Active systems use pumps to circulate water or other heat transfer
fluid through the system. When sunlight heats one or more solar
collectors sufficient for water heating, sensors and a controller
activate a pump to circulate a fluid - either potable water from the
storage tank or a food-grade antifreeze solution in climates exposed to
freezing conditions.
An active system also has a flat-plate
collector on the roof and a solar storage tank which is usually located
in a garage or utility room. An electric pump circulates the water
between the collector and the indoor solar storage tank whenever solar
energy is available and needed to increase the temperature of the water
in the solar storage tank.
|
