Most of the advantages of electric cars are about efficiency. But in the winter, it’s the very inefficiency of your petrol-powered engine block that keeps your keister from freezing, since waste heat from the combustion process is what makes it through your heating system. On a January morning, your electric vehicle has to divert battery-stored energy through heating elements to keep you warm, and that’s power that isn’t driving the wheels. By some estimates, keeping your EV toasty warm can cut its range by 30 percent.
But some scientists are trying to tackle that problem. A trio at Massachusetts Institute of Technology claims to have developed a thin, transparent film that can store solar energy when the sun is shining, and release it as heat on command. That means that you can use this afternoon’s sunshine to defrost tomorrow morning’s windscreen.
According to an MIT statement, the polymer film contains special molecules that are stable in two different states. Solar radiation kicks these molecules into a high-energy “charged” state, thereby storing energy chemically — where it’s stable — rather than thermally, where it would radiate away. When we want that energy back, a small jolt of electricity or heat knocks the molecules back down to their original state, and they release all that stored energy as heat.
The most obvious use, say the researchers, is in automobile window de-icing, where the polymer could be sandwiched between two pieces of glass right along with the safety film — an application that BMW, a sponsor of the project, is particularly interested in. But the polymer may be versatile enough to be used to heat seats and steering wheels, or even let you solar charge your socks before a motorcycle ride, turning on the heat right before you lose feeling in your toes.
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