Have you ever found yourself lying on the couch when the sun changes angle, and suddenly it becomes unbearably hot when before you were just nice and cozy? Imagine being your house, which can’t just get up and move. Controlling indoor temperatures often requires action like closing curtains to cut out bright light, turning up the air conditioning or a fan, opening or closing doors, or taking other steps to keep the indoor climate comfortable.
Many of the measures used to keep indoor temperatures stable, unfortunately, require energy, especially in big office buildings. Researchers, architects, and materials scientists are hard at work on a variety of techniques and options for helping buildings regulate their own temperatures without having to resort to using energy: for example, highly efficient glass for windows limits heat exchange to keep buildings cool in summer and warm in winter.
UC Berkeley scientists have come up with another cool innovation: self-closing curtains.
They’ve developed a special textile made out of carbon nanotubes, which respond to light by converting it into heat. The heat transfers to a plastic membrane at the back of the nanotube, forcing the backing to expand, while the nanotubes don’t expand with it. Consequently, the fabric opens up, effectively closing the curtain in response to light. When the light fades, the plastic backing shrinks again because it’s not being heated anymore, and the curtain opens.
Thanks to the sensitivity of the nanotubes and the backing, they react to even low levels of light.
This technology has some tremendous applications for keeping building temperatures within a set range. For starters, no human interaction with the curtains is needed to open and close them, which reduces the risk that a forgetful human (or an unexpected holiday or other event) will drop the ball on keeping the building cool. Additionally, no added technology, like sensors or a fancy automated system, is required: this saves energy and keeps the curtains very simple, so they’re easy to work with and maintain. No electrician needed to set these curtains up!
The curtains are also highly reactive and very sensitive, making them ideal for handling temperature control in a range of environments. Whether a building is enduring the brutal heat of the Phoenix desert or the glare of snowy days in New York City, these curtains could help regulate the internal temperature and save significant amounts of energy, which is good news for building maintenance costs.
Researchers involved with the project believe the curtains could save on air conditioning by as much as 50% in a year, a significant feat in terms of finances and the environment. While they aren’t available for general distribution yet, there’s a chance that someday, not too far in the future, you could be hiring a handyman to install a set of self-regulating curtains of your own in your home.