• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.505-510
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• 2007

Greenhouses should be heated during nights and co Id days in order to fit growth conditions in greenhouses. Ground source heat pump(GSHP) or geothermal heat pump system(GHPs) is recognized to be outstanding heating and cooling system. Horizontal GSHP system is typically less expensive than vertical GSHP system but requires wide ground area to bury ground heat exchanger (GHE). In this study, a horizontal GSHP system with thermal storage tank was installed in greenhouse and investigated as performance characteristics. In the daytime, heating load of greenhouse is very small or needless because solar radiation increases inner air temperature. The results of study showed that the heating coefficient of performance of the heat pump($COP_h$) was 2.9 and the overall heating coefficient of performance of the system($COP_{sys}$) was 2.4. Heating energy cost was saved 76% using the horizontal GSHP system with thermal storage tank.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.447-452
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• 2007

Greenhouses should be heated during nights and cold days in order to fit growth conditions in greenhouses. Ground source heat pump(GSHP) or geothermal heat pump system(GHPs) is recognized to be outstanding heating and cooling system. Horizontal GSHP system is typically less expensive than vertical GSHP system but requires wide ground area to bury ground heat exchanger(GHE). In this study, a horizontal GSHP system with thermal storage tank was installed in greenhouse and investigated as performance characteristics. In the daytime, heating load of greenhouse is very small or needless because solar radiation increases inner air temperature. The results of study showed that the heating coefficient of performance of the heat pump ($COP_h$) was 2.9 and the overall heating coefficient of performance of the system($COP_{sys}$) was 2.4. Heating energy cost was saved 76% using the horizontal GSHP system with thermal storage tank.

• 한국태양에너지학회 논문집
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• 제28권3호
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• pp.7-14
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• 2008

400RT geothermal system which is the biggest capacity among on-operations at present in Korea is measured and evaluated on 23rd${\sim}$26th Jan. 2008 during those days building is not allowed owners and/or tenants to move in. The geothermal system is consist with vertical-typed 112 geothermal heat exchangers which are installed circle-like 1 row with 4m interval, and has 16 units of 25USRT geothermal-source heat pump(GSHP)s. And each 5 units of circulation pump are running for geothermal heat exchangers and hot water supplies. The followings are the results. The temperatures at G.L. -70m of 2 boreholes are varied quite similarly. The average temperature difference between inlet and outlet of geothermal pipes is $4.1^{\circ}C$, and that of hot water supply is $3.2^{\circ}C$, of Zone 3's each 4 GSHPs when being operated. Despite temperature fluctuations by heating loads, the average temperature difference between main pipes of inlet and outlet of geothermal heat exchangers is measured as $4.1^{\circ}C$. This study propose "Geothermal System COP" which includes not only consumed electric power by compressor but also circulation pumps and auxiliary utilities. By comparing the geothermal system COP with GSHP's performance specification, it is clear that the performances of GHSPs of this site are satisfied with the specification.

• 설비공학논문집
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• 제24권2호
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• pp.196-203
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• 2012

Energy foundations and other thermo-active ground structure, energy wells, energy-slab, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy slabs, filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The natural ground temperature is used as a heat source in winter and a heat sink in summer. The geothermal heat pump system with energy-slab represented very high heating and cooling performance due to the stability of EWT from energy slab. However, the performance of it seemed to be affected by the atmospheric air temperature.

• 한국지열·수열에너지학회논문집
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• 제8권4호
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• pp.32-40
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• 2012

Geothermal heat pump(GHP) systems use vertical borehole heat exchangers to transfer heat to and from the surrounding ground via a heat carrier fluid that circulates between the borehole and the heat pump. An Important feature associated with design parameters and system performance is the local thermal resistances between the heat carrier flow channels in the borehole and the surrounding ground. This paper deals with the in-situ experimental determination of the effective thermal properties of the ground. The recorded thermal responses together with the line-source theory are used to determine the thermal conductivity and thermal diffusivity, and the steady-state borehole thermal resistance. In addition, this paper compares the experimental borehole resistance with the results from the different empirical and theoretical relations to evaluate this resistance. Further, the performance simulation of a GHP system with vertical borehole heat exchangers was conducted to analyze the effect of the borehole thermal resistance on the system performance.

• 한국지열·수열에너지학회논문집
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• 제9권2호
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• pp.8-15
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• 2013

Recently, an interest in the use of renewable energy has been growing up due to the rise of raw material price, international oil price and depletion of fossil energy. Ground source heat pump system has a high efficiency by using the constant temperature of underground and various types of the systems have been installed and utilized in the building. there are few studies on the system performance factors in the SCW system. Furthermore, even though the performance of the system depends on the temperature of heat source, the research on their relationship is rare. In this research, in order to analyze the performance factor for the open-loop system the monitoring of the real building with the standing column well systems and the simulation with building model were conducted.

• 한국지열·수열에너지학회논문집
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• 제13권2호
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• pp.22-29
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• 2017

This study is performed to performance of the combined system the GSHP (Ground Source Heat Pump) system with the Earth tube system using EnergyPlus program. The Earth tube system using fan is characteristics as supply lower (higher) air temperature than outdoor air temperature in cooling and heating seasons, the GSHP system is characteristics as small indoor air temperature variation range. As the results of Earth tube + GSHP system simulation, GSHP power can be reduced than the GSHP single operation as 17.3% in cooling seasons and 32.5% in heating seasons, the GSHP design capacity can be replaced more small size.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.794-800
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• 2008

Due to high oil prices and global warming problems, researching an alternative energy source and decreasing the energy usage will be the key in the future. Unlike other alternative energy sources, geothermal energy is less dependent on the surrounding environment. Geothermal energy is the ideal energy source for buildings due to the simple and space saving installation. The system is semi permanent once it is installed and this will help reduce the energy usage in controlling the climate in buildings. Geothermal energy does not emit carbon dioxide and other gases that are harmful to the environment. Therefore geothermal energy will be the key in solving high oil prices and a decrease in fossil fuels by applying the geothermal energy system to detached house to counter future energy crisis.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.551-558
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• 2012

Due to high oil prices and global warming problems, researching an alternative energy source and decreasing the energy usage will be the key in the future. Unlike other alternative energy sources, geothermal energy is less dependent on the surrounding environment. Geothermal energy is the ideal energy source for buildings due to the simple and space saving installation. The system is semi permanent once it is installed and this will help reduce the energy usage in controlling the climate in buildings. Geothermal energy does not emit carbon dioxide and other gases that are harmful to the environment. Therefore geothermal energy will be the key in solving high oil prices and a decrease in fossil fuels by applying the geothermal energy system to homes to counter future energy crisis.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.195.2-195.2
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• 2011

The borehole heat exchanger of Geothermal Heat Pump (GHP) system should be sustainable and cost effective for long term operation. To guaranty the performance of the system thermal Response Tests (TRTs) with simple recommended procedures have been applied in many countries. Korea government developed a standard TRT procedure in order to control the quality on GHP projects. In the TRT procedure interpretation method has a rule that data set has to be interpreted by the line source model(LSM). The LSM employes some assumptions that surrounding medium is homogeneous and the line source is infinite and constant heat flux, however real ground condition is unisotropic and heterogeneous, and showing regional or local ground water flows in many cases. We need to develope improved evaluation models to estimate accurate ground thermal conductivity with respect to geological and influence of ground water because current TRT standard test procedure has limitations to be applied for every locations and system. This study surveyed the uncertainty of the thermal parameters from the interpretation method considering different evaluation period. The interpretation of 208 TRT data sets represents limitations of LSM application that some obtained ground thermal conductivities are statistically unstable and convergence time of ground thermal conductivity over test period shows trends responding the length of test period. This evaluation study will be helpful to provide some effective procedure for the thermal parameter estimation and to complement current TRT standard procedure.