Abstract
The ever-increasing demand for renewables in the energy system has drawn attention to technologies capable of minimizing the effect of renewables’ intermittency and shave-off the generation-demand imbalance of the system. Energy storage can help to level peaks in energy demand, thus reducing wastage due to excess capacity during off-peak demand periods. Among the storage media, thermal energy storages (TES) have a large variety of applications, ranging from solar energy utilization and power peaking to industrial waste heat storage. In this study, data collected from an operating commercial stratified tank are used to validate a 2-D axisymmetric CFD model. Temperature profiles at various heights are collected throughout one month with a one-minute refresh rate. The model replicating the tank is generated in COMSOL Multiphysics® and validated by emulating the registered charging phases of the real storage, thus comparing the temperature layers before and after the charging occurs. The model is then employed to optimize the stratification efficiency of the tank, by varying the logics applied to pinpoint optimal values of both inlet water temperature and velocity. The study aims to minimize the MIX number, parameter often utilized in literature to identify the ability of the storage to generate and preserve optimal temperature stratification. Said dimensionless number is evaluated by accounting for the momentum of energy of the different temperature layers found in the water tank. Therefore, a discretization of the thermal storage in five sub-volumes, each of them characterized by the presence of an installed thermocouple, was defined. Finally, the experimental MIX number has been evaluated for the aforementioned temperature profiles.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Abbreviations
- A:
-
Area, m2
- cp:
-
Specific heat, J/kg K
- E:
-
Internal energy, J
- M:
-
Momentum of energy, J m
- MIX:
-
Mix number
- p:
-
Relative pressure, Pa
- P:
-
Absolute pressure, Pa
- Q:
-
Volumetric flow, m3/h
- t:
-
Time, s
- T:
-
Temperature, K
- V:
-
Volume, m3
- y:
-
Vertical displacement, m
- \(\alpha\):
-
Thermal diffusivity, m2/s
- \(\eta_{str}\):
-
Stratification efficiency
- \(\nu\):
-
Kinematic viscosity, m2/s
- ρ:
-
Density, kg/m3
- \(\tau\):
-
Dimensionless time
- avg:
-
Average
- exp:
-
Experimental
- in:
-
Inlet
- mix:
-
Perfectly mixed
- str:
-
Perfectly stratified
- tot:
-
Total simulation time
- CFD:
-
Computational Fluid Dynamics
- HVFPC:
-
High-Vacuum Flat Plate Collectors
- STES:
-
Stratified Thermal Energy Storage
- SSTES:
-
Sensible Stratified Thermal Energy Storage
- TES:
-
Thermal Energy Storage
References
United Nations, Transforming Our World: 2030 Agenda for Sustainable Development, 2015 (Transforming our world: the 2030 Agenda for Sustainable Development | Department of Economic and Social Affairs (un.org)), Access on 17 Mar 2023
A. Frazzica, L. Cerboni, Recent Advancement in Materials and Systems for Thermal Energy Storage. (Switzerland, Springer Nature, 2019)
H.O. Njoku, O.V. Ekechukwu, S.O. Onyegegbu, Analysis of stratified thermal storage systems: an overview. Int. J. Heat Mass Transf. 50, 1017–1030 (2014)
A. Gil, M. Medrano, I. Martorell, A. Làzaro, P. Dolado, B. Zalba, L.F. Cabeza, State of the art on high-temperature thermal energy storage for power generation. Part 1—concepts, materials, and modelization. Renew. Sustain. Energy Rev. 14, 31–55 (2010)
A. Cabelli, Storage tanks-a numerical experiment. Sol. Energy 19, 45–54 (1977)
Z. Lavan, J. Thompson, Experimental study of thermally stratified hot water. Sol. Energy 19, 519–524 (1977)
B.J. Sliwinski, A.R. Mech, T.S. Shih, Stratification in thermal storage during charging, 6th International Heat Transfer Conference (Toronto, Ontario, Canada, 1978)
J. Van Berkel, C.C.M. Rindt, A.A. Van Steemhoven, Modelling of two-layer stratified store. Sol. Energy 67, 65–78 (1999)
R.J. Wood, S.M. Al-Muslahi, P.W. O’Callaghan, S.D. Probert, Thermally stratified hot water storage systems. Appl. Energy 9, 231–242 (1981)
Y.M. Han, R.Z. Wang, Y.J. Dai, Thermal stratification within the water tank. Renew. Sustain. Energy Rev. 13, 1014–1026 (2009)
S. Ievers, W. Lin, Numerical simulation of three-dimensional flow dynamics in a hot water storage tank. Appl. Energy 86, 2604–2614 (2009)
L. Kocijel, V. Mrzljak, V. Glazar, Numerical analysis of geometrical and process parameters influence on temperature stratification in a large volumetric heat storage tank. Energy 194, 1–21 (2020)
J. Lago, F. De Ridder, W. Mazairac, B. De Schutter, A 1-dimensional continuous and smooth model for thermally stratified storage tanks including mixing and buoyancy. Appl. Energy 248, 640–655 (2019)
A. Untrau, S. Sochard, F. Marias, J.M. Reneaume, G.A.C. Le Roux, S. Serra, A fast and accurate 1-dimensional model for dynamic simulation and optimization of a stratified thermal energy storage. Appl. Energy 333, 120614 (2023)
G. Xu, L. Hu, Y. Luo, Z. Tian, J. Deng, G. Yuan, J. Fan, Numerical modeling and parametric analysis of thermal performance for the large-scale seasonal thermal energy storage. Energy Build. 275, 112459 (2022)
J.H. Davidson, D.A. Adams, J.A. Miller, A coefficient to characterize mixing in solar water storage tanks. J. Sol.Energy Eng. 116, 94–99 (1994)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2024 The Author(s), under exclusive license to Springer Nature Switzerland AG
About this paper
Cite this paper
Anacreonte, A.V., Musto, M., Bianco, N., Vitobello, R., Russo, R. (2024). Experimental Analysis and Numerical Optimization of the Stratification Efficiency in a Commercial Stratified Thermal Storage. In: Zhao, J., Kadam, S., Yu, Z., Li, X. (eds) IGEC Transactions, Volume 1: Energy Conversion and Management. IAGE 2023. Springer Proceedings in Energy. Springer, Cham. https://doi.org/10.1007/978-3-031-48902-0_28
Download citation
DOI: https://doi.org/10.1007/978-3-031-48902-0_28
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-031-48901-3
Online ISBN: 978-3-031-48902-0
eBook Packages: EnergyEnergy (R0)