Analysis of entropy generation mechanisms in a desiccant wheel

This work presents a novel detailed analysis of entropy generation mechanisms in a desiccant wheel (DW) by the the direct method, enabling differentiation of entropy sources by type and location. A detailed model of the desiccant-based system, implemented in Modelica, is used to compute entropy generation from various phenomena. Furthermore, a novel idealized dehumidification process is proposed and compared to simulation results. Results show that irreversible heat transfer dominates entropy generation (ca. 40 % in the reference case), followed by mass transfer, dissipation, and mixing. Through parametric variation of regeneration temperature and wheel rotational speed, optimal operating points that minimize entropy generation are identified. It is demonstrated that entropy generation can be minimized by reaching an operating point with minimal temperature spread at the wheel outlet surface. Comparison with the ideal process reveals that a significant portion of the system’s exergy requirements stems from rreversibilities within the DW itself, rather than from losses in discharged air streams.

Subjects

Entropy

desiccant wheel

modelica

second law

ideal dehumidification

DDC Class

628: Sanitary; Municipal

621: Applied Physics

518: Numerical Analysis

Funding(s)

Energieeffiziente Bereitstellung von klimatischen Bedingungen innerhalb von Trockenräumen zur Batterieproduktion

Funding Organisations

Hamburgische Investitions- und Förderbank

Lizenz

https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication version

submittedVersion

Name

Analysis_of_Entropy_Generation_Mechanisms_in_a_Desiccant_Wheel.pdf

Type

Main Article

Size

1.87 MB

Format

Adobe PDF

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Analysis of entropy generation mechanisms in a desiccant wheel