Active Solar Hot Water Systems

Active Systems

Active systems use electric pumps, valves, and controllers to circulate water or other heat-transfer fluids through the collectors. They can be more expensive than passive systems but are also more efficient. Active systems start at $4,000 installed.

Open-Loop Active Systems

Open-loop active systems use pumps to circulate household water through the collectors. Recirculation systems are a specific type of open-loop system that provide freeze protection. They use the system pump to circulate warm water from storage tanks through collectors and exposed piping when temperatures approach freezing.

Closed-Loop Active Systems

These systems pump heat-transfer fluids (usually a glycol-water antifreeze mixture) through collectors. Heat exchangers transfer the heat from the fluid to the household water stored in the tanks. Closed-loop glycol systems offer good freeze protection. However, the glycol must be checked each year and changed every 3 to 10 years, depending on glycol quality and system temperatures.

Drainback systems use water as the heat-transfer fluid in the collector loop. A pump circulates the water through the collectors. The water drains by gravity to the storage tank and heat exchanger; there are no valves to fail. When the pumps are off, the collectors are empty, which assures freeze protection and also allows the system to turn off if the water in the storage tank becomes too hot.

Click Here for a Spec Sheet of the SunEarth Empire Collector.


Empire Collector Cutaway.