• 한국초전도ㆍ저온공학회논문지
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• 제13권2호
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• pp.25-28
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• 2011

A compact phase controller of pulse tube refrigerator is proposed in this paper. Most pulse tube refrigerators available now consist of a long inertance tube and reservoir as the phase controller. The long inertance tube and reservoir present a challenge for compact packaging in some applications. To overcome this disadvantage, the long inertance tube and reservoir are replaced with the compact phase controller consisted of mass, spring and damper in pulse tube refrigerator. This process is achieved using similarity of mechanical, electrical, and acoustic system and the specific configuration of the compact phase controller is designed. From the simulation code in this paper, the performance of pulse tube refrigerator with the designed compact phase controller is confirmed to be comparable to pulse tube refrigerator with the long inertance tube and reservoir.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.159-162
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• 2003

Cooling with easy, reliable cryocooler is highly desirable for the commercial and military application The pulse tube refrigerator has no moving parts at the cold end, so that the mechanical vibration and magnetic noise can be reduced to the low level with higher relaibility and longer lifetime than the Stilting cryocooler. The inertance tube improve the performance of pulse tube refrigerator by providing optimal phase shift between pressure and amss flow rate, and it is easiest to implement at large cooling capacity and high operating frequency. In this study, the performance of the inertance pulse tube refrigerator was investigated by analysis. The results show the influence of the diameter and length of the inertance tube on the performance of the refrigerator.

• 한국유체기계학회 논문집
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• 제14권4호
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• pp.45-51
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• 2011

The kimchi refrigerator is the electronic home appliance which is used for the maturing and a custody of the kimchi. In this paper, performance improvement of fan and duct system for kimchi refrigerator has been studied by using a commercial CFD code. In order to achieve a improved fan performance, three-dimensional computational fluid dynamics and the Design of Experiments method have been applied. Additionally, to know the optimized duct inlet shape with the optimized fan, the overall performances were calculated with various duct inlet shapes. The final fan and duct system for kimchi refrigerator showed improved performance in efficiency and total head compared with the existing model.

• 설비공학논문집
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• 제16권4호
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• pp.390-396
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• 2004

A double-inlet pulse tube refrigerator was fabricated as a U-shape with $\Phi$19.0 mm${\times}$125 mm regenerator packed by #200 stainless steel mesh and $\Phi$12.7 mm${\times}$125 mm pulse tube. A pressure sensor was installed at the inlet of the regenerator and a differential pressure sensor was installed across the bypass. Amplitude of the pulsating pressure was independent of the opening of the orifice and the bypass valves. Helium flow through the orifice and the bypass was calculated based on the measured pressure. Energy loss through the orifice and the bypass was evaluated with the measured pressure and the calculated helium flow rate. The energy loss, which is equivalent to the refrigeration capacity at the cold end of the ideal pulse tube refrigerator, was mainly generated through the orifice. It was proportional to the opening of the orifice valve, but the real refrigerator displayed the best performance at the optimized opening of the orifice valve. This optimized performance of the tested pulse tube refrigerator can be explained by additional refrigeration losses. As an example, the shuttle heat transfer loss of the pulse tube was calculated from the measured experimental data.

• 에너지공학
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• 제21권2호
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• pp.138-143
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• 2012

본 연구는 냉장고 가스켓 주위에서 시간변화에 따른 온도를 측정하여 비정상상태 온도 특성을 규명하기 위해 수행되었다. 가스켓 주위 냉장고 내외부에서의 시간변화 온도 측정을 살펴보면 냉장고의 가동에 따라 주기적인 온도 변화를 관찰할 수 있다. 측정된 온도결과를 보면 열전달 전산해석을 수행하였던 이전의 연구들이 경계조건을 적절히 사용하지 않았기 때문에 이전의 연구결과와 많은 차이를 보여주고 있다. 본 연구에서는 적합한 열전달 전산해석 수행을 위해 실험을 통한 온도 분포를 도출하고 가스켓 주위의 냉장고 내외부의 정확한 열전달 경계조건을 제시하는 것을 목적으로 하여 수행하였다.

• 동력기계공학회지
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• 제15권5호
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• pp.37-42
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• 2011

The normal cooling system of a refrigerator is applied to indirect a cooling methods. But the Kimchi refrigerator is applied to direct the cooling method. Recently when the model was applied to both direct and indirect the cooling methods, the improvement was considerable. With the development of the living standards in Korea, there has been more sensitive dissatisfaction about the taste and the smell of Kimchi. In order to solve these kinds, there is a need to systematic and scientific approach. Based on these, the purpose of this study is to optimize design for improve the storage period of Kimchi refrigerator. In this research, we concentrate on the temperature change and heat transfer characteristics of interior parts of the Kimchi refrigerator due to control cycle of temperature and flow phenomenon of cooling air.

• 한국초전도ㆍ저온공학회논문지
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• 제11권1호
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• pp.55-59
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• 2009

Miniature Joule-Thomson refrigerators have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. The thermodynamic performance of J-T refrigerator highly depends on the hydraulic and heat transfer characteristics of the recuperative heat exchanger. The typical recuperative heat exchanger of the J-T refrigerator has the double helical tube and fin configuration. In this study, effectiveness-NTU approach was adopted to predict the thermodynamic behaviors of the heat exchanger for the J-T refrigerator. The thermodynamic properties from the REFPROP were used to account the real gas effects of the gas. The results show the effect of the operating conditions on the performance of the heat exchanger and refrigerator for the given heat exchanger. The influences of mass flow rate and the supply pressure on the effectiveness of heat exchanger and the ideal cooling capacity are discussed in details.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.286-291
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• 2008

Insulation of refrigerator with gasket material near door becomes the technical point at the aspect of heat loss and energy efficiency. Heat loss of refrigerator through the gasket is nearly 30%. In this paper, quantitative evaluation method of heat loss through gasket in established suggest the method for the improvement of heat loss. To analyze the heat transfer, we have used the common software Fluent that is used to CFD. Because of using the convection coefficient of heat transfer, we have solved only the equation of energy for heat transfer. As a result, we have known that heat loss flows through the heat flux vector and that the heat gathered out of the outside iron plate is transferred inner part through the gasket and ABS, etc. Through the result of the numerical simulation that use sub-gasket, we have known that we are able to reduce the heat loss about $20{\sim}40%$. when we applied that sub-gasket on a real refrigerator, the power consumption had reduced about 4.76%. In addition, when we applied a more improved sub-gasket on a real refrigerator and measured the power of the refrigerator the power consumption does reduce about 3% and we will try to apply the improved sub-gasket on a new models of refrigerator.

• 에너지공학
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• 제23권2호
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• pp.35-41
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• 2014

본 연구는 냉장고의 냉장실과 냉동실 사이에 있는 멀리언부의 가스켓 주위의 열전달 해석을 수행하여 이 부분에서 열손실을 크게 하는 구조물인 구조보강용 철구조물 유무에 따른 전산해석을 통한 열전달 해석과 이의 결과에 대한 검증을 위해 냉장고 내부 벽면의 온도를 측정하여 열손실 분석을 통한 냉장고 열손실을 개선하는 것을 목적으로 하였다. 본 연구를 통해 철구조물이 있는 경우에 이를 통하여 고온의 Hotline과 외부 공기의 열이 잘 전달되어서 냉장고의 열손실에 크게 영향을 미치는 것을 알 수 있었으며 이를 제거하면 냉장고 열손실이 24.8% 감소하여 철구조물을 제거하는 것이 냉장고 열손실 설계 개선을 크게 향상시킴을 알 수 있었다.

• 한국기계가공학회지
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• 제17권2호
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• pp.30-36
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• 2018

Since the freezer compartment and the refrigerating compartment are located side by side in a side-by-side refrigerator, the problems of the door height difference (DHD) and door flatness difference (DFD) have been constantly raised. Deformation of the cabinet of a built-in side-by-side refrigerator under food and thermal loads was analyzed by the finite element software ANSYS. The DHD and DFD, occurring due to the deformation of the cabinet, evaluated. From the results of the analysis of the cabinet, the 3D CAD software CATIA was used to geometrically translate and rotate the freezing and refrigerating compartment doors, in consideration of the displacement of the hinge fastening point. Then, the coordinates of two points on the upper corner of the doors were determined, and the DHD and DFD were obtained. It found that the thermal load, occurring under normal operation conditions, decreases the door height difference, but increases the door flatness difference. Values of the analyzed DHD and DFD appear smaller than the acceptance criteria used by the refrigerator manufacturer.