By applying a new solar cell technology, researchers have developed a self-powered version of smart windows that could help save energy costs.
Smart windows with controllable glazing can augment lighting, cooling and heating systems by varying their tint, saving up to 40 percent of an average building's energy costs.
Conventional smart windows require power for operation, and therefore are relatively complicated to install in existing buildings.
The new self-powered version promises to be inexpensive and easy to apply to existing windows, researchers said. This system features solar cells that selectively absorb near-ultraviolet (near-UV) light, so the new windows are completely self-powered. Yueh-Lin (Lynn) Loo, Professor at Princeton University, New Jersey, US, said,
Sunlight is a mixture of electromagnetic radiation made up of near-UV rays, visible light, and infrared energy, or heat. We wanted the smart window to dynamically control the amount of natural light and heat that can come inside, saving on energy cost and making the space more comfortable.
The smart window controls the transmission of visible light and infrared heat into the building, while the new type of solar cell uses near-UV light to power the system. According to Loo, this new technology is actually smart management of the entire spectrum of sunlight.
In a paper published in Nature Energy, the researchers described how they used organic semiconductors—contorted hexabenzocoronene (cHBC) derivatives—for constructing the solar cells. The researchers chose the material because its chemical structure could be modified to absorb a narrow range of wavelengths—in this case, near-UV light. Loo added,
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.
The researchers explained that the near-UV solar cell technology can also power internet-of-things sensors and other low-power consumer products. Loo said,
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.
With inputs from IANS