A research team from Nanyang Technological University applied insulation coatings to designated building paints in an industrial area in western Singapore, and collected environmental data such as air flow, surface and air temperature, humidity, and radiation to understand the effect of insulation coatings on reducing urban heat. (Provided by Nanyang University of Technology)
Global warming has led to increasingly hot weather, making it urgent to cool the environment. One way is to paint insulation coatings on building surfaces to reflect sunlight heat. Local research shows that this method can reduce the perceived temperature of pedestrians on urban streets by 1.5 degrees Celsius, and lower the temperature inside buildings, thereby reducing the use of air conditioning and saving energy and electricity.
High rise buildings and busy streets in the city are all high energy storage bodies that continuously emit a large amount of heat. In addition, urban design often lacks green space, which leads to the Urban Heat Island Effect.
Especially in the streets between two buildings, also known as “street canyons”, not only is the heat high, but the buildings on both sides are also windproof, preventing air circulation and making the “canyon” even more stuffy and hot.
One of the recognized feasible solutions to alleviate the urban heat island effect is to apply thermal insulation paint on the surfaces of buildings and streets. This coating contains additives that can reflect solar heat, helping to reduce the heat absorbed and dissipated by various surfaces.
A research team from Nanyang Technological University applied insulation coatings to designated building paints in an industrial area in western Singapore, and collected environmental data such as air flow, surface and air temperature, humidity, and radiation to understand the effect of insulation coatings on reducing urban heat.
Research has found that if the top surface of a building is not coated with insulation paint, the temperature can rise to 73.2 degrees Celsius, the road surface can reach 53.1 degrees Celsius, and the wall surface can reach 34.5 degrees Celsius.
After applying insulation coatings on different surfaces, the reflection of solar heat energy is greater, resulting in a lower absorption of heat energy on the surface. The peak sensible heat of the top surface, pavement, and walls of the building decreased by about 40%, 23%, and 5% in the afternoon, respectively; The highest temperatures on these surfaces have also decreased, reaching 48.7 degrees Celsius, 44 degrees Celsius, and 28.7 degrees Celsius, respectively.
Overall, buildings painted with thermal insulation coatings emit a 30% reduction in heat, which can also lower the temperature around the building by up to 2 degrees Celsius. Pedestrians can also feel a decrease of about 1.5 degrees Celsius in the ambient temperature on the streets.
Associate Professor Wen Wenbin from the School of Mechanical and Aerospace Engineering at Nanjing University is one of the members of the aforementioned research team. In an interview with the Lianhe Zaobao, he said that the insulation coating market in Singapore is not yet mature, and the price of insulation coating here may be higher than that of ordinary coatings.
“However, in more mature markets such as the United States, the price of thermal insulation coatings and general coatings is almost similar.” Specific additives are required to make the insulation coating, but if the insulation coating is produced on a large scale, the difference between manufacturing costs and ordinary coatings is negligible.”
To alleviate the urban heat island effect, the heat insulation paint can play two roles, one is to reflect the solar heat energy, and the other is to exhaust the heat.
Wen Wenbin said: “The team is developing a new generation of paint with better heat removal function, because although the thermal insulation coating can reflect the sun’s heat and make the building surface absorb less solar energy, it cannot be 100%, and the building surface will still absorb some heat energy.” So the key is how efficiently the surfaces can cool themselves after absorbing heat.”
