Multi-Compressor Oil Level Control Using Separators and Return Valves
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Solution Overview
Problem
In multi-type air conditioners with inverter compressors, maintaining a constant oil level is challenging due to varying oil discharge rates across different operating modes, leading to potential compressor failure from oil shortages or efficiency deterioration from oversupply, which affects the overall performance and power consumption.
Innovation Solution
A method that includes a system of oil separators, return valves, and oil pumps connected to compressors to monitor and regulate the oil level, ensuring that oil is returned to compressors as needed, preventing both insufficient and excessive oil supply by using oil level sensors to control the oil return valves and pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple inverter compressors are operated together with different operating modes, then the air conditioning load can be met and cooling/heating performance is improved, but the oil discharge rates differ causing oil level imbalance between compressors
Solution Approach 1:
The system uses oil level sensors to continuously monitor the oil level in each compressor's crankcase and provides feedback to the control unit. The control unit adjusts the operation of oil return valves and oil pumps based on this feedback to maintain balanced oil levels across all compressors, resolving the oil level imbalance caused by different operating modes.
Solution Approach 2:
Oil separators are introduced as intermediary devices between the compressors and the refrigerant circulation system. These separators capture oil from the refrigerant discharge and facilitate controlled oil return to specific compressors, enabling precise oil level management while allowing multiple compressors to operate simultaneously with different loads.
2Reliability
If oil discharge rate is increased to prevent oil shortage, then compressor lubrication is improved, but excessive oil may accumulate causing efficiency deterioration
Solution Approach 1:
The system dynamically adjusts the oil return mechanism based on real-time oil level conditions. Oil return valves are opened or closed, and oil pumps are activated or deactivated, to match the actual oil discharge rates of operating compressors. This dynamic control ensures adequate lubrication without excessive oil accumulation that would increase motor power consumption.
Solution Approach 2:
The control unit monitors oil level parameters in each compressor and changes the operational parameters of oil return valves and pumps accordingly. By adjusting these parameters based on measured oil levels, the system maintains optimal lubrication while preventing oil excess that would deteriorate compressor efficiency and increase energy consumption.
3Reliability
If oil level is maintained at high level to ensure sufficient lubrication, then compressor reliability is improved, but oil circulation system complexity increases
Solution Approach 1:
The oil circulation system is segmented into individual control zones for each compressor, with dedicated oil level sensors, oil return valves, and oil pumps for each compressor. This segmentation allows independent oil level management for each compressor, ensuring sufficient lubrication without requiring a single complex centralized oil circulation system.
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 maintains a consistent oil level across multiple compressors, preventing failures and optimizing energy efficiency by ensuring the right amount of oil is available for lubrication and cooling, thereby enhancing the operational reliability and efficiency of the air conditioning system.
Implementation Method 1
a plurality of oil separators (171) connected respectively to the plurality of compressors (110) to separate oil from the compressed refrigerant discharged from the compressors (110)
Data Source
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AI summary
Disclosed is an air conditioner in which a plurality of compressors (110) retains a constant oil level. The air conditioner includes a plurality of compressors (110) configured to compress a refrigerant, a plurality of oil separators (171) connected respectively to the plurality of compressors and serving to separate oil contained in the refrigerant compressed in and discharged from the compressors, a plurality of oil return pipes (177) configured to allow the oil separated in the plurality of oil separators to be returned into the plurality of compressors, a plurality of oil return valves (176) installed respectively to the plurality of oil return pipes to open or close the plurality of oil return pipes respectively, and a resistor (175) configured to connect the plurality of oil return pipes to each other.