Beam-controlled spectral-selective architecture with planar polydimethylsiloxane/metal-films for all-day radiative cooling

TL;DR

This paper presents a scalable, planar PDMS/metal-based radiative cooling device with beam-controlled spectral selectivity, enabling continuous all-day cooling during daytime with minimal environmental dependence, potentially reducing global energy use.

Contribution

It introduces a cost-effective, large-area scalable thermal emitter with beam control and spectral selectivity for daytime radiative cooling, demonstrating practical outdoor performance.

Findings

Achieved 9.5°C and 11.0°C temperature reduction in lab and outdoor tests.

Demonstrated continuous all-day cooling with ~120 W/m² power in outdoor experiments.

Implemented spectral-selective solar shelter to suppress daytime solar input.

Abstract

Radiative cooling is a passive cooling strategy with zero consumption of electricity. Although this technology can work well during optimal atmospheric conditions at nighttime, it is essential to achieve efficient radiative cooling during daytime when peak cooling demand actually occurs. In this article, we report an inexpensive planar polydimethylsiloxane (PDMS)/metal thermal emitter, i.e., a thin film structure fabricated using fast solution coating process that is scalable for large area manufacturing. By manipulating the beaming effect of the thermal radiation, temperature reduction of 9.5 {\deg}C and 11.0 {\deg}C were demonstrated in the laboratory and out-door environment, respectively. In addition, a spectral-selective solar shelter architecture was designed and implemented to suppress the solar input during the daytime. Due to the enhanced directionality of the thermal emission, the dependence of the radiative cooling performance on the surrounding environment was minimized. Out-door experiments were performed in Buffalo NY, realizing continuous all-day radiative cooling with an average power of ~120 W/m2 on a typical clear sunny day at Northern United States latitudes. This practical passive cooling strategy that cools without any electricity input could have a significant impact on global energy consumption.