Zero-energy switchable radiative cooler for enhanced building energy efficiency

. Fossil fuel consumption for heating and cooling represents a considerable portion, approximately half, of the world's total energy use, thereby presenting a substantial challenge in diminishing dependence on these energy sources. Our study presents the design and fabrication of a zero-energy switchable radiative cooler (ZESRC) to address the global climate crisis by reducing energy consumption within buildings. ZESRC utilizes a simple morphology-driven method that exploits materials' differing thermal expansion coefficients, enabling a seamless switch between cooling and heating modes at any preset temperature point, enabling superior adaptive thermal management. Field experiments demonstrate that, relative to ambient temperature, ZESRC usage results in a maximum temperature decrease of 7.1 degrees C during summer and a maximum increase of 7.5 degrees C in winter. Furthermore, we developed an energy-efficiency map for different climate zones, showing the ZESRC's superiority over devices with only solar heating or radiative cooling, cutting building energy use by 14.3%. The results underscore the ZESRC's capability for net-zero energy consumption, significantly advancing global energy conservation and the 2050 net-zero carbon goal.