• Journal of Fisheries and Marine Sciences Education
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• v.22 no.4
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• pp.604-610
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• 2010

Busan subway transportation system has been established a key role in the society last 20 years. However many people are suffering from hot and humid environment at subway station and platform due to deteriorated ventilation system as well as insufficient air conditioning system in existing stations and platforms. As a result, these systems require revitalization. There is about 5400tons of low temperature underground water is generated from subway stations every day. By using this method and air washer we are trying to lower the temperature. Air washer is commonly used for removing humidity but in this experiment it will be used as air precooling. This research offers result of experiment using air washer system to lower the temperature in large spaces like subway station. The experiment result has shown when L/G was the same, at condition which water spray temperature at $18^{\circ}C$ resulting inlet and outlet temperature difference larger. Also, in the same water spray temperature conditions, larger L/G condition showed a greater temperature difference. LCC evaluation of both system were shown that air washer system of using underground water will save 53% of the initial cost than refrigeration system, and save 75% of operating cost.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.2
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• pp.55-60
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• 2014

The present study has been conducted to develope a heating system for a green house with heat from underground air at Jeju Island. The temperature of the air deposited in the underground is $16{\sim}18^{\circ}C$ throughout the year, and it also has a large amount of moisture. Therefore, the air could not directly used for the heating of a green house. In this study, a heat pump with dehumidification function has been developed, which consisted of three evaporators, where the moisture removal occurs, accompanied by temperature drop. The dropped temperature is recovered, while passing through a series condenser. The air temperature increased from $17^{\circ}C$ to 35 with a 2.1 kg/h of moisture removal rate. The developed system moisture removal performance shows 0.91 kg/kWh.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.77-85
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• 2009

Flexible and lined segment air-tight tunnelling technology for Compressed Air Energy Storage-Gas Turbine(CAES-G/T) power generation was introduced. The distinguished characteristics of the air-tight tunnel system can be summarized by two facts. One is that the high inner pressure due to compressed air is sustained by surrounding rock mass with allowing sufficient displacement of lining segment. The other is that the air-tightness of storage tunnel was enhanced by adopting a specially designed rubber sheet. The flexible lined air-tight underground tunnel can be constructed at a comparatively shallow depth and near urban area so that the locally distributed CAES-G/T power generation can be accomplished. In addition, this air-tight tunnelling technology can be applied to a variety of energy underground storage tunnels such as Compressed Natural Gas(CNG), Liquifed Petroleum Gas(LPG), DeMethyl Ether(DME) etc.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.8
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• pp.427-431
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• 2013

Ground heat pump systems utilize the annually stable underground temperature to supply heat for space heating and cooling. The underground temperature affects not only the underground ecosystem, but also the performance of these systems. However, in spite of the widespread use of these systems, there have been few researches on the effect of the systems on underground temperature. In this research, case studies with numerical simulation have been conducted, in order to estimate the effect of ground heat pump systems on underground temperature. The simulation was coupled with the ground water-ground heat transfer model and the ground surface heat transfer model. In the result, it was found that the underground change depends on the heat transfer from the ground surface, the heat exchange rate, and the heat conductivity of soil.

• Journal of Power System Engineering
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• v.2 no.3
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• pp.27-33
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• 1998

The room temperature and air conditioning load in the underground space have been investigated numerically by the unsteady heat conduction equation. The model room has 3 m in height and 10 m in width, and it's position in the underground depth are 0.5 m to 5 m. When the room was located around surface, the room temperatures were strongly influenced by the atmosphere. But the underground depth is more than 2 m, the yearly temperature amplitude was small and the temperature phase was delayed. Up to 5 m of the depth, the cooling and heating load was decreased rapidly, but over 10 m of the depth, the air conditioning load was constant.

• Journal of the Korea Furniture Society
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• v.25 no.3
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• pp.182-187
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• 2014

Underground shopping center has become a important commercial facility due to their good accessibility to the public transport. However, underground shopping center has high risk of air contaminants emission like formaldehyde and lowered indoor air quality. In this study, formaldehyde concentration of the underground shopping center was estimated according to the renovation and characteristics of space. It was found that newly renovated underground shopping center has low formaldehyde concentration. In case of closed entrance type, the formaldehyde concentration was 320 % higher than open type. Formaldehyde concentration was varied by product type and especially, high formaldehyde concentration was measured near the stores selling nail polish and cosmetics. It is important to apply appropriate ventilation system according to characteristics of space.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.24 no.4
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• pp.429-436
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• 1995

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.250-253
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• 2007

The purpose of this research is focussed on the numerical predictions of the heat and smoke propagations for a passenger train fire in an underground subway tunnel for different air supply and extraction flowrates. The analysis is performed for one of the stations on subway line #5 in Seoul under the emergency operation mode for different air supply and extraction flowrates. Five different the air supply and extraction flowrates are considered for the numerical analyses. The numerical results show that the air supply and extraction flowrates affect the smoke control performance significantly by improving the smoke removal performance for the balanced control of air supply and smoke extraction and for the unbalanced control with lager smoke extraction than air supply.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2113-2116
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• 2010

Management of indoor air quality of underground subway station is an important issue. The air handling unit (AHU) installed in the underground subway station is the main facility determining the air quality of station. Especially for removing particulate matters, it is important to operate the appropriate air filter. However, there is no quantitative test method for existing air filter in site. It is rarely known that the collection efficiency of air filter can satisfy the designed criteria or not. In this study, we set the reference method using the mini-volume air sampler inside the AHU to evaluate the collection efficiency of different types of air filters. In addition, we applied the portable instrument based on the light-scattering method to the efficiency test. The method we applied in this study can be used in the evaluation of air filter in site.

• Journal of the Korean Solar Energy Society
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• v.34 no.5
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• pp.73-80
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• 2014

This study introduces and analyzes the geothermal energy availability in Non-active volcanic region. Jeju island in Korea is situated in non-active volcanic region. The island is composed of rock with high pore and clinker, scoria geological layer formed by volcanic activity about two million ago. Volcanic geological layers with porous characteristics have air, vapor, water and a underground structure through which air or water can move easily. For this reason, it is probable that the mechanism of energy acquisition is by convective heat transfer. For this presumption, the availability of underground air as energy source has been studied here through theoretical analysis and experimental data. The energy output of our system ranged from 2,485,076 kJ/day to 4,060,978 kJ/day monitored using variable velocity air flow controller. Our system has capability to be a reliable energy source irrespective of environmental changes. Consequently, underground air can be utilized for energy source and provide the optimal design of heating/cooling system.