How does a Solar Water Heater work? What are the different types of SWH?
There are 2 types of SWH – Flat Plate Collector (FPC) and FPC SWH – The solar radiation is absorbed by flat plate collectors which consists of a metal box covered on top with a glass sheet. Selectively coated blackened metallic absorbers form the bottom part of the box. The sides and bottom are insulated to minimize heat loss. The absorber consists of riser tubes to carry water. The absorber plate absorbs the solar radiation and transfers the heat to the flowing water through the riser tubes to the insulated storage tank Evacuated Tube Collector ( ETC) water heaters. ETC SWH – The collector is made of double layer borosilicate glass tubes evacuated for providing insulation. The outer wall of the inner tube is coated with selective absorbing material. This helps absorption of solar radiation and transfers the heat to the water which flows through the inner tube. The vacuum within the evacuated tubes reduce conducted heat losses.
