Modeling and empirical study of TiO2/water nanofluid flows in a modified configuration with new layer arrangement of a photovoltaic/thermal system

Application of nanofluids and modification of the geometric configuration have significant impacts on the behavior of photovoltaic/thermal systems. In the current research, a modified model of layer arrangement for a conventional PV/T panel is presented. A remarkable part of the thermal resistances in the energy transfer path from the collector glass surface to the coolant was eliminated by removing the Tedlar from the system. Half-pipe structure instead of conventional pipe used in the cooling section. Different concentrations of TiO2/water nanofluid were used as the coolant in the system. The role of diverse variables such as radiation intensity, inlet coolant temperature, and wind speed on the performance of the proposed panel are studied. A reasonable understanding between the modeling and the experimental outputs is observed. According to the proposed model results, the temperature difference between the different parts of the system, i.e., glass, cells, and metal plate, and the average temperature of the coolant decreases to less than 4%. By application of TiO2/water nanofluid in this new configuration of PV/T system, the thermal efficiency increases dramatically. Based on the empirical outputs, the thermal efficacy of the system with 0.5 wt% nanofluid, changes from 42.8 to 69.7% during a day.