• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.576-580
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• 2009

This thesis identified basic design elements(Sustained Yield, Depth of Well, Separation Distance between wells) regarding installation of Standing Column Well, Geothermal Heat pump System by dynamic analysis.

• Journal of Energy Engineering
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• v.13 no.4
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• pp.296-300
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• 2004

Performance evaluation and economic estimation were conducted on the water to water GSHP (Ground Source Heat Pump) installed in existing building. Ground heat exchanger was a closed vertical loop type and sized to be 5 boreholes and 100m depth per borehole. Operation efficiency of the system shows that, COP increased from 3.0 to 4.2 with entering water temperature in heating operation, however, COP decreased from 5.0 to 3.7 in cooling operation. Economic estimation was analyzed by LCC (Life Cycle Cost) method and it showed that GSHP could save 68% of cost compare to the conventional oil source. Thus, despite of the large amount of initial cost, GSHP has a economic advantage to the other energy sources.

• Economic and Environmental Geology
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• v.49 no.6
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• pp.459-467
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• 2016

Due to the limited areal space for installation, borehole heat exchangers (BHEs) at depths deeper than 300 m are considered for geothermal heating and cooling in the urban area. The deep vertical closed-loop BHEs are unconventional due to the depth and the range of the typical installation depth is between 100 and 200 m in Korea. The BHE in the study consists of 50A (outer diameter 50 mm, SDR 11) PE U-tube pipe in a 150 mm diameter borehole with the depth of 300 m. In order to compensate the buoyancy caused by the low density of PE pipe ($0.94{\sim}0.96g/cm^3$) in the borehole filled with ground water, 10 weight band sets (4.6 kg/set) were attached to the bottom of U-tube. A thermal response test (TRT) and fundamental basic surveys on the thermophysical characteristics of the ground were conducted. Ground temperature measures around $15^{\circ}C$ from the surface to 100 m, and the geothermal gradient represents $1.9^{\circ}C/100m$ below 100 m. The TRT was conducted for 48 hours with 17.5 kW heat injection, 28.65 l/min at a circulation fluid flow rate indicates an average temperature difference $8.9^{\circ}C$ between inlet and outlet circulation fluid. The estimated thermophysical parameters are 3.0 W/mk of ground thermal conductivity and 0.104 mk/W of borehole thermal resistance. In the stepwise evaluation of TRT, the ground thermal conductivity was calculated at the standard deviation of 0.16 after the initial 13 hours. The sensitivity analysis on the borehole thermal resistance was also conducted with respect to the PE pipe diameter and the thermal conductivity of backfill material. The borehole thermal resistivity slightly decreased with the increase of the two parameters.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.1
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• pp.10-16
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• 2011

Performance of ground-source heat pumps (GSHPs) is mainly affected by ground heat exchangers which makes up more than 40% of construction cost. Exact construction and grout as backfill are important, because it is difficult to repair after being installed. As grout materials, bentonite grout material and cement material are used In this paper, thermal conductivity according to mix proportion of cement grout has been experimentally studied. Some variables were set to evaluate thermal conductivities according to change in cement content, unit water ratio, mass per volume of fresh mortar, and aggregate types. From the experimental analysis, high performance cement grout has been proposed.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.629-634
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• 2007

The Alternative energy has lately attracted considerable attention due to the high oil price and environment problem. In this study, field test of facility for using the geothermal energy source from water-purifying device was constructed and monitoring devices are installed to estimate the efficiency of this system. Initial installation cost can be saved efficiently by connecting a heat pump system into the existing pumping well in site of water-purifying in Cheongju. One set of monitoring results during summer was presented and analyzed.

• Journal of the Korean Solar Energy Society
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• v.32 no.1
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• pp.56-66
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• 2012

This study evaluated the economic benefits by comparing Cooling-Heating System with the existing system in the public library. The building's annual energy consumption was measured by adding the figures of the absorber chillers, the air conditioners and heaters in the building. The total amount of annual energy consumption was 143.51RT in air-conditioning and 83.66RT in heating. So, We made the capacity of geothermal heat pumps three 50RTs in order to check up this system. In order to estimate each construction and equipment cost and to evaluate economical efficiency, LCC(Life Cycle Cost) method was used and the service life of the building was sixty years. The result of analysis was that the geothermal cooling-heating system was more efficient than the existing system in public library.

• 월간 기계설비
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• no.2 s.211
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• pp.38-42
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• 2008

건설산업기본법시행령.시행규칙이 지난 해 12월 28일 개정되어 1월 1일부터 시행에 들어갔다. 이번에 개정된 시행령은 기계설비공사업 업역 확대 및 국민연금, 건강보험료 비용정산 등을 주요 내용으로 개정되었다. 대한설비건설협회는 시행령.시행규칙 개정 과정에서 업역확대를 주목표로 설정하고 신규 사업분야인 시스템에어컨 설치공사, 지열냉난방설치공사, 자동제어 분야에서 전기.통신과 업역다툼이 있었던 자동원격검침 설비공사, 지능형 제어시스템 설치공사 등을 기계설비공사업역에 추가시켰다. 이로써 지난 해 건산법 개정 시 기계설비만 겸업제한 폐지를 4년 유예시킨 성과에 버금가는 성과를 거두었다. 또한 대한설비건설협회는 국민연금, 건강보험료의 비용 정산을 민간공사에도 도입될 수 있도록 끊임없이 건의하여 이번에 개정됨으로써 회원사의 보험료 납부 부담을 줄일 수 있게 되었다. 건산법 시행령·시행규칙의 주요 개정 내용 및 설비건설업과 관련한 신.구조문 대비표는 다음과 같다.

• 월간 기계설비
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• no.8 s.205
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• pp.28-37
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• 2007

대한설비건설협회는 지난 1989년 협회 창립 이후 설비건설업계의 영역확대를 위해 분리발주를 숙원사업 중 하나로 정하고 그 동안 관계기관에 건의하는 등 끊임없는 노력을 기울여 왔다. 우리협회의 이러한 노력에 힘입어 대한주택공사를 비롯한 정보통신부, 교육인적자원부 등 주요 발주처 및 발주기관에서 분리발주를 시행하고 있다. 최근들어 기계설비공사는 단순한 기계설비에서 벗어나 쓰레기이송설비, 지열냉난방시스템 등 최첨단 기술을 접목한 다양한 시공으로 확대되고 있다. 이 과정에서 업역에 대한 확고한 규정이 없어서 설비•일반•전문건설업자간 치열한 밥그릇 싸움이 예상되고 있다. 따라서 대한설비건설협회는 이러한 신규분야가 우리 설비건설영역이 될 수 있도록 더욱 박차를 가할 계획이다. 또한 지난 5월 17일 공포된 건설산업기본법 개정(안)에는 2개 공종 이상의 소규모 단순복합공사는 전문건설업자에게 원도급을 허용하는 조항이 들어있다. 이로써 오는 2009년 7월 1일부터는 소규모 단순복합공사의 경우 전문건설업자도 전문면허를 복수로 취득하여 원도급 공사 참여 가능하게 됐으며, 분리발주와 동일한 효력을 갖는다. 본지는 앞으로 분리발주 확대를 위한 각오를 새롭게 다지기 위해 대한설비건설협회의 분리발주를 추진 과정 및 분리발주된 공사현황(10억원 이상, 2002년부터)을 살펴본다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.511-514
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• 2007

This study was performed to construct a geothermal data base about thermal conductivity of ground heat exchanger and thermal properties of grouting material which used to refill the borehole. We have acquired geothermal data sets from 39 sites over wide area of South Korea except to Jeju island. From data analysis, the range of thermal conductivity is $1.5{\sim}4.0$ W/mK. It means that thermal conductivity varies with grouting material as well as regional geology and ground water system.

• Tunnel and Underground Space
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• v.21 no.1
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• pp.11-19
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• 2011

Geothermal energy is believed to be an important source among the renewable energy sources to provide the base load electricity. Although there has been a drastic increase in the use of geothermal heat pump in Korea, there is no geothermal power plant in operation in Korea. Fortunately, the first EGS (Enhanced Geothermal System) Project in Korea has started in Dec 2010. This five year project is divided into two stages; two years for exploration and drilling of 3 km depth to confirm the minimum target temperature of 100 degrees, and another three years composed drilling 5 km doublet, hydraulic stimulation of geothermal reservoir with expected temperature of 180 degrees (40 kg/s) and construction of MW geothermal power plant in the surface. This EGS project would be a landmark effort that invited a consortium of industry, research institutes and university with expertises in the fields of geology, hydrogeology, geophysics, geomechanics and plant engineering.