Thermo-convective Study of a Shell and Tube Thermal Energy Storage Unit

Abstract

In this paper, we have studied numerically thermo-convective characteristics between a heat transfer fluid (HTF) IntroductionThe problems of energies consumption have aggravated due to the increase of industrial, commercial and residential activities; parallelly, the current technological development suffers from the depletion of fossil energy. In such case, there is a huge need to use renewable energy sources because they represent a good solution to such problems, and among the known renewable energies, the thermal solar remains the most exploited type. As it is unstable along the time (day and night) and due to its periodic nature, we must use a thermal energy storage device in order to ensure the continuity of this energy during the time. Amongst the types of thermal storage systems, there is the thermal latent heat storage based on the use of phase change materials (PCMs) which have advantages such as high storage density. Many numerical and experimental studies were performed on the latent thermal energy storage systems.From the previous studies of Yang et al. [1] and Trp et al.[2], the thermal storage depends mainly on the HTF inlet velocity (or mass flow rate), HTF inlet temperature, and geometric parameters. Therefore, the choice of the operating conditions and geometric parameters depends on the required heat transfer rate and the time storage in which the energy will be stored or delivered according to Trp et al. [2]. In order to explore the effect of the adequate choice of the PCM, El Qarnia [3] has studied numerically the thermal performance of a solar latent heat storage unit (LHSU) during charging and discharging cycle by using three kinds of PCMs (n-octadecane, Paraffin wax and Stearic acid) as storage mediums. The results showed that a water production at high temperature depends on the careful selection of PCMs. Recently, Tao and Carey [4] have investigated experimentally the effect of PCM thermo-physical characteristics on the performance of shell and tube LHSU in order to improve its performance. The results have showed that the PCM thermo-physical characteristics are the responsible parameters to improve the time and heat transfer of the system. A phase change process dominated by heat conduction in a shell and tube TES unit has been studied experimentally and numerically by solving a developed analytical model by Kibria et al. [5]

Numerical investigation of the shell configuration effect on the melting of various phase change materials in the presence of porous medium and non‐Newtonian fluid

“…To validate the solution method, the results of the numerical simulation are compared with the numerical results of Elmirah et al 20 and Kumar and Krishna 33 . According to Figures 5 and 6, the highest errors in the graphs of liquid fraction and the outlet temperature are equal to 5.5% and 0.8%, respectively.…”

“…Also, tube radius is a more important parameter than thickness for better heat transfer. Elmirah et al 20 studied the heat transfer of the shell–tube thermal energy storage system considering the limited Reynolds number from 100 to 1500. They displayed that the length, diameter of the shell, and Reynolds number have a noticeable influence on the temperature of the outlet fluid, and the Reynolds number is also a highly impressive parameter that has a meaningful influence on the time and rate of freezing and melting of materials.…”

Review on latent thermal energy storage using phase change material

“…In the opposite process, there is no difference between positions. The thermo-convective features between a water (HTF) and paraffin wax (PCM) result in conduction and forced convection in ESS was studied by Abderrahmane et al [23]. Enthalpy evaluation was employed to investigate the thermal characteristics during phase change processes.…”

Numerical Predication of Solidification Phenomena of Phase Change Material in Concentric Annulus Pipe

“…Enthalpy -porosity method is used [12,13,14,15] to simulate the solidification process of the PCM due to its ability resolve explicit tracking of the solid-liquid interface position as well as ease to solve issues related to the phase change [16]. This method affords the exact simulation results and the best image of the required operations.…”

“… There is no explicit requirement for the solid/liquid interface.  All researchers depend on it now [12,13,14,15]. Numerical models were used to simulate the cases of the present study, passing through four steps which are:…”