Outdoor Heat Exchanger Header Partition for Uniform Refrigerant Flow
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Solution Overview
Problem
In heat exchangers with flat tubes, the density difference between liquid and gas refrigerants leads to accumulation of liquid refrigerant at the bottom of communication spaces, resulting in reduced wetness and inefficient performance, particularly when the refrigerant flows into upper tubes, where it may turn into a single-phase gas, rendering those regions ineffective as evaporators.
Innovation Solution
The introduction of a vertical partition plate in the communication spaces divides the flow path into two sections, increasing the refrigerant flow rate by reducing the cross-sectional area, ensuring the gas-liquid two-phase refrigerant is distributed uniformly across the flat tubes, thereby maintaining consistent wetness and enhancing performance without complex design modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flat tubes are inserted deep inside the communication space to reduce the cross-sectional area of the refrigerant flow path, then the flow rate of the refrigerant is increased, but the header collecting pipe requires significant design modification to adjust the flow rate to an optimum level
Solution Approach 1:
The communication space is divided into an upstream communication space and a downstream communication space by introducing a partition plate. This segmentation allows the upstream space to be optimized for increasing refrigerant flow rate by reducing its cross-sectional area, while the downstream space maintains the necessary flow path to the flat tubes. The partition plate creates distinct functional zones that can be independently optimized, resolving the contradiction between increasing flow rate and maintaining simple design.
2Productivity
If the cross-sectional area of the refrigerant flow path is reduced to increase the flow rate, then the refrigerant flows faster, but it becomes difficult to easily adjust the flow rate to an optimum level
Solution Approach 1:
The partition plate is designed to be movable or adjustable within the header collecting pipe, allowing the cross-sectional area of the upstream communication space to be dynamically modified. This enables easy adjustment of the refrigerant flow rate to an optimum level by changing the position or configuration of the partition plate, rather than requiring significant design modifications. The dynamic element provides adaptability while maintaining the flow rate increase benefit.
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 solution significantly increases the refrigerant flow rate and ensures uniform distribution, reducing variations in wetness across the flat tubes, thereby improving the heat exchanger's performance and allowing it to function effectively as an evaporator.
Implementation Method 1
the partition plate (91) which extends in the vertical direction and divides the upstream communication space (75a-75f) into a first space (93) that communicates with the plurality of flat tubes (31) and a second space (94) that communicates with an inlet portion configured to introduce a refrigerant into the upstream communication space (75a-75f)
Implementation Method 2
the density of the liquid refrigerant is greater than the density of the gas refrigerant. Thus, if the refrigerant flows at a slow rate in the communication space, it is likely that the liquid refrigerant accumulates at the bottom of the communication space due to the gravity
Implementation Method 3
configured to exchange heat between a refrigerant and air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is an outdoor heat exchanger in which a first principal communication space (75a) that communicates with an upstream side of a plurality of flat tubes (31) when the outdoor heat exchanger functions as an evaporator is provided with a partition plate (91). The partition plate (91) extends in a vertical direction, and divides the first principal communication space (75a) into a first space (93) which communicates with the plurality of flat tubes (31), and a second space (94) which communicates with a branch pipe portion (112a) for introducing a refrigerant into the first principal communication space (75a) when the outdoor heat exchanger functions as an evaporator. A through hole (91a) allowing the first space (93) and the second space (94) to communicate with each other is formed at a lower portion of the first principal communication space (75a).