Three birds with one stone strategy: A tri-modal radiator based on the cooling-compensation-heating effect

Passive radiative using solar energy for energy gain is receiving increasing attention as a green and sustainable energy supply method. However, passive radiative designs of existing materials are usually static and unsuitable for dynamic seasonal and weather changes. Here, we explore an efficient design of a temperature-adaptive thermal management sandwich structure that integrates passive daytime radiative cooling/heating and temperature control of phase change materials. Compared with conventional passive radiators, the developed phase change material-enhanced radiative cooler/heater (PDHM) can be flipped to adjust thermal management performance according to seasonal and diurnal temperature changes. The radiative cooling layer (PDRC) has a high solar reflectance (95%) and a high infrared emissivity (97%). The phase change layer (PCM) acts as an effective compensation for temperature, causing the PDRC cooling power to rise and fall by 15 W·m−2 during daytime and nighttime. The radiative heating layer (PDRH) has a low infrared emissivity (75.6%) and a high solar absorptivity (85.7%). The final PDHM aerogel achieves 11 °C below ambient temperature and 25 °C above ambient temperature under direct sunlight in summer and winter, and it leads to an increase in the average nighttime temperatures of 2.1 °C and 1 °C in summer and winter, reducing the diurnal temperature difference. Thus, the temperature-adaptive PDHM shows great potential for passive radiative regulation, which can further extend the application of passive radiators.