Experimental and simulation analysis of a temperature-adaptive radiative cooler with phase change material cover

Passive daytime radiative cooling technology has demonstrated energy-saving potential during the cooling season in buildings. To address the challenge of extra heat loss during the heating season, a temperature-adaptive radiative cooler (TARC) was developed with a phase change material (PCM) cover and a multilayer daytime radiative cooler (DRC). During a warm month when the ambient temperature exceeded 20 ℃, the TARC system demonstrated cooling effects as static DRC, and the TARC and DRC achieved average daytime cooling temperatures of 2.5 ℃ and 4.5 ℃, respectively. However, during a colder period in December, TARC achieved an average temperature in the cooling space higher than the ambient temperature during the daytime due to the PCM cover being able to switch off infrared radiation from DRC and absorb solar radiation. To maximize energy savings in cooling and heating seasons, we established numerical models for the optimization of PCM cover and TARC. The simulation results showed that the optimized TARC could achieve a daily average temperature drop of 4.1 ℃ on a hot day and a temperature increase of 1.0 ℃ on a cold day under the same climatic conditions as the experiments. Further simulations highlight the potential of TARC systems for cross-seasonal applications.