Simulation device, simulation method, and simulation program

Abstract

This simulation device (1) executes a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit (101, 102, 103). The simulation device (1) comprises: a storage device (4); and an arithmetic device (2) that executes the simulation in accordance with a simulation program (7) stored in the storage device (4). The arithmetic device (2) acquires an initial value indicating the initial state of the refrigerant at one or more calculation points in the refrigerant circuit (101, 102, 103) and calculates, on the basis of the initial value, a related value relating to one or more configurations included in the refrigerant circuit (101, 102, 103).

Description

Simulation device, simulation method, and simulation program

[0001] The present disclosure relates to a simulation device, a simulation method, and a simulation program for performing a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit.

[0002] Techniques for simulating the refrigeration cycle of a refrigerant flowing through a refrigerant circuit have been known. For example, Japanese Patent Application Laid-Open No. 2001-133011 discloses an air conditioner diagnostic device that calculates refrigeration cycle characteristics when the refrigerant circuit is in a normal state through a cycle simulation and creates a Mollier diagram based on the calculation results.

[0003] Japanese Patent Application Laid-Open No. 2001-133011

[0004] According to the diagnostic device disclosed in Japanese Patent Laid-Open Publication No. 2001-133011 (Patent Document 1), a user, such as a developer or designer of an air conditioner, must manually input relevant values ​​related to various configurations, such as refrigerant flow rate, connecting pipe length, and pipe length, which are data required for simulation calculations. Furthermore, because a refrigerant circuit has multiple configurations, manually setting the relevant values ​​by the user may increase the time required to set the relevant values ​​or may result in errors in setting the relevant values. Furthermore, errors in setting the relevant values ​​may worsen the convergence of the simulation calculations, increasing the time required to obtain a solution or causing the calculations to diverge, resulting in an inability to obtain a solution.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a technique that can appropriately perform a simulation of a refrigeration cycle in a short period of time.

[0006] A simulation device according to the present disclosure is a device that executes a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit. The simulation device includes a storage device and a calculation device that executes the simulation in accordance with a simulation program stored in the storage device. The calculation device acquires an initial value that indicates an initial state of the refrigerant at at least one calculation point in the refrigerant circuit, and calculates a related value for at least one component included in the refrigerant circuit based on the initial value.

[0007] A simulation method according to the present disclosure is a method for performing a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit. The simulation method includes, as processing executed by a computer, a step of acquiring an initial value indicating an initial state of the refrigerant at at least one calculation point in the refrigerant circuit, and a step of calculating a related value for at least one component included in the refrigerant circuit based on the initial value.

[0008] A simulation program according to the present disclosure is a program for executing a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit, the simulation program causing a computer to execute steps of acquiring an initial value indicating an initial state of the refrigerant at at least one calculation point in the refrigerant circuit, and calculating a related value for at least one component included in the refrigerant circuit based on the initial value.

[0009] According to the present disclosure, a user can calculate a related value for at least one component included in a refrigerant circuit based on an initial value indicating an initial state of the refrigerant at at least one calculation point in the refrigerant circuit. This eliminates the need for the user to manually input the related values ​​used in the simulation, thereby avoiding an increase in the time required to set the related values ​​and the occurrence of errors in setting the related values, and enabling the user to appropriately perform a refrigeration cycle simulation in a short time.

[0010] 1 is a diagram showing the configuration of a simulation system according to Embodiment 1. FIG. 2 is a Mollier diagram used in simulating a refrigerant circuit according to Embodiment 1. FIG. 3 is a diagram for explaining an allocation data table related to a refrigerant circuit stored by a simulation device according to Embodiment 1. FIG. 4 is a diagram for explaining an example of correspondence between each calculation point of a refrigerant circuit according to Embodiment 1 and each cycle point of a Mollier diagram. FIG. 5 is a diagram showing the configuration of another refrigerant circuit according to Embodiment 1. FIG. 6 is a Mollier diagram used in simulating another refrigerant circuit according to Embodiment 1. FIG. 7 is a diagram for explaining an allocation data table related to another refrigerant circuit stored by a simulation device according to Embodiment 1. FIG. 8 is a diagram for explaining correspondence between each calculation point of another refrigerant circuit according to Embodiment 1 and each cycle point of a Mollier diagram. FIG. 9 is a diagram for explaining a modified example of correspondence between each calculation point of a refrigerant circuit according to Embodiment 1 and each cycle point of a Mollier diagram. FIG. 10 is a diagram showing the configuration of a refrigerant circuit according to Embodiment 2. FIG. 11 is a diagram for explaining an example of calculation of an initial opening degree of an expansion valve in a refrigerant circuit according to Embodiment 2. FIG. 12 is a diagram for explaining an example of calculation of an initial air flow rate of a fan or a correction value for a heat transfer coefficient in a heat exchanger in a refrigerant circuit according to Embodiment 2. FIG. 13 is a diagram for explaining an example of calculation of an initial amount of refrigerant charged in a refrigerant circuit according to Embodiment 2. 10 is a flowchart illustrating a process executed by a simulation device according to a second embodiment.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. While multiple embodiments will be described below, it is anticipated from the beginning that the configurations described in each embodiment will be appropriately combined. Note that identical or corresponding parts in the drawings will be designated by the same reference numerals, and their description will not be repeated.

[0012] First Embodiment A simulation device 1 according to a first embodiment will be described with reference to FIGS.

[0013] [Configuration of Simulation System 100] Fig. 1 is a diagram showing the configuration of a simulation system 100 according to Embodiment 1. As shown in Fig. 1, the simulation system 100 according to Embodiment 1 includes a refrigerant circuit 101 of an air conditioner to be simulated, and a simulation device 1 that executes a simulation of the refrigeration cycle of the refrigerant flowing through the refrigerant circuit 101. Note that Fig. 1 functionally shows the connection relationships and arrangement of the components in the refrigerant circuit 101, and does not necessarily show the physical spatial arrangement.

[0014] The refrigerant circuit 101 includes a compressor 10 , a condenser 20 , a fan 25 , an expansion valve 40 , an evaporator 30 , and a fan 35 .

[0015] The compressor 10 is configured to be driven and stopped under the control of a control device (not shown). Specifically, the compressor 10 changes the number of rotations per unit time, i.e., the rotational speed, and changes the amount of refrigerant discharged under the control of the control device. Various types of compressors can be used as the compressor 10, and for example, a scroll type, a rotary type, a screw type, etc. can be used as the compressor 10.

[0016] The condenser 20 is a heat exchanger configured to exchange heat between the refrigerant and the air drawn in from the outside by the fan 25 .

[0017] The fan 25 is configured to be driven and stopped under the control of the control device, and the amount of air sent to the condenser 20 is changed by changing the number of rotations per unit time, i.e., the rotation speed.

[0018] The expansion valve 40 reduces the pressure of the refrigerant that has flowed in under the control of the control device, and the refrigerant obtained by the reduced pressure flows out. The expansion valve 40 can adjust the flow rate of the refrigerant and the amount of pressure reduction by adjusting the opening degree under the control of the control device.

[0019] The evaporator 30 is a heat exchanger configured to exchange heat between the refrigerant and the air drawn in from the outside by the fan 35 .

[0020] The fan 35 is configured to be driven and stopped under the control of the control device, and the amount of air sent to the evaporator 30 is changed by changing the number of rotations per unit time, i.e., the rotation speed.

[0021] The discharge port 12 of the compressor 10 is connected to one end of the condenser 20 via pipes 71 and 72. The other end of the condenser 20 is connected to one end of the expansion valve 40 via pipes 73 and 74. The other end of the expansion valve 40 is connected to one end of the evaporator 30 via pipes 75 and 76. The other end of the evaporator 30 is connected to the suction port 11 of the compressor 10 via pipes 77 and 78.

[0022] In the refrigerant circuit 101 configured as described above, the refrigerant flows through the compressor 10, the condenser 20, the expansion valve 40, and the evaporator 30 in this order.

[0023] For example, the compressor 10 draws in low-temperature, low-pressure gas refrigerant from the evaporator 30 and compresses the drawn gas refrigerant to increase the pressure of the gas refrigerant. The compressor 10 discharges the high-temperature, high-pressure gas refrigerant obtained by the compression to the condenser 20.

[0024] The condenser 20 exchanges heat between the high-temperature, high-pressure gas refrigerant from the compressor 10 and air drawn in from the outdoors by the fan 25. The gas refrigerant that has released heat into the air through this heat exchange is condensed inside the condenser 20 to change into high-temperature, high-pressure liquid refrigerant. The high-temperature, high-pressure liquid refrigerant obtained by the condenser 20 flows out to the expansion valve 40.

[0025] The expansion valve 40 reduces the pressure of the high-temperature, high-pressure liquid refrigerant from the condenser 20. The low-temperature, low-pressure gas-liquid two-phase refrigerant obtained by the pressure reduction in the expansion valve 40 flows into the evaporator 30.

[0026] The evaporator 30 exchanges heat between the low-temperature, low-pressure gas-liquid two-phase refrigerant from the expansion valve 40 and air drawn in from the room by the fan 35. The gas-liquid two-phase refrigerant absorbs heat from the air through this heat exchange, and evaporates inside the evaporator 30, changing into low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant obtained by the evaporator 30 flows out to the compressor 10. The air whose heat has been absorbed by the gas refrigerant in the evaporator 30 is sent back into the room, thereby cooling the room.

[0027] The simulation device 1 includes a calculation device 2 , a memory 3 , a storage device 4 , an input device 5 , and a display 6 .

[0028] The arithmetic device 2 is a computing entity (computer) that executes various processes by executing various programs. The arithmetic device 2 may be configured, for example, as a microcontroller, a central processing unit (CPU), a micro processing unit (MPU), a tensor processing unit (TPU), or a graphics processing unit (GPU). The arithmetic device 2 has the function of executing various processes by executing programs, but some or all of these functions may be implemented using dedicated hardware circuits such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). The arithmetic device 2 is not limited to processors in the narrow sense that execute processes using stored programs, such as a CPU, MPU, TPU, or GPU, but may also include hardwired circuits such as an ASIC or FPGA. Furthermore, the arithmetic device 2 is not limited to von Neumann computers such as a CPU or GPU, but may also be configured as non-von Neumann computers such as a quantum computer or an optical computer. The arithmetic device 2 may also be interpreted as a processing circuit that executes predetermined processes. The computing device 2 may be configured as a single chip or multiple chips. Furthermore, the computing device 2 and related processing circuits may be configured as multiple computers interconnected by wire or wirelessly via a local area network or a wireless network. The computing device 2 and related processing circuits may be configured as a cloud computer that performs remote calculations based on input data and outputs the calculation results to other devices located at a distance.

[0029] The memory 3 includes a storage area (for example, a working area) that stores program code or work memory when the arithmetic unit 2 executes various programs. Examples of the memory 3 include volatile memories such as DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory), and non-volatile memories such as ROM (Read Only Memory) and flash memory.

[0030] The storage device 4 stores various programs and various data executed by the arithmetic device 2. The storage device 4 may be one or more non-transitory computer readable media, or one or more computer readable storage media. Examples of the storage device 4 include a hard disk drive (HDD) and a solid state drive (SSD).

[0031] The storage device 4 stores a simulation program 7 executed by the arithmetic device 2 and an allocation data table 8 used during the simulation. The arithmetic device 2 executes the simulation program 7 stored in the storage device 4 while referring to the allocation data table 8, thereby performing a simulation of the refrigeration cycle of the refrigerant flowing through the refrigerant circuit 101.

[0032] The input device 5 is an input interface such as a keyboard or a mouse (not shown) for receiving instructions from a user to the simulation device 1 .

[0033] The display 6 displays various images such as a simulation image for the user to perform a simulation of a refrigeration cycle.

[0034] 1, a calculation point on the path between the evaporator 30 and the compressor 10 is indicated by P1. A calculation point on the path between the compressor 10 and the condenser 20 is indicated by P2. A calculation point on the path between the condenser 20 and the expansion valve 40 is indicated by P3. A calculation point on the path between the expansion valve 40 and the evaporator 30 is indicated by P4.

[0035] The simulator 1 calculates steady-state values ​​indicating the steady state of the refrigerant at each of the calculation points P1 to P4 based on the initial values ​​using a predetermined calculation formula. Here, the steady-state values ​​include at least one of the pressure and specific enthalpy of the refrigerant at each of the calculation points P1 to P4 in the steady state. The initial values ​​include at least one of the pressure and specific enthalpy of the refrigerant at each of the calculation points P1 to P4 in the initial state.

[0036] For example, the simulation device 1 calculates the steady-state pressure (steady-state value) of the refrigerant at each of the calculation points P1 to P4 based on the initial-state pressure (initial value) of the refrigerant at each of the calculation points P1 to P4. The simulation device 1 also calculates the steady-state specific enthalpy (steady-state value) of the refrigerant at each of the calculation points P1 to P4 based on the initial-state specific enthalpy (initial value) of the refrigerant at each of the calculation points P1 to P4. Alternatively, the simulation device 1 calculates the steady-state pressure (steady-state value) and specific enthalpy (steady-state value) of the refrigerant at each of the calculation points P1 to P4 based on the initial-state pressure (initial value) and specific enthalpy (initial value) of the refrigerant at each of the calculation points P1 to P4.

[0037] As described above, the calculation of the steady-state values ​​of the refrigeration cycle requires initial values ​​for each calculation point P1 to P4. However, if the user manually sets the initial values ​​using the input device 5, the time required to set the initial values ​​may increase or an error may occur in setting the initial values. Furthermore, in the calculation of the steady-state values ​​of the refrigeration cycle, the closer the initial values ​​are to the solution, the better the convergence of the calculation. However, if an error occurs in setting the initial values, the convergence of the steady-state value calculation may deteriorate, increasing the time required to obtain a solution, or the calculation may diverge, resulting in an inability to obtain a solution. Therefore, the simulation device 1 is configured to prepare a Mollier diagram corresponding to the refrigerant circuit 101 in advance and associate each cycle point on the Mollier diagram with each calculation point in the refrigerant circuit 101, allowing the user to easily and accurately set the initial values ​​without manually entering the initial values.

[0038] [Mollier Diagram of Refrigerant Circuit] Figure 2 is a Mollier diagram used in a simulation of the refrigerant circuit 101 according to Embodiment 1. In Figure 2, a Mollier diagram corresponding to a pre-prepared refrigerant circuit 101 is shown in a graph with absolute pressure p on the vertical axis and specific enthalpy h on the horizontal axis. As shown in Figure 2, the Mollier diagram includes multiple cycle points C1 to C4. The multiple cycle points C1 to C4 correspond to calculation points P1 to P4 of the refrigerant circuit 101 in Figure 1, respectively.

[0039] In the Mollier diagram, the change in the graph from cycle point C1 to cycle point C2 indicates the change in the refrigerant when it passes through the compressor 10. The change in the graph from cycle point C2 to cycle point C3 indicates the change in the refrigerant when it passes through the condenser 20. The change in the graph from cycle point C3 to cycle point C4 indicates the change in the refrigerant when it passes through the expansion valve 40. The change in the graph from cycle point C4 to cycle point C1 indicates the change in the refrigerant when it passes through the evaporator 30.

[0040] The simulation device 1 prepares in advance different Mollier diagrams depending on the type of refrigerant circuit 101, and stores allocation values ​​previously assigned to each cycle point set in the Mollier diagram in an allocation data table 8, which is then stored in the storage device 4. Here, the allocation values ​​include at least one of the pressure and specific enthalpy of the refrigerant at each cycle point.

[0041] For example, FIG. 3 is a diagram illustrating an allocation data table 8 for the refrigerant circuit 101 stored in the simulation apparatus 1 according to the first embodiment. As shown in FIG. 3, the simulation apparatus 1 prepares in advance the Mollier diagram shown in FIG. 2 as a Mollier diagram corresponding to the refrigerant circuit 101 shown in FIG. 1, and stores in the allocation data table 8 pressures (allocation values) and specific enthalpies (allocation values) pre-allocated to each of the cycle points C1 to C4. Furthermore, the simulation apparatus 1 pre-allocates different allocation values ​​to each of the cycle points C1 to C4 depending on the type of refrigerant, and stores the allocation values ​​in the allocation data table 8. Note that in the example of FIG. 3, three types of refrigerant are illustrated: R32, R410A, and R290. However, the refrigerants are not limited to these types, and the user can set allocation values ​​for other types of refrigerants.

[0042] [Association between refrigerant circuit and Mollier diagram] The simulation device 1 associates one of a plurality of cycle points C1 to C4 in a Mollier diagram prepared in advance with one of a plurality of calculation points P1 to P4 in the refrigerant circuit 101. Specifically, the simulation device 1 associates each of a plurality of cycle points C1 to C4 in the Mollier diagram prepared in advance with a plurality of calculation points P1 to P4 in the refrigerant circuit 101, based on a command from the user using the input device 5.

[0043] For example, Fig. 4 is a diagram illustrating an example of the correspondence between calculation points P1 to P4 of the refrigerant circuit 101 and cycle points C1 to C4 of the Mollier diagram according to Embodiment 1. As shown in Fig. 4, the user associates the multiple cycle points C1 to C4 with the multiple calculation points P1 to P4 by linking the multiple calculation points P1 to P4 of the refrigerant circuit 101 displayed on the display 6 with the multiple cycle points C1 to C4 of the Mollier diagram displayed on the display 6 using lines or the like.

[0044] The user's association of calculation points with cycle points may be performed by other methods as well as the method shown in Fig. 4. For example, the user may associate the cycle points C1 to C4 with the calculation points P1 to P4 by inputting identifiers (e.g., C1 to C4) of the cycle points C1 to C4 in the Mollier diagram into input fields for the calculation points P1 to P4 in the refrigerant circuit 101 displayed on the display 6.

[0045] The simulation device 1 associates each of the multiple cycle points C1 to C4 in the Mollier diagram with each of the multiple calculation points P1 to P4 in the refrigerant circuit 101, and then acquires an assigned value at each cycle point as an initial value at that calculation point. Specifically, the simulation device 1 acquires an assigned value previously assigned to each of the multiple cycle points C1 to C4 as an initial value indicating the initial state of the refrigerant at the multiple calculation points P1 to P4 used in the simulation.

[0046] Here, the assigned value includes at least one of the pressure and the specific enthalpy of the refrigerant at each cycle point.

[0047] For example, the simulation device 1 acquires the pressures (assigned values) assigned to the cycle points C1 to C4 as the pressures (initial values) of the refrigerant in the initial state at the calculation points P1 to P4 from the assignment data table 8. The simulation device 1 also acquires the specific enthalpy (assigned values) assigned to the cycle points C1 to C4 as the specific enthalpy (initial values) of the refrigerant in the initial state at the calculation points P1 to P4 from the assignment data table 8. Alternatively, the simulation device 1 acquires the pressures (assigned values) and specific enthalpy (assigned values) assigned to the cycle points C1 to C4 as the pressures (initial values) and specific enthalpy (initial values) of the refrigerant in the initial state at the calculation points P1 to P4 from the assignment data table 8.

[0048] The simulation device 1 uses the allocation values ​​of each cycle point C1 to C4 obtained from the allocation data table 8 as described above as the initial values ​​of each calculation point P1 to P4, and calculates the steady-state values ​​of each calculation point P1 to P4 through simulation.

[0049] In this way, the simulation device 1 associates each of the calculation points P1 to P4 in the refrigerant circuit 101 with each of the cycle points C1 to C4 in the Mollier diagram prepared in advance, and uses the assigned values ​​previously assigned to each of the cycle points C1 to C4 as the initial values ​​at each of the calculation points P1 to P4 used in the simulation. This eliminates the need for the user to manually input the initial values ​​at each of the calculation points P1 to P4 used in the simulation using the input device 5, thereby avoiding an increase in the time required to set the initial values ​​and the occurrence of errors in setting the initial values, and making it possible to properly perform a simulation of the refrigeration cycle in a short time.

[0050] [Examples of Other Refrigerant Circuits] The simulation device 1 can apply the assigned values ​​of each cycle point in a Mollier diagram prepared in advance to the initial values ​​of each calculation point in other refrigerant circuits, not limited to the refrigerant circuit 101 shown in FIG. 1 described above.

[0051] Fig. 5 is a diagram showing the configuration of another refrigerant circuit 102 according to Embodiment 1. Note that, with regard to the refrigerant circuit 102 in Fig. 5, only the configuration that differs from the refrigerant circuit 101 in Fig. 1 will be described.

[0052] As shown in FIG. 5, the refrigerant circuit 102 further includes a condenser 20A, a fan 25A, and an expansion valve 40A.

[0053] Condenser 20A is a heat exchanger configured to exchange heat between the refrigerant and outdoor air drawn in by fan 25A. Fan 25A is configured to operate and stop under the control of a control device, and the amount of air sent to condenser 20A is changed by changing the number of rotations per unit time, i.e., the rotational speed. Expansion valve 40A reduces the pressure of the refrigerant that has flowed in under the control of the control device, and allows the refrigerant obtained by the reduced pressure to flow out. Expansion valve 40 can adjust the flow rate of the refrigerant and the amount of pressure reduction by adjusting its opening under the control of the control device.

[0054] The discharge port 12 of the compressor 10 is connected to one end of the condenser 20 via pipes 81 and 82. The other end of the condenser 20 is connected to one end of the expansion valve 40 via pipes 83 and 84. The other end of the expansion valve 40 is connected to one end of the condenser 20A via pipes 85 and 86. The other end of the condenser 20A is connected to one end of the expansion valve 40A via pipes 87 and 88. The other end of the expansion valve 40A is connected to one end of the evaporator 30 via pipes 89 and 90. The other end of the evaporator 30 is connected to the suction port 11 of the compressor 10 via pipes 91 and 92.

[0055] In the refrigerant circuit 102 configured as described above, the refrigerant flows in the following order: compressor 10, condenser 20, expansion valve 40, condenser 20A, expansion valve 40A, and evaporator 30. Such a refrigerant circuit 102 can be applied to large commercial air conditioners.

[0056] As shown in Figure 5, a calculation point on the path between the evaporator 30 and the compressor 10 is indicated by P11. A calculation point on the path between the compressor 10 and the condenser 20 is indicated by P12. A calculation point on the path between the condenser 20 and the expansion valve 40 is indicated by P13. A calculation point on the path between the expansion valve 40 and the condenser 20A is indicated by P14. A calculation point on the path between the condenser 20A and the expansion valve 40A is indicated by P15. A calculation point on the path between the expansion valve 40A and the evaporator 30 is indicated by P16.

[0057] The simulator 1 calculates steady-state values ​​indicating the steady state of the refrigerant at each of the calculation points P11 to P16 based on the initial values ​​using a predetermined calculation formula. Here, the steady-state values ​​include at least one of the pressure and specific enthalpy of the refrigerant at each of the calculation points P11 to P16 in the steady state. The initial values ​​include at least one of the pressure and specific enthalpy of the refrigerant at each of the calculation points P11 to P16 in the initial state.

[0058] Fig. 6 is a Mollier diagram used in a simulation of another refrigerant circuit 102 according to the first embodiment. In Fig. 6, a Mollier diagram corresponding to a pre-prepared refrigerant circuit 102 is shown in a graph with absolute pressure p on the vertical axis and specific enthalpy h on the horizontal axis. As shown in Fig. 6, the Mollier diagram includes multiple cycle points C11 to C16. The multiple cycle points C11 to C16 correspond to calculation points P11 to P16 of the refrigerant circuit 102 in Fig. 5, respectively.

[0059] In the Mollier diagram, the change in the graph from cycle point C11 to cycle point C12 shows the change in the refrigerant when it passes through the compressor 10. The change in the graph from cycle point C12 to cycle point C13 shows the change in the refrigerant when it passes through the condenser 20. The change in the graph from cycle point C13 to cycle point C14 shows the change in the refrigerant when it passes through the expansion valve 40. The change in the graph from cycle point C14 to cycle point C15 shows the change in the refrigerant when it passes through the condenser 20A. The change in the graph from cycle point C15 to cycle point C16 shows the change in the refrigerant when it passes through the expansion valve 40A. The change in the graph from cycle point C16 to cycle point C11 shows the change in the refrigerant when it passes through the evaporator 30.

[0060] Fig. 7 is a diagram illustrating an allocation data table 8 related to another refrigerant circuit 102 stored in the simulation apparatus 1 according to the first embodiment. As shown in Fig. 7, the simulation apparatus 1 prepares in advance the Mollier diagram shown in Fig. 6 as a Mollier diagram corresponding to the refrigerant circuit 102 shown in Fig. 5, and stores allocation values ​​(pressure, specific enthalpy) previously assigned to each of the cycle points C11 to C16 in the allocation data table 8. Furthermore, the simulation apparatus 1 pre-assigns allocation values ​​that differ depending on the type of refrigerant (R32, R410A, R290) to each of the cycle points C11 to C16 and stores the allocation data table 8.

[0061] Based on a command from the user via the input device 5, the simulation device 1 associates a plurality of calculation points P11 to P16 in the refrigerant circuit 102 with a plurality of cycle points C1 to C16 in a Mollier diagram prepared in advance.

[0062] For example, Fig. 8 is a diagram illustrating the correspondence between calculation points P11 to P16 of another refrigerant circuit 102 according to the first embodiment and cycle points C1 to C16 of the Mollier diagram. As shown in Fig. 8, the user associates the calculation points P11 to P16 with the cycle points C11 to C16 of the refrigerant circuit 102 displayed on the display 6 by connecting the calculation points P11 to P16 of the refrigerant circuit 102 displayed on the display 6 with the cycle points C11 to C16 of the Mollier diagram shown in Fig. 6 displayed on the display 6 using a connecting line or the like. Note that the user may also associate the calculation points P11 to P16 with the cycle points C11 to C16 of the Mollier diagram by inputting identifiers (e.g., C11 to C16) of the cycle points C11 to C16 of the refrigerant circuit 101 displayed on the display 6 in input fields for the calculation points P11 to P16 of the refrigerant circuit 101.

[0063] The simulation device 1 associates each of the multiple cycle points C11 to C16 in the Mollier diagram with a multiple calculation point P11 to P16 in the refrigerant circuit 102, and then obtains from the allocation data table 8 allocation values ​​(pressure, specific enthalpy) that have been previously assigned to each of the multiple cycle points C1 to C16 as initial values ​​(pressure, specific enthalpy) that indicate the initial state of the refrigerant at the multiple calculation points P11 to P16 used in the simulation.

[0064] The simulation device 1 uses the allocation values ​​of each cycle point C11 to C16 obtained from the allocation data table 8 as described above as the initial values ​​of each calculation point P11 to P16, and calculates the steady-state values ​​of each calculation point P11 to P16 through simulation.

[0065] In this way, the simulation device 1 associates each of the cycle points C11 to C16 in the Mollier diagram prepared in advance with each of the calculation points P11 to P16 in the refrigerant circuit 101, and can use the assigned values ​​previously assigned to each of the cycle points C11 to C16 as the initial values ​​for each of the calculation points P11 to P16 used in the simulation. This eliminates the need for the user to manually input the initial values ​​for each of the calculation points P11 to P16 used in the simulation using the input device 5, thereby avoiding an increase in the time required to set the initial values ​​and the occurrence of errors in setting the initial values, and making it possible to properly perform a simulation of the refrigeration cycle in a short time.

[0066] Furthermore, by preparing in advance different Mollier diagrams depending on the type of refrigerant circuit, such as the refrigerant circuit 101 shown in FIG. 1 or the refrigerant circuit 102 shown in FIG. 5, the simulation device 1 can easily obtain the assigned values ​​of cycle points in the Mollier diagram as the initial values ​​of calculation points in various types of refrigerant circuits.

[0067] In addition, the user may prepare a Mollier diagram in advance for other types of refrigerant circuits, not limited to the refrigerant circuit 101 in Figure 1 and the refrigerant circuit 102 in Figure 5, and use the Mollier diagram to set the allocation value as the initial value of each calculation point.

[0068] [Variations of Correspondence Between Refrigerant Circuits and Mollier Diagrams] In the examples of Figures 4 and 8 described above, the simulation device 1 associates one of the multiple cycle points with one of the multiple calculation points. However, this is not limited to such a process, and one of the multiple cycle points may be associated with two or more of the multiple calculation points. Furthermore, in the examples of Figures 4 and 8, the simulation device 1 acquires an assigned value at one cycle point as the initial value at one calculation point. However, this is not limited to such a process, and one of the multiple cycle points may be associated with an assigned value at one cycle point as the initial value at each of two or more calculation points. In other words, the number of calculation points in the refrigerant circuit does not necessarily have to match the number of cycle points in the Mollier diagram.

[0069] 9 is a diagram for explaining a modified example of the correspondence between each calculation point of the refrigerant circuit 101 and each cycle point of the Mollier diagram according to Embodiment 1. Note that in Fig. 9, only the parts that are different from the correspondence in Fig. 4 will be explained.

[0070] 9 , the refrigerant circuit 101 further includes an accumulator 63. The accumulator 63 is provided between the evaporator 30 and the compressor 10, and is a container that temporarily stores the refrigerant flowing out from the evaporator 30. The accumulator 63 and the evaporator 30 are connected via a pipe 77. The accumulator 63 and the suction port 11 of the compressor 10 are connected via a pipe 78.

[0071] A calculation point on the path between the accumulator 63 and the compressor 10 is indicated by P1a. A calculation point on the path between the accumulator 63 and the pipe 77 is indicated by P1b. A calculation point on the path between the evaporator 30 and the pipe 77 is indicated by P1c. A calculation point on the path between the pipe 71 and the pipe 72 is indicated by P2a. A calculation point on the path between the condenser 20 and the pipe 72 is indicated by P2b. The three calculation points P1a, P1b, and P1c are included in the calculation point group P1. The two calculation points P2a and P2b are included in the calculation point group P2.

[0072] 9 , the group of calculation points P1 includes three calculation points P1a, P1b, and P1c, and the refrigerant state (pressure, specific enthalpy) at each of the calculation points P1a, P1b, and P1c is the same or approximately the same. Therefore, the simulation device 1 groups the three calculation points P1a, P1b, and P1c into the group of calculation points P1 and associates a cycle point C1 on a Mollier diagram prepared in advance with the group of calculation points P1. The simulation device 1 acquires assigned values ​​at the cycle point C1 as initial values ​​at the three calculation points P1a, P1b, and P1c, and calculates steady-state values ​​at each of the calculation points P1a, P1b, and P1c using the assigned values.

[0073] Similarly, the group of calculation points P2 includes two calculation points P2a and P2b, but the refrigerant state (pressure, specific enthalpy) at each of the calculation points P2a and P2b is the same or approximately the same. Therefore, the simulation device 1 groups the two calculation points P2a and P2b together as the group of calculation points P2 and associates the group of calculation points P2 with a cycle point C2 on a Mollier diagram prepared in advance. The simulation device 1 obtains an assigned value at the cycle point C2 as the initial value at the two calculation points P2a and P2b, and calculates steady-state values ​​at each of the calculation points P2a and P2b using the assigned value.

[0074] In this way, the user can associate cycle points in the Mollier diagram with calculation points at any location in the refrigerant circuit 101. Furthermore, the user can associate cycle points in the Mollier diagram with any number of calculation points in the refrigerant circuit 101.

[0075] 10 to 14, a simulation device 1 according to a second embodiment will be described. As described in the first embodiment, the simulation device 1 can acquire initial values ​​(pressure, specific enthalpy) indicating the initial state of the refrigerant at at least one calculation point in the refrigerant circuits 101 and 102.

[0076] Here, in order to calculate, by simulation, steady-state values ​​indicating the steady state of the refrigerant in the refrigerant circuits 101, 102, the user needs to input relevant values ​​relating to various configurations in the initial state into the simulation device 1. The relevant values ​​include at least one of the initial flow rate of the refrigerant flowing through the refrigerant circuits 101, 102, the initial opening degree of the expansion valve 40, the initial air flow rate of the fan 25, a correction value for the heat transfer coefficient in the condenser 20, and the initial amount of refrigerant sealed in the refrigerant circuits 101, 102.

[0077] As described above, calculation of steady-state values ​​of the refrigeration cycle requires related values ​​for various components in the initial state. However, if the user manually sets the related values ​​using the input device 5, the time required to set the related values ​​may increase or an error may occur in setting the related values. Furthermore, in calculation of steady-state values ​​of the refrigeration cycle, the closer the related values ​​are to the solution, the better the convergence of the calculation. However, if an error occurs in setting the related values, the convergence of the steady-state value calculation may deteriorate, increasing the time required to obtain a solution or the calculation may diverge, making it impossible to obtain a solution. Therefore, the simulation device 1 is configured to calculate related values ​​for various components in the initial state based on the initial values ​​(pressure, specific enthalpy) of the refrigerant at each calculation point obtained by the method of embodiment 1.

[0078] [Configuration of Refrigerant Circuit] Fig. 10 is a diagram showing the configuration of a refrigerant circuit 103 according to embodiment 2. Note that, with regard to the refrigerant circuit 103 in Fig. 11, only the configuration that differs from the refrigerant circuit 102 in Fig. 5 will be described.

[0079] As shown in Fig. 10, the refrigerant circuit 103 further includes a capillary tube 65 for decompressing the refrigerant. The compressor 10 and the condenser 20 are connected via pipes 71, 72A, and 72B. The evaporator 30 and one end of the accumulator 63 are connected via pipes 77A and 77B. The other end of the accumulator 63 and the compressor 10 are connected via pipes 77C and 78. One end of the capillary tube 65 is connected to pipe 72C, which is connected to the branch point between pipes 72A and 72B. The other end of the capillary tube 65 is connected to pipe 72D, which is connected to the branch point between pipes 77A and 77B.

[0080] The calculation point of the branch point between pipes 72A and 72B is indicated by P5. The calculation point on the path between pipe 72B and condenser 20 is indicated by P6. The calculation point on the path between evaporator 30 and pipe 77A is indicated by P7. The calculation point of the branch point between pipes 72A and 72B is indicated by P8.

[0081] In the refrigerant circuit 103 configured as described above, the refrigerant discharged from the compressor 10 at a flow rate of 1 is divided into refrigerant at a flow rate of 2 and refrigerant at a flow rate of 3. The refrigerant at flow rate 2 flows to the accumulator 63 via the pipe 72C, the capillary tube 65, and the pipe 72D. The refrigerant at flow rate 3 flows to the condenser 20 via the pipe 72B. The flow rates 2 and 3 combined form a flow rate of 1.

[0082] [Calculation of Initial Flow Rate of Refrigerant] The simulation device 1 can calculate the flow rate 1 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103 as a related value related to the refrigerant circuit 103 in the initial state, using the following equation (1).

[0083] In equation (1), Gr1 is the flow rate 1 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103. Vst is the stroke volume (volume) of the compressor 10. ρin is the suction density of the compressor 10. F is the frequency of the compressor 10. ηv is the volumetric efficiency of the compressor 10. Vst, ρin, F, and ηv are fixed values ​​and are pre-stored in the storage device 4 of the simulation device 1. ρin can be calculated by the simulation device 1 based on the initial values ​​(pressure, specific enthalpy) at the calculation point group P1 (suction side calculation point). The initial values ​​(pressure, specific enthalpy) at the calculation point group P1 (suction side calculation point) can be calculated by the simulation device 1 using the method of embodiment 1.

[0084] Furthermore, the simulation device 1 can calculate a flow rate 2 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103 using the following equation (2).

[0085] In equation (2), Gr2 is the flow rate 2 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103. f2 is the flow rate ratio of flow rate 2 to flow rate 1.

[0086] Furthermore, the simulation device 1 can calculate a flow rate 3 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103 using the following equation (3).

[0087] In equation (3), Gr3 is flow rate 3 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103. f3 is the flow rate ratio of flow rate 3 to flow rate 1.

[0088] The simulation apparatus 1 associates a second flow rate ratio (f2) corresponding to flow rate 2 with the path passing through pipe 72C, capillary tube 65, and pipe 72D, and stores the association in the storage device 4. The simulation apparatus 1 also associates a third flow rate ratio (f3) corresponding to flow rate 3 with the path passing through pipe 72B, and stores the association in the storage device 4. Furthermore, the simulation apparatus 1 stores identifiers 1 to 3 corresponding to flow rates 1 to 3, respectively, in the storage device 4.

[0089] When a user wishes to calculate flow rate 1, the user simply uses the input device 5 to select identifier 1 from among the multiple identifiers, and in this case, the simulation device 1 calculates flow rate 1 based on formula (1). When a user wishes to calculate flow rate 2, the user simply uses the input device 5 to select identifier 2 from among the multiple identifiers, and in this case, the simulation device 1 calculates flow rate 2 based on formula (2). When a user wishes to calculate flow rate 3, the user simply uses the input device 5 to select identifier 3 from among the multiple identifiers, and in this case, the simulation device 1 calculates flow rate 3 based on formula (3).

[0090] In this way, the simulation device 1 can back-calculate the flow rates 1 to 3 (initial flow rates) flowing through the refrigerant circuit 103 from the initial values ​​(pressure, specific enthalpy) of the calculation point group P1 (suction-side calculation point). Furthermore, the simulation device 1 can calculate specific flow rates (flow rates 1 to 3) of the refrigerant flowing through a specific path based on an identifier selected by the user. This eliminates the need for the user to manually input the flow rates 1 to 3 (initial flow rates) flowing through the refrigerant circuit 103 using the input device 5 in order to calculate steady-state values ​​indicating the steady state of the refrigerant through a simulation. This avoids an increase in the time required to set the flow rates 1 to 3 (initial flow rates) and the occurrence of errors in setting the flow rates 1 to 3 (initial flow rates), thereby enabling the refrigeration cycle simulation to be properly performed in a short time.

[0091] [Calculation of Initial Opening Degree of Expansion Valve] FIG. 11 is a diagram for explaining an example of calculation of the initial opening degree of the expansion valve 40 in the refrigerant circuit 103 according to the second embodiment.

[0092] The simulation device 1 can calculate the initial opening degree of the expansion valve 40 as a related value related to the expansion valve 40 in the initial state using the following equation (4).

[0093] In equation (4), Pulse is the initial opening of the expansion valve 40. Pin is the initial value of the pressure at calculation point P3 (inlet side calculation point) located on the inlet side of the expansion valve 40. Hin is the initial value of the specific enthalpy at calculation point P3 (inlet side calculation point) located on the inlet side of the expansion valve 40. Pout is the initial value of the pressure at calculation point P4 (outlet side calculation point) located on the outlet side of the expansion valve 40. Gr is the flow rate 3 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103. Pin, hin, and Pout can be calculated by the simulation device 1 using the method of embodiment 1. Gr can be calculated by the simulation device 1 using the above-mentioned equation (3).

[0094] In this way, the simulation device 1 can back-calculate the initial opening of the expansion valve 40 from the initial values ​​(pressure, specific enthalpy) at calculation point P3 (inlet-side calculation point) and the initial value (pressure) at calculation point P4 (outlet-side calculation point). This eliminates the need for the user to manually input the initial opening of the expansion valve 40 using the input device 5 in order to calculate a steady-state value indicating the steady state of the refrigerant through simulation. This avoids an increase in the time required to set the initial opening of the expansion valve 40 and the occurrence of an error in setting the initial opening of the expansion valve 40, making it possible to properly perform a simulation of the refrigeration cycle in a short time.

[0095] [Calculation of Initial Opening Degree of Expansion Valve] FIG. 12 is a diagram for explaining an example of calculation of a correction value for the initial air flow rate of the fan 25 or the heat transfer coefficient in the condenser 20 in the refrigerant circuit 103 according to the second embodiment.

[0096] The simulation device 1 can calculate the initial airflow rate of the fan 25 as a related value related to the fan 25 in the initial state using the following equation (5).

[0097] In equation (5), Vair is the initial air volume of the fan 25. Pin is the initial value of the pressure at calculation point P6 (inlet side calculation point) located on the inlet side of the condenser 20. Hin is the initial value of the specific enthalpy at calculation point P6 (inlet side calculation point) located on the inlet side of the condenser 20. Hout is the initial value of the specific enthalpy at calculation point P3 (outlet side calculation point) located on the outlet side of the condenser 20. Gr is the flow rate 3 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103. Pin, hin, and Pout can be calculated by the simulation device 1 using the method of embodiment 1. Gr can be calculated by the simulation device 1 using the above-mentioned equation (3).

[0098] In this way, the simulation device 1 can back-calculate the initial air volume of the fan 25 from the initial values ​​(pressure, specific enthalpy) at calculation point P6 (inlet-side calculation point) and the initial value (specific enthalpy) at calculation point P3 (outlet-side calculation point). This eliminates the need for the user to manually input the initial air volume of the fan 25 using the input device 5 in order to calculate a steady-state value indicating the steady state of the refrigerant through simulation. This avoids an increase in the time required to set the initial air volume of the fan 25 and an error in setting the initial air volume of the fan 25, and allows the refrigeration cycle simulation to be properly performed in a short time.

[0099] The simulation device 1 can calculate the correction value of the heat transfer coefficient in the condenser 20 as the related value related to the condenser 20 in the initial state using the following equation (6).

[0100] In equation (6), η is a correction value for the heat transfer coefficient in the condenser 20. Pin is the initial value of the pressure at calculation point P6 (inlet side calculation point) located on the inlet side of the condenser 20. Hin is the initial value of the specific enthalpy at calculation point P6 (inlet side calculation point) located on the inlet side of the condenser 20. Hout is the initial value of the specific enthalpy at calculation point P3 (outlet side calculation point) located on the outlet side of the condenser 20. Gr is the flow rate 3 (initial flow rate) of the refrigerant flowing through the refrigerant circuit 103. Pin, hin, and Pout can be calculated by the simulation device 1 using the method of embodiment 1. Gr can be calculated by the simulation device 1 using the above-mentioned equation (3).

[0101] In this way, the simulation device 1 can back-calculate the correction value of the heat transfer coefficient in the condenser 20 from the initial values ​​(pressure, specific enthalpy) at calculation point P6 (inlet-side calculation point) and the initial value (specific enthalpy) at calculation point P3 (outlet-side calculation point). This eliminates the need for the user to manually input the correction value of the heat transfer coefficient in the condenser 20 using the input device 5 in order to calculate a steady-state value indicating the steady state of the refrigerant through simulation. This avoids an increase in the time required to set the correction value of the heat transfer coefficient in the condenser 20 and an error in setting the correction value of the heat transfer coefficient in the condenser 20, and allows the refrigeration cycle simulation to be properly performed in a short time.

[0102] [Calculation of Initial Charge Amount] FIG. 13 is a diagram for explaining an example of calculation of the initial charge amount of refrigerant in the refrigerant circuit 103 according to the second embodiment.

[0103] The simulation device 1 can calculate the initial amount of refrigerant charged into the refrigerant circuit 103 in the initial state as a related value related to the refrigerant circuit 103 in the initial state using the following equation (7).

[0104] In equation (7), ΣM is the sum of the initial amounts of refrigerant charged in each component of the refrigerant circuit 103. For example, the initial amount f1 of refrigerant charged in the pipe 72A can be calculated by the simulation device 1 based on the initial value P in of the pressure at a calculation point P2 (inflow-side calculation point) located on the inflow side of the pipe 72A, the initial value h in of the specific enthalpy at the calculation point P2 (inflow-side calculation point), the initial value h out of the specific enthalpy at a calculation point P5 (outflow-side calculation point) located on the outflow side of the pipe 72A, and the flow rate 1 (initial flow rate) of the refrigerant flowing through the pipe 72A.

[0105] The initial filling amount f2 of pipe 72B can be calculated by simulation device 1 based on the initial value Pin of pressure at calculation point P5 (inlet side calculation point) located on the inlet side of pipe 72B, the initial value hin of specific enthalpy at calculation point P5 (inlet side calculation point), the initial value hout of specific enthalpy at calculation point P6 (outlet side calculation point) located on the outlet side of pipe 72B, and the flow rate 3 (initial flow rate) of the refrigerant flowing through pipe 72B.

[0106] The initial filling amount f3 of the condenser 20 can be calculated by the simulation device 1 based on the initial value Pin of the pressure at calculation point P6 (inlet side calculation point) located on the inlet side of the condenser 20, the initial value hin of the specific enthalpy at calculation point P6 (inlet side calculation point), the initial value hout of the specific enthalpy at calculation point P3 (outlet side calculation point) located on the outlet side of the condenser 20, and the flow rate 3 (initial flow rate) of the refrigerant flowing through the condenser 20.

[0107] The initial filling amount f4 of the evaporator 30 can be calculated by the simulation device 1 based on the initial value Pin of the pressure at calculation point P4 (inlet side calculation point) located on the inlet side of the evaporator 30, the initial value hin of the specific enthalpy at calculation point P4 (inlet side calculation point), the initial value hout of the specific enthalpy at calculation point P7 (outlet side calculation point) located on the outlet side of the evaporator 30, and the flow rate 3 (initial flow rate) of the refrigerant flowing through the evaporator 30.

[0108] The initial filling amount f5 of pipe 77A can be calculated by simulation device 1 based on the initial value Pin of pressure at calculation point P7 (inlet side calculation point) located on the inlet side of pipe 77A, the initial value hin of specific enthalpy at calculation point P7 (inlet side calculation point), the initial value hout of specific enthalpy at calculation point P8 (outlet side calculation point) located on the outlet side of pipe 77A, and the flow rate 3 (initial flow rate) of the refrigerant flowing through pipe 77A.

[0109] The initial filling amount f6 of the accumulator 63 can be calculated by the simulation device 1 based on the initial value Pin of the pressure at calculation point P8 (inlet side calculation point) located on the inlet side of the accumulator 63, the initial value hin of the specific enthalpy at calculation point P8 (inlet side calculation point), the initial value hout of the specific enthalpy at calculation point group P1 (outlet side calculation point) located on the outlet side of the accumulator 63, and the flow rate 1 (initial flow rate) of the refrigerant flowing through the accumulator 63.

[0110] As described above, the simulation device 1 calculates the initial refrigerant amounts f1 to f6 in each configuration, and calculates the total value of the initial amounts in the refrigerant circuit 103 by adding up these initial amounts f1 to f6.

[0111] In this way, the simulation device 1 can back-calculate the initial charging amount in the refrigerant circuit 103 from the initial values ​​(pressure, specific enthalpy) at each of the multiple inlet-side calculation points located on the inlet side of each of the multiple configurations and the initial values ​​(specific enthalpy) at each of the multiple outlet-side calculation points located on the outlet side of each of the multiple configurations. This eliminates the need for the user to manually input the initial charging amount using the input device 5 in order to calculate a steady-state value indicating the steady state of the refrigerant through simulation. This avoids an increase in the time required to set the initial charging amount and the occurrence of an error in setting the initial charging amount, making it possible to properly perform a simulation of the refrigeration cycle in a short time.

[0112] [Processing of Simulation Apparatus] Fig. 14 is a flowchart relating to processing executed by the simulation apparatus 1 according to embodiment 2. The arithmetic unit 2 of the simulation apparatus 1 executes the simulation program 7 to execute the processing of the flowchart shown in Fig. 14. In Fig. 14, "S" is used as an abbreviation for "STEP."

[0113] 14 , the simulation apparatus 1 determines whether or not a command to associate the refrigerant circuit 102 with the Mollier diagram has been received from the user using the input device 5 (S1). If the simulation apparatus 1 has not received a command to associate the refrigerant circuit 102 with the Mollier diagram from the user (NO in S1), the simulation apparatus 1 terminates this process. On the other hand, if the simulation apparatus 1 has received a command to associate the refrigerant circuit 102 with each cycle point of the Mollier diagram of the refrigerant circuit 102 that has been stored in advance in the storage device 4 (S2).

[0114] The simulation device 1 determines whether or not a command to acquire initial values ​​(pressure, specific enthalpy) at each calculation point has been received from the user using the input device 5 (S3). If the command to acquire initial values ​​has not been received (NO in S3), the simulation device 1 terminates this processing. On the other hand, if the command to acquire initial values ​​has been received (YES in S3), the simulation device 1 acquires, as initial values, the assigned values ​​(pressure, specific enthalpy) assigned to the cycle points on the Mollier diagram (S4).

[0115] The simulation device 1 determines whether or not a command to calculate the initial flow rate of refrigerant flowing through the refrigerant circuit 103 has been received from the user using the input device 5 (S5). If the command to calculate the initial flow rate has not been received (NO in S5), the simulation device 1 ends this process. On the other hand, if the command to calculate the initial flow rate has been received (YES in S5), the simulation device 1 calculates the initial flow rate based on the initial value acquired in S4 using equations (1) to (3) (S6).

[0116] The simulation device 1 determines whether or not a command to calculate the initial opening degree of the expansion valve 40 has been received from the user using the input device 5 (S7). If the simulation device 1 has not received a command to calculate the initial opening degree of the expansion valve 40 (NO in S7), the simulation device 1 ends this processing. On the other hand, if the simulation device 1 has received a command to calculate the initial opening degree of the expansion valve 40 (YES in S7), the simulation device 1 calculates the initial opening degree of the expansion valve 40 based on the initial value acquired in S4 using equation (4) (S8).

[0117] The simulation device 1 determines whether or not a command to calculate a heat exchanger initial value (for example, an initial airflow rate of the fan 25 or a correction value for the heat transfer coefficient in the condenser 20) has been received from the user using the input device 5 (S9). If the command to calculate the heat exchanger initial value has not been received (NO in S9), the simulation device 1 ends this process. On the other hand, if the command to calculate the heat exchanger initial value has been received (YES in S9), the simulation device 1 calculates the initial airflow rate of the fan 25 based on the initial value acquired in S4 using equation (5), or calculates the correction value for the heat transfer coefficient in the condenser 20 based on the initial value acquired in S4 using equation (6) (S10).

[0118] The simulation device 1 determines whether or not a command to calculate the initial amount of refrigerant charged in the refrigerant circuit 103 has been received from the user using the input device 5 (S11). If the simulation device 1 has not received a command to calculate the initial amount of refrigerant charged (NO in S11), the simulation device 1 terminates this process. On the other hand, if the simulation device 1 has received a command to calculate the initial amount of refrigerant charged (YES in S11), the simulation device 1 calculates the initial amount of refrigerant charged based on the initial value acquired in S4 using equation (7) (S12). Thereafter, the simulation device 1 terminates this process.

[0119] As described above, the simulation device 1 associates multiple cycle points in a Mollier diagram prepared in advance with multiple calculation points in the refrigerant circuit 102, and can use the assigned values ​​previously assigned to each of the multiple cycle points as initial values ​​indicating the initial state of the refrigerant at each of the multiple calculation points used in the simulation. This eliminates the need for the user to manually input the initial values ​​of each calculation point used in the simulation, thereby avoiding an increase in the time required to set the initial values ​​and the occurrence of errors in setting the initial values, and making it possible to properly perform a simulation of the refrigeration cycle in a short time.

[0120] Furthermore, the simulation device 1 can calculate related values ​​for at least one configuration included in the refrigerant circuit 102 from the initial values ​​(pressure, specific enthalpy) of the calculation points obtained using the Mollier diagram. This eliminates the need for the user to manually input related values ​​to be used in the simulation, thereby avoiding an increase in the time required to set the related values ​​and the occurrence of errors in setting the related values, and making it possible to properly perform a simulation of the refrigeration cycle in a short time.

[0121] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0122] 1 Simulation device, 2 Arithmetic unit, 3 Memory, 4 Storage device, 5 Input device, 6 Display, 7 Simulation program, 8 Allocation data table, 10 Compressor, 11 Intake port, 12 Discharge port, 20, 20A Condenser, 25, 25A, 35 Fan, 30 Evaporator, 40, 40A Expansion valve, 63 Accumulator, 65 Capillary tube, 71, 72, 72A, 72B, 72C, 72D, 73, 74, 75, 76, 77, 77A, 77B, 77C, 78, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92 Piping, 100 Simulation system, 101, 102, 103 Refrigerant circuit.

Claims

1. A simulation device that executes a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit, comprising: a storage device; and a calculation device that executes the simulation in accordance with a simulation program stored in the storage device, wherein the calculation device obtains an initial value that indicates an initial state of the refrigerant at at least one calculation point in the refrigerant circuit, and calculates a related value for at least one configuration included in the refrigerant circuit based on the initial value.

2. The simulation device according to claim 1, wherein the initial values ​​include at least one of the pressure and specific enthalpy of the refrigerant.

3. A simulation device according to claim 1 or claim 2, wherein the at least one configuration includes a compressor, the at least one calculation point includes a suction side calculation point located on the suction side of the compressor, and the arithmetic device acquires a stroke volume of the compressor, a frequency of the compressor, a volumetric efficiency of the compressor, and the initial value at the suction side calculation point, and calculates an initial flow rate of the refrigerant to be used in the simulation as the related value based on the stroke volume, the frequency, the volumetric efficiency, and the initial value at the suction side calculation point.

4. The simulation device according to claim 3, wherein the calculation device calculates a specific flow rate of the refrigerant flowing through the specific path based on the flow rate ratio assigned to the specific path constituting the refrigerant circuit and the initial flow rate.

5. The simulation device described in claim 4, wherein the at least one configuration includes an expansion valve, the at least one calculation point includes an inlet calculation point located on the inlet side of the expansion valve and an outlet calculation point located on the outlet side of the expansion valve, and the calculation device acquires the initial value at the inlet calculation point, the initial value at the outlet calculation point, and the specific flow rate, and calculates an initial opening of the expansion valve to be used in the simulation as the related value based on the initial value at the inlet calculation point, the initial value at the outlet calculation point, and the specific flow rate.

6. The simulation device according to claim 4 or 5, wherein the at least one configuration includes a heat exchanger and a fan that supplies air to the heat exchanger, and the at least one calculation point includes an inlet calculation point located on the inlet side of the heat exchanger and an outlet calculation point located on the outlet side of the heat exchanger, and the calculation device acquires the initial value at the inlet calculation point, the initial value at the outlet calculation point, and the specific flow rate, and calculates, as the related value, an initial air volume of the fan used in the simulation or a correction value of the heat transfer coefficient in the heat exchanger based on the initial value at the inlet calculation point, the initial value at the outlet calculation point, and the specific flow rate.

7. The simulation device according to any one of claims 4 to 6, wherein the at least one configuration includes a plurality of configurations each including the compressor, an expansion valve, and a heat exchanger, and the at least one calculation point includes a plurality of inlet calculation points located on the inlet side of each of the plurality of configurations and a plurality of outlet calculation points located on the outlet side of each of the plurality of configurations, and the arithmetic device acquires the initial value at each of the plurality of inlet calculation points, the initial value at each of the plurality of outlet calculation points, and the specific flow rate of the refrigerant flowing through each of the plurality of configurations, and calculates, as the related value, an initial amount of refrigerant sealed in the refrigerant circuit used in the simulation based on the initial value at each of the plurality of inlet calculation points, the initial value at each of the plurality of outlet calculation points, and the specific flow rate of the refrigerant flowing through each of the plurality of configurations.

8. A simulation device according to any one of claims 1 to 7, wherein the calculation device associates a plurality of cycle points in a Mollier diagram prepared in advance with a plurality of calculation points in the refrigerant circuit, and obtains, as the initial value, an assigned value that is assigned in advance to at least one cycle point that corresponds to the at least one calculation point among the plurality of cycle points.

9. The simulation device according to claim 8, wherein different Mollier diagrams are prepared in advance according to the type of the refrigerant circuit.

10. A simulation device according to claim 8 or claim 9, wherein the allocation value, which differs depending on the type of refrigerant, is assigned in advance to each of the plurality of cycle points.

11. A simulation method for simulating a refrigeration cycle of a refrigerant flowing through a refrigerant circuit, the simulation method including, as processing executed by a computer, a step of acquiring an initial value indicating an initial state of the refrigerant at at least one calculation point in the refrigerant circuit, and a step of calculating a related value for at least one configuration included in the refrigerant circuit based on the initial value.

12. A simulation program that executes a simulation of a refrigeration cycle of a refrigerant flowing through a refrigerant circuit, the simulation program causing a computer to execute the steps of: acquiring an initial value indicating an initial state of the refrigerant at at least one calculation point in the refrigerant circuit; and calculating a related value for at least one configuration included in the refrigerant circuit based on the initial value.

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