GMORS

Every time we stream a video, save photos to the cloud, shop online, or send a message, data centers are working behind the scenes. These facilities house thousands of servers that process and store the digital information used by individuals and businesses around the world.

All of these servers generate heat as they operate. Traditionally, data centers have relied on air cooling systems to remove this heat and keep equipment running safely.

However, as these digital services continue to grow, data centers must handle increasing amounts of computing power. This trend has accelerated even further with the rise of AI applications and large language models, which require significantly more processing capacity than many traditional workloads.

To deliver this performance, servers are equipped with more powerful processors. These chips consume large amounts of electricity, and much of that energy is released as heat during operations.

In addition, data center operators often install more computing power within the same server rack to make better use of available space. As a result, more heat is generated in a smaller area, making it increasingly difficult for air cooling alone to remove the heat effectively.

This is why liquid cooling in data centers is becoming an increasingly important solution. But what is liquid cooling in data centers, and how does it work? Let’s start with the basics.

What Is Liquid Cooling in Data Centers?

Liquid cooling in data centers is a method of removing heat from servers by using a circulating liquid instead of relying only on air.

As the liquid flows through the cooling system, it absorbs heat from the servers and carries that heat away. The warmed liquid is then cooled and recirculated to repeat the process.

Compared with air, liquid can carry away much more heat. This allows data centers to use faster, higher-performance processors and to install more servers within the same rack.

In other words, liquid cooling helps data centers support greater computing power in the same physical space.

For this reason, liquid cooling is becoming increasingly common in environments with intensive computing demands, including hyperscale data centers, AI training clusters, high-performance computing (HPC) facilities, and edge computing environments.

In the next section, we’ll look at how liquid cooling works in data centers and the main cooling architectures used today.

How Does Liquid Cooling Work in Data Centers?

Liquid cooling systems used in data centers can be broadly divided into two main approaches: Direct Liquid Cooling (DLC) and Immersion Cooling. Both methods remove heat more efficiently than air cooling, but they differ in how the coolant interacts with the server equipment.

・Direct Liquid Cooling (DLC)

In Direct Liquid Cooling, coolant is pumped through tubes to cold plates attached directly to high-heat components such as CPUs, GPUs, and AI accelerators. Each cold plate contains internal channels, through which the coolant flow. As the coolant passes through these channels, it absorbs heat from the processor. The warmed coolant is then carried to a heat exchanger, where the heat is removed before the coolant is recirculated back through the system.

Direct Liquid Cooling can be divided into two types:

Single-Phase DLC

In single-phase DLC, the coolant remains in liquid form throughout the entire cooling cycle. It absorbs heat from the cold plates, flows to a heat exchanger, and is then cooled and recirculated.

Two-Phase DLC

In two-phase DLC, the coolant partially evaporates as it absorbs heat from the processor. The vapor is then condensed back into liquid and returned to the system. This phase change allows large amounts of heat to be removed very efficiently.

・Immersion Cooling

In Immersion Cooling, the entire server is placed in a tank filled with a special dielectric fluid. A dielectric fluid is electrically non-conductive, which means it can come into direct contact with electronic components without causing short circuits. As the fluid surrounds the server, it absorbs heat from all components rather than only selected chips.

Immersion cooling can also be divided into two types:

Single-Phase Immersion

In single-phase immersion cooling, the dielectric fluid remains in liquid form. The warmed fluid is circulated through a heat exchanger, cooled, and then returned to the immersion tank.

Two-Phase Immersion

In two-phase immersion cooling, the dielectric fluid is formulated to boil at a relatively low temperature. When it absorbs heat from the server components, part of the liquid turns into vapor. The vapor rises to a condenser, where it is cooled and converted back into liquid. The liquid then returns to the tank, creating a continuous cooling cycle.

Why Sealing Matters for Liquid Cooling in Data Centers

Liquid cooling improves heat removal by bringing coolant much closer to sensitive electronic components. While this significantly increases cooling efficiency, it also means that any leakage can pose a direct risk to expensive IT equipment.

Even a small leak can lead to hardware damage, system downtime, coolant contamination, and costly maintenance.

To prevent this, seals are installed throughout the cooling system, including at cold plates, quick disconnect couplings, manifolds, pumps, heat exchangers, and immersion tanks. These seals must keep the coolant securely contained under continuous operating conditions.

Over time, sealing materials are exposed to several challenges:

• Chemical exposure from water-glycol mixtures, refrigerants or dielectric fluids
• Temperature changes that cause materials to harden, shrink, or lose elasticity
• Pressure Fluctuations that place repeated stress on sealing surfaces
• Compression set, where the seal gradually loses its ability to maintain contact pressure
• Contamination control, since seal materials might release substances that could affect coolant performance

Because of these demands, both seal design and material selection play a critical role in the long-term reliability of liquid cooling systems.

In the next section, we will examine the main sealing locations in Direct Liquid Cooling and Immersion Cooling Systems and the sealing solutions used at each point.

 ▍Further Reading: O-Ring Guide: 9 Professional Tips for Choosing the Right Sealing Solution

How Different Sealing Solutions Support Liquid Cooling Systems

Different parts of a liquid cooling system perform different functions, and each sealing location faces its own combination of chemical, thermal, and mechanical challenges. To ensure long-term reliability, sealing materials must be matched to the specific conditions at each point in the system.

Sealing for Direct Liquid Cooling (DLC) Systems

In typical Direct Liquid Cooling (DLC) system, coolant flows from the Cooling Distribution Unit (CDU) through manifolds and flexible hoses to cold plates mounted on processors. Quick disconnect couplings allow individual servers to be connected or removed without draining the entire loop.

Cold Plate Seals

Cold plates are mounted directly on processors such as CPUs and GPUs. Inside the cold plate, coolant flows through narrow channels that absorb heat from the chip.

The seals used in cold plates must be compatible with water-glycol coolants such as propylene glycol and water (PG25). They should also have low extractables to minimize the risk of releasing contaminants that could clog the microchannels.

GMORS offers specially formulated EPDM compounds optimized for water-based cooling systems. These materials combine excellent chemical resistance with low extraction characteristics to help protect coolant purity.

Quick Disconnect Coupling Seals

Quick disconnect couplings allow servers or cooling modules to be connected and removed without draining the entire loop.

Once installed, the seals remain under compression for long periods and must continue to provide reliable sealing performance, even after repeated connection cycles and prolonged exposure to elevated temperatures.

GMORS uses sealing materials that retain their elasticity over time, helping quick disconnect couplings maintain consistent sealing force and dependable leak protection.

Manifold Seals

Manifolds distribute coolant from the main supply line to multiple cold plates or servers. Because they contain many connection points, a leak at any single seal can affect the performance of the entire cooling loop.

The seals in manifolds remain compressed throughout operation and must maintain sealing force despite ongoing temperature changes and pressure fluctuations.

GMORS uses resilient rubber compounds that preserve their shape and sealing force under long-term compression, helping manifold seals deliver dependable long-term performance.

CDU Seals (Cooling Distribution Unit)

The Cooling Distribution Unit (CDU) contains pumps, valves, and heat exchangers that regulate coolant flow, pressure, and temperature.

Seals used in these components must provide reliable chemical resistance and dimensional stability under continuous operation.

GMORS provides precision O-rings and custom seals manufactured to tight tolerances to support dependable sealing in critical CDU components.

Sealing for Immersion Cooling Systems

In an immersion cooling system, servers are placed inside the sealed tanks filled with dielectric fluid. Additional seals are used around tank lids, cable feedthroughs, pumps, and heat exchangers to contain the fluid and, in some systems, its vapor.

Tank Lid Gaskets

Immersion tanks are filled with dielectric fluid and sealed with large gaskets around the lid.

These gaskets must remain compatible with the fluid and maintain a reliable seal across a large surface area.

GMORS offers custom gasket materials designed for long-term exposure to dielectric fluids.

Cable Feedthrough Seals

Power and communication cables must pass through the tank wall without allowing fluid to leak.

These seals must conform closely around each cable while accommodating thermal expansion and movement.

GMORS develops custom-molded sealing solutions for complex cable feedthrough geometries.

Fluid Containment and Vapor Control Seals

In two-phase immersion systems, the dielectric fluid is designed to boil at relatively low temperatures. As the fluid repeatedly evaporates and condenses, the sealing system must contain both liquid and vapor while minimizing fluid permeation.

This phase-change process can also create pressure pulses within the system. Over time, these pressure fluctuations may cause seals to expand and contract repeatedly, increasing the risk of fatigue and leakage.

GMORS provides chemical-inert sealing compounds with low permeability, high tensile strength, and excellent mechanical durability. These materials help reduce fluid loss, maintain stable system pressure, and withstand the repeated pressure fluctuations associated with two-phase cooling.

Pump and Heat Exchanger Seals

Pumps and heat exchangers circulate and cool the dielectric fluid.

Their seals must remain stable during prolonged exposure to specialized cooling fluids.

GMORS offers silicone-free elastomer compounds that help preserve fluid cleanliness and reduce contamination risks in sensitive electronic environments.

Why Choose GMORS Sealing Solutions for Liquid Cooling?

Liquid cooling systems rely on numerous seals to keep coolant securely contained throughout the system. To ensure long-term reliability, these sealing materials must continuously remain stable when exposed to water-glycol coolants, refrigerants, and dielectric fluids. 

GMORS specializes in high-performance sealing solutions for liquid-cooled data centers and high-performance computing (HPC) systems. Our materials and manufacturing processes are designed to support a wide range of cooling architectures, including single-phase and two-phase Direct Liquid Cooling (DLC) and Immersion Cooling systems.

GMORS develops sealing solutions aligned with the liquid cooling standards and design guidelines of the Open Compute Project (OCP). With expertise in material formulation and precision manufacturing, we help customers achieve reliable, long-term sealing performance for next-generation AI and GPU infrastructure.

Contact us to discuss sealing solutions for your liquid cooling applications.

 ▍Further Reading: 5 Core Principles for Choosing O-Ring Materials: A Must-Know Selection Guide