• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.1
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• pp.44-51
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• 2009

In order to determine air temperature difference by canopy layer in the forest, air temperatures were observed at Seolleung Park, Gahngnam-ku, Seoul. from November 9, 2007 to November 8, 2008 by 10 minute interval. The data were analyzed in terms of diurnal variation based on annual and monthly temperature difference. Using calm, less cloudy and no rainy weather data, average air temperature difference between forest and grass was observed as $0.8^{\circ}C$. The maximum air temperature difference was observed at 22:10, 23:20, 23:30 and 23:40 by $2.13^{\circ}C$ and the minimum one observed at 13:00 by $-0.84^{\circ}C$ in diurnal variation. The maximum temperature difference occurred at 19 : 50 on September by $3.67^{\circ}C$, Overall the air temperature in the forest was higher than that of grass at night and lower in midday.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.5
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• pp.345-350
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• 2014

This study was conducted to investigate the changes in daily surface temperature of red pepper leaf compared to air and soil surface temperature. The maximum, minimum and average daily temperatures of red pepper leaf were 27.80, 11.40 and $19.01^{\circ}C$, respectively, which were lower by 0.10, 7.60 and $3.86^{\circ}C$ than air temperature, respectively, and lower by 15.00, 0.0 and $4.38^{\circ}C$ than soil surface temperature, respectively. Mean deviations of the difference between measured and estimated temperature by the E&E Model (Eom & Eom, 2013) for the air and surface temperature of red pepper leaf and soil were 0.64, 1.82 and $4.77^{\circ}C$, respectively. The relationships between measured and estimated scaled factor of the air and surface temperature of red pepper leaf and soil were very close to the 1:1 line. Difference between air and surface temperature of red pepper leaf showed a linear decreasing function with the surface temperature of red pepper leaf. Difference between soil surface temperature and air and surface temperature of red pepper leaf linearly increased with the soil surface temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.419-428
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• 2010

This paper presents the optimization process of liquid desiccant cooling system using LiCl aqueous solution as a working fluid. Operating conditions(mass flow rate, conditioner outlet concentration, difference concentration) and design factors for heat exchangers(difference temperature of the district heating water, leaving temperature difference of the conditioner, leaving temperature difference of the regenerator, air temperature difference of the conditioner, air temperature difference of the regenerator) were optimized by response surface method. As a result, we obtained the 7.297 kW of cooling capacity and 0.788 of COP at optimized condition. Effect of difference temperature of hot water on system performances was also examined. As difference temperature of the district heating water increases, the cooling capacity increases and COP decreases.

• 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.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.3
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• pp.303-313
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• 2005

In this study, meteorological characteristics concerning the occurrence of fog are analyzed using 4-years $(2000\~2003)$ data at Chuncheon and the probability of prediction is investigated. From the analysis of meteorological characteristics, the fog at Chuncheon occurred before sunrise time and disappeared after that time and lasted for $2\~4$ hours. When fog occurred, on the whole, wind direction was blew the northerly and wind speed was below 2.1m/s. Especially, about $42\%$ of foggy day fell on the calm $(0\~0.2\;ms^{-1})$ conditions. The difference between air temperature and dew point temperature near the surface were mainly less than $2^{\circ}C$. For the lack of water surface temperature, the water surface temperature was calculated by using Water Quality River Reservoir System (WQRRS) and then it was used as the surface boundary condition of MM5. The numerical experiment was carried out for 2 days from 1300 LST on 14 October 2003 to 1300 LST on 16 October 2003 and fog was simulated at dawn on 15 and 16 October 2003. Simulated air temperature and dew point temperature indicate the similar tendency to observation and the simulated difference between air temperature and dew point temperature has also the similar tendency within $2^{\circ}C$. Thus, the occurrence of fog is well simulated in the terms of the difference between air temperature and dew point temperature. Horizontal distribution of the difference between air temperature and dew point temperature from the numerical experiment indicates occurrence, dissipation and lasting time of fog at Chuncheon. In Chuncheon, there is close correlation between the frequency of fog day and outflow from Soyang reservoir and high frequency of occurrence due to the difference between air and cold outlet water temperature.

• The Research Journal of the Costume Culture
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• v.10 no.6
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• pp.793-801
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• 2002

The effects of ambient air temperature on the clothing ventilation were investigated numerically by a finite difference method. Numerical analysis using a 2-dimensional model comprising the air space between the skin and the clothing was conducted under the assumption that the clothing ventilation occurred only through the openings not through the fabric. The larger the temperature difference between the skin and the surroundings, the more apparent the thermal boundary layer As the ambient air temperature decreased, the air flow and the rate of the return of oxygen concentration to the atmosphere level in the clothing increased. Convection was dominant under low ambient air temperature, whereas conduction was dominant under high ambient air temperature. The ventilation rate was faster in the clothing microenvironment of the body part than that of the arm part.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.2
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• pp.195-206
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• 2002

The conjugate heat transfer from the simulated module in a horizontal channel with the variation of inlet air temperature is experimentally investigated. The aim of this study is to estimate temperature difference between a module and inlet air. This study is performed with the variation of parameters that are inlet air temperature(Ti=25~$55^{\circ}C), thermal resistance( $R_c$=0.05, 4.11, 158 K/W), inlet air velocity(Vi=0.1~1.5m/s), and input power(Q=3, 7 W). The results show that the effect of inlet air temperature is little, at the case of using conductive board. And input power was most effective parameter on the temperature difference between module and Inlet air.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.11-18
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• 2014

To investigate the influence of surrounding environment on the plant temperature and examine the effect of plant temperature control by fogging and airflow, plant temperature of tomato, inside and outside air temperature and relative humidity, solar radiation and wind speed were measured and analyzed under various experimental conditions in plastic greenhouse with two-fluid fogging systems and air circulation fans. According to the analysis of plant temperature and the change of inside and outside air temperature in each condition, inside air temperature and plant temperature were significantly higher than outside air temperature in the control and shading condition. However, in the fogging condition, inside air temperature was lower or slightly higher than outside air temperature. It showed that plant temperature could be kept with the temperature similar to or lower than inside air temperature in fogging and airflow condition. To derive the relationship between surrounding environmental factor and plant temperature, we did multiple regression analysis. The optimum regression equation for the temperature difference between plant and air included solar radiation, wind speed and vapor pressure deficit and RMS error was $0.8^{\circ}C$. To investigate whether the fogging and airflow contribute to reduce high temperature stress of plant, photosynthetic rate of tomato leaf was measured under the experimental conditions. Photosynthetic rate was the highest when using both fogging and airflow, and then fogging, airflow and lastly the control. So, we could assume that fogging and airflow can make better effect of plant temperature control to reduce high temperature stress of plant which can increase photosynthetic rate. It showed that the temperature difference between plant and air was highly affected by surrounding environment. Also, we could estimate plant temperature by measuring the surrounding environment, and use it for environment control to reduce the high temperature stress of plant. In addition, by using fogging and airflow, we can decrease temperature difference between plant and air, increase photosynthetic rate, and make proper environment for plants. We could conclude that both fogging and airflow are effective to reduce the high temperature stress of plant.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.2
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• pp.137-145
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• 1992

coefficient precisely, experiments were carried out in three categories which contain the regime of (1) constant wire temperature (2) constant fluid temperature (3) constant temperature difference between wire and fluid. Measurements were made with electrically heated circular tungsten wire placed normal to air stream at the exit of jet. Heat transfer coefficient was increased with wire temperature increasing and decreased by fluid temperaure increasing and was not changed with varying both temperature if their difference were kept constant.