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Expansion Devices for R-744 MAC Units
ISSN: 0148-7191, e-ISSN: 2688-3627
Published May 10, 2005 by SAE International in United States
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In mobile R-744 A/C units mechanical expansion devices (e.g. orifice tubes) or electronic valves (e.g. PWM-valves) can be used. Besides the costs, aspects like coefficient of performance (COP), cooling capacity or control behavior - especially for extreme conditions - influence the choice of the valve type. This paper will present a comparison between an ideal electronic valve and a two stage mechanical orifice tube under full load and part load conditions. The influence of the expansion valve on COP and cooling capacity in different ambient conditions can be sufficiently described with steady-state simulations. The simulation tools used for this work are based on Modelica/Dymola. The simulation results show that for European climate conditions the use of two-stage orifices might increase fuel consumption.
CitationLemke, N., Tegethoff, W., Köhler, J., and Horstmann, P., "Expansion Devices for R-744 MAC Units," SAE Technical Paper 2005-01-2041, 2005, https://doi.org/10.4271/2005-01-2041.
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