As the use of solar power expands, there is growing attention to the problem of what to do when the sun isn’t shining. The ability to store solar energy when it is available and use it later is the basic solution to the problem. Developing technologies like battery banks and molten salt tanks are currently the major focus.
Recently, however, a team at MIT and Harvard has developed a new material that can store heat from the sun and release it later. The material is a photoswitch – a substance that can assume two different shapes and can jump from one to the other, releasing its stored heat with the application of a small jolt of light, heat, or electricity.
The new photoswitch makes use of a molecule known as azobenzene, which is attached to carbon nanotubes. After years of experimentation, the researchers found that this material could store much more energy than others. They are now exploring a wide range of similar materials to find even better performance.
Applications for such technology could include solar cookers for use in the third world where today’s primary cooking fuels are wood or dung. Photoswitches in a cooker could absorb energy from the sun during the day and then provide heat for cooking in the evening.
There are numerous ways to make use of the sun’s energy. Giant arrays of solar panels are not the only game in town. Some day, self-contained devices that soak up sunshine during the day could be used to provide heat at night.
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A Molecular Approach to Solar Power
Photo, posted March 29, 2012, courtesy of NAIT via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio.