• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.32-38
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• 2009

In this paper, cycle performance analysis for cooling capacity, compression work and COP of R744($CO_2$) transcritical vapor compression refrigeration system is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include superheating degree, outlet temperature of gas cooler and evaporating temperature in the R744 vapor compression cycle. The main results were summarized as follows : The cooling capacity of R744 increases with superheating degree, but decreases with the increasing evaporating temperature and outlet temperature of gas cooler. The compression work increases with superheating degree and cooling pressure of R744, but decreases with the increasing evaporating temperature. And, The COP increases with outlet temperature and evaporating temperature of R744 gas cooler, but decreases with the increasing superheating degree. Therefore, superheating degree, outlet temperature and evaporating temperature of R744 vapor compression refrigeration system have an effect on the cooling capacity, compression work and COP of this system. With a thorough grasp of these effect, it is necessary to design the compression refrigeration cycle using R744.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.1
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• pp.26-33
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• 2000

최신의 암모니아의 냉동시스템들은 효율이 더 높고 더 안전하게 제작될 수 있다. 또한, 현재의 표준인 고충전 펌프순환 시스템들을 펌프를 사용하지 않고 증발기에 냉매를 과공급하도록 설계된 저충전 시스템들로 대체함으로써 기존의 암모니아 시스템들을 성능과 안전성을 향상시킬 수 있다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.7
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• pp.27-33
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• 2003

본고는 수송용 냉동차량의 신기술동향에 관한 것으로, 냉동차량의 시스템 개량, 대체냉매용 냉동차량의 개발, 진공 단열기술, 신개념의 냉동수송 기술동향 등을 소개한 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.626-629
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• 2012

In this paper, Actual refrigeration system and the data were analyzed in order to provide basic design data of Refrigeration system using the characteristic curve of the refrigerant. On the basis of the characteristic curve of the refrigerant developed simulation program and data of refrigeration system equipment data consisting of compressor, condenser, Receiver content, expansion valve, evaporator, liquid separator, leading to changes in temperature and Moliere were analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1427-1433
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• 2012

In this paper, cycle performance analysis of cascade refrigeration system using alternative FREON refrigerants and natural refrigerants are presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooled and superheated degree, and condensing and evaporating temperature, temperature difference of cascade heat exchanger in cascade refrigeration system. The COP of cascade refrigeration system increases with the increasing subcooled degree, but there is no significant changes with the increasing superheated degree. The COP of cascade refrigeration system depends on evaporating and condensing temperatures of cascade heat exchanger. Therefore, subcooled degree, evaporating and condensing temperature of cascade heat exchanger using alternative FREON refrigerants and natural refrigerants have an effect on the COP of this system. In this paper, COP of cascade refrigeration system using (R23 / R290), (R23 / R600), (R23 / R600a), (R23 / R717), (R744 / R404A) are higher 20 ~ 36 % than (R23 / R22), using R23 for low temperature system and R22 for high temperature system.

• 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%.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.42-47
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• 2012

In this paper, alternative natural refrigerant R290(Propane), R600(Butane), R717(Ammonia), R1270(Propylene) for freon refrigerant R22 were used working fluids for 2-stage compression and 1-stage expansion refrigeration system. The operating parameters considered in this study included evaporation temperature, condensation temperature, subcooling degree, superheating degree, mass flow rate ratio of inter-cooler. The main results were summarized as follows : The COP of 2-stage compression and 1-stage expansion refrigeration system increases with the increasing subcooling degree and mass flow rate ration of inter-cooler, but decreases with the increasing evaporating temperature, condensing temperature and superheating degree. Therefore, subcooling degree, mass flow rate ratio of inter-cooler of 2-stage compression and 1-stage expansion refrigeration system using natural refrigerants have an effect on COP of this system. The COP of natural refrigerants was higher than the COP of freon R22 in this study, so points to be considered are the security, the attached facilities for natural refrigerants than COP.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.182-188
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• 2011

In this paper, analysis on the performance characteristics of R744-R404A cascade refrigeration system is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree, compressor efficiency, and condensing and evaporating temperature in R404A high- and R744 low-temperature cycle, respectively. The main results were summarized as follows : It was observed that the highest COP of the system is achieved by higher superheating degree in R744 cycle than that in R404A cycle. The COP of the system increased by giving the subcooling degree in both cycles. The COP of the cascade system is the highest value when the system is operated at an optimum evaporation temperature.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.40-45
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• 2011

The purpose of research is to understand the characteristics of refrigeration system having a liquid-vapor phase separator after expansion device and precooling heat exchanger. After expansion process of typical refrigerant of freezer, R134a, the cold vapor of the expanded refrigerant mixture is separated in the liquid-vapor separator and introduced in the precooling heat exchanger to enable the liquid refrigerant to be subcooled. The analysis results showed that the increasing rate of refrigeration capacity and COP can be 8.6% and 1.4%, each. The cause of these performance improvements is due to the difference of the slope of saturated vapor and saturated liquid lines in Mollier diagram of refrigerant.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.425-429
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• 2010

최근 들어 단순 보관의 기능만을 가지고 있던 기존의 냉동창고가 보관뿐만 아니라, 규격화된 유통시스템을 갖추어 전체 물류 공급망 관리의 효율성과 경쟁력을 갖추고자 한다. 이를 위해 라디오 주파수를 이용하여 움직이는 물체를 인식, 추적, 분류할 수 있는 기술인 RFID (Radio Frequency Identification)를 적용할 수 있다. 그러나 RFID 기술을 도입하기 위해서는 여러 시나리오를 통해 최적의 실행 방안을 도출해 내야하며, 이를 바탕으로 자동화 프로세스를 지원해 줄 수 있는 RFID 애플리케이션을 개발할 수 있다. 본 논문에서는 RFID 기술을 적용하여 최적화된 비즈니스 프로세스를 지원하는 냉동창고 관리 시스템을 개발하고자 한다. 이를 위해 냉동창고 업무 프로세스를 분석하고 RFID 기술 도입에 따른 의사 결정이 필요한 설계요소들을 식별한다. 식별된 설계요소들은 RFID 배치 시뮬레이터를 이용하여 RFID 데이터가 비즈니스 프로세스에 통합되는 과정에 대하여 그 효율성을 판단할 수 있게 한다.