Evaporator in a refrigerant circuit c

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Solution Overview

Problem

Existing evaporators in refrigerant circuits, such as those in vehicle air conditioning systems, face challenges with complex process technology and structurally complicated separator geometries due to the use of centrifugal force for phase separation, which complicates operation and design.

Innovation Solution

A separator with a distributor tube having a reduced cross section and discharge openings that interact with a deflector wall within the evaporator's inlet chamber, where the two-phase refrigerant mixture flows, allowing for phase separation through a refrigerant jet contacting the deflector wall, and micro-channels are configured to direct vapour and liquid phases separately, reducing pressure loss and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If centrifugal force is used for phase separation in the evaporator inlet chamber, then phase separation can be achieved, but the process technology becomes complex and the separator geometry becomes structurally complicated

Engineering Contradiction:

Improvephase separationVSAvoidseparator geometry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The separator is divided into multiple distributor tubes, each with multiple discharge openings. This segmentation allows the phase separation function to be distributed across multiple simple components rather than requiring a single complex centrifugal separator structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using centrifugal force to separate phases (complex approach), the invention uses a simple jet impact mechanism where refrigerant flows directly from discharge openings and contacts the deflector wall (simple approach), inverting the conventional separation methodology.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If a complex separator geometry is used for phase separation, then separation can be achieved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvephase separationVSAvoidseparator structure

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The separator consists of multiple identical distributor tubes with discharge openings, which can be manufactured using standard machining processes. This segmented design is much easier to manufacture than a single complex centrifugal separator geometry.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separator uses multiple copies of the same simple distributor tube structure. Each distributor tube is an identical copy with the same discharge openings and geometry, simplifying manufacturing through repetition of a standard component.

Inventive Principle:

Principle #26Copying

3Productivity

If micro-channels are used in evaporator tubes, then heat exchange efficiency is improved, but pressure loss increases due to complex flow paths

Engineering Contradiction:

Improveheat exchange efficiencyVSAvoidpressure loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The deflector wall is positioned at specific locations relative to the discharge openings to create optimal local flow conditions. This local optimization directs the refrigerant jet effectively without creating excessive pressure loss throughout the entire micro-channel system.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the flow parameters by using a jet impact mechanism before the refrigerant enters the micro-channels. This pre-conditioning of the flow reduces pressure losses in subsequent micro-channel flow paths while maintaining heat exchange efficiency.

Inventive Principle:

Principle #35Parameter changes

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 simplifies the process technology and structural configuration of the evaporator, reducing pressure loss and improving efficiency by effectively separating phases, allowing for a more straightforward design and operation while maintaining high performance.

Implementation Method 1

A refrigerant jet exits during operation from the discharge opening and comes into contact with the deflector wall, at which a phase separation takes place

Methodology Applied

Scientific EffectPhase separation: Centrifugal Separation

Implementation Method 2

The refrigerant liquid phase in the evaporator is therefore evaporated into the vapour phase with absorption of thermal energy from the air flow

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

The evaporator (for example, a cross-counterflow heat exchanger) is flowed through by way of an air flow to be cooled which is guided into the vehicle interior compartment

Methodology Applied

Scientific EffectHeat absorption: Heat Exchanger

Data Source

PatentUS10760833B2Evaporator in a refrigerant circuit c

Publication Date: 2020.09.01 AUDI AG

AI summary

An evaporator in a refrigerant circuit, having a bottom-side inlet chamber which is connected in flow terms to an evaporator outlet side via evaporator tubes, a separator being integrated into the evaporator inlet chamber, in which separator a refrigerant which is expanded in an expansion member is divided as a two-phase liquid/vapour mixture into a vapour phase and into a liquid phase which is separate therefrom, the vapour phase being conducted via a bypass line to the evaporator outlet side, and the liquid phase being conducted counter to the direction of gravity into the evaporator tubes. The separator has a distributor tube which extends in the inlet chamber in the evaporator transverse direction.