Variable Fin Spacing Heat Exchanger for Delayed Frost Formation
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Solution Overview
Problem
In heat exchangers, the formation of frost on the fin surface can block airflow and reduce heat exchange efficiency, particularly at the front end where the temperature difference is greater, leading to increased defrosting time and reduced performance.
Innovation Solution
A heat exchanger design with varying fin spacings and louver configurations, where the distance between fins is greater at the front end than at the rear end, and the number of ruled surfaces and louver angles are adjusted to delay frost formation, ensuring efficient airflow and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the stacked distance between fins is reduced to increase heat exchange area, then the heat exchange area increases, but frost blocks the passage more easily and heat exchange efficiency deteriorates
Solution Approach 1:
The patent applies different stacked distances between fins at different locations: the front end-side (upstream) has a larger stacked distance to prevent frost blocking, while the rear end-side (downstream) has a smaller stacked distance to maximize heat exchange area. This local differentiation resolves the contradiction by optimizing each region for its specific function.
Solution Approach 2:
The heat exchanger is segmented into front end-side and rear end-side regions with different fin configurations. The front region prioritizes frost prevention with larger spacing, while the rear region prioritizes heat exchange with smaller spacing, allowing both requirements to be satisfied simultaneously in different segments.
2Area of stationary object
If the stacked distance between fins is reduced, then more fins can be stacked to increase heat exchange area, but the time taken for defrosting increases
Solution Approach 1:
The front end-side fins are designed with larger stacked distances specifically to delay frost formation and reduce defrosting time in the region most prone to frosting, while other regions maintain smaller distances for maximum heat exchange area, thus resolving the time-area tradeoff locally where it matters most.
3Productivity
If the heat exchanger operates at low temperature to improve cooling performance, then cooling efficiency increases, but frost formation on fin surface increases
Solution Approach 1:
The patent recognizes that the front end-side is most affected by frost due to higher temperature difference with incoming air, and applies larger stacked distances specifically in this region to counteract frost formation, allowing the system to operate at low temperatures for improved cooling efficiency without excessive frost problems.
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 design effectively delays frost formation, maintains airflow, and enhances heat transfer performance by optimizing fin spacing and louver configurations, reducing the time taken to form frost and improving overall efficiency.
Implementation Method 1
a refrigerant flowing into the tube or flat tube is heat-exchanged with an external fluid, for example, air
Implementation Method 2
the refrigerant is condensed or evaporated by the heat exchanger
Implementation Method 3
the fin increases a heat exchange area between the refrigerant flowing into the tube or flat tube and the external fluid
Data Source
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AI summary
Provided is a heat exchanger. The heat exchanger includes a plurality of refrigerant tubes through which a refrigerant flows, the plurality of refrigerant tube being disposed to be spaced apart from each other in one direction and a plurality of fins disposed between the plurality of refrigerant tubes. A distance between the fins disposed on a front end-side of the plurality of refrigerant tubes is greater than that between the fins disposed on a rear end-side of the plurality of refrigerant tubes.