累计冷热负荷比对两种形式的土壤源热泵系统性能参数的影响研究

发布时间：2018-05-02 11:51

本文选题：土壤源热 + 泵系统累计冷热　；参考：《华中科技大学》2013年硕士论文

【摘要】：近年来，节能环保的地源热泵系统成为人们关注的焦点。夏热冬冷地区冷热负荷的不平均导致了土壤源热泵系统存在热积累，而带有辅助散热装置的土壤源热泵系统在理论上可有效的解决这一问题。目前，国内常用的两种系统形式是：地埋管-冷却塔混合式土壤源热泵系统和土壤源热泵-冷水机组联合运行系统。但实际工程中，由于设计、施工等原因，系统仍旧存在一定程度的热积累。并且，国内频频将地源热泵系统应用于大型公建工程中，这类建筑的“内区”冬季仍需供冷，建筑冬夏累计冷热负荷差更大。因此大型公共建筑冷热负荷的累计冷热负荷比对土壤源热泵系统的性能参数影响值得探究。本文选取武汉某一办公楼建筑为对象，利用DeST-C模拟建筑全年动态冷热负荷。以此办公楼为原型，通过扩大或缩小单层面积以及改变层数，得到大小不同的建筑面积和相应的累计冷热负荷比。为了研究的目的，这些累计冷热负荷比的间隔是相对均匀的。利用TRNSYS对不同累计冷热负荷比下两种系统进行了20年仿真模拟，分析各种累计冷热负荷比模型下土壤平均温度变化趋势和热泵系统（包括热泵机组、冷水机组、冷热源侧水泵和冷却塔）的能耗状况，比较单位能耗（系统获得每千瓦的冷量或热量所需电能）以获得系统的经济性评价。以土壤源热泵系统20年的土壤平均温度和单位能耗两项指标为依据，分析总结出以下结论：（1）对于地埋管-冷却塔混合式土壤源热泵系统，由于热积累效应，热泵系统随着累计冷热负荷比的增加，土壤平均温升更大，速度更快，热泵进口温度也越高，单位能耗增加，热泵系统运行费增加。（2）对于土壤源热泵-冷水机组联合运行系统，如按照冬夏承担峰值负荷相等的方法进行热泵系统设计，土壤热积累现象极其严重，建议按照冬夏累计排热量和取热量相等的方法进行设计。这种设计方法下，土壤热积累现象明显小于地埋管-冷却塔混合式土壤源热泵系统。（3）同样的累计冷热负荷比情况下，土壤源热泵-冷水机组联合运行系统与地埋管-冷却塔混合式土壤源热泵系统相比单位能耗较小，初投资较大。若综合考虑系统初投资和运行费的话，土壤源热泵-冷水机组联合运行系统获得每千瓦的冷量或热量花费较少。本文在分析累计冷热负荷比对两种土壤源热泵系统性能参数的影响的基础上，，给出了两种系统的经济性分析，为其进一步的推广应用提供一定的参考。
[Abstract]:In recent years, energy-saving and environmental-friendly ground-source heat pump system has become the focus of attention. The uneven heat and cold loads in hot summer and cold winter area lead to the existence of heat accumulation in the ground-source heat pump system, and the ground-source heat pump system with auxiliary heat dissipation device can effectively solve this problem in theory. At present, two kinds of systems are commonly used in our country: the hybrid ground source heat pump system with buried pipe and cooling tower and the combined operation system of ground source heat pump and water chillers. However, the system still has a certain degree of heat accumulation due to design, construction and other reasons in practical engineering. In addition, the ground-source heat pump system is frequently used in large-scale public construction projects in China. The "inner zone" of this kind of building still needs to be cooled in winter, and the accumulated cold and heat load difference in winter and summer is even greater. Therefore, the influence of accumulative cold and heat load ratio of large public buildings on the performance parameters of ground-source heat pump system is worth exploring. In this paper, an office building in Wuhan is selected as an object, and DeST-C is used to simulate the annual dynamic cooling and heat load. By enlarging or reducing the single-layer area and changing the number of floors, the different building area and the corresponding cumulative cold and heat load ratio can be obtained by using this office building as a prototype. For the purposes of the study, the intervals between these accumulative cold and heat load ratios are relatively uniform. Two kinds of systems with different accumulative cold and heat load ratios were simulated by TRNSYS for 20 years. The variation trend of soil average temperature and the heat pump system (including heat pump unit, chiller unit) were analyzed under various accumulative cold and heat load ratio models. The energy consumption of water pumps and cooling towers on the side of cold and heat sources is compared to the energy consumption per kilowatt, which is required by the system to obtain the economic evaluation of the system. Based on the two indexes of average soil temperature and unit energy consumption of the GSHP system for 20 years, the following conclusions are concluded: (1) for a ground-buried tube-cooling tower hybrid ground-source heat pump system, due to the effect of heat accumulation, with the increase of the accumulative ratio of cold and heat load, the average temperature of the ground temperature rises more rapidly, and the inlet temperature of the heat pump is also higher, and the unit energy consumption increases. The operating cost of heat pump system is increased. 2) for the combined operation system of ground-source heat pump and chiller, if the heat pump system is designed according to the method of equal peak load in winter and summer, the phenomenon of ground heat accumulation is extremely serious. It is suggested that the design should be carried out according to the equal method of summertime and summertime accumulative heat discharge. Under this design method, the phenomenon of soil heat accumulation is obviously smaller than that of hybrid ground source heat pump system with buried pipe and cooling tower. 3) under the same accumulative cold and heat load ratio, the combined operation system of ground-source heat pump and chillers is less energy consumption and larger initial investment than the hybrid ground-source heat pump system with buried tube-cooling tower. If the initial investment and operating cost of the system are taken into account, the combined operation system of ground-source heat pump and water chiller can achieve less cooling or heat cost per kilowatt. On the basis of analyzing the effect of accumulative cold and heat load ratio on the performance parameters of two kinds of ground-source heat pump systems, this paper gives the economic analysis of the two systems, which provides a certain reference for its further popularization and application.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU83

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