Catenaa, Thursday, November 20, 2025-Researchers at the University of California, Davis, have developed a device that produces mechanical power at night by exploiting the temperature difference between the warm ground and the cold of outer space.
The approach uses a Stirling engine, showing potential for energy generation without sunlight or conventional fuels.
The Stirling engine operates by maintaining one side in contact with a heat source and the other with a cooler environment.
UC Davis engineers adapted this principle, connecting the cold side radiatively to space, while the ground acts as the warm source.
Experiments over a year demonstrated that a single square meter of the device can generate roughly 400 milliwatts of mechanical power.
The team tested the setup outdoors at night, powering a fan directly and driving a small electrical motor.
The design relies on clear, low-humidity conditions, where radiative cooling to space is most effective.
The concept suggests practical applications such as ventilating greenhouses or residential structures during nighttime hours.
Jeremy Munday, UC Davis professor of electrical and computer engineering, explained that Stirling engines are efficient even with small temperature differences, unlike conventional engines that require larger gaps to produce power.
Graduate student Tristan Deppe collaborated on the experimental system, which uses a panel acting as a radiative antenna to channel heat from the engine to deep space.
The study, published in Science Advances, represents a step toward alternative, renewable energy sources that operate continuously, not limited by daylight.
UC Davis has filed a provisional patent for the technology, signaling potential for commercial applications and wider adoption in energy-efficient systems.
