Air conditioning device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air-conditioning apparatuses face challenges in stabilizing discharge temperature and degree of subcooling, particularly when switching between cooling and heating modes or with long extension pipes, leading to potential compressor damage and operational instability.
Innovation Solution
The air-conditioning apparatus incorporates a refrigerant circuit with a compressor, heat exchangers, expansion devices, and an accumulator, featuring bypass pipes and an auxiliary heat exchanger to control refrigerant flow rates and temperatures, ensuring stable operation and subcooling even with long extension pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an expansion device is attached to the subcooling heat exchanger to control refrigerant flow rate, then the discharge temperature can be controlled to a target value, but the degree of subcooling at the outlet of the condenser cannot be independently controlled, causing pressure loss in long extension pipes and two-phase state occurrence
Solution Approach 1:
The patent divides the refrigerant flow control into two independent paths: one path through the subcooling heat exchanger controlled by a first expansion device to maintain subcooling degree, and another path through a bypass pipe with a second expansion device to control discharge temperature. This segmentation allows independent control of both parameters without compromising refrigerant state stability.
Solution Approach 2:
The bypass pipe acts as an intermediary path that allows a portion of the refrigerant to bypass the subcooling heat exchanger. This intermediary path enables fine-tuning of the discharge temperature by mixing subcooled refrigerant with refrigerant from the bypass, while the main path through the subcooling heat exchanger maintains the required subcooling degree.
2Adaptability or versatility
If check valves are arranged in parallel to expansion devices to enable suction injection both in cooling and heating modes, then the air-conditioning apparatus can operate in both modes, but a special indoor unit is necessary, preventing use of normal indoor units
Solution Approach 1:
The patent designs the indoor unit with a universal configuration that can operate in both cooling and heating modes using the same expansion device and check valve arrangement. The outdoor unit incorporates the liquid injection capability through its expansion device and check valve, eliminating the need for special indoor units and allowing use of standard indoor units in both operation modes.
Solution Approach 2:
Instead of modifying the indoor unit to enable liquid injection (which would require special components), the patent inverts the approach by placing the liquid injection mechanism in the outdoor unit. This inversion allows the indoor unit to remain a standard, simple configuration while achieving the desired multi-mode operation capability.
3Temperature
If only injection to the portion between the high-pressure liquid pipe and the compressor is performed, then the discharge temperature can be lowered, but cases where the circulation path is inversed (switching between cooling and heating) cannot be coped with
Solution Approach 1:
The patent implements a dynamic system where the injection path and refrigerant flow direction can change based on operation mode. The check valve and bypass pipe configuration allow the system to automatically adapt: in cooling mode, liquid refrigerant is injected into the compressor suction side; in heating mode, the flow path reverses and injection occurs at the appropriate location in the reversed circulation path, maintaining discharge temperature control in both modes.
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 allows for stable control of compressor discharge temperature and refrigerant subcooling, preventing damage and maintaining a longer apparatus lifespan, regardless of operation mode or pipe length.
Implementation Method 1
a compressor (10) including a compression chamber and an injection port through which refrigerant is introduced into the compression chamber, the compressor being configured to compress refrigerant and discharge the compressed refrigerant
Implementation Method 2
a first heat exchanger that exchanges heat with the refrigerant, a subcooling heat exchanger that includes a first flow passage and a second flow passage and exchanges heat between a portion of the refrigerant flowing in the first flow passage and another portion of the refrigerant flowing in the second flow passage
Implementation Method 3
a first expansion device to decompress the refrigerant
Implementation Method 4
a refrigerant circuit formed by connecting, with pipes, a compressor including a compression chamber and an injection port through which refrigerant is introduced into the compression chamber, the compressor being configured to compress refrigerant and discharge the compressed refrigerant
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is an air-conditioning apparatus 100 including a refrigerant circuit formed by connecting, with pipes, a compressor 10 including a compression chamber and an injection port through which refrigerant is introduced into the compression chamber, the compressor 10 being configured to compress refrigerant and discharge the compressed refrigerant, a first heat exchanger 12 that exchanges heat with the refrigerant, a subcooling heat exchanger 13 that includes a first flow passage and a second flow passage and exchanges heat between a portion of the refrigerant flowing in the first flow passage and another portion of the refrigerant flowing in the second flow passage to subcool the portion of refrigerant flowing in the first flow passage, a first expansion device 16 to decompress the refrigerant, a second heat exchanger 17 that exchanges heat with the refrigerant, and an accumulator 15 connected to a suction side of the compressor 10 and configured to store excess refrigerant, so that the refrigerant is circulated through the refrigerant circuit, the air-conditioning apparatus 100 comprising: a first bypass pipe 4a that connects the second flow passage of the subcooling heat exchanger 13 with a segment of the pipes, the segment being positioned on a refrigerant inflow side of the accumulator 15; an expansion device 14a to adjust a flow rate of the refrigerant flowing in the first bypass pipe 4a; a second bypass pipe 4b that connects a segment of the pipes with the injection port, the segment being positioned between the first heat exchanger 12 and the second heat exchanger 17; and an expansion device 14b to adjust a flow rate of the refrigerant flowing in the second bypass pipe 4b.