换热介质关键参数对中深层地埋管取热的影响OA

The research progress on the influence of key parameters of heat exchange media on heat extraction from medium and deep buried pipes is analyzed,and prospects for future research directions are put for-ward.As the flow rate increases,the heat extraction ca-pacity of medium and deep buried pipes enhances,while the energy consumption of the system increases,and the resulting cost increase cannot be ignored.Tak-ing into account the efficiency and cost of heat extrac-tion,the selection of the optimal flow rate of heat ex-change media has become a research hotspot.The ex-ternal inflow and internal outflow of heat transfer me-dium is the preferred flow direction of the medium and deep casing buried pipe.Lowering the inlet tempera-ture of heat exchange media can help improve the heat extraction efficiency of the middle and deep buried pipes,but it is easy to lower the outlet temperature and needs to be adjusted reasonably.From the perspective of improving heat extraction performance,CO2 can be used as an effective heat exchange medium for medium and deep buried pipes.In the middle and deep buried pipe scenes with a depth of more than 3 500 m,water as a heat exchange medium may be one of the more suitable choices.Nanofluids also have great potential and can be expected to develop in the future.The exist-ing research mainly focuses on the heat extraction per-formance and economy of the middle and deep buried pipe systems,and the research on these two aspects is relatively isolated,and how to achieve the best balance between heat extraction performance and economy is still worth studying.Most of the existing studies focus on shorter cycles and do not fully consider the impact of long-term operation.Therefore,conducting research on the long-term heat extraction performance of me-dium and deep buried pipes is the prerequisite for en-suring the efficient,stable and sustainable develop-ment and utilization of medium and deep geothermal energy.