Dimensioning and efficiency evaluation of a hybrid photovoltaic thermal system in a tropical climate region

Abstract

This paper analyses the performance of photovoltaic thermal (PVT) panels in tropical climate regions. In PVT systems, a heat exchanger is coupled to conventional photovoltaic (PV) panels, making possible to improve the efficiency of the PV panels and to provide heat: The decrease in the PV cell temperature increases the electrical power produced, whereas the heat absorbed can be used in low temperature applications, such as water heating or air conditioning. In this research paper, the main factors that affect PVT systems performance are deeply studied in order to choose the most suitable set of parameters for a tropical climate operation based on technical and economic aspects. The combined use of Digital logic and merit index methods are applied to the heat exchanger material selection. The performance analysis of the other constructive aspects and operational variables are conducted through a numerical simulation using the thermal resistance model solved by trust region method via a class of dogleg paths and validated by experimental results. Using real weather data, the performance is compared with respect to a conventional PV system over a full day period. The results have shown a significant improvement in efficiency: In the worst case, the 12.53% average electrical efficiency of the PV system is increased to 29.06% for a PVT system (12.55% electrical plus 16.51% thermal efficiency). In the best case, an average overall efficiency of 41.83% was achieved by PVT, demonstrating the ability of PVT to increase the energy capture from solar radiation and showing that the performance is improved by selecting carefully those factors.