• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.1-6
• /
• 2003

The purpose of the present study is to investigate the capillary heat transportation limitation in heat pipe according to the change of screen mesh wick porosity. Diameter of pipe was 6 mm, and mesh numbers are 100, 150, 200 and 250 and water was selected as a working fluid. According to the change of wick porosity and mesh number, the capillary pressure, pumping pressure, liquid friction coefficient in wick, vapor friction coefficient, and capillary heat transportation limitation are analyzed by theoretical design method of a heat pipe. As some results, the capillary heat transportation limitation in screen mesh wick heat pipe is largely affected by wick porosity and mesh number.

• 한국수소및신에너지학회논문집
• /
• 제10권1호
• /
• pp.41-48
• /
• 1999

산업단지에서 손실되는 막대한 폐열을 효율적으로 회수하고 이를 인근의 배후 도시에서 활용하기 위해서는 이에 적합한 열수송기술이 필요하다. 현재 온수나 증기에 의한 열수송은 배관을 통하여 열손실 및 마찰손실 등이 발생하므로 수송거리는 3 내지 5km가 한계이다. 그러나 대부분의 공단이 도시지역에서 10km 이상 떨어져 있으므로 이들 지역에서 발생되는 폐열을 적절히 활용하기 위해서는 새로운 열수송시스템이 개발되어야 한다. 본 연구에서는 수소저장합금이 수소를 흡수 또는 방출하면서 발열반응과 흡열반응을 일으키는 특성을 이용하여 산업공단지역의 폐열로부터 수소저장합금의 수소를 방출시키고, 이 수소를 인근 도시지역에 파이프라인으로 수송한 후 필요시 또 다른 수소저장합금과 반응시켜 열을 얻을 수 있는 열수송시스템에 대하여 고찰하였다. 이 시스템에서는 난방의 목적 외에도 수소의 흡수 방출온도가 낮은 합금을 이용하여 냉열을 얻을 수도 있으며, 폐열의 저장수단으로, 또한 수소를 수송함으로서 열수송의 수단으로 활용할 수 있다. 이에 따라 수소저장합금을 이용한 열수송기술의 문제점과 열수송시스템의 구성기술에 대하여도 검토하였다.

• 전기학회논문지
• /
• 제64권1호
• /
• pp.171-175
• /
• 2015

In this paper, because of global environmental problems such as energy shortage and abnormal climate, green energy development and energy saving technology development is being magnified. Heat insulation, the most basic and traditional energy saving method, is highly expected. Especially, simple and advanced heat insulation technique based on Nano material is promising future technology. The railway system also requires heat insulation. Especially, traditional heat insulator such as glass wool has been adopted frequently to rolling stock. The heat insulator is also adopted in general railway service buildings. Take account of cost-effective heat blocking performance, the heat insulator shall be adopted in diverse fields such as electric power, railroad, signal and communication. The only and direct solution for this problem is installing heat insulator with outstanding endurance, corrosion resistance and heat resistance to block outer heat Upgrading heat specification of equipment can be a solution, but since price and maintenance cost rise severely, this plan might be incongruous. In this research, energy saving effect of ultrathin heat insulator film was demonstrated by installing the film on roof of electrical room.

• 융복합기술연구소 논문집
• /
• 제4권1호
• /
• pp.5-8
• /
• 2014

Recently ionic liquids received much attention as novel materials capable of replacing traditional solvents. The applicability of the ionic liquids should be determined based on their physico-chemical properties. Heat capacity is one of the most important properties to be considered when a process is developed using the ionic liquids and currently DSC has been proved as an effective technique to measure the heat capacity. Micro DSCII can measure heat capacities of various liquids by both an isothermal step method and a scanning method. DSC Q100 and MDSC are able to measure heat capacities of several ionic liquids. For each ionic liquid linear regression of the heat capacity as a function of temperature has been performed to increase accuracy. To investigate the feasibility of ionic liquids as PCMs, their heat capacities have been measured by using Pysis I DSC. This paper briefly summarizes the present techniques of measuring heat capacities of ionic liquids by DSC.

• 설비공학논문집
• /
• 제10권3호
• /
• pp.334-342
• /
• 1998

In this experimental study, methanol was chosen as a system material for a long -distance heat transportation. Not only transition metals but also noble metals were investigated as an active component, and several metal oxides, such as ${\gamma}$-$Al_2$,$O_3$, $SiO_2$, etc. as a support. In general, transition metal catalysts absorbed more heat than noble metal catalysts. The amount of heat absorption and CO selectivity depends on temperature and methanol partial pressure, and 25$0^{\circ}C$ Ni/$SiO_2$ catalyst showed the best result for methanol decomposition reaction.

• 융복합기술연구소 논문집
• /
• 제2권2호
• /
• pp.59-65
• /
• 2012

This paper presents the study on applications of a surplus heat source. The heat is generated while hardwood charcoals are produced. We measure the temperature of the generated heat and analyze whether it can heat water or not. The analytic results show that the generated heat is useful as one of heat sources. In agricultural methods using a vinyl house, heating expenses will be saved by 10~20% when the surplus heat source is used.

• 융복합기술연구소 논문집
• /
• 제7권1호
• /
• pp.1-6
• /
• 2017

The Heat exchanger for deep geothermal system is very important to enhance the efficiency of the system. The co-axial heat exchanger is used due to the limitation of digging space. The heat transfer on the external surface of outer pipe should be high to receive a large amount of heat from the ground. However, the inner pipe should be insulated to reduce the heat loss and increase the temperature of discharge water. This study made experiment apparatus to describe the co-axial heat exchanger and measure the heat transfer coefficients on the internal and external surface. And the pin-fin was designed and fixed on the internal surface to increase the efficiency of heat exchanger. Finally, we calculated the temperature of discharge water using the heat transfer circuit of co-axial heat exchanger and heat transfer coefficient which from experimental results. The water temperature was reached the ground temperature at -500 m and following the ground temperature. When the water return to the ground surface, the water temperature was decreased due to heat loss. As the pin-fin case, the heat transfer coefficient on the internal surface was decreased by 30% and it mean that the pin-fin help to insulate the inner pipe. However, the discharge water temperature did not change although pin-fin fixed on the inner pipe.

• 태양에너지
• /
• 제18권3호
• /
• pp.169-175
• /
• 1998

수소저장합금이 수소를 흡수 또는 방출하면서 발열반응과 흡열반응을 일으키는 특성을 이용하여 산업공단지역의 폐열로부터 수소저장합금의 수소를 방출시키고, 이 수소를 인근 도시지역에 파이프라인으로 수송한 후 필요시 또 다른 수소저장합금과 반응시켜 열을 얻을 수 있는 열저장 및 이용시스템에 대하여 고찰하였다. 이 시스템에서는 반응온도가 낮은 합금을 이용하여 냉열을 얻을 수도 있으며, 폐열의 저장수단으로, 또한 수소를 수송함으로서 열수송의 수단으로 활용할 수 있게 된다. 폐열 대신에 태양열을 이용할 경우의 태양열의 저장수단으로 수소저장합금을 이용할 수 있다.

• 한국수소및신에너지학회논문집
• /
• 제11권1호
• /
• pp.43-49
• /
• 2000

현재 증기나 온수에 의한 열수송은 배관을 통하여 열손실 및 마찰손실 등이 발생하므로 수송거리는 3 내지 5km가 한계이다. 그러나 대부분의 공단이 도시지역에서 10km 이상 떨어져 있으므로 이들 지역에서 발생되는 폐열을 적절히 활용하기 위해서는 새로운 열수송 시스템이 개발되어야 한다. 수소저장합금은 수소를 흡수 또는 방출하면서 발열반응과 흡열반응을 일으키는 특성을 가지고 있으므로 산업공단지역의 폐열로부터 수소저장합금의 수소를 방출시키고, 이 수소를 인근 도시지역에 파이프라인으로 수송한 후 필요시 또 다른 수소저장합금과 반응시켜 열을 얻을 수 있다. 이 시스템에서는 난방의 목적 외에도 수소의 흡수 방출온도가 낮은 합금을 이용하여 냉열을 얻을 수도 있다. 따라서 수소저장합금은 폐열의 저장이나 열수송의 수단으로 활용할 수 있다. $MmNi_{4.5}Al_{0.5}Zr_{0.003}$, $LaNi_5$, $Zr_{0.9}Ti_{0.1}Cr_{0.6}Fe_{1.4}$, $MmNi_{4.7}Al_{0.1}Fe_{0.1}V_{0.1}$ 합금들이 열수송에 적합한 합금으로 선정되어 그 특성을 검토하였으며, 열수송시스템의 설계 및 제어기술에 대하여 검토하였다.

• 융복합기술연구소 논문집
• /
• 제4권2호
• /
• pp.51-54
• /
• 2014

Energy storage not only reduces the mismatch between supply and demand but also improves the performance and reliability of energy systems. The different forms of energy that can be stored, including mechanical, electrical and thermal energy. Phase change materials (PCM) are latent heat storage materials. A large number of phase change materials (organic, inorganic and eutectic) are available in any required temperature range. We concentrated on eutectic materials and made a eutectic by mixing urea and choline chloride. Heat capacity ($C_p$) is one of the most important properties to be considered when a process is developed using the eutectic and currently DSC (Differential Scanning Calorimetry) has been proved as an effective technique to measure the heat capacity. This study focused on measuring heat capacity ($C_p$) of the mixing urea and choline chloride by DSC.