• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.1
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• pp.61-74
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• 2011

Critical environmental elements for long term preservation of a paper are temperature, humidity, dust, light, contaminants in air, and mold. Especially, temperature and humidity need special care, because they can not only directly degrade paper but also affect the degradation of the other elements. Therefore methods to monitor variation of temperature and relative humidity were studied. One of the methods was to use preservation index for evaluating preservation environment. Since the evaluation for preservation environment of a stack room investigated firstly by D. K. Sebera, PI(preservation index) and TWPI(Time-Weighted Preservation Index) by IPI is made to evaluate relatively preservation environment in a stack room. T. Padfield developed method which could calculate easy PI and TWPI. In this study, the preservation environment of stack rooms for paper storage in NAK(National Archives Korea) was evaluated by PI and TWPI. PI and TWPI of stack rooms for paper storage in NAK maintained good condition but PI depended on season. Then the preservation environment of stack rooms for paper storage in NAK was required to maintain continuously PI and TWPI regardless of season change.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.206-209
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• 2004

Mechanical behavior of a fuel stack was studied using an orthotropic material model. The fuel stack is essentially composed of a bipolar plate (BP), a gasket, an end plate, a membrane electrolyte assembly (MEA), and a gas diffusion layer (GDL). Each component is fastened with a suitable pressure. It is important to maintain a suitable contact pressure distribution of BP, because it influences the power efficiency of the fuel cell stack. When it is exposed to high temperature, its behavior must be stable. Hence, we performed stress analysis at high temperature as well as at room temperature. At high temperature, the contact pressure distribution becomes poor. Many patents have shown that using an elastomer can overcome this phenomena. Its effect was also studied. By using an elastomer, we found a good contact pressure distribution at high temperature as well as at room temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.703-714
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• 2009

One of the biggest problems in smoke control systems for high-rise buildings is stack effect, but there are no recognized methods or measures to solve the problem of stack effect as yet. The stack effect can be overcome by forming the uprising current inside the stair hall properly, but there is a limit to the height in supplying into the stair hall the smoke control air volume to be supplied to a floor in case of escape from fire. The limit to the height can be extended by over-coming the stack effect by pressurizing the stair hall and the ancillary room simultaneously. It can also be anticipated that the stack effect can be overcome by connecting the air supply shaft to the stair hall at the top. As a result of computer simulations using a network type of tool, it is found that adequate performance can be achieved by pressurizing the stair hall only for a building of 190m or less, and up to 360m when pressurizing the stair hall and the ancillary room simultaneously. In all those cases, however, an overpressure venting damper is required which operates within a suitable range for venting the overpressure outside.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.183-191
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• 2013

International network standards for SOLAS ship are composed of instrument network that controls and monitors machine in real time, shipboard control network that controls and monitors system through computer by human and telecommunication network that connects ship and shore. This paper describes development of stack for instrument network protocol complied with NMEA 2000 that is IEC 61162-3 international standards for SOLAS ship and also that of engine room monitoring system using the developed stack. Developed engine room monitoring system is certified by NMEA according to standards that require to pass about 1,600 test procedures.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.99-106
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• 2011

This paper deals with engine room layout design optimization of fuel cell electric vehicle (FCEV), which has been proposed as a potential alternative to fossil fuel depletion. Investing the great R&D efforts, the global vehicle manufacturers, especially Honda motor corporate, have shown not prototype vehicle but commercial vehicle using fuel cell in the market recently. In this paper, we analyze cooling performance and flow characteristic in the engine room of newly FCEV, in addition we suggest the optimization process for engine room layout design optimization. The two radiators in the vehicle for fuel cell stack and electronic components cooling have been analyzed and their performance are obtained in terms of cooling performance ratio (CPR). The value of CPR should always be less than one and based on criteria, we have achieved the optimum cooling performance of radiators for stack and electronic components. Aerodynamic performance is evaluated in terms of drag coefficient, improved through underbody modification using air devices.

• Journal of Energy Engineering
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• v.11 no.3
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• pp.254-261
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• 2002

The fabrication method for the main components of the polymer electrolyte membrane fuel cell stack such as electrodes, membrane-electrode assemblies, and bipolar plates was established for the effective electrode area of 240 ㎠. A counter-flow type 100-cell stack was fabricated by using the above components and then a maximum power of 7.44 kW for H$_2$/O$_2$ and 5.56 kW for H$_2$/air could be obtained at 70$\^{C}$ and 1 atm. It was seen that the distribution of the OCV for unit cells in the stack was uniform but the voltage deviation increased as the load increased due to the IR drop and the electrode polarization. The stack was applied to the power source of the fuel cell/battery hybrid electric golf car. It produced about 1 kW at a room temperature operation during the test run, which occupied about 43% of the total power required by the 2.3 kW motor.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.1-4
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• 2008

Fuel cells have the potential of providing several times higher energy storage densities than those possible using current state-of-the-art lithium-ion batteries, but current energy density of fuel cell system is not better than that of lithium-ion batteries. To achieve the high energy density, volume and weight of fuel cell system need to be reduced by miniaturizing system components such as stack, fuel tank, and balance-of-plant. In this paper, the thin flexible PCB (Printed circuit board) is used as a current collector to reduce the stack volume. Two end plates are made from light weight aluminum alloy plate. The plate surface is wholly oxidized through the anodizing treatment for electrical insulation. The opening rate of cathode plate hole is optimized through unit cell performance measurement of various opening rates. The performances are measured at room temperature and ambient pressure condition without any repulsive air supply. The active area of MEA is 10.08 $cm^2$ and active area per a unit cell is 1.68 $cm^2$. The peak power density is about 210 mW/$cm^2$ and the air-breathing planar stack of 2 Wis achieved as a small volume of 18 cc.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.209-213
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• 2008

The effects on the performance of natural smoke exhaust ventilators installed in high-rise buildings were analyzed depending on the wind velocities and smoke temperatures using CONTAMW tool. The results showed that the smoke exhaust ventilators can maintain given performances in such conditions as low smoke temperatures and low wind velocities. However, high smoke temperatures and high wind velocities can prevent the smoke ventilators to exhaust smokes from the fire room. Significant changes in stack effects in high-rise buildings can also occur with the opening of smoke ventilators in the fire floor.

• Journal of Environmental Science International
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• v.27 no.6
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• pp.359-369
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• 2018

A model has been developed to predict natural ventilation in a single zone building with large openings. This study first presents pressure-based equations on natural ventilation, that include the combined effect of wind and thermal buoyancy. Moreover, the concept of neutral pressure level(NPL) is introduced to consider the two-way flow through a large opening. The total pressure differences across the opening and the NPL are calculated, and nonlinear equations are solved to find the zonal pressure to satisfy mass conservation. For this analysis, an iterative technique of successively approximating the zonal pressure is used. The results of applying this study model to several simple cases are as follows. When there is no wind and only the stack effect is caused, a one-way flow occurs in both the top and bottom openings in the case of two openings of equal-area, and a one-way flow occurs in the top opening; however, a two-way flow occurs in the bottom opening in the case of two openings of unequal-area. When there is a wind effect, regardless of whether the outside air temperature is lower or higher than the indoor air temperature, air flows into the room through the bottom opening and out of the room through the top opening. As the wind velocity increases, the wind effect appears to be more influential than the stack effect owing to the temperature difference.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.10a
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• pp.187-190
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• 2005

The purpose of this study was to investigate using behavior and spatial composition of activity room in skilled nursing facilities for the elderly and to provide basic information about its space planning. The design guidelines for activity room were as follows. First, the plan of activity room is based on the use of once to twice per week and for 30 minutes per use, and is mainly for the human knowledge and art programs. Second, all cases of the same and different floor of the individual room could be considered as its location. Third, the area is recommended at least more than 6 square meters per person including participating elderly, staff, furniture, equipments and restroom. Fourth, the furniture of activity room include the shelves, table for at least 8 persons with enough knee space, wheel, and stack chairs. Toilets and water closet should be arranged for the emergency, and the windows to the hall and curtain door need to be avoided for soundproofs and easy accessibility of wheelchair users.