CFD analysis of melting process in a shell-and-tube latent heat storage for concentrated solar power plants. (15th February 2016)

• Record Type: Journal Article
• Authors: Fornarelli, F.; Camporeale, S.M.; Fortunato, B.; Torresi, M.; Oresta, P.; Magliocchetti, L.; Miliozzi, A.; Santo, G.
• Is Part Of: Applied energy. Volume 164(2016)
• Page Start: 711
• Page End: 722
• Publication Date: 2016-02-15
• Subjects: CFD -- Thermal Energy Storage (TES) -- Phase Change Material (PCM) -- Molten salts -- Shell and tube -- Enthalpy-porosity model; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2015.11.106
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Numerical simulation of the melting process in vertical latent heat storage device. Shell and tube heat storage device for CSP (concentrated solar power) applications. Conjugate heat transfer model including HTF, steel tube, and PCM. Comparison of the results obtained from convective and pure conductive models. Influence of the mushy zone constant, A mush, on enthalpy-porosity model. Abstract: A latent heat storage system for concentrated solar plants (CSP) is numerically examined by means of CFD simulations. This study aims at identifying the convective flows produced within the melted phase by temperature gradients and gravity. Simulations were carried out on experimental devices for applications to high temperature concentrated solar power plants. A shell-and-tube geometry composed by a vertical cylindrical tank, filled by a Phase Change Material (PCM) and an inner steel tube, in which the heat transfer fluid (HTF) flows, from the top to the bottom, is considered. The conjugate heat transfer process is examined by solving the unsteady Navier–Stokes equations for HTF and PCM and conduction for the tube. In order to take into account the buoyancy effects in the PCM tank the Boussinesq approximation is adopted. The results show that the enhanced heat flux, due to natural convective flow, reduce of about 30% the time needed to charge the heat storage. A detailed description of the convective motion in the melted phase and the heat flux distribution between the HTF and PCM are reported. The effect of the mushy zone constant is also investigated.