Solar energy optimization for energy-efficient poultry farming: A multi-climate simulation approach

Increasing energy costs and environmental concerns drive the poultry industry toward sustainable solar solutions. A hybrid photovoltaic-thermal (PVT) system, combining flat-plate collectors and polycrystalline PV panels, was optimized for heating and cooling a 1000-laying-hen house in three Iranian climates (Shahrekord, cold mountainous; Kerman, hot-dry; Rasht, humid temperate), maintaining indoor temperatures of 20–24°C. System modeling utilized climatic data and response surface methodology (RSM) for optimizing tilt angle. Annual optimal tilt angles were: Shahrekord (PV panels 47°, collectors 32.8°), Kerman (PV panels 45°, collectors 33.24°), Rasht (PV panels 52°, collectors 38.57°). Average solar fractions reached 40.4% in Kerman (peaking at up to 100% in October), 39.5% in Shahrekord (peaking at up to 100% in September), and 25.7% in Rasht (with a maximum of 58% in May). Economic analysis under three price scenarios (fixed, annual increase, step-up) showed NPV ranges of $967–1767 and IRR 17.9%–21.4% in Kerman (highly feasible), $334–983 and IRR 13.0%–16.7% in Shahrekord (feasible), and negative NPV (−$560 to −$129) with IRR 5.4%–9.4% in Rasht (infeasible). The PVT system proves economically viable and sustainable in sunny/dry regions, offering resilience to energy price volatility.