Search for dissertations about: "Conductivity measurement"

Showing result 1 - 5 of 71 swedish dissertations containing the words Conductivity measurement.

  2. 1. Determination of the thermal conductivity of the insulation in district heating mains : Field measurements

    Author : Karin Margaretha Borgström; Högskolan i Halmstad; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; district heating main; field measurements; thermal conductivity; measuring method; heat flow measurement; heat flux sensor; Material physics with surface physics; Materialfysik med ytfysik;

    Abstract : This thesis concerns the development of a measurement method for determination in the field of the thermal conductivity of the insulation in buried district heating mains. The thermal conductivity of the insulation is calculated from the measured value of the radial heat flow through the heating main, the measured temperature difference across the insulation, and the dimensions of the heating main. READ MORE

  4. 2. Calculation and Measurement Methods for the Performance of Solar Collectors. Models of Flat Plate Collectors, Transparent Insulation and Efficiency Factors

    Author : Bengt Hellström; Avdelningen för Energi och byggnadsdesign; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transparent insulation; Test method; Calculation method; Concentrating collector; Efficiency factor; Fin efficiency; Flat plate collector; Heat conductivity; Honeycomb; Measurement method; Performance; Solar transmittance; Solar collector; Collector model; Energy research; Energiforskning;

    Abstract : This thesis deals with models of flat plate collectors, transparent insulation and efficiency factors. An equation for the energy output from a glazed flat plate collector is derived by modelling the collector efficiency factor, F´ as the sum of a constant and a temperature dependent part. READ MORE

  5. 3. Thermal Conductivity of Hygroscopic Foams Based on Cellulose Nanomaterials

    Author : Varvara Apostolopoulou-Kalkavoura; Lennart Bergström; Tatiana Budtova; Stockholms universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; thermal conductivity; cellulose nanomaterials; foams; hygroscopic; super-insulating; phonon scattering; moisture uptake; heat transport; Materials Chemistry; materialkemi;

    Abstract : Biobased super-insulating materials could mitigate climate change by minimizing the use of petroleum-based materials, creating artificial carbon sinks and minimizing the energy needed to maintain pleasant interior conditions. Cellulose nanomaterials (CNM) produced from abundantly available cellulose sources constitute versatile, highly anisotropic raw materials with tunable surface chemistry and high strength. READ MORE

  6. 4. Characterization of Conduction and Polarization Properties of HVDC Cable XLPE Insulation Materials

    Author : Hossein Ghorbani; Hans Edin; Gilbert Teyssedre; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HVDC insulation; power cable insulation; cross-linked polyethylene insulation; conductivity; dielectric losses; space charge; Electrical Engineering; Elektro- och systemteknik;

    Abstract : High voltage direct current (HVDC) cables with extruded insulation system were introduced in 1998. Since then this technology has been growing rapidly with many installations that are today operational at voltages up to 320 kV. READ MORE

  7. 5. Characterization of Conduction and Polarization Properties of HVDC Cable XLPE Insulation Materials

    Author : Hossein Ghorbani; Hans Edin; Erling Ildstad; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HVDC insulation; power cable insulation; cross-linked polyethylene insulation; conductivity; dielectric losses; space charge; HVDC isolation; kraftkabel isolation; tvärbunden polyeten isolationsmaterial; elektrisk ledningsförmåga; dielektriska förluster; rymdladdning; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Since its first introduction in 1998, extruded direct current (DC) cable technology has been growing rapidly leading to many cable system installations with operation voltages up to 320 kV. Cable manufacturers invest heavily on technology development in this field and today extruded DC cable systems for operation voltages as high as 525 kV are commercially available. READ MORE