Characteristic Evaluation on the Cooling Performance of an Electrical Air Conditioning System Using R744 for a Fuel Cell Electric Vehicle
Abstract
:1. Introduction
2. Experimental Setup and Data
2.1. Test Setup
Components | Specifications | |
---|---|---|
Stack capacity of the fuel cell electric vehicle | Capacity (kW) | 80.0 |
Evaporator (Interior heat exchanger) | Capacity (kW) | 5.0 at 4 m3/min and 6000 rpm |
Type, core size (mm3) | Multi-flow type, W 250 × H 260 × D 35 | |
Gas cooler (Exterior heat exchanger) | capacity (kW) | 7.5 at 4 m/s, 35 °C and 6000 rpm |
Type, core size (mm3) | Multi-flow type, W 630 × H 375 × D 16 | |
Internal heat exchanger | Capacity (kW) | 0.5~1.5 at 2 m/s and 6000 rpm |
Type, length (mm) | Co-axial, 750~1250 | |
Compressor | Type | Electric driven compressor |
Displacement (cc/rev) | 7.5 | |
Expansion valve | Type | Electronic control (PWM) |
Flow rate (kg/h) | 50~250 | |
Accumulator | Pressure (bar) | Max. 125 at 90 °C |
Volume (cc) | 550 |
Components | Conditions |
---|---|
Compressor speed (RPM) | 3000, 4000, 5000, 6000 |
Vgas cooler, in (m/s) | 2.0, 4.0 |
Tgas cooler, in (°C) | 27.0, 35.0, 42.0 |
Rhevaporator (%) | 50.0 |
Tevaporator, in (°C) | 27.0, 35.0, 42.0 |
Qevaporator, in (m3/min) | 4.0, 7.0 |
Items | Accuracy |
---|---|
Thermocouples (T-type) | ±0.1 °C |
Pressure gage (Sensors, PI3H) | ±0.1% (Max. 250 bar) |
Mass flow meter (Coriolis type) | ±0.15%, Max. 680 kg/h |
Data logger (Gantner) | E. Gate IP (V3) (2.93W @ 12.06 V) |
Cooling capacity | 4.5% |
Cooling COP | 5.8% |
2.2. Data Reduction
3. Results and Discussion
4. Conclusions
- (1)
- The cooling COP and the cooling capacity increased by 30.3% up to 2.5 and 36.8% up to 6.4 kW, respectively, with the rise of the gas cooler inlet pressure from 92.0 bar to 102.0 bar at the gas cooler inlet temperature of 35.0 °C and the compressor speed of 4000 rev/min.
- (2)
- The cooling capacity increased with rise of the compressor speed but the cooling COP was reduced because the compressor work increased due to the increased compression ratio and specific volume at the compressor inlet.
- (3)
- At the gas cooler inlet pressure of 90.0 bar, the cooling COP and the cooling capacity decreased by 55.6% and 55.1%, respectively, with the rise of the gas cooler air inlet temperature from 27 °C to 42 °C due to the decreased heat transfer efficiency of the gas cooler.
- (4)
- Under extremely hot weather conditions over 35.0 °C, the cooling capacity of the tested system was sufficient, over 5.0 kW, at the compressor speed over 4500 rev/min.
- (5)
- The cooling COP of the electrical air conditioning system using R744 was on average 24.3% higher than that using R-134a at all compressor speeds.
Nomenclature
COP | Coefficient of performance |
FEM | Front end module |
h | Enthalpy (kJ/kg) |
Mass flow rate (kg/h) | |
Heat transfer rate (W) | |
RPM | Revolution per minute (rev/min) |
Rh | Relative humidity (%) |
T | Temperature (°C) |
V | Velocity (m/s) |
Subscripts
A | air |
comp | compressor |
in | inlet |
out | outlet |
p | pressure |
ref | refrigerant |
Acknowledgments
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Lee, M.-Y.; Lee, H.-S.; Won, H.-P. Characteristic Evaluation on the Cooling Performance of an Electrical Air Conditioning System Using R744 for a Fuel Cell Electric Vehicle. Energies 2012, 5, 1371-1383. https://doi.org/10.3390/en5051371
Lee M-Y, Lee H-S, Won H-P. Characteristic Evaluation on the Cooling Performance of an Electrical Air Conditioning System Using R744 for a Fuel Cell Electric Vehicle. Energies. 2012; 5(5):1371-1383. https://doi.org/10.3390/en5051371
Chicago/Turabian StyleLee, Moo-Yeon, Ho-Seong Lee, and Hong-Phil Won. 2012. "Characteristic Evaluation on the Cooling Performance of an Electrical Air Conditioning System Using R744 for a Fuel Cell Electric Vehicle" Energies 5, no. 5: 1371-1383. https://doi.org/10.3390/en5051371