Electricity-Free Solid-State Cooling System for Data Centers Prototyped by German and Japanese Researchers

Researchers from the Karlsruhe Institute of Technology (KIT) in Germany and the University of Tsukuba in Japan have unveiled a prototype cooling system that operates entirely without electricity, an innovation that could reshape how data centers manage heat in an era of soaring energy demand. The system, described as the first of its kind to eliminate the need for an electric motor, leverages solid-state elastocaloric technology to convert waste heat directly into cooling power, potentially reducing one of the largest operational burdens facing the industry.

Cooling systems can consume up to 40 percent of a data center's total electricity bill, making efficiency improvements a critical lever for operators grappling with rising power costs and sustainability targets. The new prototype, detailed in the journal Nature Energy, addresses this challenge by coupling two ultra-thin nickel-titanium shape-memory films with complementary functions. When one film is heated by a server or other electronic equipment, it shrinks and converts thermal energy into mechanical work—replacing the electrically driven actuator used in earlier elastocaloric designs. That motion then transfers to the second film, where cyclic loading and unloading induce reversible crystal structure changes that generate cold.

“The crucial innovation is that we combine two complementary functions of shape memory alloys, with one film converting heat into mechanical work and the other film converting this work into cold,” said Dr. Jingyuan Xu, who leads the young investigator group of the ZEco Thermal Lab at KIT’s Institute of Microstructure Technology. “This way, we’re establishing a new approach to drive solid-state cooling, thereby opening up exciting possibilities for the use of waste heat and solar energy.”

In laboratory tests, the prototype achieved a temperature difference of 4°C at an actuator temperature of 86°C, demonstrating feasibility at the component level. By comparison, data center chips typically operate at internal temperatures between 60°C and 85°C, and conventional air or liquid cooling systems can remove 10°C to 20°C of heat. While the performance gap remains significant, the researchers argue that their experiments prove the concept for the first time, offering a pathway toward systems that can match or exceed current technologies through scaling and material refinement.

“We believe that this is only the beginning,” said Dr. Xu. “By scaling up this technology, we want to develop compact cooling systems that leverage abundantly available heat sources for sustainable cooling.” The broader industry is already taking note: in May, UK-based Barocal raised $10 million to commercialize its own solid-state cooling system aimed at data center applications. If successfully scaled, such technologies could not only cut electricity consumption but also enable data centers to repurpose waste heat—a shift that would have profound implications for facility design, energy procurement, and carbon reduction strategies across the sector.