refrigerator

Abstract

To provide a refrigerator which inhibits frost formation on a cooler to eliminate a need to perform defrosting operation or reduce the frequency of the defrosting operation.SOLUTION: A refrigerator 10 includes: a storage chamber; a cooler chamber 40 in which a cooler 41 for cooling air flowing from the storage chamber is installed; and a cool air circulating fan 43 which sends cool air cooled by the cooler 41 to the storage chamber. A dehumidification device 50 is installed in at least one of the storage chamber and the cooler chamber 40. The dehumidification device 50 has: a honeycomb structure 51 which has an outer peripheral wall 52, and a partition wall 55 which is disposed at the inner side of the outer peripheral wall 52 and defines a plurality of cells 54 forming a passage extending from a first end surface 53a to a second end surface 53b and in which at least the partition wall 55 is made of a material having PTC characteristics; and a dehumidification layer 56 formed on a surface of the partition wall 55 and including an adsorbent capable of adsorbing steam.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a refrigerator. [Background technology]

[0002] Moisture in the air that flows into the refrigerator and moisture that evaporates from food condenses in the cooler and then grows as frost. Since the frost that grows in the cooler reduces the cooling performance, a defrosting operation is periodically performed to melt and remove the frost that has adhered to the cooler using a heating means such as a heater.

[0003] However, since the defrosting operation is a factor that increases the power consumption of a refrigerator, a method for efficiently performing the defrosting operation has been proposed. For example, Patent Document 1 proposes a refrigerator including a cold air supplying means for supplying cold air to a storage compartment in a refrigeration temperature range, a cooler for cooling the storage compartment in the refrigeration temperature range, a refrigeration cycle formed by connecting the cooler, a compressor, a radiator, and a throttle with a refrigerant pipe, a temperature detecting means provided in a part of the refrigerant pipe of the cooler, and a heating means for heating the cooler, characterized in that after the compressor is stopped, the cold air is circulated by the cold air supplying means for a predetermined time, and then the heating means is controlled based on the temperature detected by the temperature detecting means. This refrigerator can predict the amount of frost before performing the defrosting operation, so that the amount of power consumed by the heater heating in the defrosting operation can be reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-7510 A Summary of the Invention [Problem to be solved by the invention]

[0005] The refrigerator described in Patent Document 1 can reduce power consumption by reducing the frequency of defrosting operations, but cannot prevent frost formation on the cooler. In addition, the defrosting operation changes the temperature inside the refrigerator due to the heating by the heating means (heater), and may cause deterioration of food stored in the refrigerator, so it is desirable to reduce the number of defrosting operations as much as possible.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a refrigerator that suppresses frost formation on a cooler and eliminates or reduces the need for defrosting operation. [Means for solving the problem]

[0007] The present inventors have conducted extensive research into a refrigerator that includes a storage compartment, a cooler compartment in which a cooler that cools air flowing in from the storage compartment is installed, and a cool air circulating fan that blows the cool air cooled by the cooler into the storage compartment, and have found that the above-mentioned problems can be solved by installing a dehumidifying device having a predetermined structure at a predetermined position, thereby completing the present invention. That is, the present invention is exemplified as follows.

[0008] [1] A storage compartment, a cooling compartment in which a cooling device that cools air flowing in from the storage compartment is installed, and a cooling air circulation fan that blows the cold air cooled by the cooling device into the storage compartment; A dehumidifying device is installed in at least one of the storage chamber and the cooler chamber; The dehumidifying device includes a honeycomb structure having an outer peripheral wall and partition walls arranged inside the outer peripheral wall and defining a plurality of cells that serve as flow paths extending from a first end face to a second end face, the partition walls being made of a material having PTC characteristics, and a dehumidifying layer formed on a surface of the partition walls and containing an adsorbent capable of adsorbing water vapor.

[0009] [2] The refrigerator according to [1], wherein the storage compartment includes at least a refrigerator compartment and a freezer compartment, and the storage compartment in which the dehumidifying device is installed is the freezer compartment.

[0010] [3] The refrigerator according to [1] or [2], wherein the dehumidifying device is installed in a dehumidifying compartment adjacent to at least one of the storage compartment and the cooling compartment and separated by an internal opening and closing door.

[0011] [4] The refrigerator described in [3], wherein the dehumidification chamber is located on at least one of the side of the storage chamber and the back of the cooling chamber.

[0012] [5] The refrigerator described in [4], wherein the dehumidification chamber is arranged at the rear of the cooling chamber on an upstream side of the cooling chamber in the air flow.

[0013] [6] The refrigerator according to any one of [3] to [5], wherein the dehumidifying chamber has two openings through which outside air can circulate, and an external opening door is disposed at each opening.

[0014] [7] The refrigerator further includes a control unit that controls the dehumidifying device, the internal opening / closing door, and the external opening / closing door. The refrigerator described in [6], wherein the control unit is controlled to open the internal opening / closing door and close the external opening / closing door to perform dehumidification using the dehumidification device, and to close the internal opening / closing door, open the external opening / closing door, and regenerate the dehumidification device by applying a voltage to the dehumidification device to heat it.

[0015] [8] The refrigerator described in [7], wherein an outdoor air circulation fan is arranged in the dehumidification chamber, and the control unit is configured to drive the outdoor air circulation fan when the dehumidification device is regenerated.

[0016] [9] The refrigerator according to any one of [1] to [8], wherein the adsorbent is capable of adsorbing odorous components in addition to the water vapor.

[0017]

[10] The refrigerator according to any one of [1] to [9], wherein the adsorbent is capable of absorbing moisture at an absolute humidity of 4 g / kg (DA) or less on a psychrometric chart under atmospheric pressure. Effect of the Invention

[0018] According to the present invention, it is possible to provide a refrigerator that suppresses frost formation on a cooler and eliminates the need for or reduces the need to perform a defrosting operation. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of a central cross section of a refrigerator according to an embodiment of the present invention. [Diagram 2] FIG. 11 is a schematic cross-sectional view of the periphery of a dehumidifying chamber 60 in another refrigerator according to an embodiment of the present invention. [Figure 3A] 1 is a schematic diagram of a cross section parallel to a flow path direction of a dehumidifying device used in a refrigerator according to an embodiment of the present invention. [Figure 3B] 3B is a schematic cross-sectional view of the dehumidification device of FIG. 3A taken along line aa'. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] A refrigerator according to an embodiment of the present invention includes a storage compartment, a cooler compartment in which a cooler for cooling air flowing in from the storage compartment is installed, and a cool air circulation fan for blowing the cool air cooled by the cooler into the storage compartment. At least one of the storage compartment and the cooler compartment is installed with a dehumidifying device. The dehumidifying device includes a honeycomb structure having an outer peripheral wall and partition walls arranged inside the outer peripheral wall and defining a plurality of cells that become flow paths extending from a first end face to a second end face, and at least the partition walls are made of a material having a PTC characteristic, and a dehumidifying layer formed on the surface of the partition walls and containing an adsorbent capable of adsorbing water vapor. With this configuration, frost formation on the cooler can be suppressed, and the implementation of a defrosting operation can be unnecessary or reduced. Therefore, the amount of power consumption required for the defrosting operation can be reduced compared to conventional refrigerators. In addition, since the temperature inside the refrigerator is less likely to change due to the defrosting operation, deterioration of food stored in the refrigerator can be suppressed, and food waste can be reduced. Furthermore, the refrigerator according to the embodiment of the present invention can eliminate the need to perform a defrosting operation, and therefore it is also possible to remove devices necessary for the defrosting operation (for example, a heater, a control mechanism, etc.).

[0021] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements to the following embodiments, which are made based on the ordinary knowledge of a person skilled in the art, fall within the scope of the present invention, without departing from the spirit of the present invention.

[0022] FIG. 1 is a schematic diagram of a central cross section of a refrigerator according to an embodiment of the present invention. The refrigerator 10 includes an insulated box 11 as a main body, and a storage compartment capable of storing food and the like is formed inside the insulated box 11. As the storage compartments, a refrigerator compartment 12 is formed on the upper level, and a freezer compartment 13 is formed on the lower level. Note that, although an example having one refrigerator compartment 12 and one freezer compartment 13 is shown in FIG. 1, other storage compartments such as a vegetable compartment and an ice compartment may be present, and the number of these storage compartments is not particularly limited. In addition, the positions of the refrigerator compartment 12 and the freezer compartment 13 are not particularly limited, and the freezer compartment 13 may be formed on the upper level and the refrigerator compartment 12 on the lower level.

[0023] The front opening of the refrigerator compartment 12 is closed by an insulated door 20, and the front opening of the freezer compartment 13 is closed by an insulated door 21. The insulated doors 20, 21 are generally revolving doors and have the same insulating structure as the insulated box body 11. The refrigerator compartment 12 and the freezer compartment 13 are separated by an insulated wall 30. The insulated wall 30 has the same insulating structure as the insulated box body 11.

[0024] A cooling chamber 40 is defined behind the freezer chamber 13. A cooling chamber 41 (evaporator) for cooling the air flowing in from the storage chamber (freezer chamber 13) is disposed inside the cooling chamber 40. A compressor 42 is disposed behind the lower stage of the refrigerator 10. The cooling chamber 41 is connected to the compressor 42, a condenser (not shown) and an expansion means (not shown) via refrigerant piping (not shown) to constitute a vapor compression refrigeration cycle circuit.

[0025] A cold air circulation fan 43 is disposed above the cooler chamber 40, which blows the cold air cooled by the cooler 41 to the storage chambers (the refrigerator chamber 12 and the freezer chamber 13). The cold air circulation fan 43 may be, for example, an axial flow fan or a centrifugal fan.

[0026] When the cool air circulation fan 43 is operated, part of the cool air cooled by the cooler 41 rises through the air passage 14 and is blown out from the air outlet 15 into the refrigerator compartment 12. Also, part of the cool air cooled by the cooler 41 is blown out from the air outlet 16 into the freezer compartment 13. This causes the refrigerator compartment 12 and the freezer compartment 13 to be cooled to a predetermined temperature. The air blown into the refrigerator compartment 12 returns to the cooler compartment 40 through a return air passage (not shown) that connects the refrigerator compartment 12 and the cooler compartment 40. Also, the air blown into the freezer compartment 13 returns to the cooler compartment 40 through the return air passage 17.

[0027] A dehumidifying device 50 is installed in the cooling chamber 40. The dehumidifying device 50 has a function of dehumidifying the air flowing to the cooler 41. Therefore, by disposing the dehumidifying device 50, it is possible to suppress frost formation on the cooler 41 and eliminate or reduce the need to perform a defrosting operation. Although FIG. 1 shows an example in which the dehumidifying device 50 is provided in the cooler chamber 40, the dehumidifying device 50 may be provided in a storage chamber. Also, the dehumidifying device 50 may be provided in both the cooler chamber 40 and the storage chamber. The storage chamber in which the dehumidifying device 50 is provided is preferably the freezer chamber 13. Even when the dehumidifying device 50 is provided in these positions, it is possible to suppress frost formation on the cooler 41, and to eliminate or reduce the need to perform a defrosting operation.

[0028] The dehumidifying device 50 is preferably installed in a dehumidifying chamber 60 adjacent to at least one of the storage chamber and the cooler chamber 40 and separated by an internal opening and closing door 61. With this configuration, when the internal opening and closing door 61 is opened, the dehumidifying device 50 can dehumidify the air in the refrigerator 10 (particularly, the storage chamber and / or the cooler chamber 40). The internal opening and closing door 61 is not particularly limited as long as it is a door that can open and close the flow path through which air flows. As the internal opening and closing door 61, a known opening and closing door such as a shutter door or a movable louver door can be used.

[0029] The dehumidifying chamber 60 has an opening through which outside air can flow, and an exterior opening / closing door 62 can be disposed at the opening. With this configuration, when the exterior opening / closing door 62 is opened, the dehumidifying device 50 can be regenerated (water vapor adsorbed from the air inside the refrigerator 10 can be released to the outside). In particular, since the amount of water vapor adsorbed by the dehumidifying layer 56 of the dehumidifying device 50 is not large, the dehumidifying device 50 can be easily regenerated simply by opening the exterior opening / closing door 62. However, the regeneration of the dehumidifying device 50 may be promoted by applying a voltage to the dehumidifying device 50 to heat it. The exterior opening / closing door 62 is closed when the dehumidifying device 50 is used to dehumidify the air inside the refrigerator 10. The interior opening / closing door 61 is closed when the dehumidifying device 50 is being regenerated. The exterior opening / closing door 62 is not particularly limited as long as it is a door that can open and close the flow path through which air flows, similar to the interior opening / closing door 61. As the exterior opening / closing door 62, a known opening / closing door such as a shutter door or a movable louver door can be used.

[0030] The dehumidifying chamber 60 is preferably disposed on at least one of the side surface of the storage chamber and the back surface of the cooler chamber 40. By providing the dehumidifying chamber 60 in such a position, it is possible to easily connect the inside and outside of the storage chamber and the cooler chamber 40. The side surface of the storage chamber and the back surface of the cooler chamber 40 are formed of the heat-insulating box 11. Therefore, the dehumidifying chamber 60 may be formed by providing an opening in a part of the heat-insulating box 11 and arranging the dehumidifying device 50, the inner opening door 61, and the outer opening door 62 in the opening.

[0031] The dehumidifying chamber 60 is preferably disposed at the rear of the cooler chamber 40, upstream of the cooler 41 in the air flow. By providing the dehumidifying chamber 60 at such a position, it is possible to stably reduce the moisture in the air flowing to the cooler 41. Therefore, since frost formation on the cooler 41 is stably suppressed, it is possible to eliminate or reduce the need to perform a defrosting operation.

[0032] The dehumidifying chamber 60 has two openings through which outside air can circulate, and each opening may be provided with an external opening door 62. A schematic cross-sectional view of the periphery of the dehumidifying chamber 60 having such a structure is shown in Fig. 2. In Fig. 2, (a) shows the dehumidifying device 50 in the dehumidifying mode, and (b) shows the dehumidifying device 50 in the regeneration mode. The arrows in Fig. 2 indicate the direction of air flow. In the dehumidification mode of the dehumidifying device 50, as shown in (a), the internal opening / closing door 61 is opened and the external opening / closing door 62 is closed. In this state, the air in the refrigerator 10 flows through the dehumidifying device 50, and dehumidification is performed by the dehumidifying device 50. On the other hand, in the regeneration mode of the dehumidifying device 50, as shown in (b), the internal opening / closing door 61 is closed and the external opening / closing door 62 is opened. Then, by driving the outside air circulation fan 63 provided in the dehumidifying chamber 60, the outside air flows through the dehumidifying device 50, and the dehumidifying device 50 is regenerated. At this time, the regeneration of the dehumidifying device 50 may be promoted by applying a voltage to the dehumidifying device 50 to heat it.

[0033] The refrigerator 10 may further include a control unit (not shown) that controls the dehumidifying device 50, the inner opening / closing door 61, and the outer opening / closing door 62. The control unit is preferably controlled so as to open the internal opening / closing door 61 and close the external opening / closing door 62 to perform dehumidification by the dehumidifying device 50, and also to close the internal opening / closing door 61 and open the external opening / closing door 62, and to apply a voltage to the dehumidifying device 50 to heat it, thereby regenerating the dehumidifying device 50. By providing such a control unit, the dehumidifying device 50 can be efficiently operated in the dehumidification mode and the regeneration mode. Moreover, the control unit is preferably configured to drive the outside air circulation fan 63 when regenerating the dehumidifying device 50. By controlling the outside air circulation fan 63 in this manner, the dehumidifying device 50 can be regenerated efficiently. The control unit may include, but is not limited to, a CPU that executes various types of calculation processing, a ROM that stores the programs and data necessary for the control, a RAM that temporarily stores the results of calculations by the CPU, and an input / output port for inputting and outputting signals to and from the outside.

[0034] Fig. 3A is a schematic diagram of a cross section parallel to the flow path direction of a dehumidifying device used in a refrigerator according to an embodiment of the present invention, and Fig. 3B is a schematic diagram of a cross section taken along line a-a' in the dehumidifying device of Fig. 3A. 3A and 3B, the dehumidifying device 50 includes a honeycomb structure 51 having an outer peripheral wall 52, partition walls 55 disposed inside the outer peripheral wall 52 and defining a plurality of cells 54 that serve as flow paths extending from a first end face 53a to a second end face 53b, and a dehumidifying layer 56 formed on the surface of the partition walls 55. In the honeycomb structure 51, at least the partition walls 55 are made of a material having a PTC (Positive Temperature Coefficient) characteristic. The dehumidifying layer 56 contains an adsorbent capable of adsorbing water vapor. Moreover, the dehumidifying device 50 may further include a pair of electrodes 57a, 57b provided on the honeycomb structure 51, if necessary. Moreover, the dehumidifying device 50 may further include a terminal 58 connected to the pair of electrodes 57a, 57b, if necessary. However, it should be noted that when the dehumidifying device 50 is regenerated without heating, the pair of electrodes 57a, 57b and the terminal 58 are not necessary.

[0035] The shape of the honeycomb structure 51 is not particularly limited. For example, the outer shape of a cross section perpendicular to the flow path direction (the direction in which the cells 54 extend) of the honeycomb structure 51 can be a polygon such as a quadrangle (rectangle, square), pentagon, hexagon, heptagon, or octagon, a circle, or an oval shape (egg, ellipse, oval, rounded rectangle, etc.). The end faces (first end face 53a and second end face 53b) have the same shape as the cross section. When the cross section and the end faces are polygonal, the corners may be chamfered.

[0036] The shape of the cells 54 is not particularly limited, but may be a polygon such as a square, pentagon, hexagon, heptagon, or octagon, a circle, or an oval in a cross section perpendicular to the flow direction of the honeycomb structure 51. These shapes may be used alone or in combination of two or more. Among these shapes, a square or hexagon is preferable.

[0037] The honeycomb structure 51 may be a honeycomb joined body having a plurality of honeycomb segments and a joining layer joining the outer peripheral side surfaces of the plurality of honeycomb segments together. The bonding layer can be formed using a bonding material. The bonding material is not particularly limited, but a ceramic material with a solvent such as water added thereto to form a paste can be used. The bonding material may contain a material having PTC properties, or may contain the same material as the outer peripheral wall 52 and the partition walls 55. In addition to the role of bonding the honeycomb segments together, the bonding material can also be used as an outer peripheral coating material after bonding the honeycomb segments.

[0038] From the viewpoints of ensuring the strength of the honeycomb structure 51, the amount of adsorbent carried, and the contact area between the air and the dehumidification layer 56, it is desirable to suitably combine the thickness of the partition walls 55, the cell density, and the cell pitch (or the opening ratio of the cells 54). In this specification, cell density is a value obtained by dividing the number of cells by the area of ​​one end face (first end face 53a or second end face 53b) of the honeycomb structure 51 (the total area of ​​the partition walls 55 and cells 54 excluding the outer wall 52). In this specification, the cell pitch refers to a value calculated by the following calculation. First, the area per cell is calculated by dividing the area of ​​one end face (first end face 53a or second end face 53b) of the honeycomb structure 51 (the total area of ​​the partition walls 55 and the cells 54 excluding the outer peripheral wall 52) by the number of cells. Next, the square root of the area per cell is calculated, and this is defined as the cell pitch. In this specification, the opening ratio of the cells 54 is a value obtained by dividing the total area of ​​the cells 54 partitioned by the partition walls 55 in a cross section perpendicular to the flow direction of the honeycomb structure 51 by the area of ​​one end face (the first end face 53a or the second end face 53b) (the total area of ​​the partition walls 55 and the cells 54 excluding the outer peripheral wall 52). Note that when calculating the opening ratio of the cells 54, the pair of electrodes 57a, 57b and the dehumidification layer 56 are not taken into consideration.

[0039] In an embodiment advantageous from the viewpoint of supporting a sufficient amount of adsorbent, the thickness of the partition wall 55 is 0.30 mm or less, and the cell density is 100 cells / cm 2 In a preferred embodiment, the thickness of the partition wall 55 is 0.20 mm or less, and the cell density is 70 cells / cm. 2 In a more preferred embodiment, the thickness of the partition wall 55 is 0.13 mm or less, and the cell density is 65 cells / cm. 2 and the cell pitch is 1.3 mm or more.

[0040] From the viewpoint of ensuring the strength of the honeycomb structure 51 and keeping the electrical resistance low, the lower limit of the thickness of the partition walls 55 is preferably 0.010 mm or more, more preferably 0.020 mm or more, and further preferably 0.030 mm or more. From the viewpoints of ensuring the strength of the honeycomb structure 51, keeping the electrical resistance low, and increasing the surface area to promote reaction, adsorption, and desorption, the lower limit of the cell density is 30 cells / cm. 2 Preferably, 35 cells / cm or more. 2 More preferably, 40 cells / cm or more. 2 More preferably, it is equal to or greater than this. From the viewpoints of ensuring the strength of the honeycomb structure 51, maintaining low electrical resistance, and increasing the surface area to promote reaction, adsorption, and desorption, the upper limit of the cell pitch is preferably 2.0 mm or less, more preferably 1.8 mm or less, and even more preferably 1.6 mm or less.

[0041] From the viewpoint of ensuring the strength of the honeycomb structure 51, the upper limit of the opening ratio of the cells 54 is preferably 0.94 or less, more preferably 0.92 or less, and further preferably 0.90 or less.

[0042] The thickness of the peripheral wall 52 is not particularly limited, but is preferably determined based on the following viewpoints. First, from the viewpoint of reinforcing the honeycomb structure 51, the thickness of the peripheral wall 52 is preferably 0.05 mm or more, more preferably 0.06 mm or more, and even more preferably 0.08 mm or more. On the other hand, from the viewpoint of increasing the electrical resistance and suppressing the initial current, the thickness of the peripheral wall 52 is preferably 1.0 mm or less, more preferably 0.5 mm or less, even more preferably 0.4 mm or less, and even more preferably 0.3 mm or less. In this specification, the thickness of the peripheral wall 52 refers to the length in the normal direction of the side surface of the honeycomb structure 51 from the boundary between the peripheral wall 52 and the most peripheral cell 54 or partition wall 55 to the side surface of the honeycomb structure 51 in a cross section perpendicular to the flow direction of the honeycomb structure 51.

[0043] The length of the honeycomb structure 51 in the flow path direction and the cross-sectional area perpendicular to the flow path direction are not particularly limited and may be adjusted according to the required size of the dehumidification device 50. For example, when used in a compact dehumidification device 50 while ensuring a predetermined function, the honeycomb structure 51 has a length in the flow path direction of 2 to 20 mm and a cross-sectional area perpendicular to the flow path direction of 10 cm. 2 The upper limit of the cross-sectional area perpendicular to the flow path direction is not particularly limited, but may be, for example, 300 cm 2 The following is the result.

[0044] The partition walls 55 constituting the honeycomb structure 51 are made of a material capable of generating heat when electricity is applied thereto, specifically, made of a material having a PTC characteristic. If necessary, the outer peripheral wall 52 may also be made of a material having a PTC characteristic like the partition walls 55. With this configuration, it is possible to directly heat the dehumidifying layer 56 by heat transfer from the partition walls 55 (and the outer peripheral wall 52, if necessary) which generate heat. In addition, a material having a PTC characteristic has a characteristic that, when the temperature rises and exceeds the Curie point, the resistance value rises rapidly and it becomes difficult for electricity to flow. Therefore, when the partition walls 55 (and the outer peripheral wall 52, if necessary) become hot, the current flowing therethrough is limited, so that excessive heat generation in the honeycomb structure 51 is suppressed. Therefore, it is also possible to suppress thermal deterioration of the dehumidifying layer 56 caused by excessive heat generation.

[0045] From the viewpoint of obtaining an appropriate heat generation, the lower limit of the volume resistivity of the material having the PTC characteristics at 25°C is preferably 0.5 Ω·cm or more, more preferably 1 Ω·cm or more, and even more preferably 5 Ω·cm or more. From the viewpoint of generating heat at a low driving voltage, the upper limit of the volume resistivity of the material having the PTC characteristics at 25°C is preferably 30 Ω·cm or less, more preferably 18 Ω·cm or less, and even more preferably 16 Ω·cm or less. In this specification, the volume resistivity of the material having the PTC characteristics at 25°C is measured in accordance with JIS K6271:2008.

[0046] From the viewpoint of being able to generate heat when electricity is applied and having PTC characteristics, the outer peripheral wall 52 and the partition wall 55 are preferably made of a material mainly composed of barium titanate (BaTiO3). This material is more preferably a ceramic made of a material mainly composed of barium titanate (BaTiO3)-based crystal particles in which part of Ba is replaced with a rare earth element. In this specification, the term "main component" means a component that accounts for more than 50 mass% of the total components. The content of BaTiO3-based crystal particles can be determined by fluorescent X-ray analysis. Other crystal particles can also be measured in the same manner.

[0047] The composition formula of BaTiO3-based crystal particles in which part of Ba is replaced by rare earth elements is (Ba 1-x A x )TiO3, where A represents one or more rare earth elements and 0.0001≦x≦0.010. A is not particularly limited as long as it is a rare earth element, but is preferably one or more selected from the group consisting of La, Ce, Pr, Nd, Eu, Gd, Dy, Ho, Er, Y and Yb, and more preferably La. x is preferably 0.001 or more, more preferably 0.0015 or more, from the viewpoint of suppressing the electrical resistance at room temperature from becoming too high. On the other hand, x is preferably 0.009 or less, from the viewpoint of suppressing the electrical resistance at room temperature from becoming too high due to insufficient sintering. The content of BaTiO3-based crystal particles in the ceramics, in which a part of Ba is replaced by a rare earth element, is not particularly limited as long as it is the amount that serves as the main component, but is preferably 90 mass% or more, more preferably 92 mass% or more, and even more preferably 94 mass% or more. The upper limit of the content of BaTiO3-based crystal particles is not particularly limited, but is generally 99 mass%, preferably 98 mass%. The content of the BaTiO3 crystal particles can be measured by fluorescent X-ray analysis. Other crystal particles can also be measured in the same manner.

[0048] From the viewpoint of reducing the environmental load, it is desirable that the material used for the outer peripheral wall 52 and the partition wall 55 does not substantially contain lead (Pb). Specifically, the outer peripheral wall 52 and the partition wall 55 have a Pb content of preferably 0.01 mass% or less, more preferably 0.001 mass% or less, and even more preferably 0 mass%. The Pb content in the outer peripheral wall 52 and the partition wall 55, calculated as PbO, is preferably less than 0.03 mass%, more preferably less than 0.01 mass%, and even more preferably 0 mass%. The lead content can be determined by ICP-MS (inductively coupled plasma mass spectrometry).

[0049] The Curie points of the materials constituting the outer peripheral wall 52 and the partition walls 55 are preferably in a temperature range in which the resistance value becomes at least twice the resistance at room temperature (25° C.). If the Curie points are in such a temperature range, the current flowing through them is limited when the dehumidifying device 50 becomes hot, so that excessive heat generation in the dehumidifying device 50 is efficiently suppressed. Therefore, thermal deterioration of the dehumidifying layer 56 caused by excessive heat generation can be suppressed. The lower limit of the Curie point of the material constituting the outer peripheral wall 52 and the partition wall 55 is preferably 80° C. or higher, more preferably 100° C. or higher, even more preferably 110° C. or higher, and particularly preferably 125° C. or higher, from the viewpoint of efficiently heating the dehumidifying layer 56. Meanwhile, the upper limit of the Curie point is preferably 200° C. or lower, more preferably 190° C. or lower, even more preferably 180° C. or lower, and particularly preferably 150° C. or lower, from the viewpoint of safety.

[0050] The Curie point of the material constituting the outer peripheral wall 52 and the partition wall 55 can be adjusted by the type and amount of the shifter added. For example, the Curie point of barium titanate (BaTiO3) is about 120°C, but by substituting a part of Ba and Ti with one or more of Sr, Sn, and Zr, the Curie point can be shifted to the lower temperature side.

[0051] In this specification, the Curie point is measured by the following method. A sample is attached to a sample holder for measurement and placed in a measurement tank (e.g., MINI-SUBZERO MC-810P, manufactured by Espec Corporation), and the change in electrical resistance of the sample relative to the temperature change when the temperature is raised from 10°C is measured using a DC resistance meter (e.g., multimeter 3478A, manufactured by Yokogawa Hewlett Packard, Ltd.). The temperature at which the resistance value is twice the resistance value at room temperature (20°C) based on the electrical resistance-temperature plot obtained by the measurement is taken as the Curie point.

[0052] The positions of the pair of electrodes 57a, 57b are not particularly limited, but may be provided on the first end face 53a and the second end face 53b as shown in Fig. 3A. The pair of electrodes 57a, 57b may also be provided on a pair of outer peripheral walls 52 parallel to the extension direction of the cells 54. By applying a voltage between the pair of electrodes 57a and 57b, it becomes possible to cause the honeycomb structure 51 to generate heat by Joule heat.

[0053] The pair of electrodes 57a, 57b is not particularly limited, and may be, for example, a metal or alloy containing at least one selected from Cu, Ag, Al, Ni, and Si. An ohmic electrode capable of making ohmic contact with the outer peripheral wall 52 and / or the partition wall 55 having PTC characteristics may also be used. The ohmic electrode may be, for example, an ohmic electrode containing at least one selected from Al, Au, Ag, and In as a base metal and at least one selected from Ni, Si, Zn, Ge, Sn, Se, and Te for n-type semiconductors as a dopant. The pair of electrodes 57a, 57b may have a single-layer structure or a laminated structure of two or more layers. When the pair of electrodes 57a, 57b has a laminated structure of two or more layers, the materials of the layers may be the same or different.

[0054] The thickness of the pair of electrodes 57a, 57b can be appropriately set depending on the method for forming the pair of electrodes 57a, 57b. Examples of the method for forming the pair of electrodes 57a, 57b include metal deposition methods such as sputtering, vapor deposition, electrolytic deposition, and chemical deposition. The pair of electrodes 57a, 57b can also be formed by applying an electrode paste and then baking it, or by thermal spraying. Furthermore, the pair of electrodes 57a, 57b may be formed by joining metal plates or alloy plates.

[0055] The thickness of the pair of electrodes 57a, 57b is preferably about 5 to 30 μm for baking of electrode paste, about 100 to 1000 nm for dry plating such as sputtering and vapor deposition, about 10 to 100 μm for thermal spraying, and about 5 to 30 μm for wet plating such as electrolytic deposition and chemical deposition. In addition, in joining metal or alloy plates, the thickness is preferably about 5 to 100 μm.

[0056] The terminal 58 is connected to the pair of electrodes 57a, 57b and is provided on at least a part of the pair of electrodes 57a, 57b. The provision of the terminal 58 facilitates connection to an external power source. The terminal 58 is connected to a conductor connected to the external power source.

[0057] The material of the terminal 58 is not particularly limited, but may be, for example, a metal. As the metal, a simple metal or an alloy may be adopted, but from the viewpoint of corrosion resistance, electrical resistivity, and linear expansion coefficient, an alloy containing at least one selected from the group consisting of Cr, Fe, Co, Ni, Cu, Al, and Ti is preferable, and stainless steel, Fe-Ni alloy, and phosphor bronze are more preferable.

[0058] The size and shape of the terminal 58 are not particularly limited. For example, as shown in Fig. 3A, the terminal 58 may be provided on the entire pair of electrodes 57a, 57b on the outer peripheral wall 52. The terminal 58 may be provided on a part of the pair of electrodes 57a, 57b on the outer peripheral wall 52, or may be provided so as to extend outward beyond the outer edge of the pair of electrodes 57a, 57b on the outer peripheral wall 52. Furthermore, the terminal 58 may be provided on a part of the pair of electrodes 57a, 57b on the partition wall 55, or may be provided so as to cover some of the cells 54. The thickness of the terminal 58 is not particularly limited, but is, for example, 0.01 to 10 mm, typically 0.05 to 5 mm.

[0059] The method of connecting the terminal 58 and the pair of electrodes 57a, 57b is not particularly limited as long as they are electrically connected, and they can be connected by, for example, diffusion bonding, a mechanical pressure mechanism, welding, or the like.

[0060] The dehumidifying layer 56 contains an adsorbent capable of adsorbing water vapor, and therefore has the function of adsorbing water vapor. The dehumidifying layer 56 can be provided on the surface of the partition wall 55 (in the case of the outermost cell 54, the partition wall 55 and the outer peripheral wall 52 which define the outermost cell 54). By providing the dehumidifying layer 56 in this manner, the dehumidifying layer 56 can be easily heated during regeneration, so that the desired function of the dehumidifying layer 56 can be regenerated.

[0061] The adsorbent contained in the dehumidifying layer 56 is preferably capable of absorbing moisture at an absolute humidity of 4 g / kg (DA) or less on the psychrometric chart under atmospheric pressure. This absolute humidity means the amount of water vapor [g] per unit mass [kg (DA)] of dry air. If the adsorbent has such characteristics, it can effectively dehumidify the air inside the refrigerator 10. Examples of the adsorbent include, but are not limited to, aluminosilicate, silica gel, silica, graphene oxide, polymer adsorbent, polystyrene sulfonic acid, and metal organic framework (MOF). These may be used alone or in combination of two or more.

[0062] As the aluminosilicate, it is preferable to use AFI-type, CHA-type or BEA-type zeolite, or a porous clay mineral such as allophane, imogolite, etc. Furthermore, it is more preferable that the aluminosilicate is amorphous.

[0063] As the silica gel, it is preferable to use type A silica gel. The polymer adsorbent is preferably one having a polyacrylic acid polymer chain, for example, sodium polyacrylate. The metal organic framework is a crystalline hybrid material containing metal ions and organic molecules (organic ligands). The metal ions are preferably hydrophilic metal ions (e.g., aluminum ions).

[0064] The adsorbent contained in the dehumidifying layer 56 is preferably capable of adsorbing odorous components in addition to water vapor. If it has such a function, not only the humidity in the refrigerator 10 but also odors can be removed. Examples of adsorbents capable of adsorbing odorous components include zeolite, silica gel, activated carbon, alumina, silica, low-crystalline clay, and amorphous aluminum silicate complexes. The type of adsorbent may be appropriately selected depending on the type of components to be removed. The adsorbent may be used alone or in combination of two or more types. Specific examples of odorous components include ammonia, acetic acid, isovaleric acid, nonenal, formaldehyde, toluene, xylene, paradichlorobenzene, ethylbenzene, styrene, chlorpyrifos, di-n-butyl phthalate, tetradecane, di-2-ethylhexyl phthalate, diazinon, acetaldehyde, and N-methylcarbamate-2-(1-methylpropyl)phenyl.

[0065] The dehumidifying layer 56 may contain a catalyst as necessary. By containing a catalyst, it is possible to purify odorous components by promoting oxidation-reduction reactions. Examples of catalysts having such functions include metal catalysts such as Pt, Pd, and Ag, and oxide catalysts such as CeO2 and ZrO2. The catalyst may be used alone or in combination of two or more types. The catalyst may also be used in combination with the above-mentioned adsorbent.

[0066] The thickness of the dehumidifying layer 56 is not particularly limited and may be determined depending on the size of the cells 54. For example, from the viewpoint of ensuring sufficient contact with air, the thickness of the dehumidifying layer 56 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. On the other hand, from the viewpoint of preventing the dehumidifying layer 56 from peeling off from the partition walls 55 and the outer peripheral wall 52, the thickness of the dehumidifying layer 56 is preferably 400 μm or less, more preferably 380 μm or less, and even more preferably 350 μm or less.

[0067] The thickness of the dehumidifying layer 56 is measured by the following procedure. An arbitrary cross section parallel to the flow path direction of the honeycomb structure 51 is cut out, and a cross-sectional image of about 50 times is obtained using a scanning electron microscope or the like. This cross section is also set to pass through the center of gravity of the cross section perpendicular to the flow paths of the honeycomb structure 51. For each dehumidifying layer 56 visible from the cross-sectional image, the thickness is calculated by dividing the cross-sectional area by the length of the cell 54 in the flow path direction. This calculation is performed for all dehumidifying layers 56 visible from the cross-sectional image, and the overall average value is regarded as the thickness of the dehumidifying layer 56.

[0068] From the viewpoint of exhibiting a desired function in the dehumidifying device 50, the amount of the dehumidifying layer 56 is preferably 50 to 500 g / L, more preferably 100 to 400 g / L, and further preferably 150 to 350 g / L, relative to the volume of the honeycomb structure 51. The volume of the honeycomb structure 51 is a value determined by the outer dimensions of the honeycomb structure 51.

[0069] The method for producing the dehumidifying device 50 is not particularly limited and may be performed according to a known method. The method for producing the dehumidifying device 50 will be described below as an example. The method for manufacturing the honeycomb structure 51 constituting the dehumidifying device 50 includes a molding step and a firing step. In the forming step, a clay containing ceramic raw materials including BaCO3 powder, TiO2 powder, and powder of a rare earth nitrate or hydroxide is formed to produce a honeycomb formed body having a relative density of 60% or more. The ceramic raw material can be obtained by dry mixing each powder so as to obtain a desired composition. The clay can be obtained by adding a dispersion medium, a binder, a plasticizer, and a dispersant to a ceramic raw material and kneading the mixture. The clay may contain additives such as a sifter, a metal oxide, a property improver, and a conductive powder, as necessary. The blending amount of components other than the ceramic raw materials is not particularly limited as long as the blending amount is such that the relative density of the honeycomb formed body is 60% or more.

[0070] In this specification, the "relative density of the honeycomb formed body" means the ratio of the density of the honeycomb formed body to the true density of the entire ceramic raw material. Specifically, it can be calculated by the following formula. Relative density of honeycomb formed body (%) = Density of honeycomb formed body (g / cm 3 ) / True density of ceramic raw material (g / cm 3 ) x 100 The density of the honeycomb molded body can be measured by the Archimedes method using pure water as a medium. The true density of the entire ceramic raw material is calculated by multiplying the total mass (g) of each raw material by the total actual volume (cm 3 ) can be calculated by dividing it by

[0071] The dispersion medium may be water or a mixed solvent of water and an organic solvent such as alcohol, with water being particularly preferred.

[0072] Examples of the binder include organic binders such as methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. In particular, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The binder may be used alone or in combination of two or more kinds, but it is preferable that the binder does not contain an alkali metal element.

[0073] Examples of the plasticizer include polyoxyalkylene alkyl ethers, polycarboxylic acid polymers, and alkyl phosphate esters.

[0074] The dispersant may be a surfactant such as polyoxyalkylene alkyl ether, ethylene glycol, dextrin, fatty acid soap, polyalcohol, etc. The dispersant may be used alone or in combination of two or more kinds.

[0075] The honeycomb formed body can be produced by extruding a clay. In the extrusion molding, a die having a desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0076] The relative density of the honeycomb molded body obtained by extrusion molding is 60% or more, preferably 65% ​​or more. By controlling the relative density of the honeycomb molded body within this range, it is possible to densify the honeycomb molded body and reduce the electrical resistance at room temperature. The upper limit of the relative density of the honeycomb molded body is not particularly limited, but is generally 80%, preferably 75%.

[0077] The honeycomb molded body can be dried before the firing step. The drying method is not particularly limited, and for example, a conventionally known drying method such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, etc. Among these, a drying method that combines hot air drying with microwave drying or dielectric drying is preferred because it can quickly and uniformly dry the entire molded body.

[0078] The firing step involves holding the material at 1150-1250° C., then increasing the temperature to a maximum temperature of 1360-1430° C. at a rate of 20-600° C. / hour, and holding the temperature for 0.5-10 hours. By holding the honeycomb formed body at a maximum temperature of 1360 to 1430° C. for 0.5 to 10 hours, it is possible to obtain a honeycomb structure 51 containing as a main component BaTiO3-based crystal grains in which a portion of Ba has been substituted with a rare earth element. Moreover, by maintaining the temperature at 1150 to 1250° C., Ba2TiO4 crystal particles generated during the firing process are easily removed, so that the honeycomb structure 51 can be made dense. Furthermore, by setting the heating rate from 1150-1250°C to the maximum temperature of 1360-1430°C at 20-600°C / hour, 1.0-10.0 mass% of Ba6Ti 17 O 40 Crystal grains can be generated in the honeycomb structure 51 .

[0079] The holding time at 1150 to 1250° C. is not particularly limited, but is preferably 0.5 to 10 hours. By setting the holding time in this range, Ba2TiO4 crystal particles formed during the firing process can be stably and easily removed.

[0080] The firing step preferably includes holding the mixture at 900 to 950° C. for 0.5 to 5 hours during heating. Holding the mixture at 900 to 950° C. for 0.5 to 5 hours allows BaCO3 to efficiently decompose, making it easier to obtain a honeycomb structure 51 having a predetermined composition.

[0081] Before the firing step, a degreasing step may be carried out to remove the binder. The degreasing step is preferably carried out in an air atmosphere in order to completely decompose the organic components. Moreover, it is preferable that the firing step be performed in an air atmosphere from the viewpoints of controlling electrical characteristics and reducing manufacturing costs. The firing furnace used in the firing step and the degreasing step is not particularly limited, but an electric furnace, a gas furnace, or the like can be used.

[0082] A pair of electrodes 57a, 57b are formed on the honeycomb structure 51 thus obtained. The pair of electrodes 57a, 57b can be formed by a metal deposition method such as sputtering, vapor deposition, electrolytic deposition, or chemical deposition. The pair of electrodes 57a, 57b can also be formed by applying an electrode paste and then baking it. Furthermore, the pair of electrodes 57a, 57b can be formed by thermal spraying. The pair of electrodes 57a, 57b may be formed of a single layer, but may also be formed of multiple electrode layers with different compositions. A representative method for forming the pair of electrodes 57a, 57b will be described below.

[0083] First, an electrode slurry containing an electrode material, an organic binder, and a dispersion medium is prepared and applied to the first end surface 53a or the second end surface 53b of the honeycomb structure 51. The dispersion medium may be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. Excess slurry on the outer periphery of the honeycomb structure 51 is removed by blowing and wiping. Thereafter, the slurry is dried to form a pair of electrodes 57a, 57b on the first end surface 53a or the second end surface 53b of the honeycomb structure 51. Drying may be performed while heating a heater element to a temperature of, for example, about 120 to 600°C. The series of steps of coating, slurry removal, and drying may be carried out only once, but by repeating the steps a number of times, a pair of electrodes 57a, 57b having a desired thickness can be provided.

[0084] Next, terminals 58 are placed at predetermined positions of the pair of electrodes 57a, 57b, and the pair of electrodes 57a, 57b are connected to the terminals 58. The method for connecting the pair of electrodes 57a, 57b to the terminals 58 can be the method described above. The terminal 58 may be installed after the dehumidifying layer 56 described below is formed.

[0085] Next, a dehumidifying layer 56 is formed on the surfaces of the partition walls 55 and the like of the honeycomb structure 51 . The method for forming the dehumidifying layer 56 is not particularly limited, but for example, the dehumidifying layer 56 can be formed by the following process. The honeycomb structure 51 is immersed in a slurry containing a dehumidifying material, an organic binder, and a dispersion medium for a predetermined time, and excess slurry on the end face and outer periphery of the honeycomb structure 51 is removed by blowing and wiping. The dispersion medium can be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. Thereafter, the slurry is dried to form the dehumidifying layer 56 on the surface of the partition wall 55. The drying can be performed while heating the honeycomb structure 51 to a temperature of, for example, about 120 to 600°C. The series of steps of immersion, slurry removal, and drying may be carried out only once, but by repeating the steps a number of times, a dehumidifying layer 56 of a desired thickness can be provided on the surface of the partition wall 55 or the like. [Explanation of symbols]

[0086] 10. Refrigerator 11 Insulated box 12 Refrigerator 13 Freezer 14 Air duct 15,16 Air outlet 17 Return Air Path 20,21 Insulated door 30 Insulated walls 40 Cooler room 41 Cooler 42 Compressor 43 Cool air circulation fan 50 Dehumidifying Device 51 Honeycomb structure 52 Outer wall 53a 1st end face 53b 2nd end face 54 Cells 55 Bulkhead 56 Dehumidification layer 57a, 57b A pair of electrodes 58 Terminals 60 Dehumidification room 61 Internal opening and closing door 62 External opening and closing door 63 Outdoor air circulation fan

Claims

1. The storage unit includes a storage chamber, a cooler chamber in which a cooler for cooling air flowing in from the storage chamber is installed, and a cool air circulation fan for blowing the cool air cooled by the cooler into the storage chamber, A dehumidifying device is installed in at least one of the storage chamber and the cooler chamber; The dehumidifying device includes a honeycomb structure having an outer peripheral wall and partition walls arranged inside the outer peripheral wall and defining a plurality of cells that serve as flow paths extending from a first end face to a second end face, the partition walls being made of a material having PTC characteristics, and a dehumidifying layer formed on a surface of the partition walls and containing an adsorbent capable of adsorbing water vapor.

2. The refrigerator according to claim 1 , wherein the storage compartments include at least a refrigeration compartment and a freezer compartment, and the storage compartment in which the dehumidification device is installed is the freezer compartment.

3. 3. The refrigerator according to claim 1, wherein the dehumidifying device is installed in a dehumidifying compartment adjacent to at least one of the storage compartment and the cooling compartment and separated by an internal opening and closing door.

4. 4. The refrigerator according to claim 3, wherein the dehumidifying chamber is disposed on at least one of a side surface of the storage chamber and a rear surface of the cooling chamber.

5. The refrigerator according to claim 4 , wherein the dehumidifying chamber is disposed behind the cooler chamber on an upstream side of the cooler in an air flow direction.

6. 4. The refrigerator according to claim 3, wherein the dehumidifying chamber has two openings through which outside air can flow, and an external opening door is disposed at each opening.

7. The refrigerator further includes a control unit that controls the dehumidifying device, the inner opening / closing door, and the outer opening / closing door. The refrigerator according to claim 6, wherein the control unit is controlled to perform dehumidification using the dehumidifying device by opening the internal opening / closing door and closing the external opening / closing door, and to regenerate the dehumidifying device by closing the internal opening / closing door, opening the external opening / closing door, and applying a voltage to the dehumidifying device to heat it.

8. The refrigerator according to claim 7, wherein an outside air circulating fan is disposed in the dehumidifying chamber, and the control unit is configured to drive the outside air circulating fan during regeneration of the dehumidifying device.

9. The refrigerator according to claim 1 or 2, wherein the adsorbent is capable of adsorbing odorous components in addition to the water vapor.

10. 3. The refrigerator according to claim 1, wherein the adsorbent is capable of absorbing moisture at an absolute humidity of 4 g / kg (DA) or less on a psychrometric chart under atmospheric pressure.

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