The 6 Star Green Star Global Change Institute at the University of Queensland was designed as a living laboratory and a working test case for a range of sustainability innovations. Among the aims were for the carbon neutral building to achieve net zero energy, operate in natural ventilation mode with no mechanical heating or cooling for over 80 per cent of the year and to provide a workplace that mirrors the role of the institute itself as a focus for research into how we adapt to a changing climate.
A year into operation and occupancy, key members of the design and consultant team have told The Fifth Estate there have definitely been a few aspects of the building and its systems that have required some adjustment.
- See our previous story Zero-energy, carbon-neutral Global Change Institute officially opened
One of the initial aims that has been overachieved is net zero energy use, with the GCI meeting all its own power needs every day in all seasons and exporting power generated by the solar installation to the grid four days of the week on average.
Thermal comfort, though, has been an ongoing process of adjustment, including fine-tuning the natural ventilation system, including the louvres and the technology that controls them, and the perforated sun shading that automatically tracks the sun to reduce thermal load on the facade. There have also been adjustments required by staff and students to an indoor ambient temperature that varies from 18 degrees to 28 degrees dry bulb temperature, depending on the season.
GCI research and special projects manager Dr David Harris, who oversees operations of the building, says that like any automated system it “had to become in tune with the inhabitants”.
“We had to tune the building, and the inhabitants also had to undergo a little bit of cultural change to how they work,” Harris says.
He says a lot of the control systems are complimentary to each other, such as the natural ventilation and light monitoring and controls. The human element also needs to be included, so inhabitants will take the initiative when needed to maximise ventilation by opening the windows a little more, and also have more acceptance of the level of background noise that results. This could involve needing to shift work locations to a quiet area when needed, or moving meetings.
The natural ventilation also means people will literally experience a breeze effect inside when it is in full open mode, as the airflow rate is higher than in a sealed space.
When the building is in conjoint cooling mode [when the ambient temperature is above 28 degrees], the air circulation system, which is based on evaporative cooling, dries the air out and takes out the humidity – a “double positive”, Harris says.
The cooling system is based on a hydronic system of chilled water pipes inside the geopolymer precast floor slabs, which have an access floor above the plenum with individual work-station controllable outlets for the airconditioning. The chilled water is produced using a free energy technology that chills water via the heat pump. In cold weather, the system works in reverse to provide heating.
“There is always a lot of variability with people’s ability to manipulate things locally if they want to,” Harris says. This means people accepting that there are some aspects of the building they simply cannot control, like the automatically controlled sunblades and louvres, which are linked to a weather system to dictate optimum operation for the conditions – including a completely closed position for the sunblades in high wind conditions as a safety measure.
“We literally have fine-tuning meetings every month,” Harris says.
“There have been multiple glitches, like the louvres not opening early enough in the summer to cool the building. All the original settings were based on what the consultants thought [would be optimum]. We had to have the thermal chimney adjusted to open on time.”
The final test of the energy consumption target was the performance of the building through all four seasons. Harris says that winter was not particularly cold this year in Brisbane, and the building retains a lot of heat gained through passive solar measures well. This meant that even though less solar energy was generated, the building still did not need to draw more power than it generates from the solar system and then stores in a locally invented zinc bromide battery system for draw-down to meet requirements.
“The mechanical heating wasn’t going on; we just didn’t need it. People put on a jumper and were quite comfortable,” he says.
“There are things that are still being tweaked but, generally, it is performing very well. It’s a really nice building, and a nice project – there’s no negativity in it.”
As a working experiment in sustainable construction, the aim has always been to learn from the GCI and apply those lessons to other buildings, advancing the knowledge and technological resource base of sustainable construction generally.
“Most of this [knowledge gained] is feeding back into the architects and engineers,” he says, noting that the building hosts multiple tours most weeks of people interested in its systems and design features.
Harris says he would like to look more closely at the efficiency of the thermal chimney.
“That’s a design refinement issue,” he says. “Does it need to be expanded for future applications, perhaps?”
“Another tweak would be to look at how the natural ventilation works.”
The beauty of the building itself is not the only thing generating positivity for staff, Harris says. As the work of the GCI is directly counter to the current federal and Queensland state government stances on climate change, the “local action” of being in a low carbon, net zero building helps keep morale up.
“We are certainly doing something about [climate change],” Harris says.
UQ have one of the largest solar arrays in Queensland on the campus, and are looking to put in a showcase multi-hectare array.
Harris says everyone at the university is convinced we are “facing a very different future” where energy-intensive industries “won’t be able to cover up costs”.
This is where the GCI’s example of how economically viable sustainable building can be holds great value. The project, leading-edge as it is, cost $32 million. Its operational costs are extremely low, with rainwater harvested and stored for amenities, kitchens and the hydronic cooling and heating system, also for irrigation of plantings including a bush tucker garden. It has no mains grid power-use bills.
“More sustainable building [techniques] is a major decrease of the wider society’s carbon footprint,” Harris says.
He says there needs to be a cultural shift in the residential sector in particular.
“Most people want more control over their indoor environment than what their actual needs are,” he says. “This technology [used in the GCI] is very applicable to residential dwellings.”
“We deal a lot in the bigger picture.”
Design lessons learned
Director and principal structural engineer at Bligh Tanner Rod Bligh, who worked on the structural, civil and facade engineering for the GCI, says the biggest lesson of the project was the process of design and construction itself and the way a team can bring innovation into a project.
“It’s partly the effort you put into researching what’s possible,” he told The Fifth Estate. “It’s more effort than the easy [conventional] route.”
The project was a full collaboration with everyone aboard from the initial stages including the client, he says. The geopolymer concrete, for example, needed to be tested in sufficient time for it to be proven fit for purpose by the time it was required by the construction program. Bligh says they had a plan B to fall back on, just in case.
“Geopolymer concrete will be easier to use a second time round,” he says.
“There was also a lot going on with building services and the different modes of cooling, and the operable sunscreen was another big thing for us, making it work in a neat way. It had to be able to withstand windloads as well as be continuously moving and involving motors and gears – that was a lot of research.
“The sunshades will be looked at by other people [for inspiration].”
One of the key technical difficulties in terms of their engineering was not having “a whole lot of equipment exposed”.
The German system that was used was modified by Bligh Tanner around the housing to hide much of the working parts.
A story of teamwork
“The GCI is a story about teamwork and the client,” Bligh says.
One of the issues he raises is that under Green Star rules, operable components do not score points in the same way that automated systems do.
“The issue with operable components is they need to have people that want to operate them,” Bligh says.
In the GCI, the main operable component is the one occupants can control – how they dress. Bligh says their comfort level mainly comes down to dressing accordingly.
In the big picture of green design and construction, Bligh observes that there are “a whole lot of buildings that haven’t worked”.
UQ itself has experimented across a number of buildings with different modes of passive cooling, some of which succeeded, some of which didn’t.
In the GCI’s case, Bligh says the mindset at the outset was “this is an experimental phase”.
“If it doesn’t work 100 per cent, that’s almost to be expected. This team tried to be very accountable.”
Significant fine-tuning required
HASSELL principal Mark Roehrs, the lead architect on the project, says the complexity of the building in terms of all the interacting systems had resulted in a need for a significant amount of fine-tuning.
At the same time, the response from people in the building has been positive. It is also drawing staff, students and visitors from around the campus to spend time there, particularly around the atrium with its green wall.
“The feel of a naturally ventilated space is quite rewarding,” Roehrs told The Fifth Estate.
“Being in open mode for 88 per cent of the year we are really pushing the boundaries [with people]. We are saying to them comfort is 18 degrees to 28 degrees.”
Roehrs says making 28 degrees comfortable requires enacting “all seven modes” of thermal comfort – optimising air temperature, controlling humidity, controlling solar radiation and radiant heat, dressing appropriately, engaging in an appropriate level of activity, optimising fresh air and managing airflow.
“It does require participation from individuals in their environment. For example, they need to come dressed for fact it may be cold or hot in the office.”
The only time the building is closed and sealed, and the mechanical cooling or heating used, is when it is very cold or very hot.
“The users were emphatic on not having airconditioning [most of the time]; they did not want a conventional system.”
The building’s chilled water system is used to cool the building at night so it is not radiating heat, with cool also retained in the primary structure.
Roehrs says the idea of sustainability as implemented in the GCI is not just about the physical performance but also about the design quality and social qualities of the building.
“We will see these emerging as key themes of sustainability in future,” he says. “Discussions about space contribute to social sustainability, and the beauty and quality of the work environment.”
“The building is really set up so with various systems it can be used as a research tool to modify conditions and run those [kinds of] research studies. Participants in the building can modify airflow from the hydronic cooling system, so there is the potential to really collect data that could give big insights into subtropical environment and the conditions for sustainability.”
Roehrs says that the initial brief from UQ was it wanted the building to be “next generation” and “cutting edge”.
“We said, ‘What’s that?’”
Roehrs says the final GCI concept revolves around the idea buildings can move from being “consumers” to “participating in the environment”.
Again, the inhabitants have a role to play, with Roehrs saying they need to actively participate in the achievement of the net zero goal by managing their individual energy consumption.
“It is very rarely that you get the opportunity to research and apply research in the way that we have [at the GCI]. For example, the geopolymer concrete; this was the first time it was used [structurally]. Hopefully that will get out in the market – the influence that would have on carbon emissions throughout the world would be really massive.
“If we have the opportunity to use it again on a project, we would.”
Another area where the project has delivered useful insights is in airflow, and how to manage the acoustics between teaching spaces and office spaces with the level of cross-ventilation and with the airflow controlled by the plenum.
Computational fluid dynamics were used to model airflow and acoustics, and Roehrs says that every time the practice goes into the modelling space for a project using CFD, it is learning lessons about how it can be applied to the next project. The same is true of the thermal chimney, which is not the first the practice has designed, but is a concept that is being refined each time.
The project has a two-year defects liability period, and Roehrs says the team will continue to attend the site regularly and carry out fine tuning and ongoing commissioning for the full two years.
“The consultant team and contractors made an enormous commitment to this project,” he says.
Roehrs says that in addition to universities showing an interest in sustainability initiatives that have campus-wide benefits, they will often only get one or two buildings Green Star certified, before deciding to invest the cost of certification of further projects in greater initiatives.
“The other very interesting thing, that is a very significant mind shift happening in universities, is the one from looking at buildings needing to be low maintenance, so you don’t touch them for 15 years, to recognising low energy building systems are complex, and they will need adjustments in control systems and maintenance, so they need a higher commitment to maintenance.”