【作者】 程群英；

【导师】 孙纯武；

【作者基本信息】 重庆大学 ， 供热、供燃气、通风及空调工程， 2004， 硕士

【摘要】 本课题是继国家自然科学基金的资助下进行了浅埋竖直管换热器和水平埋管换热器地源热泵的采暖和供冷特性研究后，对原有实验台进行改造的基础上进行的50米深埋U型管地下换热器的性能特性研究。 本文主要论述了50米深埋U型管地下换热器冬季运行后，过渡季节期间地温的恢复规律，并对1#井和3#井在不同运行工况下进行性能分析，最后采用圆柱源理论模型对本地源热泵系统性能进行模拟，得出了模拟与实验数据的吻合程度。 在冬季向夏季过渡期间，热泵系统停止运行，大地温度开始向远边界处大地温度逐渐恢复，在运行季结束初期，地温恢复较快，之后慢慢趋于平稳。根据测试结果所知，-5m地温在恢复3个月后基本保持稳定状态，在进入夏季运行的前一个星期，-20m地温达到了19.01℃，-35m地温达到了18.84℃，-50m地温达到了19.24℃，地温恢复达到了95％以上。 本系统夏季分别对3#井单管以流量645L／h工况进行性能测试，以及1#井变流量性能测试，埋管侧水流量分别为645L／h、700L／h，760L／h。测试结果表明：不管是从制冷性能系数还是从单位井深换热量来比较，760L／h这一工况均优于其它两种流量工况，其平均单位井深换热量为69.47w／m，系统制冷性能系数为3.44w／w，传热系数为6.40w／m．℃。 根据测试数据所反映的结果，对热短路现象进行分析，随着地下埋管侧的水流量增加，热短路越趋于严重。 在地源热泵运行特性理论研究和实验研究的基础上，依据圆柱源理论，建立起了变热流条件下地源热泵系统的模拟模型。模型验证结果表明，进出水温度的模拟值与实测值的最大误差为6.33％，在一定程度上验证了该模型的准确性和有效性。 利用此模型模拟了地下埋管内流体的平均温度、平均进口温度和平均出口温度，以及进行系统热短路的模拟分析。更多还原

【Abstract】 After the research about performance of shallow buried vertical ground heat exchanger and horizontal ground heat exchanger in cooling and heating operation , the paper will continue to discuss the performance of 50-meter-deep buried vertical U-tube ground-coupled heat pump in cooling operation .The paper mainly reports the ground temperature change after the heating operation of 50-meter-deep buried vertical U-tube ground-coupled heat pump and performance of system with several flow rates in summer , then the simulation of the performance by cylindrical heat source model.In the transition season ,the ground temperature gradually resumes, then goes to stabilization . According to the experimental data ,the temperature under 5 meters keeps constant; the temperature under 20 meters, 35 meters, 50 meters attach to 19.01 ℃,18.84℃, 19.24℃ respectively before the cooling operation. This resume of ground temperature attaches to 95%.To study on the law of ground cooling transfer ,the performance of system in 3#well is tested when the flow of rate is only 6451/h;several different flow rates of U-tube such as 6451/h, 7001/h, 7601/h are applied for l#well. The flow rate of 7601/h is preferable by comparison of coefficient of heat exchange and average quantity of heat per meter. In the operation of the flow rate of 7601/h in 1# well ,the coefficient of heat exchange , average quantity of heat per meter and coefficient of performance are 6.40w/m℃. ,69.47w/m, 3.44w/w.According to the analysis of the testing results , the effects of thermal short-circuiting between two legs of the U-Tube become more serious with the flow rate increasing.Based on the theories and experiments about GSHP, the cylindrical heat source model has been developed for the simulation of heat transfer over a vertical U-tube ground heat exchanger when the flow rate is changeable. The simulation shows that the maximal temperature error of entering and exiting water is 6.33%.The predicted data calculated by the model agree reasonably well with the experimental data.The model produces the average temperature average entering temperature average exiting temperature of the flow in buried pipe. At last the short-circuiting of system is analyzed.更多还原