Performance analysis of switchable radiative cooling and solar heating for building energy-saving

Radiative cooling and solar heating are two renewable energy technologies for clean cooling and heating, offering promising building energy-saving solutions. However, their static spectrum properties cause overcooling or overheating. This study investigates the effects of switchable radiative cooling and solar heating on building energy consumption using a new strategy. Experiments in three small-scale rooms (i.e., radiative cooling room, solar heating room, and reference room) show that radiative cooling reduces energy consumption by 29.1 % in summer but increases it by 4.1 % in winter, while solar heating saves 15.6 % energy in winter but raises consumption by 27.8 % in summer, proving the effectiveness of radiative cooling in hot conditions and solar heating in cold conditions. In addition, large-scale building energy consumption simulations confirm the superior performance of the dynamic regulation strategy among the vast majority of regions. Furthermore, three different dynamic regulation strategies are proposed and analyzed, including open-loop control strategy, passive feedback strategy, and active feedback strategy. The active feedback strategy can reach 40.62 % energy savings (40.38 GJ) in La Paz, while the passive feedback and open-loop control strategies achieve 36.72 % (36.50 GJ). Comparison results show that the open-loop control strategy and the passive feedback strategy are sensitive to the environment, while the active feedback strategy has the best energy-saving effect.