• Journal of the Korean Solar Energy Society
• /
• v.26 no.4
• /
• pp.83-91
• /
• 2006

As a demand for sustainable development rises, the preference for earth house (earth construction) increases gradually. However, there are few data for predicting and evaluating the thermal environment and indoor air quality of earth house. Thus, this study aims to measure thermal properties(thermal conductivity, density and specific heat) and pollutants emission intensities(formaldehyde and volatile organic compounds) of current main earth construction materials and make a comparison between earth and cement construction materials. As results, quantitative thermal properties and pollutants emission intensities of current main earth construction materials are shown.

• KIEAE Journal
• /
• v.10 no.2
• /
• pp.3-8
• /
• 2010

Many countermeasures are presented to make excessive earth circumstance pollution better in the earth. A lot of researches are in progress to lessen $CO_2$ among the industries exhausting it. The industries manufacturing cement are making many countermeasures. Many concernments on ECO-friendly materials, rather than cement, are increased, and researches are in progress to develop them. Lime, material mostly used before Portland cement appeared, attracts the Occident as well as the Orient. In the Occident, lime mortar was used in common, for maintaining and repairing cultural properties, too. This study is aimed at offering basic materials for the modern use of lime, ECO-friendly material. This study measured the change of intensity and weight with lime, sand, and earth, basic materials of Samhoimool. As a result, at the beginning, hydrated lime displayed its density late, but as time was gone, density was promoted continuously. In addition, density was promoted, when it was given heat at the beginning. If heat-generation reaction of quicklime and water was used, density was promoted at the beginning, but liquidity showed a drop.

• Journal of Soil and Groundwater Environment
• /
• v.20 no.4
• /
• pp.41-50
• /
• 2015

Open-loop groundwater heat pump (GWHP) system generally has benefits such as a higher coefficient of performance (COP), lower initial cost, and flexible system size. The hydrogeological conditions in Korea have the potential to facilitate the use of the GWHP system because a large number of monitoring wells show stable groundwater temperatures, shallow water levels, and high well yields. However, few studies have been performed in Korea regarding the GWHP system and the most studies among them dealt with Standing Column Well (SCW). Because the properties of the aquifer have an influence on designing open-loop systems, it is necessary to perform studies on various hydrogeological settings. In this study, the hydrogeological and thermal properties were estimated through various tests in the riverside alluvial layer where a GWHP system was installed. Under different groundwater flow velocities and pumping and injection rates, a sensitivity analysis was performed to evaluate the effect of such properties on the design of open-loop systems. The results showed that hydraulic conductivity and thermal dispersivity of the aquifer are the most sensitive parameters in terms of performance and environmental aspects, and sensitivities of the properties depend on conditions.

• Korean Journal of Ecology and Environment
• /
• v.36 no.3 s.104
• /
• pp.277-285
• /
• 2003

Temperature profiles were observed to understand seasonal variation of thermal structures in the Juam reservoir from March 2000 to May 2001. Heat flux which affects thermal structures was calculated by observed water temperature and meteorological data. Temperature became homogeneous vertically by convection due to the surface cooling in winter. Maximum heat loss through the surface (109.45W/$m^2$) occurred in December. There was a horizontal gradient of water temperature in winter. The temperature was $3^{\circ}C$ at upstream and $5^{\circ}C$ near the dam. The surface temperature increased by the increase of solar radiation in spring and summer. Maximum heat gained through the surface was 101.95 W/$m^2$ in July. Maximum surface temperature was $29^{\circ}C$ in August, whereas the bottom water was $7^{\circ}C.$ Surface mixed layer became thicker and its temperature decreased by surface heat loss in fall and winter.

• Journal of Environmental Science International
• /
• v.16 no.1
• /
• pp.65-71
• /
• 2007

This study aims to estimate a urban heat island potential distribution based on the land-use types using Landsat TM(1100 LST August 2004) and AWS data in Daegu. The heat island potential is defined as a difference between surface temperature and air-temperature at each place. The study area was selected as about $900km^2$ square including Daegu metropolitan area. Land-use data obtained by dividing all of Daegu metropolitan area in- to 1-km-square three types of maps were prepared in the 1960s, 1970s and 2000s respectively. Land-use types were classified into 5 categories. Forest and farm lands have been reduced at a wide range during 40 years. Most of those changed into urban area. The heat island potential distribution presented a striking contrasts according to land-use types. For example, the heat island potential of urban area was higher than $10^{\circ}C$ in comparison to those of water or paddy rice areas.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.1
• /
• pp.121-129
• /
• 2008

study proposes a new key-segment closing method using thermal effect as a substitute to the process of set-back and reset-back for the FCM construction of a partially earth-anchored cable-stayed bridge. The proposed method is to artificially heat up the inside of girders located in the main span before closing the key-segment in a cantilever state. Then, the heat is removed after finishing the closure in a continuous bridge state. Using the changes in boundary conditions and structural systems, the proposed method can generate new member forces that reflect the advantage of the partially earth-anchored cable system. From the construction sequence analysis, it is found that the proposed method increases the efficiency of a partially earth-anchored cable-stayed bridge by reducing the compressive axial forces on the girders.

• Atmosphere
• /
• v.17 no.4
• /
• pp.421-433
• /
• 2007

We have investigated the seasonal characteristics of surface turbulent fluxes observed at Ieodo Ocean Research Station from 2005 to 2006. Both 10Hz and 30 minutes flux data are quality controled, and tilt correction is performed in 10Hz data before quality control. The turbulent fluxes of open sea shows clear seasonal variations, though diurnal variations are barely shown. The seasonal ratio of stable and unstable conditions are closely related to the temperature difference between sea surface and air. In stable and semi-stable condition, latent and sensible heat fluxes have very small values without any relationship with wind speed. Though friction velocity shows slightly increasing trend with wind speed, it has many outliers. In unstable condition, turbulent fluxes increased with wind speed. Especially, latent heat flux increased rapidly during DJF. The latent heat flux at high wind speeds is more scatter.

• Journal of the Korean Solar Energy Society
• /
• v.36 no.3
• /
• pp.87-94
• /
• 2016

Earth tube system can be installed in many ways. However, performance data on earth tube system is still insufficient. Therefore, in this study seven design parameters of earth tube systems were chosen such as underground earth tube length, depth, tube thermal conductivity, thickness, radius, soil conditions, and fan type. And the change effects in the values of the seven parameters on earth tube exit temperatures and heat transfer rate were examined through Energyplus simulations.

• Journal of Wetlands Research
• /
• v.21 no.4
• /
• pp.344-353
• /
• 2019

Heat waves are a global phenomenon that exacerbate the risks associated with heat exposure and cause fatal human injury. The subject of this study was tropical night, one of the forms of heat waves. In this study, we investigated how the trend of tropical night in Korea is changing. From 1973 to 2018, we analyzed the temporal changes of the six tropical nights using daily minimum air temperature at 60 ASOS stations in Korea Meteorological Administration. From these analyzes, 10 sites were selected as attention sites for tropical nights: Incheon, Gangneung, Cheongju, Jeonju, Gwangju, Jangheung, Yeosu, Geoje, Gumi, Yeongdeok. The severe sites for tropical nights were identified as 14 sites including Hongcheon, Yangpyeong, Suwon, Wonju, Boryeong, Daejeon, Buan, Jeongeup, Mokpo, Geochang, Miryang, Pohang, Jeju, and Seogwipo. At the severe sites identified, special tropical night measures will need to be established.

• Journal of Environmental Science International
• /
• v.29 no.12
• /
• pp.1153-1170
• /
• 2020

With global warming and the rapid increase in urbanization accompanied by a concentration of population, the urban heat island effects (UHI) have become an important environmental issue. In this study, rooftop greening and permeable asphalt pavement were selected as measures to reduce urban heat island and applied to a simple virtual urban environment to simulate temperature change using ENVI-met. A total of five measures were tested by dividing the partial and whole area application of each measure. The results showed that the temperature range of the base experiment is 33.11-37.11 ℃, with the UTCI comfort level described as strong heat and very strong heat stress. A case applied permeable asphalt has a greater temperature difference than a rooftop greening case, the larger the area where each condition was applied, the greater the temperature change was.