Influence of retro-reflective and high-reflective coatings on thermal performance of buildings in summer and winter: A contrast experiment

The solar radiation has a great effect on the thermal environment of regional buildings, and reflective coatings can increase the amount of solar reflectance and reduce the solar heat gain. In summer, it can effectively improve the regional thermal environment, but in winter, it may be ineffective, or even counterproductive. This study aimed to experimentally evaluate the thermal performance of retro-reflective coatings (RRC) with unique reflective mechanism in enclosed buildings in both summer and winter, and took high-reflective coatings (HRC) as the comparison. The regional albedos, wall temperatures, and air temperatures were measured, which showed that both in summer and winter, RRC had higher regional albedos, lower wall temperatures and air temperatures than HRC, however, the differences were smaller in winter, which would lead to more thermal benefits in summer caused by RRC than thermal penalties in winter. For the regional albedos, the maximum differences in summer and winter were 4.99% and 2.46%, and the values were 2.74 °C–11.61 °C and 1.39 °C–5.61 °C for the wall temperatures, 2.10 °C and 0.39 °C for the air temperatures in the enclosed space.