Daytime radiative cooling with polymer coatings

Tawadud AlKatheeri, Aikifa Raza, Jin You Lu, Tie Jun Zhang

Research output: Contribution to journalConference articlepeer-review

Abstract

Cooling is a significant end-use of energy and a major driver of peak electricity demand in hot-climate countries. In contrast to traditional cooling methods that require power and bulky equipment to carry heat away, radiative cooling is a passive and natural way of cooling on the earth. Recently, passive cooling using selective reflectors and emitters have attracted worldwide attention. These radiative cooling devices demonstrate great potential owing to their ability in reflecting the majority of incident solar radiation while maintaining strong emissivity in the mid infra-red wavelength range. In this work, a scalable polymer coating is developed to efficiently radiate heat to the outer space through an atmospheric transparency window between 8-13 µm (1300-800 cm-1). The proposed polymer coating on a reflective metallic layer exhibits near-perfect IR emissivity and good daytime radiative cooling capability, while conventional polymer coating absorbs sunlight in very wide spectrum. The proposed radiative cooling coating shows more than 90% reflectance of the solar spectrum with resistance to UV radiation. Roof-top experiments and radiative cooling analysis are performed to evaluate radiative cooling performance is designed and fabricated to quantify the power during daytime. Preliminary results confirm that the proposed radiative approach is promising and cost-effective for large-scale and energy-efficient cooling applications.

Original languageBritish English
Pages (from-to)8307-8312
Number of pages6
JournalInternational Heat Transfer Conference
Volume2018-August
DOIs
StatePublished - 2018
Event16th International Heat Transfer Conference, IHTC 2018 - Beijing, China
Duration: 10 Aug 201815 Aug 2018

Keywords

  • IR emission
  • Polymer coatings
  • Radiative cooling
  • Selective emitter
  • Solar reflection

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