Grocon’s new Pixel building in Melbourne, which has just attained a flawless 6 Green Star score, is the world’s first carbon neutral office building. But does a world-class green rating necessarily produce the world’s best offices? JOHN POWER investigates.
During a recent (pre-fitout) site visit to Grocon’s new Pixel building, in Melbourne’s inner-northern suburb of Carlton, the building’s sustainable design features were immediately obvious: three rooftop vertical axis wind turbines, alongside both fixed and motorised arrays of solar panels; multicoloured façade shading panels cladding most of the building; a rainwater-filtering roof garden and ‘living edge’ wetlands on the external perimeter of each level.
While these highly viewable features certainly contribute towards overall efficiency, the real ‘green punch’ is derived from a blend of behind-the-scenes innovations. The most remarkable of these is a new form of concrete – Pixelcrete – that incorporates a high degree of recycled material, resulting in a 60 percent reduction in carbon production compared to conventional systems. The steel reinforcing is also recycled, as are the carpets (cut into squares for easy replacement).
The building, set on a small corner site of 250 square metres, comprises 837 square metres of lettable space over four levels. In the immediate future, the developer Grocon will use the building as a display complex for a proposed adjoining redevelopment project.
Recently, the building achieved a perfect Green Star rating score of 100 points, easily earning its 6 Star Green Star status from the Green Building Council of Australia.
Umow Lai, the building services consultant and sustainability firm responsible for overseeing the design of the project, worked with Grocon to satisfy the brief, which called for the creation of a zero-carbon building, as measured against an anticipated lifespan of 50 to 60 years.
Speaking on-site, Umow Lai’s director and principal sustainability consultant, Shane Esmore, says the $4.8 million base building ranks among the greenest office buildings in the world.
“In keeping with its outstanding environmental advancements, Pixel is gathering attention on the world stage, aiming to achieve the highest LEED score and rating (Platinum) to be achieved from the US’s Green Building Council, and the highest ever BREEAM Rating (Outstanding).”
FROM A DISTANCE
Even from a distance the building’s pixelated façade is a striking point of difference. Consisting of dozens of fixed panels of vivid colours arranged at different angles to minimise heat gain and maximise light penetration, the façade resembles a harlequin’s cloak. Apparently, the final panel configuration required 30 modelling revisions to
perfect. These external panels, however, are perhaps the most problematic design feature of the structure, insofar as the ‘fixed’ nature of these solid installations could feasibly lead to at least three significant problems: the steel panel arms could pose difficulties with the cleaning of the predominantly unopenable double-glazed windows; the so-called permanence of the daylighting solution may suddenly weaken in response to the organic growth of external ledge plants (not to mention the known or potential construction of numerous high-rise buildings in the immediate vicinity); and, as far as building users are concerned, the panels may come to be viewed as visual obstacles rather than insulating shields; i.e. when looking out, a pixelated view of a streetscape may well be considered to be a claustrophobic annoyance rather than a welcome screen.
As mentioned, there are ledge plants on each level and, while native hardy plants have been selected for their low-maintenance attributes, they may also be deemed ‘ideal’ solutions rather than winning design elements. There are no easy access points for the removal of dead organic matter, bird droppings, weeds or windblown litter. Furthermore, a single inadvertent application of the wrong window-cleaning detergent, one imagines, may interfere not only with the health of the plants, but also with the safety of the grey water they filter for ultimate collection in a 25,000-litre water recycling tank below. The ledge plantings are part of an elaborate water collection and treatment process that also involves a sizeable roof garden.
ON THE INSIDE
Fixed design elements extend inside the structure to include underfloor air vents, which, though serving as conduits for 100 percent external fresh air, may also restrict the ease of internal workstation/floor plan reconfiguration in the event of swiftly changing occupant needs. Similarly, the main lighting arrays of approximately 15 pendant lights per level do not appear to offer much positioning flexibility for such fittings as modular or moveable partitions or workstations.
With regard to acoustics – admittedly, this site visit took place prior to the interior fitout – it was noticeable that the lack of a suspended ceiling could feasibly hamper the ability of acoustical designers to overcome potential noise reverberation problems beneath the concrete slab ceilings.
Another practical problem, and a significant one, is the lack of any underground or on-site car parking spaces. While there are a number of bicycle racks, which is ideologically laudable, it would be interesting to see how many personal heaters a team of rain-soaked office workers may need to dry off, following exposure to a wintry Melbourne rainstorm.
ENERGY, WATER SAVINGS
The water management system, which Esmore says could allow the building to be disconnected from external water mains, if desired, incorporates some common sense features like vacuum pump toilet flushing (0.5 litres of water per flush), as well as waste treatment to produce methane. The methane, in turn, is used to fuel hot water heaters for showers. While recent regular rainfall patterns have been well-received, one can only speculate how a return to drought conditions may affect the maintenance of the rainwater collection system.
With regard to energy savings, according to Esmore, the three vertical axis roof turbines are made to handle Melbourne conditions, twirling into action once winds exceed 3.5 metres per second and functioning smoothly at seven metres per second (compared to the more usual 12 metres per second for some other units). At the time of our visit one of the three turbines – the one farthest from the main street frontage – was inactive.
Cryptically, the energy production of the turbines was expressed in terms of its power output in a domestic application (each turbine is said to produce 60 percent of the energy required to power a typical Melbourne household; the proportion of energy produced by the turbines in an office environment was not mentioned).
Highly efficient heating and cooling systems are perhaps the most successful attributes of the building. An ammonia absorption heat pump/chiller, which uses natural gas to directly fire the ammonia absorption cycle, and an air-cooled condenser are used to cool the lower layers of the exposed concrete slabs between levels – rooms are therefore cooled silently and comfortably.
With its highly visible use of recycled materials, genuinely innovative technologies relating to concrete fabrication and installation, and state-of-the-art heating and cooling systems, Pixel serves as an admirable and bold model of many features that will no doubt become mainstream in tomorrow’s commercial buildings. Not surprisingly, the building was awarded an additional five points for innovation as part of its perfect Green Star rating.
It is a matter of personal opinion as to whether the model can be transformed into a user-friendly, easy-to-maintain, affordable and practical office space; much will depend on the nature of future occupants’ businesses, the willingness of maintenance staff to maximise the value of the numerous energy- and water-saving assets, and the extent of high-rise development in surrounding city blocks, particularly to the north and west.
Umow Lai has now been engaged for the fitout of the offices (currently underway), with the aim of achieving a 6 Star Green Star Office Interiors rating.