Heat exchanger and air conditioner
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In heat exchangers used as evaporators, the separation of gas and liquid refrigerants leads to refrigerant drift, reducing performance due to uneven distribution and increased wetness ratios, especially in downstream regions where superheated gas refrigerant flows, impairing heat exchange efficiency.
Innovation Solution
The heat exchanger is configured with a series connection of heat exchange regions, where the downstream region has more heat exchange sections than the upstream region, reducing the height of communicating spaces and minimizing refrigerant separation by increasing the number of communicating spaces and decreasing the number of flat tubes per space, and using branch pipes to distribute refrigerant evenly across sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refrigerant is distributed from the communicating space into the plurality of vertically arranged flat tubes, then the refrigerant exchanges heat with the air, but the gas and liquid refrigerants are separated by gravity causing drift and reducing heat exchange efficiency
Solution Approach 1:
The heat exchanger is divided into multiple heat exchange regions (first region with first number of flat tubes, second region with second number of flat tubes) where the numbers are different. This segmentation creates different refrigerant distribution patterns in each region, preventing uniform drift and improving overall heat exchange efficiency by maintaining better liquid-gas mixture distribution.
2Productivity
If the downstream principal heat exchange region has more heat exchange sections, then the refrigerant distribution should be improved, but the drift occurs more easily due to higher gas refrigerant ratio
Solution Approach 1:
Different heat exchange regions are designed with different numbers of flat tubes to create local variations in refrigerant distribution characteristics. The first heat exchange region has a different number of flat tubes compared to the second region, allowing each region to have optimized local properties that prevent drift while maintaining good evaporator performance.
3Stability of the object's composition
If the number of flat tubes per communicating space is reduced, then the communicating space height decreases reducing drift, but the number of communicating spaces must increase affecting device complexity
Solution Approach 1:
The heat exchanger is segmented into multiple regions with different numbers of flat tubes per communicating space. This segmentation allows the system to reduce the number of flat tubes in certain regions to decrease communicating space height and prevent drift, while the overall structure remains manageable through the segmented design approach.
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 reduces refrigerant drift and enhances performance by ensuring even distribution and heat exchange, maintaining efficiency even with small refrigerant amounts and varying section sizes, allowing the heat exchanger to function effectively as an evaporator.
Implementation Method 1
the heat exchanger allowing a refrigerant flowing through the flat tubes (31) and air to exchange heat
Implementation Method 2
fins (32) joined to the flat tubes (31)
Implementation Method 3
the refrigerant distributed into the plurality of flat tubes exchanges heat with the air to evaporate
Implementation Method 4
the gas and liquid refrigerants are separated from each other by gravity, and thus a drift of the refrigerant tends to occur
Implementation Method 5
The refrigerant distributed into the plurality of flat tubes exchanges heat with the air to evaporate
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In two heat exchange regions (35, 37) connected together in series when an outdoor heat exchanger (23) functions as an evaporator, a downstream one (35) of the heat exchange regions has heat exchange sections not less than heat exchange sections of an upstream one (37) of the heat exchange regions, and a most downstream one (35) of the heat exchange regions has more heat exchange sections than a most upstream one (37) of the heat exchange regions.