Experimental and numerical evaluation of PVT performance with V-trough reflectors and cooling tubes equipped with twisted tapes

Abstract

The irradiance received by photovoltaic/thermal (PV/T) systems can be insufficient during certain seasons, decreasing the performance and cost-effectiveness of the thermal system. Concentrated PV/T systems address this issue by boosting both electrical and thermal output power, but this enhancement leads to greater PV temperatures, necessitating an advanced cooling solution. This study is the first to experimentally evaluate the impact of integrating twisted tapes (with twist ratios of 3, 4, and 5) into a flat plate collector on the electrical and thermal performance of a low-concentrated PV/T. Experiments were conducted with inlet flow rates ranging from 25 to 150 Lit/h under concentration ratios (CR) of 1.5, 2, and 2.5. The experimental results were verified through simulations conducted in ANSYS FLUENT for both scenarios—one including the collector and one without it. Results demonstrated that employing a solar concentrator with a CR of 2 and a thermal collector with twisted tapes (twist ratio of 3) at a flow rate of 150 Lit/h could increase average electrical power from 59.2 W to 67.5 W (14 % rise), and recover 197.2 W of thermal power. An economic analysis revealed that the levelized cost of energy (LCOE) index for PV/T systems, both with and without solar concentration, is higher than that for a plain PV, indicating that this system is cost-effective when its thermal energy is also utilized. Additionally, integrating a thermal collector with twisted tapes into a PV system with a nominal power of 1 kW and a solar concentrator (CR = 2) enhances net CO₂ mitigation over the module’s 25-year lifespan from 60 tons to 139.1 tons (131 % increase) and 156.9 tons (161 % increase), respectively.