Friday, February 8, 2008

Net Zero Effect

One of the plethora of terms floating around the design-o-sphere is Net Zero Homes (aka ZEB or zero-energy building). Another fancy term for the same thing? Sort-of, but with a slightly different spin. Simply, it is a building that has a net energy usage of zero over the course of one year. Spawned by the impacts construction has on climate change, as well as reduction in fossil fuel consumption - it has caused some radical re-thinking of how we do things in the design world. A good resource can be found at Architecture 2030.

Recently announced on BuildingGreen, the State of California is taking the challenge, seriously. All residential buildings will be required to be net-zero by 2020 with commercial buildings following suit by 2030. The photo below is one of 4 model net-zero homes in California:

:: image via BuildingGreen

This doesn't mean merely slapping PV panels on a California Ranch and calling it good. Design potential is huge in addition to the value of net-zero as a branding and marketing opportunity for new development. A fantastic small-scale net-zero example, via Inhabitat, is 'Glass and Bedolla House' by Chicago architecture firm Zoka Zola Architecture + Urban Design.

:: image via Zoka Zola

What makes it net-zero? For starters, PV panels, solar heating, and geothermal all add to the energy-efficient production side. In addition, operable windows are aligned to allow for cross-ventilation, and the placement of openings along with vegetated walls and deciduous canopy trees aid in seasonal reduction of heat-gain, while allowing winter solar access.

:: image via Zoka Zola

Using landscaping and site orientation as a significant site feature. By smart orientation and using the microclimatic benefits of trees, living walls, and ecoroofs, the overall reduction of energy use in a home can be significantly reduced. This ties into, but expands, the concept of daylighting design by providing an active agent (i.e. the plants) to aid in even more efficiency. This is also first-year Environmental Design studio stuff - but how many times does this get missed or ignored in the building processes?

The following series shows sections and plans from summer solstice and winter solstice and the different mechanisms at work.

:: images via Zoka Zola

While the preponderance of new 'green' terminology abounds, a careful reading of the specific details of each shows both the similarities and differences, and allows for application that is more appropriate for a particular project. As with many strategies, net-zero benefits are maginfied with the creative and smart use of vegetation, which for years have been mediating building microclimates. Looks like we can come full-circle.

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