Optical and thermal analysis of different cavity receiver designs for solar dish concentrators

Cavity receivers are the most usual design in solar dish concentrators in order to achieve high thermal performance. The objective of this work is the investigation of five different cavity receivers under different operating temperature levels and the selection of the most appropriate designs. More specifically, the examined cavities have the following shapes: cylindrical, rectangular, spherical, conical and cylindrical-conical. All the cavities are optimized in order to determine the best design which maximizes the thermal efficiency of the solar collector. The optimization variables are different for every design and they regard the cavity length, the cone angle and the distance from the concentrator base. According to the results, the best design is the novel one with cylindrical-conical shape, while the conical and the spherical are the next choices. The worst design is rectangular, while the cylindrical is the fourth design in the performance sequence. For operation at 300 degrees C, the cylindrical-conical design is found to have 67.95% thermal efficiency, 35.73% exergy efficiency while the optical efficiency is 85.42%. The analysis is conducted with a developed model in SolidWorks Flow Simulation which is validated with literature experimental data.