Vehicle Evaporator Single-Path Tube Stack

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Solution Overview

Problem

Conventional evaporators in air conditioning circuits of motor vehicles face inefficiencies in heat exchange and pressure distribution, leading to non-uniform temperature and increased head losses due to remixing phenomena in collectors.

Innovation Solution

A stack of tubes with a single coolant fluid circulation path arranged in series, featuring a configuration of three plates forming a 'U' shaped circulation path that alternates directions to improve temperature uniformity and reduce head losses, with the tubes supplied in parallel to minimize remixing and enhance overall performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If conventional multi-pass evaporators with collectors are used, then heat exchange surface area is increased, but remixing phenomena occur causing non-uniform temperature distribution and increased head losses

Engineering Contradiction:
Improveheat exchange surface areaVSAvoidhead losses
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The evaporator is divided into multiple independent single-pass tubes instead of using collectors with multiple passes. Each tube operates independently as a separate circulation unit, eliminating the remixing phenomena that occur in conventional collector-based multi-pass designs while maintaining adequate heat exchange surface area through the stacking of multiple tubes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a planar two-dimensional arrangement with collectors to a three-dimensional stacked configuration of independent tubes. This dimensional change allows multiple single-pass tubes to be arranged vertically, providing sufficient heat exchange surface area without the harmful remixing effects of horizontal multi-pass collectors.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If conventional multi-pass evaporators are used, then heat exchange capacity is improved, but temperature uniformity deteriorates due to remixing in collectors

Engineering Contradiction:
Improveheat exchange capacityVSAvoidtemperature uniformity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The evaporator is segmented into multiple independent single-pass tubes, each maintaining uniform temperature throughout its length without the disruptive remixing effects of collectors. This segmentation preserves temperature stability while achieving adequate heat exchange capacity through the combined surface area of multiple tubes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a single multi-pass tube with collectors that causes temperature non-uniformity, the invention inverts the approach by using multiple independent single-pass tubes. This inversion eliminates the remixing phenomenon while maintaining or improving overall heat exchange capacity through parallel operation of multiple tubes.

Inventive Principle:
Principle #13The other way round (Inversion)

3Stability of the object's composition

If single-pass tubes are used, then temperature uniformity is improved, but heat exchange surface area is reduced

Engineering Contradiction:
Improvetemperature uniformityVSAvoidheat exchange surface area
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

Multiple independent single-pass tubes are merged into a stacked configuration to achieve the cumulative heat exchange surface area needed for adequate cooling capacity. Each tube maintains its temperature uniformity advantage while the group of tubes collectively provides sufficient heat exchange area.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The solution transitions from a single-plane arrangement to a three-dimensional stacked configuration of multiple single-pass tubes. This dimensional change allows the system to accumulate sufficient heat exchange surface area vertically while each individual tube maintains its temperature uniformity advantage through the single-pass design.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Ease of manufacture

If conventional evaporator design is used, then manufacturing simplicity is maintained, but performance for heat exchange deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidheat exchange efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The evaporator is segmented into multiple standardized single-pass tubes that can be manufactured independently using conventional techniques. This segmentation allows each tube to be produced with simple, proven manufacturing methods while the overall system achieves superior heat exchange efficiency through the combined performance of multiple optimized tubes.

Inventive Principle:
Principle #1Segmentation

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 homogenizes the refrigerant fluid flow rate, improving heat exchange efficiency and reducing pressure drops within the evaporator, resulting in enhanced performance and comfort in vehicle air conditioning.

Implementation Method 1

cool an air flow circulating through said passages through the evaporator

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the low pressure refrigerant fluid leaving the expansion valve then passes through the evaporator, to be evaporated there

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3568656B1Evaporator, notably for a motor vehicle air conditioning circuit, and corresponding air conditioning circuit
Publication Date: 2021.05.12 VALEO SYST THERMIQUES SAS
  • EP3568656B1 patent drawingFigure 1~2
  • EP3568656B1 patent drawingFigure 3~4

AI summary

The invention relates to an evaporator (111), notably for a motor vehicle air conditioning circuit (100), comprising a stack of plates forming tubes (300) for the circulation of a refrigerant and between them delimiting air passages so as to cool a stream of air (250) circulating via said passages across the evaporator (111). According to the invention, at least one of said tubes (300) comprises a single flow path (315a, 315b, 315c) for said refrigerant between an inlet orifice (310) and an outlet orifice (320), said flow path (315a, 315b, 315c) being made up of a plurality of successive passes, said inlet orifice (310) of said at least one tube (300) being in fluidic communication with a refrigerant inlet port (210) of said evaporator (111), and said outlet orifice (320) of said at least one tube (300) being in fluidic communication with a refrigerant outlet port (220) of the separator (111).