Energy-saving window for versatile multimode of radiative cooling, energy harvesting, and defrosting functionalities

Abstract

This study presents an energy-saving window that integrates the multi-mode of radiative cooling, droplet-based electricity generator, and defrosting/defogging functionalities with an all-in-one device architecture. Constructed with fluorinated ethylene propylene film and indium tin oxide (ITO)/Ag/ITO layers, the window exhibits a transmittance of 0.652 in the visible spectrum, a reflectance of 0.474 in the near-infrared spectrum, and a long wave infrared emittance of 0.972. This transparent radiative cooler effectively reduces temperatures by 5.2 degree celsius on average, compared to the bare glass. Beyond its energy-saving cooling performance, the smart window also serves as a droplet-based electricity generator, producing an impressive instantaneous power of 8.3 W m- 2 when impacted by a single water droplet. Besides, in the presence of fog or frost that impairs the visibility of the smart window, the device can switch to the heater mode and improve the visibility by defogging or defrosting. Lastly, this work examines the practical usage of all multi-modes by incorporating the smart window into the scaleddown model house. In this regard, we expect that this work will not only serve as valuable assets for the technological advancement of the academic study field but also make a significant contribution to energy-saving strategies in real-life situations.