Compressor Heating Control for Refrigerant Stagnation Detection
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Solution Overview
Problem
Existing air-conditioning apparatuses wastefully consume power by heating the compressor when refrigerant does not stagnate, due to reliance on outdoor air temperature or refrigerant saturation temperature for heating control, leading to unnecessary energy usage.
Innovation Solution
Implement a control system that determines the refrigerant stagnation state by comparing the compressor temperature change rate with the refrigerant temperature change rate, ending heating when the compressor temperature change rate exceeds the refrigerant temperature change rate, indicating complete gasification of refrigerant in the lubricant oil, and using this method to prevent unnecessary heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is heated based on outdoor air temperature or refrigerant saturation temperature, then refrigerant stagnation is prevented, but unnecessary power consumption occurs when refrigerant does not stagnate
Solution Approach 1:
The system continuously monitors compressor temperature and refrigerant temperature in real-time, using this feedback to dynamically adjust heating control. When compressor temperature exceeds refrigerant temperature, heating is automatically stopped, preventing wasteful energy consumption while ensuring refrigerant stagnation prevention when needed.
Solution Approach 2:
The invention changes the control parameter from fixed thresholds (outdoor air temperature or saturation temperature) to dynamic temperature differential monitoring. By comparing actual compressor and refrigerant temperatures, the system adapts heating control to real-time conditions, eliminating unnecessary heating when refrigerant has already gasified.
2Reliability
If heating is continued after refrigerant gasification, then lubrication protection is maintained, but energy waste increases
Solution Approach 1:
The system uses real-time temperature feedback from both compressor and refrigerant to determine when heating should be terminated. When compressor temperature rises above refrigerant temperature, indicating complete gasification, the feedback mechanism stops heating, maintaining lubrication protection only when necessary and eliminating energy waste afterward.
Solution Approach 2:
Instead of applying excessive heating continuously, the system applies heating partially and only when the temperature differential indicates refrigerant stagnation risk. This partial action approach provides sufficient protection against lubrication failure while avoiding the excessive energy consumption of continuous heating.
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 effectively prevents heating after the refrigerant has fully gasified, reducing standby power consumption and ensuring efficient energy use by accurately determining refrigerant stagnation states.
Implementation Method 1
a method of applying low voltage high frequency current to a coil of a motor installed in the compressor to heat the compressor by Joule heat generated in the coil without rotation of the motor
Implementation Method 2
when the compressor temperature change rate is higher than the refrigerant temperature change rate, it is identified that the entire liquid refrigerant in the lubricant oil in the compressor has been gasified
Data Source
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AI summary
To obtain an air-conditioning apparatus that appropriately determines the state of stagnating refrigerant in a compressor, and suppresses power consumption while the air-conditioning apparatus is not in operation. When a compressor temperature change rate Rc1 is determined to be higher than a refrigerant temperature change rate Rr1, a controller 31 identifies that liquid refrigerant in a lubricant oil 100 in a compressor 1 has been totally gasified, stops energizing a motor unit 62, and ends a heating operation of the compressor 1.