Climate change: Low cost, low energy cooling system shows promise

By Matt McGrath, Environment correspondent

BBC News: 26 October 2018

Low_Energy_Cooling_System — The roof array that can cool a house with little energy use

Researchers in the US have scaled up a new low-cost system that could provide efficient cooling for homes while using very little electricity.

The team has developed a roof-top sized array, built from a highly reflective material made from glass and polymers.

In tests, the system kept water around 10C cooler than the ambient air when exposed to midday sunlight in summer.

The approach could also be scaled up to cool power stations and data centres.

The system is based around what’s termed a cooling meta-material, which is essentially an engineered film not found in nature.

Last year, researchers at CU Boulder in the US published research on the extraordinary properties of the new film, which reflects back almost all incoming light from the Sun.

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But it also has another cooling trick that makes it quite special. If you use the film to cover water, it allows any heat in the liquid to escape into the air.

So when the heat escapes and is not replaced because the material deflects away sunlight, temperatures drop rapidly.

Now the scientists have improved the system and and built and tested a 13-sq-metre array of panels, that’s small enough to fit on most rooftops.

“You could place these panels on the roof of a single-family home and satisfy its cooling requirements,” said Dongliang Zhao, lead author of the study from CU Boulder’s Department of Mechanical Engineering.