【作者】 高亚南；

【导师】 李永安；

【作者基本信息】 山东建筑大学 ， 供热、供燃气、通风及空调工程， 2010， 硕士

【摘要】 针对普通空气源热泵冬季制热量衰减,夏天制冷量减少这一难题,同时为了克服传统地道降温工程中送风霉味重,室内空气品质差等缺点,本课题主要研究了将地下人防工程中的自然能源作为热泵空调系统的冷热源。地道大多在地下10米左右,由于地面温度波衰减和延迟的作用,相对于室外温度而言,冬季空气温度高,夏季空气温度低。在实际应用中,由于基于地道风的空气源热泵系统室外换热条件的改善,热泵性能系数COP值可以得到较大提高,这种方法不仅具有明显的节能效果,而且也是对我国丰富的地道资源进行开发利用。从保护大气环境、减少二氧化碳排放、可再生能源利用的角度来说,这不仅对我国现阶段有巨大的利用价值,对于将来仍具有实际意义。本课题首先讨论了地层土壤的能量来源,对热物性参数对土壤温度的影响进行了分析,并指出了地层土壤温度波的变化规律。建立了地层土壤内部温度的计算模型,得出了在地表面温度为简谐波变化时,地层土壤内部的温度计算公式。并根据该计算公式,分析了地层土壤内部温度波的变化特性。地层土壤温度波相对于地面温度波的衰减和延迟性为基于地道风的空气源热泵系统的应用提供了先决条件。其次,本文阐述了冬季基于地道风的空气源热泵系统中地道内空气与地道壁体传热过程的基本原理。根据空气与地道壁面传热过程的特点,对室外空气流经地道的非稳态耦合传热过程进行了分析,采用整场求解法对室外空气流经地道的耦合传热过程建立了统一的数学模型。借助CFD软件建立了符合实际几何形状和传热流动状况的地道内空气与土壤换热的三维数学模型。此外,本文还利用该模型对济南地区的某人防工程进行了数值计算,将实测值与模拟计算结果进行了对比,验证了该模型的准确性。通过对不同工况下的地道风进行数值模拟,本文对冬季影响空气与地道壁面之间传热过程的各项因素进行了对比分析,发现地道长度、地道埋深、空气流速、地道当量直径、不同进风温度等均对空气与地道换热过程有重要影响。引入了地道加热效率的概念,探讨了地道长度、地道内风速、地道埋深以及地道结构尺寸对地道加热效率的影响程度。在研究的基础上,给出了系统设计时,地道各参数的最佳设计范围,可供工程技术人员参考。最后,在国家级制冷产品性能检测室对基于地道风的空气源热泵机组进行了冬季性能测试,并与普通空气源热泵进行了对比。实验结果表明,基于地道风的空气源热泵系统在冬季运行时其制热量、性能系数与普通空气源热泵相比都有显著的提高,而且室外空气温度越低,该系统的增幅就越明显。尤其在温度极低的情况下,该系统的应用优势更加显著。此外,本文的研究结果表明：基于地道风的空气源热泵系统在冬季运行时不存在结霜问题,机组可以稳定可靠地运行,这样就节省了传统空气源热泵的除霜能耗。本课题的研究结果对基于地道风的空气源热泵系统的优化设计及高效运行具有较好的指导意义。本课题是住房和城乡建设部科技计划项目“基于地道风的空气源热泵”(课题编号：05-K3-13)的子课题。更多还原

【Abstract】 The heating capacity of the air source heat pump decrease sharply as the outdoor temperature falls in winter; the cooling capacity also decrease as the outdoor temperature raise in summer. And the traditional tunnel ventilation system supplied air of poor smell influencing indoor air quality. In order to overcome the problem of air source heat pump and take full advantage of the heat storage of the soil, this paper proposes a new air source heat pump system in which the tunnel is used to temper the ambient air, which is then used for heat exchange with a heat pump.Tunnel air temperature, at a depth of about 10 m or more, stays fairly constant throughout the year, and is approximately equal to the average annual ambient air temperature. In this heat pump system, coefficient of performance of the heat pump is always high because the temperature of underground tunnel air in summer is lower than that of atmosphere air, whereas that of underground tunnel air in winter is higher than that of atmosphere air. This system not only has obvious energy saving effect, but also makes full re-use of abundant underground tunnel resources in our country. From protecting the atmospheric environment and renewable energy utilization point of view, the study of air source heat pump based on the underground tunnel air is of great significance to low the energy consumption of building and protect the environment.Firstly, energy source of soil was discussed. The change law of soil temperature and the effect which has an impact on soil temperature caused by thermo-physical parameters are analyzed through the subject. The mathematic model of soil temperature is established. Based on the mathematic model, we can get the formula of soil temperature when the ground temperature varies harmonically. According to this formula, the characteristics of soil temperature are discussed. The attenuation and delay action of soil temperature offer the air source heat pump system which uses the air of underground air tunnel as the heat source precondition for its practical application.Secondly, the heat exchanging process that outdoor air flow through underground tunnel analyzed. On the basis of the characteristics of heat transmitting process in continuous ventilating tunnel, the unsteady coupled heat transfer between air and the tunnel walls are discussed. A mathematical model of unstable coupled heat transmitting process under changeable conditions is established using whole-field method. Subsequently, numerical simulations about the model of unsteady-state conjugated heat transfer with three-dimensional between airflow and tunnel is carried out with CFD software. By comparing measured tunnel data in Jinan to the numerical results, we can find that the numerical results of the mathematical model are in agreement with the measured ones, and its computational accuracy can satisfy the demand of practical engineer.According to the calculation results under different working conditions, we find that length of the tunnel, the buried depth of tunnel and velocity of air in the tunnel, inlet air temperature, equivalent diameter of the tunnel, and material of the tunnel all have big effects on the heat transfer process in tunnel. In this paper, concept "tunnel heating efficiency" is introduced. The amount of heat-exchanged between the air and the tunnel is influenced by the parameters like:length of the tunnel, velocity of air in the tunnel, the buried depth of tunnel and equivalent diameter of the tunnel. How these factors influence the tunnel heating efficiency are also analyzed. Based all the reaserches, the optimal scope of design about various parameters are illustrated. These advices could provide academic guidance to the system engineer designer.At last, experimental research of this system performance in winter is also carried out in laboratory located in Weifang. The calculated results show that air source heat pump based on the underground tunnel air, as compared to the heat pump without using the tunnel air as heat source, can not only raise heat capacity but also increase the heat pump coefficient of performance especially in the lowest temperature. In addition, air source heat pump based on the underground tunnel air can run stablely and reliablely without frosting in winter by theoretical analysis. The study of air source heat pump based on the underground tunnel air provides instructive and meaningful guidance to the optimization and efficient operation of system.This subject is a sub subject of scientific research project in the Ministry of Construction of China, which is "The air source heat pump based on the underground tunnel air" (Number05-K3-13).更多还原