The Study On GSHP System’s Geothermal Equilibrium In Extreme Cold Area

As a reliable, high efficiency, economy, environmental protection models of airconditioning, The ground-source heat pump raised widespread concern in HVACindustry in recent years, and has become one of the frontier subjects in the field ofbuilding energy saving. However, in cold regions, due to the weather conditions, hereis a thermal imbalance phenomenon in the process of ground-source heat pumpsystem operation, and has become a constraining bottleneck problem of its large-scaleapplication.In order to find a technology to solve the problem of ground-source heat pumpsystem heat unbalance in severe cold regions, this thesis discusses with independentintellectual property rights of the control area partition of thermal compensationmethod and other related technical problems. The main research contents are asfollows,1.According to do the test of thermal for the underground soil of the project, thesoil thermal physical parameters can be measured;2.Using simulation software of DeST-c for the dynamic load for buildings;3.Purposing a physical model for the well group of soil heat exchanger by thesoftware of Gambit, and running hourly simulation of heat exchanger for5years bythe Fluent software;4.Analyzing the simulation data on soil heat exchanger well group annualoperation in heating and cooling condition and two transition season;5.Analyzing the simulation data on soil heat exchanger well group5years oflong-term operation;6.Comparing the simulated soil heat exchanger well group in non thermalcompensation mode for5years running and simulation results using control areapartition of thermal compensation mode, verify the feasibility of this method;7.Using a intelligent platform of ground-source pump system to detect the soiltemperature, comparing the measured results with the simulation results, verifying theaccuracy of simulation;The results show that,1.After1year operation of the system, The current temperature of soil decreasedby0.15℃as the initial temperature, and the balance of soil temperature was kept.2.After5year operation of the system, The temperature of soil in the center ofwell groups decreased by0.41℃as the initial temperature, and the balance of soil temperature field was kept.3.The systems in under way of non thermal compensation that is only runningheating mode of other time natural recovery, after5years of operation of soiltemperature and initial temperature lower than4.74℃,the Cooling pit is formed inthe center of well group, and the soil temperature is difficult to recover, resulting inheat pump system cannot continue to operate normally, feasibility of operation andthermal compensation mode the simulation results verify the control area comparedwith thermal compensation method;4.According to the measured the change of soil temperature in the heatingconditions by the ground-source heating pump monitoring platform, the soiltemperature difference and the simulated soil temperature difference contrast curve ofthe soil temperature monitoring hole2#and4#can be seen that the curve fittingdegree is very high and the same comparison, and the simulated values of soiltemperature and soil temperature difference monitoring values are consistent thoughthe comparative data，The monitoring value of soil temperature difference dropped to2-3℃，as same as the simulation results which are1.05-3.15℃,proved that thesimulation result is accurate.Thus, the control area partition of thermal compensation method can effectivelysolve the thermal imbalance of ground-source heat pump system operating in the coldregions, and should be used and popularized.