Heat exchanger and air conditioning device

Solution Overview

Problem

Heat exchangers with flat tubes and headers face challenges in minimizing eccentric flow of refrigerant, which occurs due to varying circulation rates, with existing solutions either failing to control flow velocity effectively at low or high circulation rates.

Innovation Solution

A heat exchanger design featuring a loop structure within the header collecting tube, including partition members, inflow ports, upper and lower communicating passages, which guides the refrigerant to ascend and descend through narrow spaces, ensuring even distribution and minimizing eccentric flow at both low and high circulation rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a throttle is formed inside the header collecting tube to increase flow velocity, then eccentric flow is minimized at low circulation rates, but flow velocity becomes too high at high circulation rates causing liquid phase refrigerant to collect excessively towards the top

Engineering Contradiction:

Improveminimization of eccentric flowVSAvoidperformance under varying circulation rates

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The header collecting tube is divided into multiple sections with different throttle openings. The internal space is segmented into a first space with a first throttle opening and a second space with a second throttle opening, allowing different flow control in different sections to adapt to varying circulation rates and prevent eccentric flow under all operating conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the header collecting tube are given different throttle characteristics. The first throttle opening and second throttle opening have different opening degrees, creating local variations in flow resistance that optimize refrigerant distribution across different circulation rate scenarios.

Inventive Principle:

Principle #3Local quality

2Speed

If the throttle is adjusted to minimize eccentric flow at high circulation rates, then flow velocity is controlled, but at low circulation rates it becomes difficult for the refrigerant to reach the top giving rise to eccentric flow

Engineering Contradiction:

Improveflow velocity controlVSAvoideccentric flow prevention

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The header collecting tube is divided into multiple sections with different throttle openings. The internal space is segmented into a first space with a first throttle opening and a second space with a second throttle opening, allowing different flow control in different sections to adapt to varying circulation rates and prevent eccentric flow under all operating conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the header collecting tube are given different throttle characteristics. The first throttle opening and second throttle opening have different opening degrees, creating local variations in flow resistance that optimize refrigerant distribution across different circulation rate scenarios.

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

The design effectively maintains even refrigerant flow to flat tubes at different heights, minimizing eccentric flow and ensuring sufficient refrigerant distribution across varying circulation rates, thereby enhancing heat exchange efficiency.

Implementation Method 1

liquid phase refrigerant of high specific gravity collects towards the bottom while gas phase refrigerant of low specific gravity collects towards the top, thereby giving rise to eccentric flow

Methodology Applied

Scientific EffectGravitational separation: Gravitation

Implementation Method 2

liquid phase refrigerant of high specific gravity collects towards the bottom while gas phase refrigerant of low specific gravity collects towards the top

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 3

The inflow ports are located in lower parts of the first spaces, and in the case of functioning as a refrigerant evaporator, prompt inflow of refrigerant so as to give rise to an ascending flow within the first spaces

Methodology Applied

Scientific EffectGravitational convection: Gravitational Convection (non heat)

Data Source

PatentUS10655917B2Heat exchanger and air conditioning device

Publication Date: 2020.05.19 DAIKIN INDUSTRIES LTD

AI summary

A heat exchanger for an air conditioning device includes flat tubes, a vertically extending header collecting tube connected to the flat tubes, and fins joined to the flat tubes. The header collection tube has a loop structure including partition members, inflow ports, and upper and lower communicating passages. The partition members partition first and second spaces. The flat tubes are connected at the first spaces. The inflow ports are located in lower parts of the first spaces. The upper communicating passages communicate the upper parts of the first and second spaces to guide refrigerant from the first spaces into the second spaces. The lower communicating passages communicate the lower parts of the first and second spaces to guide refrigerant from the second spaces towards spaces above the inflow ports in the first spaces to return the refrigerant from the second spaces to the first spaces.