JP6795680B2 - Refrigeration cycle equipment - Google Patents

Description

The present invention relates to a refrigeration cycle apparatus that defrosts the heat exchanger by switching the circulation direction of the refrigerant and causing the heat exchanger that has functioned as an evaporator in the heating mode to function as a condenser.

Conventionally, there is known a refrigeration cycle device that defrosts the heat exchanger by switching the circulation direction of the refrigerant and causing the heat exchanger, which has functioned as an evaporator in the heating mode, to function as a condenser. .. For example, Japanese Patent Application Laid-Open No. 2011-174662 (Patent Document 1) states that after performing a pump-down operation for recovering the refrigerant to a receiver, the refrigerant circuit is switched from a heating cycle to a cooling cycle by a four-way valve to start a defrost operation. Air heat source heat pump hot water supply / air conditioner is disclosed.

Japanese Unexamined Patent Publication No. 2011-174662

When the circulation direction of the refrigerant in the heating mode was switched by a flow path switching device such as a four-way valve in order to start the defrosting mode, it was connected to the discharge port of the compressor in the heating mode and functioned as a condenser. 1 A heat exchanger is connected to the suction port of the compressor. On the other hand, the second heat exchanger, which is connected to the suction port of the compressor in the heating mode and functions as an evaporator, is connected to the discharge port of the compressor in the defrost mode. In the heating mode, the pressure of the first heat exchanger connected to the discharge port (high pressure side) of the compressor is the pressure of the second heat exchanger connected to the suction port (low pressure side) of the compressor. Higher than pressure. Immediately after the refrigerant circulation direction is switched by the four-way valve to start the defrosting mode, the differential pressure in the heating mode remains between the first heat exchanger and the second heat exchanger. When the defrosting mode is started and the compressor is operated with the differential pressure remaining, a large amount of refrigerant can move from the first heat exchanger to the second heat exchanger.

When the amount of refrigerant remaining in the first heat exchanger decreases, the pressure and temperature of the first heat exchanger decrease. When the temperature of the first heat exchanger drops, for example, dew condensation in the refrigeration cycle device or heat exchange with the refrigerant in the first heat exchanger causes damage to the piping due to solidification of a heat medium such as water that transfers heat to the heating terminal. Can occur. As a result, stable operation of the refrigeration cycle apparatus may become difficult.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to suppress a temperature drop at the start of the defrosting mode in a heat exchanger that functions as a condenser in the heating mode. That is.

The refrigeration cycle apparatus according to the present invention includes a heating mode and a defrosting mode as operation modes. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger. In the defrost mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger. The refrigeration cycle device includes a flow control valve and a control device. The flow control valve is connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor. The control device controls the opening degree of the flow control valve. The control device switches the operation mode. The operation mode further includes a pressure equalizing mode. In the pressure equalization mode, the flow control valve is open. In the pressure equalization mode, the flow path resistance of the flow control valve corresponding to the opening degree of the flow control valve is larger than the flow path resistance of the flow control device. The control device switches the operation mode in the order of heating mode, pressure equalizing mode, and defrosting mode.

In the refrigeration cycle apparatus according to the present invention, when the operation mode is switched from the heating mode to the defrosting mode, the heating mode, the pressure equalizing mode, and the defrosting mode are executed in this order. In the pressure equalization mode, since the flow control valve is open, the refrigerant on the high pressure side moves to the low pressure side via the flow control valve. The differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side at the end of the pressure equalizing mode (at the start of the defrosting mode) is the difference at the start of the pressure equalizing mode (at the end of the heating mode). It becomes less than the pressure. Further, the flow path resistance corresponding to the opening degree of the flow control valve in the pressure equalizing mode is larger than the flow path resistance of the flow path switching device. Therefore, it is possible to suppress the amount of refrigerant flowing out from the first heat exchanger in the pressure equalizing mode. In the pressure equalization mode, the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side at the start of the defrosting mode is set to the end of the heating mode while suppressing the amount of refrigerant flowing out from the first heat exchanger. It can be made smaller than the differential pressure at the time. Further, the pressure equalizing mode is executed before the defrosting mode, and the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side at the start of the defrosting mode is changed to the differential pressure at the end of the heating mode. By making it smaller than, the amount of refrigerant flowing out from the first heat exchanger at the start of the defrosting mode can be suppressed. Therefore, it is possible to suppress the temperature drop of the first heat exchanger at the start of the defrosting mode. As a result, the refrigeration cycle device can be operated stably.

It is a figure which also shows the functional structure of the refrigerating cycle apparatus which concerns on Embodiment 1, and the flow of a refrigerant in a heating mode. It is a figure which also shows the functional structure of the refrigerating cycle apparatus of FIG. It is a flowchart for demonstrating the flow of the process performed by the control device of FIG. 1 when the defrost start condition is satisfied in a heating mode. It is a figure which also shows the functional structure of the refrigeration cycle apparatus of FIG. 1 and the flow of a refrigerant in a pressure equalizing mode. It is a flowchart which shows the flow of the process performed by the control device of FIG. 1 in a pressure equalizing mode. It is a flowchart which shows the flow of the process performed by the control device of FIG. 1 in the defrosting mode. FIG. 4 is an enlarged view of the vicinity of the connection portion between the flow path connecting the suction port of the compressor and the four-way valve in FIG. 4 and the flow path through which the refrigerant from the on-off valve passes. It is a figure which also shows the functional structure of the refrigerating cycle apparatus which concerns on Embodiment 2, and the flow of a refrigerant at the start of a defrosting mode. It is a flowchart which shows the flow of the process performed by the control device of FIG. 8 in a defrosting mode. It is a flowchart which shows the flow of the process performed by the control apparatus of the refrigeration cycle apparatus which concerns on Embodiment 3 when the defrost start condition is satisfied in a heating mode. It is a figure which also shows the functional structure of the refrigeration cycle apparatus which concerns on Embodiment 3 and the flow of the refrigerant in a pump down mode. It is a flowchart which shows the flow of the process performed by the control device of FIG. 11 in a pump down mode. It is a figure which also shows the functional structure of the refrigerating cycle apparatus which concerns on modification 1 of Embodiment 3 and the flow of a refrigerant in a pump down mode. It is a flowchart which shows an example of the process performed when the defrost start condition is satisfied in the refrigerating cycle apparatus which concerns on the modification 2 of Embodiment 3. It is a flowchart which shows another example of the process performed when the defrost start condition is satisfied in the refrigerating cycle apparatus which concerns on the modification 2 of Embodiment 3. It is a figure which also shows the functional structure of the refrigerating cycle apparatus which concerns on Embodiment 4, and the flow of a refrigerant in a pressure equalizing mode. It is a figure which also shows the functional structure of the refrigerating cycle apparatus which concerns on the modification of Embodiment 4, and the flow of a refrigerant in a pressure equalizing mode. It is a figure which also shows the functional structure of the refrigerating cycle apparatus which concerns on Embodiment 5, and the flow of a refrigerant in a pressure equalizing mode.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In principle, the same or corresponding parts in the drawings are designated by the same reference numerals and the description is not repeated.

Embodiment 1.
FIG. 1 is a diagram showing the functional configuration of the refrigeration cycle device 1 according to the first embodiment and the flow of the refrigerant in the heating mode. The operation mode of the refrigeration cycle device 1 includes a heating mode and a defrosting mode. As shown in FIG. 1, the refrigeration cycle device 1 includes a compressor 11, a heat exchanger 12, an expansion valve 13, a heat exchanger 14, a four-way valve 15, an on-off valve 16, and a control device 17. To be equipped. In the heating mode, the refrigerant circulates in the order of the compressor 11, the four-way valve 15, the heat exchanger 12, the expansion valve 13, and the heat exchanger 14. The on-off valve 16 corresponds to the flow control valve of the present invention.

The compressor 11 adiabatically compresses the low-pressure gas refrigerant (gas refrigerant) and discharges the high-pressure gas refrigerant.

In the heating mode, the four-way valve 15 connects the discharge port of the compressor 11 and the heat exchanger 12, and also connects the heat exchanger 14 and the suction port of the compressor 11. In the heating mode, the four-way valve 15 forms a flow path so that the refrigerant circulates in the order of the compressor 11, the four-way valve 15, the heat exchanger 12, the expansion valve 13, and the heat exchanger 14.

The heat exchanger 12 functions as a condenser in the heating mode. The gas refrigerant from the compressor 11 releases heat of condensation in the heat exchanger 12 and is condensed to become a liquid refrigerant (liquid refrigerant). In the heat exchanger 12, heat exchange is performed between the refrigerant and the heat medium that transfers heat to the heating terminal 100. Examples of the heat medium include water and brine (salt water).

The expansion valve 13 adiabatically expands the liquid refrigerant to reduce the pressure, and causes the liquid refrigerant to flow out as wet vapor in a gas-liquid two-phase state. As the expansion valve 13, for example, an electronically controlled expansion valve (LEV: Linear Expansion Valve) can be used.

The heat exchanger 14 is arranged outdoors and functions as an evaporator in the heating mode. The moist steam from the expansion valve 13 absorbs the heat of vaporization from the outside air in the heat exchanger 14 and vaporizes it.

The on-off valve 16 is connected in parallel with the compressor 11 between the discharge port and the suction port of the compressor 11. The flow path resistance of the on-off valve 16 is larger than the flow path resistance of the four-way valve 15. The flow path resistance of the on-off valve is the flow path resistance when the on-off valve is open (opening is fully open). That is, the Cv value of the on-off valve 16 when the on-off valve 16 is open is smaller than the Cv value of the four-way valve 15. The on-off valve 16 is closed in the heating mode.

The control device 17 switches the operation mode of the refrigeration cycle device 1. The control device 17 controls the drive frequency of the compressor 11 to control the amount of refrigerant discharged by the compressor 11 per unit time. The control device 17 controls the four-way valve 15 to switch the circulation direction of the refrigerant. The control device 17 controls the opening degree of the expansion valve 13. The control device 17 controls the opening and closing of the on-off valve 16. The control device 17 acquires the pressure of the refrigerant at the suction port of the compressor 11 (suction pressure) and the pressure of the refrigerant at the discharge port (discharge pressure) from the pressure sensors S1 and S2, respectively, and is the differential pressure between the discharge pressure and the suction pressure. Is calculated.

In the heating mode, frost may occur in the heat exchanger 14 which is arranged outdoors and functions as an evaporator. When frost is generated in the heat exchanger 14, the heat exchange efficiency of the heat exchanger 14 functioning as an evaporator is lowered, and the performance of the refrigeration cycle device 1 is lowered. In the refrigeration cycle apparatus 1, when frost is generated in the heat exchanger 14, the heating mode is interrupted and a defrosting mode is performed to remove the frost generated in the heat exchanger 14.

FIG. 2 is a diagram showing the functional configuration of the refrigeration cycle device 1 of FIG. 1 and the flow of the refrigerant in the defrosting mode. As shown in FIG. 2, in the defrosting mode, the four-way valve 15 connects the discharge port of the compressor 11 and the heat exchanger 14, and also connects the heat exchanger 12 and the suction port of the compressor 11. In the defrosting mode, the four-way valve 15 forms a flow path so that the refrigerant circulates in the order of the compressor 11, the four-way valve 15, the heat exchanger 14, the expansion valve 13, and the heat exchanger 12. The heat exchanger 14 functions as a condenser in the defrost mode. In the heat exchanger 14, the frost generated in the heat exchanger 14 is melted and removed by the heat of condensation released when the refrigerant is liquefied.

In the defrosting mode, the heat exchanger 12 connected to the high voltage side in the heating mode is connected to the low voltage side. On the other hand, the heat exchanger 14 connected to the low voltage side in the heating mode is connected to the high voltage side. In the heating mode, the pressure of the heat exchanger 12 connected to the high pressure side is higher than the pressure of the heat exchanger 14 connected to the low pressure side. Immediately after starting the defrosting mode, the differential pressure in the heating mode remains between the heat exchanger 12 and the heat exchanger 14. When the defrosting mode is started and the compressor 11 is operated with the differential pressure remaining, a large amount of refrigerant can move from the heat exchanger 12 to the heat exchanger 14.

When the amount of refrigerant remaining in the heat exchanger 12 decreases, the pressure and temperature of the heat exchanger 12 decrease. When the temperature of the heat exchanger 12 drops, for example, dew condensation in the refrigeration cycle device 1 or damage to the piping due to solidification of a heat medium such as water may occur. As a result, stable operation of the refrigeration cycle device 1 may become difficult.

Therefore, in the refrigeration cycle device 1, when the defrosting start condition is satisfied in the heating mode, the operation mode is switched in the order of the heating mode, the pressure equalizing mode, and the defrosting mode. In the pressure equalization mode, the connection state in the heating mode is maintained, the on-off valve 16 is opened, and the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side at the start of the defrosting mode is the heating mode. It is made smaller than the differential pressure at the end of. Since the flow path resistance of the on-off valve 16 is larger than the flow path resistance of the four-way valve 15, the amount of refrigerant flowing out of the heat exchanger 12 can be suppressed in the pressure equalization mode. In the pressure equalization mode, the differential pressure between the high pressure side pressure and the low pressure side pressure at the start of the defrosting mode is changed to the differential pressure at the end of the heating mode while suppressing the amount of refrigerant flowing out from the heat exchanger 12. Can be smaller than. Further, the pressure equalizing mode is executed before the defrosting mode, and the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side at the start of the defrosting mode is the differential pressure at the end of the heating mode. By making it smaller than the above, the amount of refrigerant flowing out from the heat exchanger 12 at the start of the defrosting mode can be suppressed. Therefore, it is possible to suppress the temperature drop of the heat exchanger 12 at the start of the defrosting mode. As a result, the refrigeration cycle device 1 can be operated stably.

FIG. 3 is a flowchart showing a flow of processing in which the control device 17 of FIG. 1 switches the operation mode of the refrigeration cycle device 1. In the following, the step is simply referred to as S. The process shown in FIG. 3 is performed by a main routine (not shown) that provides comprehensive control of the refrigeration cycle device 1.

As shown in FIG. 3, the control device 17 determines whether or not the termination condition of the refrigeration cycle device 1 is satisfied in S10. Examples of the end condition of the refrigeration cycle device 1 include a condition that the end operation is performed by the user or a condition that the end time set by the user has arrived. When the end condition is satisfied (YES in S10), the control device 17 returns the process to the main routine. If the end condition is not satisfied (NO in S10), the control device 17 advances the process to S20. The control device 17 executes the heating mode in S20. When the defrosting start condition is satisfied in the heating mode, the control device 17 advances the process to S200. Examples of the defrosting start condition include a condition that the temperature of the heat exchanger 14 is lower than the reference temperature, or a condition that the amount of frost generated in the heat exchanger 14 (frost formation amount) exceeds the reference amount. it can. The amount of frost formation can be calculated from the temperature of the heat exchanger 14 and the humidity around the heat exchanger 14.

After executing the pressure equalization mode in S200, the control device 17 advances the process to S300. The control device 17 returns the process to S10 after executing the defrosting mode in S300. The control device 17 switches the operation mode in the order of the heating mode (S20), the pressure equalizing mode (S200), and the defrosting mode (S300).

FIG. 4 is a diagram showing the functional configuration of the refrigeration cycle device 1 of FIG. 1 and the flow of the refrigerant in the pressure equalizing mode. As shown in FIG. 4, in the pressure equalizing mode, the control device 17 stops the compressor 11, closes the expansion valve 13, and opens the on-off valve 16. In the pressure equalizing mode, the four-way valve 15 maintains the connection between the discharge port of the compressor 11 and the heat exchanger 12 and the connection between the heat exchanger 14 and the suction port of the compressor 11 in the heating mode. Since the expansion valve 13 is closed, it is possible to prevent the refrigerant from moving from the heat exchanger 12 having a high refrigerant pressure to the heat exchanger 14 having a low refrigerant pressure via the expansion valve 13.

Since the on-off valve 16 is open, the refrigerant flows from the heat exchanger 12 to the heat exchanger 14 via the on-off valve 16. The flow path resistance of the on-off valve 16 is larger than the flow path resistance of the four-way valve 15. Therefore, the amount of refrigerant flowing out of the heat exchanger 12 in the pressure equalizing mode is smaller than the amount of refrigerant flowing out of the heat exchanger 12 when the defrosting mode is started without performing the pressure equalizing mode. In the pressure equalization mode, the differential pressure between the high pressure side pressure and the low pressure side pressure at the start of the defrosting mode is set from the differential pressure at the end of the heating mode while suppressing the amount of refrigerant flowing out from the heat exchanger 12. Can also be made smaller. As a result, the temperature drop of the heat exchanger 12 can be suppressed at the start of the defrosting mode performed after the pressure equalizing mode.

FIG. 5 is a flowchart showing a flow of processing performed by the control device 17 of FIG. 1 in the pressure equalizing mode. The process shown in FIG. 5 is the process performed in S200 of FIG.

As shown in FIG. 5, the control device 17 stops the compressor 11 in S201 and advances the process to S202. The control device 17 closes the expansion valve 13 in S202 and proceeds to the process in S203. The control device 17 opens the on-off valve 16 in S203 and proceeds to the process in S204. In S204, the control device 17 determines whether or not the differential pressure between the discharge pressure and the suction pressure is smaller than the reference differential pressure. When the differential pressure between the discharge pressure and the suction pressure is smaller than the reference differential pressure (YES in S204), the control device 17 has a sufficiently small differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side. Returns the process to the main routine. When the differential pressure between the discharge pressure and the suction pressure is equal to or higher than the reference differential pressure (NO in S204), the control device 17 advances the process to S205. The control device 17 determines whether or not the reference time has elapsed since the on-off valve 16 was opened in S205. When the reference time has elapsed since the on-off valve 16 was opened (YES in S205), the control device 17 considers that the pressure equalization between the high-pressure side refrigerant and the low-pressure side refrigerant is sufficiently performed, and performs the process. Return to the main routine. If the reference time has not elapsed since the on-off valve 16 was opened (NO in S205), the control device 17 waits for a certain period of time in S206 and then returns the process to S204. The reference differential pressure of S204 and the reference time of S205 can be appropriately calculated by an actual machine experiment or a simulation.

FIG. 6 is a flowchart showing a flow of processing performed by the control device 17 of FIG. 1 in the defrosting mode. The process shown in FIG. 6 is the process performed in S300 of FIG.

As shown in FIG. 6, the control device 17 switches the four-way valve 15 in S301 and advances the process to S302. The control device 17 closes the on-off valve 16 in S302 and proceeds to the process in S303. The control device 17 opens the expansion valve 13 to an appropriate opening degree in S303, and proceeds to the process in S304. The control device 17 starts the compressor 11 in S304 and advances the process to S305. The control device 17 determines whether or not the defrosting end condition is satisfied in S305. When the defrosting end condition is satisfied (YES in S305), the control device 17 returns the process to the main routine. When the defrosting end condition is not satisfied (NO in S305), the control device 17 waits for a certain period of time in S306 and then returns the process to S305. The defrosting end condition includes, for example, a condition that the temperature of the heat exchanger 14 is equal to or higher than the reference temperature, or a condition that the reference time has elapsed since the defrosting mode was started.

With reference to FIG. 4 again, in the refrigeration cycle apparatus 1, the height of the heat exchanger 12 is lower than the height of the four-way valve 15. Further, the height of the connecting portion J10 between the flow path connecting the suction port of the compressor 11 and the four-way valve 15 and the flow path through which the refrigerant from the on-off valve 16 passes is lower than the height of the four-way valve 15. Therefore, it becomes difficult for the refrigerant to move from the heat exchanger 12 to the four-way valve 15. Further, the refrigerant becomes difficult to move from the connecting portion J10 to the four-way valve 15. As a result, the amount of refrigerant flowing out of the heat exchanger 12 in the pressure equalization mode can be further suppressed.

FIG. 7 is an enlarged view of the vicinity of the connection portion J10 between the flow path RP1 connecting the suction port of the compressor 11 and the four-way valve 15 in FIG. 4 and the flow path RP2 through which the refrigerant from the on-off valve 16 passes. As shown in FIG. 7, in the refrigeration cycle apparatus 1, the angle α1 formed by the flow paths RP1 and RP2 is larger than 0 degrees and smaller than 180 degrees. Therefore, the refrigerant flowing through the flow path RP2 collides with the inner wall of the flow path RP1 at the connecting portion J10 between the flow path RP1 and the RP2. Since it becomes difficult for the refrigerant from the on-off valve 16 to join the flow path RP1, the amount of refrigerant per unit time passing through the on-off valve 16 in the pressure equalization mode is reduced. As a result, the amount of refrigerant flowing out of the heat exchanger 12 can be further suppressed in the pressure equalization mode.

Further, in the refrigeration cycle device 1, as shown in FIG. 7, the flow path RP2 is thinner than the flow path RP1. That is, the area of the refrigerant passing portion in the cross section of the flow path RP2 orthogonal to the traveling direction of the refrigerant moving in the flow path RP2 is the area of the refrigerant in the cross section of the flow path RP1 orthogonal to the traveling direction of the refrigerant moving in the flow path RP1. It is smaller than the area of the passing part. Compared with the case where the thickness of the flow path RP2 is the same as the thickness of the flow path RP1, the amount of refrigerant per unit time passing through the on-off valve 16 can be reduced in the pressure equalization mode. As a result, the amount of refrigerant flowing out of the heat exchanger 12 can be further suppressed. Further, the manufacturing cost of the refrigerating cycle apparatus 1 can be suppressed as compared with the case where the thickness of the flow path RP2 is the same as the thickness of the flow path RP1.

As described above, according to the refrigeration cycle apparatus according to the first embodiment, by executing the pressure equalizing mode before the defrosting mode, the heat exchanger functioning as a condenser in the heating mode is started in the defrosting mode. The temperature drop can be suppressed. As a result, the refrigeration cycle device can be operated stably.

Embodiment 2.
In the first embodiment, a case where the on-off valve opened in the pressure equalizing mode is closed before the compressor is started in the defrosting mode has been described. In the second embodiment, a case where the on-off valve is closed after starting the compressor in the defrosting mode will be described.

In the second embodiment, the compressor is operated with the on-off valve open for a while from the start of the defrosting mode. While the release valve is open, a part of the refrigerant discharged from the compressor is returned to the suction port of the compressor via the on-off valve. The amount of the refrigerant returned to the suction port of the compressor via the on-off valve makes it difficult for the refrigerant from the heat exchanger, which was functioning as a condenser in the heating mode, to be sucked into the compressor. As a result, the amount of refrigerant flowing out from the heat exchanger at the start of the defrosting mode can be further suppressed.

The difference between the second embodiment and the first embodiment is the flow of processing in the defrosting mode. The other points are the same as those in the first embodiment. That is, FIGS. 2 and 6 of the first embodiment are replaced with FIGS. 8 and 9 of the second embodiment, respectively. Since the configurations other than these are the same, the description will not be repeated.

FIG. 8 is a diagram showing the functional configuration of the refrigeration cycle device 2 according to the second embodiment and the flow of the refrigerant at the start of the defrosting mode. As shown in FIG. 8, the on-off valve 16 is open at the start of the defrosting mode of the refrigeration cycle device 2. While the on-off valve is open, a part of the refrigerant discharged from the compressor 11 is returned to the suction port of the compressor 11 via the on-off valve 16.

FIG. 9 is a flowchart showing a flow of processing performed by the control device 17 of FIG. 8 in the defrosting mode. As shown in FIG. 8, the control device 17 switches the four-way valve 15 in S311 and then proceeds to the process in S312. The control device 17 opens the expansion valve 13 to an appropriate opening degree in S312, and proceeds to the process in S313. The control device 17 activates the compressor 11 in S313 and advances the process to S314. The control device 17 determines whether or not the defrosting end condition is satisfied in S314. When the defrosting end condition is satisfied (YES in S314), the control device 17 advances the process to S315. The control device 17 determines whether or not the on-off valve 16 is open in S315. When the on-off valve 16 is closed (NO in S315), the control device 17 returns the process to the main routine. When the on-off valve 16 is open (YES in S315), the control device 17 returns the process to the main routine after closing the on-off valve 16 in S316.

If the defrosting end condition is not satisfied (NO in S314), the control device 17 advances the process to S317. In S317, the control device 17 determines whether or not the suction pressure exceeds the reference pressure. When the suction pressure exceeds the reference pressure (YES in S317), the control device 17 closes the on-off valve 16 in S319, waits for a certain period of time in S320, and then performs the process in S314, assuming that the suction pressure has risen sufficiently. Return to. When the suction pressure is equal to or lower than the reference pressure (NO in S317), the control device 17 advances the process to S318. The control device 17 determines whether or not the reference time has elapsed since the compressor 11 was started in S318. When the reference time has elapsed since the compressor 11 was started (YES in S318), the on-off valve 16 is closed in S319 and a fixed time in S320, assuming that a sufficient time has elapsed to increase the suction pressure. After waiting, the process returns to S314. If the reference time has not elapsed since the compressor 11 was started (NO in S318), the control device returns the process to S314. The reference pressure of S317 and the reference time of S318 can be appropriately calculated by an actual machine experiment or a simulation.

As described above, also in the refrigeration cycle apparatus according to the second embodiment, by executing the pressure equalizing mode before the defrosting mode, the temperature at the start of the defrosting mode of the heat exchanger functioning as a condenser in the heating mode. The decrease can be suppressed. As a result, the refrigeration cycle device can be operated stably.

In the second embodiment, the defrosting mode of the heat exchanger, which has functioned as a condenser in the heating mode, is started by operating the compressor with the on-off valve open for a while from the start of the defrosting mode. The temperature drop with time can be further suppressed. As a result, the refrigeration cycle device can be operated more stably.

Embodiment 3.
In the first embodiment, the case where the pressure equalization mode is performed after the heating mode when the defrosting start condition is satisfied has been described. In the third embodiment, when the defrosting start condition is satisfied, the pump down mode is performed after the heating mode, and the pressure equalizing mode is performed after the pump down mode. In the pump down mode, the amount of refrigerant in the heat exchanger, which was functioning as a condenser in the heating mode, is increased. By executing the pump down mode before the pressure equalizing mode, the amount of the refrigerant in the heat exchanger at the start of the pressure equalizing mode is increased as compared with the first embodiment. Therefore, the temperature drop at the start of the defrosting mode of the heat exchanger can be further suppressed. As a result, the refrigeration cycle device can be operated more stably.

The difference between the third embodiment and the first embodiment is that a pump down mode is added to the operation mode. That is, FIG. 3 of the first embodiment replaces FIG. 10 of the second embodiment. Other points are the same, so the explanation will not be repeated.

FIG. 10 is a flowchart showing a flow of processing in which the control device of the refrigeration cycle device according to the third embodiment switches the operation mode of the refrigeration cycle device. As shown in FIG. 10, when the defrosting start condition is satisfied in the heating mode (S20), the control device executes the pump down mode in S100. After that, the control device executes the pressure equalizing mode in S200 and the defrosting mode in S300 as in the first embodiment. When the defrosting start condition is satisfied, the control device switches the operation mode in the order of heating mode, pump down mode, pressure equalizing mode, and defrosting mode.

FIG. 11 is a diagram showing the functional configuration of the refrigeration cycle device 3 according to the third embodiment and the flow of the refrigerant in the pump down mode. As shown in FIG. 11, in the pump down mode, the control device 17 operates the compressor 11, closes the expansion valve 13, and closes the on-off valve 16. In the pump down mode, the four-way valve 15 maintains the connection between the discharge port of the compressor 11 and the heat exchanger 12 and the connection between the heat exchanger 14 and the suction port of the compressor 11. Since the expansion valve 13 is closed while the compressor 11 is operating, the refrigerant discharged from the compressor 11 is stored in the heat exchanger 12. While the pump down mode is in progress, the amount of refrigerant in the heat exchanger 12 increases. The amount of refrigerant in the heat exchanger 12 at the start of the pressure equalization mode is increased as compared with the first embodiment in which the pump down mode is not performed. At the start of the defrosting mode performed after the pressure equalization mode, the amount of refrigerant remaining in the heat exchanger 12 increases from the first embodiment, so that the temperature of the heat exchanger 12 is lowered from the first embodiment. Can also be suppressed.

FIG. 12 is a flowchart showing a flow of processing performed by the control device 17 of FIG. 11 in the pump down mode. The process shown in FIG. 12 is the process performed in S100 of FIG.

As shown in FIG. 12, the control device 17 closes the expansion valve 13 in S101 and proceeds to the process in S102. In S102, the control device 17 determines whether or not the suction pressure is smaller than the reference pressure. When the suction pressure is smaller than the reference pressure (YES in S102), the control device 17 assumes that the amount of refrigerant sucked into the compressor 11 has decreased due to the sufficient amount of refrigerant being stored in the heat exchanger 12. Returns the process to the main routine. When the suction pressure is equal to or higher than the reference pressure (NO in S102), the control device 17 advances the process to S103. The control device 17 determines whether or not the reference time has elapsed since the expansion valve 13 was closed in S103. When the reference time has elapsed since the expansion valve 13 was closed (YES in S103), the control device 17 considers that a sufficient time has elapsed to increase the amount of refrigerant in the heat exchanger 12, and performs the process. Return to the main routine. If the reference time has not elapsed since the expansion valve 13 was closed (NO in S103), the control device 17 waits for a certain period of time in S104 and then returns the process to S102.

Modification example of the third embodiment 1.
It is assumed that the amount of refrigerant flowing into the heat exchanger 12 in the pump down mode exceeds the capacity of the heat exchanger 12. In preparation for such a case, it is desirable that the refrigerant reservoir 30 is connected between the heat exchanger 12 and the expansion valve 13 as in the refrigeration cycle device 3A shown in FIG. When the amount of refrigerant flowing into the heat exchanger 12 exceeds the capacity of the heat exchanger 12, the refrigerant flowing out of the heat exchanger 12 is stored in the refrigerant reservoir 30. Therefore, the amount of the refrigerant existing on the high pressure side at the end of the pump down mode can be increased as compared with the third embodiment. As a result, the temperature drop at the start of the defrosting mode of the heat exchanger 12 can be further suppressed.

Modification example of the third embodiment 2.
The greater the amount of frost (frost formation) generated in the heat exchanger that was functioning as an evaporator in the heating mode, the greater the heat capacity of the heat exchanger in the defrost mode. The larger the heat capacity of the heat exchanger to be defrosted, the larger the amount of refrigerant flowing into the heat exchanger at the start of the defrost mode. Therefore, as the amount of frost formation increases, the amount of refrigerant flowing out from the heat exchanger functioning as a condenser in the heating mode at the start of the defrosting mode increases. On the contrary, when the amount of frost formation is small, the amount of refrigerant flowing out from the heat exchanger functioning as a condenser in the heating mode at the start of the defrosting mode decreases. When the amount of frost formation is small, it is desirable to shorten the time during which the pump down mode is performed in order to shorten the interruption time of the heating mode. For example, when the amount of frost formation is smaller than the reference amount (YES in S30) as in the process shown in FIG. 14, the reference time in S103 in FIG. 12 may be shortened by a predetermined ratio (S40). By performing the process as shown in FIG. 14, the time during which the pump down mode (S200) is performed can be shortened. Since the time from the establishment of the defrosting start condition to the end of the defrosting mode can be shortened, the interruption time of the heating mode can be shortened.

Alternatively, it may be determined whether or not to perform the pump down mode according to the amount of frost formation. For example, when the amount of frost formation is smaller than the reference amount (YES in S30) as in the process shown in FIG. 15, the pressure equalization mode (S200) may be executed without performing the pump down mode. By performing the process as shown in FIG. 15, an unnecessary pump down mode can be avoided. As a result, the interruption time of the heating mode can be shortened.

As described above, even in the refrigeration cycle apparatus according to the third embodiment, the first modification, and the second modification, the pressure equalizing mode is executed before the defrost mode, so that the condenser can be used as a condenser in the heating mode at the start of the defrost mode. It is possible to suppress the temperature drop of the heat exchanger that was functioning. As a result, the refrigeration cycle device can be operated stably.

In the refrigeration cycle apparatus according to the third embodiment, the first modification, and the second modification, the pump down mode is performed before the pressure equalization mode, so that the inside of the heat exchanger functioning as a condenser in the heating mode. The pressure equalization mode is executed after increasing the amount of refrigerant. Therefore, the temperature drop at the start of the defrosting mode of the heat exchanger can be further suppressed. As a result, the refrigeration cycle device can be operated more stably.

Embodiment 4.
Some flow path switching devices such as four-way valves cannot switch the connection state of the refrigeration cycle device unless the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side is equal to or higher than the reference differential pressure. is there. In the fourth embodiment, a case where the differential pressure is maintained at a reference differential pressure or higher will be described in order to guarantee the operation of the flow path switching device.

The difference between the fourth embodiment and the first embodiment is that in the fourth embodiment, the four-way valve is used when the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side is equal to or higher than the reference differential pressure. It is operable and is equipped with a constant differential pressure valve that keeps the differential pressure above the reference differential pressure. Since the other configurations are the same, the description will not be repeated.

FIG. 16 is a diagram showing the functional configuration of the refrigeration cycle device 4 according to the fourth embodiment and the flow of the refrigerant in the pressure equalizing mode. As shown in FIG. 16, in the refrigeration cycle device 4, the four-way valve 15 of the refrigeration cycle device 1 shown in FIG. 4 is replaced with the four-way valve 154. The four-way valve 154 can operate when the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side is equal to or higher than the reference differential pressure. Further, the refrigeration cycle device 4 further includes a constant differential pressure valve 40 in addition to the configuration of the refrigeration cycle device 1 shown in FIG. The constant differential pressure valve 40 is connected in series with the on-off valve 16 between the discharge port and the suction port of the compressor 11. The constant differential pressure valve 40 is a mechanical valve that keeps the pressure difference at both ends of the constant differential pressure valve 40 equal to or higher than the reference differential pressure.

In the refrigeration cycle device 4, the constant differential pressure valve 40 maintains the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side to be equal to or higher than the reference differential pressure. Therefore, it is possible to prevent the occurrence of a situation in which the four-way valve 154 does not operate because the differential pressure is smaller than the reference differential pressure.

A modified example of the fourth embodiment.
The configuration in which the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side can be equal to or higher than the reference differential pressure is not limited to the constant differential pressure valve. For example, as in the refrigeration cycle device 4A shown in FIG. 17, a valve 41 capable of stepwise adjusting the opening degree in the open state is used instead of the on-off valve 16, and the pressure of the refrigerant on the high pressure side and the refrigerant on the low pressure side are used. The opening degree of the valve 41 may be adjusted by the control device 17 so that the differential pressure from the pressure of the above pressure becomes equal to or higher than the reference differential pressure.

As described above, even in the refrigeration cycle apparatus according to the fourth embodiment and the modified example, the heat exchange functioning as a condenser in the heating mode at the start of the defrost mode by executing the pressure equalizing mode before the defrost mode. It is possible to suppress the temperature drop of the vessel. As a result, the refrigeration cycle device can be operated stably.

According to the refrigeration cycle device according to the fourth embodiment and the modified example, the flow path switching device operates when the differential pressure between the pressure of the refrigerant on the high pressure side and the pressure of the refrigerant on the low pressure side is smaller than the reference differential pressure. It is possible to prevent the occurrence of a situation in which it cannot be done. As a result, the refrigeration cycle device can be operated more stably.

Embodiment 5.
In the fifth embodiment, a case where a gas-liquid separator is connected between the on-off valve and the suction port of the compressor will be described. The refrigerant flowing out from the heat exchanger functioning as a condenser in the heating mode in the pressure equalization mode is stored in the gas-liquid separator in the pressure equalization mode. At the start of the defrost mode, in addition to the refrigerant from the heat exchanger that functioned as a condenser in the heating mode, the refrigerant from the gas-liquid separator is also added, so that the refrigerant flows out from the heat exchanger at the start of the defrost mode. The amount of the refrigerant to be used can be suppressed as compared with the first embodiment.

Further, even when the flow path resistance of the on-off valve is made smaller than that of the first embodiment and the amount of refrigerant flowing out from the heat exchanger functioning as the condenser in the heating mode is increased, the heat exchanger is in the pressure equalizing mode. Refrigerant from is stored in the gas-liquid separator. Since the refrigerant from the gas-liquid separator is added to the refrigerant sucked into the compressor at the start of the defrost mode, the temperature of the heat exchanger functioning as the condenser in the heating mode is reduced to the same level as in the first embodiment. It can be suppressed. The time required for the pressure equalization mode can be shortened as compared with the first embodiment by making the flow path resistance of the on-off valve smaller than that of the first embodiment. As a result, the interruption time of the heating operation can be shortened.

FIG. 18 is a diagram showing the functional configuration of the refrigeration cycle device 5 according to the fifth embodiment and the flow of the refrigerant in the pressure equalizing mode. As shown in FIG. 18, in the refrigeration cycle device 5, the on-off valve 16 of the refrigeration cycle device 1 shown in FIG. 4 is replaced with the on-off valve 165. Flow resistance of the on-off valve 165 in a state where the opening and closing valve 165 is open, larger than the flow path resistance of the four-way valve 15, the on-off valve 165 is smaller than the flow path resistance of the on-off valve 165 in a state of open. Further, the refrigeration cycle apparatus 5 further includes a gas-liquid separator 50 in addition to the configuration of the refrigeration cycle apparatus 1 shown in FIG. The gas-liquid separator 50 is connected between the on-off valve 165 and the suction port of the compressor 11. The gas-liquid separator 50 includes a discharge port LS1 that discharges the stored liquid refrigerant. The discharge port LS1 is connected to the confluence point J2 of the flow path connecting the suction port of the compressor 11 and the four-way valve 15. The height of the discharge port LS1 is lower than the height of the confluence J2.

The refrigerant flowing out of the heat exchanger 12 in the pressure equalization mode passes through the on-off valve 165 and is then stored in the gas-liquid separator 50. The liquid refrigerant stored in the gas-liquid separator 50 is discharged from the discharge port LS1 and joins the refrigerant heading for the heat exchanger 14 at the confluence point J2.

In the pressure equalization mode, the refrigerant from the heat exchanger 12 passes through the on-off valve 165 and is then stored in the gas-liquid separator 50. Since the refrigerant from the gas-liquid separator 50 is added in addition to the refrigerant from the heat exchanger 12 at the start of the defrost mode, the amount of the refrigerant flowing out from the heat exchanger 12 at the start of the defrost mode should be suppressed. Can be done. Further, since the flow path resistance of the on-off valve 165 is smaller than that of the on-off valve 165 of the first embodiment, the time required for the pressure equalization mode can be shortened as compared with the first embodiment. Further, since the height of the discharge port LS1 is lower than the height of the confluence point J2, the amount of refrigerant discharged from the gas-liquid separator 50 can be suppressed. As a result, the amount of refrigerant moving from the high pressure side to the low pressure side can be further suppressed.

As described above, also in the refrigeration cycle apparatus according to the fifth embodiment, by executing the pressure equalizing mode before the defrosting mode, the temperature at the start of the defrosting mode of the heat exchanger functioning as a condenser in the heating mode. The decrease can be suppressed. As a result, the refrigeration cycle device can be operated stably.

According to the refrigeration cycle apparatus according to the fifth embodiment, the refrigerant from the heat exchanger, which was functioning as a condenser in the heating mode, is stored in the gas-liquid separator to function as a condenser in the heating mode. The amount of refrigerant flowing out from the heat exchanger at the start of the defrosting mode can be suppressed. Further, since the flow path resistance of the on-off valve can be made smaller than that of the first embodiment, the time required for the pressure equalization mode can be made smaller than that of the first embodiment.

It is also planned that the embodiments disclosed this time will be appropriately combined and implemented within a consistent range. It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims.

1,2,3A, 4,4A, 5 Refrigeration cycle device, 11 Compressor, 12,14 Heat exchanger, 13 Expansion valve, 15,154 Four-way valve, 16,165 On-off valve, 17 Control device, 30 Refrigerant reservoir , 40 constant differential pressure valve, 41 valve, 50 gas-liquid separator, 100 heating terminal, LS1 discharge port, RP1, RP2 flow path, S1, S2 pressure sensor.

Claims (15)

The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
A control device configured to control the opening degree of the flow control valve and switch the operation mode, and
E Bei a connected gas-liquid separator between the flow regulating valve and the suction port,
The operation mode further includes a pressure equalizing mode.
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The control device is configured to switch the operation mode in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
The gas-liquid separator includes a liquid discharge port that discharges the stored liquid of the refrigerant.
The liquid discharge port, the is connected to a channel connecting the suction port and with said flow switching device, refrigerating cycle apparatus. The flow path switching device is configured to switch the connection state of the refrigeration cycle device between the first connection state and the second connection state.
The control device
In the heating mode, the connection state is set to the first connection state, the compressor is operated, the expansion valve is opened, the flow control valve is closed, and the flow control valve is closed.
In the pressure equalization mode, the connection state is maintained in the first connection state, the compressor is stopped, the expansion valve is closed, and the opening degree is increased.
The defrosting mode is configured to set the connection state to the second connection state, operate the compressor, open the expansion valve, and close the flow control valve. The refrigeration cycle apparatus according to 1. The refrigeration cycle device according to claim 2, wherein the control device is configured to close the flow control valve before starting the compressor in the defrost mode. The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
It is provided with a control device configured to control the opening degree of the flow control valve and switch the operation mode.
The operation mode further includes a pressure equalizing mode.
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The control device is configured to switch the operation mode in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
The flow path switching device is configured to switch the connection state of the refrigeration cycle device between the first connection state and the second connection state.
The control device is
In the heating mode, the connection state is set to the first connection state, the compressor is operated, the expansion valve is opened, the flow control valve is closed, and the flow control valve is closed.
In the pressure equalization mode, the connection state is maintained in the first connection state, the compressor is stopped, the expansion valve is closed, and the opening degree is increased.
In the defrosting mode, the connection state is set to the second connection state, the compressor is operated, the expansion valve is opened, and the flow control valve is closed.
The control device, the vibration in the frost mode, the after starting the compressor being configured to close the flow regulating valve, refrigerating cycle apparatus. The operating mode further includes a pump down mode that increases the amount of the refrigerant in the first heat exchanger.
The control device switches the operation mode in the order of the heating mode, the pump down mode, the pressure equalizing mode, and the defrosting mode.
The pump down mode is configured to maintain the connection state in the first connection state, operate the compressor, close the expansion valve, and close the flow control valve. 2. The refrigeration cycle apparatus according to any one of claims 4. The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
It is provided with a control device configured to control the opening degree of the flow control valve and switch the operation mode.
The operation mode may further include a pressure equalization mode, and a pump-down mode to increase the amount of the refrigerant in said first heat exchanger,
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The flow path switching device is configured to switch the connection state of the refrigeration cycle device between the first connection state and the second connection state.
The control device is
In the heating mode, the connection state is set to the first connection state, the compressor is operated, the expansion valve is opened, the flow control valve is closed, and the flow control valve is closed.
In the pressure equalization mode, the connection state is maintained in the first connection state, the compressor is stopped, the expansion valve is closed, and the opening degree is increased.
In the defrosting mode, the connection state is set to the second connection state, the compressor is operated, the expansion valve is opened, and the flow control valve is closed.
The control device switches the operation mode in the order of the heating mode, the pump down mode, the pressure equalizing mode, and the defrosting mode.
In the pump down mode, the connection state is maintained in the first connection state, the compressor is operated, the expansion valve is closed, and the flow control valve is closed.
Wherein the control device, in response to said frost amount of the second heat exchanger in the heating mode, the is configured to adjust the operating time of the pump-down mode, refrigeration cycle apparatus. The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
It is provided with a control device configured to control the opening degree of the flow control valve and switch the operation mode.
The operation mode may further include a pressure equalization mode, and a pump-down mode to increase the amount of the refrigerant in said first heat exchanger,
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The control device is configured to switch the operation mode in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
The flow path switching device is configured to switch the connection state of the refrigeration cycle device between the first connection state and the second connection state.
The control device is
In the heating mode, the connection state is set to the first connection state, the compressor is operated, the expansion valve is opened, the flow control valve is closed, and the flow control valve is closed.
In the pressure equalization mode, the connection state is maintained in the first connection state, the compressor is stopped, the expansion valve is closed, and the opening degree is increased.
In the defrosting mode, the connection state is set to the second connection state, the compressor is operated, the expansion valve is opened, and the flow control valve is closed.
The control device
When the amount of frost formed on the second heat exchanger in the heating mode is larger than the reference amount, the operation mode is switched in the order of the heating mode, the pump down mode, the pressure equalizing mode, and the defrosting mode.
When the amount of frost formation in the heating mode is smaller than the reference amount, the operation mode is switched in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
In the pump-down mode, maintaining the connection state to the first connection state, is operated the compressor, closing the said expansion valve is configured to close the flow regulating valve, Frozen Cycle device. The refrigeration cycle apparatus according to any one of claims 5 to 7, further comprising a refrigerant storage unit connected between the first heat exchanger and the expansion valve. The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
It is provided with a control device configured to control the opening degree of the flow control valve and switch the operation mode.
The operation mode further includes a pressure equalizing mode.
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The control device is configured to switch the operation mode in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
The flow path switching device is configured to switch the connection state of the refrigeration cycle device between the first connection state and the second connection state.
The control device is
In the heating mode, the connection state is set to the first connection state, the compressor is operated, the expansion valve is opened, the flow control valve is closed, and the flow control valve is closed.
In the pressure equalization mode, the connection state is maintained in the first connection state, the compressor is stopped, the expansion valve is closed, and the opening degree is increased.
In the defrosting mode, the connection state is set to the second connection state, the compressor is operated, the expansion valve is opened, and the flow control valve is closed.
The flow path switching device is connected when the pressure difference between the pressure of the refrigerant from the discharge port to the expansion valve and the pressure of the refrigerant from the expansion valve to the suction port is equal to or more than a reference differential pressure. It is possible to switch the state,
The refrigeration cycle apparatus further includes a constant differential pressure valve connected in series with the flow control valve between the discharge port and the suction port.
The constant differential pressure valve maintains the differential pressure in the reference difference on pressure or, refrigerating cycle apparatus. The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
It is provided with a control device configured to control the opening degree of the flow control valve and switch the operation mode.
The operation mode further includes a pressure equalizing mode.
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The control device is configured to switch the operation mode in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
The flow path switching device is configured to switch the connection state of the refrigeration cycle device between the first connection state and the second connection state.
The control device is
In the heating mode, the connection state is set to the first connection state, the compressor is operated, the expansion valve is opened, the flow control valve is closed, and the flow control valve is closed.
In the pressure equalization mode, the connection state is maintained in the first connection state, the compressor is stopped, the expansion valve is closed, and the opening degree is increased.
In the defrosting mode, the connection state is set to the second connection state, the compressor is operated, the expansion valve is opened, and the flow control valve is closed.
The flow path switching device is connected when the pressure difference between the pressure of the refrigerant from the discharge port to the expansion valve and the pressure of the refrigerant from the expansion valve to the suction port is equal to or more than a reference differential pressure. It is possible to switch the state,
It said control device, wherein the pressure equalization mode, the differential pressure is configured to adjust the opening so that the reference difference on pressure or, refrigerating cycle apparatus. The height of the liquid discharge port, wherein said liquid from the liquid discharge port lower than the height of the confluence merging into the flow path, the refrigeration cycle apparatus according to claim 1. The operation mode includes a heating mode and a defrosting mode. In the heating mode, the refrigerant circulates in the order of the compressor, the flow path switching device, the first heat exchanger, the expansion valve, and the second heat exchanger, and the defrosting is performed. In the mode, the refrigerant is a refrigeration cycle device in which the compressor circulates in the order of the compressor, the flow path switching device, the second heat exchanger, the expansion valve, and the first heat exchanger.
A flow control valve connected in parallel with the compressor between the discharge port of the compressor and the suction port of the compressor.
It is provided with a control device configured to control the opening degree of the flow control valve and switch the operation mode.
The operation mode further includes a pressure equalizing mode.
In the pressure equalization mode, the flow control valve is opened, and the flow path resistance of the flow control valve corresponding to the opening degree is larger than the flow path resistance of the flow path switching device.
The control device is configured to switch the operation mode in the order of the heating mode, the pressure equalizing mode, and the defrosting mode.
The height of the first heat exchanger is lower than the height of the flow path switching device.
The height of the connection portion between the first flow path connecting the suction port and the flow path switching device and the second flow path through which the refrigerant from the flow control valve passes and connects to the first flow path. It is lower than the height of the flow switching device, refrigerating cycle apparatus. In the connection portion between the first flow path connecting the suction port and the flow path switching device and the second flow path through which the refrigerant from the flow control valve passes and connects to the first flow path, the said The refrigeration cycle apparatus according to claim 1, wherein the angle formed by the first flow path and the second flow path is larger than 0 degrees and smaller than 180 degrees. The area of the passage portion of the refrigerant in the cross section of the first flow path orthogonal to the traveling direction of the refrigerant moving in the first flow path connected to the flow control valve is the area of the passage portion of the refrigerant in the second flow connected to the suction port. The refrigeration cycle apparatus according to claim 1, wherein the area is smaller than the area of the passage portion of the refrigerant in the cross section of the second flow path orthogonal to the traveling direction of the refrigerant moving on the path. The refrigeration cycle device according to any one of claims 1 to 14 , wherein in the pressure equalization mode, the Cv value of the flow control valve is smaller than the Cv value of the flow path switching device.

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