E3S Web of Conferences (Jan 2017)

Modeling the defrost process in complex geometries – Part 1: Development of a one-dimensional defrost model

  • van Buren Simon,
  • Hertle Ellen,
  • Figueiredo Patric,
  • Kneer Reinhold,
  • Rohlfs Wilko

DOI
https://doi.org/10.1051/e3sconf/20172200023
Journal volume & issue
Vol. 22
p. 00023

Abstract

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Frost formation is a common, often undesired phenomenon in heat exchanges such as air coolers. Thus, air coolers have to be defrosted periodically, causing significant energy consumption. For the design and optimization, prediction of defrosting by a CFD tool is desired. This paper presents a one-dimensional transient model approach suitable to be used as a zero-dimensional wall-function in CFD for modeling the defrost process at the fin and tube interfaces. In accordance to previous work a multi stage defrost model is introduced (e.g. [1, 2]). In the first instance the multi stage model is implemented and validated using MATLAB. The defrost process of a one-dimensional frost segment is investigated. Fixed boundary conditions are provided at the frost interfaces. The simulation results verify the plausibility of the designed model. The evaluation of the simulated defrost process shows the expected convergent behavior of the three-stage sequence.