• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1306-1312
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• 2011

Underground Subway station's air pollutants are introduced from the indoor or outdoor. And Radon is a major pollutant in the subway station. Radioactive substances Radon is occuring naturally in granite tunnel wall and underground water. Especially inert gas Radon that causes lung cancer in human is anywhere but 5678 S.M.R.T. tunnels deep and pass through the granite plaque have a lot of Radon. The Radon concentration is determined by the following reasons : radon content of soil and concrete, underground water, ventilation, pressure difference, building structure, temperature, etc. So Radon concentration is hard to predict. And we can't only ventilate owing to era of high oil prices. This study focuses on our efforts for the reduction of Radon concentration. And the purpose is to provide basically datas of specially managed 15 subway station's Radon concentration.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.424-425
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• 2015

In the underground cable tunnel, The transmission efficient is lowered due to the local heating region. In this reason, the cooling system is needed. For adapting the cooling system, Preceding study on the factor of increasing temperature in the underground tunnel is essential. In this paper optimal cooling system suggest.

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.222-231
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• 1994

The efficient use of solar energy for greenhouse heating is one of the most obvious applications to save the heating energy for greenhouse culture. To increase the efficiency of solar energy utilization in plastic greenhouse, underground heat exchange system was installed. Characteristics of the stored and released thermal enery in plastic greenhouse with underground heat exchange system was analyzed. The average stored and released thermal energy in this system were 1,484 $kJ/m^2$ day and 555 $kJ/m^2$ day, respectively. The average coefficient of performance of heat exchange system was found to be 2.86. Also an attempt was made to predict the air temperature in plastic greenhouse. The agreement between the results of prediction and that of measurement was relatively good.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.76-81
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• 2007

The shopping center in underground passage increased for efficient space utilization in urban area. This study describes operation characteristics of all air type and hybrid type with local ventilation and fan coil unit fixed to ceiling. In order to compare energy saving, thermal environment and installation space, etc., integrated simulator with heat production and indoor distribution system is designed and constructed. Energy saving of the hybrid system is calculated as over 30% compared to conventional all air type. And also the results showed that humidity decreased about 6%, also indoor thermal distribution is improved as temperature variation of around $1^{\circ}C$.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.87-92
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• 2022

Recently, there has been an increasing demand for electric equipment installed on the ground to be installed in an underground space. Accordingly, U-CDS (Underground-Compact Distribution Station) installed in the underground is supplied, and to improve its weak ventilation performance, an Airdam-type structure was applied and the effect was analyzed. As a result, the temperature around the transformer was reduced by up to 9.5 degrees, and the air flow increased by up to 1.17 m/s. Airdam structure can be supplied in the form of various sculptures because it is possible to design freely while maintaining its principle.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.6
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• pp.669-680
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• 2020

In Korea, fireproof performance is evaluated through a series of fire-resistance tests for important structures, and the performance standard follows the guidelines suggested by ITA. The fireproof duct slab manufactured by combining the slab and the fireproof material with a precast method is effective in that it can eliminate the construction time of the fireproof material. In this study, a series of fire resistance tests was performed on the fire test specimens under the RWS fire scenario in order to secure the fire resistance performance of the precast fireproof duct slab. As a result of the test, it was found that the fireproof performance was secured when the thickness of the fireproof material was 30 mm or more. In both fireproof materials and concrete, the rate of temperature change initially increased, then decreased, and then increased again, and the temperature at the inflection point was measured as 110℃ for all fireproof materials and concrete. It is judged that this occurs when the C-S-H (CaO-SiO₂-H₂O) generated by the hydration reaction in both the fireproof material and concrete is dehydrated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.219-235
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• 2002

This paper deals with parametric studies of the structural response of underground LNG storage tanks according to change in design conditions. In the design of underground LNG storage tank, it is requited to determine the optimal tank shape and dimension to represent a more improved structural behavior under many loading conditions and load combinations. Consequently, main factors which affect to the structural response of LNG storage tanks from planning and design up to maintenance, are investigated, and the differences in structural behavior due to those factors are analyzed. On the basis of the obtained results item parametric studies, a guideline for a more reasonable design is introduced.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.673-686
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• 2022

Recently, as the importance of eco-friendly energy has increased hydrogen gas is in the spotlight as future energy. Due to its special properties, hydrogen gas is more difficult to detect requiring more precise sensing technology. The primary objective of this study is to design a concept of an underground hydrogen pipeline monitoring system. For this, the following research works are conducted sequentially; 1)selection of core technology for conceptual design, 2)state-of-the-art review, 3)design of a concept of the system. As a result, DAS(Distributed Acoustic Sensing), and DTS(Distributed Temperature Sensing) are selected as each core technology. Furthermore, a conceptual design of an underground hydrogen pipeline monitoring system is deducted. It is expected that the impact on the eco-friendly energy industry will be enormous due to the increasing interest in using hydrogen energy.

• Journal of the Korean GEO-environmental Society
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• v.18 no.9
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• pp.5-9
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• 2017

On the flow of groundwater, the effect of consecutive column-wall in underground as a hydraulic barrier could be identified by conventional geotechnical methods ((1)visualiy identification of wall mass after underground excavating, (2)uniaxial compressive strength test for core of wall mass in underground, (3)in-situ permeability test in the hole after coring wall mass). However, for the cut off the leakage or infiltration of very high concentrated leachate from the waste landfill or the contaminated groundwater, the waterproof effect of consecutive column-wall in underground should be verified more objectively, by in-situ measuring of pH, temperature and salinity. and by evaluating of their consistency and similarity throughout analyzing the characteristics of basic components and their profiles through the series of chemical experiments. Furthermore, its waterproof effect could be verified additionally throughout deciding the similarity more simply by comparing the general distribution patterns including the difference of high and low peaks from the chromatograms using GC-MS for surrounding groundwater.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.3
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• pp.259-267
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• 2005

This paper analyzed characteristic of temperature change as well as bottom of tunnel with thermometer according to tunnel length and region during one year. And it measured temperature distribution near tunnel portal. In the paper it was known that tunnel entrance and exit have different characteristic temperature distribution in accordiance with bottom of tunnel per tunnel length. Temperature of tunnel changed from tunnel exit to fifty meter and distribution of tunnel temperature was established uniform regardless of tunnel length. But temperature distribution of tunnel changed in tunnel entrance differ from tunnel exit in the location of one hundred twenty five meter and one hundred fifty meter. Cold air inflowed from tunnel entrance have influenced with the location of one hundred twenty five meter and one hundred fifty meter.