• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1213-1218
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• 2006

In this study, a numerical model for a vapor compression refrigeration system using MPCM slurries as a secondary fluid through an evaporator was developed, and the system performance was compared with that using water Generally, the MPCM system showed higher performance than the water system. The COP of the MPCM system was higher by 16.6 to 18.6% than that of the water system at all conditions. The MPCM slurry yields better performance in the aspect of heat transfer and heat transportation comparing to the sensible heat transfer medium such as water.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.3
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• pp.107-113
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• 2009

The objective of this study is to investigate performance characteristics of a household refrigerator using a two-stage compression cycle. The performance of the two-stage compression cycle was measured by varying the compressor speed, condensing temperature, and evaporating temperature. The COP of the two-stage compression cycle was analyzed and then compared with that of the single-stage compression cycle. The optimum combination of compressor speeds for a low- and a high-stage was determined. The COP of the two-stage compression cycle using a PTC (parallel two-stage compression) method was 5.85% higher than that of a STC (serial two-stage compression) method at optimum operating conditions.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.237-244
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• 2018

Objective: Flat-footed people struggle with excessive ankle joint motion during walking and running. This study aimed to investigate the effects of customized three-dimensional 3D-printed insoles on the kinematics of flat-footed people during daily activities (walking and running). Method: Fifteen subjects (height, $169.20{\pm}2.61cm$; age, $22.87{\pm}8.48years$; navicular bone height, $13.2{\pm}1.00mm$) diagnosed with flat feet in a physical examination participated in this study. Results: The customized 3D-printed insoles did not significantly affect 3D ankle joint angles under walking and running conditions. However, they shifted the trajectory of the center of pressure (COP) laterally during fast walking, which enhanced the load distribution on the foot during the stance phase. Conclusion: The customized 3D-printed insoles somewhat positively affected the pressure distribution of flat-footed people by changing the COP trajectory. Further research including comparisons with customized commercial insoles is needed.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.77-82
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• 2020

In this paper, we developed a cooling system for the refrigeration truck using natural carbon dioxide refrigerant which is attracting attention as an environmentally-friendly refrigerant. We developed a high efficient environmentally-friendly refrigerated truck that converted the existing diesel vehicle into an LNG vehicle to improve emissions of truck and improved the efficiency of the cooling system by utilizing a heat of LNG vaporization. The COP of refrigerated truck system was increased 144%.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.135-135
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• 1999

• Nuclear industry
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• v.36 no.3
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• pp.58-61
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• 2016

지난해 12월 기후변화협약 당사국총회에서 기후 변화 문제에 대한 국제적인 합의를 이룬 것을 두고 전 세계 에너지산업계는 역사적인 이정표를 세운 쾌거라고 환영하였다. 그런데 이번 합의는 원전산업에 과연 어떤 의미가 있는 것일까?

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.27-35
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• 2003

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.359-359
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• 2002

• Proceedings of the Korean Society of Potoscience Conference
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• 2005.06a
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• pp.36-36
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• 2005

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1028-1034
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• 2005

The objective of this paper is to study the effects of the cooling air mass flow rate and the heat input variation by the simulation and the experiment. An air-cooled $NH_3/H_2O$ absorption chiller is tested in the present study. The nominal cooling capacity of the single effect machine is 17.6 kW (5.0 USRT). The overall conductance (UA) of each component, the cooling capacity, coefficient of performance and each state point are measured with the variation of the cooling air mass flow rate and the heat input. It is found that the COP and cooling capacity increase and then decreases with increasing the heat input. It is also found that the COP and the cooling capacity increase and keep constant with increasing the cooling air mass flow rate. The maximum COP is estimated as 0.51 and the optimum cooling air mass flow rate is $217\;m^3/min$ from the present experiment.