[A-HW07_29PO1] Insight into change and evolution in hydrology

[AHW07-P06] Change of groundwater condition by operation of geothermal heat pump

PARK Youngyun¹、MOK Jong-koo²、PARK Yu-chul²、*LEE Jin-yong¹ (1.Department of Geology, Kangwon National University, Republic of Korea、2.Department of Geophysics, Kangwon National University, Republic of Korea)

キーワード：open loop geothermal cooling and heating system, closed loop geothermal cooling and heating system, time series analysis, groundwater level, groundwater temperature, Korea

This study was conducted to evaluate the influence of open loop geothermal cooling and heating system (OLGCHS) and closed loop geothermal cooling and heating system (CLGCHS) on temperature and water level of local groundwater. For this study, groundwater temperature and level were measured daily using level logger at two sites where OLGCHS and CLGCHS are installed for approximately 30 months. In OLGCHS, fluctuation of groundwater temperature was similar to seasonal variation of ambient air temperature. However, this is not attributed to influence of air temperature. The groundwater temperature was fluctuated according the load of OLGCHS. The groundwater temperature was largely changed by operation of OLGCHS in summer compared to those in winter. These results represent that load of OLGCHS in summer is larger than that in winter. The groundwater levels were mainly controlled by precipitation and were slightly influenced by operation of OLGCHS. In CLGCHS, the groundwater temperature and level did not affected by operation of CLGCHS. The groundwater temperature was changed with 3^oC. The groundwater level was mainly influenced by precipitation because groundwater is not used directly in CLGCHS. In addition, response of groundwater level for precipitation was slower than those at OLGCHS because of difference of hydraulic conductivity. These results show that groundwater temperature and level did not significantly changed by OLGCHS and CLGCHS. However, it is necessary that long-term monitoring of groundwater temperature and level at sites, where OLGCHS and CLGCHS are installed, because OLGCHS and CLGCHS can affect the hydrological properties of aquifer with scale and type of use of geothermal energy. This work is supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010) and by the Korean Ministry of Environment under "The GAIA project (No. 171-101-011)".