Study On The Theory And Application Of The Ground-water Heat Pump Wells

The ground-water heat pump air conditioning system is widely used in the world for its advantages of high efficiency,environmental protection and stability.The operation process of system is the process that human makes use of ground water heat energy,and the core is the pumping-recharge cycle of wells group.At present,there is no systematic theoretical method for groundwater source heat pump pumping and recharge wells,but the theory of the pumping and recharge wells system and the problem that the long-term operation of the system can make impact of groundwater are worthy of attention.So it is of great theoretical significance and application value to study the theory of the water source heat pump pumping and recharge wells and the methods of the groundwater monitoring and evaluation.This paper relies on the Shanxi water conservancy science and technology projects in "Studies of Xi'an water source heat pump pumping and recharge parameters optimization test and applicability",and Shanxi province natural science fund project "Xi'an city water source heat pump pumping and recharge wells mathematical model research project".Taking Xi'an city as an example,research on the theory of the water source heat pump pumping and recharge wells and the methods of the groundwater monitoring and evaluation,the main research contents and conclusions are as follows:1.Determine hydrogeological parameters of pumping and recharge wells.Linear graphic method was used to solve hydrogeological parameters of confined penetrating pumping well.The variation rule of the hydraulic conductivity of recharge wells in groundwater source heat pump system was studied by doing two recharge tests.The optimal method for solving the hydrogeological parameters of the recharge wells with the hydraulic conductivity as the attenuation function was proposed.The results were compared with those of the other methods for the hydraulic conductivity as constant and the hydraulic conductivity as variables.2.Analysis of influencing factors of groundwater source heat pump pumping and recharge wells.According to the experimental data,the influence of the recharge yield was analyzed and discussed.It was conducted that the higher the recharge yield was,the higher the water level was,and the stronger the initial permeability of the recharge wells was,but at the same time,the hydraulic conductivity decreases faster with time.There is a certain relationship between the hydraulic conductivity of recharge wells and the recharge time and the recharge yield.3.Set up the mathematical model of pumping and recharge wells in water source heat pump system.When it was in a interfering condition and the hydraulic conductivity of pumping and recharge wells was a variable,the mathematical model of the drawdown or raise in the pumping and recharge wells was set up according to the principle of superposition.Furthermore,the mathematical model of the drawdown or raise at any point was set up when the hydraulic conductivity was a variable.By introducing the cylindrical coordinate system,the surface of the drawdown or raise in the pumping and recharge wells was set up.When there were one pumping well and two recharge wells,the surface of the drawdown or raise was analyzed and drawn on the basis of test data.4.Determine the optimal setting scheme of water source heat pump pumping well.Based on the hydrogeological characteristics of the study area,four kinds of well layouts of one pumping well and two recharge wells system and eight kinds of well layouts of one pumping well and three recharge wells system were simulated numerically by software FlowHeat1.0.And three aspects of analysis were carried out to determine the best well arrangement,which includes the duration of thermal breakthrough,the change of the underground temperature field and the influence degree of the seepage field.Different well spacing were simulated numerically for two conditions and the reasonable well spacing of the optimal well layout were determined according to the change of temperature with time and well spacing.5.Study on the methods of the groundwater monitoring and evaluation that influenced by ground-water heat pump system.Taking Xi'an city as an example,researching the optimization method of groundwater monitoring network and the evaluation and prediction method of groundwater quality.