Evaporator Refrigerant Path Layout for Downstream Row Heat Exchange
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Solution Overview
Problem
In air conditioning heat exchangers, heat transfer tubes arranged in multiple rows experience reduced efficiency in downstream rows due to rising refrigerant temperature and uneven airflow velocities, leading to inadequate cooling capacity.
Innovation Solution
The heat exchanger configuration includes a most downstream path composed solely of heat transfer tubes in the most downstream row, with the upstream paths made up of tubes in multiple rows on the upstream side, ensuring efficient heat exchange by maintaining refrigerant superheat and aligning the most downstream path with areas of low airflow velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat transfer tubes are arranged in multiple rows in the airflow direction with refrigerant flowing sequentially from upstream to downstream, then the heat exchange is mostly performed in the upstream rows, but the heat exchange efficiency in downstream rows deteriorates due to rising refrigerant temperature
Solution Approach 1:
The refrigerant flow path is segmented into multiple independent paths (first path, second path, third path) that are arranged in parallel. Each path contains heat transfer tubes distributed across different rows (first row, second row, third row). This segmentation allows different portions of the refrigerant to flow through different row combinations simultaneously, ensuring that downstream rows receive cooler refrigerant from paths that haven't traversed as many rows, thereby maintaining heat exchange efficiency in downstream positions.
Solution Approach 2:
The invention transitions from a single-dimensional sequential flow (one path through all rows) to a multi-dimensional parallel flow structure. Multiple refrigerant paths are arranged in the vertical direction (height direction) while also distributing tubes across the airflow direction (horizontal rows). This dimensional expansion allows refrigerant to access downstream rows through shorter path lengths in certain paths, maintaining temperature differential and heat exchange effectiveness.
2Area of stationary object
If heat transfer tubes are arranged in multiple rows, then more heat transfer area is provided, but the downstream rows are not used effectively due to uneven airflow velocity and high refrigerant temperature
Solution Approach 1:
The heat transfer tube arrangement is segmented into multiple paths where each path selectively utilizes tubes from different rows. The first path uses tubes from the first row, the second path uses tubes from the second row, and the third path uses tubes from the third row. This segmentation ensures that downstream rows (second and third rows) are actively utilized by dedicated paths that introduce cooler refrigerant to these positions, converting previously underutilized heat transfer area into effective cooling surface.
Solution Approach 2:
Different paths are assigned to different row positions based on local requirements. Paths are configured to supply refrigerant to specific rows where heat exchange is most needed. This local optimization ensures that each region of the heat exchanger receives refrigerant at appropriate temperatures and flow rates, maximizing the effective utilization of heat transfer area across all rows.
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 heat exchange efficiency in downstream rows and overall cooling capacity by optimizing refrigerant flow and airflow distribution, particularly in areas with low airflow velocities.
Implementation Method 1
heat exchange is performed between the refrigerant in these heat transfer tubes and indoor air to thereby adjust a temperature of the indoor air to a desired value
Implementation Method 2
heat transfer tubes in which a refrigerant is caused to flow are provided, and heat exchange is performed between the refrigerant
Implementation Method 3
a fan that generates an airflow passing through the heat exchanger
Data Source
AI summary
There is provided a heat exchanger of an air conditioning device capable of improving heat exchange efficiency in heat transfer tubes arranged in downstream rows in an airflow direction to enhance cooling capacity. In the heat exchanger of the air conditioning device, a plurality of heat transfer tubes arrayed in three or more rows in the airflow direction are provided, and a refrigerant is distributed to a plurality of paths to be supplied to the heat transfer tubes, and the heat exchanger is used as a evaporator during cooling operation. The plurality of paths include a most downstream path made up of only the heat transfer tubes in a most downstream row in the airflow direction, and an upstream path made up of only the heat transfer tubes in a plurality of rows arranged on an upstream side of the most downstream path.