Lenovo Neptune: Is Warm Water Data Centre Cooling the Future

Lenovo has expanded its Neptune liquid cooling technology across its data centre portfolio as operators confront the escalating thermal and energy demands of modern AI environments. 

The announcement coincides with Lenovo’s position at the top of both the Top500 and Green500 lists, driven by Neptune enabled supercomputers designed for high-density, energy-efficient computing.

Neptune’s design focuses on reducing total facility power use at a time when traditional air cooling is no longer capable of supporting the heat output of dense AI and HPC systems. 

Lenovo reports that servers running on Neptune operate with up to 40% lower power than comparable air cooled systems, providing a route to stable performance without increased cooling overheads.

A cooling model designed for AI scale

Increasing AI workloads have created a step change in heat generation, pushing air based systems close to their practical limits. 

The IDC & Lenovo CIO Playbook 2025 identifies sustainability as a priority for technology leaders, and this includes reducing the energy cost of cooling.

Neptune Direct Water Cooling circulates warm water directly to processors and memory modules to extract heat at source.

Unlike chilled water systems that require coolant at roughly 18°C, Neptune operates with water temperatures up to around 45°C. This eliminates chillers, reduces dependence on air handling equipment and increases efficiency for high-density racks.

The sixth generation of Neptune builds on more than a decade of engineering and hundreds of patents. 

Lenovo has introduced a new vertical liquid-cooled chassis designed to support accelerated computing in a compact footprint. The system is fully liquid-cooled, removing the need for internal fans and lowering energy use across the data hall.

Integrating liquid cooling into Lenovo’s net zero strategy

Neptune forms a core part of Lenovo’s plan to achieve net zero carbon emissions by 2050, validated by the Science Based Targets initiative. 

By reducing cooling requirements and supporting warm water loops that integrate easily into existing facilities, the technology supports long-term emissions reduction and energy efficiency targets.

Demand for such solutions is rising sharply in Asia Pacific, where electricity use linked to AI, cloud and digital services continues to grow. Lenovo forecasts that regional data centre consumption could rise from 320TWh in 2024 to 780TWh in 2030. Against this backdrop, energy efficiency is increasingly tied to commercial viability.

Kumar Mitra, Executive Director for Lenovo Infrastructure Solutions Group in Central Asia Pacific and Australia & New Zealand, says: “Across Asia Pacific, organisations are looking for AI infrastructure that is not only powerful but also fundamentally more energy efficient. Neptune gives our customers that advantage. 

“Our leadership on the Top500 and Green500 rankings demonstrates the real-world impact of these innovations. As AI scales, solutions that combine performance with responsible energy use will define the next era of digital growth, and that is exactly what Lenovo is delivering.”

Performance data and real world deployments

The Neptune ecosystem combines Direct to Node warm water cooling, Rear Door Heat Exchangers and Thermal Transfer Modules in a closed loop architecture.

Warm coolant flows through cold plates mounted on key components and returns around 10-15 °C hotter before transferring heat into a separate facility loop. The process avoids chilled water entirely and stabilises performance even at high rack densities.

Lenovo’s ThinkSystem SR780a, which uses Neptune cooling, has reached a Power Usage Effectiveness of 1.1. PUE measures the ratio of total facility power to IT power and a score of 1.1 indicates that only 0.1 watts are used for cooling per watt of computing. Such levels are rarely achievable with air-cooled systems.

Neptune powered platforms are already in use for some of the world’s most demanding workloads. DreamWorks Animation recorded a 20% performance increase with reduced cooling requirements when adopting Neptune cooled HPC systems. 

The technology is also used by meteorological agencies in Korea and Malaysia, as well as universities, research centres and digital content studios across Asia Pacific.

Neptune systems now support several of the highest ranked supercomputers on the Green500 list, contributing to Lenovo’s leadership in sustainable high performance computing.