Refrigeration cycle equipment

Abstract

To provide a refrigeration cycle system that can prevent refrigerant leakage from the high-pressure side to the low-pressure side of the compression chamber, and can prevent liquid compression by ensuring sufficient superheating of the refrigerant drawn into the compressor. [Solution] The compressor comprises an electric motor unit and a compression mechanism unit in a sealed container, the electric motor unit and the compression mechanism unit are connected by a shaft 40, the compression mechanism unit 30 has a cylinder 31, a piston 32 disposed inside the cylinder 31 and vanes 33 partitioning the inside of the cylinder 31, the shaft 40 has an eccentric portion 42, the cylinder 31 has a vane groove 36 for arranging the vanes 33, the eccentric portion 42 is disposed inside the cylinder 31, the piston 32 is fitted into the eccentric portion 42, the vanes 33 operate without separating from the piston 32, and the control unit controls the pressure reducing device so that the degree of overheating is smaller when the compressor is rotating at a low rotation speed than when it is rotating at a high rotation speed.

Description

Technical Field

[0001] The present invention relates to a refrigeration cycle device using a compressor in which a vane operates without separating from a piston.

Background Art

[0002] The rotary compressor disclosed in Patent Document 1 has a configuration in which a piston and a vane that partitions a compression chamber and a suction chamber in a cylinder are integrally provided. The protruding tip portion of the vane is received in a receiving groove of a cylindrical support body that rotatably supports it, and the receiving groove penetrates from one side to the other side of the outer peripheral surface. Therefore, since the piston and the vane do not repeatedly separate and contact, the refrigeration machine oil does not deteriorate or hydrolyze, sludge does not occur and adhere to the refrigeration cycle, and a highly reliable refrigeration cycle device can be provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the piston and the vane are integrally configured, when liquid refrigerant is supplied to the compressor, liquid compression occurs because the refrigerant does not leak from the high-pressure side to the low-pressure side in the compression chamber, and a large load is applied to the vane, which may cause the vane or the components constituting the compressor to break. Also, even during low-speed operation of the compressor, the refrigerant cannot leak from the high-pressure side to the low-pressure side, so the compression load does not decrease and the rotational operation may become unstable.

[0005] Therefore, the present invention aims to provide a refrigeration cycle device that can prevent refrigerant leakage from the high-pressure side to the low-pressure side of the compression chamber, and can prevent liquid compression by ensuring sufficient superheating of the refrigerant drawn into the compressor. [Means for solving the problem]

[0006] The refrigeration cycle apparatus of the present invention as described in claim 1 is a refrigeration cycle apparatus comprising a compressor 1, a utilization-side heat exchanger 2, a pressure reducing device 3, and a heat source-side heat exchanger 4, all connected in a ring by refrigerant piping 5, and a control unit 80 that adjusts the amount of refrigerant circulated by controlling the rotational speed of the compressor 1 and the throttling amount of the pressure reducing device 3, wherein the compressor 1 comprises an electric motor unit 20 and a compression mechanism unit 30 within a sealed container 10, the electric motor unit 20 and the compression mechanism unit 30 are connected by a shaft 40, and the compression mechanism unit 30 comprises a cylinder 31 and a unit disposed within the cylinder 31 The compressor 1 has a piston 32 and vanes 33 that partition the inside of the cylinder 31, the shaft 40 has an eccentric portion 42, the cylinder 31 has a vane groove 36 for arranging the vanes 33, the eccentric portion 42 is arranged inside the cylinder 31, the piston 32 is fitted into the eccentric portion 42, the vanes 33 operate without separating from the piston 32, and the control unit 80 controls the pressure reducing device 3 so that the degree of superheating is smaller when the rotational speed of the compressor 1 is in the low rotational speed range than when it is in the high rotational speed range. The present invention as described in claim 2 is a refrigeration cycle apparatus as described in claim 1, comprising a detection unit 70 for detecting the temperature of the suction refrigerant drawn into the compressor 1 or the temperature of the discharge refrigerant discharged from the compressor 1, wherein the control unit 80 estimates the degree of superheating from the suction refrigerant temperature or the discharge refrigerant temperature detected by the detection unit 70, and controls the pressure reducing device 3 so that the degree of superheating falls within a preset target range. The present invention as described in claim 3 is characterized in that, in the refrigeration cycle device described in claim 2, the target superheat range is set according to the rotational speed range of the compressor 1. The present invention as described in claim 4 is characterized in that, in the refrigeration cycle device described in claim 1, the degree of superheating is set to zero when the rotational speed of the compressor 1 is in the lowest rotational speed range. The refrigeration cycle apparatus of the present invention as described in claim 5 is a refrigeration cycle apparatus comprising a compressor 1, a utilization-side heat exchanger 2, a pressure reducing device 3, and a heat source-side heat exchanger 4, all connected in a ring by refrigerant piping 5, and a control unit 80 that adjusts the amount of refrigerant circulating by controlling the rotational speed of the compressor 1 and the throttling amount of the pressure reducing device 3, wherein the compressor 1 comprises an electric motor unit 20 and a compression mechanism unit 30 within a sealed container 10, the electric motor unit 20 and the compression mechanism unit 30 are connected by a shaft 40, and the compression mechanism unit 30 comprises a cylinder 31 and a piston 32 disposed within the cylinder 31, The cylinder 31 has vanes 33 that partition the inside of the cylinder 31, the shaft 40 has an eccentric portion 42, the cylinder 31 has a vane groove 36 for arranging the vanes 33, the eccentric portion 42 is arranged inside the cylinder 31, the piston 32 is fitted into the eccentric portion 42, the vanes 33 operate without separating from the piston 32, and the control unit 80 controls the pressure reducing device 3 so that the high and low pressure difference of the refrigerant before and after the pressure reducing device 3 is smaller when the rotational speed of the compressor 1 is in the low rotational speed range than when it is in the high rotational speed range. The present invention as described in claim 6 is a refrigeration cycle apparatus as described in claim 5, further comprising a detection unit 70 for detecting the high-pressure side temperature or high-pressure side pressure of the refrigerant upstream of the pressure reducing device 3, and the low-pressure side temperature or low-pressure side pressure of the refrigerant downstream of the pressure reducing device 3, wherein the control unit 80 controls the pressure reducing device 3 so that the high-low pressure difference of the refrigerant detected by the detection unit 70 falls within a preset target high-low pressure difference range. The present invention as described in claim 7 is characterized in that, in the refrigeration cycle apparatus described in claim 6, the target high and low pressure difference range is set according to the rotational speed range of the compressor 1. The present invention as described in claim 8 is characterized in that, in the refrigeration cycle device described in claim 5, the high-low pressure difference is minimized when the rotational speed of the compressor 1 is in the lowest rotational speed range. [Effects of the Invention]

[0007] According to the present invention, since the vanes operate without separating from the piston, leakage of refrigerant from the high-pressure side to the low-pressure side of the compression chamber can be prevented. Furthermore, when the compressor rotation speed is in the low rotation speed range, the amount of refrigerant circulated decreases, which reduces the amount of liquid return. As a result, liquid compression can be prevented even with a low degree of heating, and operation can be performed with high efficiency by reducing the degree of superheating. [Brief explanation of the drawing]

[0008] [Figure 1] A configuration diagram showing a refrigeration cycle device according to one embodiment of the present invention. [Figure 2] Cross-sectional view showing the compressor used in the refrigeration cycle system according to this embodiment. [Figure 3] (a) A view of the compressor shown in Figure 2, along the line AA; (b) A perspective view of the same compressor with the piston and vanes separated. [Figure 4] Flowchart showing refrigerant flow path switching control of a refrigeration cycle system according to this embodiment. [Figure 5] This diagram illustrates the control of the superheating degree or high / low pressure difference of the refrigeration cycle system according to this embodiment. [Modes for carrying out the invention]

[0009] The refrigeration cycle device according to the first embodiment of the present invention comprises a compressor having an electric motor section and a compression mechanism section in a sealed container, the electric motor section and the compression mechanism section connected by a shaft, the compression mechanism section having a cylinder, a piston disposed in the cylinder, and vanes partitioning the inside of the cylinder, the shaft having an eccentric section, the cylinder having vane grooves for arranging the vanes, the eccentric section being located inside the cylinder, the piston being fitted into the eccentric section, the vanes operating without separating from the piston, and the control unit controlling the pressure reducing device so that the degree of superheating is smaller when the compressor rotation speed is in the low rotation speed range than when it is in the high rotation speed range.According to this embodiment, since the vanes operate without separating from the piston, leakage of refrigerant from the high-pressure side to the low-pressure side of the compression chamber can be prevented.In addition, according to this embodiment, when the compressor rotation speed is in the low rotation speed range, the amount of refrigerant circulation decreases, so the amount of liquid return decreases, which prevents liquid compression even with a lower degree of heating, and by reducing the degree of superheating, operation can be performed with high efficiency.

[0010] A second embodiment of the present invention provides a refrigeration cycle device according to the first embodiment, further comprising a detection unit for detecting the temperature of the suction refrigerant drawn into the compressor or the temperature of the discharge refrigerant discharged from the compressor, and a control unit for estimating the degree of superheating from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit, and controlling the pressure reducing device so that the degree of superheating falls within a preset target superheating range. According to this embodiment, by controlling the degree of superheating to fall within the target superheating range, liquid compression can be prevented and highly efficient operation can be achieved.

[0011] A third embodiment of the present invention is a refrigeration cycle device according to the second embodiment, wherein the target superheat range is set according to the rotational speed range of the compressor. According to this embodiment, by setting the target superheat range according to the rotational speed range of the compressor, liquid compression can be prevented and highly efficient operation can be achieved.

[0012] A fourth embodiment of the present invention is a refrigeration cycle device according to the first embodiment, wherein the degree of superheating is set to zero when the compressor rotation speed is in the lowest rotation speed range. According to this embodiment, when the degree of superheating is zero, the refrigerant is in a wet state and contains liquid refrigerant, but when the compressor rotation speed is in the lowest rotation speed range, the load due to liquid compression is small and the vanes are not damaged, and because the compression ratio is reduced by setting the degree of superheating to zero, the device can be operated at high efficiency.

[0013] The fifth embodiment of the refrigeration cycle device of the present invention comprises a compressor comprising an electric motor unit and a compression mechanism unit in a sealed container, the electric motor unit and the compression mechanism unit connected by a shaft, the compression mechanism unit having a cylinder, a piston disposed in the cylinder, and vanes partitioning the inside of the cylinder, the shaft having an eccentric portion, the cylinder having vane grooves for arranging the vanes, the eccentric portion being located inside the cylinder, the piston being fitted into the eccentric portion, the vanes operating without separating from the piston, and the control unit controlling the pressure reducing device so that the high and low pressure difference of the refrigerant before and after the pressure reducing device is smaller when the compressor rotation speed is in the low rotation speed range than when it is in the high rotation speed range.According to this embodiment, since the vanes operate without separating from the piston, leakage of refrigerant from the high-pressure side to the low-pressure side of the compression chamber can be prevented.In addition, according to this embodiment, when the compressor rotation speed is in the low rotation speed range, the amount of refrigerant circulation decreases and the amount of liquid return decreases, so liquid compression can be prevented even if the high and low pressure difference of the refrigerant before and after the pressure reducing device is small, and by reducing the high and low pressure difference of the refrigerant before and after the pressure reducing device, operation can be performed with high efficiency. Furthermore, according to this embodiment, when the compressor rotation speed is in the low rotation speed range, the compression load can be reduced and the stability of the compressor rotation can be ensured by reducing the high and low pressure difference of the refrigerant before and after the pressure reducing device.

[0014] The sixth embodiment of the present invention is a refrigeration cycle apparatus according to the fifth embodiment, which includes a detection unit that detects the high-pressure side temperature or high-pressure side pressure of the refrigerant upstream of the decompression device and the low-pressure side temperature or low-pressure side pressure of the refrigerant downstream of the decompression device. The control unit controls the decompression device so that the high and low pressure difference of the refrigerant detected by the detection unit falls within a preset target high and low pressure difference range. According to this embodiment, by controlling the high and low pressure difference to fall within the target high and low pressure difference range, it is possible to prevent liquid compression, ensure high-efficiency operation, and ensure the stability of the compressor rotation.

[0015] The seventh embodiment of the present invention is a refrigeration cycle apparatus according to the sixth embodiment, in which the target high and low pressure difference range is set according to the rotation speed range of the compressor. According to this embodiment, by setting the target high and low pressure difference range according to the rotation speed range of the compressor, it is possible to prevent liquid compression, ensure high-efficiency operation, and ensure the stability of the compressor rotation.

[0016] The eighth embodiment of the present invention is a refrigeration cycle apparatus according to the fifth embodiment, in which the high and low pressure difference is minimized when the rotation speed of the compressor is in the lowest rotation speed range. According to this embodiment, although the high and low pressure difference of the refrigerant before and after the decompression device becomes small and liquid refrigerant may be mixed, if the rotation speed of the compressor is in the lowest rotation speed range, the load due to liquid compression is small and the vane will not be damaged. Since the high and low pressure difference of the refrigerant becomes small, it can be operated with high efficiency, and the stability of the compressor rotation can be ensured.

Example

[0017] FIG. 1 is a configuration diagram showing a refrigeration cycle apparatus according to an embodiment of the present invention. The refrigeration cycle apparatus according to this embodiment includes a compressor 1, a utilization-side heat exchanger 2, a decompression device 3, and a heat source-side heat exchanger 4, which are annularly connected by a refrigerant pipe 5. A receiver 6 for storing a part of the refrigerant flowing through the refrigerant pipe 5 is provided in the refrigerant pipe 5. The receiver 6 is preferably provided in the refrigerant pipe 5 between the user-side heat exchanger 2 and the decompression device 3. The receiver 6 is a sealed container, and the receiver internal volume of the receiver 6 is made larger than the difference between the user-side heat exchange volume of the user-side heat exchanger 2 and the heat source-side heat exchange volume of the heat source-side heat exchanger 4.

[0018] In the refrigeration cycle device according to the present embodiment, a four-way valve 7 is provided in the refrigerant pipe 5. The four-way valve 7 switches the refrigerant discharged from the compressor 1 so as to flow into the user-side heat exchanger 2 or the heat source-side heat exchanger 4. When the four-way valve 7 causes the refrigerant discharged from the compressor 1 to flow into the user-side heat exchanger 2, the refrigerant discharged from the compressor 1 flows through the user-side heat exchanger 2, the decompression device 3, and the heat source-side heat exchanger 4, and then is returned to the compressor 1 by the four-way valve 7. When the four-way valve 7 causes the refrigerant discharged from the compressor 1 to flow into the heat source-side heat exchanger 4, the refrigerant discharged from the compressor 1 flows through the heat source-side heat exchanger 4, the decompression device 3, and the user-side heat exchanger 2, and then is returned to the compressor 1 by the four-way valve 7.

[0019] The refrigerant pipe 5 includes a refrigerant discharge pipe 5a connecting the discharge pipe 13 (see FIG. 2) of the compressor 1 and the four-way valve 7, a first refrigerant pipe 5b connecting the four-way valve 7 and the user-side heat exchanger 2, a second refrigerant pipe 5c1 connecting the user-side heat exchanger 2 and the receiver 6, a third refrigerant pipe 5c2 connecting the receiver 6 and the decompression device 3, a fourth refrigerant pipe 5d connecting the decompression device 3 and the heat source-side heat exchanger 4, a fifth refrigerant pipe 5e connecting the heat source-side heat exchanger 4 and the four-way valve 7, and a refrigerant suction pipe 5f connecting the four-way valve 7 and the suction pipe 12 (see FIG. 2) of the compressor 1. The refrigerant suction pipe 5f has an accumulator 14. Further, a refrigerant flow path switching valve 8 is provided in the refrigerant pipe 5 (refrigerant suction pipe 5f) located upstream of the suction pipe 12 of the compressor 1.

[0020] The refrigeration cycle device according to the present embodiment includes a heat storage tank 60 using the compressor 1 as a heat source. The heat storage tank 60 is installed around the compressor 1 so as to surround it, and absorbs the heat generated from the compressor 1. The heat storage tank 60 has a heat storage material, such as an aqueous solution of ethylene glycol, and stores the heat from the sealed container 10 of the compressor 1 in the heat storage material. Then, it supplies the heat stored in the heat storage material to the heat exchange circuit 61. It is preferable that the heat storage tank 60 has a heat source other than the compressor 1, such as a heater. The heat exchange circuit 61 has an inner pipe through which the refrigerant passes, and it is preferable that the inner pipe that exchanges heat with the heat storage material in the heat storage tank 60 has grooves or irregularities formed on at least one of its inner surface and outer surface. By forming grooves or irregularities on the inner surface and outer surface of the inner pipe, the heat transfer coefficient can be improved and heat exchange from the heat storage tank 60 to the refrigerant flowing through the inner pipe can be promoted. The refrigerant flow path switching valve 8 switches between a heat exchange circuit 61 that performs heat exchange in the heat storage tank 60 and guides the refrigerant to the suction pipe 12, and a refrigerant suction pipe 5f that guides the refrigerant to the suction pipe 12 without passing through the heat exchange circuit 61.

[0021] The refrigeration cycle device according to this embodiment is equipped with one of the following detection units 70: a detection unit 70a for detecting the temperature or pressure of the refrigerant flowing through the refrigerant discharge pipe 5a; a detection unit 70b for detecting the temperature or pressure of the refrigerant flowing through the first refrigerant pipe 5b; a detection unit 70c for detecting the temperature or pressure of the refrigerant flowing through the second refrigerant pipe 5c1 or the third refrigerant pipe 5c2; a detection unit 70d for detecting the temperature or pressure of the refrigerant flowing through the fourth refrigerant pipe 5d; a detection unit 70e for detecting the temperature or pressure of the refrigerant flowing through the fifth refrigerant pipe 5e; and a detection unit 70f for detecting the temperature or pressure of the refrigerant flowing through the refrigerant suction pipe 5f. The refrigeration cycle device according to this embodiment has a control unit 80, which controls the rotational speed (frequency) of the compressor 1, the opening degree of the pressure reducing device 3, the switching of the four-way valve 7, and the switching of the refrigerant flow path switching valve 8 based on the detected value from the detection unit 70 and the instruction data from the input means.

[0022] The ends of the second refrigerant pipe 5c1 and the third refrigerant pipe 5c2 are inserted into the receiver 6 from the bottom. The receiver 6, which is a sealed container, has a refrigerant introduction pipe for introducing refrigerant into the receiver 6 and a refrigerant discharge pipe for discharging refrigerant from the receiver 6, both inserted vertically upward from the bottom of the container. By inserting the refrigerant introduction pipe and the refrigerant discharge pipe vertically upward from the bottom of the container in this way, the liquid refrigerant inside the container does not flow out of the refrigerant discharge pipe due to inertia, thereby preventing the inflow of liquid refrigerant into the compressor 1 and preventing a decrease in the reliability of the compressor 1 due to liquid backflow. In the heating operation mode and the forward cycle defrosting operation mode, the second refrigerant pipe 5c1 becomes the refrigerant inlet pipe, and the third refrigerant pipe 5c2 becomes the refrigerant outlet pipe. Furthermore, in the cooling operation mode and the reverse cycle defrosting operation mode, the third refrigerant pipe 5c2 becomes the refrigerant inlet pipe, and the second refrigerant pipe 5c1 becomes the refrigerant outlet pipe.

[0023] As shown in Figure 1, the receiver 6 is installed in the refrigerant piping 5 between the user-side heat exchanger 2 and the pressure reducing device 3. By making the internal volume of the heat source-side heat exchanger larger than the internal volume of the user-side heat exchanger, when the user-side heat exchanger 2 operates as a condenser, if the internal volume of the user-side heat exchanger is smaller than the internal volume of the heat source-side heat exchanger, the amount of refrigerant circulated will be excessive. However, by installing the receiver 6 in the refrigerant piping 5 between the user-side heat exchanger 2 and the pressure reducing device 3, liquid refrigerant can be stored in the receiver 6, ensuring a more reliable superheating of the refrigerant drawn into the compressor 1 and preventing a decrease in the reliability of the compressor 1 due to liquid return.

[0024] As shown in Figure 1, the receiver 6, which is a sealed container, has a refrigerant pipe 5c1 connected to the heat exchanger 2 (second refrigerant pipe) and a refrigerant pipe 5c2 connected to the pressure reducing device 3 (third refrigerant pipe), inserted vertically upward from the bottom of the container. The open end of the refrigerant pipe 5c2 is positioned higher than the open end of the refrigerant pipe 5c1 (second refrigerant pipe), preventing the liquid refrigerant supplied from the heat exchanger 2 from flowing directly into the pressure reducing device 3. This ensures a more reliable superheating of the refrigerant drawn into the compressor 1 and prevents a decrease in the reliability of the compressor 1 due to liquid backflow.

[0025] Unlike the refrigeration cycle system shown in Figure 1, the receiver 6 can also be installed in the fourth refrigerant piping 5d between the heat source side heat exchanger 4 and the pressure reducing device 3. In this case, the internal volume of the heat exchanger on the utilization side of the utilization side heat exchanger 2 is made larger than the internal volume of the heat exchanger on the heat source side of the heat source side heat exchanger 4. When the heat source side heat exchanger 4 operates as a condenser, if the internal volume of the heat source side heat exchanger is smaller than the internal volume of the utilization side heat exchanger, the refrigerant circulation rate will be excessive. However, by providing a receiver 6 in the fourth refrigerant pipe 5d between the heat source side heat exchanger 4 and the pressure reducing device 3, liquid refrigerant can be stored in the receiver 6, ensuring a more reliable superheating of the refrigerant drawn into the compressor 1 and preventing a decrease in the reliability of the compressor 1 due to liquid return. Furthermore, when the receiver 6 is installed in the fourth refrigerant piping 5d between the heat source side heat exchanger 4 and the pressure reducing device 3, the heat source heat exchanger side connecting refrigerant piping connected to the heat source side heat exchanger 4 and the pressure reducing device side connecting refrigerant piping connected to the pressure reducing device 3 are inserted vertically upward from the bottom of the sealed container, the receiver 6, and the open end of the pressure reducing device side connecting refrigerant piping is positioned higher than the open end of the heat source heat exchanger side connecting refrigerant piping. By inserting the heat source heat exchanger side connecting refrigerant piping and the pressure reducing device side connecting refrigerant piping vertically upward from the bottom of the container, and further positioning the open end of the pressure reducing device side connecting refrigerant piping higher than the open end of the heat source heat exchanger side connecting refrigerant piping, the liquid refrigerant supplied from the heat source side heat exchanger 4 does not flow directly into the pressure reducing device 3, the superheating of the refrigerant suctioned to the compressor 1 can be more reliably ensured, and the reliability of the compressor 1 can be prevented from decreasing due to liquid backflow.

[0026] The refrigeration cycle device according to this embodiment has a heating operation mode, a cooling operation mode, a forward cycle defrosting operation mode, and a reverse cycle defrosting operation mode as operating modes. In heating operation mode, the refrigerant is sequentially passed through the compressor 1, the user-side heat exchanger 2, the pressure reducing device 3, and the heat source-side heat exchanger 4, so that the user-side heat exchanger 2 acts as a condenser and the heat source-side heat exchanger 4 acts as an evaporator. In cooling operation mode, the refrigerant is sequentially passed through the compressor 1, the heat source side heat exchanger 4, the pressure reducing device 3, and the utilization side heat exchanger 2, so that the utilization side heat exchanger 2 acts as an evaporator and the heat source side heat exchanger 4 acts as a condenser. In the forward cycle defrosting operation mode, refrigerant is sequentially supplied to the compressor 1, the user-side heat exchanger 2, the pressure reducing device 3, and the heat source-side heat exchanger 4, and the pressure reducing device 3 is fully opened, thereby using the user-side heat exchanger 2 and the heat source-side heat exchanger 4 as condensers. By using the user-side heat exchanger 2 and the heat source-side heat exchanger 4 as condensers, defrosting of the heat source-side heat exchanger 4 is performed while heating by the user-side heat exchanger 2 continues. In the reverse cycle defrosting operation mode, refrigerant is passed sequentially through the compressor 1, the heat source side heat exchanger 4, the pressure reducing device 3, and the utilization side heat exchanger 2, thereby using the heat source side heat exchanger 4 as a condenser and defrosting the heat source side heat exchanger 4.

[0027] Figure 2 is a cross-sectional view showing a compressor used in the refrigeration cycle device according to this embodiment, Figure 3(a) is a view of the compressor shown in Figure 2 along line AA, and Figure 3(b) is a perspective view of the same compressor with the piston and vanes separated.

[0028] As shown in Figure 2, the compressor 1 comprises an electric motor unit 20 and a compression mechanism unit 30 within a sealed container 10. The electric motor unit 20 and the compression mechanism unit 30 are connected by a shaft 40. The motor unit 20 consists of a stator 21 fixed to the inner surface of the sealed container 10 and a rotor 22 that rotates within the stator 21. The compression mechanism 30 includes a cylinder 31, a piston 32 positioned inside the cylinder 31, and vanes 33 (see Figure 3) that divide the inside of the cylinder 31. An upper bearing 51 is positioned on one side of the cylinder 31, and a lower bearing 52 is positioned on the other side of the cylinder 31. The shaft 40 consists of a main shaft portion 41 to which the rotor 22 is attached and which is supported by an upper bearing 51, an eccentric portion 42 to which the piston 32 is attached, and a secondary shaft portion 43 supported by a lower bearing 52. The upper bearing 51 is fixed to the sealed container 10. The piston 32 is fitted to the eccentric portion 42 of the shaft 40 that passes through the cylinder 31 so as to be able to rotate. An upper cover 53 is provided on the upper part of the upper bearing 51. A sound-dampening chamber 54 is formed between the upper bearing 51 and the upper cover 53. High-pressure refrigerant gas compressed by the compression mechanism 30 is discharged into the sound-dampening chamber 54. The high-pressure refrigerant gas discharged into the sound-dampening chamber 54 is then discharged into the sealed container 10.

[0029] An oil reservoir 11 is formed at the bottom of the sealed container 10. The oil reservoir 11 stores refrigerant oil. An axial shaft oil supply passage 46 is formed inside the shaft 40. A connecting passage 47 for supplying refrigerant oil to the sliding surface of the compression mechanism 30 is formed inside the eccentric portion 42. The refrigerant oil in the oil reservoir 11 is introduced into the internal oil supply passage 46 of the shaft from the lower end of the shaft 40. A portion of the refrigerant oil introduced into the internal oil supply passage 46 is supplied to the sliding surface of the compression mechanism 30 from the connecting passage 47. An intake pipe 12 is connected to the side of the sealed container 10, and a discharge pipe 13 is connected to the top surface of the sealed container 10. The intake pipe 12 guides the refrigerant to the compression mechanism 30. The discharge pipe 13 guides the refrigerant, which has been compressed in the compression mechanism 30 and discharged into the sealed container 10, to the outside of the sealed container 10. An accumulator 14 is provided on the upstream side of the suction tube 12.

[0030] The accumulator 14 comprises an outer cylinder 14a, a refrigerant suction pipe 14b, and a separator plate 14c. The upper part of the outer cylinder 14a has an outer cylinder inlet 14d for introducing refrigerant from the evaporator 4. The refrigerant suction pipe 14b has a suction pipe inlet 14e inside the outer cylinder 14a. The separator plate 14c is positioned between the outer cylinder inlet 14d and the suction pipe inlet 14e. A liquid reservoir 14f is formed at the inner bottom of the outer cylinder 14a. The liquid refrigerant is stored in the liquid reservoir 14f. The liquid refrigerant can be stored up to the height H of the suction pipe inlet 14e. Therefore, the volume of the liquid reservoir 14f is equal to the height H of the suction pipe inlet 14e. The compressor 1 is driven by an inverter at multiple operating frequencies, and is driven in a low-speed range where the rotational speed of the motor unit 20 decreases, or in a high-speed range where the rotational speed of the motor unit 20 increases.

[0031] The compression chamber 34 shown in Figure 3(a) is formed between the upper bearing 51 and the lower bearing 52, between the inner circumferential surface of the cylinder 31 and the outer circumferential surface of the piston 32. The suction tube 12 is connected to the suction passage 35 of the compression mechanism 30. The intake passage 35 is connected to the compression chamber 34. The rotation of the shaft 40 causes the piston 32 to revolve around the earth. The vane 33 reciprocates in the vane groove 36 by a piston 32 that revolves along the inner wall surface of the cylinder 31. The compression chamber 34 is divided by the vane 33 into an intake space 34a that communicates with the intake passage 35 and a compression space 34b that communicates with the discharge hole 37. The intake volume formed in the cylinder 31 is the volume of the intake space 34a when the intake passage 35 is closed by the piston 32, and is the volume when the intake space 34a is at its maximum size. The revolving motion of the piston 32 draws the gaseous refrigerant from the suction pipe 12 through the suction passage 35 into the compression chamber 34. After being compressed in the compression chamber 34, the gaseous refrigerant is discharged from the discharge port 37 into the silencer chamber 54. The refrigerant gas discharged into the soundproofing chamber 54 is discharged into the sealed container 10 and then discharged outside the sealed container 10 through the discharge pipe 13. The high-pressure refrigerant gas discharged outside the sealed container 10 passes through the condenser 2, the pressure reducing device 3, and the evaporator 4, becoming low-pressure refrigerant gas and returning to the compression mechanism 30 via the accumulator 14.

[0032] As shown in Figure 3(a), a cylindrical groove 32a with an arc angle exceeding 180° is formed on the outer circumferential surface of the piston 32. The cylindrical groove 32a extends from one end face to the other end face of the piston 32. The vane 33 has a vane side portion 33a that slides with the vane groove 36, a cylindrical portion 33b that is positioned in the cylindrical groove 32a, and a constricted portion 33c that connects the vane side portion 33a and the cylindrical portion 33b. The cylindrical portion 33b is formed at the end of the vane 33. By engaging the cylindrical portion 33b with the cylindrical groove 32a, the vane 33 operates without separating from the piston 32. The piston 32 and the vane 33 may be integrally formed.

[0033] Figure 4 is a flowchart showing the refrigerant flow path switching control of the refrigeration cycle device according to this embodiment. If the operating mode is the heating operation mode (S1), the control unit 80 connects the fifth refrigerant pipe 5e and the refrigerant suction pipe 5f using the refrigerant flow path switching valve 8, and flows the refrigerant from the fifth refrigerant pipe 5e into the refrigerant suction pipe 5f (S2). If the degree of superheating estimated from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 is above a threshold (No in S3), refrigerant is flowed into the refrigerant suction pipe 5f without switching the refrigerant flow path switching valve 8 (S2).

[0034] If the degree of superheating estimated from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 falls below a threshold (Yes in S3), the refrigerant flow path switching valve 8 is switched (S4), and the refrigerant from the fifth refrigerant pipe 5e is allowed to flow into the heat exchange circuit 61 (S5). If defrosting is not required (No in S6), the refrigerant from the fifth refrigerant pipe 5e is allowed to flow into the heat exchange circuit 61 without switching the refrigerant flow path switching valve 8 (S5). In this embodiment, when defrosting is not required (No in S6), the refrigerant from the fifth refrigerant pipe 5e is flowed into the heat exchange circuit 61. However, when defrosting is not required (No in S6), if the degree of superheating estimated from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 exceeds a threshold, the refrigerant flow path switching valve 8 is switched to allow refrigerant to flow into the refrigerant suction pipe 5f (S2).

[0035] When the detection unit 70 detects frost formation on the heat source side heat exchanger 4 and the control unit 80 determines that defrosting is necessary (Yes in S6), either forward cycle defrosting operation or reverse cycle defrosting operation is selected based on the detected frost formation state. If the control unit 80 selects the forward cycle defrosting operation mode (Yes in S7), it switches the refrigerant flow path switching valve 8 (S8) and performs defrosting operation with the refrigerant from the fifth refrigerant pipe 5e flowing into the heat exchange circuit 61 (S9). When the defrosting operation in the forward cycle defrosting mode is completed (Yes in S10), the refrigerant flow path switching valve 8 is switched (S8), and the operation returns to the heating mode (S1).

[0036] If the control unit 80 selects the reverse cycle defrosting operation mode (No in S7), it performs the defrosting operation with refrigerant flowing through the refrigerant suction pipe 5f without switching the refrigerant flow path switching valve 8 (S12). When the defrosting operation in reverse cycle defrosting mode is completed (Yes in S13), the operation returns to heating mode (S1).

[0037] As described above, in heating operation mode, if the degree of superheating estimated from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 is above a threshold, the refrigerant flow path switching valve 8 flows refrigerant into the refrigerant suction pipe 5f. If the degree of superheating is below the threshold, the refrigerant flow path switching valve 8 flows refrigerant into the heat exchange circuit 61. This ensures sufficient superheating of the refrigerant drawn into the compressor 1 when the degree of superheating is insufficient, such as at low ambient temperatures or when the compressor 1 is started up. This prevents damage to the vanes 33 due to the load caused by liquid compression and prevents a decrease in the reliability of the compressor 1 due to liquid compression. Furthermore, in heating operation mode, the refrigerant is directed to the refrigerant suction pipe 5f by the refrigerant flow path switching valve 8, and in forward cycle defrosting operation mode, the refrigerant is directed to the heat exchange circuit 61 by the refrigerant flow path switching valve 8. This ensures that the superheating of the refrigerant drawn into the compressor 1 is sufficiently maintained even in forward cycle defrosting operation mode, preventing damage to the vanes 33 due to the load caused by liquid compression, preventing a decrease in the reliability of the compressor 1 due to liquid compression, and improving defrosting performance at low ambient temperatures.

[0038] Figure 5 is an explanatory diagram illustrating the control of the superheating degree or high / low pressure difference of the refrigeration cycle device according to this embodiment. As shown in Figure 5(a), the degree of superheating (intake SH) can be estimated, for example, from the temperature difference between the intake temperature and the low-pressure temperature, and the high-low pressure difference is the difference between hc and hd. The control unit 80 controls the pressure reducing device 3 so that the degree of superheating is smaller when the compressor 1 is rotating at a low rotational speed than when it is rotating at a high rotational speed. In the refrigeration cycle device according to this embodiment, a detection unit 70 is provided to detect the temperature of the suction refrigerant drawn into the compressor 1 or the temperature of the discharge refrigerant discharged from the compressor 1. The control unit 80 estimates the degree of superheating from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 and controls the pressure reducing device 3 so that the degree of superheating falls within a preset target range. The target superheat range is set according to the rotational speed range of compressor 1.

[0039] As shown in Figure 5(b), for example, if the rotational speed ranges of the compressor 1 are the highest rotational speed range, the high rotational speed range, the medium rotational speed range, and the lowest rotational speed range, then the target superheat range in the highest rotational speed range is set to the range where the target superheat is at its maximum, the target superheat range in the high rotational speed range is set to the range where the target superheat is less than the maximum but greater than the medium, the target superheat range in the medium rotational speed range is set to the range where the target superheat is less than the large but greater than the minimum, and the target superheat range in the lowest rotational speed range is set to the range where the target superheat is at its minimum (zero).

[0040] Furthermore, the control unit 80 controls the pressure reducing device 3 so that the high and low pressure difference of the refrigerant before and after the pressure reducing device 3 becomes smaller when the compressor 1 is rotating at a low rotation speed than when it is rotating at a high rotation speed. In the refrigeration cycle system according to this embodiment, a detection unit 70 is provided to detect the high-pressure side temperature or high-pressure side pressure of the refrigerant upstream of the pressure reducing device 3, and the low-pressure side temperature or low-pressure side pressure of the refrigerant downstream of the pressure reducing device 3. The control unit 80 controls the pressure reducing device 3 so that the high-low pressure difference of the refrigerant detected by the detection unit 70 falls within a preset target high-low pressure difference range.

[0041] The target high and low pressure difference range is set according to the rotational speed range of compressor 1. As shown in Figure 5(b), for example, when the rotational speed range of compressor 1 is the maximum rotational speed range, high rotational speed range, medium rotational speed range, and minimum rotational speed range, the target high-low pressure difference range in the maximum rotational speed range is set to the range where the high-low pressure difference is maximum, the high-low pressure difference in the high rotational speed range is set to a range where the high-low pressure difference is smaller than the maximum but larger than the medium, the high-low pressure difference in the medium rotational speed range is set to a range where the high-low pressure difference is smaller than the large but larger than the minimum, and the high-low pressure difference in the minimum rotational speed range is set to the minimum.

[0042] As described above, the refrigeration cycle device according to this embodiment has a compressor 1 which comprises an electric motor unit 20 and a compression mechanism unit 30 in a sealed container 1010, the electric motor unit 20 and the compression mechanism unit 30 are connected by a shaft 40, the compression mechanism unit 30 has a cylinder 31, a piston 32 disposed inside the cylinder 31 and vanes 33 that partition the inside of the cylinder 31, the shaft 40 has an eccentric portion 42, the cylinder 31 has a vane groove 36 for arranging the vanes 33, the eccentric portion 42 is disposed inside the cylinder 31, the piston 32 is fitted into the eccentric portion 42, the vanes 33 operate without separating from the piston 32, a receiver 6 which stores a portion of the refrigerant flowing through the refrigerant piping 5 is provided in the refrigerant piping 5, the receiver volume of the receiver 6 is made larger than the difference between the volume of the heat exchanger on the utilization side of the heat exchanger 2 and the volume of the heat exchanger on the heat source side of the heat exchanger 4, thereby reducing the amount of liquid refrigerant drawn into the cylinder 31. In this embodiment, since the vane 33 operates without separating from the piston 32, leakage of refrigerant from the high-pressure side to the low-pressure side of the compression chamber 34 can be prevented. Furthermore, in this embodiment, by providing a receiver 6 in the refrigerant piping 5 that stores a portion of the refrigerant flowing through the refrigerant piping 5, refrigerant can be stored in the receiver 6 when there is an excess of refrigerant. This ensures that the superheating of the refrigerant drawn into the compressor 1 is sufficient, even at low ambient temperatures or when the compressor 1 is started up. This prevents damage to the vane 33 due to the load caused by liquid compression and prevents a decrease in the reliability of the compressor 1 due to liquid compression.

[0043] Furthermore, in this embodiment of the refrigeration cycle device, the receiver 6 is a sealed container, and the refrigerant introduction pipe for introducing refrigerant into the receiver 6 and the refrigerant discharge pipe for dischargering refrigerant from the receiver 6 are inserted vertically upward from the bottom of the container. This prevents the liquid refrigerant in the container from flowing out of the refrigerant discharge pipe due to inertia, thereby preventing the inflow of liquid refrigerant into the compressor 1 and preventing a decrease in the reliability of the compressor 1 due to liquid backflow.

[0044] Furthermore, in this embodiment of the refrigeration cycle system, the receiver 6 is provided in the refrigerant piping 5 between the utilization-side heat exchanger 2 and the pressure reducing device 3, and the internal volume of the heat source-side heat exchanger is made larger than the internal volume of the utilization-side heat exchanger. When the utilization-side heat exchanger 2 operates as a condenser, if the internal volume of the utilization-side heat exchanger is smaller than the internal volume of the heat source-side heat exchanger, the amount of refrigerant circulated will be excessive. However, by providing the receiver 6 in the refrigerant piping 5 between the utilization-side heat exchanger 2 and the pressure reducing device 3, liquid refrigerant can be stored in the receiver 6, ensuring a more reliable degree of superheating of the refrigerant drawn into the compressor 1, and preventing a decrease in the reliability of the compressor 1 due to liquid return.

[0045] Furthermore, in this embodiment of the refrigeration cycle device, the receiver 6 is a sealed container, and the refrigerant piping 5c1 connected to the heat exchanger 2 and the refrigerant piping 5c2 connected to the pressure reducing device 3 are inserted vertically upward from the bottom of the container, with the open end of the refrigerant piping 5c2 positioned higher than the open end of the refrigerant piping 5c1. By inserting the refrigerant piping 5c1 and the refrigerant piping 5c2 vertically upward from the bottom of the container, and further positioning the open end of the refrigerant piping 5c2 higher than the open end of the refrigerant piping, the liquid refrigerant supplied from the heat exchanger 2 does not flow directly to the pressure reducing device 3, ensuring a more reliable superheating of the refrigerant drawn into the compressor 1 and preventing a decrease in the reliability of the compressor 1 due to liquid backflow.

[0046] Furthermore, in this embodiment, the refrigeration cycle device is equipped with a receiver 6 in the fourth refrigerant piping 5d between the heat source side heat exchanger 4 and the pressure reducing device 3, and the volume of the heat exchanger on the utilization side is made larger than the volume of the heat exchanger on the heat source side. According to this embodiment, when the heat source side heat exchanger 4 operates as a condenser, if the volume of the heat exchanger on the heat source side is smaller than the volume of the heat exchanger on the utilization side, the amount of refrigerant circulated will be excessive. However, by providing a receiver 6 in the fourth refrigerant piping 5d between the heat source side heat exchanger 4 and the pressure reducing device 3, liquid refrigerant can be stored in the receiver 6, ensuring a more reliable degree of superheating of the refrigerant drawn into the compressor 1, and preventing a decrease in the reliability of the compressor 1 due to liquid return.

[0047] Furthermore, in this embodiment of the refrigeration cycle device, the receiver 6 is provided in the fourth refrigerant pipe 5d between the heat source side heat exchanger 4 and the pressure reducing device 3, the internal volume of the heat exchanger on the utilization side is made larger than the internal volume of the heat exchanger on the heat source side, the receiver 6 is a sealed container, the heat source heat exchanger side connecting refrigerant pipe connected to the heat source side heat exchanger 4 and the pressure reducing device side connecting refrigerant pipe connected to the pressure reducing device 3 are inserted vertically upward from the bottom of the container, and the open end of the pressure reducing device side connecting refrigerant pipe is positioned higher than the open end of the heat source heat exchanger side connecting refrigerant pipe. In this way, by inserting the refrigerant piping connected to the heat source heat exchanger side and the refrigerant piping connected to the pressure reducing device side vertically upward from the bottom of the container, and further positioning the open end of the refrigerant piping connected to the pressure reducing device side higher than the open end of the refrigerant piping connected to the heat source heat exchanger side, the liquid refrigerant supplied from the heat source heat exchanger 4 does not flow directly into the pressure reducing device 3, thereby more reliably ensuring the superheating degree of the refrigerant drawn into the compressor 1 and preventing a decrease in the reliability of the compressor 1 due to liquid backflow.

[0048] Furthermore, in this embodiment, the refrigeration cycle device comprises a compressor 1 with an electric motor unit 20 and a compression mechanism unit 30 inside a sealed container 10, the electric motor unit 20 and the compression mechanism unit 30 connected by a shaft 40, the compression mechanism unit 30 having a cylinder 31, a piston 32 disposed inside the cylinder 31 and vanes 33 partitioning the inside of the cylinder 31, the shaft 40 having an eccentric portion 42, the cylinder 31 having vane grooves 36 for arranging the vanes 33, and the eccentric portion 42 The assembly is located within the Linder 31, with a piston 32 fitted into an eccentric portion 42, and the vanes 33 operate without separating from the piston 32. It is equipped with a heat storage tank 60 that uses the compressor 1 as a heat source, and a refrigerant flow path switching valve 8 is provided in the refrigerant piping 5 located upstream of the suction pipe 12 of the compressor 1. The refrigerant flow path switching valve 8 switches between a heat exchange circuit 61 that performs heat exchange in the heat storage tank 60 and guides the refrigerant to the suction pipe 12, and a refrigerant suction pipe 5f that guides the refrigerant to the suction pipe 12 without passing through the heat exchange circuit 61. According to this embodiment, since the vanes 33 operate without separating from the piston 32, leakage of refrigerant from the high-pressure side to the low-pressure side of the compression chamber 34 can be prevented. Furthermore, according to this embodiment, by flowing the refrigerant through the heat exchange circuit 61 that performs heat exchange in the heat storage tank 60, the degree of superheating of the refrigerant drawn into the compressor 1 can be sufficiently ensured, preventing damage to the vanes 33 due to the load caused by liquid compression, and preventing a decrease in the reliability of the compressor 1 due to liquid compression.

[0049] Furthermore, the refrigeration cycle device according to this embodiment has a heating operation mode in which the user-side heat exchanger 2 is used as a condenser by sequentially flowing refrigerant through the compressor 1, user-side heat exchanger 2, pressure reducing device 3, and heat source-side heat exchanger 4, and a forward cycle defrosting operation mode in which the heat source-side heat exchanger 4 is defrosted by sequentially flowing refrigerant through the compressor 1, user-side heat exchanger 2, pressure reducing device 3, and heat source-side heat exchanger 4. In the heating operation mode, refrigerant is flowed through the refrigerant suction pipe 5f by the refrigerant flow path switching valve 8, and in the forward cycle defrosting operation mode, refrigerant is flowed through the heat exchange circuit 61 by the refrigerant flow path switching valve 8. This ensures that even in the forward cycle defrosting operation mode, the superheating of the refrigerant drawn into the compressor 1 is sufficiently maintained, preventing damage to the vanes 33 due to the load caused by liquid compression, preventing a decrease in the reliability of the compressor 1 due to liquid compression, and improving defrosting performance at low ambient temperatures.

[0050] Furthermore, in the refrigeration cycle device according to this embodiment, the heat storage tank 60 has a heat source other than the compressor 1, such as a heater, so that the amount of heating can be increased as needed in addition to the waste heat from the compressor 1, thereby ensuring a sufficient degree of superheating of the refrigerant drawn into the compressor 1.

[0051] Furthermore, in the refrigeration cycle device according to this embodiment, the heat exchange circuit 61 has an inner pipe through which the refrigerant passes, and by forming grooves or irregularities on at least one of the inner surface and outer surface of the inner pipe, the heat transfer coefficient can be improved, promoting heat exchange from the heat storage tank 60 to the refrigerant and ensuring a sufficient degree of superheating of the refrigerant drawn into the compressor 1.

[0052] Furthermore, the refrigeration cycle device according to this embodiment includes a detection unit 70 that detects the temperature of the suction refrigerant drawn into the compressor 1 or the temperature of the discharge refrigerant discharged from the compressor 1. In a heating operation mode in which the utilization-side heat exchanger 2 is used as a condenser by sequentially flowing refrigerant through the compressor 1, utilization-side heat exchanger 2, pressure reducing device 3, and heat source-side heat exchanger 4, if the degree of superheating estimated from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 is above a threshold, the refrigerant flow path switching valve 8 flows refrigerant through the refrigerant suction pipe 5f. If the degree of superheating is below the threshold, the refrigerant flow path switching valve 8 flows refrigerant through the heat exchange circuit 61. This ensures sufficient superheating of the refrigerant drawn into the compressor 1 when the degree of superheating is insufficient, such as at low ambient temperatures or when the compressor 1 is started up. This prevents damage to the vanes 33 due to the load caused by liquid compression and prevents a decrease in the reliability of the compressor 1 due to liquid compression.

[0053] Furthermore, the refrigeration cycle device according to this embodiment includes a detection unit 70 that detects the temperature of the suction refrigerant drawn into the compressor 1 or the temperature of the discharge refrigerant discharged from the compressor 1, and a control unit that estimates the degree of superheating from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 and switches the refrigerant flow path switching valve 8 according to the estimated degree of superheating. The control unit 80 switches the refrigerant flow path switching valve 8 so that refrigerant flows through the refrigerant suction pipe 5f if the estimated degree of superheating is above a threshold, and switches the refrigerant flow path switching valve 8 so that refrigerant flows through the heat exchange circuit 61 if the degree of superheating is below the threshold. This ensures that the degree of superheating of the refrigerant drawn into the compressor 1 is sufficient when the degree of superheating is insufficient, such as at low ambient temperatures or when the compressor 1 is started up, preventing damage to the vanes 33 due to the load caused by liquid compression and preventing a decrease in the reliability of the compressor 1 due to liquid compression.

[0054] Furthermore, in this embodiment, the refrigeration cycle device comprises a compressor 1 with an electric motor unit 20 and a compressor 1 structure 30 inside a sealed container 10, the electric motor unit 20 and the compression mechanism unit 30 connected by a shaft 40, the compression mechanism unit 30 having a cylinder 31, a piston 32 disposed inside the cylinder 31 and vanes 33 partitioning the inside of the cylinder 31, the shaft 40 having an eccentric portion 42, the cylinder 31 having a vane groove 36 for arranging the vanes 33, the eccentric portion 42 being disposed inside the cylinder 31, the piston 32 being fitted into the eccentric portion 42, the vanes 33 operating without separating from the piston 32, and the control unit 80 controlling the pressure reducing device 3 so that the degree of superheating is smaller when the rotational speed of the compressor 1 is in the low rotational speed range than when it is in the high rotational speed range.According to this embodiment, since the vanes 33 operate without separating from the piston 32, it is possible to prevent refrigerant leakage from the high-pressure side to the low-pressure side of the compression chamber 34. Furthermore, according to this embodiment, when the rotational speed of the compressor 1 is in the low rotational speed range, the amount of refrigerant circulated decreases, which reduces the amount of liquid return. As a result, liquid compression can be prevented even with a low degree of heating, and by reducing the degree of superheating, operation can be performed with high efficiency.

[0055] Furthermore, the refrigeration cycle device according to this embodiment includes a detection unit 70 that detects the temperature of the suction refrigerant drawn into the compressor 1 or the temperature of the discharge refrigerant discharged from the compressor 1. The control unit 80 estimates the degree of superheating from the suction refrigerant temperature or discharge refrigerant temperature detected by the detection unit 70 and controls the pressure reducing device 3 so that the degree of superheating falls within a preset target superheating range. By controlling the degree of superheating to fall within the target superheating range in this way, liquid compression can be prevented and highly efficient operation can be achieved.

[0056] Furthermore, in the refrigeration cycle device according to this embodiment, the target superheat range is set according to the rotational speed range of the compressor 1. By setting the target superheat range according to the rotational speed range of the compressor 1 in this way, liquid compression can be prevented and highly efficient operation can be achieved.

[0057] Furthermore, in this embodiment of the refrigeration cycle system, the degree of superheating is set to zero when the rotational speed of the compressor 1 is in the lowest rotational speed range. In this way, when the degree of superheating is zero, the refrigerant is in a wet state and liquid refrigerant is mixed in, but when the rotational speed of the compressor 1 is in the lowest rotational speed range, the load due to liquid compression is small and the vane 33 is not damaged, and because the compression ratio is reduced by setting the degree of superheating to zero, it can be operated at high efficiency.

[0058] Furthermore, in this embodiment, the refrigeration cycle device includes a compressor 1 comprising an electric motor unit 20 and a compression mechanism unit 30 within a sealed container 10, the electric motor unit 20 and the compression mechanism unit 30 connected by a shaft 40, the compression mechanism unit 30 having a cylinder 31, a piston 32 disposed within the cylinder 31, and vanes 33 partitioning the inside of the cylinder 31, the shaft 40 having an eccentric portion 42, the cylinder 31 having a vane groove 36 for arranging the vanes 33, the eccentric portion 42 being disposed within the cylinder 31, the piston 32 being fitted into the eccentric portion 42, the vanes 33 operating without separating from the piston 32, and the control unit 80 controlling the pressure reducing device 3 so that the high and low pressure difference of the refrigerant before and after the pressure reducing device 3 is smaller when the compressor 1 is rotating at a low speed than when it is rotating at a high speed.According to this embodiment, since the vanes 33 operate without separating from the piston 32, leakage of refrigerant from the high-pressure side to the low-pressure side of the compression chamber 34 can be prevented. Furthermore, according to this embodiment, when the rotational speed of the compressor 1 is in the low rotational speed range, the amount of refrigerant circulated decreases, which reduces the amount of liquid return. Therefore, liquid compression can be prevented even if the high and low pressure difference of the refrigerant before and after the pressure reducing device 3 is reduced, and operation can be performed with high efficiency by reducing the high and low pressure difference of the refrigerant before and after the pressure reducing device 3. In addition, according to this embodiment, when the rotational speed of the compressor 1 is in the low rotational speed range, the compression load can be reduced and the stability of the compressor rotation can be ensured by reducing the high and low pressure difference of the refrigerant before and after the pressure reducing device 3.

[0059] Furthermore, the refrigeration cycle system according to this embodiment includes a detection unit 70 that detects the high-pressure side temperature or high-pressure side pressure of the refrigerant upstream of the pressure reducing device 3, and the low-pressure side temperature or low-pressure side pressure of the refrigerant downstream of the pressure reducing device 3. The control unit 80 controls the pressure reducing device 3 so that the high-low pressure difference of the refrigerant detected by the detection unit 70 falls within a preset target high-low pressure difference range. By controlling the high-low pressure difference to fall within this target range, liquid compression can be prevented, highly efficient operation can be ensured, and the stability of the compressor rotation can be maintained.

[0060] Furthermore, in the refrigeration cycle device according to this embodiment, the target high and low pressure difference range is set according to the rotational speed range of the compressor 1. By setting the target high and low pressure difference range according to the rotational speed range of the compressor 1 in this way, it is possible to prevent liquid compression, ensure highly efficient operation, and guarantee stable compressor rotation.

[0061] Furthermore, in this embodiment, the refrigeration cycle device minimizes the high-low pressure difference when the compressor 1 is rotating at its lowest speed. In this way, the high-low pressure difference of the refrigerant before and after the pressure reducing device 3 becomes small, which may cause some liquid refrigerant to mix in. However, when the compressor 1 is rotating at its lowest speed, the load due to liquid compression is small, so the vane 33 will not be damaged. The low high-low pressure difference of the refrigerant allows for operation at high efficiency, and the stability of the compressor rotation can be ensured. [Industrial applicability]

[0062] The refrigeration cycle device of the present invention can be applied to hot water heating systems, air conditioning systems, water heaters, refrigerators, display cases, chillers, dehumidifiers, or refrigeration machines. [Explanation of Symbols]

[0063] 1. Compressor 2. Heat exchanger on the user side (condenser or evaporator) 3. Pressure reducing device 4. Heat source side heat exchanger (condenser or evaporator) 5 Refrigerant piping 5a Refrigerant discharge piping 5b First refrigerant piping 5c1 Second refrigerant piping (refrigerant piping connected to the heat exchanger side) 5c2 Third refrigerant piping (refrigerant piping connected to the pressure reducing device side) 5d Fourth refrigerant piping 5e Fifth Refrigerant Piping 5f Refrigerant intake piping 6 Receiver 7. Four-way valve 8. Refrigerant flow path switching valve 10 airtight containers 11 Oil reservoir 12 Suction pipe 13 Discharge pipe 14 Accumulator 14a Outer cylinder 14b Refrigerant suction pipe 14c Separation plate 14d Outer cylinder inlet 14e Suction pipe inlet 14f Liquid reservoir 20 Electric motor section 21 Stator 22 rotors 30 Compression mechanism 31 cylinders 32 pistons 32a Cylindrical groove 33 Bane 33a Side view of the vane 33b Cylindrical section 33c Waist area 34 Compression Chamber 34a Suction space 34b Compressed space 35 Suction passage 36 vane grooves 37 Discharge hole 40 shaft 41 Main shaft section 42 Eccentric part 43 Secondary shaft part 46. ​​Lubrication passage inside the shaft 47 Communication path 51 Upper bearing 52 Lower bearing 53 Top cover 54 Sound deadening room 60 Heat storage tank 61 Heat exchange circuit 70, 70a, 70b, 70c, 70d, 70e, 70f detection unit 80 Control Unit H Height

Claims

1. The compressor, the heat exchanger on the utilization side, the pressure reducing device, and the heat exchanger on the heat source side are connected in a ring by refrigerant piping. A refrigeration cycle system comprising a control unit that adjusts the amount of refrigerant circulated by controlling the rotational speed of the compressor and the throttle amount of the pressure reducing device, The compressor comprises an electric motor section and a compression mechanism section within a sealed container. The electric motor section and the compression mechanism section are connected by a shaft. The compression mechanism comprises a cylinder, a piston disposed within the cylinder, and vanes that partition the inside of the cylinder. The shaft has an eccentric portion, The cylinder has vane grooves formed in which the vanes are arranged. The eccentric portion is located inside the cylinder. The piston is fitted into the eccentric portion, The vane operates without separating from the piston, The control unit controls the pressure reducing device such that the degree of superheating is smaller when the compressor is rotating at a low speed than when it is rotating at a high speed. A refrigeration cycle device characterized by the following features.

2. The compressor is equipped with a detection unit for detecting the temperature of the suction refrigerant drawn into the compressor or the temperature of the discharge refrigerant discharged from the compressor. The control unit estimates the degree of superheating from the intake refrigerant temperature or the discharge refrigerant temperature detected by the detection unit, and controls the pressure reducing device so that the degree of superheating falls within a preset target range. The refrigeration cycle apparatus according to feature 1.

3. The target superheat range is set according to the rotational speed range of the compressor. The refrigeration cycle apparatus according to feature 2.

4. When the rotational speed of the compressor is in the lowest rotational speed range, the degree of superheating is set to zero. The refrigeration cycle apparatus according to feature 1.

5. The compressor, the heat exchanger on the utilization side, the pressure reducing device, and the heat exchanger on the heat source side are connected in a ring by refrigerant piping. A refrigeration cycle system comprising a control unit that adjusts the amount of refrigerant circulated by controlling the rotational speed of the compressor and the throttle amount of the pressure reducing device, The compressor comprises an electric motor section and a compression mechanism section within a sealed container. The electric motor section and the compression mechanism section are connected by a shaft. The compression mechanism comprises a cylinder, a piston disposed within the cylinder, and vanes that partition the inside of the cylinder. The shaft has an eccentric portion, The cylinder has vane grooves formed in which the vanes are arranged. The eccentric portion is located inside the cylinder. The piston is fitted into the eccentric portion, The vanes operate without separating from the piston, The control unit controls the pressure reducing device such that the pressure difference between the refrigerant before and after the pressure reducing device is smaller when the compressor is rotating at a low speed than when it is rotating at a high speed. A refrigeration cycle device characterized by the following features.

6. The device includes a detection unit that detects the high-pressure side temperature or high-pressure side pressure of the refrigerant upstream of the pressure reducing device, and the low-pressure side temperature or low-pressure side pressure of the refrigerant downstream of the pressure reducing device. The control unit controls the pressure reducing device so that the high / low pressure difference of the refrigerant detected by the detection unit falls within a preset target high / low pressure difference range. The refrigeration cycle apparatus according to feature 5.

7. The target high and low pressure difference range is set according to the rotational speed range of the compressor. The refrigeration cycle apparatus according to feature 6.

8. When the rotational speed of the compressor is in the lowest rotational speed range, the high-low pressure difference is minimized. The refrigeration cycle apparatus according to feature 5.

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