The invention relates to open display refrigerators, and to cooling units (refrigerators or freezers) which have doors comprising transparent windows. The invention also relates to methods of modifying such open display refrigerators and cooling units.

Open display refrigerators are commonly used in retail environments, such as supermarkets, to store and display products, such as meat and dairy products, which must be kept at lower than ambient temperatures. The open front of such a refrigerator makes it easy for customers to view the products being displayed and to retrieve products they wish to purchase from the refrigerator.

This type of refrigerator has an air curtain, which is established by blowing cold air across the front of the refrigerator. The air curtain issues from an air outlet at the top of the refrigerator towards an air inlet at the bottom of the refrigerator. The air inlet recovers air from the air curtain and recirculates it to the air outlet via a cooling heat exchanger and fan.

Generally, it is intended that the air curtain follows a broadly linear path from the air outlet to the air inlet thereby preventing cold air in the refrigerator from mixing with warm air exterior to the refrigerator. However, some configurations include a sizeable void between the uppermost shelf and the air outlet into which air from the air curtain tends to rush. This causes the air curtain to deviate from the intended generally linear path and move towards the interior of the refrigerator. Where the air curtain is drawn towards the interior of the refrigerator, the air flow of the air curtain is broken up and becomes more turbulent when compared to an air curtain that follows a generally linear path. The breaking up of the air curtain and the turbulence causes the air curtain to be less efficient at preventing cold air in the refrigerator from mixing with warm air exterior to the refrigerator and hence causes the interior of the refrigerator to be warmer than a refrigerator with a generally linear air curtain.

A further inefficiency arises where warm air (i.e. air that is warmer than the refrigerated interior) proximate the top exterior surface of the refrigerator is drawn around the front uppermost edge of the refrigerator by the flowing air of the air curtain and impinges on the air curtain as the air curtain leaves the air outlet. This causes warm air to become entrained in the air curtain and also breaks the smooth flow of the air curtain. Again, this causes the interior of the refrigerator to be warmer than a refrigerator with a generally linear air curtain. For refrigerators with an uppermost shelf that is installed at an angle to the normal, where an edge of the shelf distal to the rear of the refrigerator is lower than an edge of the shelf proximate the rear of the refrigerator, the void between the angled uppermost shelf and the air outlet is larger than with a refrigerator comprising a flat uppermost shelf that is not installed at an angle. Hence the issue of the air curtain deviating from a generally linear path when an angled shelf is used is even more pronounced. Generally these angled shelves do not have any additional air guides or aerofoils for guiding the air curtain, because they can be cumbersome to fit to angled shelves and generally retailers are unwilling to fit them to angled shelves. As such, it is important that the air curtain follows a generally linear path because the path of the air curtain is not purposefully altered or maintained between the point at which the air curtain is established and the point at which the air curtain enters the air inlet.

In accordance with a first aspect of the invention, there is provided an open display refrigerator comprising: a refrigerated storage space, air in the refrigerated storage space being separated from air exterior to the open display refrigerator by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet, and an air guide coupled to the air outlet or air duct and extending from the air outlet such that it bypasses a portion of a void between the uppermost shelf and the air outlet, whereby the air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet.

In this aspect, by "interface between the air curtain and the air exterior to the refrigerator" it is meant that the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the refrigerator, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthest from a rear interior wall of the refrigerator, meets the air exterior to the open display refrigerator.

In accordance with a second aspect of the invention, there is provided a cooling unit comprising an interior space and a door; wherein the door comprises a transparent window and separates the interior space from air external to the cooling unit; and wherein the interior space comprises (i) a refrigerated storage space and (ii) an access space; wherein air in the refrigerated storage space is separated from air in the access space by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet, and an air guide coupled to the air outlet or air duct and extending from the air outlet such that it bypasses a portion of a void between the uppermost shelf and the air outlet, whereby the air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet.

In this aspect, by "interface between the air curtain and the access space" it is meant the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the cooling unit, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is further from a rear interior wall of the cooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features described in the following paragraphs may relate to open display refrigerators or cooling units according to any of the first or second aspects of the invention.

As the air guide bypasses a portion of the void between the uppermost shelf and the air outlet, the effect of the void on the path of the air curtain is reduced and hence the air curtain follows a more linear path. Further, as the air guide extends from the air outlet, the air guide helps prevent warm air proximate the top exterior surface of the refrigerator from being drawn around the front uppermost edge of the refrigerator and impinging on the air curtain as the air curtain leaves the air outlet, because the air guide forms a barrier that extends from the air outlet.

An advantage of using the air guide is that any honeycomb structure that is present in the air outlet may be removed. This reduces the resistance to the air flowing through the air outlet and enhances the performance of the air curtain, as the velocity of the air curtain is increased. An increase in velocity makes the air curtain more resistant to being drawn into the void between the uppermost shelf and the air outlet as well as being more resistant to breaking up when warm air impinges on the air curtain.

In some embodiments, an uppermost shelf is at an angle to the horizontal, such that an edge of the shelf that is proximate a rear wall of the refrigerated storage space is higher than an edge of the shelf that is distal to the rear wall of the refrigerated storage space.

In some embodiments, the air guide comprises an air guide inlet through which the air enters and an air guide outlet at which the air curtain is established, and wherein the air guide outlet is offset relative to the air guide inlet. The air guide outlet may be offset away from, or be offset distal to, the rear wall of the refrigerated storage space, with respect to the air guide inlet. The body of the air guide may have a chicane shape or an "S" shape. The chicane shape or the "S" shape may be made up of a curve in a first direction and a curve in a second direction.

Alternatively, the body of the air guide may comprise a single curve. In some embodiments a part of the air guide may extend into the duct. In particular, an outermost side or a distal side (with respect to the refrigerated interior) of the air guide may extend into the duct. A technical advantage of all of these configurations is that the air guide can be better customised to work with the air flow characteristics of different fridges.

In some embodiments, the air guide comprises an air guide inlet through which the air enters and an air guide outlet at which the air curtain is established, and wherein the air guide outlet is aligned with the air guide inlet.

In some embodiments, a cross sectional area of the air guide inlet is larger than a cross sectional area of an air guide outlet, thereby causing the velocity of the air to increase as it passes through the air guide. An advantage of this arrangement is that the increase in air speed makes the air curtain more resistant to being drawn into the void and also helps to prevent the warm air drawn from the volume proximate the top exterior surface of the refrigerator from disrupting the path of the air curtain and being entrained into the air curtain.

In some embodiments, a cross sectional area of the air guide inlet is smaller than a cross sectional area of an air guide outlet. A technical advantage of such an air guide is that computer modelling shows that this improves the air flow of the air curtain in some types of refrigerator.

In some embodiments, a cross sectional area of the air guide inlet is the same, or is substantially the same, as a cross sectional area of an air guide outlet.

In some embodiments, there is at least one additional air outlet in a rear interior wall of the refrigerator or cooling unit.

In some embodiments, the refrigerator or cooling unit includes a honeycomb structure positioned in the air outlet, the honeycomb structure being a cellular matrix of channels which extend in a longitudinal direction parallel to the air flow.

In some embodiments, the refrigerator or cooling unit include a honeycomb structure positioned in the air guide outlet, the honeycomb structure being a cellular matrix of channels which extend in a longitudinal direction parallel to the air flow of the air curtain.

In some embodiments, the cooling unit is a refrigerator. In some embodiments, the cooling unit is a freezer.

In accordance with a third aspect of the invention, there is provided a method of selecting an air guide from a plurality of air guides for use with an open display refrigerator, wherein the open display refrigerator comprises a refrigerated storage space, air in the refrigerated storage space being separated from air exterior to the open display refrigerator by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet and wherein the method comprises: a) providing an array of temperature sensors within an interior of the open display refrigerator; b) measuring an initial temperature difference between the warmest temperature recorded by the array of temperature sensors and the coldest temperature recorded by the array of temperature sensors; c) coupling one or more air guides to the air outlet or air duct such that the or each air guide extends from the air outlet and bypasses a portion of a void between the uppermost shelf and the air outlet, whereby the air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet; d) measuring a respective final temperature difference associated with the or each air guide, the or each final temperature difference being the temperature difference between the warmest temperature recorded by the array of temperature sensors and the coldest temperature recorded by the array of temperature sensors after the associated air guide has been coupled to the air outlet or air duct; e) selecting an air guide from the one or more air guides, whereby the difference between the initial temperature difference and the final temperature difference associated with the selected air guide is at least a threshold

temperature difference, or selecting the air guide from the one or more air guides for which the difference between the initial temperature difference and the associated final temperature difference is greatest.

In this aspect, by "interface between the air curtain and the air exterior to the refrigerator" it is meant that the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the refrigerator, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthest from a rear interior wall of the refrigerator, meets the air exterior to the open display refrigerator.

In accordance with a fourth aspect of the invention, there is provided a method of selecting an air guide from a plurality of air guides for use with a cooling unit, wherein the cooling unit comprises an interior space and a door; wherein the door comprises a transparent window and separates the interior space from air external to the cooling unit; wherein the interior space comprises (i) a refrigerated storage space and (ii) an access space; wherein air in the refrigerated storage space is separated from air in the access space by an air curtain established by a fan which blows air towards an air outlet for recovery by a corresponding air inlet which recirculates air from the air curtain into an air duct coupled to the air outlet and wherein the method comprises: a) providing an array of temperature sensors within an interior of the cooling unit; b) measuring an initial temperature difference between the warmest temperature recorded by the array of temperature sensors and the coldest temperature recorded by the array of temperature sensors; c) coupling one or more air guides to the air outlet or air duct such that the or each air guide extends from the air outlet and bypasses a portion of a void between the uppermost shelf and the air outlet, whereby the air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet; d) measuring a respective final temperature difference associated with the or each air guide, the or each final temperature difference being the temperature difference between the warmest temperature recorded by the array of temperature sensors and the coldest temperature recorded by the array of temperature sensors after the associated air guide has been coupled to the air outlet or air duct; e) selecting an air guide from the one or more air guides, whereby the difference between the initial temperature difference and the final temperature difference associated with the selected air guide is at least a threshold temperature difference, or selecting the air guide from the one or more air guides for which the difference between the initial temperature difference and the associated final temperature difference is greatest.

In this aspect, by "interface between the air curtain and the access space" it is meant the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the cooling unit, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthers from a rear interior wall of the cooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features described in the following paragraphs may relate to open display refrigerators or cooling units according to any of the third or fourth aspects of the invention.

The temperature may be measured by placing numerous jelly-bricks (examples of jelly-bricks known in the art are Tylose packs or M-Packs) on the shelves of the refrigerator. Each jelly-brick has its own temperature probe, each of which makes up the array of temperature probes, so that the temperature at different points in the fridge can be tracked. As the location of the warmest jelly-brick and the location of the coolest jelly-brick may change with the addition of the air guide and/or adjustments made to the air guide, the difference between the warmest jelly-brick and the coolest jelly brick is measured.

The pre-determined threshold may be any meaningful temperature difference and will depend on the size and the geometry of the refrigerator. Meaningful temperature differences may be any number, at increments of 0.1°C, in the range of 0.1°C-10°C. In practice, it is likely that values that are multiples of 0.5°C and 1°C would be chosen. The temperature difference may be optimised by selecting an air guide with dimensions (including length, diameter, change in cross- section, amount of offset) that gives the biggest reduction in temperature difference.

In some embodiments, the array of temperature sensors are provided within the refrigerated storage space.

In some embodiments, a temperature sensor of the array of temperature sensors is provided proximate the air inlet.

In some embodiments, the air guide, and hence the path of the air curtain, is adjusted such that the temperature difference is further reduced. Examples of adjusting the air guide include positioning where the air guide is coupled to the air outlet or duct, adjusting an adjustable part joint on the air guide, such that the air guide inlet remains static and the air guide outlet is moveable or adjusting a plastic part of the air guide, such that a cross-section of the air guide is reduced or increased.

In accordance with a fifth aspect of the invention, there is provided a kit for retrofitting an air guide to an open display refrigerator, wherein the open display refrigerator comprises a refrigerated storage space, air in the refrigerated storage space being separated from air exterior to the open display refrigerator by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet and wherein the kit comprises: an air guide for coupling to the air outlet or air duct; and an attachment for fastening the air guide to the air outlet or air duct.

In this aspect, by "interface between the air curtain and the air exterior to the refrigerator" it is meant that the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the refrigerator, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthest from a rear interior wall of the refrigerator, meets the air exterior to the open display refrigerator.

In accordance with a sixth aspect of the invention, there is provided a kit for retrofitting an air guide to a cooling unit, wherein the cooling unit comprises an interior space and a door;

wherein the door comprises a transparent window and separates the interior space from air external to the cooling unit; and wherein the interior space comprises (i) a refrigerated storage space and (ii) an access space; wherein air in the refrigerated storage space is separated from air in the access space by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet, and wherein the kit comprises: an air guide for coupling to the air outlet or air duct; and an attachment for fastening the air guide to the air outlet or air duct.

In this aspect, by "interface between the air curtain and the access space" it is meant the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the cooling unit, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthers from a rear interior wall of the cooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features described in the following paragraphs may relate to open display refrigerators or cooling units according to any of the fifth or sixth aspects of the invention.

In some embodiments, the attachment comprises clips integral to the air guide, which are received in the open air refrigerator or the cooling unit proximate the air outlet or the air duct.

In some embodiments, the attachment comprises screws or rivets.

In some embodiments, the attachment comprises mastic or adhesive.

In accordance with a seventh aspect of the invention, there is provided a method of modifying an open display refrigerator, wherein the open display refrigerator comprises a refrigerated storage space, air in the refrigerated storage space being separated from air exterior to the open display refrigerator by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet, the method comprising: coupling an air guide to the air outlet or air duct, wherein the air guide has an air guiding surface which causes the air to bypass a portion of a void between the uppermost shelf and the air outlet or air duct prior to it leaving an air guide outlet, such that an air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet.

In this aspect, by "interface between the air curtain and the air exterior to the refrigerator" it is meant that the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the refrigerator, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthest from a rear interior wall of the refrigerator, meets the air exterior to the open display refrigerator.

In accordance with an eighth aspect of the invention, there is provided a method of modifying a cooling unit, wherein the cooling unit comprises an interior space and a door; wherein the door comprises a transparent window and separates the interior space from air external to the cooling unit; wherein the interior space comprises (i) a refrigerated storage space and (ii) an access space; wherein air in the refrigerated storage space is separated from air in the access space by an air curtain established by a fan which blows air towards an air outlet for recovery by a corresponding air inlet which recirculates air from the air curtain into an air duct coupled to the air outlet and wherein the method comprises: coupling an air guide to the air outlet or air duct, wherein the air guide has an air guiding surface which causes the air to bypass a portion of a void between the uppermost shelf and the air outlet or air duct prior to it leaving an air guide outlet, such that an air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet.

In this aspect, by "interface between the air curtain and the access space" it is meant the boundary where the air at a distal edge of the air curtain (which may be cooled by a heat exchanger of the cooling unit, and is blown through the air outlet by the fan), i.e. the edge of the air curtain which is furthers from a rear interior wall of the cooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features described in the following paragraphs may relate to open display refrigerators or cooling units according to any of the seventh or eighth aspects of the invention.

In some embodiments, the air guide is coupled to the air outlet or air duct by clips integral to the air guide, which are received in the open air refrigerator or the cooling unit proximate the air outlet or the air duct. In some embodiments, the air guide is coupled to the air outlet or air duct with screws or rivets.

In some embodiments, the air guide is coupled to the air outlet or air duct with mastic or adhesive.

In some embodiments, the air guide comprises an air guide inlet through which the air enters and an air guide outlet at which the air curtain is established, and wherein the air guide outlet is offset relative to the air guide inlet. The air guide outlet may be offset away from, or be offset distal to, the rear wall of the refrigerated storage space, with respect to the air guide inlet. The body of the air guide may have a chicane shape or an "S" shape. The chicane shape or the "S" shape may be made up of a curve in a first direction and a curve in a second direction.

Alternatively, the body of the air guide may comprise a single curve. In some embodiments a part of the air guide may extend into the duct. In particular, an outermost side or a distal side (with respect to the refrigerated interior) of the air guide may extend into the duct. A technical advantage of all of these configurations is that the air guide can be better customised to work with the air flow characteristics of different fridges.

In some embodiments, the air guide comprises an air guide inlet through which the air enters and an air guide outlet at which the air curtain is established, and wherein the air guide outlet is aligned with the air guide inlet.

In some embodiments, a cross sectional area of the air guide inlet is larger than a cross sectional area of an air guide outlet, thereby causing the velocity of the air to increase as it passes through the air guide.

In some embodiments, a cross sectional area of the air guide inlet is smaller than a cross sectional area of an air guide outlet.

In some embodiments, a cross sectional area of the air guide inlet is the same, or is substantially the same, as a cross sectional area of an air guide outlet.

In some embodiments, the method further comprises removing a honeycomb structure from the air guide outlet or air duct, the honeycomb structure being a cellular matrix of channels which extend in a longitudinal direction parallel to the air flow of the air curtain.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows an open display refrigerator in which the shelves are angled and a void is formed between the uppermost shelf and the air outlet.

Figure 2 shows the difference between the intended line of the air curtain of the open display refrigerator of Figure 1 and the actual path of the air curtain due to the void between the uppermost shelf and the air outlet and the warm air which is drawn from the top of the refrigerator.

Figure 3 shows an open air refrigerator with an air guide coupled to the air outlet.

Figure 4 shows method steps for selecting an air guide from a plurality of air guides for use with a refrigerator.

Figure 1 shows a cross-section through an open display refrigerator 1. The refrigerator has a storage space 2 that is maintained at a lower than ambient temperature. Within the storage space 2, there are four angled storages shelves 3a-3d. Different embodiments may have one, two, three, five or any number of storage shelves which may be flat, may be at an angle or may be a mix of angled and flat shelves. A typical angle for the angled storage shelves is 20°, however shelves at other angles may be used, as long as the product being refrigerated does not slide off of the shelves. As can be seen, a void 6 is formed between the uppermost storage shelf 3a and the air outlet 4. The refrigerator 1 establishes an air curtain (not shown) by a fan (not shown) which blows cold air towards an air outlet 4, out of the air outlet 4 and towards an air inlet 5. Air inlet 5 recovers air from the air curtain and a fan (not shown) within the refrigerator 1 recirculates the air to the air outlet 4. A cooling unit or heat exchanger (not shown) within the refrigerator 1 maintains the recirculated air (and hence the air blown through the air outlet 4 to form the air curtain) at a desired temperature. The desired temperature is chosen to be lower than ambient and acts to prevent cold air in the storage space 2 from mixing with warm air exterior to the refrigerator.

In Figure 2, the impact of the void 6 and the impact of warm air being drawn around the top of the refrigerator on the intended path of the air curtain is shown. The path of the warm air is indicated by the curved arrow 7. The intended path of the air curtain is indicated by the dotted line 8 and the deflected path of the air curtain is indicated by the dashed line 9. As can be seen, the air curtain moves towards the interior of the refrigerator in an unintended manner, which leads to increased temperatures at the bottom of the refrigerated storage space 2, when compared to a refrigerator that has a generally linear air curtain. Figure 3 shows a solution as provided by the present invention to the problem associated with the void between the uppermost shelf and the air outlet and also the problem associated with warm air being drawn from the top of the refrigerator and impinging on the air curtain. A cross- section through the open display refrigerator 1 is shown. As in Figures 1 and 2, the refrigerator 1 comprises a refrigerated storage space 2. Air in the refrigerated storage space 2 is separated from air exterior to the open display refrigerator 1 by an air curtain, indicated by the dashed line 10, established by a fan (not shown) which blows air towards an air outlet 4 and through an air guide 12 coupled to the air outlet 4 towards a corresponding air inlet, which recovers air from the air curtain for recirculation through an air duct 11 to the air guide 12. The air guide extends from the air outlet 4 such that it bypasses a portion of the void 6 formed between the uppermost shelf 3a and the air outlet 4. As shown, the air guide outlet may be offset away from, or be offset distal to, the rear wall of the refrigerated storage space with respect to the air guide inlet. This results in an air curtain that follows a more linear path, as the effect of the void on the air curtain is reduced. This is realised because the air guide bypasses a portion of the void between the uppermost shelf and the air outlet and prevents air from rushing into the void, hence the effect of the void on the path of the air curtain is reduced and the air curtain follows a more linear path. Further, as the air guide extends from the air outlet, the air guide helps prevent warm air proximate the top exterior surface of the refrigerator from being drawn around the front uppermost edge of the refrigerator and impinging on the air curtain as the air curtain leaves the air outlet, because the air guide forms a barrier that extends from the air outlet and the air curtain is no longer proximal to the warm air. An advantage of the air guide only bypassing a portion of the void is that the air curtain follows the intended path more closely and users can easily see and access items on the top angled shelf.

Although the air guide 12 shown in Fig. 3 shows an air guide wherein the air guide outlet is offset away from, or is offset distal to, the rear wall of the refrigerated storage space with respect to the air guide inlet, other air guides may be used to achieve the same technical effect. For example, an air guide comprising an air guide inlet through which the air enters and an air guide outlet at which the air curtain is established, wherein the air guide outlet is aligned, or is substantially aligned, with the air guide inlet, may be used. In other embodiments, the body of the air guide may have a chicane shape or an "S" shape. The chicane shape or the "S" shape may be made up of a curve in a first direction and a curve in a second direction. Alternatively, the body of the air guide may comprise a single curve. In some embodiments a part of the air guide may extend into the duct. In particular, an outermost side or a distal side (with respect to the refrigerated interior) of the air guide may extend into the duct. A technical advantage of all of these configurations is that the air guide can be better customised to work with the air flow characteristics of different fridges.

A cross sectional area of the air guide inlet of the air guide 12 shown in Fig. 3 is substantially the same as a cross sectional area of an air guide outlet. Air guides with different cross-sectional areas may also be used, for example an air guide wherein a cross sectional area of the air guide inlet is larger than a cross sectional area of an air guide outlet may be used. Alternatively, an air guide wherein a cross sectional area of the air guide inlet is smaller than a cross sectional area of an air guide outlet may also be used.

The air guide 12 may be coupled to the refrigerator using any of screws, rivets, mastic, adhesive or any other way of attachment known to the person skilled in the art.

Figure 4 shows a method of selecting an air guide from a plurality of air guides for use with an open display refrigerator, wherein the open display refrigerator comprises a refrigerated storage space, air in the refrigerated storage space being separated from air exterior to the open display refrigerator by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet and wherein the method comprises: providing an array of temperature sensors within an interior of the open display refrigerator 100;

measuring an initial temperature difference between the warmest temperature recorded by the array of temperature sensors and the coldest temperature recorded by the array of temperature sensors 101; coupling one or more air guides to the air outlet or air duct such that the or each air guide extends from the air outlet and bypasses a portion of a void between the uppermost shelf and the air outlet, whereby the air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet 102; measuring a respective final temperature difference associated with the or each air guide, the or each final temperature difference being the temperature difference between the warmest temperature recorded by the array of temperature sensors and the coldest temperature recorded by the array of temperature sensors after the associated air guide has been coupled to the air outlet or air duct 103; selecting an air guide from the one or more air guides, whereby the difference between the initial temperature difference and the final temperature difference associated with the selected air guide is at least a threshold temperature difference, or selecting the air guide from the one or more air guides for which the difference between the initial temperature difference and the associated final temperature difference is greatest 104.

In some embodiments, the array of temperature sensors are provided within the refrigerated storage space. In some embodiments, a temperature sensor of the array of temperature sensors is provided proximate the air inlet. In some embodiments the air guide, and hence the path of the air curtain, is adjusted such that the temperature difference is further reduced.

In some embodiments, the method may include steps that comprise measuring the temperature by placing numerous jelly-bricks (examples of jelly-bricks known in the art are Tylose packs or M-Packs) on the shelves of the refrigerator, wherein each jelly-brick has its own temperature probe, each of which makes up the array of temperature probes, so that the temperature at different points in the fridge can be tracked. As the location of the warmest jelly-brick and the location of the coolest jelly-brick may change with the addition of the air guide and/or adjustments made to the air guide, the difference between the warmest jelly-brick and the coolest jelly brick may be measured as opposed to measuring the same jelly-bricks before and after adding or adjusting the air guide.