The Theory On Heat Transfer Of Vertical Ground Heat Exchanger And The Test Method For Parameter Of The Rock-soil Thermal Properties

As the pollution of the environment and the lack of energy become more and moreserious, the development and utilization of new energy already attract attention ofgovernments. Geothermal energy is a typical kind of clean and renewable energy. Theground source heat pump is the main mode of geothermal energy exploitation. Among them,vertical type ground source heat pump can save the energy and protect the environmentmost. Vertical type on ground source heat pump nature of energy conservation andenvironmental protection is not necessary. The key is to see if its design is reasonable or not.When we design the ground source heat pump system, we must set the geotechnical thethermal physical parameters at the first place. If this parameter is not accurate, it may causethe system design for insufficient heat, and it also may cause the increase of the initialinvestment system, which affect the ground source heat pump technology promotion.In order to provide more accurate basic data for the ground source heat pump design,this paper do a thorough study to the thermal physical parameters of geotechnical test. Theconcrete contents are as follows:(1) use virtual heat source method to inference the2ndsteady-state model in drill to work out the expression of the transmit heat resistance in drill,and use green function to inference an unlimited long-term heat source model out of drill, soget the theoretical answer to the ground heat exchanger with the surrounding rock transmitheat model.(2) calculate geotechnical thermal parameters inversely by using the fminsearchparameter of the unconstrained optimization algorithm and genetic algorithm into itsprocess, and focus on making a detailed description of working out geotechnical thermalparameters inversely by using genetic algorithm.(3) taking a heat response test in a factoryworker dormitory in Shanxi as an example, use the fminsearch parameter of theunconstrained optimization algorithm and genetic algorithm to realize not only the twoparameters estimation: geotechnical thermal conductivity and geotechnical volume specificheat but also the three parameters estimation: geotechnical thermal conductivity,geotechnical volume specific heat and backfill material thermal conductivity and use the slope method to verify the result which is calculated inversely by parameter estimationmethod.(4) do a sensitivity analysis to the error of the buried tube depth, geotechnicalinitial temperature, the thermal conductivity of backfilling materials and the drillingmainland buried tube center distance.(5) use MATLAB toolbox of PDE to do simulationstudies of the ground heat exchanger around the temperature field of geotechnical, and dosensibility analysis to many factors which affect temperature field of geotechnical, and givethe running time and unit YanMi heat transfer heat action radius of the conversion ofreference formula, and use PDE toolbox to do a simulation analysis on pipeline networkburied tube in a factory worker dormitory in Shanxi.This paper studies on promotion ground source heat pump system has an importantmeaning and reference value and has quite an important practical significance to usegeothermal resources reasonably, reduce the consumption of other regular energy, protectenvironment and so on.