Sökning: "heat pump"

Visar resultat 36 - 40 av 110 avhandlingar innehållade orden heat pump.

  1. 36. Frosting and Defrosting of Air-Coils

    Författare :Per Fahlén; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; heat pump; defrost; air-coil; air-source; control; frost; optimized;

    Sammanfattning : Experience indicates that air-source heat pumps have more operating problems than ground-source heat pumps. One major factor pertains to the effects of frosting and the subsequent need for defrosting. This thesis reviews previous research and practical experience and presents novel experimental facilities to investigate the process of frosting. LÄS MER

  3. 37. A Sociological Approach to Indoor Environment in Dwellings : Risk factors for Sick Building Syndrome (SBS) and Discomfort

    Författare :Karin Engvall; Dan Norbäck; Eva Sandstedt; Göran Strid; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Medicine; Indoor environment; Questionnaire; Atopy; Building age; Indoor air quality; Sick building syndrome SBS ; Validation; Dwelling; Energy conservation; Mechanical ventilation; Building dampness; Building reconstruction; Wood heating; Electric heating; Heat pump; Thermal Insulation; Sealing; Medicin; Dermatology and venerology; clinical genetics; internal medicine; Dermatologi och venerologi; klinisk genetik; invärtesmedicin; arbets- och miljömedicin; Occupational and Environmental Medicine;

    Sammanfattning : The principal aim was to study selected aspects of indoor environment in dwellings and their association with symptoms compatible with the sick building syndrome (SBS). A validated questionnaire was developed specifically for residential indoor investigations, using sociological principles and test procedures. LÄS MER

  4. 38. Distributed thermal response tests : New insights on U-pipe and Coaxial heat exchangers in groundwater-filled boreholes

    Författare :José Acuña; Björn Palm; Jeffrey Spitler; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Borehole heat exchangers; Distributed Thermal Response Test; Ground Source Heat Pumps; Coaxial; U-pipe; Multi-pipe; Pipe-in-pipe; Multi-chamber; Groundwater; Thermosyphon; SRA - Energy; SRA - Energi;

    Sammanfattning : U-pipe Borehole Heat Exchangers (BHE) are widely used today in ground source heating and cooling systems in spite of their less than optimal performance. This thesis provides a better understanding on the function of U-pipe BHEs and Investigates alternative methods to reduce the temperature difference between the circulating fluid and the borehole wall, including one thermosyphon and three different types of coaxial BHEs. LÄS MER

  5. 39. Some PDAE aspects of the numerical simulation of a CO2 heat pump

    Författare :Magnus Strömgren; Michael Hanke; Claus Führer; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical analysis; Numerisk analys;

    Sammanfattning : We consider network modelling and numerical simulation of a simple CO2 heat pump consisting of a compressor, a valve and two heat exchangers. In a first step we investigate analytical and numerical properties of the heat exchanger model. LÄS MER

  7. 40. 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