• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.91-91
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• 1999

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.4
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• pp.451-462
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• 1996

In this study, which focuses on ice storage, a fundamental study in cooling and solidification was performed, including the interesting phenomena of density inversion, supercooling and dendritic ice. A numerical study was performed for natural convection and ice formation considering existence of subcooling and dendritic ice were analyzed numerically by using finite difference method and boundary fixing method. In the mesh, the solid fraction was introduced with adding as a term to the energy conservation equation. A flow in the dendrite was modelled as a flow in a porous medium, and the momentum conservation equation was modified to incorporate resistance forces involved in flows through porous media. A numerical solution of the time dependencies of dendrite area and dense ice front was successfully obtained, and the numerical results were good agreement with experimental results. Based on this methodology, a discussion was made of phenomena and characteristics of cooling and freezing processes under various conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.24-35
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• 1997

Melting process inside in a vertical cylinder has been investigated numerically to observe heat transfer characteristics in the latent heat storage vessel applied to the thermal storage system. The time-dependent boundary fitted coordinate system was introduced to overcome the difficulty caused by the moving boundary. The present results are in good agreement with the available previous data when the initial subcooling effect of the solid phase is not considered. It is found that the melting is promoted by the natural convection, but is delayed by the initial subcooling effect of the solid phase.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.2079-2087
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• 1993

The effects of subcooling and natural convection are studied numerically on the melting process of an initially subcooled phase-change medium filled inside a horizontal circular cylinder. It is postulated that melting continues with the tube wall kept at a constant temperature and with the unmelted solid core fixed. Primary emphasis is placed on the evolution of interface morphology, the local/overall heat transfer rate at the tube wall and at the interface, and the structure of natural convection. The numerical results are mainly presented in terms of the Rayleigh and subcooling numbers. As the degree of subcooling intensifies, the melting rate and the movement of the interface are impeded but the interfaces are of similar shape with the passage of time. The heat transfer characteristics are found to be mostly governed by the formation pattern of natural convection in the liquid phase. Good agreement with available experimental data is found.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.70-76
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• 2003

An experimental study was performed to understand the heat transfer and fluid dynamic characteristics of Sub-Cooled Hybrid Condenser (SCHC), which conventional condenser and receiver dryer are integrated into. SCHC also employs a sub-cooled refrigerant passages at the end of the condenser in order to supply perfect liquid refrigerant to the expansion unit. Throughout the present study, it was found that the developed SCHC increases in the degree of sub-cooling by 10~100% compared to conventional condenser. The excessive sub-cooling has improved the cooling performance by 10%, and that leads reduction in evaporator outlet air temperature by $1.5^{\circ}C$. Also found through the study is that the refrigerant pressure drop across SCHC is fairly increased due to insertion of the desiccant cartridge in the receiver tank which is composed of zeolite, filter and supporter plate.

• Journal of Powder Materials
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• v.13 no.6 s.59
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• pp.387-395
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• 2006

본고에서는 고유한 원자구조에 기인한 우수한 특성으로 인해 구조재료 및 기능재료로서 그 활용이 기대되고 있는 벌크 아몰퍼스 소재에 있어 온간압출, 온간압연, 방전 플라즈마 소결(Spark Plasma Sintering)등 과냉각액체온도구간에서의 점성유동을 이용한 고화성형 공정의 최근 기술동향에 대해 간략히 소개했다.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.143-149
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• 1999

In this study , the new method which is used by magneticfluid for undercooling ends and continuous ice making is introduced to ice making in the ice stroage system and its validity is studied experimentally . This study made sure how shape control of magniticfluid and instant explosure method can effect on the undercooling degree and it exchange by time change at the moments of undercooling ends and acquired the fundamental knowledge for control method about undercooling ends.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.205-210
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• 2004

Sub-cooled hybrid condenser(SCHC) which have been developed through this study is an appliance of integrating a condenser with a receiver dryer, which were previously separated. It is supposed that the development of sub-cooled hybrid condenser will be able to reduce not only weight, size, production process and cost, but also quite improve in capability, which will be of great use for the technological development and research of an air conditioning system whose importance is higher in a car. Through the present study it was found that the developed SCHC increases in the degree of sub-cooling by 10∼100% compared to conventional condenser. The excessive sub-cool has improved the cooling performance by 10%, and that leads to the reduction in evaporator outlet air temperature $1.5^{\circ}C$. Additionally, it is expected that sub-cooled hybrid condenser weights less by 100g than the previous condensers which has equal super heat.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.85-92
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• 2014

This study carried out experimental on the cooling characteristics of clathrate compound including TMA(Tri-Methyl-Amine ; $(CH_3)_3N$) as a low temperature latent heat storage material. And additive was used for subcooling improvement of TMA-water clathrate compound. The conclusion of above study is as following ; TMA 25wt%-water clathrate compound is shown stable phase change and low subcooling degree. The subcooling was improved in the case ethanol($CH_3CH_2OH$) 0.5wt% is added to TMA 25wt%-water clathrate compound.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.11a
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• pp.225-228
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• 2003