Abstract: This paper present the concept of saving the energy in domestic heating system. In this paper we compare the three different types of domestic solar water heating system with different collectors are flat plate collector without heat exchanger (FPC), flat plate collector with heat exchanger (FPCHE) and evacuated tube type collector (ETC). The first system consists of FPC (2.07m²) connected to a 100 liters of storage tank. The other system consists of FPCHE having an area of (1.836m²) and the ETC having an area of (1.358m²) are both connected to 100 liters of storage tank, corresponding to several nice sunny days at Solar Energy Centre. The average temperature in the tank of FPC reached to a maximum of 58^oC starting from an initial temperature of 25^oC in the morning, while the average tank temperature in the FPCHE is 48^oC starting from the same initial temperature. Similarly in the ETC the average temperature in the tank is 49^oC with the same initial temperature. The efficiency of the FPC was observed to be around 40% and for FPCHE, it was observed to be around 48% while it was observed to be around 51% for the ETC.

Keywords: Flat plate collector without heat exchanger, flat plate collector with heat exchanger, evacuated tube collector, efficiency.