Indoor Heat Exchanger Rectifying Plates for Quieter Airflow
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Solution Overview
Problem
The existing ceiling buried-type air conditioners with fin tube-shaped heat exchangers experience increased ventilation resistance due to the disposition of wind guide plates, which also fail to effectively reduce blowing noise generated by wind colliding against fins.
Innovation Solution
The air conditioner incorporates rectifying plates attached to the heat exchanger on the inner peripheral side, extending parallel to the rotational shaft, with specific positioning and angles to reduce the velocity component of the blowing wind and minimize ventilation resistance, thereby reducing noise without significantly increasing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If curved wind guide plates are disposed at centers inside four sides of the heat exchanger, then blowing noise is reduced, but ventilation resistance significantly increases
Solution Approach 1:
The heat exchanger is divided into multiple planar portions, and rectifying plates are selectively disposed at specific positions (upstream and downstream of the closest position to the fan) rather than uniformly across all sides. This segmented approach reduces noise at critical locations while maintaining ventilation efficiency in other areas.
Solution Approach 2:
Rectifying plates are disposed only at specific local positions (upstream and downstream of the closest position to the fan) rather than uniformly across the entire heat exchanger. This localized approach targets noise reduction where it is most needed while minimizing the overall impact on ventilation resistance.
2Object-affected harmful factors
If rectifying plates are disposed to reduce blowing noise, then noise level decreases, but the complexity of the device increases
Solution Approach 1:
The rectifying plates are segmented into a specific number (two or more per planar portion) and disposed at specific positions (upstream and downstream of the closest position) rather than uniformly across all sides. This reduces the total number of plates needed compared to comprehensive coverage, thereby reducing device complexity while still achieving noise reduction.
Solution Approach 2:
Rectifying plates are disposed only at specific local positions where noise reduction is most effective (upstream and downstream of the closest position to the fan), rather than uniformly across the entire heat exchanger. This selective disposition reduces the total number of components and simplifies the overall device structure.
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 effectively reduces blowing noise generated by wind colliding against fins while maintaining low ventilation resistance, as demonstrated by the reduced sound pressure levels and optimized turbulence generation.
Implementation Method 1
a velocity component of the blowing wind in the rotational direction is reduced due to turbulence generated by the first rectifying plate before reaching the closest position
Data Source
Figure 1
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AI summary
To reduce blowing noise generated by blowing wind colliding against fins without significantly increasing a ventilation resistance. Provided is an air conditioner including: an indoor heat exchanger 18 that is disposed so as to surround an outer periphery of a turbofan 17; and a plurality of rectifying plates 32 that is attached to the indoor heat exchanger 18 on an inner peripheral side, in which the indoor heat exchanger 18 has a plurality of planar portions that is disposed along a plane that perpendicularly intersects a radial direction at a closest position P1 to the turbofan 17 and a plurality of curved portions that couples these planar portions, a first rectifying plate 32A is attached to the first planar portion 18A at a first predetermined position on an upstream side in a rotational direction Rd of the turbofan 17 beyond the closest position P1 while a second rectifying plate 32B is attached thereto at a second predetermined position on a downstream side in the rotational direction Rd of the turbofan 17 beyond the closest position P1, and the first rectifying plate 32A and the second rectifying plate 32B are disposed to be adjacent to each other.