THE EXPERIMENTAL STUDY ON THE EFFECT OF MASS FLOW RATE AND ORIENTATION ON THE PERFORMANCE OF A CPC SOLAR COLLECTOR

The experimental Study on the effects of mass flow rate and orientation on the performance of a CPC solar water heater collector is presented. The system consist of a cylindrical solar radiation concentrator with a black coated tubular absorber positioned along its axis, a cold water tank positioned above the collector and a hot water tank below it such that fluid flows into it by gravity and out of it by thermo-syphon effect. Valves are used at strategic points on the connecting pipe lines to isolate the flow of water. The system was tested at three different mass flow rates of 0.001 kg/s, 0.002 kg/s and 0.003 kg/s. respectively and at different orientaions. The Results obtained revealed that a maximum outlet water temperature of 69.5ºC was obtained at a solar intensity of 1027 W/M2 on 07/02/2013 and a maximum instantaneous efficiency of 51.01% was obtained when the system was oriented in the east-west direction corresponding to the mass flow rate of 0.001 kg/s. The maximum temperatures for the 0.002 kg/s and 0.003 kg/s are 66.5ºC and 64.5ºC respectively. The above observation, could be attributed to the fact that at lower flow rates, the critical water retention time is greater at lower flow rates. Hence, the water stays at the absorber tube longer for lower flow rates. This consequently resulted in the higher temperature recorded.