WO2008004763A1

WO2008004763A1 - Supercooling apparatus

Info

Publication number: WO2008004763A1
Application number: PCT/KR2007/002681
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
Current assignee: LG Electronics Inc
Priority date: 2006-07-01
Filing date: 2007-06-01
Publication date: 2008-01-10
Anticipated expiration: 2009-01-01
Also published as: KR20080003220A; KR20080003221A; KR100857324B1; WO2008004770A1; WO2008004764A3; KR100850608B1; KR100857325B1; WO2008004771A1; KR100836324B1; KR100882625B1; KR20080003215A; KR20080003217A; KR100935746B1; KR20080003214A; KR100862107B1; WO2008004765A3; KR20080003222A; KR100827883B1; WO2008004762A1; KR20080003228A

Abstract

The present invention discloses a supercooling apparatus with can stably maintain a stored object in a supercooled state for an extended period of time by supplying energy by generating an electric field, and which can employ a thin film electrode as an electrode for generating the electric field. The supercooling apparatus includes a storage vault (110) with a storage space (A) formed therein to store an object, a cooling cycle for supplying the cool air to the storage space, and an energy supply unit including an electrode unit (50c, 50d) made of a metal thin film and mounted in the storage vault (110), and a power source unit (3) for supplying power to the electrode unit (50c, 50d).

Description

SUPERCOOLING APPARATUS

Technical Field

[1] The present invention relates to a supercooling apparatus, and more particularly, to a supercooling apparatus which can stably maintain a stored object in a supercooled state for an extended period of time by supplying energy by generating an electric field, and which can employ a thin film electrode as an electrode for generating the electric field. Background Art

[2] Supercooling means that a molten object or a solid cooled below a phase transition temperature in a balanced state is not changed. Each material has stable states in each temperature. If the temperature is slowly varied, elements of the material maintain the stable states in each temperature and accompany the variations of the temperature. However, if the temperature is sharply varied, the elements cannot be changed into the stable states in each temperature. Therefore, the elements of the material maintain the stable state of the start temperature, or some of the elements fail to be changed into the state of the final temperature.

[3] For example, when water is slowly cooled, it is not frozen temporarily at a temperature below 0°C. However, when water is supercooled, it has a kind of quasi- stable state. As this unstable balanced state is broken even by a slight stimulus, water tends to be changed into a more stable state. That is, if a small piece of material is put into the supercooled liquid, or if the liquid is suddenly shaken, the liquid is directly frozen so that the temperature of the liquid can reach the freezing point. Accordingly, the liquid maintains a stable balanced state at the temperature.

[4] Generally, foods such as vegetables, fruits, meats and beverages are refrigerated or frozen to be kept fresh. Such foods contain liquid elements such as water. If the liquid elements are cooled below a phase transition temperature, they are transited into solid elements after a predetermined time.

[5] A stored object such as water can be maintained in the supercooled state for a short time. However, if moisture may be frozen in the food containing moisture, it is necessary to maintain the food in the supercooled state for an extended period of time so as to keep quality of the food and preserve the food for a long time. Disclosure of Invention Technical Problem [6] An object of the present invention is to provide a supercooling apparatus which can stably maintain a stored object in a supercooled state for an extended period of time.

[7] Another object of the present invention is to provide a supercooling apparatus which can cut down a manufacturing cost of an electrode unit and simplify an installation process of the electrode unit, by forming the electrode unit using a metal thin film.

[8] Yet another object of the present invention is to provide a supercooling apparatus which can prevent phase transition of a stored object and stably maintain the stored object in a supercooled state for an extended period of time through an electrode unit made of a metal thin film and manufactured in various shapes.

[9] Yet another object of the present invention is to provide a supercooling apparatus using an electrode made of an anti-corrosion or anti-oxidization material. Technical Solution

[10] In order to achieve the above-described objects of the invention, there is provided a supercooling apparatus, including: a storage vault with a storage space formed therein to store an object; a cooling cycle for cooling the storage space; and an energy supply unit including an electrode unit made of a metal thin film and mounted in the storage vault, and a power source unit for supplying power to the electrode unit, wherein the object is maintained in a non-frozen state below a phase transition temperature.

[11] Preferably, the electrode unit is symmetrically formed at the top and bottom sides of the storage vault or the left and right sides thereof.

[12] Preferably, the storage vault includes an insulation member surrounding the electrode unit.

[13] Preferably, the electrode unit contains Al.

[14] Preferably, the electrode unit is at least one of a metal layer, a coating layer and a plating layer adhered to the storage vault.

[15] In another aspect of the present invention, a supercooling apparatus includes: a storage vault having a storage space for storing an object, and a thin film electrode layer formed respectively on the inner side faces of the storage space facing each other; a cooling cycle for supplying the cool air to the storage space; and a power source unit for supplying power to the electrode unit, wherein the object is maintained in a non-frozen state below a phase transition temperature. Brief Description of the Drawings

[16] The present invention will become better understood with reference to the ac- companding drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein:

[17] Fig. 1 is a conceptional view illustrating a basic electrode structure of a supercooling apparatus for maintaining a supercooled state;

[18] Fig. 2 is a graph showing a supercooling phenomenon in the supercooling apparatus of Fig. 1;

[19] Fig. 3 is an exemplary view illustrating the supercooling apparatus of Fig. 1 ;

[20] Fig. 4 is a conceptional view illustrating an electrode structure applied to a supercooling apparatus in accordance with the present invention; and

[21] Figs. 5 to 8 are exemplary views illustrating examples of the supercooling apparatus of Fig. 4. Mode for the Invention

[22] A supercooling apparatus in accordance with preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[23] If a liquid, for example, water is slowly cooled, it is not frozen temporarily at a temperature below 0°C. However, when water is supercooled, it has a kind of quasi- stable state. As this unstable balanced state is broken even by a slight stimulus, water tends to be changed into a more stable state. That is, if a small piece of material is put into the supercooled liquid, or if the liquid is suddenly shaken, the liquid is directly frozen so that the temperature of the liquid can reach the freezing point. Accordingly, the liquid maintains a stable balanced state at the temperature.

[24] Even if the temperature is lower than a phase transition temperature, if molecules can continuously perform at least one of rotation, vibration and translation, they can continuously maintain the supercooled state. That is, as soon as cooling which is a process of taking energy from the liquid is conducted, if energy is supplied to prevent phase transition from liquid to solid, the liquid state can be stably maintained for a long time even at a temperature lower than the phase transition temperature. Here, if the process of supplying energy is identical to the process of taking energy, they affect each other. Normally, a cooling apparatus uses a method of taking thermal energy. It is thus inappropriate to adopt a method of suppljing thermal energy.

[25] Fig. 1 is a conceptional view illustrating a basic electrode structure of a supercooling apparatus for maintaining a supercooled state.

[26] Referring to Fig. 1, a casing 1 with a storage space Sl formed therein includes two electrodes 10a and 10b facing the storage space Sl. A power supply unit 2 is provided to apply a high AC voltage to the electrodes 10a and 10b. The power supply unit 2 supplies energy to the storage space Sl between the electrodes 10a and 10b, by generating an electric field in the storage space Sl by applying the high AC voltage to the electrodes 10a and 10b.

[27] In addition, the storage space Sl is cooled by a cooling cycle (not shown). When thermal energy is taken from the storage space Sl, another kind of energy (namely, electric field energy) can be supplied thereto. Accordingly, when water or food containing moisture are stored in the storage space Sl, they can maintain a stable cooling state below a phase transition temperature for an extended period of time without being solidified or frozen.

[28] Fig. 2 is a graph showing a temperature when water kept in the supercooling apparatus of Fig. 1 is cooled. Generally, if water is cooled below a phase transition temperature, it is phase-transited.

[29] 0. lfof distilled water is put into the storage space Sl of the casing 1 of Fig. 1. The electrodes 10a and 10b facing the storage space Sl have wider faces than the storage space Sl. The electrodes 10a and 10b are placed at an interval of 20mm. The casing 1 is made of an acrylic material, and inserted and cooled in a cooling space uniformly supplied with the cool air (namely, a refrigerating apparatus which does not have a supplementary electric field generator except the electrodes 10a and 10b).

[30] Here, the power supply unit 2 applies 0.9 lkV(6.76mA) and 2OkHz of AC voltage to the electrodes 10a and 10b, and the temperature inside the cooling space is about -7 °C.

[31] As shown in Fig. 2, the supercooled state (non-frozen state) can be stably maintained for an extended period of time, by applying energy through the electric field.

[32] Fig. 3 is an exemplary view illustrating the supercooling apparatus of Fig. 1. The supercooling apparatus of Fig. 3 is an indirect-cooling type supercooling apparatus having a cooling cycle.

[33] The supercooling apparatus includes a casing 110 having one open face, a storage space A formed therein, and a shelf 130 for partially partitioning the storage space A, and a door 120 for opening and closing the opened face of the casing 110. A freezing cycle 30 of the indirect cooling type supercooling apparatus includes a compressor 32 for compressing a refrigerant, an evaporator 33 for generating the cool air (Indicated by arrows) for cooling the storage space A or a stored object, a fan 34 for forcibly moving the generated cool air, a suction duct 36 for introducing the cool air into the storage space A, and a discharge duct 38 for inducing the cool air passing through the storage space A to the evaporator 33. Although not illustrated, the freezing cycle 30 may include a condenser, a drier and an expansion device. In the supercooling apparatus, the cooling cycle can be embodied as the direct cooling type as well as the indirect cooling type.

[34] Electrode units 50a and 50b are formed between the inner faces 112a and 112c facing the storage space A and the outer faces of the casing 110. The electrode units 50a and 50b are installed to face the storage space A, for applying an electric field to the whole storage space A. The storage space A is spaced apart from the ends of the electrode units 50a and 50b at predetermined intervals in the inward directions of the electrode units 50a and 50b or the center direction, so that a uniform electric field can be applied to the storage space A or the stored object.

[35] The suction duct 36 and the discharge duct 38 are formed in the inner face 112b of the casing 110. The surfaces of the inner faces 112a, 112b and 112c of the casing 110 are made of a hydrophobic material, and thus are not frozen during a supercooling mode due to reduction of surface tension of water such as moisture. The outer faces and the inner faces 112a, 112b and 112c of the casing 110 are made of an insulation material, for preventing the user from receiving an electric shock from the electrode units 50a and 50b, and preventing the stored object from electrically contacting the electrode units 50a and 50b through the inner faces 112a, 112b and 112c.

[36] In the supercooling apparatus such as a refrigerator, an electrode is normally made of a copperplate. If a temperature variation occurs, the electrode and the electrode- formed insulation material (preferably, the inside of the sidewall or the shelf of the supercooling apparatus) may be separated from each other due to different linear expansion coefficients. In addition, as the electrode unit is bent due to different linear expansion coefficients, the supercooling apparatus cannot attain target distribution of an electric field. If the electrode is made of a copperplate and is not formed in a flat shape, although the electrode is adhered to the insulation material (preferably, the inside of the sidewall or the shelf of the supercooling apparatus), it is bent due to temperature differences. As the electrode has a curvature, it is easily separated from the insulation material. When the electrode made of the copperplate is applied to the supercooling apparatus defining a high humidity space, the electrode is easily corroded or oxidized. A stored object may be contaminated by such corrosion and oxidization.

[37] A manufacturing method of the electrode can be changed to solve the foregoing problems.

[38] Fig. 4 is a conceptional view illustrating an electrode structure applied to a su- percooling apparatus in accordance with the present invention. Electrode units Ia and Ib made of a metal thin film are inserted into insulation materials 2a and 2b, respectively. For example, the electrode units Ia and Ib are printed inside a sidewall or shelf of the supercooling apparatus, and surrounded by the insulation materials 2a and 2b. A power supply device 3 supplies high voltage power to the electrode units Ia and Ib. The electrode units Ia and Ib are preferably coated or plated inside the sidewall or the shelf of the supercooling apparatus. In addition, the electrode units Ia and Ib are preferably made of a metallic material or a flexible material such as an Al tape. If the electrode units Ia and Ib are made of the metallic material, they have high conductivity. If the electrode units Ia and Ib are made of the flexible material, they are neither separated from the inside of the sidewall or the shelf nor bent in spite of contraction or expansion by temperature differences. Moreover, the electrode units Ia and Ib made of the Al material are not corroded and oxidized in a high humidity region, to prevent contamination of a stored object. As the electrode units Ia and Ib are not changed in quality by the corrosion and oxidization, they can stably generate an electric field.

[39] If the electrode is manufactured by printing the metal thin film on the insulation material (preferably, the inner wall or the shelf of the supercooling apparatus), since the metal thin film is very thin, the electrode may be expanded or contracted but is not separated by temperature differences. In addition, the electrode is not bent due to temperature differences, to maintain target distribution of the electric field.

[40] The metal thin film is thinner than the general copperplate and less affected by temperature differences. Therefore, the electrode can be manufactured in various shapes. The electrode unit for supplying energy by generating the electric field can be adhered to a storage vault of the supercooling apparatus by metal layer printing, coating or plating. That is, the manufacturing method of the electrode using the metal thin film can adopt coating and plating as well as printing. The electrode unit can be embodied as a metal layer, a coating layer or a plating layer adhered to the storage vault.

[41] The manufacturing method of the electrode described above is nothing but an example. Any kinds of methods that can adhere the metal thin film to one side face can be used. That is, the metal thin film functioning as the thin film electrode layer can be adhered to the storage vault by printing, coating or plating.

[42] Figs. 5 to 8 are exemplary views illustrating examples of the supercooling apparatus of Fig. 4. Fig. 5 shows an indirect cooling type supercooling apparatus. The su- percooling apparatus of Fig. 5 is identical to the supercooling apparatus described above except the electrode units 50a and 50b. While the electrode units 50a and 50b are made of a copperplate in Fig. 3, electrode units 50c and 50d are made of a metal thin film (preferably, Al tape) in Fig. 5. As mentioned above, even if temperature differences exist in the supercooling apparatus, if the electrode units 50c and 50d are manufactured by printing the metal thin film (preferably, Al tape) inside a casing 112a and 112c of the supercooling apparatus, the electrode units 50c and 50d are neither separated from the casing 112a and 112c nor bent.

[43] Fig. 6 illustrates a direct cooling type supercooling apparatus which includes a cooling cycle having a compressor 32 for compressing a refrigerant, and an evaporator 39 installed in a casing 110, for evaporating the refrigerant. Referring to Fig. 6, provided are an electrode unit 5Oe, and a shelf 130 which is an insulation member surrounding the electrode unit 5Oe. In a process of forming a metal portion in the shelf, it is easier to form a metal thin film (preferably, Al tape) in the shelf than to form a copperplate in the shelf because of small thickness. As described above, even if temperature differences occur in the supercooling apparatus, the electrode unit 50e made of the metal thin film (preferably, Al tape) and surrounded by the shelf 130 is not separated from the shelf 130 in expansion or contraction by temperature differences.

[44] Fig. 7 is a cross-sectional view illustrating a supercooling apparatus. As shown in

Fig. 7, an electrode 13c is formed at the center portion, and a hollow cylindrical electrode 13d surrounds the electrode 13c. The electrode 13c may be a conductive wire or a cylindrical or hollow cylindrical electrode.

[45] The supercooling apparatus includes a device for cooling an object such as a cooling cycle having a compressor 32 for compressing a refrigerant, and an evaporator 39 installed in a casing 110, for evaporating the refrigerant, and a device for supplying energy. In this case, the electrode unit is placed to maintain a supercooled state by generating a strong electric field toward the center portion and intensively supplying energy to a specific region.

[46] In this supercooling apparatus, the electrode is not flat but has a curvature. If the electrode is made of a copperplate, the electrode 13c or the hollow cylindrical electrode 13d may be easily separated or bent due to temperature differences. Such separation or bending prevents the electrode from maintaining the supercooled state by generating a strong electric field toward the center portion and intensively supplying energy to a specific region as designed. However, if the electrode is manufactured by printing a metal thin film (preferably, Al tape) in a container, the electrode is not affected by the curvature.

[47] Moreover, it is easier to form the electrode unit by using the metal thin film than the copperplate. As the electrode unit is not separated in expansion or contraction by temperature differences, the electrode unit can generate a designed type of electric field. If the electrodes 13c and 13d are made of a more flexible material among the metal thin films than the copperplate, it is easier to manufacture the electrode with the curvature by using the metal thin film than the copperplate.

[48] Fig. 8 is another cross-sectional view illustrating the supercooling apparatus of Fig.

7. The supercooling apparatus also includes an evaporator (not shown) for evaporating a refrigerant, and a compressor (not shown) for compressing the refrigerant. If an electrode 13c placed at the center portion is cylindrical or hollow cylindrical, expansion or contraction by temperature differences becomes a more serious problem due to a curvature. A hollow cylindrical electrode 13d surrounding the electrode 13c is in the same situation. If the electrode is made of a copperplate, it may be easily separated or bent due to temperature differences. Such separation or bending prevents the electrode from maintaining a supercooled state by generating a strong electric field toward the center portion and intensively supplying energy to a specific region as designed.

[49] However, if the electrode is manufactured by printing a metal thin film (preferably,

Al tape) in a container, the electrode is not affected by the curvature. In addition, it is easier to form the electrode unit by using the metal thin film than the copperplate. As the electrode unit is not separated in expansion or contraction by temperature differences, the electrode unit can generate a designed type of electric field. If the electrodes 13c and 13d are made of a more flexible material among the metal thin films than the copperplate, it is easier to manufacture the electrode with the curvature by using the metal thin film than the copperplate. Industrial Applicability

[50] The present invention can stably maintain the stored object in the supercooled state for the extended period of time.

[51] The present invention can cut down the manufacturing cost of the electrode unit and simplify the installation process of the electrode unit, by forming the electrode unit by using the metal thin film. As the electrode unit is neither separated nor bent in spite of temperature differences of the supercooling apparatus, the electrode unit can generate the electric field as designed.

[52] The present invention can prevent phase transition of the stored object and stably maintain the stored object in the supercooled state for the extended period of time through the electrode unit made of the metal thin film and manufactured in various shapes.

[53] The present invention can stably perform the non-freezing operation and prevent contamination of the stored object, by using the electrode made of the anti-corrosion or anti-oxidization material.

[54] Although the preferred embodiments of the present invention have been described, it is understood that the present invention should not be limited to these preferred embodiments bat various changes and modifications can be made by one skilled in the art within the spirit and scope of the present invention as hereinafter claimed.

[55]

Claims

[1] A supercooling apparatus, comprising: a storage vault with a storage space formed therein to store an object; a cooling cycle for cooling the storage space; and an energy supply unit including an electrode unit made of a metal thin film and mounted in the storage vault, and a power source unit for supplying power to the electrode unit, wherein the object is maintained in a non-frozen state below a phase transition temperature.

[2] The supercooling apparatus of claim 1, wherein the electrode unit is symmetrically formed at the top and bottom sides of the storage vault or the left and right sides thereof.

[3] The supercooling apparatus of claim 2, wherein the storage vault comprises an insulation member surrounding the electrode unit.

[4] The supercooling apparatus of any one of claims 1 to 3, wherein the electrode unit contains Al.

[5] The supercooling apparatus of any one of claims 1 to 3, wherein the electrode unit is at least one of a metal layer, a coating layer and a plating layer adhered to the storage vault.

[6] The supercooling apparatus of any one of claims 1 to 3, wherein the electrode unit is made of a flexible material.

[7] A supercooling apparatus, comprising: a storage vault including a storage space for storing an object, and a thin film electrode layer formed respectively on the inner side faces of the storage space facing each other; a cooling cycle for cooling the storage space; and a power source unit for supplying power to the electrode unit, wherein the object is maintained in a non-frozen state below a phase transition temperature.

[8] The supercooling apparatus of claim 7, wherein the thin film electrode layer is adhered to the storage vault.

[9] The supercooling apparatus of claim 7, wherein the storage vault comprises an insulation member surrounding the thin film electrode layer.

[10] The supercooling apparatus of any one of claims 7 to 9, wherein the electrode layer is a metal layer containing Al.

[11] The supercooling apparatus of any one of claims 7 to 9, wherein the thin film electrode layer is made of a flexible material.