Cooling device

Abstract

To provide a cooling device capable of supplying a refrigerant to each of a plurality of evaporators individually even when cooling a plurality of cooling chambers by using a compressor in common for the plurality of evaporators.SOLUTION: A cooling device 100 includes: a common compressor 1 that is provided in common for a first evaporator 12 and a second evaporator 22 and compresses a refrigerant; a first control section 3 that controls the common compressor 1 and a first expansion valve 11; and a second control section 4 that controls a second expansion valve 21. The first control section 3 acquires control information on whether or not temperature control using the second expansion valve 21 is being performed at least from the second control section 4 through communications. When acquiring the control information indicating that the temperature control using the second expansion valve 21 is being performed from the second control section 4, the first control section 3 performs control for operating the common compressor 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known an apparatus that uses an evaporator to cool a plurality of cooling chambers (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a configuration in which a partition is provided in the center of a cooling case with an open top, thereby dividing the cooling chamber into two. The above-mentioned Patent Document 1 also discloses a configuration in which a cooling circuit connected to one refrigerator condensing unit including a compressor that compresses the refrigerant is branched using a branch pipe, thereby supplying equal amounts of refrigerant to each of two evaporators provided in each cooling chamber. In this way, the above-mentioned Patent Document 1 cools two cooling chambers with a simple configuration using one refrigerator condensing unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 60-079678 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the cooling device described in the above Patent Document 1, no specific control means is disclosed, and the same amount of refrigerant is simply branched and supplied to the two evaporators using a branch pipe, so it is considered that the refrigerant supplied to the two evaporators is not individually controlled. In this case, when the amount of heat leaking to the outside differs in the two cooling chambers, the temperature of one cooling chamber becomes high and the temperature of the other cooling chamber becomes low, making it difficult to manage the product at a desired temperature. Furthermore, when the compressor is stopped in one cooling chamber to defrost, there is a problem that the supply of refrigerant to the evaporator provided in the other cooling chamber is also stopped. Therefore, even when a common compressor is used to cool multiple cooling chambers, a cooling device capable of supplying refrigerant individually to each of the multiple evaporators is desired.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a cooling device that is capable of supplying refrigerant individually to each of multiple evaporators, even when a common compressor for the multiple evaporators is used to cool multiple cooling chambers. [Means for solving the problem]

[0007] A cooling device according to a first aspect of the present invention includes a first evaporator provided in a first cooling chamber and evaporating a refrigerant, a second evaporator provided in a second cooling chamber and evaporating the refrigerant, a first expansion valve provided in the first evaporator and expanding the refrigerant and adjusting the amount of refrigerant supplied to the first evaporator, a second expansion valve provided in the second evaporator and expanding the refrigerant and adjusting the amount of refrigerant supplied to the second evaporator, a common compressor provided in common to the first evaporator and the second evaporator and compressing the refrigerant, a first control unit that controls the common compressor and the first expansion valve, and a second control unit that controls the second expansion valve, wherein the first control unit is configured to acquire control information regarding whether or not temperature control is being performed using the second expansion valve from at least the second control unit via communication, and when the first control unit acquires control information indicating that temperature control is being performed using the second expansion valve from the second control unit, control the common compressor to operate.

[0008] The cooling device according to the first aspect of the present invention includes a first control unit that controls the common compressor and the first expansion valve, and a second control unit that controls the second expansion valve, as described above. As a result, the first control unit and the second control unit each control the first expansion valve and the second expansion valve, and therefore the amount of refrigerant supplied to each of the first evaporator and the second evaporator can be controlled. In addition, in the cooling device according to the first aspect of the present invention, the first control unit is configured to acquire control information regarding whether or not temperature control using the second expansion valve is being performed from at least the second control unit through communication, and when the first control unit acquires control information indicating that temperature control using the second expansion valve is being performed from the second control unit, the first control unit is configured to control the common compressor to operate. As a result, even when it is not necessary to operate the common compressor for the first evaporator, the first control unit can operate the common compressor based on the control information regarding whether or not temperature control using the second expansion valve is being performed by acquiring control information from the second control unit through communication. In other words, regardless of whether or not it is necessary to operate the common compressor for the first evaporator, the first control unit can operate the common compressor for the second evaporator to supply refrigerant to the second evaporator. As a result, even when a common compressor for the multiple evaporators is used to cool multiple cooling chambers, the refrigerant can be supplied individually to each of the multiple evaporators.

[0009] In the cooling device according to the first aspect, the first control unit is preferably configured to control the common compressor to operate when the first expansion valve is in a closed state and control information indicating that temperature control is being performed using the second expansion valve is acquired from the second control unit. With this configuration, even when the first expansion valve is closed to stop the refrigerant being supplied to the first evaporator, the first control unit can operate the common compressor to supply the refrigerant to the second evaporator.

[0010] In this case, preferably, the first control unit is configured to control the common compressor to continue operation when the first expansion valve is in a closed state and the control information indicating that temperature control using the second expansion valve is being performed is continuously acquired from the second control unit, and to control the common compressor to start operation when the first expansion valve is in a closed state and the control information indicating that temperature control using the second expansion valve is being performed is acquired from the second control unit after acquiring control information indicating that temperature control using the second expansion valve is not being performed from the second control unit. With this configuration, the first control unit can appropriately control the operation of the common compressor so as to supply refrigerant to the second evaporator based on the control information regarding whether or not temperature control using the second expansion valve is being performed, acquired by communication.

[0011] In the cooling device according to the first aspect, each of the first control unit and the second control unit is preferably configured to output a control signal for controlling the adjustment of the opening degree of the first expansion valve or the second expansion valve, and the first control unit is configured to control the common compressor so that the temperature of the first cooling chamber approaches the temperature of the second cooling chamber based on a priority indoor temperature, which is the higher indoor temperature of the first cooling chamber in which the first evaporator corresponding to the first expansion valve to which the control signal indicating the open state is input, or the second cooling chamber in which the second evaporator corresponding to the second expansion valve to which the control signal indicating the open state is input. With this configuration, the common compressor is controlled based on the higher indoor temperature of the cooling chambers in which the expansion valve is open and the temperature is controlled, so that the rotation speed of the common compressor can be reduced and the load on the common compressor can be reduced. As a result, the cooling chambers can be cooled while suppressing power consumption.

[0012] In this case, preferably, the first control unit is configured to output a control signal for adjusting the opening degree of the first expansion valve based on the room temperature of the first cooling chamber in which the first evaporator corresponding to the first expansion valve is provided when communication with the second control unit is not possible, and the second control unit is configured to output a control signal for adjusting the opening degree of the second expansion valve based on the room temperature of the second cooling chamber in which the second evaporator corresponding to the second expansion valve is provided when communication with the first control unit is not possible. With this configuration, even when the first control unit and the second control unit cannot communicate with each other due to a power outage or a disconnection of the communication line, each of the first control unit and the second control unit can control the temperature of the first cooling chamber and the second cooling chamber. As a result, even when a power outage or a disconnection of the communication line occurs, the temperatures of the multiple cooling chambers can be individually controlled.

[0013] In this case, the first and second expansion valves are preferably structured to maintain the opening degree at the time when power supply was last stopped when the power supply is stopped. With this configuration, the first and second expansion valves do not close even during a power outage, so that it is possible to prevent the cooling circuit from being blocked and the temperatures in the first and second cooling chambers from rising.

[0014] In the cooling device according to the first aspect, the second control unit is preferably configured to control the second expansion valve to open when communication with the first control unit is not possible. With this configuration, when the common compressor is operating and the first expansion valve is fully closed, it is possible to prevent the second expansion valve from also being fully closed, which would result in blockage of the cooling circuit. As a result, it is possible to reduce the risk of failure of the cooling device due to a pressure rise in the cooling circuit.

[0015] In this case, the second control unit is preferably configured to control the second expansion valve to continue to be open at least until a predetermined standby time has elapsed when communication with the first control unit is no longer possible. With this configuration, even if communication between the first control unit and the second control unit is not immediately restored, blocking of the cooling circuit can be suppressed at least until the predetermined standby time has elapsed.

[0016] In the cooling device in which the second control unit opens the second expansion valve when communication with the first control unit is no longer possible, the second control unit is preferably configured to control the opening degree of the second expansion valve when communication with the first control unit is no longer possible when the cooling device is powered on to be smaller than the opening degree of the second expansion valve when communication with the first control unit is no longer possible when cooling is stopped. With this configuration, it is possible to suppress abrupt pressure fluctuations even when powering on the cooling device, which is more likely to occur due to the common compressor being switched from a stopped state to an operating state, than when cooling is stopped.

[0017] In this case, preferably, the second control unit is configured to control the second expansion valve to adjust the opening degree corresponding to the operation mode that was scheduled to be performed when communication with the first control unit is possible when a pressure equilibrium time for bringing the pressures of the first and second cooling chambers closer to a balanced state has elapsed or when communication with the first control unit is restored, in the case where communication with the first control unit is possible when communication with the first control unit is possible when communication with the first control unit is possible. With this configuration, the operation mode that was scheduled to be performed is started in a state where the pressures of the first and second cooling chambers are balanced, so that it is possible to suppress the occurrence of refrigerant imbalance and operation failure due to variations in the pressure of the refrigerant in the cooling circuit.

[0018] In the cooling device in which the opening degree of the second expansion valve when power is turned on is made smaller than the opening degree of the second expansion valve when cooling is stopped, the second control unit is preferably configured to control the second expansion valve to be fully open for a pressure equilibrium time for bringing the pressures in the first and second cooling chambers closer to a balanced state when communication with the first control unit is not possible when cooling is stopped in the cooling device. With this configuration, the pressures in the first and second cooling chambers can be brought closer to a balanced state in a shorter time than when the second expansion valve is opened at a small opening degree.

[0019] In this case, the second control unit is preferably configured to control the second expansion valve to be fully closed if communication with the first control unit is not possible when cooling is stopped by the cooling device, after the pressure equilibrium time has elapsed, even if the state in which communication with the first control unit is not possible continues. With this configuration, the pressures in the first and second cooling chambers can be brought close to a balanced state in a short time, so that the generation of residual pressure in the cooling circuit can be suppressed even if the second expansion valve is fully closed before communication with the first control unit is possible.

[0020] In the cooling device that performs control to fully open the second expansion valve during the pressure equilibrium time, the second control unit is preferably configured to perform control to open the second expansion valve at a smaller opening than the fully open state when communication with the first control unit is not possible when cooling of the cooling device is stopped and after the pressure equilibrium time has elapsed, the second control unit acquires control information from the first control unit indicating that temperature control using the first expansion valve is not being performed and control information indicating that the common compressor is operating. With this configuration, even if the common compressor continues to operate and the first expansion valve becomes fully closed before the second expansion valve, the second expansion valve is open, so that blocking of the cooling circuit can be suppressed.

[0021] In the cooling device according to the first aspect, the first and second cooling chambers are preferably arranged adjacent to each other, and the common compressor is arranged in a housing including the first and second cooling chambers. With this configuration, the first and second cooling chambers and the common compressor can be arranged close to each other. As a result, the cooling device can be made compact. Effect of the Invention

[0022] According to the present invention, as described above, a cooling device can be provided that is capable of supplying refrigerant individually to each of multiple evaporators, even when multiple cooling chambers are cooled using a compressor common to multiple evaporators. [Brief description of the drawings]

[0023] [Figure 1] 1 is a diagram showing a configuration of a cooling system including a cooling device according to an embodiment of the present invention. [Diagram 2] 4 is a diagram for explaining the operating state of the common compressor when the first control unit performs control to close the first expansion valve according to one embodiment of the present invention. FIG. [Diagram 3] 10 is a diagram for explaining the operating state of the common compressor when the second control unit controls the second expansion valve to open from a closed state according to an embodiment of the present invention. FIG. [Figure 4] FIG. 11 is a flow diagram of control performed by a second control unit when a communication failure occurs when the cooling device is powered on, according to an embodiment of the present invention. [Diagram 5] 10 is a diagram illustrating a change in the opening degree of the second expansion valve when a communication failure occurs when the cooling device is turned on according to an embodiment of the present invention. FIG. [Figure 6] FIG. 11 is a flow diagram of control performed by a second control unit in the case where a communication failure occurs when cooling is stopped by a cooling device according to an embodiment of the present invention. [Figure 7] 10 is a diagram illustrating control for fully closing the second expansion valve in a case where a communication failure occurs when cooling is stopped in a cooling device according to an embodiment of the present invention. FIG. [Figure 8] 10 is a diagram illustrating control for adjusting the second expansion valve to an initial opening degree in a case where a communication failure occurs when cooling of a cooling device is stopped according to an embodiment of the present invention. FIG. [Figure 9] FIG. 13 is a diagram showing a configuration of a cooling system according to a modified example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] The configuration of a cooling system 110 according to one embodiment will be described with reference to FIG.

[0026] (Device configuration of cooling system 110) In this embodiment, the cooling system 110 includes a cooling device 100 including a common compressor 1, a condenser 2, a first control unit 3, a second control unit 4, a first expansion valve 11, a second expansion valve 21, a first evaporator 12, and a second evaporator 22, a display unit 5, a first cooling chamber 10, and a second cooling chamber 20. The cooling system 110 is configured to cool the first cooling chamber 10 and the second cooling chamber 20 by circulating a refrigerant. The first cooling chamber 10 and the second cooling chamber 20 are connected in parallel to each other in a cooling circuit C1 in which the refrigerant of the cooling system 110 circulates. The cooling system 110 is used, for example, as a showcase.

[0027] As shown in FIG. 1, the cooling system 110 includes a common compressor 1. The common compressor 1 is configured to compress a refrigerant. The common compressor 1 is controlled by an inverter (not shown). As a result, the common compressor 1 is configured to be able to adjust the flow rate of the refrigerant discharged from the common compressor 1. The refrigerant is, for example, R410A, R404A, R32, or carbon dioxide (CO2). The common compressor 1 is provided in common to the first evaporator 12 and the second evaporator 22 provided in the first cooling chamber 10 and the second cooling chamber 20, respectively. In this embodiment, the common compressor 1 is provided in a housing (not shown) in which the first cooling chamber 10 and the second cooling chamber 20 are provided.

[0028] The cooling system 110 also includes a condenser 2. The condenser 2 is a so-called external heat exchanger. The condenser 2 is configured to condense the refrigerant discharged from the common compressor 1. The condenser 2 is provided with a blower 2a and configured to send air to the condenser 2. Heat is then transferred from the refrigerant in the condenser 2 to the air sent by the blower 2a, and the heat of the refrigerant is removed.

[0029] The cooling system 110 also includes a first cooling compartment 10 and a second cooling compartment 20. The first cooling compartment 10 and the second cooling compartment 20 are independent of each other and are disposed adjacent to each other. The first cooling compartment 10 and the second cooling compartment 20 each have products M cooled therein and are provided with doors (not shown) through which users can insert and remove the products M. As a result, the first cooling compartment 10 and the second cooling compartment 20 may have different doors open for different periods depending on the usage situation of the user, and therefore the amount of heat leakage (the amount of heat leaking to the outside) of the first cooling compartment 10 and the amount of heat leakage of the second cooling compartment 20 may differ.

[0030] The cooling system 110 also includes a first expansion valve 11 and a second expansion valve 21. The first expansion valve 11 and the second expansion valve 21 are configured to expand the refrigerant condensed by the condenser 2. In this embodiment, the first expansion valve 11 and the second expansion valve 21 are electronic expansion valves operated by a stepping motor (not shown). The openings of the first expansion valve 11 and the second expansion valve 21 are adjusted to adjust the amount of refrigerant supplied to the first evaporator 12 and the second evaporator 22 provided downstream of the cooling circuit C1. The openings of the first expansion valve 11 and the second expansion valve 21 are adjusted by the stepping motor that receives a control command output from the first control unit 3 and the second control unit 4.

[0031] In this embodiment, when the supply of power to the first expansion valve 11 and the second expansion valve 21 is stopped due to a power outage, for example, the first expansion valve 11 and the second expansion valve 21 are structured to maintain the opening degree at the time when power was last supplied. Furthermore, when power is restored, the first expansion valve 11 and the second expansion valve 21 are operated in the origin direction (the direction in which the valve closes) by the stepping motor to reset the origin position related to the opening and closing of the valve.

[0032] The cooling system 110 also includes a first evaporator 12 and a second evaporator 22. The first evaporator 12 and the second evaporator 22 are configured to evaporate the refrigerant expanded by the first expansion valve 11 and the second expansion valve 21, respectively. The first evaporator 12 and the second evaporator 22 are provided in parallel with each other. The first evaporator 12 and the second evaporator 22 also include an internal fan 12a and an internal fan 22a, respectively. In the first evaporator 12 and the second evaporator 22, heat of the refrigerant is removed by air sent from the internal fan 12a and the internal fan 22a to the main body of the first evaporator 12 and the second evaporator 22, respectively.

[0033] The cooling system 110 also includes a cooling room internal temperature sensor 13 and a cooling room internal temperature sensor 23. The cooling room internal temperature sensor 13 measures the internal temperature of the first cooling room 10. The cooling room internal temperature sensor 23 measures the internal temperature of the second cooling room 20.

[0034] The cooling system 110 also includes a first control unit 3 and a second control unit 4. The first control unit 3 and the second control unit 4 each have a processor such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a GPU (Graphics Processing Unit), which are not shown. Here, in this embodiment, the first control unit 3 is configured to control the common compressor 1 and the first expansion valve 11. The second control unit 4 is configured to control the second expansion valve 21, but not to control the common compressor 1.

[0035] In this embodiment, the first control unit 3 and the second control unit 4 are connected by, for example, serial communication wiring conforming to the RS-232C standard, and obtain each other's control information through serial communication. Specifically, the first control unit 3 obtains control information related to the operating status (open / closed state) of the second expansion valve 21 controlled by the second control unit 4, and the second control unit 4 obtains control information related to the operating status (open / closed state) of the first expansion valve 11 controlled by the first control unit 3 and the operating status of the common compressor 1 through serial communication.

[0036] In this embodiment, the first control unit 3 performs temperature control (temperature adjustment request) to adjust the opening degree of the first expansion valve 11 based on the indoor temperature of the first cooling chamber 10. Specifically, the first control unit 3 performs control to adjust the opening degree of the first expansion valve 11 so as to adjust the temperature of the first cooling chamber 10 according to the "degree of superheat" based on the temperature of the supply side and the temperature of the discharge side of the first evaporator 12 installed in the first cooling chamber 10. Similarly, the second control unit 4 performs temperature control (temperature adjustment request) to adjust the opening degree of the second expansion valve 21 based on the indoor temperature of the second cooling chamber 20.

[0037] In addition, the first control unit 3 acquires the cooling chamber temperature of the second cooling chamber 20 by serial communication with the second control unit 4. In this embodiment, the first control unit 3 determines the rotation speed of the common compressor 1 based on the priority chamber temperature, which is the higher temperature of the temperature of the first cooling chamber 10 and the temperature of the second cooling chamber 20, and outputs a control command to the inverter to control the common compressor 1. For example, in this embodiment, since the temperature of the second cooling chamber 20 is higher than the temperature of the first cooling chamber 10, the first control unit 3 determines the rotation speed of the common compressor 1 so as to bring the temperature of the first cooling chamber 10 closer to the temperature of the second cooling chamber 20.

[0038] Moreover, in this embodiment, the cooling system 110 includes a display unit 5. The display unit 5 is, for example, a liquid crystal monitor, and displays error information from the first control unit 3 and the second control unit 4, and information such as the operating status of the common compressor 1.

[0039] (Method of controlling cooling device 100) Next, an example of a method for controlling the cooling device 100 will be described with reference to FIGS.

[0040] In this embodiment, the first control unit 3 generates control information that indicates, for example, "1" when the common compressor 1 is in operation and "0" when the common compressor 1 is stopped. The first control unit 3 generates control information that indicates "1" when a temperature adjustment request is made using the first expansion valve 11 and the first expansion valve 11 is in an open state regardless of the opening degree, and generates control information that indicates "0" when a temperature adjustment request is not made and the first expansion valve 11 is in a closed state. The second control unit 4 generates control information that indicates "1" when a temperature adjustment request is made using the second expansion valve 21 and the second expansion valve 21 is in an open state regardless of the opening degree, and generates control information that indicates "0" when a temperature adjustment request is not made and the second expansion valve 21 is in a closed state. As shown in FIG. 2, at a time before time t1, the common compressor 1 in the cooling system 110 is in an operation state, and the first expansion valve 11 and the second expansion valve 21 are in a state where control is being performed based on a temperature adjustment request.

[0041] At this time, the first control unit 3 performs control based on a temperature adjustment request by issuing a control signal to adjust the opening of the first expansion valve 11 based on the temperature (superheat) of the first cooling chamber 10 as an adjustment step. Similarly, the second control unit 4 performs control based on a temperature adjustment request by issuing a control signal to adjust the opening of the second expansion valve 21 based on the temperature (superheat) of the second cooling chamber 20 as an adjustment step.

[0042] Here, a case will be described in which the first control unit 3 stops the temperature adjustment request and closes the first expansion valve 11 for defrosting at time t1. The first control unit 3 performs serial communication with the second control unit 4 to acquire control information "1" generated by the second control unit 4 at time t1, which indicates that a temperature adjustment request is being made using the second expansion valve 21. As a result, the first control unit 3 controls the common compressor 1 so as to continue operation of the common compressor 1 as an operation step.

[0043] Then, at time t2, it is assumed that the second control unit 4 closes the second expansion valve 21 for defrosting. At this time, the first control unit 3 acquires the control information "0" generated by the second control unit 4 at time t2, which indicates that the temperature adjustment request is not made using the second expansion valve 21, by performing serial communication with the second control unit 4. As a result, the first control unit 3 can detect that both the first expansion valve 11 and the second expansion valve 21 are closed and that the temperature adjustment request is not made by both the first control unit 3 and the second control unit 4, and therefore controls the common compressor 1 so as to stop the operation of the common compressor 1 at time t3. Note that the time between time t2, when it is detected that both the first expansion valve 11 and the second expansion valve 21 are closed and that the temperature adjustment request is not made by both the first control unit 3 and the second control unit 4, and time t3, when the operation of the common compressor 1 is stopped, can be set arbitrarily.

[0044] Next, as shown in FIG. 3, a case will be described in which, at a time prior to time t11, the common compressor 1 in the cooling system 110 is not operating, the first expansion valve 11 and the second expansion valve 21 are closed, and no temperature control request is made, and then the second control unit 4 opens the second expansion valve 21 and starts a temperature control request.

[0045] First, at time t11, the second control unit 4 opens the second expansion valve 21 upon completion of defrosting, and starts a temperature adjustment request. At this time, the first control unit 3 acquires control information "1" indicating that a temperature adjustment request is being made using the second expansion valve 21 at time t11, generated by the second control unit 4, by performing serial communication with the second control unit 4. As a result, the first control unit 3 controls the common compressor 1 so as to start operation of the common compressor 1, and at time t12, operation of the common compressor 1 starts. After that, during the time period from time t12 to time t13, the first control unit 3 continues to acquire "1" indicating that a temperature adjustment request is being made using the second expansion valve 21, generated by the second control unit 4, and therefore continues operation of the common compressor 1 as an operation step.

[0046] Here, a case will be described in which, at time t13, the first control unit 3 opens the first expansion valve 11 and starts a temperature adjustment request as the defrosting ends, and an electrical trouble occurs in the second control unit 4, the first control unit 3 cannot communicate with the second control unit 4, and power is no longer supplied to the second expansion valve 21. At this time, the power supply to the second expansion valve 21 is cut off, but the second expansion valve 21 continues to be open after time t13 in order to maintain the opening degree at the time t13 when power was last supplied. Since the first control unit 3 cannot serially communicate with the second control unit 4, it cannot obtain control information regarding opening and closing from the second expansion valve 21 after time t13, but the first control unit 3 is performing control based on the temperature adjustment request, so the operation control of the common compressor 1 continues.

[0047] Thereafter, at time t14, the first control unit 3 stops the temperature adjustment request again, and the second control unit 4 recovers from the abnormal state. When power is supplied to the second expansion valve 21 at time t14, the second expansion valve 21 operates to close the valve at time t14 in order to reset the opening degree to the origin. At this time, the first control unit 3 acquires control information "0" generated by the second control unit 4 at time t14, which indicates that the temperature adjustment request is not made using the second expansion valve 21, by performing serial communication with the second control unit 4. As a result, the first control unit 3 detects that both the first expansion valve 11 and the second expansion valve 21 are closed and no temperature adjustment request is made, and therefore controls the common compressor 1 as an operation step to stop the operation of the common compressor 1 at time t14. Thereafter, the operation of the common compressor 1 stops at time t15.

[0048] Next, at time t16, the second control unit 4 opens the second expansion valve 21 again and resumes the temperature adjustment request for the second cooling chamber 20. At this time, the first control unit 3 acquires control information "1" indicating that the temperature adjustment request is being made using the second expansion valve 21 at time t16 by performing serial communication with the second control unit 4. As a result, the first control unit 3 is able to detect that the second expansion valve 21 is open and making a temperature adjustment request, and therefore controls the common compressor 1 as an operation step to start the operation of the common compressor 1 at time t16. Thereafter, the operation of the common compressor 1 starts at time t17.

[0049] By using the control method of the cooling device 100 as described above, the first control unit 3 communicates with the second control unit 4 to obtain control information regarding whether or not a temperature adjustment request is being made using the second expansion valve 21, so that it is possible to operate the common compressor 1 as necessary even when the first expansion valve 11 is closed.

[0050] (When the first control unit 3 and the second control unit 4 cannot communicate with each other) 4 to 8, the control of the second expansion valve 21 by the second control unit 4 in the case where communication between the first control unit 3 and the second control unit 4 is interrupted (an abnormality occurs in communication) when the cooling device 100 shown in Fig. 1 is turned on and when cooling of the second cooling compartment 20 or the like is stopped will be described in detail. Note that the case where cooling is stopped includes, for example, a case where a defrosting operation is performed and a case where an operator or the like performs an operation stop process.

[0051] First, a case where communication between the first control unit 3 and the second control unit 4 is interrupted when the cooling device 100 is started will be described with reference to Fig. 4 and Fig. 5. The flow diagram shown in Fig. 4 is a flow performed by the second control unit 4 after the cooling device 100 is started.

[0052] 4, the second control unit 4 first performs processing to reset the origin by moving the valve in a direction to fully close it as a base point determination processing for the second expansion valve 21. After the base point determination is completed, the process proceeds to step S2.

[0053] As shown in step S2, at the end of the base point determination, the second control unit 4 communicates with the first control unit 3. The first control unit 3 and the second control unit 4 continue to try to establish a communication connection at a fixed time interval of, for example, 600 ms, and this step S2 is the communication process at the first timing after the base point determination is completed. Specifically, in the time chart shown in Fig. 5, the second control unit 4 attempts to communicate with the first control unit 3 to obtain control information from the first control unit 3 at the same time that the base point determination is completed at time t21.

[0054] If the first control unit 3 and the second control unit 4 are able to communicate with each other, the process proceeds to step S3 in Fig. 4, and if communication is not possible, the process proceeds to step S4. If the process proceeds to step S3, the second control unit 4 operates as usual, and therefore a description thereof will be omitted here. In this embodiment, the second control unit 4 proceeds to the process of step S4 at time t21 shown in Fig. 5, as the second control unit 4 was unable to communicate with the first control unit 3.

[0055] In step S4, the second control unit 4 controls the second expansion valve 21 to the initial valve opening degree until the waiting time has elapsed. Here, since the second control unit 4 cannot communicate with the first control unit 3, it cannot obtain control information related to the operating status of the common compressor 1. Therefore, even if the first expansion valve 11 is closed (fully closed) and the common compressor 1 is operating, the second expansion valve 21 is controlled to be open so as not to block the cooling circuit C1. The waiting time is a time set to determine whether or not communication between the first control unit 3 and the second control unit 4 is impossible, and when the waiting time has elapsed, it is determined that communication between the first control unit 3 and the second control unit 4 is impossible. The waiting time in this embodiment is specifically the time between time t22 and time t23 shown in FIG. 5, and is, for example, a maximum of 120 seconds. The initial valve opening degree is, for example, about 40% of the opening degree when the second expansion valve 21 is fully open.

[0056] During the above-mentioned waiting time (the time from time t22 to time t23), the first control unit 3 and the second control unit 4 continue to try to establish a communication connection as in step S5, and if communication is confirmed, proceed to step S6. If the process proceeds to step S6, the second control unit 4 operates as usual, and therefore a description thereof will be omitted here. In this embodiment, since communication between the first control unit 3 and the second control unit 4 was not possible even after the above-mentioned waiting time has elapsed, the second control unit 4 performs the control of step S7.

[0057] In step S7, the second control unit 4 continues to control the second expansion valve 21 to the initial valve opening degree for at least the pressure equilibrium time following the state of step S4. Here, the pressure equilibrium time refers to the time required until the pressures of the first cooling chamber 10 and the second cooling chamber 20 are balanced (pressure equilibrium state). Specifically, the pressure equilibrium time in this embodiment is the time between time t22 and time t25 shown in Fig. 5, and is, for example, 600 seconds. The pressure equilibrium time is preset by an operator or the like to be longer than the standby time.

[0058] After the above-mentioned waiting time (the time from time t22 to time t23) has elapsed, an error code indicating that communication is not possible between the first control unit 3 and the second control unit 4 is displayed on the display unit 5. This allows an operator or the like to notice the communication abnormality and take measures to resolve the communication abnormality.

[0059] Here, at time t24, the first control unit 3 starts temperature adjustment of the first cooling chamber 10 based on the fact that the time has come when the adjustment was scheduled in advance. Therefore, the first control unit 3 starts the operation of the common compressor 1 and controls the opening degree of the first expansion valve 11 to a predetermined opening degree. However, in this embodiment, communication between the first control unit 3 and the second control unit 4 has not yet been restored even at time t24, and the second control unit 4 does not obtain the control information "1" indicating that the first control unit 3 is making a temperature adjustment request. Then, the process proceeds to step S8.

[0060] In step S8, after the above-mentioned pressure equilibrium time (the time between time t22 and time t25) has elapsed, the second control unit 4 performs control to adjust the opening degree of the second expansion valve 21 based on the operation mode that was scheduled to be performed in advance. Specifically, as shown in FIG. 5, the second control unit 4 performs control to fully close the second expansion valve 21 because the operation mode that does not request temperature adjustment, that is, the cooling stop state, is scheduled to be performed after time t25. Note that, since the pressure equilibrium time has elapsed, the pressure balance between the first cooling chamber 10 and the second cooling chamber 20 is achieved. Note that, in the operation mode that was scheduled to be performed in advance, when a temperature adjustment request is made (not shown), the second control unit 4 outputs a control signal to adjust the opening degree of the second expansion valve 21 based on the temperature of the second cooling chamber 20, for example, to PID control the opening degree of the second expansion valve 21.

[0061] As described above, even if communication between the first control unit 3 and the second control unit 4 is cut off when the cooling device 100 is turned on, the second control unit 4 can appropriately control the second expansion valve 21 to suppress blockage of the cooling circuit C1 and pressure increase.

[0062] 6 to 8, the control performed by the second control unit 4 when communication between the first control unit 3 and the second control unit 4 is interrupted (including when communication is restored after being interrupted) while cooling of the second cooling chamber 20 is stopped (during cooling stop operation) will be described. The flow diagram shown in Fig. 6 is a flow performed by the second control unit 4 when cooling of the second cooling chamber 20 is stopped by closing (fully closing) at least the second expansion valve 21.

[0063] First, the control performed by the second control unit 4 when cooling only the second cooling chamber 20 is stopped will be described with reference to FIG. 6 and FIG. 7. As in the description of the power-on of the cooling device 100, the second control unit 4 communicates with the first control unit 3 at regular time intervals even during the cooling stop operation. Here, as shown in step S11 of FIG. 6, the second control unit 4 controls the second expansion valve 21 to be fully open from the timing of stopping cooling of the second cooling chamber 20 until the pressure equilibrium time has elapsed. For example, in this embodiment, as shown in the time chart of FIG. 7, the first control unit 3 makes a temperature adjustment request and keeps the common compressor 1 operating. On the other hand, the second control unit 4 makes a temperature adjustment request until time t31 and controls the second expansion valve 21 to an opening degree according to the superheat degree, but does not perform the temperature adjustment request control after time t31. That is, in this embodiment, the process of step S11 of FIG. 6 is started at time t31.

[0064] In step S11, as described above, the second control unit 4 controls the second expansion valve 21 to be in a fully open state until the pressure equilibrium time has elapsed. The pressure equilibrium time in this embodiment refers to the time required until the pressures in the first cooling chamber 10 and the second cooling chamber 20 are balanced (pressure equilibrium state). Specifically, the pressure equilibrium time is the time between time t31 and time t33 shown in Fig. 7, and is, for example, 600 seconds.

[0065] In addition, the second control unit 4 controls the second expansion valve 21 to the fully open state until the pressure equilibrium time has elapsed, in any communication state, such as when a communication abnormality occurs with the first control unit 3 during this pressure equilibrium time, or when communication is restored after the communication abnormality occurs with the first control unit 3. This time, a case where a communication abnormality occurs between the first control unit 3 and the second control unit 4 at time t32 will be described. Even if the second control unit 4 cannot communicate with the first control unit 3 and cannot obtain control information regarding the operating status of the common compressor 1, the second control unit 4 controls the second expansion valve 21 to the fully open state, so that it is possible to prevent the blockage of the cooling circuit C1. After the pressure equilibrium time has elapsed, the process proceeds to step S12 in FIG. 6.

[0066] In step S12, if the communication with the first control unit 3 has not been restored, the second control unit 4 proceeds to processing of step S13, and if the first control unit 3 informs the second control unit 4 that communication with the first control unit 3 is possible, the second control unit 4 proceeds to processing of step S14. Here, at time t33 shown in FIG. 7, communication has not been restored, and the second control unit 4 proceeds to processing of step S13 based on the fact that communication with the first control unit 3 has not been possible.

[0067] In step S13, the second control unit 4 performs control to fully close the second expansion valve 21. Specifically, the second control unit 4 performs control to fully close the second expansion valve 21 at time t33. Note that even if the second expansion valve 21 is closed (fully closed), the pressure balance between the first cooling chamber 10 and the second cooling chamber 20 is achieved because the pressure balance time has elapsed.

[0068] Next, using Figures 6 and 8, we will explain the control performed by the second control unit 4 when communication between the first control unit 3 and the second control unit 4 is cut off when cooling of the second cooling chamber 20 is stopped (during cooling stop operation), and cooling of not only the second cooling chamber 20 but also the first cooling chamber 10 is stopped, which is a different situation from that in Figure 7.

[0069] As shown in Fig. 8, the first control unit 3 outputs a control signal "0", which indicates that the first expansion valve 11 is controlled to be fully open for pressure balance, although no temperature adjustment request is made. Meanwhile, the second control unit 4 makes a temperature adjustment request until time t41, and controls the second expansion valve 21 to an opening degree according to the degree of superheat. The first control unit 3 operates the common compressor 1 by obtaining a control signal "1" from the second control unit 4, which indicates that a temperature adjustment request is made.

[0070] Here, as shown in step S11 of Fig. 6, the second control unit 4 controls the second expansion valve 21 to be fully open until the pressure equilibrium time has elapsed. Specifically, at time t41 of Fig. 8, the second control unit 4 starts control for the cooling stop operation. That is, the second control unit 4 stops the temperature adjustment request and controls the second expansion valve 21 to be fully open for pressure equilibrium.

[0071] At time t42, the pressure equilibrium time has elapsed first on the first cooling chamber 10 side, so the first control unit 3 closes (fully closes) the first expansion valve 11. Also, here, it is assumed that a communication abnormality occurs between the first control unit 3 and the second control unit 4 at time t42, and the communication is restored between time t42 and time t43. As described above, the second control unit 4 controls the second expansion valve 21 to be in the fully open state (to maintain the fully open state) in any communication state until the pressure equilibrium time has elapsed (until time t43). After the pressure equilibrium time has elapsed, the process proceeds to step S12.

[0072] In step S12, if the second control unit 4 cannot communicate with the first control unit 3, the process proceeds to step S13, and if the second control unit 4 can communicate with the first control unit 3, the process proceeds to step S14. When the process proceeds to step S13, the full-close process is performed similar to the above-described case, and therefore a description thereof is omitted here. In this embodiment, since the communication is restored at time t43, the second control unit 4 is able to communicate with the first control unit 3. That is, the process proceeds to step S14.

[0073] In step S14, if the second control unit 4 receives control information "0" from the first control unit 3 indicating that a temperature adjustment request has not been made, the second control unit 4 performs the process of step S15, and if the second control unit 4 receives control information "1" from the first control unit 3 indicating that a temperature adjustment request has been made, the second control unit 4 performs the process of step S16. Specifically, as shown at time t43 in FIG. 8, the second control unit 4 receives control information "0" from the first control unit 3 indicating that a temperature adjustment request has not been made. That is, the second control unit 4 proceeds to the process of step S16. Note that when the process proceeds to step S15, the same full-closing process as when the process proceeds to step S13 described above is performed, and therefore a description thereof will be omitted here.

[0074] In step S16, the second control unit 4 acquires control information related to the operation status of the common compressor 1 from the first control unit 3, and proceeds to the process of step S17 if the common compressor 1 is not operating, and proceeds to the process of step S18 if the common compressor 1 is operating. Specifically, as shown at time t43, the second control unit 4 acquires control information "1" indicating that the common compressor 1 is operating from the first control unit 3. That is, proceeds to the process of step S18. Note that when proceeding to step S17, the same full-closing process as when proceeding to step S13 described above is performed, and therefore a description thereof will be omitted here.

[0075] In step S18, the second control unit 4 controls the second expansion valve 21 to a standby valve opening in order to prevent the cooling circuit C1 from being blocked during the time until the operation of the common compressor 1 is stopped. The standby valve opening is, for example, about 40% of the opening of the second expansion valve 21 when it is fully open. Thereafter, as shown at time t44, the second expansion valve 21 is closed (fully closed) as the operation of the common compressor 1 is stopped. In this manner, even if communication between the first control unit 3 and the second control unit 4 is interrupted during operation when cooling is stopped, the second control unit 4 can appropriately control the second expansion valve 21 to prevent the blocking of the cooling circuit C1 and the pressure rise.

[0076] (Effects of this embodiment) Next, the effects of this embodiment will be described.

[0077] The cooling device 100 of this embodiment includes a first evaporator 12 provided in the first cooling chamber 10 to evaporate the refrigerant, a second evaporator 22 provided in the second cooling chamber 20 to evaporate the refrigerant, a first expansion valve 11 provided in the first evaporator 12 to expand the refrigerant and adjust the amount of refrigerant supplied to the first evaporator 12, a second expansion valve 21 provided in the second evaporator 22 to expand the refrigerant and adjust the amount of refrigerant supplied to the second evaporator 22, a common compressor 1 provided in common to the first evaporator 12 and the second evaporator 22 to compress the refrigerant, a first control unit 3 to control the common compressor 1 and the first expansion valve 11, and a second control unit 4 to control the second expansion valve 21. As a result, the first control unit 3 and the second control unit 4 each control the first expansion valve 11 and the second expansion valve 21, and therefore the amount of refrigerant supplied to each of the first evaporator 12 and the second evaporator 22 can be controlled. Further, the first control unit 3 is configured to acquire control information regarding whether or not temperature control is being performed using the second expansion valve 21 from at least the second control unit 4 through communication, and when the first control unit 3 acquires control information indicating that temperature control is being performed using the second expansion valve 21 from the second control unit 4, the first control unit 3 is configured to control the common compressor 1 to operate. As a result, even when it is not necessary to operate the common compressor 1 for the first evaporator 12, the first control unit 3 can operate the common compressor 1 based on the control information regarding whether or not temperature control is being performed using the second expansion valve 21 by acquiring the control information from the second control unit 4 through communication. In other words, regardless of whether it is necessary to operate the common compressor 1 for the first evaporator 12, the first control unit 3 can operate the common compressor 1 for the second evaporator 22 to supply the refrigerant to the second evaporator 22. As a result, even when a common compressor 1 common to the first evaporator 12 and the second evaporator 22 is used to cool the first cooling chamber 10 and the second cooling chamber 20, refrigerant can be supplied individually to each of the first evaporator 12 and the second evaporator 22.

[0078] In this embodiment, the first control unit 3 is configured to control the common compressor 1 to operate when the first expansion valve 11 is in a closed state and control information indicating that temperature control is being performed using the second expansion valve 21 is acquired from the second control unit 4. This allows the first control unit 3 to operate the common compressor 1 to supply refrigerant to the second evaporator 22 even when the first expansion valve 11 is closed and the refrigerant supplied to the first evaporator 12 is stopped.

[0079] In the present embodiment, the first control unit 3 is configured to control the common compressor 1 to continue operation when the first expansion valve 11 is in a closed state and the control information indicating that the temperature control is being performed using the second expansion valve 21 is continuously acquired from the second control unit 4, and to control the common compressor 1 to start operation when the first expansion valve 11 is in a closed state and the control information indicating that the temperature control is being performed using the second expansion valve 21 is acquired from the second control unit 4 after the control information indicating that the temperature control is being performed using the second expansion valve 21 is acquired from the second control unit 4. As a result, the first control unit 3 can appropriately control the operation of the common compressor 1 so as to supply refrigerant to the second evaporator 22 based on the control information regarding whether or not the temperature control is being performed using the second expansion valve 21 acquired by communication.

[0080] In this embodiment, each of the first control unit 3 and the second control unit 4 is configured to output a control signal for controlling the adjustment of the opening degree of the first expansion valve 11 or the second expansion valve 21, and the first control unit 3 is configured to control the common compressor 1 so that the temperature of the first cooling chamber 10 and the temperature of the second cooling chamber 20 approach each other based on a priority indoor temperature, which is the higher indoor temperature of the first cooling chamber 10 in which the first evaporator 12 corresponding to the first expansion valve 11 to which the control signal indicating the open state is input, or the second cooling chamber 20 in which the second evaporator 22 corresponding to the second expansion valve 21 to which the control signal indicating the open state is input. As a result, the first expansion valve 11 and the second expansion valve 21 are in an open state, and the common compressor 1 is controlled based on the indoor temperature of the second cooling chamber 20 having the higher indoor temperature out of the first cooling chamber 10 and the second cooling chamber 20 in which the temperature control is performed, so that the rotation speed of the common compressor 1 can be reduced, and the load on the common compressor 1 can be reduced. As a result, the first cooling chamber 10 and the second cooling chamber 20 can be cooled while suppressing power consumption.

[0081] In this embodiment, the first expansion valve 11 and the second expansion valve 21 are structured to maintain the opening degree at the time when the power supply is stopped. As a result, even during a power outage, the first expansion valve 11 and the second expansion valve 21 do not close, so that it is possible to prevent the cooling circuit C1 from being blocked and the temperatures of the first cooling chamber 10 and the second cooling chamber 20 from rising.

[0082] In this embodiment, the first cooling chamber 10 and the second cooling chamber 20 are disposed adjacent to each other, and the common compressor 1 is disposed in a housing including the first cooling chamber 10 and the second cooling chamber 20. This allows the first cooling chamber 10, the second cooling chamber 20, and the common compressor 1 to be disposed close to each other. As a result, the cooling device 100 can be made compact.

[0083] In this embodiment, the second control unit 4 is configured to control the second expansion valve 21 to open when communication with the first control unit 3 becomes impossible. This makes it possible to prevent the second expansion valve 21 from being closed and blocking the cooling circuit C1 when the common compressor 1 is operating and the first expansion valve 11 is closed (fully closed). As a result, it is possible to reduce the risk of failure of the cooling device 100 due to a pressure rise in the cooling circuit C1.

[0084] Furthermore, in this embodiment, the second control unit 4 is configured to perform control to keep the second expansion valve 21 open at least until a predetermined standby time has elapsed when communication with the first control unit 3 is no longer possible. This makes it possible to prevent the cooling circuit C1 from being blocked at least until the predetermined standby time has elapsed, even if communication between the first control unit 3 and the second control unit 4 is not immediately restored.

[0085] Furthermore, in this embodiment, the second control unit 4 is configured to control the opening degree of the second expansion valve 21 when communication with the first control unit 3 is not possible when the cooling device 100 is turned on to be smaller than the opening degree of the second expansion valve 21 when communication with the first control unit 3 is not possible when cooling is stopped in the cooling device 100. This makes it possible to suppress abrupt pressure fluctuations even when power is turned on, which is more likely to occur suddenly than when cooling is stopped, as the common compressor 1 changes from a stopped state to an operating state.

[0086] In this embodiment, when the second control unit 4 is unable to communicate with the first control unit 3 when the cooling device 100 is powered on, the second control unit 4 is configured to control the second expansion valve 21 to adjust the opening degree corresponding to the operation mode that was scheduled to be performed when communication with the first control unit 3 is possible, when a pressure equilibrium time for bringing the pressures of the first cooling chamber 10 and the second cooling chamber 20 closer to a balanced state has elapsed, or when communication with the first control unit 3 is restored. As a result, the operation mode that was scheduled to be performed starts with the pressures of the first cooling chamber 10 and the second cooling chamber 20 balanced, so that it is possible to suppress the occurrence of refrigerant imbalance and operation failure due to variations in the pressure of the refrigerant in the cooling circuit C1.

[0087] Furthermore, in this embodiment, when communication with the first control unit 3 becomes impossible while cooling is stopped in the cooling device 100, the second control unit 4 is configured to control the second expansion valve 21 to be fully opened for a pressure equilibrium time for bringing the pressures in the first cooling chamber 10 and the second cooling chamber 20 closer to a balanced state. This makes it possible to bring the pressures in the first cooling chamber 10 and the second cooling chamber 20 closer to a balanced state in a shorter time than when the second expansion valve 21 is opened with a small opening.

[0088] Furthermore, in this embodiment, the second control unit 4 is configured to control the second expansion valve 21 to be fully closed if communication with the first control unit 3 becomes impossible when cooling is stopped in the cooling device 100, after the pressure equilibrium time has elapsed, even if the state in which communication with the first control unit 3 is not possible continues. This allows the pressures in the first cooling chamber 10 and the second cooling chamber 20 to approach a balanced state in a short time, so that even if the second expansion valve 21 is fully closed before communication with the first control unit 3 is possible, the generation of residual pressure in the cooling circuit C1 can be suppressed.

[0089] In this embodiment, when communication with the first control unit 3 is not possible when the cooling device 100 stops cooling and the pressure equilibration time has elapsed, the second control unit 4 is configured to control the second expansion valve 21 to open at a smaller opening than the fully open state when the control unit 4 acquires control information from the first control unit 3 indicating that temperature control using the first expansion valve 11 is not being performed and control information indicating that the common compressor 1 is operating. As a result, even when the common compressor 1 continues to operate and the first expansion valve 11 becomes fully closed before the second expansion valve 21, the second expansion valve 21 is open, so that the cooling circuit C1 can be prevented from being blocked.

[0090] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

[0091] For example, in the present embodiment, an example has been described in which the first control unit 3 controls both the common compressor 1 and the first expansion valve 11, and the second control unit 4 controls the second expansion valve 21, but the present invention is not limited to this. In the present invention, the first control unit 3 may be configured to control the first expansion valve 11, and the second control unit 4 may be configured to control both the common compressor 1 and the second expansion valve 21. Alternatively, the first control unit 3 may be configured to control the first expansion valve 11, the second control unit 4 may be configured to control the second expansion valve 21, and a control unit provided separately from the first control unit 3 and the second control unit 4 and communicating with the first control unit 3 and the second control unit 4 may be configured to control the common compressor 1.

[0092] In addition, in the present embodiment, an example of the cooling system 110 that cools two cooling chambers, the first cooling chamber 10 and the second cooling chamber 20, has been shown, but the present invention is not limited to this. In the present invention, as in the cooling system 210 shown in FIG. 9, a third cooling chamber 30 may be further provided. In that case, the third cooling chamber 30 includes a third expansion valve 31, a third evaporator 32, an internal fan 32a, and a cooling chamber temperature sensor 33, and the cooling system 210 further includes a third control unit 6 that controls the third expansion valve 31. In addition, the common compressor 1 is provided in common for the first evaporator 12 to the third evaporator 32, and the operation is controlled based on a priority internal temperature, which is the highest temperature among the cooling chamber temperatures of the first cooling chamber 10 to the third cooling chamber 30.

[0093] In the present embodiment, the first control unit 3 and the second control unit 4 are connected by wiring and communicate control information by performing serial communication, but the present invention is not limited to this. In the present invention, the first control unit 3 and the second control unit 4 may communicate wirelessly or may communicate using a public communication line.

[0094] In addition, in the present embodiment, an example has been shown in which the common compressor 1 continues to operate when the first expansion valve 11 is in a closed state and the second expansion valve 21 continues to be in an open state, but the present invention is not limited to this. In the present invention, when either the first expansion valve 11 or the second expansion valve 21 continues to be in an open state, the first control unit 3 may be configured to perform control so as to continue the operation of the common compressor 1.

[0095] In addition, in the present embodiment, an example has been shown in which, when the first expansion valve 11 is in a closed state, the first control unit 3 performs control to start the operation of the common compressor 1 when it acquires control information "0" indicating that the second expansion valve 21 is in a closed state, and then acquires control information "1" indicating that the second expansion valve 21 is in an open state, but the present invention is not limited to this. In the present invention, when the first expansion valve 11 is in a closed state and the second expansion valve 21 is in a closed state, the first control unit 3 may be configured to simultaneously perform control to start the operation of the common compressor 1 when it performs control to open the first expansion valve 11.

[0096] In the present embodiment, the first control unit 3 is configured to output a control signal for adjusting the opening degree of the first expansion valve 11 based on the priority indoor temperature, and the second control unit 4 is configured to output a control signal for adjusting the opening degree of the second expansion valve 21 based on the priority indoor temperature, but the present invention is not limited to this. In the present invention, when a malfunction occurs in communication between the first control unit 3 and the second control unit 4, the first control unit 3 may output a control signal for adjusting the opening degree of the first expansion valve 11 based on the temperature of the first cooling chamber 10, and the second control unit 4 may output a control signal for adjusting the opening degree of the second expansion valve 21 based on the temperature of the second cooling chamber 20. With this configuration, even when the first control unit 3 and the second control unit 4 cannot communicate due to a power outage or a disconnection of the communication line, each of the first control unit 3 and the second control unit 4 can control the temperature of the first cooling chamber 10 and the second cooling chamber 20. As a result, the temperatures of the multiple cooling chambers can be individually controlled even during a power outage or a disconnection of the communication line.

[0097] In addition, in the present embodiment, an example has been shown in which the first cooling chamber 10 and the second cooling chamber 20 are disposed adjacent to each other, but the present invention is not limited to this. In the present invention, the first cooling chamber 10 and the second cooling chamber 20 may be provided apart from each other.

[0098] In addition, in the present embodiment, an example of the cooling device 100 including the cooling circuit C1 with a simple configuration has been shown, but the present invention is not limited to this. In the present invention, for example, an accumulator, a strainer, an evaporator inlet temperature sensor, an evaporator outlet temperature sensor, and a defrost sensor may be included in the configuration of the cooling circuit C1.

[0099] In the present embodiment, an example has been shown in which one display unit 5 displays information such as error indications for each of the first control unit 3 and the second control unit 4 and the operating status of the common compressor 1, but the present invention is not limited to this. In the present invention, a plurality of display units 5 may be provided for each of the first control unit 3 and the second control unit 4, and configured to display information. Also, for example, the first control unit 3 and the second control unit 4 may be configured to communicate with a separately provided upper level control unit, transmit error information and the operating status of the common compressor 1 to the upper level control unit, and have the upper level control unit display the error information and the operating status of the common compressor 1 on the display unit 5 of a separately provided terminal or the like.

[0100] In addition, in the present embodiment, an example has been shown in which the second control unit 4 is configured to control the second expansion valve 21 to open when communication with the first control unit 3 becomes impossible, but the present invention is not limited to this. In the present invention, for example, the first control unit 3 may be configured to open the first expansion valve 11 when a communication abnormality occurs.

[0101] In the present embodiment, the second control unit 4 performs control to keep the second expansion valve 21 open for at least a predetermined standby time when communication with the first control unit 3 is no longer possible, but the present invention is not limited to this. In the present invention, the second control unit 4 may be configured to keep the second expansion valve 21 open without setting a time limit for the time until communication is restored.

[0102] Although the present embodiment has been described by way of example, the present invention is not limited to this.

[0103] In the present embodiment, the second control unit 4 controls the opening degree of the second expansion valve 21 when communication with the first control unit 3 is not possible when the cooling device 100 is powered on to be smaller than the opening degree of the second expansion valve 21 when communication with the first control unit 3 is not possible when the cooling device 100 is stopped, but the present invention is not limited to this. In the present invention, the second control unit 4 may be configured to control the opening degree of the second expansion valve 21 when communication with the first control unit 3 is not possible when the cooling device 100 is powered on to be the same as the opening degree of the second expansion valve 21 when communication with the first control unit 3 is not possible when the cooling device 100 is stopped.

[0104] In the present embodiment, when the second control unit 4 is unable to communicate with the first control unit 3 when the cooling device 100 is powered on, the second control unit 4 adjusts the second expansion valve 21 to an opening degree corresponding to the operation mode that was to be performed when communication with the first control unit 3 was possible, when a pressure equilibrium time for bringing the pressures of the first cooling chamber 10 and the second cooling chamber 20 closer to a balanced state has elapsed or when communication with the first control unit 3 is restored, but the present invention is not limited to this. In the present invention, the second expansion valve 21 may be configured to adjust the opening degree corresponding to the operation mode that was to be performed when communication with the first control unit 3 was possible only when communication with the first control unit 3 is restored.

[0105] In the present embodiment, when the second control unit 4 is unable to communicate with the first control unit 3 while the cooling device 100 is stopped, the second expansion valve 21 is controlled to be fully open for a pressure equilibrium time for bringing the pressures in the first cooling chamber 10 and the second cooling chamber 20 closer to a balanced state, but the present invention is not limited to this. In the present invention, the second expansion valve 21 may be fully opened without setting a period, or the second expansion valve 21 may be configured to open at an opening degree other than fully open.

[0106] In the present embodiment, when the second control unit 4 is unable to communicate with the first control unit 3 while cooling is stopped in the cooling device 100, the second control unit 4 performs control to fully close the second expansion valve 21 even if the state in which communication with the first control unit 3 is not possible continues after the pressure equilibrium time has elapsed, but the present invention is not limited to this. In the present invention, the second expansion valve 21 may be configured not to be fully closed if the state in which communication with the first control unit 3 is not possible continues even after the pressure equilibrium time has elapsed.

[0107] In the present embodiment, when the second control unit 4 is unable to communicate with the first control unit 3 while the cooling device 100 is stopped, and after the pressure equilibrium time has elapsed, the second control unit 4 acquires from the first control unit 3 control information indicating that temperature control using the first expansion valve 11 is not being performed and control information indicating that the common compressor 1 is operating, and controls the second expansion valve 21 to open at a smaller degree than the fully open state, but the present invention is not limited to this. In the present invention, the second control unit 4 may be configured to continue the control of keeping the second expansion valve 21 in the fully open state for a desired period of time.

[0108] In addition, in the present embodiment, an example is shown in which the waiting time is 120 seconds and the pressure equilibration time is 600 seconds, but the present invention is not limited to this. In the present invention, these times may be set arbitrarily. [Explanation of symbols]

[0109] 1 Common compressor 2 Condenser 3. First Control Section 4. Second Control Section 5 Display section 6. Third Control Section 10 1st cooling room 11 First expansion valve 12 First evaporator 20 Second cooling room 21 Second expansion valve 22 Second evaporator 30 Third cooling room 31 Third expansion valve 32 Third evaporator 13, 23, 33 Cooling chamber temperature sensor 100, 200 cooling device 110, 210 Cooling system C1, C2 cooling circuit M product

Claims

1. a first evaporator provided in the first cooling chamber and configured to evaporate a refrigerant; a second evaporator provided in the second cooling chamber and configured to evaporate the refrigerant; a first expansion valve provided in the first evaporator to expand a refrigerant and adjust an amount of the refrigerant supplied to the first evaporator; a second expansion valve provided in the second evaporator to expand the refrigerant and adjust the amount of the refrigerant supplied to the second evaporator; a common compressor provided in common to the first evaporator and the second evaporator, the common compressor compressing a refrigerant; A first control unit that controls the common compressor and the first expansion valve; A second control unit that controls the second expansion valve. The first control unit acquires control information regarding whether or not temperature control using the second expansion valve is being performed from at least the second control unit through communication; A cooling device, wherein the first control unit is configured to perform control to operate the common compressor when the first control unit acquires the control information from the second control unit indicating that temperature control is being performed using the second expansion valve.

2. The cooling device according to claim 1, wherein the first control unit is configured to control the common compressor to operate when the first expansion valve is in a closed state and the first control unit acquires the control information from the second control unit indicating that temperature control is being performed using the second expansion valve.

3. The cooling device according to claim 2, wherein the first control unit is configured to control the common compressor to continue operation when the first expansion valve is in a closed state and continues to receive the control information from the second control unit indicating that temperature control is being performed using the second expansion valve, and to control the common compressor to start operation when the first control unit receives the control information from the second control unit indicating that temperature control is not being performed using the second expansion valve and then receives the control information from the second control unit indicating that temperature control is being performed using the second expansion valve.

4. Each of the first control unit and the second control unit is configured to output a control signal for performing control to adjust an opening degree of the first expansion valve or the second expansion valve, 2. The cooling device of claim 1, wherein the first control unit is configured to control the common compressor so that the temperature of the first cooling chamber approaches the temperature of the second cooling chamber based on a priority indoor temperature, which is the higher indoor temperature of the first cooling chamber in which the first evaporator corresponding to the first expansion valve to which the control signal indicating an open state is input is provided, or the second cooling chamber in which the second evaporator corresponding to the second expansion valve to which the control signal indicating an open state is input is provided.

5. the first control unit is configured to output the control signal for adjusting an opening degree of the first expansion valve based on an indoor temperature of the first cooling chamber in which the first evaporator corresponding to the first expansion valve is provided when communication with the second control unit is not possible; The cooling device according to claim 4, wherein the second control unit is configured to output the control signal for adjusting the opening degree of the second expansion valve based on the indoor temperature of the second cooling chamber in which the second evaporator corresponding to the second expansion valve is provided when communication with the first control unit is not possible.

6. The cooling device according to claim 5 , wherein the first expansion valve and the second expansion valve have a structure that maintains an opening degree that was the same as when power was last supplied when power supply was stopped.

7. The cooling device according to claim 1 , wherein the second control unit is configured to perform control to open the second expansion valve when communication with the first control unit is not possible.

8. The cooling device according to claim 7, wherein the second control unit is configured to control the second expansion valve to continue to be open until at least a predetermined waiting time has elapsed when communication with the first control unit is not possible.

9. The cooling device according to claim 7, wherein the second control unit is configured to control the opening degree of the second expansion valve when communication with the first control unit is not possible when the cooling device is turned on to be smaller than the opening degree of the second expansion valve when communication with the first control unit is not possible when cooling of the cooling device is stopped.

10. The cooling device described in claim 9, wherein the second control unit is configured to control the second expansion valve to an opening degree corresponding to the operating mode that was scheduled to be implemented when communication with the first control unit is possible when communication with the first control unit is not possible when the cooling device is powered on, after a pressure equilibrium time has elapsed for bringing the pressures of the first cooling chamber and the second cooling chamber closer to a balanced state, or when communication with the first control unit is restored, to adjust the second expansion valve to an opening degree corresponding to the operating mode that was scheduled to be implemented when communication with the first control unit is possible.

11. The cooling device according to claim 9, wherein the second control unit is configured to control the second expansion valve to be fully open for a pressure equilibrium time for bringing the pressures in the first cooling chamber and the second cooling chamber closer to a balanced state when communication with the first control unit is not possible when cooling of the cooling device is stopped.

12. The cooling device according to claim 11, wherein the second control unit is configured to control the second expansion valve to be fully closed if communication with the first control unit is not possible when cooling of the cooling device is stopped, after the pressure equilibrium time has elapsed, even if the state in which communication with the first control unit is not possible continues.

13. The cooling device according to claim 11, wherein when communication with the first control unit is not possible when cooling of the cooling device is stopped and after the pressure equilibrium time has elapsed, the second control unit acquires from the first control unit the control information indicating that temperature control is not being performed using the first expansion valve and the control information indicating that the common compressor is operating, and then controls the second expansion valve to open at an opening smaller than a fully open state.

14. The first cooling chamber and the second cooling chamber are disposed adjacent to each other, The cooling device according to claim 1 , wherein the common compressor is disposed in a housing including the first cooling chamber and the second cooling chamber.

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