Danfoss advances oil-free compressor technology for R600a through system-level collaboration

The TNS385 is the first Danfoss oil-free compressor designed specifically for R600a. 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 R600a.

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 of the prototype that ENGIE Refrigeration develops with Danfoss. The team matches the chiller to the behavior of R600a, the fluorine-free refrigerant isobutane, and to the oil-free 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, R600a 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.

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 announced at this stage.

Follow Danfoss Climate Solutions channels for updates as development progresses.