A new review led by researchers at Karlsruhe Institute of Technology (KIT) examines how close caloric cooling is to real-world use. The technology replaces conventional refrigerants with solid-state materials, and according to KIT, prototypes have now moved beyond pure lab demonstrations. The review was published in Nature Energy.
What is caloric cooling?
Caloric cooling uses materials that heat up when an external stimulus is applied and cool down again when it is removed. According to KIT, that stimulus can be a magnetic field, an electric field, pressure or tensile strain. In a device, this effect can be used to absorb heat in one place and release it somewhere else, much like in a refrigerator.
“Caloric cooling offers two key advantages: It does not require refrigerants with a high global warming potential and can reduce energy consumption,” said Dr. Jingyuan Xu, who led the review as responsible author. Xu heads the ZEco Thermal Lab, the Zero-Emission and Environmentally Friendly Heating and Cooling Technologies group at KIT’s Institute of Microstructure Technology (IMT).
Why cooling demand is rising
KIT points to several pressures on cooling systems:
- According to the German Meteorological Service, June 2026 ended with a historic heat wave.
- Energy demand for space cooling is expected to more than double by 2050.
- AI is increasing cooling demand, as more powerful data centers generate more waste heat and must protect their servers from overheating.
- Cooling also matters in electronics, medicine and logistics.
Today, most of this demand is met by vapor-compression systems. KIT notes that the technology is mature but consumes large amounts of electricity and can be noisy because of its compressors.
How far caloric cooling prototypes have come
The review shows that some prototypes now deliver meaningful cooling power:
- Magnetic systems exceed three kilowatts, a range relevant for larger cooling applications.
- Mechanically driven prototypes have passed the one-kilowatt mark.
- Electric-field devices are smaller and could suit electronics or wearables.
The Nature Energy abstract adds that recent advances, including fatigue-resistant shape memory alloys, multilayer electrocaloric designs and natural rubber-based elastocaloric systems, have improved durability, power density and cost-effectiveness.
The gap between materials and devices
Despite this progress, a gap remains between what the materials can do and how finished devices perform. KIT lists heat losses, material fatigue and incomplete work recovery during the cooling cycle as the main reasons.
“The material can show large temperature changes in the laboratory,” said first author Dr. Kun Wang of IMT. “What matters, however, is how efficiently this effect can be used for cooling in a device.”
The review’s roadmap highlights durability above all. Devices must stay stable over many millions of cycles to cool reliably for years. They also need to absorb and release heat quickly and use as little energy as possible per cycle.
Where caloric cooling could be used first
According to KIT, caloric systems will not replace established cooling technology in the short term. The first applications are expected where very quiet operation is needed, or where refrigerants with a high global warming potential must be avoided.
As a writer, I think the jump to kilowatt-scale prototypes is the most important signal here, because it moves the field from lab curiosity toward real machines. For more on cooling and energy, read about 800-volt DC power in AI data centers, the Rio Tinto and Rondo heat battery, and Compal’s ARC Cloud AI infrastructure deal.
FAQ
What is caloric cooling?
It is a solid-state cooling method that uses materials which heat up and cool down under magnetic or electric fields, pressure or tensile strain, instead of conventional refrigerants.
How powerful are caloric cooling prototypes?
According to KIT, magnetic systems exceed three kilowatts and mechanically driven prototypes have passed one kilowatt.
When will caloric cooling be used?
KIT says it will not replace established systems in the short term. First uses are expected where quiet operation is needed or high-GWP refrigerants must be avoided.