JP7367222B2 - Refrigeration cycle equipment - Google Patents

Description

The present disclosure relates to a refrigeration cycle device.

JP 2017-26238 A (Patent Document 1) describes a refrigerant circuit in which refrigerant circulates through a compressor, a condenser, a subcooler, an expansion valve, and an evaporator, and a refrigerant circuit in which refrigerant is condensed in a condenser. A refrigeration cycle device is disclosed that includes an injection circuit that returns to the compressor. This injection circuit switches between gas injection in which the refrigerant flowing through the injection circuit is evaporated in a supercooler and then returned to the compressor, and liquid injection in which the refrigerant flowing in the injection circuit is returned to the compressor without passing through the supercooler. Contains flow path switching means.

The compressor includes a low pressure side compression section, an intermediate pressure chamber, and a high pressure side compression section. The low pressure side compression section sucks in and adiabatically compresses the refrigerant evaporated in the evaporator, and discharges the refrigerant to the intermediate pressure chamber. The high pressure side compression section sucks in and adiabatically compresses the refrigerant in the intermediate pressure chamber, and discharges the refrigerant to the condenser.

JP2017-26238A

In the process where the refrigerant is adiabatically compressed in the compressor, the refrigerant pressure P, the refrigerant volume V, the refrigerant temperature T, and the refrigerant specific heat ratio γ satisfy the following relational expressions (1) and relational expressions (2). .

Therefore, for example, when a refrigerant with a high specific heat ratio γ, such as a refrigerant containing carbon dioxide (CO ₂ ), is filled into a refrigeration cycle device equipped with an intermediate pressure injection flow path as described above, the specific heat ratio γ is relatively The temperature Td (discharge temperature) of the refrigerant when discharged from the compressor tends to rise compared to when the refrigeration cycle device is filled with a refrigerant with a low temperature. The flow rate of refrigerant returned to the compressor from the injection circuit (injection flow rate) increases.

On the other hand, when a refrigerant with a high specific heat ratio γ is filled into a refrigeration cycle device equipped with an intermediate pressure injection flow path as described above, a refrigerant with a relatively low specific heat ratio γ is filled into the refrigeration cycle device. The pressure of the refrigerant returned to the compressor from the injection circuit (intermediate pressure) is likely to rise compared to the case where the high pressure refrigerant discharged from the compressor and the intermediate pressure refrigerant returned to the compressor from the injection circuit are Pressure difference becomes smaller. That is, in the former case, compared to the latter case, it is difficult to obtain the injection flow rate required to suppress the rise in discharge temperature, and it is difficult to reliably suppress the rise in discharge temperature.

A main objective of the present disclosure is to provide a refrigeration cycle device that can reliably suppress an increase in discharge temperature even with a refrigerant having a high specific heat ratio.

A refrigeration cycle device according to the present disclosure includes a first refrigerant circuit that includes a compressor, a condenser, a first expansion valve, and an evaporator, and in which refrigerant circulates through the compressor, the condenser, the first expansion valve, and the evaporator in order. Equipped with The compressor has a discharge port for discharging refrigerant at a first pressure, a suction port for inhaling refrigerant at a second pressure lower than the first pressure, and a refrigerant at an intermediate pressure between the first pressure and the second pressure. and an intermediate pressure port for inflow. The refrigeration cycle device has a first end connected between a condenser and a first expansion valve in a first refrigerant circuit, and a second end connected to an intermediate pressure port of a compressor. The compressor further includes an intermediate pressure injection flow path for returning a portion of the refrigerant that has flowed out of the container to the compressor. The intermediate pressure injection flow path includes a second expansion valve, a bypass flow path that bypasses the second expansion valve, and an adjustment valve that adjusts the flow rate of the refrigerant flowing through the bypass flow path.

According to the present disclosure, it is possible to provide a refrigeration cycle device that can reliably suppress an increase in discharge temperature even with a refrigerant having a high specific heat ratio.

1 is a block diagram showing a refrigeration cycle device according to Embodiment 1. FIG. FIG. 2 is a block diagram showing a refrigeration cycle device according to a second embodiment. It is a block diagram showing the 1st modification of the refrigeration cycle device concerning Embodiment 2. It is a block diagram showing the 2nd modification of the refrigeration cycle device concerning Embodiment 2. It is a block diagram showing the 3rd modification of the refrigeration cycle device concerning Embodiment 2. FIG. 3 is a block diagram showing a refrigeration cycle device according to a third embodiment. It is a block diagram showing the 1st modification of the refrigeration cycle device concerning Embodiment 3. It is a block diagram showing the 2nd modification of the refrigeration cycle device concerning Embodiment 3. It is a block diagram showing the 3rd modification of the refrigeration cycle device concerning Embodiment 3. FIG. 3 is a block diagram showing a refrigeration cycle device according to a fourth embodiment. It is a block diagram showing the 1st modification of the refrigeration cycle device concerning Embodiment 4. It is a block diagram showing the 2nd modification of the refrigeration cycle device concerning Embodiment 4. It is a block diagram showing the 3rd modification of the refrigeration cycle device concerning Embodiment 4.

The present embodiment will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals and the description thereof will not be repeated.

Embodiment 1.
As shown in FIG. 1, the refrigeration cycle device 100 according to the first embodiment includes a first refrigerant circuit and an intermediate pressure injection flow path 13. The first refrigerant circuit and intermediate pressure injection flow path 13 are filled with a first refrigerant (hereinafter simply referred to as refrigerant). The refrigerant may be any refrigerant. The refrigeration cycle device 100 is suitable for refrigerants with a high specific heat ratio. The specific heat ratio of the refrigerant is, for example, 1.16 or more. The refrigerant includes, for example, at least one selected from the group consisting of CO ₂ , ammonia (NH ₃ ), R32, R434A, R410A, and R407H.

The first refrigerant circuit includes a compressor 1 , a condenser 2 , a first expansion valve 3 , and an evaporator 4 . The first refrigerant circulates through the compressor 1, condenser 2, first expansion valve 3, and evaporator 4 in this order.

The compressor 1 has a discharge port that discharges refrigerant at a first pressure, a suction port that sucks refrigerant at a second pressure lower than the first pressure, and an intermediate pressure between the first pressure and the second pressure. It has an intermediate pressure port into which refrigerant is injected. The discharge port is connected to the refrigerant inlet of the condenser 2 . The suction port is connected to the refrigerant outlet of the evaporator 4. The intermediate pressure port is connected to a second end of the intermediate pressure injection channel 13, which will be described later.

The compressor 1 is, for example, a multistage compressor. The compressor 1 has a high pressure side compression section connected to a discharge port, a low pressure side compression section connected to an intake port, and an intermediate pressure port, and connects the high pressure side compression section and the low pressure side compression section. and an intermediate pressure chamber. In the low pressure side compression section, the second pressure refrigerant sucked from the suction port is adiabatically compressed to become intermediate pressure refrigerant, and is discharged into the intermediate pressure chamber. In the high pressure side compression section, the intermediate pressure refrigerant sucked from the intermediate pressure chamber is adiabatically compressed to become a first pressure refrigerant, and is discharged to the outside of the compressor 1 from the discharge port.

In the condenser 2, the refrigerant discharged from the discharge port of the compressor 1 is condensed. The condenser 2 has a refrigerant inflow section into which the refrigerant flows, a heat exchange section through which the refrigerant exchanges heat with a heat medium such as air, and a refrigerant outflow section through which the refrigerant flows out.

In the first expansion valve 3, the refrigerant condensed in the condenser 2 is adiabatically expanded. The first expansion valve 3 is, for example, an electronic expansion valve. In the evaporator 4, the refrigerant whose pressure has been reduced by the first expansion valve 3 is evaporated. The evaporator 4 has a refrigerant inflow section into which the refrigerant flows, a heat exchange section through which the refrigerant exchanges heat with a heat medium such as air, and a refrigerant outflow section through which the refrigerant flows out. The refrigerant evaporated in the evaporator 4 is sucked into the suction port of the compressor 1.

In the first refrigerant circuit, the refrigerant flow path that connects the refrigerant outlet of the condenser 2 and the first expansion valve 3 is called a first flow path 10, and the refrigerant flow path that connects the refrigerant outlet of the condenser 2 and the first expansion valve 3 is called a first flow path 10, and the refrigerant flow path that connects the refrigerant outlet of the condenser 2 and the first expansion valve 3 is called a first flow path 10. The connecting flow path is called a second flow path 11, and the flow path connecting the refrigerant outlet of the evaporator 4 and the suction port of the compressor 1 is called a third flow path 12.

In the first refrigerant circuit, for example, the condenser 2 is a heat source side heat exchanger, and the evaporator 4 is a load side heat exchanger. In this case, the compressor 1, the condenser 2, the first expansion valve 3, the second expansion valve 5, the first passage 10, the intermediate pressure injection passage 13, the bypass passage 14, the regulating valve 15, and the second A portion of each of the passage 11 and the third flow passage 12 is arranged within the heat source side unit (outdoor unit). The evaporator 4 and other parts of each of the second flow path 11 and the third flow path 12 are arranged within the load side unit (indoor unit). The remainder of each of the second flow path 11 and the third flow path 12 is arranged in piping that connects the heat source side unit and the load side unit.

The intermediate pressure injection flow path 13 includes a second expansion valve 5 , a bypass flow path 14 that bypasses the second expansion valve, and an adjustment valve 15 that adjusts the flow rate of the refrigerant flowing through the bypass flow path 14 . A first end of the intermediate pressure injection flow path 13 is connected to the first flow path 10 of the first refrigerant circuit. A second end of the intermediate pressure injection channel 13 is connected to an intermediate pressure port of the compressor. The intermediate pressure injection flow path 13 returns a portion of the refrigerant condensed in the condenser 2 to the compressor 1 when the opening degree of the second expansion valve 5 is greater than zero.

In the second expansion valve 5, the refrigerant flowing through the intermediate pressure injection flow path 13 is adiabatically expanded. The second expansion valve 5 is, for example, an electronic expansion valve. The opening degree of the second expansion valve 5 is controlled by a control unit 210, which will be described later, and increases or decreases. The flow rate of the refrigerant flowing through the intermediate pressure injection channel 13 increases or decreases depending on the opening degree of the second expansion valve 5. When the opening degree of the second expansion valve 5 is zero, that is, when the second expansion valve 5 is closed, all the refrigerant condensed in the condenser 2 flows into the first expansion valve 3, and the refrigerant is at an intermediate pressure. It does not flow into the injection channel 13. When the opening degree of the second expansion valve 5 is greater than zero, a portion of the refrigerant condensed in the condenser 2 flows through the intermediate pressure injection flow path 13 .

One end of the bypass passage 14 is connected to a portion of the intermediate pressure injection passage 13 located upstream of the second expansion valve 5 . The other end of the bypass flow path 14 is connected to a portion of the intermediate pressure injection flow path 13 located downstream of the second expansion valve 5 .

The regulating valve 15 may have any configuration as long as it can regulate the flow rate of the refrigerant flowing through the bypass channel 14, and is, for example, an on-off valve, and a more specific example is a solenoid valve. The opening degree of the regulating valve 15 when the temperature of the high-pressure refrigerant discharged from the discharge port is higher than the determination value is the same as the opening degree of the regulating valve 15 when the temperature of the high-pressure refrigerant discharged from the discharge port is below the determination value. It is high compared to the opening degree.

The refrigeration cycle device 100 includes a temperature sensor 200 that measures the temperature of the refrigerant discharged from the compressor 1 (discharge temperature), and a control section that controls the opening degrees of the second expansion valve 5 and the adjustment valve 15 according to the discharge temperature. 210. Temperature sensor 200 is, for example, a thermistor.

The control unit 210 includes a CPU (Central Processing Unit) not shown, memories (ROM (Read Only Memory) and RAM (Random Access Memory) not shown), and input/output buffers (not shown) for inputting and outputting various signals. It consists of: The CPU expands the program stored in the ROM to a RAM or the like and executes the program. The program stored in the ROM is a program in which the processing procedure of the control unit 210 is written. The control unit 210 controls the second expansion valve 5 and the adjustment valve 15 according to these programs. Note that the above control is not limited to processing by software, and can also be performed by dedicated hardware (electronic circuit).

Control unit 210 determines whether the discharge temperature measured by temperature sensor 200 is below a determination value. The control unit 210 keeps the second expansion valve 5 and the adjustment valve 15 closed while the discharge temperature is below the determination value. The control unit 210 opens the second expansion valve 5 when the discharge temperature becomes higher than the determination value. If the discharge temperature is still higher than the determination value even when the second expansion valve 5 is fully opened, the control unit 210 opens the adjustment valve 15. The control unit 210 keeps the second expansion valve 5 and the adjustment valve 15 open while the discharge temperature is higher than the determination value.

The control unit 210 closes the second expansion valve 5 when the discharge temperature becomes equal to or lower than the determination value again. The control unit 210 makes the above determination continuously or intermittently while the refrigeration cycle device 100 is operating.

In addition, when the discharge temperature becomes higher than the determination value, the control unit 210 may open at least one of the second expansion valve 5 and the adjustment valve 15, and may open the second expansion valve 5 and the adjustment valve 15 at the same time. It's okay.

The effects of the refrigeration cycle device 100 will be explained based on comparison with a refrigeration cycle device according to a comparative example. The refrigeration cycle device according to Comparative Example 1 differs from the refrigeration cycle device 100 only in that the injection flow path does not include the bypass flow path 14 and the regulating valve 15. The refrigeration cycle device according to Comparative Example 2 differs from the refrigeration cycle device 100 in that it does not include the injection flow path, the second expansion valve included therein, the bypass flow path 14, and the adjustment valve 15.

Also in the refrigeration cycle device according to Comparative Example 1, when the discharge temperature becomes higher than the determination value, the second expansion valve is opened. Thereby, a part of the refrigerant condensed in the condenser flows into the injection flow path. The refrigerant that has flowed into the injection flow path undergoes adiabatic expansion and pressure reduction at the second expansion valve, and becomes intermediate-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is injected into the intermediate pressure chamber from the intermediate pressure port of the compressor 1 .

In the refrigeration cycle device according to Comparative Example 1, when the refrigerant having a high specific heat ratio is filled, it is difficult to suppress the discharge temperature to below the determination value even if the second expansion valve is fully opened. For example, when the specific heat ratio of the refrigerant is 1.16 or more, when the refrigeration cycle device according to Comparative Example 1 is operated, the evaporation temperature may be -10°C, the condensation temperature may be 45°C, and the suction superheat may be 10K. Under these operating conditions, the discharge temperature exceeds 100°C. Therefore, when the determination value is 100° C. as described above, it is difficult to suppress the discharge temperature below the determination value even if the second expansion valve is fully opened.

In contrast, in the refrigeration cycle device 100, the intermediate pressure injection flow path 13 includes a bypass flow path 14 and a regulating valve 15. Therefore, when comparing the refrigeration cycle apparatus 100 in which the opening degree of the second expansion valve 5 is the same and the refrigeration cycle apparatus according to Comparative Example 1, it is found that the intermediate pressure of the refrigeration cycle apparatus 100 when the regulating valve 15 is further opened is The flow rate of the refrigerant flowing through the injection flow path 13 is greater than the flow rate of the refrigerant flowing through the intermediate pressure injection flow path of the refrigeration cycle device according to Comparative Example 1. Therefore, compared to the refrigeration cycle apparatus according to Comparative Example 1, the refrigeration cycle apparatus 100 can reliably suppress an increase in discharge temperature even in the case of a refrigerant having a high specific heat ratio.

Furthermore, in the refrigeration cycle device 100, compared to the refrigeration cycle device according to Comparative Example 1, the time for flowing the refrigerant through the intermediate pressure injection flow path 13 can be shortened in order to suppress a rise in discharge temperature. That is, in the refrigeration cycle device 100, compared to the refrigeration cycle device according to Comparative Example 1, the time from when an increase in discharge temperature is detected until normal operation is resumed can be shortened. Therefore, in the refrigeration cycle device 100, as compared to the refrigeration cycle device according to Comparative Example 1, the decrease in capacity caused by the process of suppressing the rise in discharge temperature is suppressed.

Furthermore, in the refrigeration cycle device according to Comparative Example 2, a so-called liquid back state is realized in which liquid phase refrigerant is sucked into the compressor in order to suppress an increase in discharge temperature. In the refrigeration cycle device according to Comparative Example 2, the higher the specific heat ratio of the filled refrigerant, the greater the flow rate of the liquid phase refrigerant to be sucked into the compressor in the liquid back state. If a large amount of liquid phase refrigerant is returned to the compressor, the oil in the compressor will be diluted and the reliability of the compressor will be compromised.

On the other hand, in the refrigeration cycle apparatus 100, the rise in discharge temperature can be suppressed without realizing a so-called liquid back state. Therefore, in the refrigeration cycle device 100, the reliability of the compressor 1 is higher than that of the refrigeration cycle device according to the second comparative example.

Note that the first refrigerant circuit may include a switching unit, such as a four-way valve, that switches the refrigerant flow direction. In such a refrigeration cycle device 100, the switching unit allows a cooling operation in which the heat source side heat exchanger acts as a condenser and a load side heat exchanger as an evaporator, and a cooling operation in which the heat source side heat exchanger acts as an evaporator. The heating operation in which the load-side heat exchanger acts as a condenser is switched.

Embodiment 2.
As shown in FIG. 2, the refrigeration cycle device 101 according to the second embodiment has basically the same configuration as the refrigeration cycle device 100 according to the first embodiment, but the intermediate pressure injection flow path 13 is It differs from the refrigeration cycle device 100 in that it further includes a cooling section 6. Note that in FIG. 2, illustration of the temperature sensor 200 and the control unit 210 is omitted.

In the first cooling unit 6, the refrigerant whose pressure has been reduced by the second expansion valve 5 is cooled. The first cooling unit 6 is arranged between the second expansion valve 5 and the intermediate pressure port of the compressor 1 in the intermediate pressure injection flow path 13 . Preferably, the first cooling unit 6 is disposed in the intermediate pressure injection passage 13 between the other end of the bypass passage 14 and the intermediate pressure port of the compressor 1 . In other words, the other end of the bypass flow path 14 is connected to a portion of the intermediate pressure injection flow path 13 that is located downstream of the second expansion valve 5 and upstream of the first cooling section 6. . Note that the other end of the bypass flow path 14 may be connected to a portion of the intermediate pressure injection flow path 13 located downstream of the first cooling section 6 .

The first cooling section 6 has a refrigerant inflow section into which the refrigerant flows, a heat exchange section through which the refrigerant exchanges heat with a cold source such as air, and a refrigerant outflow section through which the refrigerant flows out. By cooling the refrigerant in the first cooling section 6, the dryness of the refrigerant decreases. The refrigerant cooled in the first cooling section 6 is sucked into the intermediate pressure port of the compressor 1 .

Since the refrigeration cycle device 101 also includes the intermediate pressure injection channel 13 including the bypass channel 14 and the regulating valve 15, it can achieve the same effects as the refrigeration cycle device 100.

Furthermore, in the refrigeration cycle device 101, the intermediate pressure injection flow path 13 includes the first cooling section 6. In the refrigeration cycle device 101 as well, when the discharge temperature becomes higher than the determination value, the second expansion valve 5 is opened. As a result, a part of the refrigerant condensed in the condenser 2 flows into the intermediate pressure injection flow path 13 . The refrigerant flowing into the intermediate pressure injection flow path 13 is adiabatically expanded and depressurized by the second expansion valve 5, and becomes an intermediate pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is cooled by a cold source in the first cooling unit 6, and becomes a low-temperature gas-liquid two-phase refrigerant. The low temperature gas-liquid two-phase refrigerant is injected into the intermediate pressure chamber from the intermediate pressure port of the compressor 1 .

Therefore, the temperature of the refrigerant injected into the intermediate pressure chamber from the intermediate pressure port of the compressor 1 in the refrigeration cycle device 101 is lower than the temperature of the refrigerant injected into the intermediate pressure chamber from the intermediate pressure port of the compressor in the refrigeration cycle device 100. It also becomes lower. Therefore, in the refrigeration cycle device 101, compared to the refrigeration cycle device 100, an increase in the discharge temperature can be suppressed even when the flow rate of the refrigerant in the intermediate pressure injection flow path 13 is not small. That is, in the refrigeration cycle device 101, even when the specific heat ratio of the refrigerant filled is high, the increase in discharge temperature can be suppressed compared to the refrigeration cycle device 100.

(Modified example)
3 to 5 are block diagrams showing first to third modifications of the refrigeration cycle device 101 shown in FIG. 2. Note that in FIGS. 3 to 5, illustrations of the temperature sensor 200 and the control unit 210 are omitted.

The refrigeration cycle device 102 shown in FIG. 3 has basically the same configuration as the refrigeration cycle device 101, but further includes a second refrigerant circuit 20 in which a second refrigerant circulates, and cools the refrigerant in the first cooling section 6. It differs from the refrigeration cycle device 101 in that the source is the second refrigerant.

The second refrigerant may be any refrigerant. The specific heat ratio of the second refrigerant is lower than that of the first refrigerant, for example. The specific heat ratio of the second refrigerant may be equal to the specific heat ratio of the first refrigerant, for example.

The second refrigerant circuit 20 includes a second compressor 21 , a second condenser 22 , a third expansion valve 23 , and a first cooling section 6 . The second refrigerant circulates through the second compressor 21, the second condenser 22, the third expansion valve 23, and the first cooling section 6 in this order. In the first cooling unit 6, the second refrigerant flowing through the second refrigerant circuit 20 absorbs the heat of vaporization from the refrigerant flowing through the intermediate pressure injection flow path 13 and evaporates. Thereby, the first cooling unit 6 cools the refrigerant flowing through the intermediate pressure injection flow path 13 with the second refrigerant flowing through the second refrigerant circuit 20 . The operating conditions of the second compressor 21 and the third expansion valve 23 are set so that the second refrigerant flowing through the first cooling section 6 can sufficiently cool the refrigerant flowing through the intermediate pressure injection flow path 13.

As described above, the refrigeration cycle device 102 also has the bypass flow path 14, the regulating valve 15, and the intermediate pressure injection flow path 13 including the first cooling section 6, so it has the same effect as the refrigeration cycle device 101. be able to.

The refrigeration cycle device 103 shown in FIG. 4 has basically the same configuration as the refrigeration cycle device 101, but the first cooling section 6 is an internal heat exchanger, and the first cooling section 6 has an intermediate pressure injection flow. This differs from the refrigeration cycle device 101 in that the cold source for the refrigerant flowing through the path 13 is the refrigerant flowing between the first expansion valve 3 and the suction port of the compressor 1.

In the first cooling section 6 shown in FIG. 4, the refrigerant flowing through the intermediate pressure injection flow path 13 exchanges heat with the refrigerant flowing through the second flow path 11. In the refrigeration cycle device 103, the second expansion valve 5 is opened when the discharge temperature is higher than the determination value. At this time, the opening degree of the second expansion valve 5 is set so that the amount of pressure drop of the refrigerant at the second expansion valve 5 is smaller than the amount of pressure drop of the refrigerant at the first expansion valve 3. For example, the second expansion valve 5 is fully opened. As a result, the flow rate of the refrigerant flowing through the second expansion valve 5 is maximized, and the temperature of the refrigerant expanded adiabatically in the second expansion valve 5 is higher than the temperature of the refrigerant expanded adiabatically in the first expansion valve 3. Become. Therefore, in the first cooling unit 6 , a relatively large amount of refrigerant flowing through the intermediate pressure injection flow path 13 is cooled by the refrigerant flowing through the second flow path 11 .

As described above, the refrigeration cycle device 103 also has the bypass flow path 14, the regulating valve 15, and the intermediate pressure injection flow path 13 including the first cooling section 6, so it has the same effect as the refrigeration cycle device 101. be able to.

The refrigeration cycle device 104 shown in FIG. 5 has basically the same configuration as the refrigeration cycle device 103, but the cold heat source for the refrigerant flowing through the intermediate pressure injection channel 13 in the first cooling section 6 is the same as the evaporator 4. It differs from the refrigeration cycle device 103 in that the refrigerant flows between the suction port of the compressor 1 and the refrigerant.

In the first cooling section 6 shown in FIG. 5, the refrigerant flowing through the intermediate pressure injection flow path 13 exchanges heat with the refrigerant flowing through the third flow path 12. In the refrigeration cycle device 104, the second expansion valve 5 is opened when the discharge temperature is higher than the determination value. For example, the second expansion valve 5 is fully opened. Thereby, the flow rate of the refrigerant flowing through the second expansion valve 5 is maximized. The temperature of the refrigerant expanded adiabatically in the second expansion valve 5 is higher than the temperature of the refrigerant expanded adiabatically in the first expansion valve 3 and evaporated in the evaporator 4. Therefore, in the first cooling unit 6 , a relatively large amount of refrigerant flowing through the intermediate pressure injection flow path 13 is cooled by the refrigerant flowing through the third flow path 12 .

As described above, the refrigeration cycle device 104 also has the bypass flow path 14, the regulating valve 15, and the intermediate pressure injection flow path 13 including the first cooling section 6, so it has the same effect as the refrigeration cycle device 101. be able to.

Embodiment 3.
As shown in FIG. 6, the refrigeration cycle device 105 according to the third embodiment has basically the same configuration as the refrigeration cycle device 100 according to the first embodiment, but the refrigerant circuit connects the second cooling unit 7. It differs from the refrigeration cycle device 100 in that it further includes the following.

The second cooling unit 7 cools the refrigerant flowing between the condenser 2 and the first end of the intermediate pressure injection flow path 13 in the first flow path 10 using a second cold source. In the second cooling section 7, the refrigerant condensed in the condenser 2 is supercooled. The second cooling section 7 acts as a supercooler. The second cooling unit 7 is arranged between the condenser 2 and the first end of the intermediate pressure injection flow path 13 in the refrigerant circuit. The second cooling section 7 has a refrigerant inflow section into which the refrigerant flows, a heat exchange section through which the refrigerant exchanges heat with a second cold source such as air, and a refrigerant outflow section through which the refrigerant flows out.

When the opening degree of the second expansion valve 5 is zero, that is, when the second expansion valve 5 is closed, all the refrigerant condensed in the condenser 2 and supercooled in the second cooling section 7 is transferred to the first Flowing into the expansion valve 3, the refrigerant does not flow into the intermediate pressure injection channel 13. When the opening degree of the second expansion valve 5 is greater than zero, a part of the refrigerant that has been condensed in the condenser 2 and supercooled in the second cooling section 7 flows through the intermediate pressure injection flow path 13 .

Since the refrigeration cycle device 105 includes the intermediate pressure injection flow path 13 including the bypass flow path 14 and the regulating valve 15, it can achieve the same effects as the refrigeration cycle device 100.

Furthermore, in the refrigeration cycle device 105, since the refrigerant circuit includes the second cooling unit 7, the degree of subcooling of the refrigerant flowing into the first expansion valve 3 is higher than that in the refrigeration cycle device 100. As a result, the performance of the refrigeration cycle device 105 is higher than that of the refrigeration cycle device 100.

(Modified example)
7 to 9 are block diagrams showing first to third modifications of the refrigeration cycle device 105 shown in FIG. 6. Note that in FIGS. 7 to 9, illustrations of the temperature sensor 200 and the control unit 210 are omitted.

The refrigeration cycle apparatus 106 shown in FIG. This differs from the refrigeration cycle device 105 in that the cold source (second cold source) for the refrigerant flowing through the path 10 is a third refrigerant.

The third refrigerant circuit 30 includes a third compressor 31 , a third condenser 32 , a fourth expansion valve 33 , and a second cooling section 7 . The third refrigerant circulates through the third compressor 31, the third condenser 32, the fourth expansion valve 33, and the second cooling unit 7 in this order. In the second cooling unit 7, the third refrigerant flowing through the third refrigerant circuit 30 absorbs the heat of vaporization from the refrigerant flowing through the first flow path 10 and evaporates. Thereby, the second cooling unit 7 cools the refrigerant flowing through the first channel 10 with the third refrigerant flowing through the third refrigerant circuit 30 . The operating conditions of the third compressor 31 and the fourth expansion valve 33 are set so that the third refrigerant flowing through the second cooling section 7 can sufficiently cool the refrigerant flowing through the first flow path 10. The third refrigerant may be any refrigerant. The specific heat ratio of the third refrigerant is lower than that of the first refrigerant, for example. The specific heat ratio of the third refrigerant may be equal to the specific heat ratio of the first refrigerant, for example.

The refrigeration cycle device 107 shown in FIG. 8 has basically the same configuration as the refrigeration cycle device 105, but the cold source for the refrigerant flowing through the first flow path 10 in the second cooling unit 7 is the first expansion valve 3. It differs from the refrigeration cycle device 105 in that the refrigerant flows between the refrigerant and the suction port of the compressor 1. In the second cooling section 7 , the refrigerant flowing through the first flow path 10 exchanges heat with the refrigerant flowing through the second flow path 11 .

The refrigeration cycle apparatus 108 shown in FIG. It differs from the refrigeration cycle device 103 in that the refrigerant flows between the refrigerant and the suction port of the machine 1. In the second cooling section 7 , the refrigerant flowing through the first flow path 10 exchanges heat with the refrigerant flowing through the third flow path 12 .

The refrigeration cycle devices 106, 107, and 108 shown in FIGS. 7 to 9 can have the same effect as the refrigeration cycle device 105 because the refrigerant circuit further includes the second cooling section 7.

Embodiment 4.
As shown in FIG. 10, a refrigeration cycle device 109 according to the fourth embodiment has basically the same configuration as the refrigeration cycle device 100 according to the first embodiment, but the intermediate pressure injection flow path 13 is It differs from the refrigeration cycle device 100 in that it further includes a cooling section 6 and the refrigerant circuit further includes a second cooling section 7.

The first cooling unit 6 of the refrigeration cycle device 109 has the same configuration as the first cooling unit 6 of the refrigeration cycle device 101 shown in FIG. 2. The second cooling unit 7 of the refrigeration cycle device 109 has the same configuration as the second cooling unit 7 of the refrigeration cycle device 105 shown in FIG.

Since the refrigeration cycle device 109 includes the intermediate pressure injection flow path 13 including the bypass flow path 14 and the regulating valve 15, it can achieve the same effects as the refrigeration cycle device 100.

Furthermore, since the refrigeration cycle device 109 further includes the first cooling section 6 shown in FIG. 2 and the second cooling section 7 shown in FIG. can be played at the same time.

(Modified example)
11 to 13 are block diagrams showing first to third modifications of the refrigeration cycle device 109 shown in FIG. 10. Note that illustration of the temperature sensor 200 and the control unit 210 is omitted in FIGS. 11 to 13.

The refrigeration cycle device 110 shown in FIG. 11 has basically the same configuration as the refrigeration cycle device 109, but the first cooling unit 6 has the same configuration as the first cooling unit 6 shown in FIG. 3. This differs from the refrigeration cycle device 109 in this point.

The refrigeration cycle device 111 shown in FIG. 12 has basically the same configuration as the refrigeration cycle device 109, but the first cooling unit 6 has the same configuration as the first cooling unit 6 shown in FIG. It differs from the refrigeration cycle device 109 in that the second cooling unit 7 has the same configuration as the second cooling unit 7 shown in FIG. 7 .

The refrigeration cycle device 112 shown in FIG. 13 has basically the same configuration as the refrigeration cycle device 111, but the first cooling unit 6 has the same configuration as the first cooling unit 6 shown in FIG. This differs from the refrigeration cycle device 109 in this point.

Since the refrigeration cycle devices 110, 111, and 112 shown in FIGS. 11 to 13 are equipped with the first cooling section 6 and the second cooling section 7 at the same time, they can achieve the same effect as the refrigeration cycle device 109. . Note that the second cooling unit 7 of the refrigeration cycle apparatuses 109, 110, 111, and 112 may have the same configuration as any of the second cooling units 7 shown in FIGS. 6 to 9.

Although the embodiments of the present disclosure have been described above, the embodiments described above can be modified in various ways. Further, the scope of the present disclosure is not limited to the above-described embodiments. The scope of the present disclosure is indicated by the claims, and is intended to include meanings equivalent to the claims and all changes within the range.

1 compressor, 2 condenser, 3 first expansion valve, 4 evaporator, 5 second expansion valve, 6 cooling section, 7 second cooling section, 10 first flow path, 11 second flow path, 12 third Channel, 13 Intermediate pressure injection channel, 14 Bypass channel, 15 Regulating valve, 20 Second refrigerant circuit, 21 Second compressor, 22 Second condenser, 23 Third expansion valve, 30 Third refrigerant circuit, 31 3rd compressor, 32 3rd condenser, 33 4th expansion valve, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112 refrigeration cycle device, 200 temperature sensor, 210 Control unit.

Claims (9)

a first refrigerant circuit including a compressor, a condenser, a first expansion valve, and an evaporator, in which refrigerant circulates through the compressor, the condenser, the first expansion valve, and the evaporator in order;
The compressor has a discharge port that discharges the refrigerant at a first pressure, a suction port that sucks the refrigerant at a second pressure lower than the first pressure, and a space between the first pressure and the second pressure. an intermediate pressure port into which the refrigerant at an intermediate pressure of
a first end connected between the condenser and the first expansion valve in the first refrigerant circuit; and a second end connected to the intermediate pressure port of the compressor; further comprising an intermediate pressure injection flow path for returning a portion of the refrigerant flowing out from the condenser to the compressor,
The intermediate pressure injection flow path includes a second expansion valve, a bypass flow path that bypasses the second expansion valve, an adjustment valve that adjusts the flow rate of the refrigerant flowing through the bypass flow path , and the intermediate pressure injection flow path. a first cooling unit that cools the flowing refrigerant using a cold source ;
One end of the bypass flow path is connected to a portion of the intermediate pressure injection flow path located upstream of the second expansion valve, and the other end of the bypass flow path is connected to a portion of the intermediate pressure injection flow path that is located upstream of the second expansion valve. connected to a portion located downstream of the second expansion valve,
A refrigeration cycle device, wherein the first cooling unit is disposed in the intermediate pressure injection flow path between the other end of the bypass flow path and the intermediate pressure port of the compressor. The opening degree of the regulating valve when the temperature of the high-pressure refrigerant discharged from the discharge port is higher than the determination value is the opening degree of the regulating valve when the temperature of the high-pressure refrigerant discharged from the discharge port is equal to or lower than the determination value. The refrigeration cycle device according to claim 1, wherein the opening degree is higher than the opening degree. The refrigeration cycle device according to claim 1 or 2 , wherein the cold source is the refrigerant flowing between the first expansion valve and the suction port of the compressor in the first refrigerant circuit. The refrigeration cycle device according to claim 3 , wherein the cold source is the refrigerant flowing between the evaporator and the suction port of the compressor in the first refrigerant circuit. The refrigeration cycle device according to claim 1 or 2 , wherein the cold source is air. further comprising a second refrigerant circuit in which a second refrigerant circulates;
The refrigeration cycle device according to claim 1 or 2 , wherein the cold source is the second refrigerant. The first refrigerant circuit further includes a second cooling unit that cools the refrigerant flowing between the condenser and the first end of the intermediate pressure injection flow path using a second cold source. 6. The refrigeration cycle device according to any one of 6 . The refrigeration cycle device according to any one of claims 1 to 7, wherein the refrigerant has a specific heat ratio of 1.16 or more. The refrigeration cycle device according to any one of claims 1 to 8 , wherein the refrigerant contains carbon dioxide.

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