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Hittade 4 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. HFC Mixtures as Replacement for HCFC-22 in Large-Scale Heat Pumps and Chillers

    Författare :Cecilia Gabrielii; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; R404A; R143a; R125; performance; R134a; R32; replacement; zeotropic HFC mixtures; simulations; design; measurements; chiller; R407C; condenser evaporator; screening; optimization; heat pump; R22;

    Sammanfattning : Replacement of the conventional refrigerant HCFC-22 (R22) is one of the urgent issues to be solved within the scheduled time-frame of the international regulation of the HCFCs. Since there exists no pure fluid that can replace R22 in the same general way as HFC-134a (R134a) is a replacement for CFC-12, HFC mixtures are suggested as possible substitutes. LÄS MER

  3. 2. Flow Boiling Heat Transfer and Pressure Drop. Experiments and Model Development for Complex Geometries

    Författare :Sven Wellsandt; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pressure drop; zeotropic mixtures; heat transfer; herringbone microfin; dimple plate; modelling; evaporation; flow boiling; experiments;

    Sammanfattning : Two very different evaporator geometries, a dimple plate and a herringbone microfin tube, have been studied. Heat transfer and pressure drop for both pure refrigerants and refrigerant mixtures have been determined experimentally. LÄS MER

  4. 3. Mixture Effects in Shell-and-Tube Condensers. Theory and Calculations

    Författare :Tord Karlsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; shell-and-tube; heat transfer; zeotropic; condensation; mass transfer; mixture;

    Sammanfattning : Zeotropic mixtures have come into more frequent use as working fluids (refrigerants) in heat pumps and air conditioning equipment due to the phase-out of ozone-depleting substances. Substantial drop in performance for shell-side condensation in shell-and-tube condensers when replacing a pure fluid with a mixture has been reported in the literature. LÄS MER

  5. 4. Condensation of Zeotropic Refrigerant Mixtures in Shell-and-Tube Condensers

    Författare :Dave Sajjan; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : .... LÄS MER