Switching Valve Pressure Balancing for Quiet Air Conditioner Mode Changes
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Solution Overview
Problem
Conventional air conditioners face challenges in minimizing noise generated when switching between cooling and heating modes due to the pressure difference across the switching valve, which is difficult to manage effectively with existing methods.
Innovation Solution
The air conditioner actively controls evaporating and condensing pressures in response to cooling or heating loads by adjusting the opening degrees of low-pressure valves and using electronic expansion valves to set target pressures for each indoor heat exchanger, allowing for precise control of the switching valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the outdoor fan is operated for a certain period of time to lower condensing pressure, then noise generated by pressure difference is reduced, but the evaporating pressure remains intact making it difficult to effectively reduce the pressure difference
Solution Approach 1:
The controller performs preliminary actions by operating the outdoor fan and adjusting the electronic expansion valve before switching the four-way valve, thereby proactively reducing the pressure difference between high-pressure and low-pressure sides to minimize switching noise
Solution Approach 2:
The system changes operational parameters by adjusting the electronic expansion valve opening degree and outdoor fan speed to dynamically control condensing pressure and evaporating pressure, enabling effective reduction of pressure difference across the switching valve
2Object-affected harmful factors
If active control of evaporating and condensing pressures is implemented, then noise during mode switching is minimized and thermo-off frequency is reduced, but system complexity increases
Solution Approach 1:
The electronic expansion valve and outdoor fan serve multiple functions: they control refrigerant flow and heat exchange during normal operation, and additionally control evaporating and condensing pressures during mode switching preparation, reducing the need for separate dedicated components
Solution Approach 2:
The controller continuously monitors system parameters and adjusts the electronic expansion valve and outdoor fan operation based on feedback, enabling precise pressure control during mode switching while maintaining system stability
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 approach reduces noise during mode switching and minimizes the frequency of indoor heat exchanger thermo-off, ensuring efficient operation and reduced noise levels by optimizing pressure settings based on load conditions.
Implementation Method 1
adjusting the opening degrees of low-pressure valves and using electronic expansion valves to set target pressures
Implementation Method 2
indoor heat exchangers; an outdoor heat exchanger
Implementation Method 3
a compressor
Implementation Method 4
a switching valve which selectively guides a refrigerant discharged from the compressor to the outdoor heat exchanger or the indoor heat exchangers
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
An air conditioner includes a controller; a compressor; an outdoor heat exchanger; indoor heat exchangers; a switching valve which selectively guides a refrigerant discharged from the compressor to the outdoor heat exchanger or the indoor heat exchangers; high-pressure pipes which connect the switching valve and the indoor heat exchangers, the high-pressure pipes in which high-pressure valves are installed; low-pressure pipes which connect an inlet of the compressor and the high-pressure pipes, the low-pressure pipes in which low-pressure valves are installed; indoor pipes which are opposite to the high-pressure pipes with respect to the indoor heat exchangers and connected to the indoor heat exchangers, the indoor pipes in which indoor expansion valves are installed; and a liquid pipe which connects the outdoor heat exchanger and the indoor pipes, the liquid pipe in which an outdoor expansion valve is installed.