• Title/Summary/Keyword: Temperature

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Analysis for Air Temperature Trend and Elasticity of Air-water Temperature according to Climate Changes in Nakdong River Basin (기후변화에 따른 낙동강 유역의 기온 경향성 및 수온과의 탄성도 분석)

  • Shon, Tae Seok;Lim, Yong Gyun;Baek, Meung Ki;Shin, Hyun Suk
    • Journal of Korean Society on Water Environment
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    • v.26 no.5
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    • pp.822-833
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    • 2010
  • Temperature increase due to climate changes causes change of water temperature in rivers which results in change of water quality etc. and the change of river ecosystem has a great impact on human life. Analyzing the impact of current climate changes on air and water temperature is an important thing in adapting to the climate changes. This study examined the effect of climate changes through analyzing air temperature trend for Nakdong river basin and analyzed the elasticity of air-water temperature to understand the effect of climate changes on water temperature. For analysis air temperature trend, collecting air temperature data from the National Weather Service on main points in Nakdong river basin, and resampling them at the units of year, season and month, used as data for air temperature trend analysis. Analyzing for elasticity of air-water temperature, the data were collected by the Water Environment Information system for water temperature, while air temperature data were collected at the National Weather Service point nearest in the water temperature point. And using the results of trend analysis and elasticity analysis, the effect of climate changes on water temperature was examined estimating future water temperature in 20 years and 50 years after. It is judged that analysis on mutual impact between factors such as heat budget, precipitation and evapotranspiration on river water temperature affected by climate changes and river water temperature is necessary.

Study on Field Observations of the Thermal Environment in the Downtown Location and the Outskirt Site (하절기 도심과 외곽지의 열특성 비교 관측)

  • Jung, Im-Soo;Choi, Dong-Ho;Lee, Bu-Yong
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.21-25
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    • 2009
  • This study is about heat island as one of the urban climate variation factors in urbanized modern society, which compared and observed the thermal characteristics both the downtown location and the outskirt site in summer. The diurnal air temperature range at each point is $12.6^{\circ}C$ in the downtown location and $14.3^{\circ}C$ in the outskirt site, so, it was found that the diurnal air temperature range in the outskirt site was $1.7^{\circ}C$ higher than in the downtown location. There was 20 minutes difference to reach the highest temperature between globe temperature and air temperature in the downtown location, however, the time spent to reach the highest temperature between globe temperature and air temperature in the outskirt site was the same. When we compared the globe temperature between the downtown location and outskirt site, we found that the temperature in the outskirt site was lower than in the downtown location after sunset due to the sudden temperature drops, although the exposed time to insolation in the outskirt site is longer. The average of globe temperature difference on the sample days was $1.1^{\circ}C$, the average of surface temperature difference on the sample days was $1.0^{\circ}C$, and the average of air temperature difference on the sample days was $2.0^{\circ}C$ Thus, it was found that the average of air temperature difference was higher than the average of globe temperature and the average of surface temperature. The result of this study is that the urban environment factors have more effect on the air temperature difference than globe temperature and surface temperature.

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Characteristics of Changes in Air and Road Temperatures Induced by Environmental Conditions in the Urban Region of Seoul Through an Intensive Observing Period (IOP) of Heatwaves in the Summer of 2023 (2023년 여름철 폭염 집중관측을 통한 서울 도심환경 조건에 따른 기온 및 노면 온도의 변화 특성)

  • Sung-Joon Na;Sang-Dae Han;Je-Won Kim;Moon-Su Park;Baek-Jo Kim
    • Journal of Environmental Science International
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    • v.33 no.1
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    • pp.75-85
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    • 2024
  • An intensive observing period (IOP) of heatwaves in the urban region of Seoul in the summer of 2023 was carried out to understand the changes in air temperature and road temperature induced by environmental conditions. The temperature observed at eight points with different urban environmental conditions was compared with the temperature by the KMA/AWS to analyze the characteristics of change in air temperature by height and the change in road temperature according to environmental conditions and road sprinkler. The comparison of the average temperature observed in different urban environmental conditions with the temperature observed at KMA/AWS showed that the air temperature in asphalt and open space sites was 0.7 to 2.3℃ higher and that the one in bus stops was 0.9 to 2.3℃ higher. In terms of temperature deviations depending on residential type, the temperature in highly populated areas was about 0.1 to 0.8℃ higher than that of apartment complexes. In addition, regardless of the size of a park, the temperature in the park was lower than the temperature in dense housing areas and apartment complexes. In asphalt and residential areas, the road temperature was higher than the temperature at a height of 150 cm, Conversely, road temperature was lower than air temperature in a shaded shelter and large park. In addition, after spraying a surface road, the road temperature immediately dropped by about 3 to 4℃; however, after about 20 minutes, it rose again to the previous road temperature. This change in road temperature appeared only for the temperature of 30 cm height.

Actual Energy Consumption Analysis of Temperature Control Strategies for Secondary Side Hot Water District Heating System with an Inverter (인버터시스템 적용 지역난방 시스템의 2차측 공급수 온도 제어방안에 따른 에너지사용량 실증 비교)

  • Cho, Sung-Hwan;Hong, Seong-Ki
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.4
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    • pp.179-186
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    • 2015
  • In this study, the actual energy consumption of the secondary side District Heating System (DHS) with different hot water supply temperature control methods is compared. The two methods are Outdoor Temperature Reset Control and Outdoor Temperature Predictive Control. While Outdoor Temperature Reset Control has been widely used for energy savings of the secondary side system, the results show that the Outdoor Temperature Predictive Control method saves more energy. In general, the Outdoor Temperature Predictive Control method lowers the supply temperature of hot water, and it reduces standby losses and increases the overall heat transfer value of heated spaces due to more flow into the space. During actual energy consumption monitoring, the Outdoor Temperature predictive Control method saves about 6.6% of energy when compared to the Outdoor Temperature Reset Control method. Also, it is found that at partial load condition, such as during daytime, the fluctuation of hot water supply temperature with Outdoor Temperature Reset Control is more severe than that with Outdoor Temperature Predictive Control. Thus, it proves that Outdoor Temperature Predictive Control is more stable even at partial load conditions.

A study on the variation of skin temperature on the adult male at environment temperature (각 환경기온하에서의 성인남자 피부온에 관한 연구)

  • 심부자
    • Journal of the Ergonomics Society of Korea
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    • v.15 no.2
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    • pp.71-88
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    • 1996
  • For understanding skin temperature based on clothing design from a viewpoint of comfortable wearing, the skin temperature, physiological reactions(body temperature, blood pressure and pulse) and physilolgical response(thermal sensation, comfort sensation and perceptive sweaty sensation) were measured on condition tha t5 naked healthy male exposed to serveral environmental temperatures,( $20{\pm}1.0^{\circ}C$ ,$28{\pm}1.0^{\circ}C$ and $32{\pm}1.0^{\circ}C$). As the results of this testing, the regional skin temperature was varied for 90min just after expose to those the environment but was generally stabilized for the nest 90min. It was proved the difference of the regional skin temperature at low temperature environmental($20{\pm}1.0^{\circ}C$) was larger than at high temperature environmental($32{\pm}1.0^{\circ}C$) and inder serveral environmental temperature,the degree of the regional skin was not equal. Except in case of the thigh, the front of all regional skin temperature turned out higher than the back of them. According to change of environmental temperature, body temperature and pulse were altered. In the pshycological response, 'thermal sensation-comfort sensation' was felt to 'slightly warm - comfortable' at $28{\pm}1.0^{\circ}C$of the environmental temperature, and 'perceptive sweaty sensation', wneh it was said 'sweat' at only $32{\pm}1.0^{\circ}C$ of it.

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Development of Temperature Control System for Cold Storage Room Using Fuzzy Logic (퍼지논리를 이용한 저온저장고의 온도제어시스템 개발)

  • 양길모;고학균;조성인
    • Journal of Biosystems Engineering
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    • v.25 no.2
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    • pp.107-114
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    • 2000
  • Low temperature storage method is to increase the value of agricultural products by reducing quality loss and regulate consignment time by controlling respiration rates of agricultural products. Respiration rate of agricultural products depends on several factors such as temperature, moisture, gas composition and a microbe inside the storage room. Temperature is the most important factor among these, which affects respiration rate and causes low or high temperature damage. Fuzzy logic was used to control the temperature of a storage room ,which uses information of uncertain facts and mathematical model for room temperature control . Room temperature was controlled better by using fuzzy logic control method rather than on-off control method. Refrigerant flow rates and temperature deviations were measured for on-off system using TEV(temperature expansion valve) and for fuzzy system using EEV(Electrical Expansion Valve) . Temperature of the Storage room was lowered faster by using fuzzy system than on -off system. Temperature deviation was -0.6~+0.9$^{\circ}C$ for on-off system and $\pm$0.2$^{\circ}C$ for fuzzy system developed. Temperature deviation and variation of temperature deviation were used as inout parameters for fuzzy system. The most suitable input and output value were found by experiment. Cooling rate of the storage room decreased while temperature deviation increased for the sampling time of 20 sec.

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The Characteristics of Rail Temperature for Track Maintenance (궤도 관리를 위한 레일 온도의 특성)

  • 구봉근;서사범
    • Journal of the Korean Society for Railway
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    • v.3 no.1
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    • pp.19-26
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    • 2000
  • The rail temperature is important to preserve the joint gap for standard length of rail and to determine the installation temperature which has direct influence on the rail buckling and failure in welded part for continuous welded rail(CWR), Therefore, we have measured and investigated various characteristics of rail temperature for each kind of rail. As the results of this, the correlation between the atmosphere temperature and the rail temperature which is commonly used by Korean Railway should be reconsidered. Also, the daily highest '||'&'||' lowest rail temperature was occurred when each temperature is higher and when it's lower. For the light rail, the rail temperature by the sun-light increases quickly and decreases late. But the time where the highest temperature is attained is same. There are some differences between the shade and sunny place about 3.0∼4.0$\^{C}$. The temperature of rail web is almost close to the conversion rail temperature for rail expansion. The wind of 1 m/s has an influence on the rail temperature around 5$\^{C}$.

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Change of Surface Temperature in Woodceramics Made from MDF(I) -Effect of Density and Burning Temperature- (MDF로 제조된 우드세라믹의 표면온도변화(I) -밀도 및 소성온도의 영향-)

  • 오승원
    • Journal of Korea Foresty Energy
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    • v.21 no.1
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    • pp.1-6
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    • 2002
  • The following conclusions were obtained with measuring the surface temperature change of woodceramics which were made of MDF to identify usability of using them as a sub-material for heating system when installing Ondol heating floor. For this purpose, woodceramics were burned at the temperature of $650^{\circ}C$ and $800^{\circ}C$ 1. Surface temperature of woodceramics increased with the increase of density of woodceramics, but no significant difference was detected at the surface temperature when burning temperature was changed. 2. Surface temperature change under given temperature increased as time passed and it showed more increase in temperature at the burning temperature of 80$0^{\circ}C$. 3. Surface temperature change with the change in floor temperature increased u hen floor temperature increased and heating mechanism was fast with increase of measuring temperature.

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Experimental study on TDLAS temperature profile measurement using temperature binning method (TDLAS에서 temperature binning 방법을 이용한 온도 측정에 대한 실험적 연구)

  • Yoon, Sungwoon;Kim, Sewon;Shin, Myungchul;Lee, Changyeop
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.27-28
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    • 2012
  • Tunable diode laser absorption spectroscopy(TDLAS) measurement techniques for several gases densities and temperatures have been applied in industrial combustion systems. Accurate measurement of temperature profile is very important, especially in power plants and heating furnaces. So profile fitting and temperature binning methods are new issue for accurate measurement of temperature in laser gas sensing. Temperature binning method is applied in this study for the measurement of temperature profile using tube furnace with three temperature zones. In this study the temperature profiles of tube furnace is accurately measured within 5% error, and this technique is proved to be very promising in the field of temperature profile measurement.

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The Correction of Fluid Temperature for Hot-wire Anemometer (열선 유속계에 대한 유체 온도의 보정)

  • 심상학
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.6
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    • pp.92-97
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    • 1999
  • This paper reports by simple method that is quickly corrected the effects of fluid temperature for the hot wire anemometer. We are concerned with a variable output of hot wire anemometer on arbitrary fluid temperature. Hot wire by measuring boundary layer of turbulent flow has been calibrated by arbitrary temperature lower than 10$0^{\circ}C$, and velocity lower than 20m/s. As a result, we could pick up the temperature factor affected by output of hot wire anemometer from related in output of arbitrary temperature to output of room temperature. By using temperature factor on the output of hot wire anemometer, we also obtained that the relationship of velocity was of no effect by temperature of fluids. About results of calibrated hot wire, uncertainly of velocity is 2.15% at room temperature and 3.1% at arbitrary temperature.

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