Refrigerator Bypass Flow Sensor for Frost-Based Defrost Timing
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Solution Overview
Problem
Existing refrigerator systems face inefficiencies in determining the optimal time for defrosting due to reliance on cumulative compressor operation time and external temperature, without considering the actual frost generation amount, leading to either inadequate defrosting or unnecessary power consumption.
Innovation Solution
A refrigerator design incorporating a bypass passage with a sensor that detects changes in air flow rate to determine the frost generation amount, using a heat-generating element and temperature-sensing element to accurately determine when defrosting is required, while minimizing passage length and preventing frost formation around the sensor.
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 defrosting timing accuracy deteriorates
Solution Approach 1:
The patent replaces the mechanical/time-based defrosting control method with a flow rate sensing system. Instead of using cumulative compressor operation time and external temperature (mechanical/clock-based measurement), the system uses a flow sensor to detect air flow rate changes through the evaporator, substituting mechanical timing with physical parameter measurement for more accurate defrosting determination
Solution Approach 2:
The patent implements feedback control by continuously monitoring the air flow rate through the evaporator and adjusting defrosting timing based on real-time conditions. The flow sensor provides continuous feedback on frost accumulation effects, allowing the system to adapt defrosting cycles to actual operating conditions rather than following a predetermined time schedule
2Ease of operation
If defrosting is performed based on fixed time cycle, then the control is simple, but power consumption increases due to unnecessary defrosting
Solution Approach 1:
The patent transitions from a static, fixed-time defrosting cycle to a dynamic control system that continuously monitors air flow rate and adjusts defrosting timing based on actual frost accumulation. The system adapts to varying operating conditions, user patterns, and environmental factors, performing defrosting only when flow rate changes indicate actual frost buildup rather than following a rigid time schedule
3Measurement precision
If sensor is placed directly in heat exchange space, then the sensing is direct, but frost generation around sensor increases
Solution Approach 1:
The patent introduces a bypass passage as an intermediary channel that allows air to flow between the heat exchange space and the sensor location without requiring the sensor to be directly exposed to the coldest conditions. This intermediary pathway enables indirect sensing of flow rate changes while protecting the sensor from direct frost formation, maintaining measurement accuracy without exposing the sensor to harmful freezing conditions
4Measurement precision
If bypass passage length is increased, then the sensing coverage is improved, but the response time deteriorates
Solution Approach 1:
The patent implements a bypass passage with optimized, limited length that provides sufficient sensing capability without excessive coverage. Rather than creating a long, extensive sensing pathway, the system uses a compact bypass passage that captures the essential flow rate changes needed to detect frost accumulation, achieving adequate sensing coverage with minimal response time delay
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 timing of defrosting operations based on actual frost accumulation, improving cooling performance and reducing power consumption by ensuring defrosting only when necessary.
Implementation Method 1
the sensor has an output value which varies according to a flow rate of air flowing through the bypass passage
Implementation Method 2
a heat-generating element and temperature-sensing element to accurately determine when defrosting is required
Implementation Method 3
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 4
If the air heat-exchanged with the evaporator is contained in moisture, 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
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AI summary
A refrigerator of the present invention comprises: an inner case forming a storage compartment; a cold air duct guiding the flow of air within the storage compartment and forming a heat exchange space with the inner case; an evaporator disposed in the heat exchange space between the inner case and the cold air duct; a bypass flow channel disposed in the cold air duct so as to allow the flow of air to bypass the evaporator; a sensor disposed in the bypass flow channel and comprising a sensor housing, a sensor PCB received in the sensor housing, a heating element installed on the sensor PCB so as to generate heat when an electric current is applied thereto, a temperature element for sensing the temperature of the heating element, and a molding material with which the sensor housing is filled; a defrosting means for removing frost formed on the surface of the evaporator; and a control unit for controlling the defrosting means on the basis of the value output from the sensor.