Performance Evaluation and Optimization of a Novel System Combining a Photovoltaic/Thermal Subsystem & an Organic Rankine Cycle Driven by Solar Parabolic Trough Collector

A novel coupling system that combines a photovoltaic/thermal(PV/T) subsystem and an Organic Rankine Cycle(ORC) driven by solar parabolic trough collector(PTC) is presented in this paper. The mathematical model is initially built. On the basis, the influence of area ratio of two collectors(PV/T and PTC) on the performance of system is discussed. The results show that the optimal area ratio of PV/T to PTC is 8:2, which can achieve the maximum energy output. Moreover, the performance of the coupling system and two independent systems(PV/T and ORC system) are compared and analyzed. The results show that the coupling system is more reliable and its total output energy(heat and electricity) is the highest, compared with the other two independent systems. The solar energy utilization efficiency of the coupling system is 40% higher than that of the other two independent systems in the steady-state simulation. Moreover, the annual output energy per unit area collector of the coupling system is 13% higher than that of the other two independent systems in the dynamic simulation. Furthermore, in the dynamic simulation of a typical day, the PV panels’ temperature of the coupling system is 5°C–7°C lower than that of the independent PV/T system. It means that the power generation efficiency of PV panels can be increased by 1.5%–3.5%. This study aims to explore the operation characteristics of the novel solar energy utilization coupling system and promote the development of renewable energy utilization models, which provides a reference for the design and optimization of related energy systems.