The do-it-yourself cooler design uses Scotch® tape and aluminum foil to achieve cooling without the use of electricity or refrigerants
SPIE--International Society of Optics and Photonics
Picture: Scientists have designed a zero-carbon, zero-energy cooler, which uses the most common household items-scotch tape. see more
Image credit: Jyotirmoy Mandal and Aaswath P. Raman of the University of California, Los Angeles.
Due to the ongoing discussion of climate change, the term "greenhouse effect" became part of the public vocabulary decades ago. The greenhouse effect is a natural phenomenon that describes how heat from the sun is captured by gases in the earth's atmosphere in the form of radiation. But there is still a lot of radiation lost to outer space, because these wavelengths are difficult to absorb by atmospheric gases. These wavelengths constitute long-wavelength infrared (LWIR) radiation.
Using this natural phenomenon to cool objects is called passive radiant cooling. In short, passive radiant cooling involves placing objects under the sky to reduce their temperature. Several materials, such as paint and polymers, have been developed to ensure better radiant cooling, but these materials are difficult to manufacture and have different properties.
However, in a recent study published in the Journal of Energy Photonics (JPE), scientists at UCLA’s Samueli School of Engineering have developed a do-it-yourself (commonly known as DIY) radiation cooler made of scotch tape and aluminum foil. And other household materials. The device is proposed as a research standard. "Our equipment is not only flexible, robust, expandable, and low-cost, but it is also manufactured using commercially available materials. This makes it attractive as a convenient and repeatable standard with selective emissivity to measure other equipment and Materials," said Aaswath P. Raman, the corresponding author of the study.
The adhesives and plastic films used in Scotch® tapes have chemical bonds that can absorb and radiate heat at the LWIR wavelength, which makes them an attractive choice for passive radiant coolers. The research team created a design consisting of two layers of tape on aluminum foil. Then they took optical measurements of the cooler and found that the design had moderately selective infrared emission. "Selectivity" here refers to the proportion of heat lost through LWIR radiation in the main atmospheric window compared to radiation at all wavelengths. They also tested another design with sputter-coated silver because it absorbs less solar radiation than aluminum foil.
They found that at night, the aluminum design can achieve a temperature that is 7°C lower than the ambient temperature. They also saw that the sputtering silver plating design can achieve a temperature drop of 2-3°C during the day. Finally, they tested the first design with a polyethylene convection hood (an additional layer used to reduce heat absorption) and found that they can achieve a temperature drop of up to 11°C. “The significant cooling we achieved can be further used to generate electricity through the thermoelectric process,” explains another corresponding author, Jyotirmoy Mandal.
Perhaps the most important part of this research is its reproducibility. The wide availability and production consistency of 3M Scotch tape make it a reliable standard for heat coolers. Aluminum foil is also easily available, and each brand has relatively constant characteristics. These factors contributed to the argument for using scotch tape and foil design as the standard reference for all future heat cooler designs. There is also no clear boundary to classify the selectivity of heat emitters. This design can serve as such a threshold.
Peter Bermel, Associate Editor of JPE, pointed out: “This work provides a way to'democratize' the potential impact of radiant cooling for various low-cost applications in the research environment.” To encourage its adoption as a standard, the research team has adopted it. Extensive design optical performance experimental data is published online.
Read the open access article written by Xin Huang, Jyotirmoy Mandal, and Aaswath P. Raman, "DIY radiant cooler as a radiant cooling standard and cooling component for device design", J. Photon. Energy 12(1), 012112 (2021), doi 10.1117/1.JPE.12.012112. This article is part of the JPE Radiant Cooling Special Series, guest editors by Aaswath P. Raman (University of California, Los Angeles), Xiaobo Yin (University of Colorado Boulder) and Peter Bermel (Purdue University).
Journal of Energy Photonics
The do-it-yourself radiant cooler is used as a radiant cooling standard and cooling component for equipment design
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SPIE--International Society of Optics and Photonics
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Copyright © 2021 American Association for the Advancement of Science (AAAS)