Numerical Analysis of Latent Thermal EnergyStorage in Coaxial Component

Sammanfattning: Latent Thermal Energy Storage, LTES, is a system for storing energy for later use. It isused in applications such as buildings, electronics and space shuttles. The problem associatedwith the system is the relatively low charging and discharging power i.e. the timeto complete melting and solidification - in large because of the low thermal conductivityof the phase change material, PCM. Several methods to improve the performance of thesystem with existing PCMs have been examined, for example use of fins and multipletubes within the heat exchanger.This thesis examines latent thermal energy storage in a coaxial component, duringboth melting and solidification using PCM RT35. The examination is a comparativestudy of a simplified, two-dimensional model of a horizontally orientated shell and tubeheat exchanger - versus - a vertically orientated one. The analysis is made in CFDprogramme Ansys Fluent 17.1, through four different models.The results show that the vertical orientation performs better in both cases, meltingand solidification. The energy transfer amount within the phase change time is the same,although the vertical orientation is approximately 200% faster to complete melt and 90%to complete solidification. The main reason for this discrepancy is the impact of gravity,which is more prominent in the vertical orientation.