Freezer Temperature Control to Prevent Food Freezer Burn
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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 adequately prevent, leading to food wastage despite correct wrapping.
Innovation Solution
A method for controlling a refrigeration 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 prevent freezer burn.
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
Solution Approach 1:
The patent applies dynamics by transitioning from conventional on/off compressor control to inverter control, enabling continuous adjustment of compressor speed. This dynamic control maintains temperature within a narrow range (±0.5°C) by adjusting compressor output to match actual cooling demand, preventing temperature oscillations that cause freezer burn while optimizing energy consumption.
Solution Approach 2:
The patent changes the temperature setpoint parameter from standard freezer temperatures (-18°C) to lower temperatures (-20°C to -25°C). This parameter change reduces the temperature differential during cooling cycles, minimizing temperature oscillations and moisture loss from food, thereby preventing freezer burn while the inverter control ensures energy efficiency.
2Stability of the object's composition
If the compressor runs continuously at high capacity, then temperature stability is improved, but energy waste increases
Solution Approach 1:
The inverter-controlled compressor provides continuous speed adjustment rather than fixed high-capacity operation. The compressor speed dynamically responds to temperature feedback, maintaining stability only when necessary and reducing speed when temperature is within the acceptable range, thereby eliminating energy waste from continuous high-capacity operation.
Solution Approach 2:
The system implements feedback control by continuously monitoring freezer temperature and adjusting compressor speed accordingly. When temperature approaches the lower limit of the set range, compressor speed is reduced; when temperature approaches the upper limit, speed increases. This closed-loop feedback ensures temperature stability while optimizing energy consumption.
3Reliability
If defrosting is performed frequently, then ice buildup is prevented, but temperature fluctuations increase causing freezer burn
Solution Approach 1:
The system performs preliminary sub-cooling of the freezer to temperatures below the normal setpoint before initiating defrosting. This preliminary action creates a temperature buffer that compensates for the heat input during defrosting, ensuring that the freezer temperature remains stable throughout the defrosting process and preventing temperature oscillations that would cause freezer burn.
Solution Approach 2:
The inverter compressor continues operating at adjusted speeds during defrosting rather than shutting off completely. This continuous operation maintains cooling capacity to counterbalance the heat introduced during defrosting, ensuring uninterrupted temperature control and preventing the temperature instability that leads to freezer burn.
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 method effectively reduces freezer burn by up to 35% by maintaining a stable temperature and minimizing temperature fluctuations, preserving food quality and reducing discoloration, especially in red meat.
Implementation Method 1
a refrigeration circuit with a compressor
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.