• Title/Summary/Keyword: Difference Temperature

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Heat transfer of green timber wall panels (그린팀버월 패널의 열전달 특성)

  • Kim, Yun-Hui;Jang, Sang-Sik;Shin, Il-Joong
    • Korean Journal of Agricultural Science
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    • v.38 no.1
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    • pp.115-120
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    • 2011
  • 20% of total energy use to sustain temperature of building inside. In this reasons, researchers effort to improve the thermal insulation capacity with new wall system. Using appropriate materials and consisting new wall system should considered in energy saving design. OSB(Oriented strand board), Larch lining board used to consist wall system. $2{\sim}6$ Larch lining board has tongue & groove shape for preventing moisture. Comparing with gypsum board and green timber lining board as interior sheathing material, temperature difference of Green timber wall system was bigger than temperature difference of gypsum board wall system. This aspects indicate that Green timber wall system was revealed higher thermal insulation property than gypsum board wall system. Gypsum board portion transfer heat easily because temperature difference gradient of gypsum board wall system was smaller than OSB wall system. Total temperature variation shape of G-4-S and G-6-S show similar model but, temperature variation shape in green timber wall portion assume a new aspect. The purpose of this study was that possibility of thermal insulation variation and new composition of wall system identify to improve thermal insulation performance. In the temperature case, this study shows possibility of improving thermal insulation performance. Humidity, sunshine and wind etc. should considered to determine building adiabatic properties.

Heat Transfer Analysis for Asphalt Mixture Temperature Variation due to Wind Speed (풍속에 따른 포설 아스팔트 혼합물의 온도변화에 대한 열전달 해석)

  • Yun, Tae Young;Yoo, Pyeong Jun
    • International Journal of Highway Engineering
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    • v.17 no.4
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    • pp.33-40
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    • 2015
  • PURPOSES: Evaluation of the wind speed effect on the temperature drop of an asphalt mixture during construction, by using the transient heat transfer theory and dominant convective heat transfer coefficient model. METHODS: Finite difference method (FDM) is used to solve the transient heat transfer difference equation numerically for various wind speeds and initial temperature conditions. The Blasius convective heat transfer coefficient model is adapted to account for the effect of wind speed in the temperature predictions of the asphalt mixture, and the Beaufort number is used to select a reasonable wind speed for the analysis. As a function of time and depth, the temperature of the pavement structure is predicted and analyzed for the given initial conditions. RESULTS : The effect of wind speed on the temperature drop of asphalt mixture is found to be significant. It seems that wind speed is another parameter to be accounted for in the construction specifications for obtaining a better quality of the asphalt mixture. CONCLUSIONS: It is concluded that wind speed has a significant effect on the temperature drop of the asphalt layer. Although additional field observations have to be made to reflect the effect of wind speed on the construction specifications, it appears that wind speed is a dominant variable to be considered, in addition to the atmospheric temperature.

Study on the Thermography of Dysmenorreic women (월경통 환자의 체열분포에 대한 연구 (소음인, 태음인을 대상으로))

  • Kim, M.J.;Lee, I.S.;Kim, J.W.
    • Journal of Oriental Medical Thermology
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    • v.2 no.1
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    • pp.11-16
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    • 2003
  • Purpose D.I.T.I. can be used to diagnose the dysmenorrhea and prove the Oriental Medical Theory and the Sasang Constitutional Medicine concerning Dysmenorrhea. According to the Sasang Constitutional Medicine, we chose 39 dysmenorrhea patients (Soeumin 26 Patients, Taeumin 13 Patients) and expremented D.I.T.I. to find difference of chilliness and fever in the upper part of body and the lower part of body. Methods We expremented 39 dysmenorrhea patients chosena expremental group from Apr 1. 2002 to May 30, 2002. We diagnosed the constitution by Q.S.C.C. and selected six acu-points CV-17, CV-12, CV-4, G-21, B-15 and B-23. To appraise difference of temperature according to constitution we compared skin temperature of front to back. Result Mean Absolute Value of ${\Delta}T$ in body (front and back) shows significant difference. Totally the temperature of front is higher than the temperature of back. the temperature of Soeumin is higher than the temperature of Taeumin in whole. Conciusion Especially the upper abdomen area(CV-17) shows high temperature in 39 dysmenorrhea patients, the lower abdomen area (CV-4) of Soeumin shows lower temperature relatively.

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A Study on Air Temperature Difference between Windward and Leeward Side at High-rise Buildings (고층건물 풍상면과 풍하면의 기온차)

  • Jin, Ri;Cui, Hua;Yu, Jin-Hang;Ku, Hee-Yeong;Zheng, Hai-Yan;Jin, Wen-Cheng;Lee, Kyoo-Seock
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.15 no.1
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    • pp.63-71
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    • 2012
  • To investigate the air temperature difference between windward and leeward side at high-rise building area, the air temperature and relative humidity data were observed for 10 minute interval from July 9, 2011 to November 30, 2011. The observed data were compared, analyzed and examined to illustrate air temperature between windward side (H Apartment) and Leeward side (W Apartment). The diurnal and seasonal variation of air temperature difference between windward and leeward site were also investigated. After the analysis, the overheat of windward side by $0.4^{\circ}C$ irrespective short distance of two observation positions. It was also lower than those of surrounding air temperature observing stations. It is mainly due to the air temperature decreasing effects of leeward side of high rise buildings.

A Study on the Improvement of Indoor Thermal Performance of Floor Radiant Heating System Considering Valve Operation Characteristics (바닥복사 난방시스템의 밸브구동 특성을 고려한 실내 열환경 성능 개선 연구)

  • Song, Jae-Yeob;Ahn, Byung-Cheon
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.17 no.4
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    • pp.36-45
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    • 2021
  • In this study, to improve the indoor thermal environment of the radiant floor heating system, a study was conducted on the temperature change characteristics and energy consumption according to the change of the indoor air set temperature, the supply hot water temperature and the outdoor temperature. As for the control method, the on/off control and the thermal difference proportional control method proposed through previous studies were applied. In addition, in consideration of field applicability, numerical analysis was performed for the case where the indoor air temperature sensor was affected by the wall temperature. As a result, it was found that the temperature difference proportional control method is more effective for thermal comfort and energy saving than on/off control.

Factors Affecting Temperature of Urban Parks (도시공원의 기온에 영향을 미치는 요인)

  • 윤용한;송태갑
    • Journal of the Korean Institute of Landscape Architecture
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    • v.28 no.2
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    • pp.39-48
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    • 2000
  • The purpose of this study is to investigate the factors affecting temperature of urban parks to grasp the relationship between the land coverage in open space as well as the forest condition and decreasing city temperature by difference of purposed are. Futhermore, this research interpreted the relationship between wind direction, air temperature, the land coverage of the green space, the number of tree, green volume, height of tree and the mitigation of city temperature with the revolution analysis. The result of this study is that cool air in open space move leeward and decreasing city temperature is influenced by the difference of the land coverage in open space. Specifically, in order of the arbo $r_{-a}$rbor in the forest zone, the increase of the number of trees was related with temperature surrounding significantly. This study found that the use possibility of the green volume was recognized as the index of the green volume relative to air temperature surrounding. Green space of the city control area is more effective decreasing temperature than that of housing zone.

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Field Application of the Mass Concrete Utilizing Combined Method for Temperature Crack Reduction (온도균열 저감공법을 복합사용한 매스콘크리트의 현장적용)

  • Han, Sang-Yoon;Lee, Chung-Sub;Baek, Dae-Hyun;Jang, Duk-Bae;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2010.05a
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    • pp.37-39
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    • 2010
  • In this study, with new office construction site of S Construction company as subject, to solve all the problems according to reduced hydration heat and temperature crack of mass concrete used mat foundation and placing time difference, low heat combination of coarse particle cement and fly-ash and setting time difference applied AE water reducing agent, and to prevent the early frost damage caused by low outdoor temperature, a heat insulation method using double bubble sheet was conducted. As a result, it was found that hydration heat and setting time difference was reduced by applying a low heat combination and setting time difference construction method, and that the high insulation capability of the double bubble sheet was able to not only prevent the early frost damage but also reduce temperature difference between the central part and the upper part of mass concrete.

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Evaluation of Water Temperature Difference Energy of the Raw Water from Paldang Water Intake Station (수도권 팔당취수장 원수 이용 온도차에너지 부존량 조사)

  • Cho, Yong;Park, Jin-Hoon;Kim, Youngjoon;Park, Tae Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.170.2-170.2
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    • 2010
  • The amount of the heating and cooling energy of water source heat pump using the raw water from the Paldang water intake station is investigated in the study. The Han river water is conveyed in the large-size shallowly buried pipe. Averaged water temperature at the position, 27 km from the Paldang water intake station, is increased by $1.11^{\circ}C$ due to the geothermal energy transfer under the ground, therefore the raw water has more thermal energy than the river water. To estimate of the thermal energy for the raw water, it is assumed that the water source heat pump is used for the heating and cooling ventilation. When $5.0^{\circ}C$ temperature difference energy of the raw water is used in the heat pump system all the year except for the January and February in which $3.0^{\circ}C$ temperature difference energy is used. It is predicted that total 5,766.3 Tcal could be used in the metropolitan area a year, which is about 3.0% of the river water unutilized energy resources.

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Time-dependent natural convection in a glass melting furnace (유리용융로의 시간종속 자연대류)

  • Im, Gwang-Ok;Lee, Gwan-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.7
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    • pp.919-927
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    • 1997
  • The main purpose of this study is to determine bifurcation as the primary instability of a glass melting furnace. Steady-state and unsteady characteristics of natural convection in the partially open cavity as appeared in a glass melting furnace is investigated by using numerical analysis. Three types of convection, such as steady laminar, unsteady periodic or unsteady quasi-periodic convection may occur according to the temperature difference between upper two isothermal surfaces along the depth of cavity in a glass melting furnace. In the temperature difference of 150-900 K between batch and free surface, the larger the temperature difference, the weaker the convection strength and unsteadiness. Since the glass viscosity is increasing exponentially in the lower temperature, the batch freezes the thermofluidic field especially below the surface of it. If the depth of cavity is 0.5 m, the bifurcation to time-dependent natural convection may occur in the range of 60-650 K. If that is 1.0 m, it may occur in the whole range of temperature difference.

MERITS OF COMBINATION OF ACTIVE AND PASSIVE MICROWAVE SENSORS FOR DEVELOPING ALGORITHMS OF SST AND SURFACE WIND SPEED

  • Shibata, Akira;Murakami, Hiroshi
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.138-141
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    • 2006
  • In developing algorithms to retrieve the sea surface temperature (SST) and sea surface wind speed from the Advanced Microwave Scanning Radiometer (AMSR) aboard the AQUA and the Advanced Earth Observation Satellite-II (ADEOS-II), data from the SeaWinds aboard ADEOS-II were helpful. Since features of the ocean microwave emission (Tb) related with ocean wind are not well understood, in case of using only AMSR data, combination of AMSR and SeaWinds revealed pronounced features about the ocean Tb. Two results from combinations of the two sensors were shown in this paper. One result was obtained at wind speeds over about 6m/s, in which the ocean Tb varies with the air-sea temperature difference, even though the SeaWinds wind speed is fixed at the same values. The ocean Tb increases as the air-sea temperature difference becomes negative, i.e., the boundary condition becomes unstable. This result indicates that the air temperature should be included in AMSR SST algorithm. The second result was obtained from comparison of two wind speeds between AMSR and SeaWinds. There is a small difference of two wind speeds, which might be related with several mechanisms, such as evaporation and plankton.

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