Air Conditioner Defrosting Control Using Stable State Detection
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Solution Overview
Problem
Air conditioners face reduced heat exchange performance and compressor reliability during heating operations due to frost on outdoor heat exchangers, leading to inaccurate defrosting operation timing and inefficiencies, as the distinction between frost-induced pressure drops and actual defrosting needs is unclear.
Innovation Solution
An air conditioner control method that determines a stable state by monitoring compressor operation rate, outdoor fan rotations, and heat exchanger temperatures, storing these values to accurately calculate the entry time for defrosting operations, ensuring proper timing and minimizing unnecessary or incomplete defrosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defrosting operation is performed frequently to ensure outdoor heat exchanger is defrosted, then reliability of compressor is improved, but heating efficiency is reduced and energy consumption increases
Solution Approach 1:
The system stores stable state values detected after defrosting operations and uses this feedback to intelligently determine when the next defrosting operation should occur. The controller compares current sensor readings with stored stable state values to calculate difference values, enabling accurate determination of defrosting entry timing without excessive or insufficient defrosting operations.
Solution Approach 2:
The system performs preliminary detection and storage of stable state values after defrosting operations complete. By storing these baseline values in advance, the system can accurately determine when frost has actually formed on the heat exchanger, preventing both premature and delayed defrosting operations.
2Productivity
If defrosting operation is delayed to maintain heating efficiency, then energy consumption is reduced, but heat exchange performance deteriorates due to frost accumulation
Solution Approach 1:
The system replaces traditional mechanical temperature-based defrosting triggers with an intelligent detection system that uses sensor data and stored stable state values to determine defrosting timing. By calculating difference values between current readings and stored baselines, the system accurately identifies when frost formation actually occurs, optimizing the balance between maintaining heat exchange performance and energy efficiency.
3Device complexity
If temperature of outdoor heat exchanger is used to determine defrosting entry time, then detection simplicity is improved, but measurement precision deteriorates due to inability to distinguish frost-induced pressure drops from low outdoor temperature effects
Solution Approach 1:
The system introduces stable state values as an intermediary reference point. By storing baseline values detected after defrosting operations and comparing current sensor readings against these intermediaries, the system can accurately distinguish between temperature changes caused by frost formation versus those caused by ambient conditions, significantly improving measurement precision.
Solution Approach 2:
Instead of relying on a single temperature threshold, the system performs multiple detection cycles and stores multiple stable state values. By calculating difference values from these stored values, the system uses a more comprehensive approach that partially compensates for the limitations of simple temperature-based detection, improving accuracy without significantly increasing system complexity.
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 method improves the accuracy of defrosting operation timing, enhances heating performance, reduces noise and power consumption, and maintains user comfort by minimizing unnecessary defrosting interruptions and ensuring efficient heat exchange.
Implementation Method 1
an outdoor heat exchanger of an outdoor unit absorbs heat as the result of evaporation
Implementation Method 2
the surface temperature of the outdoor heat exchanger is greatly reduced with the result that condensed water is formed on the surface
Implementation Method 3
the refrigerant in the outdoor heat exchanger is condensed with the result that the refrigerant radiates heat, which defrosts the outdoor heat exchanger
Implementation Method 4
the refrigerant radiates heat
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An air conditioner, having an outdoor unit and an indoor unit, to perform a heating operation and a defrosting operation, the air conditioner including a detection unit to detect a state of at least one selected between the outdoor unit and the indoor unit and to output the detected value, a controller to determine whether the air conditioner is in a stable state when the defrosting operation is completed and, upon determining that the air conditioner is in the stable state, to control the detected value output from the detection unit to determine entry time of the next defrosting operation, and a storage unit to store a value detected in the stable state. The entry time of the defrosting operation is accurately determined, thereby minimizing the number of times of the defrosting operation during the heating operation.