Reverse-switching radiative cooling for synchronizing indoor air conditioning.

Switchable radiative cooling based on the phase-change material vanadium dioxide (VO) automatically modulates thermal emission in response to varying ambient temperature. However, it is still challenging to achieve constant indoor temperature control solely using a VO-based radiative cooling system, especially at low ambient temperatures. Here, we propose a reverse-switching VO-based radiative cooling system, assisting indoor air conditioning to obtain precise indoor temperature control. Unlike previous VO-based radiative cooling systems, the reverse VO-based radiative cooler turns on radiative cooling at low ambient temperatures and turns off radiative cooling at high ambient temperatures, thereby synchronizing its cooling modes with the heating and cooling cycles of the indoor air conditioning during the actual process of precise temperature control. Calculations demonstrate that our proposed VO-based radiative cooling system significantly reduces the energy consumption by nearly 30 % for heating and cooling by indoor air conditioning while maintaining a constant indoor temperature, even surpassing the performance of an ideal radiative cooler. This work advances the intelligent thermal regulation of radiative cooling in conjunction with the traditional air conditioning technology.