An experimental study on energy and exergy performance of a cavity receiver for solar parabolic dish concentrator

In this paper, an experimental study is carried out to investigate the thermal performance of a conical frustum cavity receiver for a 16 m2 Scheffler concentrator, using energy and exergy analyses. The experiment is conducted with heat transfer fluid having a flow rate of 2.5 litres per minute (LPM) under an average beam radiation of 608.17 W/m2. The average thermal energy efficiency of the receiver is found to be 57.39% with a peak value of 66.75%. The receiver could attain a very low overall heat loss factor of about 0.027 kW/K. The overall system efficiency of the solar collector is 69.47%. The average exergy efficiency of the receiver is found to be 5.88% with a peak value of 10.35%. A peak exergy factor of 0.152 is obtained for the receiver. Experiments are also conducted with flow rates of 1, 1.5 and 2 LPM in addition to the flow rate of 2.5 LPM and the receiver showed better performance for 2.5 LPM.