• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.23 no.4
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• pp.306-313
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• 1994

• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.76-80
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• 1997

Acoustic resonance characteristics were analyzed and their effect on the refrigerating capability were experimentally verified on a fabricated Hofler-type thermoacoustic refrigerating system. Factors governing the overall resonance are the resonator composed of a cavity and two pipes, the loudspeaker driving the resonator, and rear side impedance characteristics of speaker housing. All these are coupled with electric constants of the speaker to exhibit electric resonance. Also the 'wall-effect' within the resonator causes attenuation to reduce the sharpness of the resonance. Analysis and experiments showed housing and the wall-effect of the resonator reduce the sharpness of resonance. Maintaining the accuracy of the resonance is, therefore, very important for efficient refrigeration.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.15-20
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• 2000

High pressure, pressure ratio, refrigerating effect, heat transfer from the condenser and the power of the compressor etc. of a self-made refrigeration equipment for R-12 are investigated when R-12 and R-134a are used as the coolants. The comparison between the performance for R-12 and that for R-134a is made. As a result, R-134a is better than R-12 in the view of high pressure, refrigerating effect and the coefficient of performance and vice versa in the view of pressure ratio, exit gas temperature from the compressor and heat transfer from the condenser.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.12
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• pp.32-38
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• 2004

초고층건물의 건설이 증가되고 있지만 건물외파와 출입문의 기밀도가 낮게 유지될 때, 이러한 누설면적과 층별로 구획할 수없는 수직샤프트(계단실 등)와 직렬로 배치될 경우, 필연적으로 발생하게 되는 굴뚝 현상(stack effect)의 발생원인과 차압크기 산정하는 방법 및 예방대책을 소개하고자 한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.564-571
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• 2001

The present study investigated the effect of key parameters on the performance of a cascade system using R-22 and R-23 refrigerants. Experimental data for the cascade system have been compared with simulation results using thermodynamic analysis. The cascade system tested at the evaporating temperature of $-80^{\circ}C $ and the condensing temperature of$40^{\circ}C $. The key experimental parameters were the evaporating temperature of the HTC(-35, -30, -25, -20, $-15^{\circ}C $) and mass flux of the HTC(200, 250, 300kg/$m^2$s). As the evaporating temperature and the mass flux of the HTC were increased respectively, the COP and the refrigerating efficiency were increased and then decreased while the volume flow rate per unit refrigeration capacity showed the opposite trend. The maximum COP and refrigerating efficiency were obtained at the evaporating temperature of the HTC of $-25^{\circ}C $ and the mass flux of 250 kg/$m^2$s.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.3
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• pp.43-49
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• 2004

This article reviews R＆D of triple effect cycle developed in Japan. Most of the refrigeration and heat pump technologies are dominated by vapor compressor system. The vapor compressor system, however, is highly concerned with the environmental regulations , as most of the vapor compressor technologies are using CFCs or HCFCs which are known as ozone depleting and global warming gases. As a consequence, refrigeration technologists are trying to invent or to develop an alternative to vapor compressor refrigeration devices. Thermally driven, absorption technology is one of the possible alternatives. At the moment, absorption cycle is most promising technology The paper summarizes briefly the current research and development in advanced technologies of triple effect absorption chiller-heater in Japan.(omitted)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.3
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• pp.7-10
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• 2004

삼중효용 흡수식 냉동기의 기본 원리, 사이를 구성 방법 및 특성, 제품 개발을 위한 핵심 기술에 대하여 알아본다. 현재 널리 사용되는 흡수식 냉동기는 대부분이 이중효용(double effect) 기기이며 그 동안의 많은 기술 축척과 연구개발의 결과, 성능이 향상되어 최근 일본에서 출시되는 신제품은 냉방 COP가 약 1.3을 넘어서고 있다. 그러나 이중효용 흡수식 냉동기로서는 도달 가능한 COP에 한계가 있기 때문에 2-3년 전부터 삼중효용 흡수식 냉동기에 대한 연구가 일본 등에서 활발히 진행되고 있다.(중략)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.10 no.1
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• pp.12-21
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• 1981

The Enthalpy Model was verified in order to analyze two- dimensional phase change problems. By using the Enthalpy Model, interface locations, frozen fraction rates, heat flux distribution rut cooled surfaces, and surface-integrated heat flux were purely numerically calculated in rectangular thermal storage units, whose initial condition was saturated liquid and phase change material was cooled on its boundaries by convective heat transfer. The calculations were performed for various Stefan numbers and Biot numbers. The effect on those dimensionless numbers were explained.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.11
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• pp.63-68
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• 2003

주방환기의 계획에 있어서 조리시 발생하는 오염물질을 적절히 배기시키는 것이 가장 중요하다. 기구의 배치와 발열량을 평가하고 후드의 위치와 종류 그리고 덕트직경과 경로를 결정하며 적정한 풍량을 제거하기 위한 배기팬을 선정한다. 그러나 일반적인 실내 공기밸런스 계획을 시행함에도 불구하고 배기된 체적에 해당하는 풍량을 보충 공급하는 방식에 대한 고려는 현재 상대적으로 부족한 상태이다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.3
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• pp.295-304
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• 1987

The purpose of this study is to develop a computer model for simulating the water-lit hium bromide absorption heat transformer (AHT) Including all major components and to find the flexibility in operation. The effect of source hot water temperature, cooling water temperature, useful hot water flow rate, cooling water flow rate and evaporator circulation flow rate were investigated. The coefficient of performance (COP), temperature boost $({\Delta}T\;=\;T_A\;-\;Ti)$ and concentration variations can be predicted. The performance study indicates that the performance of AHT increases for the waste hot water temperature increasing and with a decrease of the cooling water temperature. The effect on performances of useful hot water flow rape is significant except on temperature boost. Also the effects on performance of cooling water flow rate and evaporator circulation flow rate are small. It is shown that the computer program is valuable to predict the performance of absorp-tion heat transformer units at various working corditions.