Heat Exchanger Segmented Flow Path Design for Faster Defrosting
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Solution Overview
Problem
In air conditioners, frost accumulation on outdoor heat exchangers during heating operations leads to slower defrosting due to reduced refrigerant flow rates in lowermost heat transfer tubes, prolonging the defrosting process.
Innovation Solution
A heat exchanger design with multiple heat transfer tubes aligned vertically, featuring separate flow paths in the liquid header to enhance refrigerant flow rates, including a first flow path for the lowermost tube and a second flow path for upper tubes, preventing refrigerant obstruction and improving defrosting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid refrigerant flows through a single common flow path in the liquid header, then the structure is simple, but the refrigerant flow rate through the lowermost heat transfer tube is reduced due to accumulation, slowing down defrosting speed
Solution Approach 1:
The liquid header is segmented into multiple flow paths (first flow path for lowermost tube, second flow path for upper tubes) to prevent refrigerant accumulation and ensure adequate flow rate to all heat transfer tubes, thereby improving defrosting speed without excessive complexity
Solution Approach 2:
Different flow paths are provided for different locations (lowermost vs. upper tubes) based on their specific needs, with the lowermost tube receiving dedicated flow path attention to ensure sufficient refrigerant supply for effective defrosting
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 ensures a higher refrigerant flow rate through the lowermost heat transfer tube, accelerating the defrosting process and improving overall defrosting capability.
Implementation Method 1
the liquid header includes a first flow path to which the first connection tube and the first heat transfer tube are connected, and a second flow path to which the second connection tube and the second heat transfer tube are connected
Implementation Method 2
a plurality of heat transfer tubes aligned in an up-down direction... when the heat exchanger is used as a condenser for defrosting operation
Implementation Method 3
the liquid refrigerant flowing from the first heat transfer tube into the liquid header is discharged from the first connection tube to outside of the heat exchanger through the first flow path
Data Source
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AI summary
A heat exchanger (14) includes a plurality of heat transfer tubes (26) aligned in an up-down direction, a liquid header (21) to which ends of the plurality of heat transfer tubes (26) are connected, and a plurality of connection tubes (35) aligned in the up-down direction and connected to the liquid header (21), in which the plurality of heat transfer tubes (26) include a first heat transfer tube (26a) disposed at a lowermost position and a second heat transfer tube (26b) disposed above and adjacent to the first heat transfer tube (26a), the plurality of connection tubes (35) include a first connection tube (35A) disposed at a lowermost position and a second connection tube (35B) disposed above the first connection tube (35A), and the liquid header (21) includes a first flow path (33A) to which the first connection tube (35A) and the first heat transfer tube (26a) are connected, and a second flow path (33B) to which the second connection tube (35B) and the second heat transfer tube (26b) are connected.