Heat Exchanger Fin Slit Layout for Low Pressure Loss Cooling
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Solution Overview
Problem
Conventional fin-and-tube type heat exchangers face challenges in enhancing heat transfer efficiency while minimizing ventilation resistance, as excessive cut-up members increase pressure loss and reduce airflow, and the arrangement of refrigerant pipes further complicates heat transfer optimization.
Innovation Solution
The design incorporates cut-up members on fins with optimized dimensions and angles to maximize heat transfer coefficients while controlling ventilation resistance by adjusting the slit height and fin pitch, ensuring the slit height to fin pitch ratio falls within 0.5 to 0.7, and strategically positioning refrigerant pipes to reduce dead regions and airflow obstacles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the height of the cut-up member becomes excessively large, then the heat transfer coefficient increases, but the ventilation resistance becomes large and pressure loss increases
Solution Approach 1:
The patent optimizes the height of the cut-up member within a specific range (0.05 to 0.15 times the fin pitch) to achieve the best balance between heat transfer coefficient and ventilation resistance. This parameter optimization resolves the contradiction by identifying the critical value where heat transfer improvement is maximized while ventilation resistance increase is minimized.
2Temperature
If the cut-up member is formed on the fin, then the local heat transfer coefficient increases, but the distance between adjacent fins and cut-up member becomes small, increasing ventilation resistance
Solution Approach 1:
The cut-up member is strategically positioned at the leading edge of the fin where the temperature boundary layer first forms. This localized modification creates new temperature boundary layers at critical positions, maximizing local heat transfer coefficient improvement while minimizing the overall impact on fin spacing and ventilation resistance.
3Temperature
If refrigerant pipes are arranged to improve heat transfer, then heat transfer efficiency increases, but airflow obstacles and dead regions increase
Solution Approach 1:
The refrigerant pipes are arranged in a staggered pattern alternating between even and odd fin rows, utilizing the third dimension (depth/layering) to distribute pipes more evenly throughout the heat exchanger. This dimensional arrangement reduces localized airflow obstacles and dead regions while maintaining effective heat transfer across all fin rows.
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 optimizes both heat transfer performance and ventilation resistance, achieving maximum heat transfer efficiency with minimal pressure loss, as demonstrated by simulations and performance evaluations across various cooling capacities.
Implementation Method 1
when air passes through a flat-plate-shaped fin without a cut-up member, a temperature boundary layer is formed from an air inlet end of the fin, and the temperature boundary layers of each fin come into contact with each other
Implementation Method 2
the local heat transfer coefficient becomes lower at the same time as the temperature boundary layer develops, and the heat transfer coefficient becomes constant
Implementation Method 3
in a so-called fin-and-tube type heat exchanger, in order to increase the heat exchange efficiency
Data Source
Figure 1
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Figure 3
AI summary
An air conditioner including a heat exchanger according to an aspect of the present disclosure, the heat exchanger includes a refrigerant pipe, and a plurality of fins including a first fin and a second fin spaced apart from each other in an extending direction of the refrigerant pipe, wherein the first fin includes a flat portion and a cut-up member protruding in an arrangement direction of the second fin in the flat portion, and the height of the cut-up member in the extension direction is between 0.5 and 0.7 times the distance between the first fin and the second fin.