Solar energy is become an alternative for the limited fossil fuel resources. One of the simplest and most direct applications of this energy is the conversion of solar radiation into heat, which can be used in water heating systems. A commonly used solar collector is the flat-plate. Flat Plate Collector (FPC) is widely used for domestic hot-water, space heating/drying and for applications requiring fluid temperature less than 100 0 C. Three main components associated with FPC namely, absorber

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... ate, top covers and heating pipes. The absorber plate is selective coated to have high absorptive. It receive heat by solar radiation and by conduction; heat is transferred to the flowing liquid through the heating pipes. The fluid flow through the collector pipes is by natural or by forced circulation (pump flow). For small water heating systems natural circulation is used for fluid flow. Conventionally, absorbers of all flat plate collectors are straight copper/aluminum sheets however, which limits on the heat collection surface transfer area.The performance of any solar collector is largely affected by various parameters such as Glazing (single glazing and double glazing), Absorber plate, Top covers and Heating pipes. The absorber plate of the FPC transfers solar energy to liquid flowing in the tubes. The collector efficiency is dependent on the temperature of the plate which in turn is dependent on the nature of flow of fluid inside the tube, solar insulation, ambient temperature, top loss coefficient, the emissivity of the plate and glass cover, slope, etc.