Heat Exchanger Header Bypass Layout for Low Pressure Loss
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Solution Overview
Problem
Existing heat exchangers face increased pressure loss and lubricating oil stagnation issues when operating as evaporators, which affects their defrosting performance and efficiency.
Innovation Solution
Incorporating a first bypass pipe that communicates with the header and refrigerant pipe at specific positions to optimize refrigerant flow, reducing pressure loss and facilitating the recirculation of lubricating oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat transfer tubes communicate with the header at side portions to improve defrosting performance, then defrosting performance is improved, but pressure loss increases and lubricating oil stagnates
Solution Approach 1:
The header's internal space is segmented into an upper space and a lower space by a partition wall. The partition wall has a through-hole that allows refrigerant to flow between spaces. This segmentation enables different refrigerant flow paths for different operations: during defrosting, refrigerant can be directed to lower portions; during normal operation, refrigerant flows efficiently through the upper space, reducing pressure loss and preventing oil stagnation.
2Reliability
If heat transfer tubes communicate with the header at side portions to improve defrosting performance, then defrosting performance is improved, but lubricating oil stagnation occurs
Solution Approach 1:
The header's internal space is segmented into an upper space and a lower space by a partition wall. The partition wall has a through-hole that allows refrigerant to flow between spaces. This segmentation enables different refrigerant flow paths for different operations: during defrosting, refrigerant can be directed to lower portions; during normal operation, refrigerant flows efficiently through the upper space, reducing pressure loss and preventing oil stagnation.
Solution Approach 2:
Different regions of the header are given different functions through the partition wall. The upper space is optimized for normal refrigerant flow with reduced pressure loss, while the lower space is optimized for defrosting operations. The through-hole in the partition wall allows selective access between regions, enabling each region to perform its specialized function without compromising the other.
3Productivity
If multiple heat transfer tubes are arranged vertically to increase heat exchange capacity, then heat exchange capacity is improved, but pressure loss and oil stagnation increase
Solution Approach 1:
The header's internal space is segmented into an upper space and a lower space by a partition wall. The partition wall has a through-hole that allows refrigerant to flow between spaces. This segmentation enables different refrigerant flow paths for different operations: during defrosting, refrigerant can be directed to lower portions; during normal operation, refrigerant flows efficiently through the upper space, reducing pressure loss and preventing oil stagnation.
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
The solution enhances defrosting performance, reduces pressure loss, and minimizes lubricating oil stagnation, improving the overall efficiency and manufacturing ease of the heat exchanger.
Implementation Method 1
a first bypass pipe having ends one of which communicates with a lower portion of the header and the other of which communicates with a middle portion of the refrigerant pipe
Implementation Method 2
optimize refrigerant flow, reducing pressure loss and facilitating the recirculation of lubricating oil
Data Source
Figure 1
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Figure 4~5
AI summary
A heat exchanger includes a plurality of heat transfer tubes arranged at predetermined intervals in a vertical direction, a tubular header that has a plurality of connection portions where the heat transfer tubes are connected to a side portion of the header and that communicates with each of the heat transfer tubes, a refrigerant pipe that communicates with the header at a middle portion of the header in the vertical direction, and a first bypass pipe having ends one of which communicates with a lower portion of the header and the other of which communicates with a middle portion of the refrigerant pipe. A distance between a communication position at which the first bypass pipe and the refrigerant pipe communicate with each other and an inner wall of the header is not more than double an inside diameter of the refrigerant pipe.