Freezer Compressor Control for Low-Oscillation Food Preservation
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Solution Overview
Problem
Freezer burn, characterized by browning patches on food due to moisture loss, is a visible deterioration that existing methods fail to prevent effectively, leading to food wastage despite correct wrapping.
Innovation Solution
A method for controlling a refrigerating unit by adjusting the freezer temperature to a range of 2° C. to 10° C. lower than standard and limiting temperature oscillations to 1° C. to 0.1° C., combined with precise compressor control and sub-cooling before defrosting, to reduce moisture loss and freezer burn formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the freezer temperature is set to standard values with conventional on/off control, then energy consumption is moderate, but temperature oscillations cause moisture loss and freezer burn on food
Solution Approach 1:
The patent applies dynamics by transitioning from conventional on/off compressor control to inverter control that continuously adjusts compressor speed. This dynamic control allows the system to maintain stable freezer temperature (reducing oscillations to ±0.5°C or less) while adapting energy consumption to actual cooling needs, thereby preventing freezer burn without excessive energy use.
Solution Approach 2:
The patent implements parameter changes by modifying the temperature setpoint dynamically. During door opening events, the system temporarily lowers the temperature setpoint (e.g., from -18°C to -20°C or lower) to compensate for warm air infiltration and rapid temperature rise, then returns to normal operation. This parameter adjustment prevents temperature oscillations that cause moisture loss and freezer burn.
2Stability of the object's composition
If the compressor runs continuously at high capacity to maintain low temperature, then temperature stability improves, but energy consumption increases significantly
Solution Approach 1:
The inverter-controlled compressor operates dynamically, adjusting its speed continuously rather than running at full capacity or cycling on/off. The control system modulates compressor speed to match the actual cooling load, maintaining temperature stability (±0.5°C or less) while consuming only the necessary energy, avoiding both over-compression and excessive energy use.
Solution Approach 2:
The system employs feedback control where the temperature sensor continuously monitors freezer temperature and feeds this information back to the inverter controller. The controller adjusts compressor speed in real-time based on temperature deviations, ensuring stable temperature maintenance while optimizing energy consumption by running the compressor at the minimum necessary capacity.
3Productivity
If the defrosting cycle operates at high temperature to remove frost quickly, then defrosting efficiency improves, but temperature oscillations increase causing moisture loss
Solution Approach 1:
The defrosting system uses dynamic control with multiple temperature levels rather than a single high-temperature cycle. The inverter controller adjusts compressor and heater operation to create a multi-stage defrosting process that removes frost effectively while minimizing temperature oscillations in the food storage area, preventing moisture loss during defrosting.
Solution Approach 2:
The system implements periodic defrosting cycles with controlled duration and intensity. Rather than continuous high-temperature defrosting, the system applies periodic heating and compressor operation in a controlled sequence, removing frost gradually while maintaining relatively stable temperatures in the food compartment, thus preventing excessive moisture loss.
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 reduces freezer burn occurrence by 35% on average, with significant benefits for red meat, minimizing discoloration and frost formation, and maintaining food quality by stabilizing temperature fluctuations.
Implementation Method 1
a refrigeration circuit with a compressor... setting the set temperature of the freezing compartment to a value from 2° C. to 10° C. lower than the previously set value
Implementation Method 2
changing the on/off control or the cooling capacity of the compressor so that temperature oscillations in the freezing compartment are limited to a range from 1° C. to 0.1° C.
Data Source
AI summary
A method for controlling a refrigerating unit that includes the steps of providing a freezing compartment, a user interface and a refrigeration circuit with a compressor; and setting a controlling routine through the user interface for avoiding freezer burns on food products to be stored in the freezing compartment, upon the setting changing the set temperature of the freezing compartment to a value from 2° C. to 10° C. lower than the previously set value, and changing the on/off control or the cooling capacity of the compressor so that temperature oscillations in the freezing compartment are limited to a range from 1° C. to 0.1° C.