Refrigerator Air Flow Sensor Control for Accurate Defrost Timing
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Solution Overview
Problem
Existing refrigerator systems face inefficiencies in determining the optimal time for defrosting operations due to reliance on cumulative compressor operation time and external temperature, without considering the amount of frost on the evaporator, leading to inaccurate defrosting cycles and increased power consumption.
Innovation Solution
A control method that detects residual frost on the evaporator using temperature differences between detection temperatures when the heat generating element is turned on and off, adjusting the defrosting cycle based on these measurements to accurately determine the need for defrosting and account for residual frost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If defrosting cycle is determined using cumulative compressor operation time and external temperature, then the control method is simple, but the accuracy of determining defrost time point deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring air flow rate through the evaporator and using this information to dynamically adjust defrosting cycle timing. The control device receives feedback signals from the air flow rate sensor and modifies defrosting operations based on actual frost accumulation conditions, creating a closed-loop control system that improves accuracy while maintaining operational simplicity.
Solution Approach 2:
The patent replaces traditional mechanical/time-based defrosting control with an air flow rate-based sensing system. Instead of relying solely on cumulative operation time counters and external temperature sensors, the system substitutes a more sophisticated air flow rate measurement mechanism that directly indicates frost accumulation levels, enabling more precise defrost timing determination.
2Device complexity
If defrosting is performed based on cumulative operation time and external temperature only, then the control system is simple, but power consumption increases due to unnecessary defrosting
Solution Approach 1:
The control system uses real-time air flow rate feedback to determine when defrosting is actually needed, rather than following a fixed time-based schedule. This feedback mechanism allows the system to avoid unnecessary defrosting operations when frost accumulation is minimal, thereby reducing power consumption while maintaining system simplicity.
Solution Approach 2:
The patent changes the control parameter from fixed time-based scheduling to dynamic air flow rate monitoring. By measuring air flow rate variations that indicate frost accumulation, the system adapts defrosting timing to actual conditions, reducing energy waste from premature or unnecessary defrosting operations while keeping the control system relatively simple.
3Device complexity
If air flow rate is not monitored, then the sensor system is simple, but the ability to detect frost accumulation deteriorates
Solution Approach 1:
The patent introduces an air flow rate sensor to replace or supplement traditional frost detection methods. The sensor system measures air flow characteristics that change with frost accumulation on the evaporator, providing a direct and accurate indication of frost levels without requiring complex imaging or multiple sensors, thus maintaining relative simplicity while improving detection precision.
Solution Approach 2:
The air flow rate acts as an intermediary parameter that indirectly indicates frost accumulation on the evaporator. Instead of directly measuring frost thickness or mass, the system monitors the air flow rate through the evaporator, which changes predictably as frost builds up, providing an accurate yet simple detection mechanism.
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 allows for precise determination of defrosting times, reducing energy consumption and improving cooling performance by ensuring accurate detection of frost levels and adjusting defrosting operations accordingly.
Implementation Method 1
a sensor having an output value that varies depending on the flow rate of air... detection temperatures of the heat generating element
Implementation Method 2
Air in the storage space is cooled while flowing to a space, in which the evaporator is disposed, so as to be heat-exchanged with the evaporator
Implementation Method 3
when the air is heat-exchanged with the evaporator, the moisture is frozen on a surface of the evaporator to generate frost on the surface of the evaporator
Data Source
AI summary
A method for controlling a refrigerator according to the present invention comprises the steps of: operating, for a set duration, a heating element of a sensor which responds to changes in air flow; sensing the temperature of the heating element in on or off state; and sensing the blockage of an air channel in the heat-exchange space on the basis of the difference in value of the temperature between a first sensed temperature (Ht1), which is the lowest value, and a second sensed temperature (Ht2), which is the highest value, from among the sensed temperatures of the heating element.