Cross-Counterflow Tube Bank Heat Exchanger With Integral Manifolds
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Solution Overview
Problem
Conventional air-cooled chiller systems with double bank flattened tube and serpentine fin heat exchangers face complexity in fluid flow communication and alignment, requiring intricate external piping and precise alignment, which limits their efficiency and flexibility.
Innovation Solution
A multiple tube bank heat exchanger design featuring two slabs with integral manifolds and flattened tube segments in a cross-counterflow arrangement, where each tube bank has separate manifolds and is connected via internal web members, allowing for flexible refrigerant circuiting and improved structural support, reducing thermal mechanical fatigue and enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional double bank flattened tube heat exchangers are used with external piping to connect manifolds, then fluid flow communication between banks is achieved, but device complexity and alignment precision requirements increase
Solution Approach 1:
The patent merges the manifold connection function into the heat exchanger slab structure itself by using integral manifolds that are directly formed as part of the extruded slab. This eliminates the need for separate external piping connections between banks, thereby reducing device complexity and eliminating alignment precision requirements for connecting piping.
Solution Approach 2:
The patent introduces web members as intermediary structural elements that are integrally formed with the manifolds and provide both structural support and fluid flow communication pathways between banks. These web members act as built-in conduits that replace complex external piping while maintaining structural integrity.
2Ease of manufacture
If cross-flow configuration is used in single slab heat exchangers, then manufacturing is simplified, but heat transfer efficiency is limited
Solution Approach 1:
The patent transitions from a single-slab cross-flow configuration to a multi-slab arrangement where slabs are positioned at angles to each other (e.g., perpendicular or at 45 degrees). This spatial reconfiguration in multiple dimensions enables counterflow heat exchange patterns while maintaining the manufacturing simplicity of extruded slab structures, thereby improving heat transfer efficiency without sacrificing ease of manufacture.
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 cross-counterflow arrangement enhances heat exchange performance, reduces refrigerant pressure drop, and simplifies refrigerant circuiting, providing superior thermal efficiency and flexibility in managing pressure drops, while minimizing thermal mechanical fatigue and facilitating easier installation and handling.
Implementation Method 1
heat transfer between a fluid, commonly air in HVACR applications, flowing over the outside surfaces of the flattened tubes and along the fin surfaces and a fluid, commonly refrigerant in HVACR applications, flowing inside the flattened tubes
Implementation Method 2
heat transfer between a fluid, commonly air in HVACR applications, flowing over the outside surfaces of the flattened tubes and along the fin surfaces
Data Source
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AI summary
An air-cooled chiller system includes a heat exchanger including a first tube bank including at least a first and a second flattened tube segments extending longitudinally in spaced parallel relationship; a second tube bank including at least a first and a second flattened tube segments extending longitudinally in spaced parallel relationship, the second tube bank disposed behind the first tube bank with a leading edge of the second tube bank spaced from a trailing edge of the first tube bank; a fan creating an airflow across the first heat exchanger, the airflow flowing over the first tube bank prior to flowing over the second tube bank, wherein refrigerant flows in the heat exchanger in a cross-counterflow direction opposite that of the airflow direction.