Stirling engine taps the cold of space to generate power at night

Researchers at the University of California, Davis have developed a novel Stirling engine prototype that generates mechanical power at night by exploiting the temperature difference between the warm ground and the cold of outer space. Unlike traditional engines that require large heat gradients, this Stirling engine operates efficiently with small temperature differences. The device uses a radiative cooling panel pointed at the night sky to shed heat into space, creating a temperature gap sufficient to drive the engine’s piston and spin a flywheel without any fuel input. Testing over a year demonstrated that the system can produce at least 400 milliwatts of mechanical power per square meter, enough to power small devices such as fans or generate electrical current via an attached motor. The technology works best in dry, clear-sky environments and could be applied to ventilate greenhouses or buildings during nighttime when circulation is needed but solar power is unavailable. UC Davis has filed a provisional patent and plans to refine the design and scale up applications, highlighting space as a practical heat sink for continuous