Outdoor Unit Heat Exchanger Layout for Uniform Airflow
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Solution Overview
Problem
In upward-air-outlet-type outdoor units of air-conditioning apparatuses, nonuniform wind speed distribution leads to increased pressure drop and fan noise due to varying distances between the heat exchanger and fan, causing energy loss and higher electric power consumption.
Innovation Solution
The outdoor unit design features a housing with different widths in short-side and long-side directions, where the upper part has a longer width in the short-side direction, incorporating L-shaped heat exchangers and a specific layout of heat exchangers and side-surface panels to ensure uniform airflow distribution and reduce pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the heat exchanger is disposed in each of four side surfaces of an upper part of the housing in a box shape having different widths in short-side and long-side directions, then the volume of the heat exchanger is increased while the installation area is maintained, but the distance between the heat exchanger and the fan differs between the long-side and short-side directions, leading to nonuniform wind speed distribution and increased pressure drop
Solution Approach 1:
The patent applies local quality by configuring the housing with different widths in short-side and long-side directions at different locations. Specifically, the upper part of the housing has a longer width in the short-side direction compared to the lower part, creating localized dimensional variations that compensate for the asymmetric placement of heat exchangers. This local dimensional adjustment ensures that the distance from each heat exchanger to the fan remains substantially equal, thereby maintaining uniform wind speed distribution across all heat exchanger surfaces while maximizing the total heat exchanger volume within the available installation area.
2Productivity
If the wind speed through the heat exchanger is large in the short-side direction due to short distance between heat exchanger and fan, then the heat exchange capacity is improved, but the passing wind resistance increases and pressure drop in the outdoor unit increases
Solution Approach 1:
The patent applies parameter changes by modifying the housing dimensions in the short-side direction at the upper part. By increasing the width in the short-side direction at the upper part of the housing, the patent adjusts the spatial parameters to equalize the distance between the fan and heat exchangers across different directions. This parameter adjustment balances the wind speed distribution, preventing excessively high wind speeds in the short-side direction that would cause increased passing wind resistance and pressure drop, while still maintaining sufficient heat exchange capacity through optimized heat exchanger volume.
3Speed
If the wind speed distribution is nonuniform and increases along the rotational direction of the fan, then the airflow capacity is improved, but disorder in flow occurs right before suction by the fan, causing energy loss around vanes and increased fan noise
Solution Approach 1:
The patent applies asymmetry by intentionally designing the housing with different widths in the short-side and long-side directions, and by asymmetrically placing heat exchangers on side surfaces. This asymmetric configuration is deliberately structured to compensate for the fan's rotational flow pattern. The asymmetric housing dimensions create a flow distribution that counterbalances the tendency for wind speed to increase along the rotational direction, preventing flow disorder before the fan suction. This resolves the energy loss around fan vanes and reduces fan noise while maintaining adequate airflow capacity.
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 achieves noise reduction and improved heat exchange efficiency by providing a uniform air path without increasing the installation area, resulting in reduced electric power consumption and noise levels.
Implementation Method 1
airflow generated by rotation of a fan flows through a heat exchanger to exchange heat between outside air and refrigerant
Implementation Method 2
airflow generated by rotation of a fan flows through a heat exchanger to exchange heat between outside air and refrigerant
Data Source
Figure 1
Figure 2
Figure 3~3a
AI summary
An outdoor unit (1) of an air-conditioning apparatus includes a housing (2) having a box shape and including air inlets (4a and 4b) formed on side surfaces and an air outlet (10) formed on an upper surface, a fan (12) provided to an upper side in the housing (2) and configured to discharge, through the air outlet (10), outside air sucked through the air inlets (4a and 4b), and a heat exchanger (5) provided in the housing (2) along each of the air inlets (4a and 4b). The heat exchanger (5) includes an upper heat exchanger (5a) disposed at an upper part of the housing (2) and a lower heat exchanger (5b) disposed at a lower part of the housing (2). In plan view, the housing (2) has different widths in short-side and long-side directions, and the width in the short-side direction at the upper part of the housing (2) is longer than the width in the short-side direction at the upper part of the housing (2).