Responsive envelope tessellation and stochastic rotation of 4-fold penttiles

This paper reports on the design and control of a responsive envelope based on the rotation of tessellated components. The study investigates responsive and dynamic approaches for building facades and envelopes to regulate solar shading, light control, views and thermal gain within the building. It is well known that near real-time visual output from computational simulation can significantly impact the prediction of dynamic building-environment interactions and lead to the development of smart, adaptable, net zero energy buildings. To address these motivations, this paper reports the development of an experimental simulation of a responsive envelope based on using a 4-fold penttile scheme. The simulation is developed using a novel pentagonal approach involving component (tile) design, tessellation and control methods. The paper further elaborates on the geometry and control aspects of the facade subdivision and presents the results of applying this tessellation geometry to a building envelope shading study based on facade components with rotation. Finally, it tests the “responsiveness” to multiple performance metrics by applying a non-deterministic exploration method for the stochastic rotation of individual panels. The sophisticated evaluation of alternative envelope configurations for a set of performance criteria require a tighter computational coupling between modelling and control of dynamic geometry.     

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.     

The impacts of ventilation strategies and facade on indoor thermal environment for naturally ventilated residential buildings in Singapore

The impacts of various ventilation strategies and facade designs on indoor thermal environment for naturally ventilated residential buildings in Singapore are investigated in this study based on thermal comfort index. Four ventilation strategies, nighttime-only ventilation, daytime-only ventilation, full-day ventilation and no ventilation were evaluated for hot-humid climate according to the number of thermal discomfort hours in the whole typical year on the basis of a series of TAS simulations. Parametric studies of facade designs on orientations, window to wall ratios and shading devices were performed for two typical weeks by coupled simulations between building simulation ESP-r and CFD (FLUENT). The results indicate that full-day ventilation for indoor thermal comfort is better than the other three ventilation strategies. With various facade design studies, it was found that north- and south-facing facades can provide much comfortable indoor environment than east- and west-facing facades in Singapore. It is recommended that optimum window to wall ratio 0.24 can improve indoor thermal comfort for full-day ventilation and 600 mm horizontal shading devices are needed for each orientation in order to improve thermal comfort in further.     

A low environmental impact anidolic facade

The building of the Solar Energy Laboratory (LESO) of the Swiss Federal Institute of Technology of Lausanne was erected in 1981 to allow “in situ” testing of experimental solar facades. In 1998, the building was the object of a significant restoration and a new southern facade was designed and built following the principles of sustainable development. This article describes the principles that guided this work, and presents the results obtained with regard to energy consumption, flow of matter, daylight, comfort and, lastly, a detailed life cycle assessment analysis: the various environmental impacts related to the construction, exploitation and maintenance of the facade are presented and discussed.     

Solar control: A general evaluation method for facades with venetian blinds or other solar control systems

A general method for realistic performance evaluation of solar control properties of facades for facades with sun-shading or other solar control systems has been developed. It is particularly designed to be used for venetian blinds. It can be used used ‘stand-alone’ or within building simulation programs. The new method has proven to be of great practical value to planning teams of huge office buildings in Germany, Austria and Switzerland. The method is presented in detail in this paper. It can be used either ’stand-alone’ (without building simulation) for comparisons of different facade variants or within building simulation programs. Some parts of the proposed methodology could be used in standards (e.g. EN13363) or to improve the accuracy of building simulation programs which are currently on the market. Practical experience with the new methodology led to insights which are the basis for the design of two new products. These new products are compared with state of the art products in [T.E. Kuhn, Solar control: comparsion of two new systems with the state of the art on the basis of a new general evaluation method for facades with venetian blinds or other solar control systems, Energy and Buildings, in press] on the basis of the new methodology.     

Local vs. integrated control strategies for double-skin systems

This paper presents the follow-up in the development of occupant responsive optimal control for double-skin systems that was published previously in Park et al. [1]. The presented occupant responsive optimal control optimizes in real-time the performance of the facade in terms of energy, visual comfort (average daylight interior illuminance, uniformity, average window luminance, and outward visibility) and thermal comfort (Predicted Percentage Dissatisfied, PPD). In the aforementioned approach, the double-skin façade system was viewed as an ‘isolated’ system and hence treated as a local control problem, i.e., based purely on information about the state of the façade and its immediate environment. The paper extends the local control problem to an integrated control problem in which room environmental control and façade control are dealt with simultaneously. It was found that the local control leads to sub-optimality, albeit of moderate proportions.     

工业建筑的艺术化表达——广州市粮食储备加工中心项目设计

以广州市粮食储备加工中心项目为实例,通过对粮食仓储加工类工业建筑外立面处理方式的研究,探讨在工业建筑立面设计中强化企业形象的可能性,将企业形象通过艺术化的表达应用在工业建筑的立面设计中,并由此提出在工业建筑创作时应持的态度。     

Sonnenschutz: Eine generelle Bewertungsmethode – auch für zwischenliegende Systeme – und zwei neue Behänge

Sun control: General evaluation method (also suitable for integrated systems) and two new blind types. A general method for realistic performance evaluation of solar control properties of facades with sun‐shading or other solar control systems has been developed. It is particularly designed to be used for venetian blinds. It can be used ‘stand‐alone’ or within building simulation programs. The new method has proven to be of great practical value to planning teams of huge office buildings in Germany, Austria and Switzerland. The method is presented in detail in [4]. It can be used either ‘stand‐alone’ (without building simulation) for comparisons of different facade variants or within building simulation programs. In this publication the extension of the methodology for the case of facades with solar control systems between the panes of an insulating glazing unit (IGU) is presented. Some parts of the proposed methodology could be used in standards (e.g. EN 13363) or to improve the accuracy of building simulation programs which are currently on the market. Practical experience with the new methodology led to insights which are the basis for the design of two new products. These new products are compared with state of the art products in [5] on the basis of the new methodology. We are currently linking the new method with the building simulation program ESP‐r in a project which is funded by the Veluxstiftung.     

Modelling the service life of rendered facades using fuzzy systems

The knowledge of the service life and durability of building components is paramount to sustainable analysis and decision making since it allows a more rational management of the maintenance of building and provides data for life cycle analysis procedures. Nevertheless, predicting the service life of a building or its components is a complex process with which a number of variables are associated. The main difficulties associated with service life prediction are related to the complexity of the degradation phenomena and to the lack of understanding of degradation factors and mechanisms. This paper aims at establishing a model for the service life prediction of rendered facades using a Takagi–Sugeno fuzzy model. The models proposed include the variables that influence the degradation of rendered facades (render age, render type, building height, facade orientation, exposure to damp, and facade protection level). In this study, the degradation condition of 100 case studies located in Portugal is analyzed based only on in situ visual inspections. The proposed models are able to describe appropriately the degradation of rendered facades and to predict the service life of the sample analyzed.     

Wind-driven rain on the facade of a monumental tower: Numerical simulation,full-scale validation and sensitivity analysis

Wind-driven rain (WDR) is one of the most important moisture sources that affect the hygrothermal performance and the durability of building facades. The facades of the Dutch monumental building St. Hubertus show severe deterioration caused by WDR. Assessment of the amount and intensity of WDR falling onto the facades is necessary as input for numerical heat-air-moisture (HAM) transfer models to analyse the causes of the moisture problems and the impact of remedial measures. In this study, a numerical simulation method based on Computational Fluid Dynamics (CFD) is used to predict the amount of WDR impinging on the south-west facade of the tower of the building. The paper focuses on the numerical simulation results, the validation of these results and their sensitivity to two parameters: the level of geometrical detailing of the computational building model and the upstream terrain aerodynamic roughness length. Validation is performed by comparison of the numerical results with a dataset obtained from on-site WDR measurements. It is shown that the CFD simulations provide fairly good predictions of the amount of WDR impinging on the south-west facade of the tower, except for the lower part. It is also shown that the local effects of geometrical facade details are significant and can yield differences in WDR exposure up to 40%, while their effect at other positions is negligible. Finally, the sensitivity of WDR simulations to the upstream aerodynamic roughness length is discussed.     

温和气候区单层与双层玻璃幕墙节能评价

玻璃幕墙在现代建筑中应用广泛。玻璃幕墙设计不仅立足现代化的建筑外观,更要达到节能目的。一方面,太阳辐射能够透过玻璃幕墙进入室内,补偿建筑的采暖能耗,另一方面,大面积玻璃幕墙也可能带来室内过热问题。本文研究了两种幕墙系统的能源平衡问题,一种是单层双玻幕墙,另一种是双层通风玻璃幕墙,以实验测试为基础对其进行节能评价。     

Prediction of reflected solar dazzle from sloping facades

Glare or dazzle can occur when sunlight is reflected from a glazed facade. For vertical facades this problem usually occurs only when the sun is low in the sky; but some types of modern design incorporate sloping glazed facades which can, under certain circumstances, reflect unwanted high altitude sunlight into the eyes of motorists, pedestrians and people in nearby buildings. This paper presents, for the first time, a method which can be used at the design stage to calculate whether such solar dazzle will be reflected from a proposed building facade. From simple input data the times (if any) of year at which reflected dazzle could occur, and the total number of hours for which sunlight would in practice be reflected, can both be calculated.     

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.     

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.     

Building envelope regulations on thermal comfort in glass facade buildings and energy-saving potential for PMV-based comfort control

This paper presents an investigation of the effect of building envelope regulation on thermal comfort and on the energy-saving potential for PMV-based comfort control in glass facade buildings. Occurrences and severity of overheating, based on the PMV-PPD model contained in ISO 7730, were used for the thermal comfort assessment. Parametric study simulations for an actual building with a large glass facade were carried out to predict the changes in thermal comfort levels in a space due to different glazing types, depths of overhang and glazing areas, which are the key parameters of the building envelope regulation index, named ENVLOAD, in Taiwan. The result demonstrates that the ENVLOAD has significant effect on thermal comfort. Additionally, comparative simulations between PMV-based comfort control and conventional thermostatic control were performed to investigate the changes in the energy-saving potential of a thermal comfort-controlled space due to changes of its ENVLOAD. The results demonstrate that the energy-saving potential in a PMV-based controlled space increases with low ENVLOAD conditions.     

以哈尔滨为例探究建筑外立面形象塑造意义

简述了建筑外立面与建筑形象的含义,以哈尔滨的城市建筑为例,针对目前建筑外立面形象塑造的现状,分析了影响建筑外立面设计的因素,并对建筑外立面形象塑造的意义及其发展趋势作了研究,为建筑的装饰设计提供了理论依据。     

Computational fluid dynamics simulations of wind-driven rain on a mid-rise residential building with various types of facade details

Numerical studies of wind-driven rain (WDR), reporting detailed analysis of rain exposure on building facades, focus mainly on simplified building facades. However, small-scale facade details have a large impact on the rain exposure of a building, redistributing WDR locally. The present study reports results of computational fluid dynamics simulations with Eulerian multiphase (EM) model for WDR on a stand-alone mid-rise residential building. The influence of facade details, namely roof overhangs, balconies and window sills, is analysed. It is shown that even a very small surface detail, such as a window sill with a size of 0.10?m, can decrease catch ratio by up to 37% and droplet impact speed by up to 40%. Numerical simulations also show the practicality of the EM model for detailed analysis of WDR intensity on a complex building and its ability to be used as a design tool.     

Optimal operation of a south double-skin facade

There is an increasing demand for higher quality office buildings. Occupants and developers of office buildings ask for a healthy and stimulating working environment. Double-skin facades are appropriate when buildings are subject to great external noise and wind loads. A further area of application is in rehabilitation work, when existing facades cannot be renewed, or where this is not desirable. Double-skin facades have a special esthetic of their own, and this can be exploited architecturally to great advantage. However there are still relatively few buildings in which double-skin facades have actually been realized, and there is still too little experience of their behaviour in operation. In this matter, we choose to study a multistory double-skin facades behaviour. Simulations were realized with TAS software on the building proposed in the frame of the subtask A of the Task 27 (performance of solar facade components) of the International Energy Agency. Simulations were performed on the chosen building with and without double-skin facades. We decide to study eight types of days; and we analyze the double-skin facade behaviour for various operations. The thermal behaviours of the building with and without double-skin are compared. The study of these eight cases showed the importance of the dynamic use of the double-skin. The operation of this one must be obligatorily related to the climatic conditions as well external as interior and a bad operation of the double-skin could lead to catastrophic results.     

Solar control: A general method for modelling of solar gains through complex facades in building simulation programs

This paper describes a new general method for building simulation programs which is intended to be used for the modelling of complex facades. The term ‘complex facades’ is used to designate facades with venetian blinds, prismatic layers, light re-directing surfaces, etc. In all these cases, the facade properties have a complex angular dependence. In addition to this, such facades very often have non-airtight layers and/or imperfect components (e.g. non-ideal sharp edges, non-flat surfaces, …). Therefore building planners often had to neglect some of the innovative features and to use ‘work-arounds’ in order to approximate the properties of complex facades in building simulation programs. A well-defined methodology for these cases was missing. This paper presents such a general methodology.The main advantage of the new method is that it only uses measureable quantities of the transparent or translucent part of the facade as a whole. This is the main difference in comparison with state of the art modelling based on the characteristics of the individual subcomponents, which is often impossible due to non-existing heat- and/or light-transfer models within the complex facade.It is shown that the new method can significantly increase the accuracy of heating/cooling loads and room temperatures.     

双幕墙长矩形建筑风荷载特性的试验研究

以节能、生态为理念的双幕墙围护体系已逐步应用于高层办公建筑中。由于双幕墙之间存在通风廊道,因此对于双幕墙建筑有三个受风表面,即外层幕墙的内表面和外表面以及内幕墙的外表面,这使得风载取值变得复杂,目前也无规范可依。本文通过对杭州市某双幕墙办公楼的风洞试验研究,探讨了双幕墙建筑内、外层幕墙的风载取值问题;研究了门厅大跨挑篷风压分布特征,当风从侧面吹向挑篷时,挑篷上、下表面风载与普通屋盖挑篷相同,而当风从正面吹向挑篷时,挑篷上表面出现正风压,并对此现象进行了分析;文中针对该建筑物长宽比较大的特点,比较了大长宽比矩形建筑风载体型系数与规范给出的正方形建筑风载体型系数:当风沿建筑物长向流动时,采用规范给出的正方形建筑风载体型系数是可行的,当风沿建筑物进深方向流动时,其两侧及背风面的负压比正方形的大。