New 3D-printed tech uses metal wires instead of gases for sustainable cooling

Researchers in Germany are showcasing sustainable climate-control technology at the Hannover Messe show.

The team from Saarland University and the Saarbrücken Center for Mechatronics and Automation Technology (ZeMA) conceptualized it around elastocaloric technology.

Through stretching and releasing special “shape memory” metal wires, the system creates heat or cold without using harmful chemical gases.

This provides a greener, simpler way to control temperature compared to standard air conditioning and heating.

Use of nickel-titanium

As global cooling demands surge due to climate change, elastocaloric technology offers a highly efficient, electric-powered alternative to existing systems.

Recognized by both the European Commission and the World Economic Forum as a top emerging innovation, this method relies on the unique physical properties of a nickel-titanium alloy.

These alloys reduce harmful emissions and improve energy efficiency, advancing sustainable, carbon-neutral temperature control.

Interestingly, this new work has evolved from simple wires to complex 3D-printed shapes that maximize surface area to boost cooling power.

Researchers tested various designs to ensure the metal performs at its best for maximum cooling and heating power.

For this, intricate, “striking” metal cubes were designed for maximum energy efficiency. While these 3D-printed structures look like decorative art, their complex geometries are engineered to optimize heat transfer within the system.

Engineers can efficiently “pump” thermal energy out of spaces like cooling chambers by stretching the metal to release heat and absorbing cold.

“This is the next stage in the development of elastocaloric technology. The research we are currently undertaking on these new structures is still in the realm of basic research—but we are already thinking about practical use and developing solutions for real-world applications,” explained Professor Paul Motzki.

Long-term stability

Nickel-titanium is a shape-memory alloy that switches between two crystal structures to transfer heat.

When the metal is stressed, it releases heat to its surroundings (exothermic); when the stress is removed, it absorbs heat, causing it to cool down (endothermic).

This mechanical heartbeat allows the material to act as a heat pump without complex machinery.

Also, because the metal’s electrical resistance changes when it is stretched, it essentially feels its own movement. This allows the system to automatically track its own position and status, without requiring any additional sensors.

The next version of these devices will cool more effectively by using a porous metal structure with much greater surface area.

This design allows the cooling medium—either air or water—to flow directly through the material, enabling much faster, more effective thermal energy transfer than traditional methods.

To make this tech ready for homes and stores, the team is focusing on making it tough enough to last for years and easy to fix. This ensures it can work reliably in everyday appliances like refrigerators.

Experiments are also being conducted to ensure the technology survives the rigors of daily use, aiming for a lifespan of over one million cycles.

To keep the parts from breaking, researchers are fine-tuning the metal to withstand constant stretching and squeezing.

Furthermore, maintainability is also prioritized, recognizing that all materials eventually wear out. For this, modular components can be designed for quick, easy replacement. It will ensure the system remains reliable for long-term commercial deployment.

The technology is currently being showcased at Hannover Messe from 20 to 24 April (Hall 11, Stand D41).