Oil-free phase separating compressor
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Solution Overview
Problem
Existing compressors in HVACR systems face challenges in efficiently directing and separating working fluids, particularly in oil-free configurations, which can lead to reduced efficiency and increased risk of mechanical damage due to lack of lubrication and heat management.
Innovation Solution
The implementation of an oil-free scroll compressor with a liquid-vapor separation volume within the compressor housing, which separates mixed-phase working fluid into liquid and gaseous components, supplies the liquid working fluid to lubricate bearings, and directs the gaseous working fluid into compression pockets, enhancing efficiency and reducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an oil-free compressor configuration is used, then the compressor avoids oil contamination and is suitable for certain applications, but the bearings lack lubrication which reduces reliability and increases mechanical damage risk
Solution Approach 1:
The compressor uses its own working fluid (liquid refrigerant) to lubricate the bearings, eliminating the need for external oil systems. The liquid working fluid is diverted from the main compression cycle and routed through bearing lubrication passages, allowing the system to self-lubricate without oil contamination.
Solution Approach 2:
The system changes the state and function of the working fluid by diverting liquid refrigerant from the compression cycle to serve as a lubricant. This parameter change allows the same fluid to perform multiple functions: compression medium and lubricant, without requiring separate oil systems.
2Reliability
If liquid working fluid is supplied to bearings for lubrication, then reliability improves, but the complexity of fluid distribution system increases
Solution Approach 1:
The liquid working fluid serves multiple functions within the compressor system: it acts as the compression medium in the cylinders and simultaneously functions as a lubricant for the bearings. This multi-functionality reduces the need for separate lubrication systems and simplifies the overall fluid distribution architecture.
Solution Approach 2:
The lubrication system is merged with the refrigerant circulation system. Instead of having separate oil pumps and distribution channels, the liquid refrigerant flow paths are integrated to also supply bearing lubrication, combining two previously separate functions into one unified system.
3Productivity
If mixed phase working fluid is not separated, then the system is simpler, but compression efficiency decreases and mechanical stress increases
Solution Approach 1:
The mixed phase working fluid is segmented into its liquid and gaseous components through separation chambers before entering the compression cylinders. This segmentation allows the liquid portion to be used for lubrication while the gaseous portion undergoes compression, optimizing both lubrication and compression functions.
Solution Approach 2:
The working fluid is preliminarily separated into liquid and vapor phases before compression begins. This preliminary separation ensures that only appropriate phases enter the compression chambers, preventing liquid slugging and improving compression efficiency while allowing liquid to be available for bearing lubrication.
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 solution enables efficient separation and utilization of working fluids, improving the compressor's efficiency and extending its operational lifespan by providing lubrication and cooling to mechanical components.
Implementation Method 1
The liquid-vapor separation volume configured to separate a mixed phase of working fluid into liquid working fluid and gaseous working fluid
Implementation Method 2
The liquid working fluid is supplied to the bearing
Implementation Method 3
Rotation of the crankshaft is configured to drive the compression mechanism to provide compression
Data Source
AI summary
An oil-free compressor includes a compressor housing with a suction inlet and a discharge outlet, a compression mechanism and a liquid-vapor separation volume disposed within the compressor housing, a crankshaft. The compression mechanism has an inlet fluidly connected to the suction inlet and a discharge volume fluidly connected to the discharge outlet. The crankshaft is engaged with the compression mechanism. The liquid-vapor separation volume is configured to separate a mixed phase of working fluid into liquid working fluid and gaseous working fluid. The liquid working fluid is supplied to the bearing. A heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a refrigerant circuit with an oil-free compressor, a condenser, one or more expanders, and an evaporator.