• 설비공학논문집
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• 제23권5호
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• pp.327-333
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• 2011

In the present work, a new freeze protection method has been proposed for a natural circulation system of solar water heater. Though electrothermal wire is popularly used for the purpose, there are freezing troubles by wire cut-off and shortage of excessive electric power consumption. In the experimental device, hot water in storage tank was used to heat the outlet pipe from the tank if the pipe surface temperature falls lower than a set point. The cold water pipe to the storage tank was installed to directly contact the hot water pipe surface temperature rose by transferred heat.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.128-129
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• 2015

Al-rich coatings were prepared on hot rolled low carbon steel by hot dipping method in molten Al-bath to investigate the corrosion resistance with the possible outcomes and defects of aluminized coatings in air and $Ar-0.2%SO_2$ mixed gases. Coating microstructure was composed of an inner Al-Fe intermetallic layer and outer Al-rich layer. Aluminum oxidized preferentially to the thin, outer, protective ${\alpha}-Al_2O_3$ layer, without forming the nonprotective iron/sulfur-oxide layer after heating at $800^{\circ}C$ for 20 h, in both the gases and provided the resistance against corrosion.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.122-122
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• 2015

Al-rich coatings were prepared on hot rolled low carbon steel by hot dipping method in molten Al-bath to investigate the corrosion resistance with the possible outcomes and defects of aluminized coatings in air and $Ar-0.2%SO_2$ mixed gases. Coating microstructure was composed of an inner Al-Fe intermetallic layer and outer Al-rich layer. Aluminum oxidized preferentially to the thin, outer, protective ${\alpha}-Al_2O_3$ layer, without forming the nonprotective iron/sulfur-oxide layer after heating at $800^{\circ}C$ for 20h, in both the gases and provided the resistance against corrosion.

• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 1999년도 정기총회 및 학술논문발표요지
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• pp.1-4
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• 1999

본 연구에서는 시설원예용 하우스의 난방방식별 온열환경특성 즉, 온도 분포상의 문제점을 파악하고, 하우스 난방시스템 선정 및 하우스 설계를 위한 기초자료를 제공하기 위하여 동일 부지에 동일한 형상으로 조성된 단동 하우스에 각각 심야전력 전기히터, 경유 보일러에 의한 온풍난방, 무가온 상태로 설정하여 하우스내 온열환경에 관한 분포특성을 검토하였다. (중략)

• 설비공학논문집
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• 제22권7호
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• pp.419-428
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• 2010

This paper presents the optimization process of liquid desiccant cooling system using LiCl aqueous solution as a working fluid. Operating conditions(mass flow rate, conditioner outlet concentration, difference concentration) and design factors for heat exchangers(difference temperature of the district heating water, leaving temperature difference of the conditioner, leaving temperature difference of the regenerator, air temperature difference of the conditioner, air temperature difference of the regenerator) were optimized by response surface method. As a result, we obtained the 7.297 kW of cooling capacity and 0.788 of COP at optimized condition. Effect of difference temperature of hot water on system performances was also examined. As difference temperature of the district heating water increases, the cooling capacity increases and COP decreases.

• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 1999년도 학술발표논문집
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• pp.100-103
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• 1999

온풍난방은 우리 나라 대부분의 온실난방지역에서 가장 많이 채택하고 있는 온실난방방법으로 간주되고 있다. 온풍난방은 기본적으로 화석연료를 연소열로 변환시켜 온실난방에 사용하는 방법으로 온수난방, 태양열난방 보다 열효율이 높다. 가장 보편적 온실난방열원으로는 경유나 보일러등유를 연소실에서 연소하여 열교환기를 거친 후 온풍기의 상부에 부착되어 있는 송풍팬으로 강제적으로 온실 내로 온풍을 불어넣는다. (중략)

• 한국산업융합학회 논문집
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• 제3권4호
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• pp.307-317
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• 2000

The purpose of this study is to form a calculation formula of the mean skin temperature on the human body in a heated room by the use of floor heating system. Korean traditional floor heating system is a long way from being defunct. The floor heating systems based on hot water have been coming into wide use mainly in the apartment house. However, it is considered that the design process and evaluation method for the floor heating systems in the standpoint of human being are not established so far. In the floor heating systems, air temperature as well as floor temperature should be considered as physical factors which affect the sensation of human body. Furthermore, extremely few studies have been performed on the sitting with legs crossed posture sedentary which is the typical dwelling life style of residents from the ancient times in Korea, while a large number of studies on the influence of the floor heating systems on the human body in standing and sitting on a chair sedentary have been carried out. Especially, it is essential to elucidate how mean skin temperature on the human body is affected by thermal conduction in the contact area between the sitting with legs crossed posture sedentary human body and floor including thermal radiation due to the combination of air temperature and floor temperature, but the studies dealt with such issues have hardly been performed. Based on the above statements, the influence of the environment condition due to the combination of air temperature and floor temperature is discussed in the present investigation through theoretical of mean skin temperature on the human body in the floor heating systems.

• 설비공학논문집
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• 제25권11호
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• pp.585-594
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• 2013

In this study, we developed a heat supply control algorithm that minimizes the heat loss in the heat distribution pipelines used for supplying heat energy to shared group housing. Controlling the temperature and flow rate of the hot water supplied to the heat exchanger for shared group housing enables us to develop a heat supply control technique that meets the heating load required by each household in a shared apartment building in accordance with changes in the outdoor air temperature, and that minimizes the heat loss occurring in the heat distribution pipeline. A one-year study in 2008 on a 1,473-household D-apartment building in Hwaseong, Gyeonggi-do, South Korea, compared the heat capacity used by each household, as well as the heat capacity supplied to the heat exchanger room of the apartment housing building, to calculate the amount of heat loss in the heat distribution pipeline. The results confirmed that 24.1% of the heat supplied was lost in the piping.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.69-76
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• 2002

The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial and the radial temperature distribution in internal spare of a tube. From the study, fellowing conclusive remarks 7an be made. First, As the number of nozzles increase, separation point move into the hot exit. Second, When we use guide vane type nozzle, the axial temperature distribution constant over the 0.75 of air mass flow rate radio. Third, When we use Spiral type nozzle, axial and radial temperature distribution in the inner space is higher than another nozzle. Fourth, Axial and radial temperature distribution in the inner space vortex-tube is determined by separation point. And separation point is moved by changing of air mass flow rate ratio. At last, A heating apparatus is possible far vortex-tube to use.

• 한국지열·수열에너지학회논문집
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• 제15권3호
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• pp.14-20
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• 2019

In this study, the technologies and regulations for distributing standing column well(SCW) ground source heat pump systems to the residential cluster homes were investigated. They have only been installed in the public or commercial building having different load pattern and site structure compared with the residential cluster homes. Some of SCWs for the residential cluster homes should be installed under the basement due to a lack of site area. There are pressure differences between the SCWs installed under ground surface and basement. It is needed to develop the technology or devices to prevent overflow caused by pressure difference among the SCWs. In addition, heat balance algorithm between SCWs should be adopted to maximize the system efficiency. A heat pump having heating, cooling, hot water, heating-hot water, and cooling-hot water modes should be developed for adopting an individual air-conditioning system to the residential cluster homes.