Research On R&D And Application Of Solid Waste-based Backfill Materials For Ground Source Heat Pump Engineering

In today's society,extensive economic development methods and the limitations of science and technology make the problems of energy waste and environmental pollution continue to intensify,gradually becoming a global problem.People's requirements for the comfort of the living environment continue to increase,which in turn aggravates the energy consumption of building operations.HVAC and hot water systems account for nearly 60%of the energy consumption.In order to achieve energy-saving and emission-reduction targets with high standards,develop new energy extraction and utilization technologies,so as to make full use of limited resources,it is necessary to improve energy utilization by reducing the energy consumption of HVAC systems and hot water systems to protect the environment and save resources,The purpose of meeting consumer needs.As a new type of energy,shallow ground temperature can be used in the construction industry and become a popular new energy source.It has the advantages of renewability and cleanliness.It is an important resource for alleviating the energy crisis and solving environmental problems.At present,shallow ground temperature energy is mainly extracted by ground source heat pump technology.However,due to certain limitations and shortcomings of ground source heat pump technology,it is impossible to achieve high efficiency extraction of low temperature energy,especially in backfill materials and backfill methods.And technological difficulties,to a certain extent,have become obstacles to the development and utilization of shallow geothermal energy.In the process of advancing the development of this technology and improving energy efficiency,backfill materials play an important role.In order to meet the practical needs of improving the efficiency of low-temperature energy utilization,suitable backfill materials and their thermal conductivity ranges must be explored to improve heat exchange efficiency.Based on this,this study relied on the Weifang Beidou Science and Technology Industrial Park project to develop new backfill materials and backfill technology research.Then the specific research is as follows:(1)Based on the previous experience and literature of the research group,determine the approximate formula of the material,after determining the formula,conduct experiments to adjust the proportions,and finally determine the final series formula of the material according to the optimal thermal conductivity range determined by the COMSOL simulation To achieve the effect of adjustable thermal conductivity,through engineering applications,it has been proved that the backfill material obtained by this method has many advantages such as low cost,excellent performance,and strong engineering applicability.(2)Based on the heat exchange mathematical model of the ground source heat pump heat exchange system of the existing buried pipe,establish a numerical model of the flow and heat coupling of the buried pipe,study the relationship between the borehole length,the thermal conductivity of the filling material and the thermal conductivity of the formation,and obtain the filling material The optimal value range of thermal conductivity provides a basis for the research and development of new backfill materials,and establishes the positive effect of the synergy of simulation calculation,engineering survey and formulation design on material development and engineering application.(3)The newly developed backfill material was applied to a buried ground source heat pump project in Weifang.A new thermal conductivity adjustment system was established and applied in engineering.The results were compared with the heat transfer effect of common backfill materials to verify the new type.The applicability of the backfill material to the ground source heat pump system of the buried pipe also reflects the superiority of the new backfill material in the shallow ground temperature energy mining.