Worldwide, cooling systems consumes almost 17% of the total generated electricity and it’s also responsible for 10% of greenhouse gas emissions. With the increasing population, the demand for refrigerators and air conditioners will increase and according to estimations, by 2050 the rate will increase by tenfold. That’s a huge number. Right! So what we can do (at-least in this case) is find a way to reserve energy by making energy efficient cooling systems, but it’s not easy.
At the Stanford University, a team of researchers has developed an innovative cooling technology that cooled water without electricity. They achieved it by releasing the appropriate amount of heat where it won’t affect anything, i.e., space. This technology can have possible application on domestic refrigerators and conditioning.
‘The current research is based on our previous work on the radiative cooling system, but this time it’s with far advanced technology,’ said Raman, co-author of the paper.
Sending Heat to the Space
Radiative cooling is naturally occurring process in which a body loses heat due to thermal radiation. It can be witnessed by anyone under normal conditions. For example, you must have noticed the heat coming out of road after sunset especially during the summer. The phenomena of Radiative heat is mostly noticeable with clear sky at night. Without clouds, the heat we emit can easily penetrate the atmosphere and gets lost in the space.
‘By any chance if you have something cold, very cold like space you can drain heat into it, then you won’t need electricity to do cooling. It (heat) just flows, and that’s why the amount of terrestrial heat, which goes out of our atmosphere into the universe is just colossal, said Shanhui Fan, one of the authors of the paper.
Journal reference: Sub-ambient non-evaporative fluid cooling with the sky
Even though, our bodies release heat through radiative cooling, it won’t be effective during a bright sunny day in summer. This is due to the fact that on a hot day your body will absorb more heat than you can release it, simple. To solve this problem, the research team is using a multilayer optical film that will reflect most of the sun’s radiations while emitting surface thermal energy out of our atmosphere simultaneously. Without most of the incoming heat from the sun, the radiative cooling phenomena can make cooling below the air temperature possible even on a sunny hot day.
‘This technology breaks us free from temperature barrier, though we are still bound by something more complex and colder – the space,’ said Eli A. Goldstein, co-author of the paper.
The experiments published in 2014 were performed using small wafers of a multilayer optical surface, about 8 inches in diameter, and only showed how the surface itself cooled. Naturally, the next step was to scale up the technology and see how it works as part of a larger cooling system.
Currently, SkyCool Systems is calculating the total amount of energy saved when these panels are attached to conventional air conditioning systems at their test facilities. But Fan and Raman are hopeful that this technology will soon power other home appliances. While, researchers are focused on making panels compatible with standard home appliances for now, they are eager to test their technology for industrial cooling systems.