• Journal of Biosystems Engineering
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• 제20권4호
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• pp.360-367
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• 1995

The effect of air vent holes, stacking methods of boxes and clearance between boxes on static pressure drop, were measured to design of pressure cooling system. Static pressure drops in air vent hole of carton box were measured for different hole opening ratio from 1% to 5%. Static pressure drop was expressed as a function of superficial velocity as second-degree polynomial. At given static pressure in plenum chamber, static pressure drop in boxes was shown as second-degree polynomial of the number of carton box in series stacking method, as first-degree polynomial in height and parallel stacking method. In pressure cooling of 24 boxes of Tsugaru apple, air flow rates through clearance between the boxes were shown 1.27 and 1.65 times than those of through the inside of boxes at the plenum pressure of 10mmAq and 20mmAq, respectively.

• 한국지열·수열에너지학회논문집
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• 제14권3호
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• pp.29-34
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• 2018

To present the design direction of the thermoelectric module (TEM) refrigerator, analysis of the effect of the design parameters on the energy efficiency and performance of the refrigerator is performed. The design parameters considered are the cooling capacity of the TEM and the heat transfer performance of the heating and cooling surface of the TEM. The heat transfer performance is the most effective design parameter for improving cooling power. The smaller ΔT and cooling capacity of the TEM make the higher efficiency of the refrigerator.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1518-1523
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• 2003

The objective of the present work is to investigate an effect on the solution crystallization temperature difference and the cooling capacity of the absorption chiller by a solution cooler in the absorber. The cooling capacity of the absorption chiller can be higher, with the enhanced performance of the solution heat exchangers. But, because the solution crystallization temperature difference becomes smaller at the absorber inlet, the heat capacity of the solution heat exchangers might be limited by the danger of crystallization, which can cause the serious damages. In this paper, the heat capacity ratio of the solution cooler is defined as the ratio of the heat capacity of the solution cooler to that of the absorber. If it becomes larger in the additional type solution cooler, the solution crystallization temperature difference is augmented and the cooling capacity is also increased.

• 열처리공학회지
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• 제18권2호
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• pp.112-118
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• 2005

Study was focused on the effect of the cooling rate on the embrittlement behavior of Zircaloy-4 cladding simulated Loss Of Coolant Accident (LOCA) environment. Claddings were oxidized at given temperature and given time followed by various water quenching in the range of $0.6^{\circ}C$ and $100^{\circ}C$ per second. Cladding failed after water quenching above the threshold oxidation. Threshold oxidation was decreased as the cooling rate increased, which is due to the matensite structure formed during fast cooling rate.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.203-205
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• 2004

Welding sometimes should be done inside-hull after launching. The opposite side is contacted sea-water In this case, it should be a concern that the cooling rate expected very rapid may deteriorate microstructures, and hence these microstructures are hardened, cracking happens, or toughness would be impaired. Therefore, a test program simulating the situation has been planned and welded using the ship class materials (AH32, EH36) with the related welding consumables (E71Tl-1, E81Tl-K2) and then carried out to investigate the effect of cooling rate on weldments quality. Based on the test results, it could be concluded that the welds of which the opposite side of arc is exposed to wet or flowing water are not affected by rapid cooling.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.162-167
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• 2000

Construction machinery includes an engine enclosure separated from a cooling system enclosure by a wall to reduce noise and advance cooling system performance. For this structure, however, the axial fan cannot be of benefit to the engine room, and so the temperature rise in the engine room makes several bad conditions. This paper proposes that hot air in engine room is evacuated tv secondary pipe using jet pump. This paper demonstrates the structure and the effect of jet pump and useful guideline on design of area, length, and shape of secondary pipe to maximize the effect of jet pump.

• 설비공학논문집
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• 제17권2호
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• pp.183-190
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• 2005

In the process of ice-slurry making, ice adhesion on cooling wall or in narrow flow Path disturbs continuous ice formation. In this study, the effect on the ice adhesion to cooling surface by some freezing experiments was investigated, quantitatively. Three types of solutions were frozen in various coating vessels with stirring. In the experiment, the ice adhesion between cooling wall and Ice-slurry was evaluated by measuring stirring power. From the result, the stirring power of slurry mixture in PTFE-coating vessel was smaller than those in PE-coating, PFA-coating and bare SUS vessel. Especially, in EG H PG 1.S/ HD 1.5 mass$\%$ solution, the stirring power in the PE-coating vessel was smaller than that in the PFA-coating or SUS vessel.

• Structural Engineering and Mechanics
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• 제22권2호
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• pp.223-240
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• 2006

Taking into account the geometrical and material nonlinearities, an ultimate behavior of reinforced concrete cooling tower shell in hyperbolic configuration is presented. The design wind pressures suggested in the guidelines of the US (ACI) and Germany (VGB), with or without the effect of internal suction, are employed in the analysis to examine the qualitative and quantitative characteristics of each design wind pressure. The geometrical nonlinearity is incorporated by the Green-Lagrange strain tensor. The nonlinear features of concrete, such as the nonlinear stress-strain relation in compression, the tensile cracking with the smeared crack model, an effect of tension stiffening, are taken into account. The biaxial stress state in concrete is represented by an improved work-hardening plasticity model. From the perspective of quality of wind pressures, the two guidelines are determined as highly correlated each other. Through the extensive analysis on the Niederaussem cooling tower in Germany, not only the ultimate load is determined but also the mechanism of failure, distribution of cracks, damage processes, stress redistributions, and mean crack width are examined.

• 한국태양에너지학회 논문집
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• 제28권4호
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• pp.43-49
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• 2008

The purpose of this study is to present the simulation results and an overview of the performance assessment of a solar heating & cooling system by means of the $200m^2$ evacuated tube solar collector. The simulation was carried out using the thermal simulation code TRNSYS with new model of a single-effect LiBr/$H_{2}O$ absorption chiller developed by this study. The calculation was performed for yearly long-term thermal performance and for two design factors: the solar hot water storage tank and the cold water storage tank. As a result, it was anticipated that the yearly mean system efficiency is 46.7% and the solar fraction for the heating, cooling and hot water supply are about 84.4 %, 41.7% and 72.4%, respectively.

• 대한설비공학회지:설비저널
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• 제16권3호
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• pp.295-304
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• 1987

The purpose of this study is to develop a computer model for simulating the water-lit hium bromide absorption heat transformer (AHT) Including all major components and to find the flexibility in operation. The effect of source hot water temperature, cooling water temperature, useful hot water flow rate, cooling water flow rate and evaporator circulation flow rate were investigated. The coefficient of performance (COP), temperature boost $({\Delta}T\;=\;T_A\;-\;Ti)$ and concentration variations can be predicted. The performance study indicates that the performance of AHT increases for the waste hot water temperature increasing and with a decrease of the cooling water temperature. The effect on performances of useful hot water flow rape is significant except on temperature boost. Also the effects on performance of cooling water flow rate and evaporator circulation flow rate are small. It is shown that the computer program is valuable to predict the performance of absorp-tion heat transformer units at various working corditions.