Air-conditioning apparatus with regulation of injection flow rate
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Solution Overview
Problem
Air-conditioning systems using refrigerants like R32 face issues with excessively high discharge temperatures during heating operations, leading to refrigerant and oil deterioration, and existing solutions are not effective in reducing these temperatures or supporting mixed cooling and heating operations without specialized indoor units.
Innovation Solution
The system incorporates a refrigeration cycle with a compressor, heat exchangers, and expansion devices, including a suction-injection pipe to introduce refrigerant into the compressor's suction side, and a controller to regulate the suction-injection flow rate, allowing for safe operation and reduced discharge temperatures regardless of the operation mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If R32 refrigerant is used in heating operation, then cooling performance is improved, but discharge temperature becomes excessively high causing refrigerant and oil deterioration
Solution Approach 1:
The system performs preliminary cooling of the refrigerant by introducing it into the suction side of the compressor before compression occurs. This pre-cooling action prevents excessive discharge temperature by ensuring the refrigerant enters the compressor at a lower temperature, thereby avoiding refrigerant and oil deterioration while maintaining cooling performance.
Solution Approach 2:
A liquid refrigerant is introduced as an intermediary substance into the suction side of the compressor to cool the refrigerant before compression. This intermediary refrigerant acts as a cooling medium that absorbs excess heat, thereby reducing discharge temperature without affecting the primary cooling function.
2Adaptability or versatility
If check valves are arranged in parallel with expansion devices to enable suction-injection, then heating operation is improved, but specialized indoor units are required increasing device complexity
Solution Approach 1:
The outdoor unit is designed with multi-functionality to perform both cooling and heating operations without requiring specialized indoor units. The outdoor unit incorporates a suction-injection mechanism that can operate in both cooling and heating modes, making the system universal and adaptable to different operational requirements while maintaining standard indoor unit compatibility.
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 configuration ensures safe operation and extends the service life of the air-conditioning system by preventing refrigerant and oil deterioration, while enabling flexible switching between cooling and heating modes without the need for specialized indoor units.
Implementation Method 1
a suction-injection pipe configured to introduce, into a suction side of the compressor, a refrigerant in a liquid or two-phase state
Implementation Method 2
a second expansion device arranged at the suction-injection pipe
Implementation Method 3
a refrigeration cycle including a compressor, a first heat exchanger, a first expansion device, and second heat exchangers that are connected by pipes
Data Source
AI summary
An air-conditioning apparatus includes a suction-injection pipe that introduces a refrigerant in a liquid or two-phase state into a suction side of a compressor, an expansion device that is arranged at the suction-injection pipe, and a controller that regulates the suction-injection flow rate of a refrigerant introduced into the suction side of the compressor through the suction-injection pipe by controlling the opening degree of the expansion device.