Accumulator Bypass Valve Control for Refrigerant and Oil Return
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air-conditioning apparatuses lack precise control over refrigerant flow rate and oil return to the compressor, leading to performance and reliability issues due to inadequate adjustment of valve openings based on operating states and outdoor conditions.
Innovation Solution
An air-conditioning apparatus with a refrigerant circuit, a bypass pipe, a flow control valve, and a control unit that adjusts the valve opening degree based on two-layer separation state and refrigerant temperature, ensuring accurate bypass flow rate control and appropriate oil return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a refrigerant container (accumulator) is installed at the suction side of the compressor to store excess refrigerant, then refrigerant insufficiency is prevented, but the apparatus cannot precisely control refrigerant flow rate and oil return based on operating conditions
Solution Approach 1:
The patent implements dynamic control of the oil return valve opening degree based on operating conditions (evaporating temperature, compressor operating frequency). The control unit adjusts the valve opening in real-time according to detected temperature and frequency signals, enabling the system to adaptively optimize refrigerant flow rate and oil return characteristics for different operating scenarios, thereby resolving the contradiction between reliable refrigerant storage and precise flow control.
2Reliability
If the accumulator stores a large amount of refrigerating machine oil, then oil return to the compressor is ensured, but the compressor may seize due to excessive oil accumulation
Solution Approach 1:
The patent controls the opening degree of the oil return valve as a variable parameter based on evaporating temperature and compressor operating frequency. By dynamically adjusting this parameter, the system regulates the rate of oil return to match actual operating conditions, preventing both insufficient oil return and excessive oil accumulation that could cause compressor seizure.
Solution Approach 2:
The control unit receives feedback signals from temperature detectors and operating frequency detectors, processes this information, and adjusts the oil return valve opening degree accordingly. This closed-loop feedback mechanism ensures that oil return is precisely controlled according to actual operating conditions, preventing harmful effects of excessive oil accumulation while ensuring adequate oil supply.
3Device complexity
If the opening degree of the oil return valve is fixed, then the structure is simple, but the refrigerant flow rate and oil return cannot be accurately controlled based on operating conditions
Solution Approach 1:
The patent transforms the fixed valve structure into a dynamically adjustable system where the oil return valve opening degree varies based on operating conditions. The control unit processes temperature and frequency signals to determine optimal opening degrees, achieving precise control of refrigerant flow rate and oil return while maintaining reasonable structural complexity through automated control.
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 enables high-accuracy two-layer separation state determination, preventing unnecessary liquid back and ensuring reliable oil return to the compressor, thus preventing compressor breakdown and maintaining high reliability and performance across varying conditions.
Implementation Method 1
At a specific temperature or higher, the density of the refrigerating machine oil used together with the refrigerant in the air-conditioning apparatus becomes lower than the density of the refrigerant, so that two-layer separation of the liquid refrigerant and the refrigerating machine oil occurs.
Data Source
AI summary
An air-conditioning apparatus is able to ensure an appropriate flow rate of refrigerant and an appropriate amount of oil returned to a compressor that match operation conditions regardless of an operating state of a refrigerant circuit and a change in an operation condition. The air-conditioning apparatus includes: a first detector configured to detect a refrigerant temperature within an accumulator; a storage unit configured to store information regarding a two-layer separation temperature of refrigerant and refrigerating machine oil; a determiner configured to compare the refrigerant temperature with the two-layer separation temperature and determine a two-layer separation state of the refrigerant and the refrigerating machine oil; a second detector configured to detect a state of the refrigerant sucked by the compressor; and a control unit configured to adjust an opening degree of a flow control valve on the basis of the two-layer separation state and a state of the sucked refrigerant.