Simulation And Analysis On The Performance Of Vertical Ground Heat Exchanger And Engineering Applications

Ground-coupled heat pump (GCHP) is an advanced green air-conditioning system and got greatly concern and application in rencent years, which is energy-saving and enviromental-friendly. It is currently the research frontier within the HVAC field. The scientific and reasonable design of Ground heat exchanger (GHE) will directly affect the system's economy and operational reliability. Some designers blindly adopt the heat flux per unit drilling depth or use the data of a few hours or days in-situ testing as the design criteria, which consequently leads to the unrealiable operation of the system and can't meet the design requirements in some GCHP project. How to analyze the GHE influencing factors and set down a suitable design methodology is the premise to a scientific and reasonable design. The thesis analyzes the coupled relationship among the three parts of GCHP system, introducing a FEM software----ANSYS----to discuss some different influencing factor's effects on the heat transfer of single U-type GHE and GHE bundle.Based on the good study of rock and soil thermophysical properties and in-situ testing, the thesis focuses on the study of the performance of GHE and its temperature fields and gradients by dividing the GHE into finite sections on longitudinal direction, and employing the ANSYS to analyze each sections step by step. By simulating the heat exchange performance of GHE bundle, a reasonable interval of GHE is obtained. In engineering applications, the thsis applies the numerical analysis method to GHE design of a GCHP project in certain residential building, and provides a preliminary design method for applying the numerical simulation in GHE's design.