Hybrid Air/Liquid Cooling With Shared Fan Temperature Control

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Solution Overview

Problem

Traditional cooling systems for electronic equipment, particularly in data centers, face challenges in managing internal air temperature without the need for dedicated exhaust fans, which increase cost and complexity and can lead to heat buildup due to inefficient liquid cooling circuits.

Innovation Solution

A hybrid air/liquid cooling system with internal fan control, utilizing a refrigerant circuit, air and liquid cooling circuits, and a controller to selectively operate these circuits and fans to manage internal temperature without dedicated exhaust fans, allowing for 100% air cooling, 100% liquid cooling, or a mixture of both, with fans being cycled as needed to exhaust hot air.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a dedicated exhaust fan is used to manage internal air temperature, then the internal temperature can be controlled, but the cost and complexity of the system increase

Engineering Contradiction:
Improveinternal air temperatureVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The fan assembly is designed to serve multiple functions: it acts as both a cooling fan during air cooling operation and an exhaust fan during liquid cooling operation. This multi-functionality eliminates the need for a separate dedicated exhaust fan, reducing system complexity and cost while maintaining effective temperature control in both operating modes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If a dedicated exhaust fan is used to manage internal air temperature, then the internal temperature can be controlled, but the location of other equipment within the unit is constrained

Engineering Contradiction:
Improveinternal air temperatureVSAvoidequipment placement flexibility
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

By designing a single fan assembly that can function as both cooling and exhaust fan through controller-directed operation, the system gains flexibility in equipment placement. The unified fan design removes the constraint of requiring dedicated space for a separate exhaust fan, allowing more flexible arrangement of other equipment within the unit.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If liquid cooling circuit operates continuously, then cooling efficiency is improved, but heat builds up in the unit posing risk to equipment

Engineering Contradiction:
Improvecooling efficiencyVSAvoidheat buildup
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The controller implements periodic operation of the liquid cooling circuit by alternating between air cooling mode and liquid cooling mode. During liquid cooling operation, the same fan assembly is activated as an exhaust fan to periodically expel accumulated heat from the unit. This periodic switching prevents continuous heat buildup while maintaining effective cooling efficiency when liquid cooling is active.

Inventive Principle:
Principle #19Periodic action

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

Effectively maintains internal air temperature within the cooling unit, reducing the need for dedicated exhaust fans and venting, thereby simplifying system design and reducing costs while ensuring efficient thermal management.

Implementation Method 1

an air cooling circuit that includes a first heat exchanger configured to transfer heat from the ambient air to a refrigerant, and a liquid cooling circuit that includes a second heat exchanger configured to transfer heat from a liquid to the refrigerant

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

Traditional liquid cooling circuits include one or more pumps housed within a unit configured to circulate liquid to a cooling distribution unit (CDU) or directly to the electronic equipment

Methodology Applied
Scientific EffectPump circulation: Pump

Implementation Method 3

an air cooling circuit that includes a first heat exchanger configured to transfer heat from the ambient air to a refrigerant, and at least one fan configured to flow air over the at least one first exchanger

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP4642178A1Hybrid air/liquid cooling system with internal temperature control
Publication Date: 2025.10.29 VERTIV CORP
  • EP4642178A1 patent drawingFigure 1
  • EP4642178A1 patent drawingFigure 2
  • EP4642178A1 patent drawingFigure 3

AI summary

A hybrid cooling system includes a refrigerant circuit having at least one first heat exchanger and a liquid cooling circuit having at least one second heat exchanger. A controller operates a valve assembly to selectively flow refrigerant to one or more of the refrigerant and liquid cooling circuits depending on the operating mode of the hybrid cooling system. In embodiments, when the liquid cooling circuit is operative, the controller is configured to implement a control methodology whereby one or more fans associated with the air cooling circuit are powered on to cool at least a portion of the hybrid cooling system, for instance lower an internal temperature in a confined when the hybrid cooling system is implemented as a self-contained unit.