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]