WO2008150103A2

WO2008150103A2 - Supercooling apparatus

Info

Publication number: WO2008150103A2
Application number: PCT/KR2008/003135
Authority: WO
Inventors: Su-Cheong Kim; Jong-Min Shin; Deok-Hyun Youn; Cheol-Hwan Kim; Won-Young Chung; Hoon-Bong Lee
Original assignee: Lg Electronics, Inc.
Priority date: 2007-06-04
Filing date: 2008-06-04
Publication date: 2008-12-11
Also published as: WO2008150103A3

Abstract

A supercooling apparatus maintains a supercooled state of a stored item stably for an extended period of time by applying energy intensively to a predetermined area. The supercooling apparatus comprises: an electrode unit including a first electrode and a second electrode of different areas arranged to face each other; a storage unit formed between the first electrode and the second electrode; and a chilled air supply block including a chilled air flow path to supply chilled air to the storage unit.

Description

SUPERCOOLING APPARATUS

Technical Field

[1] The present invention relates to a supercooling apparatus capable of stably maintaining a supercooled state of a stored item for an extended period of time by applying energy intensively to a specific area. Background Art

[2] Supercooling is a phenomenon that a liquid is not transited to a solid even below its phase transition temperature but maintained in a high temperature phase, i.e. a liquid phase. For example, water drops are supercooled in natural conditions. Incidentally, water or a beverage does not freeze but may remain in a supercooled state even in a freezer compartment of the ordinary refrigerator. A freezing method disclosed under Japan Laid-Open Patent Official Gazette S59-151834 and a freezing method and a refrigerator disclosed under Japan Laid-Open Patent Official Gazette 2001-086967 incorporate supercooling principles into the refrigerator. Both provide a technique for keeping foods in a supercooled state below the phase transition temperature by applying an electric field or a magnetic field to the foods in the refrigerator. Moreover, an electrostatic field treatment method disclosed under International Publication Official Gazette WO/98/41115 suggests diverse types of electrode structures that are suitable for freezing and thawing foods.

[3] FIG. 1 shows one example of a refrigerator with a special refrigeration container as disclosed in Korean Patent Application Publication No. 2003-0038999. A refrigerator body 10 includes a freezer compartment 20, a refrigerator compartment 30, a special refrigeration container 41 located at the bottom of the refrigerator compartment 30, and freezer and refrigerator doors 21 and 31 hinged to the body 10 to access the freezer compartment 20 and the refrigerator compartment 30, respectively.

[4] The special refrigeration container 41 is a space for keeping perishable foods such as fish, meat, etc. This special room comes in handy especially when one does not want to spend so much additional time for thawing frozen fish, meat or poultry having been kept in the freezer compartment 20.

[5] Nevertheless, the special refrigeration container having a lower temperature than the refrigeration chamber in a conventional refrigerator is not yet suitable to keep seafood or meat for a long period of time because it is not chiller than the freezer compartment. Therefore, a user still has to put fish or meat into the freezer compartment if she wants to preserve it longer than several tens of hours, and this leaves the inconvenience of thawing unsolved. In other words, a stored item such as water may remain in a su- percooled state for a short period of time, but there should be a way to preserve moisture-containing food products in a supercooled state for an extended period of time as well because freezing moistures in the food products is not always ideal from the perspective of food quality and extension of storage period.

Disclosure of Invention

Technical Problem [6] An object of the present invention is to solve the aforementioned problems in the prior art. An object of the present invention is to provide a supercooling apparatus with a non-freezing chamber to preserve food at a phase transition temperature of liquid or below for a long period of time, without freezing the food. [7] Another object of the present invention is to provide a supercooling apparatus capable of maintaining a stable supercooled state of a stored item at a lowest possible temperature. [8] A further object of the present invention is to provide a supercooling apparatus having electrodes to apply an electric field intensively to a target food product in a specific area, so that the food product can be preserved in a supercooled state more stably for a long period of time. [9] Still further object of the present invention is to provide a supercooling apparatus capable of preventing the release of a non-frozen state of a food product which takes place when heat is generated by electrodes generating an electric field. [10] Yet further object of the present invention is to provide a supercooling apparatus having insulated electrodes, so that a current may not be impressed to a food product or a user may be protected from the exposure to an electric shock.

Technical Solution [11] According to an aspect of the present invention, there is provided a supercooling apparatus, including: an electrode unit including a first electrode and a second electrode of different areas arranged to face each other; a storage unit formed between the first electrode and the second electrode; and a chilled air supply block including a chilled air flow path to supply chilled air to the storage unit. [12] In an exemplary embodiment, the first electrode is a hollow-type electrode, and the chilled air flow path includes a hollow formed at the first electrode. [13] In an exemplary embodiment, the second electrode surrounds the first electrode and the storage unit is formed in a space between the first electrode and the second electrode surrounding the same. [14] In an exemplary embodiment, the first electrode is an active electrode and the second electrode is a ground electrode. Also, the first electrode has a broader area than the second electrode, and the ground electrode is formed facing the center of the active electrode. [15] In an exemplary embodiment, the active electrode surrounds the ground electrode to form the storage unit. [16] Another aspect of the present invention provides a supercooling apparatus, including: a first hollow electrode; a second hollow electrode disposed outside the first electrode, surrounding the same; a non-freezing chamber formed between the first electrode and the second electrode; and a chilled air flow path for guiding chilled air into a storage space through a hollow of the first electrode. [17] Preferably, the supercooling apparatus further includes a power supply for applying a high voltage to the first electrode and/or the second electrode. [18] Preferably, the supercooling apparatus further includes an insulation film coated over an outer face of the first electrode. [19] Preferably, the supercooling apparatus further includes an insulation film coated over an outer face of the second electrode. [20] In an exemplary embodiment, the chilled air flow path guides chilled air from one end of the first electrode to the other end of the same. [21] In an exemplary embodiment, the chilled air flow path discharges chilled air from the other end of the first electrode into the storage space. [22] In an exemplary embodiment, one of the first and second electrodes is an active electrode and the other is a ground electrode. [23] Still another aspect of the present invention provides a supercooling apparatus, including: a container having a storage space to store an item; a refrigeration cycle for cooling the storage space; and an electrode unit including a first electrode and a second electrode of different areas arranged symmetrically in the storage space, thereby keeping the item in a non-frozen state at a phase transition temperature or below. [24] In an exemplary embodiment, the electrode unit is mounted at an inner lateral side of the container. [25] In an exemplary embodiment, the first electrode is an active electrode and the second electrode is a ground electrode, the first electrode having a broader area than the second electrode. [26] In an exemplary embodiment, the ground electrode is formed facing the center of the active electrode. [27] In an exemplary embodiment, the ground electrode and the active ground are spaced apart by a predetermined gap. [28] Yet another aspect of the present invention provides a supercooling apparatus, including: a storage space for storing an item; a refrigeration cycle for cooling the storage space; and an electrode unit including an active electrode and a ground, counter electrode, for generating an electric field in the storage space, wherein the active electrode surrounds the ground electrode to define the storage space and the item stays in a non-frozen state at a phase transition temperature or below.

[29] In an exemplary embodiment, the active electrode and the ground electrode are spaced apart by a predetermined gap.

[30] In an exemplary embodiment, the active electrode has a cylindrical shape.

Advantageous Effects

[31] A non-freezing chamber in the supercooling apparatus of the present invention makes it possible to preserve food at a liquid-solid phase transition temperature or below for an extended period of time, without freezing the food. [32] The supercooling apparatus of the present invention is suitable for maintaining a stable supercooled state of a stored item at a lowest possible temperature. [33] The supercooling apparatus of the present invention has electrodes to apply an electric field intensively to a target food product in a specific area, so that the food product can be preserved in a supercooled state more stably for a long period of time. [34] Although the electrodes produce heat while generating an electric field, the supercooling apparatus of the present invention has a suitable mechanism to prevent the release of a non-frozen state of a food product. [35] The electrodes used for the supercooling apparatus of the present invention are insulated, so that a current may not be impressed to a food product or a user may be protected from the exposure to an electric shock.

Brief Description of the Drawings [36] FIG. 1 shows one example of a conventional refrigerator with a special refrigeration container; [37] FIG. 2 is a schematic view of an electrode structure in a supercooling apparatus to maintain a supercooled state in general; [38] FIG. 3 is a graph representing a supercooling phenomenon in a supercooling apparatus incorporating the electrode structure of FIG. 2; [39] FIG. 4 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 2; [40] FIG. 5 is a schematic view of an advanced electrode structure in a supercooling apparatus to maintain a supercooled state; [41] FIG. 6 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 5; [42] FIG. 7 is a schematic view of another advanced electrode structure in a supercooling apparatus to maintain a supercooled state; [43] FIG. 8 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 7; [44] FIG. 9 is a schematic view of yet another advanced electrode structure in a supercooling apparatus to maintain a supercooled state;

[45] FIG. 10 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 9;

[46] FIG. 11 shows a non-freezing chamber including a cold air flow path, in accordance with a first embodiment of the present invention;

[47] FIG. 12 shows a non-freezing chamber including a cold air flow path, in accordance with a second embodiment of the present invention; and

[48] FIG. 13 is a block diagram to explain the operating method of a supercooling apparatus.

[49]

Mode for the Invention

[50] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[51]

[52] When liquid such as water is cooled slowly, it does not freeze for some time even though the temperature is below 0⁰C. However, when an object becomes a supercooled state, it is a sort of metastable state where the unstable equilibrium state breaks easily even by a very small stimulus or minor external disturbance, so the object easily transits to a more stable state. That is to say, if a small piece of the material is put into a supercooled liquid, or if the liquid is subject to impact on a sudden, it starts being solidified immediately and temperature of the liquid is raised to a freezing point, maintaining a stable equilibrium state at the temperature.

[53] Even if the temperature is lower than the phase transition temperature at this time, the supercooled state can be maintained continuously as long as molecules are allowed to do at least one of the following: rotation, vibration, and translation constantly. In other words, if energy is supplied at the same time with the liquid cooling process (i.e. offsetting the energy absorbed during the cooling process) and to inhibit phase transition from liquid to solid, the liquid phase can be maintained stably for an extended period of time even at temperature lower than the phase transition temperature. In particular, the energy supply process should not be the same as the energy absorption process because they have influence over each other. In a typical cooling apparatus, the liquid is deprived of heat energy to get frozen, so it is not proper to choose heat energy to be supplied.

[54]

[55] FIG. 2 is a conceptual schematic view showing an electrode structure in a supercooling apparatus to maintain a supercooled state in genera. [56] In FIG. 2, a casing 1 includes two built-in electrodes 10a and 10b on opposite sides of a storage space S 1 defined therein. The casing 1 further includes a power supply 2 to apply a high-voltage AC power to the electrodes 10a and 10b. When a high- voltage AC power is applied to the electrodes 10a and 10b by the power supply 2, an electric field is generated in the storage space Sl between the electrodes 10a and 10b and energy is supplied to the storage space S 1 through the electric field.

[57] The storage space Sl is designed to take energy away from it under the operation of a refrigeration cycle (not shown) and to supply another kind of energy (i.e. electric field energy). In result, items like water or moisture-containing food products in the storage space S 1 can be preserved stably in a refrigerated state, without coagulating or freezing even below the phase transition temperature, for a long period of time.

[58] FIG. 3 is a temperature graph showing a temperature change of water that has been cooled down in the supercooling apparatus incorporating the electrode structure of FIG. 2.

[59] Normally, when water is cooled down below its phase transition temperature, it undergoes liquid-solid phase transitions.

[60] For the observation, 0. l/(liter)of distilled water was put into a storage space S 1 of the casing 1 as shown in FIG. 2, and the electrodes 10a and 10b having a wider surface than the storage space Sl are arranged on opposite sides of the storage space Sl. The gap between the electrodes 10a and 10b is 20mm. The casing 1 is made out of an acrylic material, and slid into and cooled down in a refrigerating space (a refrigerating apparatus having no supplementary electric field generator besides the electrodes 10a and 10b) to which chilled air is uniformly dispersed.

[61] The power supply 2 applies 0.9IkV (6.76mA), 2OkHz AC to the electrodes 10a and

10b, and the inside temperature of a refrigerating space is about -7°C.

[62] As evident in the graph of FIG. 3, a supercooled state (or non-frozen state) can be maintained stably for an extended period of time by supplying energy through an electric field.

[63] FIG. 4 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 2. In particular, the supercooling apparatus of FIG. 4 is an indirect cooling (e.g., fan cooling) type apparatus with a refrigeration cycle.

[64] The supercooling apparatus is constituted of a casing 110 which has one open side and a storage space A being partially divided by a shelf 130, and a door 120 for opening or closing the open side of the casing 110. A refrigeration cycle 30 of the indirect cooling type super cooling apparatus is constituted by a compressor 32 for compressing a refrigerant, an evaporator 33 for producing chilled air (indicated by arrows) to cool the storage space A or a stored item, a fan 34 for forcibly circulating the produced chilled air, an inlet duct 36 for introducing the chilled air into the storage space A, and an outlet duct 38 for leading the chilled air having passed through the storage space A to the evaporator 33. Although not shown, the refrigeration cycle 30 can further include a condenser, a drier, an expansion unit, etc. For the supercooling apparatus, the refrigeration cycle can be embodied based on the direct cooling system as well as the indirect cooling system.

[65] Electrodes 50a and 50b are formed between inner faces 112a and 112c facing the storage space A and the outer faces of the casing 110. The electrodes 50a and 50b are arranged to face the storage space A from opposite sides, so that an electric field can be applied to the entire storage space A. The storage space A is formed between the electrodes 50a and 50b or at the center, being spaced apart from the ends of the electrodes 50a and 50b by a predetermined distance in the inward direction, such that a uniform electric field may be applied to the storage space A or the stored item.

[66] The inlet duct 36 and the outlet duct 38 are formed in the inner face 112b of the casing 110. In addition, surfaces of the inner faces 112a, 112b, and 112c of the casing 110 are made of a hydrophobic material such that the surface tension of water or moisture is reduced and do not freeze during the supercooling mode. Needless to say, the outer faces and the inner faces 112a, 112b, and 112c of the casing 110 are made of an insulating material to protect a user from the exposure to an electric shock generated from the electrodes 50a and 50b and at the same time, to prevent a stored item from coming into a direct electrical contact with the electrodes 50a and 50b via the inner faces 112a, 112b, and 112c. Although the indirect cooling type supercooling apparatus has been illustrated, it is evident that the present invention can be embodied in a direct cooling type supercooling apparatus as well.

[67] In this manner, a uniform electric field may be generated in the storage space through electrodes. However, food products are put into a refrigeration apparatus preserving items in a cooled state at different times, and have different masses. This means that each food is cooled down at a different time point according to its mass, and the refrigeration apparatus may have to supply energy intensively for supercooling at different timings. Under these circumstances, if the refrigeration apparatus can supply energy to the right place at the right time by generating a stronger electric field, a supercooled state might be created more efficiently.

[68] FIG. 5 is a conceptual schematic view of an advanced electrode structure of a supercooling apparatus to maintain a supercooled state. A planar electrode 11a and a cylindrical electrode (e.g., wire) 1 Ib are connected to a power supply. When power (especially, a high- voltage AC power) is fed to the electrodes from the power supply, a stronger electric field is generated around the cylindrical electrode 1 Ib. In terms of lines of electric force, lines are wound more densely around the cylindrical electrode 1 Ib, thereby creating a stronger electric field closer towards the cylindrical electrode (the cylindrical electrode shown in FIG. 5 is provided for illustrative purpose only as the structure for concentrating an electric field to a specific area).

[69] FIG. 6 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 5. Similar to the refrigerator shown in FIG. 3, an indirect cooling type refrigerator of FIG. 6 includes a refrigeration cycle constituted by a shelf 130, a casing 110, a door 120, a compressor 32, an evaporator 33, and a fan 34. However, one of electrodes 50b and 50c is a planar electrode 50b and the other is a cylindrical electrode 50c.

[70] While all the electrodes 50a and 50b in the indirect cooling type refrigerator of FIG.

3 are planar, one 50c out of the electrodes (50c) in the refrigerator of FIG. 6 is cylindrical. Therefore, as discussed earlier, a stronger electric field is created around the cylindrical electrode 50c than in other areas. If a target item to be supercooled is placed over the shelf 130, the item can stay supercooled more stably than others.

[71] FIG. 7 is a conceptual schematic view of another advanced electrode structure of a supercooling apparatus to maintain a supercooled state. A planar electrode l ie and a globular electrode 1 Id are connected to a power supply. When power (especially, a high- voltage AC power) is fed to the electrodes from the power supply, a stronger electric field is generated around the cylindrical electrode 1 Ib. In terms of lines of electric force, lines are wound more densely around the globular electrode 1 Id, thereby creating a stronger electric field closer towards the globular electrode 1 Id. As FIG. 4 adopted the cylindrical electrode 1 Ib, FIG. 7 adopted the globular electrode 1 Id to generate an electric field intensively in a specific area. Overall, these diverse electrode structures make it possible to create a stronger electric field at a desired place, and help a supercooling to perform a supercooling operation at higher efficiency (the cylindrical electrode of FIG. 5 or the globular electrode of FIG. 7 is provided for illustrative purpose only as the structure for concentrating an electric field to a specific area).

[72] FIG. 8 shows one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 7. Similar to the refrigerator shown in FIG. 4, the apparatus of FIG. 8 includes a refrigeration cycle constituted by a shelf 130, a casing 110, a door 120, a compressor 32, an evaporator 33, and a fan 34. However, one of electrodes 50b and 50d is a planar electrode 50b and the other is a cylindrical electrode 50d. While all the electrodes 50a and 50b in the indirect cooling type refrigerator of FIG. 4 are planar, one 50d out of the electrodes in the refrigerator of FIG. 8 is globular. Therefore, as discussed earlier, a stronger electric field is created around the globular electrode 50d than in other areas. If a target item to be supercooled is placed over the globular electrode 50d of the shelf 130, the item can stay supercooled more stably than others.

[73] As can be seen from the embodiment of FIG. 6 or FIG. 8, energy can be supplied intensively to a target item or a target portion to be supercooled by moving the cylindrical electrode or the globular electrode to the target area, making a high efficient use of the supercooling apparatus.

[74] FIG. 9 is a conceptual schematic view of yet another advanced electrode structure of a supercooling apparatus to maintain a supercooled state. A cylindrical electrode (e.g., wire) 13b is surrounded by another electrode 13a. A stronger electric field is generated closer toward the cylindrical electrode 13b (again, the cylindrical electrode is provided for illustrative purpose only as the structure for concentrating an electric field to a specific area). Preferably, the electrode 13a surrounding the cylindrical electrode may be a hollow cylindrical electrode having the center of the cylindrical electrode as a core. Calculation processes to obtain an electric field intensity at each spot through the Maxwell's Equation are well known to those skilled in the art.

[75]

[76] MathFigure 1

[Math.l]

[77] where r is a distance between the center of the cylindrical electrode and a spot of which electric field is to be measured, a is a radius of the cylindrical electrode, and b is a distance between the center of the cylindrical electrode and the electrode surrounding the cylindrical electrode (refer to FIG. 9).

[78] Therefore, the closer towards the cylindrical electrode, that is, the smaller the radius r in Eq. 1 is, the stronger an electric field becomes.

[79] FIG. 10 is one embodiment of the supercooling apparatus incorporating the electrode structure of FIG. 9. The apparatus includes a cylindrical electrode 13c surrounded by another electrode 13d, and a refrigeration cycle constituted by a compressor 32 for compressing a refrigerant, and an evaporator 39 for evaporating the refrigerant. In short, the supercooling apparatus cools down a stored item through the refrigeration cycle, and supplies power to generate energy intensively around the cylindrical electrode 13c.

[80] Meanwhile, when a supercooling apparatus uses electrodes to apply energy intensively to a certain area and to thus maintain a stable supercooled state for an extended period of time, there is one thing to consider. That is, the electrodes produce heat when a current is fed to them. Since the supercooled state can be released by such heat, it is necessary to cool down the electrodes primarily. Hence, one needs to make sure the electrodes, a small surface area of the electrode to be more specific in which current or charges are concentrated, are provided with sufficient chilled air. For this reason, an electrode with a relatively small surface area is formed into a hollow cylindrical shape, and the other electrode with a relatively large surface area is formed into a hollow cylindrical shape to encompass the electrode with a relatively small surface area. Moreover, if chilled air can be exhausted through a hollow of the electrode with a relatively small surface area, it is possible to cool down the electrodes more intensively despite the heat flowing in them.

[81] FIG. 11 shows a non-freezing chamber including a cold air flow path, in accordance with a first embodiment of the present invention.

[82] A non-freezing chamber 200 is located inside a refrigerator compartment (not shown) into which chilled air produced by heat exchange with the refrigeration cycle flows to preserve food products at low temperature. A supercooling apparatus according to a first embodiment of the present invention includes a first electrode 212, a second electrode 214, a cold air flow path 220, and casings 230, 232, and 234. The non- freezing chamber 200 is defined between the first electrode 212 and the second electrode 214, and used to keep foods like meat, fish, etc. Thus, an electric field may be applied intensively to the foods in the non-freezing chamber 200. The first electrode 212 has a hollow bar shape with a circular (e.g., cylindrical or oval) or polygonal shape cross section. The second electrode 214 also has a hollow bar shape with a circular (e.g., cylindrical or oval) or polygonal shape cross section but with a larger diameter than that of the first electrode 212 to be able to encompass it. When a current is applied to the first and second electrodes 212 and 214, an electric field is generated in the space, namely the non-freezing chamber 200, between the first electrode 212 and the second electrode 214.

[83] The first and second electrodes 212 and 214 are connected to a power supply (not shown) supplying a high- voltage AC power to them. When a high-voltage AC power is fed to the first and second electrodes from the power supply (not shown), an electric field is generated in the non-freezing chamber 200 to supply energy to it.

[84] Here, one of the first and second electrodes 212 and 214 is an active electrode, while the other is a ground electrode. That is to say, if the first electrode 212 is an active electrode, the second electrode 214 becomes a ground electrode; if the second electrode 214 is an active electrode, the first electrode 212 becomes a ground electrode. Regardless of the electrode type (active or ground), the first electrode 212 has a smaller area than the second electrode 214, so an electric field is concentrated onto the first electrode 212. Thus, a food product located closer to the first electrode 212 receives an electric field more intensively.

[85] Moreover, the chilled air flow path 220 is formed in a hollow of the first electrode

212. Chilled air flows into the non-freezing chamber 200 from the top of the first electrode 212. Since the electrodes 212 and 214 produce heat when a current is applied to them, the heat is transferred to a food product in contact with the electrodes 212 and 214, releasing a supercooled state. Especially, more heat may be produced by the first electrode 212 where an electric field is concentrated. However, if the chilled air flow path 220 is formed inside the first electrode 212, it is possible to cool down the first electrode 212 before chilled air flows into the non-freezing chamber 220. As such, the food product may stain in a supercooled state, without being affected by heat from the electrodes 212 and 214.

[86] Unfortunately though, since a high-voltage current flows in the first and second electrodes 212 and 214, there is the possibility that a user is exposed to an electric shock when he or she puts a food product into the non-freezing chamber 200 or takes a food product out of the non-freezing chamber 200. Therefore, either the outer face of the first electrode 212 or the inner face of the second electrode 214 should be insulated to prevent it. If both the outer face of the first electrode 212 and the inner face of the second electrode 214 are insulated, the user can use the supercooling apparatus even more safely. Thus, the top and outer faces of the first electrode 212 are coated with an insulation film 212a.

[87] The casing 230 where the first and second electrodes 212 and 214 are fixed is disposed outside the second electrode 214. It is designed to have a shape and size corresponding to the shape and size of the second electrode 214, such that the outer face of the second electrode 214 is closely adhered to the inner face of the casing 230. The casing 230 has an open top with a circular (e.g., cylindrical or oval) or polygonal shape cross section, depending on the shape of the second electrode 214. The first electrode 212 is fixed at the bottom face of the casing 230, and the second electrode 214 is fixed at the bottom and inner faces of the casing 230. Preferably, the casing 230 is made out of an insulating material. The casing 230 can be manufactured as one body with a casing (not shown) that defines a refrigerator compartment, or can be manufactured separately and then connected to the casing that defines a refrigerator compartment.

[88] A chilled air hole 232 is formed at the bottom face of the casing 230 to guide chilled air that flows in the refrigeration compartment into the chilled air flow path 220 prepared in the hollow of the first electrode 212. The chilled air hole 232 overlaps with the chilled air flow path 220 inside the first electrode 212, so that chilled air produced from the heat exchange with a refrigeration cycle (not shown) inflows through the chilled air hole 232.

[89] The supercooling apparatus according to the first embodiment of the present invention further includes a cover 240 to open/close the open top of the casing 230. The cover 240 has the same shape as the top face of the casing 230, and a stepped portion 241 is formed at each upper side edge of the cover 240 to make the cover stably joined to the casing 230. The cover 240 is preferably made out of an insulating material. In so doing, it is possible to prevent an electric field generated by the first and second electrodes 212 and 214 from leaking to another region of the refrigeration compartment or to outside the supercooling apparatus through the cover 240.

[90] The cover 240 further includes a handle 242 to make it easier for the user to open or close the casing 230. The handle 242 in the first embodiment of the present invention is a pair of tilted or curved grooves formed in the casing 230. As another example of the handle 242, a projection protruding from the top of the casing 230 can also be used.

[91] There is a space between the top of the first electrode 212 and the cover 240. Thanks to this space, chilled air having reached the top of the first electrode 212 via the chilled air flow path 220 inside the first electrode 212 is not blocked (by the cover 240), but freely flows into the non-freezing chamber 200.

[92] FIG. 12 shows a non-freezing chamber including a cold air flow path, in accordance with a second embodiment of the present invention.

[93] Similar to the first embodiment of a supercooling apparatus having a chilled air flow path, the second embodiment of a supercooling apparatus having a chilled air flow path includes a first electrode 212, a second electrode 214, a chilled air flow path 220, and casings 230: 232 and 234. It further includes a defrosting device 250, a drainage hole 234, and a food product shelf 260.

[94] The defrosting device 250 is provided between the second electrode 214 and the casing 230. In general, when frost is formed at the electrodes 212 and 214, electric field intensity gets weaker and is not uniform, so foods preserved in the non-freezing chamber 200 may not stay in the non-frozen or supercooled state. However, the defrosting device 250 detects the formation of frost at the electrodes 212 and 214, and starts operating once it detects frost. In this way, the non-freezing chamber 200 maintains its environment more stably. If the defrosting device 250 is available, the drainage hole 234 to drain the defrost water should be provided to the casing 230 as well. This is because if the defrost water remains in the non-freezing chamber 200, it can form frost at the electrodes again, and foods may come in contact with it and be degenerated.

[95] The food product shelf 260 in the supercooling apparatus according to the second embodiment of the present invention serves as a divider or spacer, separating foods in the non-freezing chamber 200 from the bottom of the casing 230. In other words, the food product shelf 260 prevents a contact between foods and the defrost water produced in result of a defrosting process by the defrosting device 250. A support 264 makes sure that a bottom face of the food product shelf where foods are placed is spaced apart from the bottom face of the casing 230. (The food product shelf 260 includes a support 264)

[96] A supercooling apparatus according to yet another embodiment of the present invention may include at least one of a freezer compartment or a refrigerator compartment, and a non-freezing chamber 200 placed in either one. In addition, it does not matter where chilled air being provided to the non-freezing chamber 200, that is, chilled air that inflows via a chilled air hole and a chilled air flow path 220 of a casing, comes from the refrigerator compartment or the freezer compartment, and where the chilled air is discharged. Nevertheless, since chilled air in the refrigerator compartment is still warmer than chilled air in the freezer compartment, it is desirable to invite the chilled air from the freezer compartment to maintain a supercooled state.

[97]

[98] The present invention has been described in detail with reference to the embodiments and the attached drawings. However, the scope of the present invention is not limited to the embodiments and the drawings, but defined by the appended claims.

Claims

[I] A supercooling apparatus, comprising: an electrode unit including a first electrode and a second electrode of different areas arranged to face each other; a storage unit formed between the first electrode and the second electrode; and a chilled air supply unit including a chilled air flow path to supply chilled air to the storage unit.

[2] The supercooling apparatus of claim 1, wherein the first electrode is a hollow- type electrode and the chilled air flow path includes a hollow formed at the first electrode. [3] The supercooling apparatus of claim 1 or claim 2, wherein the second electrode surrounds the first electrode and the storage unit is formed in a space between the first electrode and the second electrode surrounding the same. [4] The supercooling apparatus of claim 1, wherein the first electrode is an active electrode and the second electrode is a ground electrode, the first electrode having a broader area than the second electrode, and the ground electrode being formed facing the center of the active electrode. [5] The supercooling apparatus of claim 4, wherein the active electrode surrounds the ground electrode to form the storage unit. [6] A supercooling apparatus, comprising: a first hollow electrode; a second hollow electrode disposed outside the first electrode, surrounding the same; a non-freezing chamber formed between the first electrode and the second electrode; and a chilled air flow path for guiding chilled air into a storage space through a hollow of the first electrode. [7] The supercooling apparatus of claim 6, further comprising: a power supply for applying a high voltage to the first electrode and/or the second electrode. [8] The supercooling apparatus of claim 6, further comprising: an insulation film coated over an outer face of the first electrode. [9] The supercooling apparatus of claim 6, further comprising: an insulation film coated over an outer face of the second electrode. [10] The supercooling apparatus of claim 6, wherein the chilled air flow path guides chilled air from one end of the first electrode to the other end of the same.

[I I] The supercooling apparatus of claim 10, wherein the chilled air flow path discharges chilled air from the other end of the first electrode into the storage space. [12] The supercooling apparatus of claim 6, wherein one of the first and second electrodes is an active electrode and the other is a ground electrode. [13] A supercooling apparatus, comprising: a container having a storage space to store an item; a refrigeration cycle for cooling the storage space; and an electrode unit including a first electrode and a second electrode of different areas arranged symmetrically in the storage space, thereby keeping the item in a non-frozen state at a phase transition temperature or below. [14] The supercooling apparatus of claim 13, wherein the electrode unit is mounted at an inner lateral side of the container. [15] The supercooling apparatus of claim 13, wherein the first electrode is an active electrode and the second electrode is a ground electrode, the first electrode having a broader area than the second electrode. [16] The supercooling apparatus of claim 15, wherein the ground electrode is formed facing the center of the active electrode. [17] The supercooling apparatus of claim 15 or claim 16, wherein the ground electrode and the active ground are spaced apart by a predetermined gap. [18] A supercooling apparatus, comprising: a storage space for storing an item; a refrigeration cycle for cooling the storage space; and an electrode unit including an active electrode and a ground, counter electrode, for generating an electric field in the storage space, wherein the active electrode surrounds the ground electrode to define the storage space and the item stays in a non-frozen state at a phase transition temperature or below. [19] The supercooling apparatus of claim 18, wherein the active electrode and the ground electrode are spaced apart by a predetermined gap. [20] The supercooling apparatus of claim 18 or claim 19, wherein the active electrode has a cylindrical shape.