Energy, economic, and environmental analysis of converging air-based photovoltaic-thermal (air/PV-T) systems: A yearly benchmarking

Abstract

Two converging channel configurations of photovoltaic-thermal (PV-T) systems, i.e., inlet and outlet at different sides (Case 1) and the inlet at the middle and outlets at the sides (Case 2), are investigated numerically. The results reveal that Case 1 features a nearly uniform and lower temperature distribution (up to 7 °C) for practical air flows, and the appropriate convergence ratio is 2:1 (inlet to outlet channel height) for which the PV surface temperature is lower by 8 °C than that of a similar conventional collector. Meanwhile, energy analyses based on the so called ‘rate of extra energy gain per PV surface area, E˙Ac (W/m2)’ show that the air mass-flow rate has an optimal limit of ∼0.1 kg/m2. s for a typical conventional power plant conversion factor (PPCf) of 0.3–0.4. At this limit, up to 500 W extra power per unit area of PV module can be gained by changing a PV to its proposed counterpart PV-T system reducing the levelized cost of energy (LCOE) by an order of magnitude for the PV-T (0.02–0.054 $/kWh) compared to a standalone PV (0.037–0.146 $/kWh). Such PV-Ts show 10% and 150% net CO2 mitigation in comparison to the conventional PV-Ts and the corresponding standalone PVs.