Research On The Reasons Of Water Quality Variation In Fracture-karst Induced By A Ground Water Heat Pumps In Chi Zhou

Shallow geothermal energy has broad prospect for development and utilization, while ground water heat pumps(GWHP) is an important way to achieve it. Looking at the results of previous studies,there are few ones on the impact of groundwater quality which produced by the operation of water source heat pumps.The paper chose the Hongsen edifice as the research project which is the more representative projects of ground water heat pumps in Chi Zhou.Water quality was evaluated and hydrochemical type wasanalyzed on the basis of hydrometeorological, geological, hydrogeological information and water quality data.Then, establish the groundwater flow numerical simulation model by Visual MODFLOW software. Conduct scientific prediction on the scope of the groundwater flow field causde by the water source heat pump systerm.According to the impact mechanism of the regional hydrogeological conditions that carry out the causes of water quality analysis of variance.Conclusions are listed as follow:(1) On the basis of groundwater quality data,evaluation factorswere selected and water quality evaluation was carried out, results show that the run of the system has little effect on water quality category of the project in Chizhou City.(2)Based on Piper-diagram drawn byRockWare AqQA, the hydrochemical type analysis in the research area shows that, there is a certain impact on the groundwater chemical type in the area of ChizhouCity, due to a substantial increase of SO42-, the hydrochemical type changes from HCO3-Ca to SO4-Ca. (3)According to hydrogeological conditions of Chizhou County, hydrogeological conceptual model was established by Visual MODFLOW. Conduct scientific prediction on the scope of the groundwater flow field causde by the water source heat pump systerm,results show that the impact of the groundwater flow field is the greatest one in the condition of maximum exploitation and maximum conditions period of the systerm; and under this condition the range of the landing funnel is 1.7km2 caused by 100 percent recharge,the largest drop depth is about 0.8m nearby the umping wells;Corresponding thereto,a local district of water level rises is formed in the vicinity of the recharge wells, the maximum water level on the appreciation is about 0.65m. Visible, the scope of the groundwater flow field causde by the water source heat pump systerm is small.Therefore,the scope of water quality variation is small.