D. Chemisana1* , J. Cipriano, M. Ibanez, B. Abbdel Mesih, A. Mellor

1 University of Lleida, 25001 Lleida, Spain.

Daniel Chemisana, daniel. chemisana@macs. udl. cat

Abstract

This paper presents the thermal evaluation of an evacuated PVT collector designed to operate under concentrated radiation (15 suns). Finite volume 3D numerical computations have been carried out in order to study the thermal characteristics of different rectangular cross section aluminium pipes and to test the performance of the PVT collector with several laminar flow rates. Experiments with the same laminar flows show the same behavior than in the numerical results.

Keywords: linear concentration, active cooling, PVT.

1. Introduction

Within the field of solar collectors, there is a group of hybrid photovoltaic/thermal (PVT) generators, which simultaneously convert sunlight into electrical and thermal energy. Electrical energy is produced by photovoltaic cells. Thermal energy is produced by means of a circulation of fluid around the hottest parts of the system (namely the photovoltaic cells). Due the difference in temperatures, heat is transferred to the fluid providing an energy source whilst cooling the cells.

PVT systems can operate under concentrated or un-concentrated light. The system analysed in this research, will operate under linear concentrated radiation.

These PV/T systems have an inherent contradiction: from the point of view of the electricity generation, the temperature of the PV cells must be kept as low as possible, which leads to low outlet temperatures of the thermal fluid, by contrast, from the thermal energy point of view high outlet temperatures are needed. Hence, a balance between PV efficiency and thermal energy production must be chosen.