Server Rack Cooling via Phase Change Heat Extraction

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Solution Overview

Problem

Current cooling technologies for electronic equipment in server racks face limitations in efficiency and safety concerns, particularly with water-cooling methods, and require complex maintenance procedures due to the presence of cooling components in critical areas.

Innovation Solution

A phase change device with an evaporator and condenser system using a working fluid to efficiently transfer heat from heat-generating units in servers to a fluid cooling unit outside the rack, maintaining the cooling fluid outside the server rack and utilizing a high specific latent heat of vaporization for effective cooling, while keeping the front and backplanes of the rack uncluttered from cooling components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If water-cooling technology is used to cool servers in racks, then cooling efficiency is improved, but safety hazards increase due to potential water leakage and corrosion

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsafety hazards
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the cooling fluid from the server rack environment by using a closed-loop system where the fluid circulates through sealed channels. The evaporator absorbs heat from the server components while the condenser and pump are positioned outside the rack, eliminating the risk of water leakage and corrosion to electronic components while maintaining high cooling efficiency through direct liquid-to-component contact.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state of the cooling fluid by utilizing phase change (evaporation and condensation) to transfer heat. The working fluid evaporates at the evaporator to absorb heat from server components, then condenses at the condenser to release heat externally. This parameter change enables highly efficient heat transfer while keeping the liquid cooling medium contained within a closed system, avoiding safety hazards associated with open water cooling.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If water-cooling units are mounted on heat-generating components, then cooling effectiveness is improved, but device complexity increases due to connection and disconnection difficulties

Engineering Contradiction:
Improvecooling effectivenessVSAvoidconnection complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the cooling system into separate functional modules: an evaporator that attaches to the heat-generating component, conduits for fluid transport, and a condenser-pump assembly positioned externally. This segmentation allows the evaporator to be easily attached/detached from the server component while the main cooling infrastructure remains stationary, simplifying maintenance and server replacement procedures while maintaining effective cooling through dedicated heat transfer pathways.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces flexible conduits as intermediaries to connect the evaporator to the external condenser-pump assembly. These conduits provide mechanical coupling while accommodating movement and misalignment, enabling easy connection and disconnection of cooling components without requiring complex rigid mounting structures or disassembly of the server rack infrastructure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If cooling components are placed in front areas of server racks for airflow, then cooling performance is improved, but ease of operation deteriorates due to blocked access to network connections and backplanes

Engineering Contradiction:
Improvecooling performanceVSAvoidaccess to backplane
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The patent relocates the condenser and pump from the traditional front-facing horizontal plane to a vertical dimension on the side or rear of the server rack. This dimensional change allows cooling components to be positioned in three-dimensional space around the servers rather than competing for front panel real estate, maintaining effective heat dissipation while preserving unobstructed access to network connections, backplanes, and other operational interfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent extracts the bulk of the cooling infrastructure (condenser and pump) from the server rack interior and positions it externally. Only the minimal evaporator component remains within the rack to interface with heat-generating components, while the majority of the cooling system operates from outside the rack environment. This extraction eliminates obstruction of front and rear access points while maintaining cooling performance through the externalized heat rejection and fluid circulation system.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution provides efficient cooling with reduced safety hazards and simplified maintenance by using a phase change device that absorbs heat from servers and transfers it to a fluid cooling unit, maintaining the cooling fluid outside the server rack, thus addressing the inefficiencies and safety concerns of traditional cooling methods.

Implementation Method 1

A phase change device with an evaporator and condenser system using a working fluid to efficiently transfer heat from heat-generating units in servers

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

utilizing a high specific latent heat of vaporization for effective cooling

Methodology Applied
Scientific EffectLatent heat of vaporization: Latent Heat

Implementation Method 3

transfers it to a fluid cooling unit outside the rack

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3829278B1Cooling arrangement for a server mountable in a server rack
Publication Date: 2022.05.18 OVH
  • EP3829278B1 patent drawingFigure 1
  • EP3829278B1 patent drawingFigure 2
  • EP3829278B1 patent drawingFigure 3

AI summary

A cooling arrangement for a server mountable in a server rack comprises a phase change device and a fluid cooling unit. The phase change device includes an evaporator mountable on a heat-generating unit of the server, a condenser disposed outside of the server, and conduits extending laterally from the server, between the evaporator and the condenser. The conduits carry a working fluid heated in the evaporator to the condenser. The working fluid is cooled in the condenser before returning to the evaporator. The fluid cooling unit is positioned along the server rack and receives a cooling fluid from an external cooling facility. A heat transfer module of the fluid cooling unit has an open channel for slidably receiving the condenser. The cooling fluid flows in a water jacket surrounding the open channel. Heat is transferred from the condenser to the cooling fluid flowing in the water jacket.