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Least-Enthalpy Based Control of Cabin Air Recirculation
Technical Paper
2015-01-0372
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The vehicle air-conditioning system has significant impact on fuel economy and range of electric vehicles. Improving the fuel economy of vehicles therefore demand for energy efficient climate control systems. Also the emissions regulations motivate the reduced use of fuel for vehicle's cabin climate control. Solar heat gain of the passenger compartment by greenhouse effect is generally treated as the peak thermal load of the climate control system. Although the use of advanced glazing is considered first to reduce solar heat gain other means such as ventilation of parked car and recirculation of cabin air also have impetus for reducing the climate control loads. However experimental based recirculation control strategies may lead to - 1) increased humidity levels, increasing the risk of windshield fogging, especially during cabin heating operation, 2) unpleasant odors due to biological aerosols and harmful volatile organic compounds and 3) insufficient oxygen and high CO2 levels inside the cabin. The analytical method is proposed to determine compressor work for a given cabin cooling requirement defined by the evaporator outlet air temperature and a mixing ratio and for known coefficient of performance of the compressor, the mass flow of evaporator air and the enthalpies of air from outside and inside of the passenger compartment. The compressor work is obtained as a linear function of mixing ratio for the unsaturated evaporator outlet air and a quadratic function for the saturated evaporator outlet air. The solution of these expressions is found to re-emphasize the fact that the least-enthalpy of air at the evaporator inlet requires minimum compressor work for cooling of the air. The applicability of a proposed method is demonstrated by using the closed loop simulation results obtained with the help of a thermal simulation tool - eThermal under various vehicle operating conditions. Particularly, reduced compressor power for cabin cooling while maintaining thermal comfort and safety of the vehicle occupants is observed. Correlations for calculating coefficient of performance of a compressor are also provided.
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Citation
Kakade, R., "Least-Enthalpy Based Control of Cabin Air Recirculation," SAE Technical Paper 2015-01-0372, 2015, https://doi.org/10.4271/2015-01-0372.Also In
References
- State Transportation Statistics United States Bureau of Transportation Statistics http://www.rita.dot.gov/bts/ September 2014
- Farrington , R. and Rugh , J. Impact of Vehicle Air- Conditioning on Fuel Economy, Tailpipe Emissions, and Electric Vehicle Range National Renewable Energy Laboratory September 2000
- Fayazbakhsh , M. and Bahrami , M. Comprehensive Modeling of Vehicle Air Conditioning Loads Using Heat Balance Method SAE Technical Paper 2013-01-1507 2013 10.4271/2013-01-1507
- Fischer , S.K. Comparison of Global Warming Impacts of Automobile Air-Conditioning Concepts 1995 International CFC and Halons Alternative Conference Washington, D.C., USA 1995
- Atkinson , W. Designing Mobile Air-Conditioning Systems to Provide Occupant Comfort SAE Technical Paper 2000-01-1273 2000 10.4271/2000-01-1273
- Farrington , R. , Anderson , R. , Blake , D. , Burch , S. et al. Challenges and Potential Solutions for Reducing Climate Control Loads in Conventional and Hybrid Vehicles National Renewable Energy Laboratory Golden, CO, USA 1999
- Donovan , P. and Manning , J. Strategy for Efficient Automotive Climate Control SAE Technical Paper 2007-01-1190 2007 10.4271/2007-01-1190
- Brown , J. , Yana-Motta , S. and Domanski , P. Comparative Analysis of Automotive Air Conditioning Systems Operating with CO 2 and R134a Intl. J. Refrigeration 25 19 32 2002 10.1016/S0140-7007(01)00011-1
- Tumas , T. , Maniam , B. , Mahajan , M. , Anand , G. et al. e- Thermal: A Vehicle-Level HVAC/PTC Simulation Tool SAE Technical Paper 2004-01-1510 2004 10.4271/2004-01-1510
- Anand , G. , Mahajan , M. , Jain , N. , Maniam , B. et al. e-Thermal: Automobile Air-Conditioning Module SAE Technical Paper 2004-01-1509 2004 10.4271/2004-01-1509
- Ye , T. A Multidisciplinary Numerical Modeling Tool Integrating CFD and Thermal System Simulation for Automotive HVAC System Design SAE Technical Paper 2012-01-0644 2012 10.4271/2012-01-0644
- Cengel , Y. Heat Transfer: A Practical Approach Second McGraw-Hill 2003 9780072458930
- Cengel Y. and Boles , M. Thermodynamics: An Engineering Approach Fifth McGraw-Hill 2006 9780072884951
- Forrest , W. and Bhatti , M. Energy Efficient Automotive Air Conditioning System SAE Technical Paper 2002-01-0229 2002 10.4271/2002-01-0229
- Koutsoyiannis , D. Clausius-Clapeyron Equation and Saturation Vapour Pressure: Simple Theory Reconciled with Practice Eur. J. Phys. 33 295 305 2012 10.1088/0143-0807/33/2/295
- Huber , M.L. and McLinden , M.O. Thermodynamic Properties of R134a (1,1,1,2-tetrafluroethane) International Refrigeration and Air Conditioning Conference, Paper 184 1992 http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1183&context=iracc September 2014