• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.697-700
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• 2005

Aquifer Thermal Energy Storage (ATES) system can be very cost-effective and renewable energy sources, depending on site-specific parameters and load characteristics. In order to develop an ATES system which has certain hydrogeological characteristics, understanding of the thermo hydraulic processes of an aquifer is necessary for a proper design of an aquifer heat storage system under given conditions. The thermo hydraulic transfer for heat storage is simulated using FEFLOW according to two sets of pumping and waste water reinjection scenarios of heat pump operation in a two layered confined aquifer. In the first set of model, the movement of the thermal front and groundwater level are simulated by changing the locations of injection and pumping well in seasonal cycle. However, in the second set of model the simulation is performed in the state of fixing the locations of pumping and injection well. After 365 days simulation period, the temperature distribution is dominated by injected water temperature and the distance from injection well. The small temperature change is appears on the surface compared to other slices of depth because the first layer has very low porosity and the transfer of thermal energy are sensitive at the porosity of each layer. The groundwater levels and temperature changes in injection and pumping wells are monitored to validate the effectiveness of the used heat pump operation method and the thermal interference between wells is analyzed.

• Journal of Soil and Groundwater Environment
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• v.26 no.3
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• pp.14-24
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• 2021

Aquifer thermal energy storage (ATES) system uses groundwater thermal energy for cooling and heating of buildings, and it is also often utilized to provide warm water to crops and plants for the purpose of enhancing agricultural yields. This study investigated the potential influences of a ATES system on the geochemical properties of groundwater by simulating the variation of hydrochemistry and saturation index of groundwater during ATES operation. The test bed was installed at an agricultural field, which is mainly composed of an groundwater-rich alluvial plain. The simulation results showed no significant precipitation of mineral phases such as manganese-iron oxide, carbonate and sulfate around the ATES test bed, as well as no debasement of other important water quality parameters. The implementation of ATES system in the study area was appropriate and effective for utilizing the thermal energy of groundwater for agricultural use.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.1 no.1
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• pp.1-8
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• 2005

Aquifer Thermal Energy Storage (ATES) can be a cost-effective and renewable geothermal energy source, depending on site-specific and thermohydraulic conditions. To design an effective ATES system having the effect of groundwater movement, understanding of thermohydraulic processes is necessary. The heat transfer phenomena for an aquifer heat storage are simulated by using FEFLOW with the scenario of heat pump operation with pumping and waste water reinjection in a two layered confined aquifer model. Temperature distribution of the aquifer model is generated, and hydraulic heads and temperature variations are monitored at the both wells during 365 days. The average groundwater velocities are determined with two hydraulic gradient sets according to boundary conditions, and the effect of groundwater flow are shown at the generated thermal distributions of three different depth slices. The generated temperature contour lines at the hydraulic gradient of 0.001 are shaped circular, and the center is moved less than 5 m to the direction of groundwater flow in 365 days simulation period. However at the hydraulic gradient of 0.01, the contour center of the temperature are moved to the end of east boundary at each slice and the largest movement is at bottom slice. By the analysis of thermal interference data between two wells the efficiency of the heat pump system model is validated, and the variation of heads is monitored at injection, pumping and no operation mode.

• Journal of Soil and Groundwater Environment
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• v.22 no.4
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• pp.9-26
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• 2017

When a warm well located downgradient is captured by cold thermal plume originated from an upgradient cold well, the warm thermal plume is pushed further downgradient in the direction of groundwater flow. If groundwater flow direction is parallel to an aquifer thermal energy storage (ATES), the warm well can no longer be utilized as a heat source during the winter season because of the reduced heat capacity of the warm groundwater. It has been found that when the specific discharge is increased by $1{\times}10^{-7}m/s$ in this situation, the performance of ATES is decreased by approximately 2.9% in the warm thermal plume, and approximately 6.5% in the cold thermal plume. An increase of the specific discharge in a permeable hydrogeothermal system with a relatively large hydraulic gradient creates serious thermal interferences between warm and cold thermal plumes. Therefore, an area comprising a permeable aquifer system with large hydraulic gradient should not be used for ATES site. In case of ATES located perpendicular to groundwater flow, when the specific discharge is increased by $1{\times}10^{-7}m/s$ in the warm thermal plume, the performance of ATES is decreased by about 2.5%. This is 13.8% less reduced performance than the parallel case, indicating that an increase of groundwater flow tends to decrease the thermal interference between cold and warm wells. The system performance of ATES that is perpendicular to groundwater flow is much better than that of parallel ATES.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.701-704
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• 2005

Aquifer Thermal Energy Storage (ATES) can be a cost-effective and renewable geothermal energy source, depending on site-specific and thermohydraulic conditions. To design an effective ATES system having influenced by groundwater movement, understanding of thermo hydraulic processes is necessary. The heat transfer phenomena for an aquifer heat storage are simulated using FEFLOW with the scenario of heat pump operation with pumping and waste water reinjection in a two layered confined aquifer model. Temperature distribution of the aquifer model is generated, and hydraulic heads and temperature variations are monitored at the both wells during 365 days. The average groundwater velocities are determined with two hydraulic gradient sets according to boundary conditions, and the effect of groundwater flow are shown at the generated thermal distributions of three different depth slices. The generated temperature contour lines at the hydraulic gradient of 0.00 1 are shaped circular, and the center is moved less than 5m to the groundwater flow direction in 365 days simulation period. However at the hydraulic gradient of 0.01, the contour center of the temperature are moved to the end of boundary at each slice and the largest movement is at bottom slice. By the analysis of thermal interference data between two wells the efficiency of the heat pump system model is validated, and the variation of heads is monitored at injection, pumping and no operation mode.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.399-402
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• 2004

An aquifer thermal energy storage (ATES) model is simulated by FEFLOW according to the scenario of heat pump operation in two layered confining aquifer. The scenario is consisted of 4 steps: 90 days pumping (west well) and waste water injection (east well: 35 $^{\circ}C$), 90 day s stop, 90days pumping (east well) and waste water injection (west well: 5 $^{\circ}C$), and 95 days stop. The injection of the waste water is limited in the second layer and the first layer is aquitard. The temperature distribution at the surface shows low difference with reference temperature and opposit aspect with that of the second layer because the thermal transition through the first layer is very slow. Even though the simulated thermal transition in the aquifer system have a difference with real ATES system, optimal design and operate system can be developed with field tests and operational experience.

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.54-61
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• 2005

An aquifer thermal energy storage (ATES) system can be very cost-effective and renewable energy sources, depending on site-specific parameters and load characteristics. In order to develop the ATES system which has certain hydrogeological characteristics, understanding the thermohydraulic process of an aquifer is necessary for a proper design of an aquifer heat storage system under given conditions. The thermohydraulic transfer for heat storage was simulated according to two sets of simple pumping and waste water reinjection scenarios of groundwater heat pump system operation in a two-layered aquifer model. In the first set of the scenarios, the movement of the thermal front and groundwater level was simulated by changing the locations of injection and pumping wells in a seasonal cycle. However, in the second set the simulation was performed in the state of fixing the locations of pumping and injection wells. After 365 days simulation period, the shape of temperature distribution was highly dependent on the injected water temperature and the distance from the injection well. A small temperature change appeared on the surface compared to other simulated temperature distributions of 30 and 50 m depths. The porosity and groundwater flow characteristics of each layer sensitively affected the heat transfer. The groundwater levels and temperature changes in injection and pumping wells were monitored and the thermal interference between the wells was analyzed to test the effectiveness of the heat pump operation method applied.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.289-296
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• 2012

The aim of this study is to investigate the performance of a heating and cooling system with aquifer thermal energy storage(ATES heat pump system) known as one of the underground thermal energy storage application systems. The ATES system was composed of heat pump unit and ATES, which was installed in a factory building located in Anseoung. The system represented very high heating and cooling performance, and showed nearly constant COP at each heating and cooling season due to the stability of EWT. The economic analysis about an ATES system and a conventional system was also executed. The conventional system adopted an air-conditioner in the summer season and a LNG boiler in the winter season. The payback period of the ATES system was estimated by 6.62 years.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.556-560
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• 2009

개별 대수층에 냉수와 온수를 저장하여 수자원과 냉난방 열원으로 활용하는 방안에 대한 평가를 지열-지하수 부정류 모델링을 통해 수행하였다. 저장 및 회수 가동 시간이 증가함에 따라서 각각의 대수층 내에 온열과 냉열이 축열되는 현상이 확인되었으며, 지하수 유동에 의해 축열된 수체가 지하수 흐름방향으로 이동하는 현상을 확인 하여 지하수 유동이 축열 정도를 결정하는 요인이 될 수 있음을 확인하였다. 설정된 모델에 대하여, 두 개의 개별 대수층 사이의 열 간섭은 거의 없는 것으로 나타났다. 주입과 양수의 가동 횟수가 증가되면, 대수층 축열 효과는 증대되는 것으로 나타났다. 열-지하수 모델링을 통한 온도 예측은 실제 냉난방의 효율성을 결정짓는 수온을 정량적으로 계산할 수 있는 유용한 기술로 평가됨과 더불어, 수자원의 지하 저장을 통해 효율적으로 물을 확보하고 관리할 수 있는 방안이 될 수 있을 것으로 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.596-599
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• 2009

대수층 축열 시스템(ATES)의 효율은 지중에 저장된 열 사이의 간섭에 의해 결정이 되며, 열 간섭에 영향을 미치는 요인들은 시추공 간 이격거리, 대수층의 수리 전도도, 주입/양수량 등이 있다. 따라서 이 연구에서는 지하수-지열 거동 모델링을 통하여 열 간섭이 일어나는 현상과 열 간섭이 시스템 효율에 미치는 영향을 분석하였다. 모델링 결과로부터 이격거리는 작을수록 그리고 대수층의 수리전도도와 주입/양수량은 클수록 열 간섭이 잘 일어나는 것을 확인하였고, 열 간섭 계수가 1일 때는 시스템 효율이 상대적으로 크게 낮아지고, 열 간섭 계수가 1 미만일 때는 변화가 미미한 것을 확인하였다. ATES 를 이용한 냉난방 시스템을 시공 하고 있는 안성 연구지역에 대한 장기 예측 모델링을 수행 하였다. 모델링 결과 이격거리가 80 m 이고, 주입/양수량이 100 $m^3/day$ 일 때, 시스템 가동 7년경과 뒤 여름철과 겨울철에 계산된 시스템 효율은 각각 36 RT 와 31 RT 로 나타났다. 따라서 주입/양수량을 100 $m^3/day$로 했을 때, 냉난방 대상건물의 필요 부하인 20 RT 를 충분히 충족할 수 있을 것으로 판단된다.