Large public buildings, commercial complexes, and business office buildings have large volumes and roof areas. Metal roofs and domes are exposed to long-term direct sunlight, causing severe overall heat accumulation, which leads to long-term high-load operation of central air-conditioning and persistently high energy consumption. The electricity-free cooling coating suits large building facades and roofs, passively reduces overall building heat gain, optimizes indoor comfort temperature, and significantly reduces building cooling energy consumption.