• Title/Summary/Keyword: daytime temperature

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SST Effect upon Numerical Simulation of Atmospheric Dispersion (대기확산의 수치모의에서 SST 효과)

  • 이화운;원경미;조인숙
    • Journal of Korean Society for Atmospheric Environment
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    • v.15 no.6
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    • pp.767-777
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    • 1999
  • In the coastal region air flow changes due to the abrupt change of surface temperature between land and sea. So a numerical simulation for atmospheric flow fields must be considered the correct fields of sea surface temperature(SST). In this study, we used variables such as latent heat flux, sensible heat flux, short and long wave radiation of ocean and atmosphere which exchanged across the sea surface between atmosphere and ocean model. We found that this consideration simulated the more precise SST fields by comparing with those of the observated results. Simulated horizontal SST differences in season were 2.5~4$^{\circ}C$. Therefore we simulated the more precise atmospheric flow fields and the movement and dispersion of the pollutants with the Lagrangian particle dispersion model. In the daytime dispersion pattern of the pollutants emitted from ship sources moved toward inland, in the night time moved toward sea by land/sea breeze criculation. But air pollutants dispersion can be affected by inland topography, especially Yangsan and coastal area because of nocturnal wind speed decrease.

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Water Requirement for Crops by using Meteological data (기상자료에 의한 작물의 필요수량 결정)

  • 이중기
    • Water for future
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    • v.6 no.1
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    • pp.87-99
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    • 1973
  • The calculation of the comsumptive use by crop can be most accurate when it is actually measured. The mankind is not yet able tole grasp all the natural conditions or phenomena. The induces of actual measurement at a representive observatory and the formula abtained from the area werowere made as close as possible, which is called as the Blaney Criddle formcula, published in 1945. In calculating the water require-ment of consumptive use of water by farm crops, a more accurate and reasonable formula should be induced as the factors other than temperature and day-time hours according to the location of project area have also influences. The formula of Mr. Jerald E. Christianen published in 1969 is based on the induces of the records of actural measurements for 3, 928 months at 80 different stations and his formula couers a wider range of functions that calculate water requirement to induce the functions of moisture, wind, velocity, sunshine at elevatons, in addition to temperature and daytime hours in accordance with latitude and was modified to be fit to natural phenomena. The formula is being widely in use in many contries with their modification since it is worth while for usealso in korea, the formula is introduced and explained in the following.

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Relationship between Thermal Low and Long-Range Transport of Air Pollutants (대기오염물질의 장거리 수송과 열적저기압의 관계)

  • 이화운;김유근;김해동;정우식;현명숙
    • Journal of Environmental Science International
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    • v.10 no.2
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    • pp.143-151
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    • 2001
  • The atmospheric conditions and the transport mechanism of long-range transport of air pollutants from coastal area to inland area were investigated using regular meteorological data and air pollution data obtatined from the southeastern area of Korea. Daytime temperature over the inland area(Taegu) was higher than that over the coastal area(Pusan) and the temperature difference of about 5~6$^{\circ}C$ when the thermal low most fully developed and the sea level pressure over Taegu was lower than that over Pusan by about 4~5hPa at that time. Therefore this low pressure appeared to the thermally induced low. Air mass polluted from the coastal area during the morning period was transported inland area, at first by the sea breeze and by the large scale wind system toward the thermal low generated in the mountainous inland region. This was explained by the fact that the concentration of air pollutants over Taegu increased throughtout the late afternoon.

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A change of local meteorological environment according to dam construction of Nakdong-River -II. Estimation using numerical model- (낙동강 수계 중의 댐 건설에 의한 주변의 국지기상환경 변화 -II. 수치모델을 이용한 추정-)

  • 전병일;이영미
    • Journal of Environmental Science International
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    • v.11 no.4
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    • pp.281-288
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    • 2002
  • This study was carried out for reading the change of local meteorological environment according to dam construction of Nakdong-river using numerical model. The study used PSU/NCAR Mesoscale Model version5(MM5) for inquiring effect of formation of artificial lake after dam construction. The colleague simulated temperature mixing ratio, latent heat flux and sensible heat flux in two cause of existing lake and not. Temperature and mixing ratio in southwest of Andong lake increased because of the air that was warm and moist above the lake moved to southwest due to the northeasterly wind. In the case of existing lake around Andong, latent heat flux increased much in the daytime after sunrise. However, sensible heat flux decreased but it didn't change distinctly in southwest of Andong like the other values.

Development of Bin Weather Data for Simplified Energy Calculations (간역열부하계산용(簡易熱負荷計算用) Bin기상(氣象)데이터)

  • Kim, Doo Chun;Choi, Jin Hee
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.17 no.1
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    • pp.28-43
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    • 1988
  • The purpose of this research is to produce bin weather data for Seoul from Standard Weather Data. The intended use of these data is for input to recently developed models for simplified energy calculations and for generating variable-base degree-day information. The data produced under this study include $3^{\circ}C$ bin data covering the full range of dry-bulb temperatures with mean coincident wet-bulb and daytime coincident solar radiation, wet-bulb bins down to freezing temperature, wind speed bins with prevailing directions, and heating and cooling degree hours to nine different temperature bases. All of these data are tabulated in six separate time periods and total daily categories for monthly and annual periods.

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A Proposal for the Future of Summer in the Dosshouse (쪽방촌의 여름철 더위해결을 위한 방안 제시)

  • You, Nam Gyu;Kim, Min Sung;Kim, Bong Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.102-103
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    • 2019
  • There are about 3,500 people living in the Seoul Dosshouse, including Namdaemun, Dongdaemun, Donui-dong, Changshin-dong, and Yeongdeungpo. The daytime temperature in the Dosshouse is 43 degrees and the indoor temperature is 35 degrees, which is also higher than the surrouding area. Most of them live in one-person the poor strata, where they have been fighting the heat and the summer. The old building is closely located and a 1.5-pyeong room without windows is a hot environment. Water, air-conditioning is difficult or impossible for people who are economically inferior and cannot solve their own solutions. The solution that can be provided by the country is to heat up once or twice a day by fire hose or shelter. However, there are many patients with discomfort, the distance is far, and the effect is insignificant. Therefore, through this experiment by using discarded banner, I would like to suggest a way to solve the summere heat of the Dosshouse.

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Actual Energy Consumption Analysis on Temperature Control Strategies (Set-point Control, Outdoor Temperature Reset Control and Outdoor Temperature Predictive Control) of Secondary Side Hot Water of District Heating System (지역난방 2차측 공급수 온도 제어방안(설정온도 제어, 외기온 보상제어, 외기온 예측제어)에 따른 에너지사용량 실증 비교)

  • Cho, Sung-Hwan;Hong, Seong-Ki;Lee, Sang-Jun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.3
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    • pp.137-145
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    • 2015
  • In this study, the actual energy consumption of the secondary side of District Heating System (DHS) with different hot water supply temperature control methods are compared. Three methods are Set-point Control, Outdoor Temperature Reset Control and Outdoor Temperature Prediction Control. While Outdoor Temperature Reset Control has been widely used for energy savings of the secondary side of the system, the results show that Outdoor Temperature Prediction Control method saves more energy. In general, Outdoor Temperature Prediction Control method lowers the supply temperature of hot water, and it reduces standby losses and increases overall heat transfer value of heated spaces due to more flow into the space. During actual energy consumption monitoring, Outdoor Temperature Prediction Control method saves about 7.1% in comparison to Outdoor Temperature Reset Control method and about 15.7% in comparison to Set-point Control method. Also, it is found that at when partial load condition, such as daytime, the fluctuation of hot water supply temperature with Set-point Control is more severe than Outdoor Temperature Prediction Control. Therefore, it proves that Outdoor Temperature Prediction Control is more stable even at the partial load conditions.

Analysis of Solar Energy Storage Using Effectiveness on Single Span Plastic Greenhouse with Water Curtain System (수막재배 단동비닐하우스의 태양열 축열이용 효과분석)

  • Lee, S.H.;Ryou, Y.S.;Moon, J.P.;Yun, N.K.;Lee, S.J.;Kim, K.W.
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.200.2-200.2
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    • 2010
  • This study was carried out in order to reduce the amount of underground water which is used in the water curtain system for retaining heat. To proceed to the research, two plastic green houses of water curtain system were installed. One was equipped of internal small tunnel for keeping warm air in the interior of the house. Then the internal small tunnel for keeping warm air was fitted with PVC duct of 50cm in diameter filled with subsurface water. Storing surplus solar energy in the water filled in PVC duct was the method used to this house. Another was installed with FCU in the middle of the house, and was fitted a circulation motor in water tank for heat storage which was operated from 10 a.m. to 4 p.m. in order to interchange heat with FCU. The latter was installed with four FCUs which has a capacity of 8000kcal per hour. Consequently about 5 degrees celsius could be maintained in the interior of the internal small tunnel for keeping warm air with the external temperature of more than minus 5 degrees celsius. It appeared that the alteration of an internal temperature of the house was flexible depending on the sunlight during daytime. It happened that to prevent the water from freezing, mixing antifreezing liquid in the flowing water of FCU or changing the operating method of FCU was a suitable measure. Also, in order to use the surplus solar thermal energy on plastic green house of water curtain system efficiently, storing the surplus heat during daytime simultaneously finding a method of using water curtain systematic underground water happened to be important. As a result of this research, when the house's interior temperature is below zero the operation of FCU appeared to be impossible. Therefore when supposed that the amount of water used in the house is 150~200ton for stable operation of FCU, using the system mentioned in the above research happened to be appropriate of reducing the amount of subsurface water from 80% to 100% when maintaining the interior of internal small tunnel's temperature for keeping warm air of 5 degrees celsius at the extreme temperature of minus 5 degrees celsius.

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Estimation of Surplus Solar Energy in Greenhouse (I) - Case Study Based on 1-2W Type - (온실내 잉여 태양에너지 산정 (I) - 1-2W형을 중심으로 -)

  • Suh, Won-Myung;Bae, Yong-Han;Ryou, Young-Sun;Lee, Sung-Hyoun;Yoon, Yong-Cheol
    • Journal of The Korean Society of Agricultural Engineers
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    • v.51 no.5
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    • pp.79-86
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    • 2009
  • This research performed to analyze surplus solar energy, which is generated from a greenhouse during daytime, and to make the basic materials for designing thermal energy storage system for surplus solar energy. For this goal, it analyzed the surplus solar energy coming from two types of greenhouse. The results of this research are as per the below: In the case of 1-2W-type greenhouse, this research gave the same temperature and ventilation condition regardless of regions, but it was judged that the quantity of surplus solar energy could be greatly changed, depending on the energy consumed for the photosynthesis and evapotranspiration of crops in the greenhouse, on the heating temperature during daytime and night, on the existence/non-existence of a curtain and its warming effect, and on the ventilation temperature suitable for the overcoming of high temperature troubles or for the optimum cultivation temperature. In the case of a single-span greenhouse, there was a big difference in energy incoming and outgoing by month, but throughout seasons, 85.0 % of the total energy put into the greenhouse was solar energy and the energy input by heating was just 15.0 % of the total. 26.4 % of the total energy input for the greenhouse was used for photosynthesis and evapotranspiration of crops, and 44.2 % of the remaining 73.6 % went out in the form of radiant heat through the surface of the greenhouse. That is, 25.2 % of the total energy loss was just the surplus solar energy. 67.6 % of the total heating energy was concentrically used for 3 months from December to February next year, but the surplus solar energy during the same period was just 19.4 % of the total annual quantity so it was found that the given condition was more restrictive in directly converting the surplus heat into greenhouse heating. Under the disadvantageous circumstance of 3 months from December to February next year, it was possible to supplement 28 % (December) $\sim$ 85 % (February) of heating energy with surplus solar energy.

A Case Study of Human Thermal Sensation (Comfort) in Plastic Houses (온실시설내 인간 열환경지수(열쾌적성)에 대한 사례연구)

  • Jung, Leeweon;Jin, Younghwan;Jeun, Yoona;Ko, Kyuman;Park, Hyungwook;Park, Sookuk
    • Journal of Environmental Science International
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    • v.25 no.8
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    • pp.1115-1129
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    • 2016
  • To analyze human thermal environments in protected horticultural houses (plastic houses), human thermal sensations estimated using measured microclimatic data (air temperature, humidity, wind speed, and solar and terrestrial radiation) were compared between an outdoor area and two indoor plastic houses, a polyethylene (PE) house and a polycarbonate (PC) house. Measurements were carried out during the daytime in autumn, a transient season that exhibits human thermal environments ranging from neutral to very hot. The mean air temperature and absolute humidity of the houses were $14.6-16.8^{\circ}C$ (max. 22. $3^{\circ}C$) and $7.0-12.0g{\cdot}m^{-3}$ higher than those of the outdoor area, respectively. Solar (K) and terrestrial (L) radiation were compared directionally from the sky hemisphere (${\downarrow}$) and the ground hemisphere (${\uparrow}$). The mean $K{\downarrow}$ and $K{\uparrow}$ values for the houses were respectively $232.5-367.8W{\cdot}m^{-2}$ and $44.9-55.7W;{\cdot}m^{-2}$ lower than those in the outdoor area; the mean $L{\downarrow}$ and $L{\uparrow}$ values were respectively $150.4-182.3W{\cdot}m^{-2}$ and $30.5-33.9W{\cdot}m^{-2}$ higher than those in the outdoor area. Thus, L was revealed to be more influential on the greenhouse effect in the houses than K. Consequently, mean radiant temperature in the houses was higher than the outdoor area during the daytime from 10:45 to 14:15. As a result, mean human thermal sensation values in the PMV, PET, and UTCI of the houses were respectively $3.2-3.4^{\circ}C$ (max. $4.7^{\circ}C$), $15.2-16.4^{\circ}C$ (max. $23.7^{\circ}C$) and $13.6-15.4^{\circ}C$ (max. $22.3^{\circ}C$) higher than those in the outdoor area. The heat stress levels that were influenced by human thermal sensation were much higher in the houses (between hot and very hot) than in the outdoor (between neutral and warm). Further, the microclimatic component that most affected the human thermal sensation in the houses was air temperature that was primarily influenced by $L{\downarrow}$. Therefore, workers in the plastic houses could experience strong heat stresses, equal to hot or higher, when air temperature rose over $22^{\circ}C$ on clear autumn days.