Air-conditioning apparatus
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Solution Overview
Problem
Existing air-conditioning apparatuses face challenges in defrosting outdoor heat exchangers during heating operations, leading to prolonged defrosting times and increased unit size due to the mixing of low-temperature and high-temperature refrigerants, and the need for multiple solenoid valves which increase installation space.
Innovation Solution
An air-conditioning apparatus with a switching valve system that allows high-temperature refrigerant from the compressor to be sequentially supplied to parallel flow passages of the outdoor heat exchanger, preventing refrigerant temperature mixing and eliminating the need for multiple solenoid valves by using a single switching valve to switch connection destinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple solenoid valves are used to switch connection destinations of flow passages, then defrosting efficiency is improved, but device complexity and installation space increase
Solution Approach 1:
The patent combines the functions of multiple solenoid valves into a single four-way switching valve. This switching valve integrates the connection switching functionality that would otherwise require multiple separate solenoid valves, thereby reducing device complexity and installation space while maintaining the ability to efficiently switch refrigerant flow to different flow passages for defrosting operations
Solution Approach 2:
The four-way switching valve performs multiple functions: it switches connection destinations of flow passages, controls refrigerant flow direction, and enables both heating and defrosting operations. This multi-functional design eliminates the need for multiple specialized solenoid valves, reducing system complexity while preserving defrosting efficiency
2Device complexity
If low-temperature refrigerant flows into all flow passages during heating operation, then refrigerant distribution is simplified, but defrosting time period is prolonged due to temperature mixing
Solution Approach 1:
The patent segments the flow passages into groups that can be independently controlled. During heating operation, the switching valve can direct low-temperature refrigerant to specific flow passages while directing high-temperature refrigerant to other passages for defrosting. This segmentation allows simultaneous heating and defrosting without refrigerant temperature mixing, reducing defrosting time while maintaining simplified flow control
Solution Approach 2:
The switching valve dynamically changes refrigerant flow distribution based on operational mode. During heating, it configures flow paths to optimize heat exchange; during defrosting, it redirects high-temperature refrigerant to frozen passages while preventing low-temperature refrigerant from mixing. This dynamic control enables efficient transition between modes without prolonged defrosting
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 efficient defrosting of the outdoor heat exchanger while maintaining heating operations, reducing defrosting time and preventing unit size and installation space increases, by ensuring the high-temperature refrigerant is effectively directed to specific passages without mixing with low-temperature refrigerant.
Implementation Method 1
high-temperature gas refrigerant discharged from the compressor is caused to flow through a part of the flow passages, and the flow passage through which the high-temperature gas refrigerant discharged from the compressor is caused to flow is sequentially switched
Implementation Method 2
an amount of heat received by the outdoor heat exchanger from the outside air is reduced
Data Source
AI summary
Provided is an air-conditioning apparatus including a switching valve and a bypass circuit. The switching valve is provided between an expansion valve and an outdoor heat exchanger. The bypass circuit has a first end connected to a refrigerant pipe connecting a compressor and an indoor heat exchanger to each other, and a second end connected to the switching valve. During a heating operation, the air-conditioning apparatus causes a rotating member of the switching valve to rotate to sequentially connect, to the bypass circuit, flow passages of the outdoor heat exchanger connected in parallel, to thereby defrost the outdoor heat exchanger while performing the heating operation.