Work

Thermal energy storage mitigates nighttime heating penalty, condensation and frosting risk for passive daytime radiative coolers

Year: 2026

Type: article

Abstract: Passive Daytime Radiative Coolers (PDRCs) provide superior performance for achieving passive cooling in buildings and mitigating urban heat. Recent research has focused on developing modulation solutions to reduce winter overcooling and its associated heating penalty. However, most solutions rely on modulation of PDRCs’ solar absorptivity, addressing daytime only, while the maximum intensity of overcooling is during winter nights. On the other hand, modulation of PDRCs’ emissivity requires external stimuli or complex synthesis processes. Further, the effects of condensation and frosting on PDRCs’ performance remain largely unexplored. Here, we provide a solution that combines sensible and latent thermal energy storage (TES) to mitigate the overcooling, condensation, and frosting of PDRCs during winter conditions. A 15-mm layer of phase change materials (PCMs), with a phase change temperature of 8 °C for winter and 24 °C for summer, and a 50-mm layer of concrete are integrated under PDRCs as TES. The proposed thermal mass-enhanced radiative coolers (TMRCs) also improve the summer cooling performance by utilising condensation as an ancillary cooling mechanism. Compared with a conventional PDRC, TMRCs can increase the surface temperature by up to 8 °C and prolong the non-condensation period by 7.5 hours on a cold winter night, while reducing the peak temperature by up to 7.1 °C on a hot summer day. By mitigating winter overcooling while enhancing summer cooling, this work offers a promising strategy for environmentally adaptive and year-round passive radiative cooling.

Source: Energy and Buildings

DOI: 10.1016/j.enbuild.2026.117144