Heat exchanger unit
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Solution Overview
Problem
The existing two-row-configuration heat exchanger with flat multi-hole pipes used in air-conditioning apparatuses faces challenges in maintaining a sufficient temperature difference between air and refrigerant, particularly at the subcooling region, leading to suppressed heat-exchanging performance.
Innovation Solution
The heat exchanger unit is configured with a first heat exchanger on the air upstream side and a second heat exchanger on the air downstream side, featuring a fourth header that directs refrigerant flow from the second heat exchanger to the first heat exchanger, creating a subcooling region on the upstream side, thereby increasing the temperature difference and the amount of refrigerant subcooled, and optimizing the refrigerant flow direction to reduce temperature irregularity and heat conduction loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the circulation direction of refrigerant is opposite between the first heat exchanger on air upstream side and the second heat exchanger on air downstream side, then the heat exchanger unit can be configured as a two-row-configuration system, but the temperature difference between air and refrigerant is not easily assured at the subcooling region of the second heat exchanger, suppressing heat-exchanging performance
Solution Approach 1:
The patent inverts the conventional opposite-flow configuration by making the refrigerant flow in the same direction through both heat exchangers. Specifically, the fourth header causes refrigerant to flow from the second heat exchanger back to the first heat exchanger, creating a unified flow path that maintains temperature difference across both units and enables effective subcooling in the second heat exchanger.
2Temperature
If air is heated by passing through the superheating region of the heat exchanger on the air upstream side, then the air can be prepared for downstream flow, but the heated air flows into the heat exchanger on the air downstream side where temperature difference is not easily assured, suppressing refrigerant subcooling
Solution Approach 1:
The patent changes the refrigerant flow direction parameter to flow from the second heat exchanger back to the first heat exchanger through the fourth header. This parameter change allows the system to maintain adequate temperature difference in the second heat exchanger despite receiving heated air from the first heat exchanger, thereby increasing the refrigerant subcooling amount and improving heat-exchanging performance.
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 enhances the heat-exchanging performance of the air-conditioning apparatus by increasing the refrigerant subcooling amount, reducing temperature irregularity, and improving the evaporator performance by eliminating the need for intermediate pipes, resulting in improved efficiency and reduced pressure loss.
Implementation Method 1
a first heat exchanger (52) provided on an air upstream side, and a second heat exchanger (62) provided on an air downstream side
Implementation Method 2
a refrigerant that flows in the second heat exchanger (62) on the air downstream side can be subcooled at a first heat exchanging region, on the air upstream side
Data Source
AI summary
A heat exchanger unit includes: a first heat exchanger including a first header, a second header, and a first flat pipe group that includes first flat multi-hole pipes connected to each of the first header and the second header; and a second heat exchanger: disposed in parallel with the first heat exchanger on an air downstream side, from the first heat exchanger, of air flow generated by a fan; and including a third header, a fourth header, and a second flat pipe group that includes second flat multi-hole pipes connected to each of the third header and the fourth header. The fourth header causes a refrigerant that flows in from the third header to flow out to the first header.