Performance And Heat Transfer Enhancement Of A Latent Heat Thermal Energy Storage System

Energy storage technology cannot only solve the problem of environmental pollution and energy waste caused by economic development,but also can solve the contradiction between energy supply and demand.Latent heat storage is based on the use of phase change material,which can absorb or release large amounts of heat during their phase transition.So,latent heat thermal exchanger is one of the important ways to improve energy efficiency.In current work,air is used as the heat transfer fluid,the dynamic heat transfer performance of a latent heat thermal exchanger with bundled tube structure is studied,and software Fluent 15.0 was employed in the numerical simulation.Based on the two-dimensional numerical model established in the paper,transient simulations of the charging processes are performed;different inlet air mass flow rate on the heat transfer performance is considered,and the melting processes of the storage units with staggered tube bundle structure and parallel tube bundle structure are compared with that of flat plate structure.The results show that during the melting process,the heat transfer rate of the latent heat thermal exchanger can be increased by increasing the heat transfer surface between the PCM container and air,the air turbulence in the channel,and the gas inlet mass flow rate.The thermal exchange unit with staggered tube bundle structure is a good choice for its larger heat transfer surface and higher degree of air turbulence.Secondly,the enhancement of additional fins on the heat transfer of the staggered tube bundle structure thermal exchanger is studied,temperature figures and streamlines diagrams is present.The results show that fins which are attached to the inner wall of the container tube can effectively improve the heat transfer performance of the latent heat thermal exchanger.Finally,based on the three-dimensional simulation,the enhancement effect of the air-side vortex generators on the heat transfer performance is studied,Taking the pressure drop caused by the addition of the vortex generator into account.The results show that vortex generators can improve the heat transfer performance of the heat exchanger significantly,and the appropriate vortex generator arrangement can effectively reduce the pressure loss caused by the vortex generators.This paper summarizes the technical characteristics of latent heat thermal exchanger,and points out the future research direction of this technology.