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 ISBN 978-84-697-0467-7 (Unpublished)
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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/ | |||||||||||||||
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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: |
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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 |
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