• 기계저널
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• 제35권9호
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• pp.805-815
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• 1995

히트파이프에 관한 연구는 구미, 일본 등 선진 각국뿐만 아니라, 중국, 독립국가연합 및 동구권 에서도 다년간 활발하게 진행되어 왔다. 석유파동 이후 에너지 절약을 위한 노력의 결과로 폐 열회수 장치가 많이 개발되면서 히트파이프를 전열소자로 사용한 폐열회수 장치가 상당히 늘어나 이에 소요되는 히트파이프의 생산량도 급격한 신장세를 나타내고 있다. 이는 히트파이프 자체가 응답성이 좋고, 구조가 간단하며, 전열성이 뛰어난 장점으로 인하여 많은 연구가 이루어졌기 때 문이라 하겠다.그 응용분야는 인공위성으로부터 폐열회수용 열교환기, 전기장치 전자소자의 냉각, 음향기기의 냉각, 태양열과 지열의 유효이용, 플라스틱 금형의 냉각, 공작기계의 주축냉각, 포장 기계, 주방기기, 전력케이블의 냉각, 엔진 및 브레이크의 냉각 등 응용분야가 광범위하여 급격 하게 발전하고 있다. 그러나 국내에서는 히트파이프와 관련된 학술적인 연구결과가 발표되고 있을 뿐, 체계적이며 지속적인 연구가 수행되지 못하고 있다. 또한 산업계에서도 관련제품의 대 부분을 수입에 의존하고 있으며, 일부 제작업체에서는 제품이 나오고 있으나 축적기술결여로 그 성능면에 있어서 보증이 어려워 업계의 연구개발에 대한 노력이 절실히 요구되고 있다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.813-816
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• 2009

A commercial-scale RDF boiler that its burning capacity is 400 kg-RDF/hr and steam production capacity is 2 ton/hr. It has a chain type stoker and waste heat recovery system. Heat exchanger is vertical water-pipe so that soot blowing and removal is convenient during operation. Dry scrubber, bag filter and activated carbon tower have been installed for the reduction of air pollutant gases and dust. Analysing data of pollutants from stack such as $SO_x$. $NO_x$ and dioxin shows so good results that the boiler system could comply the regulated emission limits.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.218-224
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• 2006

Experimental results for pressure gradient of HCs refrigerants R-290. R-600a. R-1270 and HCFC refrigerant R-22 during condensing inside horizontal double pipe heat exchangers are presented. The test sections which have the tube inner diameter of 10.98mm. and the tube inner diameter of 8mm are used for this investigation. Hydrocarbon refrigerants have higher pressure drop than R-22 in both test sections with the diameters of 12.70mm and 9.52mm. Pressure drop increased with the increase of the mass flux. These results form the investigation can be used in the design of heat transfer exchanger using hydrocarbons as the refrigerant for the air-conditioning systems

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1127-1133
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• 2021

A Spent Fuel Pool (SFP) is designed to store spent fuel assemblies in the pool. And, a SFP cooling and cleanup system cools the SFP coolant through a heat exchanger which exchanges heat with component cooling water. If the cooling system fails or interfacing pipe (e.g., suction or discharge pipe) breaks, the cooling function may be lost, probably leading to fuel damage. In order to prevent such an incident, it is required to properly cool the spent fuel assemblies in the SFP by either recovering the cooling system or injecting water into the SFP. Probabilistic safety assessment (PSA) is a good tool to assess the SFP risk when an initiating event for the SFP occurs. Since PSA has been focused on reactor-side so far, it is required to study on the framework of PSA approach for SFP and identify the key factors in terms of fuel damage frequency (FDF) through a case study. In this study, therefore, a case study of SFP-PSA on the basis of design information of APR-1400 has been conducted quantitatively, and several sensitivity analyses have been conducted to understand the impact of the key factors on FDF.

• 한국지반공학회논문집
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• 제30권7호
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• pp.55-61
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• 2014

최근 들어 경제적이고 친환경적인 에너지 활용을 위하여 지열에너지 필요성이 증대되고 있다. 수평형 지중 열교환기는 설치 비용이 저렴하여 비용 대비 효율면에서 우수하다. 수평형 지중 열교환기의 타입에는 여러 가지가 있으나 이 중 슬링키형과 코일형이 우수한 것으로 알려져 있다. 따라서 본 논문에서는 $5m{\times}1m{\times}1m$ 크기의 모형 토조내에 수평 슬링키형과 코일형 지중 열교환기를 각각 설치한 후 열교환율을 실험적으로 측정하였다. 모형 토조 내에는 건조 상태의 주문진 모래가 조성되었으며 수평 슬링키형과 코일형의 피치 간격에 따라 열교환율을 측정하기 위해 30시간 동안 연속으로 열응답 시험을 실시하였다. 실험 결과 코일형 지중 열교환기 이용시 수평 슬링키형 보다 약 30, 40% 정도의 높은 파이프 단위 길이당 열교환율을 보였다. 또한 수평 슬링키형과 코일형 이용시 피치 간격이 넓을 때(피치/직경 = 1)가 좁을 때(피치/직경 = 0.2)보다 약 200, 250% 정도의 높은 파이프 단위 길이당 열교환율을 나타냈다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.728-734
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• 2004

Environmentally friendly refrigerants with zero ozone layer depletion potential are required to be used in refrigerators and air conditioners due to the difficulties related to ozone layer depletion and global warming. A rigorous study for the system performance with new refrigerants having zero ozone layer depletion potential is inevitable before adopting that as a new fluid. The HFC(Hydrofluorocarbon) potential has been recommended as alternatives. In this paper. system performance in the heat pump facilities were studied using R-290, R-600a. R-1270 as an environment friendly refrigerant. R-22 as a HCFC's refrigerant. The experimental apparatus has been set-up as a conventional vapor compression type heat Pump system. The test section is a horizontal double pipe heat exchanger. A tube diameter of 12.70mm with 1.315mm wall thickness is used for this investigation. The test results showed that the COP of hydrocarbon refrigerants were superior to that of R-22 and the maximum increasing rate of COP was found in R-1270. The refrigeration capacity of hydrocarbon refrigerants were higher than that of R-22. The compressor work was obtained with the maximum value in R-1270 and the minimum one in R-22.

• 센서학회지
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• 제12권2호
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• pp.95-101
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• 2003

보일러나 열교환기의 관 벽에 부착되는 스케일 방지용으로 설계된 초음파 발신기는 전기적 에너지를 초음파로 변환시켜주는 자왜소자와 발생된 초음파를 부하매질에 전달하는 도파봉으로 구성된다. 본 논문에서는 진동자로 사용되는 자왜소자의 형상설계와 진동자에서 발생된 초음파를 증폭시켜 부하매질로 전달하기 위한 몇 가지 형태의 도파봉에 대해 이론해석을 수행하여 필요한 사양을 도출하였다. 최종적인 도파봉의 길이는 음압 측정을 통해 선정하였다. 마지막으로 제작된 초음파발신기를 사용하여 보일러와 유사한 조건에서 스케일 방지효과를 확인하였다.

• International Journal of Air-Conditioning and Refrigeration
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• 제14권4호
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• pp.147-155
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• 2006

The drag reduction (DR) and heat transfer efficiency reduction (ER) of non-ionic surfactant were investigated as a function of fluid velocity, temperature, and surfactant concentration. An experimental apparatus consisting of two temperature controlled water storage tanks, pumps, test specimen pipe and the piping network, two flow meters, two pressure gauges, a heat exchanger, and data logging system was built. From the experimental results, it was concluded that existing alkyl ammonium surfactant (CTAC Cethyl Trimethyl Ammonium Chloride) had DR of $0.6{\sim}0.8$ at $1,000{\sim}2,000ppm$ concentration with fluid temperature ranging between $50{\sim}60^{\circ}C$. However, the DR was very low when the fluid temperature was $70{\sim}80^{\circ}C$. The new amine oxide and betaine surfactant(SAOB Stearyl Amine Oxide + Betaine) had lower DR at fluid temperatures ranging between $50{\sim}60^{\circ}C$ compared with CTAC. However, with fluid temperature ranging between $70{\sim}80^{\circ}C$ the DR was $0.6{\sim}0.8$ when the concentration level was $1,000{\sim}2,000ppm$.

• 한국유체기계학회 논문집
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• 제14권3호
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• pp.33-38
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• 2011

Medicated water electrolysis apparatus, which electrolyzes water into acidic water and alkaline water, was in the spotlight as becoming known the effect of alkaline water. It is known as good for health as removing active oxygen in the human's body and promoting digestion. But, the customers could not get that desired water temperature because these apparatuses are directly connected with a water pipe. So, the cooling system was developed for controlling the temperature of the alkaline water. One of the typical way is to store water in water tank and control the temperature. But, in this way, storing water can be polluted impurities coming from outside. For protecting this pollution, the cooling system based on indirect heat exchange method through phase change between water and ice was developed. In this study, we have calculated efficiency of the cooling system with phase change by experiment and commercial CFD(Computational Fluid Dynamics) code, ANSYS CFX. To consider the effect of latent heat that is generated by melting ice, we have simulated two phase numerical analyses used enthalpy method and found the temperature, velocity, and ice mass distribution for calculating the efficiency of cooling. From the results of numerical analysis, we have obtained the relationship between the cooling efficiency and each design factor.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.179-184
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• 2011

The development of new energy has attracted consideration attention due to the high oil price and environmental problems. In advanced country, they have tried to carry out a long range plan for energy. We need to develop new energy for Low Carbon Green Growth in Korea. The building is 30% among ratio of energy consumption in Korea. And in the past, heating energy was high ratio for energy using at home. But recently, the demand for cooling energy keeps growing due to rising average temperature on the earth and improvement of life quality. In this situation, the energy of lake water and ocean water has studied to utilize in advanced country because of low temperature at underwater. But the study for deep water is still a lot left to do. In this study, we analyzed district cooling system and the present condition. Analyzing the deep lake water cooling system in Toronto, we found an application of district cooling system using deep ocean water. Deep lake water uses heat source for district cooling and water source for city in Toronto. So reducing the initial cost, this city had economic effect. When DLWC was applied at existing building, the heat exchanger was installed instead of cooling tower and refrigerator. And the heat exchanger used to connect main pipe with cool water on city. System using deep ocean water can be applied as a similar way to supply cool water from lake to building.