• Journal of Environmental Science International
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• v.23 no.10
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• pp.1731-1743
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• 2014

The time variations in relative humidity observed at the Gangjeong (Goryeong) Reservoir in the Nakdong River over a one-year period (September 2012-August 2013) were analyzed with the Bowen ratio. The thermal vertical scale of the reservoir was also evaluated following Yamamoto's method. The study's results showed that the relative humidity at the reservoir was higher than that of the Daegu Meteorological Observatory (inland) all year round. The difference was slightly larger at nighttime (17-20 %) than at daytime (13-15 %) in all seasons except summer. The quantitative order of latent heat flux was summer, spring, autumn, and winter. This finding signifies that the thermal vertical scale of the reservoir corresponds to that of a shallow lake. The Bowen ratio was smallest at midday of the summer season. In other words, the net radiation energy was converted more as latent heat flux than sensible heat flux during a higher temperature period.

• Geophysics and Geophysical Exploration
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• v.21 no.4
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• pp.220-230
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• 2018

When thermal conductivity of rock is measured with PEDB (Portable Electronic Divided Bar) in a laboratory, it can be greatly influenced by the change of room temperature. Therefore, measuring the thermal conductivity in a thermo-hygrostat is necessary, where it can remain in its constant temperature and humidity condition. In this study, a system for thermal conductivity measurement in a thermo-hygrostat has been set up and the thermal conductivities for the 45 samples collected from GH3 and GH4 boreholes in Ulleung Island have been measured both in dry and saturated conditions. Also, the correlations between those thermal conductivities, density, and effective porosity have been discussed. As a result of correlation analysis among the thermal conductivity, density, and effective porosity, it showed higher correlation with dry samples than saturated samples. Especially, thermal conductivity ratio between saturated and dry conditions shows very high correlation ($R^2=0.90$) with effective porosity.

• Journal of Navigation and Port Research
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• v.33 no.4
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• pp.289-294
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• 2009

The living performances of crews and passengers in cabins have been less received attention, while Korea is a top leading country in ship building industry. To develop a high value added ships like 5-star cruisers, researches on the comfort and productivity in cabins should be carried out with urgent. The purpose of this study is to measure and analyze of the ship's indoor thermal conditions in spring, summer and winter, and also to compare the seasonal differences, of which conditions are supplied from and controlled by marine HVAC The temperature, humidity and air supply volume of 5 different needs of cabins on a training ship were measured through a year, which was launched at Dec. 2005 and totally 246 crews can go on board for education. The following results were obtained: (1)In the spring, the temperature in cabins was measured as $20{\sim}25^{\circ}C$ and humidity was below 30%. (2)In the summer, the temperatures was controlled at $21{\sim}27^{\circ}C$ in almost cabins and humidity was between $40{\sim}60%$ which is known as comfort conditions. (3)In the winter, temperature and humidity was maintained between $19{\sim}26^{\circ}C$, and humidity was between $10{\sim}50%$. (4)It is clear that the humidity conditions in cabins are not properly controlled at all through a year to satisfy the Comfort Standards provided by ASHRAE and/or ISO, In conclusion, humidification and dehumidification of cabins must be treated with importance for more comfort living and working environments for crews and passengers.

• Tunnel and Underground Space
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• v.6 no.4
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• pp.335-341
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• 1996

This fundamental study analyzes the relationship between rock thermal properties and psychrometric properties in underground space and has a ultimate goal to develope technologies for predicting major environmental variables. The study is divided into 2 subjects (1) developement of a basic model for predicting temperature and humidity, (2) analysis of the validity of the model through application to a local underground storage space for military supplies. The basic model is built for the network of tunnel-shaped underground spaces. The model takes into account rock thermal properties and changes in moisture content in the air due to condensation/evaporation on the rock surface. Using lumped-parameter analytical method, heat flux from or to the surrounding rock is calculated and then the psychrometric properties(air quantity, pressure, temperature, humidity) are estimated through network simulation. The model can be utilized regardless of the tunnel type. The study site is a local storage space built in rock, mainly granite gneiss and quartz-porphyry. It is a U-shaped tunnel, 593.5m long and 6x6.5m wide. Relative humidity inside has to be strictly controlled under 55% to avoid erosion of a certain types of supplies stored in 6 chambers with the capacity of 300~1.000 ton. The thermal conductivity varies between 2.734 and 2.779W/m$^{\circ}C$ and the thermal diffusivity is in the range of 1.119 and $1.152{\times}10^{-6}\;m^2/s$ the specific heat between 910 and $920\;J/kg^{\circ}C$. Relative errors of the predicted values of dry/wet temperature and relative humidity are 0.8~3.0%, 0~7.5% and 0~7.0%, respectively. Apparent errors associated with the rock surface temperature seems to be partly due to the intrinsic limitations in the infrared thermometer used in this study.

• Atmosphere
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• v.18 no.2
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• pp.137-146
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• 2008

This study examines one thermal index, perceived temperature (PT), over the Korean Peninsula during 2007 summer. Heat/cold stress has been described using air temperature and humidity for warm seasons and air temperature and wind velocity in the cold conditions, while PT is based on a heat budget model of the human body that considers air temperature, humidity, wind velocity and radiation effect regardless of climates, regions and seasons. PT is higher about $4-5^{\circ}C$ than air temperature in the summer. Humidity increases PT, while wind tends to reduces PT possibly by evaporation of water vapor. The geographical distribution of summer PT indicates that the lowest PT happened in the east central region, with the appearance of the highest PT in the inland of southern region in Korea. Although the latitudinal trend shows that PT decreases northward, inland PT is higher than that of coastal region. Compared to the heat index or the discomfort index that considers air temperature and humidity, PT represents distinctive regional characteristics of thermal comfort. The distribution of PT shows that it may be a useful thermal index for the assessment of thermal comfort or stress region in the Korean Peninsula.

• Geomechanics and Engineering
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• v.36 no.2
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• pp.99-109
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• 2024

Studying the dynamic behavior of axially moving cylindrical shells in hygro-thermal environments has important theoretical and engineering value for aircraft design. Therefore, in this paper, considering hygro-thermal effect, the nonlinear forced vibration of an axially moving cylindrical shell made of functionally graded materials (FGM) is studied. It is assumed that the material properties vary continuously along the thickness and contain pores. The Donnell thin shell theory is used to derive the motion equations of FGM cylindrical shells with hygro-thermal loads. Under the four sides clamped (CCCC) boundary conditions, the Gallekin method and multi-scale method are used for nonlinear analysis. The effects of power law index, porosity coefficient, temperature rise, moisture concentration, axial velocity, prestress, damping and external excitation amplitude on nonlinear forced vibration are explored through parametric research. It can be found that, the changes in temperature and humidity have a significant effect. Increasing in temperature and humidity will cause the resonance position to shift to the left and increase the resonance amplitude.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.421-424
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• 1996

Effects of humidity absorbing deterioration on AC dielectric breakdown characteristics of modified epoxy resin system with SN(succinonitrile) were investigated. As the forced humidity absorbing deterioration proceeded under high temperature and humidify, glass transition temperature increased. The dielectric breakdown strength increased and then decreased at deterioration cycles higher than 2. Not only, the increment of thermal stability but also, the physical detects such as Internal cracks and voids occurred during the humidity absorbing deterioration cycle were the main causes of the change in dielectric properties.

• Journal of the Korean Society of Clothing and Textiles
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• v.16 no.2
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• pp.245-254
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• 1992

The purpose of this study was to evaluate the mechanical thermal resistances and comfort properties of ski wear made with vapor-permeable water repellent (VPWR) fabrics and thermal insulation battings. Four types of experimental clothing were made with the combination of two VPWR fabrics (Hipora-$TM^{\circledR}$, Hipora-$CR^{\circledR}$) and two thermal insulation battings ($Viwarm^{\circledR},\;Airseal^{\circledR}$). Thermal resistances of ski wear were objectly evaluated by thermal manikin experiment ($21{\pm}\;2^{\circ}C,\;50{\pm}5\%$ R.H.,0.25 m/sec air velocity) and thermographic accessment ($2{\pm}2^{\circ}C,\;0\%$ R.H.,0.25 m/sec air velocity, and emissivity level : 1). Garment wear tests of ski wear included the measurement of the microclimate (inner temp. and relative humidity) of the experimental clothing by digital thermohygrometer and subject wear sensation using McNall's thermal comfort ratings. CBo values of experimental clothing 4 (Hipora-$CR^{\circledR}+Airseal^{\circledR}$) and 1 (Hipora-$TM^{\circledR}+Viwarm^{\circledR}$) were significantly higher than those of 2 (Hipora-$TM^{\circledR}+Airseal^{\circledR}$) and 3 (Hipora-$CR^{\circledR}+Viwarm^{\circledR}$). Thermal resistances in the points of breast, back, belly, and loin was significantly higher than those of upper am, fore arm, and shank of measuring points on the thermal manikin. According to the color map of the thermogram, the experimental clothing 4 indicated higher surface temperatures than the others showing more yellowish spots on the surface of clothing. Inner temperature of experimental clothing was not significantly different among the four types of ski wear, but relative humidities of experimental clothing were significantly different. Relative humidities of experimental clothing 1 and 3 showed higher than those of 2 and 4. Relative humidity of experimantal clothing was affected largely by the thermal resis- tance of thermal insulation batting materials. The subject wear sensation of experimental clothing 2 and 4 showed lower humidity than the others. Subject wear sensation was affected more by humidity sensation than by thermal sensation.

• Journal of the Korea Furniture Society
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• v.25 no.2
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• pp.148-153
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• 2014

Importance of energy consumptions has being emphasized because of problems of the energy and environment. So, recently, green wall systems have been installed to reduce building energy consumptions. The green wall systems provide several benefits; they make it possible to maintain moderate thermal comforts by greenery. Greening such a surface wall in the building by plants, the temperature of the wall can be properly controlled that purifies the air and improves the view spanning over the space. This study evaluated the effects of green wall systems on reducing room temperature quantitatively, changing of humidity, decreasing of $CO_2$. Test results were confirmed; first, the space installed by green walls showed that temperature and $CO_2$ decreased and humidity was increased. Second, two structures were compared with the solar radiation, and green wall systems controlled the temperature and humidity stably near the wall regardless of the amount solar radiation. In conclusion, the green wall systems can contribute to thermal comforts and indoor air quality in the buildings.

• Safety and Health at Work
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• v.14 no.1
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• pp.107-117
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• 2023

Background: Thermophysiological comfort in a cold environment is mainly ensured by clothing. However, the thermal performance and protective abilities of textile fabrics may be sensitive to extreme environmental conditions. This article evaluated the thermal insulation properties of three technical textile assemblies and determined the influence of environmental parameters (temperature, humidity, and wind speed) on their insulation capacity. Methods: Thermal insulation capacity and air permeability of the assemblies were determined experimentally. A sweating-guarded hotplate apparatus, commonly called the "skin model," based on International Organization for Standardization (ISO) 11092 standard and simulating the heat transfer from the body surface to the environment through clothing material, was adopted for the thermal resistance measurements. Results: It was found that the assemblies lost about 85% of their thermal insulation with increasing wind speed from 0 to 16 km/h. Under certain conditions, values approaching 1 clo have been measured. On the other hand, the results showed that temperature variation in the range (-40℃, 30℃), as well as humidity ratio changes (5 g/kg, 20 g/kg), had a limited influence on the thermal insulation of the studied assemblies. Conclusion: The present study showed that the most important variable impacting the thermal performance and protective abilities of textile fabrics is the wind speed, a parameter not taken into account by ISO 11092.