A chiller plant upgrade and the addition of an award winning controls system has breathed new life and energy efficiency into one of Melbourne’s most iconic financial district buildings, ANZ’s 100 Queen Street.
Australia’s existing commercial office building stock is often referred to as the sleeping giant in this country’s efforts to reduce the impact of our buildings on the environment and greenhouse gas emissions.
Building’s aged between 20 and 40 years offer enormous opportunities for energy efficiency improvements due to their large numbers, and the typical upgrade cycles of mechanical equipment.
ANZ world headquarters at 100 Queen Street Melbourne is one such building.
Constructed in 1993, the 37-storey commercial office tower is solely occupied by ANZ and managed by facility manager Jones Lang LaSalle (JLL).
Since late 2012, Airmaster Australia has provided service and maintenance for the site and worked closely with JLL on improving the building’s energy performance and NABERS Energy rating via efficiency upgrades to the building’s main chilled water plant.
This led to the installation of the award-winning PlantPRO control system in December 2014.
Winner of the AIRAH Product of the Year Award in 2015, PlantPRO provides control of the chiller plant system in a way that delivers efficiencies beyond that of the individual components.
Engineered and developed by Melbourne-based company Conserve It, the optimisation and control software solution uses feedback from its on board real time analytics, diagnostics, measurement and verification systems to continually re-adjust the chiller plant for optimal performance without the need for proprietary tools.
Chiller plant upgrade
When it came time to upgrade the building’s aging main chilled water plant, over six months of data collected by PlantPRO was used to help plan the project.
One of the great advantages of PlantPRO on this project was that it was significantly better at collecting data than the building’s existing BMS.
And without data, you’re working in the dark.
The load data collected by PlantPRO was used by Arup to determine if the constructions staging of the chillers would work. Through this process, greater confidence in the program’s abilities was built.
The upgrade included two new chillers, all new pumps with sensors installed to control the variable speed drives; and new cooling towers. Temperature, flow and pressure meters were installed to provide data to PlantPRO as well as the BMS.
During the project, PlantPRO’s intelligent optimisation was used to maintain conditions. It was able to produce over 1200kW of cooling out of the two existing, low-load chillers that had a combined nominal rating of 1090kW.
This was achieved by driving the chillers into “off design” conditions, but at the same time carefully monitoring their performance to ensure they remained within safe operating parameters.
According to JLL’s Hamish Stevenson, PlantPRO proved itself to be a critical enablement tool during the upgrade works.
“PlantPRO’s data and reporting provision, as well as the system’s ability to drive performance exceeding plant capacity, enabled the project team to deliver the upgrade during less-than-ideal temperature conditions, and during a compressed period for both the data gathering for design as well as overall delivery,” he says.
“It was generally felt that without PlantPRO both prior to and during the project, the delivery team would have been severely impacted.”
Smart sequencing
According to Airmaster Project Manager Phil Barrow, 100 Queen Street’s existing BMS is now only used to initiate the new chiller plant’s start up.
“Once the chillers are operating, PlantPRO takes full operational control of the chiller plant from the BMS, to maintain efficient operation and optimal internal temperatures,” he says.
Using smart sequencing, PlantPRO optimises the plant by running the most efficient combination of chillers for the given conditions.
Accordingly, it selects the most efficient load point for each running chiller. If a chiller operates below its nominal efficiency, it can be proactively checked by service personnel to minimise electrical energy waste and avoid compounding service issues that can result in costly repairs.
Energy efficiency is also achieved through advanced variable pumping control and lift optimisation on the refrigerant side.
Since the plant upgrade, average monthly energy savings of approximately 30 per cent, have been realised.
PlantPRO has also delivered other benefits, including a reduction in plant running hours and more efficient chilled water (CHW) flow due to its ability to tune the by-pass loop more effectively.
“(It has delivered) more efficient staging during the morning peak,” says Nicholas Giannoulakis, facility manager for JLL at 100 Queen Street.
“There’s no long delay in staging up to high loads – achieving and maintaining temperature set points earlier. And PlantPRO’s daily reports and logs were beneficial to diagnose faults.”
Additionally, a reduction in temperature complaints has been recorded.
The energy performance of 100 Queen Street continues to be monitored.
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