Numerical simulation of a PCM packed bed system: A review

The detailed study of latent packed bed thermal energy storage (TES) system has been a great topic of interest in the literature. Experimental measurements have been conducted to analyze the performance of these systems, however, the complex transient nature of latent TES makes necessary the use of numerical models for detailed study and evaluation of key design parameters, which lead to a numerous scientific contributions in the field. Different and diverse numerical models have been developed, which can be mainly divided into single phase models, Schumman's model, concentric dispersion model, and continuous solid phase model. This paper provides an extensive comprehensive revision of the different numerical models, highlighting the key aspects of each one as well as the main findings in the field. Furthermore, the performance of the different methodologies are discussed and compared. The most important empirical correlations used in the different models in order to take into account physics, such as natural convection inside the spheres or effective thermal conductivity of heat transfer fluid, are also given.The work partially funded by the Spanish Government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement no. PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union's Horizon 2020 research and innovation programme under Grant agreement no. 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940