Instead of turning up the thermostat up this winter, why not just throw on some nanowire-coated clothing to stay toasty?
According to the International Energy Agency, indoor heating accounts for almost half of total global energy usage, mainly on heating residential buildings. In a recent study published in Nano Letters, researchers from Stanford University describe a better way to conserve thermal energy. The nanomaterial-coated fabric they created traps heat inside a person's clothing, thereby removing the necessity to heat empty space and inanimate objects, and lowering the cost of household heating to (theoretically) almost nothing.
The team began the research by looking for a wearable way to keep infrared radiation in the body. “Let's say you want to make your clothes reflect heat, you need metal,” says Yi Cui, the lead scientist on the study. “But you're not going to put metal on your body.”
Instead of using rigid metal, the team decided to create a coating using easily bendable silver nanowires that can go on top of everyday clothing. The coating works two ways to heat up the body. For everyday wear, cloth coated with silver nanowires successfully reflects infrared radiation—something humans naturally emit—back into the body. To warm up even more, a person wearing the cloth can give it a charge while sitting at the computer. The movement of electricity from an electrical device across the cloth creates Joules heating, or heat generated while crossing a current.
The cloth is breathable enough to allow sweat to pass through it, keeping the wearer comfortable. It's relatively cheap to use, too: Cui says it only costs about $1 for enough silver to cover all clothing for the whole body (minus the head and hands, of course). And the best part? Wearing the coated cloth could save the average person up to $200 per year on heating costs.
Cui says the amount of energy saved by a person wearing nanowire-coated material for a year would be enough to power 1,000 light bulbs for 10 hours.
The nanowire-coated cloth is not yet commercially available, and probably won't be for a few years. (Silver nanowire still needs further testing to determine whether it has human health impacts.) In the meantime, the Stanford team plans to start developing a similar wearable coating to cool down the body. That way, the energy needed to heat and cool buildings could both be cut down year round.