WO2012160832A1

WO2012160832A1 - Refrigeration cycle device

Info

Publication number: WO2012160832A1
Application number: PCT/JP2012/003430
Authority: WO
Inventors: 岡市　敦雄; 修小須田; 拓也奥村; 嘉久和　孝; 谷口　和宏
Original assignee: パナソニック株式会社
Priority date: 2011-05-26
Filing date: 2012-05-25
Publication date: 2012-11-29
Also published as: CN103492817A; EP2716999A4; JPWO2012160832A1; JP5971633B2; CN103492817B; EP2716999A1

Abstract

A refrigeration cycle device (100) is equipped with a volume control compressor (101), a volume control passage (111), a four-way valve (flow path switching unit) (112), a high-pressure introduction passage (114), a low-pressure introduction passage (116), and a check valve (120). When the load is small, the four-way valve (112) is controlled such that the volume control passage (111) is connected to the low-pressure introduction passage (116). When the load is large, the four-way valve (112) is controlled such that the volume control passage (111) is connected to the high-pressure introduction passage (114). The high-pressure introduction passage (114) is provided with the check valve (120), which allows the circulation of refrigerant from a flow path (10a) to the four-way valve (112) and prevents circulation in the opposite direction.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus. The present invention particularly relates to a refrigeration cycle apparatus including a volume control compressor.

A volume control compressor capable of changing the suction volume (exclusion volume) has been conventionally known. Volumetric control technology for compressors was actively studied before inverters were widely used. However, the importance of volumetric control technology was temporarily increased after high-performance inverters became available at low cost. It was falling. Recently, in order to promote further energy saving, compressor volume control technology has begun to attract attention again. An example of the volume control technique will be introduced with reference to FIG.

FIG. 9 is a configuration diagram of the air conditioner described in Patent Document 1. The air conditioner 600 includes a volume control compressor 622, a four-way valve 623, an outdoor heat exchanger 624, an expansion means 625, an indoor heat exchanger 641, an accumulator 621, a bypass pipe 688, a flow path switching valve 690, a suction pipe 628, and a discharge. A pipe 630 is provided. A bypass discharge valve (not shown) is provided at a connection portion between the volume control compressor 622 and the bypass pipe 688.

When the air conditioning load is small, the bypass pipe 688 is connected to the suction pipe 628 by the flow path switching valve 690. As a result, a part of the suction refrigerant is returned to the suction pipe 628 via the bypass pipe 688, and operation at a low volume becomes possible. On the other hand, when the air conditioning load is large, the bypass pipe 688 is connected to the discharge pipe 630 by the flow path switching valve 690. At this time, the bypass discharge valve is closed with the refrigerant having the discharge pressure.

JP 2008-240699 A

When applying the volume control described with reference to FIG. 9, a large amount of oil may flow out from the compressor.

The present invention solves such problems, and provides a refrigeration cycle apparatus that can reduce the amount of oil flowing out of a volume control compressor and exhibit high equipment efficiency (COP (coefficient of performance) of the refrigeration cycle). The purpose is to do.

That is, this disclosure
A compression chamber, a bypass discharge port that opens to the compression chamber, and a bypass discharge valve that opens and closes the bypass discharge port, and the refrigerant sucked into the compression chamber maintains the suction pressure while the bypass discharge port. A volume control compressor configured to be able to change a suction volume by being discharged from the compression chamber through an outlet;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the compression chamber;
A discharge path for guiding the compressed refrigerant from the compression chamber to the radiator;
A volume control path connected to the bypass discharge port;
A flow path switching unit that supplies either the discharge pressure of the compressor or the suction pressure of the compressor to the volume control path as a control pressure;
A high-pressure introduction path having one end connected to the flow path switching unit and the other end connected to the discharge path;
A low-pressure introduction path having one end connected to the flow path switching unit and the other end connected to the suction path;
When the load of the refrigeration cycle apparatus is small, the flow path switching unit is controlled so that the volume control path is connected to the low pressure introduction path. When the load is large, the volume control path is A control device for controlling the flow path switching unit to be connected to the high-pressure introduction path;
A check valve provided in the high-pressure introduction path, allowing a refrigerant flow from the discharge path to the flow path switching unit, and prohibiting a reverse flow;
A refrigeration cycle apparatus is provided.

According to the refrigeration cycle apparatus of the present disclosure, the check valve is provided in the high pressure introduction path. Therefore, even when a high internal pressure of the compression chamber acts on the bypass discharge port, the internal pressure of the compression chamber is blocked by the check valve. Since the volume control path is filled with the refrigerant having the internal pressure of the compression chamber, the bypass discharge valve is also closed. Thereby, excessive oil discharge to the refrigerant circuit can be prevented. As a result, the heat transfer in the heat exchanger is improved and the pressure loss when the refrigerant passes through the pipe is also reduced, so that the coefficient of performance (COP) of the refrigeration cycle is improved.

The block diagram of the refrigerating-cycle apparatus which concerns on Embodiment 1 of this invention. Schematic cross-sectional view of the volume control compressor used in the refrigeration cycle apparatus shown in FIG. The block diagram which shows the driving | operation in the low volume mode of the refrigeration cycle apparatus shown in FIG. Configuration diagram of refrigeration cycle apparatus according to Modification 1 Configuration diagram of refrigeration cycle apparatus according to modification 2 Schematic longitudinal sectional view of the volume control compressor used in the refrigeration cycle apparatus shown in FIG. The block diagram of the refrigerating-cycle apparatus which concerns on Embodiment 2 of this invention. Configuration diagram of refrigeration cycle apparatus according to modification 3 Configuration diagram of conventional air conditioner

The problem of conventional volume control will be explained in detail. When the volume control described with reference to FIG. 9 is applied, the following problems are expected to occur. For example, when the position of the bypass discharge valve is close to the discharge port of the compression chamber, the pressure acting on the bypass discharge valve (the internal pressure of the compression chamber) may exceed the discharge pressure. This is because pressure loss occurs in the path from the compression chamber to the discharge pipe. Therefore, the internal pressure of the compression chamber is higher than the discharge pressure by an amount corresponding to the pressure loss. When the internal pressure of the compression chamber acting on the bypass discharge valve exceeds the discharge pressure, the bypass discharge valve cannot maintain the closed state.

When the bypass discharge valve cannot be kept closed, a large amount of oil flows into the discharge pipe through the bypass pipe, and the amount of oil circulating in the refrigerant circuit increases. A large amount of oil that has flowed out of the compressor hinders heat transfer in the heat exchanger, increases the pressure loss when the refrigerant passes through the pipe, and decreases the efficiency of the refrigeration cycle. This problem can be solved by the following disclosure.

The first aspect of the present disclosure is:
A compression chamber, a bypass discharge port that opens to the compression chamber, and a bypass discharge valve that opens and closes the bypass discharge port, and the refrigerant sucked into the compression chamber maintains the suction pressure while the bypass discharge port. A volume control compressor configured to be able to change a suction volume by being discharged from the compression chamber through an outlet;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the compression chamber;
A discharge path for guiding the compressed refrigerant from the compression chamber to the radiator;
A volume control path connected to the bypass discharge port;
A flow path switching unit that supplies either the discharge pressure of the compressor or the suction pressure of the compressor to the volume control path as a control pressure;
A high-pressure introduction path having one end connected to the flow path switching unit and the other end connected to the discharge path;
A low-pressure introduction path having one end connected to the flow path switching unit and the other end connected to the suction path;
When the load of the refrigeration cycle apparatus is small, the flow path switching unit is controlled so that the volume control path is connected to the low pressure introduction path. When the load is large, the volume control path is A control device for controlling the flow path switching unit to be connected to the high-pressure introduction path;
A check valve provided in the high-pressure introduction path, allowing a refrigerant flow from the discharge path to the flow path switching unit, and prohibiting a reverse flow;
A refrigeration cycle apparatus is provided.

The second aspect provides a refrigeration cycle apparatus, in addition to the first aspect, in which the compressor may further include a suction port and a discharge port. When the load is small, a part of the refrigerant sucked into the compression chamber from the suction port is discharged from the compression chamber through the bypass discharge port while maintaining the suction pressure, and from the suction port to the compression chamber The remaining portion of the refrigerant sucked in can be compressed in the compression chamber and discharged from the compression chamber through the discharge port. The refrigerant discharged from the compression chamber through the bypass discharge port is returned to the suction path. Therefore, unnecessary compression work is not performed by the compressor.

3rd aspect provides the refrigerating-cycle apparatus which may be further provided with the relief valve circuit in addition to the 1st or 2nd aspect. The high-pressure introduction path may include a first part between the check valve and the flow path switching unit and a second part between the check valve and the discharge path. The relief valve circuit may have one end connected to the first part and the other end connected to the second part or the discharge path. According to the relief valve circuit, it is possible to prevent an excessive increase in pressure in the volume control path, the flow path switching unit, and the first portion of the high pressure introduction path by letting the pressure escape to the second part or the discharge path.

In the fourth aspect, in addition to the first aspect, the compressor is compressed by the first compression chamber and the second compression chamber as the compression chamber, the refrigerant compressed in the first compression chamber, and the second compression chamber. A closed container including an internal space capable of holding the refrigerant, an intermediate chamber that receives the refrigerant discharged from the first compression chamber through the bypass discharge port, and the intermediate chamber and the internal space of the closed container are communicated with each other. There is provided a refrigeration cycle apparatus that may be a hermetic multi-cylinder compressor further including a first discharge port that performs and a first discharge valve that opens and closes the first discharge port. The volume control path may be connected to the bypass discharge port via the intermediate chamber. When the load is small, the refrigerant sucked into the first compression chamber is discharged from the first compression chamber through the bypass discharge port while maintaining the suction pressure, and the intermediate chamber, the volume control path, and the It can be returned to the suction path through the low pressure introduction path. When the load is large, the refrigerant sucked into the first compression chamber is compressed to a pressure exceeding the discharge pressure in the first compression chamber, pushes open the bypass discharge valve and the first discharge valve, The air can be discharged from the first compression chamber to the internal space of the sealed container through the bypass discharge port, the intermediate chamber, and the first discharge port. According to the fourth aspect, a so-called cylinder-less volume control compressor can be provided.

In a fifth aspect, in addition to any one of the first to fourth aspects, the control device is configured to connect the volume control path to the low pressure introduction path when the refrigeration cycle apparatus is activated. Provided is a refrigeration cycle apparatus capable of controlling a switching unit and controlling the flow path switching unit to connect the volume control path to the high-pressure introduction path after an arbitrary time has elapsed. By executing such control, even if the liquid refrigerant is accumulated in the volume control path, the liquid refrigerant can be quickly returned to the suction path. As a result, abnormal pressure is generated due to liquid refrigerant confined in the volume control path, that is, the temperature of the liquid refrigerant rises after startup and the liquid refrigerant expands to prevent excessive pressure increase in the volume control path. it can.

In a sixth aspect, in addition to any one of the first to fifth aspects, the control device is configured to connect the volume control path to the low-pressure introduction path when stopping the operation of the refrigeration cycle apparatus. A refrigeration cycle apparatus capable of controlling a flow path switching unit is provided. In this way, abnormal pressure is generated due to the liquid refrigerant being confined in the volume control path, that is, the temperature of the liquid refrigerant rises after startup and the liquid refrigerant expands, thereby excessively increasing the pressure in the volume control path. Can be prevented.

The seventh aspect of the present disclosure is:
A compression chamber, a bypass discharge port that opens to the compression chamber, and a bypass discharge valve that opens and closes the bypass discharge port, and the refrigerant sucked into the compression chamber maintains the suction pressure while the bypass discharge port. A volume control compressor configured to be able to change a suction volume by being discharged from the compression chamber through an outlet;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the compression chamber;
A discharge path for guiding the compressed refrigerant from the compression chamber to the radiator;
A volume control path connected to the bypass discharge port;
A low-pressure introduction path connected to the suction path;
An on-off valve provided to connect the low-pressure introduction path and the volume control path;
When the load of the refrigeration cycle apparatus is small, the on-off valve is controlled to connect the volume control path to the low pressure introduction path, and when the load is large, the volume control path is changed to the low pressure introduction path. A control device for controlling the on-off valve so as to be separated from
A relief valve circuit having one end connected to the volume control path and the other end connected to the discharge path;
A refrigeration cycle apparatus is provided.

According to the seventh aspect, the volume control path is connected to the low pressure introduction path via the on-off valve. Therefore, it can be avoided that the refrigerant containing a large amount of oil flows directly into the discharge path of the compressor through the bypass discharge port and the volume control path. Further, since the relief valve circuit is provided, even if the temperature of the liquid refrigerant temporarily accumulated in the volume control path rises and the liquid refrigerant expands to increase the pressure of the volume control path, the relief valve circuit Through the circuit, pressure can be released to the discharge path.

The eighth aspect of the present disclosure is:
A first compression chamber; a second compression chamber; a sealed container including an internal space capable of holding the refrigerant compressed in the first compression chamber and the refrigerant compressed in the second compression chamber; and the first compression chamber A bypass discharge opening that opens to the opening, a bypass discharge valve that opens and closes the bypass discharge opening, an intermediate chamber that receives the refrigerant discharged from the first compression chamber through the bypass discharge opening, the intermediate chamber, and the sealed container A volume control compressor having a first discharge port that communicates with the internal space, and a first discharge valve that opens and closes the first discharge port;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the first compression chamber and the second compression chamber;
A discharge path for guiding the compressed refrigerant from the first compression chamber and the second compression chamber to the radiator;
A volume control path connected to the bypass outlet through the intermediate chamber;
A low-pressure introduction path connected to the suction path;
An on-off valve provided to connect the low-pressure introduction path and the volume control path;
(I) When the load of the refrigeration cycle apparatus is small, the volume control path is connected to the low pressure introduction path, so that the refrigerant sucked into the first compression chamber maintains the suction pressure and the bypass Controlling the on-off valve so that it is discharged from the first compression chamber through a discharge port and returned to the suction passage through the intermediate chamber, the volume control path, and the low-pressure introduction path, and (ii) when the load is large By separating the volume control path from the low-pressure introduction path, the refrigerant sucked into the first compression chamber is compressed to a pressure exceeding the discharge pressure of the compressor in the first compression chamber, and the bypass discharge valve And the first discharge valve is pushed open and discharged from the first compression chamber to the internal space of the sealed container through the bypass discharge port, the intermediate chamber, and the first discharge port. A control device for controlling the opening and closing valve so,
A refrigeration cycle apparatus is provided.

According to the eighth aspect, the volume control path is connected to the low pressure introduction path via the on-off valve. Therefore, it can be avoided that the refrigerant containing a large amount of oil flows directly into the discharge path of the compressor through the bypass discharge port and the volume control path. Furthermore, according to the eighth aspect, it is possible to avoid the formation of a closed space in the refrigerant circuit. Therefore, even if the volume control path is filled with the liquid refrigerant, and then the temperature of the liquid refrigerant rises and the liquid refrigerant expands, the pressure in the volume control path cannot increase excessively. This is because when the pressure in the volume control path increases, the first discharge valve opens and the pressure can be released to the internal space of the sealed container.

In a ninth aspect, in addition to the seventh or eighth aspect, the control device controls the open / close valve so as to connect the volume control path to the low-pressure introduction path when the refrigeration cycle apparatus is started, and thereafter Provided is a refrigeration cycle apparatus that controls the on-off valve so that the volume control path is disconnected from the low-pressure introduction path when an arbitrary time has elapsed. According to the ninth aspect, the same effect as in the sixth aspect can be obtained.

In a tenth aspect, in addition to any one of the seventh to ninth aspects, the control device is configured to connect the volume control path to the low-pressure introduction path when stopping the operation of the refrigeration cycle apparatus. A refrigeration cycle apparatus for controlling an on-off valve is provided. In this way, abnormal pressure is generated due to the liquid refrigerant being confined in the volume control path, that is, the temperature of the liquid refrigerant rises after startup and the liquid refrigerant expands, thereby excessively increasing the pressure in the volume control path. Can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by the following embodiment.

(Embodiment 1)
As shown in FIG. 1, the refrigeration cycle apparatus 100 of the present embodiment includes a volume control compressor 101, a first four-way valve 102, a first heat exchanger 103, an expansion mechanism 104, a second heat exchanger 105, and an accumulator 106. I have. These components are connected to each other by flow paths 10a to 10f so as to form a refrigerant circuit. The flow paths 10a to 10f are each constituted by a refrigerant pipe.

The first heat exchanger 103 is a radiator that cools the refrigerant compressed by the compressor 101 or an evaporator that heats the refrigerant expanded by the expansion mechanism 104. The second heat exchanger 105 is an evaporator when the first heat exchanger 103 is a radiator, and is a radiator when the first heat exchanger 103 is an evaporator. The expansion mechanism 104 has a function of expanding the refrigerant cooled by the radiator, and is typically composed of an expansion valve. The expansion mechanism 104 may be composed of a positive displacement expander that can recover the expansion energy of the refrigerant.

The compressor 101 is a hermetic compressor, and includes a hermetic container 1, a motor 2, and a compression mechanism 3. The motor 2 and the compression mechanism 3 are disposed in the sealed container 1. The sealed container 1 has an internal space 28 that can hold the refrigerant compressed by the compression mechanism 3. That is, the compressor 101 is a so-called high pressure shell type compressor. The compression mechanism 3 is connected to the motor 2 by a shaft 4. The compression mechanism 3 is a positive displacement fluid mechanism and is moved by the motor 2 so as to compress the refrigerant.

As shown in FIG. 2, the compression mechanism 3 includes a suction port 27, a discharge port 29, a compression chamber 25, a bypass discharge port 16 that opens to the compression chamber 25, and a bypass discharge valve 35 that opens and closes the bypass discharge port 16. ing. When the compressor 101 is operated in the high volume mode, the entire amount of refrigerant sucked into the compression chamber 25 from the suction port 27 is compressed in the compression chamber 25 and discharged to the internal space 28 of the sealed container 1 through the discharge port 29. On the other hand, when the compressor 101 is operated in the low volume mode, a part of the refrigerant sucked into the compression chamber 25 from the suction port 27 pushes the bypass discharge valve 35 open and is discharged from the compression chamber 25 through the bypass discharge port 16. . The suction volume of the compressor 101 is changed by switching between the high volume mode and the low volume mode.

Specifically, when the compressor 101 is operated in the low volume mode, a part of the refrigerant sucked into the compression chamber 25 from the suction port 27 maintains the suction pressure (without being substantially compressed) and bypasses. It is discharged from the compression chamber 25 through the discharge port 16. The remaining portion of the refrigerant sucked into the compression chamber 25 from the suction port 27 is compressed in the compression chamber 25 and discharged from the compression chamber 25 through the discharge port 29. The refrigerant discharged from the compression chamber 25 through the bypass discharge port 16 is returned to the flow path 10e as the suction path, as will be described later. Therefore, unnecessary compression work is not performed by the compressor 101.

The bypass discharge valve 35 is composed of a reed valve including a reed 36 and a valve stop 37. The lead 36 and the valve stop 37 are fixed to the cylinder 5 by fixing parts 38 such as screws and bolts. The bypass discharge valve 35 opens and closes due to a pressure difference between the front surface and the back surface of the lead 36. Any of the several discharge valves described herein may be a reed valve.

The compression mechanism 3 includes a cylinder 5, a piston 8, a vane 9, and a spring 10. An upper bearing and a lower bearing are disposed at the upper and lower portions of the cylinder 5 so as to close the cylinder 5 (not shown). A piston 8 fitted to the eccentric portion 4 a of the shaft 4 is disposed inside the cylinder 5 so that the compression chamber 25 is formed inside the cylinder 5. A vane groove 24 is formed in the cylinder 5. The vane groove 24 accommodates a vane 9 having a tip that contacts the outer peripheral surface of the piston 8. The spring 10 is disposed in the vane groove 24 so as to push the vane 9 toward the piston 8. The compression chamber 25 between the cylinder 5 and the piston 8 is partitioned by the vane 9, thereby forming a suction chamber 25a and a compression-discharge chamber 25b. The refrigerant to be compressed is guided to the compression chamber 25 (suction chamber 25a) through the flow path 10f and the suction port 27. The compressed refrigerant is guided from the compression chamber 25 (compression-discharge chamber 25b) to the internal space 28 of the sealed container 1 through the discharge port 29. The discharge port 29 is provided with a discharge valve (not shown). The vane 9 may be integrated with the piston 8. That is, the piston 8 and the vane 9 may be configured as a so-called swing piston.

In the present embodiment, the position of the bypass discharge port 16 is determined so that the suction volume in the low volume mode is ½ of the suction volume in the high volume mode. However, the position of the bypass discharge port 16 is not limited, and is determined according to the suction volume required in the low volume mode. Two or more bypass discharge ports 16 may be provided. In this case, the compressor 101 can be operated with one suction volume selected from a plurality of suction volumes.

In this embodiment, the compressor 101 is a rotary compressor, but the type of the compressor 101 is not particularly limited as long as the suction volume can be changed. Other types of compressors such as a scroll compressor and a reciprocating compressor described in Patent Document 1 (Japanese Patent Laid-Open No. 2008-240699) can be used.

As shown in FIG. 1, the flow path 10a forms a discharge path that guides the refrigerant compressed by the compressor 101 from the compression chamber 25 to the radiator (the first heat exchanger 103 or the second heat exchanger 105). Yes. The flow path 10e, the accumulator 106, and the flow path 10f form a suction path that guides the refrigerant to be compressed from the evaporator (the first heat exchanger 103 or the second heat exchanger 105) to the compression chamber 25.

The refrigeration cycle apparatus 100 further includes a volume control path 111, a second four-way valve 112, a high pressure introduction path 114, a low pressure introduction path 116, a check valve 120, and a control device 117.

The volume control path 111 is connected to the bypass discharge port 16 of the compressor 101. The second four-way valve 112 is a flow path switching unit that supplies either the discharge pressure of the compressor 101 or the suction pressure of the compressor 101 to the volume control path 111 as a control pressure. The high-pressure introduction path 114 has one end connected to the second four-way valve 112 and the other end connected to the flow path 10a. The low-pressure introduction path 116 has one end connected to the second four-way valve 112 and the other end connected to the flow path 10e. The check valve 120 is provided in the high-pressure introduction path 114 so as to allow a refrigerant flow from the flow path 10a to the second four-way valve 112 and prohibit a reverse flow. Each of the

paths

111, 114, and 116 can be configured by a refrigerant pipe.

In the present embodiment, the second four-way valve 112 in which one connection port is blocked is used as the flow path switching unit. However, the structure of the flow path switching unit is not limited as long as either the discharge pressure of the compressor 101 or the suction pressure of the compressor 101 can be supplied to the volume control path 111 as a control pressure. The other end of the low-pressure introduction path 116 may be connected to the accumulator 106 or may be connected to the flow path 10f.

The control device 117 controls the second four-way valve 112 so that the suction volume of the compressor 101 increases or decreases according to the load of the refrigeration cycle apparatus 100. Specifically, the control device 117 controls the second four-way valve 112 so that the volume control path 111 is connected to the low pressure introduction path 116 when the load is small, and the volume control path when the load is large. The second four-way valve 112 is controlled so that 111 is connected to the high-pressure introduction path 114. The control device 117 can be configured by a DSP (Digital Signal Processor) including an A / D conversion circuit, an input / output circuit, an arithmetic circuit, a storage device, and the like. The control device 117 may include a drive circuit that controls the motor 2 of the compressor 101.

Next, the operation of the refrigeration cycle apparatus 100 will be described.

When the motor 2 of the compressor 101 is started, the compressor 101 sucks low-pressure gas refrigerant through the flow path 10f (suction path) and compresses it. The high-pressure gas refrigerant is discharged into the internal space 28 of the sealed container 1, passes through the internal space 28 of the sealed container 1, the flow path 10 a, the first four-way valve 102, and the flow path 10 b, and then passes through the first heat exchanger 103 (heat radiator). ). In the first heat exchanger 103, the refrigerant is cooled and condensed. The high-pressure liquid refrigerant is guided from the first heat exchanger 103 to the expansion mechanism 104 and decompressed by the function of the expansion mechanism 104. The gas-liquid two-phase refrigerant is led from the expansion mechanism 104 to the second heat exchanger 105 (evaporator), heated by the second heat exchanger 105, and evaporated. The gas refrigerant is again sucked into the compressor 101 through the accumulator 106.

The compressor 101 is configured to change the suction volume using the discharge pressure and the suction pressure. When the second four-way valve 112 is maintained in the state shown in FIG. 1, the discharge pressure of the compressor 101 is supplied to the volume control path 111. In this case, since the bypass discharge valve 35 is closed, the compressor 101 is operated with a relatively large suction volume (high volume mode).

When the load of the refrigeration cycle apparatus 100 is reduced, the number of rotations of the motor 2 of the compressor 101 is reduced by the inverter. Thereby, the capacity | capacitance of the refrigerating-cycle apparatus 100 reduces, and an efficient driving | operation is performed. However, when the load further decreases, the rotational speed of the motor 2 reaches the lower limit value, and it becomes difficult to follow the capacity further.

When operation with a lower capacity is required, the control device 117 switches the second four-way valve 112 from the state shown in FIG. 1 to the state shown in FIG. Then, the volume control path 111 is disconnected from the high pressure introduction path 114 and connected to the low pressure introduction path 116. As a result, the suction pressure of the compressor 101 is supplied to the volume control path 111. The suction pressure of the compressor 101 acts on the bypass discharge valve 35. In this case, when the volume of the compression chamber 25 is reduced, the bypass discharge valve 35 opens as the refrigerant in the compression chamber 25 is pushed away by the piston 8. During the period in which the bypass discharge valve 35 is open and the bypass discharge port 16 and the compression chamber 25 communicate with each other, the refrigerant sucked into the compression chamber 25 passes through the volume control path 111, the second four-way valve 112, and the low pressure introduction path 116. , Returned to the flow path 10e. That is, the compressor 101 is operated with a relatively small suction volume (low volume mode).

Assuming that the rotation speed of the compressor 101 is constant, the refrigerant discharge amount from the compressor 101 in the low volume mode is smaller than the refrigerant discharge amount in the high volume mode. Therefore, by switching the operation mode between the high volume mode and the low volume mode, the range in which the ability can be followed, particularly the lower limit value, is expanded.

In this embodiment, a check valve 120 is provided in the high pressure introduction path 114. In the high volume mode shown in FIG. 1, even if the internal pressure of the compression chamber 25 exceeds the discharge pressure and high-pressure refrigerant is discharged from the compression chamber 25 through the bypass discharge port 16, the high-pressure refrigerant is blocked by the check valve 120. Can be stopped. Since the check valve 120 does not allow the flow from the volume control path 111 to the flow path 10a, the check valve 120 closes the high pressure introduction path 114. Thereby, the refrigerant containing a large amount of oil is discharged from the compressor 101, and a large amount of oil can be prevented from circulating in the refrigerant circuit. As a result, the heat transfer in the

heat exchangers

103 and 105 is improved, and the pressure loss when the refrigerant passes through the flow paths 10a to 10f is reduced, so that the coefficient of performance (COP) of the refrigeration cycle is improved. Since the volume control path 111, the second four-way valve 112, and a part of the high pressure introduction path 114 are filled with the highest pressure refrigerant among the refrigerant compressed in the compression chamber 25, the closed state of the bypass discharge valve 35 can also be maintained. .

In addition, the control device 117 controls the second four-way valve 112 so that the volume control path 111 is connected to the low pressure introduction path 116 when the refrigeration cycle apparatus 100 is started up, and thereafter, for an arbitrary time (for example, 1 to 5 minutes). ), The second four-way valve 112 is controlled so that the volume control path 111 is connected to the high pressure introduction path 114. Specifically, after an arbitrary time has elapsed since the start of the motor 2, the operation in the low volume mode should be performed or the operation in the high volume mode should be performed depending on the capacity required for the refrigeration cycle apparatus 100. Determine what to do. When the operation in the high volume mode is to be performed, the volume control path 111 is connected to the high pressure introduction path 114. When the operation in the low volume mode is to be performed, the connection between the volume control path 111 and the low pressure introduction path 116 is maintained. That is, the preliminary operation in the low volume mode is performed at the time of startup.

If the ambient temperature is low, liquid refrigerant may accumulate in the volume control path 111 in winter, for example. If the preliminary operation is performed, even if liquid refrigerant is accumulated in the volume control path 111, the liquid refrigerant can be quickly returned to the flow path 10e. As a result, the generation of abnormal pressure due to the liquid refrigerant being confined in the volume control path 111, that is, the temperature of the liquid refrigerant rises after startup and the liquid refrigerant expands, thereby increasing the pressure of the volume control path 111 excessively. Can be prevented. Further, from the viewpoint of preliminary operation, the low-pressure introduction path 116 is preferably connected to the flow path 10e or the accumulator 106. Thereby, it can prevent that a liquid refrigerant is supplied to the compressor 101 at the time of starting.

Preliminary operation is performed when the refrigeration cycle apparatus 100 is activated, but the “activation of the refrigeration cycle apparatus 100” may include restart after a temporary stop. The preliminary operation can also be applied to other embodiments and modifications described in this specification.

The control device 117 may control the second four-way valve 112 so as to connect the volume control path 111 to the low pressure introduction path 116 when the operation of the refrigeration cycle apparatus 100 is stopped. Specifically, it is desirable to stop the operation of the refrigeration cycle apparatus 100 in a state where the volume control path 111 is connected to the low pressure introduction path 116. In this way, abnormal pressure is generated due to the liquid refrigerant being confined in the volume control path 111, that is, the pressure of the volume control path 111 is excessive due to the temperature of the liquid refrigerant rising and the liquid refrigerant expanding after startup. Can be prevented.

(Modification 1)
As shown in FIG. 4, the refrigeration cycle apparatus 200 according to Modification 1 is different from the refrigeration cycle apparatus 100 of Embodiment 1 in that it further includes a relief valve circuit 221. In the following description, the same reference numerals are assigned to components common to the previous embodiment or modification and the subsequent embodiment or modification, and description thereof is omitted.

The high pressure introduction path 114 includes a first portion 114a between the check valve 120 and the second four-way valve 112 (flow path switching unit), and a second portion between the check valve 120 and the flow path 10a (discharge path). Part 114b. The relief valve circuit 221 has one end connected to the first portion 114a and the other end connected to the second portion 114b or the flow path 10a so as to bypass the check valve 120. When the difference between the pressure of the first portion 114a and the pressure of the second portion 114b exceeds a certain value, the relief valve circuit 221 causes the refrigerant to flow from the first portion 114a to the flow path 10a (or the second portion 114b), The pressure in the first portion 114a is lowered.

According to the refrigeration cycle apparatus 200, the same effect as the preliminary operation described in the first embodiment can be obtained. That is, the generation of abnormal pressure due to the liquid refrigerant being confined in the volume control path 111 or the like can be prevented. When the ambient temperature is low, for example, in winter, liquid refrigerant may accumulate in the volume control path 111, the four-way valve 112, and the first portion 114a of the high-pressure introduction path 114. The phenomenon that the liquid refrigerant is accumulated in the volume control path 111 or the like is predicted to occur when the path from the bypass discharge valve 35 to the check valve 120 is cooled. Further, liquid refrigerant may accumulate in the volume control path 111 and the like while the compressor 101 is stopped. When liquid refrigerant is accumulated in a closed space such as the volume control path 111, the temperature of the liquid refrigerant rises and the liquid refrigerant expands, so that the pressure in the closed space such as the volume control path 111 is increased. May go up excessively. According to the relief valve circuit 221, it is possible to prevent an excessive increase in pressure in the volume control path 111, the four-way valve 112, and the first portion 114a of the high pressure introduction path 114 by letting the pressure escape to the flow path 10a.

(Modification 2)
As shown in FIG. 5, the refrigeration cycle apparatus 300 according to the second modification is different from the first embodiment in that it includes a compressor 301 having a structure different from that of the compressor 101 in the first embodiment.

As shown in FIG. 6, the compressor 301 includes a sealed container 1, a motor 2, and a compression mechanism 30, and is configured as a multi-cylinder rotary compressor (two cylinders in this modification). The refrigerant compressed by the compression mechanism 30 is guided to the flow path 10 a through the internal space 28 of the sealed container 1. The compression mechanism 30 includes a first compression chamber 40, a second compression chamber 42, an intermediate chamber 69, a first discharge port 67, a first discharge valve 63, a second discharge port 71, a second discharge valve 73, a bypass discharge port 65, and A bypass discharge valve 61 is provided.

The flow path 10a forms a discharge path that guides the refrigerant compressed by the compressor 301 from the first compression chamber 40 and the second compression chamber 42 to the radiator (the first heat exchanger 103 or the second heat exchanger 105). ing. The flow path 10e, the accumulator 106, and the flow path 10f are suction paths that guide the refrigerant to be compressed from the evaporator (the first heat exchanger 103 or the second heat exchanger 105) to the first compression chamber 40 and the second compression chamber 42. Is forming.

The bypass discharge port 65 is open to the first compression chamber 40. A bypass discharge valve 61 is provided so as to open and close the bypass discharge port 65. The intermediate chamber 69 is a space that receives the refrigerant discharged from the first compression chamber 40 through the bypass discharge port 65. The first discharge port 67 allows the intermediate chamber 69 and the internal space 28 of the sealed container 1 to communicate with each other. A first discharge valve 63 is provided to open and close the first discharge port 67. The volume control path 111 is connected to the bypass discharge port 65 via the intermediate chamber 69. Thus, the compressor 301 is provided with the two

discharge valves

61 and 63 on the path from the first compression chamber 40 to the internal space 28 of the sealed container 1. A volume control path 111 is connected to a space (intermediate chamber 69) between the discharge valve 61 and the discharge valve 63.

The compression mechanism 30 also includes a first cylinder 41, an intermediate plate 71, a second cylinder 43, a first piston 51, a second piston 53, an upper bearing 46, a lower bearing 48, a muffler 77, and a muffler 75. The first piston 51 is fitted into the first eccentric portion 4 a of the shaft 4 inside the first cylinder 41. A first compression chamber 40 is formed between the outer peripheral surface of the first piston 51 and the inner peripheral surface of the first cylinder 41. The second cylinder 43 is disposed concentrically with the first cylinder 41. The second piston 53 is fitted into the second eccentric portion 4 b of the shaft 4 inside the second cylinder 43. A second compression chamber 42 is formed between the outer peripheral surface of the second piston 53 and the inner peripheral surface of the second cylinder 43.

The upper bearing 46 and the lower bearing 48 are arranged at the upper part of the first cylinder 41 and the lower part of the second cylinder 43, respectively. The intermediate plate 71 is disposed between the first cylinder 41 and the second cylinder 43. The first cylinder 41 is closed by the upper bearing 46 and the middle plate 71, and the second cylinder 43 is closed by the middle plate 71 and the lower bearing 48. A path that passes through the upper bearing 46 along the axial direction of the shaft 4 is formed by the bypass discharge port 65, the intermediate chamber 69, and the first discharge port 67. A muffler 77 is disposed on the upper bearing 46. In the high volume mode, the refrigerant compressed in the first compression chamber 40 is guided to the internal space 28 of the sealed container 1 through the internal space of the bypass discharge port 65, the intermediate chamber 69, the first discharge port 67 and the muffler 77. The second discharge port 71 is formed in the lower bearing 48 such that a path that penetrates the lower bearing 48 along the axial direction of the shaft 4 is formed. A muffler 75 is disposed below the lower bearing 48. The internal space of the muffler 75 communicates with the internal space of the muffler 77 through a vertical path (not shown). The refrigerant compressed in the second compression chamber 42 is guided to the internal space 28 of the sealed container 1 through the second discharge port 71, the internal space of the muffler 75, the vertical path, and the internal space of the muffler 77.

The first compression chamber 40 and the second compression chamber 42 function as mutually independent compression chambers. In the high volume mode, the refrigerant is compressed in each of the first compression chamber 40 and the second compression chamber 42. In the low volume mode, the refrigerant is compressed in the second compression chamber 42, but the refrigerant is not compressed in the first compression chamber 40. In the low volume mode, the suction pressure is supplied to the intermediate chamber 69, so that the refrigerant sucked into the first compression chamber 40 pushes and opens the bypass discharge valve 61 without being compressed, thereby bypassing the bypass discharge port 65 and the intermediate chamber 69. To the volume control path 111. As described above, the compressor 301 is configured as a so-called cylinderless volume control compressor.

Next, the operation of the refrigeration cycle apparatus 300 will be described.

When the motor 2 is started, the compressor 301 sucks in and compresses the low-pressure gas refrigerant through the flow path 10f (suction path). The high-pressure gas refrigerant is discharged into the internal space 28 of the sealed container 1. Specifically, the refrigerant compressed in the first compression chamber 40 is discharged into the internal space 28 of the sealed container 1 through the bypass discharge port 65, the intermediate chamber 69, the first discharge port 67 and the muffler 77. The refrigerant compressed in the second compression chamber 42 is discharged into the internal space 28 of the sealed container 1 through the second discharge port 71 and the muffler 75. In the internal space 28, the refrigerant compressed in the first compression chamber 40 merges with the refrigerant compressed in the second compression chamber 42. The subsequent refrigerant flow is as described in the first embodiment.

When the second four-way valve 112 is maintained in the state shown in FIG. 5, the discharge pressure of the compressor 301 is supplied to the volume control path 111 and the intermediate chamber 69. In this case, the refrigerant sucked into the first compression chamber 40 is compressed in the first compression chamber 40 to a pressure exceeding the discharge pressure, pushes open the bypass discharge valve 61 and the first discharge valve 63, bypasses the bypass discharge port 65, intermediate It is discharged from the first compression chamber 40 to the internal space 28 of the sealed container 1 through the chamber 69 and the first discharge port 67. Since the compression work of the refrigerant is performed in both the first compression chamber 40 and the second compression chamber 42, the compressor 301 is operated with a relatively large suction volume (high volume mode).

When the load of the refrigeration cycle apparatus 300 decreases, the rotation speed of the motor 2 of the compressor 301 is reduced by the inverter. Thereby, the capacity | capacitance of the refrigerating-cycle apparatus 300 reduces, and an efficient driving | operation is performed. However, when the load further decreases, the rotational speed of the motor 2 reaches the lower limit value, and it becomes difficult to follow the capacity further.

When operation with a lower capacity is required, the control device 117 switches the second four-way valve 112 from the state shown in FIG. 5 to the state shown in FIG. As a result, the volume control path 111 is disconnected from the high pressure introduction path 114 and connected to the low pressure introduction path 116. The suction pressure of the compressor 301 is supplied to the volume control path 111 and the intermediate chamber 69. In this case, the compressor 301 is operated with a relatively small suction volume (low volume mode).

In the low volume mode, since the pressure in the intermediate chamber 69 is equal to the suction pressure, the bypass discharge valve 61 is always open. Therefore, the refrigerant sucked into the first compression chamber 40 is discharged from the first compression chamber 40 to the intermediate chamber 69 through the bypass discharge port 65 while maintaining the suction pressure (without being substantially compressed). Since the high pressure of the internal space 28 of the sealed container 1 is applied to one side of the first discharge valve 63, the first discharge valve 63 does not open. As a result, the refrigerant discharged into the intermediate chamber 69 is returned to the flow path 10e (suction path) through the volume control path 111, the second four-way valve 112, and the low pressure introduction path 116.

As shown in FIG. 5, in the high volume mode, the volume control path 111 is connected to the high pressure introduction path 114. As a result, the pressure in the intermediate chamber 69 becomes equal to the discharge pressure. However, the pressure in the flow path 10 a is slightly lower than the pressure in the internal space 28 of the sealed container 1 due to the effect of pressure loss that inevitably occurs. When the pressure in the intermediate chamber 69 is lower than the pressure in the internal space 28 of the sealed container 1, the first discharge valve 63 is not opened. The refrigerant discharged into the intermediate chamber 69 fills a part of the volume control path 111, the second four-way valve 112, and the high-pressure introduction pipe 114 and is blocked by the check valve 120. Since the check valve 120 does not allow the flow from the volume control path 111 to the flow path 10a, the pressure in the volume control path 111 and the intermediate chamber 69 gradually increases and exceeds the pressure in the internal space 28 of the sealed container 1. As a result, the first discharge valve 63 is opened. Thus, in the high volume mode, the compression work is performed not only in the second compression chamber 42 but also in the first compression chamber 40. In addition, a refrigerant containing a large amount of oil is discharged from the compressor 301, and a large amount of oil can be prevented from circulating in the refrigerant circuit.

Further, according to this modification, a closed space is not formed in the refrigerant circuit. Therefore, even if a part of the volume control path 111, the second four-way valve 112, and the high pressure introduction path 114 is filled with the liquid refrigerant, and then the temperature of the liquid refrigerant rises and the liquid refrigerant expands, the volume control path 111 The pressure cannot rise excessively. When the pressure in the volume control path 111 rises, the first discharge valve 63 is opened, and the pressure can be released to the internal space 28 of the sealed container 1.

According to this modification, the first compression chamber 40 is located closer to the motor 2. Therefore, the bypass path from the first compression chamber 40 to the volume control path 111 is shortened, and the pressure loss in the low volume mode can be reduced. However, the bypass discharge port 65 may be provided in the second compression chamber 42. That is, the compressor 301 may be configured such that the second compression chamber 42 is stopped instead of the first compression chamber 40.

(Embodiment 2)
As shown in FIG. 7, the refrigeration cycle apparatus 400 of the present embodiment is different from the refrigeration cycle apparatus 100 of the first embodiment in that it includes an on-off valve 420 and a relief valve circuit 221 as means for switching the control pressure. The function and effect of the relief valve circuit 221 are as described in the first modification.

The on-off valve 420 is provided so as to connect the low pressure introduction path 116 and the volume control path 111. As the on-off valve 420, an electromagnetic valve can be used. The on-off valve 420 is closed in the high volume mode and opened in the low volume mode. That is, when the load of the refrigeration cycle apparatus 400 is small, the on-off valve 420 is controlled to connect the volume control path 111 to the low pressure introduction path 116, and when the load is large, the volume control path 111 is set to the low pressure introduction path. On-off valve 420 is controlled so as to be disconnected from 116.

According to the present embodiment, the volume control path 111 is connected to the low pressure introduction path 116 via the on-off valve 420. Therefore, it is possible to avoid the refrigerant containing a large amount of oil from directly flowing into the discharge path of the compressor 101 through the bypass discharge port 16 and the volume control path 111.

Also, for the reason described in the second modification, liquid refrigerant may be accumulated in the volume control path 111 also in the refrigeration cycle apparatus 400 of the present embodiment. However, even if the temperature of the liquid refrigerant rises and the liquid refrigerant expands to increase the pressure in the volume control path 111, the pressure can be released to the discharge path (flow path 10a) through the relief valve circuit 221.

In the high volume mode, even if the internal pressure of the compression chamber 25 exceeds the discharge pressure and high-pressure refrigerant is discharged from the compression chamber 25 through the bypass discharge port 16, the high-pressure refrigerant is blocked by the on-off valve 420. Since the volume control path 111 is filled with the highest pressure refrigerant among the refrigerant compressed in the compression chamber 25, the closed state of the bypass discharge valve 35 can be maintained. Thereby, the refrigerant containing a large amount of oil is discharged from the compressor 101, and a large amount of oil can be prevented from circulating in the refrigerant circuit.

(Modification 3)
As shown in FIG. 8, the refrigeration cycle apparatus 500 of Modification 3 is different from the refrigeration cycle apparatus 300 of Modification 2 in that it includes an on-off valve 420 as means for switching the control pressure. That is, in the refrigeration cycle apparatus 500 of this modification, the compressor 101 of the second embodiment is replaced with the compressor 301 of the modification 2, and the relief valve circuit 221 is omitted.

The on-off valve 420 is closed in the high volume mode and opened in the low volume mode. The function of the on-off valve 420 is as described in the second embodiment. According to the refrigeration cycle apparatus 500 of this modification, both of the advantages of Modification 2 and the advantages of Embodiment 2 can be obtained.

In the second embodiment and the third modification, a preliminary operation similar to that in the first embodiment may be performed. That is, when starting the refrigeration cycle apparatus 400 (or 500), the on-off valve 420 is controlled so that the volume control path 111 is connected to the low pressure introduction path 116. The on-off valve 420 may be controlled so as to be disconnected from the introduction path 116. That is, the opening / closing valve 420 is opened at the time of activation. Further, when the operation of the refrigeration cycle apparatus 400 (or 500) is stopped, the on-off valve 420 may be controlled so as to connect the volume control path 111 to the low pressure introduction path 116. That is, the operation of the refrigeration cycle apparatus 400 (or 500) may be stopped in a state where the on-off valve 420 is opened and the volume control path 111 is connected to the low pressure introduction path 116.

The refrigeration cycle apparatus of the present invention is useful for air conditioners, refrigerators, heaters, water heaters, and the like.

Claims

A compression chamber, a bypass discharge port that opens to the compression chamber, and a bypass discharge valve that opens and closes the bypass discharge port, and the refrigerant sucked into the compression chamber maintains the suction pressure while the bypass discharge port. A volume control compressor configured to be able to change a suction volume by being discharged from the compression chamber through an outlet;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the compression chamber;
A discharge path for guiding the compressed refrigerant from the compression chamber to the radiator;
A volume control path connected to the bypass discharge port;
A flow path switching unit that supplies either the discharge pressure of the compressor or the suction pressure of the compressor to the volume control path as a control pressure;
A high-pressure introduction path having one end connected to the flow path switching unit and the other end connected to the discharge path;
A low-pressure introduction path having one end connected to the flow path switching unit and the other end connected to the suction path;
When the load of the refrigeration cycle apparatus is small, the flow path switching unit is controlled so that the volume control path is connected to the low pressure introduction path. When the load is large, the volume control path is A control device for controlling the flow path switching unit to be connected to the high-pressure introduction path;
A check valve provided in the high-pressure introduction path, allowing a refrigerant flow from the discharge path to the flow path switching unit, and prohibiting a reverse flow;
A refrigeration cycle apparatus comprising:
The compressor further has a suction port and a discharge port;
When the load is small, a part of the refrigerant sucked into the compression chamber from the suction port is discharged from the compression chamber through the bypass discharge port while maintaining the suction pressure, and from the suction port to the compression chamber The refrigeration cycle apparatus according to claim 1, wherein a remaining portion of the refrigerant sucked in is compressed in the compression chamber and discharged from the compression chamber through the discharge port.
A relief valve circuit,
The high-pressure introduction path has a first part between the check valve and the flow path switching unit, and a second part between the check valve and the discharge path,
The refrigeration cycle apparatus according to claim 1, wherein the relief valve circuit has one end connected to the first portion and the other end connected to the second portion or the discharge path.
The compressor includes a first compression chamber and a second compression chamber as the compression chamber, and an internal space that can hold the refrigerant compressed in the first compression chamber and the refrigerant compressed in the second compression chamber. A sealed container, an intermediate chamber that receives the refrigerant discharged from the first compression chamber through the bypass discharge port, a first discharge port that communicates the intermediate chamber and the internal space of the sealed container, and the first discharge port. A hermetic multi-cylinder compressor further having a first discharge valve that opens and closes the outlet;
The volume control path is connected to the bypass discharge port via the intermediate chamber,
When the load is small, the refrigerant sucked into the first compression chamber is discharged from the first compression chamber through the bypass discharge port while maintaining the suction pressure, and the intermediate chamber, the volume control path, and the Returned to the inhalation route through the low pressure introduction route,
When the load is large, the refrigerant sucked into the first compression chamber is compressed to a pressure exceeding the discharge pressure in the first compression chamber, pushes open the bypass discharge valve and the first discharge valve, 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is discharged from the first compression chamber to the internal space of the sealed container through a bypass discharge port, the intermediate chamber, and the first discharge port.
The control device controls the flow path switching unit so that the volume control path is connected to the low pressure introduction path at the time of starting the refrigeration cycle apparatus, and then the volume control path is switched after an arbitrary time has elapsed. The refrigeration cycle apparatus according to claim 1, wherein the flow path switching unit is controlled to be connected to the high-pressure introduction path.
The refrigeration cycle apparatus according to claim 1, wherein when the operation of the refrigeration cycle apparatus is stopped, the control apparatus controls the flow path switching unit so as to connect the volume control path to the low pressure introduction path.
A compression chamber, a bypass discharge port that opens to the compression chamber, and a bypass discharge valve that opens and closes the bypass discharge port, and the refrigerant sucked into the compression chamber maintains the suction pressure while the bypass discharge port. A volume control compressor configured to be able to change a suction volume by being discharged from the compression chamber through an outlet;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the compression chamber;
A discharge path for guiding the compressed refrigerant from the compression chamber to the radiator;
A volume control path connected to the bypass discharge port;
A low-pressure introduction path connected to the suction path;
An on-off valve provided to connect the low-pressure introduction path and the volume control path;
When the load of the refrigeration cycle apparatus is small, the on-off valve is controlled to connect the volume control path to the low pressure introduction path, and when the load is large, the volume control path is changed to the low pressure introduction path. A control device for controlling the on-off valve so as to be separated from
A relief valve circuit having one end connected to the volume control path and the other end connected to the discharge path;
A refrigeration cycle apparatus comprising:
A first compression chamber; a second compression chamber; a sealed container including an internal space capable of holding the refrigerant compressed in the first compression chamber and the refrigerant compressed in the second compression chamber; and the first compression chamber A bypass discharge opening that opens to the opening, a bypass discharge valve that opens and closes the bypass discharge opening, an intermediate chamber that receives the refrigerant discharged from the first compression chamber through the bypass discharge opening, the intermediate chamber, and the sealed container A volume control compressor having a first discharge port that communicates with the internal space, and a first discharge valve that opens and closes the first discharge port;
A radiator for cooling the refrigerant compressed by the compressor;
An expansion mechanism for expanding the refrigerant cooled by the radiator;
An evaporator for heating the refrigerant expanded by the expansion mechanism;
A suction path for leading the refrigerant to be compressed from the evaporator to the first compression chamber and the second compression chamber;
A discharge path for guiding the compressed refrigerant from the first compression chamber and the second compression chamber to the radiator;
A volume control path connected to the bypass outlet through the intermediate chamber;
A low-pressure introduction path connected to the suction path;
An on-off valve provided to connect the low-pressure introduction path and the volume control path;
(I) When the load of the refrigeration cycle apparatus is small, the volume control path is connected to the low pressure introduction path, so that the refrigerant sucked into the first compression chamber maintains the suction pressure and the bypass Controlling the on-off valve so that it is discharged from the first compression chamber through the discharge port and returned to the suction passage through the intermediate chamber, the volume control path, and the low pressure introduction path; and (ii) when the load is large By separating the volume control path from the low-pressure introduction path, the refrigerant sucked into the first compression chamber is compressed to a pressure exceeding the discharge pressure of the compressor in the first compression chamber, and the bypass discharge valve And the first discharge valve is pushed open and discharged from the first compression chamber to the internal space of the sealed container through the bypass discharge port, the intermediate chamber, and the first discharge port. A control device for controlling the opening and closing valve so,
A refrigeration cycle apparatus comprising:
The control device controls the on-off valve so that the volume control path is connected to the low pressure introduction path when the refrigeration cycle apparatus is started up. The refrigeration cycle apparatus according to claim 7, wherein the on-off valve is controlled so as to be separated from the introduction path.
The refrigeration cycle apparatus according to claim 7, wherein when the operation of the refrigeration cycle apparatus is stopped, the control apparatus controls the on-off valve so as to connect the volume control path to the low pressure introduction path.