JP2002062034A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator having a defrosting heater for cold storage that generates heat at a suitable heat generation rate for defrosting an R evaporator and can be reduced in mounted volume. SOLUTION: In the refrigerator having the R evaporator 30 and an F evaporator 34, the defrosting heater 52 for cold storage constituted by installing heater wires 56 to metal foil 54 is stuck to the rear surface of the inner box 14 of a cabinet 12 positioned around the R evaporator 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator having a refrigerating evaporator and a freezing evaporator.

[0002]

2. Description of the Related Art In recent refrigerators, an upper portion of a cabinet is formed as a refrigeration space, and a lower portion is formed as a freezing space. , F eva), and the switching valve alternately supplies the refrigerant to the R eva and the F eva, thereby alternately performing a refrigeration mode for cooling the refrigeration space and a refrigeration mode for cooling the refrigeration space. Proposed.

Conventionally, glass tube heaters are provided below the F and R evas to defrost the R and F evas, respectively.

[0004]

However, providing a glass tube heater below each of the R-eva and the F-eva has a problem of increasing the cost.

In addition, there is a problem that the amount of heat generated from the glass tube heater is not required when defrosting the R-eva.

Further, the glass tube heater requires a space for providing the glass tube, and has a problem that the volume in the refrigerator is reduced.

In view of the above problems, the present invention provides a refrigerator having a refrigeration defrost heater capable of generating a heat value suitable for defrosting R-eva and reducing its mounting volume. It is.

[0008]

According to a first aspect of the present invention, there is provided a refrigerator having a refrigerating evaporator and a refrigerating evaporator. A refrigerator stuck to a cabinet located around a container.

According to a second aspect of the present invention, the cabinet is
An outer box and an inner box are combined, and a heat insulating material is injected and fired into the heat insulating space between the outer box and the inner box, and the refrigeration defrost heater is attached to the heat insulating space side of the inner box. The refrigerator according to claim 1, wherein the refrigerator is attached.

According to a third aspect of the present invention, the refrigerator is configured to perform an alternate operation in which a refrigeration mode in which a refrigerant flows through a refrigeration evaporator and a refrigeration mode in which a refrigerant flows only through the refrigeration evaporator are alternately performed. The refrigerator has a switching valve for switching a flow path of the refrigerant on the refrigerant inlet side of the refrigeration evaporator and the refrigeration evaporator, and the control means of the refrigerator controls the accumulated time of the refrigeration mode for a predetermined time T.
When the refrigerant reaches the temperature, a first defrost control for defrosting the refrigeration evaporator by the refrigeration defrost heater is performed, and when a refrigerant leak occurs in the switching valve, the accumulated time of the refrigeration mode is set to a predetermined time T1. 2. The refrigerator according to claim 1, wherein when the temperature reaches (T> T1), a second defrost control for defrosting the refrigeration evaporator is performed by the refrigeration defrost heater. 3.

According to a fourth aspect of the present invention, when the detected temperature of the refrigeration defrost temperature sensor provided in the vicinity of the refrigeration evaporator is lower than a set temperature for a predetermined time, the control means may execute the second control.
The refrigerator according to claim 3, wherein defrost control is performed.

According to a fifth aspect of the present invention, when the freezing mode is terminated, the control means sets a state in which a detection temperature of a refrigeration defrost temperature sensor provided near the refrigeration evaporator is lower than a set temperature. 4. The refrigerator according to claim 3, wherein it is determined that it is a preparation stage of the second defrost control, and the second defrost control is performed when the determination is continued for a specified number of times.

[0013] In a sixth aspect of the present invention, the control means includes:
The refrigerator according to claim 5, wherein the refrigeration evaporator is defrosted by the refrigeration defrost heater during a freezing mode in a preparation stage of defrost control.

According to a seventh aspect of the present invention, the control means includes:
4. The refrigerator according to claim 3, wherein a refrigerating fan provided near the refrigerating evaporator is rotated during the defrosting control.

According to an eighth aspect of the present invention, the control means includes:
Ending the second defrost control when the temperature detected by the refrigeration defrost temperature sensor provided near the refrigeration evaporator becomes higher than the defrost end temperature RE after starting the defrost control. 4. The refrigerator according to claim 3, wherein:

According to a ninth aspect of the present invention, the control means sets the defrosting end temperature RE higher as the detection temperature of the outside temperature sensor for detecting the outside temperature of the refrigerator is lower. The refrigerator.

According to the refrigerator of the present invention, a refrigerator located on the periphery of the refrigerator evaporator is provided with a refrigerator defrost heater having a heater wire on a metal foil, whereby the refrigerator evaporator can be defrosted. Further, since the refrigeration defrost heater is in the form of a sheet, its mounting volume can be minimized.

Further, by attaching the refrigeration defrost heater to the heat insulating space side of the inner box, the refrigeration defrost heater can be completely fixed and the heat can be reliably transferred to the periphery of the refrigeration evaporator. Can tell.

If valve leakage occurs in the switching valve that switches the flow path of the refrigerant, the refrigerant always flows through the evaporator for refrigeration, and frost is formed on the evaporator and its surroundings, resulting in overcooling. As a cause, food freezing may occur.

Therefore, when valve leakage occurs in the switching valve, it is necessary to perform defrosting.

However, instead of the conventional glass tube heater,
When a refrigeration defrost heater in which a heater wire is provided on a metal foil as described above, the calorific value is reduced.

Therefore, in order to reliably remove the frost formed on the refrigeration evaporator, when refrigerant leakage occurs in the switching valve, the first defrost control, which is the defrost in the normal alternate operation, is different from the first defrost control. The second defrost control is performed.

In the second defrost control, when refrigerant leakage occurs in the switching valve, the defrost is started when a time T1 shorter than the integrated time T of the refrigeration mode integrated in the first defrost control is reached. I do.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
Explanation will be given based on FIG.

(Structure of Refrigerator 10) The structure of the refrigerator 10 of this embodiment will be described below with reference to FIGS.

FIG. 1 is a longitudinal sectional view of the refrigerator 10.

The cabinet 12 of the refrigerator 10 includes the inner box 1
4 and the outer box 16 are combined, and a heat insulating material 20 injected and foamed with urethane foam is provided in a heat insulating space 18 therebetween.
Is filled.

The cabinets 12 are arranged in the refrigerator compartment 12 from the top.
A vegetable compartment 24, an ice making compartment 26, and a freezing compartment 28 are configured.
A switching chamber (not shown) is provided beside the ice making chamber 26.

The refrigerator compartment 22 and the vegetable compartment 24 constitute a refrigerator compartment R, and the ice making compartment 26 and the freezing compartment 28 constitute a freezing compartment F.

At the back of the vegetable compartment 24, a refrigeration evaporator (hereinafter referred to as R-eva) 30 for cooling the refrigeration space R is provided, and above the refrigeration blower fan (hereinafter referred to as R-fan). Is provided. The structure in the vicinity will be described later in detail.

At the back of the ice making room 26 and the freezing room 28, a freezing evaporator (hereinafter referred to as F-eva) 34 for cooling the freezing space F is provided. In addition, this Feva 34
Above the refrigeration fan (hereinafter referred to as F fan)
36, and below the F-eva 34, a freezing defrost heater (hereinafter, referred to as an F defrost heater) 38 including a glass tube heater is provided.

A machine room 40 is provided on the bottom rear surface of the cabinet 12, and a compressor 42 is provided therein.

A control unit 76 composed of a microcomputer is built in the upper part of the back of the cabinet 10.

A refrigerator sensor (hereinafter referred to as an R sensor) 7 for measuring the temperature inside the refrigerator is provided on the back of the refrigerator compartment 22.
The freezing compartment 28 is provided with a freezing temperature sensor (hereinafter, referred to as an F sensor) 8 for measuring the temperature in the refrigerator.
0 is provided.

Above R evaporator 30, a refrigeration defrost temperature sensor (hereinafter referred to as R defrost sensor) 82 for detecting the temperature of R evaporator 30 is provided. A freezing defrost temperature sensor (referred to as an F defrost sensor) 84 for detecting the temperature of the evaporator 34 is provided.

An outside air temperature sensor 86 for detecting the outside air temperature is provided near the control section 76.

FIG. 2 is an enlarged longitudinal sectional view of the vicinity of the R-eva 30. FIG. 3 is an exploded perspective view of the R-eva 30.

As shown in FIG. 2, the vegetable room 24 and the Reva 3
A partition wall 44 for partitioning the partition wall 4 is provided.
A cooling space 46 in which the R fan 32 and the R evaporator 30 are provided is formed between the inner case 4 and the inner box 14.

At the bottom of the cooling space 46, a water reservoir 4 for draining defrost water generated from the R-eva 30 into the machine room 40 is provided.
A drain pipe 50 is provided from the bottom of the water reservoir 48 toward the machine room 40.

The structure of a refrigeration defrost heater (hereinafter, referred to as an R defrost heater) 52 which is a feature of this embodiment will be described.

The R defrost heater 52 is formed by bonding a heater wire 56 to a sheet-like aluminum foil 54 by bending the heater wire 56.
As shown in FIG. 2, the sheet-shaped R defrosting heater 52 is attached to the back side of the inner box 14 from the R-eva 34 to the water reservoir 48, that is, the heat insulating space 18 side, with a double-sided adhesive tape.

Specifically, as shown in the perspective view of FIG.
A heater wire 56 is adhered to a rectangular sheet-like aluminum foil 54, bent into an L-shaped cross section, and adhered to the back surface of the inner box 14 so as to cover the bottom surface from the back surface of the R-eva 30. In this case, the aluminum foil 5 is inserted so that the drain pipe 50 can penetrate.
A drain hole 58 is provided at the lower part of the fourth.

A cord 60 for supplying power to the heater wire 56 protrudes from the upper part of the aluminum foil 54, and this cord 6
0 is inserted into the cabinet 12 through a through hole 60 provided in the inner box 14 located above the R fan 32.

In the case of the R defrost heater 52, since the sheet-like aluminum foil 54 is stuck from the back surface of the R evaporator 30 to the bottom surface (the position of the water reservoir 48), the F defrost heater 38 is used. It is possible to heat the R-eva 30 and sufficiently defrost only by generating heat with a calorific value (for example, 12 W) smaller than the calorific value of the glass tube heater (for example, 120 W) used in the above.

Since the sheet is in the form of a sheet, the volume to be attached can be minimized, and it is only necessary to attach it to the back side of the inner box 14, and the work efficiency is improved.

On the rear surface side of the inner box 14, since the heat insulating material 20 is injected and foamed after the R defrost heater 52 is attached, the R defrost heater 52 can be securely fixed to the back surface of the inner box 14. .

Since the rear side of the R defrost heater 52 is covered with the heat insulating material 20, the generated heat is reliably transmitted to the cooling space 46 located in the front.

(Structure of refrigeration cycle) Next, the refrigerator 10
The refrigeration cycle 64 will be described with reference to FIG.

FIG. 4 shows the structure of the refrigeration cycle 64.

The condenser 6 is connected to the discharge side of the compressor 42.
6 is connected, and a three-way valve 68 as a switching valve is connected to the refrigerant outlet side of the condenser 66.

A refrigeration capillary tube 70 is connected to one refrigerant outlet of the three-way valve 68.
0 is connected.

A freezing capillary tube 72 is connected to the other refrigerant outlet of the three-way valve 68. The outlet side of the freezing capillary tube 72 and the outlet side of the R-eva 30 become one, and the F-eva 34 Connected to the entrance.

An accumulator 74 is connected to the refrigerant outlet side of the F-eva 34 and is connected to the injection side of the compressor 42 via a suction pipe.

(Configuration of Electric System of Refrigerator 10) The configuration of the electric system of the refrigerator 10 will be described below with reference to FIG.

FIG. 5 is a block diagram of the refrigerator 10.

The controller 76 is connected to the F defrost heater 38, the F fan 36, the R defrost heater 52, the R fan 32, the compressor 42, and the three-way valve 68. Further, an R sensor 78, an F sensor 80, an R defrost sensor 82, an F defrost sensor 84, and an outside air temperature sensor 86 are connected.

(Normal Control Method) The refrigerator 10 having the above configuration
Will be described.

The refrigerator 10 alternately performs a refrigeration mode for cooling the refrigerated space R and a refrigeration mode for cooling the refrigerated space F.

That is, the refrigeration space R can be cooled by switching the three-way valve 68 in FIG. Further, by switching the three-way valve 68 and allowing the refrigerant to flow only through the F-eva 34, the freezing space F can be cooled.

The switching between the refrigeration mode and the freezing mode is performed based on the temperatures in the refrigerator detected by the R sensor 78 and the F sensor 80.

When the accumulated time of the freezing mode reaches T (for example, 8.5 hours), the compressor 42 is stopped, and the R defrost heater 52 and the F defrost heater 38 cause the R evaporator 30 and the F evaporator 38 to operate. 34 and 34 respectively. Hereinafter, performing defrosting based on the accumulated time T is referred to as first defrost control.

(Control Method in Case of Leakage of Three-Way Valve 68) There is a case where dust or the like adheres to the operating portion of the three-way valve 68, the valve is not completely switched, and refrigerant leakage occurs. A control method in this case will be described with reference to FIG.

In step 1, the normal control described above is performed.

In step 2, when the refrigerating mode (referred to as F mode in the drawing) is completed in the normal alternating cooling, it is determined whether the detected temperature of the R defrost sensor 82 is -10 ° C. or less.

The reason for this operation is that in the refrigeration mode, the refrigerant should not flow at all into the R-eva 30 and the temperature of the R-eva 30 should have risen. The leaked refrigerant causes
This is because 0 has been cooled to -10 ° C or less.
If the temperature is higher than -10 ° C, it is determined that there is no refrigerant leakage, and normal control is continued. If the temperature is lower than -10 ° C, it is determined that refrigerant leakage has occurred, and the routine proceeds to step 3.

In step 3, alternate cooling is performed three times (3
Cycle), and if the R defrost sensor 82 is at −10 ° C. or lower, the process proceeds to step 4.

The reason for this operation is that it is possible to reliably determine whether valve leakage has occurred by checking three cycles.

From a different point of view of the operation of this step, it is the same as in the case where it is determined whether or not the valve leakage continues even if a predetermined time has elapsed from the time when the first valve leakage is detected.

In step 4, it is determined whether or not the confirmation after three cycles of the state in which the valve leakage has occurred is the first time. If it is the first time (third cycle), the process proceeds to step 5, and if it is the second time (sixth cycle) or more, the process proceeds to step 6.

In step 5, in order to confirm the first time (third cycle), the control unit 76 forcibly operates the three-way valve 68 to perform valve cleaning for removing dust and the like. Then, the process returns to the normal control in step 1.

In step 6, it is determined whether or not three cycles of valve leakage are confirmed for the second time. That is,
The valve cleaning is performed, the normal control is performed, and the cycle is continued for three cycles.
This step is reached if: In this step, if this check is the second time (6th cycle), the process proceeds to step 7, and if it is the third time (9th cycle), the process proceeds to step 11.

In step 7, since the confirmation is determined to be the second time, the control unit 76 determines whether the refrigerant flow path of the three-way valve 68 is fixed to the F-eva 34 or the R-eva 30. Judge. And the refrigerant is Reva 3
In the state of flowing to the 0 side, the process returns to the normal control of Step 1 and
Conversely, when the refrigerant is flowing to the fuel cell 34 side, step 8
Proceed to.

In step 8, the refrigerant is
The refrigerant is not flowing through the R-eva 32 because the refrigerant flows toward the side. Therefore, the R defrost heater 52 is energized to defrost the R evaporator 30.

This control is performed to remove residual ice before a problem such as poor cooling is reached because it is possible to determine that the R-eva 30 is in an excessively frosted state due to refrigerant leakage.

In this case, since the refrigerant is flowing through the F-evaporator 34, there is no influence such as an increase in the temperature of the freezer compartment 28.

By the way, as a control method of the R defrost heater 52 at this time, in order to suppress an increase in the temperature in the refrigerator compartment 22 and the vegetable compartment 24, the heat amount is not more than the amount of heat for performing normal defrost (for example, 5 to 8W). ).

As a modified example, the control unit 76 constantly checks the rise of the detection temperature of the R defrost sensor 82 per unit time and the detection temperature of the R sensor 78, and if the rise is more than necessary, the R The energization of the frost heater 52 may be stopped.

In step 10, the R defrost sensor 82
It is determined whether or not the detected temperature has risen above the defrost end temperature RE (for example, 5 ° C.). If it has risen, the process proceeds to step 10; otherwise, the process returns to step 8.

At step 10, it is determined that the defrosting of the R evaporator 30 has been completed, the energization of the R defrost heater 52 is terminated, and the routine returns to the normal control of step 1. Thus, abnormal frost formation on the R-eva 30 can be prevented by energization that generates a small amount of heat.

In step 11, even if the third (ninth cycle) check is performed, the temperature detected by the R defrost sensor 82 does not rise to -10 ° C. or higher, so that the R evaporator 30 and the F evaporator 34 are forcibly removed. The second defrost control for performing the frost operation is performed.

In this case, it is considered that frost formation has occurred abnormally on the R-eva 32 due to valve leakage of the three-way valve 68. However, since the structure of the R defrost heater 52 is not a glass tube heater but an aluminum foil 54 having a small calorific value and a heater wire 56, a large amount of frost may not be removed in some cases. Therefore, it is performed at a timing shorter than the timing at which the first defrost control is performed. Specifically, in the first defrost control, the defrost starts when the accumulated time T (8.5 hours) in the refrigeration mode is reached, but in the second defrost control, T1 (T1 shorter than T) is used. When it reaches (for example, 5 hours), the process proceeds to step 12, and the forced defrost is started.

In step 12, the compressor 42
Is stopped, and the defrosting of the R-eva 30 and the F-eva 34 is forcibly started by the R-defrost heater 52 and the F-defrost heater 38. Then, the process proceeds to step 13.

In step 13, the control unit 76 measures whether or not a time T2 (for example, 2 to 3 minutes) has elapsed since the start of the forced defrosting. If the time T2 has elapsed, the process proceeds to step 14.

In step 14, the R defrost heater 52 is sufficiently heated after the time T2 has elapsed, so that the R fan 32 is rotated and the warmed air is sent to the R evaporator 30. As a result, as shown in FIG. 2, sufficiently warm air is distributed and the defrosting of the R-eva 30 can be performed.

At step 15, it is determined whether or not the defrosting of the F-eva 34 has been completed before the defrosting of the R-eva 30. If it has been completed, the process proceeds to step 16; Proceed to step 17.

In step 16, since the defrosting of the F-eva 34 has been completed, the defrosting of the R-eva 30 needs to be completed earlier, so that the R fan 32 is moved from the normal rotation speed to the high-speed rotation speed. The defrosting of the REVA 30 is performed earlier.

In step 17, the R defrost sensor 82
It is determined whether or not the detected temperature is 3 ° C. or higher. If the detected temperature is 3 ° C. or higher, the process proceeds to step 18; otherwise, the process returns to step 14.

In step 18, the R defrost sensor 82
Since the detected temperature is 3 ° C. or higher, it is determined that the defrosting of the R-eva 30 is almost finished, and the rotation of the R fan 32 is stopped.
This is because when the R fan 32 is rotated, warm air is sent to the refrigerator compartment 22 and the temperature inside the refrigerator rises. Therefore, only the R fan 18 is stopped to prevent the rise in the refrigerator temperature as much as possible.

In step 19, the R defrost sensor 82
It is determined whether or not the detected temperature is equal to or higher than the defrost end temperature RE (for example, 5 ° C.). If the detected temperature has not reached 5 ° C., the process returns to step 18. If the detected temperature has reached 5 ° C., the process proceeds to step 20.

In step 20, the R defrost sensor 82
Since the detected temperature is equal to or higher than the defrost end temperature RE (for example, 5 ° C.), it is determined that the defrosting of the R-eva 30 has been completed, and the energization of the R defrost heater 52 is terminated.

As described above, even when the R defrost heater 52 is changed from a glass tube heater to a heater using an aluminum foil having a small heat generation, the timing for starting defrost (step 11).
, The frost caused by valve leakage can be more reliably removed.

Inner box 1 provided with R defrost heater 52
Even at a location farther than 4, the defrost can be reliably performed by the flow of air generated by the R fan 32.

(Modification 1) In the above control method for valve leakage, in the first (third cycle) check, the valve is cleaned, and in the second (6th cycle) check, only the R-eva 30 is defrosted. Then, although the R-eva 30 and the F-eva 34 were forcibly defrosted in the third (ninth cycle) confirmation, the present invention is not limited to this, and both may be forcibly defrosted from the first time.

The number of confirmations may be changed.

(Modification 2) Defrosting is terminated when the detection temperature of the R defrost sensor 82 becomes equal to or higher than the defrost end temperature 5 ° C. The lower the outside air temperature detected by the outside air temperature sensor 86 is,
The defrost end temperature may be increased.

[0096]

As described above, according to the refrigerator of the present invention, a defrosting heater for refrigeration, which is provided with a heater wire on a metal foil, is attached to a cabinet located around the evaporator for refrigeration, thereby ensuring defrosting. The mounting volume can be reduced.

Further, when refrigerant leakage occurs in the switching valve, the second defrost control is performed, so that the defrost of the refrigeration evaporator can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a refrigerator showing one embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of the vicinity of an R-eva.

FIG. 3 is an exploded perspective view of the vicinity of the R-eva.

FIG. 4 is a configuration diagram of a refrigeration cycle of the present embodiment.

FIG. 5 is a block diagram of a refrigerator.

FIG. 6 is a flowchart illustrating a control method when a valve leak occurs.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Refrigerator 12 Cabinet 14 Inner box 16 Outer box 18 Insulated space 20 Insulation material 30 R eva 32 R fan 34 F eva 36 F fan 52 R Defrost sensor 54 Aluminum foil 56 Heater wire 68 Three-way valve

Claims (9)

[Claims] 1. A refrigerator having an evaporator for refrigerating and an evaporator for refrigerating, wherein a defrosting heater for refrigerating having a heater wire on a metal foil is attached to a cabinet located around the evaporator for refrigerating. A refrigerator characterized by that: 2. The cabinet is a combination of an outer box and an inner box, wherein a heat insulating material is injected and fired into a heat insulating space between the outer box and the inner box. The refrigerator according to claim 1, wherein the refrigerator is attached to the heat insulating space side of the inner box. 3. The refrigerator according to claim 1, wherein the refrigerator is configured to alternately perform a refrigeration mode in which the refrigerant flows through the refrigeration evaporator and a refrigeration mode in which the refrigerant flows only through the refrigeration evaporator. A switching valve for switching a flow path of the refrigerant on an inlet side of the refrigerant of the refrigeration evaporator; a control unit of the refrigerator; A first defrost control for defrosting the refrigerating evaporator is performed. If a refrigerant leak occurs in the switching valve, the refrigerating operation is performed when a cumulative time in the freezing mode reaches a predetermined time T1 (T> T1). The refrigerator according to claim 1, wherein a second defrost control for defrosting the refrigerating evaporator is performed by a defrost heater. 4. The control means performs the second defrosting control when a detected temperature of a refrigeration defrosting temperature sensor provided near the refrigeration evaporator is lower than a set temperature for a predetermined time. The refrigerator according to claim 3, characterized in that: 5. The control means according to claim 2, wherein, when the freezing mode is terminated, when a temperature detected by a refrigeration defrosting temperature sensor provided near the refrigeration evaporator is lower than a set temperature, a second temperature is set. 4. The refrigerator according to claim 3, wherein it is determined that it is a preparation stage of the defrost control, and the second defrost control is performed when the determination is continued for a specified number of times. 5. 6. The refrigerator according to claim 5, wherein said control means defrosts said refrigerating evaporator by said refrigerating defrost heater during a refrigerating mode in a preparation stage of a second defrost control. . 7. The refrigerator according to claim 3, wherein the control means rotates a refrigeration fan provided near the refrigeration evaporator during the second defrosting control. 8. The control means starts the second defrosting control, and the temperature detected by a refrigeration defrosting temperature sensor provided near the refrigeration evaporator becomes higher than the defrosting end temperature RE. The refrigerator according to claim 3, wherein the second defrosting control is terminated at the time. 9. The refrigerator according to claim 8, wherein the control means sets the defrosting end temperature RE higher as the detection temperature of the outside air temperature sensor for detecting the outside air temperature of the refrigerator is lower.