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