Analytical Modeling of a Bubble Column Dehumidifier

Bubble column dehumidifiers are a compact, inexpensive alternative to conventional fin-tube dehumidifiers for humidification-dehumidification (HDH) desalination, a technology that has promising applications in small-scale desalination and industrial water remediation. In this paper, algebraic equati...

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Bibliographic Details
Main Authors: Tow, Emily W., Lienhard, John H.
Other Authors: Massachusetts Institute of Technology. Department of Mechanical Engineering
Format: Article
Language:en_US
Published: ASME International 2014
Online Access:http://hdl.handle.net/1721.1/86322
https://orcid.org/0000-0002-2901-0638
https://orcid.org/0000-0002-0606-713X
Description
Summary:Bubble column dehumidifiers are a compact, inexpensive alternative to conventional fin-tube dehumidifiers for humidification-dehumidification (HDH) desalination, a technology that has promising applications in small-scale desalination and industrial water remediation. In this paper, algebraic equations for relevant mean heat and mass transfer driving forces are developed for improved modeling of bubble column dehumidifiers. Because mixing in the column ensures a uniform liquid temperature, the bubble column can be modeled as two single stream heat exchangers in contact with the column liquid: the seawater side, for which a log-mean temperature difference is appropriate, and the gas side, which has a varying heat capacity and mass exchange. Under typical conditions, a log-mean mass fraction difference is shown to drive latent heat transfer, and an expression for the mean temperature difference of the moist gas stream is presented. These expressions will facilitate modeling of bubble column heat and mass exchangers.