Green Building is a process for the reevaluation of current building technologies.
Because of Paolo Soleri's beliefs in frugality and his goal of creating Arcosanti as the Lean Alternative, it is understandable that people would expect that Green Building and sustainability would be a priority.
However a careful examination of the new Arcosanti website Mission, Development Goals and Values does not specifically detail a commitment to sustainability or Ecological Design.
The Cosanti Foundation exists to promote the concept of Arcology developed by Paolo Soleri as an Urban Alternative, through educational programs, exhibits, and most importantly, through the construction of Arcosanti as an experiential example of the concept. We expect Cosanti Foundation will develop its urban laboratory prototype Arcosanti as a scalable demonstration of an alternative urban experience and will become a lean urban research and development center.
This statement while understandable given Soleri's reluctance to clearly articulate what he stands for and who he identifies with is not necessarily a way to clearly and decisively build support for the project among the public, corporate institutions and alum.
In the case of Ecological Design and/or Green Architecture there has been a reluctance to say Arcosanti is dedicated to the development of sustainable and appropriate technologies. This has to do with the idea in Soleri's mind that the sustainability as a whole is a part of what he terms the "better kind of wrongness" thinking that sustains suburban development and consumer culture. He believes the key and most important step is to build Arcologies as models for what he terms the Lean Alternative/Hypothesis.
While it might be good to see more specifics about what its means to be lean urban research and development center in the mission and values statement of the organization, its also evident that a real and thorough consideration of what sustainable - or if there is a reluctance to use that wording - what leanness actually means in terms of how measured are being developed to reduce environmental impacts at Arcosanti .
Green Building or Green Architecture involves various technologies and approaches that are designed to reduce the ecological impact of the building construction. It also relates to maintenance and how easily the building if it is modified and when it is eventually demolished is integrated back into natural systems. Green Building is a subset of Sustainability with a focus on building design and construction. It also is considered to be an area of expertise that overlaps with Ecological Design. The difference is that Ecological Design relates to the larger field of design of products and not just buildings. Ecological Design is based on the work of the pioneering Ecological/Green Architect Sim Van Der Rim and the book of the same name that he coauthored with Stewart Cowan.
The key criterion for Green Building is an effective process for evaluating technologies and building materials comparing existing practices with more ecologically sustainable ones. Human livability is often a consideration as well and so many in the field also use measures to evaluate human social well being in the buildings.
Various tools are used to establish the sustainability of the building such as software like IES Gaia. Tools for establishing the ecofootprint of the building are also important to understand the expected footprint of the building.
In terms of Reformulating Arcosanti, a most important step is to analyze the ecofootprint of Arcosanti. This includes a holistic system for evaluating the impact of Arcosanti's built environment on the surrounding ecology and also at the larger global level in terms of resources imported from around the world.
From such a study, a strategy can then be formulated that bases operational activities, new construction and retrofits based on an evaluation of what the priorities are and then establish a sequence by which they can be implemented at Arcosanti over time.
For example, concrete is currently the material of choice at Arcosanti. This came into being because Soleri had fondness for it based on his life experience and his belief that it lended itself well to the construction of his larger Arcology vision. It also helped that it was very malleable when mixed and poured so that interesting sculptural molds or forms could be made to make a fantastic looking building. However the making of cement involves the use of coal to transform limestone into cement in a kiln and this involves the release of CO2. When cement is also mixed with water and aggregates also leads to the release of CO2 as part of the chemical reaction that solidifies the concrete.
For the above reasons, its not clear that concrete is the best choice for Arcosanti especially when there are ways to use local materials to make compressed earth block, poured earth or cobb buildings with considerably less ecological impact on the environment.
At The Center for Maximum Potential Building Systems, one novel notion has been in regards to not only a modularity in design, but a building structures that can be rearranged like legos, into new configurations. Modular building may allow for reconfigurations based on changing conditions. The concept of creating innovative building materials that can easily be temporarily constructed and deconstructed, minimizing waste is a move towards a more sustainable energy pathway. It also has the potential to reduce building costs, in terms of being easily constructed. Thirdly it offers the advantage of rapid and temporary structures that may not be desirable at a location over the long term, but offer an effective short term solution to space constraints.
It is important to look at the full picture of embodied energy. Steel while very costly to produce from iron ore and coal, can be recycled at a relatively low cost. While concrete uses cement which is one of the most energy intensive building materials, and large CO2 culprit, cement is only about ten percent by concrete by volume. However sand, gravel and water as well as steel all have ecological impacts and are required to construct buildings out of concrete. In addition there are the forms which are made usually from wood, the sealants and the form release oils that have further ecological impacts.
In regards to concrete structures one can see that if they are improperly designed that they can represent a very wasteful form of building. With Arcosanti, I note that by making the secondary and tertiary floors in 6-8 inch concrete, allow with the structural beams needed to support them and the 8 inch thick walls, that you have a recipe for waste. While metal is an extremely resource intensive building material in terms of the energy required to make it, steel beams may be a more effective use of steel than rebar reinforced concrete. It goes like this, when you create unnecessary weight in the building--so using concrete when other cheaper materials are avialable--you have to design more structural integrity into the building just to support the weight (this is part of the reason why concrete becomes less cost effective, so much of itself is used to support itself). Esspecially in regards to the floors. Concrete floors have of course one of the highest weight per unit of strength ratios, thus
Economizing on the concrete (different struct. design or prestressed components) will reduce the significance of the load and minimize the air handling involved.
One of the major advantages of concrete is that it is one of longest lasting building materials. This means that over the long term it may be the most ecologically sensitive materials. However the problem we face is one where the ecological challenges remain present in the short term.
Adding Fly-ash to Concrete
Concrete is biggest greenhouse emitter in the building industry. In an attempt to save money as well as reduce the amount of energy used in the construction of concrete, Flyash a byproduct in the production of coal powered electrical plants is increasingly used. By rewriting codes allowing the use of fly-ash in concrete construction, the Holman company says that greenhouse gases can be significantly reduced.
Low tech building systems such as adobe or straw bale are relatively clean, simple processes. Straw bale is easy to construct and involves the use of a waste product--straw.