What liquid is used for immersion cooling?

When computers and data centers run nonstop, they generate massive heat. Air cooling struggles to keep up, and fans become noisy and inefficient. That is why many engineers are turning to immersion cooling.

Immersion cooling uses dielectric liquids—fluids that do not conduct electricity—to directly submerge and cool electronic components safely and efficiently.

It sounds futuristic, but immersion cooling is already common in high-performance computing and crypto mining. Let’s explore how it works, what fluids are used, and how the technology is evolving.

What is immersion cooling technology?

Air can only carry away so much heat. Once systems hit certain power levels, airflow alone cannot maintain stable temperatures. Immersion cooling solves this by removing the air entirely.

Immersion cooling technology involves submerging heat-generating components—like CPUs, GPUs, or servers—into a thermally conductive but electrically non-conductive liquid that absorbs and transfers heat efficiently.

There are two main types of immersion cooling: single-phase and two-phase. Both use special fluids, but they behave differently.

Types of immersion cooling

Type	Process	Example Use
Single-phase	Liquid stays in liquid form; pumped through heat exchangers	Data centers, crypto farms
Two-phase	Liquid boils and condenses, removing heat through vaporization	High-performance computing, supercomputers

In single-phase systems, components sit in a bath of dielectric oil. The liquid absorbs heat, then circulates through a heat exchanger to release it before returning to the tank. The fluid never changes state.

In two-phase systems, the fluid boils at a low temperature—often between 50°C and 60°C. The vapor rises, hits a condenser, cools down, and drips back into the bath. This cycle offers extremely consistent cooling.

The main advantage is uniform temperature across components. No fans, no hotspots, and no dust buildup. The system becomes both quieter and more efficient.

What are the benefits of immersion liquids?

Using immersion liquids instead of air changes the whole thermal game. Air has low heat capacity and conductivity; immersion fluids are hundreds of times better at moving heat.

Immersion cooling liquids provide superior heat transfer, eliminate fan noise, reduce dust and corrosion, and improve energy efficiency in high-density systems.

Main benefits explained

Benefit	Description	Impact
High heat transfer	Fluids conduct and store heat efficiently	Keeps CPUs and GPUs stable under load
Silent operation	No need for air fans	Ideal for data centers or quiet labs
Dust-free environment	Enclosed system keeps dust out	Lower maintenance
Component longevity	Stable thermal environment	Less wear on hardware
Energy savings	Reduced air conditioning demand	Lower PUE (Power Usage Effectiveness)

Why immersion liquids matter

I once visited a data facility where hundreds of servers ran in oil-filled tanks. The room was almost silent, and no cold air was blowing. Yet, each system maintained perfect temperatures. That’s the power of immersion liquids—they handle more heat with less effort.

In numbers, the thermal conductivity of these fluids can be 1,000 times higher than air. This means faster heat removal, less thermal stress, and smoother performance across all nodes.

Environment and reliability

Because the liquid eliminates direct contact with air, oxidation and dust are nearly zero. Connectors last longer, and corrosion is almost nonexistent. Systems can even run in warmer climates without heavy HVAC systems, cutting total energy costs by up to 40%.

How to choose the right immersion fluid?

Not every liquid is safe for electronics. Using the wrong one—like water or standard oil—can cause short circuits or degradation. The choice of immersion fluid depends on chemistry, cooling type, cost, and long-term stability.

To choose the right immersion cooling fluid, evaluate thermal performance, electrical insulation, viscosity, material compatibility, and environmental safety.

Key selection factors

Property	Description	Why It Matters
Dielectric strength	Ability to resist electric current	Ensures safety for electronics
Thermal conductivity	How efficiently it transfers heat	Directly affects cooling efficiency
Viscosity	Resistance to flow	Affects pump performance
Material compatibility	Interaction with plastics, seals, and PCB coatings	Prevents corrosion or swelling
Environmental impact	Biodegradability, toxicity	Determines disposal and handling methods

Types of immersion liquids

1. Mineral oil

   • Widely used in single-phase systems.
     
   • Inexpensive and non-conductive.
     
   • May oxidize over time and needs filtration.

2. Synthetic hydrocarbons (PAO-based fluids)

   • Higher stability and lower viscosity than mineral oil.
     
   • Better thermal performance and longer life.
     
   • Common in industrial and HPC systems.

3. Fluorocarbon-based fluids (e.g., 3M Novec, Chemours Opteon)

   • Used in two-phase systems.
     
   • Non-flammable, clean, and low viscosity.
     
   • More expensive but efficient for precision applications.

4. Silicone oils

   • Stable over a wide temperature range.
     
   • Chemically inert and compatible with many materials.
     
   • Suitable for prototypes or sensitive components.

Practical selection advice

If you are building a custom or experimental setup, synthetic hydrocarbons are often the best balance between cost and performance. For industrial-grade systems or high-end computing, fluorocarbon fluids are preferred because of their predictable boiling points and clean operation.

Before choosing, always confirm the fluid’s compatibility with seals, cables, and plastics. Some fluids can slowly damage insulation or adhesives over time.

What are the advances in immersion cooling?

Immersion cooling is no longer a niche concept. It is becoming central to modern computing, especially with the rise of AI, cloud services, and 5G infrastructure. The latest innovations make it smarter, cleaner, and more sustainable.

Recent advances in immersion cooling include next-generation eco-friendly fluids, modular tank systems, integrated heat recovery, and AI-based thermal management.

1. Eco-friendly immersion fluids

Earlier generations of fluorocarbon fluids had high global warming potential (GWP). New fluids are engineered with low-GWP formulations and improved biodegradability. These include the new Opteon SF and 3M Novec replacements, which are non-flammable, stable, and environmentally safer.

2. Modular immersion systems

Manufacturers are designing modular tank systems that can hold one or several server boards per unit. These tanks can be connected like building blocks, allowing data centers to scale immersion capacity easily.

3. Heat reuse and recovery

Instead of wasting heat, new immersion systems can capture and reuse waste heat. Some facilities use it to warm nearby buildings or feed into heat recovery loops, improving total energy efficiency.

4. AI-based cooling optimization

AI now monitors fluid temperature, flow rates, and thermal loads in real time. It predicts when components will heat up and adjusts flow or condenser speed automatically. This keeps temperatures stable while saving power.

5. Material and component adaptation

Server manufacturers are designing immersion-ready hardware—PCBs, connectors, and coatings that resist swelling or delamination in dielectric fluids. This integration reduces the risks that early systems faced.

Emerging research areas

Innovation	Description	Impact
Bio-based dielectric fluids	Derived from renewable oils	Lower carbon footprint
Microchannel heat exchangers	Compact and efficient	Improved fluid circulation
Smart monitoring sensors	Embedded thermal and fluid sensors	Predictive maintenance
Vapor control membranes	Prevent fluid loss	Longer system life

Real-world adoption

Big data players and AI research centers are already deploying immersion cooling for GPU clusters. For example, modern supercomputers can reduce their cooling energy by over 90% using immersion systems compared to traditional HVAC.

At smaller scales, some PC enthusiasts have built transparent oil tanks that look like aquariums. These serve as both functional and aesthetic demonstrations of the technology’s potential.

The future outlook

The next decade will likely bring standardization of immersion-ready components, cheaper low-GWP fluids, and hybrid systems that combine immersion cooling with liquid loops for selective parts. With the growing demand for high-density computing, immersion will shift from experimental to essential.

Conclusion

Immersion cooling replaces air with a special dielectric liquid that safely absorbs and removes heat from electronics. These fluids—whether mineral oil, synthetic hydrocarbons, or fluorocarbons—enable quiet, efficient, and reliable thermal management. With new eco-friendly formulas and smarter system control, immersion cooling is shaping the future of sustainable computing.