JPWO2011099057A1 - Refrigeration air conditioner - Google Patents

Abstract

A refrigeration air conditioner capable of stably starting an expander is obtained. In the refrigerating and air-conditioning apparatus 100, a main compressor 1, an intercooler 2, a sub compressor 5, a radiator 3, an expander 6, and an evaporator 4 are sequentially connected by piping. The sub compressor 5 is driven by the power collected by the expander 6. The refrigerating and air-conditioning apparatus 100 is provided with a first bypass pipe 9, a first on-off valve 10, a second bypass pipe 11, a second expansion valve 12, a first check valve 13, and a first expansion valve 14. .

Description

  The present invention relates to a refrigeration air conditioner including a sub-compressor driven by power recovered by an expander.

  A conventional refrigeration air conditioner has been proposed that includes a sub-compressor that is driven by power recovered by an expander. As a conventional refrigeration air conditioner equipped with a sub-compressor driven by power recovered by such an expander, for example, “a refrigerant of carbon dioxide is sequentially circulated to a compressor, a radiator, an expansion mechanism, and an evaporator. In a vapor compression refrigeration air conditioner that releases heat from a radiator in a supercritical state, the radiator is composed of a first radiator and a second radiator that are sequentially connected in series, and each of the radiators Another compressor is inserted in between, the drive shaft of the other compressor and the output shaft of the expansion mechanism are linked, and the gas suction port and the gas discharge port of the other compressor are connected, and the other compressor It has a structure in which a bypass pipe that circumvents the path is provided "(for example, see Patent Document 1).

Japanese Patent No. 4031849 (paragraph [0009], FIG. 1)

  However, in the refrigerating and air-conditioning apparatus configured as in Patent Document 1, the refrigerant flowing into the discharge side of the sub-compressor is in a state after passing through the bypass pipe in a state before the expander is started. Become. For this reason, a pressure difference corresponding to the pressure loss generated when the refrigerant passes through the bypass pipe is generated between the suction side and the discharge side of the sub compressor. That is, when the expander is started, a resistance force corresponding to the pressure difference is generated in the sub compressor. Accordingly, there is a problem that this resistance force hinders the start-up of the expander and the start-up performance of the expander is lowered.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a refrigeration air conditioner capable of stably starting an expander.

The refrigeration air conditioner according to the present invention is provided between a refrigeration cycle circuit in which a main compressor, an intermediate cooler, a radiator, an expander, and an evaporator are sequentially connected by piping, and the intermediate cooler and the radiator, In a refrigeration air conditioner comprising a sub compressor driven by power recovered by an expander,
The first expansion valve provided between the expander and the evaporator, one end is connected between the radiator and the expander, and the other end is between the main compressor and the intercooler. The first bypass pipe connected to the first bypass valve, the first on-off valve provided in the first bypass pipe, one end is connected between the intermediate cooler and the sub compressor, and the other end is the first A second bypass pipe connected between the expansion valve and the evaporator; a second expansion valve provided in the second bypass pipe; and a connecting portion at one end of the sub compressor and the first bypass pipe. A first check valve provided between the first bypass pipe and the refrigerant flow from the first bypass pipe to the sub compressor.

In the present invention, the refrigerant that is compressed by the main compressor is turned into the intermediate cooler by opening the first on-off valve and the second expansion valve and starting the main compressor with the first expansion valve closed. It passes through the circuit of the second expansion valve → the evaporator → the main compressor. At this time, the expander is equalized by the discharge pressure of the main compressor. Further, the sub-compressor is equalized with a pressure that is reduced by a pressure loss generated when passing through the intermediate cooler from the discharge pressure of the main compressor. Note that the discharge pressure of the main compressor is adjusted to a predetermined pressure by the opening of the second expansion valve.
By opening the first expansion valve in this state, a pressure difference is generated between the suction side and the discharge side of the expander, and the expander is activated by this pressure difference. At this time, the pressure difference between the suction side and the discharge side of the sub compressor can be suppressed by equalizing the pressure of the sub compressor. That is, when starting up an expander, the resistance force which generate | occur | produces in a sub compressor by this pressure difference can be suppressed. Therefore, the start of the expander is not hindered, and the expander can be started stably.

It is a refrigerant circuit block diagram of the refrigeration air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a cross-sectional schematic diagram which shows the expansion / compression unit which concerns on Embodiment 1 of this invention. It is a flowchart which shows the control action of the refrigerating air-conditioning apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows typically the pressure which acts on an orbiting scroll in the state which the 1st expansion valve closed. It is a figure which shows typically the pressure which acts on the rocking scroll after opening a 1st expansion valve. It is a refrigerant circuit block diagram of the refrigeration air conditioning apparatus which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
1 is a refrigerant circuit configuration diagram of a refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention.
The refrigerating and air-conditioning apparatus 100 is a refrigerating and air-conditioning apparatus including a sub-compressor 5 connected by an expander 6 and a drive shaft 7 and arranging the sub-compressor 5 on the higher stage side of the two-stage compression.
The refrigerating and air-conditioning apparatus 100 includes a main compressor 1, an intermediate cooler 2, a sub compressor 5, a radiator 3, an expander 6, and an evaporator 4 that are sequentially connected by piping.

  The main compressor 1 is a compressor driven by a motor 8. The intermediate cooler 2 cools the high-temperature and high-pressure refrigerant compressed by the main compressor 1 and functions as a radiator. The sub compressor 5 is a compressor that is driven by the power collected by the expander 6. In the first embodiment, the sub compressor 5 and the expander 6 are connected by the drive shaft 7. That is, the power recovered by the expander 6 is transmitted to the sub compressor 5 by the drive shaft 7. In the first embodiment, the sub compressor 5 and the expander 6 are integrally formed as the expansion / compression unit 50. Details of the expansion / compression unit 50 will be described later.

  The radiator 3 cools the high-temperature and high-pressure refrigerant further compressed by the sub compressor 5. The expander 6 decompresses and expands the high-pressure refrigerant that has flowed out of the radiator 3. As described above, the expander 6 transmits the power recovered in the refrigerant expansion process to the sub compressor 5 via the drive shaft 7. The evaporator 4 heats the refrigerant decompressed and expanded by the expander 6 and the like.

  The refrigerating and air-conditioning apparatus 100 according to Embodiment 1 includes a first bypass pipe 9, a first on-off valve 10, a second bypass pipe 11, a second expansion valve 12, a first check valve 13, and a first expansion valve. A valve 14 is provided.

  The first expansion valve 14 is provided between the expander 6 and the evaporator 4. One end of the first bypass pipe 9 is connected between the radiator 3 and the expander 6 (the refrigerant suction side of the expander 6), and the other end is connected to the main compressor 1 and the intercooler 2. (Connected to the refrigerant discharge side of the main compressor 1). The first on-off valve 10 is provided in the first bypass pipe 9. One end of the second bypass pipe 11 is connected between the intermediate cooler 2 and the sub compressor 5 (the refrigerant outlet side of the intermediate cooler 2), and the other end is evaporated with the first expansion valve 14. It is connected to the evaporator 4 (the refrigerant inlet side of the evaporator 4). The second expansion valve 12 is provided in the second bypass pipe 11. The first check valve 13 is provided between the sub-compressor 5 and the connecting portion at one end of the first bypass pipe 9 (the refrigerant discharge side of the sub-compressor 5). The first check valve 13 regulates the refrigerant flow from the first bypass pipe 9 to the sub compressor 5.

  Further, the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 includes the rotational speed control of the main compressor 1 (motor 8), the opening and closing of the first on-off valve 10, the opening control of the second expansion valve 12, and the first A control device 60 that controls the opening degree of the expansion valve 14 and the like is provided.

  Such a refrigerating and air-conditioning apparatus 100 uses carbon dioxide, which is a natural refrigerant, as a refrigerant. The refrigerant used in the refrigerating and air-conditioning apparatus 100 is not limited to the carbon dioxide refrigerant, and various conventional refrigerants can also be used. In addition, since the refrigerant | coolant which operate | moves below a critical pressure in a thermal radiation process condenses in a thermal radiation process, the heat exchanger used for a thermal radiation process may be called a condenser. In the first embodiment and the following embodiments, regardless of the type of refrigerant, the heat exchanger used in the heat dissipation process is referred to as a “heat radiator”.

Next, details of the expansion / compression unit 50 will be described.
FIG. 2 is a schematic cross-sectional view showing the expansion / compression unit according to Embodiment 1 of the present invention.
In the expansion / compression unit 50, the expander 6 and the sub-compressor 5 are integrally formed as a double-sided scroll type with a back surface.
As shown in FIG. 2, the expansion / compression unit 50 includes a drive shaft 7, an orbiting scroll 16, a fixed scroll 17 that constitutes the sub compressor 5, a fixed scroll 18 that constitutes the expander 6, and the like. . The swing scroll 16, the fixed scroll 17, the fixed scroll 18, and the like are accommodated in a sealed container 30.

The swing scroll 16 has spiral teeth formed on both sides of the base plate. A fixed scroll 17 is provided above the swing scroll 16. Spiral teeth are formed on the lower surface portion of the fixed scroll 17, and the fixed scroll 17 is arranged so that the spiral teeth of the fixed scroll 17 and the spiral teeth on the upper surface side of the swing scroll 16 are combined. By combining the spiral teeth of the fixed scroll 17 and the spiral teeth on the upper surface side of the swing scroll 16, the compression chamber 17 a is interposed between the spiral teeth of the fixed scroll 17 and the spiral teeth on the upper surface side of the swing scroll 16. Is formed. A fixed scroll 18 is provided below the swing scroll 16. Spiral teeth are formed on the upper surface portion of the fixed scroll 18, and the fixed scroll 18 is arranged so that the spiral teeth of the fixed scroll 18 and the spiral teeth on the lower surface side of the swing scroll 16 are combined. By combining the spiral teeth of the fixed scroll 18 and the spiral teeth on the lower surface side of the swing scroll 16, the expansion chamber 18 a is interposed between the spiral teeth of the fixed scroll 18 and the spiral teeth on the lower surface side of the swing scroll 16. Is formed.
Further, an Oldham ring 24 that prevents the swing scroll 16 from rotating is provided between the swing scroll 16 and the fixed scroll 17.

The drive shaft 7 is provided through the rocking scroll 16, the fixed scroll 17, and the fixed scroll 18.
More specifically, the drive shaft 7 is supported by an upper bearing 27 of the fixed scroll 17 and a lower bearing 28 of the fixed scroll 18. Further, the slider 15 is provided on the rocking bearing 29 of the rocking scroll 16, and the drive shaft 7 is provided so as to penetrate the slider 15. That is, the drive shaft 7 is supported by the rocking bearing 29 of the rocking scroll 16 via the slider 15. The slider 15 is configured to be eccentric from the central axis of the drive shaft 7. Thus, the orbiting scroll 16 is pressed against the radial direction of the fixed scroll 17 and the fixed scroll 18, and the scroll side surface gap (formed between the spiral tooth side surface of the fixed scrolls 17 and 18 and the spiral tooth side surface of the orbiting scroll 16 is formed. The gap is reduced.
Further, an upper balance weight 19 and a lower balance weight 20 are installed in the vicinity of both ends of the drive shaft 7 so as to cancel the unbalance due to the centrifugal force of the swing scroll 16.

  An oil pump 22 is provided at the lower end of the drive shaft 7. As the drive shaft 7 rotates, the oil 31 stored in the lower portion of the sealed container 30 is sucked into an oil supply hole (not shown) formed in the drive shaft 7. Then, the oil 31 sucked into the oil supply hole is supplied to each bearing portion.

The expansion / compression unit 50 includes a suction pipe 17b for guiding the refrigerant flowing out from the intercooler 2 to the compression chamber 17a, a discharge pipe 17c for guiding the refrigerant flowing out from the compression chamber 17a to the radiator 3, and heat dissipation. A suction pipe 18b for guiding the refrigerant flowing out of the chamber 3 to the expansion chamber 18a and a discharge pipe 18c for guiding the refrigerant flowing out of the expansion chamber 18a to the evaporator 4 are provided.
More specifically, the discharge pipe 17c is provided so as to communicate with a space formed on the downstream side of the discharge port of the compression chamber 17a. A discharge valve 21 is provided at the discharge port of the compression chamber 17a. Further, the discharge pipe 18c is provided so as to communicate with a space formed on the downstream side of the discharge port of the expansion chamber 18a (a space formed on the outer peripheral side of the swing scroll 16).

  That is, in the expansion / compression unit 50, the sub compressor 5 is configured by the upper surface portion of the swing scroll 16 and the fixed scroll 17, and the expander 6 is configured by the lower surface portion of the swing scroll 16 and the fixed scroll 18. In other words, the drive shaft 7 is driven (power is recovered) in the process (expansion process) in which the refrigerant flowing into the expansion chamber 18a through the suction pipe 18b is discharged from the discharge pipe 18c. And when the drive shaft 7 drives, the refrigerant | coolant which flowed into the compression chamber 17a via the suction pipe 17b is compressed.

  The expansion / compression unit 50 is provided with a tip seal 23, an outer peripheral seal ring 25, and an inner peripheral seal ring 26. The tip seal 23 is provided at the tip of each swirl tooth formed on the orbiting scroll 16, the fixed scroll 17 and the fixed scroll 17. Thereby, the axial clearance between the orbiting scroll 16 and the fixed scroll 17 and the axial clearance between the orbiting scroll 16 and the fixed scroll 18 are reduced. The outer peripheral seal ring 25 is provided on the outer peripheral side of the orbiting scroll 16, and seals the suction side of the compression chamber 17a and the discharge side of the expansion chamber 18a. The inner circumferential seal ring 26 is provided on the inner circumferential side of the swing scroll 16 and seals the suction side of the expansion chamber 18 a and the space in the sealed container 30.

  The discharge valve 21 may be used as a substitute for the first check valve 13 provided on the discharge side of the sub compressor 5. In that case, a circuit configuration in which the first check valve 13 is not provided may be employed.

Next, the driving | operation operation | movement at the time of starting the expander 6 is demonstrated.
FIG. 3 is a flowchart showing the control operation of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention.
When an operation command is input from the user to the control device 60 (step S1), the control device 60 opens the first on-off valve 10 and the second expansion valve 12 and closes the first expansion valve 14 ( Step S2). Then, the control device 60 starts the main compressor 1 (step S3). The refrigerant compressed by the main compressor 1 is cooled by the intermediate cooler 2 and flows out from the intermediate cooler 2. At this time, since the sub compressor 5 and the expander 6 are stopped, the refrigerant flowing out from the intercooler 2 passes through the second bypass pipe 11 and the second expansion valve 12 and is heated by the evaporator 4. After that, it is sucked into the main compressor 1. At this time, the control device 60 controls the opening pressure of the second expansion valve 12 to control the discharge pressure and the suction pressure of the main compressor 1 to predetermined pressures (step S4).

  In a state before the sub compressor 5 and the expander 6 are activated, the suction side of the sub compressor 5 is lower than the discharge pressure of the main compressor 1 by the pressure loss generated when passing through the intermediate cooler 2. Pressure acts. Then, the refrigerant that has reached the suction side of the sub compressor 5 passes through the gap between the fixed scroll 17 and the swing scroll 16. As a result, the same pressure as the suction side acts on the discharge side of the sub-compressor 5, and the sub-compressor 5 has a constant pressure (pressure loss generated when passing through the intermediate cooler 2 from the discharge pressure of the main compressor 1. The pressure is equalized at a lower pressure). Since the sub compressor 5 is pressure-equalized, no pressure difference acts between the suction side and the discharge side of the sub compressor 5. For this reason, a resistance force such as a radial load generated by the pressure difference does not act on the drive shaft 7. That is, since the resistance force that inhibits the start of the expander 6 does not act, the startability of the expander 6 can be improved (the expander 6 can be started stably).

  In the state before the sub compressor 5 and the expander 6 are activated, the refrigerant discharged from the main compressor 1 passes through the first bypass pipe 9 and the first on-off valve 10 on the suction side of the expander 6. Acts directly through. For this reason, the pressure on the discharge side of the expander 6 becomes the discharge pressure of the main compressor 1. Since the first check valve 13 is provided on the discharge side of the sub compressor 5, the discharge pressure of the main compressor 1 does not act on the sub compressor 5. Further, since the first expansion valve 14 provided on the discharge side of the expander 6 is in a closed state, the refrigerant passes through the gap between the fixed scroll 18 and the swing scroll 16, and also on the discharge side of the expander 6. The same pressure as the suction side of the expander 6 acts. For this reason, the expander 6 is equalized by the discharge pressure of the main compressor 1 that is the suction side pressure of the expander 6.

  The pressure acting on the orbiting scroll 16 at this time is schematically shown in FIG. As shown in FIG. 4, the discharge pressure A of the main compressor 1 acts on the lower surface portion (the expander 6 side) of the orbiting scroll 16. On the other hand, a pressure B lower than the discharge pressure of the main compressor 1 by a pressure loss generated when passing through the intermediate cooler 2 acts on the upper surface portion (sub compressor 5 side) of the swing scroll 16. Since the pressure acting on the upper surface portion (sub compressor 5 side) of the orbiting scroll 16 is low by the pressure loss of the intercooler 2, the thrust load C (axial load) acting on the orbiting scroll 16 is upward. Works. That is, the swing scroll 16 is pressed against the fixed scroll 17. At this time, the control device 60 controls the opening degree of the second expansion valve 12 so that the pressure acting on the lower surface portion (the expander 6 side) of the orbiting scroll 16 becomes a predetermined pressure (step S4). Further, the control device 60 controls the rotational speed and the like of the main compressor 1 so that the pressure acting on the upper surface portion (sub compressor 5 side) of the orbiting scroll 16 becomes a predetermined pressure (step S4). That is, the control device 60 changes the refrigerant circulation amount by changing the number of revolutions of the main compressor 1 and adjusts the pressure loss generated in the intermediate cooler 2, so The pressure acting on the compressor 5 side) is controlled to be a predetermined pressure.

In step S5, the control device 60 determines whether or not the sub compressor 5 and the expander 6 are equalized. When the control device 60 determines that the sub compressor 5 and the expander 6 are equalized, the control device 60 opens the first expansion valve 14 (controls it to a predetermined opening degree). If the control device 60 determines that the sub compressor 5 and the expander 6 are not pressure-equalized, the control device 60 returns to step S4 and continues the opening control of the second expansion valve 12 and the rotation speed control of the main compressor 1. To do.
In the first embodiment, for example, when a pressure gauge is provided in the suction side pipe and the discharge side pipe of the sub compressor 5, and the difference between the detected values of these pressure gauges falls within a predetermined range, the control device 60 performs the sub compression. It is determined that the machine 5 is equalized. Further, for example, when a pressure gauge is provided in the suction side pipe and the discharge side pipe of the expander 6 and the difference between the detected values of these pressure gauges falls within a predetermined range, the control device 60 determines that the pressure in the expander 6 is equalized. ing.

  When the first expansion valve 14 is opened, the pressure on the discharge side of the expander 6 drops to the pressure on the inlet side of the evaporator 4. Finally, the pressure on the discharge side of the expander 6 and the pressure on the inlet side of the evaporator 4 are the same.

  FIG. 5 schematically shows the pressure acting on the orbiting scroll 16 after the first expansion valve 14 is opened. As shown in FIG. 5, the pressure acting on the upper surface portion (sub compressor 5 side) of the orbiting scroll 16 is lower than the discharge pressure of the main compressor 1 by the pressure loss generated when passing through the intermediate cooler 2. The pressure B is the same as before the first expansion valve 14 is opened. However, the pressure acting on the lower surface (the expander 6 side) of the orbiting scroll 16 decreases the pressure on the outer peripheral side of the orbiting scroll 16 by opening the first expansion valve 14. That is, the pressure on the outer peripheral side of the orbiting scroll 16 is a pressure D between the suction side pressure (discharge pressure of the main compressor 1) and the discharge side pressure (inlet side pressure of the evaporator 4). As the pressure on the outer peripheral side of the orbiting scroll 16 decreases, the load that pushes the orbiting scroll 16 upward decreases. For this reason, the thrust load C acting on the orbiting scroll 16 acts downward, which is the opposite direction to that before opening the first expansion valve 14. Therefore, the orbiting scroll 16 is pressed against the fixed scroll 18.

  Here, the thrust load C does not act on the orbiting scroll 16 at the moment when the direction of the thrust load C acting on the orbiting scroll 16 reverses from upward to downward. Further, the thrust load C acting on the orbiting scroll 16 becomes extremely small before and after the direction of the thrust load C is reversed. Since the thrust load C does not act on the rocking scroll 16 or becomes extremely small, the frictional force generated at the tips of the spiral teeth formed on the rocking scroll 16, the fixed scroll 17, and the fixed scroll 18 is reduced. This frictional force is a main factor of the resistance force that inhibits the start-up of the expander 6. Therefore, the expander 6 can be started more stably by reducing the frictional force generated at the tips of the spiral teeth formed on the fixed scroll 17 and the fixed scroll 18. Here, in the first embodiment, the control device 60 controls the thrust load C acting on the orbiting scroll 16 by controlling the opening degree of the first expansion valve 14 (step S6). In addition, when controlling the thrust load C which acts on the rocking scroll 16 by the time after opening the 1st expansion valve 14, you may comprise the 1st expansion valve 14 with an on-off valve like a solenoid valve.

When detecting the start of the expander 6 (step S7), the control device 60 closes the first on-off valve 10 and the second expansion valve 12 (step S8). And the control apparatus 60 transfers to a steady operation (step S9). Note that various methods can be used for detecting the start of the expander 6. For example, a rotation detection device that detects the rotation of the drive shaft 7 may be provided, and activation of the expander 6 may be detected based on a detection value of the rotation detection device.
The opening degree of the first expansion valve 14 after the steady operation is controlled by the control device 60 according to the cycle operation state.

  As described above, in the refrigerating and air-conditioning apparatus 100 configured as described above, the first bypass pipe 9, the first on-off valve 10, the second bypass pipe 11, the second expansion valve 12, the first check valve 13, and the first expansion valve. A valve 14 is provided. For this reason, since the sub compressor 5 is pressure-equalized before the expander 6 starts, a pressure difference does not act on the suction side and the discharge side of the sub compressor 5. That is, a resistance force such as a radial load generated by this pressure difference does not act on the drive shaft 7. Therefore, since the resistance force that hinders the start of the expander 6 does not act, the startability of the expander 6 can be improved (the expander 6 can be started stably).

  The expander 6 and the sub compressor 5 are integrally formed as a back-to-back double-side scroll type. For this reason, the frictional force generated at the tips of the spiral teeth formed on the fixed scroll 17 and the fixed scroll 18 can be reduced. Therefore, the expander 6 can be started more stably.

  Moreover, the refrigerating and air-conditioning apparatus 100 according to Embodiment 1 uses carbon dioxide as a refrigerant. When carbon dioxide is used as the refrigerant, since the operating pressure is high, the thrust load C acting on the orbiting scroll 16 becomes very large. For this reason, the refrigerating and air-conditioning apparatus 100 that starts the expander 6 by reducing the thrust load C significantly improves the startability of the expander 6 as compared with the conventional refrigerating and air-conditioning apparatus using carbon dioxide refrigerant. Can do.

In the first embodiment, the expander 6 and the sub compressor 5 are integrally formed as a back-to-back double-side scroll type, but the expander 6 and the sub compressor 5 may be formed separately. The expander 6 is not limited to the scroll type, and may be a rotary type, a multi-vane type, a screw type, or the like. The sub compressor 5 is not limited to the scroll type, and may be a rotary type, a multi-vane type, a screw type or the like. The power transmission from the expander 6 to the sub compressor 5 is not limited to the drive shaft 7 and may be transmitted by a belt or the like.
Even if it comprises in this way, since the resistance force which becomes a factor which inhibits starting of the expander 6 does not act, the startability of the expander 6 can be improved (the expander 6 can be started stably). it can).

  Further, in the first embodiment, the first check valve 13 is provided on the refrigerant inflow side of the radiator 3, but the refrigerant outflow side of the radiator 3 (more specifically, on the refrigerant outflow side of the radiator 3, You may provide the 1st non-return valve 13 in the refrigerant | coolant flow upstream rather than the connection part of the 1st bypass pipe 9 between the heat radiator 3 and the expander 6. FIG.

Embodiment 2. FIG.
By adding the following configuration, the time until the expander 6 is started can be shortened. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 6 is a refrigerant circuit configuration diagram of the refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention.
In the refrigeration air conditioner 101 according to the second embodiment, a third bypass pipe 40 and a second check valve 41 are added to the configuration of the refrigeration air conditioner 100 shown in the first embodiment. Other configurations are the same as those of the refrigerating and air-conditioning apparatus 100 shown in the first embodiment.

  One end of the third bypass pipe 40 is connected between the intermediate cooler 2 and the sub compressor 5 (the suction side of the sub compressor 5), and the other end is connected to the sub compressor 5 in the first reverse direction. It is connected between the stop valve 13 (the discharge side of the sub compressor 5). The connection position of the other end of the third bypass pipe 40 is not limited to the position shown in FIG. When the first check valve 13 is provided on the refrigerant outflow side of the radiator 3, the other end of the third bypass pipe 40 may be connected to the refrigerant outflow side of the radiator 3. That is, the connection position of the other end of the third bypass pipe 40 may be between the sub compressor 5 and the first check valve 13.

  The second check valve 41 is provided in the third bypass pipe 40. The second check valve 41 regulates the refrigerant flow from the discharge side to the suction side of the sub compressor 5.

The refrigerating and air-conditioning apparatus 101 configured as described above operates as follows in a state before the sub compressor 5 and the expander 6 are activated.
In a state before the sub compressor 5 and the expander 6 are activated, the suction side of the sub compressor 5 is lower than the discharge pressure of the main compressor 1 by the pressure loss generated when passing through the intermediate cooler 2. Pressure acts. Then, the refrigerant that has reached the suction side of the sub compressor 5 passes through the gap between the fixed scroll 17 and the swing scroll 16 and flows into the discharge side of the sub compressor 5. At this time, since the third bypass pipe 40 is provided in the second embodiment, the refrigerant that has reached the suction side of the sub compressor 5 flows into the discharge side of the sub compressor 5 through the third bypass pipe 40. You can also For this reason, the pressure equalization of the sub compressor 5 is accelerated, and the time from the start of the main compressor 1 to the start of the expander 6 can be shortened.
In addition, since the second check valve 41 is provided, it is possible to prevent the refrigerant discharged from the sub compressor 5 from flowing back to the suction side of the sub compressor 5 after shifting to the steady operation.

  DESCRIPTION OF SYMBOLS 1 Main compressor, 2 Intermediate cooler, 3 Heat radiator, 4 Evaporator, 5 Sub compressor, 6 Expander, 7 Drive shaft, 8 Motor, 9 1st bypass pipe, 10 1st on-off valve, 11 2nd bypass Pipe, 12 second expansion valve, 13 first check valve, 14 first expansion valve, 15 slider, 16 swing scroll, 17 fixed scroll, 17a compression chamber, 17b suction pipe, 17c discharge pipe, 18 fixed scroll, 18a Expansion chamber, 18b Suction pipe, 18c Discharge pipe, 19 Upper balance weight, 20 Lower balance weight, 21 Discharge valve, 22 Oil pump, 23 Tip seal, 24 Oldham ring, 25 Outer seal, 26 Inner seal, 27 Upper bearing, 28 Lower bearing, 29 Swing bearing, 30 Sealed container, 31 Oil, 40 Third bypass pipe, 41 Second check valve, 50 Expansion / compression Knit, 60 control unit, 100 refrigeration air conditioning system, 101 refrigeration air conditioning system.

Claims (5)

A refrigeration cycle circuit in which a main compressor, an intercooler, a radiator, an expander, and an evaporator are sequentially connected by piping;
A sub-compressor provided between the intermediate cooler and the radiator and driven by power recovered by the expander;
In the refrigeration air conditioner with
A first expansion valve provided between the expander and the evaporator;
A first bypass pipe having one end connected between the radiator and the expander, and the other end connected between the main compressor and the intercooler;
A first on-off valve provided in the first bypass pipe;
A second bypass pipe having one end connected between the intermediate cooler and the sub-compressor and the other end connected between the first expansion valve and the evaporator;
A second expansion valve provided in the second bypass pipe;
A first check valve provided between the sub-compressor and a connection portion of the one end of the first bypass pipe, and regulating a refrigerant flow from the first bypass pipe to the sub-compressor;
A refrigeration air conditioner characterized by comprising: A third bypass pipe having one end connected between the intermediate cooler and the sub-compressor and the other end connected between the sub-compressor and the first check valve;
A second check valve provided in the third bypass pipe for regulating a refrigerant flow from one end of the third bypass pipe to the other end of the third bypass pipe;
The refrigerating and air-conditioning apparatus according to claim 1, further comprising: The expander is a scroll type expander,
The sub compressor is a scroll type compressor,
The expander is formed on one surface side of the orbiting scroll,
The sub compressor is formed on the other surface side of the orbiting scroll,
The refrigerating and air-conditioning apparatus according to claim 1 or 2, wherein the expander and the sub-compressor are integrally formed as a back-to-back double-side scroll type. The first on-off valve and the second expansion valve are opened, the first expansion valve is closed, the main compressor is started to circulate the refrigerant,
By operating the opening of the second expansion valve to generate a predetermined pressure difference before and after the main compressor, the first expansion valve is opened to generate a pressure difference before and after the expander. The refrigerating and air-conditioning apparatus according to any one of claims 1 to 3, wherein the expander is activated.   The refrigerating and air-conditioning apparatus according to any one of claims 1 to 4, wherein carbon dioxide is used as the refrigerant.

Images