Image credit: City of MelbourneThe 10 story Council House 2 (CH2) building in Melbourne is very likely Australia's Greenest Building. It is the first building in the country to receive six stars in the Green Building Council of Australia rating system.
The building is wrapped with photocell-controlled louvers made of recycled wood which help to temper the interior environment by controlling solar gain. Prominent shower towers are used as part of the cooling system for the building, and a set of large wind turbines on top of the building help to exhaust stale air out of the building. In addition to the visually striking aspects of the building, it also contains a host of features inside that contribute to the building serving as an exemplar of sustainable design.
The building is 12,500 square meters (134,500 square feet) and serves as an office building for 540 City of Melbourne staff, plus ground floor retail space. However, the underground parking includes only 20 parking spaces, but 80 bike spaces are provided (and 9 showers for cyclists are also part of the building's amenitites).
A diagram of the building schematically shows the many sustainable features incorporated in the building. CH2 uses agressive water recycling and reclamation. A multi-water treatment plant in the building draws in 100,000 liters (26,000 gallons) from the municipal sewer, as well as any site-generated waste, and filters the water to create A-grade clean water suitable for all non-drinking uses, including water cooling, plant watering, and toilet flushing needs. In this way, the building goes beyond its own needs and actually helps improve water quality in the city by treating other waste and using it for building needs.
South Elevation: Image credit: City of MelbourneChilled ceilings help to absorb excess heat from the building and keep it cool and comfortable in much the same manner as radiant heating. The building's power systems include photovoltaic cells, solar hot-water panels, and a gas-fired co-generation plant. The "shower towers" on the shaded side of the building use evaporative cooling effect to cool air and water for building cooling. Even the ducts on the north and south side of the building are colored differently in order to utilize natural heating and cooling in ventilating the building.
The building also incorporates light shelves to reflect natural light into the building and enhance the use of natural rather than artificial light. Glare is also controlled with louvers and other shading devices. The north facade (which, in Australia, is toward the sun) is covered with a vegetated facade to filter sunlight and reduce glare. Artificial lighting is controlled by sensors to turn off when adequate natural light is available.
Image credit: City of MelbourneThe website for the building includes breakdowns on the cost, including base building cost and cost of sustainable features (which is broken out as 22.1 percent of the building's total 51 million Australian dollars). Being a public building, it is much easier to get these figures than it is for most private building projects.