NEXTDC Reaches Unprecedented Sustainability Goals Through Innovative Cooling Technology

Data centers require continuous cooling operations to protect servers that generate significant heat on a 24/7 basis. Unlike traditional commercial buildings where cooling systems may operate only half the year, data center infrastructure demands high run hours. Consequently, energy consumption in these facilities is substantial, and any efficiency optimization yields large annual power savings.

To improve efficiency, modern data centers have increased operating temperatures within server rooms. While this practice reduces overall power consumption, it shifts the operating parameters for cooling equipment. Higher chilled water temperatures combined with low ambient external conditions force compressors to operate at low compression ratios, a condition known as low lift. Standard compressors are not traditionally designed to run reliably or efficiently within these specific operating parameters.

Collaborative Engineering for Low-Lift Operation
To address these requirements, the facility operator NEXTDC collaborated with Smardt Chiller Group and Danfoss. The engineering teams developed a technical solution to expand the operating map of oil-free centrifugal compressors. This mechanical and software modification allows the units to function reliably under high chilled water temperatures and low ambient conditions.

The resulting technical configuration, known as SmardtLift, implements specific software changes and physical improvements to enable the Danfoss Turbocor oil-free centrifugal compressors to operate stably at low lift. Smardt developed specialized software to optimize chiller performance precisely during these periods of low compression.

Technical Advantages of Oil-Free Compressors
The operator selected this solution based on the specific performance characteristics of oil-free magnetic bearing technology. Traditional oil-based chillers suffer from a 10% to 30% loss in capacity and efficiency over their operational lifespan. This degradation occurs because oil coats the internal surfaces of the heat exchangers, acting as an insulator and inhibiting heat transfer. Oil-free compressors eliminate this degradation, maintaining consistent performance over time.

For critical data center infrastructure, system availability is vital. The chosen configuration utilizes multiple compressors per chiller rather than a single large compressor, providing built-in redundancy to support the facility's 100% uptime guarantee. Furthermore, the absence of a conventional oil management system removes thermal lag during startup. This mechanical design enables a fast-restart capability of 30 seconds, providing rapid restoration of cooling capacity after power interruptions.

System Deployment and Integration
The technical solution was initially deployed as a pilot project on one of the existing Smardt chillers at the 15MW M1 hyperscale facility in Melbourne. Danfoss supported the deployment by supplying complementary components for the complete hydronic system, including large heat exchangers and variable speed drives. This integration ensured that the control logic of the compressor matched the hydraulic flow dynamics of the entire cooling loop. Following the validation of the pilot project, the operator initiated plans to implement the low-lift chiller configuration across its broader fleet of data centers.

Quantifiable Energy Savings and Performance Results
Data collected during the pilot phase confirmed that the low-lift configuration optimized chiller efficiency when ambient external temperatures aligned with the specific cooling threshold of the facility. The operational integration of the modified software and oil-free compressors reduced the energy costs of the chillers by just over 30%, depending on fluctuating ambient conditions.

Edited by Evgeny Churilov, Induportals Media - Adapted by AI.

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