Page 1

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

Working with Nature Towards a Truly Sustainable Human Habitation Csaba Zagoni Centre for Alternative Technology REBE 16 November 2009

1. Introduction The environmental impact of construction, maintenance and operation of commercial and residential buildings is leading to significant irreversible changes in the global climate and ecosystem. According to the UNEP/Earthscan GEO-3 report (2002), if no radical change happens in current patterns, over 70% of the natural habitat on Earth will be destroyed or seriously disturbed by the built environment by 2032. The environmental impact can be greatly reduced by careful selection of construction materials, greatly reducing operational energy requirements and reusing building components at the end of a dwelling’s lifetime. This paper aims to investigate going beyond mere reduction of impact, by examining the principles of working with nature rather than against it and intends to thereby demonstrate a truly sustainable approach through general design guidelines for a simple rural habitation.

2. The global present: working against nature Today’s profit oriented consumer societies are based on constant economic growth. The over-production of items intentionally designed to be disposable or ephemeral, results in excessive amounts of waste being incinerated or sent to landfill, their valuable materials lost forever. Other side effects of present human activity include depositing massive amounts of toxic materials into the atmosphere, the waters and the soil; some of them so dangerous that future generations’ vigilance is necessary. Unsustainable rates of energy and raw material consumption lead to depletion of natural resources. Overall, the complex biosphere is being altered in an unpredictable way with global warming and loss of biodiversity being the first noticeable consequences (WWF, 2008). At the present the impact of energy consumption and greenhouse gas emissions by the building sector is alarming in both OECD and developing countries. The commercial and residential building sector consumes about 30% of primary energy in OECD countries and it is also responsible for about 30% of total greenhouse gas emissions of these nations (UNEP, 2007). In developing nations 70% of the energy consumed by the residential sector is provided by unsustainable biomass use (fig. 1, p. 2) resulting in deforestation and desertification (IAE, 2002). The building sector is also responsible for 30-50% of waste generated by OECD countries, 80% of which is recycled, however, most of the materials are “downcycled” into road foundations etc. (UNDP, 2003). Regulations do little more than accept the failure of design and provide a “license to harm” (McDonough and Braungart, 2002b). The response to regulations is increasing efficiency in minimizing impact, while slowly exploiting and poisoning the planet, which can be even more devastating on a global scale than a sudden collapse of the ecosystem in so far as the planet’s capacity to recover is concerned. Not looking at the source of the problem, as the population and the economy keeps growing, the overall outcome can be growth of impact notwithstanding. Humanity has separated itself from nature in that it has seriously altered energy flows and opened up the loops of natural biogeochemical cycles, treating resources as infinite and producing incompatible output. Unless human activity is finely integrated back into the natural cycles, humanity will soon have to face having to substitute “free” natural resources by costly technological solutions as nature disappears from Earth. page 1 of 7

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

Figure 1. Share of Traditional Biomass in Residential Energy Consumption, 2000. (IAE, 2002)

3. Working with nature: a truly sustainable approach The Brundtland Commission report of 1987 defined sustainable development as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Conventional sustainable design in architecture focuses mainly on energy efficiency and environmental responsibility (e.g. materials, water, landscape), aiming to minimize impact. While the ambition of this approach ― to reduce harm ― is good, as less energy is consumed and less pollutants and waste is produced by each design, it is still inappropriate as it doesn’t fit into natural energy flows and biogeochemical cycles (fig. 2, p. 2). Genuine sustainable development should have the intention of enhancing the well being of human culture and nature while providing economic value. (McDonough and Braungart, 2002b.)

Figure 2. Biogeochemical cycles (Hobbish, 2009)

page 2 of 7

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

3.1. Integration with natural cycles Ecosystems are immensely complex interdependent systems, with every member fitting and filling a niche in the whole organization. The concept of “waste” doesn’t exist as the output of any process serves as the input of others. The subsystems are finely balanced and self-regulating controlled by negative-feedback loops. Single elements of the subsystems can be highly ineffective, what really matters is the overall system performance and equilibrium. (Biogeochemical Cycle, 2009.) The basic concept of a sustainable building design is to find an ecological niche for the project by a site-specific approach. This means an onsite analysis of climate, vegetation, hydrology and landscape, as well as assessment of energy flows, evaluation of daily and annual sun, water, wind, vegetation and wildlife patterns (McDonough and Braungart, 2003). By creating a symbiotic relationship between the building and nature, it is possible to reconnect with the natural energy flow and biogeochemical cycles.

3.2. Materials as nutrients By understanding how ecosystems work, materials can be treated as nutrients in biological or technical cycles. Water, organic food waste, human waste and safely biodegradable construction materials can be part of the biological metabolism eventually enriching soil. McDonough and Braungart (2002b) show how other materials can be seen as valuable technical nutrients which can be endlessly reused in the technical metabolism instead of having to safely dispose of them, or recycle them into a less useful product before eventually being sent to the landfill. Products need to be purposefully redesigned for easy disassembly and reuse, rewarding the manufacturers with getting their valuable nutrients back at the end of the products determined lifetime. High-tech materials (e.g. polymer membranes) could be employed in domestic products where otherwise they would be too expensive if not regained after use. According to McDonough and Braungart (2002b), dangerous and highly-toxic materials need to be banned from the list of technical nutrients if they are potentially unsafe for the environment. However, if an otherwise toxic material is considered safe during normal operation (e.g. cadmium telluride in photovoltaic panels), as they are reused in a closed-loop cycle by certified bodies, they could be temporarily utilized until a better alternative is found. To make sure that these substances remain in the technical cycle and to reduce consumer responsibility, products composed of technical nutrients could be leased instead of bought, the manufacturers providing a full lifetime service and eventually safely reusing them. This approach eliminates the concept of waste, reduces manufacturing costs, and prevents valuable and finite resources of being lost forever in landfills. It also calls for a trustworthy, long-lasting product as opposed to the often unreliable and forthwith obsolete designs of consumerism. (McDonough and Braungart, 2002b.)

3.3. The energy flow According to the UNEP report (UNEP, 2007), more than 80% of the total energy consumed through a building’s entire lifetime is used during the operational phase (fig. 3, p. 4). Existing knowledge and technology allows a design of net energy exporting buildings by utilizing renewable energy systems. Overall, the operating impacts can be lowered to such an extent that the carrying capacity of the site is not exceeded. However, the impact of construction usually goes greatly beyond site capacity. (Olgyay, 2004.) By using life-cycle assessment (LCA) to sum all the embodied energy used in the construction of the building (including transportation and the components and replacements of the renewable energy system), the net energy exporting rate can be set to be in balance with the total energy requirement, aiming for a zero or negative overall impact throughout the building’s lifetime (Chwieduk, 2003). Figure 4. (p. 3) compares the energy consumption of an average building and a sustainable building over an estimated 60-year lifetime. Maintenance and replacements are included in the operating energy, and it is assumed that renewable energy technology is developing in terms of efficiency in the next 60 years. page 3 of 7

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

Figure 3. Energy used during construction, operation and demolition phases of a building始s entire lifetime

Figure 4. Energy consumed over the 60-year lifetime of an average and a sustainable building

4. General design guidelines for a simple sustainable rural habitation The basic model is taken from Pereira (2009) and extended and modified for the purpose of the design concepts previously discussed in this work. In the model suggested by Pereira (2009), the main structure is designed following passive solar design guidelines to take full advantage of the local climate. The materials chosen are locally sourced natural non-toxic materials with very low embodied energy and are ideally reused. The building has very good insulation (e.g. strawbale) and has sufficient thermal mass (e.g. rammed earth or adobe). The ratio of green roof to rainwater catchment is determined by the abundance of water on site. The collected rainwater is stored in a cistern after going through adequate filtration, and is mainly used directly for drinking/cooking purposes. page 4 of 7

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

Solar photovoltaic panels provide energy for high-efficiency LED lighting and low-power appliances (e.g. digital amplifiers, laptops). The energy is stored in valve-regulated lead-acid batteries. The whole system is leased from and serviced by a reputable supplier, who reuses the materials at the end of the system’s determined lifetime. A simple solar domestic hot water system supplies the low-flow shower and tap for hand washing. No detergents or other chemicals are allowed in the system except for natural biodegradable soaps. A high-efficiency wood stove provides backup heat for space heating and solar cooking. The fuel crops are sourced from a certified sustainably managed source. The composting toilet collects urine separately, which is diluted and used in garden irrigation and also acts as a natural fertilizer. The rest of the human waste is properly composted (at a given carbon to nitrogen ratio the temperature raises and kills all pathogens) and the resulting hummus is used in the garden to improve soil fertility. By doing this, the need for sewers is eliminated and waste is reintroduced into the natural nutrient cycle. Greywater is pre-filtered and directed to a mini-marsh with local plants (e.g. reed) before the cleaned water is used in the irrigation of the garden. (Pereira, 2009.) Further improvement over Pereira’s (2009) model, which recommends an organic garden, is setting up a permaculture garden. This is designed with great care to create wildlife corridors and to support biodiversity and soil fertility, aiming towards a natural landscape with complementary human presence. All fuel crops are ideally grown on site (e.g. short-rotation coppice). (Fairlie, 2009.)

Figure 5. Energy flow and nutrient cycle on site (Pereira, 2009)

Figure 5. shows the energy flow and the nutrient cycle on site. Energy is acquired from solar radiation and/or other renewable sources available on site. Water enters the system in the form of rainwater and it joins the nutrient cycle through cleaning/washing and irrigation. Solid organic nutrients are also circulated in the forms of food/human waste/garden compost between the cooking facility, the greywater marsh, composting facilities and the organic garden. Sewage and waste are totally eliminated in the conventional sense. Depending on the ecological state of the site previous to the design, the nutrient cycle resulting from human presence and the organic/permaculture garden can create a net increase in ecological services. By increasing the amount of moisture, increasing soil fertility and creating/improving wildlife habitat, the design can aim to have a restorative/regenerative effect, enhancing the ecological productivity of the land. (Olgyay, 2004)

page 5 of 7

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

5. Conclusion 5.1. Summary The current human activity on the planet is unsustainable, causing depletion of natural resources and seriously damaging the ecosystem. Regulations only aim to reduce the impact but they are not providing a solution to the source of the problem. For a shift towards sustainable development humanity need to reconnect with the planet’s energy flows and biogeochemical cycles. By using life-cycle assessment, buildings can be designed to be net energy exporters not only during operation but if looked over their whole life-cycle as well. Sustainable development can have a restorative ecological effect aiming for a human habitation where nature and human presence are complementary.

5.2. Limitations of the essay • lack of relevant data - because of the complex environmental, economic and social implications, the benefits of sustainable development such as the design presented in section 4 are hard to quantify • overall evaluation methods to analyze a timber frame, strawbale, rammed earth self-build were unavailable • available ecological footprint calculators are not flexible enough • only general guidelines are discussed here, major modifications might be needed for specific climates • the design assumes a very simple farming lifestyle probably not satisfactory for the majority of people of developed nations

5.3. Implications for existing orthodoxy • consumerism encourages a design of disposable short-life products • regulations only aim to reduce impact • conventional architecture looks at natural resources as infinite, and considers producing pollutants and waste as unavoidable • economy-driven decisions don’t consider social and environmental aspects • it is not widely acknowledged that the consumption of garden produce fertilized by composted human waste is safe

5.4. Future research • life-cycle assessment of a building suitable for a specific climate • calculation of typical energy consumption of a given lifestyle in a sustainable home • sizing of renewable energy system to meet the calculated energy consumption • comparison of ecological footprint of the given design and an average rural home in the same area • evaluation of the restorative potential of the design on agricultural land using monoculture page 6 of 7

Csaba Zagoni REBE CAT 0941436 - Module 2. Assessment (2009)

6. References Biogeochemical Cycle, 2009. In EncyclopĂŚdia Britannica. Available from EncyclopĂŚdia Britannica Online: (Accessed on 11 Nov 2009) Brundtland Commission, 1987. Report of the World Commission on Environment and Development: Our Common Future, United Nations, Transmitted to the General Assembly as an Annex to document A/42/427 - Development and International Co-operation: Environment, Available from (Accessed on 11 Nov 2009) Chwieduk, D., 2003. Towards Sustainable-Energy Buildings, Applied Energy, vol 76. pp. 211-217. Fairlie S., et al., 2009. Low Impact Development, Self-Published under Creative Commons license, ISBN: 978-1-870474-36-8 Hobbish, M.K., Earth Systems Science, Section 16, Federation of American Scientists, Available from (Accessed on 11 Nov 2009) IAE, 2002, World Energy Outlook 2002, Available from 2000/weo2002.pdf (Accessed on 11 Nov 2009) Jones, D., 1998. Architecture and the Environment, Laurence King Publishing, London McDonough, W., Braungart, M., Dale, D., 2002a. A Building Like a Tree, A Campus Like a Forest, Connections: The Journal of New England Board of Higher Education, vol 17. no 1. Summer 2002 pp. 16-19.! McDonough, W., Braungart, M., 2002b. Cradle to Cradle: Remaking the Way We Make Things, 1st Edition. North Point Press. McDonough, W., Braungart, M., 2003. Toward a Sustaining Architecture of the 21st Century, Industry & Environment, vol 26. no 2-3. pp. 9-12. Olgyay, V., Julee, H., 2004. The application of ecosystems services criteria for green building assessment, Solar Energy, vol 77. pp. 389-398. Pereira, T., 2009. Sustainability: An Integral Engineering Design Approach, Renewable and Sustainable Energy Reviews, vol 19. pp. 1133-1137. UNEP, Earthscan, 2002. GEO-3: Global Environment Outlook 3, Chapter 4: Outlook: 2002-32, Earthprint, London UNEP, 2003. Industry and Environment, Sustainable Building and Construction: Facts and Figures, Industry & Environment, vol 26. no 2-3. pp. 5-8. UNEP, 2007. Building and Climate Change: Status, Challenges and Opportunities, Available from (Accessed on 11 Nov 2009) WWF, 2008. Living Planet Report 2008, Available from all_publications/living_planet_report/ (Accessed on 11 Nov 2009)

page 7 of 7

Design with nature  

Working with nature towards a truly sustainable human habitation

Read more
Read more
Similar to
Popular now
Just for you