不同负荷特性下单U型地埋管换热器换热性能模拟分析

Simulation and analysis of thermal performance of single U-tube ground heat exchanger under different load conditions

文章对单U型地埋管换热器建立二维传热模型,并通过二维截面推移得到其三维模型。运用Ansys热分析软件,分析了某地区在不同空调负荷特性下的单U型地埋管换热器换热性能。模拟结果表明,单U型地埋管换热器在连续负荷作用下,每延米换热量从运行初期的约130 W下降到末期的34 W左右,在连续运行约200 h后基本保持不变;在间歇负荷作用下,每天运行末期的每延米换热量下降缓慢,在运行8 d后基本不变,保持在48 W左右,与连续负荷相比,换热器的热堆积小。

A two-dimensional heat transfer model of the single U-tube ground heat exchanger is established,and its three-dimensional model is achieved based on the two-dimensional section by neglecting the axial heat conduction effect.Through the thermal analysis by Ansys software,the simulation of the thermal performance of the single U-tube ground heat exchanger in a district under different air conditioning load conditions is carried out.The simulation results reveal that under continuous load,the quantity of heat exchange per meter drops from 130 W at the beginning of operation down to 34 W in the end,and keeps almost unchanged after 200 hours＇ continuous operation.While under intermittent load,the quantity of heat exchange per meter at the end of daily operation decreases slowly,and keeps at 48 W unchanged after 8 days＇ operation.Less thermal accumulation is gained under the second operation mode.