Mode Switcher Pressure Equalization for Quieter Multi-Split AC
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Solution Overview
Problem
Existing heat recovery multi-split air conditioning systems experience significant noise during mode switching due to large differential pressures across solenoid valves, which is not effectively addressed by existing solutions.
Innovation Solution
Incorporating high-pressure and low-pressure electronic expansion valves in series within the mode switcher, gradually opening and closing them during mode switching to reduce differential pressure, combined with the use of mufflers on gas pipes to mitigate noise from liquid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a solenoid valve is used to switch liquid pipe and high/low pressure gas pipe in the mode switcher, then the mode switching function is achieved, but the noise during mode switching becomes very obvious due to large differential pressure
Solution Approach 1:
The patent introduces an intermediary device (electronic expansion valve or noise reduction valve) between the high-pressure and low-pressure sides to gradually equalize the pressure difference during mode switching. This intermediary component allows the pressure to transition smoothly rather than abruptly, thereby reducing the noise generated by rapid pressure equalization while maintaining the mode switching function.
Solution Approach 2:
The patent employs a dynamically controllable valve (electronic expansion valve) that can adjust its opening degree during mode switching. By dynamically controlling the valve opening, the system can manage the pressure differential progression, allowing the noise to be reduced by controlling the rate of pressure equalization rather than having it occur instantaneously.
2Adaptability or versatility
If a solenoid valve is used in the mode switcher, then the mode switching function is achieved, but the operation noise of the system becomes more obvious
Solution Approach 1:
The patent introduces an intermediary device (electronic expansion valve or noise reduction valve) between the high-pressure and low-pressure sides to gradually equalize the pressure difference during mode switching. This intermediary component allows the pressure to transition smoothly rather than abruptly, thereby reducing the noise generated by rapid pressure equalization while maintaining the mode switching function.
Solution Approach 2:
The patent replaces the traditional solenoid valve (electromechanical system) with an electronic expansion valve that offers more precise and gradual control capability. This substitution allows for smoother operation and reduced noise by enabling continuous adjustment of the valve opening rather than abrupt on/off switching.
3Object-generated harmful factors
If electronic expansion valves are gradually opened and closed during mode switching, then the differential pressure is reduced and switching noise is minimized, but the complexity of the mode switcher increases
Solution Approach 1:
The patent makes the existing electronic expansion valve in the refrigerant cycle serve dual functions: its primary function of regulating refrigerant flow and its secondary function of controlling pressure differential during mode switching. By making this existing component multi-functional, the system reduces switching noise without adding separate dedicated components, thereby minimizing the increase in system complexity.
Solution Approach 2:
The patent combines the mode switching function with the existing electronic expansion valve control system. By merging these functions and using the same control circuitry and valve mechanism for both refrigerant flow regulation and pressure differential management during mode transitions, the system achieves noise reduction while avoiding the need for completely separate control systems.
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
Effectively reduces the noise associated with mode switching in heat recovery multi-split air conditioning systems by minimizing differential pressure changes and suppressing sound from liquid flow, resulting in a quieter operation.
Implementation Method 1
the electronic expansion valves and the low-pressure electronic expansion valve are configured to be gradually opened and closed during air conditioning mode switching to reduce a differential pressure between before and after a mode conversion operation
Implementation Method 2
the liquid pipe section is further connected with a supercooling pipe in series, the heat recovery multi-split air conditioning system further includes a first bypass pipeline led from the main liquid pipe to the main low-pressure gas pipe, the first bypass pipeline is connected with the supercooling pipe and performs heat exchange
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A mode switcher includes at least one mode conversion branch (B1, B2, BN, B11, B1N, BN1, BNN). The mode conversion branch (B1, B2, BN, B11, B1N, BN1, BNN) includes: a liquid pipe section, a high-pressure gas pipe section and a low-pressure gas pipe section. Both ends of the liquid pipe section are respectively used for connecting a main liquid pipe (P1) and a branch liquid pipe (P4). One end of the high-pressure gas pipe section and one end of the low-pressure gas pipe section are respectively used for connecting a main high-pressure gas pipe (P3) and a main low-pressure gas pipe (P2), and another end of the high-pressure gas pipe section and another end of the low-pressure gas pipe section are both connected with a branch gas pipe (P5). The mode switcher further includes a high-pressure electronic expansion valve (3) and a low-pressure electronic expansion valve (2), the high-pressure electronic expansion valve (3) and the low-pressure electronic expansion valve (2) are respectively arranged in series in the high-pressure gas pipe section and the low-pressure gas pipe section, and are configured to gradually be opened and closed during air conditioning mode switching to reduce a differential pressure between before and after a mode conversion operation. A heat recovery multi-split air conditioning system and control method are further provided. The mode switcher can effectively reduce the noise when air conditioning mode is switched by the mode switcher.