Trane® leverages Solstice® technology to drive cooling and heating innovation

As world-wide demand grows for increasingly efficient products to reduce energy and resource consumption, cooling and heating technology companies are focused on system design that integrates safety, performance and lower environmental impact.



One such business – Trane® – is leading the way in leveraging the performance benefits of Honeywell’s Solstice® low Global Warming Potential (GWP) refrigerants to develop a new generation of HVAC-R systems, replacing refrigerants such as R-134a scheduled for phasedown under F-Gas regulations.

The partnership with Honeywell has enabled Trane® to create new process cooling and heating systems focused on combining low environmental impact with enhanced performance. This includes the launch of its new CITY range, which widens the operating map of compact cooling and heating solutions for smaller commercial buildings by successfully integrating Solstice® ze with screw  compressor technology.


As part of its Global Climate Commitment, in 2014, the company committed to a 35% reduction of its greenhouse gas (GHG) footprint from its own operations by 2020. To deliver on this goal, the company targeted a 10% increase in energy efficiency from a 2013 baseline – and has achieved the goal two years ahead of schedule.


« By adopting Honeywell’s Solstice® technology, we have created solutions that improve performance for customers while also improving the environmental impact of refrigerants to the very minimum. »

Erik Van Oossanen, Portfolio Manager, Applied Chillers Europe Trane®



The Needs



  • Identify low GWP refrigerants that would meet the exacting requirements of the Ingersoll Rand portfolio of EcoWise products, enabling customers to reduce their GHG footprint and save money without sacrifcing performance or safety.


  • Successfully integrate the selected refrigerants into new product designs to guarantee equivalent or better performance than  predecessor refrigerant and chiller combinations.


  • Adopt refrigerants that not only enhance performance but are proven to be safe to use, are non-toxic and non-flammable*.


  • Equip customers against the spiralling costs associated with F-Gas HFC phasedown refrigerants, such as R-134a.

*Solstice® ze  is non-flammable below 30 °C.



The Solution



  • Honeywell’s new generation HFO refrigerants have been widely adopted by Trane® for its cooling and heating systems. In 2014, Trane® specifed Solstice® zd (R-1233zd), with a GWP = 1, for its ECTV centrifugal chillers and then went on to integrate Solstice® ze (R-1234ze), GWP <1, in 2016 for its screw and magnetic levitation chillers and water-to-water heat pumps.

  • In 2018, the company unveiled a breakthrough innovation, harnessing the potential of Solstice® ze to widen the operating conditions within the capacity range of scroll compressors to create its new compact CITY cooling and heating offer with screw compressor.

  • The new operating conditions reach -12 °C for process application cooling as well as 80 °C for heating purposes.



 The Benefits



  • Created wider operating maps for Trane® chillers and heat pumps, opening up new product design opportunities, including the new CITY range of HVAC-R products.


  • Enhanced system performance in established markets, including data centre applications, and new products for process industries using negative temperature applications, such as food and beverage, replacing natural refrigerants that require signifcant safety mitigation systems.


  • Helped improve overall efficiency, with the potential to lower the total cost of system ownership.


  • Provided environmental preferable solutions that are safe and reliable, offering a near zero GWP alternative to natural refrigerants without any of the inherent safety concerns.


  • Opened up new process cooling and heating system design innovations, stretching the capacity reach at both ends of the spectrum from 150 kW up to 2800 kW, enabling the introduction of new screw compressor chiller and heat pump systems.



CITY Innovation

Trane® has always taken a leadership position in environmental stewardship by helping building owners meet environmental preferable goals without compromising efficiency, reliability or safety. Now Trane® has developed a new HVAC range for smaller buildings that opens up a new market segment.

Until now, there has been no scroll compressor solution using a <1 GWP refrigerant that could deliver the required capacity. However, the operating map of Solstice® ze has enabled Trane® to launch its new compact CITY cooling and heating solutions based on screw compressor technology, offering products ranging from 150kW – 400kW.

There are three CITY concepts :

•  CITY Comfort : cooling in tight city buildings – the system fits a standard elevator for ease of installation.
• CITY Booster : a heat pump for water sources at 5–30 °C, including district heating schemes and wastewater sources, elevating output temperatures to up to 80 °C, from 67 °C achievable previously.
•  CITY Process : a dedicated cooling design for process applications down to -12 °C (typically food and drink), overcoming the toxicity and flammability safety concerns associated with ‘natural’ refrigerants.




With its new CITY range, Trane® has created a new HVAC product that stretches the capacity reach of screw compressor technology, thanks to the application of Solstice® ze.
This configuration enables enhanced heating solutions to be delivered, with heat pump output temperatures now elevated to 80 °C – allowing building owners to move away from fossil fuel heating systems.


« The use of R-1234ze aligns perfectly with our Climate Commitment while supporting our customers’ sustainability initiatives. In 2014, Ingersoll Rand publicly committed to increase its energy efficiency and reduce greenhouse gas emissions (GHG) related to its operations and products – the adoption of low GWP refrigerants is very important to these environmental goals and also in helping our customers achieve their own targets. »

Erik Van Oossanen, Portfolio Manager, Applied Chillers Europe, Trane®




The Solstice® Advantage 


Solstice® ze

Solstice® ze refrigerant (HFO-1234ze) is an ultra-low GWP alternative to traditional refrigerants for energy-effcient chillers and/or commercial air conditioning in supermarkets and commercial buildings. With a GWP <1 – a 99.9% reduction in direct impact versus R-134a – it also meets key performance, cost effectiveness and safety criteria.

Solstice® zd

Solstice® zd (HFO 1233zd) is a non-flammable, ultra-low GWP replacement for R-123 for low pressure centrifugal chillers, offering better capacity and similar efficiency to R-123. With a GWP=1, this refrigerant also offers great potential in high temperature heat pumps. Major chiller manufacturers have already announced product ranges based on Solstice® zd.


Solstice® ze and Solstice® zd do not form TFA during composition.