Hybrid Outdoor AC Compressor Pressure Balancing for Lubrication Reliability
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Solution Overview
Problem
In hybrid outdoor air conditioner units with both engine-driven and electrically driven compressors, the operational reliability of the electrically driven compressor with a lower capacity is reduced due to increased discharge pressure when both compressors operate simultaneously, leading to inadequate lubrication of sliding components.
Innovation Solution
The discharge pressure of the electrically driven compressor is maintained lower than that of the engine-driven compressor by adjusting the opening degree of the expansion valve, and the refrigerant flow is managed through a combined suction pipe and heat exchangers to prevent excessive pressure increase, ensuring proper lubrication and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both compressors are simultaneously operated, then the air conditioning load can be met across different operating conditions, but the discharge pressure of the electrically driven compressor increases excessively, reducing its operational reliability
Solution Approach 1:
The patent introduces a flow control valve as an intermediary device in the refrigerant circuit to regulate and balance the refrigerant flow distribution between the two compressors. This mediator prevents the smaller electrically driven compressor from being subjected to excessive discharge pressure by controlling the refrigerant flow it receives, thereby resolving the contradiction between system adaptability and compressor reliability
Solution Approach 2:
The patent changes the operating parameters of the refrigerant circuit by adjusting the flow control valve to modify the refrigerant flow rate and pressure distribution. By dynamically adjusting these parameters, the system ensures that each compressor operates within its optimal pressure range, preventing excessive discharge pressure in the electrically driven compressor while maintaining the ability to meet various air conditioning loads
2Loss of energy
If the electrically driven compressor operates at low frequency, then energy consumption is reduced, but the discharge pressure increases causing inadequate lubrication of sliding components
Solution Approach 1:
The flow control valve acts as a mediator that decouples the relationship between compressor operating frequency and discharge pressure. By regulating refrigerant flow independently of compressor speed, it maintains adequate pressure for lubrication even when the electrically driven compressor operates at low frequency, thus reducing energy consumption without compromising component lubrication
Solution Approach 2:
The system applies preliminary anti-action by using the flow control valve to preemptively prevent excessive pressure buildup in the refrigerant circuit before it can harm the electrically driven compressor. This anticipatory control ensures that even at low operating frequencies, the discharge pressure remains within safe limits that allow proper lubrication formation
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 approach prevents excessive discharge pressure in the electrically driven compressor, enhancing its operational reliability and efficiency by maintaining optimal pressure differences and lubrication conditions, even at low operation frequencies.
Implementation Method 1
The discharge pressure of the electrically driven compressor is prevented from being increased to a discharge pressure of the engine-driven compressor by adjusting the opening degree of the expansion valve
Implementation Method 2
the refrigerant flow is managed through a combined suction pipe and heat exchangers to prevent excessive pressure increase
Data Source
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AI summary
In a cooling operation, a first four-way valve (117) and a second four-way valve (118) each perform a switching operation in such a manner that a gas-pipe connection port (180) is coupled to a suction pipe of a first compressor (112) and a suction pipe of a second compressor (113), and a liquid-pipe connection port (190) is coupled to a discharge pipe of the first compressor (112) via the first outdoor heat exchanger (120) and the first four-way valve (117) and is coupled to a discharge pipe of the second compressor (113) via a second outdoor heat exchanger (121) and the second four-way valve (118).