Microchannel Heat Exchanger Folded Tube Segments

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Solution Overview

Problem

Current heat exchangers in HVAC&R systems, particularly condensers and evaporators, face inefficiencies in heat transfer due to limitations in design and configuration, especially when handling high-pressure refrigerants, which affects their performance and operational costs.

Innovation Solution

A microchannel heat exchanger with folded and bent tube segments, configured in a non-linear fashion, allowing for sequential flow through multiple tube banks with discrete flow channels and fins, optimized for high-pressure refrigerants exceeding 750 psig, enabling efficient heat transfer and reduced manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional heat exchange tubes are used, then manufacturing is simpler, but heat transfer efficiency is lower and system performance is reduced

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidtube configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The heat exchange tube is divided into multiple discrete tube segments (first tube segment, second tube segment, third tube segment) with different orientations. Each segment can be independently configured to optimize heat transfer in specific zones, allowing the tube to adapt to varying thermal requirements along its length while maintaining manufacturing feasibility through modular construction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tube transitions from a conventional single-plane configuration to a three-dimensional arrangement with segments oriented at different angles (first segment substantially perpendicular to flow, second segment at first angle, third segment at second angle). This multi-dimensional configuration increases the heat transfer surface area exposure to the refrigerant flow and surrounding environment, significantly improving heat transfer efficiency

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

2Area of stationary object

If tube depth is increased, then heat transfer surface area is larger, but manufacturing complexity and tooling requirements increase

Engineering Contradiction:
Improveheat transfer surface areaVSAvoidmanufacturing tooling complexity
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The tube is segmented into multiple sections with different orientations and configurations. Each segment can be manufactured using standard tools and then assembled to form the complete multi-dimensional structure, avoiding the need for complex single-piece manufacturing tools while achieving large total surface area

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tube incorporates bends and angular transitions between segments rather than sharp 90-degree corners. These curved transitions distribute manufacturing stresses and can be formed using conventional bending tools, maintaining ease of manufacture while creating the multi-dimensional surface area needed for efficient heat transfer

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Power

If high-pressure refrigerant is used, then system capacity is increased, but structural integrity requirements are more stringent

Engineering Contradiction:
Improvesystem capacityVSAvoidtube structural integrity
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

Dividing the tube into segments allows each section to be optimized for its specific pressure and thermal conditions. The segmentation creates natural stress distribution points and allows for localized reinforcement where needed, maintaining structural integrity under high-pressure operation while enabling increased system capacity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bent and angled configurations of the tube segments distribute mechanical stresses more evenly throughout the structure compared to straight rigid tubes. The curved transitions and angular joints act as stress relief features, preventing stress concentration that could lead to failure under high-pressure refrigerant operation

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 transfer efficiency and structural integrity for high-pressure refrigerants, allowing for flexible configuration without altering manufacturing tools, thereby improving system performance and reducing costs.

Implementation Method 1

heat exchange tube segments arranged in spaced parallel relationship and fluidly coupling the first manifold and the second manifold

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

sequential flow there through of a first heat transfer fluid

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a fold forming a first tube bank and a second tube bank parallel to one another wherein the first tube bank and the second tube bank are configured for sequential flow there through

Methodology Applied
Scientific EffectFluid flow redirection:

Data Source

PatentEP3334991B1Microchannel heat exchanger
Publication Date: 2020.09.30 CARRIER CORP
  • EP3334991B1 patent drawingFigure 1~2
  • EP3334991B1 patent drawingFigure 3
  • EP3334991B1 patent drawingFigure 4~5

AI summary

A heat exchanger is provided including a first manifold, a second manifold separated from the first manifold, and a plurality of heat exchange tube segments arranged in spaced parallel relationship and fluidly coupling the first manifold and the second manifold. The plurality of heat exchange tube segments include a fold forming a first tube bank and a second tune bank in substantially parallel relation to one another along at least a portion of a length of the plurality of heat exchange tube segments. The first tube bank and the second tube bank are configured for sequential flow there through of a first heat transfer fluid.