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R744 Parallel Compression Cycle for Automotive Climate Control
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 28, 2017 by SAE International in United States
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The natural refrigerant, R744 (CO2), remains a viable solution to replace the high GWP refrigerant R134a which is to be phased out in light-duty vehicles in EU and US market. In this study, thermodynamic analysis is performed on a R744 parallel compression system to evaluate its potential in automotive climate control. The model adopts a correlation of isentropic efficiency as a function of compression ratio based on a prototype R744 MAC compressor and accounts for the operating limits defined in the latest DIN specifications. Optimization is run over typical MAC operating conditions which covers both transcritical and subcritical domain. Comparing to the conventional single compression cycle, effectiveness of parallel compression is found most pronounced in low evaporating temperature and high ambient conditions, with up to 21% increase in COP and 5.3 bar reduction in discharge pressure observed over the considered parametric range. Correlations of the optimal discharge pressure and intermediate pressure are developed as a function of evaporating temperature and gas cooler exit temperature using linear regression, which facilitate utilization of dynamic control towards optimal operating efficiency. Finally, various compressor designs are discussed for possible implementation of parallel compression in a R744 MAC or heat pump system. Consistent with the findings in commercial refrigeration, parallel compression holds promise from performance perspective to promote use of R744 technology in warm regions for automotive climate control.
CitationHe, J., Johnston, B., Dhar, D., and Lohmeyer, L., "R744 Parallel Compression Cycle for Automotive Climate Control," SAE Technical Paper 2017-01-0175, 2017, https://doi.org/10.4271/2017-01-0175.
- Juul , A. Retailers Ensure Sustainable Technology Update Presentation at ATMOsphere Asia 2015 February 2015
- Funder-Kristensen , T. Barriers and Opportunities for Selection of Best Low GWP Technologies Presentation at ATMOsphere Europe 2015 March 2015
- DENSO Global DENSO Develops World’s First Passenger Vehicle Air Conditioning System Using an Ejector http://www.globaldenso.com/en/newsreleases/090519-01.html
- Sarkar , J. , and Agrawal , N. , Performance Optimization of Transcritical CO 2 Cycle with Parallel Compression Economization International Journal of Thermal Sciences 49 838 843 2010 10.1016/j.ijthermalsci.2009.12.001
- Chesi , A. , Esposito , F. , Ferrara , G. , and L. Ferrari Experimental Analysis of R744 Parallel Compression Cycle Applied Energy 135 274 285 2014 10.1016/j.apenergy.2014.08.087
- He. , J. , Dhar , D. , Johnston , W. , and Lohmeyer , L. Dynamically Controlled Vehicle Cooling and Heating System Operable in Multi-Compression Cycles US Patent Application 14/823667 August 11 2015
- Försterling , S. , Tegethoff , W. , and Köhler , J. Theoretical and Experimental Investigation on Carbon Dioxide Compressors for Mobile Air Conditioning Systems and Transport Refrigeration International Refrigeration and Air Conditioning Conference Paper 585 2002 http://docs.lib.purdue.edu/iracc/585/
- Hirano , T. , and Shigeoka , T. The Scroll Compressor with Variable Capacity Control Mechanism for Automotive Air Conditioner International Compressor Engineering Conference Paper 697 1990 http://docs.lib.purdue.edu/icec/697/