Vortex-enhanced heat exchanger
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current HVAC&R systems using round-tube plate-fin heat exchangers in evaporator sections face inefficiencies due to rudimentary fin designs, leading to large size, high weight, and increased costs, with existing fin enhancements becoming ineffective under frosting conditions.
Innovation Solution
Incorporating vortex generators of triangular or rectangular shapes positioned at a nonzero angle relative to airflow, creating nozzle-like passages between heat exchange tubes, which enhance convective heat transfer and frost distribution while maintaining low pressure drop and cost-efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rudimentary fin designs are used in round-tube plate-fin heat exchangers, then manufacturing cost and complexity are reduced, but thermal energy performance is insufficient requiring large fin surface areas
Solution Approach 1:
The patent applies local quality by adding vortex generators only at specific locations (upstream of tube rows) rather than modifying the entire fin structure. This localized enhancement improves thermal performance at the heat transfer bottleneck while keeping manufacturing simple and costs low.
Solution Approach 2:
The vortex generators change the flow parameters (creating vortices and mixing) to enhance heat transfer coefficients. This parameter change allows achieving better thermal performance without increasing fin surface area or complexity.
2Productivity
If large fin surface areas are used to meet performance requirements, then thermal energy performance is improved, but heat exchanger size, weight, and cost increase
Solution Approach 1:
The vortex generators modify flow parameters to enhance heat transfer coefficients, allowing the system to achieve the same thermal performance with a smaller heat exchanger size and less material, thereby reducing weight.
Solution Approach 2:
The vortex generators create asymmetric flow patterns with controlled vortices that enhance mixing and heat transfer. This asymmetric flow manipulation improves thermal performance without requiring proportional increases in heat exchanger size.
3Productivity
If surface interruption enhancements like lances and louver geometries are used, then thermal performance is improved, but effectiveness is lost under frosting conditions due to blockage
Solution Approach 1:
The vortex generators are positioned locally upstream of tube rows where flow separation occurs, creating vortices that enhance heat transfer without blocking the fin surfaces. This local enhancement maintains effectiveness under frosting conditions unlike surface interruptions.
Solution Approach 2:
Instead of interrupting the fin surface (which gets blocked by frost), the patent uses protruding vortex generators upstream of tubes to create beneficial flow patterns. This inverted approach enhances heat transfer without creating blockage points on the fin surfaces.
4Productivity
If vortex generators are positioned at nonzero angle of attack, then convective heat transfer is enhanced, but device complexity increases
Solution Approach 1:
The vortex generators are positioned at specific angles of attack to optimize vortex strength and heat transfer enhancement. This parameter optimization achieves maximum thermal performance with a relatively simple geometric configuration that remains manufacturable.
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
The configuration improves thermal energy performance, reduces the overall size of the heat exchanger, and maintains efficiency even under frosting conditions without significant pressure drop penalties, while being cost-effectively manufactured.
Implementation Method 1
a plurality of vortex generators extending from a fin surface of the plurality of fins. The plurality of vortex generators are arranged to define nozzle like passages at the heat exchange tubes
Implementation Method 2
enhance convective heat transfer and frost distribution while maintaining low pressure drop
Implementation Method 3
a plurality of heat exchange tubes configured for flowing a refrigerant therethrough
Implementation Method 4
enhance convective heat transfer
Implementation Method 5
a plurality of fins positioned such that the plurality of heat exchange tubes pass through a plurality of tube openings in the plurality of fins
Data Source
AI summary
A tube and fin heat exchanger includes a plurality of heat exchange tubes configured for flowing a refrigerant therethrough, a plurality of fins positioned such that the plurality of heat exchange tubes pass through a plurality of tube openings in the plurality of fins, and a plurality of vortex generators extending from a fin surface of the plurality of fins. The plurality of vortex generators are arranged to define nozzle like passages at the heat exchange tubes.