Award-winning building designs draw on nature's technology

Termite mounds and Great Zimbabwe’s ancient stone walls inspired the innovative design for an award-winning office complex and shopping mall built in downtown Harare, Zimbabwe, in 1996 that uses only natural means to cool and heat the building, dramatically saving energy and costs for its tenants. Now an English research project is hoping to discover ways to introduce those termite mound construction secrets into the mainstream housing construction market.

Architect Mick Pearce developed a natural ventilation design that uses Eastgate’s building mass as insulation and daily temperature swings to keep the building cool and fresh. The system mimicks how termites keep their mounds at a constant temperature of 30 to 31 degrees, by digging a “breeze-catcher at the base of their mound, which cools the air by means of chambers carved out of the wet mud below, and sends hot air out through a flue to the top. They constantly vary this construction by alternatively opening up new tunnels and blocking others to regulate the heat and humidity within the mound.” Or to put it another way, termites have “found an air-conditioning system that works without a power station.”

Eastgate uses less than 10% of the energy of a similar-sized conventional building, says the Biomimicry Institute, which promotes the idea of basing human designs on natural systems. “Eastgate’s owners have saved $3.5 million alone because of an air-conditioning system that did not have to be implemented. Outside of being eco-efficient and better for the environment, these savings also trickle down to the tenants whose rents are 20 percent lower than those of occupants in the surrounding buildings.”

Eastgate’s exterior was inspired by the stone walls of the ancient city of Great Zimbabwe, 200 miles southeast of Harare. Pearce “looked to nature and local cultures for a solution to sustainability. This goes to show that local culture and the realities of the natural geo-climatic region have much to teach those who are willing to reject standardised ready-made solutions,” said the citation for the 2003 Prince Claus Award presented to Pearce.

Project TERMES (Termite Emulation of Regulatory Mound Environments by Simulation) at England’s Loughborough University is using new computer technologies to understand exactly how the termites achieve homeostatic regulation in their mounds so humans can learn to build our homes the same way, reducing waste and energy consumption and changing the "fabric of construction as we know it".

Pearce, who moved to Australia in 2002 as a result of Zimbabwe’s political situation, continues to innovate. His nature-based design for Council House Two, which opened in downtown Melbourne in 2006, is hailed as Australia’s (and likely the world’s) greenest and healthiest office building. Sustainable design permeates the $51-million, 10-storey building, which houses 540 city employees, ground floor retail space, and underground parking.

Features include: a water mining plant in the basement that uses membrane filtered sewer water to reduce mains water supply; phase change materials for cooling; automatic windows that open at night to cool the building; vaulted concrete ceilings that improve air circulation, cooling and natural light harvesting; a façade of louvres that track the sun to shade the Western façade; and, the use of wind turbines to draw hot air out of the building.

Although most of these principles are not new, never before in Australia have they been used in such a comprehensive, interrelated fashion in an office building. CH2 is the only building in Australia to be awarded a six star rating by the Green Building Council of Australia and is believed to be the greenest building of its kind in the world. CH2’s environmental features are expected to pay for themselves within 10 years. CH2 will use only 13% of the energy consumed by the existing Council House next door, and its emissions will be 60 per cent less than that scored by a top-rating five-star building. As a healthy building that has clean, fresh air and non-toxic finishes, CH2 is also expected to save millions of dollars otherwise lost to employers each year through sick leave and the reduced effectiveness of staff with colds, flu and other diseases caught and spread at work. 

CH2  is attracting widespread national and international interest as a model for the future. The CH2 Study and Outreach Program is a coordinated effort to consolidate the various opportunities for study, research, documentation and promotion and to significantly influence the building and related industries and generally raise awareness of sustainable design opportunities.

This story has been prepared from a variety of sources. The 2003 Prince Claus Award citation is found here, along with a list of Pearce’s designs, awards and presentations; Learning From Termites, AI Architect, February 2003 (reprinted from Tropical Architecture: Critical Regionalism in the Age of Globalization; Green building in Zimbabwe modeled after termite mounds, Abigail Doan Dec. 10, 2007; the Biomimicry Institute’s case study of Eastgate;  Animal Engineering: The Ultimate Smart Structure on the Project TERMES website; information about CH2 on the City of Melbourne website; and an Australian Broadcasting Corporation story entitled Council House Two - the eco-office block of the future, 19 April 2007. For a discussion of what building sustainability means in an urban environment, see Pearce’s 2005 lecture at Victoria University of Wellington School of Architecture.

 

UPDATE: During the 'African Perspectives' event held December 6, 2007 in Delft in the Netherlands, a joint initiative of the Faculty of Architecture at Delft University of Technology and the ArchiAfrika Foundation, Pearce delivered a fascinating lecture about the consequences of the fossil fuel energy crisis for the future growth of cities, and of development in general. In 'From Eastgate to CH2: building on the energy watershed', he talks about the nature of cities, and what cities will be like once fossil fuels run out. Here is just a taste of what he has to say:

"The city today is almost without exception a successful enterprise, in that 80 per cent of the planet’s assets are owned by 20 per cent of the people, all of whom live in cities (Carley and Spapens 1998). Their exuberant lifestyles impose impossible demands on the hinterland through the city’s eco­footprint. This lifestyle also imposes unattainable expectations on the remaining 80 per cent of the planet’s people. It is a way of life that, we are told, is attained with ‘democracy and development’ and it carries with it, consciously or unconsciously, a lie – a lie because, in order for all six billion people on the planet to achieve this lifestyle, the natural resources of four more planets would be required. Here is the dilemma. There is no question of the rich 20 per cent giving up anything, because it would mean a lowering of their living standards, and there is no question of the 80 per cent giving up the expectations so graphically presented to them every hour from cyberspace.

"Yet, the city still functions quite well: possibly it is a bit dysfunctional at the edges but, as the city is where every wants to live, the majority supports the enterprise. The problem is that the lifeblood or energy that is necessary to power cities is not only disastrously harming the environment and social order but it is also running out. The world isn’t about to run out of oil, but demand is now at 80 million barrels a day and as this grows, the production of easily extracted oil will peak and then start to decline. The view of when demand will come to a peak varies from 2006 to 2016 for the world outside the Middle East and, for the world including the Middle East, from 2023 to 2040 respectively. There is a growing body of opinion that even these estimates are on the optimistic side (National Geographic, 2004)." ....

“In the year 2050 humans have begun to relearn to live by sunlight just as the rest of the natural world had been doing for the previous three billion years. What Fredrick Soddy had predicted in the 1920s has come true. He saw the fossil fuel age as a flamboyant period of history, during which the natural capital stock of entrapped solar energy was used up. He saw the fossil fuel age as a passing phase, after which humanity would return to live by the sun. This vision has now become true, because the limiting factor to growth was the rate of flow of energy supplied each day by the sun. For as long as there had been enough resources to exploit growth, mainstream economics made sense. When oil reserves peaked in 2010, followed by the peak of natural gas reserves in 2020, the price of fossil fuels rose. World poverty and conflict could no longer be solved by development that was driven by economic growth. There were not enough natural resources left to support a high energy-consumptive lifestyle to fulfil the expectations of the 11 billion people on the planet. The price of fossil fuel made burning it in your car like burning diamonds. Three international laws now govern the use of natural resources and, therefore, world economies. These are the laws of scale, allocation and distribution which formed the basis of our taxation system.”

The entire lecture was published on the Dutch website, The Power of Culture. 

 


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