Single-Phase Immersion Cooling Systems for AI & HPC Infrastructure
Immersion cooling has established itself as the most efficient cooling solution for industries running high-compute servers generating significant amounts of waste heat.
Two distinct systems exist: single-phase immersion cooling and two-phase immersion cooling. This page focuses on single-phase liquid immersion cooling, its working principle, key benefits, and the infrastructure it's best suited for.
How Does Single-Phase Liquid Immersion Cooling Work?
Single-phase liquid immersion cooling works by fully submerging servers into a tank filled with a dielectric liquid, which is a non-conductive fluid that is completely safe for electronic components, eliminating any risk of short circuits or oxidation.
Two types of dielectric fluid can be used in single-phase systems: hydrocarbon-based liquids (similar to mineral oil) and synthetic oils. Unlike two-phase immersion cooling, which uses a fluorocarbon-based liquid that boils and undergoes a phase change, the coolant in a single-phase system remains in liquid state throughout the entire cooling process.
Waste heat is transferred directly from the components to the coolant. The heated fluid is then pumped to a heat exchanger, where the heat is transferred to a secondary water circuit before the cooled fluid is sent back into the immersion tank.
Since dielectric coolant is a far better heat conductor than air, single-phase immersion cooling is particularly well-suited for high-density rack environments, and is more cost-effective than two-phase alternatives.
Why Use Single-Phase Immersion Cooling?
Single-phase immersion cooling delivers significant advantages over traditional air-cooled systems, both in terms of performance and total cost of ownership.
By eliminating fans and conventional air cooling infrastructure, it reduces energy consumption, lowers operational costs, and creates a safer, quieter working environment. The dielectric fluid used is non-toxic and non-flammable, acting as a natural fire suppressant and making it inherently safer for data center environments.
Increase power rack density
By reducing the heat generated per component, single-phase immersion cooling allows server components to be packed more closely together.
This enables high-density rack designs that would be impossible with air cooling, maximising compute power per square metre of data center floor space.
Reduce energy usage
Single-phase immersion cooling significantly reduces a data center's energy footprint by eliminating or greatly reducing the need for air cooling units.
Studies estimate that single-phase liquid cooling can consume up to 50% less energy than traditional air-cooled systems, directly translating into lower electricity bills and a reduced carbon footprint.
Extended component lifespan
Components last longer in an immersion cooling environment thanks to the elimination of temperature fluctuations and the removal of fans, which can cause damaging vibrations over time.
This directly reduces hardware replacement costs and improves infrastructure ROI.
Low maintenance
Single-phase immersion cooling requires no CRACs, CRAHs, or chillers. The complex and costly infrastructure typical of air-cooled data centers.
The result is a more reliable setup that demands less maintenance.
Reduce PUE
Single-phase immersion cooling achieves a PUE as low as 1.03, compared to approximately 1.6 for a typical air-cooled data center.
This means that virtually all energy consumed goes directly to powering IT equipment, rather than being wasted on cooling infrastructure.
Reduce TCO
By eliminating fans and conventional air cooling infrastructure, single-phase immersion cooling lowers the total cost of ownership, covering both CAPEX and OPEX over the system's entire lifespan.
Single-Phase Immersion Cooling: for Which Applications?
AI & HPC
High-performance computing and AI workloads are today the primary drivers of demand for single-phase immersion cooling.
Training LLMs, running deep learning pipelines, and operating GPU clusters 24/7 generates extreme and sustained thermal output that conventional air cooling cannot handle efficiently.
Single-phase liquid immersion cooling is the ideal solution for AI infrastructure operators looking to maximise compute density, reduce energy costs, and maintain stable thermal conditions across GPU-intensive workloads, all while keeping PUE as low as 1.03.
Financial Services
The financial industry runs some of the most compute-intensive workloads in existence, high-frequency trading algorithms, real-time risk analysis, fraud detection systems, and Monte Carlo simulations all require sustained, ultra-low latency processing power. Even the slightest thermal throttling can impact performance at a critical moment.
Single-phase immersion cooling eliminates this risk by maintaining stable, homogeneous temperatures across all components at all times, ensuring consistent, reliable performance.
Healthcare & Life Sciences
Healthcare and life sciences are undergoing a profound digital transformation, driven by AI-powered diagnostics, genomics sequencing, drug discovery pipelines, and large-scale medical imaging analysis.
Single-phase immersion cooling supports these requirements with thermal stability, extended component lifespan, and a reduced risk of hardware failure.
Its non-toxic, non-flammable dielectric fluid also makes it inherently safer for sensitive environments.
Media & Entertainment
The media and entertainment industry is now revolving around 4K and 8K content production, real-time visual effects rendering, live streaming at scale, and AI-powered content generation.
These workloads are GPU-intensive, generating thermal output over long, uninterrupted production cycles.
Single-phase immersion cooling is suited to handle this sustained thermal load, maintaining stable temperatures across GPU clusters even under continuous heavy workloads, eliminating the thermal throttling that can slow down render times or disrupt live production pipelines.
2CRSi's Immersion Servers
We design and manufacture servers specifically engineered for single-phase immersion cooling environments. Our immersion-ready range covers both 19" and 21" form factors, offering flexible configurations. Every system is built and tested in our French facilities, with full control over component quality and supply chain.
21" Immersion Ready Systems
Built for high-density immersion tank deployments.
19” Immersion Ready Servers
Compatible with standard immersion cooling infrastructure.