Solar Batch Heaters

For a hundred years, simple solar batch heaters have been used in the United States. The term ICS (integrated collector storage) tells us that the collector and storage tank are combined into one unit. A tank of water, enclosed in an insulated box covered with glass, is placed in the sun facing south. Cold water is piped to the bottom of the tank; hot water is taken off the top. Whenever there´s a call for hot water, water pressure from the home moves hot water from the top of the solar batch heater as cold water is pushed into the bottom.

Since the potable water is heated directly, this is an open-loop system. And since no pump is used to move the water from collector to end use, it is passive. The batch heater is a popular choice for homes in moderate climates where freezing is not much of an issue. Commercially manufactured batch heaters are relatively low cost. Crude batch heaters can even be homemade. If batch heaters are installed on the roof, weight has to be taken into account. Commercial batch heaters can weigh 200 pounds (90 kg) dry, and when filled with 40 gallons (150 l) of water, more than 320 pounds (145 kg) is added.

Because of their relatively low cost and simplicity, for those living in moderate climates with good sunshine available, the batch heater is probably the best value for heating domestic water.

The illustration includes the primary components of any solar batch heater system.