• Journal of the Ergonomics Society of Korea
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• v.26 no.4
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• pp.113-120
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• 2007

Kimchi refrigerator is a specific refrigerator for Kimchi, Korean traditional fermented food. It has been fast popularized since it was developed about ten years ago. In this study, a survey was conducted with 103 female voluntary respondents to understand the customer satisfaction of the Kimchi refrigerator in the aspect of physical use. The respondents showed a high satisfaction for the use of refrigerators. It was, however, shown that they felt highly uncomfortable in using the refrigerator. In particular, the high discomfort was related to the fact that the customer should bend her torso very much to put Kimchi containers into the refrigerator, take them out of it, or clean its inside. Seventy-five percent of the respondents reported the experience of body-part pains and 58.4% of them reported pain experience in the back. It is presumed that these results are highly correlated to the top-cover design of the refrigerator, which is the most popular type to improve its performance of maintaining proper temperature. Therefore, the developers should consider these usability problems related to the refrigerator and try to enhance its usability by adopting ergonomics in the design stage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.4
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• pp.198-203
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• 1987

The basis of all approaches to improve reliability of marine engines exists in analyzing the field data of troubles and failures on marine engines. This paper analyses the data of troubles and failures on marine engines by Principal Component Analysis Method, one of Multivariate Data Analysis Method. The total number of data investigated is 211 and the observation period is 9 years. The analyzed factors are categorized among five groups respectively; electric.automatic control equipments, auxiliary machinery, pipings, refrigerators.air conditioners, and main engine. The failures in main engine are discovered by a definite fact of disorder, on the contrary, the failures in auxiliary machinery, refrigerators and air conditioners are discovered by sensible judgement of the operators.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.4
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• pp.307-316
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• 2008

The objective of this study is to provide numerical and experimental data that can be used to investigate the performance characteristics of a flat plate fin-tube evaporator in household and commercial refrigerators under frosting conditions. Computer simulations with variations of operating conditions such as air inlet temperature, relative humidity, and geometries were performed to find out optimal design parameters of a fin-tube evaporator for household and commercial refrigerators. The tube-by-tube method was used in the simulation and the frost growth model was considered under frosting conditions. The developed analytical model predicted the decreasing rates of heat transfer capacity and air flow rate ratio within ${\pm}$10% compared to the experimental results for a refrigerator under real operating conditions. As a result, the frost thickness at $3^{\circ}C$ & 80% is increased 40% than that of $-3^{\circ}C$ & 80%, and the frost thickness at $3^{\circ}C$ & 90% is increased 30% than that of $3^{\circ}C$ & 60%. Accordingly, the operating time of the evaporator in the refrigerator was reduced with the increase of the decreasing rate of air flow rate ratio at each condition.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.149-154
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• 2013

Food hygiene practices must be maintained from farm to table in order to prevent contamination by microorganisms. This study was conducted to investigate consumer hygiene practices related to the refrigerator storage of meat, including a microbial analysis, monitoring of refrigerator temperatures and consumer surveys of female homeowners in the capital area of Korea. Home refrigerator temperatures were maintained above $5^{\circ}C$ in 26 (19.7%) of the 132 houses investigated. The percentage of the refrigerators with a total microbial count over $10^2\;CFU/100\;cm^2$ was 14.4%. No E. coli, Salmonella spp. or Listeria monocytogenes microbes were detected. However, Staphylococcus aureus was detected in 14 houses (10.6%). The only statistically significant difference in hygiene practices between the non-contamination group and contamination group was in the last time of refrigerator cleaning (p<0.01), as determined by the consumer survey. To improve food hygiene when using a refrigerator, raw materials must be packaged, meat should be stored only on a designated shelf, and cooked foods must be contained to prevent cross-contamination. The refrigerator should be cleaned regularly, at least once a month, and refrigerator thermometers should be monitored below $5^{\circ}C$ in order to keep food safe.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.164-173
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• 2012

To study the applicability of a scroll type compressor to small capacity refrigerators, a R600a scroll compressor with algebraic scroll wrap has been designed. Its size and performance have been compared to a reciprocating type of the same displacement volume. By employing scroll wrap based on algebraic curve, high compression ratio can be accomplished without increasing the wrap angle much so that compact scroll may be obtained. Compared to a reciprocating one, the designed scroll compressor has diameter and height reduced by about 50% and 80%, respectively. By numerical simulation, it has been estimated that the scroll compressor provides 38.6% more cooling capacity than reciprocating type with 8.9% more power consumption, resulting in 27.3% increase in COP for ASHRAE low back pressure condition. With increasing the operating pressure ratio from 9.5 to 15.3, the overall compressor efficiency of the scroll compressor decreases from 72.6% to 65.2%, while that of the reciprocating compressor increases from 55.7% to 59.8%.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.8 s.113
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• pp.797-805
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• 2006

The sound quality characteristics of refrigerator noise in an anechoic chamber and in a real living environment for 30 models of refrigerators were investigated. Subjective evaluation experiments were conducted to determine subjective tolerance level for refrigerator noise. Refrigerator noise was played from a loudspeaker at the position normally occupied by a refrigerator in a real living environment. A nine-point scale was used to measure subjective satisfaction of the sound pressure levels for refrigerator noise. Point 3 on the scale corresponded to a sound pressure level of about 30 dB(A). Seventy percent of the participants were satisfied with this level of refrigerator noise. A semantic differential test was also conducted to evaluate the sound quality of refrigerator noise. From the results of correlation and multiple regression analyses on the psychoacoustical parameters and subjective evaluations of 30 refrigerators, sound quality indices which predict the subjective rating score were proposed.

• Korean journal of food and cookery science
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• v.19 no.2
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• pp.231-240
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• 2003

The purpose of this study was to evaluate the effect of implementing the HACCP system on foodservice establishments. At first, the hygienic conditions were measured by microbiological hazard analyses of the cooking utensils and working areas. In order to solve the detected problems, the HACCP system was implemented, after what was considered a sufficient settlement period following the initial assessment, then microbiological verification was performed again. In relation to the cooking utensils and equipment(kitchen knives, cutting boards, knives for shredding vegetables, refrigerators, baskets, barts, working tables, preparation tables, tungs, dish-clothes and drains) the microbiological inspection on the Total Plate Count, Coliforms, Staphylococcus aureus and Listeria monocytogenes, were conducted with regard to the working areas(working tables, preparation tables, seasoning's shelves, serving tables, drinking water tables, refrigerators, storage rooms and dining tables), the Total Plate Count and Fungi were also examined. According to the microbiological hazard analyses there were many problems, especially with cutting boards, baskets, barts, dish-clothes and sinkballs. However, by introducing the HACCP system, the microbiological hazard levels were able to be controlled and lowered, and the total aerial bacteria in the working areas of the foodservice establishments were detected at levels below 6 CFU/plate.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.1-6
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• 2022

This paper reviews the literature that has been published since 1980s related to cryogenic refrigeration systems for quantum computing. The reason why such a temperature level of 10-20 mK is necessary for quantum computing is that the superconducting qubit is sensitive to even very small thermal disturbances. The entanglement of the qubits may not be sustained due to thermal fluctuations and mechanical vibrations beyond their thresholds. This phenomenon is referred to as decoherence, and it causes an computation error in operation. For the stable operation of the quantum computer, a low-vibration cryogenic refrigeration system is imperative as an enabling technology. Conventional dilution refrigerators (DR), so called 'wet' DR, are precooled by liquid helium, but a more convenient and economical precooling method can be achieved by using a mechanical refrigerator instead of liquid cryogen. These 'dry' DRs typically equip pulse-tube refrigerators (PTR) for precooling the DRs around 4 K because of its particular advantage of low vibration characteristic. In this review paper, we have focused on the development status of 4 K PTRs and further potential development issues will be also discussed. A quiet 4 K refrigerator not only serves as an indispensable precooler of DR but also immediately enhances the characteristics of low noise amplifiers (LNA) or other cryo-electronics of various type quantum computers.

• Progress in Superconductivity and Cryogenics
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• v.9 no.2
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• pp.35-38
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• 2007

A single-stage and two-stage pulse tube refrigerators have been designed for cryopump application. The different diameters of pulse tube and regenerator have been investigated at single-stage pulse tube refrigerator(PTR). Experiments have been performed on single-stage PTR to reach minimum temperature with optimum valve opening at a few frequencies. And the two-stage pulse tube refrigerators have been assembled with tested single-stage pulse tube and tested. When orifice turn is opened to 9 and double inlet is opened to 3 at a single-stage, the lowest temperature of 33.7 K is achieved. The cooling capacity at single-stage is 38 W at temperature of 80 K. A two-stage pulse tube refrigerator has 16.3K at the second stage and 59.7K at the first stage. The cooling capacity achieved is 16.5 W at 80 K, the first stage and 0.6 W at 20 K, the second stage. Some details on the design of pulse tube refrigerator and the experimental apparatus are given.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.373-380
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• 2023

This study surveyed and compared the temperature distribution in domestic refrigerators and freezers used in Korea to determine whether temperature varied according to the location of food storage. We selected 50 people to collect temperature data; among them, 25 measured the temperature of refrigerators, while the remaining measured the temperature of freezers. Consequently, the lowest and highest temperatures measured in domestic refrigerators were found to be -8.2℃ and 15.8℃, respectively, with an average temperature of 3.73℃. The temperature distribution based on internal location was: 5.06±1.69℃ for the door storage compartment, 4.18±1.19℃ for the inside wall surface, and 3.41±1.36℃ for the inner storage box. Significant temperature differences between the top and bottom were only identified at the door storage compartment (P<0.01). Further, the minimum and maximum temperatures measured in the freezer was -30.3℃ and 0.7℃, respectively, with an average temperature of -17.95℃. The temperature distribution based on location was: -17.19±1.68℃ for the door storage compartment, -17.81±1.07℃ for the inside wall surface, and -18.78±1.72℃ for the inside storage box. The results were similar to that of the refrigerator, with the lowest temperature in the inside storage box, and a significant temperature difference between the top and bottom noted only at the door (P<0.01). The maximum temperature difference (between locations) within the refrigerator and freezer was found to be 2.18 and 2.02℃, respectively. In conclusion, the temperature in the entire space was not constant; there were significant deviations at different storage locations. Therefore, public authorities should actively advise customers on the recommended storage locations for each food type. People will benefit from awareness about storage management, including avoiding storage of temperature-sensitive foods in door compartment.