At first glance it sounds like a contradiction, but this is the effect actually achieved by the innovative coating Solcold developed by an Israel-based startup.
The cooling coating employs an active cooling process involving the basic principles of laser cooling, applying the idea to the spectrum of sunlight. The coating not only reflect the sunlight, lowering the temperature of exposed surfaces and rooftops, decreasing energy consumption of conditioning systems. The solution employs the sun rays to activate a chemical process able to transform façades and rooftops in a sort of layer of ice, actively cooling them up to 10° C.
The researchers engineered a coating that resulted in a two-layered paint, an outer element that filters out some of the sun’s rays, and an inner one that converts heat to light, resulting in coolness below the ambient temperature. Lowering the building’s emissions footprint, the solution could be easily employed in new constructions as well as in order to improve energy efficiency of existing ones.
The coating could then also be used in space, to ward off heat resulting from the lack of air. Actually, to disperse heat away from space equipments are used reflecting fabrics and heat exchangers.