Heat Exchanger Header Loop Structure for Uniform Refrigerant Flow

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Solution Overview

Problem

Existing heat exchangers face challenges in maintaining efficient refrigerant flow and preventing eccentric flow at varying circulation rates, as throttles either fail to ensure adequate flow at low rates or cause excessive accumulation at high rates, leading to inefficiencies in heat exchange.

Innovation Solution

The heat exchanger incorporates a loop structure with partition members and communicating passages to manage refrigerant flow, allowing it to ascend and descend within the header collecting tube, ensuring consistent flow even at varying circulation rates by guiding refrigerant through specific passages and ports, thereby preventing eccentric flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a throttle is formed in the header collecting tube to raise flow velocity and suppress eccentric flow at low circulation rates, then refrigerant can reach the top ends effectively, but at high circulation rates the flow velocity becomes too high causing excessive refrigerant accumulation at the top and eccentric flow

Engineering Contradiction:
Improverefrigerant flow velocityVSAvoideccentric flow suppression
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The header collecting tube is divided into multiple segments by partition members, creating separate flow regions (first space for ascent, second space for descent). This segmentation allows different flow control mechanisms to operate in different regions, enabling the system to handle both low and high circulation rates effectively without a single throttle causing problems at both extremes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow control mechanism is made dynamic through the loop structure with communicating passages that allow refrigerant to circulate in different patterns. At low circulation rates, the throttle raises velocity; at high circulation rates, the loop structure provides alternative flow paths that prevent excessive velocity and accumulation, adapting to varying operating conditions.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the refrigerant circulation rate is low, then a throttle can raise flow velocity to reach top ends, but if the circulation rate is high, the throttle causes excessive flow velocity and refrigerant accumulation at the top

Engineering Contradiction:
Improverefrigerant circulation efficiencyVSAvoidflow distribution uniformity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The loop structure creates a feedback mechanism where refrigerant that accumulates at the top can be redirected back through the communicating passages to lower regions. This feedback loop prevents excessive accumulation by automatically redirecting surplus refrigerant, maintaining uniform flow distribution across different circulation rates.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes flow parameters dynamically through the loop structure. At low circulation rates, the throttle increases velocity; at high circulation rates, the loop structure modifies the flow path and velocity distribution, effectively changing the operational parameters to maintain reliability across varying conditions.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If partition members are added to create ascending and descending flow spaces, then refrigerant flow can be controlled at varying circulation rates, but the device structure becomes more complex

Engineering Contradiction:
Improvecirculation rate adaptabilityVSAvoidheader collecting tube structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The partition members and communicating passages serve multiple functions: they create flow separation for velocity control, establish loop structures for circulation management, and provide adaptive flow paths for different circulation rates. This multi-functionality reduces the need for separate components for each function, offsetting the added structural complexity with functional consolidation.

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 ensures efficient refrigerant flow to the flat tubes at both low and high circulation rates, minimizing eccentric flow and maintaining effective heat exchange performance across different operational conditions.

Implementation Method 1

The first partition member partitions internal space of the header collecting tube into upper internal space and lower internal space. The second partition member partitions the upper internal space into first space, which is space for making the refrigerant ascend, and second space, which is space for making the refrigerant descend

Methodology Applied
Scientific EffectGravitational convection: Gravitational Convection (non heat)

Implementation Method 2

The upper communicating passage is located in upper part of the first space and the second space, and provide communication between the upper part of the first space and the second space. The lower communicating passage, which is located in lower part of the first space and the second space, provide communication between the lower part of the first space and the second space

Methodology Applied
Scientific EffectPressure gradient flow: Pressure Gradient

Data Source

PatentEP3088832B1Heat exchanger and air conditioning device
Publication Date: 2018.04.25 DAIKIN INDUSTRIES LTD
  • EP3088832B1 patent drawingFigure 1
  • EP3088832B1 patent drawingFigure 2
  • EP3088832B1 patent drawingFigure 3

AI summary

Provided are a heat exchanger and an air conditioning device, with which it is possible to form an ascending flow of refrigerant even in a structure in which refrigerant is not directly supplied to the part of lower space in a header collecting tube where a refrigerant ascending flow is created. A plurality of flat multi-perforated tubes (21b) are connected at different heightwise locations to a first internal space (23a) of a doubled-back header collecting tube (23) of an outdoor heat exchanger (20). For the first internal space (23a), a loop structure is adopted including a first partition plate (51), first inflow port (41x) for causing refrigerant to ascend within a first outflow space (51a), and a first lower communicating passage (51y) for causing the refrigerant from a first upper communicating passage (51x) to descend in a first loop space (51b) and guiding the refrigerant back to the first outflow space (51 a). The flat multi-perforated tubes (21b) are connected at one end to either the first outflow space (51a) or the first loop space (51b). An interconnecting pipeline (24) is connected to a space that, within a first flow regulation plate (41), is underneath the first loop space (51b).