Research On Water-heat Coupled Model Of A Groundwater Source Heat Pump System In Anyang

Compared with ground heat pump systems,water source heat pump systems have advantages on strong heat exchange capacity,saving space and low cost;meanwhile compared with surface water,the temperature of groundwater is so stable that heat pump systems could run efficiently and reliably.Thus the groundwater source heat pump systems are widely used in recent years.Although groundwater source heat pump systems have some advantages,e.g.stability,reliability and energy conservation,they still face some underground engineering problems,and lack of systematic assessment of environmental impact on groundwater.It is of great significance for optimal design,improving environmental benefits and economic efficiency of heat pump systems to study its impact on groundwater environment.A numerical model was developed by using TOUGH2 to simulate the changes of geothermal field and predict the future evolution.The differences and impact of thermal breakthrough under different schemes of well pattern were compared.The conclusions are as follows:1)The influence radius of hydrodynamic field is less than 100m,and the influence radius of temperature change is about 45 m.In the coming years,the hydrodynamic field and temperature field is relatively stable,without further expansion.In other words,other adjacent heat pump systems beyond this distance will not be disturbed.2)Aquifers with different lithology characters have different responses to the recharge water.Temperature change in clay layer is much smaller than that in other aquifers,the magnitude of the temperature change in sandy aquifer is less than that in gravel aquifer.That is because aquifers with high seepage velocity convectively transfer heat much easier,which therefore results in large amplitude of aquifers temperature.3)Comparison of heat transfer under different well pattern showed that the recharge activity has less impact on temperature when the pumping well is in the upstream,and the efficiency of energy extraction is higher and more stable.As a basis for pumping wells layout,the effect on pumping wells with different well spacing was simulated to determine the reasonable well spacing.It is determined to 50m.The determination of reasonable well spacing has guiding significance for scientific management of practical engineering.While it can be referred by other potential projects with similar hydrogeological conditions and same pumping-recharge modes.