Towards Zero Carbon

Architectus echoes Macquarie University’s Sustainability Framework, recognising ‘that sustainability is both an exciting journey and an essential destination.’ The University is responding to the projected needs of their community and taking an environmentally conscientious approach, which Architectus takes seriously – with a long history of environmentally sustainable design demonstrated by Green Star achievements, awards, and a National Leader of Urban Futures and Resilience who ensures that each project meets carbon reduction goals and sustainability targets.

Increasingly, Architectus has been exploring and expanding its intelligent use of sustainable materials. In November 2019, we took part in focused industry research that demonstrated, in a bushfire, that rammed earth is capable of withstanding temperatures of over 1000°c with minimal heat transfer. As a result, we have specified this low embodied carbon material to construct vaults that will safeguard irreplaceable plant specimen collections at the National Herbarium of NSW at Mount Annan, which has been co-designed with architect Richard Leplastrier. Many experts argue that timber also has advantages in case of a fire, which after the devastating Australian bushfire season of 2019-20 should be at the forefront of our collective minds. Timber burns at a slow and predictable rate, while the integrity of a load-bearing steel structure precipitously declines when its temperature exceeds about 400°c. Steel is also prone to buckling when significant temperature variations occur throughout the structure.

By virtue of its use of timber, the Incubator has strong sustainable features. Provided it is grown in sustainable forests and logged at optimal maturity, timber sequesters enormous quantities of carbon (1 tonne of timber withholds 1.8 tonnes of carbon dioxide from the atmosphere). Carbon dioxide is only released if it burns or decomposes. In addition, the building itself is fully recyclable by design because it can be disassembled and repurposed easily in a different location. Inside, the space can be mixed mode or naturally ventilated. It is self-shading and generates electricity through photo-voltaic arrays on the rooftop. It captures rainwater to redistribute it back through the surrounding landscape. Its passive design mitigates the solar load onto the glazing which reduces its need to draw upon energy from mechanical systems.

While the Incubator set the standard for mass timber construction in a ‘temporary’ space, the Ainsworth Building – another mass timber building – is an evolution of this concept in a permanent structure that reflects the ambitious sustainability goals that are outlined in Macquarie University’s Campus Master Plan. Containing 700 tonnes of timber, project engineers Arup calculate that this will save the carbon emission equivalent of five-to-six years of energy consumption during its operation.

Following the success of the Incubator’s construction, the Ainsworth Building – where future medical and health professionals will acquire knowledge to deliver world-class services – was also prefabricated meticulously offsite, with each section arriving just in time to be slotted into place, making for rapid assembly onsite. Not only did this significantly reduce the energy load during the construction period, but it also meant the waste onsite was decreased and far fewer vehicles were needed, making the construction relatively quiet and clean, which helped the existing buildings that surround the Ainsworth Building on three sides, including a functioning hospital with operating theatres. Wherever possible, Victorian Ash – a local Australian timber – was sourced to avoid the large energy consumption of materials being transported from overseas, which also contributes to a more sustainable project and helps the local economy by supporting local production. Unlike a more common building site, dealing with steel and concrete, working with timber was uplifting for the builders, as it is for the occupants.

Beyond the construction process, the completed structure features smart ways to reduce energy. The 28-kilowatt photovoltaic system supplies between 10-20 per cent of the building’s energy. The double-glazed glass façade maximises natural light, reducing the need for lighting during the daytime and heating during the winter, and the automated blinds provide solar protection and glare control. The natural and mixed-mode ventilation on the entry level improves the air flow and reduces energy consumption. The low temperature variable air volume system maximises cooling and is modulated according to how many people are using the building. Additionally, this system includes louvres at the bottom and top of the atrium which can be used at night to the purge any heat stored throughout the day. Outside, the landscaped spaces along both Innovation Road and Wally’s Walk rejuvenate the area.

The biophilic qualities of the honey-coloured timber frame creates a tangible connection to nature, a stimulating environment in which to learn, and a sense of warmth, calm, and wellness from being surrounded by natural elements. The evidence is abundant from the inhabitants of the Incubator – who thoroughly enjoy spending time in an environment that is warm, offers fresh air, abundant light, and views over the woodland campus – so the University looked to replicate this atmosphere in the Ainsworth Building. The wood provides both structural integrity and much of the internal skin. W-shaped hardwood columns at the entrance are a defining feature that transfer vertical loads to the ground. A double-glazed glass façade reveals the timber structure’s clear geometry and draws optimal daylight into the interior spaces. Within, the timber gives a cohesive and welcoming tactility across the various learning spaces.