Alternating Symmetrical Asymmetrical Plate Heat Exchanger
Solution Overview
Problem
Symmetric plate heat exchangers often result in suboptimal mass flux for both fluids, leading to underperforming refrigerant-side heat transfer and excessive liquid-side pressure drop, while asymmetric designs have their own limitations, limiting the capacity of heat exchangers.
Innovation Solution
A plate heat exchanger design incorporating a combination of symmetric and asymmetric plates with specific geometric features, such as cosine wave cross-sectional shapes and chevron angles, to optimize fluid flow and thermal energy exchange, with asymmetric plates defined by a two-term Fourier cosine series and alternating stacking to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If symmetric plates are used in the plate heat exchanger, then the structure is simple and easy to manufacture, but the mass flux for both fluids becomes suboptimal leading to underperforming refrigerant-side heat transfer and excessive liquid-side pressure drop
Solution Approach 1:
The patent applies asymmetry by introducing asymmetric plates with non-uniform wave patterns into the heat exchanger stack. These asymmetric plates create different flow channel geometries for the two fluid streams, allowing optimization of mass flux distribution. The asymmetric geometry enables one fluid to experience enhanced turbulence and heat transfer while the other maintains appropriate flow velocity, resolving the suboptimal mass flux issue of symmetric designs without sacrificing manufacturability since the asymmetric plates are still produced using standard fabrication processes.
2Productivity
If asymmetric plates are used in the plate heat exchanger, then the mass flux optimization improves, but the design complexity increases and limitations remain that cap the heat exchanger capacity
Solution Approach 1:
The patent applies local quality by combining symmetric and asymmetric plates in a specific alternating sequence within the heat exchanger stack. This creates localized zones with different flow characteristics - symmetric plates provide stable, predictable flow paths while asymmetric plates create turbulence and enhance heat transfer in specific regions. The alternating arrangement allows the system to benefit from both symmetric and asymmetric geometries without requiring the entire stack to be complex, thus improving mass flux optimization while controlling overall design complexity.
3Reliability
If traditional symmetric or asymmetric plate designs are used, then the heat exchanger meets basic performance requirements, but the capacity is limited and material requirements are excessive
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the plate wave patterns, specifically the wavelength-to-amplitude ratio. By setting this ratio to specific values, the plate geometry is optimized to enhance heat transfer coefficients and improve fluid distribution. This parameter optimization allows the heat exchanger to achieve higher capacity with fewer plates or smaller overall size, reducing material requirements while maintaining and enhancing basic performance reliability. The specific geometric parameters enable more efficient thermal energy exchange per unit volume of the exchanger.
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 achieves a 30% reduction in material requirements, up to 50% reduction in refrigerant charge, and a 2X capacity increase within the same physical envelope, offering cost savings and improved performance compared to traditional designs.
Implementation Method 1
the PHE or BPHE facilitating thermal energy exchange between the two fluids
Implementation Method 2
Each main plate has one or more peaks and one or more valleys formed therein. A ratio of wavelength between adjacent peaks or between adjacent valleys of the main plate to an amplitude between a peak and an adjacent valley of the main plate is equal to or greater than 7.0
Data Source
AI summary
A plate heat exchanger includes a plurality of main plates stacked to define a first cavity to direct a first fluid therethrough and a second cavity to direct a second fluid therethrough, the second fluid different from and kept separated from the first fluid. Each main plate has one or more peaks and one or more valleys formed therein. A ratio of wavelength between adjacent peaks or between adjacent valleys of the main plate to an amplitude between a peak and an adjacent valley of the main plate is equal to or greater than 7.0.