• Membrane and Water Treatment
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• 제2권3호
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• pp.147-158
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• 2011

Membrane distillation process was used for desalination of hot (333 K) geothermal water, which was applied in the plant producing heating water. The investigated water contained 120 g salts/$dm^3$, mainly NaCl. The mineral composition was studied using an ion chromatography method. The obtained rejection of solutes was closed to 100%, but the small amounts of $NH_3$ also diffused through the membrane together with water vapour. However, the composition of obtained distillate allowed to use it as a makeup water in the heating water system. The geothermal water under study was concentrated from 120 to 286 g NaCl/$dm^3$. This increase in the solution concentration caused the permeate flux decline by a 10-20%. The geothermal water contained sulphates, which was subjected to two-fold concentration to achieve the concentration 2.4-2.6 g $SO{_4}{^{2-}}/dm^3$ and the sulphates then crystallized in the form of calcium sulphate. As a results, an intensive membranes scaling and the permeate flux decline was observed. The XRD analysis indicated that beside the gypsum also the NaCl crystallites were deposited on the membrane surfaces. The fresh geothermal water dissolved the mixed $CaSO_4$ and NaCl deposit from the membrane surface. This property can be utilized for self-cleaning of MD modules. Using a batch feeding of MD installation, the concentration of geothermal water was carried out over 800 h, without significant performance losses.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1447-1454
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• 2009

Currently, geothermal heat pump systems are being installed in new official and commercial building, welfare facilities, and school but there are a few cases for the housing heat sink in Korea. The reason is that there are no progressive taxes for the household electrical use, no actual output for the application of geothermal technology, high initial investment. For the overall use in multi family apartment such as the Green Home etc, technology development and building of the relevant research team need to be done through preliminary study. Core subjects for overall use include cooling heating load estimation for the multi family apartment, economical efficiency of the geothermal cooling and heating system, design and construction technology of the geothermal cooling and heating system for the multi family apartment, commercialization plan, and state of the art analysis. Selection of the detailed subjects with respect to core subject, driving schedule and commercialization plan, driving system, presentation of the utilization plan.

• 한국지열·수열에너지학회논문집
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• 제4권2호
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• pp.9-14
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• 2008

400RT geothermal system which is consist with vertical-typed 112 geothermal heat exchangers is measured and evaluated in spring, 21st${\sim}$24th May 2008. As the results, the average temperature difference between inlet and outlet of geothermal pipes is $1{\sim}2^{\circ}C$ and that of cool water supply is $2{\sim}6^{\circ}C$, when being normally operated. Despite temperature fluctuations by cooling loads, the average temperature difference between main pipes of inlet and outlet of geothermal heat exchangers is measured as $3^{\circ}C$. The geothermal system COPs are calcluated as 2.92${\sim}$3.92 in every 12 hours.

• 설비공학논문집
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• 제30권4호
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• pp.186-194
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• 2018

A ground-source heat pump system (GSHP) is more energy efficient than other heat-source systems because it uses annual constant underground and water temperatures. Especially, two-well geothermal systems using groundwater as the heat source can achieve higher performance than closed-loop geothermal systems. However, performance of two-well geothermal systems is decreased by occurring overflow according to scale during long-term operations. Therefore, this study presents a two-well pairing geothermal system that controls the groundwater level of a diffusion well. In addition, a two-well pairing geothermal system and an SCW geothermal system were installed, and a comparative analysis of cooling performance depending on system operation under the same load conditions was conducted. The result was that the average heat pump coefficient of performance (COP) of the two-well pairing system was 6.5, and the entire system COP was 4.3.

• 신재생에너지
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• 제8권3호
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• pp.38-46
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• 2012

Enhanced Geothermal System (EGS) among geothermal system types enables to produce sustainable energy even in non-volcanic region while conventional geothermal energy has been restricted to obtain only from hot and permeable formation such as in volcanic regions. Successful EGS project in terms of economy, however, can be expected only when the project is managed effectively considering most of influencing factors (e.g., tangible and intangible resources, cost, time, risks, etc.). In particular, well construction is of the utmost importance in geothermal project as it dominantly influences on time and cost in the whole project. Therefore, when it comes to viable geothermal project without abundant experience, managing drilling economically and efficiently is inevitable. In this study, a project management system for well construction in geothermal project based on project control system including work breakdown structure and cost account was developed to predict and assess the performance of drilling and to visualize the progress.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.441-444
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• 2007

International Geothermal Association (IGA) and Geothermal Implementing Agreement (GIA) under Committee on Energy Research & Technology (CERT) of International Energy Agency (IEA) are the two major international organizations leading geothermal research, development and deployment (RD&D). IGA has been established in 1988 by geothermal societies in Europe and America and presently consists of 23 affiliated societies. Current number of members of IGA reaches 2,000 from 65 countries and its most important activity may be to organize the World Geothermal Congress (WGC) every five years. IEA-GIA has been established in 1993 and its executive committee (ExCo) consists of 11 countries, 1 organization (EC) and 3 sponsor companies. Korea became a member of ExCo on September 2005 through Korea Institute of Geoscience & Mineral Resources (KIGAM) as representative. KIGAM is also actively participating in Direct Use Annex through a task leader of several tasks.

• 한국지열·수열에너지학회논문집
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• 제4권2호
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• pp.1-7
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• 2008

GSHP(Ground Source Heat Pump) has been extensively disseminated due to the recent increasing demand over new and renewable energy. However, the system reliability has been key issues and barriers to insure a better system performance as designed originally in ISO (international standard organization) standard. This paper introduces a systematic method to verify its intended design target so called as ISO performance data based commissioning technology for a water to air GSHP system. The commissioning technology starts from are to the international standard ISO performance data of a GSHP model and to compare its installed operation data and to calibrate and tune to the target optimum operation parameters. Results indicated that cooling capacity could be raised up to 76.6% from 46.6% from this proposed commissioning technology.

• 한국태양에너지학회 논문집
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• 제27권2호
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• pp.11-17
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• 2007

This study evaluates the seasonal performances of the horizontal-type geothermal heat exchanger(HGHEX) installed into the foundation slabs of the complex building located at Seoul. The geothermal system is consisted with totally 31,860m long HGHEX, 16 GSHPs (Ground-source Heat Pump) and 8 circulation pumps. This system supplies cooling and heating to the lobby(F1) and the common spaces(BF1). The average heat exchange temperature differences are $2.7^{\circ}C\;and\;2.5^{\circ}C$ in the summer, $1.5^{\circ}C\;and\;0.5^{\circ}C$ in the winter for the F1 and BF1 respectively. From these results, approximately 400Gcal and 180Gcal of geothermal energy are assumed to have been used during the summer and winter seasons respectively. As a conclusion, the geothermal system is reviewed as a effective utility for heating and cooling at the point of seasonal performances.

• 한국지열·수열에너지학회논문집
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• 제3권1호
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• pp.11-16
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• 2007

The purpose of this study is to use the CFD(Computational Fluid Dynamics) method for the ground source heat pump(GSHP) system with vertical U-tube ground heat exchangers. In order to predict LWT(leaving water temperature) in the length of time, This simulation is used by utilizing FLUENT which is commercial CFD code. It was performed by based on four boreholes in the field. Comparing with the results of CFD and field measurement for LWT, the results of CFD was presented very good agreement with 1.0% average difference.

• 한국지열·수열에너지학회논문집
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• 제10권2호
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• pp.19-23
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• 2014

In the capital of Mongolia where the air quality is getting worse due to the coal consumption used for electricity generation and district heating, the application of geothermal systems in the housing sector is recently designed for high class resort. In this study, the case of applying a geothermal system in a house in Mongolia is examined. The effects of passive house design on the needed heat pump capacity, as well as the annual energy consumption are analyzed. Moreover, as the initial costs, except labor fee, are assumed similar to Korea, cost analysis for several cases is examined, too. From the results, if a house is designed according to passive house standard instead of ASHRAE standard, the heat pump capacity can be expected to be reduced from 16 to 5~6 RT. Furthermore, although the initial cost of architectural cost might increased by 29 M\, the total initial cost is reduced by 14 M\, while the annual energy consumption is reduced by 14%. This is mainly driven by the fact that the geothermal system which serves as the main system to cover the building needs, with a high initial cost for fulfilling the peak requirements.