Title:
Refrigerator with system for controlling drawer temperatures
Kind Code:
A1


Abstract:
A refrigerator is provided with a refrigerated compartment comprising one or more zones in thermal communication with each other and with each zone independently controlled and operated at a particular temperature. Each zone temperature is controlled by a separate evaporator or heat exchanger. A method for maintaining different temperatures in one or more zones in thermal communication with one another in a refrigerator is also provided.



Inventors:
Lyvers, Daniel (Cordova, TN, US)
Fontecchio, Joseph C. (Cordova, TN, US)
Gamblin, Tonya (Memphis, TN, US)
Rendel, Robert (Cordova, TN, US)
Sylvester, John (Haughton, LA, US)
Application Number:
10/897640
Publication Date:
01/26/2006
Filing Date:
07/23/2004
Primary Class:
International Classes:
F25D17/04; F25B41/00; F25B49/00
View Patent Images:



Primary Examiner:
ABDUR RAHIM, AZIM
Attorney, Agent or Firm:
WOMBLE BOND DICKINSON (US) LLP (ATTN: IP DOCKETING P.O. BOX 7037, ATLANTA, GA, 30357-0037, US)
Claims:
We claim:

1. A refrigerator comprising: a first zone and a second zone wherein the first zone is disposed within the second zone; a refrigeration system comprising a first evaporator and a second evaporator connected in series and a refrigerant, the first evaporator cooling the first zone to a first temperature, the second evaporator cooling the second zone to a second temperature, and the refrigerant proceeding through the first condenser and through the second condenser; wherein the first evaporator has a first evaporator volume and the second evaporator has a second evaporator volume; wherein the first evaporator volume is different than the second evaporator volume; and wherein the first temperature is different than the second temperature.

2. The refrigerator of claim 1, wherein the refrigeration system further comprises a compressor, a condenser, a first expansion valve, a first fan for providing air flow over the first evaporator, and a second fan for providing air flow over the second evaporator.

3. The refrigerator of claim 2, wherein the refrigerant flows continuously through the first expansion valve, through the first evaporator, through the second evaporator, through the compressor, through the condenser, and returns to the first expansion valve.

4. The refrigerator of claim 1, wherein the refrigeration system further comprises a thermostatic controller.

5. The refrigerator of claim 1, wherein the first temperature and the second temperature are above-freezing.

6. The refrigerator of claim 1, wherein the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature.

7. The refrigerator of claim 1, wherein the refrigeration system is capable of maintaining the first temperature from 4° F. to 7° F. lower than the second temperature.

8. The refrigerator of claim 1, wherein the first zone comprises at least one drawer.

9. The refrigerator of claim 1, wherein: the second evaporator is in air flow communication with the second zone by a second zone air inlet through which air enters the second zone, and a second zone air outlet through which air exits the second zone; and the second zone air inlet is situated above the second zone air outlet.

10. The refrigerator of claim 1, wherein: the first evaporator is in air flow communication with the first zone by a first zone air inlet through which air enters the first zone, and a first zone air outlet through which air exits the first zone; and the first zone air inlet is situated below the first zone air outlet.

11. The refrigerator of claim 1, wherein: the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature; the first evaporator is in air flow communication with the first zone by a receiving duct through which air exits the first zone, a distributing duct through which air enters the first zone, and a first evaporator fan in air flow communication with the receiving duct and the distributing duct; and the first evaporator can be housed in either the receiving duct or the distributing duct.

12. The refrigerator of claim 1, wherein the first evaporator volume is smaller than the second evaporator volume.

13. The refrigerator of claim 1, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils have a second internal diameter and the first evaporator coils have a first internal diameter; and wherein the second internal diameter is larger than the first internal diameter.

14. The refrigerator of claim 13, wherein the second evaporator coils are longer than the first evaporator coils.

15. The refrigerator of claim 1, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils are longer than the first evaporator coils.

16. The refrigerator of claim 1, further comprising a second expansion valve located between the first evaporator and second evaporator.

17. A refrigerator comprising: a first zone and a second zone; a refrigeration system comprising a first evaporator and a second evaporator connected in series and a refrigerant, the first evaporator cooling the first zone to a first temperature, the second evaporator cooling the second zone to a second temperature, and the refrigerant proceeding through the first condenser and through the second condenser; wherein the first evaporator has a first evaporator volume and the second evaporator has a second evaporator volume; wherein the first evaporator volume is different than the second evaporator volume; wherein the first temperature is different than the second temperature; and wherein the first and second zone share at least one thermally conductive common wall.

18. The refrigerator of claim 17, wherein the refrigeration system further comprises a compressor, a condenser, a first expansion valve, a first fan for providing air flow over the first evaporator, and a second fan for providing air flow over the second evaporator.

19. The refrigerator of claim 18, wherein the refrigerant flows continuously through the first expansion valve, through the first evaporator, through the second evaporator, through the compressor, through the condenser, and returns to the first expansion valve.

20. The refrigerator of claim 17, wherein the refrigeration system further comprises a thermostatic controller.

21. The refrigerator of claim 17, wherein the first temperature and the second temperature are above-freezing.

22. The refrigerator of claim 17, wherein the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature.

23. The refrigerator of claim 17, wherein the refrigeration system is capable of maintaining the first temperature from 4° F. to 7° F. lower than the second temperature.

24. The refrigerator of claim 17, wherein the first zone is located below the second zone.

25. The refrigerator of claim 17, wherein the first zone is located above the second zone.

26. The refrigerator of claim 17, wherein the first zone comprises at least one drawer.

27. The refrigerator of claim 17, wherein: the second evaporator is in air flow communication with the second zone by a second zone air inlet through which air enters the second zone, and a second zone air outlet through which air exits the second zone; and the second zone air inlet is situated above the second zone air outlet.

28. The refrigerator of claim 17, wherein: the first evaporator is in air flow communication with the first zone by a first zone air inlet through which air enters the first zone, and a first zone air outlet through which air exits the first zone; and the first zone air inlet is situated below the first zone air outlet.

29. The refrigerator of claim 17, wherein: the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature; the first evaporator is in air flow communication with the first zone by a receiving duct through which air exits the first zone, a distributing duct through which air enters the first zone, and a first evaporator fan in air flow communication with the receiving duct and the distributing duct; and the first evaporator can be housed in either the distributing duct or the receiving duct.

30. The refrigerator of claim 17, wherein the first evaporator volume is smaller than the second evaporator volume.

31. The refrigerator of claim 17, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils have a second internal diameter and the first evaporator coils have a first internal diameter; and wherein the second internal diameter is larger than the first internal diameter.

32. The refrigerator of claim 31, wherein the second evaporator coils are longer than the first evaporator coils.

33. The refrigerator of claim 17, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils are longer than the first evaporator coils.

34. The refrigerator of claim 17, further comprising a second expansion valve located between the first evaporator and second evaporator.

35. A method for maintaining a first zone and a second zone of a refrigerator at different temperatures, the method comprising: cooling the first zone to a first temperature with a first evaporator; cooling the second zone to a second temperature with a second evaporator; wherein the first zone is disposed within the second zone; wherein the first evaporator and second evaporator are connected in series; wherein the first evaporator has a first evaporator volume and the second evaporator has a second evaporator volume; wherein the second evaporator volume is different than the first evaporator volume; and wherein the first temperature is different than the second temperature.

36. The method of claim 35, wherein the refrigeration system further comprises a compressor, a condenser, a first expansion valve, a first fan for providing air flow over the first evaporator, and a second fan for providing air flow over the second evaporator.

37. The method of claim 36, wherein the refrigerant flows continuously through the first expansion valve, through the first evaporator, through the second evaporator, through the compressor, through the condenser, and returns to the first expansion valve.

38. The method of claim 35, wherein the refrigeration system further comprises a thermostatic controller.

39. The method of claim 35, wherein the first temperature and the second temperature are above-freezing.

40. The method of claim 35, wherein the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature.

41. The method of claim 35, wherein the first zone comprises at least one drawer.

42. The method of claim 41, wherein the at least one drawer comprises one or more openings; and wherein the first air flow passes through the one or more openings to directly cool the at least one drawer.

43. The method of claim 42, wherein the first zone further comprises blocking means for closing the one or more openings; and wherein the first air flow does not pass through the at least one drawer when the one or more openings are blocked to indirectly cool the at least one drawer.

44. The method of claim 43, wherein a user can manipulate the blocking means to directly cool or indirectly cool the at least one drawer.

45. The method of claim 35, wherein: the second evaporator is in air flow communication with the second zone by a second zone air inlet through which air enters the second zone, and a second zone air outlet through which air exits the second zone; and the second zone air inlet is situated above the second zone air outlet.

46. The method of claim 35, wherein: the first evaporator is in air flow communication with the first zone by a first zone air inlet through which air enters the first zone, and a first zone air outlet through which air exits the first zone; and the first zone air inlet is situated below the first zone air outlet.

47. The method of claim 46, wherein the first zone comprises at least one drawer; wherein the drawer comprises one or more openings corresponding to the first zone air inlet; wherein the first zone air outlet comprises an opening located above the at least one drawer; and wherein the first air flow is maintained substantially within the at least one drawer.

48. The method of claim 35, wherein: the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature; the first evaporator is in air flow communication with the first zone by a receiving duct through which air exits the first zone, a distributing duct through which air enters the first zone, and a first evaporator fan in air flow communication with the receiving duct and the distributing duct; and the first evaporator can be housed in either the receiving duct or the distributing duct.

49. The method of claim 35, wherein the first evaporator volume is smaller than the second evaporator volume.

50. The method of claim 35, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils have a second internal diameter and the first evaporator coils have a first internal diameter; and wherein the second internal diameter is larger than the first internal diameter.

51. The method of claim 50, wherein the second evaporator coils are longer than the first evaporator coils.

52. The method of claim 35, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils are longer than the first evaporator coils.

53. The method of claim 35, further comprising a second expansion valve located between the first evaporator and second evaporator.

54. A method for maintaining a first zone and a second zone of a refrigerator at different temperatures, the method comprising: cooling the first zone to a first temperature with a first evaporator; cooling the second zone to a second temperature with a second evaporator; wherein the first and second zone share at least one thermally conductive common wall; wherein the first evaporator and second evaporator are connected in series; wherein the first evaporator has a first evaporator volume and the second evaporator has a second evaporator volume; wherein the second evaporator volume is different than the first evaporator volume; and wherein the second temperature is different than the first temperature.

55. The method of claim 54, wherein the refrigeration system further comprises a compressor, a condenser, a first expansion valve, a first fan for providing air flow over the first evaporator, and a second fan for providing air flow over the second evaporator.

56. The method of claim 55, wherein the refrigerant flows continuously through the first expansion valve, through the first evaporator, through the second evaporator, through the compressor, through the condenser, and returns to the first expansion valve.

57. The method of claim 54, wherein the refrigeration system further comprises a thermostatic controller.

58. The method of claim 54, wherein the first temperature and the second temperature are above-freezing.

59. The method of claim 54, wherein the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature.

60. The method of claim 54, wherein the first zone comprises at least one drawer.

61. The method of claim 60, wherein the at least one drawer comprises one or more openings; and wherein the first air flow passes through the one or more openings to directly cool the at least one drawer.

62. The method of claim 61, wherein the first zone further comprises blocking means for closing the one or more openings; and wherein the first air flow does not pass through the at least one drawer when the one or more openings are blocked to indirectly cool the at least one drawer.

63. The method of claim 62, wherein a user can manipulate the blocking means to directly cool or indirectly cool the at least one drawer.

64. The method of claim 54, wherein: the second evaporator is in air flow communication with the second zone by a second zone air inlet through which air enters the second zone, and a second zone air outlet through which air exits the second zone; and the second zone air inlet is situated above the second zone air outlet.

65. The method of claim 54, wherein: the first evaporator is in air flow communication with the first zone by a first zone air inlet through which air enters the first zone, and a first zone air outlet through which air exits the first zone; and the first zone air inlet is situated above the first zone air outlet.

66. The method of claim 65, wherein the first zone comprises at least one drawer; wherein the drawer comprises one or more openings corresponding to the first zone air inlet; wherein the first zone air outlet comprises an opening located above the at least one drawer; and wherein the first air flow is maintained substantially within the at least one drawer.

67. The method of claim 54, wherein: the refrigeration system is capable of maintaining the first temperature from 2° F. to 10° F. lower than the second temperature; the first evaporator is in air flow communication with the first zone by a receiving duct through which air exits the first zone, a distributing duct through which air enters the first zone, and a first evaporator fan in air flow communication with the receiving duct and the distributing duct; and the first evaporator can be housed in either the receiving duct or the distributing duct.

68. The method of claim 54, wherein the second evaporator volume is larger than the first evaporator volume.

69. The method of claim 54, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils have a second internal diameter and the first evaporator coils have a first internal diameter; and wherein the second internal diameter is larger than the first internal diameter.

70. The method of claim 69, wherein the second evaporator coils are longer than the first evaporator coils.

71. The method of claim 54, wherein the first evaporator comprises first evaporator coils and the second evaporator comprises second evaporator coils; wherein the second evaporator coils are longer than the first evaporator coils.

72. The method of claim 54, further comprising a second expansion valve located between the first evaporator and second evaporator.

Description:

TECHNICAL FIELD

This invention relates generally to refrigerators, including refrigerators with separate temperature zones controlled by separate heat exchangers.

BACKGROUND

Many modern refrigerators operate by sharing air flow from a single heat exchanger between a freezer compartment and a fresh food compartment to maintain each compartment at desired temperatures. In such refrigerators, colder air typically is borrowed or forced from the freezer compartment to mix with warmer air in the fresh food compartment. This colder air can be forced into the entire fresh food compartment for expedited cooling thereof, or, can be directed to certain areas of the fresh food compartment to chill certain areas more quickly. Generally, the refrigerator and freezer compartments are separated by an insulated wall, with the two compartments not being in thermal communication with each other.

Some conventional refrigerators create dual temperature zones by utilizing adjustable dampers between the two compartments and a thermostat that controls the temperature required to switch off the compressor and evaporator fan. Other refrigerators employ a separate thermostat to electronically control dampers within the freezer compartment. In these refrigerators, temperature settings typically are adjusted in one compartment relative to the other compartment.

SUMMARY

The refrigerator, as detailed herein, provides one or more temperature zones, a system for maintaining the different zones at different temperatures, a first evaporator or heat exchanger for cooling the first zone, a second evaporator or heat exchanger for cooling a separate second zone, and a system for controlling drawer temperatures within the first zone.

In accordance with one embodiment, a refrigerator is provided having a cabinet with a refrigerated compartment. The refrigerated compartment comprises one or more zones in thermal communication with each other and with each zone operated at a particular temperature. In another aspect, a method for controlling the temperatures of one or more zones in a refrigerator is provided.

A refrigerator as detailed herein, comprises one or more temperature zones and a system for controlling the zones at different temperatures. For a more complete understanding of the present invention, reference should be made to the following detailed description and accompanying drawings, wherein like reference numerals designate corresponding parts throughout the figures. Although the figures illustrate a refrigerator having two separate zones, the refrigerator may comprise several zones, which can be maintained at various temperatures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a refrigerator with dual evaporators and a dual air circulation system.

FIG. 2 provides a partial view of a refrigerator with first and second zones, with the first zone being in a drawer.

FIG. 3 provides a partial view of a refrigerator illustrating the air ducts in the first zone.

FIG. 4 provides a partial view of a refrigerator illustrating first zone air inlets and outlets.

FIG. 5 provides a partial view of a refrigerator illustrating the first zone evaporator.

FIG. 6 provides a partial view of a refrigerator illustrating air flow within the first zone.

DETAILED DESCRIPTION

Referring to FIG. 1, a refrigerator 5 includes a refrigeration system for cooling a first zone 10, and a separate, second zone 100. The second zone 100 can be, for example, a fresh food compartment, and the first zone 10 can be, for example, a chilled compartment or drawers (e.g., useful for storing meat). The refrigeration system comprises a compressor 280, a condenser 290, an expansion valve 300, a first evaporator or heat exchanger 20 situated in air flow communication with the first zone 10, and a second evaporator or heat exchanger 110 situated in air flow communication with the second zone 100. The refrigeration system optionally can include a thermostat (not shown). The condenser typically includes a warm air exhaust fan to remove heat from the condenser. The first evaporator 20 substantially cools the first zone 10, while the second evaporator 110 substantially cools the second zone 100. Typically, though not necessarily, the first zone 10 is maintained about 2 to about 10° F. cooler than the second zone 100.

The first zone 10 is cooled by the circulation of air that has been passed over the first evaporator or heat exchanger 20. A first evaporator fan 30 draws air across the first evaporator 20, with the cooled air passing through a first duct 40. The first evaporator fan 30 generates a first air flow 80 within the first zone 10. Although the first duct 40 and first evaporator 20 are located behind the first zone rear wall 50 in FIG. 1, any number of duct configurations are possible for cooling the first zone 10. For example, the first air flow 80 can pass through one or more ducts with one or more inlets and outlets located in various positions throughout the first zone 10. As illustrated in FIG. 1, the first duct 40 is in communication with the first zone 10 by a first zone inlet 60 and a first zone outlet 70. The first zone inlet 60 can be positioned below the first zone outlet 70, above the first zone outlet 70, or horizontal to the first zone outlet 70.

As provided in FIG. 1, the second zone 100 is cooled in manner analogous to first zone 10 by circulation of refrigerated air, which has been passed over the second evaporator or heat exchanger 110. A second evaporator fan 120 draws air across the second evaporator 110, typically with the cooled air passing through a second duct 130 behind the rear wall 170 of the fresh food compartment or second zone 100. The second evaporator fan 120 generates a second air flow 200 within the second zone 100. As illustrated in FIG. 1, second duct 130 is in communication with the second zone 100 by one or more second zone inlets 180 and one or more second zone outlets 190, which can be located in any position with respect to each other. For example, the second zone inlet 180 can be positioned below the second zone outlet 190 or positioned horizontally relative to the second zone outlet 190. Typically, the second zone inlet 180, which admits cooled air into the second zone 100 after contact with the second evaporator 110, is located above the second zone air outlets 190 to assist in the circulation of more dense, colder air.

Although the first zone 10 is situated generally below the second zone 100, near the bottom of the refrigerator in FIGS. 1-5, other arrangements are encompassed by this invention. For example, the first zone 10 can be located above the second zone 100, between the top and bottom of the second zone 100, beside the second zone 100, or otherwise situated anywhere within the second zone 100. Typically, though not necessarily, the first zone 10 is smaller than the second zone 100 and operates at a lower temperature than the second zone 100.

The elements of the refrigeration system are connected in series in a closed loop in a refrigerant flow relationship. In one aspect, the refrigerant flows in a continuous cycle through the expansion valve 300, through the first evaporator 20, through the second evaporator 110, through the compressor 280, through the condenser 290, and returns to the expansion valve 300. In this configuration, air in the first zone 10 passes over the first evaporator 20 and reduces the refrigerant cooling capacity before the refrigerant passes through the second evaporator 110. Accordingly, the first zone 10 is maintained at a lower temperature than the second zone 100, as the refrigerant continuously flows through the refrigeration system.

Although one type of evaporator is shown in the Figures provided herewith, this invention is not limited to a particular type of evaporator or heat exchanger. Rather, the present invention encompasses any type of evaporator or heat exchanger known in the art. For example, an evaporator with tubes or coils in any configuration, and an evaporator with fins, plates, or similar devices attached thereto for improved heat exchange performance, and similar devices, are all encompassed by this invention. In addition, this invention also encompasses any type of compressor, condenser, and expansion device known in the art.

The volume of the first evaporator 20 can be smaller than the volume of the second evaporator 110. The internal volume of the first evaporator 20 can be decreased in several ways, for example, by decreasing the internal diameter of the evaporator coils, shortening the evaporator coils, decreasing the number of evaporator coils, or any combination thereof. Similarly, the internal volume of the second evaporator 110 can be increased in several ways, for example, by increasing the internal diameter of the evaporator coils, lengthening the evaporator coils, increasing the number of evaporator coils, or any combination thereof. For example, the first evaporator 20 can comprise coils with a smaller internal diameter than the internal diameter of the coils of the second evaporator 110. Further, the coils of the first evaporator 20 can have an internal diameter that is about 10% to about 100% of the internal diameter of the coils of the second evaporator 110. For example, the second evaporator 110 can comprise coils with an internal diameter of about ⅜ inch, while the first evaporator 20 can comprise coils with an internal diameter of about 3/16 inch. Here, the refrigerant would expand as it proceeded from the first evaporator 20 to the second evaporator 110. Alternatively, the first and second evaporators can be separated by a second expansion valve through which the refrigerant further expands as it enters the first evaporator 20.

In FIG. 1, the first zone 10 is located below the second zone 100 and a thermally conductive wall 90 separates the two zones. The wall 90 can be formed from any material that allows the first zone 10 to be in thermal communication with the second zone 100. The wall 90 maintains the first air flow 80 substantially independent from the second air flow 200. In one aspect, the wall 90 is formed from metal, plastic, or glass. Typically, the wall 90 is not insulated, but could be insulated to reduce the thermal communication between the first and second zones. In other arrangements, the second zone 100 could share more than one thermally conductive common wall 90 with the first zone 10.

If desired, small gaps can be included between the rear or side walls of the refrigerator 5 and the thermally conductive wall 90 to allow air from the first and second zones to mix to a limited extent. Further, when the first zone 10 comprises one or more compartments or drawers, the first air flow 80 and the second air flow 200 generally mix during the time that the user opens the compartments or drawers. Generally, the first air flow 80 remains substantially independent from the second air flow 200. Alternatively, the thermally conductive wall 90 can be sealed to maintain the first air flow 80 independent from the second air flow 200 when the compartments or drawers in the first zone 10 are closed.

Referring now to FIG. 2, a front sectional view of a refrigerator 5 is shown with both the first and second evaporators or heat exchangers concealed. The evaporators or heat exchangers can be located in any position in the respective zone, as long as the first evaporator is in air flow communication with the first zone 10 and the second evaporator in air flow communication with the second zone 100. The first evaporator can be located, for example, behind the second zone rear wall 170, or optionally, behind the first zone rear wall (not shown). The first evaporator is in air flow communication with the first zone 10 by one or more first zone outlets (not shown) and one or more first zone inlets (not shown). The first zone inlets and outlets can be located in any position relative to each other for effective cooling of the first zone 10. The second evaporator can also be located behind the second zone rear wall 170. The second evaporator is in air flow communication with the second zone 100 by one or more second zone outlets 190 and one or more second zone inlets (not shown). The second zone inlets and outlets can be located in any position relative to each other for effective cooling of the second zone 100. In FIG. 2, the first zone 10 is located below the second zone 100 and the two zones are separated by a thermally conductive wall 90.

As shown in FIG. 2, the first zone 10 can comprise a drawer 210 that abuts or is otherwise proximate the thermally conductive wall 90. Although only one drawer is shown in FIG. 2, the first zone 10 can comprise multiple drawers or compartments. The first zone 10 further comprises one or more ducts for channeling air flow within the first zone 10. For example, the first zone 10 can comprise a left duct 140, a center duct 150, and a right duct 160, any combination of which can be used to circulate air through the first zone 10. The air handling functions are separated into one or more ducts, which can function as air receiving ducts and air distributing ducts. Any of the ducts can encompass or otherwise house or conceal the first evaporator (not shown). The one or more ducts can comprise one or more inlets and outlets (not shown) for air flow communication with the first zone 10. Further, the one or more ducts can include ribs (not shown) for channeling the air in a particular desired direction, depending on the duct and evaporator arrangement.

The drawer 210 optionally has one or more openings (not shown) that correspond to inlets or outlets (not shown) in the receiving ducts or distributing ducts, for allowing air to circulate through the drawer 210. The first zone 10 further can comprise a dial 220 or other operating means to enable a user to open or close the openings in the drawer 210. The dial 220 can also be used in conjunction with blocking features to reduce the size of the openings in the drawer 210. When the openings are closed, air circulates around the drawer 210, but generally not over the thermally conductive wall 90. When the dial is operated to open the openings in the drawer 210, the second zone air circulates through the drawer, directly using the air flow to cool the contents of the drawer. Thus, the user can choose between two modes of operation for cooling the first zone 10. In either mode of operation, the second air flow is maintained substantially independent from the first air flow by the thermally conductive wall 90.

FIG. 3 is a front sectional view of the refrigerator 5 illustrated in FIG. 2 with the thermally conductive wall 90 and drawer 210 removed. Removal of the drawer 210 and wall 90 reveals the left duct 140, right duct 160, first zone rear wall 50, and drawer supports 240. As shown in FIG. 3, the left duct 140, center duct 150, and right duct 160 are not concealed behind the refrigerator walls. However, the ducts optionally can be located behind any refrigerator wall, such as the first zone rear wall 50 or the second zone rear wall 170, in front of the refrigerator walls, or any combination thereof. Additionally, any number of ducts can be included in the first zone 10 and can be arranged in any fashion.

In one aspect, the thermally conductive wall 90 rests on ledge 230, the left duct 140, and the right duct 160. However, the wall 90 can be positioned in the refrigerator in any conventional manner. As illustrated in FIG. 3, the ledge 230 is part of the center duct 150 with the thermally conductive wall 90 abutting the center duct 150 instead of the second zone rear wall 170. The center duct 150 and ledge 230 allow air flow from the first zone 10 into the center duct 150 through the one or more duct apertures 250 in the center duct 150 and ledge 230. In FIG. 3, portions of the center duct 150 are removed to reveal the first evaporator fan 30. The first evaporator fan 30 draws air from the first zone 10 through duct aperture 250 and over the first evaporator 20 (see FIG. 4). Although the first evaporator fan is shown in the center duct in FIG. 3, the first evaporator fan can be located in any of the ducts for generation of air flow in the first zone.

Referring now to FIG. 4, the refrigerator 5 from FIG. 3 is illustrated with the left duct 140, center duct 150, right duct 160, drawer supports 240, and ledge 230 removed. Removal of the center duct 150 exposes the first zone outlet 70 and the first evaporator outlet 260. Portions of the first evaporator 20 are visible through the first zone outlet 70 and the first evaporator outlet 260. The first evaporator 20 is encompassed by a first evaporator duct 270, all of which are located behind the second zone rear wall 170. The first evaporator 20 can be located in any position in the refrigerator with corresponding ducts as long as air flow communication with the first evaporator 20 is maintained.

The first evaporator fan draws air through duct aperture 250 and into the first evaporator duct 270 through the first zone outlet 70. The air reenters the center duct 150 via the first evaporator outlet 260, then enters the first zone 10 through any number of distributing ducts in air flow communication with the center duct 150 and the first zone 10.

In FIG. 5, portions of the second zone rear wall 170 are removed to reveal the first evaporator 20 as encompassed by the first evaporator duct 270. The first evaporator duct 270 optionally can include means for channeling the air in a desired direction over the first evaporator 20. For example, a blocking means (not shown) can be installed and can extend upwardly from the bottom of the first evaporator duct 270 to create a substantially U-shaped air flow channel in the first evaporator duct 270. Thus, air enters the first evaporator duct 270 via the first zone outlet 70, flows through the U-shaped channel over the first evaporator or heat exchanger 20, and exits the first evaporator duct 270 via the first evaporator outlet 260.

In the configuration of FIG. 6, first air flow 80 passes through the center duct 150 and right duct 160. The right duct 160 is in air flow communication with the first zone 10 via the first zone inlet 60. In one aspect, the first zone inlet 60 is located near the front of the right duct 160 away from the first zone rear wall 50. Such a configuration directs air from the front right corner of the first zone 10 to the rear left corner of the first zone 10.

The first zone typically operates at a temperature from about 4° F. to about 7° F. below the average second zone temperature. To achieve this temperature difference, the second evaporator or heat exchanger typically operates at a temperature from about 15° F. to about 20° F., which can create a second zone temperature from about 38° F. to about 43° F. The first evaporator or heat exchanger typically operates at a temperature from about −5° F. to about −10° F., which can create a first zone temperature from about 31° F. to about 34° F.

Both the first and the second evaporator coils are cooled by liquid refrigerant ejected from the high pressure side of a compressor, into the corresponding low pressure evaporator coils. The condenser and condenser fans can be located in a variety of places, for example, under the compartment or on the back of the compartment, for removal of the transferred heat by exhaust or condenser fans.

With respect to the above description, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art. All equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. Further, the various components of the embodiments of the present invention can be interchanged to produce further embodiments and these further embodiments are intended to be encompassed by the present invention. Various modifications can be made to the invention without departing from the scope thereof. Therefore, the foregoing is considered as illustrative only.