Solar Water Heaters have several advantages over conventional water heating systems as they:
There are two types of Solar Water Heating Systems -
1. Evacuated Tube Collector Solar Water Heater
Solar Water Heater (ETC System) works on a simple principle 'Black body heat absorption principle'. The principle says, 'black colour absorbs maximum heat, more than any other colour'. Solar water heating systems using vacuum tubes made of borosilicate glass with special coating to absorb the solar energy are called as Evacuated Tube Collector system (ETC Systems).
Evacuated Tube Collector Solar Water Heater Features:
2. Flat plate Collector Solar Water Heaters
Flat Plate Solar Collectors is the earlier technology used in Solar Water Heating Systems; however they are still today the most efficient & reliable for Solar Water Heating Systems. Under soft water conditions they have a life of 20 years & more.. Flat Plate Collectors have been carrying the prestigious ISI Mark..
A typical flat-plate collector is a metal box with a glass or plastic cover (called glazing) on top and a dark-colored absorber plate on the bottom. The sides and bottom of the collector are usually insulated to minimize heat loss.
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.
Absorber plates are commonly painted with "selective coatings," which absorb and retain heat better than ordinary black paint. Absorber plates are usually made of metal-typically copper or aluminum-because the metal is a good heat conductor. Copper is more expensive, but is a better conductor and less prone to corrosion than aluminum. In locations with average available solar energy, flat plate collectors are sized approximately one-half- to one-square foot per gallon of one-day's hot water use.