German and Japanese researchers have demonstrated a small cooling device that operates without electrical input, using waste heat to create mechanical motion and then produce a cooling effect. If it can be scaled up and improved, the approach could reduce the energy, water use and environmental impact associated with cooling datacentres and other electronics.

The Karlsruhe Institute of Technology and University of Tsukuba team used two thin nickel-titanium shape-memory foils: heat causes one to move, powering the loading and unloading of the other. Their prototype achieved a 12.9K temperature span at the refrigerant-film level and 4.0K at device level under 86°C heating; with a 130°C external heat source, it maintained a 2.2K device-level span. The technology remains at an early laboratory stage, with larger experimental systems planned.