Experimental and 4E (energy–exergy–economic–environmental) assessment of an air-based PV/T collector with nonwoven fabric absorber

Conventional photovoltaic/thermal (PV/T) systems are constrained by decoupled design approaches that treat absorber geometry, airflow dynamics, and PV configuration independently, leaving the governing thermo-fluid interactions unresolved and limiting heat extraction and electrical stability in compact systems. This study establishes, for the first time, a coupled flow-structure-PV interaction framework that experimentally quantifies how porous absorber morphology, airflow acceleration, and PV packing density jointly govern energy-exergy-economic-environmental performance. A novel hybrid air-based PV/T collector is developed by integrating monocrystalline mini photovoltaic modules with a diagonally tensioned nonwoven polyester fabric absorber, enabling simultaneous electrical and thermal conversion through a lightweight porous structure. Three modular configurations (PV6, PV12, and PV20) were tested under real outdoor conditions in Muğla, Türkiye, using both natural and forced convection. The developed system achieved daily mean electrical efficiencies of 6.67%, 7.04%, and 4.25%, and daily mean thermal efficiencies of 32.4%, 32.3%, and 38.4% for PV6, PV12, and PV20, respectively. Active airflow increased electrical power by 25-45% in compact arrays and thermal output by up to 257% in larger modules, while reducing surface temperature by as much as 52.6 °C. Exergy analysis indicated a 26-44% improvement in electrical exergy for compact systems and a 29% rise in thermal exergy for PV20, confirming strong convective-radiative coupling. The techno-economic evaluation yielded payback periods below 0.6 years and annual CO2 mitigation up to 0.10 ton/year m2. The proposed configuration establishes a new pathway by experimentally revealing the coupled interaction between porous absorber morphology, airflow acceleration, and PV packing density, providing a physically grounded mechanism for performance enhancement beyond conventional textile-based PV/T designs.