current trends in cool coating technology

Global warming can increase urban temperatures by up to 10 °c, with significant health, environmental and energy implications. the materials of the building and urban fabric have an impact on the thermal balance of the city and significantly increase the risk of urban warming. this review describes advances in the design, manufacture and application of ultra-low and low surface temperature coatings for buildings and equipment. it covers the definitions, mechanisms, evaluations, and recent technological advances of natural, light-colored, infrared solar reflective, pcm-doped, thermochromic, quantum dot, and plasmonic cool materials. a comparative analysis of the experimental results on the cooling capacity and thermal performance of the traditional or new materials is provided. it is shown that natural cool coatings can reflect 80-90 % of solar energy and save 18 % of cooling energy, white and colored cool pigments can exhibit 85-95 % solar reflectance, and novel cool materials can reflect more than 93 % of solar thermal energy. in addition, pcm-doped cool coatings can reduce the surface temperature by 2.5 to 19.7 °c. the aim is to present the best method among those proposed in terms of energy and raw material cost for cool coatings. this review also explains how cool coatings with high solar reflectance can absorb less solar energy and increase the lifetime and efficiency of power systems and electronic devices that are typically exposed to sunlight.