• 기술표준
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• 통권19호
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• pp.41-45
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• 2003

• 대한설비공학회지:설비저널
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• 제28권5호
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• pp.347-358
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• 1999

암모니아는 독성, 가연성 및 동 재질의 부식성 등의 단점은 있지만 CFC계 냉매가 개발되기 전에는 우수한 열역학 및 열전달 특성 때문에 냉매로서 가장 많이 사용되어져 왔다. 미국에서는 약120년, 일본에서는 약 80년 전부터 암모니아가 냉동 사이클에 사용되었고, 따라서 축적된 관련 기술 수준도 놀고 경험도 많은 편이다. 지금도 미국에서는 상업용 냉동기의 80% 정도가 암모니아를 냉매로 사용하고 있다. 우리나라도 냉동창고 냉동용으로는 암모니아 시스템이 널리 사용되고 있다.

• 설비공학논문집
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• 제16권6호
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• pp.522-529
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• 2004

In this study, external condensation heat transfer coefficients (HTCs) of flammable refrigerants of propylene, propane, isobutane, butane, DME, and HFC32 were measured on a horizontal plain tube, 26 fpi low fin tube, and Turbo-C tube. All data were taken at the temperature of 39$^{\circ}C$ with a wall subcooling of 3∼8$^{\circ}C$. Test results showed a typical trend that condensation HTCs of flammable refrigerants decrease with increasing wall subcooling. HFC32 had the highest HTCs among the tested refrigerants showing 44% higher HTCs than those of HCFC22 while DME showed 28% higher HTCs than those of HCFC22. HTCs of propylene and butane were similar to those of HCFC22 while those of propane and isobutane were similar to those of HFC134a. Based upon the tested data, Nusselt's equation is modified to predict the plain tube data within a deviation of 3%. For 26 fpi low fin tube, Beatty and Katz equation predicted the data within a deviation of 7.3% for all flammable refrigerants tested. The heat transfer enhancement factors for the 26 fpi low fin and Turbo-C tubes were 4.6∼5.7 and 4.7∼6.9 respectively for the refrigerants tested indicating that the performance of Turbo-C tube is the best among the tubes tested.

• 설비공학논문집
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• 제19권10호
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• pp.726-734
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• 2007

In this study, lower flammability limits (LFLs) of three hydrocarbon refrigerants (R600a, R290, R1270) and two hydrofluorocarbon refrigerants (R152a, R32) and DME (RE170) are measured by the method proposed by ASTM E681-04 Standard. Flammability tests are carried out at three temperatures of $23^{\circ}C,\;60^{\circ}C\;and\;100^{\circ}C$ and relative humidity 50%. Test results show that the present data for isobutane and propane obtained at $23^{\circ}C$ are similar to those found in the literature, confirming indirectly the reliability of the present test method and facility. For propylene, R152a, and R32, LFLs found in the literature differ considerably. Especially, the deviation of LFL of propylene is more than 30% among the literature data. The present data for propylene, R152a, and R32 agree with either of the data sets available. As the temperature increases from $23^{\circ}C\;to\;100^{\circ}C$, LFLs of all refrigerants tested decrease. LFLs of most refrigerants tested in this study at $60^{\circ}C$ decrease by $0.1{\sim}0.3%$ as compared to those at $23^{\circ}C$. Also LFLs of most refrigerants tested in this study at $100^{\circ}C$ decrease by $0.1{\sim}0.3%$ as compared to those at $60^{\circ}C$.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2013년도 추계학술대회 초록집
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• pp.93-94
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• 2013

에어컨 실외기는 냉매와 함께 가연성 윤활유가 고압으로 충전되어 있어 연소하중이 높다. 대부분의 건축물에 설치되는 에어컨 실외기는 미관을 고려하여 건물 외벽에 종렬로 설치하기 때문에 에어컨 실외기 또는 주변에서 화재가 발생하면 이들 실외기를 따라 고층으로의 연소 확대의 위험성이 있다.

• 설비공학논문집
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• 제5권3호
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• pp.217-225
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• 1993

Nonflammable mixtures of flammable and nonflammable refrigerants are possible as substitute refrigerants for use in domestic heat pumps and refrigerators. Refrigerant leakage from such a system is of paramount concern since it is possible that the resulting mixture composition remaining in system will reside in the flammable range. This paper presents a simulation of a leakage process of refrigerant mixtures. Idealized cases of isothermal leakage process are considered in this study representing a slow leak. Simulation is performed for selected composition of binary and ternary refrigerant mixture; R-32/134a and R-32/125/134a. Mixture compositions with respect to percentage leak of original charge are presented. In isothermal leakage process, both vapor and liquid compositions of more volatile refrigerant decrease during vapor and liquid leak, but the total composition of this component decreases during vapor leak and increases during liquid leak. Vapor and liquid compositions are determined depending on the vapor-liquid equilibrium relation of the refrigerant mixture. The refrigerant mixture left in the system can go to a nonflammable direction relying on which component in the mixture is flammable.

• 설비공학논문집
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• 제18권3호
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• pp.247-253
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• 2006

In this work, pool boiling heat transfer coefficients (HTCs) of hydrocarbon refrigerants are measured from a horizontal smooth tube of 19.0 mm outside diameter. Tested pure refrigerants are Propylene, Propane, Isobutane, Butane and Dimethylether (DME). The pool temperature was maintained at saturation temperature of $7^{\circ}C$ and heat flux was varied from $10kW/m^2$ to $80kW/m^2$ with an interval of $10kW/m^2$. Wall temperatures were measured directly by thermocouple hole of 0.5 mm out-diameter, 152 mm long and inserting ungrounded sheathed thermocouples from the side of the tube. Tested results show that HTCs of Propane, Propylene are 2.5%, 10.4% higher than those of R22 while those of Butane and Isobutane are 55.2%, 44.3% lower than those of R22 respectively. For pure refrigerants, new correlation can be applied to all of CFCs, HCFCS, HFCs, as well as hydrocarbons was developed. The mean deviation was 4.6%.

• 한국가스학회지
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• 제20권1호
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• pp.62-67
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• 2016

가장 깨끗한 화석연료 가운데 하나인 천연가스는 장거리 수송 시 부피를 줄이기 위해 액화된다. 그 중 소형 해양 천연가스 액화 플랜트는 면적이 작기 때문에 안전문제가 크게 대두된다. 하지만, 기존에 쓰이는 DMR (Dual Mixed Refrigerants) 공정은 가연성 냉매를 사용함으로써 화재의 위험이 있으며, N2 Expander 공정은 안전하지만 압축 에너지 효율이 낮다는 문제점이 있다. 따라서 안전하면서도 압축 에너지 효율 또한 높은 공정의 개발이 지속적으로 요구되는 상황이다. 본 연구에서는 DMR 공정에 비가연성 냉매인 Hydrofluorocarbon을 사용하여 안전성을 높임으로써 기존 공정들에 대한 대안을 제시하였다. 그 결과, 화재위험이 있는 DMR 공정보다 34.8% 낮은 압축에너지 효율을 보였으나, Single N2 Expander 공정보다 42.6% 향상된 압축 에너지 효율을 나타내었다. 결론적으로 이 연구에서는 안전하면서도 높은 에너지 효율을 내는 소형 해양 천연가스 액화 플랜트 공정을 설계하였다.