Journal of the Geological Society of Korea (지질학회지)

The Geological Society of Korea (대한지질학회)
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Influence of open and closed loop geothermal cooling and heating systems on hydrogeological properties

개방형과 밀폐형 지열냉난방시스템이 수리지질학적 특성에 미치는 영향

  • Received : 2013.11.28
  • Accepted : 2013.12.31
  • Published : 2013.12.31
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Abstract

This study was conducted to evaluate the influence of open and closed loop geothermal cooling and heating system on hydrogeological properties using time series data of water temperature, groundwater level and electrical conductivity measured at well used in open loop geothermal system (OLGS) and monitoring well of closed loop geothermal system (CLGS) for approximately 30 months. The water temperature, groundwater level and electrical conductivity were hourly measured and time series analysis was applied using their daily averages. The water temperature fluctuation was significant in observed data according to the load of OLGS. However, the water temperature returned quickly to base level when OLGS was not operated. Operating of OLGS did not significantly influence the groundwater level and electrical conductivity. The groundwater level and electrical conductivity did not show significant correlation with precipitation because they were changed by operating OLGS, regardless rain events. Operating of CLGS did not greatly influence the water temperature, groundwater level and electrical conductivity. In addition, groundwater level and electrical conductivity did not have significant correlation because of influence of water being frequently supplied to lawn on field around monitoring well. In this study, OLGS and CLGS did not significantly influence hydrogeological properties of groundwater during the study period. However, long-term monitoring for geothermal cooling and heating systems is necessary because these geothermal systems can affect the hydrological properties of groundwater with scale and operating type of systems.

이 연구는 개방형 지열냉난방시스템에서 사용 중인 관정과 밀폐형 지열냉난방시스템의 관측공에서 약 30개월 동안 측정된 수온, 수위 및 전기전도도의 시계열자료를 이용하여 개방형과 밀폐형 지열냉난방시스템이 지하수의 수리지질학적인 특성에 미치는 영향을 평가하기 위해서 수행되었다. 수온, 수위 및 전기전도도를 매시간 측정하였으며 측정된 자료의 일평균자료를 이용하여 시계열분석을 하였다. 개방형 지열시스템에서는 시스템의 부하에 따른 수온변화가 뚜렷하게 관찰되었지만 시스템이 운영되지 않는 기간에 수온이 빠르게 회복되었다. 그러나 수위와 전기전도도에는 크게 영향을 주지 않았다. 개방형 지열시스템에서는 강수량과 상관없이 시스템의 운영이 수위와 전기전도도에 영향을 주어 강수량과 이들의 뚜렷한 상호연관성은 관찰되지 않았다. 밀폐형 지열시스템은 수온, 수위 및 전기전도도에 큰 영향을 주지 않은 것으로 평가되었다. 또한 관측정 주변의 잔디에 빈번하게 물이 살포되어 수위 및 전기전도도가 강수량과 뚜렷한 상호연관성을 보이지 않았다. 이번 연구에서는 지열시스템이 지하수의 수리지질학적인 특성을 크게 변화시키지 않는 것으로 평가되었지만 시스템의 규모와 운영방식에 따라서 지열시스템이 지하수의 수리지질학적인 특성에 영향을 줄 수 있으므로 지열시스템에 의한 영향을 명확하게 평가하기 위해서는 지속적인 모니터링이 필요하다.

Keywords

Acknowledgement

Supported by : 환경부

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