Variable Volume Ratio Valve Control to Limit Switching Wear
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Solution Overview
Problem
Variable volume ratio compressors face inefficiencies under partial load conditions due to improper selection of volume ratios, leading to excessive wear from high-frequency switching, especially when operating close to switching conditions.
Innovation Solution
A controller system that adjusts the compressor's volume ratio based on suction density and speed, using sensors to determine a switching parameter and implementing delay periods to reduce frequent changes, thereby optimizing compressor performance and reducing wear on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated switching of volume ratios is implemented to improve compressor efficiency under partial load conditions, then compressor efficiency is improved, but high-frequency switching occurs causing excessive wear on variable volume ratio system components
Solution Approach 1:
The patent introduces delay periods between volume ratio switching operations to prevent high-frequency switching. The controller is configured to wait for a specified delay period after a volume ratio change before allowing another change, thereby reducing wear on components while still enabling efficiency improvements through volume ratio adjustment under partial load conditions
Solution Approach 2:
The system continuously monitors operating conditions and uses feedback control to determine when volume ratio switching is appropriate. The controller adjusts the volume ratio based on real-time compressor operating parameters, implementing switching only when efficiency benefits warrant the operation, thus avoiding unnecessary frequent switching
2Productivity
If volume ratio is adjusted frequently to match changing operating conditions, then compressor efficiency is improved, but excessive wear occurs on variable volume ratio system components
Solution Approach 1:
The patent implements delay periods that create intentional time intervals between volume ratio switching operations. This periodic restriction prevents excessive switching frequency, thereby extending the service life of moving components such as the variable volume ratio mechanism while still allowing efficiency optimizations when genuinely needed
3Productivity
If volume ratio switching is implemented without delay periods, then compressor efficiency can be optimized, but high-frequency switching occurs creating additional wear
Solution Approach 1:
The patent introduces mandatory delay periods between volume ratio switching operations to eliminate high-frequency switching. The controller is configured to enforce these time intervals, thereby reducing harmful wear effects on components while preserving the ability to optimize compressor efficiency through deliberate volume ratio adjustments
Data Source
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AI summary
Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.