Surface Reflectance Change can Induce Reduction in the Surrounding Ambient Environment Warming

Abstract

Global warming has emerged as a major issue of concern as the fallout would have a wide-spread impact on many climate processes in addition to posing a serious threat for human development, directly or in-directly. COP21 at the Paris agreement settled to limit global warming well below 2°C in the future. This goal can be attained by ensuring a drastic reduction in the emission of greenhouse gases or by cutting down the use of energy consumption, an obvious solution but difficult to implement. A more acceptable and easy approach would be to reduce the use of energy to cool buildings and surfaces by adopting simple scientific techniques. The present work explores the feasibility of one such approach, which can be applied in large cities and urban regions; knowing that by increasing the surface reflectance (albedo) for incoming solar short wave (SSW) radiation it is possible to decrease the temperature of the surface. If the appropriated surface area is large enough then it is possible to cause a decrease in the ambient air temperature. Three different types of heat-resistant Superseal Thermoflex P-111 coatings of different colours were applied on the roof surface to evaluate their respective reflectance properties towards the incoming SSW radiation incident on the roof with reference to the resulting surface temperature. The average reflectance in the spectral range 280-880 nm – for dark pink, light pink and white colour coats – were estimated as 0.44, 0.61 and 0.76, respectively; the obtained values were significantly larger than that observed for asphalt/cement coated surfaces. The higher reflectance of white coating leads to less heat absorption by the roof surface open to the SSW radiation and thus a significant drop in the surface temperature. Also, the heat transmitted underneath the surface space will be much reduced, even the emission (loss) of radiation (Infra-Red) from such a surface into the surrounding environment will be reduced.