Internal refrigeration device and refrigeration storage

Abstract

This internal refrigeration device for cooling an internal space (S) comprises: a refrigerant circuit (R) for performing a refrigeration cycle; a refrigerant sensor (50) for detecting a refrigerant leaked in the internal space (S); a first sensor (51) for detecting an indicator different from the refrigerant; and a control unit (100) for determining leakage of the refrigerant in the internal space (S) on the basis of detection results of the refrigerant sensor (50) and the first sensor (51).

Description

In-fridge refrigeration equipment and refrigerated storage facilities

[0001] The present disclosure relates to an internal refrigeration device and a refrigerated storage cabinet.

[0002] The in-compartment refrigeration system disclosed in Patent Document 1 includes a refrigerant sensor provided inside the container, which detects refrigerant gas leaking from a refrigerant circuit into the container.

[0003] Japanese Patent Application Laid-Open No. 2020-101327

[0004] In a refrigerated storage container such as the container of Patent Document 1, if miscellaneous gases are generated in the interior space of the container, the refrigerant sensor may erroneously detect the miscellaneous gases as refrigerant gas.

[0005] An object of the present disclosure is to provide an in-compartment refrigeration device that suppresses false detection of refrigerant leaking inside the compartment.

[0006] The first aspect is an internal refrigeration device that cools an internal space (S) using a refrigerant circuit (R) that performs a refrigeration cycle, and includes a refrigerant sensor (50) for detecting refrigerant leaking in the internal space (S), a first sensor (51) that detects an indicator different from the refrigerant, and a control unit (100) that determines whether refrigerant is leaking in the internal space (S) based on the detection results of the refrigerant sensor (50) and the first sensor (51).

[0007] The refrigerant sensor (50) alone may erroneously detect, for example, miscellaneous gases generated in the internal space (S) as refrigerant gas. In contrast, in the first aspect, the detection result of the first sensor (51) is used in addition to the detection result of the refrigerant sensor (50) to determine whether or not a refrigerant leak has occurred. By determining that the change in the internal environment detected by the first sensor (51) is due to refrigerant gas, erroneous detection of a refrigerant leak in the internal space (S) can be suppressed.

[0008] In the second aspect, in the first aspect, the first sensor (51) detects a gas component in the internal space (S), and the control unit (100) determines the occurrence of refrigerant leakage in the internal space (S) when the refrigerant sensor (50) detects a refrigerant leakage and the first sensor (51) detects that the concentration of the gas component in the internal space (S) or the degree of change in the concentration is outside a predetermined range.

[0009] In the second aspect, the first sensor (51) can be used to detect the gas components in the internal space (S) as well as to determine whether or not there is a refrigerant leak.

[0010] A third aspect is the second aspect, wherein the first sensor (51) detects humidity, oxygen or carbon dioxide in the interior space (S).

[0011] In the third aspect, a sensor of a type used to detect humidity, oxygen, or carbon dioxide is unlikely to mistakenly detect a miscellaneous gas such as ethylene gas. By using such a sensor and the refrigerant sensor (50) to determine whether or not there is a refrigerant leak, the reliability of the determination of whether or not there is a refrigerant leak can be improved. In addition, such a sensor is already installed in the internal space (S), so there is no need to install a new sensor.

[0012] In a fourth aspect, in the first aspect, the first sensor (51) detects the pressure of the gas in the internal space (S), and the control unit (100) determines the presence of a refrigerant leakage in the internal space (S) when the refrigerant sensor (50) detects a refrigerant leakage and the first sensor (51) detects that the pressure of the gas in the internal space (S) or the degree of change in the pressure is outside a predetermined range.

[0013] In the fourth aspect, when refrigerant leaks, the pressure of the gas in the internal space (S) increases, and this change in the pressure of the gas in the internal space (S) can be used to determine whether refrigerant is leaking.

[0014] A fifth aspect is the first aspect, further comprising an internal fan (30) for circulating air in the internal space (S), wherein the first sensor (51) detects a current value of a motor (30a) for driving the internal fan (30), and the control unit (100) determines the occurrence of refrigerant leakage in the internal space (S) when the first sensor (51) detects that a refrigerant leakage has occurred and the first sensor (51) detects that the current value of the motor (30a) or the degree of change in the current value is outside a predetermined range.

[0015] In the fifth aspect, when refrigerant leaks into the internal space (S), the density of the gas composition in the internal space (S) increases. This increases the operating load of the internal fan (30), and the value of the current flowing through the motor (30a) increases. This change in the current value can be used to determine whether refrigerant is leaking.

[0016] In a sixth aspect, in the first aspect, the first sensor (51) detects the pressure or temperature of the refrigerant flowing through the refrigerant circuit (R), and the control unit (100) determines the occurrence of refrigerant leakage in the internal space (S) when the first sensor (51) detects a refrigerant leakage and when the first sensor (51) detects that an index indicating the pressure or temperature of the refrigerant flowing through the refrigerant circuit (R) or a degree of change in the index is outside a predetermined range.

[0017] In the sixth aspect, when refrigerant leaks from the refrigerant circuit (R), the pressure and temperature of the refrigerant in the refrigerant circuit (R) change. This change in the refrigerant pressure or refrigerant temperature in the refrigerant circuit (R) can be used to determine whether refrigerant is leaking.

[0018] A seventh aspect is a refrigerated storage cabinet equipped with the internal refrigeration device of any one of the first to sixth aspects.

[0019] Fig. 1 is a perspective view of an internal refrigeration unit according to an embodiment, as seen from the front. Fig. 2 is a vertical cross-sectional view of the internal refrigeration unit. Fig. 3 is a piping diagram of the internal refrigeration unit. Fig. 4 is a block diagram showing the relationship between a control unit of the internal refrigeration unit and other devices. Fig. 5 is a flowchart showing the operation of the control unit to determine refrigerant leakage. Fig. 6 is a table showing an example of the relationship between the amount of refrigerant leakage and relative humidity. Fig. 7 is a flowchart showing the operation of the control unit to determine refrigerant leakage according to Modification 4.

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. Furthermore, each configuration of the embodiments, modifications, other examples, etc. described below can be combined or partially substituted within the scope of the present invention.

[0021] (1) Overall Configuration of Container As shown in FIG. 1, the internal refrigeration system (10) is applied to a container (1). The container (1) is an example of a refrigerated storage facility (1). The container (1) is used for marine transportation. The container (1) is a refrigerated container that cools the air inside it.

[0022] The overall configuration of the container (1) of this embodiment will be described with reference to Figures 1 to 3. In the following description, terms such as "front," "rear," "left," "right," "upper," and "lower" are based on the directions indicated by the arrows in Figure 1.

[0023] The container (1) has a container body (2) and an internal refrigeration unit (10). The internal space (S) of the container body (2) is partitioned into a storage space (3) and an air passage (19). The storage space (3) and the air passage (19) communicate with each other so that air circulates between them. Food, plants, and other stored items are stored in the storage space (3). The internal refrigeration unit (10) cools the air in the storage space (3). A front opening (4) is formed in the front of the container body (2). The internal refrigeration unit (10) is attached to the container body (2) so as to close the front opening (4) of the container body (2).

[0024] (2) In-compartment Refrigeration Device The in-compartment refrigeration device (10) has a casing (11). The casing (11) forms a lid for the front opening (4) of the container body (2). The casing (11) has a casing body (12) and a partition plate (13). The casing body (12) separates the storage space (3) from an external space (5) that is the external space of the container body (2). The partition plate (13) is located on the back side (rear side) of the casing (11).

[0025] The internal refrigeration system (10) includes a refrigerant circuit (R) that performs a refrigeration cycle. The internal refrigeration system (10) includes, as components arranged outside the refrigeration system, a compressor (25), an external heat exchanger (26), and an external fan (27). The internal refrigeration system (10) also includes, as components arranged inside the refrigeration system, an internal heat exchanger (29) and an internal fan (30).

[0026] (2-1) Casing Body As shown in FIG. 2, the casing body (12) has a flat plate portion (12a) and a recessed portion (12b). The flat plate portion (12a) is formed on the upper part of the casing body (12) so as to be substantially flush with the front opening (4) of the casing (11). As shown in FIG. 1, the flat plate portion (12a) is provided with an inspection window (22) and a ventilation device (40). The inspection window (22) is located on the right side of the flat plate portion (12a). The ventilation device (40) is located on the left side of the flat plate portion (12a). The inspection window (22) is a transparent window through which the interior of the casing body (12) can be seen. The ventilation device (40) ventilates the storage space (3).

[0027] The recess (12b) is formed in the lower part of the casing (11). The recess (12b) is recessed rearward from the lower end of the flat plate portion (12a). An external storage space (14) is formed in front of the recess (12b). An internal storage space (15) is formed above the recess (12b) and between the flat plate portion (12a) and the partition plate (13). The lower end of the recess (12b) forms a bottom plate (12c). The bottom plate (12c) extends to both the left and right ends of the casing body (12).

[0028] The casing body (12) is formed by stacking an external casing (16), a heat insulating layer (17), and an internal casing (18) in the thickness direction (front-rear direction). The external casing (16) faces the external space (5). The internal casing (18) faces the interior of the refrigerator. As described above, the recess (12b) has a side wall (16a) of the external casing (16) and a side wall of the internal casing (18) that extend in the vertical direction. The side wall (16a) of the external casing (16) that extends in the vertical direction separates the external space (5) from the air passage (19). The heat insulating layer (17) is provided between the external casing (16) and the internal casing (18). The external casing (16) is made of aluminum. The internal casing (18) is made of fiber-reinforced plastic (FRP). The heat insulating layer (17) is made of foamed resin.

[0029] (2-2) Partition Plate and Air Passage As shown in FIG. 2, the partition plate (13) is a plate-like member located behind the recess (12b). The partition plate (13) extends in the vertical direction so as to be spaced a predetermined distance from the rear surface of the recess (12b). An air passage (19) through which air flows inside the container is formed between the casing body (12) and the partition plate (13). An inlet (20) is formed between the upper end of the partition plate (13) and the upper wall (2a) of the container body (2). The inlet (20) connects the storage space (3) to the inlet end of the air passage (19). An outlet (21) is formed between the lower end of the partition plate (13) and the lower wall (2b) of the container body (2). The outlet (21) connects the storage space (3) to the outlet end of the air passage (19). Air flows in the vertical direction through the air passage (19). Specifically, air flows vertically through the air passage (19).

[0030] (2-3) Components of the External Space The external storage space (14) is provided with a compressor (25), an external heat exchanger (26), and an external fan (27). The compressor (25) is installed on the bottom plate (12c) of the casing (11). The compressor (25) is disposed near the bottom of the external storage space (14). The compressor (25) is disposed near the right of the external storage space (14).

[0031] The external fan (27) is located near the upper part of the external storage space (14). The external fan (27) is driven by an external fan motor (27a). The external fan (27) is a propeller fan. As shown in Figure 2, an external passage (28) through which external air flows is formed behind the external fan (27).

[0032] The external heat exchanger (26) is provided in the external storage space (14) at a height position between the external fan (27) and the compressor (25). The external heat exchanger (26) is located in the external passage (28). The external heat exchanger (26) is a fin-and-tube type heat exchanger.

[0033] (2-4) Components of the Internal Space An internal heat exchanger (29) and an internal fan (30) are provided in the air passage (19). The internal heat exchanger (29) and the internal fan (30) are provided in the internal storage space (15), which is part of the air passage (19). The internal heat exchanger (29) is supported by the casing (11) so as to span the casing body (12) and the partition plate (13). The internal heat exchanger (29) is a fin-and-tube heat exchanger.

[0034] The internal fan (30) circulates the air in the internal space (S). The internal fan (30) circulates the air in the internal space (S) between the storage space (3) and the air passage (19). The internal fan (30) is driven by an internal fan motor (30a). The internal fan (30) is a propeller fan.

[0035] (2-5) Refrigerant Circuit As shown in Fig. 3, the internal refrigeration unit (10) has a refrigerant circuit (R). The refrigerant circuit (R) is filled with a refrigerant. The refrigerant circuit (R) performs a vapor compression refrigeration cycle by circulating the refrigerant.

[0036] The refrigerant used in this embodiment is 2,3,3,3 tetrafluoropropene (hereinafter sometimes referred to as R1234yf refrigerant or R1234yf). The refrigerant may be difluoromethane (R32) or 1,3,3,3 tetrafluoropropene (R1234ze). The refrigerant may be a single refrigerant or a mixed refrigerant containing other refrigerants. The mixed refrigerant may be a refrigerant consisting of 2,3,3,3 tetrafluoropropene (R1234yf) and difluoromethane (R32). The mixed refrigerant may be a refrigerant (R454C) consisting of 78.5 wt% 2,3,3,3 tetrafluoropropene (R1234yf) and 21.5 wt% difluoromethane (R32). The refrigerant may be a flammable refrigerant. The flammable refrigerant may be a highly flammable natural refrigerant such as propane (R290), methane (R50), ethane (R170), butane (R600), or isobutane (R600a). The refrigerant may also be a natural refrigerant such as carbon dioxide (CO ２ ) may also be used.

[0037] The refrigerant circuit (R) mainly includes a compressor (25), an external heat exchanger (26), an expansion valve (31), and an internal heat exchanger (29).

[0038] The compressor (25) compresses the sucked refrigerant. The compressor (25) discharges the compressed refrigerant. A discharge pipe (32) is connected to a discharge portion of the compressor (25). A suction pipe (33) is connected to a suction portion of the compressor (25). An accumulator (34) is provided in the suction pipe (33). The accumulator (34) is a container for storing liquid refrigerant.

[0039] The external heat exchanger (26) exchanges heat between the refrigerant flowing therethrough and the external air. The gas end of the external heat exchanger (26) communicates with the discharge pipe (32). The liquid end of the external heat exchanger (26) is connected to the liquid end of the internal heat exchanger (29) via a liquid pipe (35). The external heat exchanger (26) functions as a radiator (condenser) that radiates heat from the refrigerant to the air.

[0040] The expansion valve (31) is provided in the liquid pipe (35). The expansion valve (31) reduces the pressure of high-pressure refrigerant to low-pressure refrigerant. The expansion valve (31) is an electronic expansion valve with an adjustable opening. A receiver (36) is provided in the liquid pipe (35) between the external heat exchanger (26) and the expansion valve (31). The receiver (36) is a container for storing excess refrigerant in the refrigerant circuit (R).

[0041] The internal heat exchanger (29) exchanges heat between the refrigerant flowing therethrough and the internal air. The gas end of the internal heat exchanger (29) communicates with the suction pipe (33). The internal heat exchanger (29) functions as an evaporator in which the refrigerant absorbs heat from the air.

[0042] The refrigerant circuit (R) has a bypass pipe (37). An inflow end of the bypass pipe (37) communicates with the discharge pipe (32), and an outflow end of the bypass pipe (37) communicates with the liquid pipe (35). The bypass pipe (37) sends the refrigerant discharged from the compressor (25) to the internal heat exchanger (29), bypassing the external heat exchanger (26).

[0043] The refrigerant circuit (R) is provided with a first valve (38) and a second valve (39). The first valve (38) is provided between the discharge side of the compressor (25) and the gas end of the external heat exchanger (26), and downstream of the connection portion of the bypass pipe (37). The second valve (39) is provided in the bypass pipe (37). The first valve (38) and the second valve (39) are formed by solenoid on-off valves. The first valve (38) and the second valve (39) may be flow control valves whose opening degrees are adjustable.

[0044] (2-6) Operation The internal refrigeration system (10) performs a cooling operation and a defrosting operation.

[0045] During cooling operation, a refrigeration cycle is performed in which refrigerant compressed by the compressor (25) is condensed in the external heat exchanger (26), reduced in pressure by the expansion valve (31), and evaporated in the internal heat exchanger (29). Air flowing out from the storage space (3) into the air passage (19) is cooled by the internal heat exchanger (29) functioning as an evaporator. The cooled air is sent to the storage space (3) (see the arrow in Figure 2).

[0046] During the defrosting operation, the refrigerant compressed by the compressor (25) flows through the bypass pipe (37) and then through the internal heat exchanger (29). The frost on the surface of the internal heat exchanger (29) melts due to the heat of the refrigerant flowing inside the internal heat exchanger (29).

[0047] (3) Control Unit As shown in Fig. 4, the internal refrigeration device (10) includes a control unit (100). The control unit (100) controls the internal refrigeration device (10). The control unit (100) includes a microprocessor, an electric circuit, and an electronic circuit. The microprocessor includes a CPU (Central Processing Unit), a memory, a communication interface, an analog input / output, and a contact input / output interface. The memory stores various programs to be executed by the CPU and data used by the programs.

[0048] The control unit (100) controls the mechanical elements of the internal refrigeration unit (10). As shown in FIG. 4, the target value may be a value that can be arbitrarily set by a user of the internal refrigeration unit (10) via an operation unit (101). The operation unit (101) is configured, for example, with a touch panel, a remote controller, or a dip switch provided on the internal refrigeration unit (10). The operation unit (101) may be a communication terminal connected to the internal refrigeration unit (10) via a network. The target value does not necessarily have to be set by a user, and may be a value that is automatically determined by the control unit (100) depending on, for example, the operation mode or the operating conditions.

[0049] (4) Refrigerant Sensor As shown in FIGS. 2 and 4, the in-compartment refrigeration system (10) includes a refrigerant sensor (50). The refrigerant sensor (50) detects refrigerant leaked from the refrigerant circuit (R) inside the container (1). Specifically, the refrigerant sensor (50) detects refrigerant contained in the air flowing through the air passage (19) as an indicator. The refrigerant sensor (50) is disposed below the in-compartment fan (30). Hereinafter, the air containing leaked refrigerant and the air not containing leaked refrigerant may be collectively referred to as air. The refrigerant sensor (50) will be described in detail below.

[0050] (5) Notification Device As shown in Fig. 4, the internal refrigeration device (10) includes a notification unit (60). The notification unit (60) notifies a user of predetermined information. The notification unit (60) includes a predetermined speaker or display. For example, when the control unit (100) determines that there is an abnormality in the internal refrigeration device (10) or the internal space (S), the notification unit (60) issues a notification from a speaker or displays an indication of the abnormality on a display.

[0051] (6) Issue of Refrigerant Sensor False Detection When the refrigerant (refrigerant gas) leaked into the internal space (S) and contained in the air flowing therein has similar properties to miscellaneous gases generated in the internal space (S), the refrigerant sensor (50) may detect the miscellaneous gases as refrigerant gas. For example, NDIR (Non-Dispersive InfraRed) sensors detect specific gases by utilizing the fact that various gases absorb specific wavelengths in the infrared range. With this NDIR refrigerant sensor, when the absorption wavelength range of the refrigerant gas and the absorption wavelength range of the miscellaneous gas overlap or are relatively close to each other, the refrigerant sensor cannot distinguish between the refrigerant gas and the miscellaneous gas, and may detect the miscellaneous gas as refrigerant gas.

[0052] Specifically, if R1234yf or R32 is used as the refrigerant in a refrigerator and fruit that generates ethylene gas is stored in the refrigerator, the refrigerant has an absorption wavelength peak around 3.3 μm, and ethylene gas also has an absorption wavelength peak around that same wavelength. Therefore, with this combination of gases, an NDIR refrigerant sensor may not be able to distinguish between the ethylene gas generated by the fruit and the refrigerant gas that has leaked into the refrigerator.

[0053] In contrast, the internal refrigeration system (10) of this embodiment includes a first sensor (51) that detects an indicator different from the refrigerant. In other words, the first sensor (51) does not detect refrigerant leaking into the internal space (S), which is the indicator detected by the refrigerant sensor (50). The internal refrigeration system (10) of this embodiment determines refrigerant leakage in the internal space (S) based on the detection results of the refrigerant sensor (50) and the first sensor (51). The first sensor (51) will be described in detail below.

[0054] In this embodiment, the indicator that differs from the refrigerant is a gas component in the internal space (S) other than the refrigerant. The first sensor (51) in this embodiment detects water vapor, which is a gas component in the internal space (S). The first sensor (51) is a humidity sensor (51) that detects the humidity in the internal space (S). The humidity may be either relative humidity or absolute humidity.

[0055] The humidity sensor (51) is arranged in the internal space (S). The humidity sensor (51) is arranged above the internal fan (30). The humidity sensor (51) is arranged on the air intake side of the internal fan (30).

[0056] The humidity sensor (51) of this embodiment is of the NDIR type. The absorption wavelength peak of water molecules is around 2.7 μm, and therefore the infrared absorption wavelength region of water molecules is different from the infrared absorption wavelength region of the refrigerant (e.g., R1234yf or R32). Therefore, the NDIR type humidity sensor (51) can suppress erroneous detection of miscellaneous gases and water molecules.

[0057] For example, if the humidity sensor (51) detects a behavior different from a normally expected change in humidity, such as a sudden drop in humidity in the interior space, it can be assumed that this is not due to humidity but due to refrigerant leaking into the interior space (S). In this way, the internal refrigeration system (10) of the present embodiment utilizes the humidity sensor (51), which is less likely to erroneously detect other miscellaneous gases, to prevent erroneous detection of the refrigerant by the refrigerant sensor (50).

[0058] (7) Operation of the Control Unit The operation of the control unit (100) for detecting refrigerant gas will now be described with reference to Fig. 5. The control unit (100) determines whether or not there is a refrigerant leak in the internal space (S) based on the detection results of the refrigerant sensor (50) and the humidity sensor (51). R1234yf is used as the refrigerant.

[0059] In step S11, the control unit (100) determines whether or not the refrigerant sensor (50) has detected refrigerant gas. Specifically, the control unit (100) determines whether or not a signal indicating that refrigerant gas has been detected has been received from the refrigerant sensor (50). If it is determined that the refrigerant sensor (50) has detected refrigerant gas (YES in step S11), step S12 is executed. If it is determined that the refrigerant sensor (50) has not detected refrigerant gas (NO in step S11), step S11 is executed again.

[0060] In step S12, the control section (100) determines whether or not the humidity sensor (51) has detected that the degree of change in humidity is outside a predetermined range. Here, the degree of change in humidity refers to the degree of decrease in humidity ΔRH in the internal space (S) during a certain period ΔT. For example, the predetermined period ΔT is set to one minute, and the range of humidity change (decrease) that is normally expected in the absence of refrigerant leakage into the internal space (S) during this one minute is set to the predetermined range ΔRH. ０ The humidity decrease (ΔRH) in the interior space (S) in one minute is within the specified range ΔRH ０ If the humidity sensor (51) detects that the humidity exceeds ΔRH, it can be inferred that the refrigerant gas has leaked into the compartment space (S). For example, ΔRH is the relative humidity RH of a certain period of time ago (for example, one minute ago). １ and the current relative humidity RH ２ (RH ２ <RH １ ) shows the difference.

[0061] The degree of change in humidity in the interior space (S) may be calculated by a predetermined calculation. For example, the degree of change in humidity can be calculated using Boyle's law. If the air temperature in the interior space (S) is 25°C and the relative humidity is 50%, the volume V corresponding to the amount of refrigerant leakage (kg) is calculated as follows: Ｒ (m ３ ), the volume V of the storage space (3) (m ３ ), the saturated water vapor amount RH in the storage space (3) at an air temperature of 25°C ｓ (g / m ３ ) and the amount of water vapor RH in the storage space (3) at an air temperature of 25°C ２５ (g / m ３) In this case, the humidity RH when the refrigerant leaks into the interior space (S) is RH = RH ２５ / RH Ｓ × V / (V + V Ｒ ) (Equation 1) holds. Based on Equation 1, ΔRH in a certain period ΔT can be calculated.

[0062] The fixed period ΔT is set arbitrarily. The fixed period ΔT may be set based on the items stored in the storage space (S), or may be set based on the region where the container is installed, the season, and the container's transportation route. Based on the premise that humidity changes are normally expected to be relatively gradual, the shorter the fixed period ΔT, the easier it is to distinguish between changes due to humidity and changes due to leaked refrigerant.

[0063] The degree of change in humidity ΔRH in the interior space (S) is within a specified range ΔRH ０ If it is determined that the humidity has exceeded the predetermined range ΔRH (YES in step S12), step S13 is executed. ０ If it is not determined that the leakage current has exceeded the predetermined value (NO in step S12), it is assumed that the refrigerant gas has not leaked into the interior space (S), and step S11 is executed again.

[0064] In step S13, the control section (100) determines that refrigerant has leaked into the internal space (S), and outputs to the notification section (60) a message indicating that refrigerant gas has leaked into the internal space (S).

[0065] In step S14, the control section (100) notifies the user of the fact that refrigerant gas is leaking by the notification section (60) through an alarm or a display.

[0066] In this embodiment, the amount of refrigerant leaking into the internal space (S) can be estimated based on the degree of change in humidity in the internal space (S). As shown in Fig. 6, when the amount of refrigerant charged in the internal refrigeration device (10) is approximately 6 kg, the relative humidity of the internal space (S) is calculated as X when the leakage amount is 1 kg (17% of the refrigerant charge amount), 3 kg (51% of the refrigerant charge amount), and 6 kg (100% of the refrigerant charge amount). １ %, Y１ %, Z １ % (50% > X １ >Y ２ >Z １ ). The humidity change in the storage space (S) over a certain period of time is 50% to X １ %, it can be assumed that 1 kg of refrigerant has leaked into the storage space (S). If the humidity in the storage space (S) changes from 50% to Y １ If the humidity in the interior space (S) changes from 50% to Z, it can be assumed that 3 kg of refrigerant has leaked into the interior space (S). １ %, it can be estimated that 6 kg of refrigerant has leaked into the interior space (S).

[0067] (8) Features (8-1) Feature 1 The internal refrigeration device (10) of this embodiment includes a refrigerant sensor (50) for detecting refrigerant leaking in the internal space (S) of the container (1), a first sensor (51) for detecting an indicator different from the refrigerant, and a control unit (100) for determining whether refrigerant is leaking in the internal space (S) based on the detection results of the refrigerant sensor (50) and the first sensor (51).

[0068] The refrigerant sensor (50) may detect miscellaneous gases such as ethylene gas that may be generated in the internal space (S). In this embodiment, the detection result of the first sensor (51) is used in addition to the detection result of the refrigerant sensor (50) to determine whether or not a refrigerant leak has occurred. As a result, if the refrigerant sensor (50) detects a refrigerant and the change in the internal space (S) environment detected by the first sensor (51) is due to a refrigerant leak, it can be determined that a refrigerant leak has occurred in the internal space (S). In this way, false detection of a refrigerant leak can be suppressed and the accuracy of refrigerant leak detection can be improved.

[0069] (8-2) Feature 2 The control unit (100) of the internal refrigeration system (10) of this embodiment determines the occurrence of refrigerant leakage in the internal space (S) when the refrigerant sensor (50) detects refrigerant leakage and the first sensor (51) detects that the degree of change in the concentration of the gas component in the internal space (S) is outside a predetermined range. This allows the first sensor (51) to be used not only for detecting the gas component in the internal space (S) but also for determining the occurrence of refrigerant leakage.

[0070] (8-3) Feature 3 The first sensor (51) of the internal refrigeration device (10) of this embodiment is a humidity sensor that detects the humidity in the internal space (S). The humidity sensor (51) detects water vapor (water molecules) and is less likely to detect other miscellaneous gases. By using the humidity sensor (51) to determine whether or not there is a refrigerant leak, the accuracy of the determination can be improved. Furthermore, the humidity sensor (51) is used to maintain the freshness (humidity control) of the items stored in the storage space (3) of the container (1). By using the humidity sensor (51) to determine whether or not there is a refrigerant leak, it is not necessary to provide a new sensor just for the purpose of determining whether or not there is a refrigerant leak, and the number of parts can be reduced.

[0071] (9) Modifications Modifications of the above embodiment will be described below, which are different from the above embodiment.

[0072] (9-1) Modification 1 The indicator that differs from the refrigerant indicator of Modification 1 is the pressure of the gas in the internal space (S). That is, the first sensor (51) of Modification 1 is a pressure sensor that detects the pressure of the gas in the internal space (S). When refrigerant gas leaks into the internal space (S), the pressure of the gas in the internal space (S) increases by the amount of the leaked refrigerant gas. Using this fact, the control unit (100) of Modification 1 determines whether refrigerant is leaking from the internal space (S) based on the detection results of the refrigerant sensor (50) and the pressure sensor.

[0073] Specifically, the control unit (100) of Modification 1 determines that refrigerant leakage has occurred in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage has occurred and the pressure sensor detects that the degree of change in the gas pressure in the internal space (S) is outside a predetermined range. Hereinafter, the pressure of the air in the internal space (S) may be referred to as the internal pressure.

[0074] The degree of change in the internal pressure indicates the degree of pressure increase of the gas in the internal space (S) in a certain period ΔT. For example, if the certain period ΔT is one minute, the range of the internal pressure that is normally assumed to decrease if no refrigerant leaks into the internal space (S) during this one minute is defined as the predetermined range ΔP. ０ The degree of increase ΔP in the internal pressure of the internal space (S) in one minute is within a predetermined range ΔP ０ If the pressure sensor detects that the pressure exceeds this, it is assumed that refrigerant gas has leaked into the internal space (S). For example, ΔP indicates the difference between the internal pressure P1 from a certain period of time ago (for example, one minute ago) and the current internal pressure P2 (P2 > P1).

[0075] The degree of change in the internal pressure may be calculated by a predetermined calculation. For example, the Boyle-Charles law can be used to calculate the degree of change in the internal pressure. Specifically, the internal pressure P1 due to the refrigerant leakage, the internal space volume V1, the standard atmospheric pressure P2 (1 atmosphere), and the volume V of the leaked refrigerant are used as the internal pressure P1. Ｒ Regarding P1=(V1+V Ｒ )×P2 / V1 (Equation 2) holds.

[0076] By substituting known values ​​for V1 and P2 in Equation 2, the volume of the refrigerant leak V Ｒ In this manner, in the first modification, the control section (100) determines whether the degree of change ΔP in the internal pressure during a certain period ΔT falls within a predetermined range ΔP ０ This determination operation by the control section (100) corresponds to step S12 in the above embodiment.

[0077] In the first modification, a pressure sensor in the internal space (S) can be used to determine refrigerant leakage. Also, the amount of refrigerant leaking into the internal space (S) can be estimated based on the degree of change in the internal pressure. For example, assuming that the amount of refrigerant charged in the internal refrigeration device (10) is approximately 6 kg, the pressures of the internal space (S) when the leakage amount is 1 kg (17% of the refrigerant charge amount), 3 kg (51% of the refrigerant charge amount), and 6 kg (100% of the refrigerant charge amount) are respectively expressed as X ２ kPa, Y ２ kPa, Z ２ kPa (P2<X ２ <Y ２ <Z ２ ). If the pressure inside the chamber changes from P2 to X within a certain period of time, ２ When the temperature rises to 100°C, it is clear that the amount of refrigerant leaked into the interior space (S) is 1 kg. ２ and Z ２ The same is true for .

[0078] (9-2) Modification 2 The indicator different from the refrigerant in Modification 2 is the current value of the motor (30a) that drives the internal fan (30). That is, the first sensor (51) in Modification 2 is a current sensor that detects the current value of the motor (30a) that drives the internal fan (30). When refrigerant leaks into the internal space (S), the density of the gas in the internal space (S) increases. This increases the operating load of the internal fan (30), and the current value flowing through the motor (30a) increases. Taking advantage of this, the control unit (100) in Modification 2 determines the presence of refrigerant leakage in the internal space (S) when the refrigerant sensor (50) detects refrigerant leakage and the current sensor detects that the degree of change in the current value of the motor (30a) is outside a predetermined range.

[0079] The degree of change in the current value indicates the degree of increase in the current value of the internal fan motor (30a) during a certain period ΔT. For example, the certain period ΔT is set to one minute, and the range within which the current value of the motor (30a) will increase, which is normally expected in the case where no refrigerant leaks into the internal space (S) during this one minute, is defined as a predetermined range ΔE ０ The increase (ΔE) in the current value of the motor (30a) of the interior space (S) in one minute is within a predetermined range ΔE０ If the current sensor detects that the current exceeds this, it is assumed that refrigerant gas has leaked into the compartment (S). For example, ΔE indicates the difference between the current value E1 from a certain period of time ago (for example, one minute ago) and the current current value E2 (E2 > E1).

[0080] In this way, the control section (100) determines whether the degree of change ΔE in the current value of the internal fan motor (30a) during a certain period ΔT is within a predetermined range ΔE ０ This determination operation by the control section (100) corresponds to step S12 in the above embodiment.

[0081] As described above, in the second modification, a current sensor that detects the current value of the internal fan motor (30a) can be used to determine whether refrigerant is leaking. The current value of the motor (30a) may be set based on the amount of refrigerant gas leaking into the internal space (S). This allows the amount of refrigerant that has leaked into the internal space (S) to be estimated by measuring the current value of the motor (30a).

[0082] (9-3) Modification 3 The indicator different from that of the refrigerant in Modification 3 is the pressure of the refrigerant flowing through the refrigerant circuit (R). That is, the first sensor (51) in Modification 3 is a refrigerant pressure sensor that detects the pressure of the refrigerant flowing through the refrigerant circuit (R). When refrigerant leaks from the refrigerant piping or the in-compartment heat exchanger (29), the pressure of the refrigerant in the refrigerant circuit (R) decreases. Taking advantage of this, the control unit (100) in Modification 3 determines the presence of a refrigerant leak in the in-compartment space (S) when the refrigerant sensor (50) detects a refrigerant leak and the refrigerant pressure sensor detects that the degree of change in the pressure of the refrigerant flowing through the refrigerant circuit (R) is outside a predetermined range. There is no particular limitation on the location of the refrigerant pressure sensor, but in Modification 3, the refrigerant pressure sensor is provided on the refrigerant piping in the refrigerant circuit (R).

[0083] The degree of change in refrigerant pressure indicates the degree of pressure drop of the refrigerant in the refrigerant circuit (R) in a certain period ΔT. For example, the certain period ΔT is set to one minute, and the range of the refrigerant pressure drop in the refrigerant circuit (R) that is assumed if no refrigerant leaks into the compartment space (S) in this one minute is defined as a predetermined range ΔP. Ｒ０ The degree of decrease in refrigerant pressure in the refrigerant circuit (R) in one minute is ΔP Ｒ is within the predetermined range ΔPＲ０ If the pressure sensor detects that the pressure exceeds ΔP, it is assumed that the refrigerant gas has leaked into the interior space (S). Ｒ is the refrigerant pressure P Ｒ１ and the current refrigerant pressure P Ｒ２ (P Ｒ２ <P Ｒ１ ) indicates the difference.

[0084] In this way, the control section (100) calculates the degree of change ΔP of the refrigerant pressure in the refrigerant circuit (R) over a certain period ΔT. Ｒ is within the predetermined range ΔP Ｒ０ This determination operation by the control section (100) corresponds to step S12 in the above embodiment.

[0085] As described above, in Modification 3, the refrigerant pressure sensor can be used to determine refrigerant leakage in the internal space (S). The refrigerant pressure value in the refrigerant circuit (R) may be set based on the amount of refrigerant gas leaking into the internal space (S). This allows the amount of refrigerant leaking into the internal space (S) to be estimated by measuring the refrigerant pressure in the refrigerant circuit (R).

[0086] (9-4) Modification 4 The internal refrigeration device (10) of Modification 4 does not have a refrigerant sensor (50) but has a first sensor (51). That is, in Modification 4, refrigerant leaking into the internal space (S) is detected only by the first sensor (51). The first sensor (51) may be any of the sensors of the above embodiment and Modifications 1 to 3. The first sensor (51) of Modification 4 is a humidity sensor (51). In Modification 4, refrigerant leakage into the internal space (S) is detected only by the humidity sensor (51). The operation of the control unit (100) of Modification 4 will be described with reference to FIG. 7.

[0087] In step S21, the control section (100) determines whether the humidity sensor (51) detects that the degree of change in humidity ΔRH in the compartment space (S) is within a predetermined range ΔRH ０ It is determined whether the humidity in the storage space (S) is outside the predetermined range ΔRH. ０ If it is determined that the humidity has exceeded the predetermined range ΔRH (YES in step S21), step S22 is executed.０ If it is determined that the humidity does not exceed the predetermined range ΔRH (NO in step S21), step S21 is executed again. ０ is as explained in the above embodiment.

[0088] In step S22, the control section (100) outputs to the notification section (60) a signal indicating that refrigerant gas is leaking into the internal space (S).

[0089] In step S23, the control section (100) notifies the user of the fact that refrigerant gas is leaking by the notification section (60) through an alarm or a display.

[0090] As described above, the humidity sensor (51) has a wavelength range in the infrared region where the absorption wavelengths of miscellaneous gases such as ethylene gas are different from that of water molecules, and therefore, erroneous detection of water molecules and miscellaneous gases can be suppressed. Therefore, refrigerant leaking into the compartment space (S) can be detected by using the humidity sensor (51) without using the refrigerant sensor (50). This allows the humidity sensor (51) to be used both to measure the humidity of the compartment space (S) and to detect leaking refrigerant.

[0091] (10) Other Embodiments The above-described embodiment or each of the above-described modifications may be configured as follows.

[0092] The container (1) may be used for land transport as well as for sea transport. The refrigerated storage (1) does not have to be a container. The refrigerated storage (1) may be a stationary refrigerated warehouse installed on land.

[0093] The sensor type of the first sensor (51) is not particularly limited. The first sensor (51) may be an NDIR type, a semiconductor type, or a thermal conductivity type. It is preferable that the first sensor (51) is not a sensor that causes false detection (cross-sensitivity) with miscellaneous gases (ethylene gas, etc.) other than the refrigerant gas that may be generated in the compartment space (S).

[0094] In the first modification, the first sensor (51) for detecting a gas component may be an ethylene gas sensor for detecting ethylene gas. In this case, the first sensor (51) need not be an NDIR sensor, and the refrigerant filled in the internal refrigeration device (10) need not be a refrigerant having a —CH group in its molecular structure (e.g., R32 or R1234yf). This is because, since ethylene also has a —CH group, an NDIR sensor would have overlapping absorption wavelength ranges between ethylene gas and refrigerant gas (e.g., R32 or R1234yf), which have the same —CH group, making it difficult to distinguish between the two and thus preventing improved refrigerant gas detection accuracy. For example, if the stored items stored in the storage space (3) are fruits and vegetables that generate ethylene gas, such as bananas, the ethylene gas sensor is used to monitor the ripening state of the fruits and vegetables. By using the ethylene gas sensor to detect refrigerant leaks in this way, there is no need to install a separate sensor for detecting refrigerant leaks, thereby reducing the number of components.

[0095] In the first modification, the first sensor (51) may be an oxygen sensor that detects oxygen in the internal space (S). The oxygen sensor may be, for example, a semiconductor type. The oxygen concentration in the internal space (S) decreases depending on the amount of refrigerant leaked into the internal space (S). Taking advantage of this, the control unit (100) determines whether refrigerant is leaking from the internal space (S) based on the detection results of the refrigerant sensor (50) and the oxygen sensor. In this case, too, the oxygen concentration (ppm) in the internal space (S) can be calculated based on the amount (kg) of refrigerant leaked into the internal space (S) using Boyle's law. This allows the determination of refrigerant leakage and the amount of refrigerant leakage based on the degree of decrease in the oxygen concentration in the internal space (S) or the oxygen concentration in the atmosphere. The oxygen sensor may be provided, for example, in a container (1) that includes an adjustment device (not shown) that adjusts the air composition in the internal space (S). The adjusting device adjusts the outside air to a predetermined composition and supplies the adjusted air to the storage space (S). The adjusting device adjusts the composition of the air in the storage space (3) to maintain the freshness of the stored items (especially fruits and vegetables) stored in the storage space (3). The oxygen sensor is used to detect whether the oxygen concentration in the storage space (3) has reached a target concentration by operating the adjusting device, and whether the oxygen concentration in the storage space (3) has returned to the atmospheric concentration after the adjusting device has stopped. By using such an oxygen sensor to detect refrigerant leaks, there is no need to install a new sensor to detect refrigerant leaks, and the number of parts can be reduced.

[0096] In the first modification, the first sensor (51) may be a carbon dioxide sensor that detects carbon dioxide in the internal space (S). The carbon dioxide sensor may be, for example, an NDIR type. The carbon dioxide concentration in the internal space (S) decreases depending on the amount of refrigerant leaked into the internal space (S). Taking advantage of this, the control unit (100) determines whether refrigerant is leaking in the internal space (S) based on the detection results of the refrigerant sensor (50) and the carbon dioxide sensor. In this case, too, the carbon dioxide concentration (ppm) in the internal space (S) can be calculated based on the amount (kg) of refrigerant leaked into the internal space (S) using Boyle's law. This allows for the determination of refrigerant leakage and the amount of refrigerant leakage based on the degree of decrease in the carbon dioxide concentration in the internal space (S) from the carbon dioxide concentration in the air or the atmospheric carbon dioxide concentration. The carbon dioxide sensor may be provided, for example, in the container (1) equipped with the above-described adjustment device. By using such a carbon dioxide sensor to also determine refrigerant leakage, it is not necessary to provide a separate sensor for determining refrigerant leakage, thereby reducing the number of components.

[0097] In the above embodiment, the control unit (100) may determine that refrigerant leakage has occurred in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage has occurred and the first sensor (51) detects that the gas concentration in the internal space (S) is outside a predetermined range. The predetermined range refers to a range that is normally expected for the gas concentration in the internal space (S) in the absence of refrigerant leakage. In other words, the control unit (100) may determine that refrigerant leakage has occurred in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage has occurred and the gas concentration in the internal space (S) exceeds the predetermined range.

[0098] In the first modification, the control unit (100) may determine that refrigerant leakage exists in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage exists and the first sensor (51) detects that the gas pressure in the internal space (S) is outside a predetermined range. The predetermined range indicates a range that is normally expected for the internal pressure of the internal space (S) in the absence of refrigerant leakage. In other words, the control unit (100) may determine that refrigerant leakage exists in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage exists and the air pressure in the internal space (S) exceeds the predetermined range.

[0099] In the second modification, the control unit (100) may determine that refrigerant leakage exists in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage exists and the first sensor (51) detects that the current value of the motor (30a) is outside a predetermined range. The predetermined range refers to a range of current values ​​that are normally expected for the motor (30a) when no refrigerant leakage exists. In other words, the control unit (100) may determine that refrigerant leakage exists in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage exists and the current value of the motor (30a) exceeds the predetermined range.

[0100] In the third modification, the control unit (100) may determine that refrigerant leakage exists in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage exists and the first sensor (51) detects that the pressure of the refrigerant flowing through the refrigerant circuit (R) is outside a predetermined range. The predetermined range indicates a range that is normally expected for the refrigerant pressure in the refrigerant circuit (R) in the absence of refrigerant leakage. In other words, the control unit (100) may determine that refrigerant leakage exists in the internal space (S) when the refrigerant sensor (50) detects that refrigerant leakage exists and the refrigerant pressure in the refrigerant circuit (R) exceeds the predetermined range.

[0101] In the fourth modification, the control unit (100) may determine the presence of refrigerant leakage in the internal space (S) when it detects that the relative humidity of the internal space (S) is outside a predetermined range. The predetermined range indicates the normally expected range of humidity in the internal space (S) when there is no refrigerant leakage.

[0102] In the third modification, the first sensor (51) may be a refrigerant temperature sensor that detects the temperature of the refrigerant flowing through the refrigerant circuit (R). Because the refrigerant pressure can be determined based on the refrigerant temperature in the refrigerant circuit (R), it is possible to determine whether refrigerant gas is leaking from the refrigerant circuit (R) based on the degree of change in the refrigerant temperature or the refrigerant temperature. Specifically, the control unit (100) determines whether refrigerant is leaking in the internal space (S) when the refrigerant sensor (50) detects refrigerant leakage and the refrigerant temperature sensor detects that the degree of change in the temperature of the refrigerant flowing through the refrigerant circuit (R) or the refrigerant temperature is outside a predetermined range.

[0103] In the third modification, the first sensor (51) may be a sensor that detects an index indicative of the pressure or temperature of the refrigerant flowing through the refrigerant circuit (R).

[0104] In the above embodiment and each modification, the order of steps S11 and S12 may be reversed. That is, after the first sensor (51) detects in step S12 that the rate of change is outside the predetermined range (YES in step S12), the refrigerant sensor (50) may determine whether or not a refrigerant has been detected in step S11.

[0105] In the above embodiment and each modification, step S11 and step S12 may be performed simultaneously.

[0106] In the above embodiment and each modified example, there is no particular limitation on how to calculate the "degree of change." The degree of change may indicate the amount of change from a certain reference value, regardless of a fixed period of time. For example, the degree of change may be a rate of change. The rate of change indicates the ratio of change to a predetermined reference value. For example, if the first sensor (51) is a humidity sensor, the reference humidity is a reference value (e.g., 50% RH) of the relative humidity of the interior space (S) and the relative humidity at the time of refrigerant leakage into the interior space (S) is defined as the first humidity. The rate of change can be defined as the ratio of the first humidity to the reference humidity. Since the value of the first humidity varies depending on the amount of refrigerant leakage, calculating such a rate of change can determine refrigerant leakage and estimate the amount of refrigerant leakage. Furthermore, if the first sensor (51) is an oxygen sensor, the reference value of the oxygen concentration in the interior space (S) is the oxygen concentration in the atmosphere. If the first sensor (51) is a carbon dioxide sensor, the reference value of the carbon dioxide concentration in the interior space (S) is the carbon dioxide concentration in the atmosphere.

[0107] In step S12 of the above embodiment, multiple fixed periods may be set. For example, suppose the fixed periods are set to 1 minute, 1.5 minutes, and 3 minutes. A different predetermined range ΔRH is set for each of these fixed periods. ０ The degree of humidity change ΔRH in any given period is set to be outside the predetermined range ΔRH ０If this is the case, the determination in step S12 may be YES. By providing a plurality of predetermined periods in this way, the accuracy of refrigerant leakage detection can be improved.

[0108] The interior space (S) may be any space within the container (1), and may be, for example, only the storage space (3).

[0109] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments and modifications may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired. The terms "first," "second," etc., described above, are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms.

[0110] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for internal refrigeration devices and refrigerated storage cabinets.

[0111] REFRIGERATED SYMBOLS 1 Container (refrigerated storage) 10 In-storage refrigeration device 30 In-storage fan 30b In-storage fan motor (motor) 50 Refrigerant sensor 51 First sensor 100 Control unit R Refrigerant circuit S In-storage space

Claims

1. An internal refrigeration device that cools an internal space (S) using a refrigerant circuit (R) that performs a refrigeration cycle, comprising: a refrigerant sensor (50) for detecting refrigerant leaked in the internal space (S); a first sensor (51) for detecting an indicator different from the refrigerant; and a control unit (100) that determines whether refrigerant has leaked in the internal space (S) based on detection results of the refrigerant sensor (50) and the first sensor (51).

2. The in-compartment refrigeration device according to claim 1, wherein the first sensor (51) detects a gas component in the in-compartment space (S), and the control unit (100) determines whether or not a refrigerant leak has occurred in the in-compartment space (S) when the refrigerant sensor (50) detects a refrigerant leak and when the first sensor (51) detects that the concentration of the gas component in the in-compartment space (S) or a degree of change in the concentration is outside a predetermined range.

3. The internal refrigeration device according to claim 1 or 2, wherein the first sensor (51) detects humidity, oxygen or carbon dioxide in the internal space (S).

4. The in-compartment refrigeration device according to any one of claims 1 to 3, wherein the first sensor (51) detects the pressure of the gas in the internal space (S), and the control unit (100) determines the occurrence of refrigerant leakage in the internal space (S) when the refrigerant sensor (50) detects a refrigerant leakage and when the first sensor (51) detects that the pressure of the gas in the internal space (S) or a degree of change in the pressure is outside a predetermined range.

5. The in-compartment refrigeration device according to any one of claims 1 to 4, further comprising an internal fan (30) for circulating air in the internal space (S), wherein the first sensor (51) detects a current value of a motor (30a) for driving the internal fan (30), and the control unit (100) determines whether or not a refrigerant leak has occurred in the internal space (S) when the refrigerant sensor (50) detects a refrigerant leak and the first sensor (51) detects that the current value of the motor (30a) or a degree of change in the current value is outside a predetermined range.

6. The in-compartment refrigeration device according to any one of claims 1 to 5, wherein the first sensor (51) detects a pressure or a temperature of the refrigerant flowing through the refrigerant circuit (R), and the control unit (100) determines the occurrence of a refrigerant leakage in the in-compartment space (S) when the refrigerant sensor (50) detects a refrigerant leakage and the first sensor (51) detects that an index indicating the pressure or temperature of the refrigerant flowing through the refrigerant circuit (R) or a degree of change in the index is outside a predetermined range.

7. A refrigerated storage unit equipped with an internal refrigeration device according to any one of claims 1 to 6.

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