For a vehicle air-conditioning system Total Equivalent Warming Impact (TEWI) evaluations (simulation results) emphasize the combined environmental effect of the direct emission of greenhouse gases with indirect effects of CO2 emissions from energy burning by the equipment using these fluids as refrigerants. The direct effect of refrigerant emissions from HFC-based automobile air-conditioners are significant part of the TEWI. While not perfect, the environmental evaluation is a detailed analysis incorporating various ambient temperatures profiles, humidity in the considered climate region, cooling demand for a medium sized vehicle as function of the temperature for different humidity, cooling capacities and efficiencies of a R134a/R744 system as a function of air temperature and humidity, extra fuel consumption as related to additional crankshaft engine power at various driving cycles. For an air-conditioner an optimistic scenario and in a pesimistic scenario R134a refrigerant emissions are assumed over the entire life cycle of the automobile. For the considered medium sized vehicle with determined user profiles (different climate regions, NEDC-cycle, mix of US-city- and EPA-Highway-cycle (55 %/45 %); 15 % Idle operation) and for the regarded emission scenarios, a reduction of global warming by phasing out the actual in use refrigerant HFC-134a is possible. This environmental benefit is available without reducing thermal comfort of occupants in the compartment and customers satisfaction. The energy consumption for air conditioning driving at steady state conditions is estimated in the same range or lower for CO2 systems compared to state of the art HFC systems.


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    Title :

    An environmental evaluation of an automobile air conditioning system with CO2 verses HFC-134A as refrigerant


    Contributors:
    Wertenbach, J. (author) / Caesar, R. (author)


    Publication date :

    1998


    Size :

    10 Seiten, 9 Bilder, 7 Tabellen, 5 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English