Mechanical Deformation Induced Continuously Variable Emission for Radiative Cooling

TL;DR

This paper introduces a mechanically deformable photonic structure that enables continuous regulation of radiative cooling temperature, offering adaptive thermal management for energy-efficient buildings.

Contribution

It presents a novel reconfigurable photonic structure using PDMS deformation to achieve continuously variable radiative cooling spectra, a capability not previously reported.

Findings

The structure can reach different stagnation temperatures under specific strains.

Mechanical deformation causes fluctuation of the cooling temperature around a set point.

The system demonstrates dynamic temperature regulation through strain variation.

Abstract

Passive radiative cooling drawing the heat energy of objects to the cold outer space through the atmospheric transparent window (8 um - 13 um) is significant for reducing the energy consumption of buildings. Daytime and nighttime radiative cooling have been extensively investigated in the past. However, radiative cooling which can continuously regulate its cooling temperature, like a valve, according to human need is rarely reported. In this study, we present a concept of reconfigurable photonic structure for the adaptive radiative cooling by continuously varying the emission spectra in the atmospheric window region. This is realized by the deformation of the one-dimensional PDMS grating and the nanoparticles embedded PDMS thin film when subjected to mechanical strain. The proposed structure reaches different stagnation temperatures under certain strains. A dynamic exchange between two different strains results in the fluctuation of the photonic structure's temperature around a set temperature.