Thermal Response Test Of Buried Pipe And Evaluation Of Shallow Geothermal Energy Resource In Key Cities Of Ningxia

Shallow geothermal energy is an clean energy and characterized by its wide distribution，rich reserves，shallow burial，less pollution，high efficiency and so on. In order to research theshallow geothermal energy in Ningxia HuiAutonomous Region，the suitable divisions andresource evaluations of shallow geothermal energy in four cities，which are Yinchuan，Shizuishan，Wuzhong and Zhongwei，have been done on the basis of field survey andanalyzing the research of our predecessor. The conclusions are as follows:(1)By arranging and analyzing the meteorological data， geologic data andhydrogeological data of the study area，the meteorological characteristics，the terrains andlandforms，the geology and geological structures，the hydrogeological conditions and thesupplement，runoff and draining of groundwater in the four cities are determined.(2) The principles，the conditions and procedures of the thermal response test of the burialpipe are introduced. And then the low-power steady heating test at4Kw power and thehigh-power steady heating test at8Kw power are proceed. The comprehensive coefficient ofsoil heat conductivity of the test is obtained by processing and analyzing the test data.(3) The FLUENT software is introduced，and the3D single U buried pipe numericalmodel are built by GAMBIT software. Then the numerical model is imported into FLUENTsoftware to simulate the soil temperature. The analytical studies of the heat exchange betweenU buried pipe and soil and the turbulence models, which are used in the simulation, have beendone in theory. The numerical models are applied to precede the48hours3D numericalmodel of buried pipe according to its summer pattern. The model are tested and verified onthe basis of the parameters and results obtained from single U buried pipe heat respond test inYinchuan. When the model is proceeding14hours, the maximum error between the simulatedvalue and the test value is0.3℃，which is within the permissible range and proves that thefeasibility of numerical model. And then the soil temperature field of the system is simulatedby using the model which works60days according to its summer pattern, the influentialradium is decided to be2.53m. All those works lay the foundation for evaluating the availableshallow geothermal energy in the most suitable zone and the suitable zone of the burial pipeheat pump system.(4) According to the calculation request of the relative standard and the existing researchachievements， the calculation parameters used in the process of evaluating shallow geothermal energy are determined based on analyzing the existing suitable divisions of theburial pipe heat pump system and groundwater resource heat pump system in Ningxia. Thenthe heat capacity of shallow geothermal energy，the heat transfer power of the burial pipe heatpump system and groundwater resource heat pump system of the four cities–Yinchuan,Shizuishan, Wuzhong and Zhongwei are calculated respectively. This is the first time to makethe quantitative assessment of shallow geothermal energy in Ningxia.