Right on Q

Image: Atlassian The architectural design organises the interior into seven interconnected, four-level “habitats”. Each “habitat” is then divided into three distinct climate zones to reduce the demand on mechanical air conditioning and heating.

The sustainable, energy efficient design of Atlassian Central aims to:

• Achieve a 50% reduction in embodied carbon in construction for facade, substructure and super structure compared to a conventional construction project.

• Consume 50% less operational energy compared to a conventional building.

• Be powered by 100% renewable energy from day one of operation.

• Target 5.5 star NABERS Energy Commitment Agreement and 6 star Green Star design rating.

• WELL Platinum Core rating.

• LEED Platinum rating.

Located within the NSW State Government-led Tech Central precinct and adjacent to Central Station, the 39-storey tower is expected to be the world’s tallest commercial hybrid timber building when completed.

Designed by SHoP Architects in partnership with local firm BVN, Atlassian Central’s mass-timber construction will be supported within a glass and steel exoskeleton that incorporates an electricity-generating façade system with shading capabilities to minimise solar heat gain.

Built – in a joint venture with Obayashi Corporation (BOJV) – have been appointed by developer Dexus to construct the building.

BOJV were engaged as part of an early contractor involvement (ECI) agreement in May 2020 to work with the Atlassian development team, architects and consultant team on the design. This early engagement saw A.G. Coombs assist BOJV to work through the early concept mechanical services design by consultant LCI, before A.G. Coombs collaborated with LCI in documenting the design in 3D modelling.

Having developed a strong understanding of the project through this process, A.G. Coombs was subsequently invited by BOJV to tender for the mechanical services design and construct (D&C), and awarded the project in 2022.

“The unresolved design featured a number of environmental aspirations, so our team has worked to valueengineer the mechanical services solution to achieve these within the build price,” says Ryujin Lee, Senior Design Engineer with A.G. Coombs.

The architectural design organises the interior into seven interconnected, four-level “habitats”. Each “habitat” is then divided into three distinct climate zones to reduce the demand on mechanical air conditioning and heating, and thereby reducing energy consumption and associated greenhouse gas emissions.

The three-level outdoor garden zone, closest to the operable façade, will be naturally ventilated and takes advantage of Sydney’s temperate climate.

The middle office zone will have access to natural ventilation from the outdoor zone as well as mechanical ventilation. The interior office zone closest to the building’s core will be mechanically conditioned, but has been designed with a higher-thanusual operating temperature band of 24˚C - 26˚C. Passive radiant (chilled) beams and ceiling fans are intended to provide occupant comfort at these higher temperatures.

The radiant beams are named so for their ability to provide both radiant cooling and heating. As such, they will also be used to provide perimeter heating, and have undergone comprehensive laboratory testing and benchmarking by A.G. Coombs using overseas examples.

The hybridity of systems serving Atlassian Central means much of A.G. Coombs’ work to date has centred on the validation of thermal comfort within the occupied spaces, and the development of a complex dehumidification strategy.

“Our early engagement certainly helped the team to develop a strong assessment of the conceptual mechanical services design,” says Ryujin. “Our work to date has been around ensuring these aspirations are achievable from a build perspective.”

Limited spatial availability, and the requirement for services to be exposed as a consequence of the building’s mass timber construction, has also seen the A.G. Coombs team work collaboratively with the architects and structural engineers to identify suitable solutions.

Similarly, an innovative solution is required to ensure the rooftop mechanical services plant does not impact the shadow line created by the diagonal cut of the high level façade – one of the building’s unique architectural features.

Only on the top four “crown” floors will the mechanical services design reflect a traditional solution, with centralised plant serving multiple air handling units (AHUs).

Construction of Atlassian Central commenced in the second half of 2022, with completion expected by 2027.

“While the client rightly sets the sustainability vision for the project, builders and contractors play an active role in realising that vision,” says Jared Brookes, Services Manager at Built.

“Given the sustainability aspirations of the Atlassian Central project, BOJV has selected key partners whose expertise will positively influence the sustainability outcomes. We look forward to the contribution A.G. Coombs will make to this world-leading project.”