燃气锅炉辅助地源热泵复合系统优化设计及软件开发

发布时间：2018-07-29 20:04

【摘要】：在国家大力倡导可再生能源的前提下,地源热泵系统因其节能、高效的优点得到广泛的应用,但该技术在工程应用中也常常因为初投资大、地埋管施工困难以及吸放热量不平衡等因素阻碍了其发展。对于北方以热负荷为主导的建筑而言,燃气锅炉辅助地源热泵复合系统作为一种新的建筑节能技术,既可以有效地减少地埋管换热器的初投资,又可以解决地下热不平衡的问题。地埋管换热器的传热模型非常复杂,影响参数非常多,通过经验公式或者手工计算无法准确获得地埋管设计长度,因此使用专用设计软件对地埋管换热器的传热过程进行分析和模拟计算,并根据建筑负荷需求优化设计出合理的钻孔埋管长度已经成为地源热泵工程应用领域被普遍认可的设计计算方法。本文主要介绍了燃气锅炉辅助地源热泵复合系统的优化设计方法,并开发了专用的设计软件,包括软件界面,内部算法以及结果分析。该复合地源热泵系统开发软件是在山东建筑大学地源热泵研究所已开发的设计模拟软件“地热之星”的基础上,利用Visual Studio 2010开发平台,采用VC++语言编制的可视化设计模拟软件。复合能源供热系统设计的关键点之一就是要合理地确定每种供能系统承担的建筑负荷比例,尤其是要确保地下埋管全年冷热负荷基本平衡。因此本文首先建立了地埋管全年负荷分析方法,即根据建筑物全年累计负荷来确定地下热不平衡率,并根据工程允许的地下热不平衡率,求出该不平衡率下地埋管承担的最大建筑热负荷值以及热泵机组承担的累计负荷值。根据该负荷分析方法,基于地下热平衡理论提出对燃气锅炉辅助地源热泵复合系统的负荷控制法来控制燃气锅炉的启停。为了更好地分析复合系统的运行控制策略,本文还提出了采用分段时间控制的简单方法来控制燃气锅炉的启停。同时该软件在已有地埋管换热器传热模型的基础上,开发了复合地源热泵系统逐月设计计算方法和逐时模拟计算方法,利用该算法可以求出设计工况下地埋管长度,设计和模拟工况下土壤温度、热泵进出口温度、系统能耗、钻孔换热量等参数随时间变化的曲线和数据表格。本文还根据实际工程验证燃气锅炉辅助地源热泵复合系统的实用性以及开发的设计模拟软件的可靠性。根据系统实测数据与软件模拟数据对比,证明燃气锅炉辅助地源热泵复合系统中,燃气锅炉可以有效地起到调峰作用,减少地埋管设计长度,降低初投资,并且可以缓解地下热不平衡问题,提高机组效率。实测数据表明:开发的燃气锅炉辅助地源热泵复合系统设计模拟软件的计算结果是准确的,该软件可以对复合地源热泵系统长期运行工况进行模拟分析,为今后复合地源热泵系统的研究和应用提供理论支持和技术指导。
[Abstract]:The ground-source heat pump system has been widely used because of its advantages of energy saving and high efficiency under the premise of advocating renewable energy. However, the technology is often used in engineering because of the large initial investment. The difficulties of underground pipe construction and the imbalance of heat absorption and discharge hinder its development. As a new building energy saving technology, the gas-fired boiler assisted ground-source heat pump compound system can effectively reduce the initial investment of the ground buried tube heat exchanger for the buildings in the north, which is dominated by heat load. It can also solve the problem of underground thermal imbalance. The heat transfer model of ground buried tube heat exchanger is very complex and has a lot of influence parameters. The design length of underground tube can not be accurately obtained by empirical formula or manual calculation. Therefore, the heat transfer process of underground tube heat exchanger is analyzed and simulated by special design software. According to the requirement of building load, the reasonable length of buried pipe has become a widely accepted design method in the field of application of ground source heat pump (GSHP). This paper mainly introduces the optimization design method of the gas-fired boiler assisted ground-source heat pump compound system, and develops the special design software, including the software interface, the internal algorithm and the result analysis. The development software of the composite ground-source heat pump system is based on the design and simulation software "Geothermal Star", which has been developed by the Institute of Ground-Source Heat pump of Shandong Construction University, using Visual Studio 2010 development platform. Visual design simulation software developed by VC language. One of the key points in the design of compound energy heating system is to reasonably determine the proportion of building load to be borne by each energy supply system, especially to ensure the basic balance of the annual heat and cold load of underground buried pipes. Therefore, in this paper, the annual load analysis method of buried pipes is first established, that is, the underground thermal imbalance rate is determined according to the accumulated annual load of buildings, and according to the allowable underground thermal imbalance rate of the project. The maximum building heat load of the buried pipe and the accumulative load of the heat pump unit under the unbalanced rate are obtained. According to the load analysis method, based on the theory of underground heat balance, a load control method for gas-fired boiler assisted ground-source heat pump composite system is proposed to control the start and stop of gas-fired boiler. In order to better analyze the operation control strategy of the composite system, a simple method of piecewise time control is proposed to control the start and stop of the gas boiler. At the same time, based on the existing heat transfer model of the ground heat exchanger, the software developed the monthly design calculation method and the hourly simulation calculation method of the composite ground source heat pump system. The length of the buried pipe under the design condition can be obtained by using this algorithm. The curves and data tables of the variation of parameters such as ground temperature, inlet and outlet temperature of heat pump, energy consumption of system and heat exchange of borehole with time are designed and simulated. The practicability of the gas-fired boiler assisted ground-source heat pump compound system and the reliability of the simulation software developed are also verified in this paper. According to the comparison between the measured data of the system and the simulation data of software, it is proved that in the gas-fired boiler auxiliary ground-source heat pump compound system, the gas-fired boiler can effectively play the role of peak shaving, reduce the design length of the buried pipe and reduce the initial investment. And can alleviate the underground thermal imbalance problem, improve the efficiency of the unit. The measured data show that the simulation software is accurate, and the software can be used to simulate and analyze the long-term operating conditions of the composite ground-source heat pump system. To provide theoretical support and technical guidance for the future research and application of composite ground source heat pump system.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU83

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