Bypass Pipe Refrigerant Distribution for Cooling Systems

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Solution Overview

Problem

The initial operation of refrigerant natural circulation cooling systems experiences reduced cooling performance due to uneven refrigerant distribution and slow circulation, leading to blocked vapor flow and prolonged time to reach maximum heat transport capacity.

Innovation Solution

The electronic apparatus cooling system incorporates a bypass pipe connecting the vapor and liquid pipes, allowing for efficient refrigerant circulation by redirecting accumulated liquid refrigerant back to the liquid pipe, ensuring all heat receiving portions are filled with refrigerant quickly, thus preventing vapor flow obstruction and accelerating system operation to maximum capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If refrigerant natural circulation cooling system is used, then electric power consumption for air conditioning is reduced, but cooling performance is lowered at initial stage of operation

Engineering Contradiction:
Improveelectric power consumptionVSAvoidcooling performance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a pump that operates before natural circulation begins to preliminarily distribute refrigerant to all heat receiving portions. This preliminary action ensures that refrigerant is present in all necessary locations before the system transitions to energy-efficient natural circulation, thereby maintaining cooling performance while reducing power consumption during steady-state operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pump serves as an intermediary device that bridges the transition between system startup and natural circulation operation. It temporarily provides the driving force needed for refrigerant distribution, after which natural circulation takes over, combining the benefits of reliable initial cooling with low operational energy consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If refrigerant natural circulation cooling system is used, then electric power consumption for air conditioning is reduced, but time to reach maximum heat transport capacity is prolonged

Engineering Contradiction:
Improveelectric power consumptionVSAvoidtime to reach maximum heat transport
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The pump performs preliminary refrigerant distribution to all heat receiving portions before natural circulation begins. This preliminary action significantly reduces the time required for the system to reach maximum heat transport capacity, while the system subsequently operates in energy-efficient natural circulation mode.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pump operates continuously during startup to ensure all heat receiving portions are filled with refrigerant, maintaining continuous useful action for heat transport. After startup, the system transitions to natural circulation, combining continuous cooling with reduced energy consumption.

Inventive Principle:
Principle #20Continuity of useful action

3Use of energy by moving object

If refrigerant natural circulation cooling system is used, then electric power consumption for air conditioning is reduced, but vapor flow is blocked by accumulated liquid

Engineering Contradiction:
Improveelectric power consumptionVSAvoidvapor flow blockage
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The pump preliminarily distributes refrigerant evenly to all heat receiving portions, preventing excessive liquid accumulation in any single location. This preliminary distribution eliminates the condition that causes vapor flow blockage, allowing natural circulation to operate without harmful liquid accumulation while maintaining low power consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pump, which consumes energy, converts the potential harm of uneven refrigerant distribution (which would cause vapor blockage) into a benefit by ensuring uniform distribution. This allows the natural circulation system to operate without the harmful effects of liquid accumulation blocking vapor flow.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 configuration enhances initial operation efficiency by preventing refrigerant accumulation blockages and ensures rapid refrigerant distribution, reducing performance degradation and the time to achieve maximum heat transport, thereby optimizing cooling performance.

Implementation Method 1

the phase of the refrigerant changes from liquid to vapor and the vapor (vapor-phase refrigerant) flows to the cooling towers

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a large amount of heat transfer can be realized because latent heat is used

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 3

the refrigerant changes to refrigerant liquid (liquid-phase refrigerant) and the liquid-phase refrigerant flows back to the evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

heat exhausted from the electronic apparatus mounted in a server rack is transported to an evaporator mounted on a rack back face via refrigerant

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3073813B1Electronic apparatus enclosure device and electronic apparatus cooling system
Publication Date: 2020.07.22 NEC CORP
  • EP3073813B1 patent drawingFigure 1
  • EP3073813B1 patent drawingFigure 2
  • EP3073813B1 patent drawingFigure 3~4

AI summary

A vapor pipe 103 connects a heat dissipation portion 200 and each of a plurality of heat receiving portions 102. A liquid pipe 104 connects the heat dissipation portion 200 and each of a plurality of the heat receiving portions 102. A bypass pipe 105 connects the vapor pipe 103 and the liquid pipe 104. A valve 106 opens and closes a flow path of the bypass pipe 105. A first connection portion 107 connects the vapor pipe 103 and the bypass pipe 105. A second connection portion 108 connects the liquid pipe 103 and the bypass pipe 105. The first connection portion 107 is disposed at a position higher than that of the second connection portion 108. As a result, refrigerant can be efficiently transported in a short time.