Research On The Development And Exploitation Mode Of Geothermal Energy In Shallow Aquifer

Shallow geothermal energy developing in shallow aquifer of massif regions whichoccupy two-thirds of our country’s territory, has the character of wide distribution, rapidrecycling capability and small investment, thus has important application value. However,the factors affecting the geothermal energy in shallow aquifer are numerous andcomplicated,(atmosphere temperature, holding capacity of precipitation soil, water level,etc.) and therefore bring certain difficulty to the effective application of geothermal energyin shallow aquifer. Based on the factors affecting the geothermal energy in shallow aquifer,this paper carried out research on dynamical change of geothermal energy in shallowaquifer and put forward reasonable development and utilization mode, which provideseffective scientific basis for the rational development and utilization of geothermal energyresources in shallow aquifer.Based on water-thermal transport of shallow groundwater experimental base which islocated in Jingxian County, Anhui Province and the long-term dynamic monitoring data offactors affecting shallow geothermal energy (groundwater level, soil temperature, soilmoisture and atmosphere temperature), this paper established numerical model ofwater-thermal transport, analyzed rules of shallow aquifer temperature field in the studiedarea responding to seasonal fluctuations of atmosphere temperature and precipitation,discussed mechanism of groundwater heat migration responding to the river level,water-proof boundary, thus reveals dynamic change law of geothermal energy in shallowaquifer respectively under first terrace hydrogeological conditions, natural conditions andinterferential conditions, and provides support for carrying out research on the developmentand exploitation mode of geothermal energy in shallow aquifer.For Jingxian County Hospital of the studied area, total requiring heating load amounts to5500kw in winter and total requiring cooling load amounts to3850kw. The studied area islocated in the first terrace at the eastern mountain exit of Qingyi River, and has obviouswater exchange with Qingyi River. Based on water level variation process line of QingyiRiver in certain typical year, Qingyi River water level maintains at between27.0-28.0m inwinter, and30.0m in summer. When water level is respectively27.0,28.0,30.0m, the runof groundwater source heat pump system has certain impact on surrounding groundwaterflow field; area of which drawdown is greater than zero is respectively8.1,7.0,6.1km2,responding exploitable geothermal energy is respectively4424,5095,5854kw. Undernatural conditions, cooling load in summer can meet requirement, while the heating load in winter can’t. When Qingyi river water level is29.0m, the exploitable geothermal energyamounts to5586kw, which can meet winter heating load requirement. In terms of waterlevel seasonal fluctuations of Qingyi River, based on the migration and influencecharacteristics of geothermal energy in shallow aquifer, Combined with the example ofworking conditions, Study on the mode of development and utilization of geothermalenergy; this paper can provide reference for the development and utilization of geothermalenergy in similar area.