Magnotherm Solutions’ refrigerant-free cooling solution, using magnetocaloric effect solid-state refrigeration, is 15% more energy-efficient than a comparable propane (R290) system, according to Timur Sirman, CEO and Co-Founder of the German startup.
Sirman shared details about the technology, its scalability and the results of a supermarket case study in a presentation at the ATMOsphere (ATMO) Europe Summit 2025. The event was held November 24–25 in Padua, Italy. ATMOsphere is the publisher of NaturalRefrigerants.com.
“With a special metal that gets hot and cold when magnetized and demagnetized, we have a machine that gives hot and cold water like a chiller but without refrigerants,” Sirman said. “This combination of safety and energy efficiency is the value that we can bring to the clean cooling solutions portfolio.”
Magnotherm delivered its first magnetocaloric unit, a 0.04kW (0.01TR) beverage cooler dubbed Polaris, to Coca-Cola in early 2023. “Since then we have built 40 Polaris units and sold 20, making it the first magnetocaloric cooling unit to be reproduced at scale,” Sirman said.
Building on lessons learned from Polaris, Magnotherm developed its second-generation magnetocaloric cooler, Eclipse, which won the Innovation of the Year/Refrigeration award at ATMO Europe 2025. It operates as an air-cooled chiller providing a cooling capacity of up to 1kW (0.3TR). The company has produced five Eclipse units and plans to build 20 more in 2026.
The technology: As a company with 30 employees, Magnotherm originated from research at Technische Universität Darmstadt that focuses on developing magnetocaloric materials that deliver performance comparable to heavy rare earth-based systems while relying on less critical and more cost-effective elements.
- When magnetized, the material’s magnetic moments align, causing it to heat up. When demagnetized, the moments randomize, lowering the temperature by a few kelvins below its initial value.
- Magnotherm uses an active magnetic regenerator (AMR) to increase the cooling span, with a water-based fluid circulating through the system.
- The unit includes a magnetocaloric material block, an AMR with control valves, a rotating permanent magnet assembly, a fluid pump, electronic controls and two water-air heat exchangers for cooling and heat rejection.
The study/scalability: Magnotherm partnered with a supermarket chain that operates tens of thousands of propane display cases to pilot a 0.4kW (0.1TR)-capacity Eclipse by installing the unit in a retrofitted R290 cabinet.
- In the 11-week study, running from May to September, the retailer confirmed that the Eclipse cabinet used 15% less energy than the incumbent propane cases, while maintaining the target temperature of 4‒5°C (39.2 to 41°F).
- “The customer plans to deploy a minimum of 10 more Eclipse units in supermarkets next year,” Sirman said.
- The magnetocaloric technology has the potential to offer a cooling capacity range from 0.1 to 500kW (0.3 to 142.2TR), according to Sirman, with different materials providing a temperature range from −270 to 160°C (−454 to 320°F).
Additional information: Although the unit comes with a higher CAPEX than propane because of the cost of the permanent magnets, Sirman believes that retailers see other OPEX benefits that are hard to quantify, including avoiding the European regulations for refrigerant systems (European Standard EN378).
- The unit operates at atmospheric pressure, with known reliable components and performance-stable magnets that extend the equipment’s life span to over 30 years, according to Sirman.
- If a supermarket’s design includes a semi-plug-in setup, Magnotherm can adapt the Eclipse to tie into the internal heat rejection system, which will shrink the unit’s footprint by 50%.
Quotable: “I am here [at ATMO Europe] to increase trust in caloric cooling,” Sirman said. “We are open to collaboration. Imagine how much more could be achieved in terms of efficiency and performance if more great minds were involved in developing it.”
“With a special metal that gets hot and cold when magnetized and demagnetized, we have a machine that gives hot and cold water like a chiller but without refrigerants.”
Timur Sirman, CEO and Co-Founder of Magnotherm
