Sydney’s new Gehry building: how sustainable is it?
16 June 2014
By Cameron Jewell
16 June 2014 — The University of Technology Sydney’s Frank Gehry-designed Dr Chau Chak Wing Building continues to be slowly unveiled. The Fifth Estate recently toured the near-completed 5 Star Green Star Education Design v1 rated building with structural, civil and façade engineer Arup, and spoke to services engineer and ESD consultant AECOM about the challenges of integrating sustainability into such a novel facility, based on Gehry’s vision of a cluster of “tree houses” and likened by some to a “microwaved chocolate castle” or a “crumpled paper bag”.
While the building is undoubtedly an architectural and engineering marvel, questions have been raised over its sustainability credentials. Can such a unorthodox building – with no natural ventilation, a tiny raintank and a western facade made of large glass sheets – have good energy and water efficiency?
AECOM global director advanced design and applied research building engineering Lester Partridge told The Fifth Estate there were a number challenges faced achieving sustainable outcomes for an educational facility with many distinct areas that had flexible and transient use. However, the challenges weren’t insurmountable.
“That’s what engineers do,” Mr Partridge said. “We work with architects to realise their dreams.”
The exciting thing, he said, was that good sustainability outcomes could be achieved in such a complex educational facility, including services “designed specifically to reduce energy and water consumption, based on looking at how the building is being used and designing a system around that”.
“All up, it’s a pretty well-performing building considering the constraints.”
The building is mechanically ventilated, with Mr Partridge telling The Fifth Estate that adding natural ventilation would have been impractical for the building.
“It’s very difficult to naturally ventilate when you have a deep plan office building,” he said. “You can’t get air all the way through. It becomes impractical.
“When you’re building a naturally ventilated building you really need to design for that as the starting point. You can’t just retrofit natural ventilation.”
Because the building contains different, discrete areas, with offices, lecture theatres and meeting rooms all being used in a flexible, transient manner, the whole HVAC system had to be designed differently to what would typically be seen in a commercial building.
AECOM’s strategy found that dedicated airconditioning units serving the different bespoke areas – so individual control of the spaces was possible – was the most sustainable option.
So when a lecturer is not in their office, for example, the airconditioning system turns off. “It’s basically sensored,” Mr Partridge said.
“So the whole idea of sustainability here wasn’t to have something like chilled beams, or something you would normally put in a commercial building, but something that was actually very pragmatic for the type of building and for the usage of the building.
“And the same goes for meeting rooms, seminar rooms and lecture theatres.
“They’re all given with individual airconditioning systems. They all can just turn off when they’re not being used. Or they can be turned on after hours, as well.
“On top of that, we’ve also provided higher levels of outdoor air to those fan coil units throughout the space, which again in order to reduce energy we’ve demand controlled that through monitoring of CO2 and [volatile organic compounds]. And it’s actually double the minimum outdoor air requirement.”
The individual systems also have additional energy efficiency benefits.
“Because we have fan coil units serving dedicated spaces, we don’t have very long duct runs, so all of the airconditioning or fan coil units are located relatively close to where they serve,” Mr Partridge said.
“So the static pressure drop of those is very low, and with a very low static pressure drop you reduce your energy consumption from the fan – they don’t have to work so hard to push the air around a building. So again, that sort of system provides a very energy efficient operation – because they’re not only operating when they’re being needed, they’re also being operated with a very low resistance.”
The facade of the Dr Chau Chak Wing Building – done by Arup – is definitely striking, with undulating curved bricks studded with windows, and on the western side large sheets of glass jutting out like crystals.
On the tour of the facility, Arup lead structural engineer for the project George Cunha said the brick facade was designed to blend into the industrial landscape of Ultimo, while the glass facade would mirror the city behind it.
The “rolling” aesthetic of the building was achieved by individually laying bricks against curving steel substrate panels. And the large slabs of glass had to be designed carefully to minimise reflectivity issues.
The glazing looks impressive, but it must have made for some difficult engineering work to make sure it was also thermally efficient, right?
“It was challenging, absolutely,” Mr Partridge said. “But one of the things to remember is that as long as your glass is of a high performance, it actually becomes quite a small component of the energy consumption of the building.
“The glass there has a solar heat gain coefficient of 0.23, so only about 20 per cent of the heat from the sun gets into the building, and that’s only really in the late afternoon. And there are blinds there so occupants can actually provide some glare control.
“From an energy perspective, the glazing provides some really good daylighting, which reduces your lighting load, which in fact also reduces your heat load.
“From a perspective of running for the full year, most of your energy is really in your fans and your lights, not necessarily caused by your airconditioning load caused by the facade.”
A Council on Tall Buildings and Urban Habitat study Mr Partridge was involved in found energy loss from glass facades was actually very low when taking into account performance over a whole year, especially for deep plan office buildings.
The western facade also benefits from additional shading from nearby buildings to assist the high performance glazing.
“When it was designed and the glazing was selected, it was pushed very hard to make sure we had a very high performing shading coefficient,” Mr Partridge said.
Lighting and water
Similarly to HVAC, there is an automated lighting shutdown when people are not using spaces. The building also incorporates “a lot of LED technology”.
Concerns have been raised that a 20,000-litre water tank on the building was tokenistic, but Mr Partridge told The Fifth Estate such claims were not true, and that the use of the tank had to be looked at in regards to the overall building operation.
“The building actually uses air-cooled chillers so it doesn’t consume much water,” he said.
“It’s really only just serving toilet flushing, and that’s about it. If it had a big water-hungry cooling tower on the roof, then yes, [it would be too small], but we haven’t.
“We’ve also done away with the issue of legionella.”
The standard water-efficient appliances and fixtures are also used throughout the building, as well as a fire water reclamation system.
Materials and waste
Material use has been minimised, with a 40 per cent reduction in Portland cement over a reference case.
The building also features a large amount of sustainably sourced timber. A standout feature seen on Arup’s tour was a circular lecture theatre that extended up three floors comprised of glulam beams stacked on top of one another, with a timber staircase climbing up around it.
Low-VOC flooring and paint materials have also been used.
As previously mentioned in The Fifth Estate, display monitoring has been incorporated for occupant learning, with realtime energy and water data, and user interfaces displayed throughout the building.
“We’ve tried to provide a building which provides all the information in regards to what the sustainability issues are.”
The 11-storey, 16,000 square metre building is being constructed by Lend Lease and is expected to be completed in September.