Effect of the concentration ratio on the thermal performance of a conical cavity tube receiver for a solar parabolic dish concentrator system

Abstract

The proper design of the parabolic dish concentrator system and the accurate selection of variable operating parameters are critical in solar energy conversion and utilization. This paper comprehensively studied the design, simulation, and experimental thermal performance of a conical cavity tube receiver for parabolic dish concentrators at various concentration ratios to maximize thermal efficiency. The receiver was examined at a temperature variation of 20–130 °C with water as the working medium under a flow rate of 0.45 L per minute. The experimental testing was performed at different concentration ratios of 10.38, 20.76, and 31.15. The conical receiver's average exergy efficiency and energy efficiency were estimated to be 8.16% and 65.81%, respectively, within the highest concentration ratio of 31.15. The difference in temperature of the heat transfer fluid at the intake and exit of the receiver has a similar variation pattern to the energy efficiency of the receiver. In addition, the parabolic dish concentrator system with a conical cavity copper tube receiver was designed and simulated using COMSOL Multiphysics® to obtain the temperature distribution of the receiver with different concentration ratios, flux distribution in the focus of the plan, and incident heat flux on the receiver surface for real reflectors. The simulation results were compared with the experimental results, and a satisfactory agreement was achieved. The findings from this study are helpful for further parabolic dish concentrator system design optimization. The results indicate that this lightweight, highly efficient, and low-cost solar receiver has the capacity to be utilized with a solar parabolic dish-type concentrating system for thermal processes.