• 한국초전도ㆍ저온공학회논문지
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• 제1권2호
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• pp.54-59
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• 1999

An experimental study was carried out to improve the cooling capacity and performance of the pulse tube refrigerator. Three buffer pulse tube refrigerator was designed and fabricated, and the experimental apparatus operating process of the therr buffer pulse tube refrigerator and results obtained with the performance test. The cooldown characteristics and load characteristics are described. The lowest temperature measured in the three buffer pulse tube refrigerator was 88K and the cooling capacity at the optimum operating condition was 27 W at 120K.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
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• pp.189-193
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• 1999

An experimental study was carried out to improve the cooling capacity and performance of the pulse tube refrigerator. Three buffer pulse tube refrigerator was designed and fabricated, and the experimental apparatus was constructed. This paper presents operating process of three buffer pulse tube refrigerator and results obtained with the performance test. The cooldown characteristics and load characteristics are described. The lowest temperature measured in three pulse tube refrigerator was 88K and the cooling capacity at the optimum operating condition was 27W at 120K.

• 한국수소및신에너지학회논문집
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• 제33권5호
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• pp.534-540
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• 2022

Liquid hydrogen has the best storage capacity per unit mass and is economical among storage methods for using hydrogen as fuel. As the demand for hydrogen increases, the need to develop a storage and supply system of liquid hydrogen is emphasizing. In order to liquefy hydrogen, it is necessary to pre-cool it to a maximum inversion temperature of -253℃. The Gifford-McMahon (GM) refrigerator is the most reliable and commercialized refrigerator among small-capacity cryogenic refrigerators, which can extract high-efficiency hydrogen through liquefied hydrogen production and boil of gas re-liquefaction. Therefore, in this study, the optimal conditions for liquefying gas hydrogen were sought using the GM cryocooler. The process was simulated by PRO/II under various cooling capacities of the GM refrigerator. In addition, the flow rate of hydrogen was calculated by comparing with specific refrigerator capacity depending on the pressure and flow rate of a refrigerant medium, helium. Simulations were performed to investigate the optimal values of the liquefaction flow rate and compression pressure, which aim for the peak refrigeration effect. Based on this, a liquefaction system can be selected in consideration of the cycle configuration and the performance of the refrigerator.

• 한국진공학회지
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• 제20권4호
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• pp.243-251
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• 2011

국내에서 개발 중인 맥동관형 냉동기 및 일반적인 GM 냉동기 성능평가를 위해 냉각용량 측정 장치를 제작한 후, 측정절차 검토 및 장치 성능확인의 일환으로 상용 냉동기의 냉각용량을 측정했다. 측정된 2차원 냉각용량 차트는 실험에 사용한 냉동기 모델이 가지는 고유 특성을 잘 나타냈다. 이 논문에서는 제작된 냉각용량 평가 장치의 설계사항 및 시운전 결과를 소개한다.

• 한국지열·수열에너지학회논문집
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• 제14권3호
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• pp.29-34
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• 2018

To present the design direction of the thermoelectric module (TEM) refrigerator, analysis of the effect of the design parameters on the energy efficiency and performance of the refrigerator is performed. The design parameters considered are the cooling capacity of the TEM and the heat transfer performance of the heating and cooling surface of the TEM. The heat transfer performance is the most effective design parameter for improving cooling power. The smaller ΔT and cooling capacity of the TEM make the higher efficiency of the refrigerator.

• 한국초전도ㆍ저온공학회논문지
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• 제24권4호
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• pp.71-77
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• 2022

Sub-Kelvin cooling has been generally demanded for the fields of low temperature physics, such as physical property measurements, astronomical detection, and quantum computing. The refrigeration system with a small size can be appropriately introduced when the measurement system does not require a high cooling capacity at sub-Kelvin temperature. The dilution refrigerator which is a common method to reach sub-Kelvin, however, must possess a large ³He circulation equipment at room temperature. As alternatives, a sorption refrigerator and a magnetic refrigerator can be adopted for sub-Kelvin cooling. This paper describes those coolers which have been developed by various research groups. Furthermore, a cold-cycle dilution refrigerator of which the size of the ³He circulation system is minimized, is also introduced. Subsequently, a new concept of dilution refrigerator is proposed by our group. The suggested cooler can achieve sub-Kelvin temperature with a small size since it does not require any recuperator and turbo-molecular vacuum pump. Its architecture allows the compact configuration to reach sub-Kelvin temperature by integrating the sorption pump and the magnetic refrigerators. Therefore, it may be suitably utilized in the low temperature experiments requiring low cooling capacity.

• 설비공학논문집
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• 제11권1호
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• pp.133-146
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• 1999

The charge operation of an ice storage system has been analyzed in this paper. The thermal characteristics of major components of the ice storage system. i.e., the refrigerator and the ice storage tank are evaluated from performance tests on an existing ice storage system. Based on the measured data for thermal characteristics, a simulation is carried out for the charge operation and the effect of the refrigerator size on the system performance is investigated. The results indicate that the larger the refrigerator size for a given storage capacity, the lower the inlet temperature of the ice storage tank so that the lower the efficiency of charge operation. It is also found that there exists an optimal size of the refrigerator with which the ice storage at the end of the charge operation is maximized, but the complete charge is not possible even with the optimally sized refrigerator. This leads to the result that the design capacity of the storage tank should be larger than the required amount of cold energy for the daytime cooling considering the practically chargeable amount of cold energy during the nighttime. Where the cooling load sharing of the storage is 40%, the nominal capacity of an ice storage tank needs to be larger than the required storage amount by 30%.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.292-297
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• 2008

Various types of refrigerators become popular in the market such as a common refrigerator, kimchi refrigerator and wine cellar. It is required to develop a multi function refrigerator which has different purposes in each evaporator. In this study, the performance of a multi type refrigerator system, which consists of one machine room and three evaporators, was measured in a bench type multi refrigerator. The multi type refrigerator system was tested by varying the number of refrigerator cabinet, refrigerant charge amount, temperature condition. Based on experimental data, the multi type refrigerator showed better performance than the conventional refrigerator(single type) At the same external load condition, the COP of the multi type refrigerator was $1.22{\sim}1.29$, but the COP of the single type refrigerator was 1.0.

• 설비공학논문집
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• 제14권10호
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• pp.817-824
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• 2002

A diffusion absorption refrigerator is a heat-generated refrigeration system. It uses a three-component working fluid consisting of the refrigerant (ammonia), the absorbent (water) and the auxiliary gas (typically hydrogen). This system has no moving parts and the associated noise and vibration. In this study, the operating characteristics of diffusion absorption refrigerator are investigated through cycle modeling and simulation. System parameters considered in this study are the charged concentration of ammonia aqueous solution, the concentration difference between absorber inlet and outlet and the system pressure determined by the amount of auxiliary gas charged. It was found that there exists a critical value of concentration difference that maximizes the refrigerating capacity. And the lower the system pressure, the higher the refrigerating capacity.

• 설비공학논문집
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• 제21권6호
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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.