The document discusses the latest trends in natural refrigerants and their applications in refrigeration systems, highlighting the absence of fundamentally new refrigerant classes. It emphasizes the need for adaptation when transitioning to low-GWP fluids and advocates for the use of natural working fluids in new systems for improved efficiency and reliability. Key trends include advancements in hydrocarbons, ammonia, and CO2 technologies aimed at enhancing energy efficiency and reducing environmental impact.

2. Latest natural refrigerants-based
technology trends in different
applications around the globe
Norwegian University of Science and Technology
Armin Hafner

3. Content
 Introduction
 Latest Technology Trends
 Hydrocarbons
 Ammonia
 CO2
 The way forward

4. Mark O. McLINDEN
National Institute of Standards and Technology, Boulder, USA
1Manuscript ID: 1746; DOI: 10.18462/iir.icr.2019.1746
25th IIR International Congress of Refrigeration, Montreal, Canada, 2019
• carried out database screenings to identify suitable refrigerants
• used PubChem database (Kim et al., 2016), i.e. more than 60 000 000 chemicals
• cycle calculations (simple performance) fluids with low COP and/or volumetric
capacity were screened out.
• The final result was a list of 27 fluids; these comprised hydrocarbons, HFCs, HFOs,
CO2, ammonia, and a total of five compounds with oxygen, nitrogen and/or sulfur.
Introduction
First Conclusion:
…there are no fundamentally new classes of
chemicals available for use in vapor-compression
refrigeration systems…

5. Mark O. McLINDEN
National Institute of Standards and Technology, Boulder, USA
1Manuscript ID: 1746; DOI: 10.18462/iir.icr.2019.1746
25th IIR International Congress of Refrigeration, Montreal, Canada, 2019
• carried out database screenings to identify suitable refrigerants
• used PubChem database (Kim et al., 2016), i.e. more than 60 000 000 chemicals
• cycle calculations (simple performance) fluids with low COP and/or volumetric
capacity were screened out.
• The final result was a list of 27 fluids; these comprised hydrocarbons, HFCs, HFOs,
CO2, ammonia, and a total of five compounds with oxygen, nitrogen and/or sulfur.
Introduction
First Conclusion:
…there are no fundamentally new classes of
chemicals available for use in vapor-compression
refrigeration systems…
Second Conclusion:
…While a drop-in replacement refrigerant requiring no changes to
equipment design is appealing, the properties of low-GWP fluids will
generally be different than the refrigerants they are replacing.
Recognizing and adapting to these differences will be required to
maximize the safety, efficiency, and reliability of new systems….

6. What does this mean?
• Drop with new low-GWP fluids should only be done in
certain cases to keep existing systems in operation
before replaced by a new unit applying natural working
fluids
• New systems should not apply these fluids, because
natural working fluids can do the job more efficient
• Effort (funding) should be given to further improve and
adapt new refrigeration systems to apply natural
working fluids

7. Some of the latest
technology trends
Hydrocarbons
• Home Appliances
• Split AC units
• Light-Commercial refrigeration
• High temperature heat pumps
Ammonia NH3
• Low charge units & Compact chillers
• NH3 /H2O Osenbrück cycle: high temperature heat pumps
• CO2 – NH3 cascade systems for low temperature refrigeration
Carbon Dioxide / CO2
• Commercial Refrigeration including expansion work recovery
• Compressor development
• Integrated Heat Pump Chillers
• Transport Refrigeration
• Below -55°C

8. Which heat pump technology?
Parameter Temperature oC
Heat‐sink inlet 85 – 95 10
Heat‐sink outlet 105 – 115 70 – 90
Ice‐water return 10 12 – 18
Ice‐water supply 0 – 2 7 – 12
Industrial:
• Pasteurization
• Drying
• Steam production
• Etc.
High performance buildings:
• Hotels
• Sport-schools
• SPA / Gym
• Etc.
Goal:
Integrated design
• Utilization of waste heat
Replace boilers
• Primary energy savings
• CO2 emission reduction HC  CO2 
high temp. level high temp. lift
High temperature heat pumps

9. High temperature heat pumps
Proper case for hydrocarbon refrigerants
• High heat sink temperature:  proper selection of fluids and components
• High internal temperature lift and efficiency:  cascade arrangement
R290 R600
R290
R600

10. High temperature heat pumps
Current R&D
Heat management of the R600 compressor:
• Suction temperature <80°C
• Discharge temperature <140°C
Modification of semi-hermetic compressor:
• External discharge manifold (as for CO2 comp.)
• Extended measurement rang of thermal protection to 160°C
• High temperature lubricant
• Oil sump heater
Photo: SINTEF
Dorin

11. Ammonia / NH3
Low charge systems
Combined systems with:
- CO2 cascade systems  low temperature refrigeration
- H2O combined systems  high temperature heat pump

12. Mayekawa ongoing development
25 MW (10 x 2,5 MW) at 80°C hot water supply for
district heating
NH3 charge/skid: 240 kg  ~100 g/kW
As presented at NKM2019 Stavanger Norway

13. Compact Chiller,
without maintenance
Semi hermetic compressor
arrangement – NH3
Workshop on compressor technology
Norsk Kjøleteknisk Møte 2019
Part of space savings can be used for fine separation of oil
• Oil free evaporation possible
• Better efficiency achievable
• Smaller evaporator surface sufficient
• “Low charge” chiller possible
Motor
Screw-
Compressor
Oil separator

14. Combined NH3 - H2O absorption-compression heat pump
Osenbrück 4.0 - Heat Pump Cycle
2H2O
NH3
Heat pump cycle
enables higher sink
outlet temperatures at
lower pressures
compared to pure
ammonia systems
Varying the
composition and
circulation ratios
increases the
flexibility

15. Carbon Dioxide / CO2
Commercial Refrigeration incl. expansion work recovery:
• Ejector technology
• Expander technology
Compressor development:
• Energy efficiency
• Capacity
• Transport refrigeration (bus, train, truck…)
Reported energy savings from field installations

16. BITZER EXPANDER
Goal: capacity boost at high ambient temperatures:
• 20+ % additional cooling capacity at ambient temperatures above 32 °C
• Simple integration in existing CO2 booster units
As presented at Chillventa 2018 &
NKM2019 Stavanger Norway

17. As presented at Chillventa 2018 &
NKM2019 Stavanger Norway
Installation is quite simple and there’s no need to redesign the
refrigeration system.
BITZER EXPANDER

18. As presented at IIR Ohrid 2019*
High efficient compressor technology
Integration of Line Start Permanent Magnet motors (LSPM)
• Case study, based on nominal 36.8 kW motors, for commercial refrigeration
• Compared to previous/current Asynchronous Motors versus the LSPM
motor technology offers a benefit of 6.4 % improved energy efficiency
when performing an SEPR analysis [Seasonal Efficiency Performance Ratio])
BITZER ECOLINE+
* 8th IIR Conference: Ammonia and CO2 Refrigeration Technologies, Ohrid, 2019
doi: 10.18462/iir.nh3‐co2.2019.0025

19. As presented at IIR Ohrid 2019*
High efficient compressor technology
Integration of Line Start Permanent Magnet motors (LSPM)
• Case study, based on nominal 36.8 kW motors, for commercial refrigeration
• Compared to previous/current Asynchronous Motors versus the LSPM
motor technology offers a benefit of 6.4 % improved energy efficiency
when performing an SEPR analysis [Seasonal Efficiency Performance Ratio])
BITZER ECOLINE+
* 8th IIR Conference: Ammonia and CO2 Refrigeration Technologies, Ohrid, 2019
doi: 10.18462/iir.nh3‐co2.2019.0025
significant contribution to reduce
the annual energy consumption

20. GEA StarCO2mpressor
Finally a compact compressor
solution for mobile refrigeration units!
• Bus/Train AC/HP units
• Transport refrigeration

21. Examples successful CO2 system developments
and demonstration
CO2 Chiller / HP
Jordan and Portugal
• Commercial refrigeration units operating in warm climates

22. Example: CO2 Chiller / HP
EVAPORATOR 1
EVAPORATOR 2
DHW
EXTERNAL HEAT
EXCHANGER
(Gas cooler)
MULTI-EJECTOR
BLOCK
COMPRESSOR
RACK
INTERNAL
HEAT
EXCHANGER
LIQUID
RECEIVER
12°C
7°C
90°C
enex ECO2 Chiller / HP
Version of the ¨YUKON gravity¨ family
Compact and energy efficient solution:
• Chilled water for cooling (summer)
• Heat pump function (winter, optional)
• Domestic hot water (all year)
Complies with Eco Design Directive

23. Reported energy savings
Case: CO2 com. Ref. Amman, Jordan
Leapfrogged from HCFC-22 to CO2 in 2018
UNIDO supported the installation delivered by Abdin Industrial Est., Jordan
Annual electricity saving: 40.000 kWh/a
• corresponds to emission reduction of annually 32 metric tons / a of CO2
The 20 kg refrigerant leakage (HCFC-22) which now can be avoided
contributes to an direct emission reduction of annually 35,2 metric tons of CO2.
Manuscript ID: 1044
DOI: 10.18462/iir.icr.2019.1044

24. Reported energy savings
Case: MultiPACK Portugal
Commissioned in late 2018
Integrated CO2 unit (parallel compression + ejector technology):
• LT and MT cooling to all display cabinets and cold rooms
• AC & dehumidification (summer), and heating (winter), applying
a DX Air Handling Unit
www.ntnu.edu/multipack

25. Reported energy savings
Case: MultiPACK Portugal
Annual cost reduction for purchase of electricity in the range of 30.000 €/a,
due to reduced el.-power demand to the refrigeration AC and heating devices.
In comparison a baseline supermarket:
• same size, same location, CO2-HFC cascade design
March 2019 ‐> Sept. 2019
Reference Supermarket*
Daily energy demand
of LT and MT part
www.ntnu.edu/multipack
* With roof top AC split units

26. Summary & way forward
Go Natural Refrigerants!
Saves: Costs
Protects: Environment
Gives: Clear Conscience

27. Questions
are welcome!
armin.hafner@ntnu.no