The ANSI Design
Exhibition of QUT Student work
ANSI challenges design conventions

ANSI challenges design conventions

Problems result from trying to optimize passive solar design according to the 'law of diminishing returns' and/or trying to replace site-specific design with generalized templates and rules of thumb. Under-design for solar resources often results in buildings that under-perform. This has had the cumulative effect of creating biases against passive design, even within the architectural profession. For example, if a building is not oriented toward the sun, it becomes an excuse for ignoring passive solar strategies when retrofitting the building.

ANSI’s passive design challenges many of these myth-conceptions by designing the walls as individual passive solar ecospheres for fauna, flora and ecosystem services. A wide range of eco-technologies are used to demonstrate how passive systems can be operated in different orientations, using a variety of strategies.

'Passive solar design all looks the same'

The same range of design styles are possible with passive solar design as with standard construction. Examples exist that range across the full spectrum from 'nuts and bolts' to 'nuts and berries'. Any construction can be enhanced by passive solar principles, so there is no reason why passive solar design should not accommodate varied regional traditions or personal preferences.

ANSI’s green wall system looks unlike other buildings because the walls themselves are modules containing ecospheres. These support natural systems that provide eco-services and small animal and plant life (too small to know they are in terrariums). ANSI thus combines hi-tech and low-tech design in one building design framework.

'Passive solar means orienting towards the sun (only)'

Direct heat gain and glare through windows can make rooms uncomfortable, and curtains need to be closed at night and open during the day. In contrast, conservatories or atriums allow heat to be collected when it is hot, and emitted into the room when it is cool, and the reverse. Heat can be vented into the home directly or delivered to a storage area with high thermal mass inside the home.

ANSI’s modular walls include ceiling height gabions containing small rocks that collect and store solar heat in winter, which can then be circulated through ducts that are housed in the adjacent triangular vertical structural trusses. These walls are automatically shaded on hot days and the warm air is ducted out by convection.

'Passive solar is more expensive'

The construction costs, embodied and operating energy, and overall life-cycle costs of passive solar design should be less than that of conventional construction - depending upon the training and experience of the designers and builders. When they do cost more, it is often because of 'experimental' features and the inertia of conventional practices.

ANSI’s structural system is modular and can be constructed off site, enjoying the savings that accrue to prefabricated constructions. For example, such structures are not delayed by inhospitable weather conditions during construction. If a system fails, it can be modified at low cost by changing the interior use of the ecospheres.

'Buildings must be spaced far apart for solar access'

The common idea that houses need to be spaced far apart for solar access has been based on the ostensible need for the sun to hit the wall instead of the roof. Passive solar collection panels can be separate from the building structure. The roof itself can be used as a collector and distribution system, as well as a greenhouse.

ANSI’s internal atriums provide thermal functions and collect or ventilate heat like a roof greenhouse. Two of these allow semi-private conversations in an internal garden for a variety of space. The other is a suspended walkway through an indigenous bird and insect and small animal species terrarium. The floor of this area is the ground itself.

'Good solar access depends on the site'

Poorly laid out subdivisions or difficult sites are often used as an excuse for not applying passive solar design principles. An atrium or attached greenhouse can reduce heat loss through walls by 20 per cent and increase the usable floor space for little cost. Such improvements can increase both the capital value and uses of space in a building.

ANSI’s modules face a whole gamut of directions but are individually climate controlled. They are essentially ventilated double glazed walls with 3 integrated kinds of exterior screens controlled by interior sensors. The modules containing ecosystems needing warm environments will occupy sunnier locations. If the flora and fauna appear unhappy (or sensors indicate too little sun, shade or CO2), the local herpetology society or relevant community group can relocate the displays to another facade.

'Concrete slabs are necessary in cold climates'

'Cut and fill' of the earth to accommodate concrete slabs is often not ecologically appropriate. Concrete slabs, without edge insulation, are not even good insulators. Further, slabs have about four times the embodied energy of timber floors, not to mention greenhouse gas emissions. Thus, building off the ground with insulation (or underground) and using vertical thermal mass can be better.

ANSI’s structure 'floats' on the site above the ground and flood level. The vertical structural trusses that support the space frame and ecospheres have metal prongs at the base of each pipe. These do not require concrete footings. The thermal mass for heating is in certain exterior walls and for cooling is in certain internally-located vertical trusses. Ecosystems with a greater tolerance for temperature variation can live (and be studied), while providing living wallpaper for the building users.

'The building materials are not important if insulated'

Conventional building materials have huge environmental costs during resource extraction and disposal, high embodied energy and greenhouse impacts, and adverse health impacts. Alternative bio-based materials, such as engineered timbers or wheatboard, are good insulators and do not (necessarily) off-gas toxins. Also, the use of local materials greatly reduces transport (greenhouse) impacts.

ANSI’s structure avoids the use of concrete, rather than just blending concrete with carbon absorbing materials or waste. However, some walls are solid and are used to demonstrate a range of sustainable wall materials. Because the structure provides visually unifying framework, different materials and insulation methods can be displayed without creating a cluttered effect. The building will utilize literally dozens of new eco-innovations that apply to eco-retrofitting as well as new buildings.

'The impacts of apartments are lower than those of detached dwellings'

The total material flows, embodied waste and operating energy, and so on can be higher per square metre in apartments and tall building than in detached dwellings - depending on design. While apartments have shared walls and plumbing, they can be more difficult to convert to resource autonomy. Yet some developers justify environmentally deprived buildings on the grounds of higher density alone.

ANSI’s plan has commercial areas with additional floors for office and low-cost eco-hotel accommodation for student visitors. The structure has relatively low embodied energy for low rise commercial space. Because of the open plan and versatile exterior, the buildings can be easily modified over time to integrate unanticipated changes in technology. Floors could theoretically be added or removed over time in the taller structures.

'Still air is important to achieve thermal comfort'

Still air stratifies. If the temperature at floor level is cooler than at head level, many people tend to get headaches. Warm internal air temperatures near cold walls or windows that draw heat from the body similarly cause discomfort. That is, heat from a small source such as an electric fan heater is less comfortable than heat from a large warm wall. Fresh air and natural ventilation reduce these air temperature differentials.

ANSI’s design uses radiant heating from the rock gabions and solar heating through the walls and atriums in winter. This openness to the environment means that variations in the internal climate due to the differing orientations are moderated by circulating air. However, the triangular truss structure contains ducts which provide variable temperature control in each space.

'Passive solar design does not cool buildings'

Solar stack, or solar chimney, technology can provide significant cooling by forcing warm air to rise out of the building using natural convection. This principle has recently been resurrected from ancient history for application in large buildings and even skyscrapers.

ANSI’s internal spaces are cooled via ducts in the vertical triangular trusses from under the building, and/or through water storage 'badders' that sit on the ground. Rock storage at the base of the vertical trusses work as a Solar Core (see Positive Development). The interior atriums assist in ventilation in summer and most vertical trusses have manual ventilation ducts.