A Stirling engine works by having one side exposed to a heat source while the other side is kept cooler. “If you simply place it on a table, it won’t generate any power on its own, because all sides are at the same temperature,” Munday explained.

Figure 1. Tapping Space’s Chill to Generate Power at Night.

Typically, a temperature difference is created by heating one side of an engine, often by burning fuel. But Munday and graduate student Tristan Deppe asked whether they could instead link the cold side to something extremely cold—yet far away: deep space. Figure 1 shows Tapping Space’s Chill to Generate Power at Night.

“It doesn’t need to touch space directly; it just needs to exchange heat radiatively,” Munday explained. It’s similar to standing outside on a clear, cold night: heat radiates away from your body, and you quickly start to feel chilled.

Testing the Radiative Cooling Concept

To test the idea, Deppe and Munday placed a simple Stirling engine—essentially a piston driving a flywheel—on a panel that acts as a heat-radiating antenna, then set the whole setup outdoors at night. The ground provided the warm side, while the panel radiated heat toward the cold expanse of space.

A year of nighttime experiments showed that the small device could produce at least 400 milliwatts of mechanical power per square meter. The team used it to directly power a fan and also coupled it to a small motor to generate electricity.

The results demonstrate that useful amounts of power can indeed be drawn from the night sky. According to Munday, the effect is strongest in dry regions with clear night skies. Potential applications include ventilating greenhouses or residential buildings without relying on conventional energy sources.

The Idea Behind the Engine

Introduce the concept: a Stirling engine requires a temperature difference to produce power. Instead of heating one side with fuel, researchers thought: what if the other side could tap into the extreme cold of space? This sets up the fundamental principle of radiative cooling.

How Radiative Cooling Works

Explain the physics: objects lose heat by radiating it into space. Even without direct contact, a surface facing the night sky can become colder than the surrounding air, similar to how your body feels cold on a clear night.

Building the Prototype

Describe the experimental setup: a Stirling engine mounted on a heat-radiating panel, with the ground as the warm side and the panel “pointing” toward space as the cold side. The panel acts like an antenna, channeling the cold effectively.

Nighttime Testing and Results

Share the findings: after a year of experiments, the small device produced at least 400 milliwatts per square meter. The power was sufficient to drive a fan and generate electricity through a small motor.

Applications and Future Potential

Discuss practical uses: the concept works best in dry regions with clear skies and could power small devices, ventilate greenhouses, or even assist residential buildings. It’s a renewable, off-grid way to harness the cold of space for nighttime energy.

Source: SciTECHDaily

Cite this article:

Priyadharshini S(2025), Engine Harnesses the Cold of Space to Produce Nighttime Power, AnaTechMaz, pp.425