JP5007185B2 - Refrigeration apparatus, control method and control program for refrigeration apparatus - Google Patents

Description

  The present invention relates to a refrigeration apparatus, a control method for a refrigeration apparatus, and a control program, and more particularly to a technique for suppressing frost formation on a cooler.

In recent years, large-scale retail stores such as supermarkets sell various foods such as meat and fresh fish, frozen foods and ice creams. These foods are stored and displayed in a refrigerated or refrigerated showcase (hereinafter collectively referred to as a low-temperature showcase) as a refrigeration apparatus so that customers can easily take them while performing appropriate temperature control.
The low-temperature showcase includes a showcase body for storing food, and a refrigerator having a refrigerant circuit composed of a compressor, a decompression device, a condenser, an evaporator (cooler), and the like. The structure is such that cold air is supplied to the food in the case body by a cooler fan.

In this type of low temperature showcase, frost may form on the evaporator of the refrigerator during operation. Therefore, a defrosting operation using hot gas or a defrosting heater is performed (for example, refer to Patent Document 1). However, when a store such as a supermarket is opened, a request from the user not to perform this defrosting operation as much as possible. There is. In order to meet this demand, the size of the cooler is increased and the defrosting interval is made as long as possible.
JP 2006-207885 A

However, in the conventional configuration, there is a problem that even if the defrosting interval can be extended, the operation time required for the defrosting operation is increased by the size of the cooler.
In view of this, for example, it is proposed to divide a large-sized cooler into two parts and to attach defrosting means such as a defrost heater to each of the two divided coolers to shorten the defrosting operation time. However, when two coolers are installed vertically in a cooling duct extending in the vertical direction, for example, frost or ice of the downstream cooler falls on the upstream cooler, and the defrost time of the upstream cooler There is a problem such as becoming longer.

Moreover, in order to lengthen a defrost interval, forming the fin pitch of the upstream of the cool air of a cooler roughly is performed. However, in the conventional configuration, the liquid refrigerant is introduced to the downstream side of the cool air of the cooler, and flows in the upstream side in order, and is led out from the upstream side of the cool air of the cooler. There has been a problem that frost forms on the most upstream side of the fin pitch, which rather reduces the cooling capacity.
In order to solve the above problems, an object of the present invention is to provide a refrigeration apparatus, a refrigeration apparatus control method, and a control program capable of suppressing frost formation on a cooler and extending a defrosting operation interval. is there.

In order to solve the above problems, the present invention relates to a compressor, an evaporator having a heat transfer tube and a plurality of fins, an expansion valve for adjusting a flow rate of a refrigerant flowing into the evaporator, and a fan for blowing air to the evaporator. And a frost-proof sensor for detecting a refrigerant temperature at the predetermined position at a predetermined position of the heat transfer tube of the evaporator , and a fin pitch of the fins and a pitch between the adjacent heat transfer tubes. Is formed closer to the downstream side of the refrigerant of the defrost sensor than the upstream side, and the opening degree of the expansion valve is controlled so that the temperature of the refrigerant detected by the defrost sensor becomes higher than a predetermined anti-frost temperature. A control unit is provided .

In this case, the air to be cooled may be caused to flow from the downstream side of the refrigerant toward the upstream side of the refrigerant by the fan .
Moreover, you may make it provide the temperature sensor which detects the temperature of the said refrigerant | coolant in the said predetermined position.
Further, a humidity sensor for detecting the humidity of the air to be cooled may be provided, and the frosting prevention temperature may be set to a higher temperature when the detected humidity is higher than a predetermined reference humidity.
The fan may be arranged in a cooling duct of a refrigeration apparatus main body and configured to circulate the air to be cooled.

The present invention also includes a compressor, an evaporator having a heat transfer tube and a plurality of fins, an expansion valve that adjusts the flow rate of the refrigerant flowing into the evaporator, and a fan that blows air to the evaporator. In the control method of a refrigeration apparatus for controlling a refrigeration apparatus, the evaporator includes a defrost sensor that detects a refrigerant temperature at the predetermined position at a predetermined position of a heat transfer tube , and the fin pitch of the fins and the adjacent transmission lines. The pitch between the heat pipes is formed closer to the downstream side of the refrigerant of the defrost sensor from the upstream side, and the temperature of the refrigerant detected by the defrost sensor is higher than a predetermined frost prevention temperature of the expansion valve. The opening degree is controlled .

  According to the present invention, the fin pitch on the downstream side of the predetermined position of the evaporator, where frost formation is unlikely to occur, is made dense, and the refrigerant temperature at the predetermined position is equal to or higher than the temperature at which frost formation hardly occurs. While achieving both prevention of frost formation on the downstream side of the refrigerant and improvement of heat exchange efficiency, frost formation can be suppressed also on the upstream side of the refrigerant, and a defrosting operation interval can be increased.

Next, preferred embodiments of the present invention will be described with reference to the drawings.
[1] First Embodiment FIG. 1 is a longitudinal sectional view of a refrigerated showcase as a refrigeration apparatus according to a first embodiment of the present invention.
The refrigerated showcase 1 is a multistage open type whose front is opened and a cooling unit built-in type in which liquid refrigerant is supplied from a built-in cooling unit. The display case body 2 is provided with a four-stage display shelf 3 at the opening thereof, and an inner layer air curtain (the flow is indicated by an arrow A) and an outer layer air curtain (the flow) at the front of the display shelf 3. Is indicated by an arrow in the B direction).
A cooling duct 4 is formed in the showcase body 2 so as to surround the display shelf 3, and a cooler fan 5 is disposed below the cooling duct 4. Further, an evaporator 6 as a cooling heat exchanger is disposed in a vertical portion of the cooling duct 4. Cooling air is circulated by the cooling duct 4, the cooling fan 5, the evaporator 6, the cold air inlet 7, and the cold air outlet 8 and supplied around the display shelf 3.
The showcase body 2 is formed with an air duct 9 so as to surround the cooling duct 4, and an air curtain fan (not shown) is disposed in the air duct 9. 11 is to generate an air curtain.
In addition, a compressor 42, a condenser 43 that is a heat exchanger, and the like are disposed in the lower portion of the showcase body 2 and below the heat insulating wall. The condenser 43 is cooled by the outside air taken from the intake holes of the front panel 40, and the air after heat exchange is blown rearward from the exhaust holes of the rear panel 41.

FIG. 2 is an explanatory diagram of the configuration around the evaporator.
An electronic expansion valve 15 as a decompression device is connected to the refrigerant upstream side of the evaporator 6, and an inlet temperature sensor 16 is disposed on the inlet pipe of the evaporator 6 on the refrigerant downstream side of the electronic expansion valve 15. An outlet temperature sensor 17 is disposed at the outlet pipe of the evaporator 6.
Furthermore, a defrost sensor (temperature sensor) 19 is attached to a predetermined position of the heat transfer tube 18 constituting the evaporator 6.
The fin pitch of the fins of the evaporator 6 (hereinafter referred to as the first fin pitch) located on the refrigerant downstream side of the attachment position of the defrost sensor 19 is located on the refrigerant upstream side of the attachment position of the defrost sensor 19. It is formed more densely than the fin pitch of the fins located (hereinafter referred to as the second fin pitch).

Specifically, the first fin pitch of the fins located downstream of the refrigerant from the attachment position of the defrost sensor 19 is approximately 2 to 5 mm, and the fins are located downstream of the refrigerant from the attachment position of the anti-frost sensor. The second fin pitch is approximately 10 mm.
In this case, the portion of the evaporator 6 located on the downstream side of the refrigerant with respect to the attachment position of the defrost sensor 19 is arranged upstream of the cooling air flow FW and The portion located upstream of the refrigerant is disposed downstream of the cooling air flow FW.

FIG. 3 is a schematic configuration diagram showing the refrigeration cycle of the first embodiment and its control system.
As shown in FIG. 3, the refrigeration cycle includes an evaporator 6, an electronic expansion valve 15, a compressor 42, a condenser 43, a liquid receiver 44, and the like. A condenser fan 45 for promoting heat exchange in the condenser 43 is disposed in the vicinity of the condenser 43, and a defrosting heater 21 for performing defrosting is disposed in the vicinity of the evaporator 6. Yes. In addition, liquid refrigerant or gas refrigerant flows through the refrigerant pipes 51 to 56.
In the upper part of the refrigerated showcase 1, a showcase-side control unit (CU) 25 that drives and controls the cooler fan 5, the electronic expansion valve 15, and the defrosting heater 21 is installed.
The showcase side control unit (CU) 25 is configured as a microcomputer including a CPU, an input / output interface, a ROM, a RAM, a timer counter, and the like. Various sensor output signals such as an inlet temperature detection signal TI, an outlet temperature detection signal TO from the outlet temperature sensor 17 and a defrost temperature detection signal TF from the defrost sensor are input.

On the other hand, a cooling unit side control unit (CU) 60 that drives and controls the compressor 42, the condenser fan 45, and the like is installed in the lower part of the refrigerated showcase 1. The cooling unit side control unit (CU) 60 is configured as a microcomputer including a CPU, an input / output interface, a ROM, a RAM, a timer counter, and the like. Further, the showcase-side control unit (CU) 25 and the cooling unit-side control unit (CU) 60 are connected by a communication line 61 and exchange signals with each other.
Next, the operation of the embodiment will be described.
When the operation of the refrigeration cycle is started, as shown in FIG. 3, the gas refrigerant in the liquid receiver 44 is sucked into the compressor 42 via the refrigerant pipe 58 as indicated by a solid line arrow. The gas refrigerant is compressed in the compressor 42 to become a high temperature and a high pressure, and then flows into the condenser 43 via the refrigerant pipe 51 and condenses and liquefies while flowing through the condenser 43. Thereafter, the liquid refrigerant is branched from the refrigerant pipe 52 to the refrigerant pipe 53, decompressed by the electronic expansion valve 15 interposed in the refrigerant pipe 53, and flows into the evaporator 6.
The liquid refrigerant evaporates and vaporizes in the evaporator 6, then circulates to the liquid receiver 44 through the refrigerant pipes 54 and 55, is stored in the liquid receiver 44, and is compressed again through the refrigerant pipe 58. It is sucked into the machine 42.

In the case of the first embodiment, after the cool air around the display shelf 3 is sucked into the cooling duct 4 from the cool air suction port 7 by the cooler fan 5, Heat is exchanged and cooled by the refrigerant downstream side of the evaporator 6 having a dense fin pitch, which is a fin pitch, and dehumidification is performed.
Then, the cooling air that has been slightly cooled and dehumidified is cooled to a predetermined temperature by the refrigerant upstream side of the evaporator 6 having the coarse fin pitch that is the second fin pitch, and is directed from the cold air outlet 8 toward the display shelf 3. And blown out. Moreover, the air which produces | generates an air curtain is blown in toward the air suction inlet 10 from the air blower outlet 11, after being suck | inhaled in the ventilation duct 9 from the air suction inlet 10 with the fan for air curtains.

The evaporator 6 has a surface temperature below freezing point due to latent heat of vaporization accompanying the vaporization of the liquid refrigerant, and cools the air passing between the cooling fins. The cooled air is circulated in the showcase body 2 by the cooler fan 5 as indicated by the arrow A (FIG. 1), and the products displayed on the display shelf 3 are cooled to a predetermined temperature.
In this case, the control unit 25 performs frosting prevention control in parallel with the cooling control.

Here, the frosting prevention control will be described.
FIG. 4 is a process flowchart of frost prevention control according to the first embodiment.
First, the control unit 25 determines whether or not the temperature detected by the defrost sensor 19 exceeds 1 ° C. (step S11). Here, if the detection temperature of the defrost sensor 19 is 1 ° C. or lower, the possibility that frosting occurs on the refrigerant downstream side of the evaporator 6 increases.
In step S11, when the detected temperature of the defrost sensor 19 exceeds 1 ° C. (step S11; Yes), the control unit 25 corresponds to the inlet temperature detection signal TI output from the inlet temperature sensor 16. Based on the evaporator inlet temperature and the outlet temperature detection signal TO output from the outlet temperature sensor 17, the electronic expansion valve is set so that the degree of superheat becomes a predetermined degree of superheat (8 ° C. in this embodiment). 15 is controlled (step S12), the process proceeds to step S11 again, and the same process is repeated thereafter.

When the detection temperature of the defrost sensor is 1 ° C. or lower in the determination of step S11 (step S11; No), the control unit 25 detects the detection corresponding to the defrost temperature detection signal TF output from the defrost sensor 19. Defrost control is performed to control the opening of the electronic expansion valve 15 so that the temperature becomes 1 ° C. (step S13).
Next, the control unit 25 is based on the evaporator inlet temperature corresponding to the inlet temperature detection signal TI output from the inlet temperature sensor 16 and the evaporator outlet temperature corresponding to the outlet temperature detection signal TO output from the outlet temperature sensor 17. It is determined whether or not the degree of superheat is a predetermined degree of superheat (less than 3 ° C. in the present embodiment) at the time of defrost control (step S14).
If it is determined in step S14 that the degree of superheat is less than the predetermined degree of superheat (= 3 ° C.) (step S14; Yes), the process proceeds to step S12, and the same process is performed thereafter.

On the other hand, if the degree of superheat is greater than or equal to the predetermined superheat degree in the determination in step S14 (step S14; No), the process proceeds to step S13, and the defrost control is performed to control the opening degree of the electronic expansion valve 15. Will be continued.
Further, when the cooling operation is continued, frost adheres to the upstream side of the refrigerant of the evaporator 6, so the defrosting operation is performed at an appropriate interval. This defrosting operation is performed by stopping the operation of the compressor 42 and fully closing the electronic expansion valve 15 and energizing the defrosting heater 21. This defrosting operation starts counting with a timer (not shown) simultaneously with the start of the defrosting operation, and is canceled and stopped when this timer counts a predetermined time.
By performing the control as described above, according to the first embodiment, the amount of frosting is reduced, the defrosting cycle time is extended, and the non-frosted portion of the evaporator is subjected to fin pitch and transmission. If the heat exchange efficiency remains the same by increasing the pitch of the heat tubes, the evaporator, and thus the refrigeration apparatus can be downsized. Moreover, if the size of the refrigeration apparatus remains the same, the capacity of the refrigeration apparatus can be improved.

[2] Second Embodiment In the first embodiment, the opening degree of the electronic expansion valve is controlled when the defrost control is performed. However, when a variable capacity inverter-controlled compressor is used, the compressor It is also possible to configure to control the operating frequency.
FIG. 5 is a process flowchart of frost prevention control according to the second embodiment.
In the following description, it is assumed that the compressor 42 shown in FIG. 3 is an inverter-controlled compressor.
First, the control unit 25 determines whether or not the detected temperature of the defrost sensor 19 exceeds 1 ° C. (step S21). Here, if the detection temperature of the defrost sensor 19 is 1 ° C. or lower, the possibility that frosting occurs on the refrigerant downstream side of the evaporator 6 increases.

If it is determined in step S21 that the detected temperature of the defrost sensor 19 exceeds 1 ° C. (step S21; Yes), the control unit 25 sets the internal temperature corresponding to the output of the internal temperature sensor (not shown). The constant temperature control is performed so as to be 5 ± 3 ° C. (step S22), the process is again transferred to step S21, and the same process is repeated thereafter.
If the detection temperature of the defrost sensor is 1 ° C. or lower in the determination in step S21 (step S21; No), the control unit 25 detects the detection corresponding to the defrost temperature detection signal TF output from the defrost sensor 19. Anti-frost control is performed to control the operating frequency of the compressor 42 so that the temperature becomes 1 ° C. (step S23).
Next, the control unit 25 determines whether or not the internal temperature corresponding to the output of the internal temperature sensor (not shown) exceeds a predetermined temperature during defrost control (8 ° C. in the present embodiment) (step S24). ).
In the determination of step S24, when the internal temperature corresponding to the output of the internal temperature sensor (not shown) exceeds the predetermined temperature (8 ° C. in this embodiment) at the time of defrost control (step S24; Yes). The process proceeds to step S22, and the same process is performed thereafter.

On the other hand, in the determination of step S24, when the internal temperature corresponding to the output of the internal temperature sensor (not shown) is equal to or lower than the predetermined temperature (8 ° C. in this embodiment) at the time of defrost control (step S24). No), the process proceeds to step S23, and the defrosting control is performed to control the operation frequency of the compressor 42 to be lowered.
By performing the control as described above, according to the second embodiment, the amount of frost is reduced, the defrost cycle time is extended, and the portion of the evaporator that is not frosted is subjected to fin pitch and transmission. If the heat exchange efficiency remains the same by increasing the pitch of the heat tubes, the evaporator, and thus the refrigeration apparatus can be downsized. Moreover, if the size of the refrigeration apparatus remains the same, the capacity of the refrigeration apparatus can be improved.

[3] Third Embodiment In each of the above embodiments, the control unit 25 controls the detection temperature of the defrost sensor to be 1 ° C. or higher when performing the defrost control. Depending on the ambient humidity of 1 or the cold air temperature circulating in the cabinet, frosting may occur.
Therefore, in the third embodiment, as shown in FIG. 1, a humidity sensor 76 that outputs a humidity detection signal FM corresponding to the detected humidity is disposed in the vicinity of the air suction port 10 and corresponds to the detected cold air temperature. A cold air temperature sensor 77 that outputs a cold air temperature detection signal TC is disposed in the vicinity of the evaporator 6, and the defrost control is changed based on the detected humidity or cold air temperature.
Specifically, when the humidity corresponding to the humidity detection signal FM output from the humidity sensor 76 is higher than a predetermined humidity, the control unit 25 increases the detected temperature during defrost control (in the embodiment, 1). Set the temperature to 3 ° C.
Similarly, when the cold air temperature corresponding to the cold air temperature detection signal TC output from the cold air temperature sensor 77 is higher than the predetermined cold air temperature, the control unit 25 sets the detected temperature during the defrost control to a higher temperature (implementation). In the embodiment, 1 ° C. is set to 3 ° C.).
By comprising as mentioned above, frosting can be prevented more reliably and it becomes possible to take a long defrosting interval.

[4] Fourth Embodiment Each of the above embodiments is a case of a low-temperature showcase, but the fourth embodiment is an embodiment when the present invention is applied to an outdoor unit.
FIG. 6 is a schematic configuration diagram of a heat exchanger of the outdoor unit according to the fourth embodiment.
The outdoor unit 70 is roughly provided with an outdoor fan 71 and an outdoor heat exchanger 72.
A defrost sensor (temperature sensor) 74 is attached to a predetermined position of the heat transfer tube 73 constituting the outdoor heat exchanger 72.
The fin pitch of the fins of the outdoor heat exchanger (the portion surrounded by the broken line 75 in the drawing) located on the downstream side of the refrigerant from the attachment position of the defrost sensor 74 is smaller than that of the attachment position of the defrost sensor 74. The fin pitch of the fin located in the upstream is formed densely.
Furthermore, the heat transfer tube 73A has a dense pitch at a portion where the fin pitch is dense.

  As a result of these configurations, when the outdoor heat exchanger 72 functions as an evaporator, the portion surrounded by the broken dashed line 75 where the fin pitch and the pitch of the heat transfer tubes are enclosed is a normal usage mode (predetermined humidity state, outside air temperature). In this state, it is considered that frosting will not occur, and in these parts, the heat exchange efficiency will be improved, so if the heat exchange efficiency required as a specification remains the same, the outdoor heat exchanger, It is possible to reduce the size of the outdoor unit. Moreover, if the size of the outdoor unit remains the same, the capacity of the refrigeration apparatus can be improved.

[5] Fifth Embodiment FIG. 7 is a schematic configuration diagram of a heat exchanger of an outdoor unit according to a fifth embodiment.
The difference from the outdoor heat exchanger 72 of the fourth embodiment is that the two heat exchangers 81 and 82 are connected by a connecting pipe 83, and a defrosting sensor 84 is attached to the connecting pipe 83. The heat exchange on the upstream side of the refrigerant is performed using the fin pitch (first fin pitch) of the heat exchanger (heat exchanger downstream of the connecting pipe) 82 and the pitch of the heat transfer pipe 86 (first heat transfer pipe pitch). The fin pitch (second fin pitch) of the vessel 81 and the pitch of the heat transfer tube 85 (second heat transfer tube pitch) are more dense.
According to this configuration, compared to the fourth embodiment, the taken-in outside air is heat-exchanged by the heat exchanger 82 on the downstream side of the refrigerant having the dense fin pitch that is the first fin pitch and the first heat transfer tube pitch. In addition, dehumidification is performed.

The cooling air that has been slightly cooled and dehumidified is heat-exchanged to a predetermined temperature by the heat exchanger 81 on the refrigerant upstream side having the coarse fin pitch that is the second fin pitch and the second heat transfer pipe pitch. Become.
Therefore, since dry air is introduced to the upstream side of the refrigerant, it is possible to reduce the frosting amount of the heat exchanger 81 on the upstream side of the refrigerant, to extend the defrost cycle time and to heat the downstream side of the refrigerant. For the non-frosted portion corresponding to the exchanger 82, the fin pitch and the pitch of the heat transfer tubes 86 are made dense so that the heat exchange efficiency remains the same. Can be achieved. Moreover, if the size of the refrigeration apparatus remains the same, the capacity of the refrigeration apparatus can be improved.

[6] Modification of Embodiment [6.1] First Modification In the third embodiment described above, the reference temperature of the anti-frost sensor is changed according to the ambient humidity or cold air temperature (in the embodiment, (Changed from 1 ° C to 3 ° C). However, when the ambient humidity is high or the cold air temperature is high, the anti-frosting sensor is provided at a plurality of locations, and is arranged more upstream of the refrigerant. It is also possible to determine whether or not the detection temperature of the anti-frost sensor has exceeded the same temperature (for example, 1 ° C.) in all the anti-frost sensors.

[6.2] Second Modification In the above description, in the evaporator (heat exchanger) on the downstream side of the refrigerant, the fin pitch or the heat transfer tube pitch is made dense, but the corresponding portion is slit. A configuration using so-called slit fins having high heat exchange efficiency may be adopted.

[6.3] Third Modification In the above description, the evaporator (heat exchanger) on the downstream side of the refrigerant has a structure in which the fin pitch or the heat transfer tube pitch is made dense. A configuration using a so-called inner surface grooved tube in which a groove is provided and heat exchange efficiency is high may be adopted.

[6.4] Fourth Modification In the above description, the evaporator (heat exchanger) on the upstream side of the refrigerant adopts a configuration in which the fin pitch or the heat transfer pipe pitch is coarsened. Further, defrosting coating or water breakage promotion coating may be performed.

[6.5] Fifth Modification In the above description, the case where the present invention is applied to a multistage open type refrigerated showcase has been described. is there.

It is a longitudinal cross-sectional view of the refrigerated showcase as a freezing apparatus which concerns on 1st Embodiment of this invention. It is structure explanatory drawing of an evaporator periphery. It is a schematic block diagram which shows the refrigerating cycle of 1st Embodiment, and its control system. It is a process flowchart of the frost prevention control of 1st Embodiment. It is a process flowchart of the frosting prevention control of 2nd Embodiment. It is a schematic block diagram of the heat exchanger of the outdoor unit of 4th Embodiment. It is a schematic block diagram of the heat exchanger of the outdoor unit of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerated showcase 2 Showcase body 3 Display shelf 4 Cooling duct 5 Cooler fan 6 Evaporator 7 Cold air inlet 8 Cold air outlet 9 Air duct 10 Air inlet 11 Air outlet 15 Electronic expansion valve 16 Inlet temperature sensor 17 Outlet Temperature sensor 18 Heat transfer tube 19 Defrost sensor 21 Defrost heater 25 Control unit 61 Communication line 70 Outdoor unit 71 Outdoor fan 72 Outdoor heat exchanger 74 Defrost sensor 76 Humidity sensor 77 Cold air temperature sensor 84 Defrost sensor 85 Heat transfer tube 86 Heat transfer tube FM Humidity detection signal TC Cold air temperature detection signal TF Defrost temperature detection signal TI Inlet temperature detection signal TO Outlet temperature detection signal

Claims (6)

In a refrigeration apparatus comprising: a compressor; an evaporator having a heat transfer tube and a plurality of fins; an expansion valve that adjusts a flow rate of refrigerant flowing into the evaporator; and a fan that blows air to the evaporator.
A defrost sensor for detecting the refrigerant temperature at the predetermined position is provided at a predetermined position of the heat transfer tube of the evaporator , and the fin pitch of the fins and the pitch between the adjacent heat transfer tubes are set downstream of the refrigerant of the defrost sensor. On the side, denser than the upstream side,
A refrigeration apparatus comprising: a control unit that controls an opening degree of the expansion valve so that a temperature of the refrigerant detected by the defrost sensor is higher than a predetermined anti-frosting temperature. The refrigerating machine請Motomeko 1,
The refrigeration apparatus characterized in that the air to be cooled is caused to flow from the refrigerant downstream side of the evaporator toward the refrigerant upstream side by the fan. The refrigeration apparatus according to claim 1 or 2 ,
A refrigeration apparatus comprising a temperature sensor for detecting a temperature of the refrigerant at the predetermined position. The refrigeration apparatus according to any one of claims 1 to 3 ,
A humidity sensor for detecting the humidity of the air to be cooled;
When the detected humidity is higher than a predetermined reference humidity, the frost prevention temperature is set to a higher temperature. The refrigeration apparatus according to any one of claims 1 to 4 ,
The fan is disposed in a cooling duct of the refrigeration apparatus body,
A refrigeration apparatus configured to circulate the air to be cooled. Refrigeration for controlling a refrigeration apparatus comprising a compressor, an evaporator having a heat transfer tube and a plurality of fins, an expansion valve for adjusting the flow rate of refrigerant flowing into the evaporator, and a fan for blowing air to the evaporator In the device control method,
The evaporator includes a defrost sensor that detects a refrigerant temperature at the predetermined position at a predetermined position of the heat transfer tube , and the fin pitch of the fins and the pitch between the adjacent heat transfer tubes are the refrigerant of the defrost sensor. Formed more densely on the downstream side than the upstream side,
A control method for a refrigeration apparatus , wherein the opening degree of the expansion valve is controlled so that the temperature of the refrigerant detected by the defrost sensor is higher than a predetermined anti-frost temperature .

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