• International Journal of Air-Conditioning and Refrigeration
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• v.6
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• pp.124-135
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• 1998

A thermodynamic cycle analysis is performed for refrigerator-precooled Linde-Hampson hydrogen liquefiers, including catalysts for the ortho-to-para conversion. Three different configurations of the liquefying system, depending upon the method of the o-p conversion, are selected for the analysis. After some simplifying and justifiable assumptions are made, a general analysis program to predict the liquid yield and the figure of merit (FOM) is developed with incorporating the commercial computer code for the thermodynamic properties of hydrogen. The discussion is focused on the effect of the two primary design parameters - the precooling temperature and the high pressure of the cycle. When the precooling temperature is in a range between 45 and 60 K, the optimal high pressure for the maximal liquid yield is found to be about 100 to 140 bar, regardless of the ortho-to-para conversion. However, the FOM can be maximized at slightly lower high pressures, 75 to 130 bar. It is concluded that the good performance of the precooling refrigerator is significant in the liquefiers, because at low precooling temperatures high values of the liquid yield and the FOM can be achieved without compression of gas to a very high pressure.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.349-358
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• 1999

Thermodynamic cycle analysis has been performed to maximize the liquid amount for various hydrogen liquefaction systems using GM(Gifford-McMahon) refrigerator. Since the present authors' previous experiments showed that the liquefaction rate was approximately 5.1mg/s in a direct contact with a commercial GM refrigerator, the purpose of this study is to predict how much the liquefaction rate can be increased in different configurations and with improved heat exchanger performance. The optimal operating conditions have been analytically sought with real properties of normal hydrogen for the single-stage GM precooled L-H(Linde-Hampson) system, the two-stage GM direct contact system, the two-stage GM precooled L-H system and the two-stage helium GM-JT (Joule-Thomson) system. The maximum liquefaction rate has been predicted to be only about 7 times greater than the previous experiment, when the two-stage precooling is employed and the effectiveness of heat exchangers approaches to 99.0%. It is concluded that the liquefaction rate is limited mainly by the cooling capacity of the current GM refrigerators and a larger scale of hydrogen liquefaction is possible with a greater capacity of cryocooler at 60-70 K range.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.5
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• pp.305-310
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• 2009

The amount of heat loss of a refrigerator through the gasket is nearly 30% of total refrigerator heat loss. In this paper, quantitative evaluation analysis of heat loss through gasket is established with numerical heat transfer analysis. Extending the gasket shape to protect the heat loss from the gasket, power consumption is measured by using real refrigerator in a temperature and humidity chamber and suggest the gasket shape to reduce the heat loss. From the present result of the numerical simulation of heat transfer and experiment with varying gasket shape, we are able to reduce the heat loss about 20-40% by using extended gasket and the power consumption can be reduced about 5%.

• Korean Journal of Computational Design and Engineering
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• v.22 no.1
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• pp.59-69
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• 2017

Internal capacity of a refrigerator is an important indicator for design and purchasing criteria. The components facing the internal space may have holes or gaps between parts. In traditional way, design engineers manually remodeled the parts to fill the holes and the gaps for enclosed boundary of the internal space. Then they calculated internal volume by subtracting the assembly of parts from its enclosing volume. However, filling holes and gaps is not an automated process requiring a plenty of labor and time. In this research, we have developed a voxel-based method to estimate the internal volume of a refrigerator automatically. It starts transforming all components facing the interior space into voxels and fills all holes and gaps automatically by the developed hole-filling algorithm to form a completely closed boundary of the assembly. Then, it identifies the boundary voxels that are facing to the internal voxels with any part of the component. After getting the intersection points between the boundary voxels and the surfaces of components, it generates the boundary surface of triangular facets with the intersection points. Finally, it estimates the internal volume by adding volume of each tetrahedron composed of a triangle of boundary surface and an arbitrary point.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2004.11a
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• pp.179-180
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• 2004

In the information society, individual, enterprise and nation must be equipped with environmment and competence with which they can acquire useful information anytime and anywhere to process and utilize it in required form. Therefore, this study intends to investigate how digital TV, refrigerator and computer are laid out in the residential space in terms of life space, analyze the preference of residents an d forecast the preferred functions of the products to be introduced in the future. To build frame for making questionnaire tool of this survey, 3 households of the first constructor among the top-ranked constructors in the first half of 2004 were chose and in-depth interview was made from April 12 to April 17. On the basis of result of preliminary survey obtained by this process, the questionnaire was revised and supplemented. Targeting those living at the apartment house in Seoul and constructors ranked in top-four in the order of construction of the first half of 2004, I selected 3 households for each group in the range of 30$^{\sim}$40 pyung. Twelve cases were surveyed from April 19, 2004 to June 5, 2004. First, TV will continue playing the role of central entertainment mustering family at one place rather than separating them to each room. Second, in the case of refrigerator, the function is being subdivided, making 2 types, refrigerator and kimchi refrigerator indispensable, which was in just unit in the past Third, while computer was usually placed in the individual bedroom,

• Korean Journal of Clinical Pharmacy
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• v.8 no.1
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• pp.54-58
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• 1998

The stability of ceftriaxone sodium 100 mg/ml in the water for injection was tested at two temperature conditions (refrigerator and room temperature) and two storage containers (vitro and syringe). The stability of each sample was determined by high-performance liquid chromatography while storing for 5 days at room temperature and 27 days at refrigerator. The concentration of ceftriaxone sodium was 100 mg/ml which the hospital usually use as a filling preparation for I.V. push or Y-site injection. There was no significant difference between the storage in vials and syringes. There was no significant difference in the change of concentration until storing the reconstituted ceftriaxone sodium injection for 2 days at room temperature and 14 days at refrigerator. In conclusion, the ceftriaxone sodium 100 mg/ml in the water for injection can be stored in vial or syringe for 2 days at room temperature and 14 days at refrigerator after preparation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.435-438
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• 2005

Until now, a home appliance mostly has revealed physical quantities created by the standpoint of engineers, by using the A-weighted sound pressure level and the sound power. It is, however, obviously impossible to characterize a complex sound with a single number. Many parameters must be considered. In addition to loudness, we must take into account frequency and amplitude variation over time, spectral balance, tonality, and many other attributes. Thus, in this research, the general tendency of consumer psychology was investigated for the refrigerator's sound. The noise from the refrigerator was evaluated by not only the simple sound pressure levels but also the consumer's sense of hearing. And also, in order to improve the quality of sound through the design change, the consumer's evaluation was analysed and related to the engineering quantities. With the several design changes, finally the most silence refrigerator in the world was developed with considering the consumer's hearing of sense.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.12
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• pp.1145-1153
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• 2005

3D-PTV measurement has been carried out for the inner flows of a refrigerator. To visualize the air flows three-dimensionally, a helium bubble generator has been used for the 3D-PTV measurements. Three-dimensional flow field of the refrigerator's compartments have been reconstructed by the results obtained by the 3D-PTV Measurements on the electric power-consumption was also carried out in order to evaluate the improvements of the flow characteristics. It was verified that $3\%$ of power consumption was saved by improving the flow passages and characteristics.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.3
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• pp.284-291
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• 2000

A basic pulse tube refrigerator has been constructed with extensive instrumentation to study the characteristics of the heat exchanger experimentally under the oscillating pressure and the oscillating flow. This paper describes the sequential experiments with the basic pulse tube refrigerator. The experiments were performed for various cycle frequencies under the square pressure wave forms. First, the heat flux was measured through the cycle at the both cold and warm end heat exchangers without the regenerator. In order to enhance the thermal communication capability of the heat exchanger with the gas at low operating frequencies, a unique design of the triangular shape radial fin concept was applied to the heat exchangers. For the fin heat exchanger, the measured heat flux and the calculated heat flux from the two well-known oscillating heat transfer correlations were compared and discussed. Second, the regenerator was added to the pulse tube to make a basic pulse tube refrigerator configuration. The experiment showed the great impact of the regenerator on the temperature and the heat flux profiles. At the warm-end, the cyclic averaged heat flux had its maximum value at the specific operating frequency. The paper presents the explanation of the surface heat pumping effect as well as the experimental data.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.5
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• pp.76-83
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• 2018

A cabinet-door integrated finite element model was constructed for a built-in side-by-side refrigerator with an ice dispenser, and its deformation was analyzed using the ANSYS finite element software. As loads, the food load needed to fill in the cabinet and doors and the thermal load occurring during normal operation conditions were taken into consideration. The door height difference (DHD) and door flatness difference (DFD) between the two doors of the freezing and refrigerating compartments were derived. The DHD and DFD under the assembled condition without applied loads satisfied the acceptance criteria specified by the refrigerator manufacturer. It appeared that the food load increases the DFD slightly. The thermal load tends to increase the differences because of the thermal deformation, especially the DFD, of the cabinet and doors.