Laura Isabel Ettedgui Magna Cum Laude Bachelor Of
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LAURA ISABEL ETTEDGUI MAGNA CUM LAUDE BACHELOR OF DESIGN IN ARCHITECTURE SPRING 2010 SUSTAINABILITY + INDUSTRIALIZATION: structural considerations in the design of the Solar Decathlon house LAURA ISABEL ETTEDGUI magna cum laude // b.design architecture // spring 2010 ABSTRACT This project presents an assessment of various parameters for determining the sustainability of structures, particularly through an investigation into the structural materials. The guidelines of the Solar Decathlon competition provide a context and a model for the investigation. The competition highlights sustainability and industrialization as important themes, and research was conducted along these veins. As a modern buzzword, sustainability involves an ecological balance of resources, but it also carries the dimension of time in the longevity of the product. Therefore, research was conducted into life-cycle assessments for various industrialized structural materials. It was found that the energy consumed in the operation phase of a building far outweighs the embodied energy in the materials of the building. The project also investigates scales of modularity for the structure of the home, particularly in terms of the efficiency of shipping and assembly. The results of the research were applied to the structural and architectural design of the University of Florida Solar Decathlon house. LAURA ISABEL ETTEDGUI magna cum laude // b.design architecture // spring 2010 TABLE OF CONTENTS INTRODUCTION [1] 1. SUSTAINABILITY IN BUILDING DESIGN [1] a. significance [1] b. methods of assessment [2] c. implementation [3] 2. STRUCTURAL MATERIALS [3] a. life-cycle assessment [3] b. life-cycle properties of structural materials [4] c. importance with respect to total building impact [6] 3. SOLAR DECATHLON STUDIO [7] a. guidelines [7] b. research implications [7] c. design applications [9] CONCLUSIONS [11] ACKNOWLEDGMENTS [13] WORKS CITED [14] [NOTE: I am a double major with civil engineering and am submitting a similar paper for honors in that discipline.] LAURA ISABEL ETTEDGUI magna cum laude // b.design architecture // spring 2010 INTRODUCTION The Solar Decathlon Europe is an international competition between nineteen universities to build and operate a solar-powered house. The University of Florida is one of only two universities from the United States participating in the competition, which will be held in June 2010 in Madrid, Spain. A large team of students from eight different disciplines and four different colleges have been working on the project for over a year, beginning with the architecture design studio in the spring of 2009. As a double-major in architecture and civil engineering, my particular focus for the Solar Decathlon project was the structural design of the house, which I developed through a research project into the structural sustainability. However, what began as an investigation into the sustainability of structural materials, particularly in terms of life-cycle assessments, resulted in the discovery of the relative insignificance of the embodied energy of individual components of a building with respect to the energy-efficiency of the building as a whole. This paper presents the research that led to this understanding, as well as the applications of these ideas to the architectural design process. For the particular case of the Solar Decathlon house, the results of this research were relevant to various design decisions, and helped elucidate the relationship between architectural and engineering decisions in the context of green building. The implications of this paperʼs findings found real-world application in the design of the Solar Decathlon house, culminating in actual construction for the competition itself. 1. SUSTAINABILITY IN BUILDING DESIGN a. significance Sustainability, in terms of the built environment, describes the energy-efficiency of a building. This efficiency can be achieved by a low energy input to its components, low energy consumption of the building itself, or mere longevity - a literal capacity of the building to last. While trendy - the study of sustainable building has been growing in popularity since the early 1990s (Zhang 669) - the movement for sustainable construction is rather timely, given the simultaneous deterioration of both the environment and the economy over the last few years. The building sector is a major culprit in energy consumption as well as the generation of greenhouse gas emissions. Cited variously as constituting 30-40% or up to half of societyʼs total energy demand, buildings are responsible for about 44% of total material usage as well as about one third of all carbon dioxide emissions (Li 1414). Throughout the life of a building, “various natural resources are consumed, including energy resources, water, land, and minerals,” and the consumption of these is associated with the release of many kinds of pollutants back into the environment, which contribute to such problems as global warming, acidification, and air pollution and “inflict damage on human health, primary production, natural 1 LAURA ISABEL ETTEDGUI magna cum laude // b.design architecture // spring 2010 resources and biodiversity.” There is a clear consensus that “reducing the environmental burden of the construction industry is indispensable to sustainable development” (Li 1414). As technical systems, buildings are unique in terms of their relatively long life, as well as “their crucial role in the material and energy metabolism of the physical economy” (Assefa 1095). Sarja asserts that they are “the longest lasting and most important products of our society” (Sarja xi). Sustainable building design has the power to reduce the environmental impact of a building throughout its entire life (Wang 1415). Various parameters such as “reduction in energy input, lower environmental impact, lower waste production or maximum use of renewable energy” contribute to the overall sustainability of a building (Kumar 2450), as well as to the sustainability of our society in a world with limited resources. b. methods of assessment The overall sustainability of a built structure is impossible to quantify, but various “sustainability assessment toolkits” (Wang 1415) have been developed in the last couple of decades and are employed around the world (Assefa 1096). Some of the better-known of these include Leadership in Energy & Environmental Design (LEED) in the United States and Building Research Establishment Environmental Assessment Method (BREEAM) in the United Kingdom. Many of these systems involve a breakdown of various assessment categories or goals, including water efficiency and material choices. These categories are then assigned values, which are aggregated for the building in question to arrive at some standard of sustainability, such as LEED Gold or BREEAM Outstanding. “In this process fundamentally different aspects like indoor climate and energy use are added. Such a process implies subjective weighting with a number of shortcomings” (Assefa 1096). There are other systems, such as BEES and ATHENA, that are based on life cycle assessments and are considered more “objective evaluating models” (Zhang 669). The consideration of material choice is common to all of these assessment methods. Fig. 1 : The advantages and disadvantages of some main sustainable assessment tools (Wang 1416) 2 LAURA ISABEL ETTEDGUI magna cum laude // b.design architecture // spring 2010 c. implementation Despite the availability of “an enormous number of literature and sustainable design tools providing numerous sustainable design options,” the implementation of these tools is limited by inherent shortcomings in the tools themselves, as well as “by the affordability and risks the investors willing to take in practice” (Wang 1416). The most notable shortcoming of systems like LEED is the absence of life-cycle costs from the assessment scale. Life cycle assessment is considered to be an important link between the energy efficiency and financial feasibility of green construction; it is “the best tool to combine both the long-term environmental and the economical evaluations of building designs,” it and should not be neglected (Wang 1416). 2. STRUCTURAL MATERIALS a. life-cycle assessment Life cycle assessment is defined as the ʻʻcollection and assessment of the inputs and outputs of any potential environmental impacts caused by the product system throughout its life cycleʼʼ (Mora 1330). The life cycle of a system covers everything “from the acquisition of raw materials to the final disposal of products” (Zhang 669). Life cycle assessment is a well-known analytical procedure for assessing a productʼs sustainability (Gerilla 2779). The results are usually “presented in the form of aggregation of environmental loads or impacts related to the functional unit, without considering their distribution in time and space,” but they present a relatively “in-depth coverage of environmental impacts associated with design and building materials” (Zhang 669). Blengini asserts that, “in order to achieve the best environmental solution and to define the right proportion between the natural and recycled raw materials that are necessary for the economic and social development of mankind, all life cycle phases, from-cradle-to-grave, must be considered” (329). A key aspect of the life cycle assessment, which is often difficult to anticipate, is the recyclability of the product in question at the end of its life. Thormark cites various studies from several countries of the recycling potential of buildings