Grain reserve warehouses mostly have metal or concrete roof and side-wall structures, which absorb and store heat severely under summer sunlight; heat continuously penetrates into the warehouse through the roof and side walls, keeping indoor temperatures high. As the side walls heat up, grain in contact with them can also deteriorate from the rising temperature, affecting storage quality. Meanwhile, ventilation and dehumidification equipment must run at high load for long periods, resulting in high energy costs. Coating with the electricity-free cooling coating effectively lowers the temperature of the warehouse roof and side walls, reduces inward heat conduction, assists constant-temperature grain storage, and reduces O&M energy consumption.