Thermal Analysis of a Concentrating Photovoltaic Receiver

Abstract

This paper presents the theoretical and computational analysis for a photovoltaic (PV) receiver for the Science Applications International Corporation (SAIC) dish concentrator. During photovoltaic energy conversion, thermal energy is also generated which results in increases in cell temperature. However, as the cell temperature increases, the efficiency of the PV cells drops—a 40°C increase in temperature for this unit cuts performance by 25%. An algorithm has been developed to predict the maximum cell temperature and working fluid temperature as a function of channel size, mass flow rate, cooling configuration, fluid-to-tube heat transfer coefficient and other parameters. To evaluate the transient characteristics of the system, a dynamic model of the concentrating PV collector has been developed. The model describes the change in temperature of the cells and the coolant in the receiver as a function of time, taking into account the: solar insolation, change in energy content of the element, energy transfer by the fluid flow, and temperature dependent energy flow between the element and the surroundings. Five energy balance differential equations have been solved simultaneously to examine the transient nature of the system. Computational fluid dynamics flow modeling (CFD) software has also been utilized to compare the temperature distribution along the module with the analytical results. The flow model is built and applied mesh using the preprocessing tool, GAMBIT, and the CFD analysis has been done by using Fluent. The model quantifies temperature, velocity and pressure profiles of the module.