| Shallow geothermal energy defined as the clean energy of the 21 st is one of the key projects about the future of energy-saving,environmental protection,green development.In recent years,our country has also raised a development shallow geothermal energy boom.The core technology of using shallow geothermal energy is soil source hot pump system,using thermostat of Earth temperature field to provide heat in winter and make refrigeration in summer.The running of the hot pump system makes geothermal field in the surrounding rock mass of geothermal heat pump system ground heat exchanger changed compare to the original ground temperature field,and it changed year by year.This thesis based on the "Beijing LiLai garden FuHua plots building group" as research projects,set up monitoring holes for observation and collection to obtain large amounts of data.Choose reasonable parameters according to the spot stratum condition,regional tectonics,hydrogeological condition and use TOUGH2 program to establish ground temperature field of buried pipe calculation model,conclude:(1)As the ground source heat pump system running,break the original balance in the rock and soil temperature field around ground heat exchanger,its geothermal temperature curve is regular heating and cooling;(2)Because of the running of the heat pump system,quickly broke the rock and soil temperature field around ground heat exchanger original equilibrium state,annual ground temperature of the earth geothermal field rise steadily,rise tend is temperature increases faste in the early as the system operating,then gradually slowe;(3)Vertical ground heat exchanger of the heat pump system heat change with depth.From the surface to 1/2 of the ground heat exchanger is the main heat transfer area,accounted for more than 50% of the overall heat transfer.(4)By using field monitoring and TOUGH2 process simulation,system runs 5 years,rises 0.22 ? annual average.for individual buildings,it can be thouhgt that the temperature change of the surrounding rock mass is smaller.According to the established numerical model of temperature field and make a economic analysis of the ground source heat pump system,we know that geothermal field in the surrounding rock mass of geothermal heat pump system ground heat exchanger is changing and increased year by year after the system run,but the impact to rock around single building is limited.The surrounding rock and soil temperature field change can be mitigated,the ground heat exchanger failure can be avoided and make orderly developments and utilizations of shallow geothermal energy as long as we consider the structure of the surrounding rock and soil,and make a reasonable temperature heat change anticipation as the heat pump system running,and select a reasonable construction plan and equipment selection of the program when the ground heat exchanger is originally designed. |
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