An Experimental Analysis of Photothermal Nanocoatings for Greenhouse Energy Efficiency

Greenhouses require intensive energy input to maintain stable growing conditions, particularly in extreme climates. In prior research, we proposed a greenhouse covering coated with antimony tin oxide (ATO) nanoparticles and demonstrated through simulation that such coatings could significantly reduce energy demand without reducing photosynthetically active radiation (PAR). The present study experimentally validates those predictions using a controlled lab-scale greenhouse prototype. Polyethylene sheets were coated with ATO nanoparticles to form a spectrally selective photothermal nanocoating and integrated into the greenhouse prototype. The prototype was tested inside a thermal chamber equipped with a full-spectrum solar simulator, enabling replication of seasonal extremes. Two representative dates, December 19th (cold conditions) and July 21st (hot conditions), were selected to represent worst-case seasonal performance. The thermal and energy responses of the greenhouse with ATO-coated sheets were compared with those of an identical greenhouse without coatings with a standard uncoated double-layer polyethylene covering. The experimental findings confirm strong alignment with earlier simulation studies, demonstrating both the accuracy of the simulation models and the practical feasibility of the coating. Energy testing revealed that ATO nanocoating improved total annual energy savings over 10% compared to uncoated double-layer polyethylene films. Notably, these efficiency gains were achieved without reducing PAR transmittance, ensuring no negative impacts on crop growth. This study provides the first experimental validation of nanocoated greenhouse films for energy management, confirming their dual role in reducing operational energy use while sustaining plant productivity. This study advances sustainable agricultural practices by demonstrating the potential of photothermal nanocoatings as scalable, high-impact solutions for greenhouse energy efficiency.