Solar Water Heaters

Active Systems - Open Loop

Open-Loop Active Systems use pumps to circulate household water through the collectors. This design is efficient and lowers operating costs but is not appropriate if your water is hard or acidic because scale and corrosion quickly disable the system.

These open-loop systems are popular in nonfreezing climates. They should never be installed in climates that experience freezing temperatures for sustained periods. You can install them in mild but occasionally freezing climates, but you must consider freeze protection.

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. Consider recirculation systems only where mild freezes occur once or twice a year at most. Activating the freeze protection more frequently wastes electricity and stored heat.

Of course, when the power is out, the pump will not work and the system will freeze. To guard against this, a freeze valve can be installed to provide additional protection in the event the pump
doesn’t operate. In freezing weather, the valve dribbles warmer water through the collector to prevent freezing.

Open Loop - Complete Solar Systems:
Helio-Flo
Alternate Energy Technologies
Solene Chromagen
SunEarth

Single Collectors:
Gobi Solar Collector
Alternate Energy Technologies
Chromagen Solar Collector
SunEarth Solar Collector

A typical solar water heater system components and layout is shown below (Shown with Flat Plate Collector):