• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.6 s.261
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• pp.574-580
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• 2007

The objective of this article is to present an analysis of all heat transfer paths through the energy nose under closed door conditions when refrigeration system of household refrigerator-freezer is operating on. Both experimental and numerical methods are suggested as a means of determining the overall energy nose load amount as well as the load due to each pathway such as mullion section and F and R sides of the household refrigerator-freezer. In other words, all loads determined in this article are just energy nose and not the loads seen by the refrigeration system. We suggest good ideas for improving the heat transfer losses such as conduction and convection through the energy nose. As we can be known from the experimental test results, it is effective to prevent the heat loss of a mullion section. And energy efficiency is also decreased approximately 6% compared to that of a baseline sample test result. As we can be known from the Ansys 8.1 analysis, it is shown the steady state temperature distribution in figures from 6 to 8. And the direction of the heat flow through the energy nose section is also easily seen from that In conclusion, the article is focused on an energy nose section in household refrigerator-freezer for practical proposes which is the energy saving in a household refrigerator-freezer. And the method suggested may be applied to any make or model to aid in the search for high efficient energy nose section of household side by side refrigerator-freezer as well as top mounted refrigerator-freezer, commercial refrigerator and so on.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.2
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• pp.95-102
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• 2003

Optimization for the insulation thickness and external shape of a household refrigerator is peformed in order to minimize thermal load through the insulation wall. The one dimensional conduction heat transfer model is adopted to calculate thermal load. Calculus of variation is employed to optimize the thickness and shape of refrigerator or freezer. The uniform distribution of an insulation thickness and cubed external shape make thermal load minimize. Finally, by using both of the computational and experimental method, the thermal load is minimized for a refrigerator/freezer. It is shown that there exists optimal thickness of insulation walls and external shape for given the external cabinet dimensions and freezer and refrigerator internal volumes, Also, the analytical results are well agreed with the experimental results.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.517-522
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• 2005

A cold storage refrigerator using phase change material(PCM) has been developed and its performance test results are provided here. The inner temperature of the refrigerator is controlled with forced convection driven by a fan using a DC battery. At the first, to freeze all the PCM of the ambient temperature by a built-in refrigerating machine, it took about 8 and 10 hours respectively at the refrigerator and the freezer mode. Then, without external power supply, the inner temperature of the cold storage refrigerator has been maintained at $-18{\pm}1^{\circ}C$ during 14 hours at the freezer mode and maintained at $3{\pm}^{\circ}C$ during 34 hours at the refrigerator mode. Just after the end of its valid usage as a refrigerator or a freezer, it took about 6 hours to refreeze the PCM for its reuse. During the test, the ambient temperature was kept at $30^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.357-366
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• 2018

In this study, if the set temperature of the refrigerator differs from the set temperature of the refrigerator, the temperature distribution of food in the refrigerator is estimated by measuring the temperature in the refrigerator and in the refrigerator room. In addition, based on the set temperature of the refrigerator and the freezer, the temperature range of the heat is large and the time required to recover to the set temperature is to be determined. And the optimal setting temperature for home refrigerators is to be shown by measuring the amount of power consumed to recover to the set temperature. As a result, the conditions in which the temperature in the freezer realized $-18^{\circ}C$ were only appropriate in case 3, Case 6, Case 8, and Case 9 when the set temperature in the refrigerator was lower than that in the freezer. Under these conditions, the minimum temperature in the refrigerator was $-1.1^{\circ}C$, Case 6 was $-1.5^{\circ}C$, Case 8 was $-1.1^{\circ}C$ and Case 9 was $-0.8^{\circ}C$, respectively. Also, the total power consumption during the 10 hours operation time of each case was greater than the setting temperature of the freezer and the refrigerator except case 4, since case 4 started operation around 13:30 in the morning.

• The Korean Journal of Food And Nutrition
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• v.28 no.5
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• pp.918-925
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• 2015

An investigation was conducted to evaluate the hygienic status of 33 high school foodservice systems in Yongin city by using hygiene management guide checklist, ATP bioluminescence assay and microbe inspection petrifilm (APC, coliform group, Staphylococcus aureus) of food utensils during use. The 22 hygiene management guide checklist items about facilities, personal hygiene, food control, distribution, washing and disinfection had good grade but there were some inadequate behaviors on observation. The inspection results showed their sanitary condition met the level B of the recommendation of Korea method, it means sanitary management system get settled but more practical CCP system was needed. ATP bioluminescence assay was conducted on surface of food facilities, ATP ranged 425~2,552 RLU on gloves, 541~70,251 RLU on apron, 1,596~88,490 RLU on working desk, 1,177~263,813 RLU on sterilizer grip, 715~32,814 RLU on sterilizer shelf, 114~619,725 RLU on refrigerator grip, 677~319,007 RLU on refrigerator shelf, 71~196,725 RLU on freezer grip, 1,535~233,375 RLU on freezer shelf. APC ranged $66.7{\pm}29.0CFU$ on freezer grip, $102.1{\pm}35.9CFU$ on refrigerator grip, $45.4{\pm}28.2CFU$ on heating cabinet grip, $58.8{\pm}40.4CFU$ on sterilizer grip, the number of coliform group ranged $5.6{\pm}4.9CFU$ on freezer grip, $9.1{\pm}8.7CFU$ on refrigerator grip, $1.2{\pm}1.1CFU$ on heating cabinet grip, $4.5{\pm}4.4CFU$ on sterilizer grip. S. aureus ranged $8.0{\pm}5.6CFU$ on freezer grip, $12.2{\pm}9.6CFU$ on refrigerator grip, $2.1{\pm}1.6CFU$ on heating cabinet grip, $11.6{\pm}6.4CFU$ on sterilizer grip.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.686-691
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• 2000

Animation technique from the PIV database is particularly emphasized to give macroscopic and Quantitative description of complex flow fields. As an example, an experimental study was carried out investigate the fundamental (low characteristics of the freezer with the domestic refrigerator. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. Image intensifier CCD camera to cope with illumination problem is arranged for the accurate PIV measurement of large flow field. As a results, continuous pictures of the spatial distribution of the instantaneous and time-mean velocity distribution are displayed in real-time sense.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.89-96
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• 2020

In this study, we developed a finite element model for the built-in bottom-freezer type refrigerator and then used the structural analysis method to analyze and evaluate the deflection of the doors. We tested the validity of the developed analytical model by measuring the deflection of the hinge when loads were applied to the upper and lower hinges of the refrigerating compartment and compared these with the analysis results. The comparison of the vertical displacement of the measured result and the analysis result showed an error ratio of up to 12.8%, which indicates that the analytical model is consistent. Using the analytical model composed of the cabinet, hinges and doors, we performed analyses for two cases: both doors closed, and the refrigerating door open. Since the maximum vertical displacement of the refrigerating compartment door (R-door) with the food load is smaller than the gap between the lower surface of the R-door and the upper surface of the freezer compartment door (F-door), it is judged that the R-door and the F-door do not contact when the doors are opened or closed. In addition, the analysis result showed that the difference between the vertical displacement at the hinge on the opposite side and the hinge side of the R-door is favorably smaller than the management criterion of the refrigerator manufacturer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.6
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• pp.319-325
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• 2009

The purpose of this study is to investigate the performance characteristics of a bypass two-circuit refrigerator. A bench scale refrigeration system was designed and constructed to estimate possible performance improvement of the bypass two-circuit refrigerator. The experiments were conducted in the bench scale refrigeration system by varying capacity of the condenser and refrigerant charge amount with an adoption of a refrigerant storage vessel. The COPs of the bypass two-circuit refrigeration system in the refrigerator and freezer (RF)-mode and freezer(F) only-mode were increased by 10% and 17%, respectively, with increasing the capacity of the condenser. Besides, the COP of the system in the F only-mode was increased by 10% by adopting the refrigerant storage vessel.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.509-514
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• 2000

A numerical study has been performed to design duct parameters in the freezer of a domestic refrigerator. The visualization results of FDM analysis using the standard k-$\varepsilon$ model with inlet boundary conditions modelled in this paper show good agreements with the experimental ones in prediction overall flow characteristics. Dominant vortex flows are found in the left upper and right lower corners, while there exists large turbulent kinetic energy around the fan and right upper side of the fan. It, in turn, has effects on the performance and noise. It is recommended to locate the outlet far away from the fan in order to reduce the noise level.

• Journal of Power System Engineering
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• v.7 no.2
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• pp.17-22
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• 2003

As side-by-side refrigerators came into existence, there has been a growing concern about the free%ins-up of the vital equipment in a walk-in freezer. Due to a bad performance, customers are experiencing too much frustration. In order to minimize the freezing phenomena, the numerical simulation has been performed on the characteristics of cold air flow in a side-by-side refrigerator. The flow field has been simulated with a standard $k-\varepsilon$ turbulent model and a SIMPLE algorithm based on the finite volume method. Through the results of the analysis of the pattern of cold air flow, finally the shape of outlet for cold air flow was modified. The present model was compared with the modified model. The latter was better than the former in minimizing the freezing phenomena.