R-152a for Mobile Air Conditioning · PDF fileR-152a for Mobile Air Conditioning ... R-134a Molecular Weight = 66 ASHRAE A2 – Mildly Flammable Similar Materials Compatibility GWP

WARNING: HFC-152a is a flammable refrigerant and sh ould not be used in systems unless specifically designe d for its use. MAC Summit - 2005

R-152afor Mobile Air Conditioning

Mobile Air Conditioning Summit 2005California Air Resources Board

United States Environmental Protection AgencySacramento, California

March 15-16, 2005

James A. Baker

Delphi Corporation


Refrigerant Change Would Reduce Climate Impact by 9 4%(Combined effect of reduced GWP + reduced refrigera nt charge)

[94% Savings Does Not Include Possible Energy Savin gs]

F F

H C C F

H F

Molecular Weight = 102

ASHRAE A1 – Non-Flammable

GWP = 1300

R-134a

Molecular Weight = 66

ASHRAE A2 – Mildly Flammable

Similar Materials Compatibility

GWP = 120

H H

H C C F

H F

R-152a

R-152a - Chemically Very Similar to R-134a,But, Environmentally Very Different


Mobile A/C System Types

� Direct System (Primary Loop) (Heat exchanger containing refrigerant in passenger cabin )

– Single Evaporator System – Automobiles– Dual Evaporator System – SUV’s, Vans, etc.

� Indirect System (Secondary Loop) (Refrigerant contained within engine compartment )

– Single Cooler System – Automobiles– Multiple Cooler Systems – All Passenger Vehicles


Front CoolerFront Pump

Reservoir

Coolant System

RearCooler

RearPump

Refrigerant System

Condenser

Ex. Device

AccumulatorVariable Displacement

Compressor

System Description

Mobile A/C System Types

Chiller


R-152a Mobile A/C with Directed ReliefSafety System

Mahmoud Ghodbane, Ph.D.James A. Baker

Delphi

Stephen O. Andersen, Ph.D.U. S. EPA

Summer 2003


OverboardDischarge,

e.g., toWheel Wells

Compressor

Expansion Device

EvaporatorCondenser

R/D

R-152a Sensor in HVAC Case

Relief Device

Relief Device

Direct Expansion R-152a Mobile A/C System

System Description


Performance Comparison

Ion A/C Cool Down Performance Comparison @ 100 0F x 40% R.H. Ambient (38 0C x 40% R.H.)

30

50

70

90

110

130

150

0 10 20 30 40 50 60 70

Time (min.)

Tem

pera

ture

(0 F

)

Average Breath

Average Discharge

R-152a R-134a

Soak Temperature

-1

66

54

43

32

21

10

(0C)

40 kph (Recir. Air)

C.T.(Recir. Air)

40 kph (Recir. Air)

50 kph (Recir. Air)

100 kph (Outside Air) Idle

(Recir. Air)



Direct Expansion R-152a Mobile A/C SystemEfficiency

Coefficient of Performance Comparison

100 0F x 40% R.H. (38 0C x 40% R.H.)

0

0.5

1

1.5

2

2.5

3

3.5

4

30 mph (48 kph) 50 mph (80 kph) 70 mph (113 kph) Idle

Vehicle Speed

CO

P

R134a R152a

+20% +22%

+9%

+7%


� R-152a Offers

− Outstanding environmental advantages

− Better cooling performance than R-134a

− Better energy efficiency than R-134a

− Relative ease of industry conversion

R-152a Merits Consideration by VehicleMakers for Future A/C Systems

Conclusions


WARNING: HFC-152a is a flammable refrigerant and sh ould not be used in systems unless specifically designe d for its use.

Secondary Loop R-152a Mobile A/CSystem

Mahmoud Ghodbane, Ph.D.Delphi

Hans FernqvistVolvo

Summer 2003

CARS CARS CARS CARS


Test Vehicle

� Sport utility vehicle (SUV) with front and rear A/C system

� Vehicle tested first with O.E. R-134a system, t hen equipped & tested with R-152a Secondary Loop System in the same tunnel

� Same condenser and evaporator air flows for bot h systems

� Refrigerant charge: 2.87 lb (1302 g) for R-134a baseline system versus 1.30 lb (590 g) for R-152a Secondary Loop system

Secondary Loop R-152a Mobile A/C System



Front CoolerFront Pump

Reservoir

Coolant System

Chiller

RearCooler

RearPump

Refrigerant System

Condenser

Ex. Device

AccumulatorVariable Displacement

Compressor


32

42

52

62

72

82

92

102

112

122

132

0 5 10 15 20 25 30 35 40 45 50

(°F)

0

10

20

30

40

50

60

(°C)

XC90 A/C Cool-Down Performance Comparison@ 100°F x 40% R.H. (38°C x 40% R.H.)

40 kph

City Traffic

40 kph

50 kph

100 kph

Idle

Time (min.)

Average Breath

Average A/C Discharge

Soak Temperature

R-134a Baseline R-152a Sec. Loop

Performance ComparisonSecondary Loop R-152a Mobile A/C System


32

50

68

86

104

122

140

0 10 20 30 40 50

(°F)

0

10

20

30

40

50

60

(°C)

40 kph

City Traffic

40 kph

50 kph

100 kph

Idle

XC90 A/C Cool-Down Performance Comparison@ 86°F x 60% R.H. (30°C x 60% R.H.)

Time (min.)

Soak Temperature

Average Breath

Average A/C Discharge

R-134a Baseline R-152a Sec. Loop

Performance ComparisonSecondary Loop R-152a Mobile A/C System


Alternative Refrigerant Systems SAE Phoenix Forum C omfort Evaluation

Comfort Ride Rating Phoenix 2003

(Average of Two Days Ride)

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

Rat

ing

City Traffic Road Speed

ToyotaCelsior

SaturnIon

AlfaRomeo

JaguarS-Type

2002LibertySport

CadillacCST

VolvoS60

VolvoXC 90

PontiacGrand

Prix

BMW 3Series

HondaCivic

NissanCube

DelphiR152a

DelphiCO2

Comfortable

Delphi R-152a Sec. Loop

Rating Scale: (1) Sweaty (2) Hot (3) Warm (4) Slightly Warm (5) Comfortable (6) Slightly Cool

Comfort Ride Rating Phoenix 2003

(Average of Two Days Ride)

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

Rat

ing

City Traffic Road Speed

ToyotaCelsior

SaturnIon

AlfaRomeo

JaguarS-Type

2002LibertySport

CadillacCST

VolvoS60

VolvoXC 90

PontiacGrand

Prix

BMW 3Series

HondaCivic

NissanCube

DirectR152a

CO2

Comfortable

Rating Scale: (1) Sweaty (2) Hot (3) Warm (4)Slightly Warm (5) Comfortable (6) Slightly Cool

CO2 CO2 CO2 CO2 CO2S. L.R152a

Prod.R134a

Prod.R134a

Prod.R134a

Prod.R134a


Environmental

Performance

Energy

Mass

Packaging

Reliability

Cost

Versus R-134a

++0 *

- (5 to 10%)

- - - -0 -

* In city traffic and Idle, the advantage goes to S econdary Loop

Environmental

Performance

Energy

Mass

Packaging

Reliability

Cost

++Versus R-134a

0 * - (5 to 10%)

- -++0/+

Summary of Secondary Loop versus Current R-134a Sy stem

Front System Front & Rear System



Conclusions

General BenefitsGeneral Benefits

� Comparable Cooling Performance to Direct R-134a Systems

� Improves City Traffic & Idle Cooling Performanc e

� Enables Maintenance of Comfort with Compressor off (Idle-Stop)(Rail & Border Crossing, Compressor De-Stroking at WOT & Idle, Hybrid Vehicles at Stop, etc…) Potential for Energy Savings

� Potential for Targeted Cooling (e.g., Seats)

� Reduces Refrigerant Charge & Leakage

� Refrigerant System Noise Reduction - Front and Rear

� Eliminates refrigerant mal-distribution (Coolant exhibits more uniformtemperature distribution than refrigerant)



Vehicles with Rear HVAC Systems

� Eliminates Entire Rear Refrigerant System

� Reduces Rear HVAC Case Size (Rear Single Heat Exchanger)

� Cost Savings over Current System !

Challenges

� Chiller / Pump Packaging Underhood

� Small A/C Energy Penalty (5 to 10%)

� Small Mass Penalty (3-4 kg)

Conclusions


Note: No technical barriers exist that would prevent the rapid commercialization of R-152a secondary loop sy stems


� R-152a Offers

− Outstanding environmental advantages

− At least equal cooling performance to R-134a

− Comparable energy efficiency to R-134a

− Relative ease of industry conversion

R-152a Merits Consideration by VehicleMakers for Future A/C Systems

Conclusions


R-152a Secondary Loop Systems Offer

� the best combination of environmental performance, lowest cost, and lowest technical & reliability risk of any alternative to R-134a proposed to date. Cha nge would be transparent to consumers

� the ability to use current R-134a component technologies, allowing smoother, lower cost transition from R-134a

The “Bottom Line”

� the safest alternative to R-134a proposed to date


“There is currently no significant differencebetween technically achievable LCCP of

HFC-152a and CO2 systems.”

Summary for Policymakers (SPM) January 11, 2005

IPCC/TEAP Special Report on Safeguarding the Ozone Layer andthe Global Climate System: Issues Related to Hydrof luorocarbonsAnd Perfluorocarbons


What is Needed for R-152a Success (Those Who Can Make It Happen )

• Regulatory Support� European Union (Retain GWP 150)� California Air Resources Board� US EPA SNAP Program

• Vehicle Makers’ Support

• Chemical Industry Support� Supply of R-152a


“The Future is

in the Hands of Those

Who Can Make it Happen”

Documents

R-152a for Mobile Air Conditioning · PDF fileR-152a for Mobile Air Conditioning ... R-134a Molecular Weight = 66 ASHRAE A2 – Mildly Flammable Similar Materials Compatibility GWP