Bio-inspired passive cooling of photovoltaic modules using Sphagnum palustre moss: An experimental study

This study investigates the potential of Sphagnum palustre moss as a completely natural, passive evaporative cooling medium for photovoltaic (PV) modules. Unlike synthetic hydrogels or complex biomimetic structures, the proposed system utilises the innate porous structure and high water-retention capacity (up to 20 times its dry weight) of natural moss to facilitate rapid heat dissipation. Experimental evaluations conducted under effective solar irradiances of 510.4–820.9 W/m2 demonstrate that the moss-cooled configuration achieves a remarkable temperature reduction of 27.4–39.8 °C compared to uncooled standalone panels. These thermal improvements translate into relative power gains of 6.10% to 11.66% and an exceptional evaporative cooling power of up to 598 W/m2. The results establish Sphagnum palustre as a highly effective, biodegradable, and low-cost alternative for PV thermal management, offering performance competitive with advanced engineered cooling materials whilst ensuring long-term environmental sustainability.