Refrigeration cycle device

Abstract

The invention provides a refrigeration cycle device, and aims to suppress disproportionation reaction. A refrigeration cycle device in which a refrigerant is filled in a refrigerant circuit, the refrigerant including a refrigerant having a property of causing a disproportionation reaction, and in which a bypass pipe connecting a discharge-side pipe and a suction-side pipe of a compressor is provided is provided, the refrigeration cycle device being provided with: an electromagnetic valve in which an electromagnetic valve is provided to control the discharge-side pipe and the suction-side pipe of the compressor; a bypass pipe that controls the passage of the refrigerant flowing through the bypass pipe; and a control unit that controls the opening and closing of the solenoid valve on the basis of the discharge-side pressure of the compressor and the temperature of the compressor.

Description

Technical Field

[0001] The invention relates to a refrigeration cycle device. Background Art

[0002] In refrigeration, freezing, and commercial air conditioners, the mainstream R410A refrigerant has a global warming potential (GWP) of up to 2090. In order to prevent global warming, it is necessary to switch to a refrigerant with a lower GWP value. For example, R1234yf, R1132(E), and R1123 have been proposed as next-generation low-GWP candidate refrigerants.

[0003] When R1123 or R1132(E) is used as a component of a mixed refrigerant, if a disproportionation reaction (autolysis reaction) occurs, the pressure will rise with a large amount of heat release, so ensuring the reliability of the compressor and refrigeration cycle becomes a problem. It is known that when high energy is applied in an excessively high temperature and high pressure refrigerant atmosphere, the disproportionation reaction will start from this.

[0004] Patent document 1 discloses a system structure that suppresses the rotation speed of the compressor based on the disproportionation reaction pressure value of the refrigerant obtained from the exhaust gas temperature of the refrigerant discharged from the compressor and the outlet temperature of the condenser as a means for suppressing the disproportionation reaction. Patent document 2 discloses the following structure: by providing a pressure-fragile portion on a part of the outer contour of the compressor, the working fluid is released to the outside when the disproportionation reaction occurs, and the motor drive device of the motor that controls the compressor is destroyed by the fragile component, thereby stopping the compressor. Patent document 3 discloses the following structure: a high-low pressure bypass pipe is provided to connect the discharge side pipe of the compressor with the suction side pipe, and the bypass circuit is opened and closed by a fusible plug or a pressure valve.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6289611

[0008] Patent Document 2: Japanese Patent No. 6805794

[0009] Patent Document 3: Japanese Patent No. 6857815 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, in the technology of Patent Document 1, when the effect of reducing the pressure and temperature brought about by the speed suppression of the compressor is insufficient, there is a problem that the disproportionation reaction cannot be fully suppressed. For example, in the case of a scroll compressor, the refrigerant sucked in at the suction pressure is compressed to the discharge pressure based on the compression ratio set by the scroll tooth shape regardless of the speed, so it is considered that the discharge pressure will not decrease by simply reducing the speed. In addition, it is generally believed that if the refrigerant circulation volume is reduced due to the speed suppression, the heat dissipation effect of the refrigerant flowing in the closed container is weakened, and the temperature cannot be fully reduced.

[0012] In the technology described in Patent Document 2, the pressure-fragile part of the outer shell of the compressor is destroyed, and the high-temperature and high-pressure refrigerant is released to the outside, so there is a safety issue. In particular, in the case of products used in densely populated areas, shops, etc., there is a possibility of explosion sound with the destruction and smoke with the release of refrigerant. In addition, when the pressure-fragile part is destroyed, the product cannot be used and needs to be replaced, so the convenience is poor.

[0013] In the technology described in Patent Document 3, the disproportionation reaction occurs under excessively high temperature and high pressure. Therefore, when a fusible plug or a pressure valve is used for opening and closing, only one of the temperature or pressure can be sensed, and it is a physical sense. Therefore, there is a possibility of reaction delay, corrosion and other deterioration over the years.

[0014] The present invention has been made in view of such problems, and an object of the present invention is to suppress the disproportionation reaction.

[0015] Solutions to Solve Problems

[0016] The present invention is a refrigeration cycle device, in which a refrigerant is filled in a refrigerant circuit, wherein the refrigerant includes a refrigerant with the property of undergoing a disproportionation reaction, and a bypass pipe connecting the discharge side pipe of the compressor with the suction side pipe is provided in the refrigerant circuit. The refrigeration cycle device comprises: an electromagnetic valve, which controls the passage of the refrigerant flowing in the bypass pipe; and a control unit, which controls the opening and closing of the electromagnetic valve based on the discharge side pressure of the compressor and the compressor temperature.

[0017] Effects of the Invention

[0018] According to the present invention, the disproportionation reaction can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram showing a refrigeration cycle of an air conditioner.

[0020] Figure 2 is a cross-sectional view of the compressor.

[0021] Figure 3This is a flowchart showing the solenoid valve control process. This figure is an example figure.

[0022] In the figure:

[0023] 1—air conditioner; 1A—outdoor unit; 1B—indoor unit; 2—compressor; 3—oil separator; 4—four-way valve; 5—outdoor fan; 6—outdoor heat exchanger; 7—expansion valve; 8—liquid storage tank; 9—expansion valve; 10—indoor fan; 11—indoor heat exchanger; 13—suction side refrigerant piping; 14—discharge side refrigerant piping; 15—storage tank; 16—connecting refrigerant piping; 17—bypass piping; 18—solenoid valve; 21—pressure sensor; 22—temperature sensor; 23—control unit; 31—compression mechanism unit; 31a—fixed scroll; 31b—orbiting scroll; 32—motor unit; 32a—stator; 32b—rotor; 33—rotating shaft; 34—suction piping; 35—discharge piping; 36—return oil piping; 37—over-compression valve; 38—over-compression valve pressure plate. DETAILED DESCRIPTION

[0024] Figure 1 1 is a diagram showing a refrigeration cycle of an air conditioner 1. Here, the air conditioner 1 is an example of a refrigeration cycle device. As the refrigerant circulating in the refrigeration cycle, there are, for example, a mixed refrigerant in which R1132(E) is mixed in R1234yf, a mixed refrigerant in which R1123 is mixed in R1234yf, or a mixed refrigerant in which R1234yf is replaced with R1234ze. The air conditioner 1 of this embodiment uses such a mixed refrigerant and suppresses the disproportionation reaction. In addition, the refrigeration cycle device is not limited to the air conditioner 1, and may be, for example, a refrigerator.

[0025] The air conditioner 1 includes an outdoor unit 1A and an indoor unit 1B. The outdoor unit 1A includes a compressor 2, an oil separator 3, a four-way valve 4, an outdoor fan 5, an outdoor heat exchanger 6, an expansion valve 7 for heating, and a liquid storage tank 8. The compressor 2 compresses a low-temperature and low-pressure gas refrigerant and discharges it as a high-temperature and high-pressure gas refrigerant. A storage tank 15 is provided on the refrigerant piping 13 on the suction side of the compressor 2, and an oil separator 3 is provided on the refrigerant piping 14 on the discharge side of the compressor 2. The oil accumulated in the oil separator 3 returns to the compressor 2 via the oil return piping 12. A pressure sensor 21 is provided on the refrigerant piping 14 on the discharge side of the compressor 2 to detect the pressure in the piping, that is, the discharge side pressure of the compressor 2. In addition, a temperature sensor 22 is provided on the refrigerant piping 14 on the discharge side of the compressor 2 to detect the temperature of the compressor 2 (compressor temperature).

[0026] In the outdoor heat exchanger 6, heat exchange is performed between the refrigerant flowing in the heat transfer pipe and the outside air sent in from the outdoor fan 5. The outdoor heat exchanger 6 operates as a condenser or an evaporator by switching the four-way valve 4. The outdoor fan 5 is arranged near the outdoor heat exchanger 6 and sends outside air to the outdoor heat exchanger 6. The expansion valve 7 has a function of decompressing the refrigerant condensed in the "condenser" (one of the outdoor heat exchanger 6 and the indoor heat exchanger 11). In addition, the refrigerant decompressed in the expansion valve 7 is guided to the "evaporator" (the other of the outdoor heat exchanger 6 and the indoor heat exchanger 11).

[0027] The indoor unit 1B includes an expansion valve 9, an indoor fan 10, and an indoor heat exchanger 11. In the indoor heat exchanger 11, heat is exchanged between the refrigerant flowing through the heat transfer pipe and the indoor air sent from the indoor fan 10. The indoor heat exchanger 11 operates as a condenser or an evaporator by switching the four-way valve 4. The indoor fan 10 is provided near the indoor heat exchanger 11. The indoor fan 10 sends indoor air to the indoor heat exchanger 11. The parts of the outdoor unit 1A and the indoor unit 1B are connected by connecting the refrigerant pipe 16 to form a closed cycle refrigeration cycle.

[0028] Furthermore, in the present embodiment, a bypass pipe 17 is provided for connecting the suction-side refrigerant pipe 13 and the discharge-side refrigerant pipe 14 of the compressor 2, and a solenoid valve 18 is provided in the bypass pipe 17. More specifically, the bypass pipe 17 is provided between the four-way valve 4 and the storage tank 15 in the suction-side refrigerant pipe 13 and between the discharge-side refrigerant pipe 14. In addition, a control unit 23 for controlling the opening and closing of the solenoid valve 18 is provided in the outdoor unit 1A. The control unit 23 includes a CPU, a RAM, a ROM, etc., which are not shown in the figure, and controls the solenoid valve 18 by executing a program stored in the ROM, etc. In addition, as another example, the control unit 23 may also be composed of a circuit, etc.

[0029] When the air conditioner 1 is operated for cooling, the mixture of high-temperature, high-pressure gaseous refrigerant and oil discharged from the compressor 2 is separated into refrigerant and oil by the oil separator 3. The separated oil is directly returned to the oil storage part at the bottom of the compressor 2. The separated refrigerant condenses by dissipating heat to the outside air in the outdoor heat exchanger 6 through the four-way valve 4, and becomes a high-pressure liquid refrigerant. After passing through the liquid accumulator 8, the liquid refrigerant flows to the indoor unit 1B side through the connecting refrigerant pipe 16, and is decompressed by the expansion valve 9 for cooling to become a low-temperature and low-pressure gas-liquid two-phase state, and absorbs the heat of the indoor air in the indoor heat exchanger 11 and evaporates. The refrigerant evaporated in the indoor heat exchanger 11 returns to the outdoor unit 1A through the connecting refrigerant pipe 16, flows to the compressor 2 through the four-way valve 4, and is compressed again in the compressor 2.

[0030] Next, the case where the air conditioner 1 performs heating operation is described. In the case of heating operation, the refrigerant flow path is switched from the cooling operation through the four-way valve 4. In the case of heating operation, the mixture of high-temperature and high-pressure gaseous refrigerant and oil discharged from the compressor 2 is separated into refrigerant and oil by the oil separator 3. The separated oil is directly returned to the oil storage part at the bottom of the compressor 2. The separated refrigerant flows to the indoor unit 1B side through the four-way valve 4 and the connecting refrigerant pipe 16. The refrigerant entering the indoor unit 1B condenses by dissipating heat to the indoor air in the indoor heat exchanger 11 and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flows to the outdoor unit 1A side through the connecting refrigerant pipe 16. The high-pressure liquid refrigerant entering the outdoor unit 1A is decompressed by the expansion valve 7 for heating, becomes a low-temperature and low-pressure gas-liquid two-phase state, flows to the outdoor heat exchanger 6, and evaporates by absorbing the heat of the outdoor air to become a gaseous refrigerant. The refrigerant converted into a gas in the outdoor heat exchanger 6 flows into the compressor 2 through the four-way valve 4 and is compressed again in the compressor 2 .

[0031] Figure 2 3 is a longitudinal sectional view of the compressor 2. The compressor 2 of the present embodiment is a scroll compressor having an over-compression valve 37. The compressor 2 is a high-pressure chamber type compressor configured to discharge the exhaust gas compressed by the compression mechanism 31 into the sealed container 30 so that the pressure inside the sealed container 30 becomes substantially the discharge pressure.

[0032] exist Figure 2 In the compressor 2 shown, the compression mechanism 31 and the motor 32 are housed in a roughly cylindrical sealed container (high-pressure container) 30. The compression mechanism 31 includes a fixed scroll 31a and a rotating scroll 31b, and is disposed in the upper space of the sealed container 30. In addition, an over-compression valve 37 and an over-compression valve pressure plate 38 are provided on the upper portion of the compression mechanism 31, and in the case of excessive pressure rise, the pressure can be reduced by opening the over-compression valve 37. The motor 32 includes a stator 32a and a rotor 32b. The compressor 2 is structured such that the rotation of the motor 32 is transmitted to the compression mechanism 31 via a rotating shaft 33.

[0033] The compressor 2 further includes a suction pipe 34, a discharge pipe 35, and an oil return pipe 36, through which fluid can enter and exit the outside. The suction pipe 34 is an inlet for the refrigerant to flow into the sealed container 30, and is connected to the suction pipe 34. Figure 1 The discharge pipe 35 is connected to the suction side refrigerant pipe 13 shown in the figure. The discharge pipe 35 is an outlet for discharging a mixture of refrigerant and a small amount of oil. Figure 1 The oil return pipe 36 is connected to the discharge side refrigerant pipe 14 shown. The oil return pipe 36 is an inlet for returning the oil separated from the mixture to the inside of the closed container 30. Figure 1 The oil return pipe 12 is shown connected.

[0034] When the motor 32 is operated, its rotation is transmitted to the compression mechanism 31 via the rotating shaft 33, causing the orbiting scroll 31b to orbit. As the orbiting scroll 31b and the fixed scroll 31c move relative to each other, the refrigerant is sucked into the compression mechanism 31 from the suction pipe 34 and compressed.

[0035] Next, the control of the electromagnetic valve 18 is described. The circuit including the bypass pipe 17 is used to reduce the startup load of the air conditioner 1. In the bypass circuit connecting the discharge side refrigerant pipe 14 and the suction side refrigerant pipe 13 of the compressor 2, by opening the electromagnetic valve 18, the pressure inside the compressor 2 is balanced with the low-pressure side, and the temperature of the discharge side refrigerant is reduced by mixing the high-temperature discharge side refrigerant and the low-temperature suction side refrigerant. Thus, the pressure and temperature can be reduced by opening and closing the electromagnetic valve 18 for about 30 seconds.

[0036] In the air conditioner 1 of the present embodiment, the bypass circuit including the bypass pipe 17 is used to suppress the disproportionation reaction. Specifically, the control unit 23 performs Figure 3 The solenoid valve control process is shown. Figure 3 1 is a flowchart showing the solenoid valve control process. First, in step S100 , the control unit 23 obtains the discharge side pressure from the pressure sensor 21 . Next, in step S102 , the control unit 23 obtains the compressor temperature from the temperature sensor 22 .

[0037] Next, in step S104, the control unit 23 compares the obtained discharge side pressure with a pre-set first pressure threshold, and compares the obtained compressor temperature with a pre-set first temperature threshold. Then, the control unit 23 confirms whether the discharge side pressure and the compressor temperature meet the first condition. Here, the first condition is that the obtained discharge side pressure is higher than the first pressure threshold, and the obtained compressor temperature is higher than the first temperature threshold. When the first condition is met (step S104: yes), the control unit 23 opens the solenoid valve 18 (step S106). Here, the first pressure threshold and the first temperature threshold are respectively the pressure and temperature at which the disproportionation reaction occurs. The first pressure threshold is preferably, for example, 4.3MPaG. The first temperature threshold is preferably, for example, 130°C. In this way, since the first pressure threshold and the first temperature threshold are set, the solenoid valve 18 can be opened before the disproportionation reaction occurs.

[0038] When the first condition is not satisfied, that is, when the acquired discharge side pressure is less than the first pressure threshold value or the acquired compressor temperature is less than the first temperature threshold value (step S104: No), the control unit 23 causes the process to proceed to step S100. In this case, the control unit 23 periodically repeats the processes of steps S100 to S104 until the discharge side pressure and the compressor temperature satisfy the first condition. In this way, by opening the solenoid valve 18 when the first condition is satisfied, the disproportionation reaction can be suppressed.

[0039] After the processing of step S106, the control unit 23 obtains the discharge side pressure from the pressure sensor 21 again in step S108. Then, in step S110, the control unit 23 obtains the compressor temperature from the temperature sensor 22. Then, in step S112, the control unit 23 compares the obtained discharge side pressure with a preset second pressure threshold, and compares the obtained compressor temperature with a preset second temperature threshold. Here, the second pressure threshold is set to a value equal to the first pressure threshold. In addition, the second temperature threshold is set to a value equal to the first temperature threshold.

[0040] Then, the control unit 23 confirms whether the discharge side pressure and temperature meet the second condition. Here, the second condition is that the obtained discharge side pressure is lower than the second pressure threshold and the obtained compressor temperature is lower than the second temperature threshold. When the second condition is met (step S112: yes), the control unit 23 closes the solenoid valve 18 (step S114). Thereafter, the control unit 23 causes the processing to enter step S100, and periodically repeats the processing of steps S100 to S104 until the discharge side pressure and the compressor temperature meet the first condition. In this way, when the second condition is met, by closing the solenoid valve 18, the discharge side pressure and the temperature of the compressor 2 can be prevented from dropping excessively.

[0041] On the other hand, when the second condition is not satisfied, that is, when the acquired discharge side pressure is equal to or higher than the second pressure threshold value or the acquired compressor temperature is equal to or higher than the second temperature threshold value (step S112: No), the control unit 23 advances the process to step S108. In this case, the control unit 23 periodically repeats the processes of steps S108 to S112 until the discharge side pressure and the compressor temperature satisfy the second condition.

[0042] As described above, the air conditioner 1 of the present embodiment performs a process for preventing the disproportionation reaction based not only on the discharge side pressure of the compressor 2 or the temperature of the compressor 2, but also on both. The disproportionation reaction occurs in an excessively high temperature and high pressure refrigerant atmosphere. Therefore, in order to suppress the disproportionation reaction, it is necessary to quickly reduce the high temperature and high pressure. Therefore, in the present embodiment, when the compressor temperature and pressure become above the threshold value, the discharge side pressure and the compressor temperature are reduced by opening the solenoid valve 18 of the circuit including the bypass pipe 17. In this way, the disproportionation reaction can be prevented from occurring.

[0043] The present invention is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims, for example, by applying a modification of a certain embodiment to other embodiments.

[0044] As such a first modification, the second pressure threshold referred to in the solenoid valve control process may be lower than the first pressure threshold, and the second temperature threshold may be set to a value lower than the first temperature threshold. This can prevent the solenoid valve 18 from being opened and closed frequently.

[0045] In addition, as a second modification, the surface temperature of the compressor 2 may be acquired as the compressor temperature. Here, the surface temperature of the compressor 2 is detected by a temperature sensor provided on the surface of the compressor 2.

[0046] In addition, as a third modified example, the control unit 23 only needs to control the electromagnetic valve 18 based on the discharge side pressure of the compressor 2 and the compressor temperature, and the specific control method is not limited to the embodiment. For example, the control unit 23 can further adjust the opening of the electromagnetic valve 18 in a manner such that the higher the discharge side pressure and the compressor temperature, the larger the opening of the electromagnetic valve 18.

Claims

1. A refrigeration cycle device, wherein a refrigerant circuit is filled with a refrigerant, The refrigeration cycle device is characterized in that The refrigerant includes a refrigerant having a property of undergoing a disproportionation reaction, and a bypass pipe is provided in the refrigerant circuit to connect a discharge-side pipe of the compressor with a suction-side pipe. The refrigeration cycle device comprises: a solenoid valve that controls passage of the refrigerant flowing in the bypass pipe; and A control unit controls opening and closing of the electromagnetic valve based on a discharge-side pressure of the compressor and a compressor temperature.

2. The refrigeration cycle device according to claim 1, characterized in that: The control unit opens the solenoid valve when the discharge-side pressure is equal to or higher than a first pressure threshold and the compressor temperature is equal to or higher than a first temperature threshold.

3. The refrigeration cycle device according to claim 2, characterized in that: The control unit closes the solenoid valve when the discharge-side pressure is lower than a second pressure threshold and the compressor temperature is lower than a second temperature threshold.

4. The refrigeration cycle device according to claim 1, characterized in that: The refrigerant having the property of causing the disproportionation reaction is a mixed refrigerant containing R1132(E) or R1123.

5. The refrigeration cycle device according to claim 1, characterized in that: The compressor is a scroll compressor with an over-compression valve.

6. The refrigeration cycle device according to claim 1, characterized in that: The compressor temperature is acquired by a temperature sensor provided in the discharge-side pipe of the compressor.

7. The refrigeration cycle device according to claim 1, characterized in that: The compressor temperature is acquired by a temperature sensor provided on a surface of the compressor.

8. The refrigeration cycle device according to claim 1, characterized in that: The compressor is a high-pressure chamber type in which the exhaust gas compressed by the compression mechanism is discharged into a closed container of the compressor and the pressure inside the closed container becomes substantially the exhaust pressure.

Images