Synchronous Radiative Cooling and Thermal Insulation in SiO₂/Poly(vinyl alcohol) Composite Aerogel for Energy Savings in Building Thermal Management

Abstract

Daytime passive radiative cooling is an effective way to reduce energy consumption for building cooling. However, overcooling might occur in radiative cooling at low-temperature which presents limitations in thermal management. Herein, a new SiO2/poly(vinyl alcohol) composite aerogel with nanomicro–multistage porous structure for thermal insulation and radiative cooling was fabricated by a non-solvent-assisted freeze-drying strategy. In the fabrication process, the nonsolvent (acetone) for poly(vinyl alcohol) was utilized to control the proportion and size of the macro-porous structure inside the SiO2/poly(vinyl alcohol) composite aerogel, making the thermal conductivity of the aerogel decreased to 0.0390 W/mK while spontaneously increasing its solar reflectance and infrared (8–13 μm) emissivity to 93.70% and 98.19%, respectively. The composite aerogel achieved sub-ambient cooling of up to 14.1 °C during the day and above-ambient warming of 3.8 °C at night, avoiding nighttime overcooling. The SiO2/poly(vinyl alcohol) composite aerogel demonstrates adaptive thermal management compared to commercial insulation materials, making it suitable for intelligent thermal management of energy-saving buildings.

Eco-Friendly Tourmaline@MOF Lignocellulose Aerogel with Favorable Fire Retardancy and Smoke Suppression for Insulation Materials

“…Environmental pollution and energy consumption are the two major problems, − in the modern society. The energy consumption of buildings accounts for about 30–50% of the total energy consumption in the world. , Furthermore, fires caused by buildings occasionally occur and cause great harms to humans and the environment . Therefore, manufacturing of novel insulation materials with highly efficient thermal insulation and fire prevention by green and low-carbon methods is important.…”