Foam insulation that expands and contracts ‘could save 40% of cooling energy’

A ‘programmable’ insulation foam that expands in hot weather and contracts when temperatures drop could cut the energy used to cool homes by 40%, according to its creators.

Developed by researchers at the Fraunhofer Cluster of Excellence Programmable Materials in Freiburg, Germany, the foam is aimed at enabling widespread reductions in energy consumption.

Air conditioning devices “devour a lot of energy”, the researchers said, contributing to carbon dioxide emissions and climate change. They hope that programmable home insulation could replace air conditioning systems in future.

“There is huge potential here – up to 40% of the cooling energy can be saved in this way,” said researcher Dr Susanne Lehmann-Brauns.

The programmable insulation is based on a foam that changes shape depending on the temperature – at high temperatures its pores open and the material expands, but when it cools the pores close and it contracts. Unlike conventional shape memory foams, the researchers said the process is reversible and can happen “over and over again”.

Used in a house, the foam elements could expand during the heat of the day to seal ventilation gaps between the walls and their cladding, preventing hot air from entering. At night, it would contract and open the ventilation gaps, allowing fresh air to circulate and cool the building.

The programmable material could also enable high heat transport capabilities in heat pipe applications, the researchers said, or programmable heat storage.

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