Cross-Flow Fan Heat Exchanger Layout for Lower Suction Loss
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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 an excessively large inclination angle of the heat exchanger's inclined portion, which, when reduced to avoid contact with the fan rotor, can impair the fan's performance by decreasing the effective suction area.
Innovation Solution
The heat exchanger is arranged with a bent shape surrounding the suction port, positioning its inclined portion more vertically and further rearward, ensuring air flow reaches the suction port without reducing the fan's performance, and maintaining a compact design with a large heat transfer area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inclination angle of the inclined portion is reduced to avoid contact with the fan rotor, then the air flow resistance is reduced, but the effective suction area of the fan decreases, impairing fan performance
Solution Approach 1:
The heat exchanger is repositioned in the vertical dimension by utilizing the space between the fan rotor and the casing bottom surface. The inclined portion is positioned such that its front end is located below the fan rotor and between the foremost portion and center axis of the fan rotor in the front-to-back direction, effectively using vertical space to resolve the horizontal space conflict.
Solution Approach 2:
The inclined portion of the heat exchanger is nested within the spatial envelope defined by the fan rotor and casing boundaries. By positioning the inclined portion between the fan rotor and the bottom surface of the casing, the design nests the heat exchanger into available space without interfering with fan operation.
2Productivity
If the heat exchanger is arranged with a large heat transfer area in a compact casing, then the heat exchange efficiency is improved, but the air flow resistance increases due to the inclined portion contacting the drain pan
Solution Approach 1:
The heat exchanger utilizes the vertical dimension by positioning its inclined portion between the fan rotor and the bottom surface of the casing. This vertical arrangement allows the heat exchanger to achieve a large heat transfer area within a compact horizontal footprint while avoiding contact with the drain pan, thus maintaining low air flow resistance.
Solution Approach 2:
The heat exchanger is designed with a specific local configuration where the inclined portion is positioned at a precise location below the fan rotor. This local positioning ensures that the heat exchanger maintains its heat transfer functionality while avoiding the harmful contact with the drain pan that would increase air flow resistance.
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 the fan's performance by positioning the heat exchanger's inclined portion in a more vertical posture, ensuring effective suction and compact space utilization.
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
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is an indoor unit (10) of an air conditioner including: a casing (20); a cross-flow fan (30) arranged in the casing (20) and having a fan rotor (31) and a tongue portion (36a) extending in an axial direction along an outer periphery of the fan rotor (31) below the fan rotor (31) and forward of a center axis (X) of the fan rotor (31) to define a suction port (32a), the cross-flow fan (30) forming in the casing (20) an air flow directed from the rear to the front; and a heat exchanger (40) arranged upstream of the fan (30) in a direction of the air flow and having an inclined portion (44) inclined to be positioned further downward toward a front side. The heat exchanger (40) is arranged such that a front end (44a) of the inclined portion (44) is located below the fan rotor (31) and between a foremost portion (31a) and center axis (X) of the fan rotor (31) in a front-to-back direction.