Lubricant blends to reduce refrigerant solubility
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Solution Overview
Problem
In vapor compression systems, such as HVACR systems, the interaction between new refrigerants and lubricants can lead to changes in solubility and viscosity, requiring different lubricants to maintain optimal performance, which can increase power consumption and system costs due to the need for additional hardware and restricted operating maps.
Innovation Solution
A lubricant blend comprising a mixture of two or more lubricants, where the first lubricant is present at a higher weight percentage and has higher viscosity than the second lubricant, is used to balance solubility and viscosity, reducing refrigerant solubility and maintaining miscibility within a desired operating range, thereby avoiding the need for additional hardware and optimizing system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a higher viscosity lubricant is selected to compensate for lubricant viscosity reduction due to higher refrigerant solubility, then bearing lubrication requirements are met, but power consumption increases and system efficiency decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricant by blending different types of lubricants (e.g., POE with PAG or ester with mineral oil) to achieve a blend that has lower refrigerant solubility than single lubricants. This parameter change in composition allows the system to use lower viscosity lubricants while maintaining adequate lubrication, thereby reducing power consumption without compromising bearing reliability
Solution Approach 2:
The patent applies composite lubricant blends combining two or more different lubricant types (such as POE/PAG blends, POE/ester blends, or mineral oil/ester blends) to create a material with superior properties. The composite blend reduces refrigerant solubility compared to individual lubricants, enabling lower viscosity operation while maintaining film thickness requirements, thus resolving the contradiction between reliability and energy consumption
2Reliability
If additional hardware (lubricant separator and/or lubricant heater) is added to the system to handle refrigerant-lubricant interactions, then system performance is maintained, but manufacturing cost increases and component reliability concerns arise
Solution Approach 1:
The patent extracts and eliminates the need for additional hardware components (lubricant separators and heaters) by using specially formulated lubricant blends that inherently resist refrigerant dissolution. The blend composition is selected to maintain miscibility and viscosity across the operating range without requiring external intervention, thereby simplifying the system while maintaining performance
Solution Approach 2:
The lubricant blend is designed to self-regulate its properties across varying operating conditions. The blend maintains adequate viscosity and miscibility without external heating or separation equipment, allowing the lubrication system to serve itself across the operating map without additional active components, thus reducing device complexity while maintaining reliability
3Reliability
If the system operating map is restricted due to refrigerant-lubricant interactions, then bearing lubrication requirements are met, but product sales are limited due to inability to operate under customer-specified conditions
Solution Approach 1:
The patent employs dynamic lubricant blends that adapt to varying operating conditions. The blend composition is selected to maintain miscibility and viscosity across a wide temperature and pressure range, allowing the system to operate dynamically under different customer-specified conditions without restricting the operating map while still meeting bearing lubrication requirements
Solution Approach 2:
The lubricant blend is designed with universal compatibility across diverse operating conditions and refrigerant types. The blend maintains adequate lubrication properties whether the system operates at high or low temperatures, high or low speeds, making it versatile for different customer applications and expanding the operating map rather than restricting it
Data Source
AI summary
Compositions, methods, systems, and applications herein are directed to lubricant blends that balance solubility and viscosity of a refrigerant, where in some cases the lubricant blends herein help reduce solubility of a refrigerant. A lubricant blend includes a mixture of two or more different types of lubricants to reduce refrigerant solubility.