Indian Institute technology Researchers at (IIT) Guwahati have devised an alternative to AC (Air Condition), which IIT claims is not only economical and efficient but also operates without electricity.
The innovation, called ‘radiative cooler’ coating material, can be applied to roofs and functions both day and night to provide an alternative to traditional air conditioners.
Passive radiation cooling systems operate by emitting absorbed heat from the surrounding in the form of infrared radiations that can pass through the atmosphere before being dumped into the cold outer space, explains IIT.
Most of the passive radiative coolers work only at night. For day time operation, these coolers also need to reflect all the solar radiation. So far these cooling systems are not able to provide adequate cooling during the day. Researchers at IIT Guwahati set out to address these issues and come up with a cheaper and more efficient radiative cooling system that can operate round the clock.
The theoretical design of the radiative cooling system has been tested and verified against rigorous computer-based simulations. IIT said that this pattern-free design of the radiative cooler is large area friendly and hence, there is less chance of flaws during the manufacturing process. Therefore, it is expected that the cooling power obtained after the cooler is manufactured will closely match the calculations. With this innovation, cooler manufacturers can now explore radiative cooling to create power-free cooling systems. “The team is hopeful that it will reach the market once the prototype is developed and tested on a large scale for operational stability and durability under various climatic conditions. They are now working in this direction,” IIT said in an official notice. Told.
Ashish Kumar Choudhary, Research Scholar at IIT Guwahati under the supervision of Professor Debabrata Sikdar, Assistant Professor, Department of Electronics and Electrical Engineering, IIT Guwahati, along with his research team designed and modeled such a passive radiation cooler.
Their innovation has recently been covered in a Current Science report, initially published in the Journal of Physics D: Applied Physics by IOP Publishing, United Kingdom.
Highlighting the unique aspects of this innovation, Professor Debabrata Sikdar, Assistant Professor, Department of Electronics and Electrical Engineering, IIT Guwahati said, “Designing a passive radiation cooler for day time operation is more challenging, as it has high Reflection is required simultaneously. High emissivity in the entire solar spectral system (0.3–2.5 µm wavelength) and the atmospheric transmittance window (8–13 µm wavelength).”
In addition, Prof. Debabrata Sikdar said, “These radiation coolers do not require any external energy source for their operation, which is comparable to the conventional air conditioning used to cool buildings and automobiles in countries that experience hot climates such as India. may be one of the best options to replace the system. Unlike traditional cooling techniques, which dump waste heat into the surroundings, radiative cooling is a unique process that allows an object on Earth to send excessive heat directly into the extremely cold universe. cools it down.”
Explaining the technology to overcome the limitations of conventional radiative coolers, Mr. Ashish Kumar Choudhary said, “For a radiative cooler to function during the day, the material must reflect the solar and atmospheric radiations falling on it . Since the materials used in conventional coolers absorb more solar radiation during the day and emit less, they do not work during the day. While daytime cooling can be achieved using polymer-based passive radiation coolers, oxidation degrades the polymers resulting in a limited lifetime.
To address this, innovators considered using thin films of silicon dioxide and aluminum nitride. These materials have a low optical density corresponding to the wavelength range of solar and atmospheric radiations. But at atmospheric transmittance wavelengths, they have high optical density. When the optical density is high, radiation travels slower through a medium and more is absorbed. To remain at thermal equilibrium, the material emits all absorbed radiation like a black body.
“Instead of a single layer, the team cascaded silicon dioxide and aluminum nitride thin film layers onto a silver layer, which was placed on a silicon substrate. The coolers they designed provided about 97 percent reflectance to solar and atmospheric radiations.” and achieved 80 per cent emission for radiations in atmospheric transmittance wavelength. The net cooling power is estimated to be 115 Wm-2 which can reduce the ambient temperature by 15 degrees above the outdoor temperature,” the IIT said in a statement.
read all breaking news, today’s fresh newswatch top videos And live TV Here.