• Title/Summary/Keyword: Wind heating

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Variation of the Overall Heat Transfer Coefficient of Plastic Greenhouse Covering Material (플라스틱온실 피복재의 관류열전달계수 변화)

  • Lee, Hyun-Woo;Diop, Souleymane;Kim, Young-Shik
    • Journal of Bio-Environment Control
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    • v.20 no.2
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    • pp.72-77
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    • 2011
  • The objective of the present study is to provide the basic data necessary for estimating the overall heat transfer coefficient of commercial plastic greenhouse. The heat flow through covering of greenhouses was measured and the variation of overall heat transfer coefficient was analyzed. Because the inside-outside temperature difference of greenhouse to indicate the stabilized overall heat transfer coefficient was different depending on the number of covering layers, the actual overall heat transfer coefficient should be decided in range of inside-outside temperature difference to make the coefficient constant for each covering method. The variation trend of the overall heat transfer coefficient according to the inside-outside temperature difference corresponded with the existing research results, but the specific values of temperature difference to present the stabilized overall heat transfer coefficient were different each other. The increase rates of overall heat transfer coefficient with wind speed were quite dissimilar among several research results and the quantity of heat loss through covering according to the wind speed in the double layers covered or curtained greenhouse was less than that in the single layer covered greenhouse. Because there was large variations among the values of overall heat transfer coefficient for the polyethylene film greenhouses, it was required to establish the standardized environmental condition for experiment measuring heat flow through covering in commercial greenhouse.

Some Important Summer Oceanogaphic Phenomena in the East China Sea (夏季 東支那海의 重要한 海洋學的 現象들)

  • 박영형
    • 한국해양학회지
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    • v.20 no.1
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    • pp.12-21
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    • 1985
  • In this paper, the most important oceangraphic phenomena of the summer season in the East China Sea are reviewed. The hydrographic conditions in the suface layer above the seasonal thermocline are under great influence from solar heating, fresh water runoff mainly from the Yangtze River, and summer wind fields. In the lower layer below the thermocline, several distinct water masses e.g. the Kuroshio surface water, the Western North Pacific Central Water and the Yellow Sea Bottom Cold Water are intruded in response to the adjustment of the field of mass to the various dynamical processes. The frontal mixing between the intruded Yellow Sea Bottom Cold. Water and the Western North Pacific Central Water takes place in the bottom layer over the continental shelf south off Cheju Is. This mixed water probably has mush influence on the water properties of the intermediate and bottom layer around Cheju Is. and the south coast of Korea.

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Impacts of anthropogenic heating on urban boundary layer in the Gyeong-In region (인공열이 도시경계층에 미치는 영향 - 경인지역을 중심으로 -)

  • Koo, Hae-Jung;Ryu, Young-Hee
    • Journal of Environmental Impact Assessment
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    • v.21 no.5
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    • pp.665-681
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    • 2012
  • This study investigates the influence of anthropogenic heat (AH) release on urban boundary layer in the Gyeong-In region using the Weather Research and Forecasting model that includes the Seoul National University Urban Canopy Model (SNUUCM). The gridded AH emission data, which is estimated in the Gyeong-In region in 2002 based on the energy consumption statistics data, are implemented into the SNUUCM. The simulated air temperature and wind speed show good agreement with the observed ones particularly in terms of phase for 11 urban sites, but they are overestimated in the nighttime. It is found that the influence of AH release on air temperature is larger in the nighttime than in the daytime even though the AH intensity is larger in the daytime. As compared with the results with AH release and without AH release, the contribution of AH release on urban heat island intensity is large in the nighttime and in the morning. As the AH intensity increases, the water vapor mixing ratio decreases in the daytime but increases in the nighttime. The atmospheric boundary layer height increases greatly in the morning (0800 - 1100 LST) and midnight (0000 LST). These results indicate that AH release can have an impact on weather and air quality in urban areas.

The Research of Wang HaoGu's Eum Syndrom Theory (왕호고(王好古)의 음증학설(陰證學說)에 대한 연구(硏究))

  • Cho, Byung-Il;Kim, Yong-Jin
    • Journal of Korean Medical classics
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    • v.20 no.2
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    • pp.125-135
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    • 2007
  • Eum Syndrom include symptoms which is because by the cold thingsand by the infection of SamEum of TaeEum, SoEum, GualEum in Treatise On Exogenous Febrile Diseases(傷寒論). After Wang HoGo, many medical people had proceed the research of Eum Syndrom, but recently, we have almost never or no nothing research about that. So, I want to make modern base of Eum syndrom, and researched mainly for the "YinZhengLueLi". That can be summarized like below. Eum Syndrom shows firstly red face, tremor, waist-and-leg heaviness, lastly body heaviness, fatigue, narcolepsy, congestion of the pupils because of from exogenous attack of wind-cold, impairment of spleen due to Cold things, and dew and mist and rain and damp's invation by mouth and nose, greedy of sexual desire, So, in the diagnosis of Eum Syndrom, we have to look over precisely the color and pulse, especially, by pulse. We can know that, he used the prescription which are have heating kidney function, Byuklyuksan, Jungyangsan, Huahamsan, Huiyangdan, Baneumdan etc, and the prescription which are have strengthening spleen and kidney, Bujasan, Yukgyesan, Bakchulsan etc. So, we can know that he was very interested in deficiency and cold of kidney's function. While, he newly made the prescriptions of Sinchultang, Bakchultang, Huanggitang, Jujunghuan, and he used various prescriptions.

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A Study on the Simulation of Natural Ventilation Effect for Single-sided Casement Window as Opening Types (케이스먼트 창호 개폐방식에 따른 자연환기 효과에 관한 시뮬레이션 연구)

  • Choi, Taehwoan;Kim, Taeyeon;Leigh, Seung-Bok
    • KIEAE Journal
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    • v.7 no.4
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    • pp.57-62
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    • 2007
  • At the moment, the reduction of building energy consumption is a unavoidable task of mankind for conserving global environment. Decreasing overall U-value of building envelope and air infiltration, especially in Korean climate condition with clear four seasons, are the obvious solutions for the objective. Thus low glazing ratio with small window openings are required for heating and cooling load reduction in buildings. Using larger window openings could provide better natural ventilation but it also increases the direct solar radiation penetration into indoor space, heat gain in summer and heat loss in winter. On the other hand, the ventilation rates decreasing problem with smaller window openings could be occurred. As a solution for it, the use of casement window can cause increasing natural ventilation rates by wing wall effect. This paper focuses on deduce the most efficient opening type of casement window in Korean climate. To estimate ventilation performance of each opening types, CFD simulation was used. The best performance of opening type in every wind direction is opening both windows to the center and the most appropriate opening type for Korean climate is also opening both windows to center.

An asymptotic analysis of the Taylor-Proudman flow in a rapidly-rotating compressible fluid (압축성 회전유체에서 발생하는 Taylor-Proudman 유동에 대한 점근해석)

  • Park Jun Sang;Hyun Jae Min
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.341-344
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    • 2002
  • A matched asymptotic analysis is conducted for a compressible rotating flow in a cylindrical container when a mechanical and/or a thermal disturbance is imposed on the wall. The system Ekman number is assumed to be very small. The conditions for the Taylor-Proudman column in the interior, which were also given in the companion paper Park & Hyun, 2002) by means of the energy balancing analysis, have been re-derived. The concept of the variable, the energy content $e[{\equiv}T+2 {\alpha}^2 {\gamma}{\nu}]$, is reformulated, and its effectiveness in characterizing the energy transport mechanism is delineated. It is seen that, under the condition of the Taylor-Proudman column, numerous admissible theoretical solutions for interior flow exist with an associated wail boundary condition. Some canonical examples are illustrated with comprehensive physical descriptions. The differential heating problem on the top and bottom endwall disks is revisited by using the concept of the energy content. The results are shown to be in line with the previous findings.

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A Study on the ecological design elements of elementary school interior - Focused on the elementary schools of Osaka, Japan and Busan, Korea - (초등학교 실내공간 디자인의 환경친화적 특성에 관한 연구 - 부산시와 오사카시 초등학교 사례를 중심으로 -)

  • Yun Ji-Young;Song Ju-Eun
    • Korean Institute of Interior Design Journal
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    • v.14 no.3 s.50
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    • pp.46-54
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    • 2005
  • This study explored how the elementary schools provided proper interior environments to the students in terms of ecological aspects. 14 cases-7 in Busan and 7 in Osaka which were newly built or remodelled since 2000 were selected. These schools were analyzed based on the eco-school guideline suggested In the former study. The guideline categorizes into three parts: 1) energy efficiency related with lighting, ventilation, heating and insulation, 2) greening, 3) sustainability including recycling water system and use of environmentally friendly materials. The results showed that Korean schools require more systematic planning for natural lighting, ventilation, Insulation, greening and new water system while Japanese schools need use of environmentally friendly materials and consideration for natural lighting, insulation and interior greening. Especially, natural lighting and natural ventilation through roof window, atrium, wind tower and use of natural insulation and blind window system should be basically considered at the Initial planning. Also, this study reveals that ecological approach including greening and natural lighting with various architectural form should be applied in future elementary school design to make the school environment more agreeable and economical.

Study on Fresh Air Load Reduction System by Using Geothermal Energy - Effect on Thermal Characteristic arid Air Pattern of System by Opening Configuration - (지열을 이용한 공조외기부하저감 시스템에 관한 연구 -지하피트 공간 내의 개구부 형상이 시스템의 열적 특성 및 기류성상에 미치는 영향-)

  • Son Won-Tug;Lee Sung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.11
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    • pp.1092-1100
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    • 2004
  • This paper presents the effect of opening configuration on the thermal behavior and air pattern of earth tube system. The earth tube system is a fresh air load reduction system by using underground double floor space for air-conditioning. In order to analyze the effect of opening configuration on thermal performance of this system and air pattern in underground double floor space quantitatively, we used a model dealing with tree-dimensional profile of wind velocity and temperature in underground double floor space. In conclusion, it is confirmed that heat exchange of a fresh air is mainly performed with upper and lower wall in underground double floor space, and that heat exchange area increased by installing the opening near the wall.

Comparative analysis on environment control systems for glasshouses and plastic houses (유리온실과 플라스틱 온실의 환경조절시스템 비교분석)

  • Nam, Sang-Woon;Shin, Hyun-Ho;Seo, Dong-Uk;Yu, In-Ho
    • Korean Journal of Agricultural Science
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    • v.41 no.3
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    • pp.251-258
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    • 2014
  • In order to set up the basic environmental control systems which the new concept greenhouses have to equip, greenhouse characteristics, environmental management and control systems in domestic glasshouses and plastic houses were investigated and analyzed comparatively. Survey results on the width, length, eaves height, and the number of spans etc. showed that glasshouses were bigger than plastic houses significantly. New concept greenhouses claim to be plastic houses, but it will be reasonable to follow the specifications of the glasshouse. Specifications to be applied to new concept greenhouses were proposed as follows; hot water heating systems, aluminum screens as the thermal curtain, evaporative cooling systems, roof vents on the ridge, circulation fans, $CO_2$ enrichment, hydroponic systems, and automatic irrigation control systems. Environmental measurement systems for the indoor and outdoor temperature, humidity, light, wind speed and indoor $CO_2$ concentration have to be fully equipped. The automatic control system has to be as a complex environmental control system, not a single item control system. Also, for stable dissemination, domestically producing complete greenhouse control system should be made as soon as possible.

A Development of Counter Flow Type of Cooling System for Effective Panel Cooling (효과적인 패널 냉각을 위한 대향류형 냉각장치의 개발)

  • Lee, Joong-Soon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.3
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    • pp.802-807
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    • 2010
  • The high efficient and cooling system is very important to the control panels of electrical distributors, and Industrial automated system including computer. Also, it can be used widely in various industrial systems such as industrial robots, numerically controlled machining center, and so on. The cooling method which flowing gasses were forced to circulate by compulsion was adapted in this study. then development of counter flow type of cooling system for effective panel cooling. In the present study, fin assembly was developed for this cooling system. As results, the developed system has the improvements of cooling performances and radiant heat ratio. Its increasing of airflow mass is about 20%, and radiation rate of heating is twice or more as high as the conventional system.