JP3731174B2 - Refrigeration cycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration cycle such as an air conditioner in which a non-azeotropic refrigerant mixture composed of two or more refrigerants having different boiling points is enclosed.
[0002]
[Prior art]
FIG. 8 is a block diagram showing a refrigeration cycle of a conventional air conditioner. In the figure, reference numeral 1 denotes a compressor that sucks and compresses a low-temperature and low-pressure gas refrigerant in an accumulator 6 to form a high-temperature and high-pressure gas refrigerant. A four-way valve, 3 is an outdoor heat exchanger that operates as a condenser, 4 is a throttle device, and 5 is an indoor heat exchanger that operates as an evaporator.
[0003]
In the refrigeration cycle of the conventional air conditioner configured as described above, for example, in a cooling operation, high-temperature and high-pressure gas refrigerant is discharged from the compressor 1 and enters the outdoor heat exchanger 3 through the four-way valve 2. . This gas refrigerant is heat-exchanged with the outside air by the outdoor heat exchanger, becomes a liquid refrigerant, and enters the expansion device 4. The liquefied refrigerant is depressurized by the expansion device 4 and is fed into the indoor heat exchanger 5 as a two-phase refrigerant having a low dryness. Then, heat is exchanged with indoor air in the indoor heat exchanger 5 to evaporate, and it becomes a two-phase refrigerant having high dryness, and is sucked into the compressor 1 again via the four-way valve 2 and the accumulator 6. At this time, excess refrigerant remaining in the refrigerant circuit is stored in the accumulator 6.
[0004]
[Problems to be solved by the invention]
In the conventional refrigeration cycle as described above, for example, when a non-azeotropic refrigerant mixture in which R (Freon) 134a is mixed in a ratio of 52% by weight, R125 is 25% by weight, and R32 is 23% by weight is used in the accumulator 6. Among the excess refrigerant stored, R32 and R125, which are low-boiling refrigerants, are likely to be gasified, so that the refrigerant circulating in the refrigeration cycle has a larger composition of R32 and R125, which are low-boiling refrigerants, and is stored in the accumulator 6. When the amount of surplus refrigerant to be changed changes, the composition of the refrigerant circulating in the refrigeration cycle also changes, which causes fluctuations in the physical properties of the circulating refrigerant, fluctuations in operating pressure, capacity, etc. .
[0005]
In addition, it is known that the heat transfer coefficient in the heat exchanger pipe is smaller than that of a conventional single refrigerant such as R22 due to the non-azeotropic property of the mixed refrigerant. There was also a problem that (efficiency) decreased.
[0006]
The present invention has been made to solve such a problem, and provides a refrigeration cycle that can suppress fluctuations in the composition of circulating refrigerant due to excess refrigerant and improve COP even when a non-azeotropic refrigerant mixture is used. For the purpose.
[0007]
[Means for Solving the Problems]
In the refrigeration cycle according to the present invention, a non-azeotropic refrigerant mixture composed of two or more kinds of refrigerants having different boiling points is made high-temperature and high-pressure by a compressor, and flows into the four-way valve again through the four- way valve, the condenser, the expansion device, and the evaporator. In the refrigeration cycle that circulates through the accumulator , a receiver, a first two-way valve, and a capillary that adjusts the refrigerant flow rate are provided, respectively , and a first pipe that connects the compressor and the four-way valve is connected to the receiver. A heat exchanger for exchanging heat between the low - pressure non-azeotropic mixed refrigerant from the accumulator sucked into the compressor and the high - temperature high - pressure non-azeotropic mixed refrigerant passing through the first bypass path; two-way valve is provided for, in which a non-azeotropic refrigerant in the high pressure in the receiver, which is heat-exchanged with the second bypass passage for introducing into the accumulator by the heat exchanger.
[0008]
The first temperature sensor installed on the discharge side of the compressor, the second temperature sensor installed in the condenser, the detected temperature of the first temperature sensor, and the detected temperature of the second temperature sensor The difference is calculated, and the value is compared with a preset first allowable value. When the value is equal to or lower than the lower limit value of the first allowable value, the first two-way valve is opened. when the value exceeds the upper limit of the first tolerance value is obtained by a first valve control means for the second two-way valve in the open state.
[0009]
Further, a third temperature sensor installed on the suction side of the compressor, a fourth temperature sensor installed in the evaporator, a detection temperature of the third temperature sensor, and a detection temperature of the fourth temperature sensor The difference is calculated, and the value is compared with a preset second allowable value. When the value is equal to or lower than the lower limit value of the second allowable value, the first two-way valve is opened. when the value exceeds the upper limit of the second tolerance value is obtained by a second valve control means for the second two-way valve in the open state.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1. FIG.
FIG. 1 is a block diagram showing, for example, a refrigeration cycle of an air conditioner according to Embodiment 1 of the present invention, and shows a state during cooling operation. In addition, the same code | symbol is attached | subjected to the part which is the same as that of the former demonstrated in FIG. 8, or an equivalent, and description is abbreviate | omitted.
[0012]
In the figure, 11 is a receiver, 12 is a first bypass passage branched from a pipe connecting the compressor 1 and the four-way valve 2 and connected to the receiver 11, and 13 is a first bypass for opening and closing the first bypass passage 12. A two-way valve 14 is a capillary that adjusts the amount of high-temperature and high-pressure gas refrigerant flowing through the first bypass passage 12, and 15 is a low-temperature and low-pressure gas refrigerant sucked into the compressor 1 and passes through the first bypass passage 12. A high / low pressure heat exchanger for exchanging heat with a high-temperature / high-pressure gas refrigerant, 16 is a second bypass passage branched from the inlet pipe of the accumulator 6 and connected to the bottom of the receiver 11, and 17 is a second bypass passage 16. It is the 2nd two-way valve which opens and closes. Note that the refrigerant used in the present embodiment is a non-azeotropic refrigerant mixture composed of two or more kinds of refrigerants having different boiling points.
[0013]
Operation during cooling operation in the refrigeration cycle configured as described above will be described. It is assumed that the first two-way valve is open at the start of operation.
High-temperature and high-pressure gas refrigerant is discharged from the compressor 1 and enters the outdoor heat exchanger 3 through the four-way valve 2. This gas refrigerant is heat-exchanged with the outside air by the outdoor heat exchanger 3 to become a liquid refrigerant and enters the expansion device 4. The liquefied refrigerant is depressurized by the expansion device 4 and is sent to the indoor heat exchanger 5 as a low-temperature and low-pressure two-phase refrigerant having a dryness of 0.2 to 0.3. Then, heat is exchanged with indoor air in the indoor heat exchanger 5 to evaporate, and it becomes a low-temperature and low-pressure two-phase refrigerant having a dryness of 0.9 to 1.0, and is compressed again via the four-way valve 2 and the accumulator 6. Inhaled by machine 1.
[0014]
On the other hand, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows toward the first bypass passage 12 by opening the first two-way valve 13, passes through the capillary 14, and further, the high-low pressure heat Heat exchange is performed with the low-temperature and low-pressure gas refrigerant sucked into the compressor 1 while passing through the exchanger 15, that is, the refrigerant is cooled to become a high-pressure liquid refrigerant and stored in the receiver 11 as surplus refrigerant.
[0015]
Here, the composition change of the surplus refrigerant will be described with reference to FIG. FIG. 2 is a comparison diagram of the composition change of the circulating refrigerant when the non-azeotropic refrigerant mixture is stored in the receiver and the accumulator. When excess non-azeotropic refrigerant mixture is stored in the accumulator 6 of the conventional refrigeration cycle shown in FIG. 8, the composition change becomes large because the refrigerant mixture is at a low pressure (see A). On the other hand, in the case of this embodiment, since the high-temperature surplus mixed refrigerant (liquid state) is stored in the receiver 11, the composition change of the mixed refrigerant circulating in the refrigeration cycle becomes small (see b).
[0016]
When the operating state changes due to changes in the outside air temperature, air conditioning load, etc. during steady operation and the refrigerant becomes insufficient, the second two-way valve 17 is opened and the surplus stored in the receiver 11 Refrigerant is supplied to the accumulator 6.
[0017]
As described above, according to the first embodiment, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1, that is, surplus refrigerant is cooled through the first bypass 12 and stored in the receiver 11. Therefore, it is possible to eliminate surplus refrigerant in the accumulator 6, to suppress a change in composition of the refrigerant circulating in the refrigeration cycle, and to prevent fluctuations in operating pressure and capacity.
[0018]
Moreover, since the refrigerant | coolant suck | inhaled by the compressor 1 can be reliably gasified by eliminating the excess refrigerant | coolant in the accumulator 6, the efficiency of the compressor 1 improves and COP of a refrigerating cycle improves. effective.
[0019]
Embodiment 2. FIG.
FIG. 3 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 2 of the present invention, and shows a state during cooling operation. In addition, the same code | symbol is attached | subjected to the same or equivalent part as Embodiment 1 demonstrated in FIG. 1, and description is abbreviate | omitted.
[0020]
In the second embodiment, the receiver 11 is formed extending downward with the bottom of the accumulator 6 as a partition plate 18, and the partition plate 18 converts the high-temperature and high-pressure gas refrigerant guided to the receiver 11 into a low-temperature and low-pressure gas in the accumulator 6. It is for exchanging heat with the gas refrigerant. The accumulator 6 and the receiver 11 are connected by a second bypass path 16, and the receiver 11 is connected to a pipe connecting the compressor 1 and the four-way valve 2 via the first bypass path 12. The first bypass passage 12 is provided with a first two-way valve 13 and a capillary tube 14, and the second bypass passage 16 is provided with a second two-way valve 17.
[0021]
Next, the operation during the cooling operation will be described. Since the circulation of the refrigerant in the second embodiment is the same as that in the first embodiment, description of the operation is omitted.
When a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 by the opening of the first two-way valve 13 is guided to the first bypass 12, it enters the receiver 11 through the capillary 14. At this time, the high-temperature and high-pressure gas refrigerant that has entered the receiver 11 is heat-exchanged with the low-temperature and low-pressure gas refrigerant in the accumulator 6 by the partition plate 18 to become high-pressure liquid refrigerant, and is stored as surplus refrigerant.
[0022]
In this embodiment as well, when the refrigerant is short in the refrigeration cycle, the second two-way valve 17 is opened, and the surplus refrigerant stored in the receiver 11 is replenished to the accumulator 6.
[0023]
In this way, the receiver 11 is formed by extending the bottom of the accumulator 6 with the partition plate 18 extending downward, so that the high-temperature and high-pressure gas refrigerant passing through the first bypass 12 can be cooled without the high-low pressure heat exchanger 15. There is an effect that can be done.
[0024]
Embodiment 3. FIG.
FIG. 4 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 3 of the present invention, and shows a state during cooling operation. In addition, the same code | symbol is attached | subjected to the same or equivalent part as Embodiment 1 demonstrated in FIG. 1, and description is abbreviate | omitted.
[0025]
In the figure, 21 is attached to a pipe connecting the compressor 1 and the four-way valve 2, and a first temperature sensor for detecting the temperature Td of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1, and 22 operates as a condenser. This is a second temperature sensor that detects the temperature Tc of the refrigerant that is attached to the center of the outdoor heat exchanger 3 and that is cooled by the outdoor heat exchanger 3.
[0026]
31 is a control circuit for controlling the compressor 1 of the air conditioner, for example, and includes the first valve control means of the present invention. For example, when adjusting the amount of excess refrigerant during cooling operation, the first temperature sensor 21 is subtracted from the detected temperature Td of the second temperature sensor 22 to obtain the discharge superheat degree SHd, and the lower limit value of the superheat degree SHd and the first allowable value of the preset discharge superheat degree When the discharge superheat degree SHd is less than or equal to the lower limit value of the first allowable value, the first two-way valve 13 is opened through the valve drive circuit 32, and the discharge superheat degree SHd is equal to the first allowable value. When the lower limit is exceeded, the first two-way valve 13 is closed.
[0027]
Further, during steady operation, the discharge superheat degree SHd is compared with the upper limit value of the first allowable value, and when the discharge superheat degree SHd exceeds the upper limit value of the first allowable value, the first value is passed through the valve drive circuit 32. The two two-way valve 17 is opened, and the second two-way valve 17 is closed when the discharge superheat degree SHd is not more than the upper limit value of the first allowable value. In addition, the 1st and 2nd two-way valves 13 and 17 mentioned above consist of an electromagnetic valve, for example.
[0028]
Next, the operation of the refrigeration cycle configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the refrigeration cycle of the air conditioner according to the third embodiment, for example. In addition, since operation | movement of each part when circulating the above-mentioned non-azeotropic refrigerant mixture is the same as Embodiment 1, description is abbreviate | omitted.
[0029]
When the compressor 1 is started, the control circuit 31 opens the first two-way valve 13 through the valve drive circuit 32 and starts an operation for storing excess refrigerant in the receiver 11. First, the temperature Tc of the two-phase refrigerant in the outdoor heat exchanger 3 is input through the second temperature sensor 22, and then the temperature Td of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is input to the first temperature sensor 21. Enter through. Then, the detected temperature Tc of the second temperature sensor 22 is subtracted from the detected temperature Td to obtain the discharge superheat degree SHd, and the lower limit of the superheat degree SHd and the first allowable value of the preset discharge superheat degree Compare the value.
[0030]
Since the lower limit value of the first allowable value is higher than the discharge superheat degree SHd at the start of operation, the open state of the first two-way valve 13 is maintained, and again the detected temperature Tc of the second temperature sensor 22 The detection temperature Td of the first temperature sensor 21 is entered. As the operation is repeated, the refrigerant in the accumulator 6 runs out, the suction temperature of the compressor 1 rises, and the discharge superheat degree SHd based on the detected temperature Tc and the detected temperature Td is the lower limit value of the first allowable value. Is exceeded, the first two-way valve 13 is closed through the valve drive circuit 32, and the storage of excess refrigerant in the receiver 11 is terminated.
[0031]
During the steady operation, the discharge superheat degree SHd is compared with the upper limit value of the first allowable value, and when the discharge superheat degree SHd is less than or equal to the upper limit value of the first allowable value, the second two-way valve 17 is closed. Maintain state. In addition, when the operating state changes due to changes in the outside air temperature, the air conditioning load, etc., and the circulating refrigerant becomes insufficient, the discharge superheat degree SHd increases, but due to the lack of refrigerant, the discharge superheat degree SHd is the first. When the upper limit value of the allowable value is exceeded, the second two-way valve 17 is opened, and the surplus refrigerant stored in the receiver 11 is supplied to the accumulator 6. Then, the second two-way valve 17 is closed when the discharge superheat degree SHd becomes less than or equal to the upper limit value of the first allowable value due to this replenishment.
[0032]
As described above, according to the third embodiment, when the compressor 1 is started, the first two-way valve 13 is opened, and the detected temperature Td of the first temperature sensor 21 is changed to that of the second temperature sensor 22. The detected superheat degree SHd is obtained by subtracting the detected temperature Tc, and the superheat degree SHd is compared with a lower limit value of a first allowable value of the preset discharge superheat degree. When the value is equal to or lower than the lower limit value of the allowable value, the first two-way valve 13 is kept open and the excess refrigerant is continuously stored in the receiver 11, and the discharge superheat degree SHd exceeds the lower limit value of the first allowable value. In this case, since the first two-way valve 13 is closed and its storage is stopped, the surplus refrigerant is reliably stored in the accumulator 6 even if the operating conditions such as the outside air temperature and the pipe extension are changed. Can be stored in the receiver 11, so that the freezing cycle There is an effect that it is possible to suppress the change in composition of the refrigerant circulating in the.
[0033]
Further, during steady operation, when the discharge superheat degree SHd exceeds the upper limit value of the first allowable value, the second two-way valve 17 is opened to supply the surplus refrigerant in the receiver 11 to the accumulator 6, When the discharge superheat degree SHd becomes equal to or lower than the upper limit value of the first allowable value, the second two-way valve 17 is closed and the replenishment is stopped. There is also an effect that it can be eliminated.
[0034]
In the third embodiment, the first and second temperature sensors 21 and 22 are attached to predetermined positions in the refrigeration cycle of the first embodiment, and the control of the surplus refrigerant has been described. , 22 may be provided in the refrigeration cycle shown in the second embodiment to control excess refrigerant.
[0035]
Embodiment 4 FIG.
FIG. 6 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 4 of the present invention, and shows a state during cooling operation. In addition, the same code | symbol is attached | subjected to the part which is the same as that of Embodiment 3 demonstrated in FIG. 4, or an equivalent, and description is abbreviate | omitted.
[0036]
In the refrigeration cycle of the present embodiment, a third temperature sensor 23 that is attached to the suction side of the compressor 1 and detects the temperature Ts of the low-temperature and low-pressure gas refrigerant sucked by the compressor 1 operates as an evaporator. A fourth temperature sensor 24 that is mounted at the center of the indoor heat exchanger 5 and detects the temperature Te of the refrigerant vaporized by the indoor heat exchanger 5 is provided.
[0037]
The control circuit 31 includes the second valve control means of the present invention. For example, when adjusting the amount of excess refrigerant during the cooling operation, the control circuit 31 uses the detected temperature Ts of the third temperature sensor 21 to the fourth temperature sensor. The detected superheat degree SHs is obtained by subtracting the detected temperature Te of 22 and the superheat degree SHs is compared with a lower limit value of a second allowable value of the preliminarily set intake superheat degree. The first two-way valve 13 is opened through the valve drive circuit 32 when the lower limit value of the second allowable value is less than the lower limit value of the second allowable value, and when the suction superheat degree SHs exceeds the lower limit value of the second allowable value. The direction valve 13 is closed.
[0038]
During steady operation, when the suction superheat degree SHs exceeds the upper limit value of the second allowable value, the second two-way valve 17 is opened through the valve drive circuit 32, and the suction superheat degree SHs is the second allowable value. When the value is equal to or lower than the upper limit value, the second two-way valve 17 is closed. Note that the second tolerance value of the present embodiment is set lower than the first tolerance value described in the third embodiment.
[0039]
Next, the operation of the refrigeration cycle configured as described above will be described with reference to FIG. FIG. 7 is a flowchart showing the operation of the refrigeration cycle of the air conditioner according to the fourth embodiment, for example. In addition, since operation | movement of each part when circulating the above-mentioned non-azeotropic refrigerant mixture is the same as Embodiment 1, description is abbreviate | omitted.
[0040]
When the compressor 1 is started, the control circuit 31 opens the first two-way valve 13 through the valve drive circuit 32 as described above, and starts an operation for storing excess refrigerant in the receiver 11. First, the temperature Te of the two-phase refrigerant in the indoor heat exchanger 5 is inputted through the fourth temperature sensor 24, and then the temperature Ts of the low-temperature and low-pressure gas refrigerant sucked into the compressor 1 is inputted to the third temperature sensor 23. Enter through. Then, the detected temperature Te of the fourth temperature sensor 24 is subtracted from the detected temperature Ts to obtain the suction superheat degree SHs, and the lower limit of the second allowable value of the superheat degree SHs and the preset suction superheat degree Compare the value.
[0041]
Since the lower limit value of the second allowable value is higher than the suction superheat degree SHs at the start of operation, the open state of the first two-way valve 13 is maintained, and the detected temperature Ts of the third temperature sensor 23 again. The detection temperature Te of the fourth temperature sensor 24 is entered. As the operation is repeated, the refrigerant in the accumulator 6 runs out, the intake temperature of the compressor 1 rises, and the intake superheat degree SHs based on the detected temperature Te and the detected temperature Ts is the lower limit value of the second allowable value. Is exceeded, the first two-way valve 13 is closed through the valve drive circuit 32, and the storage of excess refrigerant in the receiver 11 is terminated.
[0042]
During steady operation, the suction superheat degree SHs is compared with the upper limit value of the second allowable value, and when the suction superheat degree SHs is less than or equal to the upper limit value of the second allowable value, the second two-way valve 17 is closed. Maintain state. In addition, when the operating state changes due to changes in the outside air temperature, the air conditioning load, etc., and the circulating refrigerant becomes insufficient, the suction superheat degree SHs increases. However, due to the lack of refrigerant, the suction superheat degree SHs becomes the second superheat degree SHs. When the upper limit value of the allowable value is exceeded, the second two-way valve 17 is opened, and the surplus refrigerant stored in the receiver 11 is supplied to the accumulator 6. Then, when the replenishment causes the suction superheat degree SHs to become equal to or lower than the upper limit value of the second allowable value, the second two-way valve 17 is closed.
[0043]
As described above, according to the fourth embodiment, when the compressor 1 is started, the first two-way valve 13 is opened, and the detected temperature Ts of the third temperature sensor 23 is changed to that of the fourth temperature sensor 24. The detected superheat degree SHs is obtained by subtracting the detected temperature Te, and the superheat degree SHs is compared with a lower limit value of a second allowable value of the preset intake superheat degree. When the lower limit value of the allowable value is not exceeded, the first two-way valve 13 is opened and the excess refrigerant is continuously stored in the receiver 11, and the suction superheat degree SHs exceeds the lower limit value of the second allowable value. Since the first two-way valve 13 is closed and its storage is stopped, the receiver 11 can be reliably received without accumulating excess refrigerant in the accumulator 6 even if the operating conditions such as the outside air temperature and the pipe extension change. Can be stored in the refrigeration cycle There is an effect that it is possible to suppress the change in composition of the refrigerant ring.
[0044]
Further, during steady operation, when the suction superheat degree SHs exceeds the upper limit value of the second allowable value, the second two-way valve 17 is opened to supply surplus refrigerant in the receiver 11 to the accumulator 6, Since the second two-way valve 17 is closed and the replenishment is stopped when the suction superheat degree SHs becomes equal to or lower than the upper limit value of the second allowable value, even if the refrigerant becomes insufficient during operation. There is also an effect that it can be eliminated.
[0045]
In the fourth embodiment, as described above, the third and fourth temperature sensors 23 and 24 are attached to predetermined positions in the refrigeration cycle of the first embodiment, and the control of the surplus refrigerant has been described. These temperature sensors 23 and 24 may be provided in the refrigeration cycle shown in the second embodiment to control excess refrigerant.
[0046]
【The invention's effect】
As described above, according to the present invention, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is cooled via the first bypass and stored in the receiver. The refrigerant can be eliminated, the composition change of the refrigerant circulating in the refrigeration cycle can be suppressed to a small level, and fluctuations in operating pressure and capacity can be prevented. In addition, since the refrigerant sucked into the compressor can be reliably gasified by eliminating the excess refrigerant in the accumulator, the compressor efficiency is improved and the COP of the refrigeration cycle is improved. .
[0047]
Also, a first temperature sensor is provided on the discharge side of the compressor, and a second temperature sensor is provided on the condenser, and the difference between the detected temperature of the first temperature sensor and the detected temperature of the second temperature sensor is calculated. In addition, the value is compared with a preset first allowable value, and when the value is less than or equal to the lower limit value of the first allowable value, the first two-way valve is opened. Therefore, even if operating conditions such as outside air temperature and pipe extension change, excess refrigerant can be reliably stored in the receiver without accumulating in the accumulator, and therefore, the composition change of the refrigerant circulating in the refrigeration cycle can be kept small. There is an effect that can be. In addition, when the value exceeds the upper limit of the first allowable value, the second two-way valve is opened so that excess refrigerant in the receiver is supplied to the accumulator. Even if it becomes, there is an effect that it can be solved.
[0048]
Also, a third temperature sensor is provided on the suction side of the compressor and a fourth temperature sensor is provided on the evaporator, and the difference between the detected temperature of the third temperature sensor and the detected temperature of the fourth temperature sensor is calculated. In addition, the value is compared with a preset second allowable value, and when the value is less than or equal to the lower limit value of the first allowable value, the first two-way valve is opened. Therefore, even if operating conditions such as outside air temperature and pipe extension change, excess refrigerant can be reliably stored in the receiver without accumulating in the accumulator, and therefore, the composition change of the refrigerant circulating in the refrigeration cycle can be kept small. There is an effect that can be. In addition, when the value exceeds the upper limit of the second allowable value, the second two-way valve is opened so that excess refrigerant in the receiver is supplied to the accumulator. Even if it becomes, there is an effect that it can be solved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 1 of the present invention.
FIG. 2 is a comparison diagram of composition change of circulating refrigerant when non-azeotropic refrigerant mixture is stored in a receiver and an accumulator.
FIG. 3 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 2 of the present invention.
FIG. 4 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 3 of the present invention.
FIG. 5 is a flowchart showing an operation of a refrigeration cycle of an air conditioner according to Embodiment 3, for example.
FIG. 6 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 4 of the present invention.
FIG. 7 is a flowchart showing an operation of a refrigeration cycle of an air conditioner according to Embodiment 4, for example.
FIG. 8 is a block diagram showing a refrigeration cycle of a conventional air conditioner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four-way valve, 3 Outdoor heat exchanger, 4 Throttle device, 5 Indoor heat exchanger, 6 Accumulator, 11 Receiver, 12 1st bypass, 13 1st two-way valve, 14 Capillary, 15 High Low pressure heat exchanger,
16 Second bypass path, 17 Second two-way valve, 21 First temperature sensor, 22 Second temperature sensor, 23 Third temperature sensor, 24 Fourth temperature sensor, 31 Control circuit, 32 Valve drive circuit.

Claims (3)

A non-azeotropic refrigerant mixture consisting of two or more kinds of refrigerants having different boiling points is made high-temperature and high-pressure by a compressor, and again flows into a four-way valve via a four- way valve, a condenser, a throttling device, and an evaporator, and is circulated through an accumulator. In the refrigeration cycle,
A receiver,
A first two-way valve and a capillary for adjusting the refrigerant flow rate, respectively , and a first bypass passage connecting the receiver and a pipe connecting the compressor and the four-way valve;
A heat exchanger for exchanging heat between the low - pressure non-azeotropic refrigerant mixture from the accumulator sucked into the compressor and the high - temperature high - pressure non-azeotropic refrigerant mixture passing through the first bypass path;
A second two-way valve is provided, and includes a second bypass passage for introducing a high-pressure non-azeotropic refrigerant mixture in the receiver that has been heat-exchanged by the heat exchanger into the accumulator. Refrigeration cycle to be. A first temperature sensor installed on the discharge side of the compressor;
A second temperature sensor installed in the condenser;
The difference between the detected temperature of the first temperature sensor and the detected temperature of the second temperature sensor is calculated, and the value is compared with a preset first allowable value. When the value is less than or equal to the lower limit value of the allowable value, the first two-way valve is opened, and when the value exceeds the upper limit value of the first allowable value, the second two-way valve is opened. claim 1 Symbol placement of the refrigeration cycle comprising the <br/> the first valve control means. A third temperature sensor installed on the suction side of the compressor;
A fourth temperature sensor installed in the evaporator;
The difference between the detected temperature of the third temperature sensor and the detected temperature of the fourth temperature sensor is calculated, and the value is compared with a preset second allowable value. The first two-way valve is opened when it is below the lower limit value of the allowable value, and the second two-way valve is opened when the value exceeds the upper limit value of the second allowable value. claim 1 Symbol placement of the refrigeration cycle comprising the <br/> and second valve control means.

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