Solar Power For When The Sun Doesn't Shine: New Material Uses Chemical Method To Store Sun's Energy
A major challenge to the large-scale use of solar energy is that sun is usually required, and sometimes it doesn't shine. Now a team of researchers at Massachusetts Institute of Technology and Harvard University are confronting that obstacle with a new material that absorbs the sun's heat and stores the energy in chemical form so it can be released when needed, MIT News reported.
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"It could change the game, since it makes the sun's energy, in the form of heat, storable and distributable," said Jeffrey Grossman, an associate professor of materials science and engineering at MIT, and co-author of the paper describing the new process, which was published in the April 13 online edition of the journal Nature Chemistry.
"Large-scale utilization of solar-energy resources will require considerable advances in energy-storage technologies to meet ever-increasing global energy demands," the authors said in the abstract of the study, titled "Templated Assembly of Phototswitches Significantly Increases the Energy-Storage Capacity of Thermal Fuels."
"Our results demonstrate that solar thermal fuels composed of molecule-nanostructure hybrids can exhibit significantly enhanced energy-storage capabilities through the generation of template-enforced steric strain," said the authors.
Steric strain is the increase in potential energy of a molecule due to repulsion between electrons in atoms that are not directly bonded to each other, according to the chemcial information website of Utah Valley University.
The researchers found their method of solar storage promising for producing energy used for heating buildings, cooking, or generating power for industrial processes that use heat. Their solution, however, remains inefficient for all uses of electricity, they said.
Their findings are based on the principle that some molecules, known as photoswitches, can assume two different shapes, as if hinged in the middle. When exposed to sunlight, the molecules absorb energy and change from one configuration to the other, which is then stable for long periods of time. When the photoswitches are triggered by a small jolt of light, heat or electricity, they return to the other configuration and give off heat.
"In effect, they behave as rechargeable thermal batteries, taking in energy from the sun, storing it indefinitely, and then releasing it on demand," according to MIT News.
The findings have a distinct advantage when it comes to concerns about global warming and climate change.
Unlike fuels that are burned, this system uses material that can be continually reused. It produces no emissions and nothing gets consumed, Boston.com reported.
The researchers developed the material after they used computer analysis to devise a concept for it three years ago. The study's lead author, Timothy Kucharski, a researcher at MIT and Harvard, said the team's latest research means commercial production of such a system is now "a big step closer," but further study will be needed to create a practical system.
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