Performance evaluation of a curved slab-shaped macro-encapsulated phase change material through experimental analysis and CFD simulations for residential latent heat storage applications

Details

Supervisors

Jeanmart, Hervé

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil électromécanicien, à finalité spécialisée: énergie

Abstract

One of the strategies for achieving climate targets is the development of renewable energies. However, the intermittent nature of these sources implies a coupling with storage systems to ensure a balanced supply/demand. Among the existing technologies, latent heat thermal energy storage (LHTES) with macro-encapsulated phase change materials (PCM) is considered here. The objective of this work is to evaluate the thermal performance of a curved slab-shaped capsule in the context of residential heating applications. Firstly, the flow conditions experienced by a capsule stacked in a thermal storage tank for the instantaneous heating of a shower were determined. The capsule was then positioned at the centre of a cylindrical experimental device, where the pre-established flow conditions were applied. The response was quantified by means of temperature sensors. Finally, the configuration was replicated in a simplified manner in computational fluid dynamics (CFD) simulations. By assuming a constant boundary temperature, the convection around the capsule was modelled in stationary mode, and the phase change was analysed in transient mode. Experimental tests demonstrated that the phase change duration of this capsule is five times shorter than that of an equivalent volume conventional geometry. Simulations allowed to establish an empirical law for heat transfer around this specific shape. Finally, a model is proposed for determining the effective heat transfer coefficient of a storage tank based on the equivalent packed bed's porosity and the capsule's geometry.