• Korea Journal of Geothermal Energy
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• v.7 no.1
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• pp.30-33
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• 2011

• Korea Journal of Geothermal Energy
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• v.9 no.3
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• pp.67-73
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• 2013

• Korea Journal of Geothermal Energy
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• v.6 no.4
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• pp.5-12
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• 2010

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.461-471
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• 2016

Numerical modules based on a conventional thermo-hydrological numerical model, TOUGH2, are developed to provide a numerical modeling technique for a standing column well (SCW). Cooling and heating operations for two different types of SCW are then simulated using these modules. Modeling showed these operations to be significantly influenced by heat exchange and fluid mixing between the SCW and the adjacent geologic formation and groundwater. The results also reveal that heat exchange between the oppositely flowing outflow and inflow in the PVC or PE pipe and the SCW borehole is an important factor. Overall, the numerical modeling technique developed here can reasonably simulate fluid flow and heat transport phenomena in the complex internal structures of a SCW. The proposed technique can be used practically for the quantitative analysis of heat exchange in a SCW at the design, construction, and operation stages.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.3
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• pp.14-20
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• 2019

In this study, the technologies and regulations for distributing standing column well(SCW) ground source heat pump systems to the residential cluster homes were investigated. They have only been installed in the public or commercial building having different load pattern and site structure compared with the residential cluster homes. Some of SCWs for the residential cluster homes should be installed under the basement due to a lack of site area. There are pressure differences between the SCWs installed under ground surface and basement. It is needed to develop the technology or devices to prevent overflow caused by pressure difference among the SCWs. In addition, heat balance algorithm between SCWs should be adopted to maximize the system efficiency. A heat pump having heating, cooling, hot water, heating-hot water, and cooling-hot water modes should be developed for adopting an individual air-conditioning system to the residential cluster homes.

• Journal of the Korean Geotechnical Society
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• v.26 no.2
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• pp.45-54
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• 2010

The SCW numerical model described in the companion paper was used to carry out a comprehensive parametric study to evaluate the performance of the SCW. The five ground related parameters, which are porosity, hydraulic conductivity, thermal conductivity, specific heat, geothermal gradient, and five SCW design parameters, which are pumping rate, well depth, well diameter, dip tube diameter, bleeding rate, were used in the study. Two types of numerical simulations were performed. The first type was used to perform short-term (24-hour) simulation, while the second type 14 day simulation. The study results indicate that the parameters that have important influence on the performance of SCW were hydraulic conductivity, thermal conductivity, geothermal gradient, pumping rate, and bleeding rate. The thermal conductivity had the most important influence on the performance of the SCW. With the increase in the geothermal gradient, the performance increased in the heat mode, but decreased in the cooling mode. The hydraulic conductivity influenced the performance when the value was larger than $10^{-4}m/s$. The depth of the well increased the performance, but at the cost of increased cost of boring. The bleeding had an important influence on SCW, greatly enhancing the performance at a limited increased cost of operation. Overall, this study showed that various factors had a cumulative influence on the performance of the SCW, and a numerical simulation can be used to accurately predict the performance of the SCW.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1347-1352
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• 2008

The SCW ground heat pump system releases ground energy from the ground water of ground heat exchanger. In other word, ground water is used to heating through releases ground energy which oneself has. But the thermal efficiency of system is going to down because repetitive process of ground water will lost ground energy in standing column well system and if heating load is continually increase, energy of ground water may be frozen or there are no benefits to use ground energy as it owes just little energy. To solve these problems, there are need to exchange water to the ground heat exchanger then the way will be used to maintain Efficiency continually as the way of to be supplied with fresh ground water into ground heat exchanger. However, this type causes waste of ground water. Therefore it is essential to discharge water to outside timely on a heat exchanger. Therefor through a study, find out the best time to discharge water to outside and exchange water to ground heat exchanger, and propose to the DB of design of the ground heat exchanger.

• 한국해양학회지
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• v.12 no.1
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• pp.13-32
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• 1977

In order to determine the distributional ecology, and to investigate factors influencing these features, the diatom communities in plankton at depths of one, twenty-five, fifty, and seventy five meters in the area were studied and measured over a fifteen month of period. Measurements of environmental factors including temperature and salinity and algal nutrients such as phosphate, silicate, nitrate, and ammonia were also made at the same depths and locations. The results indicate that the size of diatom communities and the species population changes were heavily dependent upon to season and location parameters as well as nutrient concentrations and hydrographic factors. Major factors influencing population distributions varied with principal species responsible for dominant species and species sucession. Two distinct distributional patterns in total diatom crop were observed in the study area. Maximum standing crop observed during spring and/or summer were related to the concentration of nutrients available at the onset of the spring bloom on a large scale. On a small scale, however, the distributions of total diatom standing crops were significantly correlated with both season/location factors and with hydrographic parameters as well. Vertical stratification of diatoms was observed only in the presence of the thermocline in the water column. Within the study area there was some seasonal consistancy in the composition of the species groups. However, some species association in these environments may vary with the change of season.

• The Journal of Korean Physical Therapy
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• v.11 no.2
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• pp.93-102
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• 1999

Alignment of the hip joint and pelvis affects it's weight-bearing capabilities as well as the motion available at the joints. The normal hip joint is well designed to withstand the forces that act through and around it, assisted by the trabecular systems, cartilagious, muscles, and ligaments. Alterations in the direction or magnitude of forces action around the injury and degenerative changes. The integration of motion of the pelvis with motion of the vertebral column not only increases the ROM available to the total column but also reduces the amount of flexibility required of the lumbar lesion. In any instance in which there is normal or abnormal pelvic motion during weight hearing and the head must remain upright, compensatory motions of the lumber spine will occur if available. The motions that occur at the hip, pelvis, and lumbar spine during forward trunk bending with the motions that occur during anterior and posterior tilting of the pelvis in the erect standing postion.

• Membrane and Water Treatment
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• v.11 no.4
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• pp.247-255
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• 2020

Sand filter is a key unit process for particle removal in water purification treatments. Its long-standing use is due to on-site customized retrofit. Proper selection of filter media is one of the retrofit approaches to improve filter performance. This study described a series of controlled laboratory column tests and examined the effects of media property on filtration and backwash. When sand media of 0.51 mm in effective size was replaced by sand of 0.60 mm, the filter run increased up to 5 times in the given bed depth. The change of media property required an increase of backwash rate by 0.05 m/min to satisfy the requirement of bed expansion, more than 20%. When the anthracite was changed with lower effective size and uniformity coefficient, correlation with sand in the filter bed could be satisfied within the permissible error between media and bulk characteristics. Besides, this selection resulted in a well-stratified configuration of media layers after bed expansion. The column study showed that the correlation of property between the dual media had a significant effect on the filter productivity and backwash interval.