Effect of aspect ratio on thermal performance of cavity receiver for solar parabolic dish concentrator: An experimental study

Abstract

Proper design of the receiver is vital to maximize the performance of solar parabolic dish concentrator. In this paper, an experimental study on the thermal performance of the conical cavity receiver with different aspect ratios for solar parabolic dish concentrator is presented. The receivers of aspect ratio 0.8, 1.0 and 1.2 are constructed for a given cone angle and tested in bright sunny days with average beam radiation above 600 W/m2. The energy efficiency, exergy efficiency and overall heat loss factor of the receivers were evaluated and compared. As expected, the receiver surface temperature got reduced with increase in aspect ratio. However the thermal performance is observed to decrease. The receiver with aspect ratio of 0.8 shown highest performance among all the receivers tested. It is revealed that reduction in receiver surface temperature alone is not adequate to improve the thermal performance, the surface area is also an influencing factor. Hence the aspect ratio of the receiver has a significant impact on the thermal performance and should be carefully chosen while designing the receiver. The results presented in this work are useful for further optimization of the receiver design.