How to select a pump for electronics cooling

Many OEM engineers are experts in thermal management and system design but may not work with pumps every day. It can be challenging to translate system-level requirements into the specifications and questions that pump manufacturers use when evaluating an application.

This guide is intended to bridge that gap. Below are five key questions that can help inform pump selection for compact liquid cooling systems, covering lifespan, performance, footprint, speed control, and noise, and serves as a useful starting point for evaluating pump options and communicating requirements more effectively.

1. What is the pump's total lifecycle cost?

In many liquid-cooling systems, the pump is one of the few moving components and often operates continuously for years. Selecting a pump designed for long service life and minimal maintenance helps maximize uptime, reduce ownership costs, and minimize service interventions.

Pump characteristics to consider

• BLDC centrifugal motor design: A brushless motor design limits wear, helping lower maintenance requirements while improving efficiency.
• Shaftless ceramic ball-motor architecture: Self-adjusting ceramic bearing construction minimizes wear, while the shaftless rotor reduces maintenance and potential failure points.
• Electronically commutated motor architecture: Electronic commutation reduces electrical and frictional losses, improving efficiency and converting more input power into useful hydraulic work.
• Number of moving components: Fewer moving components mean fewer potential wear and failure points, helping improve reliability and reduce maintenance requirements.
• Continuous-duty design and service life: Supports continuous cooling operation and long-term system reliability by matching pump duty and service life to application requirements.

2. Can the pump maintain adequate flow at the pressure your specific loop demands?

Effective thermal management begins with understanding the cooling performance the system must deliver. The required cooling capacity ultimately determines the flow rate, operating pressure, and duty point the pump needs to achieve.

Pump characteristics to consider

• Coolant flow rate that achieves desired cooling capacity (kW): Ensures adequate coolant flow to meet the system’s heat-removal requirements.
• Operating pressure to overcome system restrictions: Provides the pressure needed to overcome system resistance and maintain the required coolant flow throughout the cooling loop.
• Power consumption at desired performance: Delivers the required flow and pressure while minimizing power consumption and heat generation, supporting overall system efficiency.
• Required flow rate at system pressure: Ensures the pump delivers the required flow at actual system pressure, supporting effective cooling without unnecessary power consumption, heat, noise, or vibration.

3. Will the pump fit within the available space?

As electronics become more compact and power-dense, every cubic centimeter of available space becomes increasingly valuable. Cooling hardware should minimize packaging constraints and preserve space for processors, power electronics, heat exchangers, and other value-generating system components.

Pump characteristics to consider

• Multiple installation orientations and mounting options: Provides greater design flexibility, enabling efficient use of available space without forcing the system layout around the pump.
• Compact pump footprint and connection envelope: Minimizes space required for the pump and its connections, supporting tighter system packaging and greater layout flexibility.
• High hydraulic performance density: Provides greater hydraulic output within a compact footprint, helping enable space-efficient N+1 cooling-loop designs.
• Integrated motor-pump design: Reduces overall installation volume by integrating the motor and pump into a single compact assembly.

4. Does the pump need to accommodate changing cooling demands?

Cooling demands often vary with workload, operating modes, and system conditions. Selecting the appropriate speed-control option allows pump output to be matched to the cooling demand, helping optimize performance, efficiency, and overall system operation.

Pump characteristics to consider

• Control option matched to system requirements: Variable-speed control enables pump output to respond to changing thermal loads, while fixed-speed operation can simplify control for steady-state applications.
• Integrated tachometer feedback: Provides real-time pump-speed feedback in revolutions per minute (rpm) to support pump monitoring and troubleshooting.
• Multiple PWM control profiles: Provides flexible speed control to adjust pump output as cooling demand changes, supporting efficient partial-load operation.
• Electronically commutated motor (ECM) architecture: Provides electronically controlled motor operation that enables precise adjustment of pump speed and output.

5. How will pump noise affect the system?

Many liquid-cooling systems operate near end-users or sensitive equipment where acoustics matter. Minimizing the cooling system's acoustic footprint without sacrificing performance helps improve user experience and system acceptance in noise-sensitive environments. Choosing a pump with quiet operation engineered into the design reduces any resulting vibration and noise, and also reduces the need for later fixes like dampers, isolation features, or enclosure changes.

Pump characteristics to consider

• BLDC centrifugal motor design: Eliminates brush contact and associated friction, helping minimize mechanical noise during operation.
• Shaftless ceramic ball-motor architecture: Minimizes mechanical contact points and potential vibration sources, helping reduce noise during operation.
• Electronically commutated motor (ECM) architecture: Enables precise speed control to meet system demand without unnecessary high-speed operation and associated noise.
• Low acoustic noise output: Minimizes pump-generated acoustic noise, supporting system sound-level requirements in occupied or noise-sensitive environments.

Liquid cooling pumps designed for demanding applications

For over 25 years, Xylem’s D5 and DDC pumps have delivered proven reliability and performance in compact, efficient designs built for demanding liquid cooling applications, including electronics cooling, medical devices, chillers, laser cooling, RV hot water systems, battery cooling, and fuel cells.

Find the right pump for your cooling system

Every cooling system has different requirements. Xylem can help you evaluate your application needs and identify the pump solution that delivers the right balance of performance, efficiency, size, control, and reliability.