Microchannel Heat Exchanger Manifold for Low Refrigerant Charge
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Solution Overview
Problem
Microchannel heat exchangers face limitations in refrigerant charge reduction due to their small internal volume, which is exacerbated by legislation restricting the use of low global warming potential refrigerants, and current designs struggle to efficiently distribute refrigerant while maintaining system efficiency.
Innovation Solution
The design incorporates a manifold with a reduced inner volume, featuring a distributor with increased wall thickness and a porous structure to optimize refrigerant distribution, allowing for a reduced refrigerant charge while maintaining efficient flow and heat transfer, including the use of asymmetrical and porous structures to enhance compactness and flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If microchannel heat exchangers use conventional manifold designs, then refrigerant distribution is maintained, but refrigerant charge cannot be sufficiently reduced
Solution Approach 1:
The patent employs a porous distributor structure within the manifold that allows refrigerant to distribute through porous walls into multiple channels. This porous material approach enables compact manifold design with reduced internal volume while maintaining effective refrigerant distribution, directly resolving the contradiction between reducing refrigerant charge and maintaining distribution performance
Solution Approach 2:
The distributor is positioned within the inner volume of the manifold, with portions arranged within the inlets of heat exchange tubes. This nested configuration allows the distributor to be contained within the manifold structure, maximizing space utilization and minimizing the manifold's external dimensions and refrigerant charge volume
2Quantity of substance
If manifold inner volume is reduced to lower refrigerant charge, then refrigerant charge is reduced, but refrigerant distribution efficiency deteriorates
Solution Approach 1:
The distributor features varying wall thicknesses in different regions, with thicker walls in areas requiring higher flow resistance and thinner walls where easier flow is needed. This local variation in quality allows the compact distributor to optimize refrigerant distribution across multiple channels despite reduced overall size, maintaining distribution efficiency while reducing charge
Solution Approach 2:
The patent utilizes changes in porosity parameters and wall thickness parameters of the distributor structure to control flow resistance and distribution patterns. By adjusting these parameters, the system achieves effective refrigerant distribution in a compact manifold with reduced internal volume
3Ease of manufacture
If distributor wall thickness is increased to improve structure, then manufacturing is simplified, but refrigerant charge reduction is limited
Solution Approach 1:
The distributor utilizes composite construction combining solid wall portions with porous sections. This composite approach allows the structure to maintain mechanical strength and ease of manufacture while the porous regions provide flow distribution functions, enabling compact design with reduced refrigerant charge
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 enables a significant reduction in refrigerant charge while maintaining or improving refrigerant distribution and heat exchanger efficiency, making it compatible with low global warming potential refrigerants and enhancing system compactness.
Implementation Method 1
a porous structure to optimize refrigerant distribution
Implementation Method 2
a porous structure to optimize refrigerant distribution
Implementation Method 3
heat exchanger tube arranged in spaced parallel relationship fluidly coupling the first and second manifolds
Implementation Method 4
heat exchanger for use in heat pump applications
Data Source
AI summary
A heat exchanger is provided including a first manifold, a second manifold separated from the first manifold, and a plurality of heat exchanger tubes arranged in spaced parallel relationship fluidly coupling the first and second manifolds. A first end of each heat exchange tube extends partially into an inner volume of the first manifold and has an inlet formed therein. A distributor is positioned within the inner volume of the first manifold. At least a portion of the distributor is arranged within the inlet formed in the first end of one or more of the plurality of heat exchange tubes.