JPH09329386A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of leakage of a refrigerant to the interior of a refrigerator by a method wherein a vaporizer is arranged in an inner box and a connection part between the vaporizer and a piping is arranged in a heat insulation material. SOLUTION: A refrigerator comprises a heat insulation box body formed such that a heat insulation material 4 is arranged between outer and inner boxes 2 and 3, a refrigerating cycle which is formed such that constituting elements, such as a compressor 9, a condenser 10, a pressure reducing device, and a vaporizer 13, are connected together through a piping, and which is sealed with a mixture refrigerant containing a combustible refrigerant or a combustible refrigerant consisting of a single component. The vaporizer 13 is arranged in the inner box 3 and a connection part between the vaporizer 13 and pippings 17, 18 is arranged in a heat insulation material 4. A substance to from independent air bubbles by foaming and fill a foaming space with the air bubbles is used as the heat insulation material 4. By arranging the vaporizer in the inner box and forming a connection part between the vaporizer and a piping in a heat insulation material, the connection part wherein a possibility of leakage of a refrigerant occurring is high is eliminated from the interior of a refrigerator and a possibility of leakage of a refrigerant occurring is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator using a flammable refrigerant.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of protecting the ozone layer, the use of a refrigerant containing a chlorine atom such as the refrigerant CFC (chlorofluorocarbon) -12 or HCFC (hydrochlorofluorocarbon) -22 used in a refrigeration cycle is restricted. , It is necessary to switch to a refrigerant that does not have ozone depleting ability. HFC (hydrofluorocarbon) is considered as a refrigerant without ozone depleting ability. For example, it is described on pages 54 to 56 of the ozone layer depleting substance use reduction manual (issued in July 1991) issued by the Council for the Protection of Ozone Layers. As described above, as an alternative refrigerant for a refrigerator in which CFC-12 has been used, H 2 having a close boiling point is used.
FC-134a is listed as the first candidate.

[0003]

However, with the above-mentioned prior art, although the purpose of protecting the ozone layer can be achieved, from the viewpoint of preventing global warming, the efficiency of the refrigeration cycle as a refrigerant is high, and A refrigerant with a small coefficient is desired.
As a refrigerant having no ozone depleting ability and having a very small global warming potential, an HC (hydrocarbon) refrigerant can be considered. In particular, the refrigerant in which propane and isobutane are mixed is CF
The boiling point is close to C-12, and propane is 40 to 60% by mass.
Refrigeration capacity is also close to CFC-12 with the mixed refrigerant of No. However, the HC-based refrigerant has flammability, and particularly when it is used as a refrigerant for a refrigerator, if the refrigerant leaks into the refrigerator having a small volume, even a small amount of leakage will cause an explosion limit. For this reason, it is necessary to prevent the refrigerant from leaking into the refrigerator and to ensure safety.

An object of the present invention is to prevent the risk of explosion in a refrigerator using a flammable refrigerant by reducing the refrigerant leakage into the inside of the refrigerator, which is a closed space.

[0005]

The above object is to provide a heat insulating box body in which a heat insulating material is arranged between an outer box and an inner box, and components of a compressor, a condenser, a decompression device, and an evaporator by piping. In a refrigerator connected with a refrigeration cycle in which a flammable refrigerant consisting of a mixed refrigerant or a single component containing a flammable refrigerant is connected, the evaporator is installed inside an inner box, and the evaporator and piping are connected. This is achieved by providing the connection part of the inside of the heat insulating material.

By installing the evaporator inside the inner box and providing the connecting portion between the evaporator and the pipe inside the heat insulating material, the pipe connecting portion which is likely to cause the refrigerant leakage disappears from the inside of the refrigerator, and the refrigerant leakage can occur. The sex can be reduced.

The above-mentioned object is also to combust flammability by connecting a heat insulating box having a heat insulating material arranged between an outer box and an inner box to constituent elements of a compressor, a condenser, a pressure reducing device and an evaporator by piping. In a refrigerator having a refrigeration cycle in which a mixed refrigerant containing refrigerant or a flammable refrigerant consisting of a single component is installed, a refrigerant leakage detector is provided around the evaporator and an exhaust hole communicating the inside and outside of the refrigerator. It is also achieved by providing a blower for forcibly discharging the air inside the refrigerator to the outside through the discharge hole when the detector detects a refrigerant leak. The evaporator is preferably installed inside the inner box.

A refrigerant leak detector is provided around the evaporator, and an exhaust hole is provided for communicating the inside and outside of the refrigerator. When the detector detects a refrigerant leak, the air inside the refrigerator is forcibly discharged to the outside through the exhaust hole. By providing such a blower, it is possible to reduce the amount of accumulated refrigerant in the refrigerator even if refrigerant leaks.

In any case, it is desirable that the refrigerant pipe constituting the evaporator is a single pipe without seams.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a refrigerator according to a first embodiment of the present invention, and FIG. 2 is a detailed diagram of an evaporator according to the first embodiment. The illustrated refrigerator includes a refrigerator body 1 and
It is composed of a device forming a refrigeration cycle for cooling the inside of the refrigerator body.

The refrigerator main body 1 is formed by an outer box 2, an inner box 3 installed inside the outer box 2, and a heat insulating material 4 arranged between the outer box 2 and the inner box 3, and a partition wall. A heat-insulating box body which is divided into a freezing compartment 5 and a refrigerating compartment 6 by 39, and a freezing compartment door 7 and a refrigerating compartment door 8 which can be opened and closed respectively installed in the freezing compartment 5 and the refrigerating compartment 6
It consists of and. As the heat insulating material 4, a material that forms closed cells by foaming and fills the foaming space is used. The space between the outer case 2 and the inner case 3 is sealed by the outer case 2 and the inner case 3 and a heat insulating material 4 composed of closed cells filled between them.

The refrigeration cycle for cooling the inside of the refrigerator body 1 includes a compressor 9, a condenser 10 connected to the compressor 9 by a discharge pipe 16, an on-off valve 11 in the condenser 10 and a capillary as a pressure reducing device. An evaporator 13 connected by a liquid pipe 17 that interposes a tube 12, a gas pipe 18 that connects the outlet side of the evaporator 13 to a check valve 15 via a receiver tank 14, and an outlet of the check valve 15. The suction pipe 19 is connected to the inlet side of the compressor 9, and a flammable refrigerant (for example, a mixed refrigerant of propane and isobutane) flows in the piping. Each device is connected to each other by piping and between the pipes by brazing, and each connection portion is arranged inside the heat insulating material 4. Further, the capillary tube 12 and the gas pipe 18 are arranged so as to exchange heat with each other. As shown in FIG. 2, the evaporator 13 installed on the rear wall of the freezer compartment 5 in the inner box 3 is formed by bending a single pipe (refrigerant pipe) 41 provided with independent fins 42 for expanding the heat transfer area. A defrost heater 50 having no connecting portion and having a defrost heater temperature detector 51 attached is provided between the fins 42. Further, the compressor 9 and the condenser 10 are arranged in the lower part of the refrigerator and below the outer box 2.

An electric box 20 is provided above the refrigerator 1,
Inside the electric component box 20, a refrigerant leakage detector 21 inside the refrigerator placed near the defrosting heater 50, an external refrigerant leakage detector 22 placed below the refrigerator (near the compressor 9 below the outer box 2),
An evaporator temperature detector 23 arranged in contact with the evaporator 13;
Freezing room temperature detector 24 arranged in freezing room 5, refrigerating room temperature detector 25 arranged in refrigerating room 6, defrost heater 5
A defrosting heater temperature detector 51, a freezer compartment door opening / closing detector 60 and a refrigerating compartment door opening / closing detector 61, which are arranged in contact with 0, and a controller 26 that receives detection values from the detector 26, and a compressor from a signal from the controller 26. A compressor drive device 27 for driving the motor 9, and a defrost heater control device 28 for energizing the defrost heater 50 are closed.

The freezer compartment door opening / closing detector 60 and the refrigerating compartment door opening / closing detector 61 are installed in the refrigerator main body 1 and serve as an explosion-proof structure, which is a switch whose periphery is sealed by an elastic body. When is closed, the switch contacts the elastic body to detect opening and closing. On the front surface of the freezer compartment door 7, there is installed a refrigerant leak indicator 29 which indicates the refrigerant leak when the refrigerant leak detector 21 and the external refrigerant leak detector 22 detect the refrigerant leak. A fan 31 is installed above the evaporator 13 in the freezer compartment 5, and the fan 31 is driven by a fan drive device 30 placed outside the heat insulating box. The fan driving device 30 is controlled by a signal from the controller 26.

The rear wall of the freezer compartment 5 and the rear wall of the refrigerating compartment 6 are formed with an air passage 32 separated into an air intake side and an outlet side, and a freezer outlet 35 is provided in the air passage on the outlet side.
Refrigerating room outlets 36 are arranged respectively. The air passage 32 on the air intake side is extended to the inside of the partition wall 39 that separates the freezing chamber 5 and the refrigerating chamber 6, and a freezing opening is formed on the upper surface and the lower surface of the front end portion (end portion near the door) of the partition wall 39. A room suction port 33 and a refrigerating room suction port 34 are provided. That is, the place where the fan 31 is installed forms a boundary between the air passage on the suction side and the air passage on the discharge side, and the evaporator 13 is arranged in the air passage on the suction side. The fan 31 has a freezer inlet 3
3. Air passage 32 on the suction side from the refrigerating room suction port 34
Through the freezer compartment 35, the freezer compartment 35, and the freezer compartment 35 through the air passage 32 on the discharge side.
It is spitting again into the refrigerator compartment 6. The air passage 32 on the discharge side blows out the air driven by the fan 31 from the freezing compartment outlet 35 or the refrigeration compartment outlet 36 by operating a damper (not shown) with a signal from the controller 26. It is possible to select whether to blow out or to blow out from both.

A water receiving tray 37 for defrosting is arranged in the air passage 32 on the suction side below the evaporator 13, and the water received by the water receiving tray 37 passes through a drain pipe 38 and is provided above the compressor 9. It is adapted to be sent to the evaporating dish 40.
That is, the internal space of the water receiving tray 37 inside the refrigerator and the internal space of the evaporation tray 40 outside the refrigerator are communicated with the drain pipe 38 as a communication hole.

The operation of the refrigerator configured as described above will be described. The freezer compartment door open / closed detector 60 and the refrigerator compartment door open / closed detector 61 detect that the freezer compartment door 7 and the refrigerator compartment door 8 are closed, and the temperature detected by the freezer compartment temperature detector 24 is When the temperature is equal to or higher than the preset temperature of 1 or the temperature detected by the refrigerator temperature detector 25 is equal to or higher than the second preset temperature, the controller 26 opens the opening / closing valve 11, and the compressor driving device 27 and the fan driving device 30. The compressor 9 and the fan 31 are driven via the. The refrigerant gas compressed to a high temperature and high pressure by the compressor 9 is sent to the condenser 10 through the discharge pipe 16 whose connection portion is arranged inside the heat insulating material 4. The refrigerant gas that has entered the condenser 10 radiates heat to the surrounding air and becomes liquid refrigerant,
The on-off valve 1 passes through the liquid pipe 17 arranged inside the heat insulating material 4.
After passing through 1, the pressure is reduced in the capillary tube 12 while exchanging heat with the refrigerant in the gas pipe 18 and sent to the evaporator 13.
The liquid refrigerant flowing in the refrigerant pipe 41 of the evaporator 13 is the fan 3
1 absorbs heat from the air sent by 1 through the fins 42,
Evaporate. Then, the refrigerant separates the liquid refrigerant that has not evaporated in the receiver tank 14, and only the gas refrigerant passes through the gas pipe 18, returns through the check valve 15 and the suction pipe 19 to the compressor 9, and constitutes a refrigeration cycle. .

In the air cooled by the evaporator 13, the temperature detected by the freezer compartment temperature detector 24 or the refrigerating compartment temperature detector 25 is higher than the respective set temperature, for example, the freezer compartment temperature detector 24 detects the temperature. When the temperature is equal to or higher than the first set temperature, the fan 31 blows the air from the freezer compartment outlet 35 into the freezer compartment 5. When the temperature detected by the refrigerator compartment temperature detector 25 is equal to or higher than the second set temperature, the air cooled from the refrigerator compartment outlet 36 is blown out to the refrigerator compartment 6 by switching the damper (not shown) to cool the inside. . Here, when the temperature detected by the freezing room temperature detector 24 or the refrigerator room temperature detector 25 becomes equal to or lower than the third set temperature or the fourth set temperature, respectively, the fan 31 is stopped by the controller 26 and the on-off valve 11 is turned off. Closes. The compressor 9 is stopped after the operation is further continued until the first set time elapses after the opening / closing valve 11 is closed. When the operation of the compressor 9 is continued after the opening / closing valve 11 is closed, the pressure in the evaporator 13 is reduced and the accumulated liquid refrigerant is evaporated by the time the first set time elapses. After being sent from the compressor 9 to the condenser 10, it is condensed and stays in the condenser 10 as a liquid refrigerant.
Even if the compressor is stopped thereafter, the refrigerant passage (the liquid pipe 17 and the gas pipe 18) is blocked by the on-off valve 11 and the check valve 15, so that the refrigerant accumulated in the condenser 10 remains in the evaporator 13.
Never flow to.

When the cumulative operating time of the compressor 9 exceeds the third set time, the defrosting operation is performed. When the cumulative operating time exceeds the third set time and the internal refrigerant leakage detector 21 detects that there is no refrigerant leakage, the controller 26 energizes the defrost heater 50 and the defrost heater 50 causes the evaporator. 13 is heated. By this heating, the frost adhering to the fins 42 is melted and becomes water, which accumulates in the water receiving tray 37.
Is sent to the evaporation dish 40 through the drain pipe 38. Evaporating dish 4
The water retained at 0 is evaporated by the heat of the compressor 9. When the temperature detected by the evaporator temperature detector 23 becomes equal to or higher than the fifth set temperature, it is determined that the defrosting has ended, and the normal operation is resumed. At this time, when the defrost heater 50 becomes high in temperature due to some abnormality and the temperature detected by the defrost heater temperature detector 51 reaches the sixth set temperature set below the propane ignition temperature of 432 ° C. The power supply to the defrost heater is cut off regardless of the temperature detected by the evaporator temperature detector 23.

When the internal refrigerant leakage detector 21 and the external refrigerant leakage detector 22 detect the refrigerant leakage, the controller 26 closes the on-off valve 11 regardless of whether the compressor 9 is operating or stopped. After that, the compressor 9 operates for the first set time, and the refrigerant leak indicator 29 indicates that a refrigerant leak has occurred. After the on-off valve 11 is closed, the compressor 9 is operated for the first set time to collect the refrigerant in the system in the condenser 10, and then the freezer compartment temperature detector 24 and the refrigeration compartment temperature detector 25 detect the temperature. Regardless of the temperature, power to all electrical products is stopped.

As described above, in this embodiment, the refrigeration cycle inside the refrigerator (inside the inner box) is only the evaporator 13 constituted by one heat transfer pipe (refrigerant pipe 41), and the refrigerant to the inside of the refrigerator is cooled. The risk of leakage is extremely low. Further, even if a refrigerant leaks from the connecting portion between the pipe and the device due to some accident, the refrigerant leaks into the sealed heat insulating material 4, so that the amount leaking into the refrigerator is small. Further, when the refrigerator operation is stopped or when a refrigerant leak is detected during operation, the refrigerant in the refrigeration cycle is recovered from the check valve 15 to the on-off valve 11 including the condenser 10, so that the refrigerator is Even if refrigerant leaks inside due to pipe damage or the like, there is almost no refrigerant leak into the refrigerator. Further, even if the refrigerant leaks into the refrigerator for some reason, the refrigerant leakage detector 21 detects the refrigerant leakage and collects it on the condenser side, so the amount leaking into the refrigerator is small. .

Further, the freezer compartment door opening / closing detector 60 and the refrigerating compartment door opening / closing detector 61 are explosion-proof structures which are switches with their surroundings sealed by an elastic body, and the fan drive device 30 is installed outside the refrigerator. Even if a refrigerant leak occurs, the defrosting heater 50 is a dual safety device that is energized only when it does not detect a refrigerant leak, and is not energized when the refrigerant ignition temperature or higher is reached. There is no ignition source, the risk of explosion can be avoided, and when a refrigerant leak is detected, the user is alerted by displaying the refrigerant leak on the refrigerator surface.

In this embodiment, the defrosting heater temperature detector 51 is used to detect an abnormality in the defrosting heater 50, and the energization is stopped when the temperature exceeds the set temperature. Then, the resistance increases sharply and the same effect can be obtained by using a PTC heater in which no current flows. The open / close detectors for the freezer compartment door and the refrigerator compartment door may be explosion-proof type detectors.

A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a configuration diagram of a refrigerator according to a second embodiment of the present invention, and FIG. 4 is a time chart of control when a refrigerant leak is detected. The present embodiment is different from the refrigerator shown in FIG. 1 in that a damper 43 for blocking an air passage on the suction side through which air sucked from the freezer compartment suction port 33 and the refrigeration compartment suction port 34 is provided, and the fan 31 is The point is that it can rotate in the reverse direction. The operation of the damper 43 is controlled by the controller 26. Other configurations are the same as those in FIG. 1, and the same reference numerals represent the same parts.

The operation of the refrigerator configured as above will be described. The cooling operation of the refrigerator is the same as that of the first embodiment. When the internal refrigerant leakage detector 21 detects the refrigerant leakage (time t ₀ ), the refrigerant leakage indicator 29 indicates the refrigerant leakage. At the same time, the on-off valve 11 is closed by the controller 26 regardless of whether the refrigeration cycle is operating or stopped.
The compressor 9 is continuously operated as it is, the refrigerant recovery operation is performed, the fan 31 is reversely rotated, and the damper 43 is closed. Since the compressor 9 is operated with the on-off valve 11 closed, the refrigerant in the refrigeration cycle is recovered in the condenser 10 as a high-pressure liquid refrigerant. Further, since the damper 43 is closed and the fan 31 rotates in the reverse direction, the air in the freezer compartment 5 is sucked in reverse by the fan 31 from the freezer compartment outlet 35 and passes around the evaporator 13 in the air passage 32. , And is discharged to the outside of the refrigerator from the drain pipe 38 that also serves as a communication hole.

At time t ₁ after the first set time has elapsed, the refrigerant recovery operation ends and the compressor 9 stops. When the refrigerant recovery operation ends, the refrigerant leakage into the refrigerator stops, and the refrigerant concentration in the refrigerator gradually decreases. When the refrigerant leakage is no longer detected (time t ₂ ), the fan 31 that is rotating in the reverse direction is stopped, and the refrigeration cycle is not restarted while the refrigerant leakage indicator 29 indicates the refrigerant leakage.

As described above, in the present embodiment, even if the refrigerant leaks inside the refrigerator, the refrigerant is collected to reduce the refrigerant leak, and the air inside the refrigerator is forcibly discharged to the outside of the refrigerator. The risk of explosion inside the refrigerator can be avoided.

In the above embodiment, the drain pipe 38 is used as a communication hole for communicating the inside and the outside of the refrigerator, but a communication hole closed by a damper during normal operation may be separately provided for discharging the refrigerant gas. The same effect can be obtained. Also,
When the refrigerant gas leaked into the refrigerator is discharged to the outside by rotating the fan 31 in the reverse direction, the inside of the freezer compartment 5 or the refrigerator compartment 6 is communicated with the outside to facilitate the discharge, and an inflow path for external air. A ventilation mechanism is provided, and when the inside of the refrigerator reaches a predetermined negative pressure, the ventilation mechanism is opened to communicate the inside and the outside of the refrigerator, or a signal for reversing the fan 31 opens the inside of the refrigerator. A valve mechanism that communicates with the outside of the refrigerator may be provided, and the valve mechanism may be normally closed to close the vent hole. This makes it easy to replace the air outside the refrigerator with the air containing the refrigerant gas inside the refrigerator.

Furthermore, in the present embodiment, a description has been given by taking a mixed refrigerant of propane and isobutane as an example of the flammable refrigerant.
The same effect can be obtained with a propane single refrigerant or a flammable refrigerant such as HFC-152a.

[0030]

According to the present invention, in a refrigerator equipped with a refrigeration cycle in which a mixed refrigerant containing a flammable refrigerant or a flammable refrigerant consisting of a single component is installed, a connecting portion between an evaporator and a pipe is a heat insulating material. By providing the inside, it is possible to prevent the refrigerant from leaking inside the refrigerator. Further, by providing a discharge hole that communicates the inside and outside of the refrigerator, and by providing a blower device that forcibly discharges the air inside the refrigerator to the outside through the communication hole when the refrigerant leakage detector detects a refrigerant leak, the refrigerant inside the refrigerator Even if a leak occurs, the refrigerant concentration can be reduced and explosion can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main configuration of a refrigerator according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing details of the evaporator according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a main configuration of a refrigerator according to a second embodiment of the present invention.

FIG. 4 is a time chart showing control at the time of refrigerant leakage detection in the embodiment of the present invention.

[Explanation of symbols]

1 Refrigerator 2 Outer box 3 Inner box 4 Insulating material 5 Freezer 6 Refrigerator 7 Freezer door 8 Refrigerator door 9 Compressor 10 Condenser 11 Open / close valve 12 Capillary tube 13 Evaporator 14 Receiver tank 15 Check valve 16 Discharge pipe 17 Liquid Piping 18 Gas Piping 19 Suction Piping 20 Electrical Box 21 Refrigerant Leak Detector in Cabinet 22 External Refrigerant Leak Detector 23 Evaporator Temperature Detector 24 Freezer Chamber Temperature Detector 25 Refrigerator Chamber Temperature Detector 26 Controller 27 Compressor Drive device 28 Defrost heater control device 29 Refrigerant leak indicator 30 Fan drive device 31 Fan 32 Air passage 33 Freezer compartment inlet 34 Refrigerator compartment inlet 35 Freezer compartment outlet 36 Refrigerator compartment outlet 37 Water pan 38 Drain pipe 39 Partition Wall 40 Evaporating dish 41 Refrigerant piping 42 Fin 43 Damper 50 Defrost heater 51 Defrost heater Degree detector 60 freezing compartment door opening and closing detector 61 refrigerating chamber door opening and closing detector

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location F25D 23/00 305 F25D 23/00 305D (72) Inventor Nobuyuki Isoshima 502 Kintatecho, Tsuchiura City, Ibaraki Prefecture (72) Inventor Hiroshi Iwata 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture

Claims (10)

[Claims] 1. A heat-insulating box body formed by inserting a heat-insulating material between an outer box and an inner box, a compressor, a condenser, a decompressor, and an evaporator are connected by piping, and a combustible refrigerant is included. In a refrigerator equipped with a refrigeration cycle in which a flammable refrigerant composed of a mixed refrigerant or a single component is sealed, the evaporator is installed inside the inner box, and the connection between the evaporator and the pipe is provided inside the heat insulating material. A refrigerator characterized by that. 2. A heat-insulating box body in which a heat insulating material is inserted between an outer box and an inner box, and a compressor, a condenser, a decompressor, and an evaporator are connected by piping, and a flammable refrigerant is included. In a refrigerator equipped with a refrigeration cycle in which a flammable refrigerant composed of a mixed refrigerant or a single component is enclosed, a refrigerant leakage detector is provided around the evaporator and a communication hole for communicating the inside and outside of the refrigerator is provided, and the refrigerant leakage A refrigerator provided with a blower for forcibly discharging the air inside the refrigerator to the outside through the communication hole when the detector detects a refrigerant leak. 3. The refrigerator according to claim 2, wherein the evaporator is installed in the inner box. 4. The refrigerator according to claim 2, wherein a connecting portion between the evaporator and the pipe is provided inside the heat insulating material. 5. A defrost heater for melting the frost of the evaporator, a discharge pipe for discharging the water melted by the defrost heater to the outside of the refrigerator, and a blower for blowing the air inside the refrigerator to the discharge pipe. The refrigerator according to claim 1, wherein the refrigerator is a refrigerator. 6. A defrosting heater for melting frost of the evaporator, and a discharge pipe for discharging the water melted by the defrosting heater to the outside of the refrigerator, the discharge pipe being used as a communication hole. The refrigerator according to claim 2, wherein the refrigerator is configured. 7. A control device comprising a defrost heater temperature detector for detecting the temperature of the defrost heater, wherein the control device is provided to stop energization of the defrost heater when the temperature of the defrost heater exceeds a set temperature. The refrigerator according to claim 5, wherein the refrigerator is a refrigerator. 8. A refrigerant leakage detector provided around the evaporator, and a controller for controlling the operation of the compressor by using an output signal of the refrigerant leakage detector as an input. The refrigerator according to claim 1, 5, or 7. 9. The control system according to claim 2, further comprising a controller that controls the operation of the compressor by using the output signal of the refrigerant leak detector as an input. Refrigerator described in. 10. The refrigerator according to claim 1, wherein the pipe forming the evaporator is one seamless pipe.