elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

Numerical analysis of natural convection in a latent heat thermal energy storage system containing rectangular enclosures

Vogel, Julian and Johnson, Maike and Eck, Markus and Laing, Dörte (2014) Numerical analysis of natural convection in a latent heat thermal energy storage system containing rectangular enclosures. In: Conference proceedings Eurotherm Seminar #99. Eurotherm Seminar #99 - Advances in Thermal Energy Storage, 28.-30. Mai 2014, Lleida, Spanien. ISBN 978-84-697-0467-7 (Unpublished)

[img] PDF
516kB

Abstract

Natural convection in the liquid phase of a phase change material (PCM) is often neglected in the analysis and design of latent heat thermal energy storage (LHTES) systems. However, depending on geometry and material properties, the influence of natural convection can be significant. This is also the case in an experimental LHTES lab-scale storage unit for high temperature PCMs that was designed, built and operated at DLR. The unit is a storage adaptation of a flat plate heat exchanger. The space between the heated flat plates forms rectangular enclosures, which are filled with PCM. The behavior of such a system is to be described by numerical methods. First, a method that accounts only for heat conduction was used. In some cases, simulated results diverged considerably from experimental data. This divergence was expected to be mostly caused by natural convection. In this work, improved simulation methods are applied that include the modeling of natural convection. For a detailed reference solution, a sophisticated CFD-Method that solves the Navier-Stokes-Equations is used. The results are validated with data from the above mentioned DLR storage test unit filled with the eutectic mixture of potassium nitrate (KNO3) and sodium nitrate (NaNO3). Although differences between simulation results and experimental data still remain, the agreement has improved greatly in comparison to previous heat conduction simulations. Possible causes for divergences and suggestions for further improvement are given. Moreover, the detailed flow and temperature fields driven by natural convection are presented and discussed. Finally, the influence of natural convection on the thermal power characteristic is analyzed. A strong influence is observed for the charging process, where the power input is considerably enhanced. The discharging process is only slightly affected.

Item URL in elib:https://elib.dlr.de/113475/
Document Type:Conference or Workshop Item (Speech)
Title:Numerical analysis of natural convection in a latent heat thermal energy storage system containing rectangular enclosures
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Vogel, Julianjulian.vogel (at) dlr.dehttps://orcid.org/0000-0001-9792-2332
Johnson, Maikemaike.johnson (at) dlr.deUNSPECIFIED
Eck, MarkusUNSPECIFIEDUNSPECIFIED
Laing, DörteUNSPECIFIEDUNSPECIFIED
Date:2014
Journal or Publication Title:Conference proceedings Eurotherm Seminar #99
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
ISBN:978-84-697-0467-7
Status:Unpublished
Keywords:Latent heat thermal energy storage; phase change material (PCM); solidification and melting; natural convection; rectangular enclosures; numerical simulation (CFD)
Event Title:Eurotherm Seminar #99 - Advances in Thermal Energy Storage
Event Location:Lleida, Spanien
Event Type:international Conference
Event Dates:28.-30. Mai 2014
Organizer:Universitat de Lleida
HGF - Research field:Energy
HGF - Program:Storage and Cross-linked Infrastructures
HGF - Program Themes:Thermal Energy Storage
DLR - Research area:Energy
DLR - Program:E SP - Energy Storage
DLR - Research theme (Project):E - Thermochemical Processes (Storage)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Thermal Process Technology
Deposited By: Vogel, Julian
Deposited On:27 Jul 2017 10:48
Last Modified:31 Jul 2019 20:11

Repository Staff Only: item control page

Browse
Search
Help & Contact
Information
electronic library is running on EPrints 3.3.12
Copyright © 2008-2017 German Aerospace Center (DLR). All rights reserved.