土壤源热泵运行影响因素模拟与分析

发布时间：2018-12-16 07:08

【摘要】：地源热泵作为一项绿色能源技术,对土壤、地下水均无污染,系统较为简单,能效比更高可再生能源在今天成为了重要的供热、制冷技术。因此,大力开展地源热泵的技术研究与应用推广工作,特别是对地源热泵换热性能的影响因素的准确分析研究,可以对于不同的环境因素选择合适的地源热泵系统,对于减少我国能源消耗,减少对环境的污染都具有重要意义。地源不但是一种洁净能源,而且可循环再生,储备量丰富,对环境没有任何破坏。在今天环境问题和能源问题越来越受到大众的重视,几乎成为了现阶段社会发展的瓶颈,所以开发清洁能源和可再生能源是现今能源应用问题的重中之重,利用土壤源一方面可以减少环境的污染,另一方面因为土壤源储量巨大,可以形成新的能源供应方式,因此在未来具有广阔的开发价值。对于不论民用建筑还是商用建筑土壤源热泵的使用大多为间歇使用,研究间歇式运行的土壤源热泵不但可以节约能源,而且有利于土壤源热泵的换热效果,对其进行模拟和分析可以直观的了解土壤源热泵间歇式运行的土壤温度场,热媒温度变化,方便热泵的设计。土壤源热泵作为地源热泵的一种,相比水源热泵还没有广泛的应用,但是在近些年来,在政府的大力扶持下,土壤源热泵发展迅速,并且逐渐被人们接受,土壤源热泵的应用成几何增长。本文在已有的土壤源热泵研究的基础上,分析了在热泵实际运行中的各种影响因素。例如间歇运行、土壤中有渗水等等。本文针对土壤源热泵地下垂直U型埋管,建立了周围土壤的非稳态温度场的数学模型,利用FLUENT软件进行求解。通过对冬夏两季制冷工况的模拟,得到了热泵间歇运行埋管周围土壤温度场的变化规律,不同岩土含水量对地下换热器周围土壤温度场的影响,不同的埋管周围土壤渗流速度对地下换热器传热性能的影响,为土壤源热泵系统长期高效运行提供了理论参考。模拟结果表明,随着热泵的连续运行,埋管周围土壤温度场半径逐步扩大,长时间运行后,土壤热作用半径约为3.5m,继续运行变化不大,而热效率较低。而间歇运行不但可以节约在不需要时的能源浪费,而且可以使土壤温度回归,提高换热效率。本文根据既有建筑群的土壤源热泵的实际应用,对比了间歇运行与常规的连续运行的换热效率,为实际的地源热泵工程作为理论依据。
[Abstract]:As a green energy technology, ground-source heat pump has no pollution to soil and groundwater. The system is simple and the energy efficiency ratio is higher. The renewable energy has become an important heating and refrigeration technology today. Therefore, the research and application of ground-source heat pump technology, especially the accurate analysis of the factors affecting the heat transfer performance of ground-source heat pump, can select suitable ground source heat pump system for different environmental factors. It is of great significance to reduce energy consumption and environmental pollution in China. Not only a clean source of energy, but also renewable, abundant reserves, no damage to the environment. Nowadays, more and more attention has been paid to environmental and energy problems, which have almost become the bottleneck of social development. Therefore, the development of clean and renewable energy is the most important issue in energy application nowadays. On the one hand, the use of soil sources can reduce environmental pollution, on the other hand, because of the huge reserves of soil sources, a new mode of energy supply can be formed, so it has broad development value in the future. For the intermittent use of ground-source heat pump in both civil and commercial buildings, the study of intermittent ground-source heat pump can not only save energy, but also benefit the heat transfer effect of ground-source heat pump. Simulation and analysis of the ground source heat pump can intuitively understand the ground temperature field of intermittent operation, heat medium temperature change, and facilitate the design of the heat pump. Ground-source heat pump (GSHP) as a kind of ground-source heat pump has not been widely used compared with water-source heat pump. However, in recent years, with the support of the government, ground-source heat pump has developed rapidly and gradually accepted by people. The application of ground source heat pump becomes geometric growth. On the basis of the existing research on ground source heat pump, this paper analyzes the influence factors in the actual operation of the heat pump. For example, intermittent operation, soil seepage and so on. In this paper, a mathematical model of the unsteady temperature field of the surrounding soil is established for the underground vertical U-shaped buried pipe of ground-source heat pump. The model is solved by FLUENT software. Through the simulation of the cooling conditions in winter and summer, the variation law of soil temperature field around the buried pipe in intermittent operation of heat pump is obtained, and the influence of different rock and soil moisture content on the soil temperature field around the underground heat exchanger is obtained. The influence of different soil seepage velocities around buried pipes on the heat transfer performance of underground heat exchangers provides a theoretical reference for the long-term efficient operation of ground-source heat pump systems. The simulation results show that with the continuous operation of the heat pump, the radius of the soil temperature field around the buried pipe expands gradually. After long time operation, the soil thermal action radius is about 3.5 m, and the continuous operation has little change, but the thermal efficiency is low. Intermittent operation can not only save energy waste when not needed, but also make soil temperature return and improve heat transfer efficiency. According to the practical application of ground source heat pump in existing buildings, this paper compares the heat transfer efficiency between intermittent operation and conventional continuous operation, which is the theoretical basis for the actual ground source heat pump engineering.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU831

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