“Why do you need to cool and heat the whole building? Why don’t you cool and heat individual people?” asked Yi Cui, professor of materials science and engineering at Stanford University.
Putting on or taking off articles of clothing works to keep a body cool or warm within a certain temperature range; outside that range we rely on heating systems and A/C to keep us comfortable. But what if one garment did both the heating and the cooling?
Cui’s colleague and postdoctoral fellow Po-Chun Hsu decided to create a fabric that could control radiation in both directions. He used two materials with different properties—copper and a carbon coating—and sandwiched them between two layers of polyethylene. When the copper faces out, it keeps heat in and warms the wearer. With the carbon layer facing out, heat is released and a body is cooled.
The material can expand a person’s range of comfort by over 10 degrees F. DOE recommends that we keep thermostats between 68 degrees F in the winter—cooler at night—and 78 degrees F in the summer. That’s a range of 10 degrees F of comfort. Add 10 degrees F to that and that’s quite a comfort range. But Hsu predicts that the potential comfort range increase is close to 25 degrees F.
The material is not yet ready to wear. It will become a woven fabric that is reversible and can also be laundered. Look for it in your nearest GAP store in a few years?
For more on the Stanford research, click here.