Indoor unit for air conditioning device
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Solution Overview
Problem
The indoor unit of an air conditioner with a cross-flow fan experiences increased air flow resistance due to a large inclination angle of the heat exchanger, which impairs fan performance when attempting to reduce this angle to prevent contact with the fan rotor.
Innovation Solution
The heat exchanger is arranged with its inclined portion positioned further rearward and more vertically, with the front end located below the fan rotor and between the tongue portion and center axis, allowing for reduced air flow resistance without impairing fan performance by ensuring air reaches the suction port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the inclination angle of the heat exchanger is reduced to prevent contact with the fan rotor, then the air flow resistance is reduced, but the air flow may fail to reach the suction port, decreasing the effective suction area and impairing fan performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the inclination angle of the heat exchanger and the position of its front end. The inclination angle is set to 5° to 15° (optimally 7° to 12°), and the front end is positioned between 30% to 70% (optimally 40% to 60%) of the distance from the fan rotor's foremost portion to its center axis. These parameter optimizations simultaneously reduce air flow resistance and ensure adequate air flow reaches the suction port, resolving the contradiction between reducing resistance and maintaining fan performance.
2Productivity
If the heat exchanger is arranged with a larger heat transfer area, then the heat exchange efficiency is improved, but the air flow resistance increases due to the inclined portion making contact with the drain pan
Solution Approach 1:
The patent resolves this contradiction by optimizing two key parameters: the inclination angle of the heat exchanger is controlled at 5° to 15°, and the position of the front end is set between 30% to 70% of the distance from the fan rotor's foremost portion to its center axis. These parameter optimizations allow the heat exchanger to achieve a larger heat transfer area while preventing the inclined portion from making contact with the drain pan, thereby maintaining low air flow resistance.
3Object-affected harmful factors
If the inclined portion of the heat exchanger is shifted rearward to reduce the inclination angle, then the air flow resistance is reduced, but the air flow path length increases and may not reach the suction port
Solution Approach 1:
The patent applies parameter changes by precisely controlling both the inclination angle (5° to 15°) and the horizontal position of the heat exchanger's front end (30% to 70% of the distance from the fan rotor's foremost portion to its center axis). This dual parameter optimization ensures that the air flow path length remains adequate for air to reach the suction port while the inclination angle is reduced enough to minimize air flow resistance, resolving the contradiction between these two factors.
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 reduces air flow resistance and energy consumption while maintaining effective suction area, allowing for a larger heat transfer area in a compact space.
Implementation Method 1
a heat exchanger (40) arranged upstream of the cross-flow fan (30) in the casing (20) in a direction of the air flow to heat or cool the air passing through the heat exchanger (40)
Implementation Method 2
the cross-flow fan (30) forming in the casing (20) an air flow directed from the rear inflow port (21) to the front outflow port (22)
Data Source
AI summary
Disclosed is an indoor unit of an air conditioner including: a casing; a cross-flow fan arranged in the casing and having a fan rotor and a tongue portion extending in an axial direction along an outer periphery of the fan rotor below the fan rotor and forward of a center axis of the fan rotor to define a suction port, the cross-flow fan forming in the casing an air flow directed from the rear to the front; and a heat exchanger arranged upstream of the fan in a direction of the air flow and having an inclined portion inclined to be positioned further downward toward a front side. The heat exchanger is arranged such that a front end of the inclined portion is located below the fan rotor and between a foremost portion and center axis of the fan rotor in a front-to-back direction.