Proposed Modifications for Models of Heat Transfer Problems Involving Partially Melted Phase Change Processes

    Volume 6, Issue 9 (October 2009)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 3 August 2009

    Page Count: 20


    Fang, Yuan
    Graduate Research Assistant, Dept. of Civil, Environmental, and Architectural Engineering, The Univ. of Kansas, Lawrence, KS

    Medina, Mario A.
    P.E., Associate Professor, Dept. of Civil, Environmental, and Architectural Engineering, The Univ. of Kansas, Lawrence, KS

    (Received 4 August 2008; accepted 30 June 2009)

    Abstract

    Air conditioning electricity consumption in summer represents a challenge in many areas with hot and humid climates. When incorporated into lightweight residential building walls, phase change materials (PCMs) can increase the effective thermal mass of the wall, which in turn will shift part of the cooling load to off-peak times and lower the peak space cooling load of the building. From analyses of experimental data, it was found that it was very likely that the PCMs, once integrated into the walls, would “start” the phase change process from partially melted states. Currently used simulation models, including the most widely accepted models, such as the effective heat capacity method and the enthalpy method, come short when handling phase change processes that start from partially melted states. The characteristics of how the heat is absorbed or released during the phase change process were studied through experimental and theoretical analyses. A differential scanning calorimeter (DSC) method and its detailed steps, used to obtain latent heat of fusion distribution along the phase change temperature range, are presented. Based on the DSC test data, a modified PCM model for a paraffin-based PCM was developed.


    Paper ID: JAI102059

    DOI: 10.1520/JAI102059

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    Author
    Title Proposed Modifications for Models of Heat Transfer Problems Involving Partially Melted Phase Change Processes
    Symposium Second Symposium on Heat-Air-Moisture Transport: Measurements and Implications in Buildings, 2009-04-20
    Committee C16