Microchannel Heat Exchanger Multi-Circuit Layout for Lower Pressure Drop

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Solution Overview

Problem

Microchannel heat exchangers with a single refrigerant circuit experience high refrigerant side pressure drop and reduced heat transfer efficiency, particularly at high outdoor ambient conditions, compared to round tube plate fin heat exchangers.

Innovation Solution

Implementing multiple independent refrigerant circuits within the microchannel heat exchanger, where refrigerant flows through separate sets of microchannel tubes, allowing for multiple passes and combining the flows to reduce pressure drop and enhance heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single refrigerant circuit is used in a microchannel heat exchanger, then the device complexity is reduced, but the refrigerant side pressure drop increases and heat transfer efficiency decreases

Engineering Contradiction:

Improvecircuit configurationVSAvoidpressure drop

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The single refrigerant circuit is divided into multiple independent circuits (first circuit and second circuit), each with separate microchannel tubes. This segmentation reduces the refrigerant flow rate in each circuit, thereby reducing the pressure drop and improving heat transfer efficiency while maintaining manageable device complexity through modular circuit design.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a single refrigerant circuit is used in a microchannel heat exchanger, then the device complexity is reduced, but the heat transfer efficiency decreases

Engineering Contradiction:

Improvecircuit configurationVSAvoidheat transfer efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Object-generated harmful factors

If multiple circuit is implemented, then the refrigerant side pressure drop is reduced and heat transfer efficiency is improved, but the device complexity increases

Engineering Contradiction:

Improvepressure dropVSAvoidcircuit configuration

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The heat exchanger is divided into multiple independent circuits with separate microchannel tube sets, reducing pressure drop in each circuit while maintaining manageable complexity through modular design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple independent circuits are merged into a single heat exchanger unit with common headers and outlet, allowing parallel refrigerant flow paths that reduce pressure drop while consolidating the overall device structure to manage complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 multiple circuit design reduces refrigerant side pressure drop and improves heat transfer efficiency, making it comparable to or better than traditional round tube plate fin heat exchangers, especially under high ambient conditions.

Implementation Method 1

The refrigerant flows through the plurality of microchannel tubes, and the air flows over the plurality of microchannel tubes

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the air flows over the plurality of microchannel tubes

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

exchanges heat with a second fluid

Methodology Applied

Scientific EffectConduction (thermal): Conduction (thermal)

Data Source

PatentUS8695375B2Microchannel heat exchanger including multiple fluid circuits

Publication Date: 2014.04.15 CARRIER CORP

AI summary

A microchannel heat exchanger includes a plurality of microchannel tubes including a first set of microchannel tubes and a second set of microchannel tubes. A first circuit of the microchannel heat exchanger includes the first set of microchannel tubes, and a portion of a first fluid flows through the first set of microchannel tubes and exchanges heat with a second fluid. A second circuit of the microchannel heat exchanger includes the second set of microchannel tubes, and a reminder of the first fluid flows through the second set of microchannel tubes and exchanges heat with the second fluid. The first fluid from the first circuit and the first fluid from the second circuit combine into a common flow.