e. peral antunez - renault sa - refrigeranti zeotropici a basso gwp per applicazioni condizionamento...
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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 LLCConsultant MRB CRP
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
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
MRB CRP Sponsors
BOSCH
http://www.exponent.com/
creativethermalsolutions.com/
http://www.sceinc.com/
http://www.haifire.com/
http://www.ilkdresden.de/index.php?L=1http://www.gradientcorp.com/index.html
Science and Strategies for Safe Environments
Independent Labs
R-445A [AC6 refrigerant]
R-744 – 6%
CO O
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
Toxicology of AC6 vs R134a Property CO2 R-1234ze(E) R-134aAcute (LC50) (ppm) Approx. 400,000(1) >207,000(3) >500,000(4)
Anesthetic effects (ppm) 40,000 (30-minutes) >166,000 81,000Cardiac 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 NegativeCarcinogenicity No data(2) No data NegativeASHRAE ATEL (ppm) 40,000 59,000 50,000
1 Mitsuda et al., 19672 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.html5 EPA IRIS file for R-134a
ATEL for AC6 is 54,000ppmOEL is 930ppm
Similar to R-134a
INERIS result with Hot BodyIgnition temperature for AC5/AC6 are
similar and ~100°C higher than 1234yf, and there is a significant time delay in ignition with AC6
Ignition SourcesFinalized table and assessed
different blend concentrationsTested 400 volt sparks
Regional CodesAssessment region per region
Transport & handling (MSDS)Service/Building/Equipment
Flammability
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
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
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
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)
Te
mp
erat
ure
(C
)
R134a Interior Comparison AC6 performance R134a Discharge Comparison AC6 performance
AC6
AC6
Average Interior
Average Vent Outlet
50kph 4th Gear100kph 5th Gear
Idle
Shows R134a comparison data
Life Cycle Analysis
Life Cycle Performance of AC5/AC6/R1234yf is similar, and all are better than R134a
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
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
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
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
Further evaluations ongoing to complete AC6 technical validation : Further FTA assessment based on the
current situationFurther 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
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
MRB CRP Sponsors
Thank You BOSCH