Patent Application
20190328155
The present invention relates to a freezer cabinet and method for adapting a freezer cabinet for containing frozen confectionery products.
Retail outlets for frozen confectionery typically store the frozen confectionery in a freezer cabinet. Such freezers are essentially the same as domestic freezer appliances, having a chamber in which the frozen confectionery is stored, in which the temperature is maintained by refrigeration apparatus.
Most frozen confectionery products are to be stored within narrow temperature ranges, in order to maintain product quality. However, one drawback of such freezer cabinets is that they tend to suffer from large temperature gradients. Such temperature gradients are established due to the fact that warm air is less dense than cold air and also because the majority of the heat ingress occurs through the upper surface of the chamber, as the walls and base are typically thermally insulated.
Often this temperature gradient is merely tolerated and large temperature differences can exist between the average product temperature and the refrigerant to compensate for heat entering the cabinet through the upper surface. Further, in order to ensure that the maximum allowable product temperature is not breached, the refrigeration temperature needs to be set much lower than the temperature of the products, especially those products in the upper regions of the freezer chamber.
Japanese laid open utility model publication 57-116,164 U relates to showcases equipped with a sliding door.
Japanese laid open utility model publication 47-018,856 U relates to refrigerating showcases.
Japanese laid open utility model publication 57-090,675 U relates to showcases equipped with a sliding door.
Japanese patent application publication JP 11-264652 A relates to a low-temperature showcase using a see-through door.
U.S. Pat. No. 2,619,804 relates to refrigerators and is particularly concerned with maintaining a storage space of a refrigerator at a low temperature.
The present inventors have found that providing a freezer cabinet having a specific configuration of panels can provide certain advantages.
In a first aspect the invention relates to a freezer cabinet for storing frozen confectionery products, the freezer cabinet comprising:
The presence of the further panel serves to provide a layer of quiescent air between the upper surface panel and further panel, although the air between the two panels is in gaseous communication with the remainder of the air in the storage chamber.
Thus the further panel has the effect of the quiescent region mixing much less with the cold air below this quiescent region. 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.
The reduced heat transfer rate means that the thermal load on the freezer is reduced. This means that the freezer can operate at a lower power requirement for a given maximum product temperature and also can provide a reduced thermal gradient as less heat is flowing into the chamber.
Without wishing to be bound by theory, the improved thermal properties from the presence of the further panel are believed to arise from the quiescent air region between the two panels rather than the thermal insulating properties of the further panel.
Furthermore, the present inventors have found that by limiting the amount of surface area of the opening covered by the further panel, the formation of condensation on the further panel can be reduced or even eliminated, thus allowing excellent visibility of the products in the chamber. In the present invention it should be understood that that the amount of the surface area of the opening covered by the further panel refers to the surface area of the opening in a horizontal plane at a height of the lowest part of the further panel.
Preferably the further panel covers less than 92% of the surface area of the opening, more preferably less than 90%, more preferably still less than 89% and most preferably less than 88%.
To avoid the air in the quiescent region mixing too much with the air in the chamber, it is preferred that the further panel covers at least 50% of the surface area of the opening, more preferably at least 60%, more preferably still at least 70% and most preferably at least 80%.
The space in the opening that is not covered by the further panel is conveniently formed by at least one gap between at least one edge of the further panel and at least one inner surface of a sidewall delimiting the chamber wherein the inner surface faces the chamber. Preferably the cabinet comprises at least two such gaps with each gap being at opposite ends of the further panel. Most preferably there is a continuous gap surrounding the entire further panel.
Additionally or alternatively the space in the opening that is not covered by the further panel may be formed by one or more holes and/or recesses in the further panel.
As used herein, where two entities are specified to be “substantially parallel” in a given direction, this means that the entities extend in said direction within 20 degrees of parallel, more preferably within 10 degrees, more preferably still within 5 degrees and most preferably from 0 to 2 degrees of parallel.
The further panel is preferably substantially parallel to the upper surface panel in at least one horizontal direction. More preferably the direction is the direction in which the openable section in the further panel is slideable. Most preferably the further panel is substantially parallel to the upper surface panel in both horizontal directions.
The chamber is typically delimited by a base, at least one side wall and the upper surface panel. In a typical arrangement the chamber has a rectangular base but other configurations such as, for example, a circular base are possible.
It is also common for the chamber to comprise baskets, which contain the frozen confectionery products and prevent them contacting the cold walls of the chamber, more preferably the chamber comprises removable baskets.
Several types of refrigeration system may be used in the cabinet of the present invention.
Known systems include, for example, forced-air systems where air is forced over a cooling element in order to cool the air and then the cooled air is forcefully circulated around the chamber. The air is moved over the cooling element and/or around the chamber with the use of one or more fans. Another type of system is more passive and relies on a coolant evaporator mounted in and/or on the side wall of the chamber. Where the evaporator is mounted within the side walls it typically comprises tubes coiling around the side walls and is commonly referred to as a “skin evaporator” (such tubes may or may not be mounted on metal plates). Where the evaporator is mounted on the wall it typically comprises one or more metal plates which are shaped to contain channels for the coolant and is commonly referred to as a “roll-bond evaporator”. In the present invention the more preferred refrigeration system is of the skin-evaporator and/or roll-bond evaporator type, most preferably skin evaporator, as these systems do not disturb the quiescent layer. Additionally or alternatively it is preferred that the cabinet does not comprise a forced-air cooling system.
The present inventors have found that where a coolant evaporator is mounted in and/or on the side wall, the positioning of the further panel with respect to the evaporator can influence the effectiveness of the further panel in reducing the thermal load on the freezer. In particular if 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 increased then the effectiveness of the further panel is increased. Preferably the height distance (H) is at least 5 mm, more preferably at least 7 mm, more preferably still at least 8 mm and most preferably at least 10 mm. Preferably the further panel is not too high above the evaporator as this can reduce the size of the quiescent layer. Thus it is preferred that H is no more than 100 mm, more preferably no more than 80 mm, more preferably still no more than 70 mm, even more preferably no more than 60 mm and most preferably no more than 50 mm.
An additional or alternative way of ensuring that the quiescent layer does not become too small is to ensure that the sum of the thickness of the upper surface panel and the further panel is less than 90% of the height thickness of the upper surface panel, quiescent region and further panel. The thickness of the upper surface panel, and likewise for the further panel, is defined as the distance between the upper most surface facing away from the freezer chamber and lower most surface facing towards the freezer chamber of the panel. The height thickness is defined as the distance between the upper most surface facing away from the freezer chamber of upper surface panel and the lower most surface facing towards the freezer chamber of the further panel.
More preferably the sum of the thickness of the upper surface panel and the further panel is less than 80%, even more preferable less than 70%, still more preferably less than 60% and most preferably from 10 to 50% of the height thickness.
The upper surface panel and the further panel both comprise at least one slideably openable section to allow easier access to the frozen confectionery products in the freezer. Preferably the upper surface panel and the further panel both comprise two slideably openable sections. Typically each openable section will not take up the entirety of the panel, but for example half of the total surface of the upper surface panel and half of the total surface area of the further panel.
Preferably each of the slideably openable sections in the upper surface panel is aligned with the corresponding slideably openable section in the further panel such that when moved parallel to one another an opening in each panel is created of about the same surface area.
Preferably the slideably openable sections in the upper surface panel have about the same shape as the slideably openable sections in the further panel. The slideably openable sections in the further panel are typically of a different dimension to those of the upper surface panel, preferably the slideably openable sections in the further panel are smaller (i.e. cover a smaller surface area of the opening) than those of the upper surface panel.
Preferably the slideably openable sections make up the entirety of the upper surface panel and the further panel.
As discussed above, the gas in the quiescent region remains in gaseous communication with the air in the storage chamber. Thus the mere presence of the substantially parallel upper surface panel and further panel provides sufficient entrapment of the gas between them, without requiring entrapment of the gas at the edges of the panels. It has been found that the absence of a sealing frame all around the edges of the panels for the entrapment of gas (as for example present in a double glazed window) provides for less air turbulence, and therefore better energy performance, when the freezer cabinet is opened and also eliminates thermal conduction through the sealing frame.
However, it is preferable that each of the slideably openable sections in the upper surface panel is attached to the corresponding slideably openable section in the further panel such that the slideably openable section in the further panel remains unmoved relative to the slideably openable section in the upper surface panel when the latter is opened and closed. This can be achieved for example by struts, brackets or side panels connecting the corresponding slideably openable sections together and fixing the distance they are spaced apart from each other.
Preferably each of the slideably openable sections slides just under or above the remainder of the corresponding upper surface panel or further panel. It will be understood that if more than one slideably openable section is present in each of the upper surface panel and further panel the remaining portion of the panel is also preferably a slideably openable section.
At least part of the upper surface panel and further panel is transparent thereby serving as a viewing window, so that the consumer can view the frozen confectionery products before opening the slideably openable sections to remove the chosen product. Preferably the entire upper surface panel and further panel of the freezer are transparent to enable as many stored confectionery products to be viewable as possible without opening the openable sections. It will be understood that a frame, if present, to support the upper surface panel and/or further panel does not have to be transparent for the entire upper surface panel and further panel of the freezer to be transparent.
Preferably at least part of the upper surface panel is made from glass, plastic or a combination thereof. Glass is preferred as the upper surface panel is exposed to the outside and more vulnerable for wear and tear like e.g. scratching.
Preferably at least part of the further panel is made from glass, plastic or a combination thereof. Glass is preferred.
The upper surface panel and/or further panel can comprise a low emissivity coating to further enhance the thermal insulation provided by the panels. This is especially preferred when both panels are transparent. It is therefore preferred that the upper surface panel and further panel comprise a low emissivity coating.
For a typical ice-cream product freezer the maximum tolerable product temperature is −18° C. Thus the temperature at the upper end of the chamber is typically from −20 to −18° C. At the lower end of the chamber the temperature is typically from −26 to −24° C.
The temperature gradient in the freezer cabinet is preferably such that the difference in average product temperature between the upper end of the chamber and the lower end of the chamber is less than 6° C., more preferably less than 5° C., even more preferably less than 4° C., or even between 0 and 3° C.
Benefits of the invention in power consumption reduction and/or vertical temperature gradient reduction within the storage chamber and/or condensation reduction are also applicable in freezers where the set points are between −5° C. and −30° C., and even more preferably between −8° C. and −25° C. Such set points e.g. can be preferred for different types of food products.
It will be appreciated that the freezer cabinet of the invention is especially suitable for environmental conditions (i.e. external conditions) in which the freezer has to operate in temperatures of more than 30° C., i.e. higher than Climate Class 4.
The invention further provides for a method of providing a freezer cabinet according to the invention as described in any embodiment of the first aspect above, the method involving providing an existing freezer cabinet comprising the chamber having the opening substantially sealed by the upper surface panel; and installing the further panel inside the chamber in an arrangement substantially parallel to but spaced away from the upper surface panel. Adding the further panel creates 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.
The method of the present invention can be applied to existing freezer cabinets from which frozen confectionery products are commonly sold from retail outlets. Thus, substantial power consumption savings can be obtained without requiring wholesale replacement of existing freezers in use or increasing condensation that reduces visibility of products in such freezer cabinets.
The invention will now be illustrated by way of example and with reference to the following figures, in which:
The rectangular base (13) along with side walls (12, 14) and an upper surface (16) delimit the chamber in which frozen confections, such as ice cream, are stored and displayed. The upper surface (16) is split into two halves made up of a lower slideably openable section (18) which slides just under an upper section (20) of the upper surface. The upper section (20) also acts as a slideably openable section and can slide over the lower section (18). Both sections (18, 20) are each made of a single sheet of reinforced glass.
Unlike a typical cabinet, the cabinet in
As can be seen in
The further section (22) is fitted by attaching it by struts (26) to the lower openable section (18) of the upper surface (16). In this way further panel (22) can be slideably moved together with lower openable section (18). In a similar manner the other further panel (24) is attached to upper openable section (20) by struts (30). Therefore the sections are openable by sliding across without disturbing most of the air in quiescent region.
Additionally the spacing of the further panels (22, 24) from the upper surface (16) could be modified by modifying the height of the struts (26) and (30).
In
As can be seen in
As can also be seen in
As best seen in
Whereas the slideably openable sections (18, 20) of the rectangular cabinet shown in
The cabinet in
As can be seen in
The further section (122) is fitted by attaching it by struts (126) to the lower openable section (118) of the upper surface (116). In this way further panel (122) can be slideably moved together with lower openable section (118). In a similar manner the other further panel (124) is attached to upper openable section (120) by struts (130). Therefore the sections are openable by sliding around without disturbing most of the air in quiescent region.
Experiments were carried out on either an AHT VT300 freezer cabinet (Rio H 125G, 291 litres) modified as shown in
The experiments were performed in a controlled environmental chamber (Climate Class 4). Each cabinet was allowed to reach equilibrium state with the lid closed. Each of the openable sections was then opened and closed every 5 minutes for 2 hours to simulate use in a retail environment. During the tests the power consumption was monitored and/or observations were recorded of condensation on the further sections.
Tests 1 to 8
The effect of the amount of area covered by the further panel was investigated using the VT300 freezer modified with further panels of different size such that the gaps between the panels and the side walls (A and B as described above) were varied. The height (H) distance was kept constant at 10 mm in these experiments. The results are shown in Table 1.
The data in table 1 show that all of the tests using the lid modified with the further panel had much better energy efficiency than the unmodified cabinet. For test 2, where the further panel covered the entire opening, severe condensation formed on a large surface area of the further panel sections. This condensation was decreased in test 3 and progressively reduced as the amount of opening covered by the further panel was reduced. In tests 7 and 8, where less than 89% of the opening was covered, the condensation was eliminated without substantially affecting the energy efficiency gain afforded by the presence of the further panel.
Test 9
The effect of the positioning of the further panel relative to the evaporator was investigated using the VT300 freezer modified with further panels wherein the height (H) distance was varied. In these experiments there was no gap between the further panels and the sidewalls (i.e. both A and B were zero). The results are shown in Table 2.
The data in table 2 show that when the further panel is placed below the top of the evaporator, the energy benefits are reduced. This is believed to be because the air in the quiescent region is cooled too much. No condensation was observed in test 9 as the moisture in the quiescent region was able to migrate directly to the evaporator.
Tests 10 to 15
The effect of the positioning of the further panel relative to the evaporator was investigated using the freezer with the roll-bond evaporator and modified with further panels wherein the height (H) distance was varied. In these experiments the gaps with the sidewalls (A) and (B) were maintained at 50 mm and 15 mm respectively. The results are shown in Table 3.
The data in table 3 clearly show that increasing the height distance (H) improved the efficiency of the freezer, except that increasing the height above about 80 mm gave no further benefit and above 100 mm the benefit even appeared to decrease slightly.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16206826.6 | Dec 2016 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/081826 | 12/7/2017 | WO | 00 |
