by Lynne Blundell
FAVOURITES – 21 April 2010 – Carbon neutrality, the sustainable holy grail for buildings, is likely to remain just as elusive as that legendary object unless those who design and operate them up the ante. This was the message in a session on carbon emissions at the Australian Refrigeration and Building Services conference held in Sydney last week.
Convener of the session, executive director of the Green Star rating system, Robin Mellon, told delegates that while many facilities managers had a carbon neutral target for their buildings by 2012, most had no budget and no idea how to achieve it.
There were a variety of options for buildings to reduce emissions including balancing carbon released by using renewable energy or offsetting emissions through carbon credits or sequestration.
But it was time to start thinking differently about the way buildings operate and to embrace technologies that allowed them to create energy, whether through co- or tri-generation or renewable technologies.
“We need to look at buildings as producers, not just consumers of resources,” said Mellon.
The Green Building Council of Australia and its Green Star rating system is working with other international ratings tools such as BREEAM in the UK, LEED in the US and CASBEE in Japan to find a common carbon metric for buildings, said Mr Mellon, whether through the measurement of carbon emissions or greenhouse gases.
Attitudes must change
But the main message from other speakers in the session was that a major shift in attitude of both building designers and users was vital.
Caroline Pidcock, principal of Pidcock Architects, pointed out that with residential and commercial buildings responsible for 23 per cent of Australia’s carbon emissions (ASBEC 2007 study), striving to design low carbon buildings was vitally important.
“A quarter of our emissions come from operating buildings, with heating and cooling accounting for one third to half of this,” said Ms Pidcock.
To reduce this, architects need to think more about designing buildings for the climate and location in which they are situated. There should also be more emphasis on the psychological comfort of the occupants.
“Psychological comfort is very important – people want to be able to control the excesses of heat and cold but occupants also need to engage positively with the environment. Buildings need to be designed to be adaptive,” Ms Pidcock said.
As perceived comfort varied considerably, architects needed to understand the people who used the building, their needs and their activities.
Design strategies to reduce carbon emissions and energy use included:
- internal conditions should vary in parallel with, and be appropriate to, the external environment
- flexibility and adaptability for occupants now and into the future
- enhancing thermal comfort by allowing the building to respond to visual clues outside
- design should be easy to use with intuitive systems
- passive design by maximising the site and climate is very important
Too often buildings were homogenous and could be in any city in the world, with designs from Hong Kong to Australia to Europe varying little despite the vastly different cultures and climates.
Simple changes in peoples’ behaviour could also have major impacts, said Ms Pidcock, citing Japan’s 2005 Cool Biz campaign which encouraged men to stop wearing neckties.
“Necktie sales fell 35 per cent which didn’t make the necktie companies very happy but at the same time there was a massive drop in CO2 emissions and energy use.
“Ultimately a low carbon future depends on personal decisions.”
Shane Esmore, director of building services and sustainable engineering consultancy, Umow Lai, said more emphasis on the total lifecycle impact of buildings was needed.
“Embodied energy of the building needs to be accounted for. Passive design is a starting point but it doesn’t end there,” Mr Esmore said.
“We have to look at the construction materials used. And we can’t get away from renewable energy.”
Mr Esmore presented case studies of buildings that were pushing the envelope, including Grocon’s Pixel building in Melbourne (see our story on this) and the Vanke Tower in Dongguan, China.
The Pixel building, the first stage of the CUB Site redevelopment, has set itself to become the highest performing sustainable office building built in the world to date, aiming to achieve a carbon neutral status by offsetting all of its operational and embodied carbon emissions.
The building is registered for Green Star Office Design rating (World Leader) and is aiming to achieve all credit points available to it. It is also intended to rate the building under the LEED and BREEAM tools to establish the highest point scores to date under these rating tools.
Umow Lai worked with Grocon on the building, providing services engineering and sustainable design advice.
A true carbon neutral building, Pixel makes maximises sunlight and incorporates features such as low energy lighting, heat exchange with underfloor system and gas-fired heat absorption pump as well as renewable energy technology, including wind turbines and fixed and tracing solar photovoltaic panels.
Additional ESD features include a green roof with extensive planting of indigenous grasses, rainwater capture and use, vacuum toilets and anaerobic digester which utilises methane to fire the hot water system. Wetlands have been created around the building to recycle grey water.
“There is a focus in the building on materials used and embodied energy. The building doesn’t have many of the things that normal buildings do – for example there are only two fans – one to supply and one to extract. There is also one very small, efficient lift,” said Mr Esmore.
In another project cited by Esmore, Vanke, the largest residential developer in China selling 6.6 milion square metres of property in 2009, had used a large installation of “prayer wheel” wind turbines to generate thermal power.
Management can work wonders
But it is the management of buildings where Craig Roussac, sustainability manager with Investa, sees the most potential for a low carbon future.
“There is not nearly enough emphasis on managing buildings,” Mr Roussac told delegates.
Investa has embarked on an ambitious project to get its large portfolio of commercial properties, representing 1.4 per cent of the Australian market, operating to 4.5 Star NABERS rating. Currently the portfolio had a 4 Star rating, up from 2.5 stars in 2003/04.
“We need to get the whole portfolio up to 4.5 Stars because that’s what people who care about these things want,” Mr Roussac said.
On one of its buildings Investa had achieved a 50 per cent reduction in energy consumption and was aiming for 60 per cent. Half of this had been achieved through technology and half through better management of the building.
“The important thing is to get people to care,” said Mr Roussac.
A difficult aspect of improving a building’s energy performance was the reaction of occupants to perceived differences in the internal environment. This could have a counter intuitive effect on occupant satisfaction.
“When we told staff in one of our buildings that we had adjusted the temperature complaints increased because they became more aware. People expect very controlled temperature in office buildings but are happy with 28 degrees at home,” he said.
Investa had used green leases with its buildings for some years but one area that always caused problems was building temperature, with lawyers resisting change in this area.
Recently, Investa had possibly put its whole portfolio in breach of these leases by slightly reducing the temperature across the portfolio, said Roussac.
“We took the view nobody would notice. Lawyers are listening to engineers and they want the status quo maintained.”
Shane Esmore agreed, saying there needed to be a cultural shift when it came to the “comfort equation”.
“Pixel wanted natural ventilation but it clashes with Green Star requirements,” Mr Esmore said.
When questioned on this point after the session, Mr Esmore explained to The Fifth Estate that natural ventilation in the Pixel project had encountered obstacles because of the way Green Star penalises this approach. Pixel had some automated opening windows but these were designed primarily for passive night purge. As soon as natural ventilation was used in normal mode the project encountered problems under Green Star ratings, including:
- inability to meet acoustic criteria due to external noise
- inability to meet individual comfort control criteria due to restrictive requirement of 0.75 sq m opening accessible to each occupant
- complications in the demonstration of air change effectiveness
- only a very minor energy improvement due to the already extremely low energy design of the ventilation
- major issues with achieving the thermal comfort criteria that effectively limits the energy savings possible
Mr Esmore said that Green Star imposes extra requirements and effectively penalises projects wishing to use natural or mixed mode ventilation, something that does not occur to the same extent with other tools such as LEED or BREEAM (BREEAM was the opposite).
“We have to get smarter and more holistic. It is not just about energy or comfort or materials – it is all three,” Mr Esmore told delegates.
And Craig Roussac finished the session with this observation:
“Technology has a seductiveness that has dominated the industry for decades. We have entered a period where we must engage users and operators of buildings.”
The Fifth Estate – sustainable property news and forum