Segmented Air Conditioner Heat Exchanger for Uniform Subcooling

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Solution Overview

Problem

Air-conditioning apparatuses with a single air outlet suffer from reduced heat exchange efficiency due to variations in air flow speeds across different regions, leading to uneven subcooling and heat exchange performance.

Innovation Solution

The design includes a housing with intake and blowout air passages, a fan that blows air in a circumferential direction, and strategically positioned heat exchangers such as a front, rear, and side heat exchangers, with the second heat exchanger located downstream to efficiently subcool refrigerant and reduce pressure losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single air outlet is provided in the housing, then the structure is simplified, but the heat exchange efficiency is reduced due to non-uniform air flow distribution

Engineering Contradiction:
ImprovestructureVSAvoidheat exchange efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The housing is divided into multiple air outlets (first air outlet and second air outlet) positioned at different locations, and the heat exchanger is segmented into multiple sections (first heat exchanger and second heat exchanger) corresponding to each outlet. This segmentation allows air flow to be distributed more uniformly across different regions, with each outlet serving a specific heat exchanger section, thereby maintaining heat exchange efficiency while keeping the structure relatively simple.

Inventive Principle:
Principle #1Segmentation

2Productivity

If heat exchangers are disposed around the fan to improve heat exchange efficiency, then the heat exchange efficiency is improved, but the air flow speed variation between different regions increases

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidair flow speed uniformity
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

Different sections of the heat exchanger are positioned at different locations around the fan (front, rear, and side positions), and corresponding air outlets are provided at different locations on the housing. This local quality approach ensures that each heat exchanger section receives air flow appropriate to its position, with air outlets strategically placed to maintain relatively uniform air flow speeds across different regions, thereby resolving the contradiction between heat exchange efficiency and air flow uniformity.

Inventive Principle:
Principle #3Local quality

3Device complexity

If air outlets are not provided symmetrically with respect to the fan, then the housing structure is simplified, but the subcooling uniformity is reduced

Engineering Contradiction:
Improvehousing structureVSAvoidsubcooling uniformity
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The air outlets are intentionally positioned asymmetrically with respect to the fan, with the first air outlet and second air outlet located at different positions on the housing. Correspondingly, the heat exchanger sections are arranged to match this asymmetric configuration. This asymmetric design simplifies the housing structure while maintaining subcooling uniformity by ensuring that each heat exchanger section is properly positioned to receive and process air flow according to its specific location.

Inventive Principle:
Principle #4Asymmetry

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 efficiency by ensuring uniform air flow and reduced pressure losses, improving the overall performance of the air-conditioning system even when the air outlet is not symmetrically positioned relative to the fan.

Implementation Method 1

The fan blows air that is sucked into the fan from the air inlet and the intake air passage, in a circumferential direction, which is perpendicular to a direction in which the air is sucked into the fan

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

When the front heat exchanger operates as a condenser, the first heat exchanger operates as a condenser, and in the second heat exchanger, condensed and liquified refrigerant flows

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the first heat exchanger and the second heat exchanger, which are arranged in such a manner as to face the air outlet

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3726151B1Air conditioner
Publication Date: 2023.08.23 MITSUBISHI ELECTRIC CORP
  • EP3726151B1 patent drawingFigure 1~2
  • EP3726151B1 patent drawingFigure 3~4
  • EP3726151B1 patent drawingFigure 5~6

AI summary

An air-conditioning apparatus includes: a housing having an intake air passage communicating with an air inlet and a blowout air passage communicating with an air outlet that allows air to be blown out in a single direction; a fan; a front heat exchanger facing the air outlet of the housing; and at least one of rear and side heat exchangers that face rear and side surfaces of the housing, respectively. The fan blows out air sucked thereinto from the air inlet and the intake air passage, in a circumferential direction perpendicular to a direction in which the air is sucked into the fan, from the air outlet through the blowout air passage. The front heat exchanger includes first and second heat exchangers. When the front heat exchanger operates as a condenser, the first heat exchanger operates as a condenser, and in the second heat exchanger, condensed and liquified refrigerant flows. When the front heat exchanger and the at least one of the rear and side heat exchangers operate as condensers, the second heat exchanger is located downstream of the first heat exchanger and the at least one of the rear and side heat exchangers in the flow direction of refrigerant.