JPWO2019026270A1 - Refrigeration cycle device and heat source unit - Google Patents

Abstract

The refrigeration cycle device (2) is a refrigerant circulation in which a compressor (10), an oil separator (12), a condenser (14), an expansion valve (16), and an evaporator (18) are sequentially connected, and a refrigerant circulates. The circuit (20), a flow path for returning the refrigerant condensed in the condenser (14) to the compressor (10), and an injection flow path (50) provided with an on-off valve (54), and an injection flow path ( An oil return flow path (60) for joining the refrigerating machine oil separated by the oil separator (12) is provided upstream of the on-off valve (54) of 50).

Description

The present invention relates to a refrigeration cycle device including an oil return flow path for returning refrigerating machine oil separated by an oil separator to a compressor.

BACKGROUND ART Conventionally, there is known a refrigeration cycle device including an oil return flow path that returns refrigeration oil separated by an oil separator to a compressor (see, for example, Patent Document 1). In Patent Document 1, an opening/closing valve is provided in the oil return passage, and the refrigerating machine oil that has passed through the opening/closing valve returns to the compressor.

JP, 2007-178052, A

However, in Patent Document 1, since a high-temperature fluid in which the refrigerating machine oil and the gas refrigerant are mixed flows in the oil return flow path provided with the on-off valve, the on-off valve becomes hot and the operation of the on-off valve becomes unstable. May be In Patent Document 1, there is a risk that the compressor may malfunction due to poor oil return due to defective operation of the on-off valve.

The present invention has been made in view of the above problems, and an object thereof is to obtain a refrigeration cycle apparatus in which the risk of defective oil return is suppressed.

The refrigeration cycle device according to the present invention is configured such that a compressor, an oil separator, a condenser, an expansion valve, and an evaporator are sequentially connected, and a refrigerant circulation circuit in which a refrigerant circulates, and a refrigerant condensed in the condenser is supplied to the compressor. A flow path for returning, an injection flow path provided with an on-off valve, and an oil return flow path for joining the refrigerating machine oil separated by an oil separator upstream of the on-off valve of the injection flow path. is there.

In this invention, since the oil return flow passage is joined upstream of the on-off valve of the injection flow passage, the temperature of the fluid passing through the on-off valve is suppressed. According to the present invention, malfunctions due to high temperature of the on-off valve are suppressed, so that it is possible to obtain a refrigeration cycle device in which the risk of oil return failure is suppressed.

It is a figure which shows an example of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of a structure of the control apparatus described in FIG. It is a figure which shows an example of operation|movement of the refrigerating-cycle apparatus described in FIG. It is a figure which shows an example of the refrigerating-cycle apparatus which concerns on Embodiment 2 of this invention. It is the modification 1 of FIG. It is a figure which shows an example of the refrigerating-cycle apparatus which concerns on Embodiment 3 of this invention.

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals, and the description thereof will be appropriately omitted or simplified. Further, regarding the configuration shown in each drawing, the shape, size, arrangement, etc. can be appropriately changed within the scope of the present invention.

[Refrigeration cycle device]
Embodiment 1.
1 is a diagram showing an example of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. The refrigeration cycle apparatus 2 of the example of this embodiment is applied to a refrigeration apparatus that cools the inside of a warehouse or the like by utilizing a refrigeration cycle. The refrigeration cycle apparatus 2 has a refrigerant circulation circuit 20 formed by piping connection of the heat source unit 4 and the load unit 6.

[Refrigerant circulation circuit]
The refrigerant circulation circuit 20 is formed by sequentially connecting the compressor 10, the oil separator 12, the condenser 14, the expansion valve 16 and the evaporator 18 with piping, and circulates the refrigerant. The refrigerant applied to the refrigerant circulation circuit 20 of this embodiment is, for example, R410A, R32 or CO. _TwoA refrigerant having a low global warming potential (GWP), such as, but may be a mixed refrigerant containing at least one of them or another kind of refrigerant different from them. Further, the refrigeration cycle apparatus 2 of the example of this embodiment can use a non-azeotropic mixed refrigerant. The non-azeotropic mixed refrigerant is, for example, R407C or R448A. The non-azeotropic mixed refrigerant is R32, R125, R134a, R1234yf, CO_TwoOf the R32 ratio XR32 (wt %) of 33<XR32<39, the R125 ratio XR125 (wt %) of 27<XR125<33, and the R134a ratio of XR134a (wt). %) is 11<XR134a<17, a ratio of R1234yf XR1234yf (wt %) is 11<XR1234yf<17, and CO_TwoOf XCO_Two(Wt%) is 3<XCO_Two<9, XR32, XR125, XR134a, XR1234yf, XCO_TwoMay be a refrigerant that satisfies all of the condition that the sum of 100 is 100.

The compressor 10 compresses the sucked refrigerant, discharges the refrigerant in a high temperature and high pressure state. The compressor 10 is, for example, an inverter compressor controlled by an inverter, and the operating frequency can be arbitrarily changed to change the capacity (amount of refrigerant sent per unit time). The compressor 10 may be a constant speed compressor that operates at a constant operating frequency.

The oil separator 12 separates refrigerating machine oil from the high temperature and high pressure refrigerant discharged from the compressor 10. The refrigerating machine oil separated by the oil separator 12 is returned to the compressor 10 through the oil return passage 60. The condenser 14 condenses the refrigerant from which the refrigerating machine oil is separated by the oil separator 12. The condenser 14 has a refrigerant outflow portion through which the refrigerant flows out at a lower portion of the refrigerant inflow portion through which the refrigerant flows, and can efficiently exchange the refrigerant while exchanging heat with the refrigerant. The condenser 14 is, for example, a fin-tube heat exchanger formed by including a pipe through which the refrigerant flows and a fin through which the pipe is inserted. The condenser 14 may be a corrugated fin heat exchanger including pipes through which the refrigerant flows and corrugated fins that join the pipes together. The expansion valve 16 expands the refrigerant condensed in the condenser 14. The expansion valve 16 is formed of, for example, an electronic expansion valve whose opening can be adjusted, a thermal expansion valve, or the like, but may be formed of a capillary tube whose opening cannot be adjusted.

The evaporator 18 evaporates the refrigerant expanded by the expansion valve 16. The evaporator 18 is, for example, a fin-tube heat exchanger including a pipe through which a refrigerant flows and fins attached to the pipe.

[Load unit]
The load unit 6 supplies cold air to the cooling space inside the frozen warehouse. The load unit 6 is provided inside the frozen warehouse. The load unit 6 houses an expansion valve 16 and an evaporator 18 which are connected by piping. The load unit 6 also has a load side blower 19. When the load-side blower 19 operates, air is taken into the load unit 6 from the cooling space, the taken-in air passes through the evaporator 18, and the cold air that has passed through the evaporator 18 and has undergone heat exchange enters the cooling space. Blown out.

[Heat source unit]
The heat source unit 4 supplies cold heat to the load unit 6. The heat source unit 4 is installed outside the freezer warehouse. The heat source unit 4 may be installed in a machine room or the like outside the frozen warehouse. The heat source unit 4 accommodates the compressor 10, the oil separator 12, and the condenser 14 which are connected by piping. The heat source unit 4 also has a heat source side blower 15. By operating the heat source side blower 15, air is taken into the heat source unit 4, the taken air passes through the condenser 14, and the air that has undergone heat exchange through the condenser 14 is outside the heat source unit 4. Blown out. Further, the heat source unit 4 has an injection flow passage 50 and an oil return flow passage 60.

[Injection flow path]
The injection flow path 50 returns a part of the refrigerant condensed in the condenser 14 to the compressor 10. The injection flow path 50 is formed by a pipe that connects between the condenser 14 and the expansion valve 16 and an intermediate pressure compression chamber (not shown) of the compressor 10. The injection flow passage 50 may be a pipe connecting the condenser 14 and the expansion valve 16 to each other and a pipe connecting the low pressure side of the compressor 10. The injection flow path 50 is provided with an injection expansion valve 52 and an opening/closing valve 54. The injection expansion valve 52 expands the refrigerant flowing into the injection flow path 50. The injection expansion valve 52 is formed of, for example, an electronic expansion valve whose opening can be adjusted, a thermal expansion valve, or the like, but may be formed of a capillary tube whose opening cannot be adjusted.

The on-off valve 54 is provided downstream of the injection expansion valve 52. The opening/closing valve 54 controls the passage of fluid by opening/closing. The opening/closing valve 54 may be capable of freely adjusting the opening degree. When the on-off valve 54 is in the open state when the refrigeration cycle apparatus 2 is in operation and is in the closed state when the refrigeration cycle apparatus 2 is stopped, the on-off valve 54 may be provided away from the compressor 10. For example, the on-off valve 54 is provided closer to the confluence of the injection flow passage 50 and the oil return flow passage 60 than the compressor 10. By simply providing the opening/closing valve 54 away from the compressor 10, it is possible to prevent the opening/closing valve 54 from reaching a high temperature and further reduce the influence of vibration of the compressor 10. Therefore, malfunction and deterioration of the on-off valve 54 are suppressed. On the other hand, when the opening/closing valve 54 is to be opened/closed during the operation of the refrigeration cycle apparatus 2, the opening/closing valve 54 may be provided close to the compressor 10. For example, the opening/closing valve 54 is provided closer to the compressor 10 as compared with the junction of the injection flow passage 50 and the oil return flow passage 60. Since the on-off valve 54 is provided close to the compressor 10, the compression loss of the compressor 10 is reduced, so that high efficiency is realized.

[Oil return channel]
The oil return passage 60 joins the refrigeration oil separated by the oil separator 12 to the upstream side of the on-off valve 54 of the injection passage 50. The oil return passage 60 is formed by a pipe connecting the oil outlet of the oil separator 12 and a pipe between the injection expansion valve 52 and the opening/closing valve 54 of the injection passage 50.

The oil return passage 60 is provided with a capillary tube 62. The capillary tube 62 is for adjusting the flow rate of the fluid flowing through the oil return passage 60. A high-temperature fluid in which the gas refrigerant and the refrigerating machine oil are mixed flows through the oil return passage 60. Therefore, by forming the member provided in the oil return flow channel 60 with a static member such as the capillary tube 62, the fluid can be stably flown into the oil return flow channel 60. If the flow rate of the fluid flowing in the oil return passage 60 can be adjusted by adjusting the length, shape, flow passage cross-sectional area, etc. of the pipe forming the oil return passage 60, the capillary tube 62 can be used. Can be omitted.

In the example of this embodiment, the oil return passage 60 is connected to the injection passage 50 upstream of the on-off valve 54. Therefore, a mixed fluid of the fluid flowing in the injection flow passage 50 and the fluid flowing in the oil return flow passage 60 flows through the on-off valve 54. The temperature of the mixed fluid of the fluid flowing in the injection flow passage 50 and the fluid flowing in the oil return flow passage 60 is lower than the temperature of the fluid flowing in the oil return flow passage 60, so that the on-off valve 54 is prevented from reaching a high temperature. can do. Therefore, malfunction and deterioration of the on-off valve 54 due to high temperature are suppressed. Further, since the liquid refrigerant passes through the opening/closing valve 54, refrigerating machine oil, sludge, and the like attached to the opening/closing valve 54 are purified, so that the risk of malfunction of the opening/closing valve 54 is suppressed. Further, an injection expansion valve 52 is provided upstream of the opening/closing valve 54. The injection expansion valve 52 performs the opening/closing operation for adjusting the injection amount, so that the purification of the opening/closing valve 54 is promoted.

The heat source unit 4 also includes a discharge pressure sensor 22, a discharge temperature sensor 24, a suction pressure sensor 26, a suction temperature sensor 28, a control device 30, and a notification device 70. The discharge pressure sensor 22 detects the pressure of the refrigerant discharged from the compressor 10. The discharge temperature sensor 24 detects the temperature of the refrigerant discharged from the compressor 10. The suction pressure sensor 26 detects the pressure of the refrigerant sucked by the compressor 10. The suction temperature sensor 28 detects the temperature of the refrigerant sucked by the compressor 10. The control device 30 controls the refrigeration cycle device 2. The control device 30 is composed of, for example, a microcomputer. The control device 30 may be provided in the load unit 6, or may be provided in a remote controller or the like installed outside the heat source unit 4 and the load unit 6. The notification device 70 is to notify by sound, light, or the like. The notification device 70 may be a mobile terminal or the like that is provided outside the heat source unit 4 and that receives an instruction from the control device 30 to perform notification.

FIG. 2 is a diagram showing an example of the configuration of the control device shown in FIG. The control device 30 uses the detection results of the discharge pressure sensor 22, the discharge temperature sensor 24, the suction pressure sensor 26, the suction temperature sensor 28, and the like to compress the compressor 10, the heat source side blower 15, the expansion valve 16, the load side blower 19. , The injection expansion valve 52, the on-off valve 54, the notification device 70, and the like. Further, the control device 30 can control the refrigeration cycle device 2 by using the information stored in the storage unit 32. The storage unit 32 stores, for example, data in which processing procedures performed by the control device 30 are programmed.

[Refrigeration cycle operation]
Next, the operation of the refrigeration cycle will be described. As shown in FIG. 1, the refrigerant compressed by the compressor 10 is separated into refrigerating machine oil by the oil separator 12. The refrigerant from which the refrigerating machine oil is separated by the oil separator 12 is condensed by the condenser 14. The refrigerant condensed in the condenser 14 expands in the expansion valve 16. The refrigerant expanded by the expansion valve 16 is evaporated by the evaporator 18. The refrigerant evaporated in the evaporator 18 is sucked into the compressor 10 and compressed again.

The refrigerating machine oil separated from the refrigerant by the oil separator 12 passes through the oil return passage 60 and flows into the injection passage 50. The refrigerating machine oil that has flowed into the injection flow path 50 is returned to the compressor 10 through the on-off valve 54. That is, the refrigerating machine oil is returned to the compressor 10 when the open/close valve 54 is in the open state.

A part of the refrigerant condensed in the condenser 14 passes through the injection expansion valve 52 of the injection flow passage 50 and joins with the refrigerating machine oil flowing to the oil return flow passage 60. The refrigerant that has merged with the refrigerating machine oil flowing through the oil return passage 60 is returned to the compressor 10 through the on-off valve 54. That is, when the injection expansion valve 52 and the opening/closing valve 54 are in the open state, the injection into the compressor 10 is performed.

[Detection of abnormal oil return]
In the refrigeration cycle apparatus 2 of the example of this embodiment, the only element that can control passage of refrigerating machine oil is the on-off valve 54. Then, the refrigerant flowing in the injection flow passage 50 passes through the on-off valve 54 together with the refrigerating machine oil. Therefore, in the example of the present embodiment, when the refrigerant is flowing in the injection flow path 50, the discharge temperature T _d detected by the discharge temperature sensor 24 is used to cause the abnormality of the return oil due to the abnormality of the on-off valve 54. Can be detected. This is because when the oil return abnormality occurs due to the abnormality of the opening/closing valve 54, the flow of the refrigerant in the injection flow path 50 is blocked. For example, the control device 30 determines that there is a risk of oil return failure when the discharge temperature T _d detected by the discharge temperature sensor 24 is equal to or higher than a threshold value when flowing the refrigerant through the injection flow path 50, and a return process described below is performed. Executes oil abnormality processing.

The threshold value for determining the oil return abnormality is, for example, set in advance and stored in the storage unit 32. The preset threshold value is, for example, a value corresponding to the upper limit discharge temperature assumed during injection. Further, for example, the threshold value for determining the oil return abnormality is the reference discharge temperature T _dinj 0 of the compressor 10 when the injection is not performed. The reference discharge temperature T _dinj 0 can be calculated using the detection results of the discharge pressure sensor 22, the suction pressure sensor 26, and the suction temperature sensor 28. By setting the threshold value to the reference discharge temperature T _dinj 0, the oil return abnormality can be detected regardless of the load of the refrigeration cycle apparatus 2. The threshold value may be a value obtained by adding a positive set value to the reference discharge temperature T _dinj 0. By setting the value obtained by adding the set value from the reference discharge temperature T _dinj 0 as the threshold value, it is possible to reduce the risk of erroneous detection of oil return abnormality. Further, the threshold value may be a value in consideration of the amount of the refrigerant flowing in the injection flow channel 50. By increasing the accuracy of the threshold value, it is possible to accurately detect an abnormality of injection or oil return.

[Operation of refrigeration cycle device]
FIG. 3 is a diagram showing an example of the operation of the refrigeration cycle device shown in FIG. 1. In step S02 shown in FIG. 3, the refrigeration cycle apparatus 2 is performing a normal operation of cooling the cooling chamber. In step S04, if the refrigeration cycle device 2 is not performing the injection operation, the process returns to step S02, and if the refrigeration cycle device 2 is performing the injection operation, the process proceeds to step S06.

In step S06, the control unit 30 performs the discharge temperature T _d is determined whether at least a threshold, detecting the oil return abnormality when the discharge temperature T _d is above the threshold. The determination of the discharge temperature T _d in step S06 may be performed multiple times. By performing the determination of the discharge temperature T _d a plurality of times, it is possible to ensure the detection of the oil return abnormality and stabilize the operation of the refrigeration cycle apparatus 2. When the determination of the discharge temperature T _d is performed a plurality of times, the opening degree of the injection expansion valve 52 may be changed. By monitoring the change in the discharge temperature T _d when the opening degree of the injection expansion valve 52 is changed, it is possible to ensure the detection of the oil return abnormality, and also the injection expansion valve 52, the on-off valve 54, or another configuration. It can be predicted that an abnormality has occurred in the. The opening degree of the injection expansion valve 52 may be changed by increasing the opening degree. When the opening degree of the injection expansion valve 52 is increased, the discharge temperature T _d decreases. Therefore, the abnormality detection can be made reliable and the abnormality can be predicted only by comparing the discharge temperature T _d with the threshold value. As a result, the control of the control device 30 can be simplified. Further, by increasing the opening degree of the injection expansion valve 52, purification of the on-off valve 54 is promoted. This is because increasing the opening degree of the injection expansion valve 52 increases the amount of liquid refrigerant passing through the on-off valve 54. By cleaning the on-off valve 54, the abnormality of the on-off valve 54 is normalized, and the discharge temperature T _d becomes less than the threshold value, so that the normal operation can be continued. In step S06, when the discharge temperature T _d is lower than the threshold value, the process returns to step S02. In step S06, when the discharge temperature _Td is equal to or higher than the threshold value, the oil return abnormality process from step S08 is executed.

In step S08, the notification device 70 that has received the instruction from the control device 30 notifies that the oil return abnormality has occurred. The worker or the like who has received the notification can confirm the state of the refrigeration cycle apparatus 2 and eliminate the oil return abnormality by maintenance or the like. In the example of this embodiment, since there is a high possibility of oil return abnormality due to abnormality of the on-off valve 54, the operator may focus on the abnormality of the on-off valve 54.

In step S10, control device 30 reduces the rotation speed of compressor 10. The reduction in the rotation speed of the compressor 10 reduces the amount of refrigerating machine oil taken out from the compressor 10. Further, the reduction in the rotation speed of the compressor 10 suppresses the abrasion of the sliding portion and the like of the compressor 10. Therefore, it is possible to prevent the compressor 10 from being deteriorated or damaged. Furthermore, by continuing the operation of the refrigeration cycle apparatus 2 while reducing the rotational speed of the compressor 10 to operate it, it is possible to suppress the temperature rise of the cooling target.

In step S12, control device 30 changes the opening degree of injection expansion valve 52. By changing the opening degree of the injection expansion valve 52, the flow of the fluid passing through the on-off valve 54 changes, so that the purification of the on-off valve 54 is promoted. The opening degree of the injection expansion valve 52 may be changed in step S12 by increasing the opening degree. By increasing the opening degree of the injection expansion valve 52, the flow rate of the liquid refrigerant passing through the on-off valve 54 increases, and the purification of the on-off valve 54 is promoted.

In step S14, control device 30 opens and closes injection expansion valve 52. For example, when the opening degree of the injection expansion valve 52 is increased in step S12, the opening degree of the injection expansion valve 52 is decreased in step S14. When the opening degree of the injection expansion valve 52 is reduced in step S12, the opening degree of the injection expansion valve 52 is increased in step S14. By opening/closing the injection expansion valve 52, the flow of the fluid passing through the opening/closing valve 54 changes, so that purification of the opening/closing valve 54 is promoted. The opening/closing operation of the injection expansion valve 52 may be alternately executed a plurality of times. The pulsation of the refrigerant flowing through the injection flow path 50 further promotes the purification of the on-off valve 54.

In step S16, control device 30 causes opening/closing valve 54 to open/close. The opening/closing valve 54 may be opened/closed a plurality of times. By opening/closing the opening/closing valve 54, purification of the opening/closing valve 54 is promoted. By simultaneously executing the opening/closing operation of the injection expansion valve 52 and the opening/closing operation of the opening/closing valve 54, purification of the opening/closing valve 54 is further promoted.

In step S18, control device 30 determines whether discharge temperature T _d is equal to or higher than a threshold value. When the discharge temperature _Td is less than the threshold value, the control device 30 determines that the oil return abnormality has been resolved, and proceeds to step S24. In step S24, control device 30 stops the notification by notification device 70, ends the oil return abnormality process, and returns to step S02. When the discharge temperature T _d is equal to or higher than the threshold value in step S18 and the set time has elapsed in step S20, the process proceeds to step S22, and the compressor 10 is stopped. By stopping the compressor 10 when the time at which the discharge temperature T _d is equal to or higher than the threshold value becomes equal to or longer than the set time, it is possible to reduce the risk of failure of the compressor 10.

As described above, in the refrigeration cycle device 2 of the example of this embodiment, the compressor 10, the oil separator 12, the condenser 14, the expansion valve 16, and the evaporator 18 are sequentially connected, and the refrigerant circulation in which the refrigerant circulates. The circuit 20 is a flow path for returning the refrigerant condensed in the condenser 14 to the compressor 10, the injection flow path 50 provided with the open/close valve 54, and the oil separation upstream of the open/close valve 54 of the injection flow path 50. And an oil return passage 60 for joining the refrigerating machine oil separated in the container 12. In the example of this embodiment, the oil return passage 60 is joined upstream of the on-off valve 54 of the injection passage 50, so that the on-off valve 54 is prevented from reaching a high temperature. Further, in the example of this embodiment, the liquid refrigerant passes through the on-off valve 54, so that refrigerating machine oil, sludge, and the like attached to the on-off valve 54 are purified. Therefore, according to the example of the present embodiment, since the risk of malfunction of the on-off valve 54 is suppressed, the risk of oil return failure can be suppressed.

The refrigeration cycle apparatus 2 of the example of this embodiment has a compressor 10, an oil separator 12, and a condenser 14, and is a flow path for returning the refrigerant condensed in the condenser 14 to the compressor 10, A heat source unit including an injection flow passage 50 provided with an on-off valve 54, and an oil return flow passage 60 that joins the refrigerating machine oil separated by the oil separator 12 upstream of the on-off valve 54 of the injection flow passage 50. 4 can be formed.

For example, in the example of this embodiment, the oil return passage 60 is provided with the capillary tube 62. By forming the member provided in the oil return passage 60 through which the high temperature fluid flows by a static member such as the capillary tube 62, the fluid stably flows in the oil return passage 60. Therefore, according to the example of this embodiment, the risk of defective oil return can be suppressed.

Further, for example, in the example of this embodiment, since the injection flow passage 50 is connected to the intermediate pressure compression chamber of the compressor 10, a decrease in the amount of refrigerant sucked from the low pressure side of the compressor 10 is suppressed. ing. Therefore, according to the example of the present embodiment, the reduction of the operating capacity of the refrigeration cycle apparatus 2 is suppressed.

In addition, for example, in the example of this embodiment, the injection expansion valve 52 is provided upstream of the joining portion of the injection flow passage 50 and the oil return flow passage 60. For example, the injection expansion valve 52 is formed by a valve whose opening can be changed. By changing the opening of the injection expansion valve 52, purification of the on-off valve 54 is promoted.

Further, for example, in the example of this embodiment, the control device 30 executes the oil return abnormality process when the temperature detected by the discharge temperature sensor 24 becomes equal to or higher than the threshold value when the refrigerant is flowed through the injection flow passage 50. In the example of this embodiment, the only element that can control the passage of the refrigerating machine oil is the opening/closing valve 54, and the refrigerant flowing in the injection flow passage 50 passes through the opening/closing valve 54 together with the refrigerating machine oil. Therefore, according to the example of the present embodiment, the discharge temperature Td detected by the discharge temperature sensor 24 is used to detect the injection abnormality and the oil return abnormality due to the abnormality of the on-off valve 54, and the oil return abnormality processing is executed. be able to.

For example, the threshold value for determining the oil return abnormality is calculated from the reference discharge temperature T _dinj 0 obtained from the pressure detected by the suction pressure sensor 26, the temperature detected by the suction temperature sensor 28, and the pressure detected by the discharge pressure sensor 22. It By calculating the threshold value for determining the oil return abnormality from the reference discharge temperature T _dinj 0, the oil return abnormality can be detected regardless of the load of the refrigeration cycle apparatus 2. By setting the threshold value to the reference discharge temperature T _dinj 0 plus a set value having a positive value, it is possible to reduce the risk of erroneous detection of oil return abnormality.

Further, for example, in the example of this embodiment, the notification device 70 notifies that the oil return abnormality has occurred during the oil return abnormality processing. The worker or the like who has received the notification can confirm the state of the refrigeration cycle apparatus 2 and eliminate the oil return abnormality by maintenance or the like.

Further, for example, in the example of this embodiment, the rotation speed of the compressor 10 is reduced during the oil return abnormality processing. The reduction in the rotation speed of the compressor 10 reduces the amount of refrigerating machine oil taken out from the compressor 10. Further, by reducing the rotation speed of the compressor 10, wear of the sliding portion of the compressor 10 is suppressed. Therefore, according to the example of the present embodiment, it is possible to reduce the risk of the compressor 10 being deteriorated or damaged when there is a risk of oil return abnormality. Furthermore, the operation of the refrigeration cycle apparatus 2 can be continued while the compressor 10 is operating at a reduced rotation speed.

In addition, for example, in the example of this embodiment, the opening degree of the injection expansion valve 52 is changed during the oil return abnormality processing. By changing the opening degree of the injection expansion valve 52, the flow of the fluid passing through the on-off valve 54 changes, so that the purification of the on-off valve 54 is promoted. It should be noted that by increasing the opening degree of the injection expansion valve 52, the flow rate of the liquid refrigerant passing through the on-off valve 54 increases and the purification of the on-off valve 54 is promoted.

Further, for example, in the example of this embodiment, the injection expansion valve 52 is opened and closed during the oil return abnormality processing. By opening and closing the injection expansion valve 52, purification of the on-off valve 54 is promoted. By performing the opening/closing operation of the injection expansion valve 52 a plurality of times, pulsation occurs in the refrigerant flowing through the injection flow path 50, so that the purification of the opening/closing valve 54 is further promoted.

Further, for example, in the example of this embodiment, the opening/closing valve 54 is opened/closed during the oil return abnormality process. By opening/closing the opening/closing valve 54, purification of the opening/closing valve 54 is promoted. By simultaneously executing the opening/closing operation of the injection expansion valve 52 and the opening/closing operation of the opening/closing valve 54, purification of the opening/closing valve 54 is further promoted.

Note that this embodiment is not limited to the one described above.

For example, the operations of steps S08 to S16 can be performed in a different order. Furthermore, when the operation of step S18 is executed during the operation of steps S08 to S16 and the discharge temperature T _d becomes less than the threshold value, the notification by the notification device 70 is stopped and returned in step S24. It is also possible to terminate the oil abnormality processing and return to step S02.

In addition, for example, the operations of steps S04 to S24 can be executed when the refrigeration cycle apparatus 2 is installed, activated, or regularly inspected. The refrigeration cycle apparatus 2 can be stably operated by checking the operation of the on-off valve 54 and the like. For example, step S04 and step S06 are executed at preset timings, and when the discharge temperature T _d is equal to or higher than the threshold value in step S06, the processing of step S08 and subsequent steps is executed. Alternatively, in response to an instruction from an operator or the like, step S04 and step S06 are executed, and when the discharge temperature T _d is equal to or higher than the threshold value in step S06, the processing of step S08 and thereafter is executed. The operator uses an input unit (not shown) such as a switch provided in the refrigeration cycle apparatus 2 to give an instruction to perform the operation from step S04, for example.

Further, for example, the operations of steps S12 to S16 can be executed other than when the discharge temperature T _d is equal to or higher than the threshold value in step S06. For example, by performing the operations of steps S12 to S16 regularly or after receiving an instruction from an operator or the like, the cleaning of the on-off valve 54 is promoted, and therefore the return due to the malfunction of the on-off valve 54 is performed. The risk of oil failure is suppressed.

Further, for example, in the above description, an example in which the open state abnormality of the open/close valve 54 is detected has been described. However, according to this embodiment, the open state abnormality of the open/close valve 54 can also be detected. That is, an abnormality in the closed state of the on-off valve 54 can be detected by using the discharge temperature T _d when the injection expansion valve 52 is opened and the on-off valve 54 is closed.

Embodiment 2.
FIG. 4 is a diagram showing an example of a refrigeration cycle apparatus according to Embodiment 2 of the present invention. In FIG. 4, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted or simplified. As shown in FIG. 4, the heat source unit 4A of the refrigeration cycle apparatus 2A of the example of the present embodiment has a higher refrigerating machine oil cooling temperature than the heat source unit 4 of the refrigeration cycle apparatus 2 of the first embodiment shown in FIG. It has a container 141. The refrigerator oil cooler 141 cools the refrigerator oil separated by the oil separator 12. The refrigerating machine oil cooler 141 is provided, for example, in an air passage in which an air flow is formed by the operation of the heat source side blower 15, and causes the fluid flowing in the oil return passage 60 to exchange heat with the air. The refrigerator oil cooler 141 is provided below the condenser 14. The refrigerator oil cooler 141 has a smaller heat exchange area than the condenser 14. The refrigerator oil cooler 141 is formed to include, for example, a part of a pipe forming the oil return passage 60 and a fin attached to the part of the pipe. The condenser 14 and the refrigerator oil cooler 141 are integrally formed, for example, by being provided in different regions of a common fin, but they may be separately formed. The refrigerator oil cooler 141 is provided upstream of the capillary tube 62 in the oil return passage 60. The refrigerator oil cooler 141 may be provided downstream of the capillary tube 62 in the oil return passage 60.

The refrigerating machine oil separated by the oil separator 12 is cooled by the refrigerating machine oil cooler 141, passes through the capillary tube 62, and joins with the refrigerant flowing through the injection flow path 50. By cooling the fluid flowing through the oil return passage 60 by the refrigerator oil cooler 141, the heating of the refrigerant flowing through the injection passage 50 is suppressed, and the heating of the on-off valve 54 is suppressed. Further, since the heating of the refrigerant flowing through the injection flow passage 50 is suppressed, the flow rate of the refrigerant flowing through the injection flow passage 50 can be reduced. By reducing the flow rate of the refrigerant flowing through the injection flow path 50, the operation of the refrigeration cycle apparatus 2A can be made highly efficient.

A heat exchange inhibiting unit 142 is provided between the lower portion of the condenser 14 and the refrigerator oil cooler 141. The heat exchange blocker 142 suppresses the refrigerant flowing through the condenser 14 from being heated by the fluid flowing through the refrigerator oil cooler 141. In the example of this embodiment, a heat exchange inhibiting unit 142 is provided below the condenser 14. Since the condenser 14 has a configuration in which the refrigerant flows out from the lower portion, the heat of the refrigerant flowing to the condenser 14 is prevented by suppressing the heat exchange between the refrigerant after heat exchange and the refrigerating machine oil cooler 141. Can be suppressed. The heat exchange inhibition part 142 can be formed by, for example, making the distance between the condenser 14 and the refrigerating machine oil cooler 141 larger than the pitch of the pipe forming the condenser 14. The heat exchange inhibiting unit 151 may be formed of a heat insulating material or the like that inhibits heat exchange between the condenser 14 and the refrigerator oil cooler 141. In the example of this embodiment, since the heat exchange inhibiting unit 142 is provided, the heating of the refrigerant cooled by the condenser 14 is suppressed. As a result, the operation of the refrigeration cycle apparatus 2A can be made highly efficient.

As described above, the heat source unit 4A of the refrigeration cycle apparatus 2A according to the example of this embodiment has the refrigerator oil cooler 141 that cools the refrigerator oil separated by the oil separator 12. Therefore, according to this embodiment, heating of the on-off valve 54 is further suppressed. Furthermore, according to this embodiment, since the heating of the refrigerant flowing through the injection flow passage 50 is suppressed, the flow rate of the refrigerant flowing through the injection flow passage 50 is reduced, and the operation of the refrigeration cycle apparatus 2A is made highly efficient. You can

For example, the capillary tube 62 is provided in the oil return passage 60 downstream of the refrigerator oil cooler 141. By providing the capillary tube 62 downstream of the refrigerator oil cooler 141 in the oil return passage 60, it is possible to suppress heating of ambient air due to heat radiation from the pipe forming the capillary tube 62 and the oil return passage 60. ..

Further, for example, in the condenser 14, the refrigerant flows in from the upper portion and the refrigerant flows out from the lower portion, and the heat exchange inhibiting unit 142 that inhibits heat exchange between the lower portion of the condenser 14 and the refrigerating machine oil cooler 141 is provided. Has been. By providing the heat exchange inhibiting unit 142, it is possible to prevent the refrigerant cooled in the condenser 14 from being heated by the fluid flowing in the refrigerator oil cooler 141. As a result, the operation of the refrigeration cycle apparatus 2A can be made highly efficient.

[Modification 1]
Further, for example, FIG. 5 is a first modification of FIG. 4. The heat source unit 4B of the refrigeration cycle apparatus 2B of Modification 1 is provided with a refrigerating machine oil cooler 141A above the condenser 14 as compared with the heat source unit 4A of the refrigeration cycle apparatus 2A of FIG. Since the condenser 14 has a structure in which the refrigerant flows in from the upper part and the refrigerant flows out from the lower part, the refrigerating machine oil cooler 141A is provided in the upper part of the condenser 14 so that the refrigerant and the refrigerating machine oil after heat exchange are performed. It is possible to suppress heat exchange with the cooler 141A. That is, in the first modification, the heat exchange inhibition portion 142A is formed by the condenser 14 between the lower portion of the condenser 14 and the refrigerator oil cooler 141A. In the first modification, since the refrigerating machine oil cooler 141A, which has a high temperature, is provided above the condenser 14, the heat exchange in the condenser 14 is highly efficient. Further, since the heat exchange inhibition portion 142A is formed only by providing the refrigerator oil cooler 141A on the upper portion of the condenser 14, the structure can be simplified.

Embodiment 3.
FIG. 6 is a diagram showing an example of a refrigeration cycle apparatus according to Embodiment 3 of the present invention. In FIG. 6, the same components as those in FIG. 1 are designated by the same reference numerals, and the description will be omitted or simplified. As shown in FIG. 6, the heat source unit 4C of the refrigeration cycle apparatus 2C of the example of the present embodiment is different from the heat source unit 4 of the refrigeration cycle apparatus 2 of the first embodiment shown in FIG. 52 and the capillary tube 62 are omitted, and the opening/closing valve 54A is formed of an electronic expansion valve whose opening can be adjusted. In addition, when the flow rate of the refrigerant flowing in the injection flow passage 50 is adjusted by adjusting the length, shape, flow passage cross-sectional area, etc. of the pipe forming the injection flow passage 50, the on-off valve 54A, It can be switched between an open state and a closed state. According to the refrigeration cycle apparatus 2C of the example of the present embodiment, the number of constituent members is reduced as compared with the first embodiment, so that cost reduction can be realized.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention. That is, the configuration of the above-described embodiment may be appropriately improved, or at least a part of the configuration may be replaced with another configuration. Furthermore, the constituent elements that are not particularly limited in the arrangement are not limited to the arrangement disclosed in the embodiment, and can be arranged in a position where the function can be achieved.

For example, in the above-described first to third embodiments, the refrigeration cycle device applied to a large-scale refrigeration device that cools the inside of a refrigerating warehouse or the like has been described. It can be applied to small refrigerators. The refrigeration cycle apparatus can also be applied to an air conditioner that cools or heats the inside of a room, and a heating device that heats water and the like.

2 refrigeration cycle device, 2A refrigeration cycle device, 2B refrigeration cycle device, 2C refrigeration cycle device, 4 heat source unit, 4A heat source unit, 4B heat source unit, 4C heat source unit, 6 load unit, 10 compressor, 12 oil separator, 14 Condenser, 15
Heat source side blower, 16 expansion valve, 18 evaporator, 19 load side blower, 20 refrigerant circulation circuit, 22 discharge pressure sensor, 24 discharge temperature sensor, 26 suction pressure sensor, 28 suction temperature sensor, 30 control device, 32 storage unit, 50 injection flow passage, 52 injection expansion valve, 54 on-off valve, 54A on-off valve, 60 oil return flow passage, 62 capillary tube, 70 alarm device, 141 refrigerating machine oil cooler, 141A refrigerating machine oil cooler, 142 heat exchange inhibiting part, 142A Heat exchange inhibition part.

Claims (16)

A refrigerant circulation circuit in which a compressor, an oil separator, a condenser, an expansion valve, and an evaporator are sequentially connected, and a refrigerant circulates,
A flow path for returning the refrigerant condensed in the condenser to the compressor, and an injection flow path provided with an on-off valve,
Upstream of the on-off valve of the injection flow path, an oil return flow path for joining the refrigerating machine oil separated by the oil separator,
Refrigeration cycle device. A capillary tube is provided in the oil return channel,
The refrigeration cycle apparatus according to claim 1. A refrigerating machine oil cooler for cooling refrigerating machine oil is provided in the oil return passage,
The refrigeration cycle apparatus according to claim 1 or 2. The capillary tube is provided in the oil return channel downstream of the refrigerator oil cooler,
The refrigeration cycle apparatus according to claim 3, which refers to claim 2. The condenser is such that the refrigerant flows in from the upper part of the condenser and the refrigerant flows out from the lower part,
A heat exchange inhibition portion that inhibits heat exchange between the lower portion of the condenser and the refrigerator oil cooler is formed,
The refrigeration cycle apparatus according to claim 3 or 4. The injection flow path is connected to an intermediate pressure compression chamber of the compressor,
The refrigeration cycle apparatus according to any one of claims 1 to 5. An injection expansion valve is provided upstream of the confluent portion of the injection flow path with the oil return flow path,
The refrigeration cycle apparatus according to any one of claims 1 to 6. A discharge temperature sensor for detecting the temperature of the refrigerant discharged by the compressor,
When flowing the refrigerant in the injection flow path, when the temperature detected by the discharge temperature sensor is equal to or higher than a threshold value, a control device that executes an oil return abnormality process is further provided.
The refrigeration cycle apparatus according to any one of claims 1 to 7. A suction pressure sensor for detecting the pressure of the refrigerant sucked by the compressor;
A suction temperature sensor for detecting the temperature of the refrigerant sucked by the compressor,
A discharge pressure sensor for detecting the pressure of the refrigerant discharged from the compressor,
The control device calculates the threshold value from a reference discharge temperature obtained from a pressure detected by the suction pressure sensor, a temperature detected by the suction temperature sensor, and a pressure detected by the discharge pressure sensor,
The refrigeration cycle apparatus according to claim 8. Further comprising an informing device for informing,
At the time of the oil return abnormality processing, the control device causes the notification device to notify,
The refrigeration cycle apparatus according to claim 8 or 9. At the time of the oil return abnormality processing, the control device reduces the rotation speed of the compressor,
The refrigeration cycle apparatus according to any one of claims 8 to 10. At the time of the oil return abnormality processing, the control device changes the opening degree of the injection expansion valve,
The refrigeration cycle apparatus according to any one of claims 8 to 11, which cites claim 7. At the time of the oil return abnormality processing, the control device increases the opening degree of the injection expansion valve,
The refrigeration cycle apparatus according to claim 12. At the time of the oil return abnormality processing, the control device opens and closes the injection expansion valve,
The refrigeration cycle apparatus according to claim 12 or 13. At the time of the oil return abnormality processing, the control device opens and closes the on-off valve,
The refrigeration cycle apparatus according to any one of claims 8 to 14. It has a compressor, an oil separator, and a condenser,
A flow path for returning the refrigerant condensed in the condenser to the compressor, and an injection flow path provided with an on-off valve,
Upstream of the on-off valve of the injection flow path, an oil return flow path for joining the refrigerating machine oil separated by the oil separator,
Heat source unit.

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