Switchable Cavitation in Silicone Coatings for Energy‐Saving Cooling and Heating

TLDR

Space cooling and heating currently consume large amounts of energy and cause environmental problems. The study proposes a switching strategy for energy‑saving cooling and heating using silicone coatings that can be reversibly tuned from a porous to a transparent solid state. The coatings are made from commercially available, cheap materials via a facile, environmentally friendly method, are durable, reversible, patternable, and can be applied immediately to various existing objects including rigid substrates. In the porous state the coatings reflect 93 % of solar radiation and emit 94 % of long‑wave infrared, achieving a ~5 °C sub‑ambient drop at ~35 °C, while in the transparent solid state they transmit 95 % of sunlight, raising ambient temperature from 10 to 28 °C in cold weather.

Abstract

Space cooling and heating currently result in huge amounts of energy consumption and various environmental problems. Herein, a switching strategy is described for efficient energy-saving cooling and heating based on the dynamic cavitation of silicone coatings that can be reversibly and continuously tuned from a highly porous state to a transparent solid. In the porous state, the coatings can achieve efficient solar reflection (93%) and long-wave infrared emission (94%) to induce a subambient temperature drop of about 5 °C in hot weather (≈35 °C). In the transparent solid state, the coatings allow active sunlight permeation (95%) to induce solar heating to raise the ambient temperature from 10 to 28 °C in cold weather. The coatings are made from commercially available, cheap materials via a facile, environmentally friendly method, and are durable, reversible, and patternable. They can be applied immediately to various existed objects including rigid substrates.