Principle:
A glazed flat-plate solar collector consists of a shallow
rectangular box with a flat black plate behind a tempered glass
cover. The plate is attached to a series of parallel tubes or one
serpentine tube through which water or another liquid (such as an
antifreeze solution) passes. Sunlight passes through the glazing
and strikes the absorber plate, which heats up, changing solar
energy into heat energy. The heat is transferred to liquid passing
through pipes attached to the absorber plate. Sunrain Absorber
plates are commonly painted with selective coatings. As the liquid
circulates through the system, it absorbs the heat from sunlight
falling on the collectors. The heated liquid then enters a heat
exchanger or is added directly to the conventional system. In
commercial applications, the solar-heated water flows to a storage
tank that is connected to the conventional water heating system.
Although flat-plate solar collectors could mainly be used under the
circumstance of the temperature above zero centigrade as they are
less efficient in cold weather than in warm, sunrain system is best
suited to applications that require medium to high temperatures
.
