Cross-Fin Heat Exchanger Layout for Uneven Airflow Matching

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Solution Overview

Problem

Conventional cross fin-type heat exchangers face challenges in finely adjusting heat exchanging performance across different portions due to non-uniform air flow characteristics, leading to inefficient heat transfer in varying air flow conditions.

Innovation Solution

The heat exchanger design incorporates a combination of fins, tube plates, refrigerant tubes with varying heat transfer and bent portions, a flow divider, and a header, allowing for even and odd numbers of heat transfer tube portions in refrigerant tubes, with branching tubes connected differently to optimize flow channel lengths and pressure losses for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional cross fin-type heat exchanger is used, then the structure is simple and easy to manufacture, but the heat exchanging performance cannot be finely adjusted for each portion due to non-uniform air flow

Engineering Contradiction:
Improveheat exchanging performance adjustment precisionVSAvoidheat exchanger structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The heat exchanger is divided into multiple sections along the air flow direction, with each section having independently adjustable refrigerant tube configurations. The refrigerant tubes are segmented into multiple heat transfer tube portions with different numbers of fins in each portion, allowing localized adjustment of heat transfer characteristics to match varying air flow conditions across different sections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the refrigerant tubes are designed with different numbers of heat transfer tube portions (even or odd numbers) to create local variations in heat exchanging performance. This local quality differentiation allows each section of the heat exchanger to be optimized for its specific air flow characteristics, with sections experiencing higher air flow having different tube configurations compared to sections with lower air flow.

Inventive Principle:
Principle #3Local quality

2Productivity

If the refrigerant tubes have uniform structure throughout, then the manufacturing is simple, but the heat exchanging performance varies inefficiently across portions with different air flow characteristics

Engineering Contradiction:
Improveheat exchanging efficiencyVSAvoidrefrigerant tube configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The refrigerant tube configuration is made dynamically adaptable to varying air flow conditions by incorporating sections with different numbers of heat transfer tube portions. This dynamic design allows the heat exchanger to automatically optimize heat transfer efficiency across different operational conditions without requiring active control mechanisms, as the structural variations inherently respond to air flow distribution patterns.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The physical parameters of the refrigerant tubes are changed along their length, specifically the number of heat transfer tube portions (even or odd numbers), to optimize heat exchanging efficiency. By varying these structural parameters in response to air flow characteristics, the system achieves higher overall productivity without requiring complex external control systems.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If path count modifying means is used to adjust refrigerant distribution, then heat exchanging performance in cooling and heating operations is improved, but fine adjustment for each portion in response to air flow variation is still difficult

Engineering Contradiction:
Improveheat exchanging performance fine adjustment capabilityVSAvoidflow control system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of using a complex flow control system, the patent segments the refrigerant tubes into multiple heat transfer tube portions with different configurations (even or odd numbers) distributed throughout the heat exchanger. This segmentation allows each portion to be independently optimized for its local air flow conditions, achieving fine adjustment capability without requiring additional flow control mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heat exchanger structure itself provides the flow distribution optimization through its varied tube configurations rather than requiring an external flow control system. The different numbers of heat transfer tube portions in different sections create inherent flow distribution patterns that automatically adapt to air flow variations, making the system self-regulating and eliminating the need for complex path count modifying means.

Inventive Principle:
Principle #25Self-service

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 enables fine adjustment of heat exchanging performance across the heat exchanger, enhancing efficiency by matching refrigerant flow distribution with air flow variations and reducing pressure losses, thus improving overall heat transfer efficiency.

Implementation Method 1

Air suctioned into a chassis of the air conditioner is subjected to a heat exchange with a refrigerant that flows through the refrigerant tubes while passing through gaps between the fins of the heat exchanger

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

Air suctioned into a chassis of the air conditioner is subjected to a heat exchange with a refrigerant that flows through the refrigerant tubes

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2535677B1Heat exchanger for air conditioner
Publication Date: 2015.04.01 DAIKIN INDUSTRIES LTD
  • EP2535677B1 patent drawingFigure 1
  • EP2535677B1 patent drawingFigure 2
  • EP2535677B1 patent drawingFigure 3

AI summary

A heat exchanger 71 comprises a plurality of refrigerant tubes R. In a flow divider 94, a part of a plurality of capillary tubes 96 is connected to an open end portion E1 on a side of a front tube plate 77, and a remainder of the plurality of the capillary tubes 96 is connected to an open end portion E1 on a side of a rear tube plate 79. The plurality of refrigerant tubes R include even number refrigerant tubes constituted by an even number of heat transfer tube portions P and odd number refrigerant tubes constituted by an odd number of heat transfer tube portions P.