A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Numerical investigation of a triplex tube heat exchanger with phase change material: Simultaneous charging and discharging
Graphical abstractComparison of the steady solid-liquid interface for pure conduction model (left half) and combined conduction and natural convection model (right half) for the phase change material.
HighlightsCFD simulation of a PCM inside a triplex tube heat exchanger under SCD was conducted.For internal heating/external cooling, natural convection affected the upper half.For internal cooling/external heating, upward PCM motion affected the entire PCM.The steady liquid fraction was dependent upon the initial PCM condition.The pure conduction model could be applied to the initially melted PCMs under SCD.
AbstractThermal energy storage by phase change materials (PCMs) has received considerable attention in recent years. Its potential application is due to the issue of energy supply and demand time mismatch management. Thus, at the time of energy availability at supply side, it is stored in PCMs so as to be extracted later on when it is needed. However, in order to provide continuous operation, there might be some times that a system needs to be simultaneously charged and discharged. Most studies focused either on charging, discharging, or consecutive charging and discharging process, while limited work has been conducted for the case of simultaneous processes namely: simultaneous charging and discharging (SCD). This study presents the development of a numerical model to study the performance of a triplex tube heat exchanger equipped with a PCM under SCD. Governing equations were developed and numerically solved using ANSYS Fluent v16.2. Based on the solid-liquid interface evolution over time, the effect of natural convection on the heat transfer was investigated, and internal heating/external cooling mode was compared with the internal cooling/external heating for a triplex tube heat exchanger. According to the mode of heating and initial condition of the storage (fully melted or fully solidified), four different cases were compared based on the steady solid-liquid interface. The results indicated that the upward melted PCM motion had a great impact on the process. Interestingly, depending upon the initial PCM condition, different final solid-liquid interfaces were found. Finally, the pure conduction model was compared with combined conduction and natural convection to identify the dominant heat transfer mechanism. It was found that the former could be applied to the initially fully melted PCMs under SCD with small error, but for the initially solidified PCMs neglecting the natural convection would result in unacceptably large error.
Numerical investigation of a triplex tube heat exchanger with phase change material: Simultaneous charging and discharging
Graphical abstractComparison of the steady solid-liquid interface for pure conduction model (left half) and combined conduction and natural convection model (right half) for the phase change material.
HighlightsCFD simulation of a PCM inside a triplex tube heat exchanger under SCD was conducted.For internal heating/external cooling, natural convection affected the upper half.For internal cooling/external heating, upward PCM motion affected the entire PCM.The steady liquid fraction was dependent upon the initial PCM condition.The pure conduction model could be applied to the initially melted PCMs under SCD.
AbstractThermal energy storage by phase change materials (PCMs) has received considerable attention in recent years. Its potential application is due to the issue of energy supply and demand time mismatch management. Thus, at the time of energy availability at supply side, it is stored in PCMs so as to be extracted later on when it is needed. However, in order to provide continuous operation, there might be some times that a system needs to be simultaneously charged and discharged. Most studies focused either on charging, discharging, or consecutive charging and discharging process, while limited work has been conducted for the case of simultaneous processes namely: simultaneous charging and discharging (SCD). This study presents the development of a numerical model to study the performance of a triplex tube heat exchanger equipped with a PCM under SCD. Governing equations were developed and numerically solved using ANSYS Fluent v16.2. Based on the solid-liquid interface evolution over time, the effect of natural convection on the heat transfer was investigated, and internal heating/external cooling mode was compared with the internal cooling/external heating for a triplex tube heat exchanger. According to the mode of heating and initial condition of the storage (fully melted or fully solidified), four different cases were compared based on the steady solid-liquid interface. The results indicated that the upward melted PCM motion had a great impact on the process. Interestingly, depending upon the initial PCM condition, different final solid-liquid interfaces were found. Finally, the pure conduction model was compared with combined conduction and natural convection to identify the dominant heat transfer mechanism. It was found that the former could be applied to the initially fully melted PCMs under SCD with small error, but for the initially solidified PCMs neglecting the natural convection would result in unacceptably large error.
Numerical investigation of a triplex tube heat exchanger with phase change material: Simultaneous charging and discharging
Mastani Joybari, Mahmood (author) / Haghighat, Fariborz (author) / Seddegh, Saeid (author)
Energy and Buildings ; 139 ; 426-438
2017-01-09
13 pages
Article (Journal)
Electronic Resource
English
CFD , computational fluid dynamics , CHTF , cold heat transfer fluid , CCNC , combined conduction and natural convection , COP , coefficient of performance , DHW , domestic hot water , HHTF , hot heat transfer fluid , HTF , heat transfer fluid , NTU , number of transfer units , PC , pure conduction , PCM , phase change material , SCD , simultaneous charging and discharging , TTHX , triplex tube heat exchanger , Triplex tube heat exchanger , Phase change material , Natural convection , Simultaneous charging and discharging , Melting , Solidification
| British Library Online Contents | 2017
| British Library Online Contents | 2017
| British Library Online Contents | 2017