http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
냉매 충전량에 따른 CO<sub>2</sub>용 수냉식 열펌프의 성능 특성에 관한 연구
손창효,유태근,장승일,오후규,Son, Chang-Hyo,Yu, Tae-Guen,Jang, Seong-Il,Oh, Hoo-Kyu 한국마린엔지니어링학회 2007 한국마린엔지니어링학회지 Vol.31 No.5
The performance characteristics of water-chilling heat pump using $CO_2$ with respect to variation of refrigerant charge amount was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter-flow-type heat exchangers with concentric dual tubes, which are made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2400 mm length. The experimental results summarize as the followings : As the refrigerant charge ratio of $CO_2$ heat pump system increases, the discharge pressure and compressor ratio increases, but mass flow rate of refrigerant decreases. Also the compressor work increases with the increase of refrigerant charge ratio. However, the heating and cooling capacity of $CO_2$ heat pump decreases as the refrigerant charge ratio increases. The maximum heating COP of $CO_2$ heat pump system presented at 0.25 refrigerant charge ratio. It is possible to confirm the optimum charge ratio of $CO_2$ heat pump system by the viewpoint of heating COP.
경남수(Nam-Soo Kyoung),유태근(Tae-Guen Yu),손창효(Chang-Hyo Son),오후규(Hoo-Kyu Oh) 한국마린엔지니어링학회 2005 한국마린엔지니어링학회 학술대회 논문집 Vol.2005 No.-
The paper presents the heat transfer characteristics during cooling process of carbon dioxide(CO₂) in a helically coiled tube. The main components of the apparatus consist of a receiver, a variable speed pump, a mass flowmeter, a pre-heater, a gas cooler(test section) and an isothermal tank. The test section with the inner diameter 4.55 [㎜] is a tube in tube type heat exchanger with refrigerant flowing in the inner tube and water flowing in the annulus. The main results were summarized as follows : The heat transfer coefficient increases with respect to the decrease of the gas cooler pressure in a supercritical region and the increase of the refrigerant mass flux. The pressure drop decreases in increases of the gas cooler pressure and increases with respect to increases the refrigerant mass flux.
전민주(Min-Ju Jeon),유태근(Tae-Guen Yu),손창효(Chang-Hyo Son),오후규(Hoo-Kyu Oh) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.11
The cooling heat transfer coefficient of CO₂ (R-744) in helically coiled tubes was investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and a gas cooler (test section). The test section consists of a helically coiled copper tube of 4.55 and 2.45 ㎜. The experiments were conducted at saturation temperature of 100 to 20℃, and mass flux of 200 to 600 ㎏/㎡s. The test results showed the variation of the heat transfer coefficient tended to decrease as cooling pressure of CO₂ increased. The heat transfer coefficient with respect to mass flux increased as mass flux increased. The experimental results were also compared with the existing correlations for the supercritical heat transfer coefficient, which generally under-predicted the measured data. However, the experimental data showed a relatively good agreement with the correlations of Pitla et al. except for the pseudo critical temperature.
Hoo-Kyu Oh(오후규),Tae-Guen Yu(유태근),Geon-Sang Roh(노건상),Hak-Keun Ku(구학근),Jiating Yan 한국마린엔지니어링학회 2007 한국마린엔지니어링학회 학술대회 논문집 Vol.2007 No.-
The heat transfer characteristics of supercritical CO₂ during gas cooling process are investigated experimentally. The test section is a helically coiled tube with I.D. of 4.55, O.D. of 6.35 and length of 10000 [㎜]. The helical coil diameter is 41.35 and 26.75 [㎜], respectively. The apparatus consist of a receiver, a variable-speed pump, a mass flow meter, a pre-heater, a gas cooler (test section) and an isothermal tank. The range of the refrigerant mass fluxes is from 200 to 800 [㎏/㎡s] and the pressure in the gas cooler varies from 7.5 to 10.0 [㎫]. The main experimental results are summarized as follows; as the gas cooling pressure decreases gradually, the heat transfer coefficient increases greatly. The mass flux has a positive effect on heat transfer like constant property condition. The heat transfer coefficient at coil diameter 26.75 [㎜] is larger than that of coil diameter 41.35 [㎜]. The data is compared with the existing correlations, which generally under-predict the measured data. However the experimental data show a relatively good agreement with correlations by Pitla et al. except for pseudo critical temperature.
이산화탄소용 열펌프시스템의 성능특성에 관한 실험적 연구
장승일(Seong-Il Jang),전민주(Min-Ju Jeon),유태근(Tae-Guen Yu),손창효(Chang-hyo Son),오후규(Hookyu-Oh) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
냉매 충전량과 이차유체의 입구조건은 CO₂용 열펌프시스템의 성능실험에서 중요한 제어변수이다. 따라서, 열펌프사이클의 적용과 난방성능 향상을 위해 제어변수의 특성을 조사하는 것이 필요하다. 본 논문에서, CO₂용 열펌프 사이클의 성능 실험은 여러 가지 냉매 충전량에서 이차유체 입구조건에 변화를 주어 수행 되었다. 실험결과, 난방COP는 냉매 충전량이 증가함에 따라 1158g의 냉매 충전량에서 최대가 되었다가 감소하는 경향이 나타나며, 이는 COP,가 최대가 되는 냉매충전량이 존재함을 나타낸다. 또한, 난방성능은 가스쿨러내 이차유체의 질량유량의 증가에 따라 증가하였다. 가스냉각기내 2차유체의 입구온도가 10℃에서 40℃로 증가하면, 난방용량, 압축일량, 토출압력은 각각 -8.57%, -35.78%, 32.78%로 변화했으며, 증발기 2차유체의 입구 온도가 감소하였을 때 난방 COP는 감소하는 경향을 보였다.
오후규(Hoo-Kyu Oh),전민주(Min-Ju Jeon),유태근(Tae-Guen Yu),장승일(Seung-Il Jang),손창효(Chang-Hyo Son) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
The heat transfer of CO₂ has a greater effect on nucleate boiling more than convective boiling. Mass flux of CO₂ does not effect nucleate boiling too much. In comparison with test results and existing correlations, it is necessary to develop reliable and accurate predictions determining the evaporative heat transfer coefficient of CO₂ in a horizontal tube.