Danfoss and ENGIE Refrigeration advance R-600a chiller development

Offenbach am Main, Lindau | 27 October 2026

Danfoss and ENGIE Refrigeration are working together to advance the use of R-600a (isobutane) in higher-capacity chiller applications. At Chillventa 2026, the companies presented the latest progress in their joint development project, combining the new Danfoss Turbocor® TNS385 compressor with a dedicated ENGIE Refrigeration chiller prototype. Both the TNS385 and the ENGIE Refrigeration chiller platform remain under development and are not yet commercially available.

The new platform is designed for R600a, a non-fluorinated hydrocarbon refrigerant with favorable thermodynamic properties, low operating pressures and the potential for a reduced refrigerant charge. It combines Danfoss oil-free magnetic bearing compressor technology with ENGIE Refrigeration’s chiller design, connected intelligence and integrated safety concept.

First Danfoss Turbocor® compressor designed for R-600a

The Turbocor® TNS385 is the first Danfoss oil-free compressor designed specifically for R-600a. Following initial laboratory testing at Danfoss, the compressor is now being evaluated with ENGIE Refrigeration in a dedicated chiller prototype. The current development phase focuses on compressor performance, system integration, controls and the safety requirements associated with using R-600a.

The collaboration brings together the complementary expertise of both companies. Danfoss is developing the compressor and contributes its expertise in oil-free compressor technology and applications, while ENGIE Refrigeration contributes its expertise in chiller design, system integration, testing and qualification. By bringing these capabilities together early in the development process, the compressor and chiller can be evaluated as a complete system before commercial introduction.

The TNS385 builds on the established Danfoss Turbocor® oil-free magnetic bearing platform, with specific adaptations for operation with R600a. These include developments to its aerodynamic design, sealing, motor cooling and integrated leak detection. Its magnetic bearing architecture eliminates the need for oil lubrication of the compressor shaft.

Preliminary development data indicate a rated cooling capacity of approximately 385 kW under defined comfort-cooling conditions. Performance figures remain subject to further system validation. The primary focus is comfort cooling for large-building applications.

Energy efficiency guides the design

Energy efficiency guides the design of the prototype that ENGIE Refrigeration develops with Danfoss. The team matches the chiller to the behavior of R-600a, the fluorine-free refrigerant isobutane, and to the oil-free Danfoss Turbocor® TNS385 compressor. The goal is an energy-efficient comfort-cooling chiller for large buildings. The ongoing prototype evaluation tests this goal. Danfoss and ENGIE Refrigeration will publish efficiency data once validation is complete.

Moreover, as an A3 refrigerant, R-600a requires specific consideration of safety at system level. Safety is therefore integrated into the compressor and ENGIE Refrigeration has designed the chiller as well to initiate automatic protective measures and safe shutdown sequences.

Combining compressor and chiller expertise

Fabio Klein, Divisional President, Danfoss Commercial Compressors says:

„Developing technologies for new refrigerant applications requires close collaboration at system level. Working with ENGIE Refrigeration allows us to bring compressor and chiller expertise together early in the development process and evaluate performance, integration and safety requirements before commercial introduction. This collaboration gives us valuable learnings from the complete system as we continue to validate the technology together with customers and partners.”

Jochen Hornung, CEO, ENGIE Refrigeration says:

„We are delighted to combine our respective strengths with our long-standing partner Danfoss Turbocor. We deliberately join Danfoss Turbocor's compressor expertise with ENGIE Refrigeration's expertise in developing innovative chillers. In doing so, we lay the foundation for solutions that align with current and upcoming regulatory requirements. At the same time, we pursue a shared vision for the cooling and heating generation of tomorrow.”

Development continues toward controlled release

Both the TNS385 and the ENGIE Refrigeration chiller platform remain under development. Danfoss plans a controlled release of the TNS385 during 2027, subject to successful completion of the remaining validation and qualification activities.

The initial phase is intended to support close collaboration with selected customers and continued learning around application, safety and system-integration requirements before broader commercial availability is considered. The ENGIE Refrigeration chiller platform remains under development, and no commercial-release date for the complete chiller is being announced at this stage.