Air-conditioning apparatus
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Solution Overview
Problem
Existing air-conditioning apparatus methods for preventing refrigerant stagnation in compressors often result in unnecessary preheating and increased energy consumption, as they fail to accurately determine the refrigerant stagnation level and lubricant oil concentration, leading to inefficient power usage.
Innovation Solution
An air-conditioning apparatus equipped with a liquid-level and concentration detection sensor that simultaneously measures the liquid surface level and lubricant oil concentration in the compressor, allowing for precise determination of when preheating is necessary, thereby reducing unneeded preheating and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is preheated based on outdoor air temperature and outer wall temperature, then refrigerant stagnation can be prevented, but unnecessary preheating occurs and energy consumption increases
Solution Approach 1:
The patent replaces temperature-based detection (mechanical/thermal sensing) with electrical impedance detection to determine refrigerant stagnation. The microcontroller measures the impedance of the motor coil, which changes based on refrigerant presence, enabling more accurate determination of when preheating is actually needed and reducing unnecessary energy consumption.
Solution Approach 2:
The patent changes the detection parameter from temperature (outdoor air temperature and outer wall temperature) to electrical impedance of the motor coil. This parameter change enables more precise detection of refrigerant stagnation conditions, allowing the system to preheat only when necessary, thus resolving the contradiction between reliability and energy consumption.
2Reliability
If the compressor is preheated based on liquid surface level detection, then refrigerant stagnation can be detected, but lubricant oil concentration is not determined leading to unnecessary preheating
Solution Approach 1:
The patent replaces mechanical level detection with electrical impedance measurement of the motor coil. The impedance changes in response to both liquid refrigerant level and lubricant oil concentration, providing a more comprehensive and precise measurement that accounts for the actual lubrication conditions in the compressor.
Solution Approach 2:
The impedance detection method serves multiple functions simultaneously: it detects both the liquid refrigerant level and the lubricant oil concentration in the compressor. This multi-functionality eliminates the need for separate sensors and provides more accurate determination of when preheating is actually required, addressing the measurement precision limitation.
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
The solution ensures preheating only occurs when the refrigerant level is high and the lubricant oil concentration is below the minimum required, minimizing power consumption by eliminating unnecessary heating and ensuring sufficient lubrication in the compressor.
Implementation Method 1
a motor of the compressor is energized in an open phase state (applying alternating current with a missing phase to the motor so that the motor does not rotate, thus making a coil generate heat)
Implementation Method 2
A liquid-level and concentration detection sensor that simultaneously measures the liquid surface level and lubricant oil concentration in the compressor
Data Source
Figure 1~2
Figure 3
AI summary
[Problem] To provide an air-conditioning apparatus that is capable of reducing power consumption by eliminating unneeded preheating by determining whether preheating is needed or not taking into account, as well as, concentration of a lubricant oil in a compressor. [Solution] The air-conditioning apparatus includes an outdoor air temperature sensor 10 detecting an outdoor temperature; a compressor temperature sensor 11 detecting a temperature of an outer wall of a compressor; a liquid-level and concentration detection sensor 8 detecting a liquid surface level in the compressor and a concentration of a lubricant oil in a liquid in the compressor; an electric heater 3a heating the compressor; and a controller 100 that carries out preheating to the compressor by driving the electric heater 3a when a detection value of the outdoor air temperature sensor 10 is higher than or equal to a detection value of the compressor temperature sensor 11 and, further, when the liquid surface level detected by the liquid-level and concentration detection sensor 8 is higher than or equal to a predetermined level and the concentration of the lubricant oil in the liquid is lower than a preset minimum required concentration.