Solar Energy Collectors
1. Flat Plate Collector.
4. Tubes or channels to circulate the liquid required to remove the heat energy from the collector to the strong tank.
(1) particles of copper oxide about 1 u m in diameter,
(2) semi- conductor like silica
(3) layered coatings of calcium oxide and magnesium oxide.
These coating have a high ratio of absorptive emissivity (about 10 to 15 or so) but are very expensive. Al though a variety may be used for the heat transfer in the collector flow channels. All practical system to date have used water or water ethylene glycerol solution, the letter additive being used primarily to avoid problem due to the freezing of liquid in the tube under subzero temperature conditions. it is very simple and less costly type solar energy collectors.