Compressor Cooling Lubrication With Refrigerant-Oil Separation
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Solution Overview
Problem
Existing cooling systems for refrigerant compressors face challenges in providing reliable and cost-effective lubrication, especially at varying operational conditions, due to the poor lubrication characteristics of ultra-low viscous volatile fluids and the need for expensive, high-resistant bearings.
Innovation Solution
A cooling system that uses a mixture of refrigerant and lubrication oil with an oil separator reducing the refrigerant percentage to between 15% to 60% by weight, allowing a viscosity ratio greater than 1 for sustainable hydrodynamic lubrication, and incorporating ceramic and nitrided components to enhance bearing durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultra-low viscous volatile fluid is used as lubrication medium, then the bearing can be kept lubricated with a liquid film, but the lubrication characteristic becomes poor requiring expensive high-resistant bearings
Solution Approach 1:
A flow restriction element is introduced as an intermediary component between the lubrication medium supply and the bearing. This flow restriction maintains the fluid at least partly above the evaporating pressure, enabling sustained liquid lubrication film formation without requiring expensive high-resistant bearings
Solution Approach 2:
The pressure parameter of the lubrication medium is changed by using a flow restriction to maintain it above the evaporating pressure. This parameter change enables the ultra-low viscous volatile fluid to form a sustainable liquid lubrication film under bearing operating conditions
2Productivity
If refrigerant percentage in operating medium is increased, then the lubrication viscosity decreases, but the film thickness becomes insufficient
Solution Approach 1:
The refrigerant percentage in the operating medium is optimized within the range of 15-60% by weight. This parameter change balances the competing requirements of maintaining adequate lubrication viscosity while ensuring sufficient film thickness for reliable bearing operation
Solution Approach 2:
The system allows variable rotational speeds and dynamic operating conditions. The lubrication system adapts to changing operational requirements while maintaining reliable lubrication through the optimized refrigerant-oil mixture composition
3Use of energy by moving object
If bearing rotational speed is reduced for energy optimization, then the viscosity ratio decreases, but the lubrication effectiveness deteriorates
Solution Approach 1:
The operating medium composition is optimized with 15-60% refrigerant by weight to maintain adequate viscosity ratios even at reduced rotational speeds. This parameter change enables energy-optimized operation while preserving lubrication effectiveness
Solution Approach 2:
A composite operating medium consisting of refrigerant and lubrication oil is used. This composite material provides both the cooling function and the lubrication function, with the optimized composition ensuring sufficient viscosity and film formation across varying operational speeds
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 system achieves reliable and cost-effective lubrication across various operating states, prolonging bearing lifespan and reducing the demand on oil separators, while allowing for variable rotational speeds and energy-optimized operation.
Implementation Method 1
an oil separator reducing the refrigerant percentage to between 15% to 60% by weight
Implementation Method 2
the refrigerant is vaporized due to the bearing temperature
Implementation Method 3
a sufficiently formed sustainable hydrodynamic lubrication film is provided
Data Source
AI summary
A cooling system includes a refrigerant compressor and a first operating medium, which provides a mixture of refrigerant and lubrication oil. An oil separator reduces the percentage of the refrigerant in the operating medium to a value between 15% by weight and 60% by weight.