Frozen Confectionery Freezer Airflow for Temperature Uniformity
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Solution Overview
Problem
Conventional freezers for frozen confectionary products suffer from large temperature gradients due to heat ingress through the upper surface, leading to inefficient refrigeration and increased energy consumption when air circulation is used to mitigate these gradients.
Innovation Solution
Implementing a gentle air circulation system that moves colder air from the lower region to the upper region within the freezer, reducing temperature gradients without disturbing the air near the surface, thereby reducing the refrigeration load and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If turbulent air circulation is used to eliminate temperature gradients, then temperature homogeneity is improved, but energy consumption increases
Solution Approach 1:
The patent applies partial action by using a low-speed fan to generate only gentle air movement rather than strong turbulent flow. This partial circulation is sufficient to reduce temperature gradients to an acceptable level while avoiding the excessive energy consumption associated with high-speed air circulation. The fan runs at reduced speed to create just enough air movement to prevent large temperature differences without causing the harmful effects of turbulent flow.
Solution Approach 2:
The patent changes the operational parameter of air circulation from high-speed turbulent flow to low-speed gentle movement. By adjusting the fan speed parameter to a lower value, the system achieves temperature homogenization through laminar or transitional flow rather than turbulence, significantly reducing the energy required for air circulation while maintaining temperature uniformity within acceptable limits.
2Temperature
If air circulation means are operated to reduce temperature gradient, then temperature distribution is improved, but refrigeration load increases due to increased heat transport through surface
Solution Approach 1:
The patent uses partial air circulation at low speed to achieve sufficient temperature distribution improvement without creating excessive surface air movement. This gentle circulation is just enough to reduce temperature gradients internally while minimizing the disruption of the boundary layer at the freezer surface, thereby avoiding increased heat ingress and the associated increase in refrigeration load.
Solution Approach 2:
The patent applies preliminary action by establishing gentle air circulation before significant temperature gradients can develop and before excessive heat buildup occurs. The low-speed fan continuously maintains a mild air movement that prevents large temperature differences from forming in the first place, reducing the overall thermal load on the refrigeration system compared to allowing gradients to develop and then correcting them.
3Reliability
If refrigeration temperature is set much lower than product temperature, then product quality is maintained, but energy consumption increases
Solution Approach 1:
The patent changes the temperature parameter distribution within the freezer chamber by implementing gentle air circulation. This circulation reduces the temperature gradient between different zones, allowing the refrigeration system to operate at a higher average temperature while still maintaining products within their quality tolerance range. The mild air movement ensures uniform temperature distribution, enabling less aggressive refrigeration settings that consume less energy.
Solution Approach 2:
The patent implements a feedback mechanism where temperature sensors monitor the temperature distribution within the freezer chamber and adjust the fan speed accordingly. When temperature gradients become too large, the fan speed increases slightly to enhance circulation and redistribute heat. When temperature uniformity is achieved, the fan speed reduces, minimizing energy consumption. This feedback control allows the system to maintain product quality while optimizing energy usage by adjusting air circulation based on actual temperature conditions.
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 the freezer to operate at a higher base temperature, reducing energy consumption while maintaining product quality, with the energy savings exceeding the costs of operating the fan, resulting in lower overall energy use compared to both stagnant and turbulent air flow configurations.
Implementation Method 1
warm air is less dense than cold air... large temperature gradients are established due to fact that warm air is less dense than cold air
Implementation Method 2
heat ingress occurs through the upper surface of the chamber, as the walls and base are typically thermally insulated
Implementation Method 3
heat ingress occurs through the upper surface of the chamber
Implementation Method 4
the walls and base are typically thermally insulated
Data Source
Figure 1
Figure 2
AI summary
A freezer for storing frozen confectionery products, the freezer comprising a substantially sealed openable chamber for storing the frozen confectionery products and having a lower region and an upper region, the lower region comprising air circulation means for directing air from the lower region to the upper region and refrigeration means for chilling the chamber.