| Ground-water Heat Pump (GWHP), as a kind of many categories of ground source heat pump, is a technology which transforms low-order thermal energy forming by absorbing solar energy and geothermal energy in shallow groundwater to high-order thermal energy by heat pump principle. Energy conservation and environmental protection are two issues of the world sustainable development. With the reduction of conventional energy resources and the concerns to environmental protection, the technology producing energy from underground water by source heat pump is widely developed in domestic and foreign because of its many properties, such as cleanness, no pollution, and sustainable use. Therefore, the research on water source heat pump system has significant value and urgency.This paper combined the National Natural Science Foundation project "The research on THCB coupled transport mechanism of water source heat pump" (NO.40972172) and simulated underground aquifer and hydro-thermal coupling effect of water source heat pump using hydro-thermal coupled numerical simulation software TOUGH2. This paper began with introductions to TOUGH2 and descriptions to BORDEN storage test, and then established TH coupled model of BORDEN storage. After validation to the model, TH coupled model of water source heat pump in multi-well production and injection was further set up. Moreover, the effects of factors such as relevant hydrological geology parameters, production and injection arrangement and underground flow field on the evolution of underground temperature field were also simulated. In the end, we simulated the actual project-Zhongxing Commercial Building in Shenyang and provided theory reference to project design. This paper will discuss from following 3 parts:Part I: First of all, the paper introduced the relevant information of TOUGH simulation platform, the development situation of TH theory and the Canadian BORDEN site experiment and monitoring data. Based on above content, we deduced the control equation of TH coupled theory of TOUGH2, and then gave the pressure and temperature boundary conditions, initial conditions of equations. The TH coupled numerical model of BORDEN storage energy test was built. Compare simulating results with the observational data, we verified the TH coupled numerical modle.Part II: Based on the modle varifiation in the third chapter, a TH coupled modle with 300×200×100m in three production wells and three injection wells was built. By changing relevant hydrological geology parameters, pressure, temperature, boundry condition, initial condition, the well location of internal source-sink and underground flow, we studied the corresponding variation of gound temperature field. The results showed that the greater the pumping and injecting volume is, the faster the temperature in aquifer decreases with time, and the temperature recovers slower in the recovery period. In isotropic conditions, permeability coefficient and porosity has a slight effect on the temperature field of aquifer; but in the case of anisotropy, in particular the horizontal permeability coefficient is bigger than vertical one, the temperature in the aquifer drops faster with the increase of penetration ratio. With the spacing increase between pumping wells and injection well, the temperature in pumping well drops smaller; the closer the spacing, the faster the temperature descreases and it also reduces the time of thermal breakthrough. The size of aquifer thickness reflects its storage capacity; in certain pumping load conditions, the thicker the aquifer thickness is, the smaller the change of groundwater temperature field is, as well as the temperature drop of pumping wells. Different seepage velocity and seepage direction also has an important effect on the geothermal field; if the pumping wells are arranged in the upstream of seepage direction, it is very favorable to delay thermal breakthrough and recover the temperature in temperature field.Part III: According to the reaearches on TH coupled numerical model in the third and fourth chapter, and hydrological geology parameters supplied by pumping tests and on-the-spot survey of Zhongxing Commercial Building in Shenyang, we established TH coupled model in multi-well production and injection, studied the optimum design of the project, and then predicted the temperature evolution of temperature field in 3 years. The results showed that the design met heating and cooling requirements, which supplied references for project, s run.At last, we concluded a series of study results, and then raised some shortcomings of this study, moreover a series of suggestions about water source heat pump, s actually existing problems and future development were put forward. Key word: water source heat pump, multi-well system, geo-temperature field, TH coupled model, thermal breakthrough, numerical simulation.
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