Scientists from the University of Nanian Technology (Singapore) have developed an unusual white paint that helps to cool buildings – even in hot and humid climate – without using air conditioning and energy. This coating reflects the sun's rays, radiating heat and sweating, – slowly evaporates water, like a skin, reduces the heat of the surface. The results were published in the magazine Science.
The main advantage is passive cooling, he explains Lee Hong's documents. It works without electricity and efficiency even in wet climates, where other cooling methods are ineffective.
What is the difference with the usual color?
Commercial “cooling” paint usually only operates due to radiation cooling: they reflect sunlight and radiate heat into the atmosphere. However, in places with high humidity, for example, in Singapore, the steam holds heat on the surface, which makes this approach less used.
In addition, conventional cooling paints often lose efficiency over time: under the sun and rain, white fade and the coating begins to reflect the worse light.
The development of Singapore scientists combines three cooling strategies:
- Solar reflexes – maximum 92% of sunlight are reflected;
- Radiation cooling – up to 95% heat is emitted in the form of infrared radiation;
- Evaporation cooling – due to the surface “sweating” gradually evaporates moisture.
This becomes possible thanks to the porous structure of the cement platform and nanoparticles increases reflexes. Also added to paint polymers and salt to preserve moisture and prevent cracking.
Scientists cover three identical buildings with different colors:
- Normal white,
- Trade cooling,
- And your new.
Two years of influence of the sun and rain, only their paint is still white and retains cooling properties. Moreover, the building with new paint consumes less than 30% 40% for air conditioning compared to other buildings.
Effective for cities and climate
The coating can also fight the effects of the enthusiastic island of the city (UHI) – a phenomenon in which the dense development makes the cities much hotter than the surrounding areas. Unlike the air conditioners throwing heat into the air, the paint radiates it up, into the atmosphere, in the form of invisible infrared radiation.
About 60% of all energy in cooled buildings, he said that the company of the Wi Wi study. Our paint can help reduce this energy consumption and make the cities cooler.
The team hopes that the development will be widely used, especially in hot megacities. Indeed, in addition to energy efficiency, new paint is durable, inexpensive in production and can operate in conditions other colors are helpless.