Anti-greenhouse effect via regulation of surface emissivity

Infrared radiation serves as a cooling channel when an emitting surface is directly exposed to the atmosphere. However, the cooling performance is restricted, or it might be transitioned to heating mode in an enclosure. In this study, we develop a design strategy to modify the surface emissivity to mitigate radiative heating in an enclosure comprising of two (i.e., a floor and a cover) gray bodies. Indoor heating experiments were performed on a copper enclosure with a view factor of 0.67, and it was demonstrated that rationally designed surfaces lowered the floor and cover temperatures by 11 °C and 2 °C when they were heated at 115 °C and 48 °C, respectively. Heat transfer simulations verified the experimental results, further indicating that the heat dissipation capability was improved with an increase in the view factor from floor to cover and the in-plane thermal conductivity of a cover. This study will provide useful guidelines for the development of passive cooling structures in an enclosure such as buildings, automobiles, electronic devices, and batteries.