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。     

CFD流体模型在双层换气幕墙传热分析中的应用

应用CFD计算流体动力学方法对双层换气幕墙的传热特性进行了全面的分析。在对双层换气幕墙的传热过程、传热方式进行了详细的阐述后,运用CFD紊流newk-ε模型对双层换气幕墙热通道的温度场、速度场、压力场进行了模拟计算,最终得出热通道空气层的对流换热系数和双层换气幕墙的整体传热系数。该对流换热系数作为双层换气幕墙传热分析的一个关键参数,对考察双层幕墙热工性能、经济性能有着重要作用。     

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。     

双层玻璃幕墙的传热特征研究

展示了一个通过计算流体动力学(CFD)计算机模拟获得双层玻璃幕墙传热特征的方法。通过CFD模拟计算的结果,拟合得到了双层玻璃幕墙系统和单层玻璃幕墙系统的室内得热与太阳辐射和室内外温差两个变量之间的线性近似公式。该关系表征了幕墙系统的传热特征:太阳得热系数和有效传热系数(或U值)。用该公式估算夏冬季透过幕墙的室外冷(热)负荷十分方便,工程实用性很高。     

双层幕墙窄腔、宽腔的设计及选型分析

本文通过对窄腔、宽腔双层幕墙的热通道、热工性能进行分析比较,确定双层幕墙的宽窄选型,从而设计出合理的幕墙系统。     

双层呼吸式幕墙技术在建筑上的应用实践

双层呼吸式幕墙是在单层幕墙的基础上创新发展起来的。该幕墙在欧美国家应用较多,近几年,国内也相继出现同类幕墙建筑。通过外层单元式幕墙、内层构件式幕墙、热通道、防火措施等方面的深化设计介绍,体现了双层呼吸式幕墙具有良好的节能效果。     

冬季工况下DSF不同运行模式的模拟与实验研究

介绍双层玻璃幕墙在冬季的2种运行模式——通风模式和封闭模式,建立基于能量平衡的动态类区域模型来模拟双层玻璃幕墙在冬季工况下的热性能。在长沙地区的DSF实验台进行实验研究,验证模型的准确性。用验证的模型分析计算两种模式下通过幕墙的室内得热量。结果表明,在长沙冬季双层玻璃幕墙一般使用封闭模式,但在太阳辐射较大的时刻使用通风模式更节能。     

外循环双层玻璃幕墙能耗模拟研究

幕墙系统在各类建筑中都应用广泛,是建筑围护结构中耗能最大的部分。提高建筑幕墙的性能是提高建筑节能效果的关键。以北京地区办公建筑为背景,对应用较多的外循环双层幕墙进行模拟。通过控制日照、设备、分区等因素,对整体式、箱体式、廊道式、竖井式4种类型双层幕墙进行能耗和二维传热模拟,并对节能效果评定,发现减少贯通式热桥能耗损失是提高节能效果的关键。因此,提高幕墙连接部分的隔热能力或者减少连接部分可以大幅度减少能耗。不同类型和规模的建筑需要根据幕墙的性能、建筑高度和安全性要求进行选择。     

太原南站大空间建筑双层表皮保温性能实测分析

大型客运站是典型的大空间、高能耗建筑,双层表皮围护结构在解决高能耗的问题上具有极大的潜力,然而其保温效果及影响因素在国内还缺少一定的实证研究来支撑和验证。以太原南站外表皮中的双层组合幕墙为研究对象,对其在冬季运行时的表皮内外温度等进行实测,并基于实测数据,对其进行保温性能分析。研究在寒冷气候特征下,双层表皮作为外墙围护结构的保温性能,验证双层表皮在寒冷地区大空间建筑的保温效果。     

三种封闭式双层幕墙的热工分析

通过太阳辐射热的追踪、传热学的三大基本定律的应用和能量平衡方程的建立,求解了封闭式商业立面、常见玻璃幕墙阴影盒和封闭式双层玻璃幕墙三个案例的腔体内表面温度和热流密度,界定了腔体内空气层的自然对流形式、温度分布规律和热流方向。通过数据分析和案例改变条件给出了吸收太阳辐射热的影响因素,腔体内温度的影响因素,和封闭式双层幕墙在没有有效的材料搭配时会导致双层幕墙的节能效果低于单层幕墙结论。提出了腔体内温度过高对幕墙使用功能可能造成的伤害,并给出了降低腔体内温度的可行方法。     

双层皮玻璃幕墙风口的确定

通过对武汉某建筑物呼吸式双层皮玻璃幕墙流场的模拟,分析了进、出风口位置与大小对热工性能的影响,最后,给出一些设计建议。     

重庆某双层皮外围护结构通风效果实测及分析

对某改造建筑的双层皮外围护结构间层通道内的冬、夏季空气温度和速度及内侧墙体壁面温度进行了实测,分析了该双层皮外围护结构在冬、夏季的通风效果,结合室内工作者在外围护结构改造前后对室内空气环境的舒适性感受,分析了该双层皮外围护结构设计上的一些问题,指出了该结构体系设计中的注意事项。     

Performance evaluation of a hybrid photovoltaic thermal double pass facade for space heating

This paper presents the performance evaluation of a hybrid photovoltaic thermal (Semi transparent PVT) double pass facade for space heating. The thermal model has been developed by using the energy balance equations of the proposed hybrid photovoltaic thermal double pass facade under quasi-steady state condition. Numerical computations have been carried out for the composite climate of New Delhi, India. An analysis has been carried out to calculate annual energy and exergy gain for the hybrid photovoltaic thermal double pass facade. On the basis of numerical results it has been observed that the annual thermal and electrical energy are 480.81 kWh and 469.87 kWh respectively. The yearly overall thermal energy generated by the system has been calculated as 1729.84 kWh. It is also observed that the room air temperature increases by 5-6 °C than the ambient air temperature for a typical winter day.     

外循环式双层玻璃幕墙的热工性能研究

本文建立了双层玻璃幕墙(DSF)的简化热工模型,并采用热阻网络图,对温度矩阵及DSF热工性能进行了编程求解。基于求解结果,分析了幕墙结构尺寸及玻璃组合对幕墙换热的影响。结果表明:夏季工况下玻璃的光学性能对DSF热工性能的影响最大;在DSF玻璃光学性能确定的条件下,窄通道DSF热通道宽度对室内得热量的影响显著,宽通道DSF遮阳百叶位置对室内得热量的影响较大。     

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.     

双层皮玻璃幕墙节能研究综述及探讨

从传热机理研究、与建筑运行模式结合的研究以及全寿命周期分析三方面总结和分析了当前国内外双层皮玻璃幕墙热工性能研究的方法和成果,认为应将双层皮玻璃幕墙的设计纳入建筑设计的全过程,在不同的阶段采用不同的设计方法和工具,以便得到性能优良的双层皮玻璃幕墙。     

上海地区双层垂直绿化办公建筑实测研究

本文通过实测,研究了夏季工况下双层垂直绿化对上海地区办公建筑热工环境的影响。实验结果表明,带有双层垂直绿化的办公室室内空气温度较普通房间平均降低了1.5℃,外墙外表面温度平均降低了1.3℃,双层垂直绿化可以有效改善上海地区办公建筑夏季热环境。本文通过实测探索了双层垂直绿化应用于办公建筑的节能潜力,并对双层垂直绿化植被选择、种植方式给出建议。     

Double versus single skin facades in hot arid areas

Double skin facades are defined as two layers of facade separated by an air gap, that varies in its depth creating a solar chimney effect where warm air rises by buoyancy. As a facade technology, its thermal and daylight performance is still under scientific scrutiny. The bulk of research on the performance of this facade configuration is carried out in moderate climates.     

Lichttechnisches und energetisches Verhalten von Fassaden moderner Verwaltungsbauten – Teil 1: Lichttechnisches Verhalten

Daylight and thermal energy performance of facades in office buildings, Part 1: Daylight performance. Regarding the impact on indoor illumination facade systems have to provide an appropriate visual indoor environment. In addition daylight penetrating the room through the facades should favourably influence the overall building energy balance. Daylight utilization can directly reduce energy consumption for electric lighting and can indirectly – due to the higher luminous efficacy of daylight compared to commonly used artificial lighting systems – reduce the thermal loads within the conditioned building spaces. In part 1 of this contribution the influence of different facade solutions on room illumination is systematically investigated by means of a parametric study of significant room, outdoor, environmental and climatic parameters for ten facade systems. The facade systems considered are conventional, permanently shaded, and light redirecting systems. The analysis of system performance is based on newly developed characteristics which allow the analysis and optimization of different facade systems under working conditions. Part 2 of the contribution shows the energetic interaction of the facade dependent internal loads by artificial lighting system and solar heat gains.