfer fluids in their system piping. The size of the collectors and storage is based on hot water usage, desired water temperature, and available solar insolation. The designer needs to account for placement of the collectors on the roof, the location of piping connecting the collectors to the tank as well as the tank and various pumps and controls.
