Micro-channel heat exchanger

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Solution Overview

Problem

Existing microchannel heat exchangers face challenges in achieving uniform distribution of the heat transfer medium across all channels, leading to uneven heat transfer and significant temperature differences between the primary and secondary sides.

Innovation Solution

The use of a Venturi distributor upstream of the inlet line, combined with capillary lines and a cross-sectional expansion in the connecting section, ensures even distribution of the heat transfer medium to individual microchannel profiles and channels, facilitated by objects like spheres to disrupt the main flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a Venturi distributor is used to distribute heat transfer medium to microchannel profiles, then flow distribution uniformity is improved, but device complexity increases

Engineering Contradiction:
Improveflow distribution uniformityVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system is divided into distinct functional components: Venturi distributor for flow distribution, capillary lines for connection, and connecting sections with cross-sectional expansion at each microchannel profile. This segmentation allows each component to perform its specific function optimally while maintaining overall system uniformity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Capillary lines serve as intermediary elements connecting the Venturi distributor to individual microchannel profiles, enabling controlled flow distribution. The connecting sections with cross-sectional expansion act as intermediaries to further uniformize flow before entering the channels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If capillary lines connect Venturi distributor to microchannel profiles, then flow control is improved, but pressure drop increases

Engineering Contradiction:
Improveflow controlVSAvoidpressure drop
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The cross-sectional area of the connecting section is expanded relative to the capillary line diameter, creating a diffuser effect. This parameter change reduces flow velocity and pressure drop while maintaining flow control precision.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If cross-sectional expansion is added to connecting sections, then flow velocity is reduced and distribution uniformity is improved, but device complexity increases

Engineering Contradiction:
Improvedistribution uniformityVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cross-sectional expansion is implemented only at the connecting sections where needed for flow uniformization, rather than throughout the entire microchannel profile. This partial application achieves the desired effect while minimizing added complexity.

Inventive Principle:
Principle #16Partial or excessive action

4Manufacturing precision

If objects like spheres are placed in connecting sections to disrupt main flow, then flow distribution uniformity is improved, but device complexity increases

Engineering Contradiction:
Improveflow distribution uniformityVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Objects like spheres create a porous-like flow path disruption that distributes flow more uniformly across all channels. This approach achieves uniform distribution without requiring complex internal structures within each channel.

Inventive Principle:
Principle #31Porous materials

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 results in uniform flow through all channels, minimizing temperature differences and enabling optimal operation of the heat exchanger, particularly in heat pumps, with improved efficiency and uniform mixing of gaseous and liquid refrigerant.

Implementation Method 1

A Venturi distributor comprises a centrally located inlet connection and outlet connections, particularly in a star-shaped configuration, extending from the inlet connection. Due to the centrally located outlet connections, all outlet connections have the same pressure drop, so that all outlet connections are flowed through at the same rate.

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Implementation Method 2

By expanding the cross-section of the connection section or diffuser, the flow velocity is reduced to such an extent that the individual channels of the microchannel profiles are each flowed through with the same amount of heat transfer medium.

Methodology Applied
Scientific EffectDiffuser effect:

Implementation Method 3

The outlet connections of the Venturi distributor are connected to the individual microchannel profiles via capillary lines.

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 4

Micro-channel heat exchanger

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 5

ensure good heat transfer with a small temperature spread between the primary side and the secondary side of the heat exchanger

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4575379A1Micro-channel heat exchanger
Publication Date: 2025.06.25 STIEBEL ELTRON GMBH & CO KG
  • EP4575379A1 patent drawingFigure 1
  • EP4575379A1 patent drawingFigure 2
  • EP4575379A1 patent drawingFigure 3~5

AI summary

Heat exchanger (100) with an inlet line (102), an outlet line and a plurality of parallel microchannel profiles (110), wherein the microchannel profiles (110) each have a plurality of channels (112) arranged parallel to one another, wherein a Venturi distributor (104) is arranged between the inlet line (102) and the plurality of parallel microchannel profiles (110) and/or the outlet line (103) and the plurality of parallel microchannel profiles (110), and capillary lines (106) leading from the Venturi distributor (104) to the individual microchannel profiles (110) are arranged, and a connection section (111) is arranged between the respective capillary lines (106) and a respective microchannel profile (110),wherein the connecting section (111) is formed with a cross-sectional widening and an extended connecting cross-section (Aa) of the connecting section (111) opens into the entirety of the individual channels (112) of the respective microchannel profile (110).