The challenge
Mirvac's Sydney assets don't share a plant design. Angel Place at 123 Pitt Street runs four PowerPax chillers of unequal size, one at 720 kWr and three at 1,700 kWr. 400 George Street runs three York centrifugals and one PowerPax. 8 Chifley Square runs two magnetic bearing York units. Building 1 at South Eveleigh runs three chillers across five staging levels.
They don't share a controls stack either. Honeywell at 400 George Street and Johnson Controls Metasys at 8 Chifley Square, with different data platforms again for telemetry: Switch Automation at Angel Place, and Bueno at 8 Chifley Square and South Eveleigh.
What they did share was the usual cause of avoidable energy use in a well-run building. These are high-performing assets with strong NABERS ratings and competent facilities teams, and the plants were still sequenced on fixed thresholds with condenser water setpoints that didn't track ambient conditions. Good buildings, conservative controls.
None of the four required new hardware. Every strategy was delivered as setpoints for the building's existing controls contractor to implement.
Portfolio profile
Verified results
Asset-by-asset measured performance
Each plant was verified over its own reporting period against its own baseline, using a regression of plant energy against measured cooling load. The kWh and carbon figures below are the savings measured within each site's stated window and aren't annualized, so they shouldn't be summed into a portfolio annual figure. Carbon uses 0.80 tCO2/MWh, the factor in each M&V report. No cost savings are reported for this portfolio.
| Outcome | Verified result | Status |
|---|---|---|
| 400 George Street energy saving | 21%, with 53,780 kWh and 43.0 tCO2 saved over a 123-day measurement window (R² 0.84) | Verified |
| Angel Place energy saving | 9.4%, with 33,240 kWh and 26.6 tCO2 saved over a 265-day reporting period (R² 0.995) | Verified |
| South Eveleigh energy saving | 12.4%, with 14,160 kWh and 11.2 tCO2 saved | Verified, preliminary |
Verified: measured through M&V against each site's own baseline. Preliminary: reported over the measured window rather than a full 12-month result.
In progress
8 Chifley Square, modeled and awaiting verification
| Outcome | Modeled result | Status |
|---|---|---|
| 8 Chifley Square energy saving | 16.4% modeled, with 47,493 kWh and 38 tCO2e modeled saving across a 2,350 kWr plant | Modeled |
Modeled: this is a forecast from the site's digital twin and hasn't been through measurement and verification yet.
The Exergenics approach
One method, four very different plants
Take the data the building already produces
Chiller, pump and cooling tower trends came through whichever platform the asset already ran, by API from Switch Automation at Angel Place and from Bueno at 8 Chifley Square and South Eveleigh. Nothing was installed to collect data that was already being collected.
Model the plant, not the building type
A digital twin was built for each plant from its own operating history. Four PowerPax chillers of unequal size and two magnetic bearing York units present different staging problems, and a strategy generated for one would be wrong for the other.
Bound the strategy with site knowledge
Facilities teams supplied the constraints that don't appear in trend data, including which sequences are off limits, which plant is unreliable and which readings to distrust. Recommended setpoints stayed inside the parameters the existing BMS already permitted.
Hand it to the incumbent contractor
The strategy was issued as setpoints and sequences and coded in by the controls contractor already responsible for the building. No Exergenics hardware sits on any of these sites and no connection to the control network is maintained.