Thermal Simulation of Low Concentration PV/Thermal System using a Computational Fluid Dynamics Software

Cogenra company has created a low concentration PV/Thermal system that produces both thermal energy and electricity simultaneously, mainly for commercial and industrial applications. The realization of a system that combines photovoltaic modules, solar thermal collectors and concentrating mirrors makes it a complicated system to study. So far, only simple studies have been made on Cogenra’s LCPVT system including a 2-dimensional model. In this project, the possibility of using a Computational Fluid Dynamics software for analysing the low concentration PV/Thermal system of Cogenra has been studied. The CFD software Ansys Fluent has been used, in which a model was created in accordance to the Cogenra LCPVT system. After validating the results, the model has been used for analysing the system’s performance under various conditions in order to realize the system’s losses. Furthermore, due to the numerous components of the system, the analysis of the LCPVT system becomes a multi-variable problem. For this reason, three main parameters (mass flow rate, optical concentration, PV type) that affect the system’s performance has been chosen and studied in order to improve the system’s overall efficiency. Since the system has both electrical and thermal outputs, an equivalent efficiency was determined to express the two different efficiency terms. For the purpose of comparing the performance of the LCPVT system with the traditional photovoltaic modules, one other simple model was created in Ansys Fluent. This model has also been simulated under the same conditions as the Cogenra system in order to observe the difference in output between the LCPVT system and the photovoltaic modules. The low concentration PV/Thermal system has also been compared with other solar thermal systems such as a PV/Thermal system, a Concentrated Thermal system and a simple Solar Thermal System.