Abstract

As rack power density in data centers exceeds 30 kW, energy storage systems scale toward GWh levels, and EV fast-charging power moves toward 600 kW, liquid cooling has become the core thermal management solution for high-power-density equipment. This report systematically analyzes coolant selection logic and flow sensor compatibility across five major application scenarios: data centers, energy storage, EV battery thermal management, charging stations, and industrial automation. It also examines the unique advantages of ultrasonic flowmeters in liquid cooling systems. The study concludes that ultrasonic flowmeters, with their non-contact measurement, broad medium compatibility, zero pressure loss, and absence of moving parts, are becoming the ideal choice for flow monitoring in liquid cooling applications.

1.Liquid Cooling Technology

Liquid cooling technology is rapidly gaining adoption across high-power-density industries due to its superior heat transfer performance. From traditional data centers to emerging energy storage systems, from electric vehicles to ultra-fast charging stations, liquid cooling has evolved from an “optional solution” to a “mandatory technology.”

1.1 Market Scale and Key Drivers

According to the Panoramic Research on the Liquid Cooling Industry in Intelligent Computing Centers released by the China Academy of Information and Communications Technology (CAICT) in 2025, the penetration rate of liquid cooling in intelligent computing centers is expected to exceed 40% in 2025 and continue to grow rapidly. 

Key driving factors include:

1)Explosive growth in AI computing demand: Single GPU chip power consumption has risen from 400 W in 2020 to over 1000 W today

2)Stricter PUE regulations: China’s “East Data, West Computing” policy imposes mandatory energy efficiency requirements on data centers.

3)Upgraded safety standards for energy storage: Liquid cooling systems have become standard in large-scale energy storage stations.

4)Ultra-fast charging technology advancement: 600 kW+ liquid-cooled ultra-fast charging stations are being deployed at an accelerated pace.

2. In-Depth Analysis of Mainstream Coolant

As the core heat transfer medium in liquid cooling systems, coolant selection directly affects system efficiency, safety, and maintenance costs. The following analysis examines the four major coolant types from the perspectives of technical characteristics, application scenarios, and advantages/disadvantages.

2.1 Comparison of Four Mainstream Coolant Types

2.2 Key Considerations for Coolant Selection

In practical engineering applications, coolant selection requires comprehensive evaluation of the following factors:

1)Thermal Performance: Specific heat capacity and thermal conductivity determine heat absorption per unit temperature rise and heat exchange efficiency.

2)Fluid Properties: Viscosity directly affects pump power consumption and pipeline pressure drop; density influences inertial load。

3)Safety Level: Conductivity determines the risk of damage to electronic equipment in case of leakage.

4)Environmental Adaptability: Freezing and boiling points define the applicable temperature range.

5)Material Compatibility: Must be compatible with all wetted materials (pipes, seals, sensors) over the long term.

6)Maintenance Cost: Service life, replacement cycle, and frequency of additive replenishment.

3. In-Depth Analysis of Five Core Application Scenarios

3.1 Data Center Liquid Cooling

Scenario Characteristics and Coolant Selection
Data centers is highly demanding for liquid cooling. With AI computing demand surging, rack power density has increased from the traditional 10–20 kW to 30–50 kW, rendering air cooling insufficient. According to ZTE’s Liquid Cooling Technology White Paper (2022), liquid cooling has become essential for high-density data centers to achieve efficient heat dissipation and carbon neutrality goals.

Cold-plate liquid cooling (indirect): Coolant does not contact servers directly; heat is removed via cold plates.

Immersion liquid cooling (direct): Servers are fully submerged in dielectric coolant.

Flow Sensor Selection Considerations
According to VEGA’s 2025 sensor selection guide, key requirements include high measurement accuracy, low pressure loss, digital communication (IO-Link), and material compatibility (316L stainless steel).

3.2 Energy Storage System Liquid Cooling

Large-scale electrochemical energy storage stations have extremely stringent thermal management requirements. Lithium-ion batteries perform optimally at 25–35°C with temperature differences controlled within 5°C. Liquid cooling systems, primarily using ethylene glycol solutions (25%–50%), have become the standard configuration. Typical flow rates range from 2–8 L/min per battery cluster, with total system flow reaching hundreds of L/min.

3.3 EV Battery Thermal Management

Liquid cooling has become the mainstream technology for EV battery thermal management, with penetration exceeding 60%. Key coolant requirements include low toxicity, wide temperature range (-40°C to 60°C), long service life (8–10 years), and low conductivity. Typical flow rates are 1–5 L/min per module and 4–20 L/min for the system.

3.4 Charging Station Liquid Cooling

Liquid-cooled ultra-fast charging (400–600 kW+) uses specialized dielectric coolants (oil-based or synthetic esters) to keep charging gun and connector temperatures below 50°C. Flow monitoring is critical to prevent cooling failure.

3.5 Industrial Automation Liquid Cooling

Applications include CNC machines, laser processing, welding equipment, industrial robots, and injection molding machines. Coolants are used for cutting fluid monitoring, hydraulic oil flow, lubrication systems, and high-power laser cooling.

4. Comparison of Flow Sensor / Flow Meter Technologies

4.1 Comparison of Mainstream Flow Sensor / Flow Meter  Technologies

4.2 Impact of Coolant Conductivity on Flow Sensor Selection

5. Unique Advantages of Ultrasonic Flowmeters in Liquid Cooling Systems

Ultrasonic flow sensors / flow meters demonstrate significant advantages in liquid cooling applications due to their unique measurement principle. They are compatible with deionized water, ethylene glycol, and non-conductive fluids.

5.1 Ultrasonic Flow Sensor / Flow Meter Technical Advantages

1.Capability to Measure Non-Conductive Coolants

Ultrasonic flowmeters operate on the transit-time difference technology and are independent of fluid conductivity, making them an ideal option for dielectric fluids flow rate measurement  in immersion cooling.

2.Wide Temperature Range

Industrial-grade models typically support 0°C to 90°C, with some specialized versions covering -40°C to 200°C.

3.Non-Contact Flow Rate Measurement – Zero Leakage Risk

The CPD Clamp-on flow sensors / flow meters can be installed externally on the rigid plastic tubing wall, requiring no tube cutting or system shutdown and introducing no new leakage points.

4.Extremely Low Pressure Loss – Energy Efficient

No obstruction in the flow path, helping reduce pump energy consumption and improve PUE.

5.No Moving Parts – Long-Term Reliability

Eliminates wear-related drift, ideal for 24/7 continuous operation in data centers and energy storage systems.

6.Flexible Installation – Ideal for Retrofit Projects

Clamp-on flow sensor / flow meters enable deployment without disrupting existing pipelines, particularly valuable in “air cooling to liquid cooling” retrofit projects.

5.2 XY-TEK Ultrasonic Flow Sensor / Flow Meter  for Liquid Cooling 

CPD series Clamp on Flow Sensor / Flow Meter 

The CPD series clamp-on ultrasonic flow sensor/flow meters boast a compact design with an integrated display and circuit system, facilitating seamless flow measurement and intuitive data monitoring.

Designed for easy clamping onto rigid plastic tubing, the CPD series clamp-on ultrasonic flow sensor/flow meters delivers an accuracy of up to ±2%.

Furthermore, it can detect bubbles and solid particles within the liquid.

With the non-invasive design, the CPD series ultrasonic flow sensor/flow meter guarantees that no flow contamination occurs during the measurement process.The CPD flow sensor / flow meter supports non-invasive flow rate measurement of water, pure water, cleaning water, acids, chemical, CMP slurry, oil, beverages, alcohols, etc.

It is particularly well-suited for applications requiring stringent hygiene and cleanliness standards, such as biopharmaceuticals, medical devices, and industrial automation.

TPD series in-line Ultrasonic Flow Sensor / Flow Meter

The TPD series inline ultrasonic flow sensors/flow meters feature an integrated design with a built-in circuitry, support direct flow rate measurement and intuitive flow data monitoring, ideal for industrial automation, battery manufacturing equipment, water treatment, and liquid cooling flow rate measurement.

Tubing Range DN15-DN50, support OEM and tubing size customization.

The TPD series inline ultrasonic flow sensors/flow meters can be integrated into the existing fluid systems through internationally standardized tubing fittings, with an accuracy of up to ±2%.

TPD series inline ultrasonic flow sensors/flow meters consist of straight tubing with no moving parts and dead spots, making it resistant to wear and scaliness, easy to clean, and with minimal pressure loss.

Compared to clamp-on ultrasonic flow sensors/flow meters, the TPD series flow sensor/flow meters calibration does not depend on the tubing material and diameter, enabling immediate measurement upon integration into the system.

The TPD flow sensor/flow meters are widely used in filling and spraying applications, battery manufacturing devices, liquid cooling, industrial automation systems, and more.

5.3 Ultrasonic Flow Sensor Selection Guide: Clamp-on vs. In-line Ultrasonic Flowmeters

Type	Clamp-on Ultrasonic Flowmeter	In-line Ultrasonic Flowmeter
Installation Method	Clamped externally on tubing wall	Connect to the tubing via fitting or connectors
Applicable Pipe Size	6 mm – 24 mm	DN2 – DN50
Accuracy	±1% ~ ±2% RD	±1% ~ ±2% RD (typically higher)
Pressure Loss	Zero	Very low
Recommended Scenarios	Retrofit projects, existing pipelines, non-invasive measurement	Share on social platforms Return List Prev: NO Next: Selective Wave Soldering Flux Flow Measurement---TGU series Ultrasonic Flow Sensor Hot Recommendation TGD series In-line Ultrasonic Flow Sensor Advantages Inquiry Submit Have questions or need assistance? Contact us-we're here help! Your Name * Company * Your Email * Phone Number(Optional) Message * 86-21-33885752 global@xy-tek.cn ；info@xy-tek.cn Building 7, No.410 Jinggu Road, Minhang District, Shanghai, 200245，China Products Medical Bioprocess New Energy Industrial Automation Accessories Applications Medical Bioprocess New Energy Industrial Automation Case Study Resources Document Center FAQ Blog News Events Company News Company About Us Awards Join Us Contact Us All rights reserved © Shanghai Xunyin Technology Co., Ltd Pre-Sale Email: global@xy-tek.cn ；info@xy-tek.cn After-Sale