In the present work, investigations are made to study performance characteristics of solar flat plate collector with PCM and nanofluids . Flat plate collector is one of the important solar energy trapping device which uses as air or water as working fluid. In this work we designed and fabricated the flat plate collector for the commercial application, it is capable of using both the diffuse and the direct beam solar radiation, For residential and commercial use , flat plate collectors can produce heat at sufficiently high temperatures to pre heating water for boiler and to heat swimming pools , domestic hot water , and buildings , they also can operate a cooling unit , particularly if the incident sunlight is increased by the use of reflector .Temperatures upto 45 C are easily attained by flat plate collectors. We are going to test the performance of the flat plate collector with outlet temperature of water without using PCM and using PCM (Zn(NO3)2.6H2O) and nano fluid (Al2O3).By obtaining the values and compare the rate of heat transfer.