• Corrosion Science and Technology
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• v.17 no.5
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• pp.218-224
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• 2018

Alloy 617 is a candidate Ni-based superalloy for intermediate heat exchanger (IHX) of a high-temperature gas reactor (VHTR), because of its good creep strength and corrosion resistance at high temperature. Small amount of impurities such as $H_2O$, $H_2$, CO and $CH_4$ are introduced inevitably in helium, as a coolant during operation of a VHTR. Reactions of material and impurities are accelerated with increase of temperature to $950^{\circ}C$ of operating temperature of a VHTR, leading to material corrosion aggravation. In this circumstance, high-temperature corrosion tests were performed at $950^{\circ}C$ in air and impure helium environments, up to 250 hours in this study. Oxidation rate of $950^{\circ}C$ in an air environment was higher than that of impure helium, explained by difference in outer oxide morphology and microstructure as a function of oxygen partial pressure. An equiaxed Cr-rich surface oxide layer was formed in an air environment, and a columnar Cr-rich oxide was formed in an impure helium environment.

• Solar Energy
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• v.12 no.1
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• pp.59-71
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• 1992

The purposes of the present study are to investigate the characteristics of heat storage and emission of the PCM($CalCl_2{\cdot}6H_2O$) panel, and to analyze the distribution of indoor air temperature in a floor heating space with PCM panels for the heating system. Two identical unit test cells sized $1.8m^W{\times}1.8m^L{\times}1.8m^H$ were built and installed with specially designed aluminium Ondol-panels. It held 1.2kg of calcium chloride hexahydrate(CCH). It was found that PCM panels could reduce the indoor air temperature fluctuations and maintain the phase changing temperature for considerably long duration, $2{\sim}3$ times longer in heating hour over no-CCH one. When the elapsed time was 6 hours, the average temperature difference between PCM panel and Ondol panel was $7.7^{\circ}C$.

• Solar Energy
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• v.17 no.1
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• pp.103-111
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• 1997

The purpose of this research is the study of characteristics of heat transfer in a heat pipe controlled by solenoid valve. A solenoid valve located to the adiabatic section between evaporator and condenser of heat pipe was used to control the valve action for effective energy transfer of the industrial exchanger machine. By the results presented in this study temperature difference between evaporator and condenser increases with increasing the temperature frequency and with decreasing the temperature amplitude. When inclination angle and flow rate of cooling water increases, the temperature amplitude is reached to the steady state rapidly with increasing the temperature frequncy.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.195-198
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• 2011

Liquid desiccant material, such as lithium chloride (LiCl) or halide slits are usually used on air conditioning application for controlling the humidity of high Outdoor Air (OA). Solar energy is usually used to heat the liquid in regeneration process of those desiccant. The mass transfer it self is driven by the temperature different between the liquid desiccant and the input air. This experiment study is analyzing the characteristic of the aqueous LiCl-air temperature different in variance specific gravity, especially in range of temperature different using the solar energy as the heat generator. The experiment has done by variating the concentration of the LiCl with specific gravity 1.210 and 1.150. For the comparison the pure water is also used. The result show that the mass transfer rate is increased in every variation as the increases of the temperature different, and the weeker aqueous solution of the LiCl the highest mass transfer coefficient.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.210-211
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• 2007

Amid booming PV(photovoltaic) industry, BIPV(Building Integrated PV) is one of the best fascinating PV application technologies. To apply PV in building, variable factors should be reflected such as installation position, shading, temperature effect and so on. Especially a temperature should be considered, for it affects both electrical efficiency of PV module and heating and cooling load in building. Transparent PV modules were designed as finished material for spandrels are presented in this paper. The temperature variation of the modules with and without air gap and insulation were compared and analyzed. The results showed that the module with air gap and insulation has a much larger temperature variation than another transparent module. The temperature of the module reached by 55degree C under vertical irradiance of lower 500$W/m^2$. And the temperature difference between these modules was about 15degree C. To analyze the output performance of module according to temperature variation, separate module was manufactured and measured by sun-simulator. The results showed that 1 degree temperature rise reduced about 0.45% of output power.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.714-719
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• 2018

We investigated the effects of water temperature on physiological parameters in the chicken grunt Parapristipoma trilineatum. At high temperature, the aspartate aminotransferase (AST) and the alanine aminotransferase (ALT) levels were increased, suggesting that high temperature induced hepatic damage. In addition, total protein (TP) was high at high water temperatures, which were considered stressful in the breeding environment. At high water temperatures, triglycerides (TG) were low due to increased metabolic activity, which decreased the blood TG levels as TG were used as an energy source. There was no significant difference in the plasma osmolality or the blood ion concentrations with water temperature. In generally, lysozyme, a factor in innate immunity, increased with water temperature. However, lysozyme activity tended to decrease with increasing water temperature, but the difference was not significant. These results suggested that the decrease of biophylaxis at high temperature was affect the growth or survival of the population.

• Journal of the Korean Solar Energy Society
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• v.34 no.3
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• pp.107-114
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• 2014

Modular systems are widely used in various building types including housing, dormitory, and barracks. Steel studs have many advantages over other materials as construction components of modular buildings in terms of seismic performance, durability and maintenance. However, steel stud modular systems also have weakness in condensation resistance due to high thermal conductivity of steel. The purpose of this study is to investigate the condensation resistance of steel stud wall corner details in modular buildings by thermal simulation. The condensation resistance was evaluated by temperature difference ratio according to ISO 13788. The result showed that there was little difference between the alternatives of adding cavity and insulation. Separation of interstitial steel studs showed outstanding effect on the improvement of temperature difference ratio.

• International Journal of High-Rise Buildings
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• v.2 no.4
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• pp.315-321
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• 2013

This building is a first-class super-high office building. This article briefly introduces energy-saving technique and measures adopted in HVAC system, such as cooling and heat sources, water and air system etc.

• Journal of the Korean Solar Energy Society
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• v.37 no.1
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• pp.71-80
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• 2017

A Data center houses a large number of server computers, storage and etc in racks. With the rapid increase of heat generation rates per rack in a data center, energy consumption rates for cooling have been increased year by year. In this study, energy conservation effects of a MOA (multi-stage outdoor air enabled) cooling system in a data center has been investigated when it is applied to 5 different locations, Korea. As results, Energy conservation effects of the MOA cooling system was achieved at about 20% to 30%. Humidifier operation time was 40 to 55 days when supply air temperature was maintained at 13, and humidity condition was kept within the allowed range even though humidifier was off. Furthermore, humidification was not needed when supply air temperature was maintained at $25^{\circ}C$. In selected 5 locations in Korea, the difference of regional climatic conditions affected no more than 5% in cooling energy consumption rates.

• Solar Energy
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• v.19 no.4
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• pp.11-20
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• 1999

The study on ice thermal storage system is to improve total system performance and increase the economical efficiency in actual air-conditioning facilities. To obtain the high charging and discharging efficiencies in ice thermal storage system, the improvement of thermal stratification is essential, therefore the process flow must be piston flow in the cylindrical type. In the influence of the inlet port type, the inflowing water in the distributor type diffuses through the whole storage tank more than in the slot type. In case of the flow process in the ice storage tank, the upward flow type in the charging process and the downward flow type in the discharging process make the stratification well, thereby the loss of energy wored be smaller. The influence of the inlet temperature difference and the change of the inlet flow rate is intensive when the temperature difference is larger, the flow rate is smaller in case of charging and the results are opposite in case of discharging with the reason that the good coduction condition. The total effeciency of the ice thermal storge system is 73% on condition that the porosity in the thermal storage tank is 0.55. This result shows that cylinderical ice storage tank has better storage capacity than rectangular type in case of the same porosity.