Thermal energy storage got a significant role in the solar energy conservation in order to expand... more Thermal energy storage got a significant role in the solar energy conservation in order to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) is used in this kind of systems in order to store a great amount of thermal energy. In fact, Latent heat storage in a PCM is very interesting because of its high-energy storage density and its isothermal behavior during the phase change process. Hence, heat accumulated during sunshine period, can be restituted to be used for air conditioning purposes in buildings. In this perspective, we propose in this work a numerical study based on an enthalpy formulation to investigate the solidification of a PCM in a heat exchanger with and without fins. This numerical approach gives simultaneously the temperature distributions in the PCM storage system and temporal propagation of the solidification front during the solidification of the PCM when it is exposed to a cold air flow....
Thermal energy storage got a significant role in the solar energy conservation in order to expand... more Thermal energy storage got a significant role in the solar energy conservation in order to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) is used in this kind of systems in order to store a great amount of thermal energy. In fact, Latent heat storage in a PCM is very interesting because of its high-energy storage density and its isothermal behavior during the phase change process. Hence, heat accumulated during sunshine period, can be restituted to be used for air conditioning purposes in buildings. In this perspective, we propose in this work a numerical study based on an enthalpy formulation to investigate the solidification of a PCM in a heat exchanger with and without fins. This numerical approach gives simultaneously the temperature distributions in the PCM storage system and temporal propagation of the solidification front during the solidification of the PCM when it is exposed to a cold air flow. Also, we give in this study the transient evolution of the longitudinal air temperature profiles. Nomenclature dt time step Tair temperature of air at node, K Cp air heat capacity of air, J. K-1 .kg-1 h heat transfer coefficient W.m-2 .K-1 w air velocity, m.s-1 T 0 inlet air temperature ex width of the computational domain ey thickness of the computational domain ez length of the computational domain X,Y,Z dimensionless coordinates system i width index j thickness index k lengh index Cp(T) heat capacity per unit volume including the phase change, J.m-3 .K Cp s solid phase heat capacity per unit volume, J.m-3 .K Cp l liquid phase heat capacity per unit volume, J.m-3 .K L latent heat, J.kg-1
The thermal energy storage got a significant role in the solar energy conservation to expand its ... more The thermal energy storage got a significant role in the solar energy conservation to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) used in this kind of systems in order to store a great amount of thermal energy. This work concerns the solidification in the presence of the natural convection of a rectangular phase change material exposed to a cold airflow along the conducting sidewalls. With this intention, the first stage includes the presentation of a numerical model based on the conservation equations, treated by finite volume method. This numerical approach aims to follow the evolution of the various parameters characterizing the phenomenon of phase change (liquid-solid interface and solid fraction) during all the processes of solidification as well as the temperature and the velocity distribution in the PCM storage systems. Moreover, this study presents the transient evolution of the longitudinal air temperature profiles. It also presents the effect of fins number on heat transfer enhancement and the temporal evolution of the solid-ification front. The advantage of this study is to find a solution to extract the maximum of heat during the solidification of the PCM. This solution is to take into account the natural convection and also the addition of the fins.
Thermal energy storage plays a significant role in a large variety of industrial, commercial and ... more Thermal energy storage plays a significant role in a large variety of industrial, commercial and residential applications. Phase change material (PCM) is used in these systems in order to store heat. Latent heat during phase change material (PCM) melting is one of the most promising for energy storage because of its high-energy storage density and isothermal behavior during the phase change process. The present work is interested in the PCM (Paraffin n-C18) solidification in a thermal storage tube with internal and external horizontal fins for air conditioning systems in the presence of natural convection. A numerical model based on the continuity, momentum and thermal energy equations treated by finite volume method is presented in this paper. This numerical approach aims at studying the impact of thermal convection and fin number on the solidification time of PCM.
Cette recherche a pour but de comprendre le comportement
face à l’eau de mer de structures en bét... more Cette recherche a pour but de comprendre le comportement face à l’eau de mer de structures en béton renforcées de PRFV afin de rassurer les entreprises de génie civil amenées à employer ce type de barres. L’étude s’articule autour d’un programme de collaboration entre le laboratoire de Génie Civil (LGC) de l’École Nationale d’Ingénieurs de Tunis (ENIT) et le Centre de Recherche de la Compagnie Baden en Allemagne (CRCB). Cette recherche s’intéresse à l’application et l’amélioration des matériaux composites dans le domaine du BTP et surtout dans les ouvrages maritimes exposés à un degré d’agressivité élevé. Cette étude devrait contribuer à développer l’usage des barres en composite du fait de leur bonne durabilité dans les milieux marin.
The use of Phase Change Material (PCM) improves the thermal storage capacity of Solar Thermal Acc... more The use of Phase Change Material (PCM) improves the thermal storage capacity of Solar Thermal Accumulators because of its high energy storage density as latent heat, during SolideLiquid phase changes at constant temperature. The present work is interested in the PCM (Paraffin C18) solidification in thermal storage coaxial tubes with internal and external horizontal fins for conditioning systems with two air passages. With this intention, the first stage includes the presentation of a numerical model based on the continuity, momentum and thermal energy equations handled by the finite volume method. This numerical approach aims to study the impact of natural convection, occurring in the liquid phase, on the solidification time of PCM and the temporal evolution of the solidification front. This paper also investigates the effect of fins number on heat transfer enhancement.
Thermal energy storage got a significant role in the solar energy conservation in order to expand... more Thermal energy storage got a significant role in the solar energy conservation in order to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) is used in this kind of systems in order to store a great amount of thermal energy. In fact, Latent heat storage in a PCM is very interesting because of its high-energy storage density and its isothermal behavior during the phase change process. Hence, heat accumulated during sunshine period, can be restituted to be used for air conditioning purposes in buildings. In this perspective, we propose in this work a numerical study based on an enthalpy formulation to investigate the solidification of a PCM in a heat exchanger with and without fins. This numerical approach gives simultaneously the temperature distributions in the PCM storage system and temporal propagation of the solidification front during the solidification of the PCM when it is exposed to a cold air flow....
Thermal energy storage got a significant role in the solar energy conservation in order to expand... more Thermal energy storage got a significant role in the solar energy conservation in order to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) is used in this kind of systems in order to store a great amount of thermal energy. In fact, Latent heat storage in a PCM is very interesting because of its high-energy storage density and its isothermal behavior during the phase change process. Hence, heat accumulated during sunshine period, can be restituted to be used for air conditioning purposes in buildings. In this perspective, we propose in this work a numerical study based on an enthalpy formulation to investigate the solidification of a PCM in a heat exchanger with and without fins. This numerical approach gives simultaneously the temperature distributions in the PCM storage system and temporal propagation of the solidification front during the solidification of the PCM when it is exposed to a cold air flow. Also, we give in this study the transient evolution of the longitudinal air temperature profiles. Nomenclature dt time step Tair temperature of air at node, K Cp air heat capacity of air, J. K-1 .kg-1 h heat transfer coefficient W.m-2 .K-1 w air velocity, m.s-1 T 0 inlet air temperature ex width of the computational domain ey thickness of the computational domain ez length of the computational domain X,Y,Z dimensionless coordinates system i width index j thickness index k lengh index Cp(T) heat capacity per unit volume including the phase change, J.m-3 .K Cp s solid phase heat capacity per unit volume, J.m-3 .K Cp l liquid phase heat capacity per unit volume, J.m-3 .K L latent heat, J.kg-1
The thermal energy storage got a significant role in the solar energy conservation to expand its ... more The thermal energy storage got a significant role in the solar energy conservation to expand its use over time. To exploit solar energy continuously, we require a storage energy system. Phase Change Material (PCM) used in this kind of systems in order to store a great amount of thermal energy. This work concerns the solidification in the presence of the natural convection of a rectangular phase change material exposed to a cold airflow along the conducting sidewalls. With this intention, the first stage includes the presentation of a numerical model based on the conservation equations, treated by finite volume method. This numerical approach aims to follow the evolution of the various parameters characterizing the phenomenon of phase change (liquid-solid interface and solid fraction) during all the processes of solidification as well as the temperature and the velocity distribution in the PCM storage systems. Moreover, this study presents the transient evolution of the longitudinal air temperature profiles. It also presents the effect of fins number on heat transfer enhancement and the temporal evolution of the solid-ification front. The advantage of this study is to find a solution to extract the maximum of heat during the solidification of the PCM. This solution is to take into account the natural convection and also the addition of the fins.
Thermal energy storage plays a significant role in a large variety of industrial, commercial and ... more Thermal energy storage plays a significant role in a large variety of industrial, commercial and residential applications. Phase change material (PCM) is used in these systems in order to store heat. Latent heat during phase change material (PCM) melting is one of the most promising for energy storage because of its high-energy storage density and isothermal behavior during the phase change process. The present work is interested in the PCM (Paraffin n-C18) solidification in a thermal storage tube with internal and external horizontal fins for air conditioning systems in the presence of natural convection. A numerical model based on the continuity, momentum and thermal energy equations treated by finite volume method is presented in this paper. This numerical approach aims at studying the impact of thermal convection and fin number on the solidification time of PCM.
Cette recherche a pour but de comprendre le comportement
face à l’eau de mer de structures en bét... more Cette recherche a pour but de comprendre le comportement face à l’eau de mer de structures en béton renforcées de PRFV afin de rassurer les entreprises de génie civil amenées à employer ce type de barres. L’étude s’articule autour d’un programme de collaboration entre le laboratoire de Génie Civil (LGC) de l’École Nationale d’Ingénieurs de Tunis (ENIT) et le Centre de Recherche de la Compagnie Baden en Allemagne (CRCB). Cette recherche s’intéresse à l’application et l’amélioration des matériaux composites dans le domaine du BTP et surtout dans les ouvrages maritimes exposés à un degré d’agressivité élevé. Cette étude devrait contribuer à développer l’usage des barres en composite du fait de leur bonne durabilité dans les milieux marin.
The use of Phase Change Material (PCM) improves the thermal storage capacity of Solar Thermal Acc... more The use of Phase Change Material (PCM) improves the thermal storage capacity of Solar Thermal Accumulators because of its high energy storage density as latent heat, during SolideLiquid phase changes at constant temperature. The present work is interested in the PCM (Paraffin C18) solidification in thermal storage coaxial tubes with internal and external horizontal fins for conditioning systems with two air passages. With this intention, the first stage includes the presentation of a numerical model based on the continuity, momentum and thermal energy equations handled by the finite volume method. This numerical approach aims to study the impact of natural convection, occurring in the liquid phase, on the solidification time of PCM and the temporal evolution of the solidification front. This paper also investigates the effect of fins number on heat transfer enhancement.
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Papers by Imen Jmal
face à l’eau de mer de structures en béton renforcées de
PRFV afin de rassurer les entreprises de génie civil amenées
à employer ce type de barres. L’étude s’articule autour
d’un programme de collaboration entre le laboratoire de
Génie Civil (LGC) de l’École Nationale d’Ingénieurs de
Tunis (ENIT) et le Centre de Recherche de la Compagnie
Baden en Allemagne (CRCB). Cette recherche s’intéresse
à l’application et l’amélioration des matériaux composites dans le domaine du BTP et surtout dans les ouvrages maritimes
exposés à un degré d’agressivité élevé. Cette étude
devrait contribuer à développer l’usage des barres en composite
du fait de leur bonne durabilité dans les milieux
marin.
because of its high energy storage density as latent heat, during SolideLiquid phase changes
at constant temperature. The present work is interested in the PCM (Paraffin C18) solidification in thermal
storage coaxial tubes with internal and external horizontal fins for conditioning systems with two air
passages. With this intention, the first stage includes the presentation of a numerical model based on the
continuity, momentum and thermal energy equations handled by the finite volume method. This numerical
approach aims to study the impact of natural convection, occurring in the liquid phase, on the
solidification time of PCM and the temporal evolution of the solidification front. This paper also investigates
the effect of fins number on heat transfer enhancement.
face à l’eau de mer de structures en béton renforcées de
PRFV afin de rassurer les entreprises de génie civil amenées
à employer ce type de barres. L’étude s’articule autour
d’un programme de collaboration entre le laboratoire de
Génie Civil (LGC) de l’École Nationale d’Ingénieurs de
Tunis (ENIT) et le Centre de Recherche de la Compagnie
Baden en Allemagne (CRCB). Cette recherche s’intéresse
à l’application et l’amélioration des matériaux composites dans le domaine du BTP et surtout dans les ouvrages maritimes
exposés à un degré d’agressivité élevé. Cette étude
devrait contribuer à développer l’usage des barres en composite
du fait de leur bonne durabilité dans les milieux
marin.
because of its high energy storage density as latent heat, during SolideLiquid phase changes
at constant temperature. The present work is interested in the PCM (Paraffin C18) solidification in thermal
storage coaxial tubes with internal and external horizontal fins for conditioning systems with two air
passages. With this intention, the first stage includes the presentation of a numerical model based on the
continuity, momentum and thermal energy equations handled by the finite volume method. This numerical
approach aims to study the impact of natural convection, occurring in the liquid phase, on the
solidification time of PCM and the temporal evolution of the solidification front. This paper also investigates
the effect of fins number on heat transfer enhancement.