Immersion Cooling for Data Centers,

How It Works & Why It Matters

How Does Immersion Cooling Work?

Immersion cooling system basically consists in completely submerging a server into a dielectric liquid. This type of liquid does not conduct electricity; therefore, it is totally safe for the electronics components to be submerged od the urgency and works every daywithout any risk of shortcuts and oxidation.

This way, all waste heat generated by the components is captured by the dielectric liquid inside the tank, which is capable of absorbing around 1500 times more heat than air, for the same volume. The heat then flows to a heat exchanger where it’s cooled by a secondary air to liquid or liquid to liquid heat exchanger to be dissipated or reused

Why Choosing Immersion Cooling?

A data center is a facility housing thousands of servers, computers, and network devices, all of which generate significant amounts of heat, commonly referred to as "waste heat". This heat is a byproduct of the Joule effect: virtually all the electrical energy consumed by IT components is ultimately released as heat.


It is well established that excess heat degrades both the performance and the lifespan of IT equipment. To address this, data centers must be continuously cooled to maintain stable operating temperatures. Traditionally, this is achieved using energy-hungry systems such as fans and air conditioning units, which carry a significant environmental cost over time.


Today, environmental concerns are at the heart of every industry conversation. Conventional cooling methods are no longer sufficient. What can we do? Switching servers off is simply not an option.


AI Is Reshaping Data Center Energy Demands: Key Figures


The global data center market was valued at approximately $348 billion in 2024 and is projected to exceed $1 trillion by 2034, growing at an 11.2% CAGR (GlobeNewswire / McKinsey). Global capacity is expected to double from 103 GW in 2025 to 200 GW by 2030, driven by the explosive growth of AI and cloud computing (JLL, 2026), and with it, an unprecedented infrastructure investment supercycle of up to $3 trillion by 2030.

This rapid expansion comes at a significant environmental cost. Global electricity demand from data centers surged by 17% in 2025, with AI-focused facilities growing even faster at +50% (IEA, 2025). Consumption is projected to nearly double from 485 TWh in 2025 to 950 TWh by 2030, representing approximately 3% of global electricity demand (IEA, Energy and AI Report, 2025). The carbon footprint of AI systems alone could reach between 32.6 and 79.7 million tonnes of CO₂ in 2025, while water consumption could reach up to 764 billion litres (ScienceDirect, 2025).

These figures make one thing clear: conventional cooling methods are no longer sufficient. Reducing the energy and environmental footprint of data centers is no longer optional, it is a strategic and operational imperative.

2CRSi recognized this urgency and works every day to develop new cooling methods to cool IT equipment in all type of settings, such as direct on chip cooling or immersion cooling.

What Is the Difference Between Single-phase and Two-phase Immersion Cooling?

The terms "single-phase" and "two-phase" refer to the behavior of the dielectric coolant as the servers heat it.

Single-phase immersion cooling

With  single-phase immersion cooling , servers are totally submerged vertically in a coolant bath filled with a hydrocarbon-based dielectric liquid. The heat produced is then transferred to the coolant through direct contact with the components. It is then sent to a cooling tower through a  cooling distribution unit  (CDU) to be cooled and sent back in the tank.

Single-phase immersion cooling is straightforward, cost-effective, easy to manage, and requires minimal maintenance.

Here a summarization of single-phase liquid cooling advantages versus air-cooling:

  • Quiet operation
  • Lower CAPEX and OPEX (per kW)
  • Better TCO (per kW)
  • About 10x more heat rejection capacity
  • Less space required
  • More energy efficiency and sustainability

Single phase immersion cooling system diagram

How Single phase immersion cooling works

Two-phase immersion cooling

With  two-phase immersion cooling , the servers are sealed into a tank filled with a fluorocarbon-based liquid. This liquid has a low boiling point and the heat generated by the components makes it boil rather easily. The boiling liquid is the core of the two-phase system, as the heat turns the liquid into gas, causing a phase change.

The gas goes through a water-cooled condenser coil, placed into the top of the sealed racks. Inside, the vapor is transformed back into liquid which drips back into the tank to be recycled through the system.

Two-phase system has two downsides: the fluorocarbon-based liquid is expensive and must be handled with care.

Here is a summary of two-phase liquid cooling solution:

  • Quiet operation
  • Faster builds than air cooling
  • Less space requirement (compared to single-phase)
  • Lower CAPEX and OPEX (per kW)
  • Better TCO (per kW)
  • Best efficiency in any form of cooling
  • Around 2x more heat rejection capacity (compared to single-phase)
  • Waste heat can be reuse

Two phase immersion cooling system diagram

How two phase immersion cooling system works

Immersion-cooled GPU and AI servers

Immersion cooling isn't just for general-purpose compute, it has become the cooling solution of choice for the most dense and demanding GPU infrastructures. At 2CRSi, we design and manufacture high-performance GPU servers specifically engineered for immersion cooling for data centers, both single-phase and two-phase.


Our immersion-cooled GPU servers take full advantage of the technology's benefits: optimal heat dissipation, reduced energy consumption, and a PUE close to 1. From AI training to large-scale inference, our immersion-cooled GPU servers are the ideal infrastructure for high-density, energy-efficient data centers.


Our immers​​​​ion cooling servers


How effective is liquid immersion cooling?

Compared to traditional air cooling, liquid immersion cooling dramatically reduces the total cost of ownership (TCO), meaning the combined cost of acquisition and operation over the system's entire lifespan.


  • Improves IT hardware’s lifespan by 20%, reducing replacing costs,
  • 30% of TCO saving,
  • 39% reduction of carbon emissions,
  • 91% reduction of water consumption,
  • Reduction of noise pollution.

Thanks to the dielectric fluid, immersion cooling ensures a much more uniform temperature distribution across components compared to other cooling methods. As a result, components are no longer subjected to the thermal stress caused by sudden temperature fluctuations.

Working in a conventional air-cooled data center can be physically demanding. Ambient noise can reach up to 90 decibels, leading to poor and dangerous working conditions. With an immersion cooling system, fans are out of the equation, therefore noise pollution is avoided.

Using liquid immersion cooling in a data center also results in a reduction of carbon emissions up to 39% and of water consumption up to 91%, according to our own research.

Power Usage Effectiveness (PUE) with Immersion Cooling

One of the most critical metrics for data center operators is PUE, which is the ratio of total facility energy consumption to the energy actually used by IT equipment.


A perfect PUE score is 1.0, meaning 100% of energy goes directly to computing. The global average for air-cooled data centers sits around 1.5 to 1.6, meaning up to 60% of energy is wasted on cooling and infrastructure overhead. Immersion cooling consistently achieves PUE scores as low as 1.02 to 1.05, making it one of the most energy-efficient cooling technologies available today.


Immersion cooling: for which applications?

One of immersion cooling's greatest strengths is the sheer breadth of industries it serves. Any sector that demands high-performance computing and low latency can benefit from immersion-cooled infrastructure.

  • AI and LLM training: training large language models and frontier AI systems requires sustained, extreme compute density over long periods.
  • Cloud computing and hyperscale data centers: high-density cloud infrastructure demands maximum compute per rack.
  • Cloud gaming: real-time rendering and ultra-low latency requirements make thermal management critical.
  • Healthcare and medical imaging: AI-powered diagnostics, genomics pipelines, and medical imaging analysis generate intense compute bursts that benefit from stable, efficient cooling.
  • IoT and edge computing: compact, energy-efficient immersion cooling systems can be deployed in non-traditional environments, bringing high-density compute closer to the data source.
  • Video surveillance and security: large-scale video analytics powered by AI require continuous, reliable processing.

Air Cooling vs Immersion Cooling

Comparison of the water consumption of two data centers

A measure system called WUE (Water Use Efficiency) was created to measure water and energy consumption in data centers. This metric is calculated by dividing data center annual energy source and site water usages (in Liters) by total IT power consumption.

 

 

Data Center A

Air cooling

Data Center B

Immersion cooling

Electricity

 

Total IT Power Consumption

4.2 MW

3.36 MW


Total Facility Power

5.7 MW

3.5 MW

Water

Daily site water usage

507 300 L

43 750 L


Energy source water per year

94.07 million L

57 million L


Site Water Usage per year

185.16 million L

15.97 million L

WUE

Site WUE

7.59 L/kWh

2.48 L/kWh

 

Comparison of the carbon footprint of two data centers

Carbon emissions come mainly from the extraction of raw materials and their transformation into electronic components, as well as the electrical production of electricity. As we know, the carbon footprint of each country differs.

In France, 1kWh of electricity is equal to 0.014 kg of CO2. Thanks to nuclear plants, France’s carbon footprint is lesser than the USA, which reaches 0.454 kg of CO2 for 1 kWh of electricity.

Carbon Usage Effectiveness (CUE) is a metric that calculates and determines the amount of carbon gas emitted by a data center daily. It was developed by the Green Grid and adopted around the world. It is calculated by dividing the total CO2 emissions equivalents of the facility’s energy consumption by the total IT energy consumption.

 


 

Data Center A

Air cooling

Data Center B

Immersion cooling

  Electricity 

Capacity

12 000 servers

12 000 servers

Average Power Consumption (per server)

350 W

280 W*


Total IT Power Consumption

4.2 MW

3.36 MW


Cooling Overhead

30%

2%


Electrical Overhead

6%

1%

Effective PUE (Power Usage Effectiveness)
1.36 1.03


Total Facility Power

5.7 MW

3.5 MW


Energy Consumption per year

50 million kWh

30.3 million kWh

  CO2

USA Carbon emissions per year

22.7 million kgCO2

13.8 million kgCO2


FRANCE Carbon emissions per year

5.2 million kgCO2

3.2 million kgCO2

CUE

USA Effective CUE

0.62 kg CO2/kWh

0.47 kg CO2/kWh


FRANCE Effective CUE

0.14 kg CO2/kWh

0.12 kg CO2/kWh

*reduce due to fans removal