Influence of geometric design variables on the performance of a novel V-shaped cavity receiver

This study presents a novel cavity receiver for parabolic trough concentrators, incorporating a triangular envelope, a trapezoidal cavity, and a semi-circular flow channel. A total of 5120 designs were examined by tuning the rim angle of parabolic mirrors, the width and angle of the receiver's opening, and the depth of the absorber for different operating flow rates and temperatures. Batch simulations of these designs were automated by coupling newly developed and validated models of Monte Carlo ray tracing and semi-analytical 1-D energy balances in SOLTRACE® and MATLAB® to determine the heat fluxes and surface temperatures of the receiver, respectively. The results show that the rim angle must be reduced to maximize sun rays' interception, and the opening angle has the largest impact on performance. All dimensions must be decreased when operating at low flow rates and high temperatures to avoid excessive thermal losses. This results in maximum energy and exergy efficiencies of 74.7 % and 40.7 %, respectively. When operating at low temperatures and large flow rates, the largest energy and exergy efficiencies increase and decrease to 80.5 % and 27 %, corresponding to optimal rim angle, absorber depth, opening width, and opening angle of 60°, 85 mm, 200 mm, and 100°, respectively.