• 대한기계학회논문집B
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• 제23권2호
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• pp.281-287
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• 1999

The turbulent natural convection in the membrane type LNG carrier cofferdam with heating points has been studied by numerical method. As the numerical methods, we introduced the three turbulence model, a standard $k-{\varepsilon}$ model and two case of a low Reynolds number models. The parameters considered for this study ore number and capacity of heating points i.e., $1{\leq}Ns{\leq}12$ and $1.0{\times}10^5{\leq}Qs(W/m^3){\leq}1.0{\times}10^8$. The results of the isotherms and velocity vectors have been represented for various parameters. The temperature and velocity at upper position in the space ore shown to be higher than those at lower position. For obtaining the optimal temperatures, $20{\sim}30^{\circ}C$ in the cofferdam space, the heating capacities show $2.0{\times}10^7W/m^3$ at g-heating points and $1.0{\times}10^7W/m^3$ at 12-points. The mean temperature in the cofferdam space can be expressed as a function of number and capacity of heating points.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1993년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.2-2
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• 1993

The present status of the thennomechanica1 evaluation of functionally gradient materials(FGMs) for space plane application was reviewed, in which research activities and the cooperation of the national project team organized to study FGM science were demonstrated. The project team was divided into three working groups; de singing, processing and evaluation, each of which had their own tasks in the project cooperation. The testings details of the various thennomechanical tests for the FGM samples fabricated by the processing groups were described, along with their corresponding heating conditions of the real environments in the space plane application. For small-sized samples, laser beam heating test and burner heating test were well applied to study the heat shielding and heat resisting properties. Arc-heated wind tunnel test and high temperature!high velocity gas flow test were used for large-sized panel assemblies having cooling structures. The criteria for the evaluation of the heat shielding and heat resisting properties of the FGMs, as well as a crack activation mechanism in their differential temperature heating, were proposed on the basis of the observation in the burner heating test.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.105-112
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• 2007

Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4$\sim$0.8 h-1 under the condition of outdoor temperature $5^{\circ}C{\sim}-5^{\circ}C$, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses.

• 천문학회지
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• 제56권2호
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• pp.225-229
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• 2023

We investigated an emerging magnetic loop dynamically formed on the Sun, which has the effective footpoint heating source that may play a key role in heating a solar atmosphere with free magnetic energy in it. It is suggested that the heating source could be related to local compression of a plasma in the emerging loop by means of Lorentz force, which converts the magnetic energy to the internal energy of the plasma that is used to reaccelerate a decelerated downflow along the loop, eventually generating the source when the kinetic energy of the downflow is thermalized. By analyzing very high-cadense data obtained from a magnetohydrodynamic simulation, we demonstrate how the local compression is activated to trigger the generation of the heating source. This reveals a characteristic of the emerging loop that experiences a dynamic loop-loop interaction, which causes the local compression and makes the plasma gain the internal energy converted from the magnetic energy in the atmosphere. What determines the characteristic that could distinguish an illuminated emerging loop from a nonilluminated one is discussed.

• 설비공학논문집
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• 제9권2호
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• pp.180-188
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• 1997

The theoretical analysis and experiment with simulator were performed to obtain the temperature distributions in radiant heating panel and heat supply from hot water to heating space for the purpose of the development of comfortable living space from a point of view of the improvement of air quality and the enhancement of system efficiency. The relations of various parameters, such as pipe pitch, room temperature as well as flow rate and temperature of hot water and so on, with the rate of heat supplied, mean temperature and maximum temperature difference at panel surface were discussed. The effects of these parameters were also verified on the thermal performance of heating panel using the relations which could be used for the optimal design and operation of the radiant heating panel.

• 생물환경조절학회지
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• 제10권4호
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• pp.213-218
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• 2001

2000년 말 현재 전국 시설 재배면적은 52,189 ha이고 이중 가온 재배면적은 13,621 ha이다. 난방비용이 경영비중 차지하는 비중이 시설재배의 선진국의 15%에 비하여 25~30%을 차지하고 있어 난방비의 비중이 높다. 이러한 문제점을 해결하고자 가온시 시설의 난방공간을 최소화 할 수 있는 장치를 개발하여 처리별 환경 및 작물의 생육상태 및 연료소비량을 조사하였다. 시설내 난방용적을 보면 관행커튼이 661.5m$^3$에 비하여 상하이동 수평커튼은 264m$^3$로 약 60%을 줄일 수 있다. 시설억제 재배에 있어서 처리별 연료 소비량은 관행에 비하여 상하이동 커튼 설치시 28%, 그리고 반촉성 재배시에는 56%의 연료 절감의 효과가 있었고 추가로 시설내 온도 분포와 상대습도가 균일하였다. 상하이동 커튼구가 관행에 비하여 고추의 개화시기가 빨랐고 수확량도 증가하였다.

• Geomechanics and Engineering
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• 제23권4호
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• pp.393-403
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• 2020

We design the Green-Naghdi model type III (GN-III) with widespread thermoelasticity for a thermoelectric half space using a memory-dependent derivative rule (MDD). Laplace transformations and state-space techniques are used in order to find the general solution for any set of limit conditions. A basic question of heat shock charging half space and a traction-free surface was added to the formulation in the present situation of a traveling heat source with consistent heating speed and ramp-type heating. The Laplace reverse transformations are numerically recorded. There are called the impacts of several calculations of the figure of the value, heat source spead, MDD parameters, magnetic number and the parameters of the ramping period.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.497-501
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• 2009

Effect of angle of supply air on cooling and heating performances of office space is studied by numerical simulation. For a constant air volume(CAV) air-conditioning system, air is supplied vertically($90^{\circ}$) and horizontally($10^{\circ}$). Due to buoyancy, the supply angle affects the performance of cooling and heating. In cooling, since the cold supply air tends to move downward due to its high density, horizontal supply angle is better for uniform temperature distribution. In heating, however, vertical supply angle is preferred for better mean and uniform temperature distribution.

• International Journal of Human Ecology
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• 제4권1호
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• pp.15-23
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• 2003

Jeju-do is a volcanic island located off the shore of the Korean peninsula facing the Pacific Ocean. The traditional housing styles of the Jeju Province, therefore, reflect the impact of these natural backgrounds and reveal different housing styles that are distinctive from those of mainland Korea. The purpose of this research is to analyze the peculiarities of the Ondol (floor heating system) and the kitchen space of traditional housing of Jeju Island in terms of lifestyles. This study shall employ two research methods: a literature review and field survey methods. The literature review shall focus on the observations of characteristics noted in previous studies of Jeju's private houses. The field survey shall employ field survey and interview methods originating from the ethnography of the culturological-anthropologist approach. (1) The Jeju-do Ondol system is a “Weibang-eudul” system which means one Gudul per fire hole. (2) The definition of terms for Gulmook show variations depending on the various regions on Jeiu-do. (3) Major facilities in Jeongji include Gulmook, Sotduck, and Busup. Gulmook is a heating facility and Sotduck refers to a cooking facility; Busup refers to a combination of heating, cooking, and illuminating facilities.

• Design & Manufacturing
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• 제14권4호
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• pp.17-24
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• 2020

Products for heating indoors in low temperature and dry winter are largely divided into products using fossil fuels and products using electricity. The fossil fuels can warm the entire space by convection, but there is a high risk of fire and the frequent ventilation due to the increase in carbon monoxide and carbon dioxide. Heaters using electricity are mainly used because they are convenient to use and are cheap. However, these products can not efficiently warm the air because they use radiation energy. In other words, only the front part exposed to the heater is warm, and the rear part has no heating effect at all. Also, because it emits a large amount of light, fatigue of the eyes is very high. Another problem is that when using electric heaters, the room tends to be dry by high heat. Indoor humidity maintenance is a very important factor in the prevention and treatment of respiratory diseases. Especially, it is essential for health care for infants, bronchial organs and people with weak respiratory because humidity is low in winter. In this study, we conducted a study to develop a product that can improve heating efficiency while maintaining proper indoor humidity by combining heat energy and moisture particles. The concept of humidification and heating at the same time, moisture particles generated in the humidifier pass through the heater, include thermal energy, and the moisture particles with thermal energy are diffused into the space by forced convection, thereby warming the entire space. In addition, the heating time is shortened as the feeling temperature is increased with the high relative humidity, and this has the effect that the heating cost in winter is reduced.