Working in an office building can be a temperature roller coaster, with the dictatorship of air-conditioning systems seeming able to keep people too hot and cold simultaneously. Funded by ARPA-E – the research arm of the US Department of Energy are attempting to develop clothes that can change their thermal properties to adapt to the environment and wearer’s body.The clothing can control heat by changing how much radiation it allows to escape the body or how easily air can circulate. Alon Gorodetsky’s team at the University of California, Irvine, is aiming to control radiative heat. “We’re drawing inspiration from squid, from cephalopods, that can do these amazing camouflage displays,” he says.
Squid can modify how they reflect visible wavelengths of light, using a cocktail of proteins in their skin. The team is adapting the technique to longer, infrared wavelengths that carry heat. “We are leveraging that for materials that can regulate the thermal emissions of an object,” saysGorodetsky.
Jintu Fan’s team at Cornell University in Ithaca, New York, is taking a different approach by controlling the circulation of warm and cold air through a network of miniscule tubes embedded in an undershirt. “On top, you can wear whatever you want to,” says Fan. Temperature sensors in the vest monitor the skin, pumping in warm or cool air as required. “It’s like a mini air-conditioning system, but next to your body,” says Fan. This aims to make people comfortable in a wide range of external temperatures.
Based in Menlo Park, California, Roy Kornbluh and his colleagues at non-profit research company SRI International are building prototype shoes that incorporate a heat pump made from a kind of plastic which is very good at transferring heat. This allows them to pull heat out of the body through the sole of the foot when it’s hot, and to push heat in when it’s cold, and are focusing on the body’s glabrous, or hairless, areas. In mammals, these areas act like a car radiator, helping heat escape from the body.
Up to now, clothing that can control heating, has only appeared in bulky or uncomfortable garments for the military, aerospace and emergency services, or in lab experiments. ARPA-E has invested $30 million to make systems that are comfortable to wear in everyday life.
Keeping office temperatures within a tight range creates a big demand on resources, with air-conditioning systems accounting for 13 per cent of energy used in the US. “If you can expand that temperature band by a couple of degrees in each direction and people wear clothing that controls comfort on the individual, you can save 1 or 2 per cent of all energy in the US,” saysGorodetsky. “That’s a huge number. Even a tiny fraction of that would be huge.”
“ARPA-E wants to reduce energy usage in the US – that only works if a lot of people are wearing these,” says Kornbluh. “We want everyone to be able to wear these, just like you have a smartphone with you.”