This study proposes a 3-dimensional (3D) mathematical model to simulate the heat transfer process in a
direct contact latent heat thermal energy storage (TES) tank for conventional air-conditioning systems.
The thermal performance, including the congealing point and congealing latent heat of a new phase
change material (PCM), which is developed for use in conventional air-conditioning systems with a direct
contact TES tank, is studied. To improve the charging performance of direct contact TES system and
further understand the freezing process, a 3D numerical model was developed in ANSYS FLUENT. The
volume of fluid (VOF) method tracked the volume fraction of each of the phases. The Navier-Stokes
equations were solved using a finite-volume formulation, and energy equation was modeled by using an
enthalpy-based formulation. The method provided a comprehensive model of the dynamic and thermal
aspects of the impact process. To validate the analytical model an experimental cool storage airconditioning system with a direct contact TES tank was designed and setup. The effects of the heat
transfer fluid (HTF) inlet temperature, the flow rate of the liquid PCM, the complete charging time, cold
storage capacity of the direct contact storage tank and distribution of temperature in the direct contact
cold storage device were investigated. The results indicate that the charging capacity increases more
rapidly when the PCM flow rate is greater. The complete charging time can be reduced by increasing the
flow rate of the liquid PCM and decreasing inlet temperature of the HTF when charging the same quality
of PCM. The charging capacity is larger with a lower HTF inlet temperature, however, changing the HTF
inlet temperature does not appreciably change the total storage capacity.
© 2015 Elsevier Ltd. All rights reserved
This study proposes a 3-dimensional (3D) mathematical model to simulate the heat transfer process in adirect contact latent heat thermal energy storage (TES) tank for conventional air-conditioning systems.The thermal performance, including the congealing point and congealing latent heat of a new phasechange material (PCM), which is developed for use in conventional air-conditioning systems with a directcontact TES tank, is studied. To improve the charging performance of direct contact TES system andfurther understand the freezing process, a 3D numerical model was developed in ANSYS FLUENT. Thevolume of fluid (VOF) method tracked the volume fraction of each of the phases. The Navier-Stokesequations were solved using a finite-volume formulation, and energy equation was modeled by using anenthalpy-based formulation. The method provided a comprehensive model of the dynamic and thermalaspects of the impact process. To validate the analytical model an experimental cool storage airconditioning system with a direct contact TES tank was designed and setup. The effects of the heattransfer fluid (HTF) inlet temperature, the flow rate of the liquid PCM, the complete charging time, coldstorage capacity of the direct contact storage tank and distribution of temperature in the direct contactcold storage device were investigated. The results indicate that the charging capacity increases morerapidly when the PCM flow rate is greater. The complete charging time can be reduced by increasing theflow rate of the liquid PCM and decreasing inlet temperature of the HTF when charging the same qualityof PCM. The charging capacity is larger with a lower HTF inlet temperature, however, changing the HTFinlet temperature does not appreciably change the total storage capacity.© 2015 Elsevier Ltd. All rights reserved
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