• 설비공학논문집
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• 제15권6호
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• pp.524-532
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• 2003

In this paper, a personal air-conditioning system considering the human thermal adaptability is analyzed. Although the conventional personal air-conditioner was proofed to be satisfactory in providing for the thermal comfort, it is being questioned on the term of its energy efficiency. Therefore, it is important and urgent to develop new types of personal air-conditioning system with sustainable control strategy that can ensure energy saving and thermal comfort simultaneously. In this study, we first examined the problems of the conventional personal air-conditioning system with field interview and laboratory experiment in terms of usage, management and thermal comfort, and proposed the energy-saving personal air-conditioning system considering the human thermal adaptation. Then a laboratory experiment was performed to analyze the characteristics of the human thermal comfort under severe indoor thermal conditions, which were controlled using a new personal air-conditioning unit designed according to the proposal. The results help to illustrate the alleviation effect of the new personal air-conditioning system, and indicate that the thermal alleviation time is useful to maintain the thermal comfort with efficient usage of energy.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.149-154
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• 1999

The influences of air staging on NOx emission and burnout of coal flames were investigated using 1MWth combustion test facility. The experiments showed that variation of overall excess air ratio led to a relatively higher NOx emission level for ${\lambda}=1.2.$ When air staging was applied to the combustion air, it was confirmed that a fuel rich primary combustion zone was established and unburned char was burened completely by mixing with the staged air supplied radially around the flame. The NOx emissions were redued by increasing the staged air flow rate, and staging air was suggested to be more than 40% of the total combustion air for the substantial NOx reduction.

• 한국연소학회지
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• 제15권4호
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• pp.1-8
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• 2010

Mild combustion is considered as a promising combustion technology for energy saving and low emission of combustion product gases. In this paper, the controllability of reaction region in mild combustion is examined by using co-axial air nozzle. For this purpose, numerical approach is carried out. Propane is considered for fuel and air is considered for oxidizer and the temperature of air is assumed 900K slightly higher than auto ignition temperature of propane. But unlike main air, the atmospheric condition of co-axial air is considered. Various cases are conducted to verify the characteristics of Co-Axial air burner configuration. The use of coaxial air can affect reaction region. These modification help the mixing between fuel and oxidizer. Then, reaction region is reduced compare to normal burner configuration. The enhancement of main air momentum also affects on temperature uniformity and reaction region. The eddy dissipation concept turbulence/chemistry interaction model is used with two step of global chemical reaction model.

• 한국해양공학회지
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• 제14권3호
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• pp.84-89
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• 2000

The purpose of this study is to investigate the combustion emission characteristics by the effect of secondary air injection and variation of the excess air ratio in combustion field of model gas turbine combustor. For this purpose, mean temperature, CO, $CO_2$, $O_2$ and HC concentrations were measured by changing excess air ratio and secondary air injection. As a result of this study, mean temperature was decreased and CO, HC emission increased by increasing the excess air ratio of secondary air. Therefore, this results showed the secondary air injection effected strongly on the flame structure and combustion emission characteristics.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.171-176
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• 2000

This purpose of this study is to investigate the combustion emission characteristics on the effect of secondary air injection in combustion field of model gas turbine combustor changing excess air ratio. For this purpose, meantemperature, CO, CO2, O2 and HC concentration were measured by changing excess air ratio and secondary air injection. As a result of this study, meantemperature, CO2 emission was decreased and CO emission increased by increasing the excess air ratio of secondary air. therefore, This paper showed the effect of Secondary air injection on flame structure, combustion emission characteristics.

• 소성∙가공
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• 제24권1호
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• pp.20-27
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• 2015

Hot tensile tests were conducted at different temperatures ranging from $20^{\circ}C$ to $550^{\circ}C$ to evaluate the mechanical properties of Al5052 seamless tubes. Such tubes can provide the technological foundation for complex forming using hot air bulging. Hot air bulging is one of the recently developed hydroforming techniques and it has some limitations in terms of cycle times. The benefits of hot air bulging are weight and cost savings through part consolidation and reduced post-forming processes such as welding and piercing. In order to extend the forming limits of Al lightweight material hot air bulging was investigated. A heated tube was placed in a heated die and sealed at the ends by sealing cylinders. The heated tube was subsequently expanded against the die cavity wall by internal pressure using air medium. The results of the current study show that axial feeding speed and air pressure have an effect on the formability of Al tubes during air bulging at elevated temperatures.

• 설비공학논문집
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• 제16권12호
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• pp.1227-1233
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• 2004

Air handling unit (AHU)'s air filter pressure difference is important for energy consumption and indoor air quality. Both energy Performance data and air filter differential pressure of AHU in real office buildings were monitored and analyzed to investigate quantitatively energy impact as dust buildup level on air filter grows. We also modeled and simulated CAV system using HVACSIM＋ program to examine the energy effect of dust buildup on filters. Through analysis of time series pressure drop data, the filter pressure difference rate has been increased due to cumulative supply air flow rate increase. As filter pressure drop increased to 1 inch water column, it is found that the supply air flow rate was decreased by 10%, the chilled water flow rate was increased by 5.9% and the pump energy consumption was increased to 5.9%.

• 한국정밀공학회지
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• 제24권9호
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• pp.103-109
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• 2007

LCD (Liquid Crystal Display) is widely used electronic product. It needs too many processes such as PECVD (Plasma Enhanced Vapor Deposition), Sputtering, Photo-lithography, Dry etch. Each process is important but inspection process is more important because most companies emphasis on the six sigma. Recently, LCD inspection system is composed with inlet, inspector, outlet air pads. LCD is inspected on air pad which is shooting air from air hole. This paper studies on pad design of air bearing for LCD inspection to minimize LCD fluctuation. This design is able to reduce fluctuation and then satisfies CCD inspectional range. Also inspection pad needs to adequate stable area.

• 한국대기환경학회지
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• 제15권5호
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• pp.625-638
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• 1999

Air quality modeling for coastal urban region has been composed of a complex system including meteorological, chemical and physical processes and emission characteristics in complex terrain. In this study, we studied about an effect prediction for deposition phenomenon affecting on air quality in Pusan metopolitan metropolitan city. In air quality modeling including ship sources, a situation considered deposition process habe better result than not considered when compared with observed value. Air pollutants emitted into urban air during the daytime nearly removed through urban atmosphere polluted. Also these phenomena correlated concentration variation connent with sea/land breezes and terrain effect. Therefore we conclude that the concentration was low at daytime when deposition flux is high, and deposition effect on industrial complex and Dongrae region is considerable in particular.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권4호
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• pp.412-422
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• 2012

Air lubrication techniques for frictional drag reduction on ships have been proposed by numerous researchers since the 19th century. However, these techniques have not been widely adopted as questions persist about their drag reduction performance beyond the laboratory, as well as energy and economic cost-benefit. This paper draws on data from the literature to consider the suitability of air lubrication for large ocean going and U.S. Great Lakes ships, by establishing the basic energy economic calculations and presenting results for a hypothetical air lubricated ship. All the assumptions made in the course of the analysis are clearly stated so that they can be refined when considering application of air lubrication to a specific ship. The analysis suggests that, if successfully implemented, both air layer and partial cavity drag reduction could lead to net energy savings of 10 to 20%, with corresponding reductions in emissions.