# Recent Experiences in MAC System

Development

“New Alternative Refrigerant

Assessment ” 

# Technical Update

Enrique Peral

- Antunez, Renault

[Chair Person]

9/28/2011

# Announcing....

M AC R efrigerant B lend



# [MRB] Cooperative Research Program



# [CRP]

9/28/20113



# MRB CRP Sponsors

9/28/20114



# GROUP MOTIVATION

1. 

# To investigate use of zeotropic alternative low GWP refrigerants for Mobile Air Conditioning to meet EU Regulation and obtain credits in the USA

2. 

# To evaluate ways to optimize the balance of refrigerant properties for current and future application in MAC

3. 

# To evaluate the Life Cycle Energy Consumption

4. 

# To assess options that may increase availability of refrigerant to meet Global Regulatory Requirements for MAC

5. 

# Expand scope of risk assessment methodologies to cover new vehicle types

9/28/20115



# CRP Overview

 

# CRP formed under rules of SAE

 

# OEM & Tier Ones involved

 

# Chaired by OEM representative with SAE
support

 

# Engage experts with refrigerant assessment experience

 

# CRP focused on technical assessment of multiple factors in parallel

 

# Develop proposals for future SAE standards

 

# MRB is considering two fluids, AC5 and AC6;

 

# Today’s presentation will focus on AC6 owing to time constraint, but similar data generated for AC5

9/28/20116



# Why look at two fluids?

AC5

 

# Very close pressure to



# R

- 134a/R

- 1234yf

 

## Similar capacity

 

# Mildly flammable (similar to R

- 1234yf)

 

# Temperature glide similar to zeotropic fluids used in stationary

sector 

# AC6

 

# Slightly higher pressure



# fluid than R

- 134a

 

## Potentially higher capacity

 

# Reduced flammability compared to R

- 1234yf

 

# Temperature glide larger than currently used refrigerants

 

# Future use in heat pump
systems

9/28/20117



# Timing

MRB CRP Timing

2010 2011 2012



### Task Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Jan Feb Mar Apr 

### Planning

Fault Tree Development

Toxicity Assessment

Performance tests

Flammability

Ignition sources
Refrigerant Decomposition

Permeation Testing
Materials testing
Oil compatibility/etc.



### Vehicle Evaluations

Compressor endurance tests

Service and handling

SAE Standards

Final Reports



## CRP MRB has virtually completed main part of technical evaluation

9/28/2011 

## Green=completed



## Yellow

- To be completed8



# Independent Labs

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

9/28/20119 

# Glide of zeotropic refrigerants

 

## When a zeotropic fluid evaporates or condenses the 

## composition of liquid and vapour vary as the vapour fraction (quality) increases or decreases

 

## And the temperature changes through the phase change

process

 

## The components don’t take turns in evaporating: there is 

## always evaporation of all components.

 

## Our test results on AC6 clearly show the temperature glide is present and clearly show that the heat transfer is not impaired

 

## Need to consider blending tolerance and composition effects in assessing flammability

 

## Methods for assessing this exist (ASHRAE)

 

## We have used these in the

assessment

9/28/201110



# Flammability

 

# R

- 1234yf flammability risk was assessed in previous CRP1234

 

# Extensive testing was involved

 

# Flammability risk was considered acceptable by

CRP and US EPA

 

# MRB CRP desires to identify a lower or 

# ideally non flammable refrigerant

 

# Assessment items

 

# Flammability limits

 

# Flame speed

 

# Ignition sources

 

# Decomposition products

 

# Regulations

9/28/201111 9/28/2011 

# Basic flammability data

LFL vol % UFL vol %

AC5 23 ° C/50% RH [WCF] 

### 8.25 13.65

AC5 60 ° C/50% RH [WCFF] 

### 8.35 18.3

AC6 23 ° C/50% RH [WCF] Not flammable Not flammable

AC6 60 ° C/50% RH [WCFF] 

### 7.1 11.75

R

- 1234yf 23 ° C/50% RH* 

### 6.25 NA

R

- 1234yf 60 ° C/50% RH 

### 6.55 12.70

* From ASHRAE submission 

### Limits in air using ASHRAE

- 34 apparatus and protocol

Resistance

in circuit 0 K

Ohm 1000 K

Ohm

AC5 WCF 5000 4050

AC6 WCF >5000 >5000

R

- 1234yf >5000 >5000 Minimum Ignition Energy in dry air

at 23 ° C [mJ]



## WCF=Worst Case Formulation 

## WCFF=Worst Case of Fractionation, for Flammability

 

# AC6 burning velocity is lower than R

- 1234yf

 

# Heat of combustion for both refrigerants similar to

R

- 1234yf12 

## AC5 AC6 R

- 1234yf

Blower resistor No
Ignition No

Ignition No

Ignition*

Blower module 

## No
Ignition 

## No

Ignition 

## No

Ignition*

12 volt battery cable TBD TBD TBD

Friction sparks No
Ignition No

Ignition No

Ignition 

# Ignition Source Test

9/28/2011 

### *Based on previous testing at INERIS13 

## AC5 AC6 R

- 1234yf

Wire

- to

- wire short 

## No
Ignition 

## No

Ignition 

## No

Ignition*

Relay No


## Ignition No



## Ignition No



## Ignition*

Headlight filament Ignition No
Ignition No

Ignition

PTC heater Ignition No
Ignition Ignition* 

# Ignition Source Test

9/28/2011 

### *Based on previous testing at INERIS14 

# Ignition Temperature with a hot surface

Summary....with oil

• AC5 and AC6 equivalent and not significantly different than without oil

• Higher ignition temperature for both AC5 & AC6 (+100 ° C) compared to R

- 1234yf

0 ° C 750 ° C 850 ° C

9/28/201115



# Flammability summary

 

# According to previous information, AC5 and AC6

classification foreseen so far is 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 tbc tbc tbc tbc

Building codes Flammable Still under

review Flammable Still under

review

9/28/201116 

# Refrigerant Thermal Decomposition

 

# When exposed to sufficient energy sources all fluorinated refrigerants may decompose to produce

HF

 

### The amount of HF generated depends on the concentration of fluorinated refrigerant in contact with energy source, size and shape of energy source,

and time of contact



##  

# Testing of HF generation conducted with an actual vehicle (Hughes Associates) and in bench experiments (INERIS)

 

# INERIS results indicate the HF generated due to thermal decomposition is the same order of magnitude for AC5/AC6/R

- 1234yf

9/28/201117 

# Vehicle HF Concentrations Produced by Thermal Decomposition

 

# Concentration of HF at the breath level in the Interior of the Vehicle are considered in the risk


# assessment

 

# Hot Body near air inlet (700oC peak temperature)

 

## Represents extreme engine operation

 

# Hood seal removed allowing direct path to cabin air 

# intake, secondary failure

 

# Blower on outside air, high speed

 

# AC6 and R

- 1234yf are similar in terms of HF produced by thermal decomposition

 

# AC5 seems to produce somewhat more HF than R

1234yf

 

# Correlation to results at INERIS is under review

9/28/201118 9/28/2011



# Toxicology

 

# Provisional OELs have been assigned to AC5 and AC6 based on



# suite of test data

 

# Reviewed by Dr Lewandowski in CRP

 

# R

- 1234yf 500ppm

 

# AC5 800ppm

 

# AC6 900ppm

 

# R

- 134a 1000ppm

Science and Strategies for

Safe Environments19 

# Risk Assessment Methodology

 

## Structured approach carried out by same company as did

CRP

- 1234 FTA following same basic methodology

 

## Potential scenarios and inputs considered by MRB CRP team

 

## Failure modes considered

 

### Collision, Equipment Failure, Corrosion, Vehicle Fires, Service and Repair

 

## Considered exposures to

 

### Refrigerant, Fire, Decomposition products

 

## Included Hybrid Vehicles and Vehicles with Dual Evaporator 

## Systems

 

## Developed Fault Trees for AC5, AC6 and R

- 1234yf (due to updated inputs)

 

# Results for R

- 1234yf qualitatively similar to prior 

# analysis (i.e., risks of all refrigerants are well below other commonly accepted risks)

9/28/201120 

# Risk Assessment Results

Probabilities of Various Adverse events Compared to Probabilities of Events Associated with Vehicle Operation

- Related Refrigerant Leaks

Event Probability per vehicle per operating hour

Probability of being in a police reported vehicle collision 1 

## 5 x 10

- 5

Probability of dying during a 5000

- mile plane trip 2 

## 4 x 10

- 7

Probability of vehicle collision due to vehicle brake failure 3 

## 3 x 10

- 7

Probability of highway vehicle fire (any cause) 4 

## 1 x 10

- 7

Probability of an airbag

- related fatality associated with a vehicle collision 5 

## 2 x 10

- 10

Probability of vehicle occupant/former occupant experiencing HF exposure

above health based limits associated with R

- 1234yf ignition/ decomposition. 

## 6 x 10

- 14

Probability of vehicle occupant/former occupant experiencing HF exposure above health based limits associated with AC6 ignition/decomposition. 

## 6 x 10

- 14

Probability of vehicle occupant being exposed to an open flame due to R

1234 yf ignition 

## 9 x 10

- 15

Probability of vehicle occupant being exposed to an open flame due to AC 6 ignition 

## 7 x 10

- 17

Probability of AC service technician exposure to an open flame due to R

1234 yf ignition (per hour of vehicle service) 

## 8 x 10

- 21

Probability of AC service technician exposure to an open flame due to AC 6 ignition (per hour of vehicle service) 

## 5 x 10

- 22

9/28/201121 9/28/201122



### 0 5 10 15 20 25 30 35

0 5 10 15 20 25 Vehicle Speed ( Km/h)



### Time (min) 

# Vehicle Cool

- down Test Procedure

Ambient = 45 ° C Humidity = 45%

Solar Load = 1000 W/m 2



## Re

- Circulation

Idle23



# Cool

- down Performance 

# R134a vs. AC6 [Drop

- in Test]

0 10 20 30 40 50 60

0 5 10 15 20 25 Temp ( ° C)

Time (min)

R-134a - Avg Vent R-134a - Avg Front Breath

AC6 - Avg Vent AC6 - Avg Front Breath

# Seals AC5

Oil1 AC5

Oil2 AC6

Oil1 AC6

Oil2

EPDM std. 

## Ѵ Ѵ Ѵ Ѵ

EPDM opt. 

## Ѵ Ѵ Ѵ Ѵ

HNBR 1 

## Ѵ Ѵ Ѵ Ѵ

HNBR 2 

## Ѵ Ѵ Ѵ Ѵ

CR 

## Ѵ Ѵ Ѵ Ѵ 

# Compatibility S eals

Nearly all seal material show changes of their properties in tolerable

dimension

Several slight effects with oil (observable about color and IR

- spectra)

 No general problem with seal compatibility and AC5 / AC6hose AC5

Oil1 AC6

Oil1 AC5

Oil2 AC6

Oil2 AC5

Oil3 AC6

Oil3

PA type

PA type

-
PA type

- - -
PA type

PA type

IIR type

- - -
CR type

- - -
BIIR type

- - -
CR type

- - -

Rubber 

# Compatibility AC hoses

## Refrigerant Losses from hoses

Selective permeation Permeation rate @

90 ° C



## hose AC5 AC6 AC5 AC6

Veneer Type

Veneer Type

Rubber Type

Barrier Type

Barrier Type

Veneer Type

Barrier Type

-

Next Gen Veneer

Next Gen Veneer

-

Barrier

- -

Next Gen Veneer

Veneer [Dev]

# Compilation stability, electrical properties, 

# miscibility

Stability Electrical 

## properties Miscibility

AC5 AC6 AC5 & AC6 AC5 & AC6

Oil Type 1

- - Oil Type 2

- - Oil Type 328 9/28/2011



# Service and handling

 

# AC5 and AC6 are zeotropic refrigerants

 

# Method of production and delivery into system of each refrigerant in

- specification has been proven

 

# Handling effects on composition are understood

 

# Effect of composition on performance understood

 

# Work now underway on the effect on composition of practical recovery and reclaim techniques

 

# Refrigerant identifier technology being developed

 

## Proof of concept successful

 

## Work on field instrument in plan

 

# Further work planned to inform procedures for handling, recovery and recycle29 

# SAE Standards Assessment

Standard Number/Title Action Plan J639 Safety Standards for Motor Vehicle Refrigerant Vapor Compression Systems •N ew Fitting/Cautions on blend J1658 Alternate Refrigerant Consistency Criteria for Use in Mobile Air

- Conditioning Systems • Update and assign a new number

J2064 R

- 134a and R

- 1234yf Refrigerant Automotive Air

- Conditioning Hose and

Assemblies • No update needed right now

J2099 Standard of Purity for Recycled R

- 134a and R

- 1234yf or Use in Mobile Air

conditioning Systems • Simply update to reference new refrigerant

J2297 ULTRAVIOLET LEAK DETECTION: STABILITY AND COMPATIBILITY CRITERIA OF

FLUORESCENT REFRIGERANT LEAK DETECTION DYES FOR MOBILE R

- R

- 134a and R

R

- 1234yf ( HFO

- R

- 1234yf ) AIR

- CONDITIONING SYSTEMS • Simply update to reference new refrigerant

J2670 Stability and Compatibility Criteria for Additives and Flushing Materials Intended

for Use in R

- R

- 134a and R

- R

- 1234yf Vehicle Air

- Conditioning Systems • Simply update to reference new refrigerant J2772 Measurement of Passenger Compartment Refrigerant Concentrations under system refrigerant leakage conditions • Simply update to reference new refrigerant J2773 Standard for Refrigerant Risk Analysis for Mobile Air Conditioning Systems • Simply update to reference new refrigerant

J2842 R

- 1234yf and R744 Design Criteria and Certification for OEM Mobile Air Conditioning Evaporator and Service Replacements • Simply update to reference new refrigerant

J2843 R

- 1234yf Recovery/Recycling/Recharging Equipment for Flammable Refrigerants

for Mobile Air

- Conditioning Systems • New standard under development

J2844 R

- 1234yf New Refrigerant Purity and Container Requirements Used in Mobile Air

Conditioning Systems • New standard under development

J2845 Technician Training for Safe Service and Containment of Refrigerants Used in Mobile A/C Systems (R

- 744, and R

- 1234yf ) • New standard under development

J2851 R

- 1234yf Refrigerant Recovery Equipment for Mobile Automotive Air

- Conditioning Systems • New standard under development

J2888 R

- 1234yf Service Hose, Fittings and Couplers for Mobile Refrigerant Systems Service Equipment • Simply update to reference new refrigerant J2911 Certification Requirements For Mobile Air Conditioning System Components, Service Equipment, and Service Technicians to Meet SAE J Standards • Simply update to reference new refrigerant

J2912 R

- 1234yf Refrigerant Identification Equipment for Use with Mobile Air Conditioning Systems • New standard under development

9/28/201130



# Work Plan to Finish

 

# Work to reach decision point on key open issues

 

## Service & handling

 

## Estimate 3

- 4 months to prove technique for workshop recovery
and re

- use

 

## Performance optimisation

 

## Development of optimal evaporator configuration

 

## Material/Oil optimisation

 

## Durability testing for compressor

 

## Final safety studies

 

## Consider AC6 potential in a heat pump system

 

# Goal to finish technical work no later than mid 2012

 

## Non

- Technical issues are not addressed inside the CRP

 

# SNAP submission with CRP support

 

# Engagement of new team members are welcomed

 

## Meeting open for potential new OEM sponsors to be held on Thursday afternoon

9/28/201131



# Conclusions

 

## AC5 and AC6 have been extensively tested via a rigorous CRP

 

## AC5 matches the LCCP performance of R

- 1234yf

 

## AC6 needs some further improvement in energy efficiency

 

## Reduced flammability of AC6 offers potential benefits; AC5 is comparable to R

- 1234yf in terms of flammability

 

## Systems components, lubricants and hoses are available for AC5 and AC6 systems

 

## Project has made remarkable progress in 7 months; some further work still to complete in order to allow final selection of technically preferred fluid

 

## Compatibility with electrical compressors provide an 

## opportunity for these fluids for use with heat pump systems in

electric vehicles

9/28/2011 

## Either AC5 or AC6 offer options as low GWP refrigerants for MAC systems32



# MRB CRP Sponsors

9/28/2011