Air conditioner
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Solution Overview
Problem
Reverse suction in air-conditioning apparatuses occurs due to pressure differences, leading to reduced air volume, increased noise, and scattering of water droplets, which existing solutions like bell-shaped members cannot completely prevent.
Innovation Solution
The implementation of deflectors that cause outlet airflow from the cross flow fan to impinge upon, generating stagnation pressure higher than atmospheric pressure, preventing reverse suction while maintaining a large air volume and reducing power consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bell-shaped members are provided at both ends of the cross flow fan to prevent reverse suction, then reverse suction is partially reduced, but air volume is significantly reduced and power consumption increases
Solution Approach 1:
The patent applies local quality by providing deflectors only at specific locations where reverse suction occurs (both ends of the cross flow fan in the rotational axis direction) rather than using bell-shaped members that would affect the entire fan structure. This localized approach prevents reverse suction at critical points while maintaining air volume through other fan regions.
Solution Approach 2:
The patent introduces deflectors as intermediary components that redirect airflow without significantly impeding overall air movement. These deflectors act as mediators between the fan blades and the external environment, managing reverse suction tendencies while allowing main airflow to pass through with minimal resistance.
2Object-affected harmful factors
If bell-shaped members are provided at both ends of the cross flow fan to prevent reverse suction, then reverse suction is partially reduced, but noise increases and power consumption increases
Solution Approach 1:
The deflectors are placed locally at the fan ends where reverse suction occurs, rather than using comprehensive bell-shaped enclosures. This localized intervention addresses the harmful effect with minimal impact on overall airflow dynamics, thereby reducing the additional power consumption that would result from larger structural modifications.
Solution Approach 2:
The deflectors are simple, lightweight components with minimal material usage compared to bell-shaped members. They provide the necessary airflow management function with minimal energy penalty, effectively acting as low-cost, low-mass solutions that do not significantly increase power consumption.
3Device complexity
If the cross flow fan length in rotational axis direction is made longer than air outlet length, then reverse suction occurs at both ends, but air volume is reduced
Solution Approach 1:
The patent segments the fan structure by extending it beyond the air outlet in the rotational axis direction, creating distinct regions: a central portion aligned with the air outlet and end portions extending beyond. This segmentation allows the central portion to maintain effective air delivery while the end portions are managed by deflectors to prevent reverse suction.
Solution Approach 2:
Deflectors are introduced as intermediary elements at the fan ends to manage the extended portions that would otherwise create reverse suction. These deflectors mediate between the extended fan structure and the external environment, allowing the longer fan design to be maintained without the penalty of reduced air volume.
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
Prevents reverse suction, enhances air volume, reduces noise and power consumption, and minimizes the scattering of water droplets by ensuring a higher stagnation pressure near the air outlet.
Implementation Method 1
causing the outlet airflow from the fan extension of the cross flow fan to impinge upon a corresponding one of the deflectors, thereby the stagnation pressure higher than the atmospheric pressure is generated near both ends of the air outlet in the longitudinal direction
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
In an indoor unit of an air-conditioning apparatus, a reverse flow of indoor air from the inside of a room into the air-conditioning apparatus occurring at each end of an air outlet in the longitudinal direction is suppressed and a larger air volume of a fan is maintained, thereby obtaining the air-conditioning apparatus with which power consumption and noise can be reduced. The length of a cross flow fan 8 in the rotational axis direction AX is longer than the length of an air outlet 3 in the longitudinal direction, and the cross flow fan 8 has a fan extension 8a positioned beyond each end of the air outlet 3 in the rotational axis direction AX. Deflectors 18 are provided in the air-conditioning apparatus main body. An outlet airflow blown from each fan extension 8a of the cross flow fan 8 impinges upon a corresponding one of the deflector 18. Furthermore, the shape of blade portions 13a of the fan extensions 8a of the cross flow fan 8 and the shape of blade portions 13b opposing the air outlet 3 are different from each other. The wind speed of the outlet airflow blown from the blade portion 13a is lower than the wind speed of an outlet airflow blown from the blade portion 13b.