复合埋管式土壤源热泵系统性能研究

发布时间：2018-07-03 03:01

本文选题：复合埋管式土壤源热泵系统 + 换热性能　；参考：《重庆大学》2015年硕士论文

【摘要】：土壤源热泵作为一种高效节能的可再生能源利用技术,近年来备受关注。目前对土壤源热泵系统性能的研究主要集中在单独采用水平或垂直埋管换热器时土壤源热泵系统的性能研究,而利用水平埋管与垂直埋管联合换热的土壤源热泵系统研究成果还较少。本文将这种采用水平埋管与垂直埋管联合换热的土壤源热泵系统称为复合埋管式土壤源热泵系统,并对其进行研究。本文基于天津市某办公建筑,从热泵机组出力负荷入手,根据建筑实际条件及经济性初步确定两种埋管换热器承担负荷配比,进而制定针对该办公建筑负荷特性的复合埋管式土壤源热泵系统运行控制策略。分别建立水平埋管换热器和垂直埋管换热器三维传热模型,通过分别计算分析水平埋管和垂直埋管换热器的换热性能,完成复合埋管式土壤源热泵系统的设计方案。通过分析复合埋管式土壤源热泵地埋侧系统能效及经济性,肯定复合埋管式土壤源热泵系统的优势所在,并对复合埋管式换热器水力工况进行优化。最后通过实验验证地埋管换热器三维传热数值计算模型的正确性。首先基于天津市某办公建筑建立负荷计算模型,计算全年逐时建筑负荷,并选择合适的热泵机组,得到制冷和制热工况下机组的逐时出力负荷,根据建筑实际条件初步确定两种换热器承担负荷配比,进而制定符合该建筑负荷特性的复合埋管式土壤源热泵系统运行控制策略。分别建立水平埋管和垂直埋管三维传热温度场数学模型,通过数值计算分析水平埋管和垂直埋管换热器的换热性能,进而确定能够满足该建筑的制冷和制热需求的水平埋管换热器换热单元数及垂直埋管换热器钻井数,完成复合埋管换热器设计。负荷特性对复合埋管式换热器换热性能影响较大,在医院负荷特性及复合埋管换热器设计负荷配比等条件下,数值计算结果证明采用复合埋管式土壤源热泵系统并不合适。通过建立复合埋管式土壤源热泵系统能耗各组成部分模型,计算该办公建筑在制冷期和制热期的系统能耗,并得到夏季热泵机组COP与冷凝器进水温度的关系及冬季热泵机组COP与蒸发器进水温度的函数关系,进而得到在制冷和制热工况下热泵机组及复合埋管式土壤源热泵系统的逐时COP。采用费用年值作为指标,对不同承担负荷配比下复合埋管式土壤源热泵系统经济性进行分析。当垂直埋管换热器承担负荷配比逐渐增大时,系统费用年值基本呈现逐渐上升的趋势,但均低于独立垂直埋管换热器土壤源热泵系统费用年值。提出换热经济值的定义,以初步判断在满足换热要求条件下采用水平埋管换热器代替垂直埋管换热器承担负荷是否经济。结合复合埋管换热器的换热性能和经济性,总结得到复合埋管式土壤源热泵最佳承担负荷配比的方案选择方法。为减少数值换热计算时间,本文均采用水平埋管和垂直埋管换热器独立换热计算的方式评估换热器换热性能,且通过比较联合换热计算与独立换热计算结果可知,在该建筑负荷特性及水平和垂直埋管承担负荷配比条件下,独立换热计算结果与联合换热计算结果差异性较小,可视为独立换热计算对换热结果的影响并不大。提出了两种复合埋管式土壤源热泵系统地埋侧水泵的设置方法,通过水力计算,并利用环状管网水力计算与水力工况分析软件得到这两种方案在实际选取水泵参数条件下各埋管换热器环路流量,得到更有利于该办公建筑复合埋管式土壤源热泵系统水力工况的地埋侧水泵设置方案,为复合埋管式土壤源热泵系统中埋管换热器水力工况的优化提供了新思路。通过对独立埋管换热器进行实测,分别验证水平埋管和垂直埋管独立换热计算模型的正确性。再对复合埋管式土壤源热泵系统进行实测,并对比水平埋管换热器和垂直埋管换热器独立换热计算结果与联合换热计算结果,发现在实验室测试条件下,独立换热计算结果与实测结果有较大差别,而联合换热计算结果更准确,因此采用独立换热计算代替联合换热计算的方法必须在负荷特性与承担负荷配比匹配条件下使用。
[Abstract]:As a highly efficient and energy-saving renewable energy utilization technology, soil source heat pump has attracted much attention in recent years. At present, the performance of soil source heat pump system is mainly focused on the performance research of soil source heat pump system with horizontal or vertical pipe heat exchangers, and the source heat of soil source heat exchanger combined with horizontal and vertical buried pipes is used. The research results of the pump system are still less. In this paper, the soil source heat pump system, which is combined with the horizontal buried pipe and the vertical buried pipe, is called the compound buried pipe type soil source heat pump system and has been studied. Based on an office building in Tianjin, starting with the load load of the heat pump unit, it is preliminarily determined according to the actual conditions and economy of the building. Two kinds of pipe heat exchangers bear the load ratio, and then the operation control strategy of the composite buried pipe type soil source heat pump system aiming at the load characteristic of the office building is formulated. The three dimensional heat transfer model of the horizontal pipe heat exchanger and the vertical pipe heat exchanger is established respectively. A composite buried pipe type soil source heat pump system is designed. Through the analysis of the energy efficiency and economy of the buried pipe type soil source heat pump system, the advantages of the composite buried pipe type soil source heat pump system are affirmed and the hydraulic conditions of the compound pipe heat exchanger are optimized. Finally, the three-dimensional heat transfer of the buried pipe heat exchanger is verified by the experiment. The correctness of the numerical model. First, based on a load calculation model of an office building in Tianjin, the load of hourly building in the whole year is calculated, and a suitable heat pump unit is selected to get the time to hour force load of the unit under the conditions of refrigeration and heat production. According to the actual conditions of the building, the two kinds of heat exchangers are initially determined to bear the load ratio, and then the characters are formulated. The operation control strategy of the composite buried pipe type soil source heat pump system is combined with the load characteristic of the building. The mathematical model of the three-dimensional heat transfer temperature field of the horizontal and vertical buried pipes is set up respectively. The heat transfer performance of the horizontal and vertical buried pipe heat exchangers is analyzed by numerical calculation, and then the level of the cooling and heating demand of the building can be met. The number of heat exchanger and the number of vertical heat exchanger, the design of the compound pipe heat exchanger is completed. The load characteristics have great influence on the heat transfer performance of the composite pipe heat exchanger. Under the condition of the load characteristic of the hospital and the design load ratio of the compound pipe heat exchanger, the numerical calculation results prove that the compound buried pipe type soil source heat pump is used. The system is not suitable. Through the establishment of the model of the energy consumption of the composite buried pipe type soil source heat pump system, the system energy consumption of the office building during the cooling and heating period is calculated, and the relationship between the COP and the inlet temperature of the condenser in the summer heat pump unit and the function relationship between the COP and the inlet temperature of the steam generator in winter are obtained. The cost annual value of the heat pump unit and the compound buried pipe type soil source heat pump system under the refrigeration and heat production conditions is used as the index to analyze the economy of the compound pipe type soil source heat pump system under the different load ratio. When the load ratio of the vertical pipe heat exchanger is increased gradually, the annual value of the system cost is basically presented by the COP.. The rising trend is lower than the annual cost of the soil source heat pump system of the independent vertical buried pipe heat exchanger. The definition of the economic value of the heat exchange is put forward to determine whether the burden of the horizontal pipe heat exchanger to replace the vertical buried pipe heat exchanger under the requirement of heat exchange is preliminary. In order to reduce the calculation time of the numerical heat transfer, the heat exchange performance of the heat exchanger is evaluated by the method of independent heat transfer calculation of horizontal and vertical pipe heat exchangers, and the results of the combined heat transfer calculation and the independent heat transfer calculation are compared. Under the load ratio of the building load and the load ratio of horizontal and vertical buried pipes, the independent heat transfer calculation results have little difference with the combined heat transfer calculation results, which can be seen as the independent heat transfer calculation which has little influence on the heat exchange results. Two kinds of composite buried pipe type soil source heat pump system are put forward to set up the ground water pump. With the hydraulic calculation and the hydraulic analysis software of the annular pipe network, the two schemes are used to obtain the loop flow of the buried pipe heat exchangers under the actual parameters of the pump, and the scheme of the buried side water pump for the compound buried pipe type soil source heat pump system is obtained, which is used for the soil source heat of the composite buried pipe. A new idea is provided for the optimization of the hydraulic conditions of the buried pipe heat exchanger in the pump system. Through the measurement of the independent buried pipe heat exchanger, the correctness of the independent heat transfer calculation model of the horizontal and vertical buried pipes is verified respectively. The calculation results of the vertical heat transfer and the combined heat transfer calculation show that the calculated results of the independent heat transfer are quite different from the measured results in the laboratory test conditions, and the results of the combined heat transfer calculation are more accurate. Therefore, the method of replacing the combined heat transfer calculation by the independent heat transfer calculation must be made under the matching condition of the load characteristic and the load ratio. Use.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU83

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