Compressor Discharge Hole Positioning to Suppress Refrigerant Counter-Flow
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Solution Overview
Problem
Conventional air conditioning machines experience refrigerant counter-flow through the discharge hole of the compressor towards the indoor heat exchanger after a pump down operation, leading to inefficiencies and potential leaks.
Innovation Solution
The air conditioning machine incorporates a compressor with a compression member that stops overlapping the discharge hole at the end of the pump down operation, combined with a refrigerant leakage sensing unit and a pump down operation control unit to accumulate refrigerant in the outdoor heat exchanger, reducing counter-flow by resisting refrigerant flow through the discharge hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump down operation is carried out to accumulate refrigerant in the outdoor heat exchanger, then the refrigerant leakage can be detected and contained, but the refrigerant counter-flows through the discharge hole toward the indoor heat exchanger after the operation ends
Solution Approach 1:
The compression member is positioned in advance to overlap the discharge hole before the pump down operation ends. This preliminary positioning prevents refrigerant counter-flow from occurring in the first place, rather than attempting to stop it after the problem arises. The control unit adjusts the compression member's position during the pump down operation to ensure it blocks the discharge hole path.
Solution Approach 2:
The compression member acts as an intermediary element between the outdoor heat exchanger and the discharge hole. By positioning the compression member to overlap the discharge hole, it creates a physical barrier that mediates and blocks the refrigerant flow path, preventing direct counter-flow from the outdoor heat exchanger toward the indoor heat exchanger.
2Reliability
If the compression member stops at a position overlapping the discharge hole, then refrigerant counter-flow is suppressed, but the compressor structure and control complexity increase
Solution Approach 1:
The compression member's position is made dynamic rather than fixed. The control unit adjusts the compression member's position based on the operational phase - during pump down operation, it positions the compression member to overlap the discharge hole, and at other times, it returns to normal operating positions. This dynamic adjustment allows the system to achieve refrigerant flow control only when needed, minimizing overall complexity.
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 effectively suppresses refrigerant counter-flow from the outdoor to the indoor heat exchanger, enhancing operational efficiency and leak prevention by ensuring the refrigerant remains in the outdoor heat exchanger post-pump down.
Implementation Method 1
a compression member that is placed in the cylinder chamber and that compresses the flammable refrigerant
Implementation Method 2
the compression member stops at a position where the compression member overlaps at least a portion of the discharge hole... the compression member resists flow of the flammable refrigerant
Data Source
AI summary
An air conditioning machine is provided by which refrigerant collected into an outdoor heat exchanger is suppressed from counter-flowing through a discharge hole of a compressor toward a side of an indoor heat exchanger after the end of a pump down operation. The air conditioning machine includes a refrigerant circuit, a refrigerant leakage sensor that senses leakage of the flammable refrigerant from the refrigerant circuit, and a control unit that carries out a pump down operation for accumulating the flammable refrigerant in the outdoor heat exchanger when the leakage of the flammable refrigerant is sensed. At the end of the pump down operation, the pump down operation control unit controls the compressor so that the compression member stops at a position where the compression member overlaps at least a portion of the discharge hole when viewed in an axial direction of the cylinder chamber.