Defrost Timing Control in Air Conditioners Using Stable-State Detection
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Solution Overview
Problem
Air conditioners face challenges in accurately determining the entry time for defrosting operations during heating cycles, leading to inefficient heat exchange, reduced performance, and potential over- or under-defrosting due to uncertainties in frost formation and temperature changes.
Innovation Solution
An air conditioner control method that detects stable state conditions after defrosting, stores values, and uses these to determine the next defrosting entry time based on parameters like outdoor heat exchanger temperature, compressor operation, and fan rotation, ensuring accurate timing and minimizing unnecessary defrosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the air conditioner uses temperature change of the outdoor heat exchanger to determine entry time of the defrosting operation, then the defrosting operation can be triggered, but the entry time may not be accurately determined when outdoor temperature is low causing frequent or excessive defrosting
Solution Approach 1:
The patent segments the single temperature-based determination method into multiple independent determination methods: evaporation pressure difference method, outdoor heat exchanger temperature method, and operation time method. Each method operates independently to determine defrosting entry time, allowing the system to select the most reliable method based on current conditions, thereby improving both measurement precision and reliability.
Solution Approach 2:
The patent creates a universal defrosting determination system that can function through multiple pathways. The control unit is designed to accept and process multiple types of input signals (pressure differences, temperature changes, operation time) and can determine defrosting entry time through any of the three methods, making the system adaptable and reliable across various operating conditions.
2Reliability
If the air conditioner performs defrosting operation frequently to ensure thorough defrosting, then heating efficiency is maintained, but unnecessary defrosting operations increase power consumption and reduce user comfort
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors evaporation pressure, outdoor heat exchanger temperature, and operation time. Based on this feedback, the control unit determines the optimal defrosting entry time and adjusts the defrosting duration, ensuring thorough defrosting only when necessary and avoiding unnecessary power consumption.
Solution Approach 2:
The patent changes the determination parameters from a single temperature threshold to multiple dynamic parameters including evaporation pressure difference, outdoor heat exchanger temperature, and cumulative operation time. This allows the system to adaptively determine defrosting needs based on actual operating conditions, preventing both under-defrosting and unnecessary defrosting.
3Measurement precision
If the air conditioner uses multiple determination methods for defrosting entry time, then the accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent merges the three determination methods (evaporation pressure difference, outdoor heat exchanger temperature, and operation time) into a single integrated control unit. The control unit processes all three parameters simultaneously and determines defrosting entry time based on the combined information, improving accuracy while avoiding the need for separate complex control systems for each method.
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 improves the accuracy of defrosting timing, enhances heating performance, reduces noise, and minimizes power consumption by preventing unnecessary defrosting operations, thereby maintaining user comfort and efficiency.
Implementation Method 1
an outdoor heat exchanger of an outdoor unit absorbs heat as the result of evaporation
Implementation Method 2
the refrigerant in the outdoor heat exchanger is condensed with the result that the refrigerant radiates heat, which defrosts the outdoor heat exchanger
Data Source
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.