WO2020031319A1

WO2020031319A1 - Refrigeration cycle device

Info

Publication number: WO2020031319A1
Application number: PCT/JP2018/029871
Authority: WO
Inventors: 悟梁池; 野本　宗; 肇藤本; 池田　隆; 佐多　裕士; 昌彦中川; 七種　哲二; 悠介有井; 洋貴佐藤; 亮築山
Original assignee: 三菱電機株式会社
Priority date: 2018-08-09
Filing date: 2018-08-09
Publication date: 2020-02-13
Also published as: JPWO2020031319A1; JP7002660B2; CN112513541A; CN112513541B

Abstract

A non-azeotropic mixed refrigerant that has a specific composition ratio is circulated in a refrigeration cycle device (100) according to the present invention. This refrigeration cycle device (100) is provided with a compressor (1), a first heat exchanger (2), a refrigerant container (3), a pressure reduction unit (4) and a second heat exchanger (5). The non-azeotropic mixed refrigerant is sequentially circulated through the compressor (1), the first heat exchanger (2), the refrigerant container (3), the pressure reduction unit (4) and the second heat exchanger (5) in this order. The drive frequency (fc) of the compressor (1) in a first case is higher than the drive frequency (fc) of the compressor (1) in a second case. In the first case, the difference between the reference temperature and a first temperature (T1) of the non-azeotropic mixed refrigerant at a specific pressure (Ps) is larger than a first threshold. In the second case, the difference between the reference temperature and the first temperature (T1) is smaller than the first threshold. The specific pressure (Ps) is the pressure of the non-azeotropic mixed refrigerant flowing out from the pressure reduction unit (4).

Description

Refrigeration cycle device

The present invention relates to a refrigeration cycle device in which a non-azeotropic mixed refrigerant circulates.

Conventionally, a refrigeration cycle device in which a non-azeotropic mixed refrigerant circulates is known. For example, JP-A-6-101912 (Patent Document 1) discloses a refrigeration cycle apparatus including a refrigerant composition sensor that detects the composition of a non-azeotropic mixed refrigerant. According to the refrigeration cycle apparatus, since the control target is changed according to the composition of the circulating non-azeotropic refrigerant mixture, stable operation can be performed even when the composition of the non-azeotropic refrigerant mixture changes.

JP-A-6-101912

Patent Document 1 discloses the configuration of a refrigerant composition sensor that detects the composition of a non-azeotropic refrigerant mixture in which HFC32 and HFC134a are mixed. However, in a refrigeration cycle apparatus in which a non-azeotropic mixed refrigerant including three or more types of refrigerant circulates, it is difficult to detect the composition of the non-azeotropic mixed refrigerant by the refrigerant composition sensor. According to the refrigeration cycle apparatus disclosed in Patent Literature 1, it may be difficult to suppress performance degradation of the refrigeration cycle apparatus depending on the number of refrigerants contained in the non-azeotropic mixed refrigerant.

The present invention has been made to solve the above-described problems, and an object of the present invention is to suppress a decrease in performance of a refrigeration cycle apparatus regardless of the number of refrigerants contained in a non-azeotropic mixed refrigerant. is there.

非 In the refrigeration cycle device according to the present invention, a non-azeotropic mixed refrigerant having a specific composition ratio circulates. The refrigeration cycle device includes a compressor, a first heat exchanger, a refrigerant container, a decompression unit, and a second heat exchanger. The non-azeotropic mixed refrigerant circulates in the order of the compressor, the first heat exchanger, the refrigerant container, the pressure reducing unit, and the second heat exchanger. The driving frequency of the compressor in the first case is higher than the driving frequency of the compressor in the second case. In the first case, the difference between the first temperature of the non-azeotropic mixed refrigerant at the specific pressure and the reference temperature is larger than the first threshold. In the second case, the difference between the first temperature and the reference temperature is smaller than the first threshold. The specific pressure is the pressure of the non-azeotropic refrigerant mixture flowing out of the pressure reducing unit.

According to the refrigeration cycle apparatus according to the present invention, the driving frequency of the compressor in the first case is reduced by the compression frequency in the second case with respect to the temperature of the non-azeotropic mixed refrigerant at the pressure of the non-azeotropic mixed refrigerant flowing out of the pressure reducing section. By making the driving frequency higher than the driving frequency of the chiller, the change in the composition ratio of the non-azeotropic mixed refrigerant is reflected on the control of the refrigeration cycle apparatus. As a result, regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant, it is possible to suppress a decrease in performance of the refrigeration cycle device.

FIG. 2 is a functional block diagram illustrating a configuration of a refrigeration cycle device according to Embodiment 1. It is a figure which shows the relationship between the amount of gas refrigerant in a receiver, and circulating composition ratio when R463A is used as a non-azeotropic mixed refrigerant. FIG. 3 is a Mollier diagram showing a relationship among pressure, enthalpy, and temperature of a non-azeotropic mixed refrigerant. 2 is a flowchart illustrating a flow of a drive frequency correction process performed by the control device of FIG. 1. It is a figure which also shows the temperature of the non-azeotropic mixed refrigerant according to the position between the inflow port and the outflow port of the evaporator, and the temperature of the air which exchanges heat with the non-azeotropic mixed refrigerant at the position. It is a figure which shows together the relationship between the gas refrigerant amount in a receiver, and the temperature detected by a temperature sensor, and the relationship between the gas refrigerant amount in a receiver, and the average temperature of saturated liquid and saturated vapor in suction pressure. 6 is a flowchart illustrating a flow of a drive frequency correction process performed by the control device of the refrigeration cycle device according to the modification of the first embodiment. FIG. 5 is a functional block diagram illustrating a configuration of a refrigeration cycle device according to a second modification of the first embodiment. 9 is a flowchart illustrating a flow of a drive frequency correction process performed by the control device of the refrigeration cycle device according to the third modification of the first embodiment. 9 is a flowchart showing a flow of processing performed at the time of starting operation of the refrigeration cycle apparatus according to Embodiment 2. FIG. 13 is a functional block diagram illustrating a configuration of a refrigeration cycle device according to Embodiment 3. It is a flowchart which shows the flow of the alerting | reporting process of the refrigerant | coolant shortage performed by the control apparatus of FIG. FIG. 9 is a diagram illustrating a configuration of a refrigeration cycle device according to Embodiment 4. 14 is a flowchart showing a flow of a refrigerant shortage notification process performed by the control device of FIG. 13. 17 is a flowchart illustrating a flow of a process of determining whether or not additional charging is possible, which is performed by the control device of the refrigeration cycle apparatus according to Embodiment 5. FIG. 14 is a functional block diagram illustrating a configuration of a refrigeration cycle device according to Embodiment 6. FIG. 3 is a Mollier diagram showing a relationship among pressure, enthalpy, and temperature of a non-azeotropic mixed refrigerant. 17 is a flowchart showing a flow of a drive frequency correction process performed by the control device of FIG. 16.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated in principle.

Embodiment 1 FIG.
FIG. 1 is a functional block diagram illustrating a configuration of a refrigeration cycle apparatus 100 according to Embodiment 1. As shown in FIG. 1, the refrigeration cycle apparatus 100 includes a compressor 1, a condenser 2 (first heat exchanger), a receiver 3 (refrigerant container), a decompression unit 4, and an evaporator 5 (second A heat exchanger), a control device 10, a temperature sensor 101, and

pressure sensors

102 and 103. The pressure reducing unit 4 includes an expansion valve 41 (first pressure reducing device) and a capillary tube 42 (second pressure reducing device).

In the refrigeration cycle apparatus 100, the non-azeotropic mixed refrigerant (for example, R463A) circulates in the order of the compressor 1, the condenser 2, the receiver 3, the expansion valve 41, and the evaporator 5, and the compressor 1, the condenser 2, It circulates in the order of the receiver 3 and the capillary tube 42.

The temperature sensor 101 measures the temperature T1 (first temperature) of the non-azeotropic refrigerant mixture flowing out of the capillary tube 42. The pressure sensor 102 detects a pressure Ps (specific pressure) of the non-azeotropic mixed refrigerant sucked into the compressor 1. The pressure sensor 103 detects the pressure Pd of the non-azeotropic refrigerant mixture discharged from the compressor 1.

The control device 10 controls the amount of non-azeotropic mixed refrigerant discharged from the compressor 1 per unit time by controlling the drive frequency fc of the compressor 1. Control device 10 receives temperature T2 and pressures Ps and Pd from temperature sensor 101 and

pressure sensors

102 and 103, respectively. The control device 10 includes a storage unit 11. The storage unit 11 stores, for example, physical property values of the non-azeotropic refrigerant mixture and control target values of specific parameters (for example, the evaporation temperature or the condensation temperature) in advance.

(4) The receiver 3 stores a liquid non-azeotropic mixed refrigerant and vaporizes a refrigerant (low-boiling refrigerant) having a relatively lower boiling point than other refrigerants among the refrigerants contained in the non-azeotropic mixed refrigerant. As the non-azeotropic mixed refrigerant circulates through the refrigeration cycle apparatus 100, the amount of gaseous refrigerant (gas refrigerant) contained in the receiver 3 increases. Since the low boiling point refrigerant contained in the non-azeotropic mixed refrigerant circulating in the refrigeration cycle apparatus 100 decreases, the composition ratio (circulation composition ratio) of the non-azeotropic mixed refrigerant circulating in the refrigeration cycle apparatus 100 changes.

FIG. 2 is a diagram showing the relationship between the amount of gas refrigerant in the receiver 3 and the circulating composition ratio when R463A is used as the non-azeotropic mixed refrigerant. In FIG. 2, the gas refrigerant amount in the receiver 3 on the horizontal axis is expressed as a ratio of the gas refrigerant amount in the receiver 3 to the initial refrigerant amount (the amount of the non-azeotropic mixed refrigerant sealed in the refrigeration cycle device 100). I have. The same applies to FIG.

@ R463A includes R32, R125, R1234yf, R134a, and CO2 in a 36: 30: 14: 14: 6 weight percent (wt%) ratio. R463A contains CO2 to secure the refrigerant pressure. The boiling points of R32, R125, R1234yf, R134a, and CO2 at one atmosphere are -51.7 ° C, -48.1 ° C, -29.4 ° C, -26.1 ° C, and -78.5 ° C. It is. CO2 has the lowest boiling point among the refrigerants contained in R463A. Note that the non-azeotropic mixed refrigerant circulating in the refrigeration cycle apparatus 100 is not limited to R463A.

As shown in FIG. 2, when the gas refrigerant amount in the receiver 3 is 0, the circulation composition ratio of R32, R125, R1234yf, R134a, and CO2 is equal to the composition ratio (initial value) of R463A. As the amount of gas refrigerant in the receiver 3 increases, the circulating composition ratio of CO2 and R32 decreases. On the other hand, the circulating composition ratio of R125, R1234yf, and R134a increases.

FIG. 3 is a Mollier chart showing the relationship among the pressure, enthalpy, and temperature of the non-azeotropic refrigerant mixture. In FIG. 3, the dotted line shows a Mollier diagram when the circulation composition ratio is an initial value, and the solid line shows a Mollier diagram when the circulation composition ratio changes from the initial value. The process from states C1 to C2 indicates the adiabatic compression process by the compressor 1. The process from the state C2 to C3 represents the condensation process by the condenser 2. The process from the state C3 to C4 represents a pressure reduction process by the pressure reduction unit 4. The process from the state C4 to C1 represents the evaporation process by the evaporator 5. The state C5 on the saturated liquid line and the state C6 on the saturated vapor line each have a pressure of Ps.

(3) As shown in FIG. 3, the Mollier diagram changes as the circulating composition ratio of the non-azeotropic refrigerant mixture changes. In particular, the temperature (evaporation temperature) during the evaporation process at the same pressure increases. As a result, the temperature difference between the non-azeotropic mixed refrigerant and the heat medium to be cooled decreases, and the cooling capacity of the refrigeration cycle apparatus 100 decreases.

Therefore, in the refrigeration cycle apparatus 100, the temperature in the state C4 when the circulation composition ratio is the initial value (the temperature in the state C4 in the dotted Mollier diagram in FIG. 3) is set as the reference temperature Tr, and the temperature is actually measured by the temperature sensor 101. By changing the drive frequency fc of the compressor 1 according to the difference between the measured temperature T1 and the reference temperature Tr, the change in the composition ratio of the non-azeotropic mixed refrigerant is reflected in the control of the refrigeration cycle apparatus 100. As a result, performance degradation of the refrigeration cycle apparatus 100 can be suppressed regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant. Further, in the refrigeration cycle apparatus 100, since the temperature sensor 101 that can be installed on the outer surface of the pipe is used, the composition ratio of the non-azeotropic refrigerant mixture is detected using a capacitance sensor that needs to be installed inside the pipe. It is easier to replace the failed temperature sensor 101 than in the case.

FIG. 4 is a flowchart showing the flow of the process of correcting the drive frequency fc performed by the control device 10 of FIG. The process shown in FIG. 4 is periodically called from a main routine (not shown) that performs integrated control of the refrigeration cycle apparatus 100. The same applies to the processing shown in FIGS. 7, 9, and 18. Hereinafter, a step is simply described as S.

As shown in FIG. 4, the control device 10 calculates the enthalpy Hsl from the discharge pressure Pd of the compressor 1 in S101, and advances the processing to S102. The correspondence m1 (Hsl = m1 (Pd)) between the discharge pressure Pd and the enthalpy Hsl is stored in the storage unit 11 in advance.

Control device 10 calculates reference temperature Tr from suction pressure Ps and enthalpy Hsl in S102, and advances the process to S103. The correspondence m2 (Tr = m2 (Ps, Hsl)) between the suction pressure Ps, the enthalpy Hsl, and the reference temperature Tr is stored in the storage unit 11 in advance. Control device 10 calculates a difference ΔT between temperature T1 and reference temperature Tr (ΔT = T1−Tr) in S103, and advances the processing to S104.

The control device 10 determines whether or not the difference ΔT is larger than the threshold value α (first threshold value) in S104. When difference ΔT is larger than threshold value α (YES in S104), control device 10 raises drive frequency fc by a fixed amount in S105, and returns the process to the main routine. As the drive frequency fc rises, the amount of non-azeotropic refrigerant mixture passing through the evaporator 5 per unit time increases. As a result, the amount of heat exchange in the evaporator 5 increases, and the evaporating temperature decreases. If difference ΔT is equal to or smaller than threshold α (NO in S104), control device 10 causes the process to proceed to S106.

Control device 10 determines whether or not difference ΔT is smaller than threshold value β (second threshold value) in S106. The threshold value β is smaller than the threshold value α. When difference ΔT is smaller than threshold value β (YES in S106), control device 10 lowers drive frequency fc by a fixed amount in S107, and returns the process to the main routine. As the drive frequency fc decreases, the amount of the non-azeotropic refrigerant mixture passing through the evaporator 5 per unit time decreases. As a result, the amount of heat exchange in the evaporator 5 decreases, and the evaporation temperature increases. When difference ΔT is equal to or greater than threshold value β (NO in S106), control device 10 returns the process to the main routine.

When the difference ΔT is equal to or greater than the threshold β and equal to or less than the threshold α, the drive frequency fc is not corrected and is stabilized. The thresholds α and β can be appropriately determined by simulation or actual machine experiment. The threshold values α and β are stored in the storage unit 11 in advance.

In the process shown in FIG. 4, since the correspondences m1 and m2 relating to the non-azeotropic mixed refrigerant are information obtained in advance, the difference ΔT is calculated regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant. It is possible. According to the processing shown in FIG. 4, the change in the circulation composition ratio can be reflected on the control of the refrigeration cycle apparatus 100 using the difference ΔT. As a result, performance degradation of the refrigeration cycle apparatus 100 can be suppressed regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant.

FIG. 5 is a diagram showing the temperature of the non-azeotropic mixed refrigerant according to the position between the inflow port and the outflow port of the evaporator 5 and the temperature of the air that exchanges heat with the non-azeotropic mixed refrigerant at the position. is there. In FIG. 5, a curve A1 represents a change in air temperature. A curve R0 represents a temperature change when the circulation composition ratio is an initial value. A curve R1 represents a temperature change when the drive frequency fc is not corrected (the processing shown in FIG. 4 is not performed) even if the circulation composition ratio changes. A curve R2 represents a temperature change when the drive frequency fc is corrected (the process shown in FIG. 4 is performed) according to a change in the composition ratio of the non-azeotropic mixed refrigerant.

As shown in FIG. 5, the temperature of the non-azeotropic mixed refrigerant in the evaporator 5 when the driving frequency fc is not corrected even when the circulation composition ratio changes (curve R1) is such that the circulation composition ratio is an initial value. In the case (curve R0), the temperature is higher than the temperature of the non-azeotropic refrigerant mixture in the evaporator 5. If the drive frequency fc is not corrected even if the circulation composition ratio changes, the evaporation temperature deviates from the target evaporation temperature and the temperature difference with the air becomes smaller than expected, so that the cooling capacity of the refrigeration cycle apparatus 100 is reduced to the desired level. Lower than ability.

On the other hand, when the drive frequency is corrected according to the change in the composition ratio of the non-azeotropic mixed refrigerant (curve R2), the temperature of the non-azeotropic mixed refrigerant in the evaporator 5 is such that the non-azeotropic mixed refrigerant has an initial composition ratio The temperature is almost the same as the temperature of the non-azeotropic refrigerant mixture in the evaporator 5 when the value does not change (curve R0). Since the evaporation temperature can be made closer to the target evaporation temperature, a decrease in the cooling capacity of the refrigeration cycle apparatus 100 due to a change in the circulation composition ratio can be suppressed.

FIG. 4 illustrates a case where the change in the circulation composition ratio is reflected in the control of the refrigeration cycle apparatus 100 by correcting the drive frequency fc. Any correction process may be used as long as the drive frequency fc is eventually corrected according to the difference ΔT. For example, the control target value of a specific parameter is realized by correcting the control target value of a specific parameter according to the difference ΔT. The driving frequency fc may be corrected to a value calculated as the driving frequency necessary for the operation.

Modification 1 of Embodiment 1
FIG. 4 illustrates the case where the drive frequency fc is increased or decreased by a constant amount. The method of correcting the drive frequency fc may be any method as long as the evaporation temperature can be brought close to a desired temperature. For example, the correction amount of the drive frequency fc may be proportional to the difference ΔT.

FIG. 6 shows the relationship between the amount of gas refrigerant in the receiver 3 and the temperature T1 detected by the temperature sensor 101 (curve E1), and the average temperature of saturated liquid and saturated vapor at the amount of gas refrigerant in the receiver 3 and the suction pressure Ps. FIG. 10 is a diagram also showing the relationship (curve E2). The average temperature of the saturated liquid and the saturated vapor at the suction pressure Ps is an average value of the temperature in the state C5 and the temperature in the state C6 in FIG. Since there is a correlation between the average value and the evaporation temperature, the refrigeration cycle apparatus 100 controls the evaporation temperature by controlling the average value.

As shown in FIG. 6, as the amount of gas refrigerant in the receiver 3 increases, the temperature T1 and the average temperature increase in a similar manner. The relationship between the amount of change in the temperature T1 and the amount of change in the average temperature can be approximated as a proportional relationship. Thus, in the first modification of the first embodiment, the correction amount of the drive frequency fc from the initial value f0 is made proportional to the difference ΔT.

FIG. 7 is a flowchart illustrating a flow of a process of correcting the drive frequency fc performed by the control device of the refrigeration cycle device according to the first modification of the first embodiment. The processes of S101 to S103 shown in FIG. 7 are the same as S101 to S103 shown in FIG.

制御 As shown in FIG. 7, after performing the steps S101 to S103 to calculate the difference ΔT, the control device advances the process to S114. In S114, the control device calculates a correction amount obtained by multiplying the difference ΔT by the proportional constant κ, updates the drive frequency fc by adding the correction amount to the initial value f0, and returns the process to a main routine (not shown). The proportional constant κ can be appropriately determined by simulation or actual machine experiment. The processing shown in FIG. 7 can also suppress a decrease in the performance of the refrigeration cycle apparatus due to a change in the composition ratio of the non-azeotropic mixed refrigerant.

Modification 2 of Embodiment 1
In the first embodiment, the case where temperature sensor 101 detects the temperature of the non-azeotropic mixed refrigerant flowing out of capillary tube 42 has been described. The temperature T1 detected by the temperature sensor 101 may be the temperature of the non-azeotropic mixed refrigerant flowing out of the pressure reducing unit 4. The temperature T1 may be the temperature of the non-azeotropic mixed refrigerant flowing out of the expansion valve 41, for example, as in a refrigeration cycle apparatus 100A according to a second modification of the first embodiment shown in FIG. By detecting the temperature of the non-azeotropic mixed refrigerant flowing out of the expansion valve 41, even in a configuration in which there is no pressure reducing device such as a capillary tube between the receiver 3 and the compressor 1 as in the refrigeration cycle device 100A, circulation is possible. The change in the composition ratio can be reflected in the control of the refrigeration cycle device. As a result, performance degradation of the refrigeration cycle device can be suppressed.

Modification 3 of Embodiment 1
If the temperature sensor 101 fails, the temperature T1 deviates from the actual temperature of the non-azeotropic refrigerant mixture. If the process shown in FIG. 4 is performed in a state where the temperature sensor 101 has failed, the operation of the refrigeration cycle apparatus 100 may become unstable. Therefore, when the temperature T1 is higher than the threshold value γ (third threshold value) (NO in S111) as in the process shown in FIG. 9, it is determined that the temperature sensor 101 has failed and the drive frequency fc is changed. You may make it raise by a fixed ratio (for example, 10%) (S112). By performing such a process, even when the temperature sensor 101 is out of order, a decrease in the amount of heat exchange in the condenser 2 and the evaporator 5 can be prevented, so that the capacity of the refrigeration cycle apparatus 100 is insufficient. Can be prevented.

As described above, according to the refrigeration cycle apparatus according to Embodiment 1 and Modifications 1 to 3, performance degradation of the refrigeration cycle apparatus can be suppressed regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant.

Embodiment 2 FIG.
When the refrigeration cycle apparatus is normal, the circulating composition ratio often stabilizes at a certain value while the non-azeotropic mixed refrigerant repeatedly circulates. Therefore, when the change in the circulating composition ratio is reflected in the control of the refrigeration cycle device by the correction processing described in the first embodiment, the drive frequency at which the operation of the compressor is stabilized and the control target value of the specific parameter are In the second and subsequent operations of the refrigeration cycle apparatus, the operation is often almost the same as in the first operation. Therefore, in the second embodiment, when the refrigeration cycle apparatus is stopped, the correction amount of the control target value of the specific parameter is stored in the storage unit of the control device. If the operation of the compressor is the second or subsequent operation, the drive frequency of the compressor is controlled so that the specific parameter becomes a value obtained by adding the correction amount stored in the storage unit to the initial value of the control target value. . As a result, the time required for correcting the control target value is shortened, so that the time required until the operation of the refrigeration cycle apparatus is stabilized can be shortened.

FIG. 10 is a flowchart showing a flow of processing performed at the time of starting operation of the refrigeration cycle apparatus according to Embodiment 2. The process shown in FIG. 10 is called by a main routine (not shown). As shown in FIG. 10, in S201, the control device determines whether the current operation of the refrigeration cycle device is the first operation. If the current operation of the refrigeration cycle device is the first operation (YES in S201), the control device sets the initial value to the control target value in S202 and returns the process to the main routine. When the operation of the refrigeration cycle apparatus is the second or subsequent operation (NO in S201), the control device sets a value obtained by adding the correction amount stored in the storage unit to the initial value to the control target value in S203. To return to the main routine.

As described above, according to the refrigeration cycle device according to Embodiment 2, performance degradation of the refrigeration cycle device can be suppressed regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant. Further, according to the refrigeration cycle apparatus according to Embodiment 2, it is possible to reduce the time required for the drive frequency of the compressor to stabilize.

Embodiment 3 FIG.
The circulation composition ratio also changes due to refrigerant leakage. Therefore, in a third embodiment, a description will be given of a configuration in which occurrence of refrigerant leakage is displayed on a display device.

FIG. 11 is a functional block diagram showing a configuration of a refrigeration cycle apparatus 300 according to Embodiment 3. The configuration of the refrigeration cycle apparatus 300 is such that a display device 301 is added to the configuration of the refrigeration cycle apparatus 100 shown in FIG. 1, and the control device 10 is replaced with a control device 30. The configuration other than these is the same, and thus the description will not be repeated.

(4) When a refrigerant leak such as a slow leak occurs, the circulation composition ratio of the refrigeration cycle apparatus 300 continues to change while the refrigerant leak occurs. Therefore, if the drive frequency fc is corrected while the refrigerant is leaking, the drive frequency fc may not be stable forever and may continue to rise.

駆動 In order to prevent the compressor 1 from malfunctioning, the driving frequency fc of the compressor 1 is usually set to an upper limit. If the drive frequency fc of the compressor 1 needs to be corrected to the upper limit or more to compensate for the shortage of the heat exchange amount due to the refrigerant leakage, the desired capacity cannot be realized, and the refrigeration is performed in a state of insufficient capacity. The cycle device will continue to operate.

Therefore, in the refrigeration cycle apparatus 300, when the drive frequency fc of the compressor 1 exceeds the reference frequency, it is determined that the non-azeotropic mixed refrigerant circulating in the refrigeration cycle apparatus 300 is insufficient, and the display device 301 Indicates that the non-azeotropic refrigerant mixture is insufficient. Since the user can know the shortage of the non-azeotropic mixed refrigerant through the display device 301, take measures such as adding or replacing the non-azeotropic mixed refrigerant before the refrigeration cycle apparatus 300 becomes insufficient in capacity. Can be.

FIG. 12 is a flowchart showing a flow of a refrigerant shortage notification process performed by the control device 30 of FIG. The process shown in FIG. 12 is called periodically by a main routine (not shown). As shown in FIG. 12, the control device 30 determines whether the driving frequency fc is higher than the reference frequency ν in S301. When drive frequency fc is higher than reference frequency ν (YES in S301), control device 30 displays a shortage of refrigerant on display device 301 in S302, and returns the process to the main routine. When drive frequency fc is equal to or lower than reference frequency ν (NO in S301), control device 30 returns the process to the main routine. Note that the reference frequency ν is a value smaller than the upper limit of the drive frequency of the compressor 1, and is determined as appropriate by simulation or actual machine experiment. The same applies to FIG. 14 described in the fourth embodiment.

As described above, according to the refrigeration cycle apparatus according to Embodiment 3, performance degradation of the refrigeration cycle apparatus can be suppressed regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant. Further, according to the refrigeration cycle apparatus according to Embodiment 3, the user can know the lack of refrigerant before the refrigeration cycle apparatus becomes insufficient in capacity.

Embodiment 4 FIG.
In the third embodiment, the case has been described in which the display device provided in the refrigeration cycle apparatus indicates that the non-azeotropic refrigerant mixture is insufficient. In the fourth embodiment, a case will be described in which the refrigeration cycle device includes a communication device, and the shortage of the non-azeotropic mixed refrigerant is transmitted to an external display device by the communication device. According to the refrigeration cycle apparatus according to Embodiment 4, the user need not always be near the refrigeration cycle apparatus and monitor the occurrence of refrigerant shortage. The user can be informed of the shortage of the refrigerant before the refrigeration cycle apparatus becomes insufficient in capacity by receiving a notification from a maintenance manager located at a remote place.

FIG. 13 is a diagram showing a configuration of a refrigeration cycle apparatus 400 according to Embodiment 4. The configuration of the refrigeration cycle apparatus 400 is such that a communication device 401 is added to the configuration of the refrigeration cycle apparatus 100 shown in FIG. 1, and the control device 10 is replaced with a control device 40. The configuration other than these is the same, and thus the description will not be repeated. The communication device 401 is connected to an external display device 901 via the Internet, for example.

FIG. 14 is a flowchart showing the flow of a refrigerant shortage notification process performed by the control device 40 of FIG. The process shown in FIG. 14 is periodically called by a main routine (not shown). As shown in FIG. 14, the control device 40 determines whether the driving frequency fc is higher than the reference frequency ν in S401. When the drive frequency fc is higher than the reference frequency ν (YES in S401), in S402, the control device 40 transmits a refrigerant shortage to the external display device 901 via the communication device 401, and returns the process to the main routine. When drive frequency fc is equal to or lower than reference frequency ν (NO in S401), control device 40 returns the process to the main routine.

As described above, according to the refrigeration cycle apparatus according to Embodiment 4, it is possible to suppress a decrease in the performance of the refrigeration cycle apparatus regardless of the number of refrigerants contained in the non-azeotropic mixed refrigerant. Further, according to the refrigeration cycle apparatus according to Embodiment 4, it is possible to know in a remote place that the non-azeotropic mixed refrigerant circulating in the refrigeration cycle apparatus is insufficient.

Embodiment 5 FIG.
When the non-azeotropic mixed refrigerant leaks from the refrigeration cycle device, it is necessary to eliminate the shortage of the non-azeotropic mixed refrigerant in order for the refrigeration cycle device to exhibit desired performance. As a method of resolving the shortage of the non-azeotropic mixed refrigerant, a method of adding the non-azeotropic mixed refrigerant to make up the shortage (additional charge), and a method of removing the non-azeotropic mixed refrigerant remaining in the refrigeration cycle apparatus by the refrigeration cycle apparatus A method (recharging) of replacing by an amount determined in the specification can be cited.

すると If the leakage of the non-azeotropic mixed refrigerant continues, the amount of change in the circulation composition ratio increases. Depending on the amount of the change, even if the non-azeotropic mixed refrigerant is additionally charged, the drive frequency of the compressor may need to be higher than the upper limit in order to restore the desired performance to the refrigeration cycle device. In such a case, it is necessary to recharge. Therefore, in a fifth embodiment, a description will be given of a configuration for determining whether or not additional charging is possible. According to the refrigeration cycle apparatus of the fifth embodiment, since the user can know whether to perform additional charging or recharging, appropriate measures can be taken against a shortage of refrigerant.

In the refrigeration cycle device according to Embodiment 5, similarly to the refrigeration cycle device according to Embodiment 2, when the refrigeration cycle device is stopped, the correction amount of the control target value of the specific parameter is stored in the storage unit of the control device. . Further, in the refrigeration cycle apparatus according to Embodiment 5, similarly to the refrigeration cycle apparatus according to

Embodiment

3 or 4, the display device indicates that the refrigerant is insufficient.

FIG. 15 is a flowchart illustrating a flow of a process of determining whether or not additional charging is possible, which is performed by the control device of the refrigeration cycle apparatus according to Embodiment 5. The process shown in FIG. 15 is called by a main routine (not shown).

As shown in FIG. 15, the control device calculates the shortage of the non-azeotropic mixed refrigerant from the initial refrigerant amount and the correction amount of the control target value stored in the storage unit in S501, and proceeds to S502. . In S502, the control device calculates a predicted correction amount when the shortage of the non-azeotropic mixed refrigerant is added to the refrigeration cycle device, and proceeds to S503. The control device determines in S503 whether the predicted correction amount is smaller than the reference correction amount δ. The reference correction amount δ is a value calculated based on the upper limit of the drive frequency fc of the compressor, and is stored in the storage unit in advance.

If the predicted correction amount is smaller than the reference correction amount δ (YES in S503), in S504, the control device displays on the display device that additional charging is possible, and returns the processing to the main routine. If the predicted correction amount is equal to or larger than the reference correction amount δ (NO in S503), the control device displays in S505 that recharging is necessary on the display device, and returns the processing to the main routine.

As described above, according to the refrigeration cycle apparatus according to Embodiment 5, it is possible to suppress a decrease in performance of the refrigeration cycle apparatus regardless of the number of refrigerants included in the non-azeotropic mixed refrigerant. Further, according to the refrigeration cycle apparatus according to Embodiment 5, the user can take appropriate measures against the shortage of the refrigerant.

Embodiment 6 FIG.
In the first embodiment, the configuration has been described in which the refrigerant flowing out of the refrigerant container is returned to the compressor via the second pressure reducing device. In the sixth embodiment, in order to ensure the degree of supercooling, a configuration in which heat exchange is performed between the non-azeotropic mixed refrigerant flowing out of the refrigerant container and the non-azeotropic mixed refrigerant flowing out of the second decompression device. explain. According to the refrigeration cycle apparatus according to Embodiment 6, the efficiency of the refrigeration cycle apparatus can be improved.

FIG. 16 is a functional block diagram showing a configuration of a refrigeration cycle apparatus 600 according to Embodiment 6. The configuration of the refrigeration cycle apparatus 600 is such that an internal heat exchanger 7 (third heat exchanger), a temperature sensor 104, and a pressure sensor 105 are added to the configuration of the refrigeration cycle apparatus 100 shown in FIG. 1, a configuration in which the capillary tube 42 and the control device 10 are replaced with a compressor 1B, an expansion valve 42B (second pressure reducing device), and a control device 60, respectively. The configuration other than these is the same, and thus the description will not be repeated.

圧縮 As shown in FIG. 16, the compressor 1B has an injection port communicating with the compression mechanism. The internal heat exchanger 7 is connected between the receiver 3 and the expansion valve 41. The non-azeotropic refrigerant mixture flowing out of the expansion valve 42B passes through the internal heat exchanger 7, and is then sucked into an injection port of the compressor 1B. In the internal heat exchanger 7, the non-azeotropic mixed refrigerant flowing out of the receiver 3 is cooled by the non-azeotropic mixed refrigerant flowing out of the expansion valve 42B.

The temperature sensor 101 detects the temperature T1 of the non-azeotropic refrigerant mixture flowing between the expansion valve 42B and the internal heat exchanger 7. The temperature sensor 104 detects the temperature T2 of the non-azeotropic refrigerant mixture flowing between the internal heat exchanger 7 and the expansion valve 41. The pressure sensor 102 detects the pressure Ps of the non-azeotropic mixed refrigerant flowing between the evaporator 5 and the compressor 1B. The pressure sensor 103 detects the pressure Pd of the non-azeotropic refrigerant mixture discharged from the compressor 1B. The pressure sensor 105 detects the pressure Pinj (specific pressure) of the non-azeotropic mixed refrigerant flowing between the expansion valve 42B and the internal heat exchanger 7.

The control device 60 controls the amount of non-azeotropic refrigerant mixture discharged by the compressor 1B per unit time by controlling the drive frequency fc of the compressor 1B. Control device 60 receives temperatures T1 and T2 and pressures Ps, Pd and Pinj from

temperature sensors

101 and 104 and

pressure sensors

102, 103 and 105, respectively. The control device 60 includes a storage unit 61. The storage unit 61 stores, for example, physical property values of the non-azeotropic refrigerant mixture and control target values of specific parameters in advance.

FIG. 17 is a Mollier chart showing the relationship among the pressure, enthalpy, and temperature of the non-azeotropic refrigerant mixture. As shown in FIG. 17, a process from the state C61 to C64 via C62 and C63 represents an adiabatic compression process by the compressor 1B. The process from the state C61 to C62 represents an adiabatic compression process between the suction port and the injection port. The process from state C63 to C64 represents an adiabatic compression process between the injection port and the discharge port. When the non-azeotropic mixed refrigerant having a lower enthalpy than the enthalpy in the state C62 flows into the injection port from the internal heat exchanger 7, the state of the non-azeotropic mixed refrigerant changes from the state C62 to the state C63.

過程 The process from state C64 to C65 represents the condensation process by the condenser 2. The process from the state C65 to C66 represents a heat exchange process in the internal heat exchanger 7. A supercooling degree is ensured in the heat exchange process. The process from state C66 to C68 represents a pressure reduction process by the expansion valve 41. The process from the state C68 to C61 represents an evaporation process by the evaporator 5. The process from state C66 to C67 represents a pressure reduction process by the expansion valve 42B. The process from state C67 to C69 represents a heat exchange process in internal heat exchanger 7. The non-azeotropic mixed refrigerant in the state C69 flows into the injection port of the compressor 1B.

FIG. 18 is a flowchart showing the flow of the process of correcting the drive frequency fc performed by the control device 60 of FIG. The flowchart illustrated in FIG. 18 is a flowchart in which S <b> 101 in the flowchart illustrated in FIG. 4 is replaced with S <b> 601. Other processes are the same.

制御 As shown in FIG. 18, in S601, the control device 60 calculates the enthalpy Hsl from the discharge pressure Pd and the temperature T2 of the compressor 1B, and proceeds to S102. The correspondence m3 (Hsl = m3 (Pd, T2)) between the discharge pressure Pd, the temperature T2, and the enthalpy Hsl is stored in the storage unit 61 in advance. The control device 60 performs S102 to S107, corrects the drive frequency fc, and returns the processing to the main routine.

As described above, according to the refrigeration cycle apparatus according to Embodiment 6, it is possible to suppress a decrease in performance of the refrigeration cycle apparatus regardless of the number of refrigerants included in the non-azeotropic mixed refrigerant. Further, according to the refrigeration cycle apparatus according to Embodiment 6, the efficiency of the refrigeration cycle apparatus can be improved.

各 The embodiments disclosed this time are also planned to be appropriately combined and implemented within a range not inconsistent. The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1, 1B compressor, 2 condenser, 3 receiver, 4 decompressor, 5 evaporator, 7 internal heat exchanger, 10, 30, 40, 60 controller, 11, 61 storage, 41, 42B expansion valve, 42 Capillary tube, 100, 100A, 300, 400, 600 {Refrigeration cycle device, 101, 104} Temperature sensor, 102, 103, 105} Pressure sensor, 301,901} Display device, 401} Communication device.

Claims

A refrigeration cycle device in which a non-azeotropic mixed refrigerant having a specific composition ratio circulates,
A compressor,
A first heat exchanger;
A refrigerant container,
A decompression unit;
A second heat exchanger,
The non-azeotropic mixed refrigerant circulates in the order of the compressor, the first heat exchanger, the refrigerant container, the decompression unit, and the second heat exchanger,
The driving frequency of the compressor in the first case is higher than the driving frequency of the compressor in the second case,
In the first case, a difference between a first temperature and a reference temperature of the non-azeotropic refrigerant mixture at a specific pressure is larger than a first threshold value,
In the second case, the difference is smaller than the first threshold,
The refrigeration cycle apparatus, wherein the specific pressure is a pressure of the non-azeotropic mixed refrigerant flowing out of the pressure reducing unit.
At least a part of the non-azeotropic mixed refrigerant is vaporized in the refrigerant container,
The reference temperature, when the composition ratio of the non-azeotropic mixed refrigerant of the liquid flowing into the decompression unit is the specific composition ratio, the enthalpy of the non-azeotropic mixed refrigerant of the liquid flowing into the decompression unit and the The refrigeration cycle apparatus according to claim 1, wherein the temperature is a temperature of the non-azeotropic mixed refrigerant corresponding to a specific pressure.
The pressure reducing unit includes a first pressure reducing device and a second pressure reducing device,
The non-azeotropic mixed refrigerant circulates in the order of the compressor, the first heat exchanger, the refrigerant container, the first decompression device, and the second heat exchanger, and the compressor, the first heat exchanger The refrigeration cycle apparatus according to claim 1, wherein the refrigerant circulates in the order of an exchanger, the refrigerant container, and the second pressure reducing device.
A third heat exchanger,
The non-azeotropic mixed refrigerant circulates in the order of the compressor, the first heat exchanger, the refrigerant container, the third heat exchanger, the first pressure reducing device, and the second heat exchanger, The refrigeration cycle apparatus according to claim 3, wherein the refrigerant circulates in the order of a compressor, the first heat exchanger, the refrigerant container, the third heat exchanger, the second pressure reducing device, and the third heat exchanger.
The refrigeration cycle apparatus according to claim 3 or 4, wherein the first temperature is a temperature of the non-azeotropic mixed refrigerant flowing out of the second pressure reducing device.
The drive frequency of the compressor when the difference is smaller than a second threshold is smaller than the drive frequency of the compressor when the difference is larger than the second threshold,
The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the second threshold value is smaller than the first threshold value.
A control device for controlling the compressor,
Further comprising a display device,
The control device according to any one of claims 1 to 6, wherein when the drive frequency of the compressor exceeds a reference frequency, the control device displays on the display device that the non-azeotropic refrigerant mixture is insufficient. A refrigeration cycle apparatus as described in the above.
A control device for controlling the compressor,
Further comprising a communication device,
The control device communicates that the non-azeotropic refrigerant mixture is insufficient to an external display device via the communication device when the drive frequency of the compressor exceeds a reference frequency. 7. The refrigeration cycle apparatus according to any one of 6.
Further comprising a control device for controlling the compressor,
The control device includes:
Correct the control target value of the specific parameter according to the difference,
When the refrigeration cycle device is stopped, the correction amount of the control target value is stored,
The drive frequency of the compressor according to any one of claims 1 to 6, wherein the drive frequency of the compressor is controlled such that the specific parameter has a value obtained by adding the stored correction amount to an initial value of the control target value. A refrigeration cycle apparatus as described in the above.
The control device includes:
Calculating the shortage of the non-azeotropic mixed refrigerant from the initial refrigerant amount of the non-azeotropic mixed refrigerant and the stored correction amount,
When the shortage is added to the refrigeration cycle device, calculate a predicted correction amount of the control target value,
When the predicted correction amount is smaller than the reference correction amount, it is notified that it is possible to add the same amount of the non-azeotropic mixed refrigerant as the shortage amount,
When the predicted correction amount is larger than the reference correction amount, it is necessary to replace the non-azeotropic mixed refrigerant in the refrigeration cycle apparatus with an amount of the non-azeotropic mixed refrigerant specified in the specification of the refrigeration cycle apparatus. The refrigeration cycle apparatus according to claim 9, which informs the fact.
The drive frequency of the compressor when the first temperature is higher than the third threshold is higher than the drive frequency of the compressor when the first temperature is lower than the third threshold,
The refrigeration cycle apparatus according to any one of claims 1 to 10, wherein the third threshold value is larger than the first threshold value.
The non-azeotropic refrigerant mixture contains carbon dioxide,
The refrigeration cycle apparatus according to any one of claims 1 to 11, wherein a ratio of the carbon dioxide in the non-azeotropic mixed refrigerant is 50% by weight or less.
The refrigeration cycle apparatus according to claim 12, wherein the non-azeotropic mixed refrigerant includes R463A.