Steady State and Transient Simulation of R744 HVAC ... · Steady State and Transient Simulation of R744 HVAC-Systems and its Application on Hybrid Vehicles J. Hager 1)– G. Lang

Steady State and Transient Simulation of R744 HVAC-

Systems and its Application on Hybrid Vehicles

J. Hager 1) – G. Lang 2) – R. Rieberer 3)

1) MAGNA POWERTRAIN - Engineering Center Steyr, St. Valentin, Austria2) Kompetenzzentrum – Das virtuelle Fahrzeug Forschungsgesellschaft, Graz, Austria

3) Graz University of Technology, Institute of Thermal Engineering, Graz, Austria

2

Outline

hIntroductionhSteady State OperationhTransient Operating ConditionshSimulation Set Up for Vehicle Air ConditioninghHybrid Vehicle Simulation ResultshSummary

3

Outline


4

Driving Cycles

0

20

40

60

80

100

120

140

Velo

city

[km

/h]

0

2040

6080

100120

140

Velo

city

[km

/h]

020406080

100120140

0 200 400 600 800 1000 1200Time [s]

Velo

city

[km

/h]

NEDC

SC03

Pull Down

Acceleration 0,53 m/s²~ 150 RPM/s

Acceleration 0,50 m/s²~ 140 RPM/s

Acceleration 0 m/s²0 RPM/s

5

Outline


6

Climatic Chamber Test Stand

Air temperature range -20 … +40 °CRelative humidity 20 … 80 %

Flow wind tunnel 1: 60 … 500 m³/hFlow wind tunnel 2: 600 … 4000 m³/h

7

Evaporator Capacity and COP

0

1

2

3

4

5

6

400 600 800 1000 1200 1400Speed / 1/min

Cap

acity

/ kW

560 kg/h300 kg/h

t_amb =25°Cx_amb = 13 g/kgmf_A_EHX = 2000 kg/h

Error Bars: 5%

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

400 600 800 1000 1200 1400

Speed / 1/min

CO

P

560 kg/h300 kg/h

t_amb =25°Cx_amb = 13 g/kgmf_A_EHX = 2000 kg/h

Error Bars: 5%

Steady stateevaporator capacitymeasured and simulated

Steady stateCOP

measured and simulated

8

Outline


9

Start-up Measurement

250

300

350

400

450

500

550

0 20 40 60 80 100 120 140 160 180

Time [s]

Enth

alpy

[kJ/

kg]

h-Compr-out h-Compr-inh-GC-in h-GC-outh-SLHX-hp-out h-SLHX-lp-in

0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180

Time [s]

Pres

sure

[bar

]

0

200

400

600

800

1000

1200

Com

pr S

peed

[RPM

]

p-compr-hp p-compr-lpn-compr-measured

10

Influence of Thermal Capcities

50

1501.

2

1.4

1.6

2.0

1.8

20

30

40

50

60

70

80

90

100

110

260 310 360 410 460 510 560Enthalpy [kJ/kg]

Pres

sure

[bar

]

Compressor

Gas CoolerSLHX

SLHXEvaporator

Thermal Capacities

11

Start-up Simulation of Gas Cooler

0

1

2

3

4

5

6

7

0 20 40 60 80 100 120 140 160 180

Time [s]

Cap

acity

, Pow

er [k

W] P-compr-measured

Q-GC-measuredP-compr-quasiQ-GC-quasiP-compr-massQ-GC-mass

12

Start-up Simulation of Evaporator

0

1

2

3

4

5

6

0 20 40 60 80 100 120 140 160 180

Time [s]

Cap

acity

, Pow

er [k

W] P-compr-measured

Q-evap-measuredP-compr-quasiQ-evap-quasiP-compr-massQ-evap-mass

13

Start-up – Simulation Evaporator Air Out Temperature

0

5

10

15

20

25

30

35

0 20 40 60 80 100 120 140 160 180

Time [s]

Tem

pera

ture

[°C

]

T-evap-air-out-measuredT-evap-air-out-quasiT-evap-air-out-airMassT-evap-air-out-mass

14

Comparison Measurement Quasi Steady State Simulation

15

Air Side Temperatures Evaporator

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Time [s]

Tem

pera

ture

[°C

] T-evap-air-out-measured T-evap-air-out-quasi

T-evap-air-out-mass T-evap-air-in

16

Outline


17

Simulation Environment Hybrid Vehicle

KULI CRUISE

Drivervr va

Va ... Actual Velocity

nE ... Engine SpeedGear

PFriction, PConsumer

Water Pump, Oil Pump,

PTC, A/C Compressor, Fans

nE, BMEP, va

va

Fuel Consumption

EmissionsCabin Temperature

Load Signal

-20

-10

0

10

20

30

0 5 10 15 20 25 30 35 40 45Time [min]

Tem

pera

ture

[°C

]

-20°C

-7°C

0°C

KULIKULI CRUISECRUISE

Drivervr va

Va ... Actual Velocity

nE ... Engine SpeedGear

PFriction, PConsumer

Water Pump, Oil Pump,

PTC, A/C Compressor, Fans

nE, BMEP, va

va

Fuel Consumption

EmissionsCabin Temperature

Load Signal

-20

-10

0

10

20

30

0 5 10 15 20 25 30 35 40 45Time [min]

Tem

pera

ture

[°C

]

-20°C

-7°C

0°C

18

Simulation Model

HVAC Module Passenger Compartment

Engine

Engine Cooling

19

Simulation Model – Fluid CircuitsInfluence of Compressor Driving Power on Engine

Operating Point

Refrigerant Circuit

Influence of Compressor Driving Power on EngineOperating Point

Refrigerant Circuit

20

Air Conditioning of Hybrid Vehicle

hStart / stop driving conditionshElectrical driven compressorhAir conditioning comfort equal or better

compared to conventional vehiclehR744 circuit with cooling and heating mode

(heat pump)hOptimization of fuel consumption for air

conditioning

21

Vehicle DataFront wheel driven passenger carVehicle mass = 1467 kg

Conventional HybridCombustion engine 4 cylinder diesel

supercharged3 cylinder diesel supercharged

Displacement [l] 2 1.2

Power ICE [kW] 80 57

Electric motor [kW] - 10

Generator [kW] - 10

Storage capacity [kWh] - 3.36

22

Outline


23

Fuel Consumption

Fuel Consumption / NEDC (26°C)compared to Baseline Vehicle w/o AC

-20

-10

0

10

20

Baseline w/ AC Hybrid w/ AC Hybrid w/o AC% c

hang

e

24

Accumulated Fuel Consumption NEDC

0

100

200

300

400

500

600

0 5 10 15 20Time [min]

acc.

Fue

l Mas

s [g

] Basis w/o AC

Basisfahrzeug + AC

0

100

200

300

400

500

600

0 5 10 15 20

Time [min]

acc.

Fue

l Mas

s [g

] Hybrid w/ AC

Hybrid w/o AC

Hybrid Vehicle

ICE Vehicle

25

Hybrid – State of Charge

50

60

70

80

90

0 5 10 15 20

Time [min]

SO

C [%

]

Hybrid Basis

Hybrid w/ AC

26

Outline


27

SummaryhSteady state and transient operating

conditions were studied on an AC test standhTest results were used to verify numerical

simulation methodshFull transient simulation means a high effort

for numerical simulationhFor many operating conditions it is sufficient to

consider thermal capacitieshA co-simulation method was used to optimize

the fuel consumption of the AC of a hybrid vehicle

Documents

Steady State and Transient Simulation of R744 HVAC ... · Steady State and Transient Simulation of R744 HVAC-Systems and its Application on Hybrid Vehicles J. Hager 1)– G. Lang