Control device, refrigeration cycle device provided with same, refrigeration cycle system provided with same, control method, and control program

Abstract

Provided are: a control device capable of ascertaining the flow rate of a fluid to be heat-exchanged while suppressing an increase in cost of the refrigeration cycle device; a refrigeration cycle device provided with the same, a refrigeration cycle system provided with the same; a control method; and a control program. A control device (5) of a refrigeration cycle device (2) comprises: a temperature acquisition unit (51) that acquires the temperature of a fluid to be heat-exchanged; a pressure acquisition unit (51) that acquires a plurality of pressures of the fluid to be heat-exchanged flowing through a heat exchanger (HE); a setting information acquisition unit (52) that acquires the type and concentration of the fluid to be heat-exchanged; a physical property value calculation unit (53) that calculates the density and the kinematic viscosity of the fluid to be heat-exchanged; and a flow rate calculation unit (54) that calculates the differential pressure of each pressure of the fluid to be heat-exchanged and calculates the flow rate of the fluid to be heat-exchanged by using the density, kinematic viscosity, and differential pressure of the fluid to be heat-exchanged with respect to a flow rate calculation formula that includes the density, kinematic viscosity, and differential pressure as parameters.

Description

Technical Field

[0001] The present disclosure relates to a control device, a refrigeration cycle device provided with the same, a refrigeration cycle system provided with the same, a control method, and a control program.Background Art

[0002] In the related art, in a refrigeration cycle device that supplies a heat-exchange fluid (for example, brine) cooled to a desired temperature, in order to measure a flow rate of the heat-exchange fluid, the flow rate of the heat-exchange fluid is directly measured using a flowmeter or the like. In addition, in such a refrigeration cycle device, an abnormality or the like in the flow rate of the heat-exchange fluid generated by freezing or the like has been detected by using the flow rate of the heat-exchange fluid directly measured.

[0003] PTL 1 discloses a method in which, in order to reduce costs, a pressure and a temperature of a refrigerant and a temperature of a heat-exchange fluid of a refrigeration cycle device are respectively detected instead of using a flowmeter in the refrigeration cycle device, and a flow rate of the heat-exchange fluid is calculated based on a detection result.

[0004] In addition, PTL 2 discloses that an absolute amount of a flow rate of a fluid to be cooled is calculated based on a low pressure of a refrigerant suctioned by a compressor included in a refrigeration cycle device, a temperature of the refrigerant suctioned by the compressor, an operating frequency of the compressor, a temperature of a refrigerant to be cooled flowing into an evaporator, and a temperature of the refrigerant to be cooled flowing out of the evaporator. In this way, PTL 2 discloses a technique of using a physical quantity related to an operation of the compressor when calculating the flow rate of the fluid to be cooled in the refrigeration cycle device.Citation ListPatent Literature

[0005] [PTL 1] Japanese Patent No. 5289475 [PTL 2] Japanese Patent No. 5058324 Summary of InventionTechnical Problem

[0006] However, for a method of using a pressure sensor instead of the flowmeter, the method can be applied only in a case where a specific heat-exchange fluid set by a user is used at the time of starting an operation of the refrigeration cycle device, and it cannot be applied in a case where various heat-exchange fluids are used by the user. Therefore, a settable range of the heat-exchange fluid to be used was limited. Therefore, in a case where the flow rate of the heat-exchange fluid is measured using the pressure sensor, it is required to expand the settable range of the heat-exchange fluid to be used.

[0007] In addition, in the method of the related art, a pressure or the temperature of the refrigerant suctioned by the compressor is used to calculate the flow rate of the heat-exchange fluid. That is, in the method of the related art, when only a fluid circuit on a heat-exchange fluid side operates, for example, in a case where only a pump operation is performed without a refrigerant operation on a refrigerating cycle side, the flow rate of the heat-exchange fluid cannot be calculated, and in order to calculate the flow rate of the heat-exchange fluid, it is necessary to operate a refrigerating cycle on a refrigerant side on which the compressor is provided. Therefore, there is room for improvement in efficiency in an operation of the refrigeration cycle device.

[0008] The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a control device capable of ascertaining a flow rate of a heat-exchange fluid while suppressing an increase in cost of a refrigeration cycle device, the refrigeration cycle device provided with the same, a refrigeration cycle system provided with the same, a control method, and a control program.Solution to Problem

[0009] A control device according to some embodiments of the present disclosure is a control device for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control device including: a temperature acquisition unit that acquires a temperature of the heat-exchange fluid; a pressure acquisition unit that acquires a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition unit that acquires setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation unit that calculates a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired by the temperature acquisition unit and the setting information acquired by the setting information acquisition unit; and a flow rate calculation unit that calculates a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

[0010] A refrigeration cycle device according to some embodiments of the present disclosure includes the control device.

[0011] A refrigeration cycle system according to some embodiments of the present disclosure includes the refrigeration cycle device, and a fluid circuit in which the heat-exchange fluid circulates.

[0012] A control method according to some embodiments of the present disclosure is a control method for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control method including: a temperature acquisition step of acquiring a temperature of the heat-exchange fluid; a pressure acquisition step of acquiring a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition step of acquiring setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation step of calculating a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired in the temperature acquisition step and the setting information acquired in the setting information acquisition step; and a flow rate calculation step of calculating a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated in the physical property value calculation step, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

[0013] A control program according to some embodiments of the present disclosure is a control program for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control program causing a computer to execute: a temperature acquisition process of acquiring a temperature of the heat-exchange fluid; a pressure acquisition process of acquiring a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition process of acquiring setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation process of calculating a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired in the temperature acquisition process and the setting information acquired in the setting information acquisition process; and a flow rate calculation process of calculating a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated in the physical property value calculation process, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.Advantageous Effects of Invention

[0014] According to the present disclosure, an effect is achieved in that the flow rate of the heat-exchange fluid can be ascertained at a low cost without being limited by the type or the concentration of the heat-exchange fluid.Brief Description of Drawings

[0015] FIG. 1 is a diagram schematically showing a configuration of a refrigeration cycle device according to one embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram showing an example of a hardware configuration of a control device of a refrigeration cycle device of FIG. 1. FIG. 3 is a flowchart showing an example of a procedure of a flow rate calculation process of a heat-exchange fluid in the refrigeration cycle device according to the embodiment of the present disclosure. FIG. 4 is a graph showing actual measurement results of a flow rate-pressure loss characteristic in the heat-exchange fluid. FIG. 5 is an example of a data sheet of a heat-exchange fluid manufacturer. FIG. 6 is a graph showing an approximation equation of a temperature and a density of the heat-exchange fluid. FIG. 7 is a graph showing an approximation equation of the temperature and a viscosity of the heat-exchange fluid. FIG. 8 is a dimensionless characteristic graph showing a relationship between a Reynolds number and a pressure loss / dynamic pressure of heat-exchange flow. FIG. 9 is a diagram schematically showing the configuration of the refrigeration cycle device according to the embodiment of the present disclosure. FIG. 10 is a graph showing specific gravity with respect to a concentration of the heat-exchange fluid. FIG. 11 is a graph showing a freezing temperature with respect to the concentration of the heat-exchange fluid. Description of Embodiments

[0016] Hereinafter, an embodiment of a control device, a refrigeration cycle device provided with the same, a refrigeration cycle system provided with the same, a control method, and a control program according to the present disclosure will be described with reference to the drawings.(Configuration of Refrigeration Cycle System)

[0017] FIG. 1 is a diagram schematically showing a configuration of a refrigeration cycle system 1 according to one embodiment of the present disclosure. As shown in FIG. 1, the refrigeration cycle system 1 includes a fluid circuit 4 and a refrigeration cycle device 2.(Fluid Circuit)

[0018] The fluid circuit 4 is a fluid circuit in which the heat-exchange fluid circulates, and as will be described later, the heat-exchange fluid that is heat-exchanged with a refrigerant circulating in a refrigerant circuit 3 in a heat exchanger HE and has a desired temperature is supplied to an equipment load 42. The fluid circuit 4 is provided with, for example, a pump 41, pressure sensors P1 and P2, and temperature sensors (temperature measurement units) T1 and T2. The heat-exchange fluid is, for example, a fluid such as water, and may be simply water or brine or the like obtained by mixing an additive that lowers the freezing point. Here, in the present embodiment, the heat-exchange fluid is brine, and for example, ethylene glycol, Nybrine Z1, Nybrine NFP, Showbrine Blue, Showbrine PFP, or the like may be used.

[0019] The pump 41 sends the heat-exchange fluid such that the heat-exchange fluid circulates in the fluid circuit 4. Here, the means for sending the heat-exchange fluid is not limited to a pump, and may be other types of sending means as long as the means serves the same role.

[0020] The pressure sensors P1 and P2 are provided, for example, at each of an inlet and an outlet of the heat exchanger HE in the fluid circuit 4. The pressure sensor P1 measures the pressure of the heat-exchange fluid flowing into the heat exchanger HE. In addition, the pressure sensor P2 measures the pressure of the heat-exchange fluid flowing out of the heat exchanger HE. Each measured pressure is transmitted to a control device 5 and is used for calculating the flow rate of the heat-exchange fluid to be described later. In addition, a differential pressure gauge that measures a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger HE and the pressure of the heat-exchange fluid flowing out of the heat exchanger HE may be used instead of the pressure sensors P1 and P2.

[0021] The temperature sensors T1 and T2 are provided, for example, at each of the inlet and outlet of the heat exchanger HE in the fluid circuit 4. The temperature sensor (first temperature measurement unit) T1 measures the temperature of the heat-exchange fluid flowing into the heat exchanger HE. In addition, the temperature sensor (second temperature measurement unit) T2 measures the temperature of the heat-exchange fluid flowing out of the heat exchanger HE. Each measured temperature is transmitted to a control device 5 and is used for calculating the flow rate of the heat-exchange fluid to be described later. In addition, in a case where the temperature difference between the inlet and the outlet of the heat exchanger HE is small, of the temperature sensors T1 and T2, only the temperature sensor T1 for measuring the temperature of the heat-exchange fluid flowing into the heat exchanger HE may be provided.(Refrigeration Cycle Device)

[0022] The refrigeration cycle device 2 includes the refrigerant circuit 3, the control device 5, a storage unit 6, and a notification unit 7. Detail of each configuration will be described below.(Refrigerant Circuit)

[0023] First, the refrigerant circuit 3 is a fluid circuit in which a refrigerant circulates, and includes a compressor 31, a heat exchanger 32, a pressure-reducing device 33, and the heat exchanger HE. For example, Hydrofluorocarbon (HFC) refrigerants such as R410A, R407C, and R404A, Hydrochlorofluorocarbon (HCFC) refrigerants such as R22 and R134a, or natural refrigerants such as hydrocarbons and helium can be used as the refrigerant circulating in the refrigerant circuit 3. The refrigerant circulating in the refrigerant circuit 3 is not limited thereto, and may be a refrigerant other than the above as long as it has the same refrigerant action.

[0024] The compressor 31 compresses the refrigerant circulating in the refrigerant circuit 3. In addition, the compressor 31 is a compressor whose operating capacity can be changed, and is composed of, for example, a positive-displacement compressor driven by a motor controlled by an inverter. The compressor 31 may have a configuration in which two or more compressors are connected in parallel or in series.

[0025] The heat exchanger 32 is specifically a condenser in which the refrigerant and the heat-exchange medium exchange heat with each other. The heat exchanger 32 is, for example, a fin-and-tube type heat exchanger configured to include a heat transfer tube and a large number of fins. The heat-exchange medium is, for example, a fluid such as air, and is supplied to the heat exchanger 32 by sending means such as a fan.

[0026] The pressure-reducing device 33 adjusts the flow rate of the refrigerant flowing through the refrigerant circuit 3, for example. As the pressure-reducing device 33, an electronic expansion valve capable of adjusting the opening degree of the orifice by a stepping motor (not shown), a mechanical expansion valve using a diaphragm in a pressure-sensing section, a capillary tube, or the like may be used.

[0027] The heat exchanger HE is a heat exchanger in which a refrigerant circulating in the refrigerant circuit 3 pressure-reduced by the pressure-reducing device 33 and the heat-exchange fluid circulating in the fluid circuit 4 exchange heat with each other. In addition, the heat exchanger HE is specifically an evaporator, and for example, a fin-and-tube type heat exchanger is used. In addition, the heat exchanger HE is a component of the refrigerant circuit 3 and is a component of the fluid circuit 4.(Control Device)

[0028] The control device 5 calculates the flow rate of the heat-exchange fluid based on each pressure measured by the pressure sensors P1 and P2, each temperature measured by the temperature sensors T1 and T2, and setting information on the type and concentration of the heat-exchange fluid that is input by a user, and performs drive control of the compressor 31 and the pressure-reducing device 33 which are included in the refrigerant circuit 3 and the pump 41 included in the fluid circuit 4. In addition, the control device 5 includes an operating state information acquisition unit 51, a setting information acquisition unit 52, a physical property value calculation unit 53, a flow rate calculation unit 54, a capacity calculation unit 55, an abnormality determination unit 56, an abnormality processing unit 57, a device drive control unit 58, and the storage unit 6.

[0029] Here, FIG. 2 is a schematic configuration diagram showing an example of a hardware configuration of the control device 5 of the refrigeration cycle device 2 of FIG. 1. As shown in FIG. 2, the control device 5 has a computer (computer system) and includes, for example, a CPU 5a, an auxiliary storage device (ROM) 5b for storing programs executed by the CPU 5a, data referenced by these programs, and the like, a main storage device (RAM) 5c that functions as a work area when each program is executed, a communication interface 5d for connecting to a network, an input / output unit 5e that receives inputs from external devices and outputs control commands to external devices that can communicate with the control device 5, and the like. Each of these units is connected via, for example, a bus 5f. As the auxiliary storage device 5b, for example, a magnetic disk, a magneto-optical disk, a semiconductor memory, or the like can be given as an example.

[0030] As an example, a series of processes for implementing various functions which will be described later are stored in the auxiliary storage device 5b in the form of a program, the CPU 5a reads the program into the main storage device 5c to execute an information processing and calculation process, and thus, various functions are implemented. As the program, a form installed in advance in the auxiliary storage device 5b, a form which is provided in a state of being stored in another computer-readable storage medium, a form which is distributed via wired or wireless communication means, or the like may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

[0031] FIG. 1 will be referred to again.

[0032] The operating state information acquisition unit (pressure acquisition unit, temperature acquisition unit) 51 acquires the pressure of the heat-exchange fluid by the pressure sensors P1 and P2, acquires the temperature of the heat-exchange fluid by the temperature sensors T1 and T2, and outputs the acquired pressure and temperature to each of the physical property value calculation unit 53 and the flow rate calculation unit 54.

[0033] In the following description, it is described that the operating state information acquisition unit 51 can acquire physical quantities such as the temperature of the refrigerant circulating in the refrigerant circuit 3 and the temperature, pressure, differential pressure, and the like of the heat-exchange fluid circulating in the fluid circuit 4. However, the present disclosure is not limited to this example, and the operating state information acquisition unit 51 may appropriately include a temperature acquisition unit that acquires at least one of the temperature of the refrigerant circulating in the refrigerant circuit 3 and the temperature of the heat-exchange fluid circulating in the fluid circuit 4, a pressure acquisition unit that acquires at least one of the pressure of the refrigerant circulating in the refrigerant circuit 3 and the pressure of the heat-exchange fluid circulating in the fluid circuit 4, and a differential pressure acquisition unit that acquires at least one of the differential pressure of the refrigerant circulating in the refrigerant circuit 3 and the differential pressure of the heat-exchange fluid circulating in the fluid circuit 4.

[0034] The setting information acquisition unit 52 acquires the setting information on the type and the concentration of the heat-exchange fluid. The setting information on the type and concentration of the heat-exchange fluid is set by the user, for example, via a user interface (not shown). Here, the setting information on the type and the concentration of the heat-exchange fluid that is set by the user is used for the calculation of the physical property value of the heat-exchange fluid. Therefore, the setting information acquisition unit 52 outputs the setting information on the type and the concentration of the heat-exchange fluid to the physical property value calculation unit 53.

[0035] The physical property value calculation unit 53 calculates the density and kinematic viscosity of the heat-exchange fluid by using the temperature of the heat-exchange fluid received from the operating state information acquisition unit 51 and the setting information on the type and concentration of the heat-exchange fluid received from the setting information acquisition unit 52. The physical property value calculation unit 53 outputs the calculated density and kinematic viscosity of the heat-exchange fluid to each of the flow rate calculation unit 54 and the capacity calculation unit 55.

[0036] In addition, the physical property value calculation unit 53 may use a data table and a calculation equation relating to the physical property values of the heat-exchange fluid, which are stored in the storage unit 6 (to be described later), in the calculation of the density and the kinematic viscosity of the heat-exchange fluid. In addition, the physical property value calculation unit 53 may calculate an average temperature in a case where there are a plurality of temperatures of the heat-exchange fluid received from the operating state information acquisition unit 51. The physical property values calculated by the physical property value calculation unit 53 are not limited to the above-described values, and other physical property values such as specific heat may be calculated.

[0037] The flow rate calculation unit 54 calculates a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates the flow rate of the heat-exchange fluid by using the density and kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit 53, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters. The flow rate calculation unit 54 outputs the calculated flow rate of the heat-exchange fluid to each of the capacity calculation unit 55 and the abnormality determination unit 56.

[0038] In addition, the flow rate calculation unit 54 may use a calculation equation for calculating the flow rate of the heat-exchange fluid stored in the storage unit 6 (to be described later) in calculating the flow rate of the refrigerant or the heat-exchange fluid.

[0039] Further, the flow rate calculation unit 54 may output the calculation result to the outside by monitoring display or the like in order to notify the user of the calculated flow rate of the heat-exchange fluid.

[0040] The capacity calculation unit 55 calculates the capacity of the refrigerant circuit 3, the capacity of the fluid circuit 4, and the capacity of the refrigeration cycle device 2 based on each calculation result of the physical property value calculation unit 53 and the flow rate calculation unit 54. For example, the capacity calculation unit 55 calculates the heat exchange amount between the refrigerant and the heat-exchange fluid. The capacity calculation unit 55 outputs the calculation result to the outside by monitoring display or the like in order to notify the user of the current capacity of the refrigeration cycle device 2 based on the calculation result.

[0041] The abnormality determination unit 56 determines presence or absence of an abnormality in the flow rate of the heat-exchange fluid, based on a calculation result of the flow rate calculation unit 54. In addition, the abnormality determination unit 56 outputs the determination result of the abnormality determination to the abnormality processing unit 57.

[0042] In addition, in a case where the abnormality determination unit 56 determines that there is an abnormality in the flow rate, the abnormality determination unit 56 transmits a signal indicating that there is an abnormality determination to the notification unit 7. The notification unit 7 notifies the user of the refrigeration cycle device 2 that an abnormality has occurred in the flow rate.

[0043] The abnormality determination unit 56 may be capable of determining an abnormality regarding other physical property values, such as the concentration or the like of the heat-exchange fluid, not only the flow rate of the heat-exchange fluid.

[0044] In a case where the abnormality processing unit 57 receives the determination result from the abnormality determination unit 56 that there is an abnormality in the flow rate, the abnormality processing unit 57 outputs a command to the device drive control unit 58 to cause each device included in the refrigerant circuit 3 or the fluid circuit 4 to perform a dedicated operation in a case where an abnormality occurs. The dedicated operation may be, for example, an operation set in advance, or may be a command for emergency stop.

[0045] The device drive control unit 58 uses the calculation result of the flow rate calculation unit 54 as one of the parameters to perform drive control on each device such as the compressor 31, the pressure-reducing device 33, and the pump 41. For example, the device drive control unit 58 controls the rotation speed of the compressor 31, the opening degree of the valve in a case where the pressure-reducing device 33 is the valve, the rotation speed of the pump 41, and the like, so that the pressure, the temperature, the flow rate, and the like of the refrigerant circulating in the refrigerant circuit 3 and of the heat-exchange fluid circulating in the fluid circuit 4 are controlled.

[0046] In addition, in a case where the device drive control unit 58 receives a command for performing an emergency stop at the time of an abnormality from the abnormality processing unit 57, the device drive control unit 58 may perform an emergency stop on each device included in the refrigerant circuit 3 and the fluid circuit 4 based on the command.(Storage Unit)

[0047] The storage unit 6 is configured by, for example, a memory device such as a semiconductor memory or a hard disk device. The storage unit 6 stores each calculation equation used when the physical property value calculation unit 53 calculates physical property values such as density and kinematic viscosity, and a flow rate calculation equation used when the flow rate calculation unit 54 calculates the flow rate of the heat-exchange fluid. In addition, the storage unit 6 stores a plurality of data tables for obtaining each physical property value in which the temperature and the differential pressure are associated with each other for each combination of the type and the concentration of the heat-exchange fluid. The data table stores, for example, a density table showing a relationship between the temperature, type, and concentration and the density of the heat-exchange fluid, a viscosity table showing a relationship between the temperature, type, and concentration and the viscosity of the heat-exchange fluid, a specific heat table showing a relationship between the temperature, type, and concentration and the specific heat of the heat-exchange fluid, a specific gravity table showing a relationship between the concentration and the specific gravity of the heat-exchange fluid, and a freezing temperature table showing a relationship between the concentration and the freezing temperature of the heat-exchange fluid.

[0048] Each calculation equation used by the physical property value calculation unit 53 and the flow rate calculation equation used by the flow rate calculation unit 54 are derived by using at least one type of the plurality of data tables. In addition, the storage unit 6 may store specifications such as dimensions of a pipe through which the heat-exchange fluid flows. The storage unit 6 may be capable of communicating with the control device 5, and each calculation unit included in the control device 5 may use each table stored in the storage unit 6 when performing calculation.

[0049] The storage unit 6 is configured by a memory device such as a semiconductor memory or a hard disk device, and is not limited to the configuration of the control device 5. The storage unit 6 may be provided to be accessible by the control device 5, and may be a cloud service, for example, an online storage or the like.(Notification Unit)

[0050] The notification unit 7 is a display screen such as a light emitting diode (LED) or a cathode ray tube (CRT), or a liquid crystal screen, and outputs information on the screen. In a case where the determination result is the flow rate abnormality, the display output of the flow rate abnormality is performed in accordance with an instruction from the abnormality determination unit 56. Further, the notification unit 7 may include a voice output unit such as a speaker, and may output information by voice such as an alarm instead of display output on the screen or together with display output on the screen. Further, the notification unit 7 may have a communication line and may execute communication data output to a remote place.(About Flow Rate Calculation)

[0051] Hereinafter, details of the contents of each calculation by the storage unit 6, the physical property value calculation unit 53, and the flow rate calculation unit 54 will be described.

[0052] First, the physical property value calculation unit 53 calculates a density ρ of the heat-exchange fluid by using the temperature of the heat-exchange fluid obtained via the operating state information acquisition unit 51 and the setting information on the type and concentration of the heat-exchange fluid received from the setting information acquisition unit 52 by the following Equation (1) stored in the storage unit 6. ρ = ∫ Tin Tout ρ t dt Tout − Tin

[0053] In Equation (1), ρ is the density of the heat-exchange fluid, Tin is the temperature of the heat-exchange fluid flowing into the heat exchanger HE, and Tout is the temperature of the heat-exchange fluid flowing out of the heat exchanger HE. Here, ρ(t) is an approximation equation relating to the density of the heat-exchange fluid based on the actually measured value actually measured in advance, and t is the temperature of the heat-exchange fluid. Details of the approximation equation ρ(t) will be described later.

[0054] In addition, the physical property value calculation unit 53 calculates a viscosity µ of the heat-exchange fluid by using the temperature of the heat-exchange fluid obtained via the operating state information acquisition unit 51 and the setting information on the type and concentration of the heat-exchange fluid received from the setting information acquisition unit 52 by the following Equation (2) stored in the storage unit 6. μ = ∫ Tin Tout μ t dt Tout − Tin

[0055] In Equation (2), µ is the viscosity of the heat-exchange fluid, Tin is the temperature of the heat-exchange fluid flowing into the heat exchanger HE, and Tout is the temperature of the heat-exchange fluid flowing out of the heat exchanger HE. Here, µ(t) is an approximation equation relating to the viscosity of the heat-exchange fluid based on the actually measured value actually measured in advance, and t is the temperature of the heat-exchange fluid. Details of the approximation equation µ(t) will be described later.

[0056] The physical property value calculation unit 53 further calculates a kinematic viscosity v of the heat-exchange fluid by using the density ρ and the viscosity µ obtained by Equation (1) and Equation (2) by the following Equation (3) stored in the storage unit 6. ν = μ / ρ

[0057] In this way, the physical property value calculation unit 53 calculates the density ρ, the viscosity µ, and the kinematic viscosity v, which are physical property values of the heat-exchange fluid, by using each calculation equation stored in the storage unit 6. In addition, the physical property value calculation unit 53 outputs the density ρ and the kinematic viscosity v to the flow rate calculation unit 54.

[0058] Next, the flow rate calculation unit 54 calculates a flow rate Q by using the density and kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit 53, and a differential pressure calculated by the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger by the following Equation (4) stored in the storage unit 6. Q = α Δ p ρν β γ

[0059] In Equation (4), Q is the flow rate of the heat-exchange fluid, Δp is the differential pressure, ρ is the density of the heat-exchange fluid, v is the kinematic viscosity of the heat-exchange fluid, and predetermined values α, β, and γ are predetermined values obtained in advance by actual measurement. Here, details of specific setting means for the predetermined values α, β, and γ will be described later.

[0060] From the above, the physical property value calculation unit 53 calculates the density and kinematic viscosity of the heat-exchange fluid by using the temperature measured by the temperature sensors T1 and T2 and the setting information (type and concentration of the heat-exchange fluid) acquired by the setting information acquisition unit 52. In addition, the flow rate calculation unit 54 calculates the flow rate of the heat-exchange fluid by using the density and kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit 53, and the differential pressure calculated by the pressure of the heat-exchange fluid flowing into the heat-exchanger HE and the pressure of the heat-exchange fluid flowing out of the heat exchanger HE with respect to the flow rate calculation equation that includes the density, kinematic viscosity, and differential pressure as parameters.

[0061] According to such a method, the flow rate of the heat-exchange fluid can be ascertained without providing the flowmeter, that is, while suppressing an increase in the cost of the refrigeration cycle device 2. The flow rate of the heat-exchange fluid can be accurately calculated without being limited by the type or the concentration of the heat-exchange fluid set arbitrarily by the user. Further, since the flow rate of the heat-exchange fluid can be ascertained based on the temperature, the differential pressure, the type, and the concentration of the heat-exchange fluid flowing through the fluid circuit 4, the flow rate of the heat-exchange fluid can be ascertained even in a state where the refrigerant circuit 3 on the refrigerant side is not driven.(Flow Rate Calculation in Refrigeration Cycle Device)

[0062] Next, an example of the flow rate calculation process of the heat-exchange fluid in the refrigeration cycle device 2 will be described. FIG. 3 is a flowchart showing an example of a procedure of a flow rate calculation process of a heat-exchange fluid in the refrigeration cycle device 2 according to the embodiment of the present disclosure.

[0063] First, as a preliminary preparation for performing the flow rate calculation process of the heat-exchange fluid, the predetermined values α, β, and γ are acquired by measurement on the actual device (S101). Next, the user sets the type and concentration of the heat-exchange fluid used in the refrigeration cycle device 2 (S102).

[0064] Next, the operating state information acquisition unit 51 acquires each pressure measured by the pressure sensors P1 and P2. Further, the operating state information acquisition unit 51 acquires each temperature measured by the temperature sensors T1 and T2 (S103).

[0065] Next, the flow rate calculation unit 54 calculates a differential pressure Δp between the pressure of the heat-exchange fluid flowing into the heat exchanger HE and the pressure of the heat-exchange fluid flowing out of the heat exchanger HE (S104). Next, the physical property value calculation unit 53 calculates the density ρ by the type and concentration of the heat-exchange fluid and an integral average of the inlet and outlet temperatures of the heat exchanger HE (S105).

[0066] Next, the physical property value calculation unit 53 calculates the viscosity µ by the type and concentration of the heat-exchange fluid and the integral average of the inlet temperature and outlet temperature of the heat exchanger HE (S106). Next, the physical property value calculation unit 53 calculates the kinematic viscosity v from the density ρ and the viscosity µ (S107).

[0067] Finally, the flow rate calculation unit 54 calculates the flow rate Q from the differential pressure Δp, the density ρ, and the kinematic viscosity v of the heat-exchange fluid and the predetermined values α, β, and γ (S108).

[0068] As described above, the flow rate of the heat exchange fluid is calculated by the flow rate calculation unit 54, so that the flow rate of the heat-exchange fluid can be ascertained without providing the flowmeter, that is, while suppressing an increase in the cost of the refrigeration cycle device 2. In addition, the flow rate of the heat-exchange fluid can be accurately calculated without being limited by the type or the concentration of the heat-exchange fluid set arbitrarily by the user. Further, since the flow rate of the heat-exchange fluid can be ascertained based on the temperature, the differential pressure, the type, and the concentration of the heat-exchange fluid flowing through the fluid circuit 4, the flow rate of the heat-exchange fluid can be ascertained even in a state where the refrigerant circuit 3 on the refrigerant side is not driven.

[0069] In addition, in the flow shown in FIG. 3, steps may be added within a scope not departing from the gist of the present disclosure.

[0070] In addition, for example, after step S108, a step of determining the presence or absence of an abnormality in the flow rate of the heat-exchange fluid by the abnormality determination unit 56 based on the calculation result of the flow rate calculation unit 54 may be added.

[0071] In addition, for example, after step S108, a step of performing feedback control on each device such as the compressor 31, the pressure-reducing device 33, and the pump 41 by the device drive control unit 58 based on the calculation result of the flow rate calculation unit 54 may be added.

[0072] In addition, each process of the flow shown in FIG. 3 may be repeatedly executed at predetermined intervals during the operation of the fluid circuit 4.(Procedure for Deriving Each Calculation Equation)

[0073] The inventors have derived a calculation equation for calculating the density, kinematic viscosity, and flow rate of the heat-exchange fluid using the acquisition information related to the heat-exchange fluid in order to calculate the flow rate of the heat-exchange fluid according to the above procedure. Hereinafter, a procedure for deriving each calculation equation will be described.[Step (1) Measurement on Actual Device]

[0074] First, the measurement on the actual device is performed experimentally in advance to ascertain the relationship between the flow rate of the heat-exchange fluid and each parameter. Specifically, the pump 41 of the fluid circuit 4 is operated in a state where the refrigerant is not operated, that is, the refrigerant circuit 3 is not operated, the flow rate of the heat-exchange fluid and the inlet temperature and the outlet temperature of the heat exchanger HE are measured, and the flow rate-pressure loss (differential pressure) characteristic of the heat-exchange fluid is acquired. FIG. 4 is a graph showing actual measurement results of a flow rate-pressure loss characteristic in the heat-exchange fluid. In FIG. 4, the horizontal axis represents the flow rate of the heat-exchange fluid, and the vertical axis represents the differential pressure of the heat-exchange fluid. In FIG. 4, each of solid line, broken line, and one-dot chain line graphs has the same type and concentration of the heat-exchange fluid, and only the temperature of the heat-exchange fluid is different.

[0075] According to FIG. 4, the difference in the flow rate between a case where the inlet temperature of the heat-exchange fluid is -15°C and a case where the inlet temperature of the heat-exchange fluid is 15°C is about 5 m 3< / h. The physical property values of the heat-exchange fluid may be referred to technical data such as a data sheet of the heat-exchange fluid manufacturer (for example, refer to FIG. 5).[Step (2) Derivation of Approximation Equation Relating to Physical Property Value of Heat-Exchange Fluid and Inlet and Outlet Temperatures of Heat Exchanger]

[0076] Next, using the technical data of the heat-exchange fluid manufacturer, an approximation equation is created for the density and viscosity of the heat-exchange fluid with the temperature of the heat-exchange fluid as a variable.

[0077] FIG. 6 is a graph showing an approximation equation of the density created using the temperature of the heat-exchange fluid and the technical data of the heat-exchange fluid manufacturer. In FIG. 6, the horizontal axis represents the temperature of the heat-exchange fluid, and the vertical axis represents the density of the heat-exchange fluid. In addition, FIG. 7 is a graph showing an approximation equation of the viscosity created using the temperature of the heat-exchange fluid and the technical data of the heat-exchange fluid manufacturer. In FIG. 7, the horizontal axis represents the temperature of the heat-exchange fluid, and the vertical axis represents the viscosity of the heat-exchange fluid.

[0078] As shown in FIG. 6, the change in density with respect to the temperature of the heat-exchange fluid is substantially linear. From this, it is possible to obtain sufficient prediction accuracy for the change in density with respect to the temperature of the heat-exchange fluid with a second-order approximation equation. Specifically, the density with respect to the temperature of the heat-exchange fluid is calculated by the following Equation (5). In Equation (5), ρ(t) is a function of the density of the heat-exchange fluid, ρ 0 is a constant calculated when the approximation equation is created, ρ 1 and ρ 2 are coefficients calculated when the approximation equation is created, and t is the temperature of the heat-exchange fluid. ρ t = ρ 0 + ρ 1 t + ρ 2 t 2

[0079] In addition, as shown in FIG. 7, the change in viscosity with respect to the temperature of the heat-exchange fluid is not substantially linear as in FIG. 6. From this, it is possible to express the change in viscosity with respect to the temperature of the heat-exchange fluid with a fifth-order approximation equation because the change amount with respect to the temperature is large. The density with respect to the temperature of the heat-exchange fluid is calculated by the following Equation (6). In Equation (6), µ(t) is a function of the density of the heat-exchange fluid, µ 0 is a constant calculated when the approximation equation is created, µ 1 , µ 2 , µ 3 , µ 4 , and µ 5 are coefficients calculated when the approximation equation is created, and t is the temperature of the heat-exchange fluid. μ t = μ 0 + μ 1 t + μ 2 t 2 + μ 3 t 3 + μ 4 t 4 + μ 5 t 5

[0080] Here, when the physical property value is actually calculated during the operation of the refrigerant in the refrigerant circuit 3, the temperature difference between the inlet temperature and the outlet temperature of the heat exchanger HE of the fluid circuit 4 is large, with a maximum difference of 10°C. Therefore, an average value of the inlet temperature and the outlet temperature of the heat exchanger HE is used. For example, a highly accurate integral average value is used as a method for calculating the average value. Accordingly, Equation (1) for calculating the density of the heat-exchange fluid is derived using Equation (5). In addition, similarly, Equation (2) for calculating the density of the heat-exchange fluid is derived using Equation (6).[Step (3) Acquisition of Dimensionless Characteristics]

[0081] The Reynolds number and the pressure loss / dynamic pressure are calculated based on the data acquired in the above-described step (1). Here, a Reynolds number Re is calculated by the following Equation (7). In addition, the pressure loss / dynamic pressure is calculated by the following Expression (8). In Equation (7) and Expression (8), d is an inner diameter of a pipe through which the heat-exchange fluid flows, U is mean flow velocity in the pipe through which the heat-exchange fluid flows, and v is the kinematic viscosity of the heat-exchange fluid as described in Equation (3). In addition, the mean flow velocity U in the pipe is calculated by U = 4Q / πd 2< in a case where the flow rate of the heat-exchange fluid is defined as Q. Re = Ud ν Δp 1 2 ρU 2

[0082] A dimensionless characteristic graph is created from the relationship between the calculated Reynolds number and pressure loss / dynamic pressure. FIG. 8 is a dimensionless characteristic graph showing a relationship between a Reynolds number and a pressure loss / dynamic pressure of heat-exchange flow. In FIG. 8, the horizontal axis represents the Reynolds number, and the vertical axis represents the pressure loss / dynamic pressure. In this way, by creating the dimensionless characteristic graph, it is possible to display each condition in which the temperatures of the heat-exchange fluids are different on the same scale. Further, based on the dimensionless characteristic graph, an approximation equation between the Reynolds number and the pressure loss / dynamic pressure is created by using the power approximation.[Step (4) Derivation of Flow Rate Calculation Equation (Equation (4)) of Heat-Exchange Fluid]

[0083] Next, the approximation equation between the Reynolds number and the pressure loss / dynamic pressure created in step (3) is represented by the following Equation (9). Δp 1 2 ρU 2 = aRe 2

[0084] When Equation (7) and the mean flow velocity U in the pipe are substituted into Equation (9) and the equation is rearranged, the following Equation (10) is obtained. a and n are constants derived from a power approximation equation of the Reynolds number and the pressure loss / dynamic pressure. Q = π 4 2 a 1 n + 2 d n + 4 n + 2 Δ p ρν − n 1 n + 2

[0085] From Equation (10), since a, d, and n are constants, Equation (10) can be rearranged into the above Equation (4) by organizing Equation (10) and substituting a predetermined value α = (π / 4)(2 / a) 1 / (n + 2)< d (n + 4 / n + 2)< , β = -n, and γ = 1 / (n + 2).

[0086] As a result of the above-described steps, each of the calculation equations for calculating the density and the viscosity used by the physical property value calculation unit 53 and the flow rate calculation equation used by the flow rate calculation unit 54 are derived.

[0087] In addition, the inventors have checked that the flow rate of the heat-exchange fluid close to the actually measured value can be calculated by using the above-described Equation (4).

[0088] From the above, in the refrigeration cycle device 2 of the present disclosure, the flow rate calculation unit 54 calculates the differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger HE and the pressure of the heat-exchange fluid flowing out of the heat exchanger HE, and calculates the flow rate of the heat-exchange fluid by using the density and kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit 53, and the differential pressure with respect to the flow rate calculation equation that includes the density, kinematic viscosity, and differential pressure as parameters. Accordingly, the flow rate of the heat-exchange fluid can be ascertained without providing the flowmeter, that is, while suppressing an increase in the cost of the refrigeration cycle device 2. Further, since the flow rate of the heat-exchange fluid can be ascertained based on the temperature, the differential pressure, the type, and the concentration of the heat-exchange fluid flowing through the fluid circuit 4, the flow rate of the heat-exchange fluid can be ascertained even in a state where the refrigerant circuit 3 on the refrigerant side is not driven.

[0089] In addition, the flow rate calculation equation is a calculation equation derived from an approximation equation representing a relationship between a Reynolds number and a pressure loss / dynamic pressure of the heat-exchange fluid, which is derived using a plurality of pieces of data in which a temperature and a differential pressure are associated for each combination of the type and the concentration of the heat-exchange fluid. That is, the flow rate of the heat-exchange fluid is calculated using a predetermined calculation equation that is non-dimensionalized. In this manner, the flow rate of the heat-exchange fluid can be accurately calculated without being limited by the type or the concentration of the heat-exchange fluid set arbitrarily by the user.

[0090] In addition, the flow rate calculation of the heat-exchange fluid according to the present disclosure can reduce the number of data points to be acquired at the time of performing the flow rate calculation. For example, in a case where a differential pressure gauge that measures a differential pressure between the inlet and the outlet of the heat exchanger HE is provided in the fluid circuit 4 instead of the pressure sensors P1 and P2, the number of pieces of acquired data at the time of the flow rate calculation needs only be two data points of the differential pressure measured by the differential pressure gauge and the inlet temperature of the heat exchanger HE. In addition, even in a case where the differential pressure gauge is not provided and each temperature of the inlet and outlet of the heat exchanger HE is measured, it is only necessary to acquire four data points of each pressure of the inlet and outlet of the heat exchanger HE and each temperature of the inlet and outlet of the heat exchanger HE. In this way, the flow rate calculation according to the present disclosure has a smaller number of data points than the method in the related art in which the pressure and the temperature on the refrigerant side, the rotation speed of the compressor 31 provided in the refrigerant circuit 3, and the like are acquired. Therefore, it is possible to suppress software resource requirements in the calculation process. In addition, since the number of data points is small, a program can be easily created, and the occurrence of a design error can be suppressed.

[0091] In addition, the flow rate calculation of the heat-exchange fluid according to the present disclosure can be performed as long as at least two data points are acquired. Here, for example, when each of the plurality of data acquisition units (for example, sensors) has the same failure occurrence probability n, the failure occurrence probability in a case where there are two data acquisition units is 1 - (1 - n) 2< . Similarly, the failure occurrence probability in a case where there are two data acquisition units is 1 - (1 - n) 6< . In this way, regardless of the numerical value of n, when the number of data acquisition units is small, the probability of insufficient data for performing the flow rate calculation can be reduced. That is, the smaller the number of the data acquisition units is, the lower the probability that the flow rate calculation becomes impossible can be reduced.(Other Embodiments: Detection of Concentration Change in Heat-Exchange Fluid)

[0092] Regarding the refrigeration cycle device 2 in the present disclosure, the flow rate calculation of the heat-exchange fluid has been described. However, a method for calculating the capacity of the refrigeration cycle device 2 and a concentration change in the heat-exchange fluid will be described below using the above-described configuration. FIG. 9 is a diagram schematically showing a configuration of a refrigeration cycle system 10 according to the present embodiment. In the configuration diagram of FIG. 1, the pressure sensors P1 and P2 and the temperature sensors T1 and T2 are provided only in the fluid circuit 4. However, in the present embodiment, as shown in FIG. 9, pressure sensors P3 and P4 and temperature sensors T3 and T4 are also provided in the refrigerant circuit 3 in the same manner as in the fluid circuit 4.

[0093] The pressure sensors P3 and P4 are provided, for example, at each of an inlet and an outlet of the compressor 31 in the refrigerant circuit 3. The pressure sensor P3 measures the pressure of the refrigerant flowing into the compressor. In addition, the pressure sensor P4 measures the pressure of the refrigerant flowing out of the compressor 31. The measured pressure is transmitted to the control device 5 and is used for calculating the heat exchange amount of the refrigerant circuit 3 to be described later.

[0094] The temperature sensors T3 and T4 are provided, for example, at each of the inlet and outlet of the heat exchanger HE in the refrigerant circuit 3. The temperature sensor T3 measures the temperature of the heat-exchange fluid flowing into the heat exchanger HE. In addition, the temperature sensor T4 measures the temperature of the heat-exchange fluid flowing out of the heat exchanger HE. Each measured temperature is transmitted to the control device 5 and is used for calculating the heat exchange amount of the refrigerant circuit 3 to be described later.

[0095] In addition, the control device 5 in the present embodiment calculates enthalpy at each of the inlet and outlet of the heat exchanger HE using the operating state information received from the operating state information acquisition unit 51, specifically, the pressure of the refrigerant measured by the pressure sensor P3 and the temperatures of the refrigerant measured by the temperature sensors T3 and T4, and further calculates an enthalpy difference between the inlet and outlet of the heat exchanger HE. Regarding the pressure used for calculating the enthalpy difference between the inlet and outlet of the heat exchanger HE, a value obtained by considering the pressure loss generated by the heat exchanger HE may be used for the measurement result measured by the pressure sensor P3. In addition, in the present disclosure, an example in which each enthalpy is calculated by using the pressure measured by the pressure sensor P3 provided on the inlet side of the compressor 31 has been described. However, the present disclosure is not limited to this example, and more preferably, each enthalpy may be calculated by using the pressure measured by the pressure sensor provided on the inlet side of the heat exchanger HE.

[0096] Regarding the calculation of the enthalpy difference between the inlet and outlet of the heat exchanger HE, a known method may be appropriately adopted, and detailed description thereof will be omitted.

[0097] In addition, the abnormality determination unit 56 in the present embodiment is capable of bidirectional communication with the capacity calculation unit 55, and has a function of detecting the concentration change in the heat-exchange fluid by using the calculation result of the capacity calculation unit 55. In addition, the flow rate calculation unit 54 in the present embodiment can calculate the flow rate of the refrigerant circulating in the refrigerant circuit 3, and the capacity calculation unit 55 can calculate the capacity of the refrigerant circuit 3. Other configurations are the same as the configuration shown in FIG. 1.

[0098] First, in a case where the heat exchange between the refrigerant and the heat-exchange fluid is performed via the heat exchanger HE, the heat exchange amount in the heat exchanger HE changes according to the operating state of the refrigeration cycle device 2. The heat exchange amount of the refrigerant in the heat exchanger HE and the heat exchange amount of the heat-exchange fluid in the heat exchanger HE are equal to each other when the concentration of the heat-exchange fluid is normal. From this, in a case where the heat exchange amount in the refrigerant circuit 3 and the heat exchange amount in the fluid circuit 4 are not equal to each other, it is possible to consider that the concentration of the heat-exchange fluid has changed.

[0099] In order to check the concentration change in the heat-exchange fluid, first, the capacity calculation unit 55 calculates a first heat exchange amount Qr in the refrigerant circuit 3 and a second heat exchange amount Qb in the fluid circuit 4 by using each calculation result of a state value calculation unit 60, which will be described later, the physical property value calculation unit 53, and the flow rate calculation unit 54. The abnormality determination unit 56 detects the occurrence of the concentration change in the heat-exchange fluid based on the difference in heat exchange amount between the first heat exchange amount and the second heat exchange amount by comparing the calculated heat exchange amounts. In this way, the abnormality determination unit 56 functions as a concentration change detection unit that detects a change in the concentration of the heat-exchange fluid in the present embodiment. Not limited to this example, the control device 5 may include a concentration change detection unit independent of the abnormality determination unit 56.

[0100] Hereinafter, a method for calculating the first heat exchange amount Qr, which is a heat exchange amount in the refrigerant circuit 3, will be described.

[0101] First, the state value calculation unit 60 calculates an enthalpy difference between the inlet and outlet of the heat exchanger HE by using the operating state information (pressure and temperature) acquired by the operating state information acquisition unit 51. In addition, the flow rate calculation unit 54 calculates the flow rate of the refrigerant by using the displacement and the rotation speed of the compressor 31 which are acquired by the operating state information acquisition unit 51 and the density of the refrigerant calculated by the physical property value calculation unit 53. Regarding the derivation of the enthalpy difference between the inlet and outlet of the heat exchanger HE, the storage unit 6 may store a p-h line diagram of the refrigerant circulating in the refrigerant circuit 3, and the p-h line diagram may be used.

[0102] Next, the capacity calculation unit 55 calculates the first heat exchange amount Qr by using each calculation result of the state value calculation unit 60 and the flow rate calculation unit 54 by the following Equation (11). In Equation (11), Gr is the flow rate of the refrigerant calculated by the flow rate calculation unit 54. In addition, Δh is an enthalpy difference between the inlet and outlet of the heat exchanger HE calculated by the state value calculation unit 60. Qr = Gr × Δ h

[0103] Next, a method for calculating the second heat exchange amount Qb, which is a heat exchange amount in the fluid circuit 4, will be described.

[0104] First, the physical property value calculation unit 53 calculates the density, specific heat, and kinematic viscosity of the heat-exchange fluid and temperature difference of the heat-exchange fluid between the inlet and outlet of the heat exchanger HE using the operating state information (pressure and temperature) acquired by the operating state information acquisition unit 51 and the setting information (type and concentration) of the heat-exchange fluid acquired by the setting information acquisition unit 52. In addition, the flow rate calculation unit 54 calculates the flow rate of the heat-exchange fluid by using each physical property value calculated by the physical property value calculation unit 53 and the differential pressure in the inlet and outlet of the heat exchanger HE acquired by the operating state information acquisition unit 51.

[0105] Here, regarding the calculation of the flow rate of the heat-exchange fluid in the detection of the concentration change in the heat-exchange fluid, the calculation may be performed using the approximation equation derived by using the physical property value of the heat-exchange fluid calculated using the setting information (type and concentration) and the temperature of the heat-exchange fluid. As a differential pressure between the inlet and outlet of the heat exchanger HE of the fluid circuit 4, a value measured by using a differential pressure gauge may be used.

[0106] Next, the capacity calculation unit 55 calculates the first heat exchange amount Qr by using each calculation result of the physical property value calculation unit 53 and the flow rate calculation unit 54 by the following Equation (12). In Equation (12), Gb is the flow rate of the heat-exchange fluid calculated by the flow rate calculation unit 54. In addition, ρ is the density of the heat-exchange fluid calculated by the physical property value calculation unit 53, V is the flow rate of the heat-exchange fluid calculated by the flow rate calculation unit 54, c is the specific heat of the heat-exchange fluid calculated by the physical property value calculation unit 53, and ΔT is the temperature difference of the heat-exchange fluid between the inlet and outlet of the heat exchanger HE calculated by the physical property value calculation unit 53. Qb = ρ × Q × c × Δ T

[0107] Here, in a case where the abnormality determination unit 56 detects that a difference has occurred between the first heat exchange amount Qr and the second heat exchange amount Qb, this indicates that the concentration of the heat-exchange fluid has changed from the beginning of the operation, causing the density ρ, the flow rate V, and the specific heat c of the heat-exchange fluid to change in the fluid circuit 4. That is, it is possible to detect the occurrence of the concentration change in the heat-exchange fluid from the difference between the first heat exchange amount Qr and the second heat exchange amount Qb.

[0108] In a case where the abnormality determination unit 56 detects that the concentration of the heat-exchange fluid has changed, for example, in a case where the difference in heat exchange amount between the first heat exchange amount Qr and the second heat exchange amount Qb is equal to or greater than a predetermined value, the device drive control unit 58 may stop the operation of each device included in the refrigeration cycle device 2.

[0109] In a case where the abnormality determination unit 56 detects the concentration change in the heat-exchange fluid, in addition to stopping the operation of each device included in the refrigeration cycle device 2, the concentration change may be calculated, the correction amount for at least one of the setting information and the freezing temperature of the heat-exchange fluid may be calculated, and the user may be notified.

[0110] In a case where a difference occurs between the first heat exchange amount Qr and the second heat exchange amount Qb, that is, in a case where a difference occurs between the second heat exchange amount Qb at the beginning of the operation of the refrigeration cycle device 2 and the current second heat exchange amount Qb, the second heat exchange amount Qb changes since each of the density ρ, the flow rate V, and the specific heat c in the Equation (12) changes. Therefore, the concentration of the heat-exchange fluid can be calculated by using the change amounts of the density ρ, the flow rate V, and the specific heat c of the refrigeration cycle device 2 from the beginning of the operation to the present.

[0111] Here, FIG. 10 is a graph showing characteristics of specific gravity corresponding to the type and concentration of the heat-exchange fluid. In FIG. 10, the horizontal axis represents the concentration of the heat-exchange fluid, and the vertical axis represents the specific gravity of the heat-exchange fluid. Here, the specific gravity is a ratio between the density of the heat-exchange fluid and the density of a standard substance (for example, water). Therefore, there is a correlation between density and specific gravity, and the specific gravity changes as the density changes. That is, the capacity calculation unit 55 can calculate a change in specific gravity corresponding to a change in density, and can calculate a changed concentration from the specific gravity of the heat-exchange fluid after the change by using the relationship shown in FIG. 10. Further, the freezing temperature of the heat-exchange fluid can be derived from the concentration of the heat-exchange fluid as shown in FIG. 11. Therefore, the capacity calculation unit 55 can calculate not only the concentration change in the heat-exchange fluid but also a change in freezing temperature of the heat-exchange fluid by calculating the difference between the first heat exchange amount Qr and the second heat exchange amount Qb.

[0112] In this way, the capacity calculation unit 55 can calculate the concentration and the freezing temperature of the heat-exchange fluid changed from the beginning of the operation of the refrigeration cycle device 2, and thus can calculate the correction amount for at least one of the setting information and the freezing temperature of the heat-exchange fluid. In addition, the correction amount calculated by the capacity calculation unit 55 may be notified to the user by the notification unit 7.

[0113] The capacity calculation unit 55 can calculate the correction amount of the concentration of the heat-exchange fluid to make the capacity of the refrigeration cycle device 2 to be the same as that at the beginning of the operation even in a case where the concentration change in the heat-exchange fluid occurs, for example, in a case where the concentration changes due to evaporation or moisture absorption. In addition, since the calculation result is notified to the user by the notification unit 7, the user can identify the concentration change in the heat-exchange fluid and can correct the concentration of the heat-exchange fluid in order to deliver a predetermined capacity to the refrigeration cycle device 2.

[0114] In addition, even when the concentration of the heat-exchange fluid changes due to evaporation or moisture absorption of the heat-exchange fluid after the introduction of the facility, it is possible to notify of an abnormality and suppress the operation of the refrigeration cycle device 2 from being continued in a state where there is an abnormality in the physical property value of the heat-exchange fluid, and it is possible to suppress the occurrence of a failure or an accident. In addition, it is possible to eliminate the need to check the concentration of the heat-exchange fluid by regularly performing the maintenance.

[0115] In the above example, the concentration and the freezing temperature of the heat-exchange fluid are calculated by the capacity calculation unit 55. However, instead of this, a data table showing the relationship between the concentration and the freezing temperature of the heat-exchange fluid and a data table showing the relationship between the concentration and the freezing temperature of the heat-exchange fluid may be stored in the storage unit 6. In this case, the capacity calculation unit 55 may determine the correction amounts of the concentration and the freezing temperature of the heat-exchange fluid by referring to each data table.(Additional Remarks)

[0116] The present disclosure has been described above with reference to the embodiments, but the technical scope of the present disclosure is not limited to the above-described embodiments. Various modifications or improvements can be added to the above-described embodiments within the scope not departing from the concept of the present disclosure, and forms to which the modifications or the improvements are added are also included in the technical scope of the present disclosure. Further, the above embodiment may be appropriately combined.

[0117] The control device, the refrigeration cycle device provided with the same, the refrigeration cycle system provided with the same, the control method, and the control program described in the above-described embodiment are understood as follows, for example.

[0118] A control device (5) according to a first aspect of the present disclosure is a control device for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control device including: a temperature acquisition unit (51) that acquires a temperature of the heat-exchange fluid; a pressure acquisition unit (51) that acquires a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition unit (52) that acquires setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation unit (53) that calculates a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired by the temperature acquisition unit and the setting information acquired by the setting information acquisition unit; and a flow rate calculation unit (54) that calculates a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

[0119] According to the control device of the present disclosure, the temperature acquisition unit and the pressure acquisition unit acquire the temperature and the differential pressure of the heat-exchange fluid, and acquire the setting information on the type and the concentration of the heat-exchange fluid. The physical property value calculation unit calculates the density and kinematic viscosity of the heat-exchange fluid by using the temperature acquired by the temperature acquisition unit, the pressure acquired by the pressure acquisition unit, and the setting information acquired by the setting information acquisition unit. Further, the flow rate calculation unit calculates the differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates the flow rate of the heat-exchange fluid by using the density and kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit, and the differential pressure with respect to the flow rate calculation equation that includes the density, kinematic viscosity, and differential pressure as parameters. Accordingly, the flow rate of the heat-exchange fluid can be ascertained without providing the flowmeter, that is, while suppressing an increase in the cost of the refrigeration cycle device. Further, since the flow rate of the heat-exchange fluid can be ascertained based on the temperature, the differential pressure, the type, and the concentration of the heat-exchange fluid, the flow rate of the heat-exchange fluid can be ascertained even in a state where the refrigerant circuit on the refrigerant side is not driven.

[0120] In a control device according to a second aspect of the present disclosure, in the first aspect, the flow rate calculation equation is a calculation equation derived from an approximation equation representing a relationship between a Reynolds number and a pressure loss / dynamic pressure of the heat-exchange fluid, which is derived using a plurality of pieces of data in which a temperature and a differential pressure are associated for each combination of the type and the concentration of the heat-exchange fluid.

[0121] According to the control device of the present disclosure, the flow rate calculation equation is the calculation equation derived from the approximation equation representing the relationship between the Reynolds number and the pressure loss / dynamic pressure of the heat-exchange fluid, which is derived using the plurality of pieces of data in which the temperature and the differential pressure are associated for each combination of the type and the concentration of the heat-exchange fluid. That is, the flow rate of the heat-exchange fluid is calculated using a predetermined calculation equation that is non-dimensionalized. In this manner, the flow rate of the heat-exchange fluid can be accurately calculated without being limited by the type or the concentration of the heat-exchange fluid set arbitrarily by the user.

[0122] In a control device according to a third aspect of the present disclosure, in the first aspect or the second aspect, the temperature acquisition unit acquires a measurement result of a first temperature measurement unit (T1) that measures a first temperature of the heat-exchange fluid flowing into the heat exchanger and a measurement result of a second temperature measurement unit (T2) that measures a second temperature of the heat-exchange fluid flowing out of the heat exchanger, and the physical property value calculation unit calculates a temperature average of the first temperature and the second temperature.

[0123] According to the control device of the present disclosure, the temperature acquisition unit acquires the measurement result of the first temperature measurement unit that measures a temperature of the heat-exchange fluid flowing into the heat exchanger and the measurement result of the second temperature measurement unit that measures a temperature of the heat-exchange fluid flowing out of the heat exchanger, and the physical property value calculation unit calculates the temperature average of the first temperature and the second temperature. Accordingly, the temperature of the heat-exchange fluid can be more accurately acquired, and thus the flow rate of the heat-exchange fluid can be more accurately calculated.

[0124] A control device according to a fourth aspect of the present disclosure includes, in any one of the first aspect to the third aspect, a device drive control unit (58) that controls a compressor (31) compressing the refrigerant, a pressure-reducing device (33) reducing a pressure of the refrigerant, and a pump (41) sending the heat-exchange fluid, by using a calculation result of the flow rate calculation unit as one of the parameters.

[0125] According to the control device of the present disclosure, the device drive control unit that controls the compressor compressing the refrigerant, the pressure-reducing device reducing the pressure of the refrigerant, and the pump sending the heat-exchange fluid, based on the calculation result of the flow rate calculation unit. Accordingly, the state of the refrigerant flowing through the heat exchanger and the flow rate of the heat-exchange fluid can be appropriately controlled.

[0126] A control device according to a fifth aspect of the present disclosure includes, in any one of the first aspect to the fourth aspect, an abnormality determination unit (56) that determines presence or absence of an abnormality in the flow rate of the heat-exchange fluid, based on a calculation result of the flow rate calculation unit.

[0127] According to the control device of the present disclosure, the control device includes the abnormality determination unit that determines presence or absence of an abnormality in the flow rate of the heat-exchange fluid, based on the calculation result of the flow rate calculation unit. In this manner, it is possible to determine an abnormality in the flow rate of the heat-exchange fluid, and it is possible to suppress the operation from being continued in a state where there is an abnormality in the refrigeration cycle device.

[0128] A control device according to a sixth aspect of the present disclosure includes, in any one of the first aspect to the fifth aspect, a capacity calculation unit (55) that calculates a first heat exchange amount which is a heat exchange amount of the refrigerant in the heat exchanger and a second heat exchange amount which is a heat exchange amount of the heat-exchange fluid in the heat exchanger, and a concentration change detection unit (57) that detects a concentration change in the heat-exchange fluid, based on a difference in heat exchange amount between the first heat exchange amount and the second heat exchange amount.

[0129] According to the control device of the present disclosure, the capacity calculation unit calculates the first heat exchange amount which is the heat exchange amount of the refrigerant in the heat exchanger and the second heat exchange amount which is the heat exchange amount of the heat-exchange fluid in the heat exchanger, and the concentration change detection unit detects the concentration change in the heat-exchange fluid, based on a difference between the first heat exchange amount and the second heat exchange amount. In this manner, it is possible to suppress the operation of the refrigeration cycle device from being continued in a state where there is an abnormality in the physical property value of the heat-exchange fluid, and it is possible to suppress the occurrence of a failure or an accident. In addition, it is possible to eliminate the need to check the concentration of the heat-exchange fluid by regularly performing the maintenance.

[0130] A refrigeration cycle device according to a seventh aspect of the present disclosure includes the control device (5) according to any one of the first aspect to the sixth aspect.

[0131] A refrigeration cycle system according to an eighth aspect of the present disclosure includes the refrigeration cycle device (2) according to the seventh aspect, and a fluid circuit (4) in which the heat-exchange fluid circulates.

[0132] A control method according to a ninth aspect of the present disclosure is a control method for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger (HE), the control method comprising: a temperature acquisition step of acquiring a temperature of the heat-exchange fluid; a pressure acquisition step of acquiring a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition step of acquiring setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation step of calculating a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired in the temperature acquisition step and the setting information acquired in the setting information acquisition step; and a flow rate calculation step of calculating a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated in the physical property value calculation step, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

[0133] A control program according to a tenth aspect of the present disclosure is a control program for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger (HE), the control program causing a computer to execute: a temperature acquisition process of acquiring a temperature of the heat-exchange fluid; a pressure acquisition process of acquiring a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition process of acquiring setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation process of calculating a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired in the temperature acquisition process and the setting information acquired in the setting information acquisition process; and a flow rate calculation process of calculating a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated in the physical property value calculation process, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.Reference Signs List

[0134] 1: refrigeration cycle system 2: refrigeration cycle device 3: refrigerant circuit 4: fluid circuit 5: control device 5a: CPU 5b: auxiliary storage device (ROM) 5c: main storage device (RAM) 5d: communication interface 5e: input / output unit 5f: bus 6: storage unit 7: notification unit 10: refrigeration cycle system 31: compressor 32: heat exchanger 33: pressure-reducing device 41: pump 42: equipment load 51: operating state information acquisition unit 52: setting information acquisition unit 53: physical property value calculation unit 54: flow rate calculation unit 55: capacity calculation unit 56: abnormality determination unit 57: abnormality processing unit 58: device drive control unit 60: state value calculation unit HE: heat exchanger P1 to P4: pressure sensor T1 to T4: temperature sensor

Claims

1. A control device for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control device comprising: a temperature acquisition unit that acquires a temperature of the heat-exchange fluid; a pressure acquisition unit that acquires a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition unit that acquires setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation unit that calculates a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired by the temperature acquisition unit and the setting information acquired by the setting information acquisition unit; and a flow rate calculation unit that calculates a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated by the physical property value calculation unit, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

2. The control device according to Claim 1, wherein the flow rate calculation equation is a calculation equation derived from an approximation equation representing a relationship between a Reynolds number and a pressure loss / dynamic pressure of the heat-exchange fluid, which is derived using a plurality of pieces of data in which a temperature and a differential pressure are associated for each combination of the type and the concentration of the heat-exchange fluid.

3. The control device according to Claim 1, wherein the temperature acquisition unit acquires a measurement result of a first temperature measurement unit that measures a first temperature of the heat-exchange fluid flowing into the heat exchanger and a measurement result of a second temperature measurement unit that measures a second temperature of the heat-exchange fluid flowing out of the heat exchanger, and the physical property value calculation unit calculates a temperature average of the first temperature and the second temperature.

4. The control device according to Claim 1, further comprising: a device drive control unit that controls a compressor compressing the refrigerant, a pressure-reducing device reducing a pressure of the refrigerant, and a pump sending the heat-exchange fluid, by using a calculation result of the flow rate calculation unit as one of the parameters.

5. The control device according to Claim 1, further comprising: an abnormality determination unit that determines presence or absence of an abnormality in the flow rate of the heat-exchange fluid, based on a calculation result of the flow rate calculation unit.

6. The control device according to Claim 1, further comprising: a capacity calculation unit that calculates a first heat exchange amount which is a heat exchange amount of the refrigerant in the heat exchanger and a second heat exchange amount which is a heat exchange amount of the heat-exchange fluid in the heat exchanger; and a concentration change detection unit that detects a concentration change in the heat-exchange fluid, based on a difference in heat exchange amount between the first heat exchange amount and the second heat exchange amount.

7. A refrigeration cycle device comprising: the control device according to Claim 1.

8. A refrigeration cycle system comprising: the refrigeration cycle device according to Claim 7; and a fluid circuit in which the heat-exchange fluid circulates.

9. A control method for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control method comprising: a temperature acquisition step of acquiring a temperature of the heat-exchange fluid; a pressure acquisition step of acquiring a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition step of acquiring setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation step of calculating a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired in the temperature acquisition step and the setting information acquired in the setting information acquisition step; and a flow rate calculation step of calculating a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated in the physical property value calculation step, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

10. A control program for a refrigeration cycle device that supplies a heat-exchange fluid having a desired temperature by causing heat exchange between a refrigerant and the heat-exchange fluid in a heat exchanger, the control program causing a computer to execute: a temperature acquisition process of acquiring a temperature of the heat-exchange fluid; a pressure acquisition process of acquiring a pressure of the heat-exchange fluid flowing into the heat exchanger and a pressure of the heat-exchange fluid flowing out of the heat exchanger; a setting information acquisition process of acquiring setting information on a type and a concentration of the heat-exchange fluid; a physical property value calculation process of calculating a density and a kinematic viscosity of the heat-exchange fluid by using the temperature acquired in the temperature acquisition process and the setting information acquired in the setting information acquisition process; and a flow rate calculation process of calculating a differential pressure between the pressure of the heat-exchange fluid flowing into the heat exchanger and the pressure of the heat-exchange fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchange fluid by using the density and the kinematic viscosity of the heat-exchange fluid, which are calculated in the physical property value calculation process, and the differential pressure with respect to a flow rate calculation equation that includes the density, the kinematic viscosity, and the differential pressure as parameters.

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