Humidity-Based Compressor Control for Air Conditioner Defrosting
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Solution Overview
Problem
Conventional air conditioners perform defrosting operations uniformly regardless of outdoor humidity, leading to suboptimal defrosting and heating efficiency due to the lack of consideration for humidity conditions, resulting in increased defrosting frequency and duration which negatively impacts heating performance.
Innovation Solution
An air conditioner system that includes an outdoor unit with a compressor, outdoor temperature and humidity sensors, and a control part that adjusts the compressor's operation frequency based on dew-point temperature and evaporation pressure to prevent frosting, using reference pressures and humidity mapping to optimize defrosting and heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defrosting operation is performed uniformly according to predetermined time interval, then defrosting is performed regularly, but heating performance deteriorates due to increased defrosting frequency and duration
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-time interval defrosting to dynamic defrosting control based on real-time outdoor humidity detection. The control part adjusts defrosting timing and duration according to detected humidity levels, making the defrosting operation adaptive rather than static. This resolves the contradiction by enabling defrosting to occur only when necessary (high humidity conditions), thereby maintaining heating performance while ensuring effective defrosting when needed.
Solution Approach 2:
The patent changes the control parameter from time-based to humidity-based. By using outdoor humidity as the triggering parameter for defrosting operations, the system optimizes the balance between defrosting effectiveness and heating performance. The control part monitors humidity levels and initiates defrosting only when humidity exceeds threshold values, preventing unnecessary defrosting operations that would degrade heating performance.
2Power
If evaporator surface temperature is lowered to absorb heat from outdoor air, then heating operation is effective, but frosting occurs when temperature drops to freezing point
Solution Approach 1:
The patent implements feedback control by continuously monitoring outdoor humidity levels and using this information to predict and prevent frosting. The control part receives humidity data from the outdoor humidity detector and adjusts compressor operation accordingly. When humidity is high, the system preemptively adjusts operating parameters to prevent the evaporator surface temperature from dropping to freezing point, thus avoiding frost formation while maintaining heating capability.
Solution Approach 2:
The patent applies preliminary action by taking preventive measures before frosting occurs. Based on detected high outdoor humidity conditions, the control part adjusts compressor operation and refrigerant flow in advance to prevent the evaporator surface temperature from reaching the freezing point. This proactive approach prevents frost formation while maintaining effective heat absorption from outdoor air.
3Power
If compressor operation frequency is increased to improve heating output, then heating performance is enhanced, but evaporation pressure decreases causing increased frosting risk
Solution Approach 1:
The patent uses feedback control by monitoring evaporation pressure and outdoor humidity levels to dynamically adjust compressor operation frequency. The control part receives feedback from both the pressure detector (monitoring evaporation pressure) and outdoor humidity detector, and adjusts compressor speed accordingly. This dual-feedback mechanism allows the system to maintain optimal heating output while preventing evaporation pressure from dropping to levels that would cause frosting.
Solution Approach 2:
The patent changes the control approach from fixed compressor speed to variable speed control based on multiple parameters including outdoor humidity and evaporation pressure. The control part adjusts compressor operation frequency dynamically, increasing it when heating output is needed and outdoor humidity is low, and reducing it when high outdoor humidity creates frosting risk. This multi-parameter control resolves the contradiction between heating output and frosting prevention.
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 system effectively minimizes defrosting operations and enhances heating performance by dynamically adjusting compressor frequency according to outdoor humidity and pressure conditions, thereby improving efficiency and reducing frost formation on the evaporator.
Implementation Method 1
an outdoor temperature sensor installed on the outdoor unit to sense outdoor temperature
Implementation Method 2
an outdoor humidity recognition part installed on the outdoor unit to recognize information about outdoor humidity
Implementation Method 3
a low pressure sensor that senses an evaporation pressure of the evaporator
Implementation Method 4
an outdoor heat exchanger installed in an outdoor unit functions as a condenser, and an indoor heat exchanger installed in an indoor unit functions as an evaporator
Implementation Method 5
an indoor heat exchanger installed in an indoor unit functions as an evaporator
Implementation Method 6
a compressor, a condenser, an expansion device, and an evaporator, and performs a refrigerating cycle for compressing, condensing, expanding, and evaporating refrigerant
Implementation Method 7
a compressor, a condenser, an expansion device, and an evaporator, and performs a refrigerating cycle for compressing, condensing, expanding, and evaporating refrigerant
Implementation Method 8
a compressor, a condenser, an expansion device, and an evaporator, and performs a refrigerating cycle for compressing, condensing, expanding, and evaporating refrigerant
Implementation Method 9
When the surface temperature of the evaporator decreases to be equal to or lower than the freezing point, the condensate water is frozen to frost the outer surface of the evaporator
Data Source
AI summary
A method of controlling an air conditioner, including inputting, by an operation command input part, an operation command for the air conditioner through which a refrigerating cycle circulates; sensing, by an outside temperature sensor, an outside temperature; sensing, by an outside humidity recognition part, an outside humidity; sensing, by a low pressure sensor, a low pressure of the refrigerating cycle; recognizing, by a controller, information about the outside temperature, the outside humidity, and the low pressure; entering, by the controller, a changing mode in which a first target high pressure of the refrigerating cycle is changed when the low pressure is less than a first reference low pressure; and changing, by the controller, an operation frequency of a compressor of the air conditioner in response to a range of the low pressure when the changing mode is performed.