Grace Hahn, a chemist and professor at the University of California, Santa Barbara, traveled from Boston to Southern California. He felt skin discomfort in the hot sun there. From that discomfort, he began to study the effects of the sun on the skin. Once he came to know about ‘DNA photochemistry’. It was with that uneasy feeling of travel in mind that Professor Grace Hahn began research. Grace and his team found a revolutionary way to save green energy or eco-friendly energy from what was once a ‘sunburn’ experience. There are currently only 70 to 80 scientists working on this particular technology worldwide. Scientists hope that this is going to be a milestone for the carbon-free heating system of the future world, starting from keeping temperature-sensitive parts of satellites or airplanes warm.
DNA shape changes
Grace Hahn observed that when the DNA molecules in human skin are damaged or burned by the sun’s ultraviolet rays, they change from their normal straight shape to shrink or bend. A lot of energy is trapped or stored between the molecules in this compressed state. Scientists have been searching for decades for molecules that can change shape in sunlight and store energy. Again, when stimulated as needed, it will return to its original shape and release that energy or heat. In the language of science it is called molecular solar thermal energy storage. It is much like the leaves of a rat trap, which, after being set, act to release the spring as needed.
More powerful than lithium-ion batteries
In a paper published last February, Grace Hahn and her colleagues reported an incredible breakthrough in this technology. Through analysis, they were able to create molecules that could store 1.64 megajoules of energy per kilogram. It has a higher energy density than the lithium-ion batteries used in our mobile phones or electric cars. During laboratory tests, the water inside the test tube began to boil due to the intensity of heat emitted by these molecules.
The main advantages of this technology are:
- Carbon Free Heat Generation: Today, fossil fuels are burned to heat homes or industries around the world. But this technology can store and deliver heat for years in a completely eco-friendly way without burning anything.
- Long term energy storage: Normal batteries cannot hold power for long. But the energy stored in this molecular system can be stored for months, even decades or 40 to 50 years without any loss.
- Geographical Independence: As fossil fuels are limited to certain regions of the world, geopolitical crises often arise. But sunlight is available everywhere on Earth. So this technology can be used in any country.
Current limitations and future goals of scientists
Despite the huge potential, this technology has some limitations, which scientists are now working on. These include—
- Acute UV-Dependence: Changing the shape of these molecules requires intense ultraviolet light of 300 nanometer wavelengths, which is very little in sunlight. Scientists are now trying to adapt it to normal sunlight.
- Uses of Acids: A highly corrosive chemical called hydrochloric acid is currently being used to release the stored energy. Grace Hahn hopes that in the future this energy can be released with just light or other simple means without any toxic chemicals.
- Liquid vs Solid State: Storing this energy in liquid form has complications in pumping it. Therefore, research is currently underway to develop a solid-state or solid version of it for use as a window coating or transparent coating on window glass.
Source: BBC
