VFD Heat Sink Refrigerant Circuit for Low Pressure Drop Cooling

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Solution Overview

Problem

Existing cooling systems for high-power variable frequency drives (VFDs) face challenges in achieving efficient two-phase flow distribution and high heat dissipation while maintaining a compact heat sink design and low pressure drop.

Innovation Solution

A refrigerant circuit with machined channels of predefined profiles, extending between inlet and outlet conduits, is positioned in thermal contact with heat generating components, allowing controlled flow of cooling fluid to absorb and dissipate heat efficiently, and a controller monitors temperature to manage the flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional cooling systems are used for high-power VFDs, then heat dissipation can be achieved, but the system size becomes large and pressure drop increases

Engineering Contradiction:
Improveheat dissipation rateVSAvoidheat sink size
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The cooling system is divided into multiple independent channels with different configurations (single-pass, multi-pass, serpentine patterns) that can be selectively used based on heat load requirements. This segmentation allows the system to achieve high heat dissipation rates without requiring a uniformly large heat sink, as only the necessary channel configurations are activated or dimensioned for each specific cooling demand.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from conventional two-dimensional channel layouts to three-dimensional multi-pass channel configurations within the heat sink. By utilizing vertical and horizontal passes through the heat sink body, the system increases the effective heat transfer surface area and cooling efficiency without proportionally increasing the external dimensions of the heat sink, thereby achieving high heat dissipation in a compact form factor.

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

2Productivity

If conventional cooling systems are used for high-power VFDs, then heat dissipation can be achieved, but pressure drop becomes high

Engineering Contradiction:
Improveheat dissipation rateVSAvoidpressure drop
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The system incorporates variable frequency drives that dynamically adjust the flow rate of cooling fluid through different channel configurations based on real-time heat load conditions. This dynamic control allows the system to optimize the balance between heat dissipation rate and pressure drop, activating high-performance channel configurations only when necessary and using lower-flow configurations during normal operation to minimize pressure drop.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs multiple channel configurations with varying hydraulic diameters, lengths, and flow path complexities that can be selectively activated. By changing which channel configuration is active based on operating conditions, the system can adjust the pressure drop characteristics while maintaining adequate heat dissipation performance, thus avoiding consistently high pressure drop across all operating conditions.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If two-phase flow distribution is improved, then heat dissipation efficiency increases, but system complexity increases

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidflow distribution system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The two-phase flow distribution system is segmented into multiple independent channel groups, each with its own flow distribution characteristics. This segmentation allows each channel configuration to be optimized for specific heat load conditions without requiring a completely complex distribution system, as the modular nature of segmented channels simplifies the overall flow distribution architecture while maintaining high heat dissipation efficiency.

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

This configuration enables efficient heat dissipation and reduced pressure drop, maintaining a compact design, effectively addressing the limitations of existing systems.

Implementation Method 1

the channels are adapted to allow flow of a cooling fluid therethrough to facilitate dissipation of heat generated by the VFD

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the cooling fluid while flowing through the one or more channels absorbs the heat dissipated by the VFD

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentEP4391758A1Refrigerant circuit and cooling system for a VFD heat sink
Publication Date: 2024.06.26 CARRIER CORP
  • EP4391758A1 patent drawingFigure 1A~1B
  • EP4391758A1 patent drawingFigure 1C~1D
  • EP4391758A1 patent drawingFigure 1E~1F

AI summary

A refrigerant circuit for a variable frequency drive (VFD) heat sink is disclosed. The refrigerant circuit comprises one or more channels machined in a predefined profile and positioned in thermal contact with a VFD. The channels are adapted to allow the flow of a cooling fluid therethrough to facilitate the dissipation of heat generated by the VFD. The channels are machined in the predefined profile such that each of the machined flow path comprises a predefined number of turns or a predefined number of passes.