MIT News October 30, 2019
An international team of researchers (USA – MIT, Chile) has developed polyethylene aerogel (PEA)—a solar-reflecting (92.2% solar weighted reflectance at 6 mm thick), infrared-transparent (79.9% transmittance between 8 and 13 μm at 6 mm thick), and low-thermal-conductivity (kPEA = 28 mW/mK) material that can be integrated with existing emitters to address these challenges. Using an experimental setup that includes the custom-fabricated PEA, they demonstrated a daytime ambient temperature cooling power of 96 W/m2 and passive cooling up to 13°C below ambient temperature around solar noon. This work could greatly improve the performance of existing passive radiative coolers for air conditioning and portable refrigeration applications. The technology has applications in preserving produce in remote locations and providing an initial cooling stage for electric refrigeration, thus minimizing the load on those systems. It can be integrated with existing air conditioning systems to improve efficiency. Theoretically, such a device could achieve a temperature reduction of as much as 50 C, so they are continuing to work on ways of further optimizing the system so that it could be expanded to other cooling applications…read more. Open Access TECHNICAL ARTICLE
Schematic of the proposed approach. Credit: Science Advances 30 Oct 2019: Vol. 5, no. 10, eaat9480, https://advances.sciencemag.org/content/5/10/eaat9480