• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.210-211
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• 2013

냉동차량은 이동 또는 정차 중에도 냉동 부하에 일정 온도를 유지 시켜야한다. 종전의 상용차량에 냉동시스템은 차량의 엔진과 연계하여 압축기를 구동하거나 엔진과 연계된 발전기의 전력을 이용하여 일정 온도를 유지하였다. 이러한 방식은 제어가 쉽지 않고 효율이 낮은 단점을 가지고 있다. 본 논문에서는 이러한 단점을 개선하고자 냉동차량이 정차 중인 무시동 기관에서도 일정 온도를 유지 할 수 있도록 센서리스 제어방식이 적용된 3상 인버터를 제안하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.267-272
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• 2004

In this paper a new intelligent diagnostic system for a refrigerator used for a cold-storage of farm produce was propose. It is verified that the developed system is useful for the fault observation and diagnose of a refrigerator by experimental implementation. The basic idea of the proposed system in that the temperature of major pipes at fault status differs from those at normal status. In order to realize the proposed system, the temperature measuring system and diagnostic program were developed.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.98.1-98.1
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• 2015

G-M극저온냉동기의 구동으로 인해 발생되는 크라이오 펌프의 진동 저감을 위해 각 요소에 해당하는 부품의 소재 및 모델 변경으로 설계에 반영하고자 한다. G-M극저온냉동기는 헬륨냉매를 사용하여 2개의 정압과정과 2개의 정적과정으로 구성되는 냉동사이클을 구성하는데, 구조적 특성상 내부 왕복기의 운동과 고저압변환에 따른 압력차이가 냉동기의 진동을 유발하므로 진공성능에 영향을 줄 수 있으므로, 이를 최소화하는 기술 개발이 필요하다. 헬륨냉매의 고압 유동에 따른 관로 압력증가로 인한 유동소음이 발생하는데, 이로 인한 소음을 줄이기 위해 관로의 최적화 설계/방진구조반영(DAMPER)으로 진동 안정화(Vibration Stabilization)설계를 수행 하고자 하며, 이에 따른 최적화 연구을 수행하고자 한다. 일차적으로, 기존 시스템의 진동측정을 통해 진동의 가진원을 밝히고 진동 전달경로를 파악하고자한다. 진동 가진원의 가진 최소화, 진동전달경로의 전달률 최소화, 고압유동에 따른 관로 설계 최적화를 진동해석, 탄성체 동역학해석, 그리고 유동해석을 통해 진동 및 소음의 최소화 방안을 도출하고자 한다. 해석결과를 토대로 진동가진원의 최소화를 위한 제품설계변경과 진동전달경로에 대한 방진을 위한 dmper 적용(전달률 최소화) 및 유동소음 최소화를 위한 damper나 관로 최적화 설계를 수행한다. 상기 기존시스템 측정/분석, CAE해석을 통한 진동/소음의 최적화방안도출 및 실제품 적용기술은 저진동 크라이오펌프 개발을 위한 기반 기술 확립에 크게 기여할것이며, 향후 크라이오펌프 고도화 및 최신 기술 제품 개발에 큰 기여가 기대된다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.304-310
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• 2001

A numerical model which simulates the heat and mass transfer processes within a counter-current plate type generator for ammonia/water absorption refrigerators was developed. Ammonia/water solution flows downward under gravity and ammonia/water vapor generated by flow boiling flows upward. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phase were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the generator length, the wall temperature and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1015-1019
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• 2007

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Because vibration diagnosis can avoid sudden breakdown of machine and reduce the maintenance costs. In chemical factory, Air-compressor and refrigerator which can affect the performance and capacity of output is important machine. Therefore, in this paper, the vibration of reassembled air-compressor and refrigerator after explosion is measured for checking the machine condition. The result of diagnosis and solution is discussed in this paper.

• Journal of Power System Engineering
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• v.12 no.4
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• pp.52-56
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• 2008

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Because vibration diagnosis can avoid sudden breakdown of machine and reduce the maintenance costs. In chemical factory, Air-compressor and refrigerator which can affect the performance and capacity of output are important machine. Therefore, in this paper, the vibration of reassembled air-compressor and refrigerator after explosion is measured for checking the machine condition. The result of diagnosis and solution is discussed in this paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.1034-1041
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• 2001

A numerical model which simulates the flow boiling process of the ammonia/water solution within a plate type generator for ammonia/water absorption refrigerators was developed. The ammonia/water solution flows downward under gravity and the ammonia/water vapor generated by flow boiling flows upward. The heating medium flows counter to the ammonia/water solution. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phases were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the heating medium inlet temperature, the mass flow rate of the heating medium and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.10
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• pp.844-853
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• 2002

A dynamic model which simulates the coupled heat and mass transfer within a vertical tube absorber was developed. The liquid film is a binary mixture of two components, and both of these components are present in the vapor phase. The pressure, concentration, temperature and mass flow rate of the vapor are obtained by assuming that the pressure is uniform within an absorber. The model was applied to an absorber for an ammonia/water absorption refrigerator. The transient behaviors of the pressure, the outlet temperature and the concentration of the solution and the cooling water outlet temperature on a step change at the absorber inlet of the cooling water temperature, the vapor mass flow rate and the concentration of the solution were shown.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.36-41
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• 2008

Fault detection and diagnosis(FDD) system is beneficial in equipment management by providing the operator with tools which can help find out a failure of the system. An experimental study has been performed on fault detection and diagnosis method for a water chiller. Bayes classifier, which is one of classical pattern classifiers, is adopted in deciding whether fault occurred or not. FDD algorithm can detect refrigerant leak failure, when 20% amount of charged refrigerant for normal operation leaks from the water chiller. The refrigerant leak failure caused COP reduction by 6.7% compared with normal operation performance. When two kinds of faults, such as a decrease in the mass flow rate of cooling water and temperature sensor fault of cooling water inlet, are detected, COP is a little decreased by these faults.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.4
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• pp.137-144
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• 2016

Commercial buildings account for a significant proportion of the total building energy use in Korea, and cooling energy, in turn, accounts for the largest proportion of total energy consumption in commercial buildings. Under this circumstance, chiller staging is considered to be a reasonable and practical solution for cooling energy saving. In this study, the part-load ratio and the operating characteristics of a vapor compression chiller were analysed within an office building. In addition, energy consumption among different chiller staging schemes was comparatively analysed. As a result, significant proportions of total operating hours, cooling load and energy consumption turned out to be in the part load ratio range from 0% through 50%, and thus energy consumption was significantly affected by the chiller COP at low part-load conditions, indicating that the chiller operation at the part-load is an important factor in commercial buildings. In addition, utilizing a sequential chiller staging scheme can reduce the annual cooling energy usage by more than 10.3% compared to operating a single chiller.