Asymmetric Plate Heat Exchanger Channels for Lower Pressure Drop

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Modern plate heat exchangers with herringbone patterns face issues such as material distortion, high pressure drop, uneven fluid flow rates, reduced heat transfer efficiency, and mechanical instability due to thick metal sheets and uneven solder distribution, especially when handling fluids with different properties.

Innovation Solution

Designing heat exchanger plates with alternating patterns of different indentation densities and shapes to create distinct fluid channels, allowing for tailored mechanical stability and fluid flow characteristics, reducing pressure drop and enhancing heat transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick metal sheets are used to withstand high pressures, then pressure resistance is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvepressure resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the plate structure by introducing specific indentation patterns (ridges and valleys) that alter the mechanical properties of the plate. These geometric modifications enable thinner plates to achieve the required pressure resistance without increasing manufacturing complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs curved surfaces through the indentation pattern, where ridges and valleys create non-planar geometries that enhance structural strength. The curved surfaces distribute stress more effectively, allowing thinner plates to withstand high pressures

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Area of stationary object

If herringbone pattern indentations are pressed into metal sheets, then heat exchange surface area is improved, but material flow becomes unfavorable and cracks may appear

Engineering Contradiction:
Improveheat exchange surface areaVSAvoidplate integrity
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent modifies the indentation parameters by adjusting ridge angles, valley depths, and spacing to optimize both heat exchange area and material flow during pressing. The specific geometric parameters are chosen to minimize stress concentrations that cause cracking

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different indentation characteristics in different regions of the plate. The ridge and valley dimensions are locally optimized to accommodate varying material flow requirements across the plate surface, preventing crack formation in high-stress areas

Inventive Principle:
Principle #3Local quality

3Strength

If copper or copper alloy solder is used in fully brazed joints, then joint strength is improved, but solder distribution becomes uneven and surface area for soldering is reduced

Engineering Contradiction:
Improvejoint strengthVSAvoidsolder surface area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The patent creates localized zones with different indentation characteristics that control solder flow and distribution. Specific ridge and valley configurations are designed to trap and distribute solder uniformly across joint areas, maximizing the effective solder surface area

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The indentation pattern acts as an intermediary structure that mediates solder distribution. The ridges and valleys serve as channels and reservoirs that guide copper solder to achieve uniform distribution across the joint surfaces

Inventive Principle:
Principle #24Intermediary (Mediator)

4Power

If fluid is forced to flow over ridges and down into valleys in herringbone pattern, then heat transfer rate is improved where flow rate is high, but pressure drop increases and heat transfer rate decreases where flow rate is low

Engineering Contradiction:
Improveheat transfer rateVSAvoidpressure drop
Core Design Contradiction:
PowerVSStress or pressure

Solution Approach 1:

The patent optimizes the geometric parameters of ridges and valleys to control fluid flow characteristics. By adjusting ridge angles, heights, and spacing, the patent achieves a balance between generating sufficient turbulence for heat transfer and minimizing pressure drop

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial herringbone patterns or combines them with straight channel sections. This allows heat transfer enhancement in specific regions while maintaining lower pressure drop in other regions, achieving an optimal balance

Inventive Principle:
Principle #16Partial or excessive action

5Power

If two-phase fluid flows through herringbone pattern heat exchanger, then heat exchange occurs, but gas forces liquid away from contact with plates reducing wetting and heat transfer rate

Engineering Contradiction:
Improveheat exchangeVSAvoidwetting efficiency
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent creates specific local geometries in the indentation pattern that promote liquid retention. Certain valley configurations and ridge angles are designed to counteract gas forces and maintain liquid contact with the plate surfaces in two-phase flow conditions

Inventive Principle:
Principle #3Local quality

6Ease of manufacture

If indentations are made with equal number on both sides of the plate, then manufacturing simplicity is improved, but mechanical stability and fluid flow optimization are compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmechanical stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent employs asymmetric indentation patterns where the number, size, or distribution of ridges and valleys differs between the two sides of the plate. This asymmetry is specifically designed to optimize mechanical stability under pressure differentials and to control fluid flow characteristics for enhanced heat transfer performance

Inventive Principle:
Principle #4Asymmetry

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 solution provides improved mechanical stability, reduced pressure drop, and increased heat transfer efficiency by optimizing fluid flow and channel design, while allowing for thinner metal usage and reduced manufacturing costs.

Implementation Method 1

the resulting heat exchanger pack comprises a pattern of fluid channels through which the respective two fluids can flow and exchange their thermal energy

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

A fluid which is made to flow through a heat exchanger with a herringbone pattern is forced to flow over the ridges and down into the valleys

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2455695B1Heat exchanger
Publication Date: 2019.10.09 DANFOSS AS
  • EP2455695B1 patent drawingFigure 1~2
  • EP2455695B1 patent drawingFigure 3~4
  • EP2455695B1 patent drawingFigure 5~6

AI summary

The invention relates to a plate heat exchanger (9) with a plurality of heat exchanger plates (1, 13), each comprising at least one section showing indentations (2, 3, 14, 15), intended to be placed against corresponding indentations (2, 3, 14, 15) of a heat exchanger plate (1, 13) of a corresponding design. The heat exchanger (9) has a first type of indentations (2, 14) and a second type of indentations (3, 15), wherein the number of said first type of indentations (2, 14) and said second type of indentations (3, 15) are differing.