WO2015136979A1

WO2015136979A1 - Refrigeration cycle device

Info

Publication number: WO2015136979A1
Application number: PCT/JP2015/051125
Authority: WO
Inventors: 英明前山; 佐藤　幸一
Original assignee: 三菱電機株式会社; 旭硝子株式会社
Priority date: 2014-03-14
Filing date: 2015-01-16
Publication date: 2015-09-17
Also published as: KR101841869B1; JPWO2015136979A1; JP6815351B2; CN106104174A; JP2018112396A; CZ2016565A3; JP2020073649A; JP6453849B2; KR20160133517A; CN106104174B

Abstract

A compressor (12), a four-way valve (13), an outdoor heat exchanger (14), an expansion valve (15), and an indoor heat exchanger (16) are connected in a refrigerant circuit (11a) in which a refrigerant containing HFO-1123 circulates. This refrigeration cycle device (10) controls the pressure of the refrigerant in a flow path (that is, the high-pressure side) from the compressor (12) to the expansion valve (15) in the refrigerant circuit (11a) by means of a control mechanism so as to be equal to or less than a threshold value. Thus, even if a disproportionation reaction of the HFO-1123 occurs in a portion of the circuit, such as the compressor (12), proliferation of the reaction is prevented.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus.

In recent years, reduction of greenhouse gases has been demanded from the viewpoint of preventing global warming. A refrigerant having a lower global warming potential (GWP) is also being studied for refrigerants used in refrigeration cycle apparatuses such as air conditioners. Currently, the G410 of R410A widely used for air conditioners is 2088, which is a very large value. The GWP of difluoromethane (R32), which has begun to be introduced in recent years, is also a considerably large value of 675.

As a refrigerant having a low GWP, carbon dioxide (R744: GWP = 1), ammonia (R717: GWP = 0), propane (R290: GWP = 6), 2,3,3,3-tetrafluoropropene (R1234yf: GWP) = 4), 1,3,3,3-tetrafluoropropene (R1234ze: GWP = 6) and the like.

Since these low GWP refrigerants have the following problems, it is difficult to apply them to general air conditioners.
R744: Since the operating pressure is very high, there is a problem of ensuring a withstand pressure. Moreover, since critical temperature is as low as 31 degreeC, ensuring the performance in an air conditioner use becomes a subject.
-R717: Since it is highly toxic, there is a problem of ensuring safety.
-R290: Since it is highly flammable, there is a problem of ensuring safety.
R1234yf / R1234ze: Since the volume flow rate becomes large at a low operating pressure, there is a problem of performance degradation due to an increase in pressure loss.

As a refrigerant for solving the above problems, there is 1,1,2-trifluoroethylene (HFO-1123) (see, for example, Patent Document 1). This refrigerant has the following advantages in particular.
-Since the operating pressure is high and the volume flow rate of the refrigerant is small, the pressure loss is small and it is easy to ensure performance.
-GWP is less than 1 and is highly advantageous as a measure against global warming.

International Publication No. 2012/157774

HFO-1123 has the following problems.
(1) When ignition energy is applied in a high temperature and high pressure state, an explosion occurs (for example, see Non-Patent Document 1).
(2) The atmospheric life is very short, less than 2 days. There is concern about a decrease in chemical stability of the refrigeration cycle system.

To apply HFO-1123 to a refrigeration cycle apparatus, it is necessary to solve the above problems.

As for the problem (1), it became clear that explosion occurred due to the chain of disproportionation reaction. The conditions under which this phenomenon occurs are the following two points.
(1a) Ignition energy (high temperature part) is generated inside the refrigeration cycle apparatus (particularly the compressor), and a disproportionation reaction occurs.
(1b) The disproportionation reaction is chained and diffused at high temperature and high pressure.

(2) For the problem (2), it is necessary to ensure the chemical stability of the refrigeration cycle system.

An object of the present invention is to prevent explosion due to a disproportionation reaction of HFO-1123 in a compressor, for example. An object of the present invention is to avoid the establishment of the condition (1b).

A refrigeration cycle apparatus according to an aspect of the present invention includes:
A refrigerant circuit in which a compressor, a first heat exchanger, an expansion mechanism, and a second heat exchanger are connected, and a refrigerant containing 1,1,2-trifluoroethylene circulates;
A control mechanism for controlling the pressure of the refrigerant in the flow path from the compressor to the expansion mechanism of the refrigerant circuit to be equal to or less than a threshold value.

In the present invention, a refrigerant containing 1,1,2-trifluoroethylene is applied to the refrigeration cycle apparatus. The control mechanism of the refrigeration cycle apparatus controls the pressure of the refrigerant in the flow path from the compressor of the refrigerant circuit to the expansion mechanism to a threshold value or less. Thereby, in the refrigeration cycle apparatus, the disproportionation reaction of HFO-1123 is prevented from diffusing as a chain reaction, and an explosion due to the disproportionation reaction can be prevented.

FIG. 3 is a circuit diagram of the refrigeration cycle apparatus (during cooling) according to Embodiment 1. FIG. 3 is a circuit diagram of the refrigeration cycle apparatus (when heating) according to Embodiment 1. 1 is a longitudinal sectional view of a compressor according to Embodiment 1. FIG. The longitudinal cross-section partial enlarged view of the compressor which concerns on Embodiment 1, and the top view of the bypass valve with which the compressor which concerns on Embodiment 1 is provided. FIG. 3 is an electrical connection diagram of the stator of the electric element and the pressure fuse provided in the compressor according to the first embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
1 and 2 are circuit diagrams of a refrigeration cycle apparatus 10 according to the present embodiment. FIG. 1 shows the refrigerant circuit 11a during cooling. FIG. 2 shows the refrigerant circuit 11b during heating.

In the present embodiment, the refrigeration cycle apparatus 10 is an air conditioner. Note that this embodiment can be applied even if the refrigeration cycle apparatus 10 is a device other than an air conditioner (for example, a heat pump cycle apparatus).

1 and 2, the refrigeration cycle apparatus 10 includes

refrigerant circuits

11a and 11b through which refrigerant circulates.

A compressor 12, a four-way valve 13, an outdoor heat exchanger 14, an expansion valve 15, and an indoor heat exchanger 16 are connected to the

refrigerant circuits

11a and 11b. The compressor 12 compresses the refrigerant. The four-way valve 13 switches the direction of refrigerant flow between cooling and heating. The outdoor heat exchanger 14 is an example of a first heat exchanger. The outdoor heat exchanger 14 operates as a condenser during cooling, and dissipates the refrigerant compressed by the compressor 12. The outdoor heat exchanger 14 operates as an evaporator during heating, and heats the refrigerant by exchanging heat between the outdoor air and the refrigerant expanded by the expansion valve 15. The expansion valve 15 is an example of an expansion mechanism. The expansion valve 15 expands the refrigerant radiated by the condenser. The indoor heat exchanger 16 is an example of a second heat exchanger. The indoor heat exchanger 16 operates as a condenser during heating, and dissipates the refrigerant compressed by the compressor 12. The indoor heat exchanger 16 operates as an evaporator during cooling, and heats the refrigerant by exchanging heat between the indoor air and the refrigerant expanded by the expansion valve 15.

The refrigeration cycle apparatus 10 further includes a control device 17.

The control device 17 is, for example, a microcomputer. Although only the connection between the control device 17 and the compressor 12 is shown in the figure, the control device 17 is connected not only to the compressor 12 but also to each element connected to the

refrigerant circuits

11a and 11b. The control device 17 monitors and controls the state of each element.

The refrigeration cycle apparatus 10 further includes a pressure sensor 91 and a pressure switch 92. The pressure sensor 91 and the pressure switch 92 will be described later.

Further, a bypass valve 93 is connected to the

refrigerant circuits

11a and 11b. The bypass valve 93 will also be described later.

In the present embodiment, a refrigerant containing 1,1,2-trifluoroethylene (HFO-1123) is used as the refrigerant circulating in the

refrigerant circuits

11a and 11b. This refrigerant may be HFO-1123 alone or a mixture containing 1% or more of HFO-1123. That is, if the refrigerant used in the refrigeration cycle apparatus 10 contains 1 to 100% of HFO-1123, the present embodiment can be applied and the effects described later can be obtained.

As a suitable refrigerant, a mixture of HFO-1123 and difluoromethane (R32) can be used. For example, a mixture containing 40 wt% HFO-1123 and 60 wt% R32 can be used. Either one or both of HFO-1123 and R32 in this mixture may be replaced with another substance. HFO-1123 may be replaced with a mixture of HFO-1123 and another ethylene-based fluorohydrocarbon. Other ethylene fluorocarbons include fluoroethylene (HFO-1141), 1,1-difluoroethylene (HFO-1132a), trans-1,2-difluoroethylene (HFO-1132 (E)), cis- 1,2-difluoroethylene (HFO-1132 (Z)) can be used. R32 is 2,3,3,3-tetrafluoropropene (R1234yf), trans-1,3,3,3-tetrafluoropropene (R1234ze (E)), cis-1,3,3,3-tetrafluoro. Propene (R1234ze (Z)), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1,2,2-pentafluoroethane (R125) may be substituted. Alternatively, R32 may be replaced with a mixture of any two or more of R32, R1234yf, R1234ze (E), R1234ze (Z), R134a, and R125.

When using any refrigerant, it is necessary to consider the above-mentioned problem (1). In particular, it is necessary to avoid the establishment of the condition (1b) described above. That is, in the refrigeration cycle apparatus 10, it is necessary to avoid the disproportionation reaction from being chained and diffused.

The refrigeration cycle apparatus 10 controls the refrigerant pressure in the flow path (that is, the high pressure side) from the compressor 12 to the expansion valve 15 of the

refrigerant circuits

11a and 11b to be equal to or less than the threshold value by the control mechanism. Thereby, diffusion of the disproportionation reaction can be prevented.

FIG. 3 is a longitudinal sectional view of the compressor 12. In this figure, hatching representing a cross section is omitted.

In the present embodiment, the compressor 12 is a one-cylinder rotary compressor. Even if the compressor 12 is a multi-cylinder rotary compressor or a scroll compressor, if the inside of the container is in a discharge pressure atmosphere (that is, a high pressure level comparable to the refrigerant discharge pressure), this Embodiments can be applied.

3, the compressor 12 includes a sealed container 20, a compression element 30, an electric element 40, and a shaft 50.

The sealed container 20 is an example of a container. A suction pipe 21 for sucking the refrigerant and a discharge pipe 22 for discharging the refrigerant are attached to the sealed container 20.

The compression element 30 is stored in the sealed container 20. Specifically, the compression element 30 is installed in the lower part inside the sealed container 20. The compression element 30 compresses the refrigerant sucked into the suction pipe 21.

The electric element 40 is also accommodated in the sealed container 20. Specifically, the electric element 40 is installed at a position in the sealed container 20 where the refrigerant compressed by the compression element 30 passes before being discharged from the discharge pipe 22. That is, the electric element 40 is installed above the compression element 30 inside the sealed container 20. The electric element 40 drives the compression element 30. The electric element 40 is a concentrated winding motor.

Refrigerator oil that lubricates the sliding portion of the compression element 30 is stored at the bottom of the sealed container 20. As the refrigerating machine oil, for example, POE (polyol ester), PVE (polyvinyl ether), and AB (alkylbenzene) are used.

The compressor 12 further includes a bypass valve 94, a pressure fuse 95, and a relief valve 96. These will be described later. A spring 97 is attached to the bypass valve 94.

Hereinafter, details of the compression element 30 will be described.

The compression element 30 includes a cylinder 31, a rolling piston 32, a vane (not shown), a main bearing 33, and a sub bearing 34.

The outer periphery of the cylinder 31 is substantially circular in plan view. A cylinder chamber that is a substantially circular space in plan view is formed inside the cylinder 31. The cylinder 31 is open at both axial ends.

The cylinder 31 is provided with a vane groove (not shown) that communicates with the cylinder chamber and extends in the radial direction. A back pressure chamber, which is a substantially circular space in plan view, communicating with the vane groove is formed outside the vane groove.

The cylinder 31 is provided with a suction port (not shown) through which gas refrigerant is sucked from the

refrigerant circuits

11a and 11b. The suction port penetrates from the outer peripheral surface of the cylinder 31 to the cylinder chamber.

The cylinder 31 is provided with a discharge port (not shown) through which the compressed refrigerant is discharged from the cylinder chamber. The discharge port is formed by cutting out the upper end surface of the cylinder 31.

The rolling piston 32 has a ring shape. The rolling piston 32 moves eccentrically in the cylinder chamber. The rolling piston 32 is slidably fitted to the eccentric shaft portion 51 of the shaft 50.

The shape of the vane is a flat, substantially rectangular parallelepiped. The vane is installed in the vane groove of the cylinder 31. The vane is always pressed against the rolling piston 32 by a vane spring provided in the back pressure chamber. Since the inside of the sealed container 20 is at a high pressure, when the operation of the compressor 12 starts, the force due to the difference between the pressure in the sealed container 20 and the pressure in the cylinder chamber is applied to the back surface of the vane (that is, the surface on the back pressure chamber side). Works. For this reason, the vane spring is mainly used for the purpose of pressing the vane against the rolling piston 32 when the compressor 12 is started (when there is no difference in pressure between the sealed container 20 and the cylinder chamber).

The main bearing 33 has a substantially inverted T shape when viewed from the side. The main bearing 33 is slidably fitted to a main shaft portion 52 that is a portion above the eccentric shaft portion 51 of the shaft 50. The main bearing 33 closes the cylinder chamber of the cylinder 31 and the upper side of the vane groove.

The auxiliary bearing 34 is substantially T-shaped when viewed from the side. The auxiliary bearing 34 is slidably fitted to the auxiliary shaft portion 53 that is a portion below the eccentric shaft portion 51 of the shaft 50. The auxiliary bearing 34 closes the cylinder chamber of the cylinder 31 and the lower side of the vane groove.

The main bearing 33 includes a discharge valve (not shown). A discharge muffler 35 is attached to the outside of the main bearing 33. The high-temperature and high-pressure gas refrigerant discharged through the discharge valve once enters the discharge muffler 35 and is then discharged from the discharge muffler 35 into the space in the sealed container 20. The discharge valve and the discharge muffler 35 may be provided in the auxiliary bearing 34 or both the main bearing 33 and the auxiliary bearing 34.

The material of the cylinder 31, the main bearing 33, and the auxiliary bearing 34 is gray cast iron, sintered steel, carbon steel, or the like. The material of the rolling piston 32 is, for example, alloy steel containing chromium or the like. The material of the vane is, for example, high speed tool steel.

A suction muffler 23 is provided beside the sealed container 20. The suction muffler 23 sucks low-pressure gas refrigerant from the

refrigerant circuits

11a and 11b. The suction muffler 23 prevents the liquid refrigerant from directly entering the cylinder chamber of the cylinder 31 when the liquid refrigerant returns. The suction muffler 23 is connected to the suction port of the cylinder 31 via the suction pipe 21. The main body of the suction muffler 23 is fixed to the side surface of the sealed container 20 by welding or the like.

Hereinafter, details of the electric element 40 will be described.

In the present embodiment, the electric element 40 is a brushless DC (Direct Current) motor. The present embodiment can be applied even if the electric element 40 is a motor (for example, an induction motor) other than the brushless DC motor.

The electric element 40 includes a stator 41 and a rotor 42.

The stator 41 is fixed in contact with the inner peripheral surface of the sealed container 20. The rotor 42 is installed inside the stator 41 with a gap of about 0.3 to 1 mm.

The stator 41 includes a stator core 43 and a stator winding 44. The stator core 43 is manufactured by punching a plurality of electromagnetic steel sheets having a thickness of 0.1 to 1.5 mm into a predetermined shape, laminating them in the axial direction, and fixing them by caulking or welding. The stator winding 44 is wound around the stator core 43 in a concentrated manner via an insulating member 48. The material of the insulating member 48 is, for example, PET (polyethylene terephthalate), PBT (polybutylene terephthalate), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer). PTFE (polytetrafluoroethylene), LCP (liquid crystal polymer), PPS (polyphenylene sulfide), and phenol resin. A lead wire 45 is connected to the stator winding 44.

A plurality of notches are formed on the outer periphery of the stator core 43 at substantially equal intervals in the circumferential direction. Each notch becomes one of the passages of the gas refrigerant discharged from the discharge muffler 35 to the space in the sealed container 20. Each notch also serves as a passage for refrigerating machine oil returning from the top of the electric element 40 to the bottom of the sealed container 20.

The rotor 42 includes a rotor core 46 and a permanent magnet (not shown). As with the stator core 43, the rotor core 46 is formed by punching a plurality of electromagnetic steel sheets having a thickness of 0.1 to 1.5 mm into a predetermined shape, stacking them in the axial direction, and fixing them by caulking or welding. Produced. The permanent magnet is inserted into a plurality of insertion holes formed in the rotor core 46. For example, a ferrite magnet or a rare earth magnet is used as the permanent magnet.

The rotor core 46 is formed with a plurality of through holes penetrating substantially in the axial direction. Each through hole becomes one of the passages of the gas refrigerant discharged from the discharge muffler 35 to the space in the sealed container 20, similarly to the cutout of the stator core 43.

A power terminal 24 (for example, a glass terminal) connected to an external power source is attached to the top of the sealed container 20. The power terminal 24 is fixed to the sealed container 20 by welding, for example. A lead wire 45 from the electric element 40 is connected to the power terminal 24.

At the top of the sealed container 20, a discharge pipe 22 having both axial ends opened is attached. The gas refrigerant discharged from the compression element 30 is discharged from the space in the sealed container 20 through the discharge pipe 22 to the external

refrigerant circuits

11a and 11b.

Hereinafter, the operation of the compressor 12 will be described.

Electric power is supplied from the power supply terminal 24 to the stator 41 of the electric element 40 via the lead wire 45. Thereby, the rotor 42 of the electric element 40 rotates. The rotation of the rotor 42 causes the shaft 50 fixed to the rotor 42 to rotate. As the shaft 50 rotates, the rolling piston 32 of the compression element 30 rotates eccentrically in the cylinder chamber of the cylinder 31 of the compression element 30. The space between the cylinder 31 and the rolling piston 32 is divided into two by the vanes of the compression element 30. As the shaft 50 rotates, the volume of these two spaces changes. In one space, the refrigerant is sucked from the suction muffler 23 by gradually increasing the volume. In the other space, the volume of the gas refrigerant is gradually reduced to compress the gas refrigerant therein. The compressed gas refrigerant is discharged once from the discharge muffler 35 to the space in the sealed container 20. The discharged gas refrigerant passes through the electric element 40 and is discharged out of the sealed container 20 from the discharge pipe 22 at the top of the sealed container 20.

Hereinafter, an implementation example of the control mechanism according to the present embodiment will be described. Only one of the implementation examples may be applied, or some or all may be applied in combination.

As described above, the control mechanism controls the pressure of the refrigerant on the high pressure side of the

refrigerant circuits

11a and 11b to be equal to or lower than the threshold value.

In the refrigerant containing HFO-1123, the higher the pressure, the easier the disproportionation chain reaction. In the present embodiment, by controlling so that the high-pressure side does not become a pressure higher than a certain level, even if a disproportionation reaction occurs in some parts such as the compressor 12, the diffusion can be prevented.

In the implementation example described below, one threshold value is set for each. When two or more implementation examples are combined, two or more threshold values are set. In that case, it is possible to prevent the disproportionation reaction from being diffused in multiple stages by applying the thresholds in order starting from a looser threshold.

First, a first example in which the first value is set as the threshold will be described.

In the first example, the control device 17 and the pressure sensor 91 shown in FIGS. 1 and 2 function as main elements of the control mechanism. When the pressure of the refrigerant on the high pressure side of the

refrigerant circuits

11a and 11b reaches the first value, the control device 17 decreases the rotational speed of the electric element 40 of the compressor 12. For example, the first value is set to 4 to 5 MPa.

The control device 17 may predict that the pressure exceeds the first value from the tendency of the pressure change, and may perform the deceleration control of the electric element 40 before the pressure exceeds the first value. The control device 17 may perform stop control of the electric element 40 instead of deceleration control when it is determined that the pressure change is abrupt and there is clearly an abnormality such as circuit blockage.

The pressure on the high-pressure side can be accurately detected by the pressure sensor 91 installed in the high-pressure piping of the

refrigerant circuits

11a and 11b. Instead of using the pressure sensor 91, a method of measuring the temperature of the heat exchanger or the compressor 12 and estimating the pressure on the high pressure side from the temperature may be used.

In the first example, it is not necessary to stop the operation of the compressor 12. Therefore, the pressure conditions during operation of the compressor 12 do not change significantly. Therefore, the operation can be continued without impairing the operation state of the refrigeration cycle apparatus 10. Further, since the control device 17 can recognize that the protection operation has been performed, it is possible to control the state of the compressor 12 or other elements so that the pressure does not exceed the first value again.

Next, a second example in which the second value is set as the threshold will be described.

FIG. 4 is a partially enlarged view of the longitudinal section of the compressor 12 and a plan view of the bypass valve 94 provided in the compressor 12.

In the second example, the bypass valve 93 shown in FIGS. 1 and 2 or the bypass valve 94 shown in FIGS. 3 and 4 functions as a main element of the control mechanism. The bypass valve 93 connected to the

refrigerant circuits

11a and 11b opens a refrigerant flow path for bypassing the compressor 12 when the pressure difference between the refrigerant before and after being compressed by the compressor 12 reaches the second value. open. When the pressure difference between the refrigerant before and after being compressed by the compression element 30 reaches the second value, the bypass valve 94 installed in the compression element 30 of the compressor 12 flows the refrigerant for bypassing the compression element 30. Open the road. Specifically, when the pressure difference between the refrigerant before and after being compressed by the compression element 30 reaches the second value, the bypass valve 94 is opened by the action of the spring 97, and thereby the suction path and the discharge in the cylinder 31 are discharged. The muffler 35 is communicated. For example, the second value is set to 3.5 to 4.5 MPa.

The

bypass valves

93 and 94 are opened when the pressure difference between the high pressure and the low pressure exceeds the second value to prevent the high pressure from rising. For example, the bypass valve 94 forms a bypass between the discharge muffler 35 of the compressor 12 and the suction portion of the cylinder 31, so that a high pressure can be reliably ensured even when the high-pressure conveyance path in the compressor 12 is blocked. Can be lowered.

In the second example, the

bypass valves

93 and 94 operate only while the pressure difference between the high pressure and the low pressure exceeds the second value. Therefore, the operation can be continued without impairing the operation state of the refrigeration cycle apparatus 10.

Next, a third example in which the third value is set as the threshold will be described.

FIG. 5 is an electrical connection diagram of the stator 41 and the pressure fuse 95 of the electric element 40 included in the compressor 12.

In the third example, the pressure switch 92 shown in FIGS. 1 and 2 or the pressure fuse 95 shown in FIGS. 3 and 5 functions as a main element of the control mechanism. The pressure switch 92 installed in the high-pressure piping of the

refrigerant circuits

11a and 11b mechanically stops the power supply to the compressor 12 when the refrigerant pressure on the high-pressure side of the

refrigerant circuits

11a and 11b reaches the third value. The pressure fuse 95 installed in the electric element 40 of the compressor 12 stops power supply to the electric element 40 when the refrigerant pressure on the high pressure side of the

refrigerant circuits

11a and 11b reaches the third value. Specifically, when the pressure of the refrigerant on the high-pressure side of the

refrigerant circuits

11a and 11b reaches the third value, the pressure fuse 95 interrupts energization between the electric element 40 and the external power source. The third value is set to a value higher than the first value. For example, the third value is set to 5 to 6 MPa.

The pressure fuse 95 is more preferable than the pressure switch 92 because it can operate even when the discharge pipe 22 of the compressor 12 is closed. As the pressure fuse 95, it is preferable to use an automatic return type. As shown in FIG. 5, the pressure fuse 95 stops the current flow to the electric element 40 by interrupting the neutral point of the three-phase stator winding 44 connected by the Y connection. Thereby, the operation of the compressor 12 can be stopped.

In the third example, since the compressor 12 is stopped, the operating state of the refrigeration cycle apparatus 10 cannot be maintained. However, safety can be ensured in a state in which the refrigeration cycle apparatus 10 can be restored.

Next, a fourth example in which the fourth value is set as the threshold will be described.

In the fourth example, the control device 17 shown in FIGS. 1 and 2 and the relief valve 96 shown in FIG. 3 function as main elements of the control mechanism. The relief valve 96 is used to discharge the refrigerant out of the sealed container 20 of the compressor 12. The control device 17 opens the relief valve 96 when the refrigerant pressure on the high pressure side of the

refrigerant circuits

11a and 11b reaches the fourth value. The fourth value is set to a value higher than the third value. For example, the fourth value is set to 5.5 to 6.5 MPa.

In the fourth example, the refrigerant is discharged outside the refrigeration cycle. Therefore, the refrigeration cycle apparatus 10 cannot perform normal operation thereafter. However, safety can be ensured more reliably.

As described above, by using two or more of the four mounting examples from the first example to the fourth example, more reliable protection can be achieved. The operation priority of the four implementation examples is highest in the first example, and decreases in the order of the second example, the third example, and the fourth example. Thereby, in the initial stage, protection can be applied by means having little influence on the operating state. When a clear abnormality occurs in the refrigeration cycle apparatus 10 such as a sensor abnormality, the operation of the refrigeration cycle apparatus 10 can be stopped.

As described above, according to the present embodiment, the diffusion of the disproportionation reaction of HFO-1123 can be prevented. Therefore, it is possible to prevent an explosion due to a disproportionation reaction of the refrigerant containing HFO-1123.

As mentioned above, although embodiment of this invention was described, you may implement this embodiment partially. For example, any one or some of the elements denoted by reference numerals in each drawing may be omitted or replaced with another element. In addition, this invention is not limited to this embodiment, A various change is possible as needed.

10 refrigeration cycle apparatus, 11a, 11b refrigerant circuit, 12 compressor, 13 four-way valve, 14 outdoor heat exchanger, 15 expansion valve, 16 indoor heat exchanger, 17 control device, 20 sealed container, 21 suction pipe, 22 discharge pipe , 23 Suction muffler, 24 Power supply terminal, 30 Compression element, 31 Cylinder, 32 Rolling piston, 33 Main bearing, 34 Sub bearing, 35 Discharge muffler, 40 Electric element, 41 Stator, 42 Rotor, 43 Stator core, 44 Stator winding, 45 lead wire, 46 rotor core, 48 insulation member, 50 shaft, 51 eccentric shaft portion, 52 main shaft portion, 53 subshaft portion, 91 pressure sensor, 92 pressure switch, 93 bypass valve, 94 bypass valve , 95 pressure fuse, 96 relief valve, 97 spring.

Claims

A refrigerant circuit in which a compressor, a first heat exchanger, an expansion mechanism, and a second heat exchanger are connected, and a refrigerant containing 1,1,2-trifluoroethylene circulates;
A refrigeration cycle apparatus comprising: a control mechanism that controls a pressure of the refrigerant in a flow path from the compressor to the expansion mechanism of the refrigerant circuit to be equal to or less than a threshold value.
The said control mechanism reduces the rotation speed of the electric element of the said compressor, when the pressure of the said refrigerant | coolant in the flow path from the said compressor of the said refrigerant circuit to the said expansion mechanism reaches a 1st value. Item 2. The refrigeration cycle apparatus according to item 1.
The control mechanism opens the refrigerant flow path for bypassing the compression element of the compressor when the pressure difference between the refrigerant before and after being compressed by the compression element of the compressor reaches a second value. The refrigeration cycle apparatus according to claim 1 or 2, wherein a bypass valve is provided in the compressor.
The control mechanism is connected to the refrigerant circuit, and when the pressure difference between the refrigerant before and after being compressed by the compressor reaches a second value, a flow path of the refrigerant for bypassing the compressor The refrigeration cycle apparatus according to any one of claims 1 to 3, further comprising an open bypass valve.
The control mechanism stops power supply to the electric element of the compressor when the pressure of the refrigerant in the flow path from the compressor to the expansion mechanism of the refrigerant circuit reaches a third value. The refrigeration cycle apparatus according to claim 1, 3 or 4.
When the pressure of the refrigerant in the flow path from the compressor to the expansion mechanism of the refrigerant circuit reaches a third value higher than the first value, the control mechanism supplies power to the electric element of the compressor. The refrigeration cycle apparatus according to claim 2, wherein the refrigeration cycle apparatus is stopped.
When the refrigerant pressure in the flow path from the compressor to the expansion mechanism of the refrigerant circuit reaches the third value, the control mechanism interrupts energization between the electric element of the compressor and an external power source. The refrigeration cycle apparatus according to claim 5 or 6, wherein the compressor is provided with a pressure fuse.
The control mechanism includes a relief valve for discharging the refrigerant to the outside of the compressor container, and the pressure of the refrigerant in a flow path from the compressor to the expansion mechanism of the refrigerant circuit. The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein when the pressure reaches a fourth value, the relief valve is opened.
The control mechanism includes a relief valve for discharging the refrigerant to the outside of the compressor container, and the pressure of the refrigerant in a flow path from the compressor to the expansion mechanism of the refrigerant circuit. The refrigeration cycle apparatus according to any one of claims 5 to 7, wherein when the first value reaches a fourth value higher than the third value, the relief valve is opened.
10. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant is 1,1,2-trifluoroethylene.
10. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant is a mixture containing 1% or more of 1,1,2-trifluoroethylene.