한해를 보내며

윤상국,Yun, Sang-Guk 대한건축사협회 1995 建築士 Vol.1995 No.12

회원작품: 포천시립 소흘도서관

윤상국,Yoon, Sang-Guk 대한건축사협회 2010 建築士 Vol.2010 No.7

LNG 냉열 이용의 현황과 전망

윤상국,Yun, Sang-Guk 한국설비기술협회 1993 설비 : 공조ㆍ냉동ㆍ위생 Vol.10 No.4

유제품 수송용 공융냉동판 적용 냉동차량 시스템 연구

윤상국 한국마린엔지니어링학회 1999 한국마린엔지니어링학회지 Vol.23 No.3

The objective of this study is to developed the refrigeration vehicle system installed eutectic olu-tion plates which consists of copper tubes carrying the refrigerant between two aluminum plates and the space between the plates filled with eutectic solution. The numerical analysis for the loca-tion of plates to get the uniform low temperature distribution in storage space was carried out and the result showed that the top left-side and right-side walls were the proper places to install plates. For three different concentrations of ethylene glycol solution the temperature distribution of inside space were measured during the day time of summer and the 21% solution was found to be properto sustain the temperature of $5-10^{\circ}C$ for milk transportation. The result showed that the refrigeration truck installed eutectic plates was very efficient to keep the milk fresh during vehicle transportation.

LNG 냉열을 이용한 폐타이어 저온분쇄 연구 1

윤상국 한국폐기물자원순환학회 1995 한국폐기물자원순환학회지 Vol.12 No.2

LNG 냉열의 보유 엑서지 분석

윤상국 대한설비공학회 2015 설비저널 Vol.44 No.2

GAX 암모니아 흡수식 열폄프의 발생기 일체형 정류기의 열 및 물질전달 해석

윤상국 대한설비공학회 1999 설비공학 논문집 Vol.11 No.4

A generator-GAX combined rectification system of an ammonia absorption heat pump was investigated to get the optimum design values. The mass and heat transfer phenomena of the rectification system were analysed. The number of column plates, equilibrium temperature of solution on each plate and flow rates of solution and vapor generated were predicted. The characteristics of mass and heat transfer of the generator-GAX combined rectification system, i.e. concentration difference of leaving solution and vapor on each column plate, were found to be mainly governed by the pressure of generator, reflex ratio and temperature difference of analyser coolant. The number of rectification column plates for each different pressure in generator was obtained. The optimum locations for installing the feeder from solution-cooled absorber and GAX desorber in generator were predicted. The improvement of COP was followed by the increase of the rectifier efficiency and the number of column plate, and the decrease of reflex ratio.

고효율 증기 분리식 2단 팽창 냉동 사이클 성능 특성 연구

윤상국 대한설비공학회 2019 설비공학 논문집 Vol.31 No.3

The objective of this study was to improve the performance of the vapor compression refrigeration cycle comprised of a compressor, condenser, expansion device, and evaporator. In an original refrigeration system, a portion of the liquid refrigerant evaporates after the expansion process. The vaporized refrigerant does not have a role in the refrigeration effect in the evaporator. This study, therefore, aims to improve the energy efficiency by introducing a vapor separation mechanism in a two-stage expansion refrigeration cycle. In other words, the vapor separation process would separate the vapor from mixture beforehand so that higher amounts of liquid refrigerant flow within the evaporator. Results indicated a significant improvement of about 30% more than the existing refrigeration cycle using the new vapor-separated cycle, when a middle expansion pressure of 5 bars is applied in a typical R134a domestic freezer cycle with high pressure conditions of 10.166 barat 40℃ and low pressure conditions of 1.064 bar at -25℃. Moreover, since the mass flow-rate of the liquid phase in the evaporator decreased by about 15%~20% more than the current cycle, evaporator size could be significantly reduced. 본 연구에서는 종래 증기 압축식 냉동기를 개선한 증기 분리식 2단 팽창 냉동 사이클을 고안하여, 냉장고냉동 공간을 기준한 냉매 R134a를 적용한 시스템을 분석한 결과 다음과 같은 결론을 얻었다. (1) 증기 분리식 2단 팽창 냉동기는 중간팽창 압력 5 bar에서 성능계수가 종래의 증기 압축식 공정보다 30.5% 향상되었다. 이는 에너지를 크게 절약할 수 있는 새로운 고효율 냉동 사이클이 될 수 있음을 밝혔다. (2) 성능 향상은 중간 팽창 압력이 중간의 압력이 제일 크게 되며, 중간 압력을 기준하여 낮은 것보다 높게운전되는 것이 바람직함을 알 수 있다. (3) 증발기 온도 -5℃~-35℃ 범위에서 중간 압력 5 bar, -25℃를 기준하여 COP 대비하면 60.8%~-14%로 변화되나, 이 들 모두 종래 냉동기 공정보다 효율이 크게 높으며, 증발온도가 높은 냉동기에 본 공정이 적용될경우 50% 이상 획기적인 성능 향상을 이룰 수 있음을 알 수 있다. (4) 중간 팽창 5 bar의 경우 종래 공정보다 증발기 내부에 흐르는 냉매 질량유량흐름이 18.8%가 감소하게되어 증발기의 규격이 크게 감소하게 된다.

LNG냉열이용 BOG 재액화긍정 해석연구

윤상국,최형식 한국마린엔지니어링학회 2002 한국마린엔지니어링학회지 Vol.26 No.2

The Boil-Off-Gases(BOG) in the LNG production terminal are continuously generated during the unloading, storage and supply processes by the heat penetration. In order to use these gases as useful fuel, the reliquefaction process should be installed to put the reliquefied BOG in the main LNG supply line before the secondary pump in terminal. The current reliquefaction method of BOG in LNG terminal is the direct contact one between LNG and BOG in the absorption column. But the system has severe disadvantage, which is the 10 times of LNG circulation needed for unit mass of BOG reliquefaction. It causes, therefore, high power consumption of LNG circulation pump and excessive city-gas supply, even if short demand of NG is needed in the summer time. In this paper, the new reliquefaction system of BOG by using LNG cold energy with indirect contact in precooler was suggested and analysed. The result showed new indirect contact method of BOG reliquefaction system between LNG cold energy and BOG is much more effective than the current direct contact one because of only about 1.3 times of LNG circulation needed and higher energy saving by pump power reduction.

새로운 CO₂ 오토 캐스케이드 열펌프 시스템의 성능특성 연구

윤상국,Yun, Sang-Kook 한국마린엔지니어링학회 2017 한국마린엔지니어링학회지 Vol.41 No.3

20세기에 대두된 HCFC나 CFC계의 냉매들의 환경에의 악영향을 극복하기 위하여 보다 환경 친화적인 이산화탄소와 같은 자연냉매에 대한 관심이 커지고 있다. 겨울철 대기의 열원을 이용하여 증발을 유도하는 이산화탄소 열펌프는 증발기의 온도가 높아 효율이 상대적으로 낮아지고, 130bar가 넘는 고압으로 인하여 열펌프 설비 부품들의 제작의 어려움이 따르게 된다. 본 연구는 보다 낮은 압력의 새로운 2단 팽창식 $CO_2$ 오토 캐스케이드 열펌프를 고안하여 이러한 단점들을 해소하고 보다 효율을 증가시키고자 하였다. 새로운 오토 캐스케이드 열펌프에 2단 팽창방식과 효과적인 냉각방식의 시스템 구성을 하여 혼합냉매인 $CO_2$ 와 R32를 적용하였다. 공정에 고압 70bar, 중간 팽창압은 25bar, 최종 저압은 10bar를 적용하여 해석한 결과, 현재의 오토 캐스케이드 열펌프 공정의 COP는 1.629이었으나, 개선된 중간 압력 25bar의 2단 팽창 오토 캐스케이드 공정은 2.332로 현재의 공정보다 43.15% 향상되었다. 또한 저압측 증발기의 온도도 $-10^{\circ}C$ 이하가 되어 찬 외기에도 증발이 용이하게 발생되는 공정이 되었다. 본 공정이 향후 $CO_2$ 열펌프의 성능계수를 보다 향상시키고 고압에 따른 부품 문제들의 해소에 기여할 수 있는 공정으로 분석되었다. Owing to the harmful environmental effects of HCFC and CFC refrigerants discovered in the late 20th century, the need for environmentally friendly refrigerants such as $CO_2$ in cooling systems has increased. Air-source $CO_2$ heat pumps that utilize ambient heat in cold winter are less efficient because of a higher evaporation temperature, and it is difficult to manufacture the components of the heat pump owing to a super critical pressure of over 130 bar. This research aims to overcome these disadvantages and improve energy efficiency by introducing a new lower-pressure $CO_2$ auto-cascade heat pump system. $CO_2$-R32 zeotropic refrigerants were considered for two-stage expansion and effective cooling heat exchanging system configurations of the new auto-cascade heat pump. The results indicated that the efficiency of the two-stage expansion system was higher than that of the original one-stage expansion system. Furthermore, the two-stage expansion system showed significant performance improvements when the two-stage expansion stage from highest pressure of 70bar, intermediate expansion pressure of 25bar, and final low pressure of 10bar is applied. The COP of the new two-stage auto-cascade system (2.332) was 43.15% higher than that of the present simple auto-cascade system (1.629). Refrigerants having an evaporation temperature of $-10^{\circ}C$ or lower can be obtained that can be easily evaporated in an evaporator even at a low temperature.