Integrated Suction Gas Heat Exchanger for Low-Refrigerant Cooling

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Solution Overview

Problem

Existing refrigeration systems face inefficiencies in suction gas heat exchange due to costly piping requirements and co-current heat exchange, which can lead to refrigerant volume increase and potential compressor damage from droplet formation.

Innovation Solution

A brazed plate heat exchanger with integrated suction gas heat exchanger portions, utilizing ridges and grooves to form interplate flow channels and selective port openings, allowing for counter-current heat exchange without separate components, thus reducing refrigerant volume and minimizing droplet formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate heat exchanger is provided for suction gas heat exchange, then heat exchange efficiency is improved, but device complexity and refrigerant volume increase

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The suction gas heat exchange function is merged with the evaporator and condenser by providing a heat exchange portion integrated into these components. The heat exchange portion includes a first portion connected to the evaporator and a second portion connected to the condenser, forming a unified structure that performs both evaporation/condensation and suction gas heat exchange functions, thereby eliminating the need for a separate heat exchanger.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchange portion is designed to serve multiple functions: it acts as part of the evaporator for cooling mode, part of the condenser for heating mode, and simultaneously provides suction gas heat exchange by connecting to both components. This multi-functionality reduces the overall number of components while maintaining all necessary heat exchange capabilities.

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

2Reliability

If piping is extended to connect evaporator and condenser for suction gas heat exchange, then heat exchange is achieved, but refrigerant volume increases

Engineering Contradiction:
Improvesuction gas heat exchangeVSAvoidrefrigerant volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The heat exchange portion is integrated directly into the evaporator and condenser structures, eliminating the need for extended piping to connect separate components. By merging the heat exchange function into the existing components through direct connection, the refrigerant path is shortened and refrigerant volume is reduced while maintaining effective suction gas heat exchange.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If co-current heat exchange is used in heating and cooling modes, then system operation is simplified, but heat exchange performance decreases leading to droplet formation

Engineering Contradiction:
Improvesystem operation simplicityVSAvoidheat exchange performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The heat exchange portion is designed to enable counter-current heat exchange by reversing the flow direction relationship between the first and second portions. In the evaporator, the first portion receives refrigerant from the compressor while the second portion receives refrigerant from the heat source. In the condenser, the flow directions are reversed. This counter-current arrangement maximizes heat exchange performance and prevents droplet formation while maintaining operational simplicity through the integrated design.

Inventive Principle:
Principle #13The other way round (Inversion)

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

The solution enhances heat exchange efficiency and reduces refrigerant volume while preventing compressor damage by integrating suction gas heat exchange, maintaining performance in both heating and cooling modes.

Implementation Method 1

heat exchanger plates provided with a pressed pattern of ridges and grooves adapted to keep the plates on a distance from one another by providing contact points between crossing ridges and grooves of neighbouring plates under formation of interplate flow channels for media to exchange heat

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

interplate flow channels for media to exchange heat

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

heat exchange between warm liquid, high pressure refrigerant from a condenser outlet and cold gaseous refrigerant from an evaporator outlet. By the suction gas heat exchange, the temperature of the cold gaseous refrigerant will increase

Methodology Applied
Scientific EffectHeat exchange: Convection

Data Source

PatentEP3631341B1Heat exchanger having an integrated suction gas heat exchanger
Publication Date: 2026.01.14 SWEP INT AB
  • EP3631341B1 patent drawingFigure 1a~1c
  • EP3631341B1 patent drawingFigure 2
  • EP3631341B1 patent drawingFigure 3

AI summary

A brazed plate heat exchanger (100; 200) comprises a number of heat exchanger plates (120a-120h; 201-204) provided with a pressed pattern of ridges (R) and grooves (G) adapted to keep the plates on a distance from one another by providing contact points between crossing ridges (R) and grooves (G) of neighbouring plates under formation of interplate flow channels for media to exchange heat, said interplate flow channels being in selective fluid communication with first, second, third and fourth large port openings (O1, O2, O3, O4; 210a, 210b, 210c, 210d) and first and second small port openings (SO1, SO2) for letting in fluids to exchange heat, characterized in that fluid passing between the first and second large port openings (O1, O2; 210a, 210b) exchanges heat with fluids passing between third and fourth port openings (O3, O4; 210c, 210d) over a first heat exchanging portion of each plate and fluid passing between the first and second small port openings (SO1, SO2) over a second portion of each plate.