This document summarizes research on applying carbon dioxide (R744) refrigeration technologies in supermarkets located in warm climates. It describes SINTEF, a Norwegian research organization that conducted the study. The document outlines different R744 refrigeration system designs and evaluates their annual energy consumption in various global cities using temperature data. It finds that R744 systems with ejector-supported parallel compression can achieve the highest efficiencies. The research concludes that R744 technologies provide efficient and global solutions for refrigeration and may outperform hydrofluorocarbon systems when considering total cost of ownership over the lifetime of the equipment.

1. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
SUPERMARKETS
IN WARM CLIMATES
APPLYING R744 REFRIGERATION
TECHNOLOGIES.
Dr. Armin Hafner
SINTEF Energy Research
Norway

2. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
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SINTEF - A contract research organization based in Trondheim,
Oslo, Bergen, Stavanger and Tromsø
•SINTEF is one of the largest independent research organisations in Europe.
Social perspective
SINTEF wishes to contribute to the creation of value
and to a society in healthy sustainable development.
Business concept
SINTEF sell research-based knowledge and related
services to Norwegian and international clients.
Fundamental values
Honesty, Generosity, Courage and Unity
SINTEF has 2145 employees,
1600 situated in Trondheim and
430 in Oslo.
Norway

3. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Content
• Introduction
• Alternative R744 Technologies
• Selected global locations from each continent
• Comparison of annual energy consumption
• Summary and Outlook

4. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Introduction
• Supermarkets consume ~4 % of the national
electricity in Europe
• Majority of systems apply HFC's with high GWP
• CO2 (R744 ) is the preferred alternative of the
end-users across Europe in the future
• Predictable – no restrictions
• Proven technology with potential
• Integrating required functions (+ AC, heat recovery
& heat pump)
• Global perspective

5. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Baseline
R744 Booster
• Low cost option
• Well proven
• Good efficiency in
moderate climate
conditions
• Several 1000 units
in Europe

6. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
R744 baseline booster
+ Sub-cooling unit
• Well proven baseline
• Additional cost for
Sub-cooling unit
• Challenges with
reliability due to HX
• Few units in operation

7. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
• Performance boost at
high ambient temperatures
• 30% of expansion work
recovered for compression
• Flooded evaporators
• -2,5 °C suction temp
• all time, even at subcritical operation
Accumulator
R744 Ejector supported
parallel Compression

8. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Performance of commercial ref. systems
Ambient Temperature [°C]
COP
Ref: Finckh 2011

9. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Measured and simulated performance

10. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Annual temperature bins for selected cities
Source Meteonorm
North
America
South
America
South
Europe
Africa India China Australia

11. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Relative annual energy consumption
Local HFC systems are set to 100%.

12. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Relative annual energy consumption.
HFC system located in city (*) are set to 100% for the continent.
30
40
50
60
70
80
90
100
110
120
130
*ElPasoTX
LosAngeles
Chicago
NewYork
*Rio
Santiago
Punta…
Panama
*Roma
Madrid
Lisbon
Athens
*Mombasa
Dakar
Cairo
CapeTown
*Mumbai
Chennai
Kolkota
NewDelhi
*Beijing
Shanghai
Guangzhou
Hangzhou
*Darwin
Melbourne
Perth
Sydney
rel.Energyconsumption[%]
(*HFC_region=100%)
R744 Ejector R744 / R290 mec. Subcooler HFC404A Standard R744 Booster

13. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Summary
• Central and Northern Europe current R744 units give
lowest total cost of ownership
• Only energy consumption compared, not included:
• -> direct refrigerant emissions (HFC & HCFC)
• HFC production emissions
• R744 ejector supported units with parallel compression
provide the highest energy efficiency values
• Global solution
• Efficient integration of AC possible
• Education and training required for a rapid introduction

14. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
• Many pilot installations all across Europe
• Decision makers are able to consider R744 units as real options
for Southern Europe, Asia, Africa, America and Australia,
Innovation related to R744 units will support to
outperform commercial refrigeration units applying
HFC not limited to the GWP issue due to system
leakage. More important are energy efficiency and
total cost of ownership of these units, which have to
run 24/7 for decades.
Outlook

15. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Thank you very much for your attention!
Contact:
Armin.Hafner@sintef.no

16. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Multi-Ejector block
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• Compact design,
made in cooperation
with Danfoss
• Six fixed geometry nozzles
• 6-100 kW cooling capacity
Photo: Enex srl www.enex.it
6+12+6+12+25+50

17. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Evolution of R744 Commercial Refrigeration
17
R744 simple Booster
(Baseline)
• Simple
• Many units in the
market
• Flash gas bypass
• Low cost (below
HFC in
Scandinavia)
• COP baseline for
moderate – cold
ambient temp.
Parallel Compression
• Advanced system
• Higher investment
cost
• Flash gas (auxiliary)
compression
Ejector System
• Advanced system
• Flooded evaporators:
• possible
• simple (no pump)
• Pre-compression
• Higher load on
Auxiliary compressors
COP
+ 10%
COP
+ 10-20%

18. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Ejector system ≠ Ejector system
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Classic Ejector
• High pressure control with
needle in motive nozzle
• High eff. at design point
• Part load operation
challenges
• Low motive flow rate and
• Large mixing chamber
• Requires oil return strategy
• Ejector off (low pumping
ability) – superheat operation
of evaporators
• Discontinues operations
Liquid Ejector only
• Enables flooded
evaporators all year
• Applicable for
booster and parallel
compression system
• Simple on/off control
• Requires low pressure
accumulator
Ejector supported parallel
Compression
• Fixed nozzle ejectors: designed
for pumping liquid and pre-
compressing vapour (Multi-
Ejector block)
• Enables flooded evaporators all
year, requires low pressure
accumulator
• Higher load on auxiliary
compressors.
• Pressure lift can be adapted to
provide efficient AC
Venturi type
• Part load challenges

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Example: 'Multi Ejector' Supermarkets in CH
Ref: Eric Wiedenmann, ATMOsphereEurope 2015