A Flow Rate Dependent 1D Model for Thermally Stratified Hot-Water Energy Storage

Joseph Rendall, Fernando Karg Bulnes, Kyle Gluesenkamp, Ahmad Abu-Heiba, William Worek and Kashif Nawaz
Additional contact information
Joseph Rendall: Multifunctional Equipment Research Group, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
Fernando Karg Bulnes: Southwest Research Institute, San Antonio, TX 78238, USA
Kyle Gluesenkamp: Multifunctional Equipment Research Group, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
Ahmad Abu-Heiba: Multifunctional Equipment Research Group, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
William Worek: Department of Mechanical and Industrial Engineering, Texas A&M University Kingsville, Kingsville, TX 78363, USA
Kashif Nawaz: Multifunctional Equipment Research Group, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA

Energies, 2021, vol. 14, issue 9, 1-17

Abstract: Stratified tank models are used to simulate thermal storage in applications such as residential or commercial hot-water storage tanks, chilled-water storage tanks, and solar thermal systems. The energy efficiency of these applications relates to the system components and the level of stratification maintained during various flow events in the tank. One-dimensional (1D) models are used in building energy simulations because of the short computation time but often do not include flow-rate dependent mixing. The accuracy of 1D models for plug flow, plug flow with axial conduction, and two convection eddy-diffusivity models were compared with experimental data sets for discharging a 50-gal residential tank and recharging the tank with hot water from an external hot-water source. A minimum and maximum relationship for the eddy diffusivity factor were found at Re <2100 and >10,000 for recirculation of hot water to the top of the tank and vertical tubes inletting cold water at the bottom. The root mean square error decreased from >4 °C to near 2 °C when considering flow-based mixing models during heating, while the exponential decay of the eddy diffusion results in a root mean square error reduction of 1 °C for cone-shaped diffusers that begin to relaminarize flow at the inlet.

Keywords: stratification; thermal-energy storage; 1D flow model; hot-water tanks (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
https://www.mdpi.com/1996-1073/14/9/2611/pdf (application/pdf)
https://www.mdpi.com/1996-1073/14/9/2611/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:14:y:2021:i:9:p:2611-:d:548109

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().