Chiller motor with cooling flow path
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Solution Overview
Problem
The use of low-pressure refrigerant in motor cooling systems for centrifugal compressors results in high volumetric flow rates, leading to increased pressure drop and restricted flow rates, which can cause motor temperatures to exceed safe limits, degrading the performance of chiller assemblies.
Innovation Solution
A cooling system with a housing and fluid directing features that create split serpentine-shaped cooling fluid paths to enhance heat transfer and reduce pressure drop, ensuring consistent temperature distribution across the motor, utilizing a housing with multiple fluid directing protrusions to define separate cooling fluid paths for improved refrigerant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low-pressure refrigerant is used in motor cooling system, then cheaper and simpler induction motors can be used, but volumetric flow rate increases leading to high pressure drop and restricted flow rates
Solution Approach 1:
The cooling system is segmented into multiple independent cooling channels (first cooling fluid path and second cooling fluid path) that are distributed around the motor. This segmentation increases the total flow area and reduces pressure drop by allowing parallel flow paths, while each individual channel maintains adequate cooling effectiveness.
Solution Approach 2:
The cooling fluid paths are arranged in a serpentine configuration that extends in multiple dimensions around the motor housing. This multi-dimensional arrangement maximizes the use of available space, increases effective flow area, and reduces pressure drop by creating multiple flow routes rather than a single linear path.
2Ease of manufacture
If low-pressure refrigerant is used in motor cooling system, then simpler motors can be used, but flow rate restriction decreases cooling effectiveness
Solution Approach 1:
The cooling system uses multiple segmented cooling channels distributed around the motor, ensuring that cooling effectiveness is maintained across the entire motor surface. Each channel contributes to overall cooling, providing redundancy and reliability even with simpler motor construction.
Solution Approach 2:
Different portions of the motor are served by dedicated cooling channels (first portion and second portion), allowing localized optimization of cooling flow. The serpentine path ensures each region receives adequate cooling fluid flow, maintaining local cooling effectiveness throughout the motor assembly.
3Quantity of substance
If higher volumetric flow rate is required for LP refrigerant cooling, then cooling capacity increases, but pressure drop increases and flow rate becomes restricted
Solution Approach 1:
The high volumetric flow rate requirement is met by segmenting the cooling system into multiple parallel channels. Each channel carries a portion of the total flow, reducing the flow velocity and pressure drop in each individual channel while maintaining the total cooling capacity through the combined flow of all channels.
Solution Approach 2:
The serpentine cooling paths are configured to utilize three-dimensional space around the motor, creating multiple flow dimensions. This arrangement increases the effective flow area and provides multiple flow routes, reducing pressure drop while accommodating the high volumetric flow rate requirements of LP refrigerant cooling.
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 split serpentine cooling system effectively maintains motor temperatures within efficient ranges by increasing the cooling fluid flow area and reducing pressure drop, thereby enhancing the overall performance of the chiller assembly.
Implementation Method 1
The cooling system includes a housing with a cavity enclosing the motor and defining a central axis... a fluid circuit configured to circulate a cooling fluid between the housing and the motor
Implementation Method 2
a vapor compression system includes a centrifugal compressor directly driven by an induction motor... configured to circulate a refrigerant
Data Source
AI summary
A cooling system for a motor to power a compressor in a vapor compression system is provided. The cooling system includes a housing with a cavity enclosing the motor and defining a central axis and fluid directing features extending into the cavity and oriented parallel to the central axis. The cooling system further includes a fluid circuit configured to circulate a cooling fluid between the housing and the motor. The fluid circuit includes a first cooling fluid path defined by directing features that cause a first portion of cooling fluid to travel around a first portion of the motor and a second cooling fluid path defined by fluid directing features that cause a second portion of cooling fluid to travel around a second portion of the motor. The second portion of the motor is located opposite the first portion.