Sökning: "R22"

Hittade 4 avhandlingar innehållade ordet R22.

1. 1. Phase-out of refrigerant R22

   Författare :Anders Johansson; KTH; []
   Nyckelord :Retrofit; Phase-out; CFC; HCFC; HFC; R22; R407C; R417A; R404A; R134a; Ozone depletion; Zeotropic refrigerant mixture; Circulated composition; Measurement; Energy; Energy efficiency; System; Systems analysis; Modelling; Simulation; Prediction;

   Sammanfattning : .... LÄS MER

3. 2. 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

4. 3. 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

5. 4. Nonazeotropic mixtures as working fluids in large heat pumps - Heat transfer in a falling film evaporator and system simulations

   Författare :Karin Munch; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The thesis is divided into two main parts, the first onedealing with heat transfer in the evaporator and the secondone dealing with simulations of the whole heat pump cyclewith nonazeotropic mixtures. One of the aims with the heat transfer studies was to investigate if the additional mass transfer resistance, introduced when mixtures are used, can be reduced in a thin falling film with high turbulence compared with corresponding one for a horizontal tube. LÄS MER