Switchable radiative cooling based on phase-change materials

For adaptive thermal management, it is desirable to achieve switchable radiative cooling, where cooling can be adjusted or turned on and off based on environmental conditions. We introduce multilayer structures with the phase-change material germanium-antimony-tellurium (GST) for switchable radiative cooling. Our system is based on two components: a wavelength-selective filter on the top and a radiative cooler at the bottom, separated by a large air gap. We calculate the net cooling power of our system, which depends on the emissivity of the radiative cooler in the presence of the top filter, by solving the heat balance equation. We use a memetic optimization algorithm to optimize both the material composition and the layer thicknesses of the multilayer filter and cooler structures. We show that our optimized system can achieve a very high net cooling power when the GST layers in the cooler are in their crystalline phase. By switching the GST layers in the cooler to their amorphous phase, our system can achieve a near zero net cooling power. Our proposed switchable radiative cooling system could advance the thermal management of buildings, smart windows, vehicles, and textiles.