Simultaneously and Synergistically Harvest Energy from the Sun and Outer Space

The sun and outer space are the two most important fundamental thermodynamics resources for human beings on Earth. The capability for harvesting solar energy has been of central importance throughout the history of human civilization. Harvesting the coldness of outer space using radiative cooling technology also has a long history and has received renewed interest recently. However, simultaneously and synergistically harvesting energy from these two thermodynamics resources has never been realized. Here we report the first experimental demonstration of such simultaneous energy harvesting using a configuration where a solar absorber that is transparent in mid-infrared is placed above a radiative cooler. The solar absorber is heated to 24°C above the ambient temperature and provides a shading mechanism that enables the radiative cooler to reach 29°C below the ambient temperature. This work points to a new avenue for harvesting of renewable energy resources.