Refrigeration cycle device, and refrigeration cycle system

Abstract

To provide a refrigeration cycle device making determination of a refrigerant amount easy to be appropriately performed.SOLUTION: A refrigeration cycle device includes: a compressor; a heat source side heat exchanger; a supercooling heat exchanger having a main route and a cooling route; a supercooling expansion valve; a first temperature sensor detecting a first temperature on an inlet side of the main route; a second temperature sensor detecting a second temperature on an outlet port side of the main route; a third temperature sensor detecting a third temperature on an inlet side of a cooling route; a fourth temperature sensor detecting a fourth temperature on an outlet side of the cooling route; and a control part capable of executing a refrigerant amount determination operation. The control part acquires a determination index using temperature difference between the first temperature and the second temperature, and temperature difference between the second temperature and the third temperature while the temperature difference between the third temperature and the fourth temperature is made constant, and performs determination of whether or not the refrigerant amount of the cooling cycle device is appropriate using the refrigerant circulation amount and the determination index, in the refrigerant amount determination operation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a refrigeration cycle device and a refrigeration cycle system. [Background technology]

[0002] Patent Document 1 discloses a refrigeration device that can determine the amount of refrigerant charged, which determines the amount of refrigerant charged using the temperature efficiency of a subcooler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6590945 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a refrigeration cycle device and a refrigeration cycle system that can facilitate appropriate determination of the amount of refrigerant. [Means for solving the problem]

[0005] The refrigeration cycle device of the present disclosure includes a compressor, a heat source side heat exchanger, a subcooling heat exchanger having a main path and a cooling path, and a subcooling expansion valve that expands refrigerant that has passed through the main path and passes it through the cooling path, and further includes a first temperature sensor that detects a first temperature that is the temperature of the refrigerant on the inlet side of the main path, a second temperature sensor that detects a second temperature that is the temperature of the refrigerant on the outlet side of the main path, a third temperature sensor that detects a third temperature that is the temperature of the refrigerant on the inlet side of the cooling path, and a fourth temperature sensor that detects a fourth temperature that is the temperature of the refrigerant on the outlet side of the cooling path, and a control unit that can perform refrigerant amount determination operation, wherein in the refrigerant amount determination operation, the control unit calculates a judgment index using the temperature difference between the first temperature and the second temperature and the temperature difference between the second temperature and the third temperature while keeping the temperature difference between the third temperature and the fourth temperature constant, and determines whether the amount of refrigerant in the refrigeration cycle device is appropriate using the refrigerant circulation amount and the judgment index.

[0006] The refrigeration cycle system of the present disclosure has a refrigeration cycle device including a compressor, a heat source side heat exchanger, a subcooling heat exchanger having a main path and a cooling path, and a subcooling expansion valve that expands refrigerant that has passed through the main path and passes it through the cooling path, and the refrigeration cycle system has: a first temperature sensor that detects a first temperature that is the temperature of refrigerant on the inlet side of the main path; a second temperature sensor that detects a second temperature that is the temperature of refrigerant on the outlet side of the main path; a third temperature sensor that detects a third temperature that is the temperature of refrigerant on the inlet side of the cooling path; a fourth temperature sensor that detects a fourth temperature that is the temperature of refrigerant on the outlet side of the cooling path; a control unit that controls a temperature difference between the third temperature and the fourth temperature to be constant; and a determination unit that calculates a judgment index using the temperature difference between the first temperature and the second temperature and the temperature difference between the second temperature and the third temperature, and determines whether the amount of refrigerant in the refrigeration cycle device is appropriate using the refrigerant circulation amount and the judgment index. [Effects of the Invention]

[0007] The refrigeration cycle device and the refrigeration cycle system according to the present disclosure can facilitate determination of the refrigerant amount in the refrigeration cycle device while suppressing the influence of the installation conditions and the environment of the refrigeration cycle device, thereby facilitating appropriate determination of the refrigerant amount in the refrigeration cycle device. [Brief explanation of the drawings]

[0008] [Figure 1] Air conditioner refrigeration cycle diagram [Figure 2] Air conditioner block diagram [Figure 3] Scatter diagram showing the relationship between the refrigerant circulation volume of the air conditioner and the judgment index [Figure 4] Flowchart showing the operation of the control unit [Figure 5] FIG. 10 is a diagram showing the configuration of an air conditioning system according to a second embodiment. [Figure 6] Flowchart showing the operation of the air conditioner and the server device DETAILED DESCRIPTION OF THE INVENTION

[0009] (Findings that formed the basis of this disclosure) At the time when the inventors came up with the idea of ​​the present disclosure, methods for a system to determine the amount of refrigerant sealed in a refrigeration device included a technology for detecting by storing condensed liquid refrigerant in a high-pressure container such as a receiver, and a method for determining by detecting the supercooled state of the refrigerant at the condenser outlet. However, when a receiver is installed in a refrigeration unit, it is necessary to secure space for the receiver, which may lead to an increase in the size of the refrigeration unit's housing and an increase in weight and a decrease in economic efficiency due to the use of pressure-resistant materials.In addition, when determining the amount of refrigerant using an air heat exchanger, the state of the refrigeration cycle is greatly influenced by the installation conditions and the surrounding environment, making it difficult to properly determine the amount of refrigerant. Therefore, the present disclosure provides a refrigeration cycle device that can easily determine the amount of refrigerant.

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to the drawings. [1-1.Configuration] [1-1-1. Refrigeration cycle configuration] FIG. 1 is a refrigeration cycle diagram of an air conditioner 1 according to the first embodiment. The air conditioner 1 is an apparatus that performs air conditioning using a refrigeration cycle filled with a refrigerant. In this embodiment, the air conditioner 1 is a commercial multi-air conditioner. In this embodiment, an R410A refrigerant is used as the refrigerant. However, the refrigerant may be a refrigerant other than R410A, such as R32. The air conditioner 1 according to this embodiment is an example of a "refrigeration cycle apparatus."

[0012] The air conditioner 1 has an outdoor unit 10 installed outdoors and an indoor unit 30 installed indoors. Although only one indoor unit 30 is shown in Fig. 1, the number of indoor units 30 may be two or more.

[0013] The outdoor unit 10 has a compressor 11, a four-way valve 13, and an outdoor heat exchanger 15. The compressor 11 is a device that sucks in, compresses, and discharges gas refrigerant. In this embodiment, the compressor 11 is a two-stage compressor. Also, in this embodiment, the compressor 11 has an injection port 11a that communicates with an intermediate pressure chamber that is at an intermediate pressure. The compressor 11 can lower the temperature of the refrigerant in the intermediate pressure chamber by taking in low-temperature refrigerant through the injection port 11a. Also, an accumulator 12 for preventing liquid compression is provided on the suction side of the compressor 11.

[0014] The four-way valve 13 is a device that switches between cooling operation and heating operation of the air conditioner 1 by switching the flow path. The four-way valve 13 is connected to the discharge side of the compressor 11 and the suction side of the accumulator 12 via refrigerant piping. During cooling operation, the four-way valve 13 causes the refrigerant discharged from the compressor 11 to flow to the outdoor heat exchanger 15, and returns the refrigerant flowing from the indoor unit 30 to the accumulator 12. During heating operation, the four-way valve 13 causes the refrigerant discharged from the compressor 11 to flow to the outdoor heat exchanger 15, and returns the refrigerant flowing from the indoor unit 30 to the accumulator 12.

[0015] The outdoor heat exchanger 15 exchanges heat between the refrigerant flowing therethrough and the outdoor air. The outdoor heat exchanger 15 is, for example, a fin-tube type heat exchanger. The outdoor heat exchanger 15 functions as a condenser during cooling operation. The outdoor heat exchanger 15 is provided in a position where it is exposed to the air flow from the outdoor blower 16. The outdoor blower 16 draws outdoor air into the outdoor unit 10, passes it through the outdoor heat exchanger 15, and then blows it out of the outdoor unit 10. In this embodiment, the outdoor blower 16 is a blower whose blowing volume can be controlled, for example, an axial flow blower. The outdoor heat exchanger 15 in this embodiment corresponds to the "heat source side heat exchanger" in this disclosure.

[0016] An outdoor expansion valve 17 is connected to the liquid side of the outdoor heat exchanger 15. The outdoor expansion valve 17 is a valve whose opening can be adjusted by electronic control. The outdoor expansion valve 17 expands the liquid refrigerant mainly during heating operation. In this embodiment, two outdoor expansion valves 17 are connected in parallel to the outdoor heat exchanger 15.

[0017] The outdoor expansion valve 17 is connected to one end of an indoor / outdoor connecting liquid pipe 21 via an outdoor liquid pipe 18. The outdoor liquid pipe 18 is a refrigerant pipe having a valve 22 for connection to the indoor / outdoor connecting liquid pipe 21. The indoor / outdoor connecting liquid pipe 21 is a refrigerant pipe that connects the outdoor unit 10 and the indoor unit 30. In other words, the indoor / outdoor connecting liquid pipe 21 is located closer to the indoor unit 30 than the outdoor expansion valve 17.

[0018] The other end of the indoor / outdoor connecting liquid pipe 21 is connected to an indoor expansion valve 31 of the indoor unit 30. The indoor expansion valve 31 is a valve whose opening can be adjusted by electronic control. The indoor expansion valve 31 expands the liquid refrigerant mainly during cooling operation.

[0019] The indoor expansion valve 31 is connected to the liquid side of the indoor heat exchanger 33. The indoor heat exchanger 33 is a heat exchanger that exchanges heat between the refrigerant flowing therethrough and the indoor air. The indoor heat exchanger 33 is, for example, a fin-tube heat exchanger. The indoor heat exchanger 33 functions as an evaporator during cooling operation of the air conditioner 1. The indoor heat exchanger 33 is provided in a position where it is exposed to the air flow generated by the indoor blower 34. The indoor blower 34 draws indoor air into the indoor unit 30 and then blows it into the room via the indoor heat exchanger 33. In this embodiment, the indoor blower 34 is a blower whose blowing volume can be adjusted electronically, such as a crossflow fan. One end of the indoor-external connecting gas pipe 23 is connected to the gas side of the indoor heat exchanger 33. This is a refrigerant pipe that connects the indoor unit 30 and the outdoor unit 10. The other end of the indoor / outdoor connecting gas pipe 23 is connected to the four-way valve 13 of the outdoor unit 10 .

[0020] The outdoor unit 10 is also provided with a subcooling heat exchanger 19. The subcooling heat exchanger 19 is a heat exchanger formed with a main path 19a through which the refrigerant flows and a cooling path 19b. The cooling heat exchanger 19 is disposed in a location that is less exposed to outside air, such as a machine room of the outdoor unit 10, and is therefore less susceptible to deterioration over time than the outdoor heat exchanger 15 and the indoor heat exchanger 33. The subcooling heat exchanger 19 exchanges heat between the refrigerant flowing through the main path 19a and the refrigerant flowing through the cooling path 19b. The main path 19a of the subcooling heat exchanger 19 is connected to a midpoint of the outdoor liquid pipe 18.

[0021] One end of the cooling path 19b is connected to the branch pipe 14. The branch pipe 14 is a refrigerant pipe that branches off from the outdoor liquid pipe 18 between the main path 19a of the subcooling heat exchanger 19 and the valve 22. The branch pipe 14 is provided with a subcooling expansion valve 14a. The subcooling expansion valve 14a is a valve whose opening can be adjusted by electronic control. Mainly during cooling operation, the subcooling expansion valve 14a expands the liquid refrigerant that flows from the outdoor liquid pipe 18 into the branch pipe 14, lowering its temperature, and then allows the liquid refrigerant to flow into the cooling path 19b. That is, the subcooling heat exchanger 19 cools the refrigerant flowing through the main path 19a with the refrigerant flowing through the cooling path 19b.

[0022] The other end of the cooling path 19b is connected to an injection pipe 25. The injection pipe 25 is a refrigerant pipe that injects the refrigerant from the cooling path 19b into the compressor 11 via the injection port 11a. A bypass pipe 27 that returns the refrigerant from the injection pipe 25 to the suction side of the accumulator 12 branches off from the injection pipe 25 in the middle. The bypass pipe 27 is provided with a bypass pipe opening / closing valve 28 that is electronically controlled and opens and closes.

[0023] The outdoor unit 10 is provided with an intake-side temperature sensor 41, a discharge-side temperature sensor 42, a first temperature sensor 43, a second temperature sensor 44, a third temperature sensor 45, and a fourth temperature sensor 46, which measure the refrigerant temperatures of various parts of the air conditioner 1. Each of the temperature sensors 41 to 46 is, for example, a thermistor.

[0024] The suction-side temperature sensor 41 measures a suction-side temperature Ti, which is the refrigerant temperature on the suction side of the accumulator 12. The discharge-side temperature sensor 42 measures a discharge-side temperature To, which is the refrigerant temperature on the discharge side of the compressor 11. The first temperature sensor 43 measures a first temperature T1, which is the refrigerant temperature between the outdoor expansion valve 17 and the main path 19a of the subcooling heat exchanger 19. The second temperature sensor 44 measures a second temperature T2, which is the refrigerant temperature between the main path 19a and the valve 22. The third temperature sensor 45 measures a third temperature T3, which is the refrigerant temperature between the cooling path 19b of the subcooling heat exchanger 19 and the subcooling expansion valve 14a. The fourth temperature sensor 46 measures a fourth temperature T4, which is the refrigerant temperature in the injection pipe 25.

[0025] When the outdoor heat exchanger 15 functions as a condenser, the first temperature T1 is the refrigerant temperature at the inlet side of the main path 19a, and the second temperature T2 is the refrigerant temperature at the outlet side of the main path 19a. Similarly, the third temperature T3 is the refrigerant temperature at the inlet side of the cooling path 19b, and the fourth temperature T4 is the refrigerant temperature at the outlet side of the cooling path 19b.

[0026] The air conditioner 1 is also provided with a suction-side pressure sensor 47 and a discharge-side pressure sensor 48. The suction-side pressure sensor 47 measures the suction-side pressure Pi, which is the pressure of the refrigerant on the suction side of the accumulator 12, i.e., the suction side of the compressor 11. The discharge-side pressure sensor 48 measures the discharge-side pressure Po, which is the pressure on the discharge side of the compressor 11.

[0027] [1-1-2. Control system configuration] FIG. 2 is a diagram showing the configuration of a control system of the air conditioner 1.

[0028] 2, the air conditioner 1 has a notification unit 49. The notification unit 49 is a device that notifies specific content to people near the air conditioner 1. The notification unit 49 is, for example, a device that emits light such as an LED (Light Emitting Diode), a device that emits sound such as a speaker, or a display device such as a liquid crystal panel.

[0029] The air conditioner 1 has an operation unit 40. The operation unit 40 is a device that accepts various operations related to the air conditioner 1 from people near the air conditioner 1. The operation unit 40 is, for example, a switch, a button, or a touch panel.

[0030] The air conditioner 1 has a control device 50. In this embodiment, the control device 50 is provided in the outdoor unit 10. The control device 50 includes a processor 51 and a memory 52. ​​The processor 51 is configured with a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), or other arithmetic processing device. The memory 52 is a storage device that non-volatilely stores programs and data executed by the processor 51. The memory 52 is configured with a magnetic storage device, a semiconductor storage element, or other types of non-volatile storage device. Specifically, the memory 52 is configured with an HDD (Hard Disk Drive), a flash ROM (Read Only Memory), an SSD (Solid State Drive), or the like. The memory 52 may include RAM (Random Access Memory) that forms a work area for the processor 51. The processor 51 is an example of a "computer" in the present disclosure. The memory 52 is an example of a "storage unit" in the present disclosure.

[0031] The memory 52 stores a control program 54 executed by the processor 51. The control program 54 corresponds to the "program" in this disclosure. The memory 52 stores performance data 56. The memory 52 stores gradient data 58. Details of the performance data 56 and the gradient data 58 will be described later.

[0032] The control device 50 is provided with an outdoor unit I / F 59. The outdoor unit I / F 59 is an interface that enables the control device 50 to communicate with each part of the air conditioner 1 wirelessly or via a wired connection, and is equipped with hardware that complies with a predetermined communication standard. The control device 50 exchanges various signals and data with the various devices that are communicatively connected via the outdoor unit I / F 59.

[0033] The control device 50 is communicatively connected via the outdoor unit I / F 59 to various actuators of the air conditioner 1, such as the compressor 11, four-way valve 13, outdoor expansion valve 17, bypass pipe opening / closing valve 28, indoor expansion valve 31, and indoor blower 34. The control device 50 is also communicatively connected via the outdoor unit I / F 59 to the temperature sensors 41 to 46, pressure sensors 47 and 48, operation unit 40, and notification unit 49.

[0034] The control device 50 is also communicatively connected to an external communication device 90 via the outdoor unit I / F 59. The communication device 90 is connected to a communication network NW. The communication device 90 includes, for example, a connector for connecting a communication cable and an interface circuit for inputting and outputting signals through the connector. Furthermore, for example, the communication device 90 may be a wireless communication device that includes an antenna and a wireless circuit and is connected to the communication network NW via a wireless communication line.

[0035] The processor 51 includes, as a functional unit, a control unit 53. The control unit 53 is realized by the processor 51 executing a control program 54, through cooperation between software and hardware.

[0036] The control unit 53 operates various actuators that are communicatively connected to the control device 50, and operates the air conditioner 1. The control unit 53 also transmits and receives various signals or data to and from the sensors 41 to 48, the operation unit 40, and the communication device 90, and controls the operation of the air conditioner 1 based on the acquired signals or data.

[0037] The control unit 53 is configured to be able to perform a refrigerant amount determination operation in addition to the heating operation and cooling operation of the air conditioner 1. The refrigerant amount determination operation is an operation for determining the amount of refrigerant sealed in the refrigeration cycle of the air conditioner 1. The refrigerant amount determination operation will be described in detail later.

[0038] The air conditioner 1 is communicatively connected to a remote system 100 via a communication device 90 and a communication network NW. The remote system 100 is a device communicatively connected to the communication network NW. The remote system 100 is, for example, a server device equipped with a processor. The remote system 100 is configured to be able to transmit operation signals via the communication network NW to cause the air conditioner 1 to perform various operations.

[0039] The remote system 100 may be connected to multiple air conditioners 1. Hereinafter, when distinguishing between the air conditioners 1, they will be referred to as air conditioners 1A and 1B. The air conditioners 1A and 1B may be installed in different situations. For example, the length of the refrigerant piping of the air conditioners 1A and 1B, the number of indoor units 30, and the positional relationship between the outdoor unit 10 and the indoor units 30 may be different from each other. Furthermore, the environments in which the air conditioners 1A and 1B are installed, such as the ambient temperature, may be different from each other.

[0040] [1-2. Operation] The operation of the air conditioner 1 configured as described above will now be described. The control unit 53 is capable of executing a refrigerant amount determination operation, which is an operation for determining whether the amount of refrigerant filled in the air conditioner 1 is appropriate. During the refrigerant amount determination operation, the control unit 53 executes a determination operation for determining whether the refrigerant amount is appropriate while executing constant heating degree control and constant density control, in order to determine whether the refrigerant amount is appropriate while suppressing the effects of the installation conditions and environment of the air conditioner 1. Below, we will first explain the constant heating degree control and constant density control, and then explain the principles of the determination operation. After that, we will explain a series of operations of the control unit 53, including the constant heating degree control, constant density control, and the determination operation.

[0041] [1-2-1. Details of constant heating control and constant density control] The constant heating degree control is a control for maintaining a constant difference in the degree of subcooling of the refrigerant at the inlet and outlet of the cooling path 19b. The constant density control is a control for maintaining a constant density of the refrigerant at the outlet of the main path 19a. The constant heating degree control and constant density control are performed when the outdoor heat exchanger 15 functions as a condenser.

[0042] Constant degree of heating control is achieved by the control unit 53 controlling each unit of the air conditioner 1 so that the temperature difference T4-T3 between the third temperature T3 and the fourth temperature T4 is a constant value. Specifically, in constant degree of heating control, when the temperature difference T4-T3 becomes larger than a constant value, the control unit 53 increases the opening of the subcooling expansion valve 14a to increase the amount of refrigerant flowing into the cooling path 19b. Conversely, when the temperature difference T4-T3 becomes smaller than a constant value, the control unit 53 decreases the opening of the subcooling expansion valve 14a to decrease the amount of refrigerant flowing into the cooling path 19b.

[0043] Constant density control is achieved by the control unit 53 controlling each part of the air conditioner 1 so that the second temperature T2 remains constant. When the second temperature T2 is lower than the saturation temperature at the pressure on the high-pressure side of the refrigeration cycle, the refrigerant at the outlet of the main path 19a is liquid refrigerant. In this state, the density of the refrigerant at the outlet of the main path 19a can be calculated from the second temperature T2. In other words, by controlling the second temperature T2 to remain constant, the density of the refrigerant at the outlet of the main path 19a can be kept constant. Specifically, in the constant density control, when the second temperature T2 drops below a constant value and the density increases, the control unit 53 increases the rotation speed of the compressor 11 and reduces the airflow rate of the outdoor blower 16. This increases the second temperature T2 and reduces the refrigerant density. Conversely, when the second temperature T2 rises above a constant value and the density decreases, the control unit 53 decreases the rotation speed of the compressor 11 and increases the airflow rate of the outdoor blower 16. This decreases the second temperature T2 and increases the density.

[0044] When the constant heating degree control and the constant density control are being performed, it is possible to determine the amount of refrigerant while suppressing the influence of the environment.

[0045] [1-2-2. Principle of Judgment Operation] Figure 3 is a scatter plot showing the relationship between the refrigerant circulation amount q of the air conditioner 1 and the judgment index D. Note that Figure 3 shows the relationship when constant heating control and constant density control are being executed. The graph in Figure 3 plots a point where the amount of refrigerant filled into the air conditioner 1 is the appropriate amount, a point where the amount is 500 g less than the appropriate amount (98.0% of the appropriate amount), a point where the amount is 1 kg less than the appropriate amount (95.9% of the appropriate amount), and a point where the amount is 70% of the appropriate amount.

[0046] In this embodiment, the decision index D is the product of ΔSCL and ΔLDC. That is, the decision index D is given by the following formula (A). D=ΔSCL*ΔLDC (A)

[0047] ΔSCL indicates the amount of decrease in the temperature of the refrigerant when the refrigerant passes through the main path 19a. In other words, ΔSCL corresponds to the absolute value of the difference between the first temperature T1 and the second temperature T2. ΔSCL is a larger value when the amount of refrigerant in the air conditioner 1 is appropriate than when the amount of refrigerant is less than the appropriate amount. ΔSCL is given by the following equation (B): ΔSCL=|T1-T2| (B)

[0048] ΔLDC indicates the amount of drop in the temperature of the refrigerant when it leaves the main path 19a and passes through the subcooling expansion valve 14a. In other words, ΔLDC corresponds to the absolute value of the difference between the second temperature T2 and the third temperature T3. When the amount of refrigerant in the air conditioner 1 is appropriate, ΔLDC is greater than when the amount of refrigerant is less than the appropriate amount. ΔLDC is given by the following equation (C): ΔLDC=|T2-T3| (C)

[0049] Furthermore, since the liquid refrigerant leaving the main path 19a is decompressed and becomes a gas-liquid two-phase state when passing through the subcooling expansion valve 14a, the pressure of the refrigerant after passing through the subcooling expansion valve 14a can be converted from the third temperature T3. In other words, ΔLDC and the amount of pressure reduction by the subcooling expansion valve 14a are values ​​that can be converted into each other. For example, the greater the amount of pressure reduction by the subcooling expansion valve 14a, the larger ΔLDC becomes. Therefore, the amount of pressure reduction by the subcooling expansion valve 14a or a value obtained by converting the amount of pressure reduction by the subcooling expansion valve 14a may be used as ΔLDC.

[0050] As shown in FIG. 3, the value of the judgment index D increases as the refrigerant circulation amount q increases, both when the amount of refrigerant filled in the air conditioner 1 is appropriate and when it is less than appropriate. In other words, the rate of change R of the judgment index D with respect to the change in the refrigerant circulation amount q is mainly positive. The rate of change R can be calculated by any method using two or more pairs of values ​​of the refrigerant circulation amount q and the judgment index D. For example, if the judgment index D takes a value D1 when the refrigerant circulation amount q during the refrigerant amount judgment operation takes a value q1, and the judgment index D takes a value D2 when the refrigerant circulation amount q during the refrigerant amount judgment operation takes a value q2 different from q1, the rate of change R can be calculated using the following formula (D): R = (D2 - D1) / (q2 - q1) (D) However, instead of using formula (D), the rate of change R may be calculated by first-order approximation by applying the least squares method or the like to two or more pairs of values ​​of the refrigerant circulation amount q and the value of the judgment index D.

[0051] Furthermore, the rate of change R of the judgment index D relative to the change in the refrigerant circulation amount q becomes larger when the amount of refrigerant is large. In particular, the rate of change R when the amount of refrigerant filled in the air conditioner 1 is the appropriate amount is significantly larger than the rate of change R when the refrigerant amount is filled to 98.0% of the appropriate amount.

[0052] The determination operation of this embodiment utilizes this property to determine whether the amount of refrigerant filled in the air conditioner 1 is appropriate. More specifically, the determination operation of this embodiment determines whether the amount of refrigerant filled in the air conditioner 1 is less than the appropriate amount. This makes it easy to detect with high accuracy that the amount of refrigerant is insufficient, particularly when the amount of refrigerant filled in the air conditioner 1 is slightly less than the appropriate amount.

[0053] That is, the control unit 53 calculates multiple pairs of the refrigerant circulation amount q and the judgment index D from the operating data obtained during the execution of the refrigerant amount determination operation. The control unit 53 also calculates the rate of change R using the multiple calculated pairs of the refrigerant circulation amount q and the judgment index D. The control unit 53 then determines that the amount of refrigerant filled into the air conditioner 1 is less than the appropriate amount when the calculated rate of change R is less than the reference rate of change R0. In other words, the control unit 53 determines that the amount of refrigerant filled into the air conditioner 1 is not appropriate when the calculated rate of change R is equal to or greater than the reference rate of change R0. In other words, the control unit 53 determines that the amount of refrigerant filled into the air conditioner 1 is appropriate when the calculated rate of change R is equal to or greater than the reference rate of change R0.

[0054] The refrigerant circulation amount q is the mass of refrigerant discharged from the compressor 11 per unit time. The refrigerant circulation amount q is calculated using the compressor rotation speed, cylinder volume, mechanical efficiency, adiabatic efficiency, and compressor intake refrigerant density. Because a complex formula is required to calculate the compressor intake refrigerant density, a value converted from the compressor rotation speed may be used as the refrigerant circulation amount q.

[0055] [1-2-3. Overview of refrigerant amount determination operation] FIG. 4 is a flowchart showing the operation of the control unit 53, and shows the operation during refrigerant quantity determination operation. The operation in FIG. 4 is executed when refrigerant is charged immediately after installation of the air conditioner 1, immediately after refrigerant is charged into the air conditioner 1, during regular inspection or simple inspection of the air conditioner 1, etc. The operation in FIG. 4 is executed when triggered by the control unit 53 detecting a first operation signal transmitted from the remote system 100, or by the control unit 53 detecting a first operation on the operation unit 40. The first operation signal is a signal that causes the air conditioner 1 to perform refrigerant quantity determination operation. The first operation is an operation that causes the air conditioner 1 to perform refrigerant quantity determination operation.

[0056] In step SA1, the control unit 53 controls the four-way valve 13 to connect the discharge side of the compressor 11 to the outdoor heat exchanger 15. By executing step SA1, the liquid refrigerant discharged from the compressor 11 and condensed in the outdoor heat exchanger 15 passes as a liquid through the main path 19a of the subcooling heat exchanger 19. Thereafter, part of the liquid refrigerant flows into the branch pipe 14, expands in the subcooling expansion valve 14a, becomes low-temperature flash gas, and flows into the cooling path 19b of the subcooling heat exchanger 19. As a result, in the subcooling heat exchanger 19, heat is transferred from the liquid refrigerant flowing through the main path 19a to the low-temperature refrigerant flowing through the cooling path 19b.

[0057] In this way, by executing step SA1, the outdoor heat exchanger 15 is brought into a state where it functions as a condenser. That is, by executing step SA1, the control unit 53 is able to execute the constant subcooling control and constant density control described above. After completing step SA1, the operation of the control unit 53 proceeds to step SA2.

[0058] In step SA2, the control unit 53 starts the constant supercooling control and constant density control described above. After completing step SA2, the operation of the control unit 53 proceeds to step SA3.

[0059] Next, the control unit 53 executes the determination operation, which is the operation from step SA3 to step SA7. Note that the control unit 53 continues the constant supercooling degree control and the constant density control during the determination operation.

[0060] In step SA3, the control unit 53 samples a pair of the value qi of the refrigerant circulation amount q and the value Di of the judgment index D when the refrigerant circulation amount q is the value qi. The control unit 53 obtains the value qi using the rotation speed of the compressor 11, etc. The control unit 53 also obtains the value Di by substituting the measured values ​​of the temperature sensors 43 to 46 when the refrigerant circulation amount q is the value qi into equations (A) to (C).

[0061] In this embodiment, control unit 53 samples multiple pairs of value qi of refrigerant circulation amount q and value Di of judgment index D when refrigerant circulation amount q is value qi. That is, control unit 53 samples value qi and value Di corresponding to value qi multiple times while controlling the rotation speed of compressor 11 and changing the refrigerant circulation amount q. After completing sampling of value qi and value Di corresponding to value qi in step SA3, control unit 53 proceeds to step SA4.

[0062] In step SA4, control unit 53 calculates value R1 of rate of change R using multiple pairs of values ​​qi and Di acquired in step SA3. In this embodiment, control unit 53 calculates value R1 by substituting the two pairs of values ​​qi and Di acquired in step SA3 into equation (D).

[0063] In step SA5, control unit 53 determines whether value R1 of rate of change R calculated in step SA3 is equal to or greater than reference rate of change R0. In this embodiment, control unit 53 uses a value included in gradient data 58 pre-stored in memory 52 as the value of reference rate of change R0. Control unit 53 reads gradient data 58 from memory 52 to acquire reference rate of change R0, and if value R1 is equal to or greater than reference rate of change R0 (step SA5: YES), the operation of control unit 53 proceeds to step SA6. If value R1 is less than reference rate of change R0 (step SA5: NO), the operation of control unit 53 proceeds to step SA7.

[0064] In step SA6, the control unit 53 determines that the amount of refrigerant filled into the air conditioner 1 is appropriate. Then, the process proceeds to step SA8.

[0065] In step SA7, the control unit 53 determines that the amount of refrigerant filled in the air conditioner 1 is insufficient. Then, the process proceeds to step SA8.

[0066] In step SA8, the control unit 53 stores in the memory 52 as performance data 56 the plurality of pairs of the values ​​qi and Di obtained in step SA3 and the value R1 of the rate of change R calculated in step SA4.

[0067] In step SA9, the control unit 53 notifies the determination result of step SA6 or step SA7. The notification of the determination result may be executed, for example, by causing the notification unit 49 to emit sound or light, or by causing the notification unit 49 to display an indication, under the control of the control unit 53. Furthermore, for example, the control unit 53 may notify the determination result to the remote system 100 via the communication device 90, the communication network NW, etc. When the execution of step SA4 is completed, the control unit 53 ends the refrigerant amount determination operation.

[0068] [1-3. Effects, etc.] As described above, in this embodiment, the air conditioner 1 includes the compressor 11, the outdoor heat exchanger 15, the subcooling heat exchanger 19 having the main path 19a and the cooling path 19b, and the subcooling expansion valve 14a that expands the refrigerant that has passed through the main path 19a and passes it through the cooling path 19b. The air conditioner 1 includes a first temperature sensor 43 that detects a first temperature T1, which is the temperature of the refrigerant on the inlet side of the main path 19a, a second temperature sensor 44 that detects a second temperature T2, which is the temperature of the refrigerant on the outlet side of the main path 19a, and a third temperature sensor 45 that detects a third temperature T3, which is the temperature of the refrigerant on the inlet side of the cooling path 19b. The air conditioner 1 is equipped with a sensor 45, a fourth temperature sensor 46 that detects a fourth temperature T4, which is the temperature of the refrigerant at the outlet side of the cooling path 19b, and a control unit 53 that is capable of performing refrigerant quantity determination operation, and in the refrigerant quantity determination operation, the control unit 53 calculates a determination index D using ΔSCL, which is the temperature difference between the first temperature T1 and the second temperature T2, and ΔLDC, which is the temperature difference between the second temperature T2 and the third temperature T3, while keeping the temperature difference between the third temperature T3 and the fourth temperature T4 constant, and uses the refrigerant circulation amount q and the determination index D to determine whether the refrigerant amount in the air conditioner 1 is appropriate. This makes it easier to determine the amount of refrigerant in the air conditioner 1 while suppressing the effects of the installation conditions and environment of the air conditioner 1. This makes it easier to determine the amount of refrigerant in the air conditioner 1 appropriately.

[0069] As in this embodiment, the control unit 53 may be configured to perform control to keep the second temperature T2 constant during the refrigerant amount judging operation. This makes it easier to determine the amount of refrigerant in the air conditioner 1 while suppressing the effects of the installation conditions and environment of the air conditioner 1. This makes it easier to determine the amount of refrigerant in the air conditioner 1 appropriately.

[0070] As in this embodiment, the control unit 53 may be configured to use, as the judgment index D during the refrigerant amount judgment operation, the product of ΔSCL, which is the temperature difference between the first temperature T1 and the second temperature T2, and ΔLDC, which is the temperature difference between the second temperature T2 and the third temperature T3. This makes it easier to determine whether the amount of refrigerant in the air conditioner 1 is appropriate when it is close to the appropriate amount. This makes it easier to properly determine the amount of refrigerant in the refrigeration cycle device.

[0071] As in this embodiment, the control unit 53 may be configured to determine that the amount of refrigerant in the air conditioner 1 is appropriate when the rate of change R of the judgment index D with respect to the change in the refrigerant circulation amount q is greater than the reference rate of change R0 during the refrigerant amount judgment operation. This makes it easier to determine whether the amount of refrigerant in the refrigeration cycle device is less than the appropriate amount when the amount is close to the appropriate amount, thereby making it easier to appropriately determine the amount of refrigerant in the refrigeration cycle device. In particular, in this embodiment, since the judgment index D is the product of ΔSCL and ΔLDC, when the amount of refrigerant is less than the appropriate amount, the judgment index D is likely to have a small value, making it easy to detect a shortage of the amount of refrigerant.

[0072] 2. Second Embodiment Next, a second embodiment of the present disclosure will be described. In the second embodiment, the matters described in the first embodiment will be omitted, and only the differences from the first embodiment will be described. Unlike the first embodiment, the second embodiment is configured to include a server device 70 that determines the amount of refrigerant in the air conditioner 1.

[0073] [2-1.Configuration] FIG. 5 is a diagram showing the configuration of an air conditioning system 1000 according to the second embodiment. The air conditioning system 1000 has one or more air conditioners 1 connected to a communication network NW via a communication device 90, and a server device 70 connected to the communication network NW. The air conditioning system 1000 corresponds to an example of a "refrigeration cycle system" in the present disclosure.

[0074] The server device 70 includes a server control device 71 and a server communication device 74 .

[0075] The server communication device 74 is connected to the communication network NW and communicates with the air conditioner 1 in accordance with the control of the server control device 71. The server communication device 74 includes, for example, a connector for connecting a communication cable and an interface circuit for inputting and outputting signals via the connector. Alternatively, for example, the server communication device 74 may be a wireless communication device that includes an antenna and a wireless circuit and connects to the communication network NW via a wireless communication line.

[0076] The server control device 71 has a server processor 72 and a server memory 73. The server processor 72 is configured by a CPU, an MPU, or other arithmetic processing device. The server memory 73 is a storage device that non-volatilely stores programs and data executed by the server processor 72. The server memory 73 is configured by a magnetic storage device, a semiconductor storage element, or other types of non-volatile storage device. Specifically, the server memory 73 is configured by an HDD, a flash ROM, an SSD, etc. The server memory 73 may include RAM that forms a work area for the processor 51. The server processor 72 is an example of a "computer" in the present disclosure. The server memory 73 is an example of a "storage unit" in the present disclosure.

[0077] The server memory 73 stores a control program 76 executed by the server processor 72. The control program 76 corresponds to the "program" in this disclosure. The server memory 73 stores performance data 77 similar to the performance data 56 in the memory 52. ​​The server memory 73 stores gradient data 78 similar to the gradient data 58 in the memory 52.

[0078] The server processor 72 includes, as a functional unit, a server control unit 75. The server control unit 75 is realized by the server processor 72 executing a control program 76, through cooperation between software and hardware.

[0079] The server control unit 75 communicates with the air conditioner 1 via the server communication device 74 and issues operation instructions to the air conditioner 1. The operation instructions may include instructions to the air conditioner 1 to execute constant heating degree control and constant density control for determining the amount of refrigerant. When the control unit 53 of the air conditioner 1 detects an instruction to execute constant heating degree control and constant density control, it controls each device as described in the first embodiment and executes constant heating degree control and constant density control.

[0080] The server control unit 75 also makes a determination regarding the amount of refrigerant sealed in the refrigeration cycle of the air conditioner 1. In detail, when making the determination, the server control unit 75 uses a set of the value qi of the circulating refrigerant amount q sampled in the air conditioner 1, the value T1i of the first temperature T1, the value T2i of the second temperature T2, and the value T3i of the third temperature T3. The server control unit 75 corresponds to an example of a "determination unit" in the present disclosure.

[0081] [2-2. Operation] Fig. 6 is a flowchart showing the operation of the air conditioner 1 and server device 70 in embodiment 2. In Fig. 6, flowchart FB shows the operation of the server device 70, and flowchart FC shows the operation of the air conditioner 1. The operation in Fig. 6 is started at any timing, such as when the server device 70 detects that the date and time for a regular inspection of the amount of refrigerant in the air conditioner 1 has arrived.

[0082] 6, in step SB1, the server control unit 75 sends a refrigerant amount determination start signal to the air conditioner 1. The refrigerant amount determination start signal includes an instruction to cause the air conditioner 1 to execute constant heating degree control and constant density control. The refrigerant amount determination start signal also includes an instruction to cause the air conditioner 1 to sample a set of the value qi of the refrigerant circulation amount q, the value T1i of the first temperature T1, the value T2i of the second temperature T2, and the value T3i of the third temperature T3, and send these to the server device 70.

[0083] In step SC1, the control unit 53 receives a signal via the communication device 90 to start determining the amount of refrigerant.

[0084] In steps SC2 and SC3, the control unit 53 switches the four-way valve 13 in the same way as in steps SA1 and SA2 in FIG. 4, and starts constant supercooling control and constant density control.

[0085] In step SC4, control unit 53 samples two or more pairs of value qi of refrigerant circulation amount q, value T1i of first temperature T1, value T2i of second temperature T2, and value T3i of third temperature T3. As in step SA3 of Fig. 4, control unit 53 acquires value qi using the rotation speed of compressor 11, etc. Control unit 53 also acquires value T1i of first temperature T1, value T2i of second temperature T2, and value T3i of third temperature T3, which are measured values ​​of each temperature sensor 43-45 when refrigerant circulation amount q is value qi.

[0086] In step SC5, the control unit 53 transmits to the server device 70 the data set of the values ​​qi, T1i, T2i, and T3i sampled in step SC4.

[0087] In step SB2, the server control unit 75 receives the transmitted data set of values ​​qi, T1i, T2i, and T3i via the server communication device 74.

[0088] In step B3, the server control unit 75 substitutes the received data set of values ​​T1i, T2i, and T3i into formulas (A) to (C) to find the value Di of the judgment index D. Then, the server control unit 75 calculates the value R1 of the rate of change R from the set of values ​​qi and Di. Formula (D) or the like may be used to calculate the value R1.

[0089] In step SB4, the server control unit 75 determines whether the calculated value R1 is equal to or greater than the reference rate of change R0. In this embodiment, the server control unit 75 uses a value included in the gradient data 78 pre-stored in the server memory 73 as the value of the reference rate of change R0. If the value R1 is equal to or greater than the reference rate of change R0 (step SB4: YES), the operation of the server control unit 75 proceeds to step SB5. If the value R1 is less than the reference rate of change R0 (step SB4: NO), the operation of the server control unit 75 proceeds to step SB5.

[0090] In step SB5, the server control unit 75 determines that the amount of refrigerant filled in the air conditioner 1 is appropriate. Then, the process proceeds to step SB7.

[0091] In step SB6, the server control unit 75 determines that the amount of refrigerant filled in the air conditioner 1 is insufficient. Then, the process proceeds to step SB7.

[0092] In step SB7, the server control unit 75 stores, as performance data 77 in the server memory 73, a plurality of pairs of the values ​​qi and Di calculated in step SB3 and the calculated value R1 of the rate of change R.

[0093] In step SB8, the server control unit 75 transmits the determination result made in step SB5 or step SB6 to the air conditioner 1. Note that the server control unit 75 may transmit the determination result to, for example, a terminal such as a smartphone owned by the user who uses the air conditioner 1.

[0094] In step SC6, the control unit 53 receives the determination result via the communication device 90. Thereafter, in step SC7, the control unit 53 notifies the determination result in the same manner as in step SA9 in FIG.

[0095] [2-3. Effects, etc.] As described above, in this embodiment, the air conditioning system 1000 is an air conditioning system having an air conditioner 1 equipped with a compressor 11, an outdoor heat exchanger 15, a subcooling heat exchanger 19 having a main path 19a and a cooling path 19b, and a subcooling expansion valve 15a that expands the refrigerant that has passed through the main path 19a and passes it through the cooling path 19b, the air conditioning system having a first temperature sensor 43 that detects a first temperature T1 that is the temperature of the refrigerant on the inlet side of the main path 19a, a second temperature sensor 44 that detects a second temperature T2 that is the temperature of the refrigerant on the outlet side of the main path 19a, and a second temperature sensor 45 that detects a second temperature T3 that is the temperature of the refrigerant on the inlet side of the cooling path 19b. The air conditioner 1 includes a third temperature sensor 45 that detects a third temperature T3, which is the temperature of the refrigerant; a fourth temperature sensor 46 that detects a fourth temperature T4, which is the temperature of the refrigerant at the outlet side of the cooling path 19b; a control unit 53 that controls the temperature difference T4-T3 between the third temperature T3 and the fourth temperature T4 to be constant; and a server control unit 75 that calculates a judgment index D using ΔSCL, which is the temperature difference between the first temperature T1 and the second temperature T2, and ΔLDC, which is the temperature difference between the second temperature T2 and the third temperature T3, and uses the refrigerant circulation amount q and the judgment index D to determine whether the amount of refrigerant in the air conditioner 1 is appropriate. This makes it easier to determine the amount of refrigerant in the air conditioner 1 while suppressing the effects of the installation conditions and environment of the air conditioner 1. This makes it easier to determine the amount of refrigerant in the air conditioner 1 appropriately.

[0096] (Other embodiments) As described above, the first and second embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the first and second embodiments to create new embodiments. Therefore, other embodiments will be exemplified below.

[0097] In the first and second embodiments, the air conditioner 1 has been described as an example of a refrigeration cycle device, but the refrigeration cycle device is not limited to the air conditioner 1. For example, the refrigeration cycle device may be a refrigerator or a freezer showcase. Furthermore, the freezer showcase may have a separate outdoor unit or may have a built-in refrigeration cycle.

[0098] In the first and second embodiments, the product of ΔSCL and ΔLDC has been described as an example of the judgment index D. However, this is just one example. The judgment index D may also be the sum of ΔSCL and ΔLDC. Furthermore, the judgment index D may also be a value obtained by converting the values ​​of ΔSCL and ΔLDC using a table or the like.

[0099] In the first and second embodiments, the control unit 53 determines whether the amount of refrigerant in the air conditioner 1 is appropriate using the rate of change R of the judgment index D, but this is just one example. For example, the control unit 53 may be configured to determine that the amount of refrigerant is appropriate when the value of the judgment index D when the amount of refrigerant circulating q is a specific value is equal to or greater than a reference value, and to determine that the amount of refrigerant is inappropriate when the value is less than the reference value.

[0100] In the first and second embodiments, the control unit 53 or the server control unit 75 uses the value included in the gradient data 58, 78 stored in advance in the memory 52 or the server memory 73 as the reference rate of change R0 in the determination at step SA5 or step SB4. However, this is merely an example. The value R1 of the rate of change R from the past refrigerant amount determination operation included in the performance data 56 may be used as the reference rate of change R0. For example, the control unit 53 or the server control unit 75 may read the value R1 of the rate of change R obtained during the refrigerant amount determination operation when refrigerant charging of the air conditioner 1 was completed from the performance data 56, 77, and use this value as the reference rate of change R0 either directly or after correction. This allows the data at the time refrigerant charging was completed to be considered appropriate, making it possible to determine whether the current refrigerant amount is appropriate, thereby facilitating the detection of refrigerant leaks, etc.

[0101] The various parameters of the refrigeration cycle, such as the refrigerant temperature and pressure, used for various operations such as determination by the control unit 53 and the server control unit 75 may be values ​​measured directly by various sensors, or may be values ​​converted from the measurements of the various sensors. Furthermore, the various parameters may be measured at any location in the air conditioner 1, as long as the parameters have values ​​equivalent to those described in the first and second embodiments.

[0102] The units shown in Figures 2 and 5 are merely examples, and the specific implementation form is not particularly limited. In other words, it is not necessary to implement hardware corresponding to each unit individually, and it is of course possible to configure the units so that the functions are realized by a single processor executing a program. Furthermore, some of the functions realized by software in the above-described embodiments may be implemented as hardware, or some of the functions realized by hardware may be implemented as software. The specific detailed configurations of the air conditioner 1, server device 70, communication device 90, remote system 100, and other devices may also be changed as desired without departing from the spirit of the present disclosure.

[0103] Furthermore, the step units of operation shown in Figures 4 and 6 are divided according to the main processing content to make it easier to understand the operation of the air conditioner 1, and this disclosure is not limited by the way the processing units are divided or their names.

[0104] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[0105] (Addendum) The above description of the embodiments discloses the following techniques. (Technology 1) A refrigeration cycle device including a compressor, a heat source side heat exchanger, a subcooling heat exchanger having a main path and a cooling path, and a subcooling expansion valve that expands refrigerant that has passed through the main path and passes it through the cooling path, the refrigeration cycle device including: a first temperature sensor that detects a first temperature that is the temperature of the refrigerant on the inlet side of the main path; a second temperature sensor that detects a second temperature that is the temperature of the refrigerant on the outlet side of the main path; a third temperature sensor that detects a third temperature that is the temperature of the refrigerant on the inlet side of the cooling path; and a fourth temperature sensor that detects a fourth temperature that is the temperature of the refrigerant on the outlet side of the cooling path; and a control unit capable of performing a refrigerant amount determination operation, wherein in the refrigerant amount determination operation, the control unit calculates a determination index using the temperature difference between the first temperature and the second temperature and the temperature difference between the second temperature and the third temperature while keeping the temperature difference between the third temperature and the fourth temperature constant, and determines whether the amount of refrigerant in the refrigeration cycle device is appropriate using the refrigerant circulation amount and the determination index. This makes it easier to determine the amount of refrigerant in the refrigeration cycle device while suppressing the effects of the installation conditions and environment of the refrigeration cycle device, thereby making it easier to appropriately determine the amount of refrigerant in the refrigeration cycle device.

[0106] (Technical 2) The refrigeration cycle device according to Technical 1, wherein the control unit performs control to keep the second temperature constant during the refrigerant amount determination operation. This makes it easier to determine the amount of refrigerant in the refrigeration cycle device while suppressing the effects of the installation conditions and environment of the refrigeration cycle device, thereby making it easier to appropriately determine the amount of refrigerant in the refrigeration cycle device.

[0107] (Technology 3) The refrigeration cycle device according to Technology 1 or 2, wherein the control unit uses, as the judgment index during the refrigerant amount judgment operation, the product of the temperature difference between the first temperature and the second temperature and the temperature difference between the second temperature and the third temperature. This makes it easier to determine whether the amount of refrigerant in the refrigeration cycle device is appropriate when the amount is close to the appropriate amount. Therefore, it is easier to appropriately determine the amount of refrigerant in the refrigeration cycle device.

[0108] (Technology 4) A refrigeration cycle device described in any one of Technologies 1 to 3, wherein the control unit determines that the refrigerant amount of the refrigeration cycle device is appropriate when, during the refrigerant amount determination operation, the rate of change of the determination index relative to the change in the refrigerant circulation amount is greater than a reference change rate. This makes it easier to determine whether the amount of refrigerant in the refrigeration cycle device is less than the appropriate amount when the amount is close to the appropriate amount, thereby making it easier to appropriately determine the amount of refrigerant in the refrigeration cycle device.

[0109] (Technology 5) A refrigeration cycle system having a refrigeration cycle device including a compressor, a heat source side heat exchanger, a subcooling heat exchanger having a main path and a cooling path, and a subcooling expansion valve that expands refrigerant that has passed through the main path and passes it through the cooling path, the refrigeration cycle system further comprising: a first temperature sensor that detects a first temperature that is the temperature of refrigerant on the inlet side of the main path; a second temperature sensor that detects a second temperature that is the temperature of refrigerant on the outlet side of the main path; a third temperature sensor that detects a third temperature that is the temperature of refrigerant on the inlet side of the cooling path; and a fourth temperature sensor that detects a fourth temperature that is the temperature of refrigerant on the outlet side of the cooling path; a control unit that controls a temperature difference between the third temperature and the fourth temperature to be constant; and a determination unit that calculates a judgment index using the temperature difference between the first temperature and the second temperature and the temperature difference between the second temperature and the third temperature, and determines whether the amount of refrigerant in the refrigeration cycle device is appropriate using the refrigerant circulation amount and the judgment index. This makes it easier to determine the amount of refrigerant in the refrigeration cycle device while suppressing the effects of the installation conditions and environment of the refrigeration cycle device, thereby making it easier to appropriately determine the amount of refrigerant in the refrigeration cycle device. [Industrial Applicability]

[0110] The present disclosure is applicable to refrigeration cycle devices, specifically to various devices that constitute a refrigeration cycle, such as air conditioners, commercial refrigerators, showcases, and the like. [Explanation of symbols]

[0111] 1, 1A, 1B Air conditioner (refrigeration cycle device) 10 Outdoor unit 11 Compressor 11a injection port 12 Accumulator 13 Four-way valve 14 Branch piping 14a Subcooling expansion valve 15 Outdoor heat exchanger (heat source side heat exchanger) 16 Outdoor blower 17 Outdoor expansion valve 18 Outdoor liquid pipe 19 Subcooling heat exchanger Route 19a 19b Cooling path 21 Internal and external connecting liquid pipe 22 valves 23 Internal and external gas pipe connection 25 Injection piping 27 Bypass pipe 28 Bypass pipe on-off valve 30 Indoor unit 31 Indoor expansion valve 33 Indoor heat exchanger 34 Indoor fan 40 Control section 41 Intake side temperature sensor 42 Discharge side temperature sensor 43 First temperature sensor 44 Second temperature sensor 45 Third temperature sensor 46 4th temperature sensor 47 Intake side pressure sensor 48 Discharge side pressure sensor 49 Information Department 50 Control device 51 processors 52 memory 53 Control Unit 54 Control Program 56 Performance Data 58 Gradient Data 70 Server equipment 71 Server control device 72 Server Processors 73 Server Memory 74 Server communication device 75 Server control unit (determination unit) 76 Control Program 77 Performance Data 78 Gradient Data 59 Outdoor unit I / F 90 Communication Equipment 100 Remote System 1000 Air conditioning system (refrigeration cycle system) NW communication network

Claims

1. A compressor; a heat source side heat exchanger; a subcooling heat exchanger having a main path and a cooling path; a subcooling expansion valve that expands the refrigerant that has passed through the main path and passes it through the cooling path, a first temperature sensor that detects a first temperature, which is the temperature of the refrigerant at the inlet side of the main path; a second temperature sensor that detects a second temperature, which is the temperature of the refrigerant at the outlet side of the main path; a third temperature sensor that detects a third temperature, which is the temperature of the refrigerant at the inlet side of the cooling path; a fourth temperature sensor that detects a fourth temperature, which is the temperature of the refrigerant at an outlet side of the cooling path; a control unit capable of executing a refrigerant amount determination operation, In the refrigerant amount determination operation, the control unit calculates a determination index using a temperature difference between the first temperature and the second temperature and a temperature difference between the second temperature and the third temperature while keeping the temperature difference between the third temperature and the fourth temperature constant, and determines whether the amount of refrigerant in the refrigeration cycle device is appropriate using the refrigerant circulation amount and the determination index. Refrigeration cycle equipment.

2. The control unit performs control to keep the second temperature constant during the refrigerant amount determination operation. The refrigeration cycle device according to claim 1.

3. the control unit uses, as the determination index, a product of a temperature difference between the first temperature and the second temperature and a temperature difference between the second temperature and the third temperature, in the refrigerant amount determination operation. The refrigeration cycle device according to claim 1 or 2.

4. the control unit determines that the amount of refrigerant in the refrigeration cycle device is appropriate when a change rate of the determination index with respect to a change in the amount of refrigerant circulating is greater than a reference change rate during the refrigerant amount determination operation. The refrigeration cycle device according to claim 1 or 2.

5. A refrigeration cycle system having a refrigeration cycle device including a compressor, a heat source side heat exchanger, a subcooling heat exchanger having a main path and a cooling path, and a subcooling expansion valve that expands a refrigerant that has passed through the main path and passes it through the cooling path, a first temperature sensor that detects a first temperature, which is the temperature of the refrigerant at the inlet side of the main path; a second temperature sensor that detects a second temperature, which is the temperature of the refrigerant at the outlet side of the main path; a third temperature sensor that detects a third temperature, which is the temperature of the refrigerant at the inlet side of the cooling path; a fourth temperature sensor that detects a fourth temperature, which is the temperature of the refrigerant at an outlet side of the cooling path; a control unit that controls a temperature difference between the third temperature and the fourth temperature to be constant; a determination unit that calculates a determination index using a temperature difference between the first temperature and the second temperature and a temperature difference between the second temperature and the third temperature, and determines whether the amount of refrigerant in the refrigeration cycle device is appropriate using the refrigerant circulation amount and the determination index. Refrigeration cycle system.

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