• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Engineering
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Engineering
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    Numerical heat transfer model of a traditional ice cellar with passive cooling methods

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Wendler_K_2011.pdf
    Size:
    14.61Mb
    Format:
    PDF
    Download
    Author
    Wendler, Kyle D.
    Keyword
    Food preservation
    Thermosyphons
    Soil temperature
    Permafrost
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/12697
    Abstract
    Permafrost ice cellars have been used for generations by Arctic communities for subsistence food storage. Many of these ice cellars have been recently reported to be difficult or impossible to maintain due to thawing and water accumulation inside the cellar. The thesis objective is to investigate the effectiveness of implementing passive techniques to lower the surrounding permafrost temperature, ideally to 0°F, the USDA recommended temperature, throughout the year. Numerical finite element modeling was used to investigate the effects on permafrost temperature with the addition of two-phase, closed thermosyphons and/or ground insulation. Thermosyphon condensers installed both above and below ground were studied. The numerical models were created using Comsol Multiphysics. The modeling results indicated that the addition of thermosyphons and insulation caused a decrease in permafrost temperatures surrounding the ice cellar, although the target temperature of 0°F could not be maintained throughout the year by any of the methods studied. Subsurface insulation decreased the amplitude between the minimum and maximum temperature of the cellar wall 4.5°C. Air thermosyphons decreased the average temperature 8.5°C, and with additional insulation, 90C. Ground thermosyphons were less effective, decreasing the average wall temperature 2.4°C. Additionally, thermosyphon performance was found to be rate-limited by conduction through permafrost.
    Description
    Thesis (M.S.) University of Alaska Fairbanks, 2011
    Table of Contents
    1. Introduction -- 1.1. Ice cellars -- 1.2. Cooling of permafrost -- 1.3. Objective and scope of thesis -- 2. Literature review -- 2.1. Ice cellars -- 2.2. Permafrost -- 2.2.1. Basics of permafrost -- 2.2.2. Northern Alaska permafrost conditions -- 2.2.3. Methods of cooling permafrost -- 2.2.4. Phase change material -- 2.3. Thermosyphons -- 2.3.1. Basics of thermosyphons -- 2.3.2. History of thermosyphons -- 2.3.3. Lab and test sites -- 2.3.4. Finite element modeling -- 2.4. Sub-surface insulation -- 2.4.1. Basics of insulation for permafrost preservation -- 2.4.2. Lab and test sites -- 2.4.3. Analytical and modeling solutions -- 3. Method of modeling and verification -- 3.1. Introduction -- 3.2. Methods -- 3.2.1. Volume fraction of water and ice -- 3.2.2. Latent heat effects -- 3.2.3. Sensible heat -- 3.2.4. Thermal conductivity -- 3.2.5. Density -- 3.2.6. Surface temperature (n-Factors) -- 3.2.7. Air-ground thermosyphons -- 3.2.8. Ground-ground thermosyphons -- 3.2.9. Model symmetry -- 3.3. Model verification -- 3.3.1. Stefan solution -- 3.3.2. Two dimensional base-case ice cellar verification -- 3.3.3. Three dimensional base ice cellar verification -- 4. Results and discussion -- 4.1. Introduction -- 4.2. Model parameters -- 4.2.1. Basic material properties -- 4.2.2. Constant model parameters -- 4.2.3. Barter Island climate averages -- 4.2.4. 2-D basic model geometric size -- 4.2.5. 3-D geometric size -- 4.2.6. Initial and boundary conditions -- 4.2.7. Mesh -- 4.3. Porosity study -- 4.3.1. Introduction -- 4.3.2. Effects -- 4.3.3. Conclusions -- 4.4. Subsurface insulation -- 4.4.1. Introduction -- 4.4.2. Effects -- 4.4.3. Conclusions -- 4.5. Heat transfer coefficient of air thermosyphons -- 4.5.1. Introduction -- 4.5.2. Effects -- 4.5.3. Conclusions -- 4.6. Air thermosyphon -- 4.6.1. Introduction -- 4.6.2. Effects -- 4.6.3. Conclusions -- 4.7. Air thermosyphons with sub-surface insulation -- 4.7.1. Introduction -- 4.7.2. Effects -- 4.7.3. Conclusions -- 4.8. Ground thermosyphon -- 4.8.1. Introduction -- 4.8.2. Effects -- 4.8.3. Conclusions -- 4.9. Comparison of different configurations -- 4.9.1. Air thermosyphons with and without insulation -- 4.9.2. Air and ground thermosyphons -- 4.9.3. Table of different configurations -- 5. Conclusions and future work -- 5.1. Conclusions -- 5.2. Future work --5.2.1. Natural convection -- 5.2.2. Governing equations for thermosyphons -- 5.2.3. Optimum radius for evaporator -- 5.2.4. Ground thermosyphons with insulation -- 5.2.5. Other considerations -- References.
    Date
    2011-12
    Type
    Thesis
    Collections
    Engineering

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska Fairbanks is an affirmative action/equal opportunity employer and educational institution and is a part of the University of Alaska system.

    ©UAF 2013 - 2023 | Questions? ua-scholarworks@alaska.edu | Last modified: September 25, 2019

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.