Evaporator Header Layout for Equal Refrigerant Flow
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Solution Overview
Problem
Conventional evaporators for car air conditioners face challenges in maintaining equal refrigerant flow through heat exchange tubes, leading to increased passageway resistance and insufficient cooling performance, particularly due to uneven refrigerant distribution between tube groups forming a single path.
Innovation Solution
The evaporator design includes two tube rows with header portions that ensure equal channel sectional areas for refrigerant channels, using flow division members and communication passages to balance refrigerant flow between tube groups, and promoting members to enhance flow equality, thereby equalizing refrigerant distribution and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If communication means project from heat exchange core portion in lateral direction to connect leeward farthest section and windward farthest section, then refrigerant flow path is established, but dead space is produced when evaporator is installed
Solution Approach 1:
The communication passage connects the leeward farthest section and windward farthest section in the air-passage direction (front-rear dimension) rather than in the lateral direction. This dimensional change eliminates dead space while establishing the required refrigerant flow path between the two farthest sections.
2Reliability
If partition wall with communication holes is used to connect leeward farthest section and windward farthest section, then refrigerant communication is established, but refrigerant flow becomes uneven due to gravity influence
Solution Approach 1:
Flow division members are installed at specific locations within the leeward farthest section and windward farthest section to locally control and equalize refrigerant flow distribution. These members create balanced flow paths that compensate for gravitational effects, ensuring uniform refrigerant distribution to both tube groups.
3Reliability
If total channel sectional area of refrigerant channels decreases in heat exchange tubes, then passageway resistance increases, but cooling performance is reduced
Solution Approach 1:
The channel sectional area of refrigerant channels is optimized and maintained at appropriate levels throughout the heat exchange tubes, particularly in the path formed by the two farthest tube groups. This parameter optimization ensures low passageway resistance while maintaining effective cooling performance through balanced refrigerant flow distribution.
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 effectively enhances cooling performance by equalizing refrigerant flow through heat exchange tubes, reducing passageway resistance, and maintaining efficient evaporation, even in superheat regions, thus improving the overall performance of the evaporator.
Implementation Method 1
an evaporator which can equalize amounts of refrigerant flowing in heat exchange tubes
Implementation Method 2
maintaining efficient evaporation, even in superheat regions
Data Source
AI summary
A leeward tube row of an evaporator includes first to third tube groups, and a windward tube row thereof includes fourth and fifth tube groups. Within a third section of a leeward upper header portion with which heat exchange tubes of the third tube group communicate, a resistance member for flow division is provided so as to divide the interior of the third section into a first space which the heat exchange tubes face, and a second space which is separated from the first space and into which refrigerant flows. The resistance member for flow division has a plurality of refrigerant passage holes. The leeward upper header portion has a flow cutoff member for preventing flow of refrigerant into the first space of the third section. The third section of the leeward upper header portion communicates with the fourth section of the windward upper header portion via refrigerant communication passages.