Freezer

Abstract

To provide a freezer capable of detecting failure of a compressor.SOLUTION: A freezer comprises: a first cooler having a first evaporator; a second cooler having a second evaporator; a first detection unit that detects a temperature of the first evaporator; a second detection unit that detects a temperature of the second evaporator; and a control unit that performs cooling device determination control to determine the situation of the first cooling device and the second cooling device, based on the difference between a first detection value of the first detection unit and a second detection value of the second detection unit.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a refrigeration device.

Background Art

[0002] Conventionally, a refrigeration device including a box body having a storage chamber, as disclosed in Patent Document 1, is known. Such a refrigeration device includes a first cooling device and a second cooling device that cool the storage chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the refrigeration device as described above, if the cooling device fails, the cooling performance of the refrigeration device may deteriorate.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a refrigeration device capable of detecting a failure of a cooling device.

Means for Solving the Problems

[0006] One aspect of the refrigeration device according to the present invention a first cooling device having a first evaporator; a second cooling device having a second evaporator; a first detection unit that detects the temperature of the first evaporator; a second detection unit that detects the temperature of the second evaporator; a control unit that performs cooling device determination control for determining the status of the first cooling device and the second cooling device based on the difference between a first detection value of the first detection unit and a second detection value of the second detection unit.

Effects of the Invention

[0007] According to the present invention, a refrigeration device capable of detecting a failure of a cooling device can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] Hereinafter, a refrigeration device according to the present invention will be described with reference to the drawings. The same components are denoted by the same reference numerals. The matters described below together with the accompanying drawings are for explaining exemplary embodiments and not for showing the only embodiment.

[0010] [Embodiment] With reference to FIGS. 1 to 8, a refrigeration device 1 according to an embodiment of the present invention will be described.

[0011] FIG. 1 is a perspective view of a refrigeration device 1 according to an embodiment of the present invention. Further, FIG. 2 is a front view of the refrigeration device 1 with the door omitted. Further, FIG. 3 is a front view of the refrigeration device 1 with the left cover 213a and the right cover 213b omitted from the refrigeration device 1 shown in FIG. 2. Further, FIG. 4 is a diagram showing the configuration of the cooling device.

[0012] The refrigeration device 1 is, for example, an ultra-low temperature freezer. An ultra-low temperature freezer refers to a device that cools the interior of the cabinet to an ultra-low temperature (for example, about -80°C). Note that the refrigeration device 1 may be a pharmaceutical cold storage, a blood cold storage, or a thermostat.

[0013] Note that hereinafter, when explaining the structure of the refrigeration device 1 and each member constituting the refrigeration device 1, the orthogonal coordinate system (X, Y, Z) shown in each figure may be used. The X direction coincides with the front-rear direction of the refrigeration device 1. The + side in the X direction coincides with the front side of the refrigeration device 1. The - side in the X direction coincides with the rear side of the refrigeration device 1.

[0014] Further, the Y direction coincides with the left-right direction of the refrigeration device 1 and the width direction of the refrigeration device 1. The + side in the Y direction coincides with the left side when the refrigeration device 1 is viewed from the front. The - side in the Y direction coincides with the right side when the refrigeration device 1 is viewed from the front. The Z direction coincides with the up-down direction of the refrigeration device 1. The + side in the Z direction coincides with the upper side of the refrigeration device 1. The - side in the Z direction coincides with the lower side of the refrigeration device 1.

[0015] Hereinafter, the basic configuration of the refrigeration device 1 will be briefly described. The refrigeration device 1 according to the present embodiment includes a main body 2 and a machine housing portion 3 provided below the main body 2.

[0016] The main body 2 has a box body 21, a door portion 22, and a control panel 23.

[0017] The box body 21 is formed of, for example, a metal plate and / or a synthetic resin plate. The box body 21 is constituted by a box-shaped member with an open front surface. At the central portion in the left-right direction of the opening 210 of the box body 21, a column portion 211 extending in the vertical direction is provided. The box body 21 may have a double structure constituted by an inner box and an outer box covering the inner box.

[0018] The upper end portion of the column portion 211 is fixed to the front end portion of the top plate portion 212 (described later) of the box body 21. The lower end portion of the column portion 211 is fixed to the front end portion of the bottom plate portion 216 (described later) of the box body 21.

[0019] The box body 21 has a top plate portion 212, a rear plate portion 213, a left plate portion 214, a right plate portion 215, and a bottom plate portion 216. Further, the box body 21 has a storage chamber 217. The storage chamber 217 is a space surrounded by the top plate portion 212, the rear plate portion 213, the left plate portion 214, the right plate portion 215, and the bottom plate portion 216.

[0020] In the case of the present embodiment, the storage chamber 217 is constituted by one space. However, for convenience of explanation, in the storage chamber 217, the space on the left side of the column portion 211 (that is, the space in the left half of the storage chamber 217) is referred to as the left region 217a of the storage chamber 217. The left region 217a corresponds to an example of the first region.

[0021] Also, in the storage chamber 217, the space on the right side of the column portion 211 (that is, the space in the right half of the storage chamber 217) is referred to as the right region 217b of the storage chamber 217. The right region 217b corresponds to an example of the second region.

[0022] In addition, a heat insulating material (not shown) is disposed in the space between the outer surface and the inner surface of the box body 21.

[0023] The door portion 22 is a so-called sliding door type door and is provided at the opening 210 of the storage chamber 217. The door portion 22 closes the storage chamber 217 from the front.

[0024] The door part 22 has a left door 220 and a right door 221. The left door 220 corresponds to an example of the first door. The left door 220 is provided between a first inner rail (not shown) provided on the top plate part 212 and a second inner rail (not shown) provided on the bottom plate part 216. The left door 220 is movable left and right while being guided by the first inner rail and the second inner rail.

[0025] The right door 221 corresponds to an example of the second door and is provided between a first outer rail (not shown) provided on the top plate part 212 and a second outer rail (not shown) provided on the bottom plate part 216. The right door 221 is provided outside (in other words, in the front side) of the left door 220. The right door 221 is movable left and right while being guided by the first outer rail and the second outer rail.

[0026] The state where the left door 220 is located at the leftmost position is the closed state of the left door 220. In the closed state, the left door 220 faces the left region 217a of the storage chamber 217 in the front-rear direction. In other words, in the closed state, the left door 220 closes the left region 217a of the storage chamber 217 from the front.

[0027] In addition, the state where the left door 220 has moved to the right from the position in the closed state is the open state of the left door 220. Also, the state where the left door 220 is located at the rightmost position is referred to as the fully open state of the left door 220.

[0028] The state where the right door 221 is located at the rightmost position is the closed state of the right door 221. In the closed state, the right door 221 faces the right region 217b of the storage chamber 217 in the front-rear direction. In other words, in the closed state, the right door 221 closes the right region 217b of the storage chamber 217 from the front.

[0029] In addition, the state where the right door 221 has moved to the left from the position in the closed state is the open state of the right door 221. Also, the state where the right door 221 is located at the leftmost position is referred to as the fully open state of the right door 221.

[0030] When the left door 220 is in the closed state and the right door 221 is also in the closed state, the door unit 22 is in the closed state. On the other hand, when the left door 220 or the right door 221 is in the open state, the door unit 22 is in the open state.

[0031] Note that the structure of the door unit is not limited to the structure of the door unit 22 described above. The door unit may be, for example, a so-called double-opening door constituted by a pair of rotatable doors.

[0032] The control panel 23 is provided on the front surface of the box body 21. Note that the position of the control panel 23 is not particularly limited.

[0033] The control panel 23 is a device for the user to input information. The control panel 23 has an operation unit and a display unit. The operation unit is a device for the user to input information.

[0034] The input information may be, for example, the operating conditions of the refrigeration device 1. The operating conditions may include, for example, the operating mode of the refrigeration device 1 and the set temperature of the storage chamber 217 (hereinafter sometimes referred to as the set temperature inside the cabinet).

[0035] The display unit displays information regarding the refrigeration device 1. The information regarding the refrigeration device 1 may include, for example, information such as the operating mode of the refrigeration device 1 and the temperature of the storage chamber 217 (hereinafter sometimes referred to as the temperature inside the cabinet).

[0036] The machine storage unit 3 is disposed directly below the main body unit 2. Some of the devices constituting the cooling device 4 (see FIG. 4) are disposed in the machine storage unit 3. The devices disposed in the machine storage unit 3 are, for example, the left compressor 500, the left decompressor 502, the right compressor 600, and the right decompressor 602 described later. The cooling device 4 is configured to be able to cool the storage chamber 217 to a temperature equal to or lower than a predetermined temperature (for example, -80°C or lower).

[0037] As shown in FIGS. 2 to 4, the cooling device 4 includes a left cooling device 5, a right cooling device 6, and a control unit 7. The left cooling device 5 and the right cooling device 6 are independent cooling devices from each other.

[0038] The left cooling device 5 corresponds to an example of the first cooling device and cools the storage chamber 217. Specifically, the left cooling device 5 cools the left region 217a of the storage chamber 217.

[0039] The left cooling device 5 includes a left refrigeration circuit 50, a left first temperature detection unit 51, a left second temperature detection unit 52, and a left blower 53.

[0040] The left refrigeration circuit 50 includes a left compressor 500, a left condenser 501, a left decompressor 502, and a left evaporator 503.

[0041] Elements constituting the left refrigeration circuit 50 are connected to each other by a pipe (also referred to as a left pipe or a first pipe). The refrigerant in the pipe circulates through the left refrigeration circuit 50 in the direction indicated by arrow A5 in FIG. 4 while changing its state, thereby cooling the storage chamber 217.

[0042] The left compressor 500 corresponds to an example of the first compressor and operates under the control of the control unit 7 described later to move the refrigerant in the pipe. The refrigerant discharged from the left compressor 500 (also referred to as the first refrigerant) passes through the elements constituting the left refrigeration circuit 50 and returns to the left compressor 500 again. The first refrigerant flows in the direction indicated by arrow A5 in FIG. 4 in the left refrigeration circuit 50. Details of the operation of the left compressor 500 will be described later.

[0043] Since the configurations of the left condenser 501 and the left decompressor 502 are the same as those of the condenser and the decompressor in a conventionally known refrigeration device, the description thereof is omitted.

[0044] The left evaporator 503 is a pipe made of, for example, copper or aluminum. The left evaporator 503 is provided on the rear plate portion 213 of the box body 21. Specifically, the left evaporator 503 is provided in the left half portion of the rear plate portion 213.

[0045] In other words, the left evaporator 503 is provided at a position facing the left region 217a of the storage chamber 217 in the front-rear direction on the rear plate portion 213.

[0046] The left evaporator 503 extends from above to below while meandering in the left-right direction. The left evaporator 503 is covered from the front by a left cover 213a fixed to the front surface of the rear plate portion 213.

[0047] There is a left cooling space 218a between the rear plate portion 213 and the left cover 213a. When the refrigerant evaporates inside the left evaporator 503, the air in contact with the left evaporator 503 in the left cooling space 218a is cooled.

[0048] The air (cold air) cooled in the left cooling space 218a is blown by a left blower 53 described later into the left region 217a of the storage chamber 217. As a result, the left region 217a of the storage chamber 217 is cooled.

[0049] The left first temperature detection unit 51 is, for example, a temperature sensor such as a thermistor, and is fixed to the left evaporator 503. The left first temperature detection unit 51 corresponds to an example of the first detection unit. The detection value of the left first temperature detection unit 51 corresponds to an example of the first detection value.

[0050] The left first temperature detection unit 51 detects the temperature of the left evaporator 503 at a predetermined cycle. The left first temperature detection unit 51 sends the detected information (detection value) to a control unit 7 described later.

[0051] The detection value of the left first temperature detection unit 51 is used for controlling the left heater 54 (see FIG. 4) for removing frost generated on the left evaporator 503 (also referred to as defrost control). Note that the detection value of the left first temperature detection unit 51 is not used for controlling the operation of the left compressor 500 (also referred to as compressor operation control).

[0052] The left second temperature detection unit 52 is, for example, a temperature sensor such as a thermistor, and is provided in the left region 217a of the storage chamber 217. Specifically, the left second temperature detection unit 52 is provided at the upper end of the left cooling space 218a.

[0053] The left second temperature detection unit 52 detects the temperature of the cold air blown by the left blower 53 described later. The cold air blown by the left blower 53 is the cold air blown from the left cooling space 218a to the left region 217a of the storage chamber 217 by the left blower 53. The left second temperature detection unit 52 sends the detected information (detection value) to the control unit 7 described later.

[0054] The detection value of the left second temperature detection unit 52 is used for controlling the operation of the left compressor 500 (also referred to as compressor operation control).

[0055] The left blower 53 (see FIG. 2) blows the cold air in the left cooling space 218a into the storage chamber 217 (specifically, the left region 217a) under the control of the control unit 7 described later. That is, the refrigeration device 1 according to the present embodiment is a so-called forced convection refrigeration device that circulates the cold air in the storage chamber 217 by a blower.

[0056] The left blower 53 is a blower such as a fan. The left blower 53 is provided on the left cover 213a. Specifically, the left blower 53 is provided at the upper end of the central portion in the left-right direction of the left cover 213a.

[0057] The left blower 53 faces the left region 217a in the front-rear direction. Also, the left blower 53 faces the left door 220 in the front-rear direction when the left door 220 is in the closed state. That is, the cold air blown by the left blower 53 flows toward the left door 220 when the left door 220 is in the closed state.

[0058] Note that the position of the left blower is not limited to the above position. The left blower may be provided at various positions capable of blowing cold air into the left region 217a.

[0059] The right cooling device 6 corresponds to an example of the second cooling device and cools the storage chamber 217. Specifically, the right cooling device 6 cools the right region 217b of the storage chamber 217.

[0060] The right cooling device 6 includes a right refrigeration circuit 60, a right first temperature detection unit 61, a right second temperature detection unit 62, and a right blower 63.

[0061] The right refrigeration circuit 60 includes a right compressor 600, a right condenser 601, a right decompressor 602, and a right evaporator 603. Such a right refrigeration circuit 60 is a refrigeration circuit having the same configuration as (in other words, having the same cooling performance as) the left refrigeration circuit 50. The right refrigeration circuit 60 is a refrigeration circuit separate from the left refrigeration circuit 50.

[0062] Elements constituting the right refrigeration circuit 60 are connected to each other by pipes (also referred to as left pipes or second pipes). As the refrigerant in the pipes changes its state and circulates in the direction indicated by arrow A6 in FIG. 4 through the right refrigeration circuit 60, the storage chamber 217 is cooled.

[0063] The right compressor 600 corresponds to an example of the second compressor and operates under the control of the control unit 7 described later to move the refrigerant in the piping. The refrigerant discharged from the right compressor 600 (also referred to as the second refrigerant) passes through each element constituting the right refrigeration circuit 60 and returns to the right compressor 600 again. The second refrigerant flows in the right refrigeration circuit 60 in the direction indicated by the arrow A6 in FIG. 4. Details of the operation of the right compressor 600 will be described later.

[0064] The configurations of the right condenser 601 and the right decompressor 602 are the same as those of the condenser and decompressor in a conventionally known refrigeration device, so the description thereof is omitted.

[0065] The right evaporator 603 is, for example, a pipe made of copper or aluminum. The right evaporator 603 is provided on the rear plate portion 213 of the box body 21. Specifically, the right evaporator 603 is provided in the right half portion of the rear plate portion 213. In other words, the right evaporator 603 is provided at a position facing the right region 217b of the storage chamber 217 in the front-rear direction on the rear plate portion 213.

[0066] The right evaporator 603 extends from above to below while meandering in the left-right direction. The right evaporator 603 is covered from the front by a right cover 213b fixed to the front surface of the rear plate portion 213.

[0067] A right cooling space 218b exists between the rear plate portion 213 and the right cover 213b. As the refrigerant evaporates inside the right evaporator 603, the air in contact with the right evaporator 603 in the right evaporator 603 is cooled.

[0068] The air (cold air) cooled in the right cooling space 218b is blown by the right blower 63 described later into the right region 217b of the storage chamber 217. As a result, the right region 217b of the storage chamber 217 is cooled.

[0069] The right first temperature detection unit 61 is, for example, a temperature sensor such as a thermistor, and is fixed to the right evaporator 603. The right first temperature detection unit 61 corresponds to an example of the second detection unit. The detection value of the right first temperature detection unit 61 corresponds to an example of the second detection value.

[0070] The right first temperature detection unit 61 detects the temperature of the right evaporator 603 at a predetermined cycle. The right first temperature detection unit 61 sends the detected information (detection value) to the control unit 7 described later.

[0071] The detection value of such a right first temperature detection unit 61 is used for the control of the right heater 64 (see FIG. 4) for removing the frost generated on the right evaporator 603 (also referred to as defrosting control). Note that the detection value of the right first temperature detection unit 61 is not used for the control of the operation of the right compressor 600 (also referred to as compressor operation control).

[0072] The right second temperature detection unit 62 is, for example, a temperature sensor such as a thermistor, and is provided in the right region 217b of the storage chamber 217. Specifically, the right second temperature detection unit 62 is provided at the upper end of the right cooling space 218b.

[0073] The right second temperature detection unit 62 detects the temperature of the cold air blown by the right blower 63 described later. The cold air blown by the right blower 63 is the cold air blown from the right cooling space 218b to the right region 217b of the storage chamber 217. The right second temperature detection unit 62 sends the detected information (detection value) to the control unit 7 described later.

[0074] The detection value of such a right second temperature detection unit 62 is used for the control of the operation of the right compressor 600 (also referred to as compressor operation control).

[0075] The right blower 63 blows the cold air in the right cooling space 218b into the storage chamber 217 (specifically, the right region 217b) under the control of the control unit 7 described later.

[0076] The right blower 63 is a blower such as a fan. The right blower 63 is provided on the right cover 213b. Specifically, the right blower 63 is provided at the upper end of the central portion in the left-right direction of the right cover 213b.

[0077] The right blower 63 (see FIG. 2) faces the right region 217b in the front-rear direction. Also, the right blower 63 faces the right door 221 in the front-rear direction when the right door 221 is in the closed state. That is, the cold air blown by the right blower 63 flows toward the right door 221 when the right door 221 is in the closed state.

[0078] Note that the position of the right blower is not limited to the above-described position. The right blower may be provided at various positions capable of blowing cold air into the right region 217b.

[0079] The operation of the cooling device 4 having the above configuration is controlled by the control unit 7. The control unit 7 may be a general-purpose (micro) computer having an input port, an output port, an arithmetic device, and the like.

[0080] Substantially, the control unit 7 may have a configuration in which a CPU, a ROM, a RAM, an HDD, etc. are connected by a bus, or a configuration composed of a one-chip LSI or the like. The control unit 7 is disposed, for example, in the machine storage unit 3.

[0081] Hereinafter, the control executed by the control unit 7 will be described. The control unit 7 controls the operations of the left cooling device 5 and the right cooling device 6 according to the situation of the refrigeration device 1.

[0082] First, with reference to FIGS. 5 and 6, the compressor operation control executed by the control unit 7 will be described. FIG. 5 is a flowchart of the compressor operation control. FIG. 6 is a timing chart regarding the operations of the left compressor 500 and the right compressor 600 in the compressor operation control.

[0083] The compressor operation control is for controlling to improve the cooling performance of the cooling device 4. In the compressor operation control, the control unit 7 controls the cooling operations of the left cooling device 5 and the right cooling device 6 in conjunction based on the detected temperature of one of the left cooling device 5 and the right cooling device 6.

[0084] Specifically, in the compressor operation control, the control unit 7 controls the left cooling device 5 and the right cooling device 6 in conjunction based on the detected temperature of the cooling device with the higher detected temperature among the left cooling device 5 and the right cooling device 6.

[0085] Note that controlling in conjunction means that the control unit 7 controls the operations of the left cooling device 5 and the right cooling device 6 in an associated manner based on common information (the detected temperature of one of the cooling devices).

[0086] In step S1 of FIG. 5, the control unit 7 acquires temperature information. Specifically, the control unit 7 acquires information detected by the left second temperature detection unit 52 of the left cooling device 5 (hereinafter also referred to as first in - storage temperature information) at a predetermined timing (time interval).

[0087] The first in - storage temperature information is information regarding the temperature of the cold air blown by the left blower 53. Specifically, the first in - storage temperature information is information regarding the temperature of the cold air blown from the left cooling space 218a to the left region 217a of the storage chamber 217.

[0088] Also, the control unit 7 acquires information detected by the right second temperature detection unit 62 of the right cooling device 6 (hereinafter also referred to as second in - storage temperature information) at a predetermined timing (time interval).

[0089] The second in - storage temperature information is information regarding the temperature of the cold air blown by the right blower 63. Specifically, the second in - storage temperature information is information regarding the temperature of the cold air blown from the right cooling space 218b to the right region 217b of the storage chamber 217.

[0090] The timing at which the control unit 7 acquires the first internal temperature information and the timing at which the control unit 7 acquires the second internal temperature information may be the same.

[0091] Next, in step S2 of FIG. 5, the control unit 7 compares the temperature information. Specifically, the control unit 7 compares the acquired first internal temperature information and the second internal temperature information.

[0092] Next, in step S3 of FIG. 5, the control unit 7 identifies the cooling device to be driven first. Specifically, the control unit 7 identifies, among the left cooling device 5 and the right cooling device 6, the cooling device that has detected the temperature information indicating the higher temperature as the specific cooling device that starts the cooling operation first.

[0093] In addition, in step S3 of FIG. 5, the cooling device that is not identified as the specific cooling device is referred to as the non-specific cooling device. The non-specific cooling device is a cooling device that starts the cooling operation after the specific cooling device.

[0094] For example, when the temperature indicated by the first internal temperature information is higher than the temperature indicated by the second internal temperature information, the left cooling device 5 is the specific cooling device. On the other hand, when the temperature indicated by the second temperature information is higher than the temperature indicated by the first internal temperature information, the right cooling device 6 is the specific cooling device.

[0095] In addition, the control unit 7 may not identify the specific cooling device in step S3 of FIG. 5. Specifically, when both the temperature indicated by the first internal temperature information and the temperature indicated by the second internal temperature information are equal to or lower than the predetermined temperature, the control unit 7 may not identify the specific cooling device.

[0096] In step S3 of FIG. 5, when the specific cooling device is not identified, the differential control of the compressor described later does not have to be executed. This is because if both the temperature indicated by the first internal temperature information and the temperature indicated by the second internal temperature information are in a state of being equal to or lower than the predetermined temperature, the storage chamber 217 is sufficiently cooled.

[0097] The processes of steps S1 to S3 in FIG. 5 as described above may be executed in a state where the left compressor 500 of the left cooling device 5 and the right compressor 600 of the right cooling device 6 are stopped (also referred to as the OFF state of the compressor).

[0098] However, the processes of steps S1 to S3 in FIG. 5 may also be executed in a state where the left compressor 500 of the left cooling device 5 or the right compressor 600 of the right cooling device 6 is driven (also referred to as the ON state of the compressor).

[0099] The processes of steps S1 to S3 in FIG. 5 may be regarded as pre - processes for each cycle operation in the differential control of the compressor described later.

[0100] Next, in step S4 of FIG. 5, the control unit 7 controls the operation of the cooling device. The control that the control unit 7 executes in step S4 of FIG. 5 is referred to as the differential control of the compressor. The control unit 7 starts the differential control of the compressor in step S4 of FIG. 5.

[0101] The differential control of the compressor may be executed when a specific cooling device is specified by the control unit 7 in step S3 described above.

[0102] The differential control of the compressor is a control that shifts the timing of turning off the compressor of the specific cooling device and the timing of turning off the compressor of the non - specific cooling device by a predetermined time.

[0103] In addition, turning off the compressor of the specific cooling device corresponds to turning off the cooling operation of the specific cooling device. Also, turning on the compressor of the specific cooling device corresponds to turning on the cooling operation of the specific cooling device.

[0104] Furthermore, turning off the compressor of the unspecified cooling device corresponds to turning off the cooling operation of the unspecified cooling device. Also, turning on the compressor of the unspecified cooling device corresponds to turning on the cooling operation of the unspecified cooling device. Hereinafter, specific processing of differential control of the compressor will be described.

[0105] In step S4, the control unit 7 first turns on the cooling device specified as the specific cooling device. At this time, the unspecified cooling device not specified as the specific cooling device is in the OFF state.

[0106] Here, with reference to FIG. 6, an example of differential control of the compressor will be described when the specific cooling device is the left cooling device 5 and the unspecified cooling device is the right cooling device 6. Therefore, in the following description, the left cooling device 5 may be appropriately read as the specific cooling device. Also, in the following description, the right cooling device 6 may be appropriately read as the unspecified cooling device.

[0107] In FIG. 6, the horizontal axis represents time. At time T1 in FIG. 6, the processing of steps S1 to S3 described above has been completed. The specific cooling device is the left cooling device 5. In other words, among the left cooling device 5 and the right cooling device 6, the cooling device with the higher detected temperature is the left cooling device 5.

[0108] When the specific cooling device is the left cooling device 5, the control unit 7 controls the operations of the left cooling device 5 and the right cooling device 6 in conjunction based on the first in - chamber temperature information in the differential control of the compressor.

[0109] For convenience of explanation, it is assumed that before time T1 in FIG. 6, the left compressor 500 of the left cooling device 5 and the right compressor 600 of the right cooling device 6 are in the stopped state (OFF state).

[0110] At time T1, the control unit 7 drives the left compressor 500 of the left cooling device 5. That is, the control unit 7 sets the left compressor 500 to the driving state (ON state). At time T1, the right compressor 600 is in the stopped state (OFF state).

[0111] Then, at time T2, the control unit 7 turns off the left compressor 500. The control unit 7 determines the timing (i.e., at time T2) to turn off the left compressor 500 based on the first in - chamber temperature information. The first in - chamber temperature information is the information acquired by the control unit 7 from the left second temperature detection unit 52 after time T1 (i.e., in the ON state of the left compressor 500).

[0112] Specifically, when the temperature indicated by the first in - chamber temperature information is equal to or higher than a predetermined temperature in the ON state of the left compressor 500, the control unit 7 turns off the left compressor 500. The predetermined temperature is a threshold value for determining the timing to switch the compressor of the specific cooling device from the ON state to the OFF state.

[0113] In addition, the control unit 7 may adjust the output (in other words, the rotational speed) of the left compressor 500 according to the temperature indicated by the first in - chamber temperature information. In this case, the left compressor 500 may be a compressor whose output (rotational speed) can be adjusted (for example, an inverter compressor). However, the left compressor 500 may also be a compressor with a constant output (rotational speed).

[0114] As described above, time T2 is determined based on the first in - chamber temperature information acquired by the control unit 7 from the left second temperature detection unit 52 in the ON state of the left compressor 500. That is, the driving time of the left compressor 500 is not a predetermined time, but a time determined according to the first in - chamber temperature information. Therefore, the driving time of the specific cooling device in one - cycle operation of the differential control of the compressor described later is determined for each cycle operation.

[0115] Further, at time T2, the control unit 7 turns on the right compressor 600. That is, in this example, the control unit 7 turns off the left compressor 500 and simultaneously turns on the right compressor 600. Therefore, in one cycle operation of the compressor operation control (described later), there is no time when neither the left compressor 500 nor the right compressor 600 is driven.

[0116] The left compressor 500 and the right compressor 600 may be driven simultaneously. The time from time T1 to time T2 is referred to as the compressor differential time. The compressor differential time is the time from when the left compressor 500 is driven until the right compressor 600 is driven.

[0117] Still, in this example, the time from time T1 to time T2 is also the time from when the left compressor 500 becomes ON until it becomes OFF (that is, the driving time of the left compressor 500). Therefore, the compressor differential time is equal to the driving time of the left compressor 500.

[0118] However, the compressor differential time may be different from the driving time of the left compressor 500. That is, the control unit 7 may turn on the right compressor 600 while the left compressor 500 is ON.

[0119] As described above, the compressor differential time is not a predetermined time, but is a time determined by the control unit 7 according to the temperature information in the first storage. However, the compressor differential time may be a predetermined time. The time T2 when the right compressor 600 is turned on may be predetermined based on the time T1 when the left compressor 500 becomes ON.

[0120] The control unit 7 maintains the left compressor 500 in the OFF state until time T3. Also, the control unit 7 maintains the right compressor 600 in the ON state until time T3. Then, at time T3, the control unit 7 turns off the right compressor 600.

[0121] The time from time T2 to time T3 is referred to as the compressor stop time of the left compressor 500. The compressor stop time may be a preset value. Alternatively, the compressor stop time may be determined based on the above-described compressor differential time. The time from time T1 to time T2 is the compressor stop time of the right compressor 600.

[0122] In addition, the compressor stop time can also be regarded as the time provided for the safe use of the compressor. It is preferable that the compressor stop time is within the time predefined by the manufacturer as the specification of the compressor.

[0123] The control unit 7 executes the processing of the above-described steps S1 to S3 in the state at time T3 or before time T3. Then, after time T3, the control unit 7 executes the processing of step S4 again.

[0124] In addition, the operation from time T1 to time T3 is one-cycle operation of the compressor operation control. One-cycle operation of the compressor operation control may be regarded as an operation including the ON state of the compressor of the specific cooling device and the OFF state of the compressor of the specific cooling device once each.

[0125] The time of one-cycle operation (cycle time) is the sum of the driving time (that is, the ON state time) and the stop time (that is, the OFF state time) of the compressor in the specific cooling device. Since the driving time of the compressor in the specific cooling device is determined based on the detected temperature of the specific cooling device (that is, the first temperature information), the time of one-cycle operation of the compressor operation control may be different for each cycle operation.

[0126] In the case of the example shown in FIG. 6, one cycle operation of the left compressor 500 is the operation of the left compressor 500 from time T1 to time T3. And, one cycle operation of the right compressor 600 corresponding to one cycle operation of the left compressor 500 is the operation of the right compressor 600 from time T1 to time T3. Therefore, the first cycle time and the second cycle time are equal.

[0127] After time T3 in FIG. 6, based on the result of the process corresponding to the above-described steps S1 to S3 executed by the control unit 7 before time T3, the process corresponding to the above-described step S4 is repeated.

[0128] FIG. 6 also shows the states of the left compressor 500 and the right compressor 600 after time T3. Specifically, the control unit 7 turns on the left compressor 500 at time T3. Also, in the timing chart shown in FIG. 6, the control unit 7 turns off the right compressor 600 at time T3.

[0129] The reason for this is that the left cooling device 5 was identified again as the specific cooling device by the process corresponding to the above-described steps S1 to S3 executed by the control unit 7 before time T3.

[0130] When the right cooling device 6 was identified as the specific cooling device by the above-described steps S1 to S3 executed by the control unit 7 before time T3, the control unit 7 turns on the right compressor 600 at time T3. In addition, when no external factors such as the door portion 22 being opened occur, basically, the order of operation between the left compressor 500 and the right compressor 600 does not change.

[0131] Also, when the right cooling device 6 was identified as the specific cooling device by the above-described steps S1 to S3 executed by the control unit 7 before time T3, the control unit 7 turns off the left compressor 500 at time T3.

[0132] As described above, in one cycle of compressor operation control, the control unit 7 shifts by a predetermined time the timing at which the left compressor 500 is turned OFF (specifically, time T2) from the timing at which the right compressor 600 is turned OFF (specifically, time T3).

[0133] In other words, in one cycle of compressor operation control, the control unit 7 shifts by a predetermined time the timing at which the left compressor 500 is turned on (specifically, time T1) and the timing at which the right compressor 600 is turned on (specifically, time T2).

[0134] In addition, during one cycle of compressor operation control, the control unit 7 determines the timing to turn on the left compressor 500 and the timing to turn on the right compressor 600 based on the first internal temperature information obtained from the left cooling device 5 (i.e., the specific cooling device).

[0135] In other words, during one cycle of compressor operation control, the control unit 7 controls the left cooling device 5 and the right cooling device 6 in conjunction with each other based on the first internal temperature information obtained from the left cooling device 5 (i.e., the specific cooling device).

[0136] More specifically, in one cycle of compressor operation control, the control unit 7 controls the left compressor 500 and the right compressor 600 based on the first internal temperature information obtained from the left cooling device 5 (i.e., the specific cooling device) without using the second internal temperature information detected by the right cooling device 6 (i.e., the non-specific cooling device).

[0137] Next, a description will be given of the cooling device determination control performed by the control unit 7. The cooling device determination control is a control for determining the status of the left cooling device 5 and the right cooling device 6. In the cooling device determination control, the control unit 7 determines a failure of the left cooling device 5 and the right cooling device 6. Such a determination control is referred to as a first failure determination control.

[0138] Further, in the cooling device determination control, the control unit 7 determines the status of the capabilities of the left cooling device 5 and the right cooling device 6. Such determination control is referred to as cooling capacity determination control.

[0139] Hereinafter, with reference to FIG. 7, the cooling device determination control will be described. FIG. 7 is a flowchart of the cooling device determination control implemented by the control unit 7. The control unit 7 implements the cooling device determination control in the above-described compressor operation control.

[0140] First, in step S101 of FIG. 7, the control unit 7 acquires temperature information. The temperature information acquired by the control unit 7 in step S101 is the detected value of the left first temperature detection unit 51 and the detected value of the right first temperature detection unit 61 in one cycle operation of the differential control of the above-described compressor.

[0141] Then, the control unit 7 calculates the difference between the detected value of the left first temperature detection unit 51 and the detected value of the right first temperature detection unit 61 (hereinafter, the temperature difference of the evaporator).

[0142] Incidentally, the left compressor 500 and the right compressor 600 operate at the timing shown in FIG. 6 in the differential control of the compressor.

[0143] Next, in step S102 of FIG. 7, the control unit 7 determines whether the cooling device is malfunctioning. In step S102 of FIG. 7, the control unit 7 determines whether the left cooling device 5 and the right cooling device 6 are malfunctioning.

[0144] In the case of this embodiment, the left compressor 500 and the right compressor 600 operate differentially as shown in FIG. 6 in a normal state.

[0145] Therefore, the magnitude relationship between the detection value of the left first temperature detection unit 51 (i.e., the temperature of the left evaporator 503) and the detection value of the right first temperature detection unit 61 (i.e., the temperature of the right evaporator 603) changes according to the operating states of the left compressor 500 and the right compressor 600. That is, in one cycle of the differential control of the compressor, the temperature difference of the evaporator includes a positive state and a negative state.

[0146] Therefore, when the temperature difference of the evaporator includes a positive state and a negative state in one cycle of the differential control of the compressor, the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are normal.

[0147] On the other hand, when one of the left cooling device 5 and the right cooling device 6 fails, the magnitude relationship between the detection value of the left first temperature detection unit 51 (i.e., the temperature of the left evaporator 503) and the detection value of the right first temperature detection unit 61 (i.e., the temperature of the right evaporator 603) does not change according to the operating states of the left compressor 500 and the right compressor 600. That is, in one cycle of the differential control of the compressor, the temperature difference of the evaporator includes only a positive state or a negative state.

[0148] Specifically, when the left compressor 500 and the right compressor 600 operate differentially as shown in FIG. 6, if the left cooling device 5 (i.e., the specific cooling device) fails, the temperature difference of the evaporator is always in a positive state in one cycle of the differential control of the compressor.

[0149] Therefore, when the temperature difference of the evaporator is always in a positive state in one cycle of the differential control of the compressor, the control unit 7 determines that the left cooling device 5 has failed (in other words, is not normal).

[0150] Also, when the left compressor 500 and the right compressor 600 operate differentially as shown in FIG. 6, if the right cooling device 6 (i.e., the non-specific cooling device) fails, the temperature difference of the evaporator is always in a negative state in one cycle of the compressor operation control.

[0151] Therefore, when the temperature difference of the evaporator is always negative in one cycle operation of the compressor operation control, the control unit 7 determines that the right cooling device 6 is faulty (in other words, not normal).

[0152] When the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are faulty (in “YES” at step S102), the control process proceeds to step S106.

[0153] On the other hand, when the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are not faulty (in “NO” at step S102), the control process proceeds to step S103.

[0154] The processes of step S101 and step S102 described above are the first fault determination control of the control unit 7.

[0155] Next, in step S103 of FIG. 7, the control unit 7 determines whether the temperature condition is satisfied. Specifically, the control unit 7 determines whether the difference between the outside air temperature and the set temperature of the refrigeration device 1 is greater than the first temperature threshold (for example, 3°C). The set temperature of the refrigeration device 1 may be regarded as the target temperature of the storage chamber 217. The first temperature threshold may be a preset value.

[0156] When the difference between the outside air temperature and the set temperature of the refrigeration device 1 is less than or equal to the first temperature threshold, for example, even if the cooling capacity of the left cooling device 5 has decreased, the right cooling device 6 alone can cool the storage chamber 217. Therefore, it is difficult for the control unit 7 to determine the failure of the left cooling device 5.

[0157] Therefore, in the case of this embodiment, when the difference between the outside air temperature and the set temperature of the refrigeration device 1 is less than or equal to the first temperature threshold, the cooling capacity determination control of the control unit 7 described later is not performed.

[0158] When the control unit 7 determines that the temperature condition is satisfied (i.e., “YES” in step S103), the control process proceeds to step S104. Specifically, when the difference between the outside air temperature and the set temperature of the refrigeration device 1 is greater than the first temperature threshold (e.g., 3°C) (i.e., “YES” in step S103), the control process proceeds to step S104.

[0159] On the other hand, when the control unit 7 determines that the temperature condition is not satisfied (i.e., “NO” in step S103), the control process ends.

[0160] Next, in step S104 of FIG. 7, the control unit 7 acquires an average value. Specifically, the control unit 7 calculates the average value of the difference between the detection value of the left first temperature detection unit 51 and the detection value of the right first temperature detection unit 61 in one cycle of the compressor operation control (hereinafter referred to as the average value of the temperature difference of the evaporator). Then, the control unit 7 advances the control process to step S105.

[0161] Next, in step S105 of FIG. 7, the control unit 7 determines whether the cooling capacity of the cooling device is normal. In step S105 of FIG. 7, the control unit 7 determines whether the cooling capacities of the left cooling device 5 and the right cooling device 6 are normal.

[0162] Specifically, in one cycle of the differential control of the compressor, when the average value of the temperature difference of the evaporator is less than or equal to the second temperature threshold and greater than or equal to the third temperature threshold, the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are normal.

[0163] The second temperature threshold corresponds to an example of the first threshold. Also, the third temperature threshold corresponds to an example of the second threshold. The second temperature threshold and the third temperature threshold may be values preset according to the model of the refrigeration device 1.

[0164] At least one of the second temperature threshold and the third temperature threshold may be a temperature determined based on a function (for example, a linear function) preset according to the model of the refrigeration device 1. The function of the threshold value may be a function with the difference between the temperature inside the storage compartment and the set temperature as a variable.

[0165] In addition, examples of the model of the refrigeration device 1 include a normal model in which no device such as a rack is accommodated in the storage compartment 217, or a rack model in which a rack is accommodated in the left region 217a or the right region 217b of the storage compartment 217. The second temperature threshold and the third temperature threshold may be appropriately set according to such a model of the refrigeration device 1.

[0166] The temperature inside the storage compartment is a temperature determined based on the detection values of the left second temperature detection unit 52 and / or the right second temperature detection unit 62. The set temperature may be a preset temperature.

[0167] When the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are normal (\"YES\" in step S105), the control process ends.

[0168] In addition, when the left cooling device 5 and the right cooling device 6 are in a normal state, the reason why the average value of the temperature difference of the evaporator falls within the range of not more than the second temperature threshold and not less than the third temperature threshold in one cycle operation of the differential control of the compressor is substantially the same as the reason described in step S102.

[0169] Specifically, in the case of the present embodiment, the left compressor 500 and the right compressor 600 operate differentially as shown in FIG. 6 in a normal state.

[0170] Therefore, the magnitude relationship between the detection value of the left first temperature detection unit 51 (i.e., the temperature of the left evaporator 503) and the detection value of the right first temperature detection unit 61 (i.e., the temperature of the right evaporator 603) changes according to the operating states of the left compressor 500 and the right compressor 600. That is, in one cycle of the differential control of the compressor, the temperature difference of the evaporator includes a positive state and a negative state. Therefore, the average value of the temperature difference of the evaporator falls within a predetermined range (i.e., equal to or lower than the second temperature threshold and equal to or higher than the third temperature threshold).

[0171] On the other hand, when one of the left cooling device 5 and the right cooling device 6 fails, the magnitude relationship between the detection value of the left first temperature detection unit 51 (i.e., the temperature of the left evaporator 503) and the detection value of the right first temperature detection unit 61 (i.e., the temperature of the right evaporator 603) does not change even if the operating states of the left compressor 500 and the right compressor 600 change. That is, in one cycle of the differential control of the compressor, the temperature difference of the evaporator includes only a positive state or a negative state.

[0172] Specifically, when the left compressor 500 and the right compressor 600 operate differentially as shown in FIG. 6, if the left cooling device 5 fails, the temperature difference of the evaporator will always be in a positive state in one cycle of the compressor operation control. Therefore, the average value of the temperature difference of the evaporator does not fall within the predetermined range (i.e., equal to or lower than the second temperature threshold and equal to or higher than the third temperature threshold), but becomes larger than the second temperature threshold.

[0173] When the average value of the temperature difference of the evaporator is larger than the second temperature threshold in one cycle of the compressor operation control, the control unit 7 determines that the cooling capacity of the left cooling device 5 has decreased.

[0174] On the other hand, when the left compressor 500 and the right compressor 600 operate differentially as shown in FIG. 6, if the right cooling device 6 fails, the temperature difference of the evaporator will always be in a negative state in one cycle of the differential control of the compressor. Therefore, the average value of the temperature difference of the evaporator does not fall within the predetermined range (i.e., equal to or lower than the second temperature threshold and equal to or higher than the third temperature threshold), but becomes smaller than the third temperature threshold.

[0175] When the average value of the temperature difference of the evaporator is smaller than the third temperature threshold in one cycle operation of the differential control of the compressor, the control unit 7 determines that the cooling capacity of the right cooling device 6 has decreased.

[0176] When the control unit 7 determines that one of the left cooling device 5 and the right cooling device 6 is not normal ( "NO" in step S105), the control process proceeds to step S106.

[0177] The processes of step S104 and step S105 described above are the processes of the cooling capacity determination control of the control unit 7.

[0178] Next, in step S106 of FIG. 7, the control unit 7 determines whether or not the notification condition is satisfied.

[0179] First, the case where the control process shifts from step S102 to step S106 will be described. The control unit 7 determines whether or not it has been determined by the determination process of step S102 that the left cooling device 5 has failed continuously twice.

[0180] If it is determined by the determination process of step S102 that the left cooling device 5 has failed continuously twice, the control unit 7 determines in step S106 that the notification condition is satisfied.

[0181] Also, the control unit 7 determines whether or not it has been determined by the determination process of step S102 that the right cooling device 6 has failed continuously twice.

[0182] If it is determined by the determination process of step S102 that the right cooling device 6 has failed continuously twice, the control unit 7 determines in step S106 that the notification condition is satisfied.

[0183] Next, the case where the control process shifts from step S105 to step S106 will be described. The control unit 7 determines, by the determination process in step S105, whether or not it has been determined that the cooling capacity of the left cooling device 5 has decreased twice in a row.

[0184] And, when it is determined by the determination process in step S105 that the cooling capacity of the left cooling device 5 has decreased twice in a row, the control unit 7 determines in step S106 that the notification condition is satisfied.

[0185] In addition, the control unit 7 determines, by the determination process in step S105, whether or not it has been determined that the cooling capacity of the right cooling device 6 has decreased twice in a row.

[0186] And, when it is determined by the determination process in step S105 that the cooling capacity of the right cooling device 6 has decreased twice in a row, the control unit 7 determines in step S106 that the notification condition is satisfied.

[0187] When the control unit 7 determines that the notification condition is satisfied ( "YES" in step S106), the control process proceeds to step S107.

[0188] When the control unit 7 determines that the notification condition is not satisfied ( "NO" in step S106), the control process ends.

[0189] Next, the control unit 7 notifies information regarding the status of the cooling device in step S107 of FIG. 7.

[0190] First, the case where the control process shifts from step S102 via step S106 to step S107 will be described.

[0191] When it is determined twice in a row in the determination process in step S102 that the left cooling device 5 has failed, the control unit 7 notifies, in step S107, information indicating that the left cooling device 5 has failed as information regarding the status of the cooling device.

[0192] The control unit 7 may display information indicating that the left cooling device 5 has failed on the display unit of the control panel 23 (see FIG. 1). Note that the notification method is not particularly limited. The notification method may be light or sound (for example, voice). Further, the control unit 7 may transmit information regarding the status of the cooling device to an external terminal communicatively connected to the refrigeration device 1.

[0193] In the determination process of step S102, when it is determined twice in a row that the right cooling device 6 has failed, in step S107, the control unit 7 notifies, as information regarding the status of the cooling device, information indicating that the right cooling device 6 has failed.

[0194] Next, the case where the control process shifts from step S105 to step S107 via step S106 will be described.

[0195] In the determination process of step S105, when it is determined twice in a row that the cooling capacity of the left cooling device 5 has decreased, in step S107, the control unit 7 notifies, as information regarding the status of the cooling device, information indicating that the cooling capacity of the left cooling device 5 has decreased.

[0196] In the determination process of step S105, when it is determined twice in a row that the cooling capacity of the right cooling device 6 has decreased, in step S107, the control unit 7 notifies, as information regarding the status of the cooling device, information indicating that the cooling capacity of the right cooling device 6 has decreased.

[0197] After the control process of step S107 ends, the control unit 7 ends the control process. The cooling device determination control as described above is repeatedly performed at an appropriate timing while the compressor operation control is being executed.

[0198] Note that the control unit 7 does not have to perform the cooling device determination control when the status of the refrigeration device 1 meets the limitation conditions. The limitation conditions may be regarded as conditions under which the execution of the cooling device determination control is restricted.

[0199] This is because even if the cooling device determination control is performed when the situation of the refrigeration device 1 meets the limiting conditions, the situation of the cooling device cannot be accurately determined. When the situation of the refrigeration device 1 meets the limiting conditions, the control unit 7 may perform the cooling device determination control after the situation of the refrigeration device 1 meets the predetermined conditions.

[0200] Specifically, when the defrosting operation described later is performed in the compressor operation control, the control unit 7 does not perform the cooling device determination control. That is, the performance of the defrosting operation corresponds to an example of the limiting conditions. In this case, after the defrosting operation is performed, when the state of the refrigeration device 1 meets the predetermined conditions, the control unit 7 may perform the cooling device determination control.

[0201] Also, when the door 22 is opened, the control unit 7 does not perform the cooling device determination control. The opening of the door 22 corresponds to an example of the limiting conditions. In this case, after the door 22 is closed, when the state of the refrigeration device 1 meets the predetermined conditions, the control unit 7 may perform the cooling device determination control.

[0202] Also, when the set temperature in the storage compartment is changed, the control unit 7 does not necessarily perform the cooling device determination control. The change in the set temperature in the storage compartment corresponds to an example of the limiting conditions. In this case, after the set temperature in the storage compartment is changed, when the state of the refrigeration device 1 meets the predetermined conditions, the control unit 7 may perform the cooling device determination control.

[0203] Also, when the rotational speeds of the left compressor 500 and the right compressor 600 change, the control unit 7 does not necessarily perform the cooling device determination control. The change in the rotational speeds of the left compressor 500 and the right compressor 600 corresponds to an example of the limiting conditions. In this case, after the rotational speeds of the left compressor 500 and the right compressor 600 change, when the state of the refrigeration device 1 meets the predetermined conditions, the control unit 7 may perform the cooling device determination control.

[0204] The above-mentioned predetermined condition is that the one-cycle operation in the differential control of the compressor is performed a predetermined number of times (for example, three times). That is, when the situation of the refrigeration device 1 meets the limit condition, the control unit 7 performs the cooling device determination control after the one-cycle operation in the differential control of the compressor is performed a predetermined number of times (for example, three times).

[0205] The reason for this is that even when the situation of the refrigeration device 1 meets the limit condition, if the one-cycle operation in the differential control of the compressor is performed a predetermined number of times (for example, three times), the situation of the refrigeration device 1 (in other words, the situation inside the storage) is stable.

[0206] Next, the defrosting control performed by the control unit 7 will be described. In the defrosting control, the control unit 7 controls the defrosting operation for removing the frost adhering to the left evaporator 503 of the left cooling device 5 and the right evaporator 603 of the right cooling device 6. Further, in the defrosting control, the control unit 7 determines the failure of the left cooling device 5 and the right cooling device 6. Such determination processing is referred to as second failure determination control.

[0207] The second failure determination control is a control that can be independently performed from the above-mentioned first failure determination control. That is, the refrigeration device 1 may be provided with a function of performing both the first failure determination control and the second failure determination control, or may be provided with only a function of performing either one of the first failure determination control and the second failure determination control.

[0208] Hereinafter, with reference to FIG. 8, the defrosting control will be described. FIG. 8 is a flowchart of the defrosting control performed by the control unit 7. The control unit 7 performs the defrosting control in the above-mentioned compressor operation control.

[0209] When frost adheres to the left evaporator 503 and the right evaporator 603, the cooling performance of the left cooling device 5 and the right cooling device 6 will decrease. Therefore, the control unit 7 performs a defrosting operation for removing the frost adhering to the left evaporator 503 and the right evaporator 603 at an appropriate timing.

[0210] First, in step S201 of FIG. 8, the control unit 7 determines whether the temperature inside the storage has reached a predetermined temperature. The predetermined temperature is the temperature inside the storage that serves as the criterion for starting the differential control of the compressor.

[0211] The temperature inside the storage is detected based on the detection values of the left second temperature detection unit 52 and the right second temperature detection unit 62. Incidentally, in the state before step S201 is executed, the left compressor 500 and the right compressor 600 are in a stopped state.

[0212] When the control unit 7 determines that the temperature inside the storage has reached the predetermined temperature ( "YES" in step S201), it proceeds with the control process to step S202.

[0213] When the control unit 7 determines that the temperature inside the storage has not reached the predetermined temperature ( "NO" in step S201), it repeats step S201.

[0214] Next, in step S202 of FIG. 8, the control unit 7 starts the differential control of the compressor described above. The control unit 7 turns on the compressor of the cooling device (specifically, the left compressor 500) specified as the cooling device to be driven first in step S3 of FIG. 5.

[0215] Next, in step S203 of FIG. 8, the control unit 7 determines whether a predetermined time (for example, 3 hours) has elapsed since the start of the differential control of the compressor.

[0216] When the control unit 7 determines that a predetermined time (for example, 3 hours) has elapsed since the start of the differential control of the compressor ( "YES" in step S203), it proceeds with the control process to step S204.

[0217] On the other hand, when the control unit 7 determines that a predetermined time (for example, 3 hours) has not elapsed since the start of the differential control of the compressor ( "NO" in step S203), it repeats step S203. That is, the control unit 7 continues for a predetermined time.

[0218] Next, in step S204 of FIG. 8, the control unit 7 stops the compressor operation control. That is, the control unit 7 turns off the left compressor 500 and the right compressor 600. Then, the control unit 7 advances the control process to step S205.

[0219] Next, in step S205 of FIG. 8, the control unit 7 determines the defrosting target. Specifically, it determines the evaporator for defrosting from the left evaporator 503 and the right evaporator 603.

[0220] The control unit 7 compares the detected value of the left first temperature detection unit 51 (that is, the temperature of the left evaporator 503) with the detected value of the right first temperature detection unit 61 (that is, the temperature of the right evaporator 603), and determines the evaporator with the lower temperature as the evaporator for defrosting. The determined evaporator is referred to as the defrosting target evaporator. Then, the control unit 7 advances the control process to step S206.

[0221] Next, in step S206 of FIG. 8, the control unit 7 performs a defrosting operation on the defrosting target evaporator. Specifically, the control unit 7 turns on the heater (left heater 54 or right heater 64) provided around the defrosting target evaporator to heat the defrosting target evaporator. Then, the control unit 7 advances the control process to step S207.

[0222] Next, in step S207 of FIG. 8, the control unit 7 determines whether the left cooling device 5 and the right cooling device 6 are faulty.

[0223] Specifically, when the implementation status of the defrosting operation satisfies the first failure condition, the control unit 7 determines that one of the left cooling device 5 and the right cooling device 6 is faulty.

[0224] The first failure condition is that one of the left evaporator 503 and the right evaporator 603 has been subjected to the defrosting operation three times in a row in step S206.

[0225] When one of the left evaporator 503 and the right evaporator 603 has performed the defrosting operation three times in a row in step S206, the control unit 7 determines that the cooling device having the other evaporator of the left evaporator 503 and the right evaporator 603 (in other words, the evaporator that has not performed the defrosting operation three times in a row) is malfunctioning.

[0226] If the cooling device is malfunctioning, the temperature of the evaporator of the malfunctioning cooling device will not drop. That is, in step S205 described above, the evaporator of the malfunctioning cooling device will not be the evaporator to be defrosted. Therefore, the evaporator that has not performed the defrosting operation three times in a row in step S206 is highly likely to be malfunctioning.

[0227] Specifically, when the left evaporator 503 has performed the defrosting operation three times in a row in step S206, the control unit 7 determines that the right cooling device 6 is malfunctioning.

[0228] Also, when the right evaporator 603 has performed the defrosting operation three times in a row in step S206, the control unit 7 determines that the left cooling device 5 is malfunctioning.

[0229] On the other hand, when the implementation status of the defrosting operation does not satisfy the first failure condition, the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are not malfunctioning (that is, they are normal).

[0230] Specifically, when one of the left evaporator 503 and the right evaporator 603 has not performed the defrosting operation three times in a row in step S206, the control unit 7 determines that the left evaporator 503 and the right evaporator 603 are not malfunctioning (that is, they are normal).

[0231] When the control unit 7 determines that one of the left cooling device 5 and the right cooling device 6 is malfunctioning (in step S207, “YES”), the control process proceeds to step S208.

[0232] On the other hand, when the control unit 7 determines that the left cooling device 5 and the right cooling device 6 are not malfunctioning (i.e., are normal) (in step S207, “NO”), the control process proceeds to step S209.

[0233] In step S208 of FIG. 8, the control unit 7 notifies information indicating that the cooling device determined to be malfunctioning in step S207 (hereinafter referred to as the first malfunctioning cooling device) is malfunctioning.

[0234] The control unit 7 may display information indicating that the first malfunctioning cooling device is malfunctioning on the display unit of the control panel 23 (see FIG. 1). Thereafter, the control unit 7 ends the control process at an appropriate timing.

[0235] Note that the notification method is not particularly limited. The notification method may be light or sound (e.g., voice). Further, the control unit 7 may transmit information indicating that the first malfunctioning cooling device is malfunctioning to an external terminal communicatively connected to the refrigeration device 1.

[0236] Next, in step S209 of FIG. 8, the control unit 7 starts differential control of the compressor. The control unit 7 turns on the compressor of the cooling device specified as the cooling device to be driven first in step S3 of FIG. 5 (specifically, the left compressor 500). Then, the control unit 7 proceeds with the control process to step S210.

[0237] Next, in step S210 of FIG. 8, the control unit 7 determines whether or not the temperature inside the storage has reached the set temperature. The temperature inside the storage is detected based on the detection values of the left second temperature detection unit 52 and the right second temperature detection unit 62.

[0238] When the control unit 7 determines that the temperature inside the storage has reached the set temperature (in step S210, “YES”), the control process proceeds to step S211. In step S210, when the temperature inside the storage has reached the set temperature, it is highly likely that the left cooling device 5 and the right cooling device 6 are operating normally.

[0239] On the other hand, when the control unit 7 determines that the temperature inside the storage has not reached the predetermined temperature ( "NO" in step S210), the control process proceeds to step S212.

[0240] Next, in step S211 of FIG. 8, the control unit 7 stops the differential control of the compressor. That is, the control unit 7 turns off the left compressor 500 and the right compressor 600. Then, the control unit 7 advances the control process to step S201. After that, the control process after step S201 is repeated.

[0241] Note that the process of returning from step S201 via step S211 to step S201 is a process performed by the control unit 7 in a situation where the left cooling device 5 and the right cooling device 6 are operating normally.

[0242] Next, in step S212 of FIG. 8, the control unit 7 determines whether or not a predetermined time (for example, 3 hours) has elapsed since the start of the differential control of the compressor in step S209.

[0243] When the control unit 7 determines that a predetermined time (for example, 3 hours) has elapsed since the start of the differential control of the compressor ( "YES" in step S212), the control process proceeds to step S213.

[0244] On the other hand, when the control unit 7 determines that a predetermined time (for example, 3 hours) has not elapsed since the start of the differential control of the compressor ( "NO" in step S212), the control process proceeds to step S210.

[0245] The control unit 7 repeats steps S210 and S212 until a predetermined time elapses since the start of the differential control of the compressor in step S209 (that is, until it becomes "YES" in step S212).

[0246] Next, in step S213 of FIG. 8, the control unit 7 determines whether or not the left cooling device 5 and the right cooling device 6 are malfunctioning.

[0247] The situation in which step S213 is executed is a situation where a predetermined time has elapsed since the compressor operation control was started in step S209 and the temperature inside the warehouse has not reached the set temperature. Such a situation may indicate that one of the left cooling device 5 and the right cooling device 6 is malfunctioning.

[0248] When the execution status of the defrosting operation satisfies the second failure condition, the control unit 7 determines that one of the left cooling device 5 and the right cooling device 6 is malfunctioning.

[0249] The second failure condition is that in step S206, after one of the left evaporator 503 and the right evaporator 603 has performed a defrosting operation, the other of the left evaporator 503 and the right evaporator 603 is performing a defrosting operation.

[0250] That is, the second failure condition is a situation where the left evaporator 503 and the right evaporator 603 alternately perform defrosting operations at the time when step S213 is executed.

[0251] In a situation where the left evaporator 503 and the right evaporator 603 alternately perform defrosting operations, it is highly likely that no frost is attached to both the left evaporator 503 and the right evaporator 603. In such a situation, if the temperature inside the warehouse has not reached the set temperature, it is highly likely that one of the left cooling device 5 and the right cooling device 6 is malfunctioning.

[0252] Specifically, when the execution status of the defrosting operation satisfies the second failure condition, the control unit 7 compares the detected value of the left first temperature detection unit 51 with the detected value of the right first temperature detection unit 61, and identifies the cooling device having the evaporator with the higher temperature as the malfunctioning cooling device (hereinafter referred to as the second failure cooling device).

[0253] When the detected value of the left first temperature detection unit 51 is higher than the detected value of the right first temperature detection unit 61, the control unit 7 specifies the left cooling device 5 as the second failure cooling device.

[0254] Also, when the detected value of the right first temperature detection unit 61 is higher than the detected value of the left first temperature detection unit 51, the control unit 7 specifies the right cooling device 6 as the second failure cooling device.

[0255] When the control unit 7 determines that one of the left cooling device 5 and the right cooling device 6 has failed ( "YES" in step S213), the control process proceeds to step S214.

[0256] On the other hand, when the control unit 7 determines that the left cooling device 5 and the right cooling device 6 have not failed (i.e., are normal) ( "NO" in step S213), the control process proceeds to step S204. Then, the control unit 7 repeats the control process after step S204.

[0257] Also, in step S214 of FIG. 8, the control unit 7 notifies information indicating that the cooling device specified as the second failure cooling device in step S213 has failed.

[0258] The control unit 7 may display information indicating that the second failure cooling device has failed on the display unit of the control panel 23 (see FIG. 1). After that, the control unit 7 ends the control process at an appropriate timing.

[0259] Note that the notification method is not particularly limited. The notification method may be light or sound (e.g., voice). Also, the control unit 7 may transmit information indicating that the target evaporator has failed to an external terminal communicatively connected to the refrigeration device 1.

[0260] The defrost control performed by the control unit 7 has been described above. The control unit 7 repeatedly performs the control process shown in FIG. 8 while the compressor operation control is being performed.

[0261] (Operation and Effect of the Present Embodiment) According to the refrigeration device 1 of the present embodiment having the above-described configuration, failures of the left cooling device 5 and the right cooling device 6 can be detected. The reason for this will be explained.

[0262] First, the refrigeration device 1 of the present embodiment performs first failure determination control and cooling device determination control in the cooling device determination control shown in FIG. 7.

[0263] The refrigeration device 1 can detect failures of the left cooling device 5 and the right cooling device 6 by the first failure determination control. Also, the refrigeration device 1 can detect a cooling device with deteriorated cooling performance among the left cooling device 5 and the right cooling device 6 by the cooling device determination control.

[0264] Furthermore, the refrigeration device 1 of the present embodiment performs second failure determination control in the defrosting control shown in FIG. 8. The refrigeration device 1 can detect failures of the left cooling device 5 and the right cooling device 6 by the second failure determination control. In addition, the operation and effect obtained from the refrigeration device 1 of the present embodiment are as described above.

[0265] [Appendix] As described above, the refrigeration device 1 of the present embodiment (specifically, the control unit 7) has a function of performing second failure determination control in the defrosting control shown in FIG. 8.

[0266] A refrigeration device according to an example of a reference example having such a function is a first cooling device having a first evaporator, a second cooling device having a second evaporator, and a control unit that performs defrosting control for controlling the defrosting operations of the first evaporator and the second evaporator, and the control unit determines failures of the first cooling device and the second cooling device based on the implementation status of the defrosting operation in the defrosting control.

[0267] The refrigeration device according to such a reference example may or may not have a function of performing the cooling device determination control (specifically, the first failure determination control and the cooling capacity determination control) shown in FIG. 7.

[0268] When implementing the refrigeration device according to the above reference example, specifically, When one of the first evaporator and the second evaporator has performed a defrosting operation continuously for a predetermined number of times, the control unit determines that the cooling device having the other evaporator among the first cooling device and the second cooling device is malfunctioning.

[0269] When implementing the refrigeration device according to the above reference example, specifically, When the first evaporator and the second evaporator alternately perform a defrosting operation and the temperature inside the storage does not reach the set temperature even after a predetermined time has elapsed, the control unit determines that either one of the first cooling device and the second cooling device is malfunctioning.

[0270] When implementing the above refrigeration device, specifically, The control unit determines that the cooling device having the evaporator with the higher temperature among the first evaporator and the second evaporator is malfunctioning.

[0271] In addition, when implementing the refrigeration device according to the present invention, the refrigeration device does not necessarily need to include all of the above configurations. Within a technically non - contradictory range, the configurations included in the refrigeration device may be appropriately selected.

Industrial Applicability

[0272] The present invention can be applied to various refrigeration devices.

Explanation of Signs

[0273] 1 Refrigeration device 2 Main body 21 Box body 210 Opening 211 Column part 212 Top plate part 213 Rear plate part 213a Left cover 213b Right cover 214 Left plate part 215 Right plate part 216 Bottom plate part 217 Storage Room 217a Left Region 217b Right Region 218a Left Cooling Space 218b Right Cooling Space 22 Door Portion 220 Left Door 221 Right Door 23 Control Panel 3 Machine Storage Section 4 Cooling Device 5 Left Cooling Device 50 Left Refrigeration Circuit 500 Left Compressor 501 Left Condenser 502 Left Decompressor 503 Left Evaporator 51 Left First Temperature Detection Section 52 Left Second Temperature Detection Section 53 Left Blower 54 Left Heater 6 Right Cooling Device 60 Right Refrigeration Circuit 600 Right Compressor 601 Right Condenser 602 Right Decompressor 603 Right Evaporator 61 Right First Temperature Detection Section 62 Right Second Temperature Detection Section 63 Right Blower 64 Right Heater 7 Control Section

Claims

1. A first cooling device having a first evaporator; A second cooling device having a second evaporator; A first detection unit for detecting the temperature of the first evaporator; A second detection unit for detecting the temperature of the second evaporator; A control unit that performs cooling device determination control for determining the status of the first cooling device and the second cooling device based on the difference between a first detection value of the first detection unit and a second detection value of the second detection unit. A refrigeration device.

2. The first cooling device has a first compressor that repeats a cycle operation including an ON state and an OFF state; The second cooling device has a second compressor that repeats a cycle operation including an ON state and an OFF state; The first compressor and the second compressor operate differentially; In the cooling device determination control, the control unit Determines that the first cooling device is faulty when the difference is always positive in one cycle operation of the first compressor; Determines that the second cooling device is faulty when the difference is always negative in the one cycle operation. The refrigeration device according to claim 1.

3. In the cooling device determination control, when the control unit detects a failure of the same cooling device twice in a row, it notifies that a failure has occurred. The refrigeration device according to claim 2.

4. The first cooling device has a first compressor that repeats a cycle operation including an ON state and an OFF state; The second cooling device has a second compressor that repeats a cycle operation including an ON state and an OFF state; The first compressor and the second compressor operate differentially; In the cooling device determination control, the control unit performs cooling capacity determination control for determining the status of the cooling capacities of the first cooling device and the second cooling device based on the average value of the differences in one cycle operation of the first compressor. The refrigeration device according to claim 1.

5. In the cooling capacity determination control, the control unit Determines that the capacity of the first cooling device has decreased when the average value is greater than a first threshold value; Determines that the capacity of the second cooling device has decreased when the average value is less than a second threshold value. The refrigeration device according to claim 4.

6. The first threshold value and the second threshold value are preset values according to the model of the refrigeration device. The refrigeration device according to claim 5.

7. At least one of the first threshold value and the second threshold value is a value determined based on a function preset according to the model of the refrigeration device and the difference between the temperature inside the storage compartment and the set temperature. The refrigeration device according to claim 5.

8. When the difference between the outside air temperature and the set temperature is greater than a predetermined value, the control unit performs the cooling capacity determination control. The refrigeration device according to claim 4.

9. The first cooling device has a first compressor that repeats a cycle operation including an ON state and an OFF state. The second cooling device has a second compressor that repeats a cycle operation including an ON state and an OFF state. When the door is opened, when the set temperature inside the storage compartment is changed, when the rotational speeds of the first compressor and the second compressor change, or when defrost control for removing frost from the first evaporator or the second evaporator is executed, the control unit does not perform the cooling device determination control until the first compressor performs the cycle operation a predetermined number of times. The refrigeration device according to claim 1.

10. The first cooling device cools the left region of the storage compartment. The second cooling device cools the right region of the storage compartment. The first evaporator is provided behind the left region. The second evaporator is provided behind the right region. The first detection unit is fixed to the first evaporator. The second detection unit is fixed to the second evaporator. The refrigeration device according to claim 1.

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