Compressor Suction Injection for Stable R32 Heating Operation
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Solution Overview
Problem
Existing air conditioning systems face challenges with high compressor discharge temperatures during heating operations, especially with refrigerants like R32, leading to reduced stability and efficiency, and struggle with flow changes between cooling and heating modes.
Innovation Solution
The air conditioning apparatus incorporates a compressor with a suction injection system, including a suction injection pipe and expansion devices to moderate refrigerant temperature, allowing for stable operation across different modes by injecting refrigerant into the compressor's suction side, thereby controlling the discharge temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-pressure liquid refrigerant is injected into the compressor during heating operation, then the discharge temperature of the compressor is lowered and operating stability is improved, but the system requires additional injection components and complex refrigerant flow control
Solution Approach 1:
The patent uses an accumulator as an intermediary component to store high-pressure liquid refrigerant, which is then injected into the compressor suction side through a suction injection pipe. This intermediary approach allows controlled injection without directly connecting the high-pressure line to the compressor, reducing system complexity while maintaining reliability.
Solution Approach 2:
The accumulator pre-stores high-pressure liquid refrigerant before injection, preparing the refrigerant in advance for injection into the compressor. This preliminary action ensures that the refrigerant is ready for injection when needed, lowering discharge temperature and improving operating stability without requiring complex real-time high-pressure control.
2Adaptability or versatility
If the refrigerant flow is changed to switch between cooling and heating operations, then the air conditioning apparatus can adapt to different operating modes, but the discharge temperature of the compressor becomes unstable and may become too high
Solution Approach 1:
The patent implements dynamic refrigerant flow control using flow switching devices that can redirect refrigerant flow between cooling and heating modes. During heating operation, the system dynamically activates the suction injection mechanism to lower discharge temperature, while during cooling operation, the injection is deactivated. This dynamic adaptation maintains temperature stability across different operating modes.
Solution Approach 2:
The system changes the refrigerant injection parameter based on operating mode. During heating operation, high-pressure liquid refrigerant is injected into the compressor suction side to lower discharge temperature. During cooling operation, injection is stopped or reduced. This parameter change allows the system to adapt to different modes while maintaining stable discharge temperature.
3Adaptability or versatility
If multiple expansion devices and flow switching devices are added to enable cooling and heating mixed operation, then the system versatility is improved, but the device complexity and refrigerant flow control difficulty increase
Solution Approach 1:
The accumulator serves multiple functions: it stores excess refrigerant, provides high-pressure liquid refrigerant for injection during heating operation, and acts as a buffer to stabilize refrigerant flow. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall system complexity while maintaining mixed operation capability.
Solution Approach 2:
The patent segments the refrigerant flow control into distinct functional sections: the accumulator for refrigerant storage and pressure regulation, the suction injection pipe for targeted injection, and flow switching devices for mode selection. This segmentation allows each component to perform its specific function efficiently, reducing overall control difficulty while maintaining versatility.
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 effectively reduces compressor discharge temperature, enhancing operating stability and versatility across cooling, heating, and mixed operation modes, regardless of refrigerant flow changes, and improves system efficiency with refrigerants like R32.
Implementation Method 1
a third expansion device which generates a medium pressure smaller than the high pressure and larger than the low pressure during the heating operation in a channel of refrigerant from the at least one second heat exchanger to the first heat exchanger
Implementation Method 2
a suction injection pipe for externally introducing refrigerant in a liquid or a two-phase state into a channel between the compressor and the accumulator
Implementation Method 3
a compressor including a compression chamber inside a hermetically sealed container
Implementation Method 4
a first heat exchanger, at least one first expansion device, and at least one second heat exchanger are connected by refrigerant pipes to form a circuit constituting a refrigeration cycle
Data Source
AI summary
A channel on an upstream side of a third expansion device and a channel on an upstream side of a second expansion device are connected during a heating operation, and medium pressure refrigerant generated by the third expansion device during the heating operation is introduced on a suction side of a compressor via the second expansion device and a suction injection pipe.