The paper presents an experimental analysis of the performance of a prototype air conditioning system based on transcritical operation with R744 as the refrigerant. A comparative analysis of the performance of three systems is also presented: two R744 (with back pressure and manual expansion valves) and R134a with a fixed area orifice tube.Results show that there is an optimal setting of the back pressure valve in cycling conditions that maximizes COP for the R744 system. That is very important because the system operates most of the time in cycling mode, where there is excessive capacity, and the objective is to maximize COP. Furthermore, it is shown that those values follow the same relation as developed for non-cycling operation.


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    Title :

    Clutch Cycling Mode of Compressor Capacity Control of Transcritical R744 Systems Compared to R134a Systems


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    Vehicle Thermal Management Systems Conference & Exposition ; 2005



    Publication date :

    2005-05-10




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Clutch Cycling Mode of Compressor Capacity Control of Transcritical R744 Systems Compared to R134a Systems

    McEnaney, R. / Hrnjak, P. / Society of Automotive Engineers | British Library Conference Proceedings | 2005


    Clutch cycling mode of compressor capacity control of transcritical R744 systems compared to R134a systems

    McEnaney,R. / Hrnjak,P. / Univ.of Illinois at Urbana-Champaign,US | Automotive engineering | 2005


    Control Strategies for Transcritical R744 Systems

    McEnaney, R. P. / Hrnjak, P. S. / Society of Automotive Engineers | British Library Conference Proceedings | 2000


    Control Strategies for Transcritical R744 Systems

    Hrnjak, P. S. / McEnaney, R. P. | SAE Technical Papers | 2000


    Control strategies for transcritical R744 systems

    McEnaney,R.P. / Hrnjak,P.S. / Univ.of Illinois,Chicago,US | Automotive engineering | 2000