Scientists create transparent film that could harvest sunlight by day, release heat on demand later to keep you warm.
Researchers at MIT created a new material that can store solar energy during the day and release it later as heat, whenever it’s needed. The transparent polymer film could be applied to many different surfaces, such as window glass or clothing.
Above: The layer-by-layer solar thermal fuel polymer film comprises three distinct layers (4 to 5 microns in thickness for each). Cross-linking after each layer enables building up films of tunable thickness. Credit MIT
Although the sun is a virtually inexhaustible source of energy, it’s only available about half the time we need it — during daylight. For the sun to become a major power provider for human needs, there has to be an efficient way to save it up for use during nighttime and stormy days.
The key to enabling long-term, stable storage of solar heat, according to the team lead by MIT professor Jeffrey Grossman, postdoc David Zhitomirsky and graduate student Eugene Cho, is to store it in the form of a chemical change rather than storing the heat itself.
Whereas heat inevitably dissipates over time no matter how good the insulation around it, a chemical storage system can retain the energy indefinitely in a stable molecular configuration, until its release is triggered by a small jolt of heat (or light or electricity).
Ted Sargent, university professor at the University of Toronto, who was not involved in this research, said:
“This work presents an exciting avenue for simultaneous energy harvesting and storage within a single material.”
Eugene Cho, said that manufacturing the new material requires just a two-step process that is “very simple and very scalable.” The system is based on previous work that was aimed at developing a solar cooker that could store solar heat for cooking after sundown, but “there were challenges with that,” he added.