A PVA /Gelatin Composite Aerogel With Synergistic Radiative Cooling and Thermal Insulation for Energy‐Efficient Building Applications

ABSTRACT To address the vicious cycle caused by high energy consumption and greenhouse gas emissions of traditional temperature control equipment, this paper focuses on passive radiative cooling technology and develops a polyvinyl alcohol (PVA)/gelatin (GE) composite aerogel that combines radiative cooling and heat insulation functions. The composite aerogel is prepared by a freeze‐drying process, in which a stable composite structure is formed through the hydrogen bond interaction between PVA and GE molecules. This structure retains the intrinsic advantages of single‐component aerogels, such as low density and high porosity, while significantly improving mechanical properties and optimizing pore size distribution. The experimental results demonstrate that the PVA‐GE composite aerogel exhibits an ultralow thermal conductivity of 0.03280 W/(m·K). It also shows a high average solar reflectance of up to 91% over the entire solar spectrum, together with a mid‐infrared (8–13 μm) emissivity of 94%. As a result, the composite aerogel achieves sub‐environmental cooling of up to 11.4°C during daytime conditions and effectively mitigates the issue of excessive cooling at night. The synergistic combination of radiation cooling and thermal insulation endows this composite aerogel with broad application potential in thermal management for intelligent energy‐efficient buildings, providing an effective pathway toward the development of low‐cost, scalable, and sustainable temperature regulation materials.