By focusing on under construction projects and design proposals, I will discuss these issues by analysing some strategies and tools elaborated by architects and engineers.
|Skolkovo Center for Innovation © OMA|
I will start with the fact that we need to shift into renewable energies. But A question raises: how to do with existing building? Do we need to rebuilt — 60 percent of existing building fabric worldwide must be renewed in few decades — our building stock? Is it possible to build energy-efficient buildings? Do we have the technologies for? Can we do with existing technologies or should we develop new but expensive new technologies? Tasks of sustainable architecture are large: minimization of energy consumption, reducing building footprint impacts, etc., but must be challenged rapidly.
This paper bases only on tools and strategies elaborated by architects to construct new buildings or adapt existing buildings or, in a larger scale, urban environments to reduce energy consumption.
As a large number of researchers state (and I have already stated in previous posts), we need to find rapid solutions to face the issue of climate changes. Yet, I agree with architects who state that we must do much more than we do to construct ecologically sustainable buildings. As time is urgent to transform our way of building environment built, we must adopt rapid but efficient measures with existing technologies. A large number of examples of energy efficiency strategies and tools are currently applied in building construction: insulation, energy-efficient facade, photovoltaic cells, wind farm and geothermal system, and also green roof, to quote a few.
A first example is the solar power. As the Energy Report notes, solar power provides maximum level of light, heat and electricity. Designing energy storage that will improve the concentrating solar power (CSP) systems is a good example. These systems permit to store energy in the form of heat for up to 15 hours.
A strategy to store energy can be found in the orientation of the building. Depending on the orientation of sun, it is possible to concentrate and store solar heat and cool and heat building interior spaces.
The Morphosis Phare Tower design is conceived to respond to constraints — the site conditions aside — such as sustainability. The tower will be curved on south-facing facade which helps maximize heat gain and glare but flat on north-facing facade in accordance with the building's environment, precisely the wind load and the path of the sun. The building envelop will be optimized in response to the site specificity with a dual orientation.
|Phare Tower © Morphosis|
The flat North-facing facade is clad with clear glass panels which exhibit maximizing interior exposures to natural daylight depending on the location of the sun and amount of heat on its surface. Here even though Morphosis seeks to protect the building from heat gain and glare by opting for a curvilinear facade at the South, the agency attempts to store a maximum of solar energy to diffuse natural light within the building which can be a better response to minimize usage of artificial light. Another strategy to improve both energy efficiency and comfort of the occupant and to achieve optimal sun shading is found with the double membrane facade system. Brise-soleil will wrap the building's continuous South, East, and West glazed facades. An angle has been chosen for each of the 5000 stainless steel mesh panels in that the complexity of the tower's curving East-, South-facing facade, which is combined with the diagonal orientation of the panels cannot support brise-soleil louvers perpendicular angled to the direction of the sun's path, as calculated on the summer solstice.
|The King Abdulaziz Center © Snøhetta|
Snøhetta's Max-Lab design proposal for the National Laboratory is another example of implementing new strategies of building sustainable buildings: creating an interrelation between the building and its environment by modifying the volume. Situated in Lund, Sweden, this building is a circular shape twisted to create a dynamic form based on a Mœbius strip. Snøhetta's strategy is calculated to minimize up to 30 percent solar heat gains and glare thanks detailed solar studies for heat gain.
|111 Eagle Street Tower © Cox Rayner Architects|
Architects and engineers develop energy efficiency systems such as the COX Rayner Architects' Energy Building Systems (EBS) for the under construction 111 Eagle Street in Brisbane. This system is based on a passive energy design which is considered the most important element of the high-rise tower since it enables changes to the normal typology which technology does not permit. Energy savings are achieved through the use of high efficiency air conditioning and performance glazing in the facade.
|A101 Urban Block design proposal, © b4Architects|
Photovoltaics cells can convert sunlight directly into electricity as demonstrated by b4Architects' Energy diagram for the A101 Urban Block Competition Proposal Energy Building System (EBS). The agency proposed to install photovoltaic cells on roofs to collect solar heat. Photovoltaic cells can generate electricity via wind turbines or for direct heat. Walls are well-insulated. The agency wanted to install optimized solar gains system composed of brise-soleil and lodges. Like offices, the Urban Block would have an elaborated system to heat or cool the building blocks, on one hand radiant cooling system in summer and radiant floor heating in winter. A geothermal gas-fired has been installed for z geothermal gas-fired absorption heat pumps.
Recent research have shown the increasingly importance of wind turbine. The Phare Tower will be equipped with a group of wind turbines installed on the roof. This wind farm system will produce energy for the general services of the upper floors, to quote an example. As Thom Mayne mentions, wind farm system provides clean and alternative energy. The Phare Tower wind turbines consists of a passive ventine system which particularity is not to use electricity and to be noiseless.
This can be used in a larger scale — urban environment. The Energy Report estimates that, taking Danish example of wind already accounting for one-fifth of the country's production, wind power could reach at a quarter of the world's electricity needs by 2050. Discussion on the visible effect on the landscape can slow down the development of wind power depending on the way it is planned. On the contrary, positive impacts such as electricity production show that this type of energy saving can be an interesting option. We will see with the Phare Tower, when completed, if the wind farm system will be a response for envisioning a self-feeder building in terms of electricity.
It is now essential to integrate the natural resources of the environment. Natural resources can be mixed with technologies. Rammed Earth, to say a few, is a sustainable material which usage seems to grow even in Europe (Austria). For the King Abdulaziz Center, another under construction building, Snøhetta employs both innovative technologies and locally traditional materials (Rammed Earth). The task of this material which will clad the building is to provide stable temperature and humidity. It will complete the stainless steel which clad the pebbles which aims at providing both shade and ventilation for the insulated walls behind. This material will not be limited to produce shade and ventilation; it will collect solar heat to cool and heat the building.
In the case of the Dalian International Conference Center, Coop Himmelb(l)au develops a sophisticated energy building system articulating high technologies and natural resources. This system consists of radiant ceiling panels that will warm or cool the building depending on the season. Installation for heat recovery will help recycle energy use within the building. Concrete used as thermal mass keep the building on constant temperature. Basing on natural resources offered by the environment, the building will use thermal energy of seawater with heat pumps to cool and heat the building as well. Ventilation and natural light penetrate the building thanks to huge air volumes. The atrium will play the role of a solar heated and naturally ventilated sub-climatic area. As for the natural light, Coop Himmelb(l)au's Energy Building System appears to be another interesting solution to minimize the power consumption for artificial lighting.
But energy efficiency is not restricted to building. Green urban planning needs a urgent solutions, as well. Cutting building carbon emission will not be enough. Numerous research and projects highlight interesting possibilities to shift into sustainable urban centers. James Corner, West 8, Nina-Marie Lister, Interboro to quote but a few, are among these architects which call attention into this problematic. Their call has been heard. OMA, with its Think Tank AMO's research for a best living conditions in cities is an example. OMA's design proposal for the Skolkovo Center for Innovation competition attempts to develop a sustainable design and large-scale renewable energy planning that can be adapted in urban planning. Rather than a simple master plan, Skolkovo will be the occasion to set up technologies that will be developed within. OMA's vision of sustainable city can be considered a "participative" ecologically sustainable system. Indeed, the Stolkovo Exchange Center Energy System will be based on the participation of resident companies in the development of innovative solutions for energy saving, recycling, transport and communications systems. Here this is not only technologies, natural resources which can contribute to improve quality of life in cities while cutting energy consumption but also users.
Another way consists of retrofitting building stocks in order to adapt urban fabric to new technologies while reducing energy consumption. As OMA's project Roadmap 2050: A Practical Guide to a Prosperous, Low-Carbon Europe which aims at decarbonizing European power grid, it is possible to shift into sustainable cities with existing technologies. Can retrofitting be a solution? While Asian and Middle Eastern regions are facing with a massive urbanisation which permit these regions to build eco-cities — Tianjin, Masdar, Dongtan, Songdo —, Western cities cannot afford these projects. On the contrary, urban planners must find rapid and efficient tools to do with existing urban fabric. Chicago will attempt to challenge this transformation with its eco-smart grid city master plan which consists more or less of retrofitting urban fabric with new technologies which tasks are to cut emissions and improve living conditions for all users — workers and residents. This master plan include infrastructures, offices, transport, housing, that is, all the components that fabricate a city. This leads to the last point, the case of small scale building — housing, facilities, small offices and manufacturing.
And the small-scaled building
At smaller scale, architects use various strategies to build small scaled buildings. Innovative structural system, construction and environmental technologies contribute to the construction of small-scaled ecologically sustainable micro-structures.
|Study Hall in Sichuan © Zhu Jiangxiang, Photogrpahy © Xia Heng|
The 260-square-meter Study Hall, designed by Zhu Jingxiang in Sichuan Province, China, is an interesting example. Situated in a region which is concerned by disasters such as earthquake, the Study Hall, which is conceived for a life span of over 20 years, consists of a light composite structure system, with earthquake resistance reaching Mercalli Intensity Scale X and fire-proof and weather-resistant materials. An eight-centimeter-thick thermal insulation which helps resist cold weather composes the building envelope. This includes an optimized daylighting and ventilation to improve the comfort of the users. A space is reserved for the installation of a solar ground heating system to reinforce the efficiency of vents that create a stack effect which cool and warm the building depending on the climate (season). Wind turbine can be adapted to small building. It provides a total energy consumption from lighting as low as 1.2 kw.
As this paper has tried to demonstrate throughout examples of projects, architects and engineers know a deal about sustainable constructions. By studying these strategies constructing ecologically sustainable buildings, I have wanted to highlight that architects and engineers have sought out a new methodology of design, engineering and construction. They are providing a prescient new ecological paradigm for architecture that can be called sustainable architecture.