【作者】 林元同；

【导师】 余延顺；

【作者基本信息】 南京理工大学 ， 供热供燃气通风及空调工程， 2009， 硕士

【摘要】 近年来国外出现了一种从同一个井内取水和排水的半开式水源热泵系统,通常称为单井循环水源热泵系统。该系统具有初投资低、运行效果良好、节能和环保等优点,具有广泛的应用前景。在美国,相关学者及专家已对其进行了一系列的模拟研究,并在美国东北部等一些地区得到了运用。然而,对其研究国外主要停留在模型建立和系统的一些影响因素方面,仍然没有提出关于单井循环水源热泵的切实可靠的详细设计步骤,国内对其研究才刚刚起步,此系统在中国的适应性或运用可能性还没有相关研究和报道。本文主要建立了单井循环地下水源热泵地下换热系统的渗流和传热数学模型,采用有限差分方法对其进行数值离散并求解;在此基础上研究单井循环地下水源热泵系统地下水的渗流特性,分析循环水流量、Bleed量和井深等主要因素对井外水渗流特性的影响;研究单井循环地下水源热泵系统的传热特性,分析岩石导热系数、渗透系数、Bleed量、地下水初温等因素对单井循环系统传热特性的影响,分析井深对传热特性的影响,比较不同井深下单井循环系统运行效果,分析浅层单井循环系统运用的可行性。得到如下结论:循环水流量越大、Bleed量越大,单井循环系统渗流特性越好;循环水流量的变化对井外渗流速度场的影响要大于Bleed量的影响,循环水流量增加井外渗流速度整体上升,Bleed量的增加是以减少更多的向井外渗出的循环水流量为代价,增加少量向井内的地下水渗流量;传热特性方面,冬季运行最低出水温度随着岩石导热系数、含水层渗透系数、井壁粗糙度、井壁直径、Bleed量、地下水初温的增加而上升,随着取水管内径的增加而降低;单井循环传热特性众多影响因素中Bleed量和岩石导热系数及地下水初温对出水温度影响较大,井壁粗糙度几乎没有影响;浅井替代深井运行理论上可行,保证换热能力的同时降低了初投资;间歇运行效果要比连续运行好得多。更多还原

【Abstract】 In recent years, groundwater heat pump systems that use groundwater drawn from and returned to the same well in a semi-open loop arrangement were proposed abroad, commonly known as Standing Column Well (SCW) systems. It’s a promising technology with low cost, high efficiency, low energy consumption and environmental benefit. A number of authors have reported on it in America, and it has been used in the Northeast of America. However, recent researches are presented to the modeling and affections of standing column wells. No effective, reliable and detailed Design Method is proposed. Few researches were reported about this system in our country. And no research was reported about its adaptability or possibility of use in China.The model of seepage field and the model of heat transfer for standing column well are established. Finite difference method is used to discrete and solve the equations. On this condition, characteristics of seepage flow are studied to analyze the effects of circulating water flow rate, bleed rate and depth of well on the seepage flow of SCWS. And characteristics of heat transfer are studied to analyze the effects of rock thermal conductivity, rock hydraulic conductivity, bleed rate, ground-water initial temperature and etc. on the heat transfer of SCWS. And the effects of well depths on heat transfer are also analyzed to cmpare operation effects of different depths of wells, in order to find out the feasibility of using shallow SCWS.Conclusions can be drawn as follows. With more circulating water flow or higher bleed rate, SCWS have higher seepage flow rate. And the effect of circulating water flow rate is more significantly. With the increasing of mass rate of circulating water, all seepage flow rates along the borehole are increased. However, with the increasing of bleed rate, few groundwater flow in, on the base of more circulating water flowing out of the borehole. On heat transfer, the minimum well temperature in winter increases with rock thermal conductivity, hydraulic conductivity, roughness height of the borehole, borehole diameter, bleed rate, and ground-water initial temperature, and decrease with dip tube diameter. Among these affections, the effects of bleed rate and rock thermal conductivity are more significantly, while, roughness height of the borehole has little effect on heat transfer. Changing deep wells into shallow wells is feasibal, with good heat thansfer effect and low initial cost. The effect of intermittent operation is better than continuous operation.更多还原