Solar Energy is the major source of energy, and utilization of it requires solar collectors. A device generally called solar concentrator is used. Concentration of solar energy can be done by using either reflecting or refracting elements, which are so positioned that, solar flux is directed on the absorber. With the help of a flat plate collector, it is possible to get temperature around 100oC to heat liquids or gasses. There are several processes operating at much above 100oC, where high energy is required. This can be achieved by using concentrating collectors. Solar parabolic trough collector is currently used for the generation of electricity and applications with relatively higher temperatures. Parabolic trough collectors are typically operated at temperatures above 250 oC. An attempt is made in this project to develop a parabolic trough collector for water heating more effectively as compared to the flat plate collector. Thermal analysis procedure of a solar parabolic trough collector design starts with the selection of certain parameters such as aperture area and diameter of receiver to obtain the geometric concentration. In this investigation, experimentation is based on varying concentration. An experimental parabolic trough collector with aperture 1.2 m, focal height 0.3 m and trough length 3 m is constructed. A G.I pipe having inner diameter of 25.4 mm and outer diameter of 28 mm placed at the focal axis is used as receiver.
