Compressor Oil Sump Pressure Reduction for Lubricity Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In refrigeration systems and organic Rankine cycle systems, the absorption of refrigerant into lubricating oil reduces oil viscosity and lubricity, leading to potential mechanical failures and inefficiencies, particularly at elevated temperatures common in heat pump applications.
Innovation Solution
A pressure reducing device is introduced between the oil sump and the low-pressure side of the refrigerant system to lower the refrigerant pressure in the oil sump and motor housing, reducing refrigerant dilution in the oil and maintaining lower oil temperatures, thereby enhancing oil viscosity and lubricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If refrigerant pressure in the oil sump is reduced, then refrigerant dilution in the oil is reduced and oil viscosity is improved, but the cooling effect on the motor is reduced
Solution Approach 1:
The system is divided into two separate pressure zones: the oil sump operates at reduced pressure to minimize refrigerant dilution and maintain oil viscosity, while the motor housing maintains higher pressure to ensure adequate motor cooling. This segmentation allows each subsystem to operate under optimal pressure conditions independently.
Solution Approach 2:
A pressure control valve is introduced as an intermediary device between the oil sump and the motor housing to regulate and maintain different pressure levels in these two zones. The valve acts as a mediator that allows the system to simultaneously achieve both reduced refrigerant dilution in the oil and adequate motor cooling.
2Adaptability or versatility
If the compressor is designed for high temperature heat pump applications, then the operational range is extended, but refrigerant absorption into lubricating oil increases and reduces lubricity
Solution Approach 1:
The system changes the pressure parameter in the oil sump by reducing it below atmospheric pressure. This parameter change reduces the partial pressure of refrigerant in the oil sump, thereby minimizing refrigerant absorption into the lubricating oil even when operating at high temperatures. This allows the compressor to maintain reliable lubrication across an extended operational range including high temperature heat pump applications.
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 reduces the risk of mechanical failures, improves oil viscosity and lubricity, and extends the operational range of standard compressor systems to higher temperature heat pump applications, while also providing effective motor cooling.
Implementation Method 1
A pressure reducing device is introduced between the oil sump and the low-pressure side of the refrigerant system to lower the refrigerant pressure in the oil sump
Implementation Method 2
The motor operates in an atmosphere of refrigerant, the refrigerant surrounding and cooling the motor
Data Source
AI summary
A system for reducing the refrigerant pressure in an oil sump (10) or in a cavity (352) of a housing. The invention is particularly useful for reducing pressure in a compressor (23) for heat pump applications that has been validated for water chiller operations or in turbine and generator systems in ORC systems generating electricity using refrigerant, the ORC systems essentially being a heat pump application operating in reverse. An auxiliary compressor (509), an auxiliary condenser (709) or an ejector pump (609) may be used to reduce pressure in the oil sump (10), to separate refrigerant from oil. The auxiliary compressor (509), the auxiliary condenser (709) or the ejector pump (609) may also be used to reduce the pressure of refrigerant in the housing of a compressor in heat pump applications at temperatures and pressures at which the compressor was validated for water chiller applications and of the turbine and generator in ORC applications.