DYNAMIC FACADES AND SMART TECHNOLOGIES FOR BUILDING ENVELOPE REQUALIFICATION by Alessandro Premier

Cover: S.Casarini, I.Luigabue, G.Magli

I nternational Academic Journal

New technologies and tools for built environment comunication and valorization edited by Katia Gasparini

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ISBN 978-88-96370-10-0 ISSN 2281-2210

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Knemesi Publisher www.knemesi.com Screencity_I.A.J.

issue 01 November 2012 ISSN 2281-2210 ISBN 9788896370100 Annual Academic Journal

SCREENCITY STAFF

ADVISORY BOARD

Directors Simone Arcagni Katia Gasparini

Giandomenico Amendola Simone Arcagni Pierre Auboiron Simon Biggs Roberto Bolici Massimo Canevacci Francesco Casetti Derrick De Kerchove Ruggero Eugeni Katia Gasparini Laurent Jullier Salvatore Iaconesi Giulio Lughi Lev Manovich Rossella Maspoli Scott McQuire Roy Menarini Francesco Monico Mario Ricciardi Giuseppe Richeri Mark Shepard Oliver Schürer Mirjam Struppek Christian Uva Vito Zagarrio Pietro Zennaro

Editor -in-chief Francesco Carcano Editorial board Simone Arcagni Katia Gasparini Giulio Lughi Rossella Maspoli Roy Menarini Pietro Zennaro Editorial staff Veronica Brustolon Roberta De Monte Miriam De Rosa Lorenzo Gerbi Chiara Gregoris Mirko Lino Anna Martini Eleonora Nicoletti Matteo Pedrotti Alessandro Premier Eleonora Salvalaio Editorial Coordination Serena Perrone Graphic Design Roberta De Monte

Suplement of “Aria” journal Logged in Tribunale di Milano n.465 07 giugno 2005 Publisher Circom società cooperativa via Cartesio 2 – 20124 Milano Knemesi Publisher Strada dei Monti 6 , 37124 Verona contact: editors@screen-city.net www.screen-city.net © Knemesi Publisher all rights of reproduction and translation of published articles are reserved print ATENA.NET Srl , Grisignano (VI)

The monography is the outcome of a International Seminars and Workshop “MEDIA-ENVIRONMENT, New technologies and tools for the communication and valorisation of the built environment “, conducted at the Politecnico di Milano, in the Mantua Regional Campus, and with Università Iuav di Venezia by the “Colour and light in architecture” Research Unit. It was financed with funds of the Iuav Department of Research of Università Iuav di Venezia, year 2011-2012.

The volume contains essays by some academics, researchers, selfemployed professionals and specialised technicians coming from different areas at national and international level and with a specific cultural, technical and scientific background. The series of seminars also included a planning workshop to which 260 students, enrolled in the undergraduate and postgraduate degree courses of Università Iuav di Venezia and the Mantua Campus of the Politecnico di Milano respectively, registered and participated in.

Planning and organization of the series of seminars and workshops Scientific direction

Prof.ssa Elena Mussinelli Dott. Katia Gasparini

International Advisory board

Fabrizio Schiaffonati Elena Mussinelli Pietro Zennaro Andrea Tartaglia Matteo Gambaro Katia Gasparini Kathrin Moore Pierre Auboiron Oliver Schürer

Coordination Tutors

Alessandro Premier , Amina Dehò Veronica Brustolon, Roberta De Monte, Chiara Gregoris, Anna Martini, Barbara Massa, Matteo Pedrotti, Eleonora Salvalaio

No part permission of this book may be used or reproduced in any manner without written permission from the publisher, except in the context of review. Unless specified, images and photos are the authors of the individual articles. For citations, photos and drawings belonging to the owned by third parties included in this opera, the authors of the articles are available to eligible not been able to find as well as for any unintentional omissions and /or errors of attribution in the references. Errors or omissions will be correct in subsequent editions.

I nternational Academic Journal

screencity

New technologies and tools for built environment comunication and valorization edited by katia Gasparini

Media Environment

CONTENTS 09

Dynamic façades and smart technologies for building envelope requalification Alessandro Premier

Introduction: dynamic façades in the building requalification Façade is the most strategic part in a requalification plan because it is the most visible part of the building (Zennaro, 2009). This leads to an improvement of environmental and appearance performances. The façade also exchanges energy with the external environment: this increases energy performance. The façade protects structures and interiors of the building and this contributes to the extension of the life of the building (Zennaro, Gasparini, Premier, 2012). If we consider architecture till the beginning of the Twentieth Century we may say that the façades of the traditional buildings are mostly static. On the contrary, in the contemporary environment the architectural envelope seems to be mostly dynamic (Gasparini, 2009). What might be the reasons for this change? First of all we have to say that the contemporary building must adapt to the continuous changing of the external environmental conditions. This entails the need for precise control of lighting and humidity performances of the building itself. The second reason is related to communication. Architectural surfaces have always been a support for communication. Now we talk about the expression of the technological elements. This question has emerged strongly since the beginning of the high-tech architecture. From a regulatory point of view this question is called “performance of

appearance” (see the Italian standard UNI 8290-3). However, all this features are strongly related to the success of the translucent and transparent surfaces in modern and contemporary architecture. Within this context mobile devices for sun shading play a very important role. According to NBN EN 12216:2002 they can be classified into: awnings, shutters and sunscreens (Premier A., 2012). These devices can be realized with traditional or innovative materials. Although the distinction between traditional and innovative materials is rather complex, we can say that we are using materials ranging from wood or ceramics towards composite materials and even smart materials. As we already said, the main feature of dynamic façades is a constant adaptability to environmental external conditions. We can distinguish dynamic façades made of traditional or innovative materials and dynamic façades built with smart materials and technologies. Dynamic façades built with traditional or innovative materials are implemented with automated control systems (sensor-controller-actuator) and they are built with materials on which we have near complete control. Dynamic façades built with smart materials and technologies independently respond to external stimuli (eg. temperature variations). They have been developed to consume very little energy or being self-sustaining (eg. photovoltaic cells). Smart materials such as dielectric elastomers, photomecha-

nical materials etc. are new materials of which we are testing the potentialities and new applications. Within this framework we need to clarify one thing: sun shading devices shall be placed on the outside of the glass envelope as if they were placed in the interiors their performance would be drastically reduced. A good alternative is to place the shading system within a double skin façade or within a triple glazing frame. Dynamic façades with traditional and innovative materials: the architectural design A dynamic façade can be realized with mobile panels of various shapes, built with different materials. Widespread is the use of perforated metal panels, usually with a simple shape, often rectangular. They are placed in front of the glass surfaces to form the outer skin of the building. Their movement is assured by electromechanical systems located within the support structure of the façade. A very effective example of this kind of façade is represented by the Kiefer Technic Showroom in Bad Gleichenberg (Austria). The building was designed in 2007 by the Austrian firm Ernst Giselbrech and Partner. It is placed in front of an existing factory and its main façade is the most important part of the building. This façade changes continuously: each day, each hour it shows a new face because of the movement of the white aluminium perforated panels. The architects have also designed a dedicated choreography that allows the building to become once a chess board, once again a big eye or a mouth, and so on. Not just a sun shading system but also an expressive way to communicate through the façade. Another example is the recovery of the former tobacco factory in Rome (2009). The building has been renewed by

the application of a new outer skin made of panels covered with stainless steel mesh. Some of these panels open and close as in the previous case. At night the building glows green, red and blue. Some interesting façade systems have been proposed in 2010 by ABI (Adaptive Building Initiative), a joint venture between Hobermann Associates from New York and Buro Happold (UK). They are based on the use of overlapped layers flowing on each other. The first one is called Tassellate™. It is a self-contained, framed screen whose perforated pattern can continually shift. This creates a dynamic architectural element that regulates light and solar gain, ventilation and airflow, privacy, and views. The system consists of a series of stacked panels that can be constructed of various metals or plastics. As the layers overlap, the result is visual display of patterns aligning and then diverging into a light-diffusing mesh. You may find an application of this system in the Simons Center for Geometry & Physics of the State University of New York at Stony Brook, Long Island. The other one is called Adaptive Fritting™. It is an integrated glass unit with a custom moveable graphic pattern that can modulate its transparency to control transmitted light, solar gain, privacy, and views. This performance is achieved by shifting a series of fritted glass layers so that the graphic pattern alternately aligns and diverges (www.adaptivebuildings.com). Another effective example concentrates mainly on the design of the sunscreen system. It is the dynamic envelope of Abu Dhabi Investment Council Headquarters designed by Aedas and Arup (2012). It consist of particularly designed sun screen elements made of fabric and moved by robotic arms. The design of the shading elements is inspired by the Arab tradition of Mashrabiya. However, we clearly recognize a precise reference to the shading system designed by Jean Nouvel for

the south façade of the Arab World Institute in Paris (1987). A very important feature of the sunscreens is their color. Many contemporary architects have worked on this issue: Jean Nouvel (Hotel Puerta America in Madrid), Architecture Studio (Advancia Business School in Paris), Sauerbruch & Hutton (Cologne Oval Offices in Köln) and many others. But one of the most interesting innovation feature of contemporary design is the integration of the sunscreens with lighting technologies, like LED. See for example the Ginza Pola Building in Tokyo designed by Nikken Sekkei + Yasuda Atelier (2009). Dynamic façades with smart materials and technologies: new systems for better performances In a totally synthetic way, we can say that smart materials for the realization of dynamic sun screens and façades can be grouped into three large families: materials that change their color, materials that convert light and moving materials. Materials that change their color can be applied on electro-chromic glass. The glass change its color according to a passage of electric current which modifies the chemical structure of transition metals oxides or organic compounds contained in a double-glazing. There are also FC (photochromic) frames, also called “smart windows”. They react to ultraviolet radiation and the metal salts and the organic compounds contained in the double-glazing change their color. Materials that convert light are best known as photovoltaic materials. In addition to the widespread silicon photovoltaic technology now we have technologies that require less energy to produce photovoltaic cells. For example we have the thin-film photovoltaic technology based on cadmium telluride (CdTe) or cadmium sulfide (CdS). Other thinfilm photovoltaic systems are the CIS (Copper, Indium, Selenium) and the CIGS (with Gallium) and other ones.

Moving materials react to changes in temperature or electrical impulses by contracting or recovering their initial shape. Among these materials we have electroactive polymers (EAP) that react to an electrical stimulus (electric current at low voltage) with a mechanical deformation. They are also called dielectric polymers and used for homeostatic façades. They require external sensors to feel the environmental conditions. We have also Shape Memory Alloys (SMA) such as the Nitinol (nickel-titanium alloy) a navy alloy that, once mechanically deformed, it recovers its original shape by heating. And we have also Shape Memory Polymers (SMP) that recover their mechanically deformed shape by heating. Smart glass is a reality that is finding application in many contexts because it doesn’t modify too much the appearance of places. Brise-soleil with the integration of photovoltaic cells are spreading rapidly in the building industry. But we have also alternative solutions like the integration of thinfilm photovoltaic strips in fabrics for sun protection, as already seen in the fashion industry. Kennedy & Violich Architecture (KVA MATx Studio) from New York designed in 2007 the Soft House and in 2012 the Soft House 2. It is the prototype of a house whose windows are protected with curtains made of polyester, aluminum with a thin-film photovoltaic integration. The textile distributes renewable electrical power, adapts to the changing space needs of living and working in a compact home and generates up to 16,000 watt-hours of electricity – more than half of the daily power needs of an average household in the US (www.kvarch.net). But perhaps the most interesting application of smart materials in architecture is related to the homeostatic façades.In 2010 the architects Decker and Yeadon of New York applied the homeostasis principle to a new system of sun-shading.

This system fits into a double skin façade and takes advantage of the unique flexibility and low power consumption of dielectric elastomers (Fig. 1). The actuator is an artificial muscle, consisting of a dielectric elastomer wrapped over

a flexible polymer core. Expansion and contraction of the elastomer causes the flexible core to bend. A roller at the top of the polymer core ensures smooth motion as the elastomer moves (www.deckeryeadon.com).

Conclusions These examples bring us back to common roots that identify cultural references that have contributed to the design of these devices. I am referring to the tradition of sun screens in countries with warmer climates but also to the architectural designs such as the high-tech architecture of Jean Nouvel. But probably the cultural reference that might be more useful for further research on the design of the sun screens (especially the latter made with smart materials) refers to Kinetic Art of the Sixties. I refer in particular to the work of Manfredo Massironi (1937-2011) and his constant pursuit of representing movement through objects and static images.

Note Addington D. M., Schodek D. L., Smart materials and technologies: for the architecture and design professions, Architectural Press, Oxford, 2005. Gasparini K., Design in Superficie. Tecnologie dell’Involucro Architettonico Mediatico, FrancoAngeli, Milan, 2009. Gasparini K., Premier A., Zennaro P., “Building Envelope Requalification. Guidelines for Recovering Social Houses” in Di Giulio R., editor, Improving the Quality of Suburban Building Stock, COST action TU0701, UnifePress, Ferrara, 2012, pp.6. Massironi M., Fenomenologia della Percezione Visiva, Il Mulino, Bologna, 1998. Premier A., Superfici Dinamiche. Le Schermature Mobili nel Progetto di Architettura, FrancoAngeli, Milan, 2012. Ritter A., Smart materials in architecture, interior architecture and design, Birkhäuser, Basel, 2007. Zennaro P., Architettura Senza. Micro Esegesi della Riduzione negli Edifici Contemporanei, FrancoAngeli, Milan, 2009.