Coupled optical and thermal simulation of the thermal performance of a 50 MWe external cylindrical solar receiver

The performance of the central receiver is directly related to the efficiency and power generation capacity of the solar tower power plant. In this paper, by combining the analytical approximation method and the finite volume method, the coupled optical and thermal performance of a 50 MWe external cylindrical receiver was numerically evaluated. The thermal performance of the receiver under design parameters was first simulated, and the model was verified by the comparison with the method in Zhou et al. [Renewable Energy 164, 331–345 (2021)]. The effects of key parameter and uniformity of incident flux distribution on the thermal performance were then extensively investigated. Finally, the thermal performance changes in one day were explored. The results showed that direct normal radiation (DNI), salt inlet mass flow, salt inlet temperature, and coating absorption rate strongly affected the receiver's thermal performance. Compared with the non-uniform incident flux distribution, the accurate salt outlet temperature could also be obtained under the uniform incident flux distribution, but the thermal efficiency was underestimated by 0.5%, and the wall temperature on the front side of the tube was generally underestimated, reaching 5.6% at the location of the maximum wall temperature. Evolution trend of the salt outlet temperature and maximum wall temperature on vernal equinox was similar to that of the DNI distribution. From 14:00 to 18:00, they decreased by 18.3% and 12.3%, respectively. The maximum wall temperature from 13:00 to 16:00 exceeded the design value of 700 °C, which was detrimental to the safe operation of the receiver and might cause decomposition of molten salt in the tube.