UC Davis Engineers Generate Electricity from the Cold Night Sky

UC Davis Engineers Generate Electricity from the Cold Night Sky
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Engineers at the University of California, Davis (UC Davis) have demonstrated a novel device capable of generating electricity by harvesting the natural cooling of the cold night sky, according to Earth.com.

This technology utilizes the principle of radiative cooling, where the Earth continuously leaks heat into space as infrared light on clear nights. The small, outdoor engine, led by Dr. Jeremy Munday, uses the night sky as a cold reservoir. The setup effectively maintains a strong temperature difference between its warm ground plate and its cool sky-facing radiator. This temperature difference is enough to power a Stirling engine, an external heat engine that thrives on small temperature gaps.

In experiments conducted in Davis, the device successfully delivered usable shaft power, running near one turn per second and capable of running a small fan. The team reported potential for outputting several watts per square meter with improved components. This breakthrough demonstrates a new way to harvest nighttime energy passively, with the strongest potential appearing in arid zones and at high, dry elevations where air moisture is scarce.