Abstract
Research on radiative cooling has attracted recent widespread interest owing to the potential for low-cost passive structures to enable large-scale thermal energy management. Using a generalized effective medium theory, we theoretically show that two-layer films comprised of SiO2 and Si3N4 nanoparticle layers on an Ag back reflector exhibit superior radiative cooling compared to single-layer or two-layer dense solid films, and can outperform other reported designs. The performance enhancement is a result of the ability to tune the nanoparticle fill fraction, which improves the spectral match between emissivity of this structure and the atmospheric transmission window. We also propose a standardized method for comparing the performance of radiative cooling structures reported by the research community.
Highlights
Forty percent of the world population lives in consistently hot regions, many of which have homes lacking air conditioning [1,2,3]
Using a generalized effective medium theory, we show that simple two-layer nanoparticle films composed of separate layers of SiO2 and Si3N4 particles on a silver back reflector can outperform all dense solid laminate thin films and provide a cooling performance superior to those reported previously [8,9,10,11,12]
We find that two-layer nanoparticle films always outperform dense solid laminate thin films and are sufficient to achieve cooling performances greater than or similar to previously reported structures [8,9,10,11,12]
Summary
Forty percent of the world population lives in consistently hot regions, many of which have homes lacking air conditioning [1,2,3]. Graded index and periodic layered structures are constrained by the limited portfolio of materials that can be used to achieve the stringent broadband reflection and emission requirements of a daytime radiative cooler [31]. Optimized two-layer nanoparticle film designs have higher cooling power than optimized dense solid laminate thin films, regardless of which structure or composition is chosen. These results support the idea that random nanoparticle laminate films could provide a feasible alternative to dense solid thin film or patterned designs, provided scalable synthesis techniques can be identified. Plasma synthesis or ball milling could be considered as possible scalable deposition methods [22,32]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
