• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.459-465
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• 2011

Excessive heat may be generated during the semiconductor manufacturing process. Therefore, precise control of temperature is required to maintain a constant ambient temperature and wafer temperature in the chamber. Compared to an industrial chiller, a semiconductor chiller's power consumption is high because it is in continuous operation for a year. Because of this high power consumption, it is necessary to develop an energy-efficient chiller by optimizing the operation. The competitiveness of domestic products is low because of the high energy consumption. We experimentally investigated a domestic semiconductor by conducting load change, temperature rise and fall, and control precision experiments. The experimental study showed that the chiller had 2.1-3.9 kW of cooling capacity and 0.56-0.93 of EER. The control precisions were ${\pm}1^{\circ}C$ and ${\pm}0.6^{\circ}C$ when the setting temperatures were $0^{\circ}C$ and $30^{\circ}C$ respectively.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.117-125
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• 2005

It is common to find lots of organic and inorganic precipitates inside of industrial cooling system. Analytical instruments including ICP-AES, IC, XRD, and SEM were used to investigate the effects of application of Mg on reaction among coolant, precipitates and suspended matters within chiller system. Magnesium (Mg) has a decreasing effect on total dissolved material in the coolant suggesting a significant improvement of quality of coolant. Disappearance of most organic materials in the cooling devices also suggests an inhibitive effect on the growth of organic matters.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1141-1144
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• 2010

본 연구에서는 난방운전시 저온 및 착상 조건에서 히트펌프 칠러의 성능을 조사하고자 하였다. 실험은 항온항습 기능을 가진 공기엔탈피 방식의 칼로리미터와 항온수조를 사용하여 수행되었으며, 실외온도조건을 설정한 후에 히트펌프 칠러의 성능을 실험으로 측정하였다. 외기조건이 $-7^{\circ}C$에서 $-15^{\circ}C$까지 변화함에 따라 시스템의 성능과 COP는 표준온도 조건의 실험값 보다 약 48~87%까지 감소하였다. 착상 실험에서는 시간 변화에 따라 출구수온이 표준온도를 기준으로 74% 감소하였다. 본 연구로부터 히트펌프 칠러의 설계 기초자료 획득 및 신뢰성을 확인할 수 있었다.

• Journal of the Korean Institute of Gas
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• v.24 no.1
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• pp.33-40
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• 2020

Chiller systems which have better temperature stability than Direction expansion coils are often used as condensing units in HVAC systems for offshore plants. Large capacity compressors and electronic expansion valves in chiller systems are mostly imported, and the size of a chiller system depends on heat exchangers such as evaporators and condensers which are locally produced. Due to limited space in the offshore plants, shipyards are demanding manufacturers to make equipment compact. In this paper, a shell & tube heat exchanger, which is used as an evaporator in the conventional flooded chiller system, is replaced by a newly developed compact plate & shell heat exchanger. The main development process of the plate & shell heat exchanger is introduced, and its performances were experimentally evaluated with a real flooded chiller system, and the results are presented.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1123-1126
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• 2010

본 연구에서는 외기온습도에 따른 히트펌프 칠러의 난방성능을 조사하고자 하였다. 난방표준 온도조건에서 건구온도 및 습구온도 변화에 따른 히트펌프 칠러의 난방능력과 COP를 획득하기 위하여 항온항습 챔버와 항온수조를 사용하였다. 실험은 건구온도 $7^{\circ}C{\sim}17^{\circ}C$, 상대습도 67%~87%에서 수행하였다. 외기온도가 증가함에 따라 난방능력은 약 27%, COP는 약 28% 증가하였지만, 상대습도 증가에 따른 난방능력과 COP의 변화는 거의 없었다. 따라서 난방운전 시 건구온도의 영향은 크고, 상대습도의 영향은 미미함을 알 수 있었다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.538-539
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• 2012

수냉형 인버터는 냉각 시 칠러를 사용하게 되는데 칠러는 입력 냉각수의 온도가 높을수록 열교환 효율이 높아져 소비전력이 감소한다. 하지만 인버터는 입력 냉각수의 온도가 높을수록 손실이 증가하게 되므로 수냉형 인버터는 각각의 출력 부하에 따라 최대 효율 점이 존재한다. 본 논문에서는 각각의 출력 부하에서 냉각수 온도 제어를 통해 수냉형 인버터의 최대 효율점을 추적하는 방법을 제안한다.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2005.05a
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• pp.11-13
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• 2005

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.11
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• pp.592-604
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• 2017

A chiller, having a thermal storage system, can contribute to load-leveling and can reduce the cost of electricity by using electricity at night. In this study, the control experiments and simulations are conducted using both conventional and advanced methods for the building cooling system. Advanced approaches, such as the "region control method", divide the control region into five zones according to the size of the building load, and determines the cooling capacities of the chiller and thermal storage. On the other hand, the "dynamic programming method" obtains the optimal cooling capacities of the chiller and thermal storage by selecting the minimum-cost path by carrying out repetitive calculations. The "thermal storage priority method" shows an inferior chiller performance owing to the low-part load operation, whereas the chiller priority method leads to a high electric cost owing to the low utilization of thermal storage and electricity at night. It has been proven that the advanced control methods have advantages over the conventional methods in terms of electricity consumption, as well as cost-effectiveness. According to the simulation results during the winter season, the electric cost when using the dynamic programming method was 6.5% and 8.9% lower than that of the chiller priority and the thermal storage priority methods, respectively. It is therefore concluded that the cost of electricity utilizing the region control method is comparable to that of the dynamic programming method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1285-1292
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• 2011

The characteristics of a semiconductor chiller system with EEV have been experimentally studied. Three experiments on temperature changes (increase and decrease), load variation, and control precision were conducted to investigate the operating characteristics of the semiconductor chiller. The power consumption was 8.9 kW during increase in temperature. The required time was 37.5 min for CH1 and 39.5 min for CH2. Moreover, the time required for falling temperature was 26.5 min. The control precision for partial load operation was relatively low compared to that of a full load operation. In addition, the CH2 equipped with a step motor showed better control precision. The power consumed by the chiller for process cooling water was 1.8 kW, which was one-half of that consumed during the refrigeration cycle. The objective of this study is to provide an optimal control guideline for the semiconductor chiller design.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.11
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• pp.760-766
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• 2010

Excessive heat occurs during semiconductor manufacturing process. Thus, precise control of temperature is required to maintain constant chamber-temperature and also wafer-temperature in the chamber. Compared to an industrial chiller, semiconductor chiller's power consumption is very high due to its continuous operation for a year. Considering the high power consumption, it is necessary to develop an energy efficient chiller by optimizing operation control. Therefore, in this study, a semiconductor chiller is experimentally investigated to suggest energy-saving direction by conducting load change, temperature rise and fall and control precision experiments. The experimental study shows the cooling capacity of dual-channel chiller rises over 30% comparing to the conventional chiller. The time and power consumption in the temperature rising experiment are 43 minutes and 8.4 kWh, respectively. The control precision is the same as ${\pm}1^{\circ}C$ at $0^{\circ}C$ in any cases. However, it appears that the dual channel's control precision improves to ${\pm}0.5^{\circ}C$ when the setting temperature is over $30^{\circ}C$.