PCB Cooling Member Routing for Liquid Heat Rejection

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Solution Overview

Problem

Existing server cooling systems face inefficiencies due to excessive heat dissipation into the air, leading to increased power consumption, noise, vibrations, and reduced cooling fan reliability, as they work harder to expel heat and compete for air space.

Innovation Solution

A hybrid cooling system that routes a cooling member along the under surface of a printed circuit board to deliver liquid to and from electrical components, maximizing heat rejection into the liquid by crossing the midpoint between surfaces, thereby reducing the load on air cooling and minimizing the number of cooling fans required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If air cooling is used to dissipate heat from electrical components, then heat can be removed from the components, but cooling fans must work harder leading to increased power consumption, noise, and reduced reliability

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidpower consumption of cooling fans
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The cooling system is segmented into two independent pathways: liquid cooling channels embedded in the PCB substrate for targeted heat removal, and air cooling fans for general ambient cooling. This segmentation allows the liquid cooling to handle the majority of heat dissipation efficiently, reducing the burden on air cooling fans and their power consumption

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces liquid cooling channels that circulate coolant through the PCB substrate to directly absorb heat from electrical components. This hydraulic cooling method is significantly more efficient than air cooling, allowing heat to be removed with minimal or no fan operation, thereby reducing power consumption, noise, and vibration

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If more cooling fans are used to improve cooling capacity, then heat dissipation improves, but the number of fans increases leading to more noise, vibrations, and reduced reliability

Engineering Contradiction:
Improveheat dissipation capacityVSAvoidcooling fan reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The liquid cooling system provides efficient heat removal through circulated coolant, eliminating the need for multiple high-speed air cooling fans. Fewer fans operating at lower speeds result in reduced mechanical failures, less noise, and lower vibrations, thereby improving overall system reliability

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If cooling fans operate at higher speeds to dissipate more heat, then cooling efficiency improves, but power consumption increases and reliability decreases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcooling fan reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The liquid cooling channels provide high-efficiency heat removal through direct thermal contact with the coolant flow. This allows the system to maintain excellent cooling performance with fans operating at minimal or zero speed, significantly improving reliability by eliminating the wear and failure modes associated with high-speed fan operation

Inventive Principle:
Principle #29Pneumatics and hydraulics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach decreases heat dissipation into the air, allowing cooling fans to operate at lower speeds, increases reliability, reduces power consumption, and supports a greater array of server configurations by minimizing the number of fans needed and the space they occupy.

Implementation Method 1

deliver liquid to and from an electrical component on a top surface of the board... Maximizing the amount of heat rejected into the liquid of the cooling member

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

Maximizing the amount of heat rejected into the liquid of the cooling member... decreases heat dissipation into the air

Methodology Applied
Scientific EffectHeat rejection: Convection

Data Source

PatentEP3266290B1Routing a cooling member along a board
Publication Date: 2023.03.22 HEWLETT PACKARD ENTERPRISE DEV LP
  • EP3266290B1 patent drawingFigure 1A~1B
  • EP3266290B1 patent drawingFigure 2A~2B
  • EP3266290B1 patent drawingFigure 3A~3B

AI summary

Examples herein disclose a system including a board and a cooling member. The board includes a first surface, a second surface, and a midpoint between the first and the surface, the boards supports an electrical component on the first surface. The cooling member is routed along the second surface of the board and delivers cooling liquid to the electrical component by crossing the midpoint of the board from the second surface to the first surface. The cooling member routes heated liquid from the electrical component by crossing the midpoint of the board from the first surface to the second surface.