COLD STORAGE DEVICE

Abstract

An ice-lined cold storage device (10) comprising: a cold storage compartment (15) arranged at an interior of the ice-lined cold storage device; an ice-lining (25a, 25b, 25c, 25d) configured to absorb heat from the interior of the cold-storage device; a cooling circuit (16) configured, when in operation, to remove heat from the ice-lining; an inner liner (22) arranged between the cold storage compartment and the ice-lining, the inner liner comprising a sheet material (23) having a major surface which faces towards the cold storage compartment and a major surface (27) which faces towards the ice-lining; is provided with an electrical heating element (26) arranged at one of the said major surfaces of the inner to provide heat to the interior of the cold storage device.

Claims

1.-14. (canceled)

15. An ice-lined cold storage device comprising: a cold storage compartment arranged at an interior of the ice-lined cold storage device; an ice-lining configured to absorb heat from the interior of the cold-storage device; a cooling circuit configured, when in operation, to remove heat from the ice-lining; an inner liner arranged between the cold storage compartment and the ice-lining, the inner liner comprising: i) a heat conducting sheet having a first major surface which faces towards the cold storage compartment and a second major surface which faces towards the ice-lining; and ii) a thermally insulating material which separates the cold storage compartment from the ice-lining and which is arranged between the heat conducting sheet and the ice-lining; and an electrical heating element which is arranged between the heat conducting sheet of the inner liner and the thermal insulating material of the inner liner at the second major surface of the heat conducting sheet of the inner liner which faces towards the ice-lining.

16. The ice-lined cold storage device of claim 15, wherein the heat conducting sheet of the inner liner comprises a metal sheet, and the thermally insulating material of the inner liner comprises a sheet of insulating foam.

17. The ice-lined cold storage device of claim 15, wherein the inner liner circumscribes the cold storage compartment and defines a continuous perimeter of the cold storage compartment.

18. The ice-lined cold storage device of claim 17, wherein the electrical heating element extends around at least 70% of a perimeter of the inner liner.

19. The ice-lined cold storage device of claim 15, wherein the electrical heating element is arranged at a position within the cold storage device which is between i) a horizontal plane which intersects a height corresponding to 25% of the height of the cold storage compartment from its base, and ii) a horizontal plane which intersects a height corresponding to 75% of the height of the cold storage compartment from its base.

20. The ice-lined cold storage device of claim 15, further comprising i) a temperature sensor configured to provide an indication of a temperature of the cold storage compartment, and ii) a control system which controls operation of the electrical heating element on the basis of the indication of a temperature of the cold storage compartment provided by the temperature sensor.

21. The ice-lined cold storage device of claim 20, wherein the temperature sensor is arranged in contact with the first major surface of the inner liner.

22. The ice-lined cold storage device of claim 15, wherein the ice-lined storage device is configured to operate with its cold storage compartment having a temperature which is maintained between +2° C. and +8° C.

23. The ice-lined cold storage device of claim 15, wherein the ice lining extends around at least 50% of the periphery of the cold storage compartment.

24. The ice-lined cold storage device of claim 15, wherein the electrical heating element is an electrical heating wire.

25. An ice-lined cold storage device comprising: a cold storage compartment arranged at an interior of the ice-lined cold storage device; an ice-lining configured to absorb heat from the interior of the cold-storage device; a cooling circuit configured, when in operation, to remove heat from the ice-lining; an inner liner arranged between the cold storage compartment and the ice-lining, in which the inner liner circumscribes the cold storage compartment and defines a substantially continuous perimeter of the cold storage compartment, and in which the inner liner comprises a sheet material having a first major surface which faces towards the cold storage compartment and a second major surface which faces towards the ice-lining; and an electrical heater configured to provide heat to the interior of the cold storage device, the electrical heater comprising an electrical heating element arranged at one of the said major surfaces of the inner liner.

26. The ice-lined cold storage device of claim 25, wherein the inner liner comprises a heat conducting metal sheet having a first major surface which faces towards the cold storage compartment and a second major surface which faces towards the ice-lining; and in which the electrical heating element contacts the second major surface of the heat conducting metal sheet.

27. The ice-lined cold storage device of claim 26, wherein the inner liner further comprises a thermally insulating foam material which separates the cold storage compartment from the ice-lining.

28. The ice-lined cold storage device of claim 25, wherein the inner liner comprises a heat conducting metal sheet having a first major surface which faces towards the cold storage compartment and a second major surface which faces towards the ice-lining; and a thermally insulating material which separates the cold storage compartment from the ice-lining and which is arranged between the heat conducting sheet and the ice-lining; and in which the electrical heating element is arranged between the heat conducting sheet of the inner liner and the thermal insulating material of the inner liner.

29. The ice-lined cold storage device of claim 25, wherein the electrical heating element extends around at least 70% of a perimeter of the inner liner.

30. The ice-lined cold storage device of claim 25, wherein the electrical heating element is arranged at a position within the cold storage device which is between i) a horizontal plane which intersects a height corresponding to 25% of the height of the cold storage compartment from its base, and ii) a horizontal plane which intersects a height corresponding to 75% of the height of the cold storage compartment from its base.

31. The ice-lined cold storage device of claim 25, further comprising i) a temperature sensor configured to provides an indication of a temperature of the cold storage compartment, and ii) a control system which controls operation of the electrical heating element on the basis of the indication of a temperature of the cold storage compartment provided by the temperature sensor.

32. The ice-lined cold storage device of claim 31, wherein the temperature sensor is arranged in contact with the first major surface of the inner liner.

33. The ice-lined cold storage device of claim 25, wherein the ice-lined storage device is configured to operate with its cold storage compartment having a temperature which is maintained between +2° C. and +8° C.

34. The ice-lined cold storage device of claim 25, wherein the ice lining extends around at least 50% of the periphery of the cold storage compartment.

35. The ice-lined cold storage device of claim 25, wherein the electrical heating element is an electrical heating wire.

36. A solar powered ice-lined cold storage device comprising: a cold storage compartment arranged at an interior of the ice-lined cold storage device; an ice-lining which extends around at least 50% of a periphery of the cold storage compartment and which is configured to absorb heat from the interior of the cold storage device; a cooling circuit configured, when in operation, to remove heat from the ice-lining; an inner liner which circumscribes the cold storage compartment and defines a substantially continuous perimeter of the cold storage compartment, the inner liner being arranged between the cold storage compartment and the ice-lining, and the inner liner comprising i) a heat conducting metal sheet having a first major surface which faces towards the cold storage compartment and a second major surface which faces towards the ice-lining; and ii) a thermally insulting foam material which separates the cold storage compartment from the ice-lining and which is arranged between the heat conducting metal sheet and the ice-lining; and an electrical heating element provided by an electrical heating wire which extends around at least 70% of a perimeter of the inner liner and which is arranged at the second major surface of the heat conducting metal sheet of the inner liner between the heat conducting metal sheet of the inner liner and the thermal insulating foam material of the inner liner; and wherein the ice-lined storage device is configured to operate with its cold storage compartment having a temperature which is maintained between +2° C. and +8° C.

37. The ice-lined cold storage device of claim 36, further comprising i) a temperature sensor arranged in contact with the first major surface of the heat conductive metal sheet of the inner liner, the temperature sensor being configured to provide an indication of a temperature of the cold storage compartment, and ii) a control system which controls operation of the electrical heating element on the basis of the indication of a temperature of the cold storage compartment provided by the temperature sensor.

Description

[0049] An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0050] FIG. 1 is a schematic perspective view of an ice-lined cold storage device;

[0051] FIG. 2 is a schematic top view (without the lid) of the ice-lined cold storage device;

[0052] FIG. 3 is a schematic view showing an electrically powered cooling circuit of the ice-lined cold storage device; and

[0053] FIG. 4 is a schematic exploded perspective view of an inner liner and electrical heater.

[0054] The ice-lined vaccine refrigerator 10 comprises an insulated, moulded body 11 having an insulated pivoted lid 12. A cooling space 13 within the body 11 is accessible when the lid 12 is open and sealable by closing of the lid 12. Electrical components and control circuitry of the refrigerator 10 are arranged within a component housing 14 which is incorporated into the mounded body 11.

[0055] In particular, the ice-lined vaccine refrigerator 10 comprises: [0056] a vaccine storage compartment 15 within the cooling space 13; [0057] an electrically powered cooling circuit 16, [0058] a power inlet 17 adapted for connection to an external supply of DC power provided from solar panels or from an AC-DC power converter; and [0059] a compressor 18 forming part of the electrically powered cooling circuit 16 of the vaccine refrigerator 10.

[0060] The electrically powered cooling circuit 16 comprises: four flat plate evaporators 19a,19b, 19c, 19d, each arranged at a peripheral side wall of the cooling io space 13, the evaporators being fed with refrigerant which is circulated by the compressor 18 through a condenser 20, subsequently through a capillary tube or expansion valve 21 and subsequently through the evaporators before returning to the compressor 18.

[0061] An inner liner 22 is arranged within the cooling space 13, the internal periphery of the inner liner 22 defining the peripheral side walls of cold storage compartment 15. The inner liner 22 comprises a substantially continuous metal sheet 23, notably an aluminium sheet, having a thickness of 1-2 mm, and a substantially continuous layer of insulation 24, notably sheets of expanded polypropylene or expanded polystyrene having a thickness of about 8 mm which are adhered to and cover each major surface of the metal sheet which faces an evaporator plate 19a, 19b, 19c, 19d. This is an example of a preferred configuration in which the inner liner provides a substantially continuous sleeve or barrier which separates the cold storage compartment 15 from the ice lining.

[0062] A removeable ice pack 25a, 25b, 25c, 25d is arranged in each of the spaces between the evaporator plates 19a,19b, 19c, 19d and the inner liner 22. The ice packs 25a, 25b, 25c, 25d thus form an ice lining which in this case provides an ice lining at each of four sides of a substantially rectangular vaccine storage compartment 15. In operation, the electrically powered cooling circuit 16 freezes the icepacks 25a, 25b, 25c, 25d which generates an ice lining and cools the vaccine storage compartment 15. As illustrated in FIG. 2, the ice lining does not extent around corner sections of the cold storage compartment 15 but nevertheless extends around the majority and in the illustrated case at least 80% of the periphery of the cold storage compartment 15. Arrangement of the thermally insulated inner liner 22 between the ice packs 25a, 25b, 25c, 25d and the vaccine storage compartment 15 reduces the risk of undesirably cooling the vaccine storage compartment 15 to a temperature of below +2° C.

[0063] FIG. 4 illustrates an electrical heating element in the form of a single electrical heating wire 26 which is adhered to a major surface of the inner liner 22, in this case the major surface 27 of the metal sheet 23 which faces the ice lining 25a, 25b, 25c, 25d. The electrical heating wire 26 is thus positioned between the metal sheet 23 and the insulating sheet 24 of the inner liner 22 and passes around the entire periphery of n the inner liner 22 and of the cold storage compartment at a height 28 which corresponds to a horizontal plane which intersects a height corresponding to 50% of the height of the inner liner 22 from its base and which also corresponds in the illustrated example to 50% of the height of the cold storage compartment 15 from its base. The electrical wire heating element 26 comprises a wire loop within an electrically insulated sleeve with each of the two ends of the loop arranged at an electrical heating wire connector 29. A temperature sensor 30 contacts a major surface of metal sheet 23 of the inner liner 22, in the illustrated case the major surface of the inner liner 22 which is in direct contact with the air in the cold storage compartment 15, to provide an indication of the temperature of the cold storage compartment 15. The height position of the temperature sensor is preferably offset from the height position of the electrical heating wire to mitigate against direct heat transfer creating an erroneous temperature reading.

LIST OF REFERENCE NUMBERS

[0064] 10 ice-lined vaccine refrigerator [0065] 11 moulded body [0066] 12 lid [0067] 13 cooling space [0068] 14 component housing [0069] 15 vaccine storage compartment [0070] 16 electrically powered cooling circuit [0071] 17 power inlet [0072] 18 compressor [0073] 19a evaporator [0074] 19b evaporator [0075] 19c evaporator [0076] 19d evaporator [0077] 20 condenser [0078] 21 expansion valve [0079] 22 inner liner [0080] 23 metal sheet of inner liner [0081] 24 insulation sheet of inner liner [0082] 25a ice pack [0083] 25b ice pack [0084] 25c ice pack [0085] 25d ice pack [0086] 26 electrical heating wire [0087] 27 major surface of metal sheet of inner liner [0088] 28 height of electrical heating wire [0089] 29 electrical heating wire connector [0090] 30 temperature sensor