Multi-Core Heat Exchanger Header for Uniform Refrigerant Distribution

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Solution Overview

Problem

Heat exchangers with multiple cores experience limited heat exchange efficiency due to uneven refrigerant distribution, with the header and tube structure from existing patents failing to adequately distribute refrigerant to heat exchanger cores on both the windward and leeward sides, leading to inefficient heat exchange.

Innovation Solution

A heat exchanger design with a distributor having multiple refrigerant flow paths, where heat transfer tubes on the windward side are connected to upstream paths and those on the leeward side to downstream paths, along with a refrigeration cycle apparatus featuring a second refrigerant circuit with a flow control valve to adjust refrigerant flow, ensuring higher refrigerant flow rates to the windward side heat exchanger core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single header pipe structure is used to distribute refrigerant to multiple heat exchanger cores, then the device complexity is reduced, but the refrigerant distribution uniformity deteriorates causing limited heat exchange efficiency

Engineering Contradiction:
Improveheader structureVSAvoidheat exchange efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The single header pipe is segmented into multiple independent flow paths within the header body. Each flow path independently distributes refrigerant to specific heat exchanger cores, enabling differentiated flow control while maintaining a unified header structure. This segmentation resolves the contradiction by allowing efficient refrigerant distribution without increasing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the header body provide different flow characteristics to different heat exchanger cores. The header creates localized flow conditions optimized for each core's position (windward vs. leeward), ensuring each core receives appropriate refrigerant flow. This local quality approach improves heat exchange efficiency while keeping the header structure integrated.

Inventive Principle:
Principle #3Local quality

2Device complexity

If refrigerant flows through a long path from header to heat exchanger cores, then the device complexity is reduced, but the refrigerant flow rate to windward side cores deteriorates reducing heat exchange efficiency

Engineering Contradiction:
Improverefrigerant flow pathVSAvoidrefrigerant flow rate
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The refrigerant flow path is segmented into multiple parallel channels within the header body. This creates shorter, more direct flow paths to different heat exchanger cores, particularly improving refrigerant delivery to windward side cores. The segmentation maintains a simple overall device structure while significantly improving refrigerant flow rate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The header body introduces a three-dimensional flow path structure with multiple channels at different spatial levels. This dimensional approach allows refrigerant to reach windward side cores more directly without extending the overall device length, resolving the contradiction between simple device structure and high refrigerant flow rate.

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

3Ease of manufacture

If the header structure is simplified to reduce device complexity, then manufacturing becomes easier, but the ability to equally distribute refrigerant to all heat exchanger cores deteriorates

Engineering Contradiction:
Improveheader structureVSAvoidrefrigerant distribution uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The header incorporates segmented flow paths as an integrated manufacturing unit. This allows complex refrigerant distribution functionality to be achieved through a single manufactured component rather than multiple assembled parts, maintaining ease of manufacture while ensuring precise and uniform refrigerant distribution to all cores.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The header body serves multiple functions simultaneously: it distributes refrigerant to multiple cores, creates differentiated flow paths for different core positions, and maintains structural integrity. This multi-functionality achieves precise refrigerant distribution without requiring multiple separate components, preserving manufacturing simplicity.

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

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 design enhances heat exchange efficiency by preferentially distributing liquid refrigerant to the windward side heat exchanger core, improving temperature differences and overall heat transfer performance.

Implementation Method 1

with the effect of gravity, a liquid refrigerant flows to a lower portion of the header at a high flow rate

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

a heat exchanger that allows air and refrigerant to exchange heat therebetween

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

multiple heat exchanger cores including multiple heat transfer tubes arranged side by side and multiple fins

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3647682B1Heat exchanger and refrigeration cycle device
Publication Date: 2021.06.30 MITSUBISHI ELECTRIC CORP
  • EP3647682B1 patent drawingFigure 1~2
  • EP3647682B1 patent drawingFigure 3~4
  • EP3647682B1 patent drawingFigure 5~6

AI summary

A heat exchanger includes multiple heat exchanger cores and a distributor that distributes refrigerant. The heat exchanger core includes multiple fins and multiple heat transfer tubes arranged vertically. The multiple heat transfer tubes are connected to the distributor. The inside of the distributor is divided into multiple refrigerant flow paths. The distributor allows the refrigerant flowing into one of the multiple refrigerant flow paths to flow from the one of the refrigerant flow paths to another one of the refrigerant flow paths. The multiple heat transfer tubes of one of the multiple heat exchanger cores disposed on a windward side of a flow of the air fed to the heat exchanger are connected to at least one of the refrigerant flow paths disposed in the distributor on an upstream side of a flow of the refrigerant. The multiple heat transfer tubes of one of the multiple heat exchanger cores disposed on a leeward side of the flow of the air fed to the heat exchanger are connected to at least one of the refrigerant flow paths disposed in the distributor on a downstream side of the flow of the refrigerant.