Experimental investigation of the thermal efficiency of a new cavity receiver design for concentrator solar technology

Abstract

The most popular design for solar energy receivers that achieves great thermal performance is a cavity receiver. This study experimentally compared two novel shapes of cavity receivers: conical-cylindrical-conical (CCC) and double cylindrical, with conventional conical and cylindrical designs, to examine the effectiveness of solar energy receivers. The findings indicate that the CCC shape demonstrated a higher level of efficiency, as it performed better than all other shapes that were examined. Results emphasized the influence of radiation intensity on receiver efficiency, with all shapes exhibiting improved performance at higher intensities, maximizing at 1000 W/m2. Lower friction factors were desirable for minimizing heat losses and maximizing efficiency, resulting in values of 0.078, 0.09, 0.1, and 0.12 for CCC, conical, double cylindrical, and cylindrical shapes at a flow rate of 2 L/min, respectively. The temperature differences for CCC, conical, double cylindrical, and cylindrical shapes are computed as 6.4 degrees C, 5.7 degrees C, 5 degrees C, and 4.3 degrees C, respectively. The thermal efficiencies of the CCC, conical, double cylindrical, and cylindrical shapes are computed as 86.5 %, 81.5 %, 79.9 %, and 68.9 %, respectively, at a flow rate of 2 L/min.