WO2007053148A1

WO2007053148A1 - Refrigerated merchandiser and shelf therefor

Info

Publication number: WO2007053148A1
Application number: PCT/US2005/040017
Authority: WO
Inventors: Neelkanth Shridhar Gupte
Original assignee: Carrier Corroration
Priority date: 2005-11-04
Filing date: 2005-11-04
Publication date: 2007-05-10

Abstract

A refrigerated merchandiser (10) includes a display case defining a product display space (30) and having at least one shelf (18) disposed within the product display space. The shelf has a top side for supporting refrigerated items thereon and an under side. A heat transfer device (74, 80) is disposed in heat exchange relationship against the underside of the shelf to transfer heat from product on the front portion (18F) of the shelf to product on the rearward portion (18F) of the shelf thereby further cooling the product disposed on the front portion of the shelf.

Description

REFRIGERATED MERCHANDISER AND SHELF THEREFOR

BACKGROUND OF THE INVENTION

[0001] This invention relates in general to refrigerated merchandisers and, more particularly, to augmenting product cooling in refrigerated display cases having one or more shelves for support product.

[0002] Refrigerated merchandisers, also known as refrigerated display cases, are commonly used in supermarkets, convenience stores and other food service establishments to display product in a refrigerated environment. Such display cases have an access opening, which may or not have a door, through which consumers may reach into the display case to retrieve refrigerated product. Product is stored on a plurality of generally horizontally extending, vertically spaced shelves disposed within the display case. Refrigerated air is circulated through the product display area by a fan housed in an equipment compartment generally located beneath the product display area. The fan draws air from the product display area through an air return inlet at the lower front of the product display area, into the equipment compartment, thence through an evaporator and into a refrigerated air supply duct that extends vertically along the rear of the product display area. A portion of this refrigerated air passes directly into the product display area through an array of openings in a rear panel separating the air supply duct from the product display area. The remainder of the refrigerated air passes upwardly through the air supply duct and thence through a generally horizontal duct extending forwardly atop the product display air to an air outlet in the upper front of the product display area. The refrigerated air is drawn downwardly from the air outlet across the open front viewing area of the product display area to return through the air return inlet into the equipment compartment. In this manner, a downwardly flowing air curtain is formed that extends from near the top to near the bottom of the display case over the entire width of the product display area.

[0003] On open front display cases, the primary function of the air curtain is to provide a barrier to hinder the infiltration of warm ambient air from the environment in front of the display case, typically the customer service area of a supermarket, convenience store or other food service establishment. However, the air curtain is subiect to disruption, for example by a customer reaching into the product display area to retrieve an item for purchase. When the air curtain is disturbed, warm air infiltrates the air curtain and passes into the product display area. On display cases having a door covering the access opening, warm air enters the product display region when a customer opens the door to retrieve product, and often holds the door open while selecting the product. Additionally, heat may be transferred into the product display area through the viewing area, whether open or doored, by radiation from lighting and other heat sources within the customer service area. This infiltration of warm air and the radiant heat transfer, as well as heat from display case lighting typically disposed along the upper front and/or front sides of the product display area, result in an increase in the air temperature and product temperature in the forward region of the display case.

[0004] As the refrigerated air passing from the refrigerated air supply duct through the array of openings in the rear panel at the back of the product display area passes forwardly therethrough, the refrigerated air passes over and cools the product on the shelves within the product display area. The refrigerated air entering the product display area through the openings in the rear panel is also drawn by the air circulating fan as it passes forwardly through the product display area to and through the air return inlet to return to the equipment compartment.

[0005] Consequently, in such prior art display case merchandisers, in addition to being subject to warm air infiltration and radiant heat, product on the respective forward sections of the shelves does not receive the full cooling benefit of the refrigerated air. Thus, in such prior art display case merchandisers, product stored on the forward region of the shelves is often warmer than product stored on the rearward portion of the shelves. This non-uniformity in product temperature is undesirable as product in the forward region of the product display case will be insufficiently cooled when product in the rearward region of the display case is cooled to the desired temperature. To compensate, it is known to further lower the temperature of the refrigerated air entering the product display area by decreasing the temperature of the refrigerant passing through the evaporator cooling the refrigerated air. However, when doing so, the product in the rearward region of the display case will be over cooled when product in the forward region of the display case is cooled to the desired temperature. Further, with the lower refrigerant temperatures, frost formation on the evaporator tube coil may be aggravated. [0006] A need therefore exists for augmenting the cooling of product stored on the front section of the shelves in the forward portion of the refrigerated display case, in an energy efficient manner without overcooling product on the shelves in the rearward portion of the display case and without aggravating frost formation on the evaporator tube cool.

SUMMARY OF THE INVENTION

[0007] It is a general object of the invention to augment the cooling of product in a refrigerated merchandiser to minimize the variation in product temperature of product in the front portion of the display case versus product in the rearward portion of the display case of the merchandiser.

[0008] It is an object of one aspect of the invention to provide a refrigerated merchandiser having a heat transfer device operatively associated with one or more shelves for augmenting the cooling of product on the forward portion of the shelf or shelves.

[0009] In one aspect of the invention, a refrigerated merchandiser includes a display case defining a product display space and having at least one shelf disposed within the product display space. The shelf has a top side for supporting refrigerated items thereon and an under side. A heat transfer device is disposed in heat exchange relationship against the underside of the shelf. A circulator pump is operatively associated with the heat exchange tube coil for circulating a heat exchange working fluid through the heat exchange tube coil. In an embodiment, the heat transfer device is a heat exchange tube coil. In an embodiment, the heat transfer device is a serpentine heat exchange tube coil. In a further embodiment, the heat transfer device is a serpentine heat exchange tube coil having a first series of loops disposed against the underside of a rearward portion of the shelf and a second series of loops disposed against the underside of a forward portion of the shelf, the second series of loops being more closely spaced than the first series of loops. In another embodiment, the heat transfer device is a plurality of heat pipes disposed in heat exchange relationship against the underside of the shelf. The plurality of heat pipes is disposed in laterally spaced relationship and extending from a forward region of the shelf to a rearward portion of the shelf. [0010] In another aspect of the invention, a shelf is provided including a product support member having a top side for supporting refrigerated food items and an under side, and a heat transfer device disposed in heat exchange relationship against the under side of the support member. In an embodiment, the heat transfer device is a heat exchange tube coil. Li an embodiment, the heat transfer device is a serpentine heat exchange tube coil. In a further embodiment, the heat transfer device is a serpentine heat exchange tube coil having a first series of loops disposed against the underside of a rearward portion of the shelf and a second series of loops disposed against the underside of a forward portion of the shelf, the second series of loops being more closely spaced than the first series of loops. In another embodiment, the heat transfer device is a plurality of heat pipes disposed in heat exchange relationship against the underside of the shelf. The plurality of heat pipes is disposed in laterally spaced relationship and extending from a forward region of the shelf to a rearward portion of the shelf.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment with reference to the accompany drawings wherein:

[0012] FIG. 1 is a side elevation view, partly in section, of an exemplary embodiment of a refrigerated merchandiser having an open-front display case with augmented cooling in accord with the invention;

[0013] FIG. 2 is a perspective view of an exemplary embodiment of the augmented cooling system of the refrigerated display case of FIG. 1;

[0014] FIG. 3 is a plan view illustrating an exemplary embodiment of a shelf with augmented cooling in accord with the present invention;

[0015] FIG. 4 is a plan view illustrating an alternate exemplary embodiment of a shelf with augmented cooling in accord with the present invention;

[0016] FIG. 5 is a sectioned side elevation view taken along line 5-5 of FIG. 4; and [0017] FIG. 6 is a side elevation view taken along line 6-6 of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] The invention will be described hereinafter in application on a refrigerated merchandiser having a display case with an open-front access. It is to be understood, however, that the invention may also be applied to refrigerated merchandisers having a display case equipped with a door or doors covering a front access. Referring now to Figures 1 and 2, the refrigerated merchandiser 10 includes an outer cabinet 12 and an inner cabinet liner 20 that defines within its bounds an open-front product display region 30. The outer cabinet has a base 13, a rear wall 14 extending upwardly from the back of the base, a top wall 15 extending forwardly from the rear wall and a pair of side walls 16 extending vertically from the base to the top wall 15 and forwardly from the rear wall 13. Each of the cabinet base 13, rear wall 14, top wall 15 and side walls 16 is insulated, as in conventional practice, to thermally isolate the interior of the cabinet 12, including the product display region 30, from excessive heat transfer therethrough. [0019] Perishable product 80 may be displayed on shelves 18 disposed within the product display region 30. The product display region 30 has an open front 25 so as to permit consumers to not only view, but also reach into the product display region 30 to select and remove items of product 80 that they desire to purchase. Product display region 30 is cooled in a conventional manner to a desired product temperature, typically to a temperature between 32°F to less than about 4O⁰F, depending upon what product is being merchandised therein, for example, perishable comestibles, such as meats, poultry, fish, diary products, prepackaged foods, or beverages, such as for example bottled or canned soda, milk, water, juices, fruit drinks, beer and other drink, or other products that need to be maintained in a controlled environment.

[0020] The inner cabinet liner 20 includes a bottom panel 24, a back panel 26, and a top panel 28. A refrigeration compartment 40 is provided beneath the product display region 30 between the base 13 and the bottom panel 24, wherein components of the refrigerant system, typically an evaporator 50 and an air mover 60, such as for example one or more fans, are housed. However, it is to be understood that the specific type of air mover employed is not relevant The back panel 26 and the ton «?jiel 28 are disposed in spaced relationship, respectively, with the back wall 14 and the top wall 15 to form a refrigerated air supply duct 32 therebetween extending upwardly behind the back panel 26 and thence horizontally above the top panel 28 and opening to the product display space 30 through air outlet 34 at the front of the display case 10. [0021] In the evaporator 50, which may, for example, comprise a conventional tube heat exchanger, with or without fin surface, the refrigerant passes in heat exchange relationship with air drawn from the product display space 30 through air inlet 42 at the lower front of the display case 10. The evaporator 50 is connected in fluid flow communication with a condenser (not shown) and a compressor (not shown) in a conventional closed-loop vapor compression cycle circuit. The condenser and compressor may be located remotely from the refrigerated display case 10, as for example in conventional supermarket applications wherein the respective evaporators of a plurality of display cases located throughout the customer service area of the supermarket are serviced by a common compressor or bank of compressors housed in a separate area of the supermarket and one or more condensers located externally of the building. However, it is to be understood that the present invention may also be employed on standalone refrigerated merchandisers that include their own refrigeration unit for providing the cold refrigerant to the evaporator. In stand alone merchandisers, the compressor and condenser may be housed in a separate section of the equipment compartment 40 thermally isolated from the evaporator and from the product display space 30.

[0022] As mentioned hereinbefore, the air circulation duct 32 is formed between the rear wall 14 and the top wall 15 of the outer cabinet 12 and the back panel 26 and top panel 28, respectively, of the inner cabinet liner 20. Air mover 60 serves to draw air from the product display region 30 through air inlet 42 through the compartment 40 so as to traverse evaporator 50, and thence into and through the air supply duct 32. As in conventional practice, the air passing through the equipment compartment 40 traverses the evaporator 50, passing in heat exchange relationship with chilled refrigerant in the evaporator 50, and is thereby cooled to a desired temperature. A portion of the refrigerated cooling air passes through an air outlet 34 at the upper front of the display cabinet 10. Another portion passes directly into the product display region 30 from the air supply duct 32 through an array of a plurality of openings 22 provided in the back panel 26. The particular shape, size, number and arrangement of the openings 22 through the back panel 34 are not germane to the invention.

[0023] From the air outlet 34, the cool refrigeration air is directed downwardly along path 45 across the open front of the product display region space 30 to air inlet 42. Thus, the refrigerating air is recycled and repeatedly circulated through the equipment compartment 40 and thence to duct 32 to converse energy expended in cooling the refrigeration air. Further, through the afore-described cooling arrangement, a cool air curtain is formed across the open-front product display region 30 from top to bottom thereof. The refrigerating air entering the product display space 30 through the openings 22 in the back panel 26 is also drawn by the air mover 60 back through the air inlet 42 into the compartment 40 to be chilled and passed back into air supply duct 32. [0024] As noted hereinbefore, although such an air curtain is effective to hinder infiltration of ambient air into the product display space, the air curtain is subject to disruption, for example by a customer reaching into the product display space 30 to retrieve an item of product 80 for purchase. Additionally, heat may be transferred into the product display space 30 by radiation from lighting and other heat sources within the customer service area. In addition to being subject to warm air infiltration and radiant heat, product on the respective forward regions of the shelves 18 will not receive the full cooling benefit of the refrigerated air entering through the openings 22 in the back panel 26. Therefore, a non-uniformity in product temperature, i.e. the product on the forward portion 18F of the shelves 18, being in the forward region of the product display space 30, being warmer than the product on the rearward portion 18R of the shelves 18, being in the rearward portion of the product display space 30, typically exists in prior art display cases.

[0025] Referring now to FIG. 1, FIG. 2, and FIG. 3, in accord with the invention, a heat transfer circuit 70 is provided in operative association with the shelves 50 to augment the cooling of product stored on the shelves 18. The heat transfer circuit 70 includes at least one circulator pump 72 and at least one heat transfer coil 74 operatively associated with at least one of the shelves 18. In the exemplary embodiment of the invention depicted herein, the heat transfer circuit 70 includes a single circulator r"!™p operatively associated with four heat transfer coils, with a heat transfer coil 74 mounted in abutting relationship with the underside of each shelf 18. Each heat transfer coil 74 extends from a rearward portion 18R of its associated shelf 18 to a forward portion 18F of that shelf, and from side to side, thereby effectively covering a substantial portion of the shelf in heat transfer relationship. The circulator pump 72 operates to circulate a heat transfer working fluid, such as for example glycol, water or other suitable working fluid, through supply line 73 to and through each of the heat transfer coils 74, with the working fluid passing through each heat transfer coil 74 from the rearward to the forward, and thence through return line 75 to return to the pump 72. However, it is to be understood that in some applications, not all shelves will be provided with an associated heat transfer coil. Further, each heat transfer coil 74 may have its own dedicated circulator pump 72, rather than having a single circulator pump serving a plurality of heat transfer coils as in thee depicted embodiment.

[0026] To enhance heat transfer at the forward portion 18F of the shelf 18, the loops of the heat transfer coil 74 have may be more closely spaced together at the forward portion 18F of the shelf 18. For example, as best seen in Figure 3, the loops 78 of the coil 74 associated with the forward portion 18F of the plate 18 are relatively closely spaced, while the loops 76 of the coil 74 associated with the rearward portion 18R of the plate 18 are more widely spaced. The more closely spaced loops 78 have a relatively smaller channel width, w, between adjacent refrigerant passes, and the more widely spaced loops 76 have a relatively larger channel width, W, between adjacent refrigerant passes. Heat transfer from the product on the forward portion 18F of the shelf 18 to the working fluid may be selectively optimize for a particular application by selection of the channel width, w, between adjacent passes of the loops 78 and by selectively adjusting the flow rate of the working fluid circulating through the heat transfer circuit 70. The smaller the channel width, w, and the larger the flow rate, the greater the amount of heat transfer from the product on the forward portion of the shelf 18 to the working fluid flowing through the loops 78, and thence to the product on the rearward portion 18R of the shelf. As those skilled in the art will appreciate, the channel width and the flow rate may be selected to optimize the heat transfer from products at the forward portion 18F of a shelf 18 to the products at the rearward portion 18R of that respective shelf 18 so as to at least minimize, if not eliminate, any non-uniformity in product temperature from the rear to the front of the product display space 30. As the products at the rearward portion 18R of the shelf are more effectively cooled by the refrigerated air passing through the openings 22 in the rear panel 26, the transfer of heat from the products at the forward portion 18F of the shelf to the products at the rearward portion 18R of the shelf will not significantly increase the temperature of those products.

[0027] The product cooling augmentation system of the invention may be used in connection plate-type shelves or wire-grid type shelves. With either type of shelf, heat transfer may be enhanced by forming the shelf from a material having good thermal conductivity, such as for example aluminum or copper, which would also be compatible with aluminum or copper tube heat transfer coils for purposes of mounting the heat transfer coil to underside of the shelf.

[0028] Referring now to FIGS. 4, 5 and 6, an alternate embodiment of the invention is depicted wherein a plurality of heat pipes 80 are mounted in heat transfer relationship with the underside of shelf 18. The plurality of heat pipes 80 extend in generally parallel, laterally spaced relationship from near the rear edge to near the front edge of the shelf 18. Each heat pipe 80 comprises a copper or aluminum tube having internal grooves formed on its inside surface as in conventional practice. After the interior of the heat pipe is evacuated, a small amount of suitable working fluid, for example R-22 refrigerant, is injected into the interior of tube and the tube sealed. In operation, evaporation of the working fluid occurs within that portion 82 of each heat pipe 80 that extends along the underside of the forward portion 18F of the shelf 18, while condensation of the working fluid occurs within that portion 84 of each heat pipe 80 that extends along the underside of the rearward portion 18R of the shelf 18. The working fluid condensing in rear portion 84 of the heat pipe passes along the internal grooves (not shown) back to the forward portion 82 of the heat pipe wherein the working fluid is again evaporated. As the working fluid evaporates, it draws heat from the product disposed on the forward portion 18F of the shelf thereby further cooling that product. The fluid condenses in the rear portion 84 of the heat pipe 80 thereby transferring heat from the product on the forward portion 18F of the shelf to the product on the rearward portion 18R of the shelf. Again, as the products at the rearward portion 18R nf the shelf are mere effectively cooled by the refrigerated air passing through the openings 22 in the rear panel 26, the transfer of heat from the products at the forward portion 18F of the shelf to the products at the rearward portion 18R of the shelf will not significantly increase the temperature of those products.

[0029] It is to be understood that the exemplary embodiments described and depicted herein may also be applied to other types of refrigerated merchandisers. Further, those of ordinary skill in the art will, in light of the disclosure, recognize that various modifications may be made to the invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A refrigerated merchandiser for displaying refrigerated food items comprising: a display case defining a product display space; at least one shelf disposed within the product display space, said at least one shelf having a topside for supporting refrigerated items thereon and an underside; and a heat transfer device disposed in heat exchange relationship against the underside of said at least one shelf.

2. A refrigerated merchandiser as recited in claim 1 wherein said heat transfer device comprises a heat exchange tube coil.

3. A refrigerated merchandiser as recited in claim 2 further comprising a circulator pump operatively associated with said heat exchange tube coil for circulating a heat exchange working fluid through said heat exchange tube coil.

4. A refrigerated merchandiser as recited in claim 1 wherein said heat transfer device comprises a serpentine heat exchange tube coil.

5. A refrigerated merchandiser as recited in claim 4 wherein said serpentine heat exchange tube coil has a first series of loops disposed against the underside of a rearward portion of said at least one shelf and a second series of loops disposed against the underside of a forward portion of said at least one shelf, the second series of loops being more closely spaced than the first series of loops.

6. A refrigerated merchandiser as recited in claim 5 further comprising a circulator pump operatively associated with said serpentine heat exchange tube coil for circulating a heat exchange working fluid through said serpentine heat exchange tube coil from an inlet to the first series of loops to an outlet to the second series of loops.

7. A refrigerated merchandiser as recited in claim 1 wherein said heat transfer device comprises a plurality of heat pipes disposed in heat exchange relationship against the underside of said at least one shelf , said plurality of heat pipes disposed in laterally spaced and extending from a forward region of the shelf to a rearward portion of the shelf.

8. A shelf for a refrigerated merchandiser comprising: a product support member having a top side for supporting refrigerated food items and an underside; and a heat transfer device disposed in heat exchange relationship against the underside of said support member.

9. A shelf as recited in claim 8 wherein said heat -transfer device comprises a heat exchange tube coil.

10. A shelf as recited in claim 9 further comprising a circulator pump operatively associated with said heat exchange tube coil for circulating a heat exchange working fluid through said heat exchange tube coil.

11. A shelf as recited in claim 8 wherein said heat transfer device comprises a serpentine heat exchange tube coil.

12. A shelf as recited in claim 11 wherein said serpentine heat exchange tube coil has a first series of loops disposed against the underside of a rearward portion of said support member and a second series of loops disposed against the underside of a forward portion of said support member, the second series of loops being more closely spaced than the first series of loops.

13. A shelf as recited in claim 12 further comprising a circulator pump operatively associated with said serpentine heat exchange tube coil for circulating a heat exchange working fluid through said serpentine heat exchange tube coil from an inlet to the first series of loops to an outlet to the second series of loops.

14. A shelf as recited in claim 8 wherein said heat transfer device comprises a plurality of heat pipes disposed in heat exchange relationship against the underside of said at least one shelf, said plurality of heat pipes disposed in laterally spaced and extending from a forward region of the shelf to a rearward portion of the shelf.