KR20120013586A

KR20120013586A - Refrigerator with humidity controller

Info

Publication number: KR20120013586A
Application number: KR1020100075640A
Authority: KR
Inventors: 이대영
Original assignee: 한국과학기술연구원
Priority date: 2010-08-05
Filing date: 2010-08-05
Publication date: 2012-02-15
Also published as: KR101205398B1

Abstract

PURPOSE: A refrigerator having a humidity maintenance apparatus is provided to absorb moisture from cold air being flowed into an evaporator and re-supply the absorbed moisture to inside a refrigerator, thereby preventing the inside a refrigerator from overly being dry. CONSTITUTION: A refrigerator having a humidity maintenance apparatus comprises a main body(102), a compressor(124), an evaporator, a condenser, an expander, a cool air duct, an air intake duct(132), and a humidity maintenance part(140). A storage is formed in the inner part of the main body. The compressor, the evaporator, the condenser, and the expander are installed in the inner part of the main body. The cold air duct is extended between the evaporator and storage and supplies cold air from the evaporator to the storage. The intake duct is extended between the evaporator and storage. The cold air is returned from the storage to the evaporator through the intake duct. At least a part of the humidity maintenance part is exposed to the storage side. A desiccant is charged into the humidity maintenance part. The desiccant absorbs or discharges humidity according to the circumference humidity.

Description

REFRIGERATOR WITH HUMIDITY CONTROLLER}

The present invention relates to a refrigerator having a humidity maintaining apparatus, and more particularly to a refrigerator having a device for controlling the humidity in the refrigerator.

The refrigerator is a device for storing foods such as meat, fish, vegetables, fruits, and beverages in a fresh state. Generally, the refrigerator is provided in a refrigerator body including storage spaces such as a freezer compartment, a refrigerator compartment, and a vegetable compartment, and is provided inside the refrigerator body. It comprises a refrigeration cycle device for maintaining the storage spaces at a set temperature, and a door mounted on one side of the refrigerator body to open and close the storage space.

The refrigeration cycle apparatus includes a thermoelectric cooling apparatus mainly used in a small refrigerator and a steam compression cycle apparatus generally used. The steam compression cycle apparatus includes a compressor, a condenser, an expander, and an evaporator, and the cold air generated through heat exchange with the evaporator is supplied into the refrigerator through a cold air duct installed in the refrigerator body to absorb heat in the refrigerator. The process of returning to the evaporator is repeated to maintain the internal temperature of the refrigerator within a predetermined range.

At this time, the moisture contained in the air passing through the refrigerator is condensed by cooling while passing through the evaporator, and the condensed moisture is removed by forming frost on the surface of the evaporator, so that dry cold air is supplied back into the refrigerator. . Therefore, when used for a predetermined time or more, the humidity in the refrigerator is too low, which may lower the freshness of foods stored in the refrigerator, especially vegetables stored in the refrigerator compartment.

In addition, the frost formed on the surface of the evaporator increases the energy consumption by preventing heat transfer with the air, so the defrosting operation should be performed periodically or a separate defrosting device should be provided. As a result, power consumption according to the defrosting operation is increased, and the existence of a separate defrosting device leads to an increase in the unit cost of the product.

In addition, in the heat exchange process in the evaporator, since the air having a high humidity must be cooled, there is a problem in that the dehumidification load increases as compared with the case of cooling the air having a low humidity. That is, more than 30% of the total load generated by cooling corresponds to the dehumidification load, which causes energy efficiency to be lowered, and consumes energy while removing moisture necessary to maintain the food freshness.

The present invention has been made in order to overcome the disadvantages of the prior art as described above, by maintaining a humidity in the refrigerator to limit the moisture contained in the air moving to the evaporator in the refrigerator to a certain extent to maintain a humidity within a predetermined range It is a technical problem to provide a refrigerator with a device.

According to an aspect of the present invention for achieving the above technical problem, a refrigerator body having a storage space therein; A compressor, an evaporator, a condenser and an expander installed in the refrigerator body; A cold air duct extending between the evaporator and the storage space and supplying cold air to the storage space from the evaporator; An intake duct extending between said evaporator and said storage space and returning cold air from said storage space to an evaporator; And a humidity maintaining unit installed in the refrigerator main body such that the at least part is exposed to the storage space side, wherein the humidity maintaining unit is filled with a dehumidifying agent that absorbs or releases moisture according to ambient humidity. The dehumidifying agent used for an adsorption cooling apparatus and an adsorption type dehumidifier can be used. Specifically, inorganic dehumidifying materials such as silica gel and zeolite, hygroscopic salts such as LiCl and CaCl ₂ , or high hygroscopic polymer dehumidifying materials can be used.

That is, according to the aspect of the present invention, the cold air supplied into the refrigerator compartment via the evaporator is condensed with moisture contained in the cold air by the evaporator, so the humidity is relatively low, so that moisture absorption by the humidity holding unit does not occur. However, when the supplied cold air stays in the furnace for a long time, the temperature is increased compared to the initial stage, and at the same time, moisture in the oven or moisture contained in the stored food is absorbed and introduced into the evaporator by a blower fan in a state where the humidity is high. Moisture is absorbed by the humidity holding unit to reduce the dehumidification load in the evaporator, while maintaining the humidity in the high.

In particular, since the moisture contained in the dehumidifier is supplied into the furnace by evaporation when the humidity in the high humidity is low, the moisture in the dehumidifying agent may contribute to lowering the temperature in the refrigerator refrigerator due to absorption of evaporative heat as well as maintaining the humidity in the high.

In addition, since the cold air that absorbed moisture while circulating in the refrigerator during operation of the refrigeration cycle is supplied to the evaporator in a dry state while passing through the humidity maintaining part, frost is not only minimized on the surface of the evaporator but also the dehumidification load is reduced. You can do it.

Here, the humidity maintaining part may be disposed in the intake duct, and one side may be exposed to the storage space.

In addition, an intake port communicating with the intake duct may be formed in the refrigerator main body, and the humidity maintaining part may be installed at the intake port side. Of course, the humidity maintaining unit may be installed on the cold air duct side or may be installed in the storage space in the refrigerator main body.

The humidity maintaining part may include a porous structure configured to allow air to pass therethrough, and allow the dehumidifying agent to be applied to the surface of the porous structure.

According to another aspect of the invention, the refrigerator body having a storage space therein; A compressor, an evaporator, a condenser and an expander installed in the refrigerator body; A cold air duct extending between the evaporator and the storage space and supplying cold air to the storage space from the evaporator; A humidity maintenance unit installed at one side of the storage space so as to communicate with the storage space; And guide means for guiding an upward airflow raised by heat introduced from the front surface of the refrigerator to the other side of the humidity holding portion, wherein the humidity holding portion absorbs moisture from the air in the storage space, There is provided a refrigerator, characterized in that for supplying moisture to the rising air flow introduced by.

During the operation of the refrigerator, the air flows from the outside in the process of opening and closing the door, so that the front part becomes hotter than the rest. In addition, the external heat is also transferred to the interior through the interface between the door and the refrigerator main body, so that the heated air rises to the upper part of the refrigerator compartment due to the transferred heat at the front part. In the above aspect of the present invention, the elevated air stream is allowed to pass through the humidity holding unit so that moisture adsorbed to the humidity holding unit is evaporated, and the rising air stream is cooled by the heat of evaporation.

In other words, by using natural convection, not only does not need to use a separate fan, but also allows the water to be re-supplied to the inside of the high, and the temperature inside the high due to the inflow of external heat can be lowered without running a refrigeration cycle such as a compressor. do.

Here, the humidity maintaining part may be filled with a dehumidifying agent that absorbs or releases moisture according to ambient humidity, and the humidity maintaining part includes a porous structure configured to allow air to pass through, and the dehumidifying agent of the porous structure It can be applied to the surface.

Meanwhile, a valve for selectively opening and closing the rising air inlet may be installed at the rising air inlet.

According to another aspect of the invention, the refrigerator body having a storage space therein; A compressor, an evaporator, a condenser and an expander installed in the refrigerator body; A cold air duct extending between the evaporator and the storage space and supplying cold air to the storage space from the evaporator; An intake duct extending between the evaporator and the storage space and returning cold air from the storage space to the evaporator, the air inlet duct having an upward airflow inlet at a lower front side of the refrigerator body; And a humidity holding part installed at one side of the intake duct so as to communicate with the storage space, and a rising air flow flowing into the rising air inlet. The humidity holding part may be configured to receive moisture from air in the storage space. Absorption, there is provided a refrigerator, characterized in that for supplying moisture to the rising air flowing through the rising air inlet.

The refrigerator main body may include a partition wall, and may be partitioned into a plurality of storage spaces in which the inside of the refrigerator main body is disposed up and down by the partition wall.

In addition, the intake duct may be disposed in the partition wall.

The rising air inlet may be disposed between the humidity maintaining part and the front part of the refrigerator main body.

In addition, the humidity maintaining part may be filled with a dehumidifying agent that absorbs or releases moisture according to ambient humidity, and the humidity maintaining part includes a porous structure configured to allow air to pass through, and the dehumidifying agent of the porous structure It can be applied to the surface.

In addition, the porous structure may be rotatably installed with an axis parallel to the axis extending in the up and down direction of the refrigerator in the intake duct, and may further include a driving means for rotationally driving the porous structure. .

Here, a suction port for sucking cold air in the refrigerator compartment is formed at a bottom of the intake duct, and the porous structure may be disposed over the suction port and the upper portion of the rising air inlet.

In addition, the porous structure may be formed to have a circular cross section.

In addition, the intake duct may include a first partition plate extending downwardly between the intake port and the upstream air inlet, and in addition, the intake duct may extend upwardly between the intake port and the upstream air inlet. It may also include an elongated second partition plate.

According to the aspects of the present invention having the above configuration, it is possible to absorb the moisture from the cold air flowing into the evaporator and then resupply it to the inside of the refrigerator high to prevent the interior of the refrigerator high excessively dried, leading to the best state of food In addition, the humidity of the air in contact with the evaporator is lowered, thereby reducing the dehumidification load and minimizing frost on the evaporator surface.

1 is a perspective view showing a first embodiment of a refrigerator according to the present invention.
FIG. 2 is a cross-sectional view schematically showing the internal structure of the first embodiment shown in FIG.
3 is a perspective view illustrating a water retaining unit in the first embodiment shown in FIG. 1.
4 is a wet air diagram for explaining the principle of operation of the first embodiment.
5 is a cross-sectional view schematically showing the internal structure of a second embodiment of a refrigerator according to the present invention.
6 is a cross-sectional view schematically showing the internal structure of a third embodiment of a refrigerator according to the present invention.
FIG. 7 is a perspective view illustrating a water retaining unit in the embodiment illustrated in FIG. 6.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the refrigerator according to the present invention.

1 is a perspective view showing a first embodiment of a refrigerator according to the present invention. Referring to FIG. 1, the first embodiment 100 includes a refrigerator body 102 having a freezer compartment at an upper portion thereof and a refrigerating compartment at a lower portion thereof. The front surface of each of the freezer compartment and the refrigerating compartment is provided with a freezer compartment door 110 and a refrigerating compartment door 112 for opening and closing the internal space of the refrigerator.

Here, the embodiment is disclosed with respect to a refrigerator of a general type, but is not necessarily limited thereto, and the present invention may be applied to any type of refrigerator.

2 is a cross-sectional view illustrating the internal structure of the embodiment, referring to FIG. 2, the refrigerator body 102 is configured to block heat loss to the outside by installing an insulating material therein, and the freezer compartment 10 ) And partition wall 114 partitioning the refrigerating chamber 20 is installed in the center of the refrigerator main body 102. In addition, a plurality of shelves 30 are installed in the refrigerating chamber 20 to efficiently store food.

In addition, cold air outlets 104 and 106 are formed on the rear surface of the freezing chamber 10 and the rear surface 20 of the refrigerating chamber, respectively, and the cold air discharge ports are in communication with the cold air duct 130 which will be described later. In addition, inlet ports 105 and 107 are formed on the bottom surface of the freezer compartment 10 and the upper surface of the refrigerating compartment 20, respectively, and these inlet ports are formed with intake ducts 132 formed inside the partition wall 114, respectively. Communicating. Here, the partition plate 116 is provided inside the intake duct 132, and the partition plate 116 extends in parallel with the partition wall 114 to partition the inside of the intake duct 132 up and down. Doing.

On the other hand, a machine chamber is formed on one side of the bottom surface of the main body 102, and a condenser 122 and a compressor 124 as part of a refrigeration cycle apparatus are disposed inside the machine chamber. In addition, an evaporator 120 is installed inside the intake duct 130 of the main body 102, and an expander (not shown) is installed between the evaporator and the condenser to form a refrigeration cycle device. In this case, a blower fan 126 is installed on the rear surface of the evaporator 120 to allow the internal air of the freezing chamber 10 and the refrigerating chamber 20 to circulate.

Therefore, when the blower fan 126 rotates, air in the freezer compartment and the refrigerating compartment is sucked through the intake vents 105 and 107 to flow inside the intake duct 132, thereby passing through the evaporator 120. It cools down. The cooled air flows through the cold air duct 130 and is re-supplied into the refrigerating chamber and the freezing chamber through the discharge holes 104 and 106 to maintain the inside of the storage space at the set temperature.

On the other hand, the moisture holding unit 140 is installed inside the intake duct 132. Specifically, the moisture holding unit 140 is installed in the refrigerating chamber side inlet 107, and the air flowing into the evaporator 120 is configured to pass through the moisture holding unit 140.

3 is a perspective view of the moisture holding unit 140, wherein the moisture holding unit 140 includes a frame 142 having a rectangular shape and a porous structure 144 coupled to the inside of the frame 142. have. The porous structure 144 is configured to have a plurality of through holes 146. In the example shown in FIG. 3, the through holes 146 have a hexagonal shape, but are not necessarily limited thereto. It may have a form.

The dehumidifier is applied to the inner wall of the through hole 146. The dehumidifying agent means a material having a property of absorbing or discharging moisture according to humidity conditions, and generally refers to a material used for an adsorption cooling device or an adsorption dehumidifying device. As the dehumidifying agent, inorganic dehumidifying materials such as silica gel and zeolite, hygroscopic salts such as LiCl and CaCl ₂ , or high hygroscopic polymer dehumidifying materials can be used. The dehumidifying agent absorbs the moisture contained in the air when the moisture contained in the dehumidifying agent is lower than the humidity in the refrigerating chamber, and in the case of the dehumidifying agent, the dehumidifying agent can be resupplyed into the refrigerating chamber while the absorbed moisture is evaporated.

Therefore, when the compressor and the blower fan are processed, that is, when the internal temperature of the refrigerating compartment is higher than or equal to the set temperature, the cool air is supplied into the refrigerating compartment by the cooling cycle apparatus. It will continue until it is reached. Therefore, the cold air passing through the water holding unit 140 is absorbed a part of the water by the dehumidifying agent applied to the inside of the water holding unit 140, so that the water holding unit 140 in a state where the absolute humidity is lowered. Will pass. That is, in FIG. 4, point 1 is in a state immediately before a cooling cycle is operated, and point 2 is in a state of passing through the water holding part 140. The process of absorbing moisture from the water holding unit 140 is a heat generation process, so that a slight temperature rise occurs when air passes through the water holding unit 140.

Cool air having such a low absolute humidity is sequentially moved to the state of the points 3 and 4 while being cooled by heat exchange while contacting the surface of the evaporator 120, the specific gravity of the dehumidification load is lower than when the absolute humidity is high As a result, the energy consumption can be reduced. In other words, if cooling is performed without removing moisture, point 4 is reached along the curve at point 1, which means that cooling is performed while saturated air is saturated, which increases the dehumidification load. According to the above embodiment, since the dehumidification load can be substantially reduced, the amount of energy consumed for cooling can be reduced.

Thereafter, the cold air passing through the evaporator 120 passes through the cold air duct and is discharged into the refrigerator compartment in the state of point 5 and mixed with the air existing in the inside to reach the state of point 6. However, the state at point 6 is too dry to store food.

On the other hand, the absorption of the water is made continuously during the operation of the refrigeration cycle device, the absorption of water is also stopped when the refrigeration cycle device is stopped by reaching the set temperature. Thereafter, when the humidity in the refrigerator is lowered, moisture adsorbed on the surface of the moisture holding unit 140 is evaporated, and water is re-supplied into the refrigerator. The water supplied in this way helps to maintain the freshness of foods stored in the oven, especially vegetables and fruits, so that foods can be kept in good condition for a longer period of time.

In addition, as moisture evaporates, it absorbs as much heat as the heat of evaporation from the surrounding air, thus helping to lower the temperature in the furnace (the temperature at point 7 is lower than the temperature at point 6). That is, according to the first embodiment, the cooling efficiency can be improved while maintaining the moisture in the refrigerator compartment without supplying additional energy.

The first embodiment may be modified in various forms. As an example, the moisture holding part does not necessarily need to be installed inside the suction duct but may be installed at any place where the moisture holding part may come into contact with the cold air supplied from the cold air duct. For example, the moisture holding part may be located inside the refrigerator, or may be located inside the cold air duct, and in any case, it is sufficient to be able to supply water into the refrigerator while being in contact with the cold.

FIG. 5 is a cross-sectional view showing a second embodiment of the refrigerator according to the present invention. In the description of the second embodiment, the same components as those of the first embodiment will be denoted by the same reference numerals and may be repeated. Is omitted.

Referring to FIG. 5, the suction port 107 of the intake duct 132 is moved to the rear side of the refrigerator rather than the moisture holding unit 140. In addition, an upward airflow inlet 108 is additionally formed between the water holding unit 140 and the refrigerating chamber door 112. A valve 109 is formed at the upstream air inlet 108 to open and close the upstream air inlet 108, wherein the valve 109 is opened according to a temperature around the upstream air inlet 108. It is configured to be operable by a temperature sensing means and an actuator, not shown, to be closed. Therefore, when the compressor is operated due to the high temperature in the refrigerator compartment, the valve 109 closes the upward airflow inlet 108, and when the compressor is stopped due to the low temperature, the valve 109 closes the upward airflow inlet 108. Open.

Now, the operation of the second embodiment will be described. In the second embodiment, when the cold air is supplied as in the first embodiment, water absorption is performed in the water holding unit 140. In addition, the release of water is also made the same.

On the other hand, due to the amount of heat introduced from the outside through the opening of the refrigerating compartment door 112 or the gap between the door 112 and the main body 102, the portion adjacent to the door 112 is relatively hot compared to the portion that is not. Will increase. When the temperature of the air is increased in this way, an upward airflow is generated due to the density difference, and the air flow to the upward airflow inlet 108 is generated.

Therefore, relatively high temperature air is introduced into the intake duct 132 through the rising air inlet 108 and then passes through the water holding part 140. At this time, the rising air flow is relatively high temperature to evaporate the moisture adsorbed on the dehumidifying agent applied to the inside of the water holding unit 140, the temperature is lowered due to the heat of evaporation. As a result, the rising air passing through the water holding unit 140 is changed into a low temperature and high humidity state in a high temperature dry state and is resupplied into the refrigerator. In particular, since the cooled rising air flows relatively dense, it forms a falling air flow, and thus recirculation of water may be continuously performed while the air is naturally circulated without a separate fan.

In addition, since the heat introduced from the outside can be cooled through the dehumidifying agent without operating a separate cooling cycle, it helps to maintain the temperature in the refrigerator.

The second embodiment may be modified in any form. Instead of separately forming the inlet 107, the water retaining part may be disposed in the inlet 107 as in the first embodiment. It is also possible to omit the valve and to enable continuous operation, an example of which is shown in FIG. 6. In the description of the third embodiment shown in FIG. 6, the same or similar components as those of the first and second embodiments will be denoted by the same reference numerals and redundant descriptions thereof will be omitted.

Referring to FIG. 6, the moisture holding part 240 is rotatably mounted in the intake duct 132 of the third embodiment. As shown in FIG. 7, the moisture holding part 240 includes a frame 242 having a circular cross section, a hub 246 positioned at the center of the frame 242, and the frame 242 and a hub 246. It includes a plurality of spokes 248 extending between. In addition, the porous structure 244 as shown in the first embodiment is inserted into the frame 242.

6, the water holding part 240 is installed to be rotatable by an actuator (not shown) such as a motor in the intake duct 132, and is provided at an upper and a lower part of the water holding part 240. Partition plates 117 and 118 are respectively provided to guide the flow of air. The partition plate 117 located at the upper portion of the moisture holding part 240 is configured to block the rising air from moving to the evaporator through the intake duct 132, and the partition plate 118 located at the lower portion thereof is It is configured not to mix the flow of air in the water holding unit 240.

In addition, the two partition plates 117 and 118 are disposed to traverse the center of the water holding part 240, that is, the upper and lower portions of the hub 246, respectively, so that the air around the water holding part 240 is separated. It is configured to split the flow. In addition, the flow guide 119 is also installed in the outer peripheral part of the door side of the moisture holding part 240.

The operation of the third embodiment will now be described.

The moisture holding unit 240 continues to rotate while the refrigeration cycle device is operating. Therefore, the side of the moisture absorbed from the cold air passing through the water holding unit 240 is moved to the door side by the rotation and comes in contact with the rising air flow to supply the water again. Thereafter, the water retaining unit 240 where the water is evaporated and regenerated is moved back to the cold air intake side to absorb water, and this process is repeated continuously.

At this time, the partition plate 117 prevents the rising air flows into the evaporator along the intake duct, and the partition plate 118 and the flow guide 119 have the cold air passing through the water holding unit 240 immediately. It serves to prevent the inflow to the air intake.

Therefore, in the third embodiment, the absorption and resupply of water and the cooling of the rising air can be continuously performed while the compressor is running, and thus can be usefully applied to a large refrigeration facility in which the compressor is always operated.

Claims

A refrigerator body having a storage space therein;
A compressor, an evaporator, a condenser and an expander installed in the refrigerator body;
A cold air duct extending between the evaporator and the storage space and supplying cold air to the storage space from the evaporator;
An intake duct extending between said evaporator and said storage space and returning cold air from said storage space to an evaporator; And
And a humidity maintaining unit installed in the refrigerator main body such that the at least part is exposed to the storage space.
The humidity maintaining unit is a refrigerator, characterized in that filled with a dehumidifying agent that absorbs or releases moisture in accordance with ambient humidity.

The method of claim 1,
The humidity maintaining unit is disposed in the intake duct, one side of the refrigerator characterized in that exposed to the storage space.

The method of claim 2,
An inlet is formed in the refrigerator main body to communicate with the intake duct,
The humidity holding unit is a refrigerator, characterized in that installed on the intake port side.

The method of claim 1,
The humidity maintaining unit includes a porous structure configured to allow air to pass through, and the dehumidifier is applied to the surface of the porous structure.

The method of claim 1,
And the humidity maintaining unit is disposed in the storage space.

A refrigerator body having a storage space therein;
A compressor, an evaporator, a condenser and an expander installed in the refrigerator body;
A cold air duct extending between the evaporator and the storage space and supplying cold air to the storage space from the evaporator;
A humidity maintenance unit installed at one side of the storage space so as to communicate with the storage space; And
It includes a guide means for guiding the rising air flows by the heat introduced from the front of the refrigerator to the other side of the humidity maintaining portion,
And the humidity maintaining part absorbs moisture from air in the storage space and supplies moisture to an upward air flow introduced by the guide means.

The method of claim 6,
The inside of the humidity holding unit is a refrigerator characterized in that the dehumidifying agent is absorbed or released according to the ambient humidity.

The method of claim 7, wherein
The humidity maintaining unit includes a porous structure configured to allow air to pass through, and the dehumidifier is applied to the surface of the porous structure.

The method of claim 6,
And a valve for selectively opening and closing the upward airflow inlet at the upward airflow inlet.

A refrigerator body having a storage space therein;
A compressor, an evaporator, a condenser and an expander installed in the refrigerator body;
A cold air duct extending between the evaporator and the storage space and supplying cold air to the storage space from the evaporator;
An intake duct extending between the evaporator and the storage space and returning cold air from the storage space to the evaporator, the air inlet duct having an upward airflow inlet at a lower front side of the refrigerator body; And
And a humidity maintaining part installed at one side of the intake duct so as to communicate with the storage space, and having the rising air flowed into the rising air inlet.
And the humidity maintaining part absorbs moisture from the air in the storage space and supplies moisture to the rising air flowing through the rising air inlet.

The method of claim 10,
The refrigerator main body includes a partition and is divided into a plurality of storage spaces in which the inside of the refrigerator main body is disposed by the partition.

The method of claim 11,
And the intake duct is arranged inside the partition wall.

The method of claim 12,
The rising air inlet is a refrigerator, characterized in that disposed between the humidity maintaining portion and the front portion of the refrigerator main body.

The method of claim 13,
The inside of the humidity holding unit is a refrigerator characterized in that the dehumidifying agent is absorbed or released according to the ambient humidity.

The method of claim 14,
The humidity maintaining unit includes a porous structure configured to allow air to pass through, and the dehumidifier is applied to the surface of the porous structure.

16. The method of claim 15,
The porous structure is a refrigerator, characterized in that rotatably installed in the intake duct with an axis parallel to the axis extending in the vertical direction of the refrigerator as a rotation axis.

The method of claim 16,
The bottom surface of the intake duct is formed with a suction port for sucking the cold air in the refrigerator,
The porous structure is characterized in that the refrigerator is disposed over the upper portion of the inlet and the air stream inlet.

The method of claim 17,
And the porous structure is formed to have a circular cross section.

The method of claim 17,
And the intake duct comprises a first partition plate extending downward between the intake port and the upward airflow inlet.

20. The method of claim 19,
And the intake duct comprises a second partition plate extending between the intake port and the upward airflow inlet to the upper side of the refrigerator.