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정영권(Young-Kwon Jung),이호생(Ho-Saeng Lee),김현주(Hyeon-Ju Kim),윤정인(Jung-In Yoon) 한국해양환경·에너지학회 2012 한국해양환경공학회 학술대회논문집 Vol.2012 No.5
Plate heat exchanger is being applied in the field of marine plants and chemical industry, such as OTEC and SWAC equipment. The study aims to interpret the thermal and pressure drop characteristics of plate heat exchangers to determine the geometric design parameters such as the channel space. In this study, heat transfer performance was numerically studies with respect to the flow pattern and channel space. The results from numerical analysis indicated that the j factor was linearly decreased with flow reate over every case. As the flow increases within channel spaces, the j factor was found to be decreased linearly. And the f factor is linearly decreasing with the increase of mass flow rate. The f factor was constant with flow rate over every case. As the flow increased within channel spaces, the f factor was found to be constant.
정영권(Young-Kwon Jung),김현주(Hyeon-Ju Kim),이호생(Ho-Saeng Lee),윤정인(Jung-In Yoon) 한국해양환경·에너지학회 2012 한국해양환경·에너지학회 학술대회논문집 Vol.2012 No.11
해수냉난방(Sea Water Air Conditioning) 시스템에서는 물을 해수와 판형 열교환기에서 열교환하여 고/저온의 물을 건물에 보내어 냉난방하는 방식을 채택하고 있다. 기존 판형 열교환기에는 비싼 티타늄 소재를 이용하지만, 이는 설비 구축 단계 및 유지 보수 단계까지 비용이 증가되는 약점을 지니고 있다. 따라서 기존의 티타늄이나 스테인리스보다 높은 열적 성능을 가진 소재를 판형열교환기에 적용하면 비용뿐 아니라 에너지를 효율적으로 이용할 수 있다. 본 연구에서는 판형 열교환기의 기존 소재(티타늄, 스테인리스 등)를 대체할 수 있는 코팅(DLC, 테프론 코팅)된 판형 열교환기를 제작하여, 유량에 따른 열전달 성능을 무차원수인 j factor로 분석하였다. Plate heat exchangers are currently used not in the chemical industry, but also in marine plants such as OTEC (Ocean Thermal Energy Conversion) and SWAC (Sea Water Air Conditioning). The plate heat exchangers, which are to exchange heat between hot(water) and cold side(seawater), have been widely adopted in many industrial application. Plate Heat Exchanger uses the expensive titanium. however, it has a weakness that equipment costs and maintenance costs increased. It was carried out in order to investigate the heat transfer performance for PHE. Heat transfer was investigated with the characteristic parameters, j factor.
정영권(Young-Kwon Jung),김현주(Hyeon-Ju Kim),이호생(Ho-Saeng Lee),윤정인(Jung-In Yoon) 한국해양환경·에너지학회 2014 한국해양환경·에너지학회 학술대회논문집 Vol.2014 No.5
이 논문은 물과 물의 열전달에서 다양한 핀 형상에 대하여 열전달과 압력강하 특성을 수치해석 기법을 이용하여 분석하였다. 플레이트 핀 열교환기는 핀 형태, 피치 등에 크게 영향을 받는다. 본 연구에서는 핀 설계 조건인 핀 형태, 핀 피치 그리고 핀 높이 등을 변화시켜 수치해석을 수행하였다. 일정한 유량에서 총괄열전달계수와 압력강하를 구하였다. 본 연구에서는 열교환 능력에 큰 영향을 미치는 핀 설계 인자를 도출하고 최적 조건의 핀 설계 조건을 제시하였다. In this paper, heat transfer and pressure drop characteristics of plate fin heat exchanger with different fin geometry are investigated. Tested fin geometry are fin type, fin pitch and fin height. Pressure drop and overall heat transfer coefficient are calculated as a constant heat flux is given to the heat exchanger unit.
정영권(Young-Kwon Jung),이호생(Ho-Saeng Lee),김현주(Hyeon-Ju Kim),윤정인(Jung-In Yoon) 대한조선학회 2012 대한조선학회 학술대회자료집 Vol.2012 No.5
Plate heat exchanger is being applied in the field of marine plants and chemical industry, such as OTEC and SWAC equipment. The study aims to interpret the thermal and pressure drop characteristics of plate heat exchangers to determine the geometric design parameters such as the channel space. In this study, heat transfer performance was numerically studied with respect to the flow pattern and channel space. The results from numerical analysis indicated that the j factor was linearly decreased with flow rate over every case. As the flow increased within channel spaces, the j factor was found to be decreased linearly. And the f factor is linearly decreasing with the increase of mass flow rate. The f factor was constant with flow rate over every case. As the flow increased within channel spaces, the f factor was found to be constant.
정영권(Jung Young Kwon),김재정,김영수(Kim Young Soo),김인관(Kim In Kwan) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
To improve the temperature efficiency, a newly designed Energy Recovery Ventilator(ERV) with conductive guide vane is experimented and verified. The experimented pilot system is designed base on various CFD analyses.(flow, heat transfer) The developed pilot system, 250 CMH capacity, reveal temperature efficiency improvement of 6.14% in cooling period and 8.07% in heating period compared to the conventional ERV. These improved efficiencies mean 'supply air' temperature is lower 0.49℃ in cooling period and higher 1.21℃ in heating period than ERV without conductive guide vane.
정영권 ( Young Kwon Jung ),우병우 ( Byung Woo Woo ),이동원 ( Dong Won Lee ) 대한천식알레르기학회 2018 Allergy Asthma & Respiratory Disease Vol.6 No.6
Purpose: Vitamin D plays an important role in calcium homeostasis and bone metabolism. It is associated with various diseases such as cardiovascular, immune, allergic and infectious disease. The aim of this study was to investigate the difference in clinical manifestations according to the concentration of vitamin D in mild bronchiolitis. Methods: We performed a retrospective review of medical records of patients with mild bronchiolitis from November 2016 to April 2017 in Daegu Fatima Hospital. Mild bronchiolitis was classified by the modified Tal’s score method. Patients were divided into 2 groups according to a 25-hydroxyvitamin D level of 20 ng/mL. We analyzed the clinical characteristics and laboratory data from the 2 groups. Results: Of the 64 patients, 19 were included in the deficiency group and 45 in the normal group. Vitamin D levels were 11.7±4.9 ng/mL in the deficiency group and 28.8±5.0 ng/mL in the normal group. There were no differences in clinical features between both groups. However, the vitamin D deficiency group had significantly longer hospitalization than the normal group (6.78±2.74 days vs. 5.3±1.7 days, P=0.045). In the deficiency group, the incidence of previous respiratory diseases was significantly higher (P=0.001). No significant difference in blood and respiratory virus tests was observed. Conclusion: Low vitamin D levels in mild bronchiolitis were associated with longer hospitalization and prior respiratory disease. Vitamin D may affect the course of mild bronchiolitis. (Allergy Asthma Respir Dis 2018;6:284-289)
R32, R22에 따른 판형 열교환기의 전열 특성에 대한 실험적 연구
정영권(Young-Kwon Jung),김현주(Hyeon-Ju Kim),이호생(Ho-Saeng Lee),윤정인(Jung-In Yoon) 한국해양환경·에너지학회 2014 한국해양환경공학회 학술대회논문집 Vol.2014 No.5
해양온도차발전에 사용되는 판형 열교환기의 재질은 해수의 특성상 고가의 티타늄을 많이 사용하고 있어, 제작비용의 상승의 주요 원인이 되고 있다. 이에 티타늄을 대체할 소재 및 코팅에 대한 연구도 진행중에 있다. 이에 본 논문에서는 여러 재질의 판형 열교환기에 대해서 냉매별로 열전달 및 압력강하 특성을 파악하고자 하였다. 실험에 사용된 열교환기의 재질은 티타늄, 스테인리스 등이며, 냉매는 R22와 R32를 사용하였다. 실험결과의 분석은 수정된 wilson plat 방법을 이용하여 분석하였다. 그 결과 냉매에 따른 응축/증발 열전달계수는 새로운 코팅방식이 적용된 판형 열교환기가 기존의 티타늄보다 높게 나타났다. In this study, we investigated the heat transfer and pressure drop characteristics of a plate heat exchanger in ocean thermal energy conversion (OTEC) system. We used deep seawater, surface seawater, and refrigerants (R22 and, R32) as heat and cooling sources. Our experiment was performed under the same conditions as those of and actual OTEC system : condensation temperatures of 8~20°C and 5~17°C for the deep seawater and refrigerant, respectively, and evaporation temperatures of 10~40°C and 13~45°C for the surface seawater and refrigerant, respectively. The experiments were performed in several operation modes of condensation and evaporation. The mass flow rates of the deep seawater, surface seawater, and refrigerant were varied over the rage of 60~90% of the total mass flow rate. The plates were made of titanium, stainless steel, nitride-coated New, Teflon-coated stainless steel, and DLC-coated stainless steel. The local and average heat transfer coefficients and pressure drops during condensation and evaporation were reported for R22 and R32 in the plate heat exchanger.
반용접식 판형 열교환기내 R22, R32 및 R32+R152a의 전열특성에 관한 연구
정영권(Young-Kwon Jung),김현주(Hyeon-Ju Kim),이호생(Ho-Saeng Lee),윤정인(Jung-In Yoon) 한국해양환경·에너지학회 2014 한국해양환경공학회 학술대회논문집 Vol.2014 No.11
해양온도차발전에 사용되는 판형 열교환기의 재질은 해수의 특성에 적합한 고가의 티타늄을 많이 사용하고 있어, 비용의 상승의 주요 원인이다. 티타늄을 대체할 소재 및 코팅에 대한 연구도 진행중에 있다. 이에 본 논문에서는 여러 재질의 판형 열교환기에 대해서 냉매별로 열전달 특성을 파악하고자 하였다. 실험에 사용된 열교환기의 재질은 티타늄, 스테인리스 등이며, 냉매는 R22를 기본으로 하였으며 R22를 대체하기 위한 냉매로 R32와 혼합냉매 R32+R152a를 사용하였다. 실험결과의 분석은 수정된 wilson plat 방법을 이용하여 열전달 특성을 분석하였다. 그 결과 모든 냉매에 대해서 응축/증발 열전달계수는 새로운 코팅방식이 적용된 판형열교환기가 기존의 티타늄보다 높게 나타났다. In this study, we investigated the heat transfer characteristics of a plate heat exchanger in ocean thermal energy conversion (OTEC) system. We used deep seawater, surface seawater, and refrigerants (R22, R32 and R32+R152a) as heat and cooling sources. Our experiment was performed under the same conditions as those of and actual OTEC system : condensation temperatures of 8~20°C and 5~17°C for the deep seawater and refrigerant, respectively, and evaporation temperatures of 10~40°C and 13~45°C for the surface seawater and refrigerant, respectively. The experiments were performed in several operation modes of condensation and evaporation. The mass flow rates of the deep seawater, surface seawater, and refrigerant were varied over the rage of 60~90% of the total mass flow rate. The plates were made of titanium, stainless steel, nitride-coated New, Teflon-coated stainless steel, and DLC-coated stainless steel. The local and average heat transfer coefficients during condensation and evaporation were reported for R22, R32 and R32+R152a in the plate heat exchanger.