Freezer cabinet and method for adapting a freezer cabinet
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Solution Overview
Problem
Freezer cabinets for frozen confectionery products face significant temperature gradients due to heat ingress through the upper surface, leading to increased thermal loads and power consumption, as well as condensation issues that affect product visibility.
Innovation Solution
A freezer cabinet design featuring a further panel inside the chamber, parallel to and spaced from the upper surface panel, creating a quiescent region that reduces heat transfer by minimizing air mixing with the cold air, thus allowing the freezer to operate at a lower power requirement and maintaining a reduced temperature gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional freezer cabinet design is used with an upper surface panel, then the chamber is sealed and products are protected, but large temperature gradients occur due to heat ingress through the upper surface
Solution Approach 1:
A further panel is introduced as an intermediary element between the upper surface panel and the products. This further panel creates a quiescent air region that acts as a thermal mediator, reducing direct heat transfer from the upper surface to the products while maintaining the sealed environment.
Solution Approach 2:
The solution adds a vertical dimension to the insulation strategy by introducing a further panel at a specific height above the evaporator. This creates a three-dimensional quiescent air region rather than relying solely on two-dimensional panel insulation, effectively adding spatial complexity to reduce heat ingress.
2Temperature
If the refrigeration temperature is set lower to compensate for heat ingress, then product temperature is maintained, but power consumption increases
Solution Approach 1:
The quiescent air region acts as a pre-established thermal buffer or cushion between the upper surface and the products. This beforehand cushioning effect reduces the thermal shock and heat ingress before it reaches the products, allowing for more efficient temperature control and reduced power consumption.
3Illumination intensity
If transparent panels are used for visibility, then products are visible through the upper surface panel, but condensation occurs affecting visibility
Solution Approach 1:
The further panel and the quiescent air region between the panels serve as an intermediary thermal barrier that prevents moisture condensation on the transparent panels. This intermediary layer maintains a temperature gradient that keeps the inner surface of the transparent panels above the dew point, eliminating condensation while preserving visibility.
4Temperature
If a forced-air cooling system is used, then cooling is effective, but the quiescent layer is disturbed reducing its insulating effect
Solution Approach 1:
The cooling system is designed with local quality differentiation: the evaporator provides localized cooling at the bottom of the chamber, while the upper region maintains a quiescent, undisturbed air layer. This local quality approach allows effective cooling where needed while preserving the insulating properties of the quiescent region above.
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 design reduces power consumption and minimizes temperature gradients within the storage chamber, while also reducing condensation and enhancing product visibility by maintaining a stable thermal barrier without increasing the thermal insulating properties of the panels.
Implementation Method 1
The presence of the further panel serves to provide a layer of quiescent air between the upper surface panel and further panel... The reduction in mixing means that the quiescent region becomes warmer than it would without the presence of the further panel. Thus the temperature difference between the upper quiescent region in contact with the upper surface panel of the freezer and the ambient temperature of the surroundings of the freezer is therefore reduced which results in a reduced heat transfer rate through the upper surface panel and therefore into the freezer chamber.
Implementation Method 2
the majority of the heat ingress occurs through the upper surface of the chamber... results in a reduced heat transfer rate through the upper surface panel and therefore into the freezer chamber
Implementation Method 3
at least part of the upper surface panel and further panel is transparent such that at least part of the inside of the chamber is visible through the upper surface panel and further panel
Data Source
AI summary
Disclosed is a freezer cabinet (10) for storing frozen confectionery products, the freezer cabinet comprising: a chamber having an opening substantially sealed by an upper surface panel (18, 20); and a further panel (22, 24) inside the chamber being spaced away from the upper surface panel and substantially parallel to the upper surface panel in at least one direction and creating a quiescent region between the upper surface panel and further panel wherein the quiescent region is in gaseous communication with the air in the chamber. At least part of the upper surface panel and further panel is transparent such that at least part of the inside of the chamber is visible through the upper surface panel and further panel; the upper surface panel comprises at least one slideably openable section (18, 20); the further panel comprises at least one slideably openable section (22, 24); and the chamber comprises a side wall (12, 14) and a coolant evaporator (40) mounted in and/or on the side wall. The height distance (H) between the further panel, measured from the lowest face of the further panel facing the chamber, and the highest part of the evaporator is at least 5 mm.