IAG House, originally completed in 1976, has been transformed into an energy-efficient building, standing tall in the centre of Sydney.

Undertaking the second refurbishment of 388 George St in its lifetime, Brookfield and Investa upgraded many of the inefficient systems throughout the building.

Completed in 2010, upgrading the 28-storey office building was important to Brookfield as it is committed to improving energy performance of existing buildings just as much as new buildings.

During the refurbishment, tenants remained in-situ on every floor, meaning the project team had to develop a raft of innovative and sustainable solutions to overcome this significant challenge. One of those, rather than replacing the existing HVAC system, was reviewing the existing system with the aim to maximise its operational and serviceable life. In turn, this reduced new material consumption and disposal of otherwise serviceable items.

The main aim of the refurbishment was to reduce consumption and waste. New energy-efficient lighting was installed in common areas, along with a new building management system, variable speed drives to motors, and the refurbishment of the air handling system dampers to achieve greater energy savings and less wastage.

Waste was also reduced by updating existing machinery. For example the fan blades in the cooling towers were replaced with adjustable blades, which reduced the energy output of the cooling towers.

Additionally, Variable Speed Drivers were installed or upgraded to new technology, for all fans, pumps and motors to ensure mechanical equipment operates at its optimum level rather than running at 100% all the time. A CO2 monitoring system was also installed through the air handling system, so as to improve the air quality provided to occupants.

A new Building Management Control System (BMCS) from Schneider Electric balanced heating comfort levels on occupied floors. Old pneumatic controls were replaced with smart electronic actuators and motors, which allowed Variable Air Volume Boxes (VAVs) to deliver maximum and minimum air volumes to occupants.

Finally, Motorised Volume Control Dampers (MVCDs) were installed on each floor to allow direct channelling of air supply to occupied floors, while avoiding air circulation to empty floors.

This ability has resulted in massive energy savings. For example, the air-conditioning can be channelled to one level and air circulation can be avoided to empty floors. Dampers will prove beneficial in future renovations, as levels can be closed off when they are carried out to avoid the spreading of fumes and disruption to other floors.

With all these upgrades, comfort levels in the resulting building have been improved drastically with less day-to-day intervention by building management and contractors, says Jamie Loader, Brookfield Office Properties National Operations and Sustainability manager – commercial operations.

“The BMCS is constantly altering the operation of cooling and heating systems to provide best comfort to tenants, all while achieving the most environmentally and cost efficient running of its plant and equipment,” Loader says.

The resulting energy savings from the renovations stands at 1.2 million kWh every year, or a reduction of 52.7% on the 2008 consumption. This translates to taking 320 family cars off the road, Loader says.

IAG House has since achieved a 4 Star Green Star – Office As Built V2 rating as well as a 4.5 star NABERS Energy certified rating.

Schneider Electric Building Management Control System (BMCS)

A Schneider Electric BMCS was installed in order to control air supply to various floors.

Essentially, it is the brain of the building – able to intelligently control the many systems and thousands of data points throughout.

An integrated approach unifies multiple systems on one network, from a single software platform. Data from all systems is incorporated and converted into information that can enhance efficiency, comfort and well-being for building occupants and owners.

A building management control system can incorporate security, HVAC, access control, video surveillance, lighting control and energy efficiency.

The Andover Contiuum, as used in IAG House, can be built from the ground up as a monitoring and control system for building climate and security, reducing the amount of wiring and hardware needed.

Lisa Rapley

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