Display cabinets for frozen products

Abstract

Display cabinet for frozen products including a magneto caloric unit having cold end with a primary cold heat exchanger and a hot end with a primary hot heat exchanger, and a cabinet suitable for containing frozen products. The cabinet including an inner wall limiting a volume wherein frozen products can be stored, the cabinet having a secondary heat exchanger, wherein the secondary cold heat exchanger includes an exchanger circulator for circulating a low freezing point liquid between the secondary cold heat exchanger and the primary cold heat exchanger.

Claims

1. A display cabinet for frozen products comprising: a Magneto Caloric unit having cold end with a primary cold heat exchanger and a hot end with a primary hot heat exchanger; and a cabinet suitable for containing frozen products, the cabinet comprising an inner wall limiting a volume configured for the storage of frozen products, the cabinet having a secondary cold heat exchanger, wherein the secondary cold heat exchanger comprises an exchanger circulator configured for circulating a low freezing point liquid between the secondary cold heat exchanger and the primary cold heat exchanger; wherein the secondary cold heat exchanger has a wall circulator for circulating the low freezing point liquid close to the inner wall of the cabinet, the wall circulator having at least one inlet and at least one outlet, the inlet being in a top half of the wall, the outlet being in a bottom half of the wall; wherein the inlet opens into a manifold from which a multiplicity of flow passages extend; and wherein the low freezing point liquid is isolated from the primary hot heat exchanger.

2. The display cabinet according to claim 1, wherein the low freezing point liquid has a freezing point of between −30° C. and −40° C.

3. The display cabinet according to claim 1, wherein, in operation, a temperature of the low freezing point liquid in the secondary cold heat exchanger remains below −18° C. and rise between 2° C. and 5° C.

4. The display cabinet according to claim 1, wherein the cabinet is an open top display cabinet.

5. The display cabinet according to claim 1, wherein the wall circulator and the inner wall are roll bonded.

6. The display cabinet according to claim 1, wherein the manifold is dimensioned and positioned such that substantially identical pressure drops are achieved in all the different flow passages.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention will be further described by reference to the following figures wherein:

(2) FIG. 1 represents a schematic view of a display cabinet according to the invention,

(3) FIG. 2 represents a schematic view of a secondary cold exchanger according to the invention,

(4) FIG. 3 represents a schematic view of another secondary cold exchanger according to the invention.

(5) As represented in FIG. 1, a display cabinet according to the invention comprises a Magneto Caloric Unit 1 with a cold end 11 and a hot end 12. The display cabinet also has a inner wall 2 limiting a volume 3 wherein frozen products can be stored, said cabinet having a secondary cold heat exchanger 4, wherein the secondary cold heat exchanger 4 comprises circulating means 5 for circulating a low freezing point liquid between said secondary cold heat exchanger 4 and a primary cold heat exchanger 6 located at the cold end 11 of the MCU 1.

(6) When in operation, the cold end 11 of the MCU 1 is at a temperature of −23° C., the hot end 12 being at a temperature of 30° C.

(7) As represented in FIG. 2, a display cabinet with a volume 3 limited by four vertical walls 21, 22, 23 and 24 has a secondary cold heat exchanger in the form of a coil 41 going from the top of a wall (21, 22, 23 or 24) to the bottom of a wall (21, 22, 23, or 24), the inlet being at the top and the outlet being at the bottom. The low freezing point liquid is Clogel 2503, a formulation based on nontoxic mono propylene, non flammable and unexploded.

(8) (http://www.chimiphar.fr/index.php?option=com_content&task=view&id=16&Itemid=34)

(9) At hot end 12, circulating means 120 allow for the circulation of a heat transfer fluid, which can be simply water, from a primary hot heat exchanger 7 to a secondary hot heat exchanger 121.

(10) A display cabinet has described in FIG. 2, submitted to a heat load of 95 W, and through which a the low freezing point liquid flows at 17.5 g/s under a pressure drop of 1.6 bar
had a wall temperature in its volume 3 of between −19° C. at the top and −22° C. at the bottom, the temperature, 5.5 centimeters beneath the glass top, being −16° C., the temperature in the centre of the volume being around −16° C.

(11) As represented in FIG. 3, a display cabinet with a volume 3 limited by four vertical walls 21, 22, 23 and 24 has its secondary cold heat exchanger made of two sub-circuits 42 and 43. The volume 3 being symmetrical w.r.t to a vertical symmetry plane the sub circuit 42 is substantially a mirror image of sub circuit 43 with regard to the symmetry plane. The inlet of each sub circuit (42 or 43) is located in the top half of a wall (21, 22, 23 or 24), the outlet of each sub circuit being located in the bottom half. Each inlet is divided into a multiplicity of passages 44 by a manifold 45. The passages 44 of each sub circuit (42 or 43) connect back at the bottom of the volume 3 through a manifold 46.

(12) A display cabinet as described in FIG. 3 submitted to a heat load of 95 W, and through which a the low freezing point liquid flows at 26 g/s under a pressure drop of 0.07 bar
had a wall temperature in its volume 3 of between −19° C. at the top and −22° C. at the bottom, the temperature, 5.5 centimeters beneath the glass top, being −18° C., the temperature in the centre of the volume being around −18° C.

(13) This shows that an embodiment as described in FIG. 3 achieve a better cooling than an embodiment according to FIG. 2 while consuming less energy (smaller pressure drop).