What liquid is used in immersion cooling?

Immersion cooling uses special dielectric liquids to cool high-performance electronics. These liquids are safe, non-conductive, and have excellent heat transfer capabilities.

Immersion cooling liquids are dielectric fluids designed to absorb and transfer heat efficiently without causing short circuits or corrosion in electronic components.

These liquids have become the heart of next-generation thermal management systems, especially for data centers, EV batteries, and power electronics.

What is immersion cooling?

Immersion cooling is a process where electronic components are fully submerged in a thermally conductive but electrically non-conductive liquid. The liquid absorbs heat directly from the components and transfers it to a cooling unit.

Immersion cooling is a technique where devices are immersed in a dielectric liquid to remove heat efficiently, reducing the need for traditional air cooling systems.

Understanding the mechanism

When devices like GPUs or power converters generate heat, the dielectric liquid absorbs it instantly. The liquid then flows to a heat exchanger where the heat is removed, and the cooled liquid returns to the system.

There are two main types:

1. Single-phase immersion cooling – The liquid remains in the same phase and is continuously circulated.
2. Two-phase immersion cooling – The liquid boils and changes phase, absorbing large amounts of heat before condensing back.

Cooling Type	Mechanism	Application
Single-phase	Liquid remains stable and circulates	Data centers, power modules
Two-phase	Liquid evaporates and condenses	High-density servers, GPUs

Immersion cooling eliminates fans and airflow restrictions, making it quieter and more energy-efficient than air or liquid cold plate systems.

What liquid is used in immersion cooling?

The type of liquid used in immersion cooling determines both performance and safety. It must not conduct electricity and should have excellent thermal properties.

Most immersion cooling systems use synthetic dielectric fluids, such as mineral oils, fluorocarbon-based fluids, or engineered hydrocarbon fluids.

Common immersion liquids

1. Mineral oil – Cost-effective and widely available, but heavier and less efficient in long-term use.
   
2. Fluorocarbon fluids (like 3M™ Novec™) – Chemically stable, non-flammable, and low viscosity, ideal for two-phase systems.
   
3. Synthetic hydrocarbons (PAO or esters) – Eco-friendly and customizable thermal properties.
   
4. Silicone oils – Stable at high temperatures and suitable for sensitive electronics.

Type	Conductivity	Stability	Common Use
Mineral oil	Non-conductive	Moderate	Low-cost data centers
Fluorocarbon fluid	Non-conductive	Very high	High-performance servers
Synthetic hydrocarbon	Non-conductive	High	EV battery cooling
Silicone oil	Non-conductive	High	Aerospace systems

Each liquid has different boiling points, viscosity, and environmental effects. Choosing the right one depends on heat load, maintenance requirements, and sustainability goals.

What are the benefits of immersion liquids?

Immersion liquids bring several advantages compared to air or cold plate cooling. They not only enhance heat transfer but also improve reliability and system life.

Immersion liquids reduce energy consumption, protect components from dust and corrosion, and allow higher power density operation with stable temperature control.

Key advantages explained

1. Better thermal performance

Liquids have higher heat capacity and thermal conductivity than air. This means they absorb heat faster and maintain stable operating temperatures.

2. Noise and vibration reduction

Immersion cooling removes the need for fans, reducing mechanical stress and noise pollution.

3. Extended component life

Electronic components under stable thermal conditions age slower. Less heat cycling means fewer failures.

4. Energy savings

By eliminating fans and chillers, immersion systems can reduce energy use by 30%–50%, depending on system design.

5. Environmental protection

Modern dielectric fluids are non-toxic and can be recycled or reused, lowering carbon footprint.

Example: Immersion cooling in data centers

In data centers, immersion cooling allows servers to run at high power density without air conditioning. The liquid directly contacts the heat sources, improving performance and efficiency.

How to choose the best immersion liquid?

Selecting the right liquid is crucial for performance, safety, and cost-efficiency.

The best immersion liquid depends on thermal conductivity, dielectric strength, stability, environmental impact, and system compatibility.

Factors to consider

1. Thermal performance

The liquid should have high heat capacity and low viscosity to ensure smooth circulation and efficient cooling.

2. Dielectric properties

It must not conduct electricity or cause corrosion. Dielectric strength should remain consistent over time.

3. Chemical stability

Long-term stability is important, especially for systems that run ²⁴⁄₇. Some oils may degrade or absorb moisture.

4. Environmental impact

Choose low-GWP (Global Warming Potential) and non-toxic fluids. Some older fluorocarbon fluids have high environmental costs.

5. Cost and availability

While synthetic or engineered fluids offer high performance, their cost can be several times higher than mineral oil.

Comparison of selection criteria

Criteria	Importance	Description
Thermal conductivity	★★★★★	Determines cooling efficiency
Dielectric strength	★★★★★	Prevents electrical faults
Chemical stability	★★★★☆	Impacts long-term use
Environmental safety	★★★★☆	Affects sustainability
Cost efficiency	★★★☆☆	Depends on budget and scale

Selecting a liquid is about balance — matching technical needs with long-term sustainability goals. For large-scale data centers, engineered fluorocarbons may justify higher costs with better reliability and energy savings.

What are the trends in immersion cooling technology?

Immersion cooling continues to evolve as demand for high-performance, sustainable solutions grows across industries.

New immersion cooling trends focus on eco-friendly fluids, advanced materials, integrated sensors, and hybrid cooling architectures.

Emerging trends

1. Eco-friendly dielectric fluids

Manufacturers are developing biodegradable and low-GWP fluids that perform like fluorocarbons but with less environmental impact. Hydrocarbon-based and ester-based fluids are gaining popularity.

2. Modular cooling designs

Future systems are becoming modular and scalable, making installation and maintenance easier for data centers and industrial applications.

3. Integration with AI and IoT

Sensors and AI algorithms monitor temperature, viscosity, and flow rate, predicting maintenance needs and optimizing performance in real time.

4. Hybrid thermal systems

Some manufacturers combine immersion cooling with cold plate or heat pipe systems for localized cooling of hot spots.

5. Adoption in new sectors

Beyond data centers, immersion cooling is entering EV batteries, aerospace systems, and renewable energy inverters where space and temperature control are critical.

Example: Smart immersion cooling system

Recent developments include smart fluids that adjust viscosity with temperature and integrated micro-bubble control for consistent cooling. These innovations help maintain performance while reducing energy consumption.

Conclusion

Immersion cooling liquids are transforming how we manage heat in modern electronics. The right liquid not only ensures stable performance but also drives sustainability and energy efficiency. As technology advances, eco-friendly and intelligent immersion systems will become the new standard.