What to Consider When Selecting Pressure Sensors for Your Liquid Cooling Systems in Data Centers

Data centers are the central hubs of the digital world, but as artificial intelligence reshapes computing, data centers are running hotter than ever. Traditional air-cooling systems are struggling to keep up with high-density servers, leading to rising energy costs, efficiency losses and costly downtime. To address this challenge, liquid cooling has emerged as a highly effective solution, capable of removing heat far more efficiently and enabling greater computing density beyond what traditional air cooling was built to handle.

Ashcroft, together with its parent company Nagano Keiki Co Ltd., is a leading authority in pressure measurement and sensing technologies designed to keep liquid cooling systems safe, efficient and reliable. With decades of expertise across demanding industries, customers trust Ashcroft’s expertise to guide data center operators on selecting the best pressure and temperature instrumentation to ensure a smooth transition to advanced cooling methods.

Read this article to learn how liquid cooling works, the different system types available, the benefits they deliver over air cooling and key considerations for implementation.

What is liquid cooling and how does it work?

Liquid cooling uses specially designed coolant systems to absorb and transport heat away from critical data center components, offering a more efficient alternative to air cooling. This technology is increasingly important as racks reach power densities that air alone cannot manage. By transferring heat through liquid, which can carry heat away thousands of times more effectively than air, operators can achieve both higher performance and greater energy efficiency.

These systems come in several configurations, each designed for specific applications and performance goals. The two main configurations, direct-to-chip cooling and immersion cooling, each operate as either a single-phase or two-phase system:

• Direct-to-chip setups mount cold plates or heat sinks directly onto CPUs, GPUs or other high-heat components. The plates absorb heat and transfer it into a circulating liquid coolant, which then moves the heat to an external heat exchanger.  This method offers precise, targeted cooling and is ideal for retrofitting high-density zones in existing facilities. 
  
  Amazon Web Services (AWS) has deployed direct-to-chip cooling in racks exceeding 80 kW to maintain stable performance without requiring excessive airflow. Microsoft is another example of companies shifting from traditional air cooling to liquid cooling. 

• Immersion cooling submerges entire servers into a non-conductive dielectric fluid. The fluid absorbs heat directly from all surfaces and transfers it to a heat exchanger. This approach eliminates server fans, reduces noise and significantly cuts power consumption. Plus, it supports extremely high-density deployments, making it a strong choice for AI and high-performance computing (HPC) environments.

DataCenter Magazine also highlights the transition to immersion cooling by other companies and estimates "cooling energy reductions of more than 90%, especially in AI training environments with high thermal output."

In both direct-to-chip and immersion setups, the heated coolant is moved through a closed-loop Coolant Circulation System of pipes and heat exchangers. The heat is then returned to the outside environment or transferred into a secondary cooling loop for reuse, sometimes even for building heating. Closed-loop circulation keeps coolant clean, prevents contamination and maintains consistent system performance.

What challenges come with each type of liquid cooling system?

While liquid cooling offers many advantages, each system type comes with unique challenges that operators must address:

• Direct-to-Chip Cooling: Research published by ASHRAE shows copper cold plates can degrade under stress, leading to corrosion, leakage or blockages that impair coolant flow and reliability. Pressure monitoring sensors can detect subtle pressure changes that indicate early-stage problems before they affect thermal performance for enhanced accuracy and reliability.
  
  
• Immersion Cooling: A ScienceDirect study highlights that single-phase immersion systems require well-designed coolant flow channels to minimize pressure losses and maintain efficiency. Pressure sensors provide visibility into coolant flow performance and can alert operators to fluid degradation, contamination or blockages.
  
  
• Coolant Circulation Systems: ASME research on coolant distribution units (CDUs) shows that pressure differentials across pumps, manifolds, and cold plates can destabilize cooling performance under varying loads. Real-time pressure sensors help identify these anomalies early, enabling proactive maintenance and preventing downtime.

Figure 1: Role of Pressure Sensors in Liquid Cooling Systems

What to look for in a pressure sensor for liquid cooling systems.

Regardless of configuration, pressure sensors play a central role in keeping coolant loops stable, efficient and safe. They are your system’s early warning system to help operators maintain pump pressure, detect leaks or blockages and manage rapid pressure swings caused by temperature changes or phase transitions.

When choosing a pressure sensor for liquid cooling, several key factors should be considered:

• Accuracy and Repeatability: Small pressure shifts can indicate developing problems. A sensor must deliver precise, consistent readings over time without frequent recalibration.
  
  
• Long-Term Stability: Cooling systems run continuously under high-cycle conditions. A sensor should resist drift and maintain accuracy over millions of cycles to minimize downtime.
  
  
• Environmental Durability: Vibration from pumps, temperature fluctuations, and rapid pressure spikes are common. The sensor must withstand these stresses without loss of performance.
  
  
• Compatibility and Integration: The sensor should physically fit the installation, offer the right connection types, and work seamlessly with the facility’s monitoring systems.

By selecting pressure sensors that meet these requirements, operators can ensure their liquid cooling systems operate efficiently, protect valuable IT assets, and maintain uptime in even the most demanding environments.

For example, the Ashcroft® S1 OEM Pressure Transducer is built with accuracy and repeatability in mind. Using advanced Chemical Vapor Deposition (CVD) technology, the S1 bonds polysilicon strain gauges directly to a stainless-steel diaphragm, ensuring consistent, reliable measurements. It also features TruAccuracy™ calibration right out of the box, meaning operators get precise performance without field adjustments. Its compact design makes it well-suited for rack-level monitoring, where space is limited but accuracy is critical.

The Ashcroft® G2 Pressure Transducer is designed for long-term stability and environmental durability. Its rugged, field-proven thin film polysilicon sensing element offers outstanding resistance to shock, vibration, and overpressure, making it ideal for facility-level installations and high-vibration areas near pumps or distribution units. The G2 delivers reliable, repeatable data under harsh conditions, ensuring coolant performance remains stable over millions of cycles.

In practice, operators can use the S1 at the rack level near cold plates and the G2 at the facility level near pumps and manifolds, creating complete visibility into coolant loop performance from end to end.

Figure 2: Ashcroft® Liquid Cooling Pressure Sensors Highlights

Ready to learn more?

The right instruments make all the difference in liquid cooling systems. With accurate, reliable pressure sensors, you can prevent costly downtime, protect your IT investments and keep your data center running at peak performance.

To learn more, check out some of our other related articles:

• Differential Pressure Sensors for Data Centers
• What is CVD Technology?
• How to Measure Very Low-Pressure in Controlled Environments
• What are the Advantages of Ashcroft Pressure Sensors?

If you have questions, contact us to speak to a product expert. In the meantime,  download our guide to learn more about mistakes you can make when selecting a pressure sensor.