Efficacy of absorber-plateless PV/T system: With low-cost and energy-efficient plastic capillary exchanger

The high cost of the metal heat exchangers employed in traditional photovoltaic/thermal (PV/T) solar systems has hindered the widespread adoption of this technology in buildings. To address this, a low-cost and efficient PV/T system utilizing plastic capillary mats as the heat recovery exchanger (PV/T-CHE), without an absorber plate, is proposed and established in this study. The thermal and electrical performances of the newly designed PV/T system are evaluated under various operating scenarios with hot water temperatures ranging from 30 °C to 50 °C. A comparison of the levelized cost of heat (LCoH) for the proposed PV/T-CHE and two traditional PV/T systems with metal heat exchangers is presented. The results show that the proposed PV/T can effectively produce hot water, achieving thermal efficiencies of 33.4 %, 28.1 %, and 26.4 % at heat recovery temperatures of 30 °C, 45 °C, and 50 °C, respectively. The corresponding overall efficiencies are 52.8 %, 46.9 %, and 45.1 %, respectively. These results demonstrate that heat recovery enhances the electrical efficiency by approximately 2.7 % compared with that of standard PV. The LCoH of the PV/T system is estimated to be between 0.010 and 0.013 USD/kWh, which is significantly lower than that of a PV/T system with metal heat exchangers. This novel cost-effective design simplifies installation, making the exchanger suitable for both new and retrofitted PV/T systems, with strong potential for large-scale applications to meet hot water and electricity needs in buildings.