Experimental and numerical study on steady-state thermal performance of a kilowatt-scale chloride salt receiver prototype for the next-generation solar power tower

The design approach and thermal performance evaluation are crucial for ensuring safe and efficient operation of high-temperature chloride salt receivers in the next-generation solar power tower. In this study, a kilowatt-scale chloride salt receiver prototype was developed by the optical-thermal coupled design methodology, and then a high-temperature chloride salt loop experimental platform was constructed. Numerical and experimental studies were performed to investigate individual and coupled effects of inlet temperature, flow rate and incident energy on the steady-state thermal performance of the receiver prototype. Moreover, practical insights in the construction and operation of the platform were summarized. Within the temperature range of 609–723 ℃, results indicate that the absolute deviations between the experimental and simulated outlet temperatures of the receiver prototype range in 0.31–0.64 %, proving the reliability of the adopted optical-thermal coupled model. As the inlet temperature increases, the radiative loss proportion increases from 60.69 % to 67.17 %, confirming its dominant role. At higher flow rates, the enhancement of vortex mixing increases the total, radiative and convective by up to 40.92 %, 45.63 % and 31.88 %, respectively. As the incident energy increased from 0.96 kW to 1.99 kW, the receiver efficiency increases by 0.95–4.07 %, which is more sensitive to the flow rate than the inlet temperature. A dual-diaphragm flange structure with an orifice plate and a stepwise preheating procedure was proposed for flow rate measurement and reliable steady-state testing, respectively. This study offers data support for numerical research and provides guidance for the design and operation of the high-temperature chloride salt receiver.