An Experimental and Numerical Study on the Optimum Flow Rate of a Photovoltaic Thermal System Integrated with Phase Change Materials

Photovoltaic thermal (PVT) systems can be defined as solar cogeneration systems, which generate both electrical and thermal energy by means of a single panel. Within the scope of Nearly Zero Energy Buildings (nZEBs), PVT systems based on phase change materials (PCMs) have a remarkable potential in meeting the electrical and thermal energy demand for both facade and roof applications in buildings. In PVT systems, phase change materials (PCMs) could be used to provide thermal energy after the sunset and to manage the heat load on the PV. In the present study, a PCM-based PVT system was modeled, established, and tested under real meteorological conditions. Experimental results for the ambient, inlet, and outlet temperatures and solar radiation are presented. The temperature distribution of the system was analyzed. The system was modeled in ANSYS FLUENT. The model was validated with application of experimental data. The determination coefficient between the modeled and experimental outlet temperatures was found to be 0.9444. The optimum flow rate was investigated for the system. The maximum outlet temperature was achieved at a flow rate of 19 l/h. The conclusion was that flow rates of 15–21 l/h can be used in studies as an ideal flow rate for a PVT-PCM system with paraffin.