Performance evaluation of a solar photovoltaic thermal air collector using energy and exergy analysis

Abstract

In this article, a comparative study is carried out between two equations for the exergy efficiency of photovoltaic thermal (PVT) air collectors; the first equation is based on net output exergy and the second equation is in terms of exergy losses. The exergy efficiency equation parametrically is dependent on thermal and electrical parameters of PVT air collector; therefore, improved thermal and electrical models are used to calculate them. Developing an exergy balance for PVT air collector system, the various exergy components in PVT system are introduced and two equations for the exergy efficiency of PVT air collector are derived. A computer simulation program is also developed which is based on the used improved thermal and electrical models. In order to validate the simulation results, a typical PVT air collector has been built and some experiments have been carried out on it. The results of numerical simulation are in good agreement with the experimental results. Finally, parametric studies have been carried out and the effect of design and climatic parameters on two exergy efficiency equations has been investigated. It is observed that the improved exergy efficiency obtained in this paper is in good agreement with the one given by the previous literature and it is better because it shows the portion of each of exergy losses in the exergy efficiency equation, directly. © 2011 American Institute of Physics.