US researchers have developed a self-powered smart window that can cut building HVAC costs by up to 40 per cent by augmenting window tint – blocking light and infrared heat.
Electrochromic glass typically needs a separate power source for operation, making it complicated to retrofit into existing buildings, but researchers from Princeton University have come up with an all-in-one solution to make it cheaper and easier to install.
They’ve applied a new solar cell technology to the windows that selectively absorbs near-ultraviolet light – making it transparent – and providing the energy needed to adjust the window’s tint and block out light and infrared heat.
“This new technology is actually smart management of the entire spectrum of sunlight,” Andlinger Center for Energy and the Environment engineering professor Yueh-Lin Loo said.
The charge generated from the solar triggers a reaction in the electrochromic window, turning it from clear to dark blue, which can block more than 80 per cent of light.
“Using near-UV light to power these windows means that the solar cells can be transparent and occupy the same footprint of the window without competing for the same spectral range or imposing aesthetic and design constraints,” Dr Loo said.
“Typical solar cells made of silicon are black because they absorb all visible light and some infrared heat – so those would be unsuitable for this application.”
Princeton doctoral student Nicholas Davy said the team was working on creating a flexible version of the technology that could be applied to existing windows as a laminate, which could be controlled wirelessly using an app.
“Someone in their house or apartment could take these wireless smart window laminates – which could have a sticky backing that is peeled off – and install them on the interior of their windows,” Mr Davy said.
“Then you could control the sunlight passing into your home using an app on your phone, thereby instantly improving energy efficiency, comfort and privacy.”
The Princeton researchers are so sure of the commercial potential of their technology that they’ve started a new company, Andluca Technologies, to further the work and look into a range of applications for the transparent solar cells, including powering Internet-of-Things devices and low-powered consumer devices.
“It does not generate enough power for a car, but it can provide auxiliary power for smaller devices, for example, a fan to cool the car while it’s parked in the hot sun,” Dr Loo said.
The research has been published in .