Segmented Flat-Tube Heat Exchanger for Reversible Refrigerant Flow
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Solution Overview
Problem
Conventional heat exchangers with a double-column structure face performance issues as an evaporator and condenser due to the varying refrigerant flow path, particularly when the refrigerant flows from the windward to the leeward tube bank, leading to inadequate heat exchange efficiency.
Innovation Solution
A heat exchanger design with a windward and leeward tube bank divided into principal and auxiliary sections, where the refrigerant flows from the auxiliary to the principal sections in the evaporator mode and vice versa in the condenser mode, ensuring uniform wetness and mass flow rate across the tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the refrigerant flows from the windward tube bank to the leeward tube bank in a conventional double-column heat exchanger, then the refrigerant distribution is simplified, but the heat exchange efficiency deteriorates due to non-uniform wetness and inadequate temperature difference utilization
Solution Approach 1:
The windward tube bank is divided into a first windward tube bank and a second windward tube bank, creating separate flow paths. This segmentation allows the refrigerant to flow through different tube banks in sequence, improving heat exchange efficiency by maintaining uniform wetness and adequate temperature difference across all tubes, thereby resolving the contradiction between simplified flow path configuration and heat exchange efficiency
Solution Approach 2:
The invention reverses the conventional single-direction flow by implementing a U-shaped flow path where the refrigerant flows from the first windward tube bank to the leeward tube bank and then returns to the second windward tube bank. This inversion creates a more efficient heat exchange process by ensuring uniform refrigerant distribution and maintaining temperature difference across all tube banks, thus improving heat exchange efficiency without significantly increasing flow path complexity
2Productivity
If the refrigerant flow path is extended to improve heat exchange efficiency, then the temperature difference utilization improves, but the pressure loss increases
Solution Approach 1:
The extended flow path is segmented into distinct sections (first windward tube bank, leeward tube bank, second windward tube bank) with organized connections. This segmentation allows the refrigerant to flow through multiple tube banks in a controlled manner, maximizing heat exchange efficiency while managing pressure loss through structured flow distribution and collection
Solution Approach 2:
Header tubes serve as intermediaries connecting the different tube banks. The header tubes collect refrigerant from one tube bank and distribute it to the next, facilitating the extended flow path while minimizing pressure loss through efficient fluid collection and redistribution, thus enabling extended flow path for improved heat exchange efficiency without excessive pressure loss
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 enhances the heat exchange efficiency by maintaining a lower temperature in evaporator mode and a higher temperature in condenser mode, ensuring both modes operate effectively, with improved refrigerant distribution and reduced wetness differences across the tubes.
Implementation Method 1
a heat exchanger configured to exchange heat between a refrigerant flowing through a plurality of flat tubes (31, 61) and air
Implementation Method 2
If a gas-liquid two-phase refrigerant flows into flat tubes (501) with uniform wetness
Data Source
Figure 1
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AI summary
In a heat exchanger (23), a principal windward heat exchange region (35) includes a principal windward bank portion, a principal leeward heat exchange region (65) includes a principal leeward bank portion, an auxiliary windward heat exchange region (37) includes an auxiliary windward bank portion, and an auxiliary leeward heat exchange region (67) includes an auxiliary leeward bank portion. Each of the principal and auxiliary bank portions is constituted of a plurality of flat tubes. In the heat exchanger (23) functioning as an evaporator, a refrigerant flows sequentially through the auxiliary windward, auxiliary leeward, principal leeward, and principal windward bank portions. In the heat exchanger (23) functioning as a condenser, a refrigerant flows sequentially through the principal windward, principal leeward, auxiliary leeward, and auxiliary windward bank portions. Consequently, the heat exchanger exhibits performance sufficient for functioning as both an evaporator and a condenser.