WO2008150297A1

WO2008150297A1 - Air cooled display case shelf

Info

Publication number: WO2008150297A1
Application number: PCT/US2007/070705
Authority: WO
Inventors: Charles R. Schenk; Neelkanth S. Gupte
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2007-06-08
Filing date: 2007-06-08
Publication date: 2008-12-11
Anticipated expiration: 2009-12-08
Also published as: US20100192600A1; CA2688177A1

Abstract

A refrigerated display case is provided that includes a display chamber for displaying product. The display chamber includes a product tray for supporting the product. A cooling chamber is arranged beneath the product and is in communication with a surface of the product tray. The cooling chamber is sealed from the display chamber, in one example, and includes a cooling coil. A fan is in communication with the cooling chamber and cooling coil. The fan circulates a cooling flow through the cooling coil. The cooling flow moves across the surface and absorbs` heat from the product tray by convection. The cooled product tray removes heat from the product by conduction.

Description

AIR COOLED DISPLAY CASE SHELF

BACKGROUND OF THE INVENTION

This application relates to a refrigerated display case for refrigerating and displaying food products.

Refrigerated display cases are used to refrigerate and display products such as meat at a grocery store. The products are displayed to customers in a display chamber that is cooled by a gravity coil. The gravity coil cools the product by buoyancy circulation in which the cooled air produced by the gravity coil moves downward toward the product as it becomes more dense. As the cooled air absorbs heat from the product, the warmed air rises toward the gravity coil where it is again cooled. In this manner, cooled air is circulated within the display chamber without the use of a fan, which would undesirably dry the product.

The product is supported on a product tray. A serpentine coil is arranged in a cooling chamber beneath the product tray. The serpentine coil and gravity coil are connected in series. The serpentine coil has no fins and typically extends along the length of the display case. The serpentine coil is not permitted to touch the product tray since its temperature is much colder than freezing. The serpentine coil simply removes any heat gain attributable to the lower portion of the display case to prevent heat gain in the product. The majority of the refrigerant load is associated with the gravity coil, which results in an unbalanced, inefficient refrigeration system.

What is needed is a refrigerated display case that improves heat removal from the products while balancing and reducing the overall refrigeration load on the refrigerant system. Furthermore, it is desired that the refrigeration system avoid drying the product.

SUMMARY OF THE INVENTION

A refrigerated display case is provided that includes a display chamber for displaying product. The display chamber includes a product tray for supporting the product. A cooling chamber is arranged beneath the product and is in communication with a surface of the product tray. The cooling chamber is sealed from the display chamber, in one example, and includes a cooling coil. A fan is in communication with the cooling chamber and cooling coil. The fan circulates a cooling flow through the cooling coil. The cooling flow moves across the surface and absorbs heat from the product tray by convection. The cooled product tray removes heat from the product by conduction.

These and other features of the application can be best understood from the following specification and drawings, the following of which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic, cross-sectional view of an example refrigerated display case. Figure 2 is a schematic view of a refrigerant system used to cool the display case shown in Figure 1.

Figure 3 is a schematic, cross-sectional view of another example refrigerated display case.

Figure 4 is a cross-sectional view of a portion of a cooling coil for use in the refrigerated display case.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A refrigerated display case 10 is shown in Figures 1 and 3. The display case 10 includes a display chamber 12 used for supporting products 14, such as meat.

The display chamber 12 includes a display window 16 through which customers view the products 14. The display chamber 12 is accessible through access panels

18 opposite the display window 16. Typically, an air curtain device 22 that includes a fan 24 blows an air curtain A across the display window 16 to minimize the heat transfer to the display chamber 12 through the display window 16. An example refrigerant system 26 is schematically shown in Figure 2. The refrigerant system 26 includes a gravity coil 36 (also shown in Figures 1 and 3) arranged in the display window 16. The gravity coil 36 cools the products 14 by radiation thereby generating a buoyancy circulation B, which is shown in Figure 3. As the air display chamber 12 cools and becomes more dense, it flows to the bottom of the display chamber 12 where it removes heat from the products 14. As the cooled air absorbs heat, it rises to the gravity coil 36 where it is again cooled. In this manner, the products 14 are cooled without the use of a fan, which would undesirably dry the products 14. Returning to Figure 2, the refrigerant system 26 includes a compressor 28 that receives the refrigerant from the gravity coil 36. The compressed refrigerant flows to a heat exchanger 30 from which heat is rejected to an outside environment. Refrigerant flows from the heat exchanger 30 to an expansion device 32, for example, that expands thereby producing cooled refrigerant. The expanded refrigerant flows to a cooling coil 46 before flowing to the gravity coil 36.

Typically the compressor 28 and heat exchanger 30 are located outside the refrigerated display case 10, and the expansion device 32, cooling coil 46 and gravity coil 36 are located within the display case 10. However, it should be understood that the components of the refrigerant system 26 can be located in any suitable location and manner. Moreover, one or more temperature sensors may be used to communicate temperature information from various locations within the display case 10 to provide a feedback system and accurately refrigerate the display case 10.

Returning to Figure 1, a cooling chamber 38 is provided beneath the display chamber 12 and is supported by a base 20. The products 14 are supported on a product tray 40 that separates the display chamber 12 and cooling chamber 38. In one example, the product tray 40 seals the cooling chamber 38 to prevent undesired air flow from entering the display chamber 12 from the cooling chamber 30, which would undesirably dry the products 14. Typically, a foam barrier 42 is used at the bottom of the cooling chamber 38 and is supported by the base 20 to minimize heat transfer from the outside environment into the cooling chamber 38.

In the example, a fan 44 is utilized to generate a cooling flow F within in the cooling chamber 38. The cooling flow F cools the product tray 40 by convection, which in turn cools the products 14 by conduction. In this manner, the cooling coil 46 operates to provide significant cooling to the products 14 instead of simply acting as a heat sink to prevent heat transfer to the products 14 from the bottom of the display case 10, as in the prior art. In one example, the cooling coils 46 include fins 48, which is shown in

Figure 4. The fins 48 increase the heat transfer to the cooling coils 46 from the cooling flow F as it picks up heat from the products 14 through the product tray 40. A baffle 50 is used in the example shown in Figure 1 to guide the cooling flow F horizontally along a lower surface of the product tray 40 (generally parallel) to maximize convection cooling to the product tray 40.

Another example arrangement is shown in Figure 3. In the example shown, the fan 44 is arranged between coils 46. A baffle 50 is associated with each coil 46.

The cooling flow F moves laterally outward from the fan 44 to the front and rear of the cooling chamber 38 before returning through the respective coils 46. The coils 46 shown in Figure 3 may be parallel, lateral lengths of the same coil, for example.

Although example embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.

Claims

1. A refrigerated display case comprising: a display chamber having a product tray for supporting product; a cooling chamber in communication with the product tray, the cooling chamber including a cooling coil; and a fan in communication with the cooling chamber and cooling coil for generating an air flow across a surface of the product tray to remove heat therefrom.

2. The refrigerated display case according to claim 1, wherein the fan generates a horizontal cooling flow across the product tray, the cooling chamber arranged beneath the product tray.

3. The refrigerated display case according to claim 2, comprising a baffle arranged in the cooling chamber, the baffle directing the cooling flow across the surface of the product tray.

4. The refrigerated display case according to claim 3, wherein the fan blows the cooling flow generally parallel to the baffle.

5. The refrigerated display case according to claim 3, wherein the fan blows the cooling flow generally parallel to the product tray.

6. The refrigerated display case according to claim 5, wherein the fan is arranged between first and second coils, first and second baffles associated with each of said first and second coils, first and second cooling flows generated from the fan in opposing directions respectively through first and second coils and returning to said fan.

7. The refrigerated display case according to claim 1, wherein the product tray is sealed relative to the display chamber.

8. The refrigerated display case according to claim 1, wherein the cooling flow generates convection cooling of the product tray.

9. The refrigerated display case according to claim 8, wherein the convection cooling generates conduction cooling of product on the product tray.

10. The refrigerated display case according to claim 1, comprising a gravity coil arranged in the display chamber, the gravity coil generating radiation cooling providing a buoyancy circulation within the display chamber.

11. The refrigerated display case according to claim 1 , comprising a refrigerant system that includes the cooling coil and a gravity coil arranged within the display chamber, a refrigerant from the cooling coil and gravity coil flowing to a compressor arranged upstream from a heat exchanger, the refrigerant from the heat exchanger flowing to an expansion device before being received by the cooling coil.

12. A method of refrigerating a product comprising the steps of: supporting a product within a display chamber using a product tray; generating a convection cooling on a surface of the product tray separated from the product; and cooling the product with conduction cooling from the product tray.

13. The method according to claim 12, comprising the step of generating a cooling flow in a cooling chamber arranged beneath the product tray.

14. The method according to claim 13, comprising blowing the cooling flow across a cooling coil.

15. The display case according to claim 1, wherein the cooling coil includes fins.

16. The display case according to claim 1, wherein the display chamber includes a display window providing visual access to the product within the display chamber.