Experimental and numerical study of a PV/Thermal collector equipped with a PV-assisted air circulation system: Configuration suitable for building integration

Abstract

In this paper, the energy performance of a photovoltaic/thermal collector equipped with a direct PV air circulation device is studied experimentally and numerically. In this system, the air circulation through the collector duct is ensured by a low input power DC fan that is directly connected to a PV module of small power capacity. In fact, depending on which period of the year the PV/thermal collector is being employed, a 4 Wp or 12 Wp PV panel is used to supply the electrical power to run the DC fan respectively for cold/winter or hot/summer periods. Therefore, the air flow rate under which the present hybrid collector operates is variable and highly affected by the incident solar radiation intensity. A theoretical model for the present hybrid system, in which air flow rate is introduced as a simple empirical correlation relating flow rate to solar radiation, was developed and obtained numerical results have been validated by experimental ones. Simulation and experimental results have been found in reasonably good agreement in terms of PV cell temperature, outlet air temperature, and electric PV peak power. Moreover, the obtained results revealed that low flow rate PV-assisted air circulation systems, if properly sized, would be very attractive for cold periods and winter conditions because of the high air temperature difference they could produce which is a key parameter for space heating applications. On the other hand, the high flow rate system seems to be very suitable for summer conditions where priority is given for the ventilation of PV modules to lower their cells temperature. The suggested PV/T collector design offers the advantage to be self-energy dependent and seems to have a great potential in remote areas.