Numerical simulation on the thermal performance of a solar molten salt cavity receiver

Abstract

The receiver thermal performance directly affects the efficiency, reliability and safety of the entire solar tower power system. A model combining radiation, convection and conduction heat transfer modes was developed to model a 1 MW molten salt cavity receiver with determined basic design parameters. The coupled heat transfer model was used to predict the receiver's steady-state efficiency, temperature distribution and heat losses for various flow layouts and receiver aperture lip sizes.The results show that the fraction of reflective loss (18.78%) is the largest in all heat losses, followed by radiative and convective heat losses, with conduction heat losses as the smallest part which is usually negligible. The heat loss distribution is closely related to the external tube temperature field in the cavity receiver and the specific structure of the receiver. 10 cm lips on both the top and bottom of the receiver aperture reduced the reflective heat loss by 1%. The results for different flow layouts show that center-side flow layout has the best temperature homogeneity, with less possibility of overheating in the central area. This, however, comes at the expense of increased irreversibilities and decreased efficiency. The sides-center flow layout has the worst temperature homogeneity, but the receiver efficiency is 2.06% higher. These results provide a useful reference for designing and optimizing cavity receivers.