Multi-Metal Heat Exchanger Structure With Lower Thermal Resistance

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Solution Overview

Problem

Conventional heat exchangers face issues with thermal resistance due to joining layers, voids in brazing, increased weight with materials like copper or stainless steel, complex manufacturing due to precise temperature control, and difficulty in joining different metals such as copper and aluminum.

Innovation Solution

The heat exchanger features refrigerant passages with inner wall surfaces of different metals, where the first refrigerant passages are formed with penetrating holes instead of header pipes, and second refrigerant passages are made of metal different from the heat transfer block, allowing for easier manufacturing and improved corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If header pipes are used to connect refrigerant passages, then structural integrity is improved, but manufacturing complexity increases and thermal resistance increases

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the header pipe function with the heat transfer block by forming refrigerant passage communicating holes directly in the heat transfer block. This integration eliminates the need for separate header pipes and their associated joining processes, thereby reducing manufacturing complexity while maintaining structural integrity through the unified block structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the header pipe component from the system by forming communicating holes directly in the heat transfer block. This removal of the separate header pipe component eliminates the joining layer and associated thermal resistance, while the communicating holes provide the necessary refrigerant flow paths.

Inventive Principle:
Principle #2Taking out (Extraction)

2Strength

If brazing is used to join heat transfer tubes, then connection strength is improved, but thermal resistance increases due to joining layer and voids

Engineering Contradiction:
Improveconnection strengthVSAvoidthermal resistance
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent extracts the separate heat transfer tubes and their brazing joints from the system. Instead, refrigerant passages are formed directly in the heat transfer block with inner wall surfaces, eliminating the joining layer and associated thermal resistance while maintaining connection integrity through the integrated structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the heat transfer tube function with the heat transfer block by forming passages directly in the block. This integration eliminates the interface between separate components, removing the thermal resistance caused by joining layers and voids, while the inner wall surfaces of the passages provide the necessary heat transfer interface.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If copper or stainless steel is used for heat transfer tubes, then corrosion resistance is improved, but weight increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidheat exchanger weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies different materials to different parts of the heat exchanger based on local requirements. The heat transfer block can be made from lighter materials while specific regions with inner wall surfaces provide corrosion resistance where needed, optimizing the weight-strength-corrosion resistance balance through localized material properties.

Inventive Principle:
Principle #3Local quality

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 heat exchange performance by reducing thermal resistance, simplifies manufacturing, and addresses corrosion issues, while enabling the use of metals with improved thermal conductivity and reduced weight.

Implementation Method 1

a heat transfer block (1), in which a plurality of first-refrigerant passages (2), through which a first refrigerant passes, are formed so as to penetrate the heat transfer block (1)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2706318B1Heat exchanger and refrigeration cycle device provided with same
Publication Date: 2016.03.30 MITSUBISHI ELECTRIC CORP
  • EP2706318B1 patent drawingFigure 1(a)~1(c)
  • EP2706318B1 patent drawingFigure 2(a)~2(d)
  • EP2706318B1 patent drawingFigure 3(a)~3(c)

AI summary

To obtain a heat exchanger in which inner wall surfaces of refrigerant passed through which a first refrigerant and a second refrigerant flow are constituted by a different metal and in which a heat exchange performance is improved. Second-refrigerant heat-transfer tubes (3a) that are formed with a metal different from a heat transfer block (1) are each passed through a corresponding second-refrigerant heat-transfer-tube insertion hole (3b), the second-refrigerant heat-transfer tubes (3a) are formed with a metal with a different material from that of the heat transfer block (1).