Research On Heat Transfer Characteristics Of Temperature Field Based On Ground Source Heat Pump

Ground source heat pump has been used as a kind of energy conservation and environmental protection technology.The application of Ground source heat pump is strongly influenced by geological conditions.Chongqing belongs to the bedrock mountain formation,mainly formed by sedimentary rocks.Chongqing has hot summer and cold winter that cause the cooling load in summer is more than the heating load in winter.So the heat absorbed and released by the rock-soil is hard to reach a balance.That will lead to the heat stack in the soil.Based on a building in Chongqing,the Ground source heat pump heat transfer characteristics has been studied through the combination of the simulation and experiment.Then put forward an optimization plan to relieve the problem of heat stack.Firstly,based on research data of Rock energy storage performance and utilization technology research,this research has classified and analyzed the mainly thermal physical parameters,such as thermal conductivity,thermal diffusivity and specific heat capacity,of the rock in Chongqing.And also studied its energy storage performance.The results indicate that the Sandstone and mudstone has good storage performance,and the ground source heat pump is suitable for this area,considering the the geological characteristics of Chongqing.Secondly,single tube and tube nest model has been built in ANSYS.These model has been verified through data acquisited from the experiment platform,and the thermal physical parameter of the rock.Then simulation has been conducted under different heat conductivity coefficient,inlet velocity,inlet temperature and well depth.And analyzed the its impact on the heat exchange amount of the ground source heat pump system.Ten years of simulation under different tube spacing had also been conducted.Results show that there are less heat stack while the tube space is 5 meters,the average ground temperature increased 2.1 ?;while the tube space is 3 meters,the average ground temperature increased 4 ?.Long terms running lead to the heat stack more serious.After this,further analysis about the different rock's heat storage change has been carried out,and the system's economy,energy saving and environment benefits has also been analyzed.Finally,from the aspect of changing load consideration,the scheme of increasing the cooling tower system to alleviate the heat accumulation problem is put forward.The TRNSYS software is used to simulate and analyze the running conditions of the system under different heat dissipation ratio.From the aspects of ground temperature change and unit performance,the optimal energy saving performance is found.Of the program,the program is: cooling tower system in the third year to open,auxiliary cooling ratio of 40%.