Outdoor unit for air-conditioning apparatus, and air-conditioning apparatus including the same
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Solution Overview
Problem
Existing outdoor units for air-conditioning apparatuses face issues with corrosion due to bimetallic contact between steel and aluminum components, leading to potential refrigerant leakage, and inefficient drainage due to sedimentation and clogging, which hinders water discharge.
Innovation Solution
An outdoor unit design featuring a separation member between the heat exchanger and bottom plate, with a drainage passage and holes that protrude vertically, inclined to prevent overflow and sedimentation, and a width larger than the heat exchanger to enhance airflow, ensuring efficient water discharge and reducing corrosion risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spacer is provided between the bottom plate and heat exchanger to suppress electrolytic corrosion, then corrosion resistance is improved, but the drainage passage may be blocked by sediments or water overflow may occur depending on spacer shape
Solution Approach 1:
The bottom plate is segmented into a drainage passage region and a support region. The heat exchanger is positioned on the support region while the drainage passage remains clear and unobstructed, allowing sediments to be directed toward designated collection areas rather than blocking the drainage path.
Solution Approach 2:
A groove structure acts as an intermediary element between the heat exchanger and the drainage passage. This groove guides sediments away from the drainage hole while maintaining the separation between the heat exchanger and bottom plate, preventing direct blockage of the drainage path.
2Productivity
If the drain reservoir recess portion is inclined to concentrate drain water flow to one drainage hole, then drainage efficiency is improved, but drainage becomes difficult when the drainage hole is clogged
Solution Approach 1:
The bottom plate features localized drainage passages and multiple drainage holes distributed at different positions. Each region has optimized local drainage characteristics, allowing water to drain through multiple paths rather than concentrating on a single hole, thus maintaining reliability while preserving efficiency.
3Ease of operation
If sediments stagnate in the groove formed in the drain reservoir recess portion, then the drainage passage may be entirely closed, but the groove is necessary to guide drain water
Solution Approach 1:
The drainage system utilizes vertical dimension with drainage passages extending downward from the bottom plate surface. Multiple drainage holes are positioned at different vertical levels and horizontal positions, creating a three-dimensional drainage network that prevents complete blockage even when sediments accumulate in certain areas.
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 design effectively suppresses corrosion and enhances water drainage efficiency by preventing bimetallic contact and sediment accumulation, thereby extending the unit's lifespan and ensuring reliable operation.
Implementation Method 1
the drainage passage comprising a drainage surface inclined downward in the vertical direction toward one of the one or the plurality of drain holes
Implementation Method 2
bimetallic contact is caused between iron and aluminum or aluminum alloy. As a result, in the heat exchanger which is made of aluminum or aluminum alloy being electrically less noble than iron, there may occur pitting corrosion being electrolytic corrosion caused by formation of a local cell
Data Source
AI summary
An outdoor unit for an air-conditioning apparatus includes a heat exchanger; a bottom plate; and a separation member configured to separate the bottom plate and the heat exchanger. The bottom plate includes a drainage passage that protrudes downward; and one or more drainage holes each formed to protrude downward from the drainage passage. The drainage passage includes a drainage surface inclined downward toward the one drain hole having a width larger than a width of the heat exchanger. The separation member is formed of a metal electrically less noble than a member forming the heat exchanger, or a resin member. The separation member is provided in the drainage passage and shaped to prevent closing of the drainage passage, in which a height to a surface on which the heat exchanger is placed is larger than a height to an upper surface of the drainage passage.