Concentrated solar tower hybrid evacuated tube–photovoltaic/thermal receiver with a non-imaging optic reflector: A case study

Abstract This work aimed to describe the performance of evacuated tubes (ETs) and assess their use as a receiver in a solar tower. Two experimental cases were evaluated. In Case 1, the MATLAB code was developed and used in a transient simulation of the evacuated tube receiver. Based on the results of the simulation of the receiver, the model has been experimentally tested with a staggered distribution were used to determine thermal performance. In Case 2, solutions for the spillage losses that occurred in Case 1 were provided through a hybrid system that used ETs, monocrystalline solar cells with liquid water cooling, and secondary concentrators. Electrical energy and heat were generated as by-products by a concentrating photovoltaic/thermal (PVT) system. The best overall properties were achieved with a hybrid receiver in Case 2. Specifically, these properties included a heat transfer fluid (HTF) temperature of 153 °C at the outlet of the receiver, a heat gain of 10 kW, and a receiver efficiency of 60%. Relative to Case 1, Case 2 achieved an improved receiver performance with the increase in concentration ratio (secondary concentrators). The average HTF temperature, heat gain, and receiver efficiency were 6.2%, 11.5%, and 9.3%, respectively. For the PVT system, the maximum temperature of the photovoltaic coolant outlet was 51 °C. The maximum thermal power was 905 W, which corresponded to the maximum thermal efficiency of 46%. Maximum electric power and electrical efficiency were obtained at approximately 127 W and 6.2%, respectively. Results showed that the hybrid ET–PVT receiver with a non-imaging optic reflector technology exhibits a high potential for improving overall power generation efficiency.