幕墙通风系统设计探讨

从幕墙通风系统的结构形式、热工性能等方面对内、外循环式幕墙通风系统进行了分析,并结合工程实例探讨了两种幕墙通风系统在工程中的应用.     

内置遮阳百叶外呼吸双层通风幕墙热工性能研究

对杭州市某建筑的外呼吸式双层通风幕墙进行了热工性能的模拟分析,依据JGJ／T151—2008,采用幕墙门窗热工性能计算软件对内外层幕墙的传热系数、遮阳系数以及可见光透射比等参数进行模拟计算,并计算冬季封闭及夏季通风状态下的传热系数．采用CFD技术对双层通风幕墙空腔内的速度场和温度场进行模拟分析。本研究成果直接指导了该项目双层幕墙的热工设计．且对类似工程具有很好的借鉴价值。     

浅谈外循环通风双层幕墙的设计

文章介绍了如何应用空气流动原理来设计外循环通风双层幕墙,以达到节能的目的,并提出相关的措施来保证幕墙性能。     

幕墙新品：双层幕墙

近年来一种节能环保的新型幕墙开始悄然流行,这种幕墙外层采用单层玻璃幕墙系统,层间采用特别的通风系统,内层采用中空玻璃幕墙系统,内外层幕墙之间的通道采用电动遮阳系统。双层幕墙分主动式内循环双层幕墙和外循环式双层幕墙。     

通风式双层玻璃幕墙的热工分析与探讨

本文通过浅显的理论分析对通风式双层幕墙的热工原理和计算公式进行推算和剖析,该种分析方法准确性较高,可用于通风式双层幕墙在实际工程的热工分析与能耗分析。笔者已经过多项实际工程验证,并且与国外先进的热工模拟软件进行比较,非常相近。     

自然通风型光伏双层皮幕墙光热传递特性研究

搭建了自然通风型光伏双层皮幕墙全尺寸实验房,采用了 4种自然通风循环模式,分别对外层皮透过率为100％及20％的双层皮幕墙热工参数进行实验测量.结果表明,4种自然通风循环模式的光伏双层皮幕墙结构均能够起到有效阻隔室外热量传递,并具备发电功能.透过率20％的光伏双层皮幕墙内外玻璃温差10℃以上,太阳得热系数0.1以下,U值2 W/(m2·K)左右;透过率100％的光伏双层皮幕墙内外玻璃温差5℃以下,太阳得热系数0.15以上,U值2.5 W/(m2·K)左右.外循环模式更好的带走空腔内热量,在降低室内得热方面为最优;贯穿型只加强了自然通风,不能有效的带走空腔内的热量;内外循环模式能够将室内热量带出室外,相比外循环模式可以形成由内到外的通风形式;内循环模式将空腔内的热量带入室内,形成了空调负荷,为不利的循环模式.本研究为自然通风型光伏双层皮幕墙在建筑光伏一体化中应用提供依据.     

浅谈双层玻璃幕墙及其风荷载特性

本文针对双层幕墙的风荷载特性,重点研究其内层幕墙的风荷载性能,并简单地介绍了双层幕墙的结构和形式,包括外循环式双层幕墙、内循环式双层幕墙、综合内外循环的双层幕墙,从而可以为进一步学习双层幕墙特性提供一种有效的思路。     

节能型外呼吸式双层通风幕墙热工性能分析及优化

采用Fluent软件对广州市某外呼吸式双层幕墙热通道内的温度场和速度场进行模拟分析.通过分析通道宽度、送风速度及风机安放位置等因素对综合传热系数的影响,研究了不同设计工况下该双层幕墙的热工性能,并相应提出双层幕墙的最优化设计.结果表明,在机械送风速度一定情况下,通道宽度对幕墙综合传热系数的影响很大,通道宽度越大,幕墙的热工性能越好；在通道宽度一定情况下,随着送风速度的增大,幕墙的综合传热系数逐渐减小并趋于稳定,最佳送风速度为1.5 m/s;不同的幕墙通道宽度下,风机的最佳安放位置与送风速度有关.     

夏热冬暖地区窄腔外呼吸双层玻璃幕墙关键技术

广东省中医院教学科研大楼工程是夏热冬暖地区首批大面积采用窄腔外呼吸式单元幕墙的工程,应用了很多新技术、新工艺,具有很高的研究价值。结合该工程,介绍了窄腔外呼吸式单元幕墙热工计算、双层玻璃幕墙节能分析、双层玻璃幕墙与单层中空玻璃幕墙节能效率对比、双层幕墙单元板块的吊装技术等一整套完整的施工工艺,最后介绍了窄腔外呼吸式幕墙通风设施改进和防火性能设计。     

被动式双层通风玻璃幕墙研究

阐述了被动式双层通风玻璃幕墙的构成特点及其传热机理,对通风幕墙的抗火性能进行了分析,并与普通中空幕墙作了保温、隔热性能比较,通过对双层通风幕墙经济价值的计算,从而确定了通风玻璃幕墙的可行性。     

Thermofluid-dynamic analysis of ventilated facades

Ventilated facades can be used in cases of renovation of existing buildings and new buildings to improve both the thermal performance of building, and external architectural skin. The energy advantage provided by the ventilated facades during the summer is the reduction of the heat load due to the combined effect of the shading of the external wall and the air flow caused by natural convection into the heated duct.The evaluation of ventilated facade performance requires a complete thermofluid-dynamic analysis of a ventilated air duct and an accurate knowledge of heat transfer coefficients, friction factors and thermo-physical properties of the materials.The Authors have used the computer code “Fluent” to investigate the thermal behaviour of three different typologies of ventilated facades.The aim of this research is to show an analytical method for design applications able to provide all the useful criteria for choosing the most suitable ventilated facades both in case of forced convection, due to the action of a fan, and natural convection due to stack effect.     

Investigation of the performance of a ventilated wall

The need for environmental friendly and energy efficient building design has stimulated the design of new facade technologies, including various configurations of double skin facades. This paper investigates the thermal performance of a ventilated wall, both for heating and cooling. A thermal analysis was carried out, paying special attention to the characterization of the heat convection resulting from the buoyancy-induced flow in the open air channel which proved to be a critical aspect of the ventilated wall's behaviour. An integrated thermal and air flow model for the entire system was developed. A model of the ventilated wall construction was developed with the ESP-r simulation program and checked against experimental data from a real-scale test cell facility.The thermal benefits of adding a radiant barrier layer were also investigated. The results showed that this layer was beneficial in terms of the energy performance of the construction. Also, the comparison between the experimental and simulation model results showed satisfactory levels of convergence with the exception of the night hours during the summer period. A sensitivity analysis was also undertaken in order to investigate the main factors and the extent of their effect on the temperature variation inside the ventilated facades.     

Strategies to improve the energy performance of multiple-skin facades

This paper describes how to optimize the energy performance of single-story multiple-skin facades (MSF) by changing the settings of the façades and HVAC-system according to the net energy demand of the building. The annual energy performance is analyzed for typical Belgian climatic conditions using a whole building simulation tool. Three MSF are scrutinised: a mechanically ventilated airflow window, a naturally ventilated double-skin façade and a mechanically ventilated supply window. Their performance is compared against the performance of two traditional facades: a traditional window with exterior and interior shading device. It is shown that both the heating and cooling demand may significantly be improved by implementing control strategies such as controlling the airflow rate and the recovery of air returning from the multiple-skin facades.     

玻璃光学属性对热通道玻璃幕墙系统节能性能的影响

本文研究了玻璃光学性能对热通道玻璃幕墙节能性能的影响,对两种不同结构的幕墙分别使用不同玻璃组合情况下的节能性能进行分析。结果表明,玻璃光学属性对热通道玻璃幕墙节能性能有很大的影响,一旦玻璃选用不合理,在夏季炎热天气时极易引起室内环境发生过热现象,并在恶化室内居住环境热舒适性的同时,带来大量的能源浪费。对比分析还发现,在夏季炎热地区,当外层使用吸热玻璃,内层使用由Low-E反射玻璃和普通玻璃组成的中空玻璃时,幕墙各项性能得到平衡,节能效果最好。     

Experimental and numerical analysis of heat transfer and airflow on an interactive building facade

The envelope of a building is mainly responsible for its energy demand. Different kinds of double skin facades (DSFs) are nowadays used as a building envelope to reduce the energy demand and improve aesthetical view of buildings. Although DSF are already extensively used, their thermal performance is not well understood. This study presents a decoupling method capable to evaluate thermal performances and analyze fluid phenomena in a DSF. The solar radiation effects were evaluated with an analytical model and computational fluid dynamics (CFD) simulations were used to evaluate complex flow and thermal effect on a commercial DSF. With the decoupling approach to account for the effects of solar radiation and flow, the numerical results obtained by the CFD approach agree well with the experimental data collected on a full scale test room with a ventilated DSF. The method can be used to establish a database to develop a tool for DSF design.     

带遮阳百叶热通道幕墙的热工数学模型

介绍了带遮阳百叶的热通道玻璃幕墙的简单数学模型。该幕墙由外侧单层玻璃幕墙和内侧中空玻璃幕墙组成热通道,通道中内置遮阳百叶以减少太阳能透射得热。在夏热地区,空气在通道中被太阳辐射加热,处于自然通风状态之下。列出了稳态条件下系统的热平衡方程,通过线性矩阵求解了太阳辐射和外界环境温度分别改变时,两个玻璃和通道内两个空气层及百叶的平均温度。计算模拟表明,内置遮阳百叶的热通道幕墙的内层中空玻璃的外表面温度较传统单层幕墙的表面温度有明显降低;与无遮阳百叶的热通道幕墙相比,室内透射得热量有很大减少,传热系数也比中空玻璃和无遮阳百叶的热通道幕墙有显著降低。     

双层幕墙冬季内循环送风的CFD气流及热工模拟

本文借助功能强大的CFD通用软件FLUENT,对广东省中医院的双层玻璃幕墙在冬季内循环运行的情况下进行了热工模拟,得到自然热气流及增强热气流两种工况下双层玻璃幕墙热通道内的速度场和温度场。在此基础上,得到出风口的空气流量、平均温度、平均风速等物理量,进而求出通风增热效率h及K值,最后对双层幕墙的冬季增热综合性能进行评估。     

Thermal behaviour of a ventilated double skin facade in hot arid climate

Modern Movement in architecture has resulted in a large number of high-rise buildings with glazed facades which increase the energy load of the buildings. To combat this phenomenon in colder climates, architects have turned to using double skin facades. These facades comprise of: a completely transparent external facade; an internal skin; and an air layer between the two. Research on the performance of double skin facades mostly considers cold and moderate climates. In addition, data collection is normally based on simulations, rather than actual field measurements. In this paper a building with double skin facade was monitored for 2 weeks in summer and 2 weeks in winter in the hot arid climate of Iran, in order to observe the behaviour of the facade both in hot and cold conditions. Additionally, simulations were performed on the case study building with and without double skin facade, to assess the effectiveness of the facade. The results revealed that the temperature difference between the outer skin, the inner skin and the cavity can significantly save heating energy in winter. To reduce the cooling loads in summer it is essential to introduce additional techniques such as night ventilation and installation of shading devices for the cavity.     

L形和一字形双层幕墙平均风压分布特性的试验研究

双层通风幕墙的抗风设计需考虑外层幕墙的内、外表面风压以及内层幕墙的外表面风压,其风荷载取值不同于普通单层幕墙,使得其风载取值变得复杂。通过多个不同截面形式的模型进行双层幕墙压力分布风洞试验研究。介绍风洞试验模型的设计及数据处理方法,着重分析一字形双层幕墙和L形双层幕墙的内外层幕墙的平均风压分布。试验结果表明:L形双层幕墙和一字形双层幕墙的平均风压分布有很大的不同。对于一字形双层幕墙,无论是正风压还是负风压,都主要作用在内幕墙上,外幕墙除拐角区域外所承担的风压很小。对于L形双层幕墙,其外幕墙的正风压要比内幕墙的风压大;负风压时,L形双层幕墙的短边区域是外幕墙所承担的风压大于内幕墙,其长边区域则是内幕墙所受的风压要大于外幕墙。     

双层皮玻璃幕墙技术分析

本文对欧洲应用较为广泛的双层皮玻璃幕墙技术的定义和发展过程做了概要介绍,就双层皮玻璃幕墙的分类和优缺点进行了总结,同时结合5例运用双层皮玻璃幕墙技术的欧洲设计实践进行了实例分析。