Refrigeration Cycle Equipment

Abstract

This refrigeration cycle device comprises a refrigerant circuit, a compressor, a condenser, an evaporator, a branch path, an expansion valve, an adjustment valve, a first temperature detection unit, a first pressure detection unit, a second temperature detection unit, a second pressure detection unit, and a control unit. The control unit determines excess or deficiency of an encapsulated quantity of refrigerant encapsulated in the refrigerant circuit on the basis of relationships among the temperature of refrigerant discharged from the compressor detected by the first temperature detection unit, the pressure of refrigerant discharged from the compressor detected by the first pressure detection unit, the temperature of refrigerant taken into the compressor detected by the second temperature detection unit, the pressure of refrigerant taken into the compressor detected by the second pressure detection unit, and the aperture of the adjustment valve.

Description

[Technical field]

[0001] An embodiment of the present invention relates to a refrigeration cycle device. [Background technology]

[0002] A refrigeration cycle device is composed of a refrigerant circuit having a compressor, a condenser, an expansion valve, and an evaporator as main elements. A specific refrigerant is sealed in the refrigerant circuit. For example, when a target space is cooled or heated by the refrigeration cycle device, the refrigerant circulates through the refrigerant circuit and exchanges heat with the outside air or the inside air. In this case, if the refrigeration cycle device is not operated with an appropriate amount of refrigerant, the air conditioning capacity may not be fully exhibited, and energy saving performance and reliability may be reduced. Therefore, in order to improve the energy saving performance and reliability of the refrigeration cycle device, it is necessary to operate the refrigeration cycle device with an appropriate amount of refrigerant.

[0003] One method for determining whether the amount of refrigerant charged in the refrigerant circuit (the amount of refrigerant) is appropriate is, for example, to place an acoustic wave transmitter and receiver in the liquid pipe of the refrigerant circuit, respectively, to monitor the flow state of the refrigerant, and to determine whether the amount of refrigerant is appropriate based on the monitoring results. However, adding components for such monitoring, such as an acoustic wave element, tends to increase costs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3531440 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made based on this, and its purpose is to provide a refrigeration cycle device that can minimize cost increases due to the addition of components and determine whether the amount of refrigerant (refrigerant amount) charged to the refrigerant circuit is appropriate. [Means for solving the problem]

[0006] According to an embodiment, a refrigeration cycle device includes a refrigerant circuit, a compressor, a condenser, an evaporator, a branch passage, an expansion valve, a regulating valve, a first temperature detection unit, a first pressure detection unit, a second temperature detection unit, a second pressure detection unit, and a control unit. The refrigerant circuit includes a main flow path through which a refrigerant circulates. The compressor sucks the refrigerant from the main flow path, compresses it, and discharges the refrigerant to the main flow path. The condenser condenses the refrigerant. The evaporator evaporates the refrigerant. The branch passage is included in the refrigerant circuit, and diverts a part of the refrigerant flowing from the condenser to the evaporator from the main flow path downstream of the condenser, and injects the diverted refrigerant into the compressor. The expansion valve reduces the pressure of at least a part of the refrigerant flowing from the condenser to the evaporator downstream of the branch passage. The regulating valve adjusts the flow rate of the refrigerant flowing through the branch passage. The first temperature detection unit detects the discharge temperature of the refrigerant discharged from the compressor upstream of the condenser in the main flow path. The first pressure detection unit detects the discharge pressure of the refrigerant discharged from the compressor upstream of the condenser in the main flow path. The second temperature detection unit detects the suction temperature of the refrigerant sucked into the compressor downstream of the evaporator in the main flow path. The second pressure detection unit detects the suction pressure of the refrigerant sucked into the compressor downstream of the evaporator in the main flow path. The control unit determines whether the amount of the refrigerant charged in the refrigerant circuit is excessive or insufficient based on the relationship between the discharge temperature detected by the first temperature detection unit, the discharge pressure detected by the first pressure detection unit, the suction temperature detected by the second temperature detection unit, the suction pressure detected by the second pressure detection unit, and the opening degree of the regulating valve. The control unit determines the appropriate amount of the refrigerant to be charged, The amount of the refrigerant to be charged in the refrigerant circuit at the time of shipment is determined as an appropriate amount.The control unit holds the opening value of the regulating valve as a value of an appropriate opening value, which is set in advance under the condition that each of the discharge temperature, the discharge pressure, the suction temperature, and the suction pressure are appropriate values, and the amount of the refrigerant charged to the refrigerant circuit is the appropriate amount. When the appropriate amount is changed from the initial value in accordance with the piping length of the refrigerant circuit that has been constructed, the control unit changes and corrects the value of the appropriate opening value of the regulating valve, and holds the corrected value as the value of the appropriate opening value. When the current value of the opening value of the regulating valve at the time of determining whether the amount of the refrigerant being charged is excessive or insufficient exceeds the value of the appropriate opening value, the control unit determines that the amount of the refrigerant being charged is insufficient with respect to the appropriate amount, when the current value of the opening value is less than the value of the appropriate opening value, the control unit determines that the amount of the refrigerant being charged is excessive with respect to the appropriate amount, and when the current value of the opening value is the value of the appropriate opening value, the control unit determines that the amount of the refrigerant being charged is the appropriate amount. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a schematic configuration including a refrigeration cycle of a refrigeration cycle device according to an embodiment. [Diagram 2] FIG. 4 is a control flow diagram during a process of determining whether a refrigerant amount is appropriate in the refrigeration cycle device according to the embodiment. [Diagram 3] 3 is a Ph diagram (pressure-enthalpy diagram) in the refrigeration cycle device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a circuit diagram showing a schematic diagram of a refrigeration cycle of a refrigeration cycle device 1 according to this embodiment. The refrigeration cycle device 1 can be operated in a cooling mode or a heating mode, or in both modes, and can be used as, for example, an air conditioner, a water-cooled heat source device, an air-cooled heat pump chilling unit, a condensing unit, etc.

[0009] 1, the refrigeration cycle device 1 includes, as main elements, a compressor 11, a first temperature detection unit 12, a first pressure detection unit 13, a condenser 14, a refrigerant storage device 15, an expansion valve 16, an evaporator 17, a second pressure detection unit 18, and a second temperature detection unit 19. These components are connected by a refrigerant circuit 20 through which the refrigerant circulates, and form the refrigeration cycle unit 10. The refrigerant circuit 20 includes a main flow path 21 through which the refrigerant mainly circulates, and a branch path 22 branching off from the main flow path 21.

[0010] The compressor 11 includes, for example, a compressor body 1a and an accumulator 1b. The compressor body 1a includes, as main elements, a sealed container, a rotary compression mechanism, an electric mechanism, and the like, and compresses the gas-phase refrigerant supplied from the accumulator 1b, and discharges the high-temperature, high-pressure gas-phase refrigerant into the main flow path 21. The accumulator 1b separates the refrigerant supplied via the main flow path 21 into gas and liquid, and supplies the gas-phase refrigerant to the compressor body 1a.

[0011] The first temperature detection unit 12 detects the discharge temperature of the refrigerant discharged from the compressor 11 upstream of the condenser 14 in the main flow path 21 (hereinafter referred to as the discharge refrigerant temperature). The first temperature detection unit 12 is disposed, for example, in the vicinity of a refrigerant discharge port (not shown) of the compressor main body 1a, and detects the temperature of the gas-phase refrigerant as the discharge refrigerant temperature. The first temperature detection unit 12 is, for example, a temperature sensor (thermistor) having a temperature sensing element disposed in the piping of the main flow path 21 to detect the discharge refrigerant temperature. The operation of the first temperature detection unit 12 is controlled by the control unit 40 described later, and the detected value of the discharge refrigerant temperature is provided to the control unit 40 via wired or wireless communication.

[0012] The first pressure detection unit 13 detects the discharge pressure of the refrigerant discharged from the compressor 11 upstream of the condenser 14 in the main flow path 21 (hereinafter referred to as the discharge refrigerant pressure). The first pressure detection unit 13 is disposed, for example, in the vicinity of a refrigerant discharge port (not shown) of the compressor main body 1a, and detects the pressure of the gas phase refrigerant as the discharge refrigerant pressure. In the example shown in FIG. 1, the first pressure detection unit 13 is disposed downstream of the first temperature detection unit 12. However, the first pressure detection unit 13 may be disposed upstream of the first temperature detection unit 12. The first pressure detection unit 13 is, for example, a pressure sensor having a pressure-sensitive element disposed in the piping of the main flow path 21 to detect the discharge refrigerant pressure. The operation of the first pressure detection unit 13 is controlled by the control unit 40 described later, and the value of the detected discharge refrigerant pressure is provided to the control unit 40 via wire or wirelessly.

[0013] The condenser 14 is disposed downstream of the compressor main body 1a in the main flow path 21, and condenses the high-temperature, high-pressure gas-phase refrigerant discharged from the compressor main body 1a through heat exchange with air or the like, changing it into a high-pressure liquid-phase refrigerant.

[0014] The refrigerant storage device 15 stores excess refrigerant (hereinafter referred to as excess refrigerant) that exceeds the appropriate amount of refrigerant filled in the refrigerant circuit 20 (main flow path 21 and branch path 22). The refrigerant storage device 15 is, for example, a receiver or a liquid receiver. In the example shown in Fig. 1, the refrigerant storage device 15 is disposed downstream of the condenser 14 in the main flow path 21, and stores the high-pressure liquid-phase excess refrigerant condensed in the condenser 14. The position at which the refrigerant storage device 15 is disposed is not limited to the example shown in Fig. 1.

[0015] The expansion valve 16 reduces the pressure of the high-pressure liquid-phase refrigerant condensed in the condenser 14, and changes it to a low-pressure two-phase gas-liquid refrigerant. In the example shown in FIG. 1, the expansion valve 16 is disposed downstream of the refrigerant storage device 15 and the branch path 22 in the main flow path 21, and reduces the pressure of the high-pressure liquid-phase refrigerant condensed in the condenser 14 and flowing out of the refrigerant storage device 15, and changes it to a low-pressure two-phase gas-liquid refrigerant. At that time, the expansion valve 16 passes a part or all of the high-pressure liquid-phase refrigerant condensed in the condenser 14 and flowing out of the refrigerant storage device 15, depending on the opening degree of the adjustment valve 23. That is, the expansion valve 16 reduces the pressure of at least a part of the refrigerant flowing from the condenser 14 to the evaporator 17 downstream of the branch path 22. The expansion valve 16 is controlled by the control unit 40 described later, and the value of the opening degree is given to the control unit 40 via wired or wireless communication.

[0016] The evaporator 17 is disposed downstream of the expansion valve 16 in the main flow path 21, and evaporates the gas-liquid two-phase refrigerant that has passed through the expansion valve 16 by heat exchange with air or the like, thereby changing it into a low-temperature, low-pressure gas-phase refrigerant.

[0017] The second pressure detection unit 18 detects the suction pressure of the refrigerant sucked into the compressor 11 downstream of the evaporator 17 in the main flow path 21 (hereinafter referred to as suction refrigerant pressure). The second pressure detection unit 18 is disposed, for example, near the refrigerant suction port (not shown) of the accumulator 1b, and detects the pressure of the gas-liquid two-phase refrigerant as the suction refrigerant pressure. The second pressure detection unit 18 is, for example, a pressure sensor having a pressure-sensitive element disposed in the piping of the main flow path 21 to detect the suction refrigerant pressure. The second pressure detection unit 18 is operation-controlled by the control unit 40, which will be described later, and provides the detected value of the discharge refrigerant pressure to the control unit 40 via wired or wireless communication.

[0018] The second temperature detection unit 19 detects the suction temperature of the refrigerant sucked into the compressor 11 downstream of the evaporator 17 in the main flow path 21 (hereinafter referred to as the suction refrigerant temperature). The second temperature detection unit 19 is disposed, for example, in the vicinity of the refrigerant suction port (not shown) of the accumulator 1b, and detects the temperature of the gas-liquid two-phase refrigerant as the suction refrigerant temperature. In the example shown in FIG. 1, the second temperature detection unit 19 is disposed downstream of the second pressure detection unit 18. However, the second temperature detection unit 19 may be disposed upstream of the second pressure detection unit 18. The second temperature detection unit 19 is, for example, a temperature sensor (thermistor) having a temperature sensing element disposed in the piping of the main flow path 21 to detect the suction refrigerant temperature. The second temperature detection unit 19 is controlled by the control unit 40 described later, and provides the detected value of the suction refrigerant temperature to the control unit 40 via wired or wireless communication.

[0019] As shown in Fig. 1, the main flow path 21 is branched by a branch path 22 between the condenser 14 and the expansion valve 16, specifically between the refrigerant storage device 15 and the expansion valve 16, and is bypassed to the compressor body 1a of the compressor 11 via the branch path 22. The branch path 22 is a bypass flow path of the main flow path 21. The branch path 22 diverts a part of the refrigerant flowing from the condenser 14 to the evaporator 17 from the main flow path 21. In the example shown in Fig. 1, the branch path 22 diverts a part of the high-pressure liquid-phase refrigerant that has been condensed in the condenser 14 and flowed out of the refrigerant storage device 15 downstream of the refrigerant storage device 15 and upstream of the expansion valve 16.

[0020] An adjustment valve 23 is disposed in the branch path 22. The adjustment valve 23 reduces the pressure of the high-pressure liquid-phase refrigerant flowing through the branch path 22, changing it to a low-pressure gas-liquid two-phase refrigerant. The adjustment valve 23 also adjusts the flow rate of the refrigerant flowing through the branch path 22 according to its opening degree. The operation of the adjustment valve 23 is controlled by a control unit 40, which will be described later, and the value of the opening degree is provided to the control unit 40 via wired or wireless communication. The adjustment valve 23 is adjusted to an appropriate opening degree (hereinafter referred to as an appropriate opening degree) based on, for example, the discharged refrigerant temperature.

[0021] In the present embodiment, as an example, the appropriate opening is specified as a value of the opening of the regulating valve 23 that is set in advance under a predetermined condition. The predetermined condition (hereinafter referred to as a prerequisite) here is that the discharge refrigerant temperature, the discharge refrigerant pressure, the suction refrigerant temperature, and the suction refrigerant pressure are each an appropriate value, and the refrigerant is charged into the refrigerant circuit 20 at an appropriate amount (an optimal amount to be described later) and the refrigeration cycle device 1 is operated. By adjusting the opening of the regulating valve 23 to the appropriate opening, the flow rate of the refrigerant in the branch passage 22 (hereinafter referred to as an injection flow rate) is adjusted to an appropriate amount. That is, the appropriate opening is specified in advance so that the injection flow rate becomes an appropriate amount under the predetermined condition. The value of the appropriate opening is, for example, linked to the value of the optimal amount of refrigerant to be described later and made into a table, and is held in the storage device of the control unit 40, and is appropriately read into the memory as a parameter during operation of the refrigeration cycle device 1. As a result, the opening of the regulating valve 23 is adjusted to the appropriate opening, and the injection flow rate is adjusted to an appropriate amount.

[0022] The branch passage 22 injects the low-pressure gas-liquid two-phase refrigerant that has passed through the regulating valve 23 into the compressor body 1a. That is, the branch passage 22 is a so-called injection flow path. By injecting the gas-liquid two-phase refrigerant into the compressor body 1a, the compressor body 1a is cooled, and the temperature of the refrigerant discharged from the compressor body 1a (in short, the discharge refrigerant temperature) decreases.

[0023] In addition to these components, the refrigeration cycle apparatus 1 includes a notification unit 30 and a control unit 40.

[0024] The notification unit 30 is operatively controlled by the control unit 40, and notifies that the amount of refrigerant charged in the refrigeration cycle apparatus 1 (hereinafter referred to as the refrigerant amount) is not an appropriate amount. The refrigerant amount is the amount of refrigerant charged in the refrigerant circuit 20, and more specifically, the current amount of refrigerant charged in the pipes constituting the refrigerant circuit 20 (main flow path 21 and branch path 22). The appropriate amount of refrigerant is the appropriate amount of refrigerant that should be charged in the refrigerant circuit 20, and is set in advance as the amount required to operate the refrigeration cycle apparatus 1 and achieve desired air conditioning performance under conditions such as the expected pipe lengths of the main flow path 21 and branch path 22.

[0025] The expected piping lengths of the main flow path 21 and the branch path 22 vary depending on conditions such as the environment in which the refrigeration cycle device 1 is installed. For this reason, the appropriate amount of refrigerant can be set to multiple values, for example, at the time of shipment from the factory, depending on such conditions. In this case, an optimal value is selected from multiple appropriate amounts set in advance depending on the piping length after the installation of the refrigeration cycle device 1 is completed, that is, the piping length actually constructed. Such a selection may be made manually or automatically by the control unit 40. The selected appropriate amount (hereinafter referred to as the optimal amount) is held, for example, in a storage device of the control unit 40 described later, and is appropriately read out to the memory as a parameter.

[0026] For example, when the amount of refrigerant is less than the optimum amount, the notification unit 30 issues a predetermined notification that the amount of refrigerant is insufficient relative to the optimum amount. In this case, there is a risk of refrigerant leaking from the piping of the main flow path 21 or the branch path 22. Therefore, the notification unit 30 notifies the user that the refrigeration cycle apparatus 1 is not operating properly and that an abnormal state in which desired air conditioning cannot be achieved is occurring. This thoroughly informs and draws the attention of users, workers, etc. (hereinafter, referred to as users, etc.) that the refrigeration cycle apparatus 1 needs to be temporarily stopped for inspection work, for example.

[0027] Furthermore, when the amount of refrigerant exceeds the optimum amount, the notification unit 30 may issue a predetermined notification that the amount of refrigerant is excessive with respect to the optimum amount. In this case, since the surplus refrigerant can be stored in the refrigerant storage device 15, it does not immediately impede proper operation of the refrigeration cycle device 1. However, by notifying that the amount of refrigerant is excessive with respect to the optimum amount, it is possible to call the attention of the user, etc. In addition, when the amount of refrigerant is the optimum amount, the amount of refrigerant is in a normal state with no excess or shortage, and the notification unit 30 may notify that the refrigeration cycle device 1 can continue to operate properly.

[0028] The notification unit 30 may be an indicator light, a monitor, a panel, a speaker, or a combination of these. For example, when the amount of refrigerant is insufficient relative to the optimal amount, the notification unit 30 will turn on (blink) the indicator light red, sound an alarm, play or display an alarm message, or irradiate a laser, to thoroughly inform users, workers, etc. (hereinafter, referred to as users, etc.) of the refrigerant leakage and to call their attention. On the other hand, when the amount of refrigerant is excessive relative to the optimal amount, the notification unit 30 may only provide a minimum notification, such as turning on the indicator light yellow or blue, or displaying a confirmation message. Note that when the amount of refrigerant is equal to or greater than the optimal amount, or when the amount of refrigerant is the optimal amount, the notification unit 30 need not provide any notification.

[0029] The notification unit 30 may be located anywhere as long as it can properly notify and alert users, etc. For example, the notification unit 30 may be provided in a central control room of the refrigeration cycle apparatus 1 or on a remote controller for operation.

[0030] The control unit 40 controls the operation of the refrigeration cycle device 1. In this embodiment, the control unit 40 controls the operation of the compressor 11, the first temperature detection unit 12, the first pressure detection unit 13, the refrigerant storage device 15, the expansion valve 16, the second pressure detection unit 18, the second temperature detection unit 19, the adjustment valve 23, and the notification unit 30 in the refrigeration cycle unit 10. For example, the control unit 40 controls the start and stop, rotation speed, frequency, etc. of the compressor 11, and adjusts the opening of the expansion valve 16 and the adjustment valve 23 during such control. In addition, in controlling the operation of the refrigeration cycle device 1, the control unit 40 judges whether the amount of refrigerant charged in the refrigerant circuit 20 is excessive or insufficient, that is, judges whether the amount of refrigerant is appropriate, as described later, based on the relationship between the discharge refrigerant temperature, the discharge refrigerant pressure, the suction refrigerant temperature, the suction refrigerant pressure, and the opening of the adjustment valve 23.

[0031] The control unit 40 includes a CPU, a memory, a storage device (non-volatile memory), an input / output circuit, a timer, and the like, and executes a predetermined calculation process. For example, the control unit 40 reads various data by the input / output circuit, performs calculation process by the CPU using a program read from the storage device to the memory, and controls the operation of the compressor 11, the first temperature detection unit 12, the first pressure detection unit 13, the refrigerant storage device 15, the expansion valve 16, the second pressure detection unit 18, the second temperature detection unit 19, the adjustment valve 23, and the notification unit 30 based on the processing result. At that time, the control unit 40 transmits and receives control signals and data signals between them via wire or wirelessly. That is, the control unit 40 and each of the components to be controlled are electrically connected via wire or wirelessly.

[0032] In the refrigeration cycle apparatus 1 having the above-mentioned configuration, the operation control of the refrigeration cycle apparatus 1 performed by the control unit 40, specifically, the control for determining whether the amount of refrigerant in the refrigerant circuit 20 is excessive or insufficient when controlling the operation of the refrigeration cycle apparatus 1 (hereinafter, referred to as refrigerant amount suitability determination process) will be described according to the control flow of the control unit 40. Fig. 2 shows the control flow of the control unit 40 during the refrigerant amount suitability determination process.

[0033] In the refrigerant amount suitability determination process, the refrigeration cycle apparatus 1 starts operation (S101). Specifically, the control unit 40 starts the compressor 11 and opens the expansion valve 16 to circulate the refrigerant in the main flow path 21. At that time, the control unit 40 adjusts the regulating valve 23 to an appropriate opening degree, assuming that the above-mentioned prerequisites are met, and adjusts the flow rate of the refrigerant in the branch path 22 (injection flow rate) to an appropriate amount. That is, it is assumed that at the start of operation, the refrigeration cycle apparatus 1 is operating in a state where the regulating valve 23 is adjusted to an appropriate opening degree so that the injection flow rate is an appropriate amount. The operation of the refrigeration cycle apparatus 1 in this state is used as a trigger to enable the control unit 40 to execute the refrigerant amount suitability determination process.

[0034] While the refrigeration cycle apparatus 1 is operating in this manner, the control unit 40 acquires each value (operation data) indicating the operating state of the refrigeration cycle apparatus 1 (S102). The operating data here is the discharge refrigerant temperature, the discharge refrigerant pressure, the suction refrigerant temperature, the suction refrigerant pressure, and the opening degree of the regulating valve 23. Therefore, the control unit 40 acquires these operating data from the first temperature detection unit 12, the first pressure detection unit 13, the second temperature detection unit 19, the second pressure detection unit 18, and the regulating valve 23, respectively.

[0035] Next, the control unit 40 judges whether the amount of refrigerant in the refrigerant circuit 20 is appropriate based on the acquired operation data (S103). That is, the control unit 40 judges whether the amount of refrigerant is appropriate based on the relationship between the discharge refrigerant temperature, the discharge refrigerant pressure, the suction refrigerant temperature, the suction refrigerant pressure, and the opening degree of the regulating valve 23. For example, when the discharge refrigerant temperature, the discharge refrigerant pressure, the suction refrigerant temperature, and the suction refrigerant pressure are all predetermined values ​​(appropriate values ​​in the prerequisite), the control unit 40 judges whether the amount of refrigerant is appropriate based on the relationship between the opening degree of the regulating valve 23 and the appropriate opening degree. In this embodiment, the refrigeration cycle device 1 holds in advance, for example, at the time of shipment from the factory, the values ​​of the discharge refrigerant temperature, the discharge refrigerant pressure, the suction refrigerant temperature, and the suction refrigerant pressure when the refrigerant is charged in a plurality of appropriate amounts and the appropriate opening degree of the regulating valve 23 when the refrigerant is operated. These values ​​are, for example, linked to the plurality of appropriate amounts of refrigerant, respectively, in a table, and are held in the storage device of the control unit 40. Note that instead of such values, they may be held in a table as a numerical range, and held in the storage device of the control unit 40.

[0036] Furthermore, the value of the appropriate opening degree of the regulating valve 23 can be changed according to the situation after the start of actual operation of the refrigeration cycle apparatus 1, for example, fluctuations in the amount of refrigerant (the current amount of charged refrigerant), even after the value is stored in the storage device of the control unit 40. As described above, the appropriate amount of refrigerant may be changed from a preset initial value according to conditions such as the environment in which the refrigeration cycle apparatus 1 is installed, for example, the piping lengths of the main flow path 21 and the branch path 22 that are actually constructed. That is, the control unit 40 stores the appropriate amount of refrigerant so that it can be changed from the initial value.

[0037] Therefore, the optimal amount of refrigerant (a value selected from a plurality of appropriate amounts) may be set by changing the initial value of the appropriate amount to a value calculated when the refrigeration cycle device 1 is installed, and may be stored in the storage device of the control unit 40. In anticipation of such a case, the value of the appropriate opening of the regulating valve 23 may be made changeable, thereby improving the accuracy of the judgment of whether the amount of refrigerant is appropriate. That is, when the appropriate amount of refrigerant, in short, the optimal amount, is changed from the initial value, the control unit 40 is capable of changing and correcting the value of the appropriate opening of the regulating valve 23, and storing the corrected value. For example, in a multi-air conditioner for a building, the additional charge amount for the appropriate amount of refrigerant is calculated based on the length of the connecting pipe, and even when the refrigerant is additionally charged at the installation site, or when the appropriate refrigerant is charged in the refrigerant circuit after installation, as in a refrigerator, it is possible to appropriately respond to such cases.

[0038] When determining whether the amount of refrigerant is appropriate, the control unit 40 compares the acquired value of the opening of the regulating valve 23, that is, the current value of the opening of the regulating valve 23, with the value of the appropriate opening. The value of the appropriate opening is read, for example, from a storage device of the control unit 40 to a memory. For example, if the value of the opening of the regulating valve 23 exceeds the value of the appropriate opening, the control unit 40 determines that the amount of refrigerant is not appropriate, specifically that the amount of refrigerant is less than the optimal amount (the amount of refrigerant is insufficient relative to the optimal amount, or in short, the appropriate amount). On the other hand, if the value of the opening of the regulating valve 23 is less than the value of the appropriate opening, the control unit 40 determines that the amount of refrigerant is not appropriate, specifically that the amount of refrigerant exceeds the optimal amount (the amount of refrigerant is excessive relative to the optimal amount, or in short, the appropriate amount). Then, if the amount of refrigerant is the optimal amount, or in short, the appropriate amount, the control unit 40 determines that the amount of refrigerant is appropriate, without being excessive or insufficient.

[0039] Such a determination is possible for the following reasons. FIG. 3 shows a Ph diagram (pressure-enthalpy diagram) in the refrigeration cycle device 1 according to this embodiment. In FIG. 3, M is the amount of refrigerant flowing through the evaporator 17. Also, m is the injection flow rate, and the subscript 1 (m1) indicates the injection flow rate (m1) when the amount of refrigerant is optimal, and the subscript 2 indicates the injection flow rate (m2) when the amount of refrigerant is insufficient relative to the optimal amount. Similarly, in FIG. 3, SC1 indicates the degree of supercooling at the outlet of the condenser 14 when the amount of refrigerant is optimal. SC2 indicates the degree of supercooling at the outlet of the condenser 14 when the amount of refrigerant is insufficient relative to the optimal amount. h1, h2, h3, and h4 indicate the enthalpy at each state point. Tsuc indicates the suction refrigerant temperature, and Td indicates the discharge refrigerant temperature.

[0040] When the amount of refrigerant is optimal, in other words, when the degree of subcooling at the outlet of the condenser 14 is SC1, the injection flow rate (m1) is calculated by the relational expression m1=M(h4-h3) / (h3-h1). On the other hand, when the amount of refrigerant is insufficient for the optimal amount, in other words, when the degree of subcooling at the outlet of the condenser 14 is SC2, the injection flow rate (m2) is calculated by the relational expression m2=M(h4-h3) / (h3-h2). As shown in FIG. 3, since SC2 is smaller than SC1, (h3-h1)>(h3-h2). Therefore, when the amount of refrigerant is insufficient for the optimal amount, the injection flow rate (m2) is larger than the injection flow rate (m1) when the amount of refrigerant is optimal. As a result, when the amount of refrigerant is insufficient for the optimal amount, the opening degree of the regulating valve 23 in the injection flow passage 22 is larger than the opening degree (proper opening degree) of the regulating valve 23 when the amount of refrigerant is optimal.

[0041] Therefore, when the opening value of the regulating valve 23 is not the appropriate opening value, it can be determined that the amount of refrigerant is not the optimal amount. For example, when the opening value of the regulating valve 23 exceeds the appropriate opening value, it can be determined that the amount of refrigerant does not reach the optimal amount (the amount of refrigerant is insufficient with respect to the optimal amount). When the opening value of the regulating valve 23 is less than the appropriate opening value, it can be determined that the amount of refrigerant exceeds the optimal amount (the amount of refrigerant is excessive with respect to the optimal amount). When the opening value of the regulating valve 23 is the appropriate opening, it can be determined that the amount of refrigerant is the optimal amount, that is, the amount of refrigerant is neither too much nor too little and is appropriate.

[0042] If it is determined in S103 that the amount of refrigerant is not optimal (Yes in S104 or S106), the control unit 40 operates the notification unit 30 to provide the desired notification that the amount of refrigerant is not optimal, as follows.

[0043] When it is determined that the amount of refrigerant is less than the optimum amount, that is, the amount of refrigerant is insufficient relative to the optimum amount (Yes in S104), the control unit 40 causes the notification unit 30 to notify that the refrigeration cycle apparatus 1 is not operating properly and that an abnormal state in which desired air conditioning cannot be achieved is occurring (S105). For example, the control unit 40 operates the notification unit 30 to turn on (blink) an indicator light in red, sound an alarm, play or display an alarm message, irradiate a laser, etc. This makes it possible to thoroughly inform users of the refrigerant leakage and to call their attention.

[0044] Furthermore, if it is determined that the amount of refrigerant exceeds the optimum amount, that is, that the amount of refrigerant is excessive relative to the optimum amount (No in S104 and Yes in S106), the control unit 40 causes the surplus refrigerant to be stored in the refrigerant storage device 15 (S107). That is, the control unit 40 operates the refrigerant storage device 15 to start storing the surplus refrigerant. As a result, the surplus refrigerant is stored in the refrigerant storage device 15, and the amount of refrigerant is adjusted to the optimum amount. Therefore, the refrigeration cycle apparatus 1 can be operated appropriately continuously to perform the desired air conditioning.

[0045] Additionally, the control unit 40 causes the notification unit 30 to give a notification to alert the user or the like (S108). For example, the control unit 40 operates the notification unit 30 to light up the indicator lamp yellow, display a confirmation message, or the like. Although it is sufficient to keep the notification to a minimum in this manner, in this case, the control unit 40 does not need to operate the notification unit 30 and does not need to give any notification. Even if no notification is given, the excess refrigerant is stored in the refrigerant storage device 15 (S107), so that a situation that immediately impedes proper operation of the refrigeration cycle apparatus 1 can be avoided.

[0046] When the notification unit 30 is caused to give a desired notification (S105 or S108), the control unit 40 judges the operation stop condition of the refrigeration cycle apparatus 1 (S109). When it is determined in S103 that the amount of refrigerant is the optimum amount (No in S104 and No in S106), the control unit 40 judges the operation stop condition of the refrigeration cycle apparatus 1 (S109). In this case, the control unit 40 may, for example, cause the notification unit 30 to notify that the amount of refrigerant is the optimum amount before determining the operation stop condition. The operation stop condition is a judgment condition for whether or not to stop the operation of the refrigeration cycle apparatus 1, and is judged, for example, depending on whether or not the control unit 40 has received a signal indicating the operation stop of the refrigeration cycle apparatus 1. The signal indicating the operation stop is transmitted when the operation stop is selected from, for example, a centralized control room or an operation remote control of the refrigeration cycle apparatus 1.

[0047] If the operation stop condition is not satisfied, the control unit 40 acquires operation data of the refrigeration cycle device 1 (S102), and again determines whether the amount of refrigerant in the refrigerant circuit 20 is appropriate based on the acquired operation data (S103). Then, the control unit 40 selectively repeats the subsequent processes (S104 to S108) depending on the determination result. On the other hand, when the operation stop condition is met, the control unit 40 stops the operation of the refrigeration cycle apparatus 1 (S110).

[0048] That is, a series of processes for determining whether the refrigerant amount is appropriate is repeated while the refrigeration cycle apparatus 1 is operating. Then, when the operation of the refrigeration cycle apparatus 1 is stopped, the series of processes for determining whether the refrigerant amount is appropriate is also terminated.

[0049] As described above, according to the present embodiment, the first temperature detection unit 12, the first pressure detection unit 13, the second temperature detection unit 19, the second pressure detection unit 18, and the regulating valve 23 can be used to determine whether the amount of refrigerant charged into the refrigerant circuit 20 (the amount of refrigerant) is appropriate. These components can be those that the refrigeration cycle device 1 has conventionally been equipped with. Therefore, it is not necessary to add a dedicated member for performing the refrigerant amount appropriateness determination process, such as a sound wave transmitting element and receiving element. In other words, it is possible to minimize the increase in cost due to the addition of members and to determine whether the amount of refrigerant charged into the refrigerant circuit 20 (the amount of refrigerant) is appropriate. This makes it possible to suppress the excess or deficiency of the amount of refrigerant in the refrigerant circuit 20. Therefore, the refrigeration cycle device 1 can be operated appropriately to exhibit the desired air conditioning performance, and the energy saving and reliability of the refrigeration cycle device 1 can be improved.

[0050] In addition, by issuing a desired notification when the amount of refrigerant in the refrigerant circuit 20 is excessive or insufficient, it is possible to thoroughly inform and alert users as to whether the amount of refrigerant is appropriate. For example, when the amount of refrigerant is insufficient relative to the optimum amount, the refrigeration cycle device 1 can be quickly stopped for inspection work. This makes it possible to immediately perform work such as repairing or replacing the main flow path 21 or the branch path (injection flow path) 22, or refilling the refrigerant, and quickly restore the refrigeration cycle device 1 to proper operation. Also, by issuing a desired notification when the amount of refrigerant is excessive relative to the optimum amount, or when the amount of refrigerant is the optimum amount, it is possible to prevent, for example, the refrigeration cycle device 1 from operating improperly and reaching an abnormal state in which desired air conditioning cannot be achieved.

[0051] Furthermore, by making it possible to change the appropriate opening value of the adjustment valve 23 according to the operating conditions of the refrigeration cycle device 1 after installation, it is possible to more appropriately suppress surplus or deficiency of the amount of refrigerant in the refrigerant circuit 20, and further prevent a decrease in the energy efficiency and reliability of the refrigeration cycle device 1.

[0052] In the above-described embodiment, the refrigeration cycle device 1 includes a first pressure detection unit 13 for detecting the discharge refrigerant pressure and a second pressure detection unit 18 for detecting the suction refrigerant pressure. However, instead of the pressure detection units 13 and 18, the discharge refrigerant pressure and the suction refrigerant pressure may be calculated based on a method of converting the refrigerant condensation temperature or evaporation temperature into a saturated vapor pressure, or a method of converting from the relationship between the outside air temperature and the condenser fan rotation speed and the evaporator fan rotation speed and the outside air temperature. In this case, the pressure detection units 13 and 18 can be omitted, and the increase in cost due to the addition of members can be further suppressed.

[0053] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0054] DESCRIPTION OF SYMBOLS 1... refrigeration cycle device, 1a... compressor main body, 1b... accumulator, 10... refrigeration cycle section, 11... compressor, 12... first temperature detection section, 13... first pressure detection section, 14... condenser, 15... refrigerant storage device, 16... expansion valve, 17... evaporator, 18... second pressure detection section, 19... second temperature detection section, 20... refrigerant circuit, 21... main flow path, 22... branch path (injection flow path), 23... adjustment valve, 30... notification section, 40... control section.

Claims

1. a refrigerant circuit including a main flow path through which a refrigerant circulates; a compressor that draws in the refrigerant from the main flow path, compresses it, and discharges the refrigerant to the main flow path; a condenser for condensing the refrigerant; an evaporator for evaporating the refrigerant; a branch passage included in the refrigerant circuit, which branches a portion of the refrigerant flowing from the condenser to the evaporator from the main flow passage downstream of the condenser and injects the branched refrigerant into the compressor; an expansion valve that reduces the pressure of at least a portion of the refrigerant flowing from the condenser to the evaporator downstream of the branch path; an adjustment valve for adjusting a flow rate of the refrigerant flowing through the branch path; a first temperature detection unit that detects a discharge temperature of the refrigerant discharged from the compressor upstream of the condenser in the main flow path; a first pressure detection unit that detects a discharge pressure of the refrigerant discharged from the compressor upstream of the condenser in the main flow path; a second temperature detection unit that detects a suction temperature of the refrigerant sucked into the compressor downstream of the evaporator in the main flow path; a second pressure detection unit that detects a suction pressure of the refrigerant sucked into the compressor downstream of the evaporator in the main flow path; a control unit that determines whether an amount of the refrigerant charged in the refrigerant circuit is excessive or insufficient based on a relationship between the discharge temperature detected by the first temperature detection unit, the discharge pressure detected by the first pressure detection unit, the suction temperature detected by the second temperature detection unit, the suction pressure detected by the second pressure detection unit, and an opening degree of the regulating valve, The control unit is The appropriate amount of the refrigerant to be charged is changed from an initial value preset at the time of shipment as an appropriate amount of the refrigerant to be charged in the refrigerant circuit in accordance with a piping length of the constructed refrigerant circuit; a value of the opening degree of the regulating valve that is preset under conditions in which the discharge temperature, the discharge pressure, the suction temperature, and the suction pressure are all appropriate values, and the amount of the refrigerant charged in the refrigerant circuit is the appropriate amount, is maintained as a value of an appropriate opening degree; When the appropriate amount is changed from the initial value according to the installed piping length of the refrigerant circuit, the value of the appropriate opening of the regulating valve is changed and corrected, and the corrected value is held as the value of the appropriate opening; When the current value of the opening of the regulating valve at the time of judging whether the amount of refrigerant charged is excessive or insufficient exceeds the appropriate opening value, it is judged that the amount of refrigerant charged is insufficient with respect to the appropriate amount, when the current value of the opening is less than the appropriate opening value, it is judged that the amount of refrigerant charged is excessive with respect to the appropriate amount, and when the current value of the opening is the appropriate opening value, it is judged that the amount of refrigerant charged is the appropriate amount. Refrigeration cycle equipment.

2. The cooling system further includes a notification unit that notifies the user that the amount of the refrigerant charged is not the appropriate amount. When the control unit determines that the amount of the refrigerant charged is not the appropriate amount, the control unit operates the notification unit to notify that the amount of the refrigerant charged is not the appropriate amount. The refrigeration cycle device according to claim 1.

3. The cooling device further includes a cooling medium storage device that stores an excess amount of the cooling medium that exceeds the appropriate amount when the amount of the cooling medium charged is excessive with respect to the appropriate amount, When the control unit determines that the amount of the refrigerant being charged is insufficient with respect to the appropriate amount, the control unit notifies the notification unit of the determination result, and when the control unit determines that the amount of the refrigerant being charged is excessive with respect to the appropriate amount, the control unit causes the notification unit to store the excess refrigerant in the refrigerant storage device. The refrigeration cycle device according to claim 2.

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