• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.111-113
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• 2007

Thermal conductivities of copper thin films on silicon wafer was obtained from temperature distribution on the surface of wafer measured by radiation thermometry, when sample was heated with constant temperature ate the both ends in a vacuum and dissipate heat by radiation heat transfer into an environment.

• Journal of Biosystems Engineering
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• v.15 no.1
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• pp.14-22
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• 1990

For efficient use of solar energy in plastic greenhouse, thermal storage system was developed. The system was constructed with the counter-flow type air-water heat exchanger using a thin polyethylene film as a medium of heat exchange parts. Experiments were carried out to investigate the heat exchange rate, optimum water flow rate, overall heat transfer coefficient, and the effectiveness of the counter-flow type air-water heat exchanger with polyethylene film bags. Mathematical model to predict air temperature leaving heat exchanger was developed. The results obtained in the present study are summarized as follows. 1. Heat exchange rate in the counter-flow type air-water heat exchanger with polyethylene film bags was compared to that of polyethylene film. Heat exchange rate was almost identical at air velocity of 0.5m/s on polyethylene film surface. But, heat exchange rate of heat exchanger with polyethylene film bag was $32{\sim}55KJ/m^2$ hr higher than that of polyethylene film at air velocity of 1.0m/s. 2. Considering the formation of uniform water film and the sufficient heat exchange rate of polyethylene film bags, optimum water flow rate in polyethylene film bags was $3.0{\sim}6.0{\ell}/m^2$ min. 3. The overall heat transfer coefficient of polyethylene film bags was found to be $35.0{\sim}130.0KJ/m^2\;hr\;^{\circ}C$ corresponding to the air velocity ranging 0.5 to 4.0 m/s on polyethylene film surface. And the overall heat transfer coefficient showed almost linearly increasing tendency to the variation of air velocity. 4. Mathematical model to predict air temperature leaving the heat exchanger was developed, resulting in a good agreement between the experimental and predicted values. But, the experimental results were a little lower than predicted. 5. Effectiveness of heat exchanger for the experiment was found to be 0.40~0.81 corresponding to the number of transfer units due to the variation of air velocity ranging 0.6 to 1.7 m/s.

• 한국해양학회지
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• v.11 no.2
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• pp.43-50
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• 1976

The annual nariation of surface heat exchange at ten selected station in the Korean coastal seas was studied using data of monthly mean surface temperature and meteorological parameters averaged for many years. Through heat exchange between the sea and the atmosphere, the surfaces in the Korean coastal seas are warmed by accepting heat from the atmosphere during march to September in the west coast sea, during Aprill to August in the south coast sea which includes the Ulleung-do coast sea and during April to September in the east coast sea. The periods which are cooled by losing heat to the atmosphere correspond to residual months excepting the above warming periods. Maximum total heat exchange during the warming period at each station shows the distribution of 320-720cal/ $\textrm{cm}^2$ day in June to July and during the cooling period shows the distribution of -260∼-940 cal/$\textrm{cm}^2$ day in November to January. The annual average total heat exchange shows warming of 100-240 Cal/$\textrm{cm}^2$ day in the west coast sea, cooling of -90∼-150 Cal/$\textrm{cm}^2$ day in the south coast sea and the Ulleung-do coast sea, and slight warming or cooling of -15∼65 Cal/$\textrm{cm}^2$ day in the east coast sea. Maxima or minima of the surface temperature in the Korean coastal seas appear in the month that the warming or cooling period is ended. The evaporation rate is highest during October to next January with the distribution of 5∼12mm/day.

• Journal of the Korean Home Economics Association
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• v.24 no.2
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• pp.75-82
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• 1986

This study was measured experimentally the Configuration factor of the adult female with the purpose of explaning quantitatively the human body's radiant heat exchange in a small scale of a house. And it is a investigatio about human clothed body's heat resistance which have great influence on radiant heat exchange. The result of this study was diagrammatized the [Shape×Area Factor] for the sake of making it easy to calculate the quantity of the actual human body's radiant heat exchange, and designed a diagram to make it easy to find the value of the human clothed body's heat resistance and clothing surface temperature. Thus, this research can be used as a basic resource for not only calculating wuantitatively radiant heat exchange of human clothed body and unclothed body in the radiant heating system of low temperature but also designing the thermal environment in a room.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.535-540
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• 2003

Based on the monthly weather report of Korea Meteorological Administration (KMA) and daily sea surface temperature (SST) data from National Fisheries Research and Development Institute (NFRDl) (1991-2001), mean heat fluxes were estimated at the Gunsan harbor Net heat flux was transported from the air to the sea surface during March to early September, and it amounts to $125\;Wm^{-2}$ in average daily during May to June. During the middle of September to February, the transfer of net heat flux was conversed from the sea surface to the air with $-125\;Wm^{-2}$ in mininum value in October. Short wave radiation was ranged from 50 to $248\;Wm^{-2}$ showing maxima in April to June. Long wave radiation was ranged from 25 to $92\;Wm^{-2}$ with mininum value in June to July. Sensible heat flux denoting negative values in April to August was ranged from -30 to $72\;Wm^{-2}.$ Latent heat flux was ranged from 15 to $82\;Wm^{-2}$ with maxima in August to September. The phase of heat exchange was changed from cooling to heating in the end of February, and from heating to cooling In the beginning of September. The advective term of heat flux showed minima in April to June and maxima in November. The ratio of temperature variations was 1.37 in the sea surface process and the horizontal process by advection. This indicates that the main factor in variation of temperature at Gunsan harbor is the heat exchange process through the sea surface from the air.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.20-25
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• 1995

Surface wind field over an ocean plays a very important role not only to generate wind-driven current, but also to control heat exchange between ocean and atmosphere. However, the surface wind-field used for the ocean circulation and heat exchange is usually estimated by indirect methods because of lack of observed wind data and incomplete spatial coverage. (omitted)

• Advances in aircraft and spacecraft science
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• v.9 no.6
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• pp.493-506
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• 2022

The study presents the results of the research of heat and heat exchange processes on the heat-stressed elements of the structure of an advanced TsAGI descent vehicle. The studies were carried out using a mathematical model based on solving discrete analogs of continuum mechanics equations. Conclusions were drawn about the correctness of the model and the dependence of the intensity of heat and mass transfer processes on the most heat-stressed sections of the apparatus surface on its geometry and the catalytic activity of the surface.

• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.66-72
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• 2014

Ground source heat pump system can achieve high efficiency of performance by utilizing annually constant underground temperature to provide heat source for space heating and cooling. Generally, the depth of constant-temperature zone under the ground depends on surface heat flux and soil properties. The deeper the ground heat exchanger is installed, the higher the heat exchange rate can be acquired. However, in order to optimally design the system, it is necessary to consider both the installation cost and the system performance. In this study, performance analysis of ground source heat pump system according to the depth has been conducted through the case study.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.196.1-196.1
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• 2011

In this study, a test bed was constructed in order to evaluate thermal efficiency of the energy pile which carries out combined roles of a structural foundation and of a heat exchanger. The energy pile in this study is designed as a large-diameter drilled shaft equipped with the heat exchange pipes which configures a W-shape and an S-shape. The drilled shaft reached to the depth of 60 m whilst the heat exchange pipes were installed to about 30 m deep from the ground surface. The W-shaped and S-shaped heat exchange pipes were installed in the opposite sections of the same drilled shaft. In-situ thermal response tests were performed for both the shapes of heat exchange pipes. To avoid underestimating the thermal performance due to hydration heat of concrete inside the drilled shaft, the in-situ thermal response tests for the energy pile were performed after four weeks since the installation of the energy pile.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.5
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• pp.598-606
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• 1988

The radiation heat-transfer coefficient is generally used to calculate radiant heat exchange of heating space. The coefficient is evenly adopted in most cases, but it is not correct in actual cases. The purpose of this paper is to grasp the changing aspect of radiation heat-transfer coefficient needed for heating load calculation of radiant heating space. Surface temperatures are measured in an Ondol space, and the coefficients are derived and examined. Gebhart's Absorption Factor Method is used for the calculations of the rates of instantaneous radiant exchange in the room. As the result, it is confirmed that the coefficients are variant according to surface temperatures, and proper coefficients are needed for each of conditions.