- Article by Online Editor
- Photography by Courtesy Cida de Aragon; Architectus
Since the foundation of his practice Ingenhoven Architekten in 1985, Christoph Ingenhoven has been an advocate of sustainable design and low-energy architecture. He is considered by many to be the most successful German architect of his generation and a leader in the application of sustainable design concepts using an ecological approach. It is obvious that Ingenhoven is influenced by the work of other modern German architects, such as Egon Eiermann, Frei Otto, Thomas Herzog and Günter Behnisch, all of whom understood so well the relationship and tension between architecture and engineering.
Christoph Ingenhoven is involved in projects all over the world, including here in Australia. In partnership with local firm Architectus, his new Space high-rise office tower on Sydneys Bligh Street is to be completed in 2011 and he has also been involved with the urban and architectural design of Sydneys Barangaroo waterfront development. Sydney will gain a prominent addition to its skyline with this new (six-star Green Star rated) office tower on Bligh Street.
In May 2009, I met with Ingenhoven in Sydney, to discuss the future of green design.
Steffen Lehmann: Christoph, at the beginning I would like to talk with you about the challenges of designing for sustainability at an urban scale. How can we best address the broader requirements for the necessary transformation of cities and their energy landscape?
Christoph Ingenhoven: Public space, and the city as a whole, are always much more important than a single building. If we think about sustainability as a necessity, its still very complex, but not impossible to build city districts entirely without carbon dioxide emissions and zero waste to landfill. Mixed-use is thereby one of the most important aspects, because it is a prerequisite for achieving social sustainability. For example, at the new university campus in Dublin, which we are currently planning, we are incorporating a series of existing buildings in the master plan. New campus structures will have large sophisticated roof shells with building-integrated photovoltaic panels and wind turbines. These buildings will provide more energy than the campus will need to operate.
SL What exactly is your involvement with the Barangaroo waterfront development in Sydney?
CI We have been invited to be part of a large international team, with JPW and landscape architect Peter Walker, Leighton Properties, Mirvac and Macquarie Bank, and we are competing here with the team of Richard Rogers. I see the Barangaroo project as Sydneys last chance to significantly expand and transform its CBD through genuinely mixed-use sustainable strategies. Sydney will need to keep up with changes to stay competitive with other cities such as Singapore or Shanghai. At the same time, Sydney needs a very good, long-term plan that improves its sustainability performance. The city must continue to evolve in order to remain competitive, by integrating density in commercial and living spaces, bringing people back to live in the city centre. Efficient public transport will play a major role in this transformation process.
For Barangaroo, we developed the idea of energy islands, where much of the required energy is generated locally on-site, or at least as close by as possible, using solar-PV and wind turbines along the harbour. The idea of autonomous energy production with small units on-site is very interesting, and we also propose to reuse an existing wharf building that is already there. Our concept for Barangaroo hopes to extend the CBD by improving and complementing the setting, and reduce the energy needed for this new district by having the right volume, exposure, façade and, of course, by having the right systems in place. A better life-cycle and potential reuse, allowing for changes of structures in future, means more flexibility. Barangaroo is Sydneys great chance to be one of the sustainable 21st century cities.
SL A lot of your design work is research-led and based on in-house knowledge built up from one project to the next, an aspect not dissimilar to the practices of Norman Foster or Renzo Piano. Given that you are now involved in projects from Osaka to Sydney to Luxembourg, how do you feel about exporting this German know-how globally?
CI It seems to me natural to export this know-how. I think German architecture has been very committed to green buildings for a long time, and this has presumably something to do with what others call German angst, which could also be described as being scared about the environmental pollution and destruction, health issues and security problems that we can see everywhere today. This development started around 25 years ago, but it is more than just a question of technology or detail it has grown to a unique approach and attitude. I do not think it is possible to export the solution, but it is possible to bring a philosophical approach and commitment to another place, never the solution as such. The final solution emerges from climatic considerations and the local contextual circumstances, which in every project need to be carefully analysed at the beginning.
SL Sustainable design is always about holistic approaches, about seeing things systemically and with regard to all the connections and implications of what we do, exploring and understanding the variety of solutions that are usually available to any problem. You frequently use large glass panels to achieve transparency in your designs, even in hot and humid climates such as Singapore or Osaka. Wouldnt it be more helpful to use prefabricated concrete panels to reduce the amount of heat gain? I know that you do not use glass wherever you build, but there is clearly a desire to build transparency, similar to the early modernists. Where does this urge come from?
CI This desire for transparency has to do with the human experience. Humans used to live constantly outside before we started to settle and, for me, this has something to do with an instinctive wish to live outdoors, directly experiencing the change of seasons and sunlight. Yes, transparency is difficult to achieve, because its a question of energy saving too, but even in a building like the Osaka Tower, if you calculate the amount of glass, its less than 50 percent, because you have the metal cladding and core areas, which are closed. We are always restricted by orientation and views, trying to keep out the steep summer sun with sophisticated sun shading devices. For instance, at the Bligh Street tower, the naturally ventilated atrium is completely oriented to the south, shielded from the sun. To ensure energy efficiency, we provide a double-skin façade with efficient sun shading in the space between. I dont want to be ideological about the question of materials and transparency. We have done wooden façades and brick façades.
For instance, the university building in Düsseldorf is nearly closed on the colder façade; only the sunny side is open, using passive design principles, and wide cantilevering roofs keep the summer sun away. The traditional house, with verandas around it, is actually quite transparent too. If you think of the traditional examples in Singapore, these provide flexible envelopes.
SL So the double-skin façade is a modern interpretation of the traditional veranda? Thats quite a poetic way to look at it.
CI Maybe its more like the modern interpretation of a multilayered window. I remember I was very impressed as a kid when I visited, with my father, [in] an old house on Lake Geneva, an area which has a mild climate. An old villa there had shutters outside the window for security reasons, then the window itself, which they called a winter window, had an inner window, and in between these two wooden framed windows was an inside shutter for glare control. In addition, they had two different layers of curtains on the inside one translucent and one for blacking-out. So, they ended up with six layers.
SL And you have only three!
CI Exactly! [laughs] But you see the technology is quite old. You can find it in vernacular architecture in the Alps, for instance, at old farmhouses. These frequently have so-called winter glasses, and they just put these in as is necessary.
SL I want to talk with you about the question of density in urban design, and the idea of the green high-rise tower. Can a high-rise ever be truly green?
CI They have to be green! In the future there will be no modern city without high-rises. Many German cities are shrinking as their population is in decline; they dont need high-rise buildings. But Asian cities are rapidly growing, and we find there they have hundreds, even thousands, of high-rise buildings for working and living just think of Hong Kong. We need high-rise towers on the global scale. So, why shouldnt we develop better high-rise models? The denser city is certainly the better city, but this doesnt depend on high-rise. Take, for example, Houston in the US, which has high-rises, but an appalling low overall density. It depends on the whole city scale.
Sydney has an extremely low density and is one of the biggest energy consumers per capita. On the opposite side, the city of Copenhagen, which has no high-rise at all, is one of the best cities in terms of energy efficiency. What does this all tell us? Its not about high-rise, but about other elements; for instance, the extensive use of the automobile has become a major problem, and it is essential to understand the need for more public transport and mixed-use neighbourhoods. Even in the European context, a single person commuting every morning and evening alone in a car uses more energy than a four-person family in a house. Sustainable urban design depends on the right mix of uses, the right densities and efficient public transport. We can reduce the energy consumption of a city by combining living and working, and by reducing the distances in between and therefore reducing traffic.
SL But all buildings you design are large mono-functional machines. For instance, the Lufthansa Headquarters is a huge complex and I know the brief has asked for this. Are there any new mixed-use typologies that are emerging? In this regard, what is, then, the future of Asian cities that are currently experiencing rapid urbanisation?
CI The city needs to be planned in a way that reduces dependence on the automobile. The land use in the city and public transport needs to be intensified. We need to upgrade on all levels, from new bus-based routes to light rail networks and cycle paths, if we seriously want to enhance mass transit. Of course, its still very difficult to do a real mixed-use high-rise typology. The bigger a single building is, the more difficult and unsafe it becomes. To be honest, the better solution might be to have office high-rises and residential towers side-by-side, not mixed in one building. Structure and service-wise its really difficult to do an environmentally sustainable project for both users. I would like to be realistic, its not about a single piece of architecture, its about the citys overall structure and intensification of use.
SL It seems today, a buildings sustainability rating correlates to its let-ability and therefore to its value on the real estate market. I would like to talk about the new tower in Bligh Street, which has been hailed as a benchmark building in integrative environmental design and construction in Australia, even before its completed. Its an elliptical tower, similar to Harry Seidlers cylindrical Australia Square tower from 1961, which, in fact, is just next door. How can you ensure it is a truly a new generation of green high-rise, without knowing the tenants and their fitout plans?
CI Our work is based on innovative and holistic solutions in terms of energy, sun shading and thermal comfort. The use of regenerative energies and resources, like geothermal energy and rainwater, plays an important role in all our building concepts, and so does the intensive integration of daylight, as well as natural cross-ventilation. The Bligh Street tower will be the first high-rise to receive a six-star certificate on the Green Star rating system. This tower will be equipped with a real double-skin façade and will be ventilated by an atrium stretching the whole height of the tower. Fifty percent of the ventilation will be provided by the double-skin façade. The building will capture great gap views to Circular Quay, and there is a whole range of things we have introduced that will make the project work well. For instance, the façade will allow us to have a 100 percent shading solution and glare protection, with perforated internally adjustable blinds within the 600-millimetre double-skin cavity. The sun protection is very efficient, while maintaining the views, so we can use non-tinted glass on the outer skin. This makes the building extremely transparent and will offer the user a different experience. The ventilated outer skin is made of clear glass, which will ensure a highly transparent building.
Also in regard to construction methods, we will exceed the standards: the concrete that will be used contains a much higher percentage of recyclable materials than usual, site amenities are solar powered and 90 percent of the rubble from demolition will be put back into the site.
SL Interestingly, the tower has a compact single shape. Frei Otto, the pioneer of light building, used to say that the human eye perceives those shapes that are the product of a successful natural evolution towards the most optimal form, as especially beautiful. You can be quoted as saying, Beauty is the logical consequence of necessity, logic, truthfulness, efficiency, simplicity and minimalisation. It seems to me that the buildings highly refined elliptical shape a distorted circle in plan deals well with the diagonal shift that occurs here in the main city grid, the angle of Bligh Street and the curve along Bent Street. In addition, the flattened shape maximises harbour views from offices inside. I read that the towers elliptical plan is 12 percent more efficient than a rectangular building in its façade to floor area ratio so it also delivers economic efficiency.
What you propose for the ground floor is interesting. The office floors are pushed up to provide an open public space on the ground floor, with the tower above. This publicly accessible urban undercroft will make it easier to relate to the street level and surrounding context, and allows for more responsible city-making, I suppose.
CI Exactly. Maximising the view, while eliminating solar gain. The atrium is thereby another key element of the building and it allows natural light to penetrate deep into the floor plate. Ventilating through the atrium also means that the offices stay noise protected. It creates a social hub for office workers and has balconies that project into the atrium void to provide naturally ventilated break-out spaces, which is important when we think of the next generation workspace.
What interests me first and foremost is how people will prefer to work in the next decade and how they envision an optimal work environment. Each floor in this tower will have balconies projecting into the atrium, creating social spaces and opportunities for interaction between tenancies. Sustainability has also a strong social component, and this part is about creating human public spaces and healthy working spaces.
SL What are the other challenges with this project, for instance, the unknown user requirements?
CI With rental office buildings there is often a disconnect with the end user of the offices, the unspecified tenant that will occupy the building. This has the disadvantage that we cannot communicate with the future users during the design phase, and need to make decisions based on assumptions. We try to predict future tenant requirements and focus on indoor environmental qualities and energy efficiency. Of course, the performance of the design is also dependent on the fitout and how the tenants will operate the building.
While the tower has the potential to be fully naturally ventilated, it depends on the final fitout from the tenant. Much of the cooling will be provided passively, by activating the thermal mass of the concrete slab. If realised to a high standard, our double-glazed façade concept will allow naturally ventilated floor space for high rise offices, something that is possible even in extreme climatic conditions like during summer in Sydney, when the temperature outside can reach 35 degrees Celsius.
SL Christoph, thank you for the conversation.