Heat exchanger and air-conditioning apparatus
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Solution Overview
Problem
Heat exchangers with flat tubes face challenges in evenly distributing refrigerant due to increased pressure loss, especially when using a communication header as a distributor, leading to performance deterioration, and the use of a stack type distributor restricts design flexibility due to fixed increments of refrigerant streams.
Innovation Solution
A heat exchanger design incorporating a combination of distributors with collision walls and a communication header that branches refrigerant into a smaller number of streams, allowing for even distribution and optimizing the number of rows for maximum performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of refrigerant streams is increased to reduce pressure loss, then pressure loss is reduced, but refrigerant distribution becomes uneven
Solution Approach 1:
The refrigerant distributor is divided into multiple independent distributors, each handling a subset of heat transfer pipes. This segmentation allows each distributor to manage refrigerant flow to a specific group of pipes, ensuring uniform distribution within each group while collectively serving all pipes. The segmentation prevents the refrigerant flow imbalance that occurs when a single distributor serves all pipes with high stream count.
Solution Approach 2:
Independent distributors act as intermediary components between the refrigerant source and the heat transfer pipes. Each distributor independently controls and distributes refrigerant to its assigned pipes, mediating the flow to ensure uniformity. This intermediary structure prevents the direct connection problems that cause uneven distribution in single-distributor systems with high stream counts.
2Manufacturing precision
If a stack type distributor is used to achieve even refrigerant distribution, then refrigerant distribution uniformity is improved, but design flexibility is reduced
Solution Approach 1:
The system uses multiple independent distributors instead of a single stack type distributor. Each distributor can be independently designed and configured based on the specific requirements of the heat transfer pipes it serves. This segmentation allows for greater design flexibility, as each distributor unit can be optimized independently rather than being constrained by the fixed structure of a single stack type distributor.
Solution Approach 2:
The system allows for dynamic configuration by using multiple independent distributors that can be arranged and configured flexibly according to different design requirements. Unlike the fixed increment structure of stack type distributors, this approach enables adaptive design where the number and arrangement of distributors can be adjusted to match various heat exchanger configurations and performance targets.
3Productivity
If flat tubes are used to reduce refrigerant amount and increase performance, then heat exchanger performance is improved, but refrigerant distribution becomes uneven
Solution Approach 1:
The use of multiple independent distributors compensates for the challenges of distributing refrigerant to flat tube heat exchangers. Each distributor independently manages refrigerant flow to a subset of flat tubes, ensuring uniform distribution despite the small hydraulic diameter of flat tubes that makes them sensitive to flow distribution issues.
Solution Approach 2:
Independent distributors serve as intermediary components that carefully control refrigerant distribution to flat tubes. This intermediary structure prevents the uneven flow that would otherwise occur due to the small hydraulic diameter of flat tubes, ensuring that each tube receives appropriate refrigerant flow while maintaining high heat exchanger performance.
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 solution enables even refrigerant distribution and maximizes heat exchanger performance by using distributors with collision walls and a communication header that branches refrigerant into a smaller number of streams, overcoming the limitations of fixed increments and improving thermal efficiency.
Implementation Method 1
one or more distributors each including a collision wall therein, and being configured to cause the refrigerant that flows from the first inlet into the one or more distributors to branch into refrigerant streams because of collision of the refrigerant with the collision wall
Implementation Method 2
a heat exchange module including a plurality of fins and a plurality of heat transfer pipes, and configured to cause heat exchange to be performed between refrigerant that flows in the heat exchange module and air that flows around the heat exchange module
Implementation Method 3
the plurality of fins being arranged apart from each other in a first direction, the heat transfer pipes being provided to extend through the plurality of fins and arranged apart from each other in a second direction crossing the first direction
Data Source
AI summary
A heat exchanger includes: a heat exchange module including fins and heat transfer pipes; and a refrigerant distributor connected to an end portion of the heat exchange module. The refrigerant distributor includes: one or more distributors including a first inlet and first outlets, and configured to cause the refrigerant that flows from the first inlet into the one or more distributors to branch into refrigerant streams, and cause each of the refrigerant streams to flow out from an associated one of the first outlets; and a communication header including a second inlet and second outlets with which some others of the heat transfer pipes are connected, and configured to cause the refrigerant that flows from the second inlet to branch into refrigerant streams, and cause each of the refrigerant streams to flow out from an associated one of the second outlets.