Precision Pressure Monitor for Cooling Water Flow Path Measurement｜Pressure Loss Measurement That Helps Improve Data Center PUE

Precision Pressure Monitor for Cooling Water Flow Path Measurement

Water cooling systems in data centers are critical infrastructure that keep equipment running stably by removing the heat generated by large numbers of servers and network devices through cooling water circuits. A cooling water circuit consists of heat exchangers, piping, pumps that circulate the coolant, and other components, and its flow path must be designed to suit the scale of the data center and the equipment layout.

The MT300 differential pressure model, a liquid-compatible differential pressure instrument, measures the pressure losses occurring at each section of these cooling water circuits with high accuracy using a single unit. It can serve as a measurement foundation for capturing minute pressure changes in cooling water, in applications such as flow path evaluation during cooling system development and design, and verification of cooling efficiency during operation.

Challenges in Designing and Evaluating Cooling Water Circuits

With the growing use of cloud services and AI driving up server processing capacity and heat generation, data center power consumption is drawing significant attention worldwide. Cooling system power consumption also accounts for a significant share of total operating costs, and making cooling systems more efficient, through measures such as adopting water cooling systems and improving PUE (power usage effectiveness), an indicator of operational efficiency, has become an industry-wide challenge.

Growing Cooling System Power Consumption and Operational Efficiency

As server heat generation increases, the power used for cooling has become a major cost factor in data center operation. There is strong demand for designs that reduce the power consumed by the cooling system, such as the drive power of the pumps that circulate cooling water, as a way to improve the facility's overall PUE.

The Difficulty of Evaluating Liquid Cooling Circuits

Making cooling water circuits more efficient requires an accurate understanding of the pressure losses that occur within the circuit. However, many conventional high-accuracy pressure monitors are designed for gases only, and in some cases accuracy is not guaranteed in the low-pressure range for liquids, which limits the measurement options available for evaluating cooling circuits in detail.

Measurement Accuracy Required for Energy-Efficient Design

Improving the efficiency of cooling water circuits requires comparing the slight pressure changes that occur when pipe diameter and flow conditions are varied, in order to judge whether a design is sound. The further efficiency improves, the smaller the absolute values of the pressure losses involved become, making measurement with the resolution and accuracy to support design decisions all the more important.

Solution with the MT300 Precision Pressure Monitor

Direct Differential Pressure Measurement with a Single Unit

The MT300 differential pressure model directly measures differential pressure (ΔP) with a single built-in sensor. In the common method of measuring each pressure with two pressure monitors and calculating the difference, the accuracy of each sensor accumulates (e.g., 0.01% × 2 = 0.02%), which tends to lower the accuracy of the differential pressure measurement. The single-sensor method involves no accuracy accumulation and allows a simple measurement system to be connected to the cooling water circuit, which also contributes to space saving and more efficient data acquisition.

Compatible with Both Liquids and Gases

The MT300 differential pressure model supports both gases and liquids (non-flammable, non-explosive, non-toxic, and non-corrosive fluids) as measurement media. Four ranges are available, 1kPa, 10kPa, 130kPa, and 700kPa, so you can combine the appropriate range and resolution to match the scale of the cooling water circuit and the expected magnitude of pressure loss. While high-accuracy pressure monitors are often limited to gas measurement, the MT300 differential pressure model also supports liquid applications.

Yokogawa's Proprietary Silicon Resonant Sensor

The MT300 is equipped with a silicon resonant sensor developed in-house by Yokogawa. Pressure is applied to resonators formed on a silicon wafer and detected from the resulting change in resonant frequency. A differential method that determines pressure from the difference between the natural frequencies of two resonators cancels out the effects of external conditions such as ambient temperature, achieving both low temperature dependency and high resolution. It has also been adopted as a Transfer Standard for international comparisons of pressure standards, attesting to the sensor's long-term stability.

High-Accuracy Capture of Minute Pressure Losses

The 1kPa differential pressure model, the smallest range, offers a display resolution of 0.00001kPa and a relative accuracy of ±(0.01% of reading + 0.00025kPa). Even as pressure losses become smaller with more efficient cooling circuits, it provides the resolution and accuracy needed to judge whether a design is sound, so it can serve as a measurement foundation for the design evaluation of cooling water systems.

Expected Benefits of Using the MT300

Using the MT300 differential pressure model in data center cooling water systems offers the following potential benefits.

Contributing to Lower Cooling System Power Consumption

Understanding the pressure losses within cooling water circuits with high accuracy makes it possible to identify areas with high flow path resistance and to verify more efficient circuit designs. This leads to optimization aimed at reducing the driving power of cooling pumps and can help lower cooling system power consumption across the entire data center.

Improved Operational Efficiency

Cooling system power consumption is one of the factors that determine a data center's operational efficiency. Evaluating the efficiency of cooling water circuits with high accuracy from the design stage can provide measurement-based support for energy-saving initiatives such as improving PUE and reducing operating costs.

More Efficient Evaluation at the Design Stage

Because differential pressure can be measured directly with a single unit, the evaluation setup for cooling water circuits can be kept simple. Even in development settings where multiple measurement points are evaluated in parallel, the measurement system can be streamlined while maintaining the required accuracy, making design verification more efficient.

Ensuring Reliability Through Long-Term Stable Operation

The MT300 guarantees a relative accuracy of 0.01% for 12 months and offers long-term stability thanks to its silicon resonant sensor. Because accuracy drift between recalibration cycles is small, the MT300 can serve as a reliable long-term measurement foundation for data center cooling system development and ongoing verification work.