Heat Exchanger Baffle Layout for Low-Pressure Refrigerant Flow

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Vapor compression systems face challenges in designing components compatible with environmentally-friendly refrigerants, particularly in maximizing efficiency using low pressure refrigerants, due to the 'submergence penalty' which affects heat transfer and increases operating costs.

Innovation Solution

A heat exchanger design with a trough and perforated baffle system that enhances refrigerant distribution over tube bundles, reducing pressure head and promoting uniform flow, thereby improving heat transfer and system efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional heat exchanger design is used with low pressure refrigerants, then the system can operate with environmentally-friendly refrigerants, but heat transfer efficiency deteriorates due to submergence penalty

Engineering Contradiction:

Improvesubmergence penaltyVSAvoidheat transfer efficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The heat exchanger is segmented into multiple zones with different baffle configurations. The first zone uses a standard baffle while subsequent zones use corrugated baffles with varying degrees of corrugation. This segmentation allows the refrigerant flow to be progressively enhanced as it moves through the heat exchanger, addressing the submergence penalty in different sections with appropriate levels of disruption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Corrugated baffles with curved, wave-like surfaces are used instead of flat baffles. The corrugations create turbulence by forcing the refrigerant to follow curved paths and creating eddies. This curvature-induced turbulence enhances heat transfer by disrupting the boundary layer and reducing the submergence penalty effect throughout the heat exchanger.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Loss of energy

If refrigerant flow is increased to overcome submergence penalty, then heat transfer improves, but pressure head increases and system complexity increases

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidpressure head requirements

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The corrugated baffles use curved geometries to generate turbulence without requiring increased flow rates. The wave-like corrugations create rotational flow patterns and eddies that enhance mixing and heat transfer while maintaining relatively low pressure heads. This allows improved heat transfer efficiency without proportionally increasing system complexity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The degree of corrugation varies dynamically across different zones of the heat exchanger. Earlier zones have lighter corrugations while later zones have more pronounced corrugations. This progressive dynamic adjustment optimizes turbulence generation at each stage of refrigerant flow, improving heat transfer efficiency while distributing pressure head requirements across multiple zones rather than requiring high pressure throughout.

Inventive Principle:

Principle #15Dynamics

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 design increases thermal energy transfer and reduces the submergence penalty, allowing for effective use of low pressure refrigerants and enhancing overall system efficiency.

Implementation Method 1

Vapor compression systems utilize a working fluid, typically referred to as a refrigerant that changes phases between vapor, liquid, and combinations thereof in response to being subjected to different temperatures and pressures

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

a heat exchanger disposed along the refrigerant loop and configured to place the refrigerant in thermal communication with a cooling fluid flowing through tubes of a tube bundle within the heat exchanger

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10088208B2Vapor compression system

Publication Date: 2018.10.02 TYCO FIRE & SECURITY GMBH

AI summary

Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system that includes a refrigerant loop, a compressor disposed along the refrigerant loop and configured to circulate refrigerant through the refrigerant loop, a heat exchanger disposed along the refrigerant loop and configured to place the refrigerant in thermal communication with a cooling fluid flowing through tubes of a tube bundle within the heat exchanger, an inlet of the heat exchanger configured to direct the refrigerant into the heat exchanger, a trough of the heat exchanger configured to receive the refrigerant from the inlet, and a perforated baffle of the heat exchanger disposed downstream of the trough and configured to direct the refrigerant from the trough over the tubes of the tube bundle.