Control device, refrigeration cycle device including the same, refrigeration cycle system including the same, control method and control program

Abstract

To provide a control device capable of grasping a flow rate of fluid to be subject to heat exchange while suppressing increase in cost of a refrigeration cycle device, the refrigeration cycle device including the control device, a refrigeration cycle system including the control device, a control method and a control program.SOLUTION: A control device 5 for a refrigeration cycle device 2 includes: a temperature acquisition section 51 that acquires a temperature of fluid to be subject to heat exchange; a pressure acquisition section 51 that acquires a plurality of pressures of the fluid to be subject to heat exchange flowing in a heat exchanger HE; a set information acquisition section 52 that acquires a type and concentration of the fluid to be subject to heat exchange; a physical property value calculation section 53 that calculates density and kinetic viscosity of the fluid to be subject to heat exchange; and a flow rate calculation section 54 that calculates a differential pressure between the respective pressures of the fluid to be subject to heat exchange and calculates a flow rate of the fluid to be subject to heat exchange by using the density and kinetic viscosity of the fluid to be subject to heat exchange and the differential pressure for a flow rate operational expression including density, kinetic viscosity and differential pressure as parameters.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a control device, a refrigeration cycle device including the control device, a refrigeration cycle system including the control device, a control method, and a control program. [Background technology]

[0002] Conventionally, in a conventional refrigeration cycle device that supplies a heat exchange fluid (e.g., brine) cooled to a desired temperature, in order to measure the flow rate of the heat exchange fluid, the flow rate of the heat exchange fluid is directly measured using a flow meter, etc. In addition, such a refrigeration cycle device detects an abnormality in the flow rate of the heat exchange fluid caused by freezing, etc., using the directly measured flow rate of the heat exchange fluid.

[0003] Patent document 1 discloses a method for reducing costs by not using a flow meter in a refrigeration cycle device, but instead detecting the pressure and temperature of the refrigerant in the refrigeration cycle device and the temperature of the heat exchange fluid, and calculating the flow rate of the heat exchange fluid based on the detection results.

[0004] Patent Document 2 also discloses that the absolute flow rate of the cooled fluid is calculated based on the low pressure of the refrigerant sucked into a compressor provided in the refrigeration cycle device, the temperature of the refrigerant sucked into the compressor, the operating frequency of the compressor, the temperature of the cooled refrigerant flowing into the evaporator, and the temperature of the cooled refrigerant flowing out of the evaporator. Thus, Patent Document 2 discloses a technology that uses physical quantities related to the operation of the compressor when calculating the flow rate of the cooled fluid in this refrigeration cycle device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5289475 [Patent Document 2] Patent No. 5058324 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the method of using a pressure gauge instead of a flow meter can only be applied when a specific heat exchange fluid set by the user at the start of operation of the refrigeration cycle device is used, and cannot be applied when various heat exchange fluids are used by users. Therefore, the settable range of the heat exchange fluid to be used is limited. Therefore, when measuring the flow rate of the heat exchange fluid using a pressure gauge, it is required to expand the settable range of the heat exchange fluid to be used.

[0007] In addition, in the conventional method, the pressure and temperature of the refrigerant sucked by the compressor are used to calculate the flow rate of the heat-exchanged fluid. In other words, in the conventional method, when only the fluid circuit on the heat-exchanged fluid side is operating, for example, when the refrigeration cycle side is not operating as a refrigerant but only pump operation is performed, the flow rate of the heat-exchanged fluid cannot be calculated, and in order to calculate the flow rate of the heat-exchanged fluid, it is necessary to operate the refrigeration cycle on the refrigerant side where the compressor is provided. Therefore, there is room for improving the efficiency of the operation of the refrigeration cycle device.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to provide a control device that can grasp the flow rate of the heat exchange fluid while suppressing an increase in the cost of the refrigeration cycle device, a refrigeration cycle device equipped with the same, a refrigeration cycle system equipped with the same, a control method, and a control program. [Means for solving the 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-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger, and includes a temperature acquisition unit that acquires the temperature of the heat-exchanged fluid, a pressure acquisition unit that acquires the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, a setting information acquisition unit that acquires setting information on the type and concentration of the heat-exchanged fluid, a physical property value calculation unit that calculates the density and kinetic viscosity of the heat-exchanged fluid 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 the differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and calculates the flow rate of the heat-exchanged fluid by using the density and kinetic viscosity of the heat-exchanged fluid and the differential pressure calculated by the physical property value calculation unit for a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters.

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

[0011] A refrigeration cycle system according to some embodiments of the present disclosure includes the above-described refrigeration cycle device and a fluid circuit through 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-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger, and includes a temperature acquisition process for acquiring the temperature of the heat-exchanged fluid; a pressure acquisition process for acquiring the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger; a setting information acquisition process for acquiring setting information on the type and concentration of the heat-exchanged fluid; a physical property calculation process for calculating the density and kinetic viscosity of the heat-exchanged fluid using the temperature acquired by the temperature acquisition process and the setting information acquired by the setting information acquisition process; and a flow rate calculation process for calculating the differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and calculating the flow rate of the heat-exchanged fluid by using the density, kinetic viscosity, and differential pressure of the heat-exchanged fluid calculated by the physical property calculation process for a flow rate calculation formula including density, kinetic viscosity, and 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-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger, the control program including a temperature acquisition process for acquiring a temperature of the heat-exchanged fluid, a pressure acquisition process for acquiring a pressure of the heat-exchanged fluid flowing into the heat exchanger and a pressure of the heat-exchanged fluid flowing out of the heat exchanger, a setting information acquisition process for acquiring setting information on the type and concentration of the heat-exchanged fluid, and a temperature acquisition process for acquiring information on the temperature acquired by the temperature acquisition process. The computer is caused to execute a physical property calculation process that calculates the density and kinetic viscosity of the heat exchange fluid using the setting information acquired by the setting information acquisition process, and a flow rate calculation process that 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, kinetic viscosity, and differential pressure of the heat exchange fluid calculated by the physical property calculation process for a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters. Effect of the Invention

[0014] According to the present disclosure, it is possible to grasp the flow rate of a heat exchange fluid at low cost, regardless of the type or concentration of the heat exchange fluid. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram illustrating a schematic configuration of a refrigeration cycle device according to an embodiment of the present disclosure. [Diagram 2] 2 is a schematic configuration diagram showing an example of a hardware configuration of a control device of the refrigeration cycle device of FIG. 1. [Diagram 3] 4 is a flowchart showing an example of a procedure for a flow rate calculation process of a heat exchange fluid in a refrigeration cycle apparatus according to an embodiment of the present disclosure. [Figure 4] 1 is a graph showing the results of measurements of flow rate-pressure loss characteristics in a heat exchange fluid. [Diagram 5] 1 is an example of a data sheet from a manufacturer of a heat exchange fluid. [Figure 6] 4 is a graph showing an approximation of the temperature and density of a heat exchange fluid. [Figure 7] 4 is a graph showing an approximation of the temperature and viscosity of a heat exchange fluid. [Figure 8] 1 is a dimensionless characteristic graph illustrating the relationship between the Reynolds number of a heat exchange flow and pressure loss / dynamic pressure. [Figure 9] 1 is a diagram illustrating a schematic configuration of a refrigeration cycle device according to an embodiment of the present disclosure. [Figure 10] 1 is a graph illustrating an example of specific gravity versus concentration of a heat exchange fluid. [Figure 11] 1 is a graph illustrating the freezing temperature versus the concentration of a heat exchange fluid. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of a control device, a refrigeration cycle device including the control device, a refrigeration cycle system including the control device, a control method, and a control program according to the present disclosure will be described with reference to the drawings.

[0017] (Configuration of refrigeration cycle system) 1 is a diagram illustrating a schematic configuration of a refrigeration cycle system 1 according to an embodiment of the present disclosure. As illustrated in FIG. 1, the refrigeration cycle system 1 includes a fluid circuit 4 and a refrigeration cycle device 2.

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

[0019] The pump 41 delivers the heat exchange fluid so that the heat exchange fluid circulates through the fluid circuit 4. Here, the means for delivering the heat exchange fluid is not limited to a pump, and other types of delivery means may be used as long as they perform a similar function.

[0020] The pressure sensors P1 and P2 are provided, for example, at the inlet and outlet, respectively, of the heat exchanger HE in the fluid circuit 4. The pressure sensor P1 measures the pressure of the heat-exchanged fluid flowing into the heat exchanger HE. The pressure sensor P2 measures the pressure of the heat-exchanged fluid flowing out from the heat exchanger HE. The measured pressures are transmitted to the control device 5 and used for calculating the flow rate of the heat-exchanged fluid, which will be described later. Instead of the pressure sensors P1 and P2, a differential pressure gauge may be used that measures the differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger HE and the pressure of the heat-exchanged fluid flowing out from the heat exchanger HE.

[0021] The temperature sensors T1, T2 are provided, for example, at the inlet and outlet, respectively, of the heat exchanger HE in the fluid circuit 4. The temperature sensor (first temperature measurement unit) T1 measures the temperature of the heat-exchanged fluid flowing into the heat exchanger HE. The temperature sensor (second temperature measurement unit) T2 measures the temperature of the heat-exchanged fluid flowing out from the heat exchanger HE. The measured temperatures are transmitted to the control device 5 and used for calculating the flow rate of the heat-exchanged fluid, which will be described later. Of the temperature sensors T1, T2, when the temperature difference between the inlet and outlet of the heat exchanger HE is small, only the temperature sensor T1 that measures the temperature of the heat-exchanged fluid flowing into the heat exchanger HE may be provided.

[0022] (Refrigeration cycle equipment) The refrigeration cycle device 2 includes a refrigerant circuit 3, a control device 5, a storage unit 6, and a notification unit 7. Each component will be described in detail below.

[0023] (Refrigerant circuit) First, the refrigerant circuit 3 is a fluid circuit through which a refrigerant circulates, and includes a compressor 31, a heat exchanger 32, a pressure reducer 33, and a heat exchanger HE. The refrigerant circulating through the refrigerant circuit 3 may be, for example, HFC refrigerants such as R410A, R407C, R404A, etc., HCFC refrigerants such as R22, R134a, etc., or natural refrigerants such as hydrocarbons and helium. Note that the refrigerant circulating through the refrigerant circuit 3 is not limited to these, and may be other refrigerants as long as they have a similar refrigerant effect.

[0024] The compressor 31 compresses the refrigerant circulating through the refrigerant circuit 3. The compressor 31 is a compressor whose operating capacity is variable, and is configured, for example, as a positive displacement compressor driven by a motor controlled by an inverter. The compressor 31 may be configured such that two or more compressors are connected in parallel or in series.

[0025] Specifically, the heat exchanger 32 is a condenser in which heat is exchanged between a refrigerant and a heat exchange medium. The heat exchanger 32 is, for example, a fin-and-tube type heat exchanger including a heat transfer tube and a number of fins. The heat exchange medium is, for example, a fluid such as air, and is supplied to the heat exchanger 32 by a delivery means such as a fan.

[0026] The pressure reducer 33 adjusts the flow rate of the refrigerant flowing through the refrigerant circuit 3. As the pressure reducer 33, an electronic expansion valve capable of adjusting the aperture by a stepping motor (not shown), a mechanical expansion valve employing a diaphragm in the pressure receiving portion, a capillary tube, or the like may be used.

[0027] The heat exchanger HE is a heat exchanger in which heat is exchanged between the refrigerant circulating in the refrigerant circuit 3 whose pressure has been reduced by the pressure reducer 33 and the heat-exchanged fluid circulating in the fluid circuit 4. Specifically, the heat exchanger HE is an evaporator, and a fin-and-tube heat exchanger, for example, is used. The heat exchanger HE is a component of the refrigerant circuit 3 and also a component of the fluid circuit 4.

[0028] (Control device) The control device 5 calculates the flow rate of the heat exchange fluid based on the pressures measured by the pressure sensors P1, P2, the temperatures measured by the temperature sensors T1, T2, and setting information on the type and concentration of the heat exchange fluid input by the user, and controls the drive of the compressor 31 and the pressure reducer 33 provided in the refrigerant circuit 3, and the pump 41 provided in the fluid circuit 4. The control device 5 also 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, an equipment drive control unit 58, and a memory unit 6.

[0029] Here, Fig. 2 is a schematic 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 and data referenced by the programs, 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 input from an external device and outputs a control command to an external device that can communicate with the control device 5, and the like. These units are connected, for example, via a bus 5f. Examples of the auxiliary storage device 5b include a magnetic disk, a magneto-optical disk, and a semiconductor memory.

[0030] A series of processes for realizing various functions described later is stored in the auxiliary storage device 5b in the form of a program, for example, and the CPU 5a reads this program into the main storage device 5c and executes information processing and arithmetic processing to realize various functions. The program may be pre-installed in the auxiliary storage device 5b, provided in a state stored in another computer-readable storage medium, or distributed via wired or wireless communication means. The computer-readable storage medium may be a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, etc.

[0031] Let us return to the explanation of Figure 1 again. The operating state information acquisition unit (pressure acquisition unit, temperature acquisition unit) 51 acquires the pressure of the heat exchange fluid using pressure sensors P1 and P2, and the temperature of the heat exchange fluid using temperature sensors T1 and T2, and outputs them to the physical property calculation unit 53 and the flow rate calculation unit 54, respectively. In the following explanation, the operating state information acquisition unit 51 is described as being capable of acquiring physical quantities such as the temperature of the refrigerant circulating through the refrigerant circuit 3 and the temperature, pressure, differential pressure, etc. of the heat-exchanged fluid circulating through the fluid circuit 4. However, this is not limited to the example, and the operating state information acquisition unit 51 may appropriately be equipped with a temperature acquisition unit that acquires the temperature of the refrigerant circulating through the refrigerant circuit 3 and at least one of the temperatures of the heat-exchanged fluid circulating through the fluid circuit 4, a pressure acquisition unit that acquires the temperature of the refrigerant circulating through the refrigerant circuit 3 and at least one of the pressures of the heat-exchanged fluid circulating through the fluid circuit 4, and a differential pressure acquisition unit that acquires the temperature of the refrigerant circulating through the refrigerant circuit 3 and at least one of the pressures of the heat-exchanged fluid circulating through the fluid circuit 4.

[0032] The setting information acquisition unit 52 acquires setting information on the type and concentration of the heat-exchanged fluid. The setting information on the type and concentration of the heat-exchanged fluid is set by a user, for example, via a user interface (not shown). Here, the setting information on the type and concentration of the heat-exchanged fluid set by the user is used to calculate the physical property values ​​of the heat-exchanged fluid. For this reason, the setting information acquisition unit 52 outputs the setting information on the type and concentration of the heat-exchanged fluid to the physical property value calculation unit 53.

[0033] The physical property value calculation unit 53 calculates the density and kinetic viscosity of the heat exchange fluid using the temperature of the heat exchange fluid received from the operating state information acquisition unit 51 and the setting information of the type and concentration of the heat exchange fluid received from the setting information acquisition unit 52. Then, the physical property value calculation unit 53 outputs the calculated density and kinetic viscosity of the heat exchange fluid to the flow rate calculation unit 54 and the capacity calculation unit 55, respectively.

[0034] Furthermore, in calculating the density and kinetic viscosity of the heat exchange fluid, the physical property value calculation unit 53 may use a data table and calculation formulas relating to the physical property values ​​of the heat exchange fluid stored in the storage unit 6 described below. Furthermore, when there are multiple temperatures of the heat exchange fluid received from the operating state information acquisition unit 51, the physical property value calculation unit 53 may calculate an average temperature. Note that the physical property values ​​calculated by the physical property value calculation unit 53 are not limited to those mentioned above, and other physical property values ​​such as specific heat may be calculated.

[0035] The flow rate calculation unit 54 calculates the differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and calculates the flow rate of the heat-exchanged fluid by using the density and kinetic viscosity of the heat-exchanged fluid and the differential pressure calculated by the physical property calculation unit 53 in a flow rate calculation formula including the density, kinetic viscosity, and differential pressure as parameters. The flow rate calculation unit 54 then outputs the calculated flow rate of the heat-exchanged fluid to each of the capacity calculation unit 55 and the abnormality determination unit 56.

[0036] Furthermore, the flow rate calculation unit 54 may use an arithmetic expression for calculating the flow rate of the heat exchange fluid stored in the storage unit 6 described below in calculating the flow rate of the heat exchange fluid. Furthermore, the flow rate calculation unit 54 may output the calculation result to the outside by displaying on a monitor or the like in order to inform the user of the calculated flow rate of the heat exchange fluid.

[0037] 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 apparatus 2 based on the calculation results of the physical property calculation unit 53 and the flow rate calculation unit 54. For example, the capacity calculation unit 55 calculates the heat exchange amount of the refrigerant and the heat exchange fluid. Then, based on the calculation result, the capacity calculation unit 55 outputs the calculation result to the outside by monitor display or the like to notify the user of the current capacity of the refrigeration cycle apparatus 2.

[0038] The abnormality determination unit 56 determines whether or not there is an abnormality in the flow rate of the heat exchange fluid based on the calculation result of the flow rate calculation unit 54. The abnormality determination unit 56 also outputs the result of the abnormality determination to the abnormality processing unit 57. Furthermore, when the abnormality determination unit 56 determines that there is an abnormality in the flow rate, it transmits a signal indicating that there is an abnormality to the notification unit 7. Then, the notification unit 7 notifies a user of the refrigeration cycle apparatus 2 that an abnormality has occurred in the flow rate. The abnormality determination unit 56 may perform abnormality determination not only with respect to the flow rate of the heat exchange fluid, but also with respect to other physical property values ​​such as the concentration of the heat exchange fluid.

[0039] When the abnormality processing unit 57 receives a determination result from the abnormality determination unit 56 that there is an abnormality in the flow rate, it outputs a command to the device drive control unit 58 to cause each device provided in the refrigerant circuit 3 or the fluid circuit 4 to perform a dedicated operation when an abnormality occurs. Note that the dedicated operation may be, for example, a preset operation, or may be a command for an emergency stop.

[0040] The equipment drive control unit 58 uses the calculation result of the flow rate calculation unit 54 as one of the parameters to control the drive of each of the equipment such as the compressor 31, the pressure reducer 33, and the pump 41. For example, the equipment drive control unit 58 controls the rotation speed of the compressor 31, the valve opening degree if the pressure reducer 33 is a valve, the rotation speed of the pump 41, etc., thereby controlling the pressure, temperature, flow rate, etc. of the refrigerant circulating through the refrigerant circuit 3 or the heat exchange fluid circulating through the fluid circuit 4. In addition, when the equipment drive control unit 58 receives a command from the abnormality processing unit 57 to perform an emergency stop when an abnormality occurs, it may perform an emergency stop of each equipment provided in the refrigerant circuit 3 and the fluid circuit 4 based on this command.

[0041] (Storage part) The storage unit 6 is composed of a memory device such as a semiconductor memory or a hard disk drive. The storage unit 6 stores each calculation formula used by the physical property value calculation unit 53 when calculating physical property values ​​such as density and kinetic viscosity, and a flow rate calculation formula used by the flow rate calculation unit 54 when calculating the flow rate of the heat exchange fluid. The storage unit 6 also stores a plurality of data tables for obtaining each physical property value in which the temperature and the differential pressure are associated with each combination of the type and concentration of the heat exchange fluid. The data tables include, for example, a density table showing the relationship between the density and the temperature, type, and concentration of the heat exchange fluid, a viscosity table showing the relationship between the viscosity and the temperature, type, and concentration of the heat exchange fluid, a specific heat table showing the relationship between the specific heat and the temperature, type, and concentration of the heat exchange fluid, a specific gravity table showing the relationship between the specific gravity and the concentration of the heat exchange fluid, and a freezing temperature table showing the relationship between the freezing temperature and the concentration of the heat exchange fluid. Each calculation formula used by the physical property calculation unit 53 and the flow rate calculation formula used by the flow rate calculation unit 54 are derived using at least one of a plurality of data tables. The storage unit 6 may also store specifications such as dimensions of the pipe through which the heat exchange fluid flows. The storage unit 6 can communicate 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 calculations. The storage unit 6 is configured with a memory device such as a semiconductor memory or a hard disk device, and is not limited to a configuration provided in the control device 5. The storage unit 6 only needs to be provided so as to be accessible by the control device 5, and may be a cloud service, for example, online storage.

[0042] (Notification Department) The notification unit 7 is a display screen such as an LED (Light Emitting Diode) or CRT (Cathode Ray Tube) or a liquid crystal screen, and outputs information onto the screen. If the determination result is a flow rate abnormality, a display output of the flow rate abnormality is performed in response to an instruction from the abnormality determination unit 56. Furthermore, the notification unit 7 may include an audio output unit such as a speaker, and output information by audio such as an alarm instead of or in addition to the display output on the screen. Furthermore, the notification unit 7 may have a communication line and execute communication data output to a remote location.

[0043] (About flow rate calculation) The details of the calculations performed by the storage unit 6, the physical property calculation unit 53, and the flow rate calculation unit 54 will be described below. First, the physical property value calculation unit 53 uses the temperature of the heat exchange fluid obtained via the operating state information acquisition unit 51 and the setting information of the type and concentration of the heat exchange fluid received from the setting information acquisition unit 52 to calculate the density ρ of the heat exchange fluid according to the following formula (1) stored in the memory unit 6.

[0044]

number

[0045] In formula (1), ρ is the density of the heat-exchanged fluid, Tin is the temperature of the heat-exchanged fluid flowing into the heat exchanger HE, and Tout is the temperature of the heat-exchanged fluid flowing out of the heat exchanger HE. Here, ρ(t) is an approximation for the density of the heat-exchanged fluid based on a previously measured value, and t is the temperature of the heat-exchanged fluid. The approximation ρ(t) will be described in detail later.

[0046] In addition, the physical property value calculation unit 53 calculates the viscosity μ of the heat exchange fluid using the temperature of the heat exchange fluid obtained via the operating state information acquisition unit 51 and the setting information of the type and concentration of the heat exchange fluid received from the setting information acquisition unit 52, according to the following formula (2) stored in the memory unit 6.

[0047]

number

[0048] In formula (2), μ is the viscosity of the heat-exchanged fluid, Tin is the temperature of the heat-exchanged fluid flowing into the heat exchanger HE, and Tout is the temperature of the heat-exchanged fluid flowing out of the heat exchanger HE. Here, μ(t) is an approximation for the viscosity of the heat-exchanged fluid based on a previously measured actual value, and t is the temperature of the heat-exchanged fluid. The approximation μ(t) will be described in detail later.

[0049] The physical property calculation unit 53 further calculates the kinetic viscosity ν of the heat exchange fluid according to the following formula (3) stored in the memory unit 6, using the density ρ and viscosity μ obtained by formulas (1) and (2).

[0050]

number

[0051] In this manner, the physical property value calculation unit 53 calculates the density ρ, the viscosity μ, and the kinetic viscosity ν, which are the physical property values ​​of the heat exchange fluid, using each calculation formula stored in the storage unit 6. In addition, the physical property value calculation unit 53 outputs the density ρ and the kinetic viscosity ν to the flow rate calculation unit 54.

[0052] Next, the flow rate calculation unit 54 calculates the flow rate Q of the heat exchange fluid according to the following formula (4) stored in the memory unit 6, using the density and kinetic viscosity of the heat exchange fluid calculated by the physical property calculation unit 53, and the differential pressure calculated from 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.

[0053]

number

[0054] In the formula (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, ν is the kinetic viscosity of the heat exchange fluid, and the predetermined values ​​α, β, and γ are values ​​obtained in advance by actual measurement. Here, the specific details of the means for setting the predetermined values ​​α, β, and γ will be described later.

[0055] As described above, the physical property value calculation unit 53 calculates the density and kinetic viscosity of the heat-exchanged fluid using the temperatures measured by the temperature sensors T1, T2 and the setting information (type and concentration of the heat-exchanged fluid) acquired by the setting information acquisition unit 52. Furthermore, the flow rate calculation unit 54 calculates the flow rate of the heat-exchanged fluid by using the density and kinetic viscosity of the heat-exchanged fluid calculated by the physical property value calculation unit 53, and the differential pressure calculated from the pressure of the heat-exchanged fluid flowing into the heat exchanger HE and the pressure of the heat-exchanged fluid flowing out of the heat exchanger HE, for a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters.

[0056] According to this method, the flow rate of the heat exchange fluid can be grasped without providing a flow meter, i.e., while suppressing an increase in the cost of the refrigeration cycle apparatus 2. The flow rate of the heat exchange fluid can be accurately calculated without being bound by the type and concentration of the heat exchange fluid arbitrarily set by the user. Furthermore, since the flow rate of the heat exchange fluid can be grasped based on the temperature, differential pressure, type, and concentration of the heat exchange fluid flowing through the fluid circuit 4, the flow rate of the heat exchange fluid can be grasped even when the refrigerant circuit 3 on the refrigerant side is not driven.

[0057] (Flow rate calculation in refrigeration cycle equipment) Next, a description will be given of an example of a flow rate calculation process of the heat exchange fluid in the refrigeration cycle apparatus 2. Fig. 3 is a flowchart showing an example of a procedure of a flow rate calculation process of the heat exchange fluid in the refrigeration cycle apparatus 2 according to an embodiment of the present disclosure.

[0058] First, as a preliminary preparation for the flow rate calculation process of the heat exchange fluid, the predetermined values ​​α, β, and γ are obtained by measuring the actual fluid (S101). Next, the type and concentration of the heat exchange fluid used in the refrigeration cycle device 2 are set by the user (S102).

[0059] Next, the pressures measured by the pressure sensors P1 and P2 are acquired by the operating state information acquisition unit 51. Furthermore, the temperatures measured by the temperature sensors T1 and T2 are acquired by the operating state information acquisition unit 51 (S103).

[0060] Next, the flow rate calculation unit 54 calculates the pressure difference Δp between the pressure of the heat-exchanged fluid flowing into the heat exchanger HE and the pressure of the heat-exchanged fluid flowing out of the heat exchanger HE (S104). Next, the physical property calculation unit 53 calculates the density ρ from the type and concentration of the heat-exchanged fluid and the integral average of the inlet and outlet temperatures of the heat exchanger HE (S105).

[0061] Next, the physical property value calculation unit 53 calculates the viscosity μ from 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 kinetic viscosity ν from the density ρ and the viscosity μ (S107).

[0062] Finally, the flow rate calculation unit 54 calculates the flow rate Q from the differential pressure Δp, density ρ, kinetic viscosity ν, and predetermined values ​​α, β, and γ of the heat exchange fluid (S108).

[0063] As described above, by calculating the flow rate of the heat exchange fluid by the flow rate calculation unit 54, the flow rate of the heat exchange fluid can be grasped without providing a flow meter, that is, while suppressing an increase in the cost of the refrigeration cycle apparatus 2. Also, the flow rate of the heat exchange fluid can be accurately calculated without being bound by the type and concentration of the heat exchange fluid arbitrarily set by the user. Furthermore, since the flow rate of the heat exchange fluid can be grasped based on the temperature, differential pressure, type and concentration of the heat exchange fluid flowing through the fluid circuit 4, the flow rate of the heat exchange fluid can be grasped even in a state where the refrigerant circuit 3 on the refrigerant side is not driven.

[0064] Furthermore, in the flow shown in FIG. 3, steps may be added without departing from the gist of the present disclosure. Also, for example, after step S108, a step may be added in which the abnormality determination section 56 determines whether or not there is an abnormality in the flow rate of the heat exchange fluid based on the calculation result of the flow rate calculation section 54.

[0065] Furthermore, for example, after step S108, a step of performing feedback control on each of the compressor 31, the pressure reducer 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. Furthermore, each process in the flow shown in FIG. 3 may be repeatedly executed at predetermined intervals while the fluid circuit 4 is in operation.

[0066] (Procedure for deriving each formula) The inventors have derived equations for calculating the density, kinetic viscosity and flow rate of the heat exchange fluid using acquired information on the heat exchange fluid, in order to calculate the flow rate of the heat exchange fluid, as described above. The derivation procedure for each equation will be described below.

[0067] [Step (1) Actual machine measurement] First, experimental measurements are carried out in advance on an actual device to ascertain the relationship between the flow rate of the heat-exchanged fluid and each parameter. Specifically, the pump 41 of the fluid circuit 4 is operated without refrigerant operation, i.e., without operating the refrigerant circuit 3, and the flow rate of the heat-exchanged fluid and the inlet and outlet temperatures of the heat exchanger HE are measured to obtain the flow rate-pressure loss (differential pressure) characteristics of the heat-exchanged fluid. FIG. 4 is a graph showing the results of actual measurements of the flow rate-pressure loss characteristics of the heat-exchanged fluid. In FIG. 4, the horizontal axis is the flow rate of the heat-exchanged fluid, and the vertical axis is the differential pressure of the heat-exchanged fluid. In FIG. 4, the solid line, dashed line, and dashed line graphs are for the same type and concentration of the heat-exchanged fluid, and only the temperature of the heat-exchanged fluid is different. According to FIG. 4, the difference in flow rate between the inlet temperature of the heat exchange fluid of -15℃ and that of 15℃ is about 5m 3 For the physical properties of the heat exchange fluid, technical documents such as a data sheet from the manufacturer of the heat exchange fluid (for example, see FIG. 5) may be referenced.

[0068] [Step (2) Deriving approximate equations for the physical properties of the heat exchange fluid and the temperature inlet / outlet of the heat exchanger] Next, using technical data from the manufacturer of the heat exchange fluid, 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. Fig. 6 is a graph showing the temperature of the heat-exchanged fluid and an approximation formula for density created using technical documents from the manufacturer of the heat-exchanged fluid. In Fig. 6, the horizontal axis is the temperature of the heat-exchanged fluid, and the vertical axis is the density of the heat-exchanged fluid. Fig. 7 is a graph showing the temperature of the heat-exchanged fluid and an approximation formula for viscosity created using technical documents from the manufacturer of the heat-exchanged fluid. In Fig. 7, the horizontal axis is the temperature of the heat-exchanged fluid, and the vertical axis is the viscosity of the heat-exchanged fluid.

[0069] As shown in Fig. 6, the change in density with respect to the temperature of the heat-exchanged fluid is approximately linear. For this reason, a quadratic approximation equation can provide sufficient prediction accuracy for the change in density with respect to the temperature of the heat-exchanged fluid. Specifically, the density with respect to the temperature of the heat-exchanged fluid is calculated by the following equation (5). In equation (5), ρ(t) is a function of the density of the heat-exchanged fluid, ρ0 is a constant calculated when the approximation equation is created, ρ1 and ρ2 are coefficients calculated when the approximation equation is created, and t is the temperature of the heat-exchanged fluid.

[0070]

number

[0071] Also, as shown in Fig. 7, the change in viscosity of the heat-exchanged fluid with respect to temperature is not approximately linear as in Fig. 6. For this reason, the change in viscosity of the heat-exchanged fluid with respect to temperature is expressed by a fifth-order approximation equation since the amount of change with respect to temperature is large. The density of the heat-exchanged fluid with respect to temperature is calculated by the following equation (6). In equation (6), μ(t) is a function of the density of the heat-exchanged fluid, μ0 is a constant calculated when the approximation equation is created, μ1, μ2, μ3, μ4, and μ5 are coefficients calculated when the approximation equation is created, and t is the temperature of the heat-exchanged fluid.

[0072]

number

[0073] Here, when actually calculating physical property values ​​during refrigerant operation in the refrigerant circuit 3, the temperature difference between the inlet temperature and outlet temperature of the heat exchanger HE in the fluid circuit 4 is large, up to 10°C difference, so the average value of the inlet temperature and outlet temperature of the heat exchanger HE is used. As a method for calculating the average value, for example, a highly accurate integral average value is used. As a result, using formula (5), formula (1) for calculating the density of the heat-exchanged fluid is derived. Similarly, using formula (6), formula (2) for calculating the density of the heat-exchanged fluid is derived.

[0074] [Step (3) Obtaining dimensionless characteristics] Based on the data acquired in the above-mentioned step (1), the Reynolds number and pressure loss / dynamic pressure are calculated. Here, the Reynolds number Re is calculated by the following formula (7). Furthermore, the pressure loss / dynamic pressure is calculated by the following formula (8). In formulas (7) and (8), d is the inner diameter of the pipe through which the heat exchange fluid flows, U is the average flow velocity in the pipe through which the heat exchange fluid flows, and ν is the kinetic viscosity of the heat exchange fluid as described in formula (3). Furthermore, the average flow velocity in the pipe U is expressed as U=4Q / πd, where Q is the flow rate of the heat exchange fluid. 2 It is calculated by:

[0075]

number

[0076]

number

[0077] Then, a dimensionless characteristic graph is created based on the relationship between the calculated Reynolds number and pressure loss / dynamic pressure. FIG. 8 is a dimensionless characteristic graph illustrating the relationship between the Reynolds number of the heat exchange flow and pressure loss / dynamic pressure. In FIG. 8, the horizontal axis is the Reynolds number, and the vertical axis is the pressure loss / dynamic pressure. By creating a dimensionless characteristic graph in this manner, each condition with different temperatures of the heat exchange fluid can be displayed on the same scale. Furthermore, based on the dimensionless characteristic graph, an approximation equation between the Reynolds number and pressure loss / dynamic pressure is created by power approximation.

[0078] [Step (4) Deriving the flow rate calculation formula (formula (4)) of the heat exchange fluid] Next, the approximation equation of the Reynolds number and the pressure loss / dynamic pressure created in step (3) is expressed as the following equation (9).

[0079]

number

[0080] Substituting equation (7) and the average flow velocity in the pipe U into equation (9) and rearranging the equation, we obtain the following equation (10). Note that a and n are constants derived from the power approximation of the Reynolds number and pressure loss / dynamic pressure.

[0081]

number

[0082] From equation (10), a, d, and n are all constants, so by rearranging equation (10), the given value α is given as α=(π / 4)(2 / a) 1 / (n+2) d (n+4 / n+2) , β=-n, γ=1 / (n+2), the equation can be transformed into the above equation (4). Through the above steps, the equations for calculating density and viscosity used by the physical property value calculation unit 53 and the flow rate equation used by the flow rate calculation unit 54 are derived. Moreover, the inventors have confirmed that by using the formula (4) derived in this way, it is possible to calculate a flow rate of the heat exchange fluid that is close to the actually measured value.

[0083] As described above, in the refrigeration cycle apparatus 2 of the present disclosure, the flow rate calculation unit 54 calculates the differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger HE and the pressure of the heat-exchanged fluid flowing out of the heat exchanger HE, and calculates the flow rate of the heat-exchanged fluid by using the density, kinetic viscosity, and differential pressure of the heat-exchanged fluid calculated by the physical property calculation unit 53 for a flow rate calculation formula including the density, kinetic viscosity, and differential pressure as parameters. This makes it possible to grasp the flow rate of the heat-exchanged fluid without providing a flow meter, that is, while suppressing an increase in the cost of the refrigeration cycle apparatus 2. In addition, since the flow rate of the heat-exchanged fluid can be grasped based on the temperature, differential pressure, type, and concentration of the heat-exchanged fluid flowing through the fluid circuit 4, the flow rate of the heat-exchanged fluid can be grasped even in a state in which the refrigerant circuit 3 on the refrigerant side is not driven.

[0084] The flow rate calculation formula is derived from an approximation formula showing the relationship between the Reynolds number of the heat exchange fluid and the pressure loss / dynamic pressure, which is derived using multiple data in which the temperature and differential pressure are associated with each combination of the type and concentration of the heat exchange fluid. In other words, the flow rate of the heat exchange fluid is calculated using a predetermined non-dimensional calculation formula. This makes it possible to accurately calculate the flow rate of the heat exchange fluid without being limited by the type or concentration of the heat exchange fluid that the user arbitrarily sets.

[0085] In addition, the flow rate calculation of the heat-exchanged fluid according to the present disclosure can reduce the number of data points to be acquired at the timing of performing the flow rate calculation. For example, in the case where a differential pressure gauge for measuring the differential pressure between the inlet and outlet of the heat exchanger HE is provided in the fluid circuit 4 instead of the pressure sensors P1 and P2, the number of data points to be acquired at the time of flow rate calculation is two points of data, namely, the differential pressure measured by the differential pressure gauge and the inlet temperature of the heat exchanger HE. In addition, even if a differential pressure gauge is not provided and each temperature of the inlet and outlet of the heat exchanger HE is measured, four points of data, namely, 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, are acquired. In this way, the flow rate calculation according to the present disclosure has fewer data points compared to the conventional method of acquiring the pressure and temperature of the refrigerant side, the rotation speed of the compressor 31 provided in the refrigerant circuit 3, and the like, and therefore, the software capacity is prevented from being compressed in the calculation process. In addition, since the number of data points is small, a program can be easily created and the occurrence of design errors can be suppressed.

[0086] In addition, the flow rate of the heat exchange fluid according to the present disclosure can be calculated by acquiring data from at least two points. Here, for example, if the failure probability of each of the multiple data acquisition units (e.g., sensors) is equal to n, the failure probability when there are two data acquisition units is 1-(1-n). 2 Similarly, the probability of failure when there are two data acquisition units is 1-(1-n) 6 In this way, regardless of the value of n, a smaller number of data acquisition points can reduce the probability of insufficient data for flow rate calculation. In other words, a smaller number of data acquisition points can reduce the probability of flow rate calculation being impossible.

[0087] (Another embodiment: Detection of concentration change of heat exchange fluid) The flow rate calculation of the heat exchange fluid has been described for the refrigeration cycle apparatus 2 in the present disclosure. Below, a method for calculating the capacity of the refrigeration cycle apparatus 2 and the concentration change of the heat exchange fluid using the above-mentioned configuration will be described. Fig. 9 is a diagram showing a schematic configuration of a refrigeration cycle system 10 according to this embodiment. In the configuration diagram of Fig. 1, the pressure sensors P1, P2 and the temperature sensors T1, T2 are provided only in the fluid circuit 4, but in this embodiment, as shown in Fig. 9, the refrigerant circuit 3 is also provided with pressure sensors P3, P4 and temperature sensors T3, T4 in the same manner as the fluid circuit 4.

[0088] The pressure sensors P3 and P4 are provided, for example, at the inlet and outlet, respectively, of the compressor 31 in the refrigerant circuit 3. The pressure sensor P3 measures the pressure of the refrigerant flowing into the compressor. The pressure sensor P4 measures the pressure of the refrigerant flowing out from the compressor 31. The measured pressures are transmitted to the control device 5 and used for calculating the heat exchange amount of the refrigerant circuit 3, which will be described later.

[0089] The temperature sensors T3 and T4 are provided, for example, at the inlet and outlet, respectively, of the heat exchanger HE in the refrigerant circuit 3. The temperature sensor T3 measures the temperature of the heat-exchanged fluid flowing into the heat exchanger HE. The temperature sensor T4 measures the temperature of the heat-exchanged fluid flowing out of the heat exchanger HE. The measured temperatures are sent to the control device 5 and used to calculate the heat exchange amount of the refrigerant circuit 3, which will be described later.

[0090] The control device 5 in this embodiment calculates the enthalpies 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 the enthalpy difference between the inlet and outlet of the heat exchanger HE. Note that, for the pressure used to calculate the enthalpy difference between the inlet and outlet of the heat exchanger HE, a value that takes into account the pressure loss generated by the heat exchanger HE with respect to the measurement result measured by the pressure sensor P3 may be used. In addition, in the present disclosure, an example in which each enthalpy is calculated using the pressure measured by the pressure sensor P3 provided on the inlet side of the compressor 31 will be described, but the present disclosure is not limited to this example, and more preferably, each enthalpy may be calculated using the pressure measured by a pressure sensor provided on the inlet side of the heat exchanger HE. 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 explanation will be omitted. Furthermore, the abnormality determination unit 56 in this embodiment is capable of two-way communication with the capacity calculation unit 55, and has a function of detecting a change in concentration of the heat exchange fluid using the calculation results of the capacity calculation unit 55. Furthermore, the flow rate calculation unit 54 in this embodiment is capable of calculating the flow rate of the refrigerant circulating through the refrigerant circuit 3, and the capacity calculation unit 55 is capable of calculating the capacity of the refrigerant circuit 3. The other configurations are similar to those shown in FIG.

[0091] First, when the refrigerant and the heat-exchanged fluid exchange heat through the heat exchanger HE, the amount of heat exchanged in the heat exchanger HE changes depending on the operating state of the refrigeration cycle apparatus 2. The amount of heat exchanged of the refrigerant in the heat exchanger HE and the amount of heat exchanged of the heat-exchanged fluid in the heat exchanger HE are equal if the concentration of the heat-exchanged fluid is normal. For this reason, if the amount of heat exchanged in the refrigerant circuit 3 and the amount of heat exchanged in the fluid circuit 4 are not equal, it can be considered that the concentration of the heat-exchanged fluid has changed.

[0092] In order to check the change in concentration of the heat exchange fluid, first, the capacity calculation unit 55 calculates the first heat exchange amount Qr in the refrigerant circuit 3 and the second heat exchange amount Qb in the fluid circuit 4 using the calculation results of the state amount calculation unit 60, the physical property value calculation unit 53, and the flow rate calculation unit 54 described later. Then, the abnormality determination unit 56 compares the calculated heat exchange amounts to detect the occurrence of a change in concentration of the heat exchange fluid based on the difference between the first heat exchange amount and the second heat exchange amount. In this way, in this embodiment, the abnormality determination unit 56 functions as a concentration change detection unit that detects a change in concentration of the heat exchange fluid. Not limited to this example, the control device 5 may be provided with a concentration change detection unit independent of the abnormality determination unit 56.

[0093] A method for calculating the first heat exchange amount Qr, which is the heat exchange amount in the refrigerant circuit 3, will be described below. First, the state quantity calculation unit 60 calculates the enthalpy difference between the inlet and outlet of the heat exchanger HE using the operating state information (pressure, temperature) acquired by the operating state information acquisition unit 51. Furthermore, the flow rate calculation unit 54 calculates the flow rate of the refrigerant by using the displacement and rotation speed of the compressor 31 acquired by the operating state information acquisition unit 51 and the density of the refrigerant calculated by the physical property value calculation unit 53. Note that, in order to derive the enthalpy difference between the inlet and outlet of the heat exchanger HE, the memory unit 6 stores a ph diagram of the refrigerant circulating through the refrigerant circuit 3, and this ph diagram may be used.

[0094] Next, the capacity calculation unit 55 calculates the first heat exchange amount Qr by the following formula (11) using the calculation results of the state quantity calculation unit 60 and the flow rate calculation unit 54. In formula (11), Gr is the flow rate of the refrigerant calculated by the flow rate calculation unit 54. Also, Δh is the enthalpy difference between the inlet and outlet of the heat exchanger HE calculated by the state quantity calculation unit 60.

[0095]

number

[0096] Next, a method for calculating the second heat exchange amount Qb, which is the heat exchange amount in the fluid circuit 4, will be described. First, the physical property value calculation unit 53 calculates the density, specific heat, kinetic viscosity, and temperature difference of the heat-exchanged fluid between the inlet and outlet of the heat exchanger HE, using the operating state information (pressure, temperature) acquired by the operating state information acquisition unit 51 and the setting information (type and concentration) of the heat-exchanged fluid acquired by the setting information acquisition unit 52. Furthermore, the flow rate calculation unit 54 calculates the flow rate of the heat-exchanged fluid by using the physical property values ​​calculated by the physical property value calculation unit 53 and the pressure difference between the inlet and outlet of the heat exchanger HE acquired by the operating state information acquisition unit 51. Here, the flow rate of the heat exchange fluid in detecting a change in the concentration of the heat exchange fluid may be calculated using an approximate equation derived from the physical property values ​​of the heat exchange fluid calculated using the setting information (type and concentration) and temperature of the heat exchange fluid. Note that the pressure difference between the inlet and outlet of the heat exchanger HE of the fluid circuit 4 may be a value measured using a differential pressure gauge.

[0097] Next, the capacity calculation unit 55 calculates the first heat exchange amount Qr by the following formula (12) using the calculation results of the physical property calculation unit 53 and the flow rate calculation unit 54. In formula (12), Gb is the flow rate of the heat-exchanged fluid calculated by the flow rate calculation unit 54. Also, ρ is the density of the heat-exchanged fluid calculated by the physical property calculation unit 53, V is the flow rate of the heat-exchanged fluid calculated by the flow rate calculation unit 54, c is the specific heat of the heat-exchanged fluid calculated by the physical property calculation unit 53, and ΔT is the temperature difference of the heat-exchanged fluid between the inlet and outlet of the heat exchanger HE calculated by the physical property calculation unit 53.

[0098]

number

[0099] Here, if 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 means that the concentration of the heat exchange fluid has changed since the beginning of operation, and the density ρ, flow rate V, and specific heat c of the heat exchange fluid have changed in the fluid circuit 4. In other words, the occurrence of a change in the concentration of the heat exchange fluid can be detected from the difference between the first heat exchange amount Qr and the second heat exchange amount Qb.

[0100] In addition, when the abnormality judgment unit 56 detects a change in the concentration of the heat exchange fluid, for example, when the difference in the 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 equipment drive control unit 58 may stop operation of each equipment provided in the refrigeration cycle device 2.

[0101] In addition, when the abnormality judgment unit 56 detects a change in the concentration of the heat exchange fluid, in addition to stopping the operation of each device equipped in the refrigeration cycle device 2, the concentration change may be calculated and a 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.

[0102] When a difference occurs between the first heat exchange amount Qr and the second heat exchange amount Qb, that is, when a difference occurs between the second heat exchange amount Qb at the beginning of operation of the refrigeration cycle apparatus 2 and the current second heat exchange amount Qb, the second heat exchange amount Qb changes due to changes in each of the density ρ, the flow rate V, and the specific heat c in formula (12). Therefore, the concentration of the heat exchange fluid can be calculated using the changes in each of the density ρ, the flow rate V, and the specific heat c from the beginning of operation of the refrigeration cycle apparatus 2 to the present.

[0103] Here, FIG. 10 is a graph illustrating the characteristics of specific gravity corresponding to the type and concentration of the heat-exchanged fluid. In FIG. 10, the horizontal axis is the concentration of the heat-exchanged fluid, and the vertical axis is the specific gravity of the heat-exchanged fluid. Here, specific gravity is the ratio between the density of the heat-exchanged fluid and the density of a standard substance (e.g., water). Therefore, there is a correlation between density and specific gravity, and specific gravity also changes as density changes. That is, the capacity calculation unit 55 calculates the change in specific gravity corresponding to the change in density, and can calculate the concentration after the change from the specific gravity of the heat-exchanged fluid after the change using the relationship illustrated in FIG. 10. Furthermore, the freezing temperature of the heat-exchanged fluid can be derived from the concentration of the heat-exchanged fluid, as illustrated in FIG. 11. Therefore, the capacity calculation unit 55 can calculate not only the change in concentration of the heat-exchanged fluid but also the change in freezing temperature of the heat-exchanged fluid by calculating the difference between the first heat exchange amount Qr and the second heat exchange amount Qb.

[0104] In this way, the capacity calculation unit 55 can calculate the concentration and freezing temperature of the heat exchange fluid that have changed since the beginning of operation of the refrigeration cycle apparatus 2, and can therefore calculate a correction amount for at least one of the setting information and the freezing temperature of the heat exchange fluid. The correction amount calculated by the capacity calculation unit 55 may be notified to the user by the notification unit 7.

[0105] Even when a change in the concentration of the heat exchange fluid occurs, for example, when the concentration changes due to evaporation or moisture absorption, the capacity calculation unit 55 can calculate a correction amount for the concentration of the heat exchange fluid to make the capacity of the refrigeration cycle apparatus 2 equivalent to that at the beginning of operation. Furthermore, the calculation result is notified to the user by the notification unit 7, so that the user can grasp the change in the concentration of the heat exchange fluid and can correct the concentration of the heat exchange fluid to make the refrigeration cycle apparatus 2 output a predetermined capacity.

[0106] In addition, even if the concentration of the heat exchange fluid changes due to evaporation or moisture absorption of the heat exchange fluid after the equipment is installed, an abnormality is notified, and the refrigeration cycle device 2 is prevented from continuing to operate when the physical properties of the heat exchange fluid are abnormal, thereby preventing the occurrence of breakdowns and accidents. Furthermore, by performing regular maintenance, it is possible to save the effort of checking the concentration of the heat exchange fluid.

[0107] In the above example, the concentration and freezing temperature of the heat-exchanged fluid are calculated by the capacity calculation unit 55, but instead, a data table showing the relationship between the concentration and freezing temperature of the heat-exchanged fluid and a data table showing the relationship between the concentration and freezing temperature of the heat-exchanged fluid may be stored in the storage unit 6. In this case, the capacity calculation unit 55 may determine the correction amounts for the concentration and freezing temperature of the heat-exchanged fluid by referring to each data table.

[0108] (Additional Notes) Although the present disclosure has been described above using the embodiments, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. Various modifications or improvements can be made to the above embodiments without departing from the gist of the present disclosure, and the forms in which such modifications or improvements are made are also included in the technical scope of the present disclosure. In addition, the above embodiments may be appropriately combined.

[0109] The control device, the refrigeration cycle device including the control device, the refrigeration cycle system including the control device, the control method, and the control program described in the above-described embodiments can be understood, for example, as follows. 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-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger, and includes a temperature acquisition unit (51) that acquires the temperature of the heat-exchanged fluid, a pressure acquisition unit (51) that acquires the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, a setting information acquisition unit (52) that acquires setting information on the type and concentration of the heat-exchanged fluid, and The heat exchanger includes a physical property value calculation unit (53) that calculates the density and kinetic viscosity of the heat exchange fluid using the temperature and the setting information acquired by the setting information acquisition unit, and a flow rate calculation unit (54) that 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, kinetic viscosity, and differential pressure of the heat exchange fluid calculated by the physical property value calculation unit for a flow rate calculation equation including density, kinetic viscosity, and differential pressure as parameters.

[0110] According to the control device of the present disclosure, the temperature acquisition unit and the pressure acquisition unit acquire the temperature and differential pressure of the heat-exchanged fluid, and acquire the setting information of the type and concentration of the heat-exchanged fluid. The physical property value calculation unit calculates the density and kinetic viscosity of the heat-exchanged fluid 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. Furthermore, the flow rate calculation unit calculates the differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and calculates the flow rate of the heat-exchanged fluid by using the density, kinetic viscosity, and differential pressure of the heat-exchanged fluid calculated by the physical property value calculation unit for a flow rate calculation formula including the density, kinetic viscosity, and differential pressure as parameters. This makes it possible to grasp the flow rate of the heat-exchanged fluid without providing a flow meter, that is, while suppressing an increase in the cost of the refrigeration cycle device. In addition, since the flow rate of the heat exchange fluid can be grasped based on the temperature, differential pressure, type and concentration of the heat exchange fluid, the flow rate of the heat exchange fluid can be grasped even when the refrigerant circuit on the refrigerant side is not driven.

[0111] In the control device of the first aspect of the second aspect of the present disclosure, the flow rate calculation formula is a calculation formula derived from an approximation formula showing the relationship between the Reynolds number of the heat exchange fluid and pressure loss / dynamic pressure, which is derived using a plurality of data in which temperature and differential pressure correspond to each combination of type and concentration of the heat exchange fluid.

[0112] According to the control device of the present disclosure, the flow rate calculation formula is a calculation formula derived from an approximation formula showing the relationship between the Reynolds number of the heat exchange fluid and the pressure loss / dynamic pressure, which is derived using a plurality of data in which the temperature and the differential pressure are associated with each combination of the type and concentration of the heat exchange fluid. In other words, the flow rate of the heat exchange fluid is calculated using a predetermined calculation formula that has been made dimensionless. This makes it possible to accurately calculate the flow rate of the heat exchange fluid without being limited by the type or concentration of the heat exchange fluid that is arbitrarily set by the user.

[0113] In the control device according to the third aspect of the present disclosure, in the first or second aspect, the temperature acquisition unit acquires a measurement result from a first temperature measuring unit (T1) that measures a first temperature of the heat exchange fluid flowing into the heat exchanger and a measurement result from a second temperature measuring 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.

[0114] 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 the temperature of the heat-exchanged fluid flowing into the heat exchanger and the measurement result of the second temperature measurement unit that measures the temperature of the heat-exchanged fluid flowing out of the heat exchanger, and the physical property value calculation unit calculates the average of the first temperature and the second temperature measurement. This makes it possible to more accurately acquire the temperature of the heat-exchanged fluid, and therefore to more accurately calculate the flow rate of the heat-exchanged fluid.

[0115] The control device according to a fourth aspect of the present disclosure, in any of the first to third aspects, includes an equipment drive control unit (58) that controls a compressor (31) that compresses the refrigerant, a pressure reducer (33) that depressurizes the refrigerant, and a pump (41) that delivers the heat exchange fluid, using a calculation result of the flow rate calculation unit as one of parameters.

[0116] According to the control device of the present disclosure, the control device includes an equipment drive control unit that controls a compressor that compresses a refrigerant, a pressure reducer that decompresses the refrigerant, and a pump that delivers a heat exchange fluid based on the calculation result of the flow rate calculation unit, thereby making it possible to appropriately control the state of the refrigerant flowing through the heat exchanger and the flow rate of the heat exchange fluid.

[0117] The control device according to a fifth aspect of the present disclosure, in any of the first to fourth aspects, includes an abnormality determination unit (56) that determines whether or not there is an abnormality in the flow rate of the heat exchange fluid based on the calculation result of the flow rate calculation unit.

[0118] According to the control device of the present disclosure, the control device includes an abnormality determination unit that determines whether or not there is an abnormality in the flow rate of the heat exchange fluid based on the calculation result of the flow rate calculation unit, thereby making it possible to determine an abnormality in the flow rate of the heat exchange fluid and to prevent the refrigeration cycle device from continuing to operate in an abnormal state.

[0119] A control device according to a sixth aspect of the present disclosure, in any of the first to fifth aspects, includes a capacity calculation unit (55) that calculates a first heat exchange amount, which is the heat exchange amount of the refrigerant in the heat exchanger, and a second heat exchange amount, which is the heat exchange amount of the heat exchanged fluid in the heat exchanger, and a concentration change detection unit (57) that detects a change in concentration of the heat exchanged fluid based on the difference between the first heat exchange amount and the second heat exchange amount.

[0120] According to the control device of the present disclosure, the capacity calculation unit calculates a first heat exchange amount, which is the heat exchange amount of the refrigerant in the heat exchanger, and a second heat exchange amount, which is the heat exchange amount of the heat-exchanged fluid in the heat exchanger, and the concentration change detection unit detects a change in concentration of the heat-exchanged fluid based on the difference between the first heat exchange amount and the second heat exchange amount. This makes it possible to prevent the refrigeration cycle device from continuing to operate in a state where the physical properties of the heat-exchanged fluid are abnormal, and to prevent the occurrence of breakdowns and accidents. In addition, it is possible to save the effort of checking the concentration of the heat-exchanged fluid by performing regular maintenance.

[0121] A refrigeration cycle apparatus according to a seventh aspect of the present disclosure includes the control device (5) according to any one of the first to sixth aspects.

[0122] A refrigeration cycle system according to an eighth aspect of the present disclosure includes the refrigeration cycle apparatus (2) according to the seventh aspect, and a fluid circuit (4) through which the heat exchange fluid circulates.

[0123] 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-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger (HE), the control method including a temperature acquisition step of acquiring a temperature of the heat-exchanged fluid, a pressure acquisition step of acquiring a pressure of the heat-exchanged fluid flowing into the heat exchanger and a pressure of the heat-exchanged fluid flowing out of the heat exchanger, a setting information acquisition step of acquiring setting information on a type and concentration of the heat-exchanged fluid, and a temperature acquisition step of acquiring the temperature acquired by the temperature acquisition step. and a flow rate calculation step of calculating a differential pressure between the pressure of the heat exchanger flowing into the heat exchanger and the pressure of the heat exchanger flowing out of the heat exchanger, and calculating a flow rate of the heat exchanger by using the density, kinetic viscosity, and differential pressure of the heat exchanger fluid calculated by the physical property calculation step for a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters.

[0124] 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-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger (HE), the control program including a temperature acquisition process for acquiring a temperature of the heat-exchanged fluid, a pressure acquisition process for acquiring a pressure of the heat-exchanged fluid flowing into the heat exchanger and a pressure of the heat-exchanged fluid flowing out of the heat exchanger, a setting information acquisition process for acquiring setting information on the type and concentration of the heat-exchanged fluid, and a temperature acquisition process for acquiring the temperature acquired by the temperature acquisition process. The computer is caused to execute a physical property calculation process that calculates the density and kinetic viscosity of the heat exchange fluid using the setting information acquired by the setting information acquisition process, and a flow rate calculation process that 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, kinetic viscosity, and differential pressure of the heat exchange fluid calculated by the physical property calculation process for a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters. [Explanation of symbols]

[0125] 1 Refrigeration cycle system 2 Refrigeration cycle equipment 3 Refrigerant circuit 4 Fluid circuit 5. Control device 5a CPU 5b Auxiliary storage device (ROM) 5c Main memory (RAM) 5d Communication Interface 5e Input / output section 5F Bus 6 Memory section 7. Notification Department 10 Refrigeration cycle system 31 Compressor 32 Heat exchanger 33 Pressure reducer 41 Pump 42 Equipment load 51 Operation status information acquisition unit 52 Setting information acquisition unit 53 Physical property calculation section 54 Flow rate calculation section 55 Ability Calculation Unit 56 Abnormality determination section 57 Abnormality Processing Unit 58 Device drive control unit 60 State quantity calculation unit HE heat exchanger P1~P4 Pressure sensors T1~T4 Temperature sensors

Claims

1. A control device for a refrigeration cycle device that supplies a heat-exchanged fluid at a desired temperature by performing heat exchange between a refrigerant and a heat-exchanged fluid in a heat exchanger, A temperature acquisition unit that acquires a temperature of the heat exchange fluid; a pressure acquisition unit that acquires a pressure of the heat-exchanged fluid flowing into the heat exchanger and a pressure of the heat-exchanged fluid flowing out of the heat exchanger; A setting information acquisition unit that acquires setting information on the type and concentration of the heat exchange fluid; a physical property value calculation unit that calculates a density and a kinetic viscosity of the heat exchange fluid using the temperature acquired by the temperature acquisition unit and the setting information acquired by the setting information acquisition unit; a flow rate calculation unit that calculates a differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and calculates a flow rate of the heat-exchanged fluid by using the density and kinetic viscosity of the heat-exchanged fluid calculated by the physical property value calculation unit and the differential pressure in a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters; A control device comprising:

2. The control device according to claim 1, wherein the flow rate calculation formula is a calculation formula derived from an approximation formula showing the relationship between the Reynolds number of the heat exchange fluid and the pressure loss / dynamic pressure, which is derived using a plurality of data in which temperature and differential pressure correspond to each combination of type and concentration of the heat exchange fluid.

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

4. 2. The control device according to claim 1, further comprising an equipment drive control unit that controls a compressor that compresses the refrigerant, a pressure reducer that depressurizes the refrigerant, and a pump that delivers the heat exchange fluid, 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 whether or not there is an abnormality in the flow rate of the heat exchange fluid based on a calculation result of the flow rate calculation unit.

6. 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-exchanged fluid in the heat exchanger; a concentration change detection unit that detects a change in concentration of the heat exchange fluid based on a difference between the first heat exchange amount and the second heat exchange amount; The control device according to claim 1 .

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

8. The refrigeration cycle apparatus according to claim 7, a fluid circuit in which the heat exchange fluid circulates; A refrigeration cycle system comprising:

9. A method for controlling a refrigeration cycle device that supplies a heat exchange fluid at a desired temperature by performing heat exchange between a refrigerant and a heat exchange fluid in a heat exchanger, comprising: a temperature acquisition step of acquiring a temperature of the heat exchange fluid; a pressure acquiring step of acquiring a pressure of the heat-exchanged fluid flowing into the heat exchanger and a pressure of the heat-exchanged fluid flowing out of the heat exchanger; A setting information acquisition step of acquiring setting information on the type and concentration of the heat exchange fluid; a physical property value calculation step of calculating a density and a kinetic viscosity of the heat exchange fluid using the temperature acquired in the temperature acquisition step and the setting information acquired in the setting information acquisition step; a flow rate calculation step of calculating a differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and calculating a flow rate of the heat-exchanged fluid by using the density, kinetic viscosity, and differential pressure of the heat-exchanged fluid calculated in the physical property calculation step in a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters; The control method includes:

10. A control program for a refrigeration cycle device that supplies a heat exchange fluid at a desired temperature by performing heat exchange between a refrigerant and a heat exchange fluid in a heat exchanger, comprising: A temperature acquisition process for acquiring a temperature of the heat exchange fluid; a pressure acquisition process for acquiring a pressure of the heat-exchanged fluid flowing into the heat exchanger and a pressure of the heat-exchanged fluid flowing out of the heat exchanger; A setting information acquisition process for acquiring setting information on the type and concentration of the heat exchange fluid; a physical property calculation process for calculating a density and a kinetic viscosity of the heat exchange fluid using the temperature acquired by the temperature acquisition process and the setting information acquired by the setting information acquisition process; a flow rate calculation process for calculating a differential pressure between the pressure of the heat-exchanged fluid flowing into the heat exchanger and the pressure of the heat-exchanged fluid flowing out of the heat exchanger, and for calculating a flow rate of the heat-exchanged fluid by using the density, kinetic viscosity, and differential pressure of the heat-exchanged fluid calculated by the physical property calculation process in a flow rate calculation formula including density, kinetic viscosity, and differential pressure as parameters; A control program for causing a computer to execute the above.

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