U型地埋管换热器传热性能数值模拟OA

Shallow geothermal energy,as a clean and environmentally friendly renewable energy source,holds significant im-portance for the transformation of China's energy structure and the achievement of its"Dual Carbon Goals".However,current research on conventional shallow geothermal energy has mainly focused on depths below 200 meters,while research on deeper shallow geothermal energy has been relatively limited.This paper is based on the demonstration project for the development and utilization of shallow geothermal energy in the Langfang area.Numerical simulations of shallow-buried pipe heat exchang-ers were conducted using PE-RT single U-250 m and PE-RT single U-300 m pipes as the subjects of study.Results indicate that increasing the flow rate of the circulating medium and reducing the wall thickness of heat-exchange pipes can enhance the heat-transfer capacity of heat exchangers.However,during actual system operation,factors such as heat transfer capacity,heat pump unit performance,circulation pump power consumption,and safety performance must be comprehensively consid-ered.Additionally,based on the actual geothermal geological conditions and energy consumption patterns in the Langfang re-gion,during the winter and summer operating periods,the thermal influence distances for PE-RT single U-250 m are 3.9 m and 2.7 m,and for PE-RT single U-300 m are 4.1 m and 2.8 m(temperature difference threshold:0.2℃).Through long-term stability analysis of inlet and outlet water temperatures,it was found that the system's heat-exchange performance shows a certain degree of attenuation.In practical engineering applications,adopting an intermittent operation mode can help improve the energy efficiency of the system's heat exchange.This research will provide valuable guidance for the development and uti-lization of shallow geothermal energy.