红层地区地下水源热泵对地下水温场的影响

地下水源热泵是地源热泵中造价最低、发展较快的一种开发利用浅层地热能资源的热泵系统。此前的研究主要是以第四系松散层内孔隙水作为热源对象,而对红层地区地下水的研究尚为空白。选取重庆红层基岩裂隙水为热源研究对象,采用对井系统带制冷(热)荷载进行试验,同时布置观测孔和温度、水位、流量等测量装置,获得试验过程中各孔内不同深度水温和水位、流量等观测数据,分析得到地下水温度场初始温度分布特点、试验过程中各孔不同深度的温度变化特点、地下水温度场在空间上随时间的变化特点等。分析结果表明:场地内地下水温场的变化主要受天然地温场及初始温度、注水井位置、注水口深度与注水温度等因素的影响。推测注水导致的温度影响范围的边界为:平面上以注水点为圆心,呈不对称近椭圆状;空间上,则以注水点为球心,呈不对称近橄榄球状。研究成果可为红层地区地下水源热泵的进一步开发利用研究提供参考。

A preliminary experimental investigation on groundwater temperature field influenced by groundwater source heat pump (GWHPS) in red beds area

Groundwater heat pump systems (GWHPS) is a kind of shallow geothermal energy utilization approach with the lowest cost, and it develops very fast in recent years. Previous study mainly focused on the pore water in the Quaternary unconsolidated formation, however, the research on groundwater in red beds area is still blank. In this paper, taking the bedrock fissure water of red beds in Chongqing as the research object, a series of pair experiments were conducted successfully. During the experiments, some devices for measuring water temperature, water level and flow rate are placed in observation and testing wells. Water level, flow rate data and the duration curves of water temperature at different depths of every wells were obtained. According to the above data, the initial distribution and spatial and temporal variation characteristics of groundwater temperature field were analyzed. Results showed that the variation of underground water temperature field in the site was mainly affected by the natural ground temperature field and initial temperature, the location of injection well, the depth of water injection nozzle and the injection water temperature, etc. It is speculated that the boundary of the temperature influence range caused by water injection are as follows: on the plane, the boundary shape is asymmetric near ellipse with injection well as the center of the circle, while in space, the injection well becomes the approximate ellipsoidal core of the temperature field boundary. The research results can provide some references for the further development and application of ground water source heat pump in the red bed area.