【作者】 周娟；

【导师】 陈友明；

【作者基本信息】 湖南大学 ， 供热、供燃气、通风及空调工程， 2012， 博士

【摘要】 围护结构形式分不透明围护结构和半透明围护结构两大类。传统的多层墙体围护结构和现代新兴的通风式双层玻璃幕墙围护结构是目前最普遍的两大建筑围护结构代表。作为房间冷热负荷和建筑能耗的重要组成部分的建筑围护结构传热是随时间而变化的复杂过程。特别是我国夏热冬冷地区建筑围护结构更是处于强烈的非稳态传热过程。这使得人们通常在花费大量时间和精力后却难以准确快速实现非稳态的传热计算。因而面向当地气候特点，研究建筑围护结构的动态传热模拟方法，对于我国当前的建筑节能具有相当重要而紧迫的理论和工程意义。本文的研究工作分成两部分：第一部分研究以传统的多层墙体为代表的不透明建筑围护结构的动态传热模拟方法；第二部分研究以新兴的通风式双层玻璃幕墙为代表的半透明建筑围护结构在夏热冬冷气候条件下的动态传热模拟方法。本文的具体研究工作和结论如下：提出了对目前多层墙体围护结构非稳态传热的各种研究分析方法计算结果的动态验证方法。在采用不同的非稳态传热计算分析方法计算多层墙体围护结构的动态热特性基础数据时，存在着多种潜在因素将可能导致计算结果出现误差。本文基于线性系统动态模型的等价性与频率响应特性的原理，由z传递系数、反应系数及周期反应系数分别构建某不透明围护结构系统的几种动态模型。通过系统的伯德图，直观地观察和比较系统动态模型是否与其所描述的系统是一致或等价，进而验证了该系统的各种动态模型的正确性。利用这种动态验证方法对两类具有代表性的墙体结构进行实例计算验证。这种验证方法能在所关心的整个范围内检验结果的准确性，克服了传统的检验准则只在稳态条件下检验结果的单一性和片面性，同时又具有简单易行的特点。在第二部分研究中，对通风式双层玻璃幕墙围护结构进行适应于夏热冬冷地区气候条件下夏季动态传热模拟方法的研究及数值模拟。本文首先研究了带遮阳装置的半透明围护结构的动态变化的光学模型。考虑不同气候区域的影响，分别计算了北京和长沙逐时的室外太阳辐射强度、太阳高度角和壁面入射角。在此基础上基于虚拟百叶几何单元模型确定了遮阳百叶在不同太阳高度角下的直射辐射光学参数和散射辐射光学参数。然后基于界面能量平衡原理，建立了双层皮玻璃幕墙动态光学模型，分别计算北京和长沙地区各种结构形式的双层皮玻璃幕墙对太阳散射辐射和太阳直射辐射的逐时反射率、吸收系数和透过系数。计算结果表明同一种多层透过体系在不同地区的光学性能有着明显差异。逐时变化的光学模型可与双层皮玻璃幕墙系统的动态传热模拟过程相互耦合。通过综合控制体积模型与区域模型的优点，提出了相对简单却物理意义明确的类区域模型，分别建立了无遮阳通风式双层皮玻璃幕墙系统及有遮阳通风式双层皮玻璃幕墙系统的夏季动态传热模拟模型。将不同结构形式的双层皮玻璃幕墙系统划分成了数目比CFD模拟软件少得多的二维子区域，给出了各个子区域能量平衡偏微分方程组的数学表达式，并依据有限差分法原理编程实现了模型的数值求解。特别是对于有遮阳通风式双层皮玻璃幕墙系统，考虑了百叶遮阳的横向气流影响，基于幂律定律的原理建立了关于各个子区域之间流量平衡的非线性方程组，使空气腔内的气流运动与双层皮玻璃幕墙系统的动态传热过程相互耦合。最后利用本文提出的类区域模拟模型及所编程序，对带遮阳的内循环机械通风式双层皮玻璃幕墙系统夏季实验进行了仿真模拟，模拟结果表明本文类区域模型作为一种研究我国夏热冬冷地区气候条件下各类双层皮玻璃幕墙围护结构动态传热的模拟方法，具有较好的可靠性，且计算方法较简便，适合在工程设计中展开应用。更多还原

【Abstract】 Transient heat transfer through the building envelope is one of the principalcomponents of space cooling/heating loads and energy requirements. Especially forthe hot-summer and cold-winter zone in China, the conduction heat transfer throughbuilding envelope is highly erratic because of the bad weather conditions. It is still nota trivial exercise to predict the thermal performance of the fabric envelope.As there are two type of building envelope (opaque or transperant), the researchof dynamic heat transfer in this paper is also divided into two parts: the first part is forconventional wall constructions and the second part is for ventilated double-skinfacade (DSF) as they are now the types of envelopes mostly applied in commercialbuildings in China.In the first part of this paper, a method based on the equivalence of dynamicmodels for a linear system and the frequency characteristics of building transient heattransfer models are introduced for verification of the CTF coefficients and responsefactors over the whole frequency range.Various causes may lead to incorrect dynamic thermal behavior data used inbuilding simulation and dynamic space cooling/heating load calculation. Variousdynamic models of a linear system should be equivalent. The agreement between thefrequency characteristics of the models based on dynamic thermal behavior data andthe theoretical frequency characteristics of the construction is used to evaluate theircorrectness and reliability. The Bode diagrams for the dynamic models and theoreticalfrequency characteristics are visual aids to judge whether or not the dynamic thermalbehavior data is correct. Two examples have demonstrated the verification of dynamicthermal behavior data using the Bode diagrams and the percentage error. As thesteady-state conduction tests only checks the response at a single frequency, the workdescribed in this paper can tests the response over a range of frequencies. Furthermore,the method is both comprehensive and reasonably easy to implement.In the second part of this paper, models for simultaneous thermal, optical, andfluid flow processes are analyzed in turn to establish an improved zonal model tosimulate the complex dynamic thermal process occupied in the ventilated DSF in hotsummertime. As building energy consumption of buildings with DSF strictly depends on thesolar heat gain which differs with seasons and latitude location, the solar radiation,the sun-heights angle and the beam incident angle for the vertical skin in Changshaand Beijing are calculated respectively. These results show the importance of dynamicoptical model for the transient heat transfer process through the ventilated DSFThis paper also considered the spectral properties of the slab-type blinds whichshould change with different sun-height angle. A cell model of blinds is applied tocalculate the slab’s spectral properties for beam radiation and diffuse radiationrespectively. Then treat the blinds system as a transparent material whose extinctioncoefficient is given. Based on the radiation balance on the surface, the optical modelfor the multilayer transparent system is easily established to get its dynamic spectralproperties. The reflectivity, absorption and transmittance for direct and diffuse solarenergy of the whole DSF system are obtained respectively to calculate heat sources inglass panes and on opaque surfaces of shading devices. These heat sources aresubsequently implemented in the DSF simulation model.When simulating the thermal process in DSF system with or without slab-typeblind device in summertime, an improved zone model which is simple and explicit isprovided instead of those commonly used software which are very complex. Thisthermal model combines the control-volume method and zonal approach. Each layerof the DSF system is divided into many two-dimensional sub-zones. The mass andenergy conservation equations for each sub-zone are then given and calculated byfinite difference method. The Power Law Model (PLM) based on the relationshipbetween pressure difference and mass flow is applied to calculate the vertical air flowrate in the channel and the cross air flow rate through the slabs of the blinds. Thetemperatures and airflow results for each sub-zone are obtained at last.An existent summer experiment on the ventilated DSF system with slab-type blinddevice in the air channel is used to verify the introduced simulation model. The resultsshow that the improved zone model is reliable and simple which is suitable foranalyzing the dynamic heat transfer through the double-skin facade under the weatherconditions in the hot-summer and cold-winter zone in China.更多还原