1. XV EUROPEAN CONFERENCE MILANO 7th-8th JUNE 2013 CSG
Latest Technology in Refrigeration and Air Conditioning
Under the Auspices of the PRESIDENCY OF THE COUNCIL OF MINISTERS
PROGRESS ON DEVELOPING
LOW GWP ZEOTROPIC
REFRIGERANTS FOR MAC
APPLICATION
Mr E Peral-Antunez, Renault S.A.
Leader of the CRP project team and presenting author
Dr R E Low Mexichem UK Ltd.
Author for correspondence on properties of the refrigerants
Mr W R Hill, MACRAE LLC
Consultant MRB CRP

2. Presentation Outline
• Overview of MRB CRP
– MAC Refrigerant Blend Cooperative Research Project
• Key Differences in blend vs pure refrigerant
• Toxicology
• Flammability
• Material Compatibility
• Performance
• Risk Assessment
• Service and Factory Fill
• Phase III Scope

3.  CRP formed under rules of SAE in Feb 2011
 OEM & Tier Ones involved
 Chaired by OEM representative with SAE support
 Engaged experts with refrigerant assessment experience
 CRP focused on technical assessment of multiple factors in parallel
 Risk Assessment
 Flammability
 Performance
 Materials Compatibility
 Hose material development
 Compressor Durability
 Service and Factory Fill Equipment
 Developed suggestions for future SAE standards
 MRB considered two fluids, AC5 and AC6, in phase I
 The team has agreed to moving with AC6 as the best option
during Phase III evaluation
CRP overview

4. MRB CRP Sponsors
BOSCH

5. http://www.exponent.com/
creativethermalsolutions.com/
http://www.sceinc.com/
http://www.haifire.com/
http://www.ilkdresden.de/index.php?L=1
http://www.gradientcorp.com/index.html
Science and Strategies for Safe
Environments
Independent Labs

6. R-445A [AC6 refrigerant]
R-744 – 6%
CO O

7. What’s different about a
Blend??
• Made up of three components rather than one
– AC6 uses refrigerants currently in production
• Has temperature glide in the evaporator and
condenser
– Opportunity to improve performance with an optimized heat
exchanger
– Potential to use in heat pump system
• Components of the blend may leak at different rates
from hoses and seals
– Composition to be checked and if necessary corrected prior
to recharging in service

8. Toxicology of AC6 vs R134a
Property CO2 R-1234ze(E) R-134a
Acute (LC50) (ppm) Approx. 400,000(1) >207,000(3) >500,000(4)
Anesthetic effects (ppm) 40,000 (30-minutes) >166,000 81,000
Cardiac sensitization no
effect level (ppm)
Not tested/not
expected
120,000(3) 50,000(4)
Worker exposure limit
(ppm)
5,000 ppm
(8-hour TWA)
40,000 (IDLH)
800(3) 1,000
28-day NOAEC (ppm) No data 5,000(3) 50,000(4)
90-day NOAEL (ppm) No data 5,000(3) 50,000(4)
Developmental toxicity
NOAEL (ppm)
No data 15,000(3)
10,000 [rats](5)
40,000
[rabbits](5)
Genotoxicity No data(2) Negative Negative
Carcinogenicity No data(2) No data Negative
ASHRAE ATEL (ppm) 40,000 59,000 50,000
1 Mitsuda et al., 1967
2 Not expected to be a significant concern given that CO2 is a normal constituent of the human environment.
3 AIHA draft WEEL (2011)
4 http://www.epa.gov/ozone/snap/refrigerants/safety.html
5 EPA IRIS file for R-134a
ATEL for AC6 is 54,000ppm
OEL is 930ppm
Similar to R-134a

9.  INERIS result with Hot Body
 Ignition temperature for AC5/AC6 are similar and
~100 C higher than 1234yf, and there is a
significant time delay in ignition with AC6
 Ignition Sources
 Finalized table and assessed different blend
concentrations
 Tested 400 volt sparks
 Regional Codes
 Assessment region per region
 Transport & handling (MSDS)
 Service/Building/Equipment
Flammability

10. Flammability summary
 AC6 anticipated characteristics are as follows* :
USA EU
AC5/R-1234yf AC6 AC5/R-1234yf AC6
MAC system
application
A2L A2L A2L A2L
Transport &
handling [MSDS]
Flammable
Non-
flammable
Flammable
Non-
flammable
Service Flammable Flammable Flammable Flammable
Building codes Flammable Flammable Flammable
Reduced
flammability
May benefit from non-flammability
below 50C in implementation
(interpretation of Seveso directive)
Will be flammable by ATEX
*based on test data generated to date

11.  Permeation Testing
Total permeation results are similar to R1234yf
 Selective permeation not significant at 30-75C
 R744 leakage increases more rapidly above 75C
 Oil testing
 Four different oils evaluated from sponsors
 Results similar to previous oils tested
 Miscibility of oils is better in AC5/AC6 than with R1234yf
 Compatibility testing
 Ten different hose configurations tested
 Certain PA materials had issues, similar to those with R1234yf
 Some current materials are acceptable for use
 Eight different O-ring materials were also evaluated
 Worst Case contaminant testing showed no significant
effect
Material compatibility

12.  Cooling capacity evaluation in vehicle tests
 Performance of AC6 nominal composition is similar
to R134a
 LCCP calculation
 AC5 and AC6 are similar to R1234yf
 All much better than R134a
Performance & Efficiency

13. Cool-down Performance [Drop-In]
Performance of nominal concentration is similar to R134a
AC6 PullDown Test Comparison to R134a
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80 90
Elapsed Time (Min)
Temperature(C)
R134a Interior Comparison AC6 performance R134a Discharge Comparison AC6 performance
AC6
AC6
Average Interior
Average Vent Outlet
50kph 4th Gear
100kph 5th Gear
Idle
Shows R134a comparison data

14. Life Cycle Analysis
Life Cycle Performance of AC5/AC6/R1234yf is similar, and
all are better than R134a

15.  Technology identification
 Plan to add R-744 to vehicle charge just prior to
charging vehicle
 Prototype machine development
 Working with CINETIC to validate process …
 Validation by physical testing
 Final validation part of Phase III
 First tests in June 2013
 Equipment anticipated proven by October 2013
Vehicle manufacturing Equipment

16. Service Equipment
 Technology identification
 Plan to add R-744 as needed to assure proper
concentration in vehicle
 Prototype machine development
 Equipment Development is on-going
 Process likely to be similar to factory fill
 Validation by physical testing
 Planned in Summer 2013

17. Overall Risk Assessment Conclusions
 Use of AC6 in MAC systems poses an extremely low
level of risk for vehicle operators and repair workers
 The risks are lower than those estimated for R-1234yf
 Based on Risk Assessment to date, AC6 could be
an appropriate alternative for R134a and R12 as MAC
refrigerants
 Increased risk due to flammability is very small
 Hazard due to toxicity is equivalent or reduced
 Environmental benefits (i.e., GWP, ODP, LCCP) are enhanced as
compared to R-134a and R-12
 Newly collected data are consistent with and support
these prior conclusions

18. Risk Comparison to Other Vehicle Events
Event Probability per vehicle
per operating hour
Probability of being in a police reported vehicle collision 5 x 10-5
Probability of vehicle collision due to vehicle brake failure 3 x 10-7
Probability of highway vehicle fire (any cause) 1 x 10-7
Probability of an airbag-related fatality associated with a vehicle collision 2 x 10-10
Probability of vehicle occupant/former occupant experiencing HF exposure above
health based limits associated with R-1234yf ignition/decomposition. 2 x 10-14
Probability of vehicle occupant/former occupant experiencing HF exposure above
health based limits associated with AC6 ignition/decomposition. 1 x 10-14
Probability of vehicle occupant being exposed to an open flame due to R-1234yf
ignition 4 x 10-15
Probability of vehicle occupant being exposed to an open flame due to AC6
ignition 5 x 10-17

19.  Further evaluations ongoing to complete AC6
technical validation :
 Further FTA assessment based on the current
situation
Further Flammability Studies
 Further heat exchanger evaluations
 New hose materials evaluation
 Validate Factory Fill and Service Equipment
 Support of SAE Standards development
 Support for USEPA SNAP submission
CRP Phase III

20. Conclusions
• Basic evaluation is completed for AC6
– Materials
– Compressor
– Performance
– Risk
• Factory Fill and Service validation to be
completed this Summer
• Updated Risk Assessment to be
complete this Summer
• Technical Issues complete in Fall, 2013

21. MRB CRP Sponsors
BOSCH