Experimental and Numerical Investigation of Combined Sensible/Latent Thermal Energy Storage for High-Temperature Applications

Lukas Geissbühler; Simone Zavattoni; Maurizio Barbato; Giw Zanganeh; Andreas Haselbacher; Aldo Steinfeld

doi:10.2533/chimia.2015.799

Experimental and Numerical Investigation of Combined Sensible/Latent Thermal Energy Storage for High-Temperature Applications

Authors

Lukas Geissbühler Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland
Simone Zavattoni Department of Innovative Technologies, SUPSI, CH-6928 Manno, Switzerland
Maurizio Barbato Department of Innovative Technologies, SUPSI, CH-6928 Manno, Switzerland
Giw Zanganeh Airlight Energy Manufacturing SA, Via Industria 10, CH-6710 Biasca, Switzerland
Andreas Haselbacher Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland. haselbac@ethz.ch
Aldo Steinfeld Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland

DOI:

https://doi.org/10.2533/chimia.2015.799

Keywords:

Packed bed, Phase change material, Simulation, Thermal energy storage, Thermocline

Abstract

Combined sensible/latent heat storage allows the heat-transfer fluid outflow temperature during discharging to be stabilized. A lab-scale combined storage consisting of a packed bed of rocks and steel-encapsulated AlSi12 was investigated experimentally and numerically. Due to the small tank-to-particle diameter ratio of the lab-scale storage, void-fraction variations were not negligible, leading to channeling effects that cannot be resolved in 1D heat-transfer models. The void-fraction variations and channeling effects can be resolved in 2D models of the flow and heat transfer in the storage. The resulting so-called bypass fraction extracted from the 2D model was used in the 1D model and led to good agreement with experimental measurements.