JPH11248267A - Refrigeration cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress fluctuation in the composition of circulating refrigerant due to excess refrigerant by coupling a four-way valve with a compressor, a condenser and an evaporator, coupling an accumulator and the evaporator, respectively, with the other end of the compressor and the condenser, and disposing throttle valves, respectively, between an inner receiver and the condenser and evaporator. SOLUTION: High temperature high pressure gas refrigerant delivered from a compressor 1 passes through a four-way valve 2 and enters into an outdoor heat exchanger 3 where heat is exchanged with outer air to produce liquid refrigerant flowing into a first throttle valve 4a. The refrigerant enters into a receiver 7 with pressure being reduced and cooled down to saturated liquid state by low temperature low pressure refrigerant flowing through an accumulator 6. When an equivalent evaporation temperature is sustained through temperature glide in two-phase region of the characteristics of nonazeotropic mixture refrigerant, pressure at the inlet of an indoor heat exchanger 5 increases before being brought to low temperature low pressure by a second throttle valve 4b. Since pressure of the mixture refrigerant stored in the receiver 7 is increased, excess refrigerant is not stored in the accumulator 6 and fluctuation in the composition of circulating refrigerant is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for an air conditioner or the like in which a non-azeotropic mixed refrigerant comprising two or more refrigerants having different boiling points is filled.

[0002]

2. Description of the Related Art FIG. 39 is a block diagram showing a refrigeration cycle of a conventional air conditioner. In FIG. 39, reference numeral 1 denotes a low-temperature low-pressure gas refrigerant in an accumulator 6 which is sucked and compressed, and a high-temperature high-pressure gas refrigerant is discharged. Compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger that operates as a condenser, 4 is a throttle device, 5
Is an indoor heat exchanger that operates as an evaporator.

In the refrigeration cycle of the conventional air conditioner configured as described above, for example, in a cooling operation, a high-temperature and high-pressure gas refrigerant is discharged from the compressor 1 and passes through the four-way valve 2 to the outdoor heat exchanger. Enter 3. 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. This refrigerant is decompressed by the expansion device 4 and is sent to the indoor heat exchanger 5 as a two-phase refrigerant having low dryness. Then, the refrigerant exchanges heat with the indoor air in the indoor heat exchanger 5 to evaporate, becomes a highly dry two-phase refrigerant, enters the accumulator 6 via the four-way valve 2, and returns to the compressor 1.
Inhaled. At this time, the excess refrigerant is stored in the accumulator 6.

FIG. 40 shows another conventional example. FIG. 40 is a block diagram of a conventional refrigeration cycle disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 46-14440.
The refrigeration cycle described in this publication is provided with a receiver 7 integrated with an accumulator 6 between the outdoor heat exchanger 3 and the indoor heat exchanger 5.
And the receiver 7 are separated by a partition plate 8. In the refrigeration cycle of this conventional air conditioner, the compressor 1
A gas refrigerant having a higher temperature and a higher pressure is discharged and enters the outdoor heat exchanger 3. The gas refrigerant exchanges heat with the outside air by the outdoor heat exchanger 3 to become a high-temperature two-phase refrigerant and enters the receiver 7. The high-temperature two-phase refrigerant in the receiver 7 exchanges heat with the low-temperature refrigerant in the accumulator 6 via the partition plate 8, and
And enters the squeezing device 4. This refrigerant is supplied to the expansion device 4
, And is sent to the indoor heat exchanger 5 as a low-dryness two-phase refrigerant. Then, in the indoor heat exchanger 5, heat is exchanged with the indoor air to evaporate, becoming a two-phase refrigerant having a high degree of dryness, entering the accumulator 6, and returning to the compressor 1 again.
Inhaled. At this time, surplus refrigerant is stored in the receiver 7 and the accumulator 6.

[0005]

In the above-described conventional refrigeration cycle, for example, R (Freon) 134a is
2% by weight, 25% by weight of R125, 23% by weight of R32
In the case of using a non-azeotropic mixed refrigerant mixed at a ratio of, the refrigerant circulating is a low-boiling-point refrigerant because many of the low-boiling-point refrigerants R32 and R125 are apt to be gasified among the excess refrigerant stored in the accumulator 6. When R32 and R125 have a relatively large composition, and thus the amount of the surplus refrigerant stored in the accumulator 6 changes, the composition of the circulating refrigerant also changes, which causes the physical properties of the circulating refrigerant to fluctuate. , The operating pressure and the capacity fluctuated.

Further, it is known that the non-azeotropic nature of the mixed refrigerant lowers the heat transfer coefficient in the heat exchanger piping as compared with a conventionally used single refrigerant such as R22. Therefore, there is also a problem that the COP (efficiency) of the refrigeration cycle is reduced.

In another conventional refrigeration cycle described above, for example, when applied to a separate type air conditioner in which the outdoor heat exchanger 3 and the indoor heat exchanger 5 are connected by an extension pipe, the extension pipe becomes longer. There has been a problem that hunting of the operating pressure and temperature of the refrigeration cycle occurs.

In another conventional refrigeration cycle, since the receiver 7 and the accumulator 6 are integrated,
Compared to a refrigeration cycle having only the accumulator 6,
There is a problem that a large volume is required and the unit becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Even when a non-azeotropic mixed refrigerant is used, the fluctuation of the composition of the circulating refrigerant due to the surplus refrigerant is suppressed, and the COP is improved. It is another object of the present invention to provide a refrigeration cycle that can prevent an increase in volume even if the accumulator is downsized and the accumulator and the receiver are integrated, and furthermore, prevent hunting and realize stable operation.

[0010]

A refrigerating cycle according to claim 1 of the present invention comprises: a compressor connected to a four-way valve via a pipe; a condenser connected to the four-way valve via a pipe; An evaporator connected to the four-way valve via a pipe, one to the four-way valve, the other to an accumulator connected to the compressor via a pipe, one to the condenser, and the other to the evaporator , A receiver having the accumulator therein, a first throttle device provided in a pipe between the receiver and the condenser, and a first throttling device provided between the receiver and the evaporator. A second throttle device provided in the tube.

[0011] The refrigeration cycle according to claim 2 of the present invention comprises:
The receiver is installed in the accumulator.

[0012] The refrigeration cycle according to claim 3 of the present invention comprises:
The receiver is provided at one of the upper part and the lower part of the accumulator, and is connected to the accumulator via a bypass pipe having a two-way valve.

[0013] The refrigeration cycle according to claim 4 of the present invention comprises:
A first temperature sensor installed on the condenser, a second temperature sensor installed on the outlet of the condenser, a third temperature sensor installed on the evaporator, and an outlet on the evaporator. A fourth temperature sensor, calculates a difference between a detected temperature of the first temperature sensor and a detected temperature of the second temperature sensor, and calculates the difference between the detected temperature and a first reference value set in advance. Compare,
The throttle amount of the first throttle device is controlled based on the comparison result, and the detected temperature of the fourth temperature sensor is compared with the third temperature.
Calculating the difference between the detected temperature of the temperature sensor and comparing the value with a preset second reference value, and controlling the aperture amount of the second aperture device based on the comparison result. Device control means.

[0014] A refrigeration cycle according to claim 5 of the present invention comprises:
The fourth temperature sensor is installed in a pipe between the compressor and the accumulator instead of installing the outlet of the evaporator, and the expansion device control means controls the compression when controlling the second expansion device. The difference between the detected temperature of the fourth temperature sensor installed in the pipe between the machine and the accumulator and the detected temperature of the third temperature sensor is calculated, and the difference is calculated with a third reference set in advance. Value, and based on the comparison result, the second
The aperture amount of the aperture device is controlled.

[0015] The refrigeration cycle according to claim 6 of the present invention comprises:
One of a compressor connected to the four-way valve via a pipe, an outdoor heat exchanger connected to the four-way valve via a pipe, and an indoor heat exchanger connected to the four-way valve via a pipe An accumulator connected to the four-way valve, the other being connected to a compressor via a pipe, one being connected to the outdoor heat exchanger, and the other being connected to the indoor heat exchanger via a pipe, and the accumulator being internally provided; A receiver having an outlet and an inlet / outlet pipe having a plurality of holes, being erected between the receiver and the accumulator and connected to a pipe from the outdoor heat exchanger,
A throttle device provided in a pipe between the receiver and the indoor heat exchanger.

[0016] The refrigeration cycle according to claim 7 of the present invention comprises:
The receiver provided with the inflow / outflow pipe is installed in an accumulator.

[0017] The refrigeration cycle according to claim 8 of the present invention comprises:
One of a compressor connected to the four-way valve via a pipe, an indoor heat exchanger connected to the four-way valve via a pipe, and an outdoor heat exchanger connected to the four-way valve via a pipe An accumulator, the other of which is connected to the compressor via a pipe, the other of which is connected to the indoor heat exchanger, and the other of which is connected to the outdoor heat exchanger via a pipe, to the top or inside, respectively. A receiver having the accumulator,
A first throttling device provided in a pipe between the receiver and the outdoor heat exchanger, a second throttling device provided in a pipe between the receiver and the indoor heat exchanger, and a defrost operation Liquid refrigerant control means for reducing the opening degree of the second expansion device at the end of the operation, and after a lapse of a predetermined time, fully closing the first expansion device to switch the four-way valve to a heating mode; And a non-azeotropic mixed refrigerant composed of two or more types of refrigerants different from each other.

A refrigeration cycle according to a ninth aspect of the present invention comprises:
When the operation is stopped, the first and second expansion devices are fully closed, and stop control means for stopping the driving of the compressor is provided.

In a refrigeration cycle according to a tenth aspect of the present invention, at the start of a heating operation, the four-way valve is set to a cooling mode to start the compressor, and after a lapse of a predetermined time, the opening degree of the first expansion device is reduced. And heating start control means for switching the four-way valve to a heating mode.

A refrigeration cycle according to claim 11 of the present invention includes a first temperature sensor installed at the outdoor heat exchanger, a second temperature sensor installed at an outlet of the outdoor heat exchanger, A fifth temperature sensor installed in a discharge pipe of the compressor, and when the temperature detected by the fifth temperature sensor exceeds a third reference value set in advance, fully open the second throttle device; Further, a difference between the detected temperature of the first temperature sensor and the detected temperature of the second temperature sensor is calculated, and the calculated value is compared with a first reference value set in advance. Diaphragm device control means for controlling the amount of diaphragm of the first diaphragm device.

A refrigeration cycle according to a twelfth aspect of the present invention includes a third temperature sensor installed in the indoor heat exchanger, a sixth temperature sensor installed in a suction pipe of the compressor, A pressure switch installed on the discharge pipe of the machine,
When the pressure switch exceeds a preset fourth reference value, the first throttle device is fully opened, and the detected temperature of the sixth temperature sensor and the detected temperature of the third temperature sensor are compared. A diaphragm device control means for calculating a difference, comparing the calculated value with a preset second reference value, and controlling a diaphragm amount of the second diaphragm device based on the comparison result. is there.

A refrigeration cycle according to a thirteenth aspect of the present invention is directed to a compressor connected to a four-way valve via a pipe, a condenser connected to the four-way valve via a pipe, and a pipe connected to the four-way valve. An evaporator connected to the evaporator, one is connected to the four-way valve, the other is connected to the compressor via a pipe, and the other is connected to the condenser, and the other is connected to the evaporator via the pipe. A receiver connected and having the accumulator on or inside, a first throttle device provided on a pipe between the receiver and the condenser, and a pipe provided between the receiver and the evaporator. A second throttle device, a sixth temperature sensor installed in a suction pipe of the compressor, and a fluctuation range of the detected temperature of the sixth temperature sensor calculated every predetermined time, and the fluctuation range is set in advance. Circulating when the sixth reference value is exceeded And a recognizing hunting determining means refrigerant is caused to hunting, but using a non-azeotropic refrigerant composed of two or more kinds of refrigerants having different boiling points in the refrigerant.

A refrigeration cycle according to a fourteenth aspect of the present invention includes a sixth temperature sensor installed in a suction pipe of a compressor;
A third temperature sensor installed in the evaporator, wherein the hunting determination unit changes the difference between the detected temperature of the sixth temperature sensor and the detected temperature of the third temperature sensor every predetermined time. The width is calculated, and when the fluctuation width exceeds a predetermined seventh reference value, it is recognized that the circulating refrigerant is hunting.

A refrigeration cycle according to a fifteenth aspect of the present invention includes a fifth temperature sensor installed in a discharge pipe of the compressor, and the hunting determining means determines the fifth temperature every predetermined time.
Of the temperature detected by the temperature sensor, and recognizes that the circulating refrigerant is hunting when the fluctuation exceeds a preset eighth reference value.

[0025] A refrigeration cycle according to claim 16 of the present invention comprises: a fifth temperature sensor installed in a discharge pipe of the compressor;
A first temperature sensor installed in the condenser, wherein the hunting determination unit changes a difference between a detected temperature of the fifth temperature sensor and a detected temperature of the first temperature sensor every predetermined time. The width is calculated, and when the fluctuation width exceeds a preset ninth reference value, it is recognized that the circulating refrigerant is hunting.

A refrigeration cycle according to a seventeenth aspect of the present invention is provided with a throttling device control means for increasing the degree of opening of the second throttling device when the hunting state is detected by the hunting judging means. .

[0027] The refrigeration cycle according to claim 18 of the present invention is provided with expansion device control means for increasing the opening of the first and second expansion devices when the hunting state is detected by the hunting determination means. Things.

A refrigeration cycle according to a nineteenth aspect of the present invention is provided with a bypass pipe having a two-way valve and a capillary tube between the accumulator and the receiver, wherein the hunting determination means detects a hunting state. A two-way valve control means for opening the two-way valve is provided.

A refrigeration cycle according to claim 20 of the present invention calculates a time constant of the circulation of the refrigerant according to a length of a pipe between a condenser and an evaporator connected through the receiver, A hunting suppressing means for suppressing hunting at a time interval equal to or longer than the time constant is provided.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. FIG. 1 is a block diagram illustrating a refrigeration cycle of, for example, an air conditioner according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view illustrating a configuration of a unit of the air conditioner according to Embodiment 1. Note that the refrigeration cycle of FIG. 1 shows a state during a cooling operation, and the same or corresponding parts as those of the related art described with reference to FIG.

In the drawing, reference numeral 4a denotes a first expansion device attached to a pipe connecting the outdoor heat exchanger 3 and a receiver 7 described later, and reference numeral 4b denotes a first expansion device attached to a pipe connecting the receiver 7 and the indoor heat exchanger 5. This is a second aperture device. Reference numeral 7 denotes the above-described receiver, which is disposed behind the compressor 1 as shown in FIG. 2 and in which an accumulator 6 is installed. The accumulator 6 is connected to a pipe from the suction side of the compressor 1 and a pipe from the four-way valve 2 that penetrate the upper part of the receiver 7 in a sealed state. In this refrigerating cycle, a non-azeotropic mixed refrigerant composed of two or more refrigerants having different boiling points is used.

Next, the operation during the cooling operation in the refrigeration cycle configured as described above will be described with reference to FIG. FIG. 3 is a Mollier chart during the cooling operation. Compressor 1
The gas refrigerant having a higher temperature and a higher pressure is discharged and enters the outdoor heat exchanger 3 through the four-way valve 2. The gas refrigerant exchanges heat with the outside air by the outdoor heat exchanger 3 to become a liquid refrigerant and enters the first expansion device 4a. The refrigerant that has entered the first expansion device 4a is decompressed to “A” shown in FIG. 3, becomes a high-temperature two-phase refrigerant having a dryness of 0.1 or less, and enters the receiver 7. Receiver 7
The low-dryness high-temperature two-phase refrigerant that has entered into the receiver 7 is cooled to a saturated liquid state of “b” shown in FIG. 3 by the low-temperature and low-pressure refrigerant flowing inside the accumulator 6 installed in the receiver 7. Outflow.

By this cooling, the enthalpy at the inlet of the indoor heat exchanger 5 is reduced, so that the enthalpy difference between the inlet and the outlet of the indoor heat exchanger 5 called the refrigerating effect is increased, and the characteristics of the non-azeotropic mixed refrigerant are as follows. Due to the known two-phase temperature glide, the lower the enthalpy at the inlet of the indoor heat exchanger 5, the higher the pressure at the inlet of the indoor heat exchanger 5 when maintaining the same evaporation temperature. For example, according to the experimental results of the present machine, the enthalpy difference between the entrance and exit of the indoor heat exchanger 5 is increased by 2% and the pressure at the entrance of the indoor heat exchanger 5 is increased by 9.8 kPa as compared with the above-described conventional case.

The saturated liquid refrigerant flowing out of the receiver 7 is
And becomes a low-temperature low-pressure two-phase refrigerant having a dryness of 0.2 to 0.3 and enters the indoor heat exchanger 5. The low-temperature and low-pressure two-phase refrigerant exchanges heat with indoor air by the indoor heat exchanger 5 to evaporate, and becomes a low-temperature and low-pressure two-phase refrigerant having a dryness of 0.9 to 1.0 through the four-way valve 2. Accumulator 6
to go into. The high-dryness, low-temperature, low-pressure two-phase refrigerant that has entered the accumulator 6 is heat-exchanged with the high-temperature, high-pressure two-phase refrigerant flowing through the receiver 7 as described above, and becomes a low-pressure gas refrigerant illustrated in FIG. Inhaled by machine 1. At this time, the surplus refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 as a saturated liquid refrigerant.

Here, the composition change of the surplus refrigerant will be described with reference to FIG. FIG. 4 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, respectively. If excess non-azeotropic refrigerant mixture is stored in the accumulator 6 of the conventional refrigeration cycle shown in FIG. 14, the composition of the refrigerant mixture becomes large because the pressure of the refrigerant mixture becomes low (see (a)). In the case of the embodiment, since the excess mixed refrigerant stored in the receiver 7 has a high pressure, the composition change of the mixed refrigerant circulating in the refrigeration cycle becomes small (see B).

As described above, according to the first embodiment, since the excess refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 in which the accumulator 6 is installed, the excess refrigerant is stored in the accumulator 6. Therefore, it is possible to suppress a change in the composition of the circulating refrigerant to be small, and it is possible to prevent the fluctuation of the operating pressure and the performance and the like.

As described above, since the excess refrigerant is prevented from accumulating in the accumulator 6, the compressor 1
The refrigerant sucked into the compressor can be surely gasified, thereby improving the efficiency of the compressor 1 and improving the COP of the refrigeration cycle.

As described above, the low-temperature, high-temperature two-phase refrigerant entering the receiver 7 is cooled to a saturated liquid state by the low-temperature, low-pressure refrigerant inside the accumulator 6 installed in the receiver 7. As a result, the enthalpy difference between the entrance and exit of the indoor heat exchanger 5 increases by 2%, the pressure at the entrance of the indoor heat exchanger 5 increases by 9.8 kPa, and as a result, the COP of the refrigeration cycle improves to 3.3%. There is an effect of doing.

Embodiment 2 FIG. 5 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 2 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the first embodiment described with reference to FIG. In the refrigeration cycle of this embodiment, a receiver 7 is installed in an accumulator 6, and two pipes penetrating the accumulator 6 in a sealed state are connected to the receiver 7. One of the tubes is connected to the outdoor heat exchanger 3 via the first expansion device 4a, and the other tube is connected to the indoor heat exchanger 5 via the second expansion device 4b.

Next, the operation during the cooling operation will be described with reference to the Mollier diagram of FIG. 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. The gas refrigerant exchanges heat with the outside air by the outdoor heat exchanger 3 to become a liquid refrigerant and enters the first expansion device 4a.
The refrigerant that has entered the first expansion device 4a is decompressed to “A” shown in FIG. 3, becomes a high-temperature two-phase refrigerant having a dryness of 0.1 or less, and enters the receiver 7. The low-dryness high-temperature two-phase refrigerant that has entered the receiver 7 is cooled to the saturated liquid state of “b” shown in FIG. 3 by the low-temperature and low-pressure refrigerant flowing inside the accumulator 6 surrounding the receiver 7. leak.

The saturated liquid refrigerant flowing out of the receiver 7 is
And becomes a low-temperature low-pressure two-phase refrigerant having a dryness of 0.2 to 0.3 and enters the indoor heat exchanger 5. The low-temperature and low-pressure two-phase refrigerant exchanges heat with indoor air by the indoor heat exchanger 5 to evaporate, and becomes a low-temperature and low-pressure two-phase refrigerant having a dryness of 0.9 to 1.0 through the four-way valve 2. Accumulator 6
to go into. The high-dryness, low-temperature, low-pressure two-phase refrigerant that has entered the accumulator 6 is heat-exchanged with the high-temperature, high-pressure two-phase refrigerant flowing through the receiver 7 as described above, and becomes a low-pressure gas refrigerant illustrated in FIG. Inhaled by machine 1. Also in this case, the surplus refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 as a saturated liquid refrigerant.

As described above, since the surplus refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 installed in the accumulator 6, the surplus refrigerant accumulates in the accumulator 6 as in the first embodiment. Gone
For this reason, it is possible to suppress a change in the composition of the circulating refrigerant to a small extent, and it is possible to prevent the fluctuation of the operating pressure and the performance and the like.

Further, as described above, since the excess refrigerant does not accumulate in the accumulator 6, the refrigerant sucked into the compressor 1 can be surely gasified, so that the efficiency of the compressor 1 is improved and the COP of the refrigeration cycle is improved. This has the effect of improving

The low-temperature high-temperature two-phase refrigerant entering the receiver 7 is supplied to the accumulator 6 surrounding the receiver 7.
The enthalpy difference between the entrance and exit of the indoor heat exchanger 5 is increased by exchanging heat with the low-temperature and low-pressure refrigerant inside the interior heat exchanger to cool to a saturated liquid state, and the pressure at the entrance of the indoor heat exchanger 5 rises. However, as a result, there is an effect that the COP of the refrigeration cycle can be improved.

Embodiment 3 FIG. FIG. 6 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 3 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the first embodiment described with reference to FIG. The refrigeration cycle of the present embodiment uses an upper container formed by a partition plate 9 provided at a substantially central portion of a pressure container 8 as an accumulator 6 and a lower container as a receiver 7. The receiver 7 provided below is provided with the bypass pipe 1 on which the two-way valve 10 is mounted.
1 connected. The two-way valve 10 is opened when the operation is stopped. Next, the operation during the cooling operation will be described with reference to the Mollier diagram of FIG. 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 as described above, becomes a liquid refrigerant, and enters the first expansion device 4a. This first
The refrigerant that has entered the expansion device 4a is decompressed to “a” shown in FIG. 3 and becomes a high-temperature two-phase refrigerant having a dryness of 0.1 or less and enters the receiver 7. The low-dryness high-temperature two-phase refrigerant that has entered the receiver 7 is separated by the low-temperature and low-pressure refrigerant flowing inside the accumulator 6 provided at the upper part through the partition plate 9 as shown in FIG.
Is cooled to the saturated liquid state of "b" and flows out of the receiver 7.

The low-temperature and low-pressure two-phase refrigerant having a dryness of 0.2 to 0.3 is formed by the second expansion device 4b, and the low-temperature and low-pressure two-phase refrigerant having a dryness of 0.9 to 1.0 is obtained by the indoor heat exchanger 5. It becomes a phase refrigerant and enters the accumulator 6 via the four-way valve 2. The high-temperature low-pressure low-pressure two-phase refrigerant entering the accumulator 6 is heat-exchanged with the high-temperature high-pressure two-phase refrigerant flowing inside the receiver 7 provided at the lower part via the partition plate 9, and “C” in FIG. ”And the compressor 1
Inhaled. The excess refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 as a saturated liquid refrigerant as described above, and when the two-way valve 10 is opened when the operation is stopped, the liquid refrigerant returned to the accumulator 6 Enters the receiver 7 via the bypass pipe 11.

In the third embodiment, since the surplus refrigerant generated during the circulation of the refrigerant is reliably stored in the receiver 7 provided below the accumulator 6, the change in refrigerant composition can be reduced similarly to the above-described embodiment. This makes it possible to prevent fluctuations in the operating pressure and performance, and to improve the efficiency of the compressor 1 and improve the COP of the refrigeration cycle.

The low-temperature, high-temperature two-phase refrigerant entering the receiver 7 is cooled to a saturated liquid state via the partition plate 9 by the low-temperature, low-pressure refrigerant inside the accumulator 6 provided above. Therefore, the enthalpy difference between the inlet and the outlet of the indoor heat exchanger 5 increases, and the pressure at the inlet of the indoor heat exchanger 5 increases.
There is an effect that can be improved.

When the operation is stopped, the two-way valve 10 is opened to allow the liquid refrigerant returned to the accumulator 6 to enter the receiver 7, so that the liquid refrigerant stored in the receiver 7 is immediately discharged to the room at the start of operation. It is possible to supply the heat to the heat exchanger 5, and there is also an effect that the rising performance can be improved.

In the third embodiment, the receiver 7
Is arranged below the accumulator 6, but a receiver 7 may be provided above the accumulator 6 to store the excess refrigerant of the saturated liquid refrigerant. FIG. 7 is a block diagram of a refrigeration cycle showing another embodiment of the third embodiment. In this embodiment, as described above, the upper container formed by the partition plate 9 provided substantially at the center of the pressure container 8 Is used as the receiver 7 and the lower container is used as the accumulator 6. In such a configuration, since the low-dryness high-temperature two-phase refrigerant entering the receiver 7 directly touches the partition plate 9, heat exchange with the low-temperature and low-pressure refrigerant flowing inside the accumulator 6 is efficient. It has the effect of being well performed.

Embodiment 4 FIG. FIG. 8 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 4 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the first embodiment described with reference to FIG. In the figure, reference numeral 12 denotes a first temperature sensor which is installed at the center of the outdoor heat exchanger 3 and detects the temperature Tc of the refrigerant cooled by the outdoor heat exchanger 3. Reference numeral 13 denotes a second temperature sensor which is provided at an outlet of the outdoor heat exchanger 3 and detects a temperature Tco of the refrigerant flowing out of the outdoor heat exchanger 3. Reference numeral 14 denotes a third temperature sensor which is installed at the center of the indoor heat exchanger 5 and detects the temperature Te of the refrigerant vaporized by the indoor heat exchanger 5.
Reference numeral 15 denotes a fourth temperature sensor which is provided at an outlet of the indoor heat exchanger 5 and has a temperature Te of the refrigerant flowing out of the indoor heat exchanger 5.
o is detected.

Reference numeral 21 denotes a control circuit for controlling, for example, the compressor 1 of the air conditioner, which includes the throttle device control means of the present invention.
For example, at the start of the cooling operation, the detected temperature Tco of the second temperature sensor 13 is subtracted from the detected temperature Tc of the first temperature sensor 12 to obtain the degree of supercooling SC at the outlet of the outdoor heat exchanger 3, and Cooling degree SC and first preset supercooling degree
When the supercooling degree SC is higher than the first reference value, the throttle opening of the first expansion device 4a is increased through the expansion device driving circuit 22 so that the supercooling degree SC becomes equal to the first cooling value. When the value is equal to or smaller than the reference value, the aperture of the first aperture device 4a is reduced.

The detected temperature T of the fourth temperature sensor 15
The superheat degree SH at the outlet of the indoor heat exchanger 5 is obtained by subtracting the detection temperature Te of the third temperature sensor 14 from eo, and the superheat degree SH and a second reference value of the preset superheat degree are calculated. When the superheat degree SH is higher than the second reference value, the throttle opening of the second expansion device 4b is increased through the expansion device drive circuit 22. When the superheat degree SH is equal to or less than the second reference value, The aperture of the second aperture device 4b is reduced.

Next, the operation of the refrigeration cycle configured as described above will be described with reference to FIG. FIG. 9 shows the fourth embodiment.
3 is a flowchart showing control of the first and second aperture devices according to the first embodiment, in which (a) is a control flowchart of the first aperture device and (b) is a control flowchart of the second aperture device. The operation of each unit when circulating the above-mentioned non-azeotropic mixed refrigerant is the same as that of the first embodiment, and therefore the description is omitted.

When the control circuit 21 starts the compressor 1, the control circuit 21
The temperature Tc of the two-phase refrigerant in the outdoor heat exchanger 3 is input through the first temperature sensor 12, and the temperature Tco of the refrigerant flowing out of the outdoor heat exchanger 3 is input through the second temperature sensor 13 ( S1, S2). Then, the detected temperature Tco is subtracted from the input detected temperature Tc to calculate the degree of supercooling SC at the outlet of the outdoor heat exchanger 3 (S3), and the calculated degree of supercooling SC and the previously set supercooling degree Is compared with the first reference value (S4). If the degree of supercooling SC is higher than the first reference value, the aperture opening of the first aperture device 4a is increased through the aperture device drive circuit 22 (S5). ), Supercooling degree S
When C is equal to or less than the first reference value, the first aperture device 4a
Of the throttle opening is reduced (S6).

Next, the temperature Te of the refrigerant vaporized by the indoor heat exchanger 5 is input via the third temperature sensor 14 and the temperature Te of the refrigerant flowing out of the indoor heat exchanger 5 is measured.
o is input through the fourth temperature sensor 15 (S11,
S12). Then, from the detected temperature Teo to the detected temperature T
e is subtracted to obtain the degree of superheat SH at the outlet of the indoor heat exchanger 5 (S13), and the obtained degree of superheat SH is compared with a preset second reference value of the degree of superheat (S14). When the degree of superheat SH is higher than the second reference value, the degree of opening of the second expansion device 4b is increased through the expansion device driving circuit 22 (S15). When the degree of superheat SH is equal to or less than the second reference value, The throttle opening of the second throttle device 4b is reduced (S1
6). The above-described first aperture device 4a and second aperture device 4
The control of b is repeatedly performed sequentially.

As described above, according to the fourth embodiment, the supercooling degree S obtained from the difference between the detected temperature Tc and the detected temperature Tco.
C, the throttle opening of the first throttle device 4a is controlled, and the throttle opening of the second throttle device 4b is determined based on the degree of superheat SH obtained from the difference between the detected temperature Teo and the detected temperature Te. Since the control is performed, the surplus refrigerant can be reliably stored in the receiver 7 without accumulating in the accumulator 6, and the composition change of the circulating refrigerant is suppressed even if the operating conditions such as the outside air temperature and the pipe length change. be able to.

Embodiment 5 FIG. In the present embodiment, the fourth temperature sensor 15 is installed, for example, on the suction side of the compressor 1 to detect its temperature, and the superheat degree of the suction of the compressor 1 is determined based on the difference from the detected temperature Te of the third temperature sensor 14. Is obtained, and a third preset
Of the second diaphragm device 4 in accordance with the result.
The aperture opening of b is controlled, and the same effect as in the fourth embodiment is achieved.

In the fourth and fifth embodiments, the first and second temperature sensors 1 and 2 are added to the refrigeration cycle of the first embodiment.
2 and 13 and the third and fourth temperature sensors 14 and 15 are respectively installed at predetermined positions to control the apertures of the first aperture device 4a and the second aperture device 4b, respectively. The temperature sensors may be installed in the refrigeration cycles of the second and third embodiments to control the degree of opening of the first expansion device 4a and the second expansion device 4b.

Embodiment 6 FIG. FIG. 10 shows Embodiment 6 of the present invention.
And FIG. 11 is an enlarged explanatory view of a receiver provided in the refrigeration cycle of the sixth embodiment. The refrigeration cycle shown in FIG. 10 shows a state during a cooling operation, and the same or corresponding parts as those in the first embodiment described with reference to FIG.

As in the first embodiment, the receiver 7 in the sixth embodiment has an accumulator 6 installed substantially at the center thereof, and an inflow / outflow pipe extending between the accumulator 6 and the accumulator 6 so that the tip of the receiver 7 protrudes from the liquid refrigerant. 16 is provided. As shown in FIG. 11, the inflow / outflow pipe 16 is provided with a plurality of holes 16a for allowing the liquid refrigerant inside the receiver 7 to flow out, and is connected to a pipe from the outdoor heat exchanger 3. The receiver 7 is connected to the indoor heat exchanger 5 via the expansion device 4.

Next, the operation of the sixth embodiment will be described. During the cooling operation, a 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. The gas refrigerant exchanges heat with the outside air by the outdoor heat exchanger 3 to become a high-temperature and high-pressure two-phase refrigerant and flows into the outflow / inflow pipe 16. This outflow / inflow pipe 1
The high-temperature and high-pressure two-phase refrigerant that has flowed into 6 flows out of the plurality of holes 16 a provided in the outflow / inflow pipe 16 and the tip portion, enters the receiver 7, and flows between the low-temperature and low-pressure refrigerant flowing inside the accumulator 6. Heat is exchanged to become a saturated liquid refrigerant, and flows out of the receiver 7. The subsequent operation is the same as in the first embodiment, and a description thereof will not be repeated.

Here, the flow of the refrigerant when the heating operation is started will be described. In this case, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 enters the indoor heat exchanger 5 through the four-way valve 2. At this time, since the indoor heat exchanger 5 operates as a condenser, the high-temperature and high-pressure gas refrigerant exchanges heat with indoor air to become a high-temperature and high-pressure liquid refrigerant and flows into the expansion device 4. The liquid refrigerant flowing into the expansion device 4 has a dryness of 0.2
As a low-temperature low-pressure two-phase refrigerant of about 0.3 enters the receiver 7, the gasified refrigerant enters and exits from the distal end of the inflow / outflow pipe 16, and the liquid refrigerant passes through a hole 16 a provided in the inflow / outflow pipe 16. In and out. This outflow stabilizes the liquid refrigerant in a state of being held in the receiver 7. Outflow / inflow pipe 16
The low-temperature and low-pressure two-phase refrigerant flowing out of the refrigerant enters the outdoor heat exchanger 3. Since the outdoor heat exchanger 3 operates as an evaporator, the refrigerant exchanges heat with the outside air and evaporates to a dryness of 0.9 to 1.0.
And enters the accumulator 6 via the four-way valve 2 and is sucked into the compressor 1. Also in this case, the excess refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 as a saturated liquid refrigerant.

As described above, since the generated surplus refrigerant is stored in the receiver 7, a change in the composition of the refrigerant circulating in the refrigeration cycle can be suppressed to a small extent. Since the plurality of holes 16a are provided, even when the two-phase refrigerant from the indoor heat exchanger 5 flows into the receiver 7, the refrigerant can be retained. There is no need to provide a throttling device between the outdoor heat exchanger 3 and an inexpensive refrigeration cycle.

Embodiment 7 FIG. FIG. 12 shows Embodiment 7 of the present invention.
13 is a block diagram showing a refrigeration cycle of, for example, an air conditioner, and FIG. 13 is an enlarged explanatory view of a receiver provided in the refrigeration cycle of the seventh embodiment. Note that the refrigeration cycle shown in FIG. 12 shows a state during cooling operation, and the same or corresponding parts as those in Embodiment 6 described in FIG. 12 are denoted by the same reference numerals and description thereof is omitted.

In the seventh embodiment, an inflow / outflow pipe 16 is provided in a receiver 7 installed in an accumulator 6. The inflow / outflow pipe 16 extends upward so that the distal end thereof protrudes from the liquid refrigerant in the same manner as in Embodiment 6 described above, and as shown in FIG. A hole 16a is provided and connected to a pipe on the outdoor heat exchanger 3 side. Note that the operation of this embodiment is the same as that of the sixth embodiment, and a description thereof is omitted. The effect is the same as that of the sixth embodiment.

Embodiment 8 FIG. FIG. 14 shows Embodiment 8 of the present invention.
FIG. 2 is a block diagram showing a refrigeration cycle of an air conditioner according to the present invention. Note that the refrigeration cycle in this figure shows a state during the heating operation, and the same or corresponding parts as those in Embodiment 4 described in FIG.

In this embodiment, the four-way valve drive circuit 25 and the opening degree of the second expansion device 4b are reduced at the end of the defrost operation, and after a predetermined time has elapsed, the first expansion device 4a is fully closed. A control circuit 21 having liquid refrigerant control means for switching the four-way valve 2 to the heating mode through the four-way valve drive circuit 25 is provided.

For example, during the heating operation, the second temperature sensor 1
When the occurrence of frost is detected through 3, the defrost operation is started. This defrost operation is performed when the outdoor heat exchanger 3 performs the heating operation under the condition where the outside air temperature is lower than 2 ° C.
When the temperature of the air becomes 0 ° C. or less and frost adheres to the surface, the operation is switched from the heating operation to the cooling operation, and the outdoor heat exchanger 3
This is an operation in which a high-temperature gas refrigerant is caused to flow to melt the frost.

During the defrost operation, the second temperature sensor 1
3 is compared with a preset fifth reference value (temperature value), and when the fifth reference value is higher, the defrost operation is continued, and the detected temperature Tco is higher than the fifth reference value.
Is higher, the defrost operation is terminated, the opening degree of the second expansion device 4b is reduced, and the process waits for a predetermined time. After a lapse of a predetermined time, the first throttle device 4a is fully closed, and the four-way valve drive circuit 25 is controlled to switch the four-way valve 2 to the heating mode.

Next, the operation of this embodiment will be described. First, the operation at the time of the heating operation will be described, and then the operation at the time of the defrost operation and the operation at the end of the operation will be described based on FIG. FIG. 15 is a flowchart showing the operation at the time of the defrost operation and at the time of the end of the operation. Note that the Mollier diagram during the heating operation is the same as the Mollier diagram during the cooling operation, and will be described with reference to FIG.

A high-temperature and high-pressure gas refrigerant is discharged from the compressor 1 and enters the indoor heat exchanger 5 through the four-way valve 2. The gas refrigerant exchanges heat with indoor air by the indoor heat exchanger 5 to become a liquid refrigerant and enters the second expansion device 4b. This second
The refrigerant that has entered the expansion device 4b is decompressed to “a” shown in FIG. 3 and becomes a high-temperature two-phase refrigerant having a dryness of 0.1 or less and enters the receiver 7. The low-dryness high-temperature two-phase refrigerant that has entered the receiver 7 is cooled to the “b” saturated liquid state shown in FIG. 3 by the low-temperature and low-pressure refrigerant flowing inside the accumulator 6 installed above the receiver 7. It flows out of the receiver 7.

The saturated liquid refrigerant flowing out of the receiver 7 is
And becomes a low-temperature low-pressure two-phase refrigerant having a dryness of 0.2 to 0.3 and enters the outdoor heat exchanger 3. The low-temperature and low-pressure two-phase refrigerant exchanges heat with outdoor air by the outdoor heat exchanger 3 and evaporates, and becomes a low-temperature and low-pressure two-phase refrigerant having a dryness of 0.9 to 1.0 through the four-way valve 2. Accumulator 6
to go into. The high-dryness, low-temperature, low-pressure two-phase refrigerant that has entered the accumulator 6 is heat-exchanged with the high-temperature, high-pressure two-phase refrigerant flowing through the receiver 7 as described above, and becomes a low-pressure gas refrigerant illustrated in FIG. Inhaled by machine 1. At this time, the surplus refrigerant generated during the circulation of the refrigerant is stored in the receiver 7 as a saturated liquid refrigerant.

During the heating operation, the control circuit 21 monitors through the second temperature sensor 13 whether or not frost is generated in the outdoor heat exchanger 3, and detects the occurrence of frost from the second temperature sensor 13. When the defrost operation is performed, that is, the four-way valve 2
Is driven to switch to the cooling mode so that a high-temperature gas refrigerant flows through the outdoor heat exchanger 3 (S21). The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

When the defrost operation is started, the detected temperature Tco of the second temperature sensor 13 is compared with a preset fifth reference value (S22, S23), and the fifth reference value is higher. At this time, the defrost operation is continued, and when the detected temperature Tco becomes higher than the fifth reference value, it is determined that the frost generated in the outdoor heat exchanger 3 has been melted by the high-temperature gas refrigerant, and the defrost operation is ended (S24). ). At this time, the second
Then, the opening degree of the expansion device 4b is reduced and the operation waits for a predetermined time (S25, S26). When the predetermined time has elapsed, the first expansion device 4a is fully closed (S27), and the four-way valve drive circuit 25 is controlled to switch the four-way valve 2 to the heating mode (S28). After that, the first and second aperture devices 4a,
4b is controlled normally (S29).

As described above, according to the eighth embodiment, when the defrosting operation is completed, the opening degree of the second expansion device 4b is reduced to wait for a predetermined time, and then the first expansion device 4a
Is fully closed to hold the liquid refrigerant in the receiver 7, and then
Since the four-way valve 2 is controlled to switch to the heating mode, the amount of liquid refrigerant returning to the accumulator 6 when the refrigerant circuit is switched from the defrost circuit (cooling operation) to the heating circuit (heating operation) can be reduced. Therefore, there is an effect that the volume of the accumulator 6 can be reduced. In addition, after returning to the heating operation, the liquid refrigerant held in the receiver 7 can be quickly supplied to the outdoor heat exchanger 3 serving as an evaporator, so that there is an effect that the startup performance of the operation is improved.

Embodiment 9 FIG. 16 shows a ninth embodiment of the present invention.
FIG. 2 is a block diagram showing a refrigeration cycle of an air conditioner according to the embodiment. Note that the refrigeration cycle in this figure shows a state during cooling operation, and the same or corresponding parts as those in Embodiment 8 described in FIG.

In the present embodiment, when the operation stop command is input by, for example, an external operation, the compressor drive circuit 26
A control circuit 21 having stop control means for closing the first and second expansion devices 4a and 4b fully and stopping driving of the compressor 1 through the compressor drive circuit 26 is provided.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 17 shows the first and second embodiments in the ninth embodiment.
6 is a flowchart showing control of the aperture device of FIG. In addition,
The operation of each part when the non-azeotropic mixed refrigerant is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. When the control circuit 21 receives the operation stop command during the cooling operation, as described above, the throttle device driving circuit 2
2, the first and second expansion devices 4a, 4b are fully closed, and the driving of the compressor 1 is stopped through the compressor driving circuit 26 (S31, S32, S33).

As described above, according to the ninth embodiment, when the operation stop command is received, the first throttle device 4a and the second throttle device 4b are fully closed, and the driving of the compressor 1 is stopped. As a result, the excess refrigerant can be held in the receiver 7, so that the amount of liquid refrigerant returning to the accumulator 6 when the compressor 1 is stopped can be reduced, and even if the volume of the accumulator 6 is reduced. In addition, it is possible to prevent the flow of the liquid refrigerant into the compressor 1 and to prevent a starting failure when the operation is started again. Further, when the operation is started again, the liquid refrigerant held in the receiver 7 can be promptly supplied to the indoor heat exchanger 5, so that there is an effect that the start-up performance of the operation is improved. In the present embodiment, the cooling operation has been described, but it is needless to say that the present invention can be applied to the case where the heating operation is stopped.

Embodiment 10 FIG. FIG. 18 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 10 of the present invention. The refrigeration cycle in this figure shows the state during the cooling operation as described above, and the same or corresponding parts as those in the eighth embodiment described with reference to FIG.

In this embodiment, for example, when a heating operation command is input by an external operation, the four-way valve 2 is set to the cooling mode to start the compressor 1, and after a lapse of a predetermined time, the first throttle device 4a is opened. A control circuit 21 having heating start control means for reducing the degree and switching the four-way valve 2 to the heating mode is provided. The above-described predetermined time is, for example, about 30 seconds to 1 minute, and this is for storing the liquid refrigerant accumulated in the outdoor heat exchanger 3 in the receiver 7.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 19 is a flowchart showing control of the four-way valve, the first and second throttle devices in the tenth embodiment. In addition, operation | movement of each part when circulating a non-azeotropic mixed refrigerant | coolant at the time of cooling operation, and a Mollier diagram at the time of cooling operation (FIG. 3)
The change in the composition of the surplus refrigerant is the same as that in the first embodiment, and thus the description thereof will be omitted.

Upon receiving the heating operation command, the control circuit 21 switches the four-way valve 2 to the cooling mode through the four-way valve drive circuit 25, starts the compressor 1 through the compressor drive circuit 26, and waits for a predetermined time. (S41-S4
3). At this time, the gas refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 3, pushes out the liquid refrigerant in the outdoor heat exchanger 3 cooled by the outside air during stoppage, and enters the receiver 7.
When a predetermined time has elapsed since the start of the compressor 1, the opening degree of the first expansion device 4a is reduced through the expansion device drive circuit 22 (S44), and the four-way valve 2 is switched to the heating mode (S45). Thereafter, the first aperture device 4a is controlled normally (S46).

As described above, according to the tenth embodiment, when a heating operation command is received, the mode is switched to the cooling mode for a predetermined time, and the liquid refrigerant accumulated in the outdoor heat exchanger 3 is stored in the receiver 7. After that, the first diaphragm device 4a
Is switched to the heating mode by reducing the opening of the accumulator 6, so that a large amount of liquid refrigerant accumulated in the outdoor heat exchanger 3 does not enter the accumulator 6 at the start of the heating operation. There is an effect that the volume can be reduced.

Embodiment 11 FIG. FIG. 20 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 11 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the fourth embodiment described with reference to FIG.

In the present embodiment, when the fifth temperature sensor 16 installed in the discharge pipe of the compressor 1 and the detected temperature Td of the fifth temperature sensor 16 exceed a third reference value set in advance. The second expansion device 4b is fully opened, and the difference between the detected temperature Tc of the first temperature sensor 12 and the detected temperature Tco of the second temperature sensor 13 is calculated. And a control circuit 21 having aperture device control means for controlling the aperture amount of the first aperture device 4a based on the comparison result.

Next, the operation of the present embodiment will be described with reference to FIG. FIG. 21 is a flowchart showing control of the first and second aperture devices in the eleventh embodiment. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

During the cooling operation, the control circuit 21 determines the temperature Td of the gas refrigerant discharged from the compressor 1 with the fifth temperature sensor 1
6, the temperature Tc of the two-phase refrigerant in the outdoor heat exchanger 3 via the first temperature sensor 12, and the refrigerant flowing out of the outdoor heat exchanger 3 via the second temperature sensor 13. (T51 to S5)
3) First, the detected temperature Tco is subtracted from the detected temperature Tc to calculate the degree of supercooling SC at the outlet of the outdoor heat exchanger 3 (S5).
4), comparing with a first reference value set in advance (S5)
5). When the degree of supercooling SC is higher, the first expansion device 4
The throttle opening of the device 4a is reduced (S56), and when the first reference value is higher, the throttle opening of the device 4a is reduced (S56).
57). When the first expansion device 4a is controlled, the detection temperature Td of the fifth temperature sensor 16 (the discharge temperature T of the compressor 1)
When d) exceeds a third reference value preset as an operation upper limit, the second throttle device 4b is fully opened (S58, S58).
59) If the detected temperature Td of the fifth temperature sensor 16 is equal to or lower than the third reference value, the second throttle device 4b is controlled normally (S58, S60).

Here, changes in the temperature Td and the COP (efficiency) when the opening degree of the first expansion device 4a and the second expansion device 4b are changed will be described with reference to FIG. FIG.
FIG. 19 is a graph showing changes in opening degrees of a first expansion device and a second expansion device and discharge temperatures Td and COP of a compressor according to an eleventh embodiment. According to this, the discharge temperature Td of the compressor 1
It can be seen that, when the degree of opening of the second throttle device 4b is increased, the value greatly decreases. On the other hand, it can be seen that the COP decreases as the size of the first aperture device 4a increases. Therefore, when the discharge temperature Td exceeds the third reference value, the second expansion device 4b is fully opened to return the excess refrigerant in the receiver 7 to the accumulator 6 to lower the discharge temperature Td, thereby reducing the excess temperature. When the cooling degree SC decreases and becomes lower than the first reference value, the opening degree of the first expansion device 4a is reduced.

According to the eleventh embodiment, as described above, when the discharge temperature Td exceeds the third reference value, the second expansion device 4b is fully opened to remove excess refrigerant in the receiver 7. Returning to the accumulator 6, the discharge temperature Td is lowered, and when the supercooling degree SC falls and becomes lower than the first reference value, the opening degree of the first expansion device 4a is reduced. There is an effect that the decrease in the temperature can be suppressed as much as possible.

Embodiment 12 FIG. FIG. 23 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 12 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the fourth embodiment described with reference to FIG.

In the present embodiment, the sixth temperature sensor 17 installed on the suction pipe of the compressor 1, the pressure switch 24 installed on the discharge pipe of the compressor 1, and the second temperature sensor 17 When the reference value exceeds 4, the first aperture device 4
a is fully opened, the detected temperature Ts of the sixth temperature sensor 17 is compared with the detected temperature Te of the third temperature sensor 14, and the throttle amount of the second throttle device 4b is controlled based on the comparison result. And a control circuit 21 having an aperture control unit.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 24 is a flowchart showing control of the first and second aperture devices in the twelfth embodiment. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

During the cooling operation, the control circuit 21 inputs the pressure Pd of the gas refrigerant discharged from the compressor 1 through the pressure switch 24, and inputs the pressure Pd of the gas refrigerant into the indoor heat exchanger 5 through the third temperature sensor 12. And the temperature T of the refrigerant sucked into the compressor 1 via the sixth temperature sensor 17.
s is input (S71 to S73), and firstly, the detected temperature Te is subtracted from the detected temperature Ts to calculate the suction superheat degree SHs of the compressor 1 (S74). A comparison is made (S75). If the degree of suction superheat SHs is higher, the throttle opening of the second throttle device 4b is increased through the throttle device drive circuit 22 (S76). If the second reference value is higher, the throttle of the device 4b is reduced. The opening is reduced (S77). If the detected pressure Pd of the pressure switch 24 (the discharge pressure Pd of the compressor 1) exceeds a fourth reference value set in advance when controlling the opening degree of the second throttle device 4b, the throttle device is driven. The first diaphragm device 4a through the circuit 22
Is fully opened (S78, S79), and when the fourth reference value is higher, the device 4a is controlled normally (S78, S8).
0).

Here, changes in the pressures Pd and COP when the opening degrees of the first throttle device 4a and the second throttle device 4b are changed will be described with reference to FIG. FIG. 25 is a graph showing changes in the opening degrees of the first throttle device and the second throttle device and the discharge pressures Pd and COP of the compressor according to the twelfth embodiment. According to this, the discharge pressure Pd of the compressor 1 decreases greatly when the opening degree of the first expansion device 4a is increased, and
It can be seen that when the degree of opening of the throttle device 4b is reduced, it decreases. On the other hand, it can be seen that the COP increases when the second throttle device 4b is reduced. Therefore, when the discharge pressure Pd exceeds the fourth reference value, the first expansion device 4a is fully opened to lower the discharge pressure Pd, thereby lowering the suction superheat degree SHs to the second reference value or less. , The opening degree of the second expansion device 4b is reduced.

As described above, according to Embodiment 12, when the discharge pressure Pd exceeds the fourth reference value, the first expansion device 4a is fully opened to lower the discharge pressure Pd, as described above. As a result, when the degree of suction superheat SHs falls below the second reference value, the opening degree of the second expansion device 4b is reduced, so that the reduction of the COP can be suppressed as much as possible.

In the following embodiments, determination of hunting occurring in the refrigeration cycle and suppression of hunting will be described. For example, when the refrigeration cycle configured as shown in FIG. 23 is applied to a separate type air conditioner in which the outdoor heat exchanger 3 and the indoor heat exchanger 5 are connected by extension piping, the amount of excess refrigerant is increased due to the extension of the piping. The temperature of the refrigerant decreases, and the superheated gas refrigerant flows into the accumulator 6 to increase the temperature of the refrigerant therein. In such a case, the accumulator 6
The temperature difference between the receiver 7 and the receiver 7 becomes smaller, the amount of heat exchange decreases, and the pressure inside the receiver 7 increases.

When the pressure inside the receiver 7 rises, the amount of refrigerant flowing out of the receiver 7 increases, and a large amount of refrigerant flows into the accumulator 6, so that the degree of superheat of the gas refrigerant flowing into the accumulator 6 decreases, and The refrigerant temperature in 6 decreases.

When the temperature of the refrigerant in the accumulator 6 decreases, the temperature difference between the accumulator 6 and the receiver 7 increases, conversely, the amount of heat exchange increases, and the pressure inside the receiver 7 decreases.

When the pressure inside the receiver 7 decreases, the amount of refrigerant flowing out of the receiver 7 decreases, and the accumulator 6
The amount of the refrigerant flowing into the accumulator 6 decreases, and the superheated gas refrigerant flows into the accumulator 6 again, so that the temperature of the refrigerant inside the gas refrigerant rises.

When the length of the extension pipe becomes longer and the surplus refrigerant amount decreases, the temperature of the refrigerant flowing into the accumulator 6 and the pressure in the receiver 7 fluctuate, and hunting occurs. For example, according to the experimental results of the present refrigeration cycle, in the cooling operation, when the extension pipe is 5 m, the refrigeration cycle is operated stably, but when the extension pipe is 50 m, the refrigeration cycle is in a hunting state, and It has been confirmed that the suction temperature Ts and the suction superheat SHs fluctuate by 10 ° C. or more.

Embodiment 13 FIG. FIG. 26 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 13 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the fourth embodiment described with reference to FIG.

In the present embodiment, the fluctuation range of the sixth temperature sensor 17 installed in the suction pipe of the compressor 1 and the fluctuation range of the detection temperature Ts of the sixth temperature sensor 17 at predetermined time intervals are calculated. And a control circuit 21 having hunting determination means for recognizing that the circulating refrigerant is hunting when the pressure exceeds a preset sixth reference value. Although the control circuit 21 in the drawing includes a diaphragm device control means for controlling the first and second diaphragm devices 4a and 4b through the diaphragm device driving circuit 22, here, only hunting determination is performed.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 27 is a flowchart illustrating a hunting determination in the refrigeration cycle of the thirteenth embodiment. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

When the compressor 1 is started to start the cooling operation, the control circuit 21 inputs the temperature Ts of the gas refrigerant on the suction side of the compressor 1 (S91), and subtracts Tsb from the temperature Ts. The fluctuation width ΔTs is calculated (S92). The value of Tsb is set to zero or a predetermined value as an initial value. When the fluctuation width ΔTs is calculated, the fluctuation width ΔTs
Is compared with a sixth reference value of a preset fluctuation range (S93), and when the sixth reference value is larger, it is determined that hunting has not occurred in the refrigeration cycle, and the input is performed. The temperature Ts is set as Tsb (S98). After a lapse of a predetermined time, the temperature Ts is input again, and the above-described operation is repeated.

On the other hand, if the absolute value ΔTs is larger than the sixth reference value, it is determined that hunting may occur, and ΔTs is determined.
It is determined whether s is multiplied by ΔTsb and is less than zero, that is, whether the sign of the multiplied value is “+” or “−” (S94). If the sign of the multiplied value is “+”, it is determined that there is no change in the circulating refrigerant, and it is determined whether or not the count value exceeds a preset tenth reference value (S96). Is "-", it is determined that there is a change in the circulating refrigerant, "1" is added to the count value (S95), and it is determined whether the count value exceeds the tenth reference value (S95).
96). If the count value does not exceed the tenth reference value, the calculated temperature fluctuation width ΔTs is set as ΔTsb (S97), and then the input temperature Ts is set as Tsb (S98). After a lapse of a predetermined time, the temperature Ts is input again, and the above-described operation is repeated. If the count value exceeds the tenth reference value, it is determined that hunting has occurred in the refrigeration cycle (S9).
9).

As described above, according to the thirteenth embodiment, the temperature Ts of the gas refrigerant on the suction side of the compressor 1 is input at predetermined time intervals.
sb is subtracted to calculate a fluctuation width {Ts, and this fluctuation width}
The absolute value of Ts is compared with the sixth reference value, and the absolute value △ Ts
Is larger, ΔTs is multiplied by ΔTsb to determine whether it is less than zero. If the multiplied value is less than zero, it is determined that the circulating refrigerant has a change, and “1” is added to the count value. Since it is determined that hunting has occurred when the count value exceeds the tenth reference value, it is possible to accurately monitor whether or not hunting has occurred in the refrigeration cycle.

Embodiment 14 FIG. FIG. 28 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 14 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the fourth embodiment described with reference to FIG.

This embodiment is different from the third embodiment in that the third temperature sensor 14 installed in the indoor heat exchanger 5 and the sixth temperature sensor 17 installed in the suction pipe of the compressor 1 A fluctuation range of a difference between the detection temperature Ts of the temperature sensor 17 and the detection temperature Te of the third temperature sensor 14 is calculated, and when the fluctuation range exceeds a preset seventh reference value, the circulating refrigerant is reduced. A control circuit 21 having hunting determination means for recognizing that hunting is occurring is provided. The control circuit 21 shown in FIG.
And a diaphragm control means for controlling the second diaphragms 4a and 4b, but here, only hunting determination is performed.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 29 is a flowchart showing a hunting determination in the refrigeration cycle of the fourteenth embodiment. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

When the compressor 1 is started and the cooling operation is started, the control circuit 21 inputs the temperature Te of the two-phase refrigerant in the indoor heat exchanger 5 via the third temperature sensor 14 and
The temperature Ts of the gas refrigerant on the suction side of the compressor 1 is input via the sixth temperature sensor 17 (S101, S102). Next, the temperature Te is subtracted from the temperature Ts, and the difference S
Hs is calculated, and SHs is calculated from the calculated temperature SHs.
The variation width ΔSHs of the temperature SHs is calculated by subtracting b (S103, S104). The value of the SHsb is set to zero or a predetermined value as an initial value as described above. After calculating the fluctuation width ΔSHs, the absolute value of the fluctuation width ΔSHs is compared with a preset seventh reference value (S105). If the seventh reference value is larger,
It is determined that hunting has not occurred in the refrigeration cycle, and the temperature SHs of the subtraction value is set as SHsb (S
110). After a lapse of a predetermined time, the temperature T
The operation described above is repeated by inputting e and Ts, respectively.

On the other hand, when the absolute value △ SHs is larger than the seventh reference value, it is determined that hunting is likely to occur.
SHs is multiplied by △ SHsb to determine whether it is less than zero, that is, whether the sign of the multiplied value is “+” or “−” (S10).
6). If the sign of the multiplication value is “+”, it is determined that there is no change in the circulating refrigerant, and it is determined whether the count value exceeds a preset tenth reference value (S10).
8) If the sign is "-", it is determined that there is a change in the circulating refrigerant, and "1" is added to the count value (S10).
7) It is determined whether or not the count value exceeds a tenth reference value (S108). If the count value does not exceed the tenth reference value, the calculated fluctuation range of the temperature △
SHs is set as △ SHsb (S109), and then SHs of the temperature difference is set as SHsb (S11).
0). After a lapse of a predetermined time, the temperatures Te, T
s is input, and the above operation is repeated. Also,
When the count value exceeds the tenth reference value, it is determined that hunting has occurred in the refrigeration cycle (S1).
11).

As described above, according to the fourteenth embodiment, the temperature Te of the two-phase refrigerant in the indoor heat exchanger 5 and the temperature Ts of the gas refrigerant on the suction side of the compressor 1 are input at predetermined time intervals. When the temperatures Te and Ts are input, the temperature Te is changed from the temperature Ts to the temperature Te.
Is subtracted to calculate the difference temperature SHs, and SHsb is subtracted from the calculated temperature SHs to calculate the temperature SHs.
Is calculated, and the absolute value of the variation ΔSHs is compared with a seventh reference value. If the absolute value ＨSHs is larger, multiply △ SHs by △ SHsb to determine whether the difference is less than zero. Is determined, and when the multiplication value is less than zero, it is determined that there is a change in the circulating refrigerant, and “1” is added to the count value. When the count value exceeds the tenth reference value, hunting has occurred. Thus, it is possible to accurately monitor whether or not hunting has occurred in the refrigeration cycle.

Embodiment 15 FIG. FIG. 30 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 15 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the fourth embodiment described with reference to FIG.

In this embodiment, the fluctuation range of the fifth temperature sensor 16 installed in the discharge pipe of the compressor 1 and the fluctuation range of the detected temperature Td of the fifth temperature sensor 16 at predetermined time intervals are calculated. And a control circuit 21 having hunting determination means for recognizing that the circulating refrigerant is hunting when the pressure exceeds a preset eighth reference value. Although the control circuit 21 in the drawing includes a diaphragm device control means for controlling the first and second diaphragm devices 4a and 4b through the diaphragm device driving circuit 22, here, only hunting determination is performed.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 31 is a flowchart showing the hunting determination in the refrigeration cycle of the fifteenth embodiment. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

When starting the compressor 1 and starting the cooling operation, the control circuit 21 inputs the temperature Td of the gas refrigerant on the discharge side of the compressor 1 via the fifth temperature sensor 16 (S12).
1), Tdb is subtracted from the temperature Td, and the fluctuation width ΔTd
Is calculated (S122). The value of Tdb is set to zero or a predetermined value as an initial value as described above. After calculating the fluctuation width ΔTd, the absolute value of the fluctuation width ΔTd is compared with a preset eighth reference value of the fluctuation width (S123). If the eighth reference value is larger, the freezing is performed. Judging that no hunting has occurred in the cycle,
The input temperature Td is set as Tdb (S128). After a lapse of a predetermined time, the temperature Td is input again, and the above-described operation is repeated.

On the other hand, when the absolute value ΔTd is larger than the eighth reference value, it is determined that hunting may occur, and ΔTd is determined.
It is determined whether d is multiplied by △ Tdb and is less than zero, that is, whether the sign of the multiplied value is “+” or “−” (S124). If the sign of the multiplication value is “+”, it is determined that there is no change in the circulating refrigerant, and it is determined whether the count value exceeds a preset tenth reference value (S126). Is "-", it is determined that there is a change in the circulating refrigerant, "1" is added to the count value (S125), and it is determined whether the count value exceeds the tenth reference value (S126). ). When the count value does not exceed the tenth reference value, the calculated temperature fluctuation width ΔTd is calculated as ΔTd
b (S127), and then the input temperature Td is set to T
db (S128). After a lapse of a predetermined time, the temperature Td is input again, and the above-described operation is repeated. When the count value exceeds the tenth reference value, it is determined that hunting has occurred in the refrigeration cycle (S129).

As described above, according to the fifteenth embodiment, the temperature Td of the gas refrigerant on the discharge side of the compressor 1 is input at predetermined time intervals.
db is subtracted to calculate a fluctuation width {Td, and this fluctuation width}
The absolute value of Td is compared with the eighth reference value, and the absolute value △ Td
Is larger than △ Tdb, it is determined whether the value is less than zero by multiplying △ Td by △ Tdb. If the multiplied value is less than zero, it is determined that the circulating refrigerant has a change, and “1” is added to the count value. Since it is determined that hunting has occurred when the count value exceeds the tenth reference value, it is possible to accurately monitor whether or not hunting has occurred in the refrigeration cycle.

Embodiment 16 FIG. FIG. 32 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 16 of the present invention. Note that the refrigeration cycle in this figure shows a state during a cooling operation, and the same or corresponding parts as those in the fourth embodiment described with reference to FIG.

In the present embodiment, the first temperature sensor 12 installed in the outdoor heat exchanger 3, the fifth temperature sensor 16 installed in the discharge pipe of the compressor 1, and the hunting determination means
The fluctuation range of the difference between the detected temperature Td of the fifth temperature sensor 16 and the detected temperature Tc of the first temperature sensor 12 is calculated at predetermined time intervals, and the fluctuation range exceeds a preset ninth reference value. And a control circuit 21 having hunting determination means for recognizing that the circulating refrigerant is causing hunting when the circulating refrigerant occurs. The control circuit 21 shown in FIG. 1 controls the first and second aperture devices 4a and 4b through an aperture device drive circuit 22.
Is provided, but here, only hunting determination is performed.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 33 is a flowchart showing the hunting determination in the refrigeration cycle of the sixteenth embodiment. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

When the compressor 1 is started and the cooling operation is started, the control circuit 21 inputs the temperature Td of the gas refrigerant on the discharge side of the compressor 1 via the fifth temperature sensor 16 and
The temperature Tc of the refrigerant cooled by the outdoor heat exchanger 3 is set to the first
(S131, S13)
2). Next, the temperature Tc is subtracted from the temperature Td to calculate the difference SHd, and the difference SHdb is subtracted from the calculated temperature SHd to change the temperature SHd by a variation width ΔSHd.
Is calculated (S133, S134). The SHd
The value of b is set to zero or a predetermined value as an initial value as described above. After calculating the fluctuation width ΔSHd, the absolute value of the fluctuation width ΔSHd is compared with a preset ninth reference value (S135). If the ninth reference value is larger, hunting occurs in the refrigeration cycle. It is determined that it has not been performed, and the temperature SHd of the subtraction value is set as SHdb (S140). After a lapse of a predetermined time, the temperatures Td and Tc are input again, and the above-described operation is repeated.

On the other hand, when the absolute value △ SHd is larger than the ninth reference value, it is determined that hunting may occur, and
SHd is multiplied by △ SHdb to determine whether the value is less than zero, that is, whether the sign of the multiplied value is “+” or “−” (S13).
6). If the sign of the multiplication value is “+”, it is determined that the circulating refrigerant does not fluctuate, and it is determined whether the count value exceeds a preset tenth reference value (S13).
8) If the sign is "-", it is determined that there is a change in the circulating refrigerant, and "1" is added to the count value (S13).
7) It is determined whether or not the count value exceeds the tenth reference value (S138). If the count value does not exceed the tenth reference value, the calculated fluctuation range of the temperature △
SHd is set as △ SHdb (S139), and then SHd of the temperature difference is set as SHdb (S14).
0). After a lapse of a predetermined time, the temperatures Td, T
The above-mentioned operation is repeated by inputting c respectively. Also,
When the count value exceeds the tenth reference value, it is determined that hunting has occurred in the refrigeration cycle (S1).
41).

As described above, according to the sixteenth embodiment, the temperature Td of the gas refrigerant on the discharge side of the compressor 1 and the temperature of the outdoor heat exchanger 3
When the temperature Tc of the refrigerant cooled by the temperature is input at predetermined time intervals, and when the temperatures Td and Tc are input, the temperature Td is subtracted from the temperature Td to calculate the difference temperature SHd and calculate the calculated temperature SHd. By subtracting SHdb from SHd, a fluctuation width ΔSHd of the temperature SHd is calculated, and this fluctuation width ΔSH is calculated.
The absolute value of d is compared with the ninth reference value, and the absolute value △ SHd
Is larger than ゼ ロ SHd and △ SHdb to determine whether it is less than zero. If the multiplied value is less than zero, it is determined that the circulating refrigerant has a change, and “1” is added to the count value. Since it is determined that hunting has occurred when the count value exceeds the tenth reference value, it is possible to accurately monitor whether or not hunting has occurred in the refrigeration cycle.

Embodiment 17 FIG. This embodiment relates to a control for suppressing the occurrence of hunting in the refrigeration cycle, and will be described with reference to FIG. 26 shown in Embodiment 13, for example.

The control circuit 21 according to the present embodiment includes, for example, the hunting determination means shown in the thirteenth embodiment and an aperture device for controlling the aperture amount of the second aperture device 4b through the aperture device drive circuit 22 when hunting is detected. Control means.

Next, the operation of the seventeenth embodiment will be described with reference to FIG. FIG. 34 is a flowchart showing control of the second aperture device according to Embodiment 17 of the present invention. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

During the cooling operation, the control circuit 21 inputs the temperature Ts of the gas refrigerant on the suction side of the compressor 1 at predetermined time intervals, and monitors whether or not hunting has occurred in the refrigeration cycle each time. When the hunting is detected (S151), the opening degree of the second aperture device 4b is increased through the aperture device drive circuit 22 (S152). At this time, the surplus refrigerant stored in the receiver 7 moves to the accumulator 6 and suppresses a change in the refrigerant temperature in the accumulator 6.

As described above, according to the seventeenth embodiment, when hunting is detected, the degree of opening of the second expansion device 4b is increased, and the excess refrigerant stored in the receiver 7 is moved to the accumulator 6 and Since the fluctuation of the refrigerant temperature in 6 is suppressed, there is an effect that hunting occurring in the refrigeration cycle can be suppressed.

In the present embodiment, the control for suppressing the hunting when the hunting is detected by the hunting determining means shown in the thirteenth embodiment has been described.
When hunting is detected by the hunting determination means according to any one of the fourth to sixteenth embodiments, the opening degree of the second expansion device 4b may be increased to suppress the hunting.

Embodiment 18 FIG. This embodiment is another embodiment of the above-described embodiment 17, and will be described with reference to FIG. Control circuit 21 of the present embodiment
The hunting determination means shown in the thirteenth embodiment and the iris driving circuit 2 when hunting is detected
2. A diaphragm control means for controlling the amount of diaphragm of the first and second diaphragms 4a and 4b through the second diaphragm unit 2.

Next, the operation of the eighteenth embodiment will be described with reference to FIG. FIG. 35 is a flowchart showing control of the first and second aperture devices according to Embodiment 18 of the present invention. In addition, operation | movement of each part when circulating a non-azeotropic mixed refrigerant | coolant at the time of cooling operation, and a Mollier diagram at the time of cooling operation (FIG. 3)
The change in the composition of the surplus refrigerant is the same as that in the first embodiment, and thus the description thereof will be omitted.

As described above, the control circuit 21 inputs the temperature Ts of the gas refrigerant on the suction side of the compressor 1 at predetermined time intervals during the cooling operation, and checks whether or not hunting has occurred in the refrigeration cycle each time. Is monitored (S16
1) When hunting is detected, the aperture of the first aperture device 4a is increased through the aperture device drive circuit 22, and the aperture of the second aperture device 4b is increased (S16).
2, S163).

At this time, by opening the first aperture device 4a,
The degree of supercooling SC at the outlet of the outdoor heat exchanger 3 is reduced,
The refrigerant present in the outdoor heat exchanger 3 moves into the receiver 7 and the surplus refrigerant increases. At this time, the excess refrigerant in the receiver 7 moves to the accumulator 6 by opening the second expansion device 4b. For example, even under the condition where the extension pipes respectively connected to the outdoor heat exchanger 3 and the indoor heat exchanger 5 are long and the amount of surplus refrigerant stored in the receiver 7 is small, the flow reliably flows to the accumulator 6, The fluctuation of the refrigerant temperature in the accumulator 6 is suppressed.

As described above, according to the eighteenth embodiment, when hunting is detected, the first and second aperture devices 4a, 4a
By increasing the opening degree of b, the refrigerant present in the outdoor heat exchanger 3 is moved into the receiver 7, and the excess refrigerant in the receiver 7 is moved to the accumulator 6,
Since the fluctuation of the refrigerant temperature in the accumulator 6 is suppressed, there is an effect that hunting occurring in the refrigeration cycle can be suppressed.

In the present embodiment, the control for suppressing the hunting when the hunting is detected by the hunting determining means shown in the thirteenth embodiment has been described.
When hunting is detected by the hunting determining means according to any one of the fourth to sixteenth embodiments, the opening degree of each of the first and second expansion devices 4a and 4b may be increased to suppress the hunting. .

Embodiment 19 FIG. FIG. 36 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 19 of the present invention. The refrigeration cycle of FIG. 36 shows a state during the cooling operation, and the refrigeration cycle of the thirteenth embodiment described with reference to FIG.
The same or corresponding parts as those of the third embodiment described with reference to FIG.

In this embodiment, a bypass pipe 11 having a two-way valve 10 and a capillary tube 18 mounted between an accumulator 6 and a receiver 7, a two-way valve drive circuit 23, and a hunting determining means shown in the thirteenth embodiment And a control circuit 21 having a two-way valve control means for opening the two-way valve 10 when hunting is detected.

Next, the operation of the nineteenth embodiment will be described with reference to FIG. FIG. 37 is a flowchart showing control of the two-way valve according to the nineteenth embodiment of the present invention. The operation of each part when the non-azeotropic refrigerant mixture is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted. .

When the control circuit 21 detects the occurrence of hunting in the refrigeration cycle by the hunting determination means shown in Embodiment 13 during the cooling operation (S17).
1) Control is performed to open the two-way valve 10 through the two-way valve drive circuit 23 (S172). At this time, the high-pressure gas refrigerant in the receiver 7 flows to the accumulator 6 via the bypass pipe 11.

As described above, according to the nineteenth embodiment, when hunting is detected, the two-way valve 10 is opened and the receiver 7 is opened.
Since the gas refrigerant in the inside is returned to the accumulator 5 via the bypass pipe 11, the pressure fluctuation in the receiver 7 can be prevented, and therefore, the effect that the hunting generated in the refrigeration cycle can be suppressed can be suppressed. is there.

In this embodiment, when the hunting is detected by the hunting determining means shown in the thirteenth embodiment, the two-way valve 10 is opened to suppress it.
When hunting is detected by the hunting determination means according to any one of Embodiments 14 to 16, the two-way valve 10 may be opened to suppress the hunting.

Embodiment 20 FIG. This embodiment relates to control for suppressing hunting when it occurs in the refrigeration cycle, and will be described using, for example, hunting determination means shown in Embodiment 13 and hunting suppression control in Embodiment 17. The control circuit 21 of the present embodiment is configured such that, for example, the length L of the extension pipe between the outdoor heat exchanger 3 and the indoor heat exchanger 5 connected via the receiver 7 is input by a dip switch or the like. When the hunting is detected by the hunting determining means according to the thirteenth embodiment, the time for the refrigerant to make one cycle of the refrigeration cycle shown in FIG. 26, that is, the time constant T is calculated from the length L of the extension pipe. Then, the time constant T is compared with the time elapsed since the last time the hunting suppression control was performed, and when the elapsed time exceeds the time constant T, the hunting suppression control is started. When the first hunting is detected, the hunting suppression control is started.

Next, the operation of the twentieth embodiment will be described with reference to FIG. FIG. 38 is a flowchart showing hunting suppression control according to Embodiment 20 of the present invention. In addition,
The operation of each part when the non-azeotropic mixed refrigerant is circulated during the cooling operation, the Mollier diagram (FIG. 3) during the cooling operation, and the change in the composition of the surplus refrigerant are the same as those in the first embodiment, and therefore description thereof is omitted.

During the cooling operation, the control circuit 21 inputs the temperature Ts of the gas refrigerant on the suction side of the compressor 1 at predetermined time intervals, and monitors whether or not hunting has occurred in the refrigeration cycle each time. (S181), when the first hunting is detected, not shown, the hunting suppression control described below is started. When hunting is detected again thereafter, the length of the extension pipe input by the dip switch is used. A time constant T is obtained based on L (S18).
2, S183). Then, the elapsed time Tk since the last time the hunting suppression control was performed is compared with the time constant T (S
184, S185), when the elapsed time Tk exceeds the time constant T, the hunting suppression control is performed by increasing the opening of the second aperture device 4b through the aperture device drive circuit 22, as shown in FIG. 34 (S186). The elapsed time Tk is reset (S187). At this time, the surplus refrigerant stored in the receiver 7 moves to the accumulator 6 and suppresses a change in the refrigerant temperature in the accumulator 6. Then, monitoring for whether or not hunting has occurred in the refrigeration cycle is started again (S181).

As described above, according to the twentieth embodiment, when the hunting judging means detects that the refrigeration cycle is in a hunting state, the time constant T of the refrigeration cycle is calculated based on the length L of the extended pipe. Since the hunting suppression control is performed when the elapsed time after performing the hunting suppression control exceeds the time constant T, it is possible to prevent the hunting from being enlarged by the hunting suppression operation, and to ensure the hunting. There is an effect that it can be suppressed.

Although the present embodiment has been described using the hunting judging means shown in the thirteenth embodiment and the hunting suppression control shown in the seventeenth embodiment, the hunting judging means can be replaced by any one of the fourteenth to sixteenth embodiments. The hunting suppression control described in the eighteenth embodiment may be used in combination with any one of the thirteenth to sixteenth embodiments. Further, the present embodiment in which the hunting suppression control is performed when the elapsed time since the previous hunting suppression control was performed exceeds the time constant T may be applied to the nineteenth embodiment.

[0150]

As described above, according to the first aspect of the present invention, the receiver in which the accumulator is installed is provided with:
Since the surplus refrigerant generated when the refrigerant is circulated is stored, the surplus refrigerant does not accumulate in the accumulator, so that the change in the composition of the circulating refrigerant can be suppressed to a small value. There is an effect that fluctuations in pressure and capacity can be prevented.
Further, as described above, since the excess refrigerant does not accumulate in the accumulator, the refrigerant sucked into the compressor can be surely gasified, thereby improving the efficiency of the compressor and improving the COP of the refrigeration cycle. is there. Furthermore, since the refrigerant that has entered the receiver is cooled by the refrigerant inside the accumulator installed in the receiver, the enthalpy difference between the entrance and exit of the evaporator increases, and the pressure at the entrance of the evaporator increases. There is an effect that the COP of the refrigeration cycle is improved.

According to the second aspect of the present invention, the surplus refrigerant generated when the refrigerant is circulated is stored in the receiver provided in the accumulator, so that the surplus refrigerant is accumulated in the accumulator in the same manner as described above. The refrigerant does not accumulate, so that the change in the composition of the circulating refrigerant can be suppressed to a small value, and there is an effect that fluctuations in the operating pressure and capacity can be prevented. Further, as described above, since the excess refrigerant does not accumulate in the accumulator, the refrigerant sucked into the compressor can be surely gasified, thereby improving the efficiency of the compressor and improving the COP of the refrigeration cycle. is there. Furthermore, since the refrigerant entering the receiver is cooled by exchanging heat with the refrigerant inside the accumulator surrounding the receiver, the enthalpy difference between the inlet and the outlet of the evaporator increases, and the pressure at the inlet of the evaporator increases, As a result, there is an effect that the COP of the refrigeration cycle can be improved.

According to the third aspect of the present invention, the surplus refrigerant generated when the refrigerant is circulated is reliably stored in the receiver provided at the lower part or the upper part of the accumulator. It is possible to suppress the composition change to a small value, and to prevent fluctuations in operating pressure and performance, etc.
In addition, there is an effect that the efficiency of the compressor is improved and the COP of the refrigeration cycle is improved. In addition, since the refrigerant entering the receiver is cooled by the refrigerant inside the accumulator provided at the upper or lower part, the enthalpy difference between the entrance and exit of the evaporator increases, and the pressure at the entrance of the evaporator increases. There is an effect that the COP of the cycle can be improved. Furthermore, when the operation is stopped, the refrigerant that has returned to the accumulator by opening the two-way valve is taken into the receiver via the bypass pipe, so that when the operation is started, the refrigerant stored in the receiver is immediately evaporated. And the rising performance can be improved.

According to the fourth aspect of the present invention, the difference between the detected temperature of the first temperature sensor and the detected temperature of the second temperature sensor is calculated, and the calculated value is compared with the first reference temperature set in advance. And comparing the detected temperature of the fourth temperature sensor with the detected temperature of the third temperature sensor, and controlling the amount of throttle of the first throttle device based on the comparison result. Since the value is compared with a preset second reference value, and the throttle amount of the second throttle device is controlled based on the comparison result, the operating conditions such as the outside air temperature and the pipe length change. Even so, there is an effect that surplus refrigerant can be reliably stored in the receiver without being stored in the accumulator, and a change in the composition of the circulating refrigerant can be suppressed to a small value.

According to the fifth aspect of the present invention, the fourth temperature sensor is installed in the pipe between the compressor and the accumulator instead of the outlet of the evaporator, and the detected temperature and the third temperature are measured. And calculates a difference between the detected temperature of the temperature sensor and a third reference value that is set in advance, and controls the aperture amount of the second aperture device based on the comparison result. Therefore, also in the present invention, even if the operating conditions such as the outside air temperature and the pipe length change, the surplus refrigerant can be reliably stored in the receiver without accumulating in the accumulator, and the composition change of the circulating refrigerant can be suppressed to be small. There is an effect that can be.

According to the sixth aspect of the present invention, an inflow / outflow pipe is provided in a receiver in which an accumulator is installed, and
Since a plurality of holes are provided in the inflow and outflow pipes, it is possible to retain the refrigerant even if refrigerant from the indoor heat exchanger flows into the receiver. There is no need to provide a throttling device between the heat exchanger and the heat exchanger, so that an inexpensive refrigeration cycle can be provided.

According to the seventh aspect of the present invention, since the receiver provided with the inflow / outflow pipe is installed in the accumulator, even in the present invention, even if the refrigerant from the indoor heat exchanger flows into the receiver. The refrigerant can be retained, and therefore, there is no need to provide a throttling device between the receiver and the outdoor heat exchanger during the heating operation, so that an inexpensive refrigeration cycle can be provided.

According to the eighth aspect of the present invention, the opening degree of the second expansion device is reduced at the end of the defrost operation, and after a predetermined time has elapsed, the first expansion device is fully closed and the four-way valve is set to the heating mode. Since the switching is performed, the amount of the liquid refrigerant that returns to the accumulator when the operation is switched from the cooling operation to the heating operation can be reduced, and therefore, the volume of the accumulator can be reduced.

According to the ninth aspect of the present invention, when the operation is stopped,
The first and second throttle devices are fully closed, respectively.
Since the driving of the compressor is stopped, the excess refrigerant can be retained in the receiver, and therefore, the liquid refrigerant returning to the accumulator when the compressor is stopped can be reduced, and the volume of the accumulator can be reduced. Even if the size is reduced, it is possible to prevent the flow of the liquid refrigerant into the compressor, and it is possible to prevent the starting failure when the operation is started again. Further, when the operation is restarted, the liquid refrigerant held in the receiver can be promptly supplied to the indoor heat exchanger, so that there is an effect that the start-up performance of the operation is improved.

According to the tenth aspect of the present invention, at the start of the heating operation, the four-way valve is set to the cooling mode to start the compressor, and after a lapse of a predetermined time, the opening degree of the first expansion device is reduced. Since the valve was switched to heating mode,
At the start of the heating operation, a large amount of liquid refrigerant accumulated in the outdoor heat exchanger does not enter the accumulator,
Therefore, there is an effect that the volume of the accumulator can be reduced.

According to the eleventh aspect of the present invention, when the detected temperature of the fifth temperature sensor exceeds a third reference value set in advance, the second throttle device is fully opened, and the first throttle device is opened. The difference between the temperature detected by the temperature sensor and the temperature detected by the second temperature sensor is calculated, and the difference is compared with a first reference value set in advance. Since the aperture amount is controlled, there is an effect that a decrease in COP can be suppressed as much as possible.

According to the twelfth aspect of the present invention, when the pressure switch exceeds the fourth reference value set in advance, the first expansion device is fully opened, and the detected temperature of the sixth temperature sensor is set to And calculating a difference between the detected temperature of the third temperature sensor and a second reference value set in advance, and controlling the aperture amount of the second aperture device based on the comparison result. Therefore, there is an effect that a decrease in COP can be suppressed as much as possible.

According to the thirteenth aspect of the present invention, the fluctuation range of the detected temperature of the sixth temperature sensor is calculated every predetermined time, and when the fluctuation width exceeds a preset sixth reference value, the circulation is performed. Since the refrigeration cycle is recognized as causing hunting, it is possible to accurately monitor whether or not hunting has occurred in the refrigeration cycle.

According to the fourteenth aspect of the present invention, the fluctuation width of the difference between the detected temperature of the sixth temperature sensor and the detected temperature of the third temperature sensor is calculated at predetermined time intervals, and the fluctuation width is set in advance. Since it is determined that the circulating refrigerant is hunting when the refrigeration cycle exceeds the seventh reference value, the refrigeration cycle can be accurately monitored for hunting.

According to the fifteenth aspect of the present invention, the fluctuation range of the detected temperature of the fifth temperature sensor is calculated every predetermined time, and when the fluctuation width exceeds the preset eighth reference value, the circulation is performed. Since the refrigeration cycle is recognized as causing hunting, it is possible to accurately monitor whether or not hunting has occurred in the refrigeration cycle.

According to the sixteenth aspect of the present invention, the fluctuation range of the difference between the detected temperature of the fifth temperature sensor and the detected temperature of the first temperature sensor is calculated every predetermined time, and the fluctuation range is set in advance. When the circulating refrigerant exceeds the ninth reference value, it is recognized that the circulating refrigerant is hunting. Therefore, it is possible to accurately monitor whether the refrigeration cycle has hunting.

According to the seventeenth aspect of the present invention, when the hunting state is detected, the opening degree of the second expansion device is increased, so that hunting occurring in the refrigeration cycle can be suppressed. There is an effect that can be.

According to the eighteenth aspect of the present invention, when the hunting state is detected, the openings of the first and second expansion devices are increased, so that the hunting occurring in the refrigeration cycle is suppressed. There is an effect that can be.

According to the nineteenth aspect of the present invention, when the hunting state is detected, the two-way valve is opened.
Pressure fluctuation in the receiver can be prevented, and therefore, there is an effect that hunting generated in the refrigeration cycle can be suppressed.

According to the twentieth aspect of the present invention, the time constant of the circulation of the refrigerant is calculated in accordance with the length of the pipe between the condenser and the evaporator connected via the receiver, and the time constant of the refrigerant is calculated. Since the hunting is suppressed at a time interval or longer, there is an effect that the hunting is prevented from being enlarged by the hunting suppressing operation and the hunting can be suppressed reliably.

[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 perspective view showing a configuration of a unit of the air conditioner according to Embodiment 1.

FIG. 3 is a Mollier chart during a cooling operation.

FIG. 4 is a comparison diagram of a change in the composition of a circulating refrigerant when a non-azeotropic refrigerant mixture is stored in a receiver and an accumulator, respectively.

FIG. 5 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 2 of the present invention.

FIG. 6 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 3 of the present invention.

FIG. 7 is a block diagram of a refrigeration cycle showing another embodiment of the third embodiment.

FIG. 8 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 4 of the present invention.

FIG. 9 is a flowchart illustrating control of first and second aperture devices according to a fourth embodiment.

FIG. 10 is a block diagram illustrating a refrigeration cycle of, for example, an air conditioner according to Embodiment 6 of the present invention.

FIG. 11 is an enlarged explanatory view of a receiver provided in a refrigeration cycle according to a sixth embodiment.

FIG. 12 is a block diagram illustrating a refrigeration cycle of, for example, an air conditioner according to Embodiment 7 of the present invention.

FIG. 13 is an enlarged explanatory view of a receiver provided in a refrigeration cycle of a seventh embodiment.

FIG. 14 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 8 of the present invention.

FIG. 15 is a flowchart showing operations at the time of defrost operation and at the time of termination of the operation.

FIG. 16 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 9 of the present invention.

FIG. 17 is a flowchart illustrating control of first and second aperture devices according to a ninth embodiment.

FIG. 18 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 10 of the present invention.

FIG. 19 is a flowchart showing control of a four-way valve, first and second throttle devices in a tenth embodiment.

FIG. 20 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 11 of the present invention.

FIG. 21 is a flowchart illustrating control of first and second aperture devices according to an eleventh embodiment.

FIG. 22 illustrates a first diaphragm device and a second diaphragm device according to the eleventh embodiment.
FIG. 4 is a graph showing changes in the opening degree of the throttle device and discharge temperatures Td and COP of the compressor.

FIG. 23 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 12 of the present invention.

FIG. 24 is a flowchart illustrating control of first and second aperture devices according to a twelfth embodiment.

FIG. 25 illustrates a first diaphragm device and a second diaphragm device according to the twelfth embodiment.
FIG. 4 is a graph showing changes in the opening degree of the throttle device and discharge pressures Pd and COP of the compressor.

FIG. 26 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 13 of the present invention.

FIG. 27 is a flowchart showing hunting determination in a refrigeration cycle according to Embodiment 13.

FIG. 28 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 14 of the present invention.

FIG. 29 is a flowchart illustrating hunting determination in a refrigeration cycle according to a fourteenth embodiment.

FIG. 30 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 15 of the present invention.

FIG. 31 is a flowchart showing hunting determination in the refrigeration cycle of the fifteenth embodiment.

FIG. 32 is a block diagram illustrating a refrigeration cycle of, for example, an air conditioner according to Embodiment 16 of the present invention.

FIG. 33 is a flowchart showing hunting determination in the refrigeration cycle of the sixteenth embodiment.

FIG. 34 is a flowchart showing control of a second aperture device according to Embodiment 17 of the present invention.

FIG. 35 is a view showing the first and second embodiments according to the eighteenth embodiment of the present invention;
6 is a flowchart showing control of the aperture device of FIG.

FIG. 36 is a block diagram showing a refrigeration cycle of, for example, an air conditioner according to Embodiment 19 of the present invention.

FIG. 37 is a flowchart showing control of a two-way valve according to Embodiment 19 of the present invention.

FIG. 38 is a flowchart showing hunting suppression control according to Embodiment 20 of the present invention.

FIG. 39 is a block diagram showing a refrigeration cycle of a conventional air conditioner.

FIG. 40 is a block diagram of a conventional refrigeration cycle disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 46-14440.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 compressor, 2 four-way valve, 3 outdoor heat exchanger, 4a first expansion device, 4b second expansion device, 5 indoor heat exchanger, 6 accumulator, 7 receiver, 8 pressure vessel, 9 partition plate, 10 2 Side valve, 11 bypass pipe, 1
2 first temperature sensor, 13 second temperature sensor,
14 third temperature sensor, 15 fourth temperature sensor, 16 inflow / outflow pipe, 16a hole in outflow / inflow pipe, 18
Fifth temperature sensor, 19 capillary tube, 20 sixth temperature sensor, 21 control circuit, 22 diaphragm driving circuit, 2
3 Two-way valve drive circuit, 24 pressure switch, 25 Four-way valve drive circuit, 26 Compressor drive circuit.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Iijima, etc. 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (20)

[Claims] A compressor connected to the four-way valve via a pipe; a condenser connected to the four-way valve via a pipe; an evaporator connected to the four-way valve via a pipe; An accumulator connected to the four-way valve and the other to the compressor via a pipe, a receiver connected to the condenser via the pipe and the other to the evaporator via the pipe, and having the accumulator therein. A first throttle device provided in a tube between the receiver and the condenser; a second throttle device provided in a tube between the receiver and the evaporator;
A refrigeration cycle, comprising using a non-azeotropic mixed refrigerant composed of two or more refrigerants having different boiling points as refrigerant, and storing excess refrigerant generated during circulation in the receiver. 2. The refrigeration cycle according to claim 1, wherein the receiver is installed in the accumulator. 3. The refrigeration cycle according to claim 1, wherein the receiver is provided at one of an upper portion and a lower portion of the accumulator, and is connected to the accumulator via a bypass pipe having a two-way valve. . 4. A first temperature sensor installed on the condenser; a second temperature sensor installed on the outlet of the condenser; a third temperature sensor installed on the evaporator; A fourth temperature sensor installed at the outlet portion, a difference between a detected temperature of the first temperature sensor and a detected temperature of the second temperature sensor is calculated, and a value of the difference between the detected temperature and a predetermined first temperature sensor is calculated. And controls the amount of throttling of the first throttling device based on the comparison result. The difference between the temperature detected by the fourth temperature sensor and the temperature detected by the third temperature sensor is also determined. Is calculated, and its value is set to a second predetermined value.
4. A refrigeration system according to claim 1, further comprising a throttle device control means for comparing the reference value of the second throttle device with the reference value and controlling the throttle amount of the second throttle device based on the comparison result. cycle. 5. The fourth temperature sensor is installed in a pipe between a compressor and an accumulator instead of installing an outlet of an evaporator, and the expansion device control means controls the second expansion device. When controlling, a difference between the detected temperature of the fourth temperature sensor installed in the pipe between the compressor and the accumulator and the detected temperature of the third temperature sensor is calculated, and the value is set in advance to the value. 5. The refrigeration cycle according to claim 4, wherein the refrigeration cycle is compared with the third reference value, and the throttle amount of the second throttle device is controlled based on the comparison result. 6. A compressor connected to the four-way valve via a pipe, an outdoor heat exchanger connected to the four-way valve via a pipe, and an indoor heat exchanger connected to the four-way valve via a pipe. An accumulator, one connected to the four-way valve and the other connected to the compressor via a pipe, one connected to the outdoor heat exchanger and the other connected to the indoor heat exchanger via a pipe, respectively. A receiver having the accumulator therein; an outlet pipe having a plurality of holes erected between the receiver and the accumulator and connected to a pipe from the outdoor heat exchanger; and a receiver and the indoor heat exchange. A non-azeotropic mixed refrigerant comprising two or more types of refrigerant having different boiling points, and storing excess refrigerant generated during circulation in the receiver. Features cold Cycle. 7. The receiver provided with the inflow / outflow pipe,
The refrigeration cycle according to claim 6, wherein the refrigeration cycle is installed in an accumulator. 8. A compressor connected to the four-way valve via a pipe, an indoor heat exchanger connected to the four-way valve via a pipe, and an outdoor heat exchanger connected to the four-way valve via a pipe. An accumulator, one connected to the four-way valve and the other connected to the compressor via a pipe, one connected to the indoor heat exchanger, and the other connected to the outdoor heat exchanger via a pipe, respectively. A receiver having the accumulator on or above, a first throttle device provided on a pipe between the receiver and the outdoor heat exchanger, and a pipe between the receiver and the indoor heat exchanger. A second throttle device provided, at the end of the defrost operation, reduce the opening degree of the second throttle device, and after a lapse of a predetermined time, fully close the first throttle device to set the four-way valve to the heating mode. Liquid refrigerant control means for switching The refrigeration cycle, characterized in that using a non-azeotropic refrigerant composed of two or more kinds of refrigerants having different boiling points in the refrigerant. 9. The system according to claim 8, further comprising stop control means for completely closing the first and second throttle devices and stopping the operation of the compressor when the operation is stopped.
Refrigeration cycle as described. 10. When the heating operation is started, the four-way valve is set to the cooling mode to start the compressor, and after a lapse of a predetermined time, the opening degree of the first expansion device is reduced, and the four-way valve is set to the heating mode. 10. The refrigeration cycle according to claim 8, further comprising a heating start control unit that switches the heating cycle. 11. A first temperature sensor installed at the outdoor heat exchanger, a second temperature sensor installed at an outlet of the outdoor heat exchanger, and installed at a discharge pipe of the compressor. A fifth temperature sensor, when the detected temperature of the fifth temperature sensor exceeds a third reference value set in advance, fully opens the second throttle device, and detects the first temperature sensor. Calculating the difference between the temperature and the temperature detected by the second temperature sensor, comparing the calculated value with a first reference value set in advance, and based on the comparison result, the amount of aperture of the first aperture device; The refrigeration cycle according to any one of claims 8 to 10, further comprising a throttle device control means for controlling the pressure. 12. A third temperature sensor installed in the indoor heat exchanger, a sixth temperature sensor installed in a suction pipe of the compressor, and a pressure switch installed in a discharge pipe of the compressor. And when the pressure switch exceeds a preset fourth reference value, fully open the first throttle device, and
A difference between the detected temperature of the sixth temperature sensor and the detected temperature of the third temperature sensor is calculated, and the calculated value is compared with a second reference value set in advance. The refrigeration cycle according to any one of claims 8 to 11, further comprising a throttling device control means for controlling a throttling amount of the second throttling device. 13. A compressor connected to the four-way valve via a pipe, a condenser connected to the four-way valve via a pipe, and an evaporator connected to the four-way valve via a pipe. Is connected to the four-way valve, the other is connected to the compressor via a pipe, respectively, one is connected to the condenser, the other is connected to the evaporator via the pipe, respectively, the accumulator on the top or inside the A first throttle device provided in a tube between the receiver and the condenser; and a second throttle device provided in a tube between the receiver and the evaporator.
A throttling device, a sixth temperature sensor installed in the suction pipe of the compressor, and a fluctuation range of the detected temperature of the sixth temperature sensor calculated at predetermined time intervals. Hunting determination means for recognizing that the circulating refrigerant is hunting when the reference value exceeds 6. A non-azeotropic mixed refrigerant composed of two or more refrigerants having different boiling points is used as the refrigerant. A refrigeration cycle characterized by the following. 14. A sixth temperature sensor installed in a suction pipe of a compressor, and a third temperature sensor installed in the evaporator, wherein the hunting determination means is configured to perform the sixth hunting every predetermined time. The fluctuation range of the difference between the temperature detected by the temperature sensor and the temperature detected by the third temperature sensor is calculated, and when the fluctuation range exceeds a preset seventh reference value, the circulating refrigerant hunts. The refrigeration cycle according to claim 13, wherein the refrigeration cycle is recognized as being awake. 15. A fifth temperature sensor provided in a discharge pipe of a compressor, wherein the hunting determining means calculates a fluctuation range of a temperature detected by the fifth temperature sensor at predetermined time intervals, and calculates the fluctuation range. 14. The refrigeration cycle according to claim 13, wherein when the width exceeds a preset eighth reference value, it is recognized that the circulating refrigerant is hunting. 16. A fifth temperature sensor installed in a discharge pipe of a compressor, and a first temperature sensor installed in the condenser, wherein the hunting determination unit is configured to execute the fifth temperature sensor every predetermined time. The fluctuation range of the difference between the detected temperature of the temperature sensor and the detected temperature of the first temperature sensor is calculated, and when the fluctuation range exceeds a preset ninth reference value, the circulating refrigerant hunts. The refrigeration cycle according to claim 13, wherein the refrigeration cycle is recognized as being awake. 17. A throttle device control means for increasing an opening degree of said second throttle device when a hunting state is detected by said hunting determination means. The refrigeration cycle according to 1. 18. A throttling device control means for increasing the degree of opening of the first and second throttling devices when the hunting state is detected by the hunting judging means. The refrigeration cycle according to any one of the above. 19. A two-way valve control means for providing a bypass pipe having a two-way valve and a capillary tube between the accumulator and the receiver, and opening the two-way valve when the hunting state is detected by the hunting determination means. The refrigeration cycle according to any one of claims 13 to 16, further comprising: 20. A refrigerant circulation time constant is calculated according to a length of a pipe between a condenser and an evaporator connected via the receiver, and hunting is performed at a time interval equal to or longer than the time constant. The refrigeration cycle according to any one of claims 13 to 16, further comprising hunting suppression means for suppressing hunting.