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제설⋅방빙용 친환경 Thermosyphon 열성능 연구
이석진,강석경,서진혁,이정호 한국유체기계학회 2024 한국유체기계학회 논문집 Vol.27 No.4
Snow melting and anti-icing on the roads are crucial during the winter season. Conventional methods such as de-icing agents and electric heatings exhibit great challenges to fire hazards, environmental pollution, and accelerated corrosion of roads and vehicles. The corresponding research has been conducted on applying geothermal thermosyphon utilizing geothermal energy as a heat source for snow melting and anti-icing on roads. However, working fluids such as ammonia, commonly used in geothermal thermosyphons, can potentially pose significant toxicity to human beings in the event of leakage or contribute to global warming. In response to these concerns, acetone can be chosen as an alternative working fluid, and a lab-scale geothermal thermosyphon was fabricated for experimental validation. Experimental heat flux data of the condenser were compared with the calculated values obtained using the equation for heat flux provided in the 2019 ASHRAE Handbook, which is required for snow melting and anti-icing. The experiments confirmed that the geothermal thermosyphon can effectively melt road snow and anti-icing using acetone as a working fluid. The experiments were conducted by varying the filling ratio of working fluids to compare the thermal performance of the geothermal thermosyphon. It was determined that acetone needs to be charged at a filling ratio of 75% or higher for optimal thermal performance of the geothermal thermosyphons.
김규일,서진혁,강석경,이정호 한국유체기계학회 2024 한국유체기계학회 논문집 Vol.27 No.1
With the rising energy demand, waste heat recovery applications become more important than ever. A thermosyphon heat exchanger is one of the most effective devices for recovering waste heat. Numerical methods can be applicable to design thermosyphon heat exchangers, but it takes huge computation time and cost. For these reasons, several studies tried to calculate the thermal performance of thermosyphon heat exchangers without numerical methods. However, these attempts did not consider phase-change phenomena in thermosyphon and pressure drop through heat exchangers. A design program using an empirical analysis model has been proposed to avoid a complex numerical simulation. The proposed thermal design program includes the thermal resistance model, empirical correlations of tube banks with external flow, and the ε-NTU method for heat exchangers. The overall heat transfer coefficient is obtained through the thermal resistance model to design the heat exchanger based on the ε-NTU method. Empirical correlations are used to obtain phase-change heat transfer coefficients, external convection heat transfer coefficients, and pressure drops of thermosyphon heat exchangers. A heat exchanger including 95 thermosyphons in a staggered array has been manufactured and tested in 9 different conditions to validate the thermal design program. Comparing the design program with the thermal performance test result shows an average error of 0.8% for thermal performance and a maximum error of 5.2% for pressure drop. This result shows that the thermosyphon heat exchanger design program presented in this study can be useful in the design process in its engineering applications.
나노유체를 이용한 써모사이폰의 열전달 성능 특성에 관한 실험적 연구
이무연(Moo Yeon Lee),조중원(Chung Won Cho),이호성(Ho Seong Lee),원종필(Jong Phil Won),임택규(Taek Kyu Lim) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.11
본 논문은 나노유체를 적용하여 써모사이폰 열전달 성능 특성 변화를 실험적으로 규명하는 것을 목적으로 하고 있다. 이를 위하여, 증발부 내부체적을 공유하는 3 개의 독립된 파이프를 가지는 써모사이폰을 제작하였으며 증류수, Ag 나노유체 그리고 TiO₂ 나노유체에 대하여 충진량, 증발부에 가해지는 입력열량 그리고 농도변화에 따른 써모사이폰 성능특성 변화를 고찰하였다. 증류수를 작동유체로 사용하는 경우 써모사이폰의 최적충진량은 30%로 결정되었고, TiO₂ 나노유체를 적용하는 써모사이폰 열저항이 Ag 나노유체를 적용한 경우에 비하여 평균 18.1% 감소하였다. 또한, 300W 입력열량 및 TiO₂ 나노유체 농도 1%에서 써모사이폰의 열전달 성능은 가장 우수하였다. This study aims to experimentally investigate the heat transfer characteristics of a thermosyphon using nanofluids. A thermosyphon with three individual pipes, which share the internal volume of the evaporator section, was designed, and its performance was tested for various charge amounts, input powers of the evaporator section’s heater, and concentrations of working fluids. The optimized charge amount of the thermosyphon using distilled water was 30%, and the thermal resistance of the thermosyphon with TiO₂ nanofluid was 18.1% lower than that with Ag nanofluid. In addition, the heat transfer performance of the thermosyphon with TiO₂-1% was optimized at an input power of 300 W at the evaporator section’s heater and a charge amount of 30%.
김봉환,윤병도,김경훈 경희대학교 산학협력기술연구원 2001 산학협력기술연구논문집 Vol.7 No.-
According to the improvement of PC performance, it is expected that calorific value, which causes PC to malfunction, is increased. Therefore, the development of new cooling system is recently required. As the method to solve this problem, we developed loop type heat pipe. The heat pipe, which is a sealed box attached wicks, has a high performance on heat transfer, using a huge laten heat which is a generated during a phase change. Thermosyphon is a simple sealed tube in which a little working fluid is filled as the state of a static liquid pool. The advantage of heat pipe and thermosyphon is like that these are a small size, light weight, simple shape and long life. In addition, these have a good performance on a heat response and a coefficient of heat transfer, a wide rane of applicable temperature and no a supply of power from the outside. On the other hand, these have defects like that these have a large flow resistance and thermal resistance, and a heat transfer is restrained by the working limit. In this study, it is confirmed that loop type heat pipe reduces a flow resistance and thermal resistance and has a good performance on a cooling effect.
다발형 써모사이폰을 적용한 APR1400 격납건물 피동냉각계통 개념설계
남경호(Gyeong-Ho Nam),박준석(Jun-Seok Park),김상녕(Sang-Nyung Kim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
As we can see in the case of the Fukushima nuclear power plant accident, the integrity of containment is directly related to the safety of a nuclear power plant. Because of this, various concepts, such as the Passive Containment Cooling System(PCCS), are in the process of research to ensure the integrity of the containment. In this study, the PCCS was designed in the form of a assembly where several Two-Phase Closed Thermosyphons(TPCT) comes together to form one adiabatic region by grafting TPCT, to minimize the number of penetrations on the top of the dome of the containment as well as to remove the decay heat. The main purpose of this study is to analyze the expected heat transfer phenomena and to confirm the interpretation of the resulting heat transfer coefficient when applying the TPCT assembly of Multi-Pod Heat Pipe(MPHP) to the APR1400.
부분 경사형 다채널 평판 써모사이폰의 열성능에 관한 실험적 연구(수평가열시 응축부 경사각 및 길이의 영향)
김민석(Min Seok Kim),권용하(Yong Ha Kwon),김종수(Jong Soo Kim) 대한설비공학회 2019 대한설비공학회 학술발표대회논문집 Vol.2019 No.-
본 연구에서는 수평가열시 다채널 평판형 써모사이폰의 응축부 경사각 및 길이가 써모사이폰의 열성능에 미치는 영향을 평가하였다. 실험에 사용된 다채널 평판형 써모사이폰은 채널 수 56개, 작동유체 Novec-7100, 충진율은 20, 40% vol., 입열량은 6, 14W 조건에서 응축부의 경사각과 길이를 조절하며 실험하였다. 실험결과, 입열량, 충진율이 작은 경우가 큰 경우에 비해 높은 열성능을 보였으며 경사각에 따른 유효열전도율 및 발열부 온도변화에 대한 경향성은 발견할 수 없었다. 응축부 길이가 긴 경우가 짧은 경우보다 유효 열전도율 값이 3~4배 정도 크고 수평가열 조건에서도 냉각대상인 발열부 온도가 작동온도 조건을 만족하였다.
김봉환 ( B. H. Kim ),김경훈 ( K. H. Kim ) 한국분무공학회 2002 한국액체미립화학회지 Vol.7 No.2
N/A According to the improvement of PC performance, it is expected that calorific value, which causes PC to malfunction, is increased. Therefore, the development of new cooling system is recently required. As the method to solve this problem, we applied loop heat pipe to PC cooling system. The advantage of the loop heat pipe is that it has a small size, light weight, simple shape, long life and it has a good performance on heat transfer, no-noise, wide range of applicable temperature and no supply of power from the outside. It is confirmed that loop heat pipe reduces thermal resistance and has a good performance on PC cooling.