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In the heart of Sydney’s Central Business District (CBD) stands a prestigious high-rise building that has just undergone a significant HVAC upgrade.

Built in 2004, the 54-floor building is one of the biggest in Sydney’s mid-town precinct, with over 62,000 square metres of office space.

The project involved several key upgrades designed to future proof operations while also delivering productivity and environmental benefits.

The project scope identified that a significant efficiency dividend could be gained by upgrading the two Carrier Centrifugal - AQUAEDGE 19XR chiller systems from legacy fixed drives to more energy efficient Variable Speed Drives.

This undertaking posed some unique challenges for project partner Carrier and their supplier Eaton. 

On the top floor, high above the city skyline, sits the chiller plant room which houses the two Carrier chiller systems that service the building.                            

NSW modernisation manager at Carrier, Sam Sayed, said modifying the existing chiller system was the best way to drive efficiency gains.

“However, to do that we needed a product that would be small and easy to install,” he said.

In many large commercial buildings in NSW, chiller plant rooms are often located on the top floor or roof of the building which makes accessibility a challenge, especially when machinery is due for replacement.

In this instance, installing a brand new 4,000-kilowatt chiller in a building like this was deemed nearly impossible. With cranes unable to reach that height, it would have required a costly rigging solution that was unfeasible.

“To completely replace a single chiller, the only option was to substitute it for two smaller systems at a very large expense.,” Sayed said.

“The most effective option was to modify the existing chiller systems from a fixed speed drive to variable frequency drive.”  

The next challenge was finding a VSD that could be easily transported to the top floor by service elevator and fit in the plant room. Some freestanding products were physically too large, so Carrier widened the search.

After working closely with Eaton Australia’s local team and factory in the United States, Carrier decided that Eaton’s LCX9000 refrigerant-cooled drives would best meet the unique requirements of the project – and deliver the desired energy efficiency outcomes.

“We modelled the cost and energy efficiency outcomes of retrofitting the two chiller systems with Eaton variable speed drives and found it could achieve up to 47 per cent in energy and cost savings – with an ROI of just under three years for each chiller,” Sayed said.

Eaton’s LCX9000 drives are compact in size, with low heat transfers that allow the enclosure size to be greatly reduced. The highly reliable liquid-cooled product offers 500,000 hours of mean time before failure (MTBE) and can remove up to 95 per cent of heat generated.

To ensure a seamless chiller interface system and smooth commissioning process, Eaton customised its drive software to map the Carrier configuration points. This allowed the Carrier PIC-5 controller to communicate easily with the drive via the UPC Modbus Gateway.

Carrier delivered the turn-key project over one month, converting the two chiller systems and installing the drives.

Each drive was supplied in two parts by Eaton and reassembled by Carrier to ensure it could be easily transported and installed in the plant room. This was the first time Eaton had supplied this product in two parts.  

The LCX9000 drives were assembled adjacent to the chiller on a steel frame to provide easy access for future maintenance. Eaton engineers were on hand to support the commissioning of each system.

The project has allowed the property group to future proof its building and maintain its 5 Star NABERS Energy Efficiency Rating.

“As a rule of thumb for commercial buildings, chillers usually come to 40 per cent of the total electricity bill, so this upgrade was quite significant in the overall renovation works,” Sayed said.

Since upgrading the two chiller systems, in-rush current has dramatically reduced which has given operators more confidence in handling peak demand.

Comparative analysis of the cost and energy efficiency outcomes modelled by Carrier is ongoing, with return on investment and energy use reductions on track. 

 

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