JP7456457B2 - Showcase - Google Patents

Description

This disclosure relates to showcases.

A known showcase is provided with display shelves arranged in a storage chamber inside the case body on which products are placed and displayed, a circulation means for circulating air inside the storage chamber between the storage chamber and an air passage, a cooling means for cooling the air circulated by the circulation means, and a heating means arranged on the display shelves, and which operates the heating means while the cooling means and circulation means are stopped (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2017-225551

In this way, in the showcase shown in Patent Document 1, when heating is performed by the heating means (heater) provided in the display shelf, the circulation of air inside the storage room (storage room) is stopped. . Therefore, if refrigerant leaks from the storage room side of the refrigerant circuit that serves as a cooling means for cooling the air during heating by the heater, the leaked refrigerant will not be diffused and will remain in the storage room, around the showcase, etc. There is a possibility that a region where the refrigerant concentration exceeds a certain level is formed.

This disclosure has been made to solve such problems. The purpose of this is to use a showcase that is equipped with a refrigerant circuit to cool the inside of the storage room and a heater that heats the inside of the storage room, and stops the circulation of air inside the storage room during the heat retention operation where the heater heats the inside of the storage room and keeps it warm. In the event that refrigerant leaks from the storage compartment side of the refrigerant circuit during heat retention operation, it is possible to reduce the amount of refrigerant leakage, and as a result, the leaked refrigerant stagnates to form an area where the refrigerant concentration exceeds a certain level. The goal is to provide a showcase that can suppress this.

The showcase according to this disclosure includes a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order through refrigerant piping filled with refrigerant, and a heater for keeping stored items in a storage room warm. , a blocking means installed in the refrigerant pipe between the condenser and the evaporator and capable of blocking the flow of the refrigerant, the evaporator being connected to the inside of the storage chamber through the outlet. the compressor and the condenser are located in a machine room; further comprising: a condenser fan disposed within a room for generating an air flow passing through the condenser; and a control device for controlling the compressor, the heater, the evaporator fan, the condenser fan and the blocking means. The storage chamber and the machine room are formed in one housing, the opening of the storage chamber and the air supply port of the machine room are disposed on the same side of the housing, and the control device includes: Before starting heat retention by the heater, performing a recovery operation in which the compressor is operated in a state where the flow of the refrigerant is blocked by the blocking means to recover the refrigerant to the machine room side of the refrigerant circuit; After the recovery operation, the compressor is stopped and heat retention by the heater is started, and during the recovery operation, the evaporator fan is stopped and the rotation speed is higher than that at which the refrigerant leaking in the refrigerant circuit can be diffused. Operate the condenser fan.

According to the showcase according to this disclosure, it is possible to reduce the amount of refrigerant leakage when refrigerant leaks from the storage chamber side of the refrigerant circuit during the heat retention operation.

1 is a diagram schematically showing the overall configuration of a showcase according to Embodiment 1 of this disclosure. 1 is a block diagram showing the configuration of a control system of a showcase according to Embodiment 1 of this disclosure. FIG. FIG. 2 is a flow diagram illustrating an example of the operation of the showcase according to Embodiment 1 of this disclosure. It is a figure which shows typically the modification of the structure of the showcase based on Embodiment 1 of this disclosure. 10A and 10B are diagrams illustrating schematic diagrams of modified examples of the configuration of the showcase according to the first embodiment of the disclosure. It is a figure which shows typically the modification of the structure of the showcase based on Embodiment 1 of this disclosure. FIG. 11 is a flow diagram showing another example of the operation of the showcase according to the first embodiment of the disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes for carrying out this disclosure will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are given the same reference numerals, and overlapping explanations will be simplified or omitted as appropriate. In the following description, for convenience, the positional relationship of each structure may be expressed based on the illustrated state. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

Embodiment 1.
Embodiment 1 of this disclosure will be described with reference to FIGS. 1 to 7. FIG. 1 is a diagram schematically showing the overall configuration of the showcase. FIG. 2 is a block diagram showing the configuration of the control system of the showcase. FIG. 3 is a flow diagram showing an example of the operation of the showcase. 4 to 6 are diagrams schematically showing modified examples of the structure of the showcase. FIG. 7 is a flowchart showing another example of the operation of the showcase.

The showcase 100 according to this embodiment is an open showcase that is installed in a supermarket, convenience store, etc., and stores and displays drinks, foods, and the like. Note that the showcase 100 may be a closed (reach-in) showcase equipped with a door that opens and closes the storage room.

As shown in FIG. 1, the showcase 100 includes a housing 1. As shown in FIG. The housing 1 has a rectangular box shape as a whole. A storage room 3 and a machine room 2 are formed in the housing 1 . The storage chamber 3 is arranged on the upper side of the housing 1. The lower side of the housing 1 is a machine room 2. The configuration example described here is a so-called integrated showcase 100 in which a storage room 3 and a machine room 2 are provided in one housing 1. However, the configuration is not limited to this, and the storage room 3 and the machine room 2 may be provided in separate housings.

The storage room 3 is a space in which stored items such as beverages and fresh foods to be cooled can be stored. A plurality of display shelves 4 for displaying fresh foods and the like are attached to the storage room 3 and arranged in a vertical direction. An opening 5 is formed in at least one surface of the storage chamber 3. Foods can be taken out and placed on the display shelf 4 through this opening 5. In the configuration example described here, there is an opening 5 in the front of the storage chamber 3. That is, the storage chamber 3 is opened at the front of the housing 1.

The showcase 100 includes a refrigerant circuit. As shown in FIG. 1, the refrigerant circuit includes a compressor 11, a condenser 12, an expansion valve 13, and an evaporator 14, which are cyclically connected in this order by a refrigerant pipe 17. A refrigerant circuit including the refrigerant pipe 17 and the like is filled with refrigerant.

From the viewpoint of protecting the global environment, it is desirable to use a refrigerant with a small global warming potential (GWP) as the refrigerant sealed in the refrigerant circuit. Furthermore, the refrigerant sealed in the refrigerant circuit is flammable. This refrigerant has a higher average molecular weight than air. That is, the refrigerant has a higher density than air and is heavier than air at atmospheric pressure. Therefore, refrigerant has the property of sinking downward in the direction of gravity in air.

Specific examples of such refrigerants include tetrafluoropropene (CF3CF=CH2:HFO-1234yf), difluoromethane (CH2F2:R32), propane (R290), propylene (R1270), ethane (R170), and butane (R600). ), isobutane (R600a), 1.1.1.2-tetrafluoroethane (C2H2F4:R134a), pentafluoroethane (C2HF5:R125), 1.3.3.3-tetrafluoro-1-propene (CF3- A (mixed) refrigerant consisting of one or more refrigerants selected from CH=CHF:HFO-1234ze), carbon dioxide (CO2:R744), etc. can be used.

The compressor 11 compresses the refrigerant to increase the pressure and temperature of the refrigerant. The compressed refrigerant is discharged from the compressor 11. As the compressor 11, for example, a rotary compressor, a scroll compressor, a reciprocating compressor, etc. can be used.

The condenser 12 exchanges heat between the refrigerant discharged from the compressor 11 and surrounding air, radiates heat from the refrigerant, and condenses the refrigerant. The condenser fan 15 sends out air heated by the condenser 12 and also sends new air around the condenser 12, thereby promoting heat exchange in the condenser 12.

The expansion valve 13 expands the refrigerant condensed in the condenser 12 and reduces the pressure of the refrigerant. In the configuration example described here, the expansion valve 13 is a linear electric expansion valve (LEV). Therefore, by closing the expansion valve 13, the flow of the refrigerant can be prevented.

The evaporator 14 exchanges heat between the refrigerant whose pressure has been reduced by the expansion valve 13 and the surrounding air, causing the refrigerant to absorb heat and evaporate it. At this time, the air that has exchanged heat with the refrigerant is cooled. That is, the evaporator 14 functions as a cooler. The evaporator fan 16 sends out air cooled by the evaporator 14 as a cooler, and also sends new air around the evaporator 14 to promote heat exchange in the evaporator 14.

By circulating the refrigerant through the refrigerant circuit configured as described above, a vapor compression refrigeration cycle is realized. The refrigeration cycle realized by this refrigerant circuit functions as a heat pump that transfers heat between the evaporator 14 side and the condenser 12 side. Note that the evaporator fan 16 and the condenser fan 15 are, for example, a propeller fan, a line flow fan (registered trademark), a sirocco fan, or the like.

Inside the machine room 2, a compressor 11, a condenser 12, a condenser fan 15, and an expansion valve 13 are housed. The machine room 2 has an air supply port 31 and an air exhaust port 32 formed therein. The air supply port 31 is an opening for introducing outside air into the machine room 2. The exhaust port 32 is an opening for exhausting the air that has passed through the condenser 12 to the outside of the machine room 2. In the configuration example described here, the air supply port 31 is arranged on the same side as the opening 5 of the storage chamber 3, that is, on the front surface of the housing 1. The exhaust port 32 is arranged on the opposite side of the air supply port 31, that is, on the back surface of the housing 1.

A machine room air passage is formed inside the machine room 2, leading from the air intake 31 to the exhaust 32. The condenser 12 and the condenser fan 15 are disposed in this machine room air passage. The condenser fan 15 is a fan that generates an air flow that passes through the condenser 12 in the machine room air passage.

A blowout port 22 and a suction port 21 are formed in the storage chamber 3 . The housing 1 is provided with a storage room air path extending from an inlet 21 to an outlet 22. This storage room air path is separated from the storage room 3. An evaporator 14 and an evaporator fan 16 are housed in the storage room air path. That is, the evaporator 14 is arranged in a storage room air path that communicates with the inside of the storage room 3 via the outlet 22 . The evaporator fan 16 then generates an air flow through the evaporator 14 into the storage air path.

When the evaporator fan 16 is driven, the cold air generated after passing through the evaporator 14 is blown out from the outlet 22 into the storage chamber 3 . The air outlet 22 opens downward at the front end of the upper inner wall surface of the storage chamber 3 so as to face the storage chamber 3 . The cool air blown out from the air outlet 22 descends along the opening surface of the opening 5. As a result, an air curtain of cold air is formed in the opening 5 of the storage chamber 3. A part of the air in the storage chamber 3 is sucked in through the suction port 21. The air sucked in from the suction port 21 is cooled by the evaporator 14 while passing through the storage room air path, and is blown out into the storage room 3 from the air outlet 22 again.

The showcase 100 is equipped with a heater 19. The heater 19 is for keeping the stored items in the storage chamber 3 warm. In the configuration example described here, the heater 19 is provided on the lower surface of each display shelf 4. When the heater 19 is energized, the heater 19 generates heat, heats the stored items placed on the display shelf 4, and can keep the stored items warm.

The showcase 100 of this embodiment includes a check valve 18. The check valve 18 is provided in the refrigerant pipe 17 between the evaporator 14 and the compressor 11. The check valve 18 allows refrigerant to flow in only one direction. In this embodiment, the refrigerant can flow only from the evaporator 14 to the compressor 11. That is, the check valve 18 allows the refrigerant to flow from the evaporator 14 to the compressor 11. Then, the check valve 18 prohibits the flow of refrigerant from the compressor 11 to the evaporator 14 . By providing such a check valve 18, even if the operation of the compressor 11 is stopped and the flow of refrigerant in the refrigerant circuit is stopped, refrigerant will not flow from the compressor 11 to the evaporator 14.

As described above, by closing the expansion valve 13, the flow of refrigerant can be prevented. That is, the expansion valve 13 constitutes a blocking means capable of blocking the flow of refrigerant. More specifically, in this embodiment, the expansion valve 13 also serves as a blocking means. An expansion valve 13 serving as a blocking means is provided in a refrigerant pipe 17 between the condenser 12 and the evaporator 14. Note that as a blocking means, a shutoff valve other than the expansion valve 13 may be provided in the refrigerant pipe 17 between the condenser 12 and the evaporator 14.

Next, the configuration of the control system of the showcase 100 of this embodiment will be described with reference to FIG. 2. As shown in the figure, the showcase 100 includes a control device 50. The control device 50 controls the overall operation of the showcase 100. Specifically, controller 50 controls the operation of compressor 11 , condenser fan 15 , evaporator fan 16 , and heater 19 . Furthermore, the control device 50 also controls the operation of the expansion valve 13 as the blocking means described above.

The showcase 100 is capable of normal refrigeration or freezing operation (hereinafter also simply referred to as "normal operation") and heat retention operation. The normal operation is an operation in which stored items in the storage chamber 3 are cooled. The heat retention operation is an operation in which stored items in the storage chamber 3 are heated and kept warm. During normal operation, the controller 50 opens the expansion valve 13 and operates the compressor 11, condenser fan 15, and evaporator fan 16. During normal operation, the control device 50 stops energizing the heater 19 .

On the other hand, when performing the heat retention operation, the control device 50 energizes the heater 19. In the heat retention operation, the control device 50 stops the operation of the compressor 11 and the evaporator fan 16. The condenser fan 15 may or may not operate during the heat retention operation.

Furthermore, the showcase 100 of this embodiment is capable of recovery operation in addition to the above normal operation and heat retention operation. The recovery operation is an operation in which the refrigerant in the refrigerant circuit is recovered to the machine room 2 side of the refrigerant circuit. In the recovery operation, the control device 50 first causes the above-mentioned blocking means to block the flow of the refrigerant. In the configuration example described here, the control device 50 closes the expansion valve 13. Then, the control device 50 operates the compressor 11. Thereby, the refrigerant on the evaporator 14 side of the storage chamber 3 is sucked out to the compressor 11.

The high temperature gas phase refrigerant discharged from the compressor 11 passes through the condenser 12 and undergoes heat exchange with air. This heat exchange causes the gas phase refrigerant to liquefy. The liquefied refrigerant passes through the condenser 12 and reaches the expansion valve 13. At this time, since the expansion valve 13 is closed, the liquid phase refrigerant is mainly contained in the refrigerant pipe 17 between the compressor 11 and the condenser 12 and between the condenser 12 and the expansion valve 13. It is collected in the pipe 17 and into the condenser 12.

The control device 50 stops the operation of the compressor 11 and ends the recovery operation when a preset reference time has elapsed since the start of the recovery operation. The reference time can be determined by taking into account the time required to move the refrigerant to the machine room 2 based on the specifications of the showcase 100, such as the amount of refrigerant filled in the refrigerant circuit and the capacity of the compressor 11.

As mentioned above, the check valve 18 is provided in the configuration example described here. Therefore, even if the compressor 11 is left stopped after the recovery operation ends, refrigerant does not flow back from the compressor 11 to the evaporator 14. Note that the compressor 11 is generally provided with a structure such as a valve to prevent backflow. Therefore, in such a case, the check valve 18 may be omitted. However, from the viewpoint of more reliably preventing the backflow of the refrigerant recovered to the machine room 2 side, it is desirable to provide the check valve 18.

When performing the heat retention operation, the showcase 100 of this embodiment starts the heat retention operation after performing the collection operation. That is, the control device 50 performs the recovery operation before starting the heat retention by the heater 19. After the recovery operation is completed, the control device 50 causes the heater 19 to start keeping warm.

As mentioned above, during normal operation of the showcase 100, the condenser fan 15 and the evaporator fan 16 are operating. Therefore, when refrigerant leaks from the refrigerant circuit, whether in the machine room 2 side or the storage room 3 side, the leaked refrigerant is diffused by stirring with the airflow by the condenser fan 15 or the evaporator fan 16. This makes it possible to suppress the formation of a region where leaked refrigerant stagnates and the refrigerant concentration exceeds a certain level.

On the other hand, when the showcase 100 is kept warm, the evaporator fan 16 is stopped as described above. For this reason, especially when refrigerant leaks from the refrigerant circuit on the side of the storage room 3, a region is likely to be formed where the leaked refrigerant is not diffused but remains and the refrigerant concentration exceeds a certain level. According to the showcase 100 of this embodiment, by starting the heat retention operation after performing the recovery operation, even if breakage, corrosion, etc. occur in the refrigerant circuit on the storage room 3 side during the heat retention operation, refrigerant leakage can be prevented. It is possible to suppress refrigerant leakage or minimize refrigerant leakage. Therefore, in the showcase 100 that stops the circulation of air in the storage room 3 during the heat retention operation, it is possible to reduce the amount of refrigerant leakage when the refrigerant leaks from the storage room 3 side of the refrigerant circuit during the heat retention operation. Therefore, it is possible to suppress the formation of a region where the leaked refrigerant stagnates and the refrigerant concentration exceeds a certain level. As mentioned above, the condenser fan 15 may or may not operate during the heat retention operation, but if the condenser fan 15 is operated during the heat retention operation, refrigerant will not leak from the refrigerant circuit on the machine room 2 side. When leaked refrigerant occurs, it is possible to diffuse the leaked refrigerant by agitating it with an air flow by the condenser fan 15.

Note that the control device 50 may operate one or both of the evaporator fan 16 and the condenser fan 15 during the recovery operation. By doing this, if refrigerant leaks from the refrigerant circuit during recovery operation, the leaked refrigerant can be diffused and the leaked refrigerant can be prevented from stagnation and the formation of an area where the refrigerant concentration exceeds a certain level. . Further, when operating the condenser fan 15 during the recovery operation, it is even better if the control device 50 operates the condenser fan 15 at a higher rotation speed during the recovery operation than during normal operation. By doing so, the heat exchange efficiency in the condenser 12 can be improved and liquefaction of the refrigerant can be promoted. Therefore, the time required for recovery operation can be shortened, and refrigerant recovery can be completed in a shorter time.

Next, an example of the collection operation and heat retention operation in the showcase 100 configured as described above will be described with reference to the flowchart of FIG. 3. When the showcase 100 in normal operation starts a recovery operation, first, in step S1, the control device 50 causes the condenser fan 15 and the evaporator fan 16 to continue operating as they are.

In the subsequent step S2, the control device 50 closes the expansion valve 13, which serves as the blocking means described above, to prevent the refrigerant from flowing in the location where the expansion valve 13 is provided. In the following step S3, the control device 50 operates the compressor 11. After step S3, the process proceeds to step S4.

In step S4, the control device 50 checks whether the above-mentioned reference time has elapsed since the start of the recovery operation. If the above-mentioned reference time has not elapsed since the start of the recovery operation, the process returns to step S3 and the compressor 11 continues to operate. Then, when the above-mentioned reference time has elapsed since the start of the recovery operation, the process proceeds from step S4 to step S5.

In step S5, the control device 50 stops the compressor 11. In the following step S6, the control device 50 stops the evaporator fan 16 and ends the recovery operation. The process then proceeds to step S7, where the control device 50 energizes the heater 19 to start the heat retention operation. When the process of step S7 is completed, the series of operations ends.

Next, a modification of the showcase 100 configured as described above will be described with reference to FIGS. 4 and 5. In the configuration examples described so far, the conditions for ending the recovery operation are determined based on the elapsed time from the start of the recovery operation. In the modification shown in FIGS. 4 and 5, the conditions for ending the collection operation are determined using the detection results of the sensors.

First, a modification shown in FIG. 4 will be described with reference to the same figure. In this modification, the showcase 100 includes a temperature sensor 41. Temperature sensor 41 is a sensor that detects the temperature of condenser 12. Note that the temperature of the condenser 12 here refers to the surface temperature of the condenser 12 or the temperature of the refrigerant flowing within the condenser 12. Then, when the temperature of the condenser 12 detected by the temperature sensor 41 becomes equal to or lower than a preset reference temperature after the start of the recovery operation, the control device 50 stops the compressor 11 and ends the recovery operation.

Next, a modification shown in FIG. 5 will be described with reference to the same figure. In this modification, the showcase 100 includes a pressure sensor 42. The pressure sensor 42 is provided in the refrigerant pipe 17 between the evaporator 14 and the check valve 18. Then, the pressure sensor 42 detects the pressure of the refrigerant in the refrigerant pipe 17 between the evaporator 14 and the check valve 18.

When the compressor 11 continues to operate during the recovery operation, the pressure on the suction side of the compressor 11 gradually decreases as the refrigerant is recovered. Therefore, the control device 50 controls the recovery operation when the pressure detected by the pressure sensor 42, that is, the pressure of the refrigerant in the refrigerant pipe 17 on the evaporator 14 side becomes equal to or lower than a preset reference pressure after the start of the recovery operation. Terminate operation. By setting the value of the reference pressure at which this recovery operation ends as low as possible, more refrigerant can be moved from the storage chamber 3 side to the machine room 2 side. Therefore, the value of the reference pressure at which the recovery operation ends is preferably the minimum pressure allowed for the operation of the compressor 11.

In addition, in the modification shown in FIG. 5, when restarting normal operation after the recovery operation, the control device 50 prohibits the restart of normal operation if the pressure detected by the pressure sensor 42 is higher than the above-mentioned reference pressure. You may also do so. As described above, at the end of the recovery operation, the pressure in the refrigerant pipe 17 on the evaporator 14 side should have been below the reference pressure. The fact that it became higher than the standard pressure when normal operation resumed means that the refrigerant circuit on the evaporator 14 side, that is, on the storage chamber 3 side, has broken or corroded, and outside air has entered the refrigerant pipe 17. There is a possibility that the pressure in the refrigerant pipe 17 has increased. Therefore, if the pressure detected by the pressure sensor 42 is higher than the above-mentioned reference pressure when normal operation is resumed, the control device 50 keeps the expansion valve 13 as the above-mentioned blocking means closed, and resumes normal operation. It is advisable to prohibit reopening.

In the configuration example described above, both the opening 5 of the storage chamber 3 and the air supply port 31 of the machine room 2 are arranged on the front surface of the housing 1. For this reason, refrigerant leakage occurred in the refrigerant circuit on the storage chamber 3 side during the heat retention operation when the evaporator fan 16 was stopped, and the leaked refrigerant leaked out from the opening 5 of the storage chamber 3 to the outside of the showcase 100. In this case, if the condenser fan 15 is operating, it can be said that the refrigerant leaking to the outside of the showcase 100 is easily sucked into the machine room 2 through the air supply port 31 and diffused.

However, as described above, according to the showcase 100 of this embodiment, since the refrigerant is recovered to the machine room 2 side during the heat retention operation, each of the air supply port 31 and the exhaust port 32 of the machine room 2 is may be placed on any one of the left side, right side, and back side of the housing 1. For example, FIG. 6 shows a case where the air supply port 31 and exhaust port 32 of the machine room 2 are arranged on the side surface of the housing 1. By doing so, the air supply port 31 and exhaust port 32 of the machine room 2 are not present on the front surface of the casing 1 where the opening 5 of the storage room 3 is located, so that the appearance of the showcase 100 can be improved in design. Further, on the side of the storage chamber 3 where the opening 5 is located, dust, foreign matter, etc. are likely to fly around when objects are put in and taken out of the storage chamber 3. By arranging the air supply port 31 and the exhaust port 32 of the machine room 2 on a side of the housing 1 that is different from the side where the opening 5 of the storage room 3 is located, as shown in the example of FIG. Intrusion into the machine room 2 through the air port 31 and the exhaust port 32 can be suppressed.

Note that instead of starting the heat retention operation after the recovery operation ends, the heat retention operation may be started after the recovery operation starts and before the recovery operation ends. That is, before starting heat retention by the heater 19, the control device 50 first prevents the flow of the refrigerant using the above-mentioned blocking means, operates the compressor 11 in a state where the flow of the refrigerant is blocked, and converts the refrigerant into a refrigerant. A recovery operation is performed to recover the machine room 2 side of the circuit. Then, the control device 50 may start keeping warm by the heater 19 during this recovery operation. Even in this case, the amount of refrigerant on the storage chamber 3 side of the refrigerant circuit can be reduced at the start of the heat retention operation compared to before the start of the recovery operation. Therefore, even if refrigerant leakage occurs on the storage chamber 3 side of the refrigerant circuit during the heat retention operation before the end of the recovery operation, a certain effect can be obtained in reducing the amount of refrigerant leakage.

Further, instead of starting the heat retention operation after the recovery operation ends, the heat retention operation may be started before the recovery operation starts. That is, the control device 50 first starts heat retention by the heater 19, then blocks the circulation of the refrigerant by the above-mentioned blocking means, and operates the compressor 11 in a state where the circulation of the refrigerant is blocked to remove the refrigerant. A recovery operation for recovering the refrigerant to the machine room 2 side of the refrigerant circuit is started. Even in this case, the amount of refrigerant on the storage chamber 3 side of the refrigerant circuit can be reduced during the heat retention operation compared to before the start of the recovery operation. Therefore, even if refrigerant leakage occurs on the storage chamber 3 side of the refrigerant circuit during the heat retention operation before the end of the recovery operation, a certain effect can be obtained in reducing the amount of refrigerant leakage. Furthermore, by starting energization of the heater 19 before the recovery operation, it is possible to obtain the heat retention effect of the storage chamber 3 at an early stage.

Furthermore, when a check valve 18 is provided in the refrigerant pipe 17 between the compressor 11 and the evaporator 14, the evaporator 14 is indirectly operated by the heater 19 without operating the compressor 11 during the recovery operation. The refrigerant on the storage chamber 3 side of the refrigerant circuit may be moved to the machine room 2 side of the refrigerant circuit using the heating effect. Next, an example of the operation of the showcase 100 in this case will be described with reference to the flowchart in FIG. 7. First, in step S11, the control device 50 causes the condenser fan 15 and the evaporator fan 16 to continue operating.

In the subsequent step S12, the control device 50 closes the expansion valve 13 as the above-mentioned blocking means to prevent the refrigerant from flowing in the location where the expansion valve 13 is provided. In the following step S13, the control device 50 stops the compressor 11. After step S13, the process proceeds to step S14.

In step S14, the control device 50 starts energizing the heater 19. By energizing the heater 19, the air within the storage chamber 3 is heated. Then, the evaporator fan 16 causes the warmed air in the storage chamber 3 to pass through the evaporator 14, thereby heating the evaporator 14. Then, the refrigerant in the evaporator 14 is heated and its pressure increases. Since the expansion valve 13 is closed in step S12, the refrigerant on the evaporator 14 side passes through the check valve 18 and flows to the compressor 11 side. The check valve 18 prevents refrigerant from flowing from the compressor 11 side to the evaporator 14 side. Therefore, the refrigerant moves from the storage room 3 side to the machine room 2 side of the refrigerant circuit.

In subsequent step S15, the control device 50 checks whether a preset time has elapsed since energization of the heater 19 was started in step S14. Then, when a preset time has elapsed since the start of energizing the heater 19, the process proceeds to step S16. In the following step S16, the control device 50 stops the evaporator fan 16, and the showcase 100 completely shifts to the heat retention operation. When the process of step S16 is completed, the series of operations ends.

Also in the operation example shown in FIG. 7, the amount of refrigerant on the storage chamber 3 side of the refrigerant circuit during the heat retention operation can be reduced compared to during normal operation. Therefore, a certain effect can be obtained in reducing the amount of refrigerant leakage when refrigerant leakage occurs on the storage chamber 3 side of the refrigerant circuit during the heat retention operation.

In each of the configuration examples of the showcase 100 described above, the expansion valve 13 may be a solenoid valve that closes when no electricity is applied. As a result, if refrigerant leaks on the storage room 3 side of the refrigerant circuit during a power outage, the refrigerant in the refrigerant circuit on the machine room 2 side than the expansion valve 13 and check valve 18 is prevented from leaking and evaporates. If breakage or corrosion occurs in the refrigerant 14, the entire amount of refrigerant in the refrigerant circuit will leak, but by installing a solenoid valve that closes when no electricity is applied, the amount of refrigerant that leaks can be reduced.

1 Housing 2 Machine room 3 Storage room 4 Display shelf 5 Opening 6 Heater 11 Compressor 12 Condenser 13 Expansion valve 14 Evaporator 15 Condenser fan 16 Evaporator fan 17 Refrigerant piping 18 Check valve 19 Heater 21 Suction port 22 Blower Outlet 31 Air supply port 32 Exhaust port 41 Temperature sensor 42 Pressure sensor 50 Control device 100 Showcase

Claims (7)

A refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order through refrigerant piping filled with refrigerant;
A heater for keeping stored items warm in the storage room,
A blocking means provided in the refrigerant pipe between the condenser and the evaporator and capable of blocking the flow of the refrigerant,
The evaporator is arranged in an air path communicating with the inside of the storage chamber via an outlet,
The compressor and the condenser are arranged in a machine room,
an evaporator fan disposed in the air path and generating airflow through the evaporator;
a condenser fan disposed within the machine room and generating airflow through the condenser;
further comprising a control device for controlling the compressor, the heater, the evaporator fan, the condenser fan, and the blocking means,
The storage room and the machine room are formed in one housing,
The opening of the storage chamber and the air supply port of the machine room are arranged on the same side of the housing,
The control device includes:
Before starting heat retention by the heater, performing a recovery operation in which the compressor is operated in a state where the flow of the refrigerant is blocked by the blocking means to recover the refrigerant to the machine room side of the refrigerant circuit; After the recovery operation, the compressor is stopped and heat retention by the heater is started,
During the recovery operation, the showcase stops the evaporator fan and operates the condenser fan at a rotational speed higher than that at which the refrigerant leaking in the refrigerant circuit can be diffused. The showcase according to claim 1, wherein the expansion valve also serves as the blocking means. Provided in the refrigerant pipe between the evaporator and the compressor, allowing the refrigerant to flow from the evaporator to the compressor, and allowing the refrigerant to flow from the compressor to the evaporator. The showcase according to claim 1 or claim 2, further comprising a check valve that prohibits. further comprising a pressure sensor that is installed in the refrigerant pipe between the evaporator and the check valve and detects the pressure of the refrigerant,
The control device terminates the recovery operation when the pressure of the refrigerant in the refrigerant pipe between the evaporator and the check valve becomes equal to or less than a preset reference pressure after the start of the recovery operation. 4. The showcase according to claim 3, wherein: When restarting normal operation after the recovery operation, if the pressure of the refrigerant in the refrigerant pipe between the evaporator and the check valve is higher than the reference pressure, the control device is configured to restart the normal operation. 5. The showcase according to claim 4, which prohibits resumption of operation. The showcase according to any one of claims 1 to 3, wherein the control device ends the recovery operation when a preset reference time has elapsed after starting the recovery operation. Further comprising a temperature sensor that detects the temperature of the condenser,
4. The control device according to claim 1, wherein the control device terminates the recovery operation when the temperature of the condenser becomes equal to or lower than a preset reference temperature after the start of the recovery operation. Showcase.

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