CFD modeling and experimental validation of a high-temperature pilot-scale combined sensible/latent thermal energy storage

Zavattoni, Simone and Barbato, Maurizio and Geissbühler, Lukas and Haselbacher, Andreas and Zanganeh, Giw and Steinfeld, Aldo (2015) CFD modeling and experimental validation of a high-temperature pilot-scale combined sensible/latent thermal energy storage. In: SCCER Heat and Electricity Storage – 2° Symposium, 5-6 May 2015, PSI - Villigen.

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Abstract

The development of reliable and cost-effective TES systems is among the main technical challenges to realize the long-term energy policy (Energy Strategy 2050) developed by the Federal Council. In the field of high-temperature TES, packed beds with low-cost filler material can be considered as representative solution for sensible heat storage and even the most suitable for air-based systems such as advanced adiabatic compressed air energy storage (AA-CAES). However, an intrinsic drawback of this solution is the decrease of the heat transfer fluid (HTF) outlet temperature, towards the end of the discharge phase. This drawback can be avoided if a latent TES, based on phase change material (PCM), is exploited instead. However, the high cost of the PCM is among the limiting factors on its integration into an AA-CAES plant. For this reason, the idea of adding a small amount of PCM on top of the packed bed was proposed with the aim of mitigating the HTF temperature decrease during discharging limiting, at the same time, the increment of the overall TES system cost. The present study aims at modeling, by means of computational fluid dynamics (CFD) simulations, the thermo-fluid dynamics behavior of a thermocline combined sensible/latent heat storage. A simplified 2D axisymmetric numerical model was developed and time-dependent CFD simulations were performed. The channeling effect was accounted for by modeling an exponential decay of the void fraction in the radial direction of the packed bed. The results of the CFD simulation were satisfactorily validated with experimental data gathered from a pilot-scale thermal energy storage (TES). The CFD simulations were performed with Fluent 15.0 code from ANSYS.

Item Type:	Article in conference proceedings or Presentation at a conference (Poster)
Subjects:	Engineering
Department/unit:	Dipartimento tecnologie innovative > Istituto di ingegneria meccanica e tecnologia dei materiali
Depositing User:	Simone Zavattoni
Date Deposited:	12 May 2015 11:36
Last Modified:	12 May 2015 11:36
URI:	http://repository.supsi.ch/id/eprint/6503

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