Microchannel Heat Exchanger Core Layout for Packaging Constraints

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Solution Overview

Problem

Microchannel heat exchangers face packaging constraints in heating and cooling systems, where inlet and outlet plumbing limits the volume allocation for the heat exchanger core, reducing the overall heat transfer capability due to unoccupied regions and restricted size and orientation.

Innovation Solution

A microchannel heat exchanger design featuring a primary and secondary core with interconnects and fins, allowing for a secondary core to occupy unoccupied regions and enabling bending into shapes like A-shape, M-shape, or V-shape to increase heat transfer surface area within a given volume, while maintaining efficient fluid distribution and flow characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If inlet and outlet plumbing is added to the heat exchanger, then fluid flow capability is improved, but volume allocation for the heat exchanger core is reduced

Engineering Contradiction:

Improvefluid flow capabilityVSAvoidvolume allocation for heat exchanger core

Core Design Contradiction:

ProductivityVSVolume of stationary object

Solution Approach 1:

The patent integrates the plumbing (inlet and outlet ports) directly within the header structure of the heat exchanger core. The headers serve dual functions as both structural components of the core and as fluid distribution manifolds, with ports embedded in the header faces. This nesting eliminates separate plumbing components and allows the plumbing volume to be contained within the overall heat exchanger envelope without reducing core volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If the heat exchanger core size is increased to improve heat transfer capability, then heat transfer performance is improved, but packaging constraints are violated

Engineering Contradiction:

Improveheat transfer capabilityVSAvoidheat exchanger core volume

Core Design Contradiction:

ProductivityVSVolume of moving object

Solution Approach 1:

The patent employs a compact, planar microchannel heat exchanger design where the core is arranged in a flattened, two-dimensional configuration rather than a traditional three-dimensional bulk structure. The microchannels are formed as thin, flat passages between plates or within a planar substrate, allowing high heat transfer surface area to be achieved within a reduced volume footprint that conforms to packaging constraints.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the geometric parameters of the heat exchanger core by using microscale channel dimensions (typically 0.5-5 mm hydraulic diameter) rather than conventional tube sizes. This parameter change increases the surface area to volume ratio, enabling high heat transfer capability within a compact core volume that fits packaging requirements.

Inventive Principle:

Principle #35Parameter changes

3Volume of stationary object

If unoccupied regions are eliminated to maximize volume utilization, then volume efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvevolume utilization efficiencyVSAvoidstructural complexity

Core Design Contradiction:

Volume of stationary objectVSDevice complexity

Solution Approach 1:

The header structure in the patent serves multiple functions simultaneously: it acts as a structural support element, a fluid distribution manifold with integrated ports, and a boundary definition for the heat exchanger core. This multi-functionality eliminates the need for separate end plates, manifolds, and port fittings, thereby eliminating unoccupied regions without significantly increasing structural complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This design enhances heat transfer efficiency by maximizing the heat transfer surface area within a compact volume, accommodating plumbing constraints and improving system performance by optimizing the placement of system components.

Implementation Method 1

Microchannel heat exchangers can offer improved heat transfer effectiveness relative to round tube and fin heat exchangers

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a first plurality of microchannel tubes having a first plurality of fluid passages extending therethrough and having a primary tube length L1, wherein the first plurality of microchannel tubes extend between the first header and the second header such that the first plurality of fluid passages are in fluid communication with the first collection volume and the second collection volume

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS11713928B2Microchannel heat exchanger having auxiliary headers and core

Publication Date: 2023.08.01 CARRIER CORP

AI summary

Disclosed is a microchannel heat exchanger comprising a primary core including a first header and a second header and a secondary core including a first auxiliary header and a second auxiliary header, further comprising a first header interconnect extending between the first header and the first auxiliary header and having a first interconnect fluid passage extending therethrough; and a second header interconnect extending between the second auxiliary header and the second header and having a second interconnect fluid passage extending therethrough.