新建建筑围护结构热湿耦合动态特性试验及数值研究

发布时间：2018-03-25 19:57

本文选题：建筑节能　切入点：新建建筑围护结构　出处：《长安大学》2016年硕士论文

【摘要】：随着能源问题的不断突出、建筑能耗占社会总能耗比重的不断增长,建筑节能成为世界各国关注的热点问题。目前我国建筑节能措施主要考虑的是围护结构传热量对建筑能耗的影响,常常用传热系数的大小作为判断围护结构是否达到节能要求的主要标准,其中并没有考虑湿分的影响。然而由于建筑围护结构材料多为多孔介质,其在建成初期孔隙中极易存在湿分,墙体内部热量传递与湿分传输相互影响,具有强耦合性。含湿量不同时其传热方式不同,材料的导热系数也会随之发生变化。因此研究建筑围护结构热湿耦合传输过程十分必要,它对围护结构的热工性能、建筑能耗及对建筑物本身都有着重大的影响。本论文针对新建建筑的围护结构进行热湿耦合动态特性研究。采用原位试验与数值模拟相结合的方法,通过试验和数值计算结果分析,研究了西安市新建建筑外围护结构温度、体积含湿量随时间的变化情况,以及湿度变化过程中的有效传热系数的大小变化。在原位场地搭建了试验独立房屋,在其内部安装了热、湿检测系统及热流计系统,跟踪检测围护结构的温、湿度,定期检测其传热系数,并实时检测了该原位场地周围气候参数。选取可靠的测试方法对围护结构材料的热物性参数进行了实验室标定。通过试验得到了大量的有价值的试验数据。在此基础上,以实验测定结果及原位场地气候参数作为数学模型建立的基础条件,运用CHAMPS软件建立了墙体热、湿耦合动态分析计算模型,并应用建立好的墙体模型进行了1~2年的模拟计算。通过原位试验和数值模拟计算得到结论,墙体温度的传递具有衰减性和滞后性;新建房屋自建成至竣工后264天,各围护结构体积含湿量在自然条件下逐渐减少,不同朝向的同类墙体以及不同类型墙体,其体积含湿量下降率有所不同,多孔砖墙加气混凝土墙钢筋混凝土墙体;同种类型北向墙体湿度下降率大于东向墙体。各类保温墙体的传热系数由于保温层受潮先增加然后呈逐渐下降趋势,且实际传热系数始终高于干燥状态下的理论计算值。利用CHAMPS软件对该房屋钢筋混凝土北墙2年预测计算后发现,该新建建筑围护结构体积含湿量的变化是一个复杂的、反复的周期性过程,呈先下降后上升的变化规律;2年后该墙体的有效传热系数分别减少为理论传热系数的1.12倍、1.21倍。本课题的研究,为建筑围护结构保温性能的正确评价提供了帮助。
[Abstract]:As the energy problem becomes more and more prominent, the proportion of building energy consumption in the total energy consumption of society is increasing. Building energy conservation has become a hot issue all over the world. At present, the influence of heat transfer of envelope structure on building energy consumption is the main consideration of building energy saving measures in our country. The magnitude of heat transfer coefficient is often used as the main criterion to judge whether the envelope structure meets the requirements of energy saving, and the influence of moisture content is not considered. However, the materials of building envelope structure are mostly porous media. It is easy to have wet fractionation in the pore in the initial stage of its completion. The heat transfer and moisture transfer inside the wall have mutual influence, and have strong coupling property. The heat transfer modes are different with different moisture content at the same time. Therefore, it is necessary to study the thermal-moisture coupling transmission process of the building envelope structure, which is of great importance to the thermal performance of the enclosure structure. The energy consumption of the building has a great influence on the building itself. In this paper, the thermal-moisture coupling dynamic characteristics of the new building envelope are studied. The method of in-situ test and numerical simulation is adopted. Based on the analysis of experimental and numerical results, the temperature and volume moisture content of the surrounding structure of newly built buildings in Xi'an are studied with time. As well as the change of effective heat transfer coefficient in the process of humidity change. A test independent house was built in the in-situ site, and a heat and humidity detection system and a heat flow meter system were installed inside the building to track and detect the temperature and humidity of the envelope structure. The heat transfer coefficient is measured regularly, The surrounding climatic parameters of the in-situ site were measured in real time. The thermal physical parameters of the enclosure structure materials were calibrated by a reliable test method. A large number of valuable experimental data were obtained through the experiments. On the basis of this, a large number of valuable experimental data were obtained. Based on the experimental results and in situ site climatic parameters as the basic condition of mathematical model, the dynamic analysis and calculation model of wall thermal and wet coupling is established by using CHAMPS software. The results of in-situ test and numerical simulation show that the transfer of wall temperature is attenuated and delayed, and the new building is built from completion to 264 days after completion. The volume moisture content of each retaining structure decreases gradually under the natural condition. The volume moisture content of the similar wall with different orientation and different types of wall is different, and the volume moisture content of porous brick wall is different. The reinforced concrete wall of aerated concrete wall of porous brick wall is different. The decrease rate of humidity of the same type of north wall is greater than that of the east wall. The heat transfer coefficient of all kinds of insulation wall increases first and then decreases gradually because of the moisture of the insulation layer. And the actual heat transfer coefficient is always higher than the theoretical calculation value under the dry state. After 2 years' prediction calculation of the reinforced concrete north wall of the building by using CHAMPS software, it is found that the change of the volume moisture content of the new building envelope structure is complicated. After two years, the effective heat transfer coefficient of the wall is reduced to 1.12 times and 1.21 times of the theoretical heat transfer coefficient respectively. It is helpful for the correct evaluation of thermal insulation performance of building enclosure.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU111.4

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