In a mission-critical data centre, cooling is not just about comfort. It is fundamental to keeping digital services online, protecting equipment, and maintaining service level agreements. Any unexpected loss of cooling can have serious commercial and operational consequences.
At one major Australian data centre, the operator recognised that its existing chiller control system needed a step change. The site required an upgrade that would modernise the control architecture, remove single points of failure, and provide better visibility of chiller performance. All of this had to be delivered without any interruption to data centre operations.
The operator engaged SAGE to design and deliver a new control system for the chiller plant at one of its flagship facilities. The objective was clear: create a highly resilient, fully redundant control environment that would support reliable cooling today and into the future.
The project focused on upgrading the chiller control system to improve reliability, resilience and ease of operation. It also needed to integrate seamlessly with existing chillers, plant equipment and the Schneider building management system, and align with the operator’s strict control philosophy and sequencing standards. The work was executed with zero downtime, ensuring the data centre remained fully operational throughout.
SAGE designed a robust control system architecture tailored to the demands of a mission-critical data centre environment. At the core of the solution was a fully redundant control platform that removed previous single points of failure and introduced multiple layers of protection.
A new main control panel was supplied with dual 230 volt alternating current feeds powering redundant 24-volt direct current power supplies. The panel housed ControlLogix 5580 processors and a human–machine interface built using approved symbols and faceplates, providing operators with a familiar, consistent interface.
Chiller 2 PLC Panel Internal
Resilient cooling in a data centre depends not only on robust central controllers, but also on distributed control and high-quality field data. To support this, SAGE implemented a distributed control approach across the chiller plant.
Three remote point input/output panels and four CompactLogix programmable logic controller panels were integrated, with each panel managing individual chiller strings in accordance with site-specific sequencing standards. This distributed architecture enhanced flexibility and supported precise control of each chiller string.
To further strengthen reliability and fault tolerance, triplicated input/output cards and field instrumentation were deployed. These were split across the remote input/output panels so that a failure in one device or panel would not compromise overall system performance. This triplication extended to key chilled water measurements, including supply and return temperatures, flow and differential pressure.
The project also ensured that the upgraded control system worked seamlessly with existing plant and monitoring platforms. Existing chillers were integrated into the Schneider building management system, preserving the operator’s established monitoring environment while enhancing control and visibility.
Dedicated chiller control panels were built, installed and commissioned for each chiller. Chiller instrumentation was wired back to the chiller input/output panels, providing accurate, reliable data for control and diagnostics. Danfoss variable speed drives were upgraded to enable remote monitoring, improving insight into drive performance and supporting proactive maintenance.
Additional monitoring was incorporated to give the operator a richer picture of plant conditions. Triplicated chilled water supply and return temperature transmitters were installed on each riser, along with triplicated Siemens magnetic flow meters on supply risers and differential pressure transmitters. Together, these devices provided detailed, resilient feedback to support optimised control and early fault detection.
One of the most significant changes was the removal of a critical single point of failure in the original control system. Previously, a single commercial controller was responsible for chiller sequencing across the plant. If that device failed, the sequencing function would be compromised.
In the upgraded design, sequencing is managed by industrial dual redundant ControlLogix programmable logic controllers. This shift to industrial-grade, redundant control dramatically reduces the risk of loss of sequencing and supports continuous, reliable cooling even if one controller fails.
The upgraded control system now meets all of the data centre’s standards and delivers a marked improvement in reliability, operational efficiency and remote monitoring capability. The enhanced redundancy in both power and control, along with triplicated instrumentation, reduces operational risk and provides stronger protection against unplanned outages.
Improved visibility of chiller and chilled water performance helps operators make better decisions, optimise plant operation and identify issues earlier. Integration with the existing building management system ensures a smooth operator experience and maximises the value of the operator’s existing platforms.
The project also demonstrated that major upgrades to critical cooling infrastructure can be completed with zero downtime when carefully planned and executed. Lessons learned through delivery are being carried forward to refine future phases and support continuous improvement.
For the data centre operator, this project reinforces confidence in its cooling infrastructure at one of its key Australian sites. For SAGE, it showcases a capability to deliver complex, high-availability control system upgrades in environments where uptime is non-negotiable, setting a strong foundation for future mission-critical projects.
Read the Case Study here