JP5036593B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus.

  As a refrigeration cycle apparatus, a structure having a compressor (sub-compressor) that preliminarily compresses refrigerant supplied to a main compressor (main compressor) is known. In general, such a refrigeration cycle apparatus includes a main compressor that compresses refrigerant, a radiator that cools the compressed refrigerant, an expander that expands the cooled refrigerant, an evaporator that evaporates the expanded refrigerant, and evaporation A refrigerant circuit is provided in which a sub-compressor that preliminarily compresses the refrigerant flowing out of the vessel and sends it to the main compressor is connected in order through a flow path. Further, in the refrigeration cycle apparatus provided with such a sub-compressor, the expansion shaft and the drive shaft of the sub-compressor are connected to one shaft, and the sub-compressor is driven by the power recovered from the refrigerant by the expander. A power recovery type refrigeration cycle apparatus is also known. Patent Documents 1 to 4 show a power recovery type refrigeration cycle apparatus or an air conditioner.

  The refrigeration cycle apparatus described in Patent Document 1 includes a refrigerant circuit in which a main compressor, a radiator, an expander, an evaporator, and a sub-compressor are connected in order through a flow path, and a power shaft is coupled to one shaft. The expander and the sub-compressor are disposed in a single sealed container that also serves as a lubricating oil receiver and a liquid refrigerant receiver.

  A refrigeration cycle apparatus described in Patent Document 2 includes a refrigerant circuit in which a main compressor, a radiator, an expander, an evaporator, a sub-compressor, and a suction accumulator having a function of storing refrigerant are connected in order through a flow path. The expander and the sub-compressor, each having a power shaft connected to a single shaft, are arranged in a single sealed container that also serves as a lubricating oil receiver and a liquid refrigerant receiver.

  Moreover, the air conditioning apparatus described in FIG. 4 of Patent Document 3 includes a main compressor, an indoor heat exchanger, an indoor decompression device, a liquid receiver that stores excess refrigerant, an expander, and heat exchange during heating operation. A refrigerant circuit in which a heat exchanger, an outdoor heat exchanger, and a sub-compressor are sequentially connected by a flow path, and a flow path from the outlet of the expander to the inlet of the heat exchanger is branched to expand the expansion valve and the heat It is connected to the flow path from the outlet of the subcompressor to the inlet of the compressor via an exchanger.

In the air conditioner described in FIG. 3 of Patent Document 4, during the heating operation, the main compressor, the indoor heat exchanger, the indoor expansion valve, the liquid receiver storing excess refrigerant, the heat exchanger, and the outdoor pressure reducing device A refrigerant circuit in which an outdoor heat exchanger and a sub-compressor are sequentially connected by a flow path, and the flow path from the outlet of the liquid receiver to the inlet of the heat exchanger is branched to expand the expander and the heat It is connected to the flow path from the outlet of the subcompressor to the inlet of the compressor via an exchanger.
JP 2004-325018 A JP 2004-325019 A JP 2006-125790 A JP 2006-125791 A

  When the power recovery type refrigeration cycle apparatus including the sub-compressor as described above is started, the main compressor is connected to a passage (hereinafter referred to as “suction”) connecting the outlet of the sub-compressor and the inlet of the main compressor. (Referred to as “side channel”) and sucked into a channel (hereinafter referred to as “discharge channel”) connected to the outlet of the main compressor. Since the sub-compressor is not operating at the time of starting, the pressure in the suction side flow path of the main compressor decreases until the expander is started. The amount of refrigerant in the suction side flow path of the main compressor at the time of startup is such that the refrigerant flows from the inlet to the outlet of the expander due to the high and low pressure difference and the expander starts up independently. Must be sufficient to boost. When the amount is less than this amount, the refrigerant to be sucked by the main compressor is insufficient, so that the refrigerant in the discharge-side flow path of the main compressor cannot be sufficiently boosted, and the expander does not start. . In particular, when the expander is a rotary type, the rotational torque required for startup varies depending on the phase of the power shaft of the expander. Therefore, depending on the rotation angle of the power shaft, the suction side of the main compressor at the time of startup The amount of refrigerant required for the flow path may increase.

  Compared with the refrigeration cycle apparatus described in Patent Document 1, the refrigeration cycle apparatus described in Patent Document 2 is provided with a suction accumulator that stores refrigerant in the suction-side flow path of the main compressor. A margin can be provided for the amount of refrigerant sucked in the main compressor. However, when the refrigeration cycle apparatus is provided with the suction accumulator, the apparatus may be increased in size or the amount of refrigerant in the refrigerant circuit may be excessive.

  Further, in comparison with the refrigeration cycle apparatus described in Patent Document 1, in the air conditioner described in Patent Documents 3 and 4, the main compressor at the time of start-up is an expander in addition to the suction side flow path of the main compressor. Since the refrigerant in the flow path from the outlet to the main compressor can be sucked through the heat exchanger, the intake refrigerant amount of the main compressor can be given a margin. However, since an outdoor heat exchanger or an indoor heat exchanger and a liquid receiver are provided in the flow path between the outlet of the main compressor and the inlet of the expander, pressure loss occurs, and the main compressor It is estimated that it takes time until the expander starts autonomously after starting.

  The present invention has been made to solve the above-described problems, and includes a main compressor, a supercharger (or sub-compressor) that preliminarily boosts a refrigerant supplied to the main compressor, In a refrigeration cycle apparatus having a feeder and an expander having a power shaft connected thereto, the shortage of refrigerant supply to the main compressor is solved at the start of the refrigeration cycle apparatus, and the expansion machine is promptly started, An object of the present invention is to provide a device that realizes reliable and stable start-up.

  The refrigeration cycle apparatus of the present invention includes a compressor that compresses refrigerant, a radiator that dissipates heat from the refrigerant compressed by the compressor, an expander that expands the refrigerant dissipated by the radiator and recovers power from the refrigerant, A first refrigerant circuit comprising: an evaporator for evaporating the refrigerant expanded by the expander; and a first refrigerant circuit in which a supercharger that boosts the refrigerant evaporated by the evaporator and sends the refrigerant to the compressor is sequentially connected through a connection flow path; A power recovery mechanism having a power recovery shaft for connecting the expander and the supercharger so that the supercharger is driven by the power recovered by the expander, the supercharger, and the expander; The first bypass path connected to the first refrigerant circuit so that the refrigerant flows from the outlet of the evaporator to the inlet of the compressor without passing through the supercharger, and both the radiator and the evaporator pass. Without the power recovery machine from the outlet of the compressor A second bypass path connected to the first refrigerant circuit so that the refrigerant flows to the inlet of the first refrigerant circuit, a state in which the refrigerant circulates through the first refrigerant circuit, a first bypass path and a second bypass path including the second bypass path A flow path switching mechanism that switches the flow of the refrigerant to a state in which the refrigerant circulates through the two refrigerant circuits is provided.

  Here, the upstream end of the second bypass path is connected to a connecting flow path between the outlet of the compressor and the inlet of the radiator, and the downstream end of the second bypass path is connected to the outlet of the evaporator and the supercharger. It is good to be connected to the connection flow path with the machine inlet. Alternatively, the upstream end of the second bypass passage is connected to a connection flow path between the outlet of the compressor and the inlet of the radiator, and the downstream end is connected to the outlet of the radiator and the inlet of the expander. It may be connected to the road.

  According to the above configuration, the main compressor at the time of starting can suck the refrigerant in the flow path from the outlet of the expander to the outlet of the evaporator through the first bypass passage. Insufficient supply of the refrigerant can be prevented. Furthermore, since the high-temperature and high-pressure refrigerant discharged from the main compressor flows directly to the power recovery mechanism through the second bypass passage without going through the heat radiator or evaporator, the power recovery mechanism (expander or It is possible to prompt quick start-up of the (supercharger).

  Further, in the refrigeration cycle apparatus, the refrigerant flows from the outlet of the supercharger without passing through the compressor to the portion from the outlet of the compressor to the inlet of the evaporator of the first refrigerant circuit. A third bypass path connected to the first refrigerant circuit and included in the second refrigerant circuit may be further provided.

  According to the present invention, when the refrigerant is circulated through the second refrigerant circuit when the refrigeration cycle apparatus is activated, the shortage of refrigerant supply to the main compressor that is activated first is resolved, and the power recovery mechanism can be activated quickly. Inspired, a reliable and stable start-up of the device can be realized.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIG. 1, FIG. 3, and FIG. 1 is a circuit diagram of a refrigeration cycle apparatus according to Embodiment 1, FIG. 3 is a circuit diagram during steady operation of the refrigeration cycle apparatus according to Embodiment 1, and FIG. 4 is a start-up of the refrigeration cycle apparatus according to Embodiment 1. It is a circuit diagram at the time. In FIG. 1, the refrigerant flow during steady operation is indicated by a chain line arrow, and the refrigerant flow at startup is indicated by a solid line arrow. 3 and 4, the flow path through which the refrigerant circulates is indicated by a solid line, and the flow path through which the refrigerant does not circulate is indicated by a chain line.

[Configuration of refrigeration cycle equipment]
First, the configuration of the refrigeration cycle apparatus 10 will be described. As shown in FIG. 1, the refrigeration cycle apparatus 10 includes a refrigerant circuit 16 in which a refrigerant that is a working fluid circulates. The refrigerant circuit 16 includes a main compressor 11 that compresses the refrigerant, a radiator 12 that dissipates the refrigerant that has been boosted by the main compressor 11 to a high temperature and a high pressure, and an expansion that expands the refrigerant radiated by the radiator 12. An evaporator 14 for evaporating the refrigerant expanded in the expander 13, a supercharger 15 for preliminarily compressing the refrigerant evaporated in the evaporator 14 and supplying it to the main compressor 11, and these are sequentially connected And a connecting flow path. The refrigerant flowing through the refrigerant circuit 16 is a carbon dioxide refrigerant. However, the refrigerant is not limited to the carbon dioxide refrigerant, and a refrigerant generally used for a refrigeration cycle can be used.

  The refrigeration cycle apparatus 10 is a power recovery type, and is provided with a power recovery shaft 17 in which the power shaft of the expander 13 and the power shaft of the supercharger 15 are connected to one shaft. The expander 13, the power recovery shaft 17 and the supercharger 15 constitute a power recovery mechanism 18. In the power recovery mechanism 18, the expansion energy of the refrigerant expanding in the expander 13 is recovered and converted into mechanical energy (rotational energy) for rotating the power recovery shaft 17, and supercharging is performed by rotating the power recovery shaft 17. The machine 15 is driven.

  In this Embodiment, the connection flow path which connects the main compressor 11, the heat radiator 12, the expander 13, the evaporator 14, and the supercharger 15 in order is formed with piping. These connection channels include a discharge-side channel 61 that connects the outlet of the main compressor 11 and the inlet of the radiator 12, and a connection channel 62 that connects the outlet of the radiator 12 and the inlet of the expander 13. A connection channel 63 that connects the outlet of the expander 13 and the inlet of the evaporator 14, a connection channel 64 that connects the outlet of the evaporator 14 and the inlet of the supercharger 15, A suction-side flow path 65 that connects the outlet and the inlet of the main compressor 11 is included.

  The main compressor 11 is a fluid machine that compresses and sends the refrigerant flowing through the refrigerant circuit 16 to a high temperature and high pressure. As the compressor 11, for example, a scroll compressor or a rotary compressor can be used. In the present embodiment, the compressor 11 includes a compression mechanism unit 11a and a drive unit 11b that drives the compression mechanism unit 11a. The compression mechanism portion 11a and the drive portion 11b are disposed in one sealed container 11c that stores lubricating oil.

  The radiator 12 is a heat exchanger that is provided downstream of the main compressor 11 in the refrigerant circuit 16 and radiates the refrigerant compressed by the main compressor 11. The radiator 12 plays a role of heating the surrounding medium in the refrigeration cycle apparatus 10.

  The expander 13 is a fluid machine that is provided downstream of the radiator 12 in the refrigerant circuit 16 and expands the low-temperature and high-pressure refrigerant that has flowed out from the outlet of the radiator 12. As the expander 13, for example, a scroll expander, a rotary expander, or a fluid pressure motor can be used. The fluid pressure motor is a fluid machine that does not include an expansion step, and that substantially continuously performs a step of sucking the refrigerant from the radiator 12 and a step of discharging the sucked refrigerant.

  The evaporator 14 is a heat exchanger that is provided downstream of the expander 13 in the refrigerant circuit 16 and heats and evaporates the refrigerant flowing out of the expander 13. The evaporator 14 plays a role of cooling the surrounding medium in the refrigeration cycle apparatus 10.

  The supercharger 15 is disposed between the evaporator 14 and the main compressor 11, sucks the refrigerant from the evaporator 14, preliminarily increases the pressure, and discharges it to the suction-side flow path 65 of the main compressor 11. It is a fluid machine. As the supercharger 15, a scroll compressor, a rotary compressor, or a fluid pressure motor compressor can be used. The fluid pressure motor type compressor is a compressor that substantially continuously performs the step of sucking the refrigerant from the evaporator 14 and the step of discharging the sucked refrigerant to the main compressor 11 side.

  As described above, the power recovery mechanism 18 is configured by the expander 13, the supercharger 15, and the power recovery shaft 17 connecting these power shafts. The expander 13 recovers the expansion energy of the refrigerant and converts it into mechanical energy, the power recovery shaft 17 transmits the recovered mechanical energy to the supercharger 15, and the supercharger 15 transmits the transmitted mechanical energy. To compress the refrigerant. The expander 13, the supercharger 15, and the power recovery shaft 17 are disposed in a sealed container 19 in which lubricating oil is stored. In the present embodiment, the power recovery mechanism 18 and the main compressor 11 are housed in independent sealed containers. However, in order to reduce the installation space, these are housed together in one sealed container. Can also be used.

  The power recovery mechanism 18 is provided with activation detection means 33 for detecting that the power recovery mechanism 18 is activated. When the power recovery mechanism 18 is activated, a difference occurs in the refrigerant temperature and pressure between the inlet and the outlet of the expander 13, and the power recovery shaft 17 starts to rotate. Therefore, as the activation detection means 33, a temperature measurement means for detecting the temperature difference of the refrigerant between the inlet and the outlet of the expander 13 can be provided. Further, instead of the temperature measuring means, a pressure detecting means for detecting the pressure difference of the refrigerant between the inlet and the outlet of the expander 13 or a shaft rotational speed detecting means for detecting the rotational speed of the power recovery shaft 17 is provided. You can also. Further, since the power recovery mechanism 18 is started at a substantially constant time after the main compressor 11 is started, the power recovery mechanism 18 is provided with a timer for measuring the time since the main compressor 11 is started as the start detection means 33. You can also.

  In the refrigeration cycle apparatus 10 having the above-described configuration, the refrigerant circulates through the refrigerant circuit 16 during standby and steady operation (FIG. 3). When the refrigeration cycle apparatus 10 is activated, the refrigerant circulates through a second refrigerant circuit (hereinafter referred to as “activation refrigerant circuit 16A”) that uses the refrigerant circuit 16 during steady operation but is different from the refrigerant circuit 16 (hereinafter referred to as “activation refrigerant circuit 16A”). FIG. 4). The starting refrigerant circuit 16 </ b> A is formed by the refrigerant circuit 16 and three bypass paths 81, 82 </ b> A, 83 </ b> A connected to the refrigerant circuit 16. A flow path switching mechanism for switching the flow of the refrigerant into a state where the refrigerant circulates through the refrigerant circuit 16 and a state where the refrigerant circulates through the activation refrigerant circuit 16A including the bypass passages 81, 82A, 83A is a refrigeration cycle. The device 10 is provided.

  The first bypass path 81 is a flow path connected to the refrigerant circuit 16 so that the refrigerant flows directly from the outlet of the evaporator 14 to the inlet of the main compressor 11 without passing through the supercharger 15. Specifically, the upstream end of the first bypass passage 81 is connected to the connection flow path 64 between the evaporator 14 and the supercharger 15, and the downstream end is connected to the suction side flow path 65 of the main compressor 11. Yes. Here, “directly” means that a fluid machine or a heat exchanger is not interposed therebetween, and a connection channel and a bypass channel may be interposed.

  Also, the second bypass path 82A is a refrigerant circuit so that the refrigerant flows directly from the outlet of the main compressor 11 to the inlet of the power recovery mechanism 18 without passing through either the radiator 12 or the expander 13 that is a heat exchanger. 16 is a flow path connected to 16. The inlet of the power recovery mechanism 18 includes an inlet of the expander 13 and an inlet of the supercharger 15, and the second bypass 82 </ b> A according to the present embodiment is a flow path that sends the refrigerant to the inlet of the supercharger 15. is there. Specifically, the upstream end of the second bypass passage 82A is connected to the discharge side flow passage 61 of the main compressor 11, and the downstream end is connected to the connection flow passage 64 between the evaporator 14 and the supercharger 15. Yes.

  Further, the third bypass passage 83 </ b> A allows the refrigerant to flow from the outlet of the supercharger 15 to the portion from the outlet of the main compressor 11 of the refrigerant circuit 16 to the inlet of the evaporator 14 without passing through the main compressor 11. A flow path connected to the circuit 16. The third bypass passage 83A according to the present embodiment has an upstream end connected to the suction-side flow path 65 of the main compressor 11 and a downstream end connected to the connection flow path 62 between the radiator 12 and the expander 13. Has been.

  In the connection flow path 64 between the outlet of the evaporator 14 and the inlet of the supercharger 15, a four-way valve 21 as a flow path switch is provided so as to divide the connection flow path 64 into an upstream side and a downstream side. Yes. The four-way valve 21 is connected to the upstream end of the first bypass passage 81 and the downstream end of the second bypass passage 82A. The four-way valve 21 receives a control signal from the control device 31, and the upstream side and the downstream side of the connection channel 64 communicate with each other (during operation standby and steady operation), and the upstream side of the connection channel 64. And the upstream end (at the time of activation) of the first bypass path 81 and the downstream side of the connection flow path 64 and the downstream end of the second bypass path 82A are switched to each other. With this configuration, the refrigerant flows from the evaporator 14 to the supercharger 15 during operation standby and steady operation, and the refrigerant flows directly from the evaporator 14 to the main compressor 11 during startup. The four-way valve 21 includes, for example, a valve body in which a slider for switching a fluid flow is built in a cylinder, a pilot valve that generates fluid pressure for moving the slider in the cylinder, a pilot valve driving solenoid, What was comprised by this can be used.

  Further, a four-way valve 23 as a flow path switch is provided in the suction side flow path 65 that connects the outlet of the supercharger 15 and the inlet of the main compressor 11, and the suction side flow path 65 is arranged upstream and downstream. It is provided to divide. The four-way valve 23 is connected to the downstream end of the first bypass passage 81 and the upstream end of the third bypass passage 83A. Then, the four-way valve 23 receives a control signal from the control device 31, the state where the upstream side and the downstream side of the suction side flow path 65 are communicated (during operation standby and during steady operation), and the suction side flow path 65. And the upstream end of the third bypass passage 83A are in communication with each other and the downstream side of the suction-side passage 65 and the downstream end of the first bypass passage 81 are in communication with each other (when activated). Has been. With this configuration, the refrigerant flows from the supercharger 15 to the main compressor 11 during operation standby and steady operation, and the refrigerant flows directly from the supercharger 15 to the expander 13 at startup.

  Further, a switching valve 22 is provided at a connection portion between the upstream end of the second bypass passage 82 </ b> A and the discharge side passage 61 of the main compressor 11. This switching valve 22 is, for example, a three-way valve. The switching valve 22 receives a control signal from the control device 31, and a state in which the refrigerant flows through the refrigerant circuit 16 side (during operation standby and normal operation) and a state in which the refrigerant flows through the second bypass passage 82A (at the time of activation). In addition, the refrigerant flow is switched. With this configuration, the refrigerant flows directly from the main compressor 11 to the radiator 12 during operation standby and steady operation, and at the start-up, the refrigerant flows from the main compressor 11 to the second bypass path 82A.

  As described above, the flow path switching mechanism is formed by the four-way valves 21 and 23 and the switching valve 22 provided at the connection portion between the refrigerant circuit 16 and the bypass paths 81, 82A, and 83A, and these valves are switched. As a result, the refrigerant circuit 16 can be established during standby and steady operation of the refrigeration cycle apparatus 10, and the activation refrigerant circuit 16A can be established when the refrigeration cycle apparatus 10 is activated.

  As shown in FIG. 3, in the refrigerant circuit 16, the refrigerant circulates in the order of the main compressor 11 → the radiator 12 → the expander 13 → the evaporator 14 → the supercharger 15 → the main compressor 11. When the refrigerant can circulate through the refrigerant circuit 16, no refrigerant flows through the first bypass path 81, the second bypass path 82A, and the third bypass path 83A.

  Further, as shown in FIG. 4, in the starting refrigerant circuit 16 </ b> A, the refrigerant circulates in the order of the main compressor 11 → the supercharger 15 → the expander 13 → the evaporator 14 → the main compressor 11. When the refrigerant can be circulated through the startup refrigerant circuit 16A, the refrigerant does not flow through the radiator 12.

  The operation of the refrigeration cycle apparatus 10 having the above configuration is controlled by the control device 31. The control device 31 is configured as a microprocessor centered on a CPU, and includes a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port, and a communication port in addition to the CPU. Yes.

  The control device 31 includes a start detection signal from the start detection unit 33 for detecting that the power recovery mechanism 18 has started, and a state of the switching valve 22 from a state detection unit (not shown) provided in the switching valve 22. Signals, state signals of the four-way valves 21 and 23 from the state detection means (not shown) provided in the four-way valves 21 and 23, and operation signals from the operation tool 32 including a start button, an operation button, etc. Input through port. The control device 31 executes a predetermined program stored in the ROM by the CPU, receives these input signals, and receives a drive signal to the drive unit 11b of the main compressor 11 and a control signal to the switching valve 22. The control signal to the four-way valves 21 and 23, the display signal to the operation tool 32, and the like are output via the input / output port.

[Operation of refrigeration cycle equipment]
Next, operation | movement of the refrigerating-cycle apparatus 10 is demonstrated using FIGS. FIG. 2 is a flowchart of start-up of the refrigeration cycle apparatus according to the first embodiment.

  In the refrigeration cycle apparatus 10 during operation standby, the main compressor 11 is stopped and the refrigerant can circulate through the refrigerant circuit 16, but the refrigerant does not flow (FIG. 3). Here, as shown in FIG. 2, when a start command is input from the operating tool 32 to the control device 31 (step S41), the control device 31 causes the start-up refrigerant circuit to flow the refrigerant through the bypass passages 81, 82A, 83A. A control signal is output to the four-way valves 21 and 23 and the switching valve 22 so as to switch the valves to form 16A (step S42). Thereby, the refrigerant can circulate through the startup refrigerant circuit 16A (FIG. 4).

  Subsequently, the control device 31 outputs an activation signal to the main compressor 11 (step S43). The started main compressor 11 sucks the refrigerant at the inlet of the main compressor 11 from the outlet of the expander 13 in the starting refrigerant circuit 16A, compresses it to high temperature and high pressure, and discharges it. That is, the main compressor 11 at the time of start-up includes the four-way valve 21 among the connection flow path 63 between the expander 13 and the evaporator 14, the inside of the evaporator 14, and the connection flow path 64 between the evaporator 14 and the supercharger 15. From the four-way valve 23 of the upstream portion, the first bypass passage 81, and the discharge side flow passage 61 of the main compressor 11, the refrigerant in the downstream portion can be sucked. Therefore, since the refrigerant having a larger volume can be sucked compared to the discharge-side flow path 61 of the main compressor 11, a shortage of refrigerant supply to the main compressor 11 at the time of start-up can be prevented, and reliable and stable. Can be realized.

  In the starting refrigerant circuit 16A, the outlet of the main compressor 11 and the inlet of the supercharger 15 are communicated with each other by the second bypass passage 82A. Therefore, when the high-temperature and high-pressure refrigerant is discharged from the main compressor 11, Both the pressure and temperature of the refrigerant at the inlet of the supercharger 15 rise. Therefore, the refrigerant on the inlet side of the supercharger 15 has a higher pressure than the refrigerant on the outlet side, and a differential pressure is generated in the refrigerant between the inlet side and the outlet side of the supercharger 15. Here, the supercharger 15 serves as a fluid pressure motor to absorb the flow energy of the refrigerant flowing through the supercharger 15, or the supercharger 15 serves as an expander to expand the refrigerant flowing through the supercharger 15. The energy is absorbed and converted into mechanical energy for rotating the power recovery shaft 17. That is, the supercharger 15 at the time of activation functions as a power recovery unit of the power recovery mechanism 18.

  At this time, since the supercharger 15 has not been activated, the refrigerant passing through the supercharger 15 is slightly decompressed and flows out of the supercharger 15 at a high temperature and intermediate pressure. In the starting refrigerant circuit 16A, the outlet of the supercharger 15 and the inlet of the expander 13 communicate with each other by the third bypass passage 83A. Both the pressure and temperature of the refrigerant at the inlet of the machine 13 rise. On the other hand, since the main compressor 11 sucks the refrigerant in the connection flow path 63 communicating with the outlet side of the expander 13, the pressure of the refrigerant on the outlet side of the expander 13 decreases. In this way, the refrigerant pressure difference between the inlet side and the outlet side of the expander 13 increases.

  Eventually, when the refrigerant flow from the inlet to the outlet of the expander 13 is caused by the refrigerant pressure difference between the inlet and outlet of the expander 13, the expander 13 is activated. The activated expander 13 functions as a power recovery unit of the power recovery mechanism 18, absorbs the expansion energy of the refrigerant flowing through the expander 13, and converts it into mechanical energy for rotating the power recovery shaft 17. With this energy, the power recovery shaft 17 rotates and the power recovery mechanism 18 starts up independently. At this time, since the energy is applied to the power recovery shaft 17 in the supercharger 15 as described above, the power recovery mechanism 18 can be started more quickly.

  The refrigerant that has expanded through the expander 13 and has become high temperature and low pressure flows through the evaporator 14 and then is sucked into the main compressor 11 again. Since the refrigerant circulating through the startup refrigerant circuit 16A does not pass through the radiator 12, the refrigerant flowing through the evaporator 14 is at a higher temperature than during steady operation. Thus, defrosting of the evaporator 14 is performed by the high-temperature refrigerant flowing through the evaporator 14 at the time of startup.

  When the control device 31 detects that the power recovery mechanism 18 has started autonomously through the activation detection means 33 (YES in step S44), the four-way valves 21 and 23 and the switching valve are switched so as to switch the valves to form the refrigerant circuit 16. A control signal is output to 22 (step S45). As a result, the refrigerant can be circulated in the refrigerant circuit 16, and the refrigerant begins to circulate through the refrigerant circuit 16, and the operation is shifted to the steady operation.

Note that the method for detecting that the power recovery mechanism 18 has started independently varies depending on the type of the activation detection means 33. Specifically, it is as shown in the following (1) to (4).
(1) In the case where the activation detection unit 33 is a temperature measurement unit that detects the refrigerant temperature difference between the inlet and the outlet of the expander 13, the inlet of the expander 13 when the experimentally obtained expander 13 starts autonomously The temperature difference ΔT between the refrigerant and the outlet is set in the control device 31. The control device 31 determines that the power recovery mechanism 18 has started autonomously when the temperature difference measured by the temperature measurement means becomes ΔT.
(2) When the activation detection means 33 is a pressure detection means for detecting the refrigerant pressure difference between the inlet and the outlet of the expander 13, the inlet of the expander 13 when the experimentally obtained expander 13 starts autonomously The pressure difference ΔP between the refrigerant and the outlet is set in the control device 31. The control device 31 determines that the power recovery mechanism 18 has started autonomously when the pressure difference detected by the pressure detection means becomes ΔP.
(3) When the activation detection means 33 is a timer, a time t from the start of activation of the main compressor 11 to the activation of the power recovery mechanism 18 determined experimentally is set in the control device 31. The control device 31 transmits a control signal to the drive unit 11b of the main compressor 11 and starts time measurement, and determines that the power recovery mechanism 18 has started autonomously when t has elapsed after the start of time measurement.
(4) When the activation detection means 33 is the rotation speed detection means of the power recovery shaft 17, the rotation speed N of the power recovery shaft 17 when the expander 13 obtained by experiment is stably operated is given to the control device 31. Is set. The control device 31 determines that the power recovery mechanism 18 has started autonomously when the rotational speed detected by the rotational speed detection means becomes N.

  In the refrigeration cycle apparatus 10 during steady operation, the refrigerant flows through the refrigerant circuit 16. Here, the high-temperature and high-pressure refrigerant discharged from the main compressor 11 dissipates heat while flowing through the radiator 12, becomes low-temperature and high-pressure, then flows through the expander 13 and expands into low-temperature and low-pressure, and further the evaporator 14 Evaporates to flow into low-pressure saturated steam. Thus, the refrigerant evaporated in the evaporator 14 is sucked into the supercharger 15 and preliminarily compressed, then discharged, and sucked into the main compressor 11.

  As described above, since the refrigeration cycle apparatus 10 according to the present embodiment includes the first bypass passage 81, the main compressor 11 at the time of startup is a flow from the outlet of the expander 13 to the outlet of the evaporator 14. The refrigerant in the passage can be sucked. Since the volume of the flow path from the outlet of the expander 13 to the outlet of the evaporator 14 includes the flow path in the evaporator 14, it is much smaller than the suction side flow path 65 of the main compressor 11 during steady operation. It is a big volume. Therefore, it is possible to solve the shortage of refrigerant supply to the main compressor 11 at the time of starting, and to realize a reliable and stable starting.

  Further, since the refrigeration cycle apparatus 10 according to the present embodiment includes the second bypass passage 82A, the refrigerant pressure at the inlet of the supercharger 15 is increased by the refrigerant discharged from the main compressor 11 at the time of startup. Thus, a differential pressure is generated in the refrigerant between the inlet and the outlet of the supercharger 15. As a result, the supercharger 15 functions as a power recovery unit of the power recovery mechanism 18 and the self-sustained activation of the power recovery mechanism 18 is promoted.

  Note that in a general positive displacement fluid machine, the density of the refrigerant is smaller on the compression stroke side than on the expansion process side, so that the supercharger 15 has a larger refrigerant volume than the expander 13. . For this reason, in order to give fluid energy to the stationary power recovery mechanism 18 so as to self-activate it, if the rotational moment is transmitted to the other party via the power recovery shaft 17, an expansion with a small volume is taken into consideration. It is more efficient to give fluid energy to the supercharger 15 having a larger volume than the machine 13.

  Further, since the refrigeration cycle apparatus 10 according to the present embodiment includes the third bypass passage 83A, the refrigerant pressure at the inlet of the expander 13 is increased by the refrigerant discharged from the supercharger 15 at the time of startup. A differential pressure is generated in the refrigerant between the inlet and the outlet of the expander 13. As a result, in addition to the above-described supercharger 15, the expander 13 also functions as a power recovery unit of the power recovery mechanism 18, and fluid energy can be recovered using both the supercharger 15 and the expander 13. The power recovery mechanism 18 can be activated independently.

  In addition, in the refrigeration cycle apparatus 10 according to the present embodiment, the startup refrigerant circuit 16A does not include the radiator 12, so the refrigerant flowing through the evaporator 14 at the time of startup is hotter than during steady operation. For this reason, defrosting of the evaporator 14 can be performed with the start-up of the refrigeration cycle apparatus 10. However, it is not limited to the time of starting, and the evaporator 14 can be defrosted by circulating the refrigerant in the starting refrigerant circuit 16A.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a circuit diagram of the refrigeration cycle apparatus according to the second embodiment, and FIG. 6 is a circuit diagram when the refrigeration cycle apparatus according to the second embodiment is started. In FIG. 5, the refrigerant flow during steady operation is indicated by a chain line arrow, and the refrigerant flow at startup is indicated by a solid line arrow. In FIG. 6, the starting refrigerant circuit is shown by a solid line.

  As shown in FIG. 5, the refrigeration cycle apparatus 10 according to the second embodiment is provided with a third bypass path 83B instead of the third bypass path 83A, unlike the refrigeration cycle apparatus 10 according to the first embodiment. Therefore, the third bypass path 83B will be described in detail below, and description of other parts will be omitted.

  The third bypass passage 83 </ b> B is a passage connected to the refrigerant circuit 16 so that the refrigerant flows directly from the outlet of the supercharger 15 to the inlet of the radiator 12 without passing through the main compressor 11. Specifically, the upstream end of the third bypass passage 83 </ b> B is connected to the suction side flow path 65 of the main compressor 11, and the downstream end is connected to the discharge side flow path 61 of the main compressor 11.

  The downstream end of the first bypass path 81 and the upstream end of the third bypass path 83B are connected to one four-way valve 23. The four-way valve 23 is provided so as to divide the suction side flow path 65 of the main compressor 11 into an upstream side and a downstream side. With this four-way valve 23, the upstream side and downstream side of the suction side flow path 65 communicate with each other (during operation standby and steady operation), and the upstream side of the suction side flow path 65 and the third bypass path 83B. The flow of the refrigerant can be switched to a state (at the time of activation) where the first bypass passage 81 and the downstream side of the suction side passage 65 are communicated with each other. Accordingly, during standby and steady operation, the refrigerant flows from the supercharger 15 to the main compressor 11, and at startup, the refrigerant flows directly from the supercharger 15 to the radiator 12, and from the evaporator 14 to the main compressor. The refrigerant will flow directly to 11.

  In the refrigeration cycle apparatus 10, the four-way valves 21, 23 and the switching valve 22 provided at the connection portion between the refrigerant circuit 16 and each bypass path 81, 82 </ b> A, 83 </ b> B are switched, so The refrigerant circuit 16 can be established during operation, and the activation refrigerant circuit 16A can be established when the refrigeration cycle apparatus 10 is activated.

  As shown in FIG. 5, in the refrigerant circuit 16, the refrigerant circulates in the order of the main compressor 11 → the radiator 12 → the expander 13 → the evaporator 14 → the supercharger 15 → the main compressor 11. When the refrigerant can circulate through the refrigerant circuit 16, no refrigerant flows through the first bypass path 81, the second bypass path 82A, and the third bypass path 83B.

  As shown in FIG. 6, in the starting refrigerant circuit 16 </ b> A, the refrigerant circulates in the order of the main compressor 11 → the supercharger 15 → the radiator 12 → the expander 13 → the evaporator 14 → the main compressor 11.

[Operation of refrigeration cycle equipment]
Next, the operation of the refrigeration cycle apparatus 10 having the above configuration will be described. Note that the operation during standby and steady operation of the refrigeration cycle apparatus 10 according to the second embodiment is the same as that during the refrigeration cycle apparatus according to the first embodiment, and therefore only the operation during startup will be described here. .

  In the refrigeration cycle apparatus 10 at the time of activation, the four-way valves 21 and 23 and the switching valve 22 are switched so that the refrigerant flows through the bypass passages 81, 82A, and 83B, and the activation refrigerant circuit 16A is established. When the main compressor 11 is started, the main compressor 11 sucks the refrigerant at the inlet of the main compressor 11 from the outlet of the expander 13 in the starting refrigerant circuit 16A, compresses it to high temperature and high pressure, and discharges it. That is, the main compressor 11 at the time of start-up includes the four-way valve 21 among the connection flow path 63 between the expander 13 and the evaporator 14, the inside of the evaporator 14, and the connection flow path 64 between the evaporator 14 and the supercharger 15. From the four-way valve 23 of the upstream portion, the first bypass passage 81, and the discharge side flow passage 61 of the main compressor 11, the refrigerant in the downstream portion can be sucked. Therefore, since the refrigerant having a larger volume can be sucked compared to the discharge-side flow path 61 of the main compressor 11, a shortage of refrigerant supply to the main compressor 11 at the time of start-up can be prevented, and reliable and stable. Can be realized.

  In the starting refrigerant circuit 16A, the outlet of the main compressor 11 and the inlet of the supercharger 15 are communicated with each other by the second bypass passage 82A. Therefore, when the high-temperature and high-pressure refrigerant is discharged from the main compressor 11, Both the pressure and temperature of the refrigerant at the inlet of the supercharger 15 rise. Therefore, the refrigerant on the inlet side of the supercharger 15 has a higher pressure than the refrigerant on the outlet side, and a differential pressure is generated in the refrigerant between the inlet side and the outlet side of the supercharger 15. Here, the supercharger 15 absorbs the flow energy of the refrigerant or the expansion energy of the refrigerant and converts it into mechanical energy for rotating the power recovery shaft 17. That is, the supercharger 15 at the time of activation functions as a power recovery unit of the power recovery mechanism 18.

  While passing through the supercharger 15, the refrigerant is slightly depressurized to an intermediate temperature and intermediate pressure. In the start-up refrigerant circuit 16A, the outlet of the supercharger 15 and the inlet of the radiator 12 are communicated with each other by the third bypass passage 83B. The pressure of the refrigerant at the inlet increases. On the other hand, since the main compressor 11 sucks the refrigerant in the connection flow path 63 communicating with the outlet side of the expander 13, the pressure of the refrigerant on the outlet side of the expander 13 decreases. In this way, the refrigerant pressure difference between the inlet side and the outlet side of the expander 13 increases.

  Eventually, when the refrigerant flow from the inlet to the outlet of the expander 13 is caused by the refrigerant pressure difference between the inlet and outlet of the expander 13, the expander 13 is activated. The activated expander 13 functions as a power recovery unit of the power recovery mechanism 18, absorbs the expansion energy of the refrigerant flowing through the expander 13, and converts it into mechanical energy for rotating the power recovery shaft 17. With this energy, the power recovery shaft 17 rotates and the power recovery mechanism 18 starts up independently. At this time, since the energy is applied to the power recovery shaft 17 in the supercharger 15 as described above, the power recovery mechanism 18 can be started more quickly.

  Thus, when the power recovery mechanism 18 starts up autonomously, the four-way valves 21, 23 and the switching valve 22 are switched so that the refrigerant does not flow into the bypass passages 81, 82A, 83B, and the refrigerant begins to circulate through the refrigerant circuit 16 and becomes steady. Transition to driving.

  As described above, since the refrigeration cycle apparatus 10 according to the present embodiment includes the first bypass passage 81, the main compressor 11 at the time of startup is a flow from the outlet of the expander 13 to the outlet of the evaporator 14. The refrigerant in the passage can be sucked. Therefore, it is possible to solve the shortage of refrigerant supply to the main compressor 11 at the time of starting, and to realize a reliable and stable starting.

  Furthermore, since the refrigeration cycle apparatus 10 according to the present embodiment includes the second bypass passage 82A, power recovery is performed by both the supercharger 15 and the expander 13 at the time of start-up, so that power can be supplied more quickly. The collection mechanism 18 can be activated independently.

  Moreover, since the refrigeration cycle apparatus 10 according to the present embodiment includes the third bypass passage 83B, the radiator 12 can be used immediately after the start of the refrigeration cycle apparatus 10, and the heating operation is quickly started. It is effective when you want.

<Embodiment 3>
A third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a circuit diagram of the refrigeration cycle apparatus according to Embodiment 3, and FIG. 8 is a circuit diagram at the time of activation of the refrigeration cycle apparatus according to Embodiment 3. In FIG. 7, the refrigerant flow during steady operation is indicated by a chain line arrow, and the refrigerant flow at startup is indicated by a solid line arrow. In FIG. 8, the starting refrigerant circuit is shown by a solid line.

  As shown in FIG. 7, the refrigeration cycle apparatus 10 according to the third embodiment is different from the refrigeration cycle apparatus 10 according to the first embodiment in that a third bypass path 83C is provided instead of the third bypass path 83A. Since the configuration is the same except for the above, the third bypass passage 83C will be described in detail below, and the description of the other portions will be omitted.

  The third bypass 83C is connected to the refrigerant circuit 16 so that the refrigerant flows directly from the outlet of the supercharger 15 to the inlet of the evaporator 14 without passing through the main compressor 11, the radiator 12, and the expander 13. The flow path. Specifically, the upstream end of the third bypass passage 83C is connected to the suction-side flow path 65 of the main compressor 11, and the downstream end is also connected to the connection flow path 63 that connects the outlet of the expander 13 and the inlet of the evaporator 14. It is connected.

  The downstream end of the first bypass passage 81 and the upstream end of the third bypass passage 83C are connected to one four-way valve 23. The four-way valve 23 is provided so as to divide the suction side flow path 65 of the main compressor 11 into an upstream side and a downstream side. By this four-way valve 23, a state in which the upstream side and the downstream side of the suction side flow path 65 are communicated (at the time of operation standby and during steady operation), and the upstream side of the suction side flow path 65 and the third bypass path 83C are connected. The flow of the refrigerant can be switched to a state (at the time of activation) where the first bypass passage 81 and the downstream side of the suction side passage 65 are communicated with each other. Therefore, during standby and steady operation, the refrigerant flows from the supercharger 15 to the main compressor 11, and at the time of start-up, the refrigerant flows directly from the supercharger 15 to the evaporator 14, and from the evaporator 14 to the main compressor. The refrigerant will flow directly to 11.

  The connection flow path 63 is provided with a check valve 26 between the outlet of the expander 13 and the connection portion at the downstream end of the third bypass path 83C. The check valve 26 prevents the refrigerant from flowing from the connection portion of the third bypass passage 83C to the outlet of the expander 13.

  In the refrigeration cycle apparatus 10, the four-way valves 21, 23 and the switching valve 22 provided at the connection portion between the refrigerant circuit 16 and the bypass paths 81, 82 </ b> A, 83 </ b> C are switched, so The refrigerant circuit 16 can be established during operation, and the activation refrigerant circuit 16A can be established when the refrigeration cycle apparatus 10 is activated.

  As shown in FIG. 7, in the refrigerant circuit 16, the refrigerant circulates in the order of the main compressor 11 → the radiator 12 → the expander 13 → the evaporator 14 → the supercharger 15 → the main compressor 11. When the refrigerant circuit 16 is effective, no refrigerant flows through the first bypass path 81, the second bypass path 82A, and the third bypass path 83C.

  As shown in FIG. 8, in the starting refrigerant circuit 16 </ b> A, the refrigerant circulates in the order of the main compressor 11 → the supercharger 15 → the evaporator 14 → the main compressor 11. In the startup refrigerant circuit 16A, no refrigerant flows through the radiator 12 and the expander 13.

[Operation of refrigeration cycle equipment]
Next, the operation of the refrigeration cycle apparatus 10 having the above configuration will be described. Note that the operation during standby and steady operation of the refrigeration cycle apparatus 10 according to the second embodiment is the same as that during the refrigeration cycle apparatus according to the first embodiment, and therefore only the operation during startup will be described here. .

  In the refrigeration cycle apparatus 10 at the time of activation, the four-way valves 21 and 23 and the switching valve 22 are switched so that the refrigerant flows through the bypass passages 81, 82A, and 83C, and the activation refrigerant circuit 16A is established. When the main compressor 11 is started, the main compressor 11 sucks the refrigerant at the inlet of the main compressor 11 from the outlet of the supercharger 15 in the starting refrigerant circuit 16A, compresses it to high temperature and high pressure, and discharges it. . That is, the main compressor 11 at the time of startup includes the suction side flow path 65, the third bypass path 83C, the connection flow path 63 between the expander 13 and the evaporator 14, the inside of the evaporator 14, the evaporator 14 and the supercharger. 15, the refrigerant in the upstream portion and the first bypass passage 81 can be sucked from the four-way valve 21. Therefore, since the refrigerant having a larger volume can be sucked compared to the discharge-side flow path 61 of the main compressor 11, a shortage of refrigerant supply to the main compressor 11 at the time of start-up can be prevented, and reliable and stable. Can be realized.

  In the starting refrigerant circuit 16A, the outlet of the main compressor 11 and the inlet of the supercharger 15 are communicated with each other by the second bypass passage 82A. Therefore, when the high-temperature and high-pressure refrigerant is discharged from the main compressor 11, Both the pressure and temperature of the refrigerant at the inlet of the supercharger 15 rise. Therefore, the refrigerant on the inlet side of the supercharger 15 has a higher pressure than the refrigerant on the outlet side, and a differential pressure is generated in the refrigerant between the inlet side and the outlet side of the supercharger 15. Here, the supercharger 15 absorbs the flow energy of the refrigerant or the expansion energy of the refrigerant and converts it into mechanical energy for rotating the power recovery shaft 17. That is, the supercharger 15 at the time of activation functions as a power recovery unit of the power recovery mechanism 18.

  Eventually, the power recovery shaft 17 is rotated by the energy recovered by the supercharger 15, and the power recovery mechanism 18 starts up independently. Here, the activated expander 13 functions as a compressor that sends the refrigerant on the inlet side of the expander 13 to the outlet side. Therefore, the self-sustained activation of the power recovery mechanism 18 detects the pressure difference or temperature difference between the refrigerant at the inlet and outlet of the expander 13, the time after the main compressor 11 is activated, or the rotational speed of the power recovery shaft 17. However, it should be noted that the pressure difference or the temperature difference becomes smaller as the inlet side of the expander 13 becomes a low temperature side and a low pressure side and approaches self-supporting.

  The medium-pressure medium-temperature refrigerant exiting the supercharger 15 flows to the evaporator 14 through the third bypass passage 83C and the connection passage 63. Here, the connection flow path 63 on the outlet side of the expander 13 has a higher pressure than the connection flow path 62 on the inlet side, but the check valve 26 prevents the refrigerant from flowing from the outlet side to the inlet side. Then, the refrigerant that has flowed through the evaporator 14 has a medium pressure and low temperature, and is sucked into the main compressor 11 again.

  When the power recovery mechanism 18 starts up in this manner, the four-way valves 21 and 23 and the switching valve 22 are switched so that the refrigerant does not flow into the bypass passages 81, 82A, and 83C, and the refrigerant starts to circulate through the refrigerant circuit 16. Transition to steady operation.

  As described above, since the refrigeration cycle apparatus 10 according to the present embodiment includes the first bypass path 81 and the third bypass path 83C, the main compressor 11 at the time of activation is added to the suction side flow path 65, The refrigerant in the flow path from the outlet of the expander 13 to the outlet of the evaporator 14 of the supercharger 15 can be sucked. Therefore, it is possible to solve the shortage of refrigerant supply to the main compressor 11 at the time of starting, and to realize a reliable and stable starting.

  Furthermore, since the radiator circuit 12A for start-up does not include the radiator 12, the refrigerant that flows through the evaporator 14 at the time of start-up has an intermediate temperature and medium pressure. Therefore, the evaporator 14 can be defrosted simultaneously by starting the refrigeration cycle apparatus 10. However, the evaporator 14 is not limited to the start-up, and the evaporator 14 can be defrosted by circulating the refrigerant through the start-up refrigerant circuit 16A.

<Embodiment 4>
A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a circuit diagram of the refrigeration cycle apparatus according to Embodiment 4, and FIG. 10 is a circuit diagram at the time of startup of the refrigeration cycle apparatus according to Embodiment 4. In FIG. 9, the flow of the refrigerant during steady operation is indicated by a chain line arrow, and the flow of the refrigerant at startup is indicated by a solid line arrow. In FIG. 10, the starting refrigerant circuit is shown by a solid line.

  As shown in FIG. 9, the refrigeration cycle apparatus 10 according to the fourth embodiment has the same configuration as the refrigeration cycle apparatus 10 according to the first embodiment except for the startup refrigerant circuit 16 </ b> A and a bypass path forming the same. is there. Therefore, the activation refrigerant circuit 16A and the bypass path forming the activation refrigerant circuit 16A will be described in detail, and descriptions of other parts will be omitted.

  The starting refrigerant circuit 16A of the refrigeration cycle apparatus 10 is formed by the refrigerant circuit 16 and the two bypass paths 81 and 82B.

  The first bypass path 81 is a flow path connected to the refrigerant circuit 16 so that the refrigerant flows from the evaporator 14 to the main compressor 11 without passing through the supercharger 15. The upstream end of the first bypass path 81 is connected to the connection flow path 64 between the evaporator 14 and the supercharger 15, and the downstream end is also connected to the suction side flow path 65 of the main compressor 11.

  The second bypass path 82 </ b> B is a flow path connected to the refrigerant circuit 16 so that the refrigerant flows from the main compressor 11 to the expander 13 without passing through the radiator 12. The upstream end of the second bypass path 82B is connected to the discharge side flow path 61 of the main compressor 11, and the downstream end is connected to the connection flow path 62 between the outlet of the radiator 12 and the inlet of the expander 13.

  A switching valve 28 is provided at a connection portion between the discharge side flow path 61 of the main compressor 11 and the upstream end of the second bypass path 82B. The switching valve 28 switches the refrigerant flow between a state in which the refrigerant flows to the refrigerant circuit 16 side (during operation standby and steady operation) and a state in which the refrigerant flows to the second bypass path 82B side (at the time of startup). Can do. Accordingly, the refrigerant flows from the main compressor 11 to the radiator 12 during operation standby and steady operation, and the refrigerant flows directly from the main compressor 11 to the expander 13 during startup.

  Further, a switching valve 27 is provided at a connection portion between the connection flow path 64 between the evaporator 14 and the supercharger 15 and the upstream end of the first bypass path 81. With this switching valve 27, the flow of the refrigerant is switched between a state in which the refrigerant flows to the refrigerant circuit 16 side (during operation standby and steady operation) and a state in which the refrigerant flows to the first bypass path 81 side (at the time of startup). Can do. Accordingly, the refrigerant flows from the evaporator 14 to the supercharger 15 during operation standby and steady operation, and the refrigerant flows directly from the evaporator 14 to the main compressor 11 during startup.

  In the refrigeration cycle apparatus 10, by switching the switching valves 27 and 28 provided at the connection portion between the refrigerant circuit 16 and the bypass paths 81 and 82 </ b> B, the refrigerant circuit 16 is switched between the standby state and the steady operation of the refrigeration cycle apparatus 10. The activation refrigerant circuit 16A can be established when the refrigeration cycle apparatus 10 is activated.

  As shown in FIG. 9, in the refrigerant circuit 16, the refrigerant circulates in the order of the main compressor 11 → the radiator 12 → the expander 13 → the evaporator 14 → the supercharger 15 → the main compressor 11. When the refrigerant can circulate through the refrigerant circuit 16, no refrigerant flows through the first bypass path 81 and the second bypass path 82B.

  As shown in FIG. 10, in the starting refrigerant circuit 16 </ b> A, the refrigerant circulates in the order of the main compressor 11 → the expander 13 → the evaporator 14 → the main compressor 11. In the startup refrigerant circuit 16A, no refrigerant flows through the radiator 12 and the supercharger 15.

[Operation of refrigeration cycle equipment]
Next, the operation of the refrigeration cycle apparatus 10 having the above configuration will be described. Note that the operation during standby and steady operation of the refrigeration cycle apparatus 10 according to Embodiment 4 is the same as that of the refrigeration cycle apparatus according to Embodiment 1, and therefore only the operation during startup will be described here. .

  In the refrigeration cycle apparatus 10 at the time of activation, the switching valves 27 and 28 are switched so that the refrigerant flows through the bypass passages 81 and 82B, and the activation refrigerant circuit 16A is established. When the main compressor 11 is started, the main compressor 11 sucks the refrigerant at the inlet of the main compressor 11 from the outlet of the expander 13 in the starting refrigerant circuit 16A, compresses it to high temperature and high pressure, and discharges it. That is, the main compressor 11 at the time of start-up includes the suction-side flow path 65, the connection flow path 63 between the expander 13 and the evaporator 14, the inside of the evaporator 14, and the connection flow path between the evaporator 14 and the supercharger 15. 64, the refrigerant in the upstream portion and the first bypass passage 81 from the switching valve 27 can be sucked. Therefore, since the refrigerant having a larger volume can be sucked compared to the discharge-side flow path 61 of the main compressor 11, a shortage of refrigerant supply to the main compressor 11 at the time of start-up can be prevented, and reliable and stable. Can be realized.

  In the starting refrigerant circuit 16A, since the outlet of the main compressor 11 and the inlet of the expander 13 are communicated with each other by the second bypass path 82B, the high-temperature and high-pressure refrigerant is discharged from the main compressor 11 to expand the refrigerant circuit 16A. Both the pressure and temperature of the refrigerant at the inlet of the machine 13 rise. On the other hand, since the main compressor 11 sucks the refrigerant in the connection flow path 63 communicating with the outlet side of the expander 13, the pressure of the refrigerant on the outlet side of the expander 13 decreases. In this way, the refrigerant pressure difference between the inlet side and the outlet side of the expander 13 increases. Eventually, when the refrigerant flow from the inlet to the outlet of the expander 13 is caused by the refrigerant pressure difference between the inlet and outlet of the expander 13, the expander 13 is activated. The activated expander 13 functions as a power recovery unit of the power recovery mechanism 18, absorbs the expansion energy of the refrigerant flowing through the expander 13, and converts it into mechanical energy for rotating the power recovery shaft 17. With this energy, the power recovery shaft 17 rotates and the power recovery mechanism 18 starts up independently.

  When the power recovery mechanism 18 starts up in this manner, the switching valves 27 and 28 are switched so that the refrigerant does not flow into the bypass passages 81 and 82B, and the refrigerant starts to circulate through the refrigerant circuit 16 and shifts to a steady operation.

  As described above, since the refrigeration cycle apparatus 10 according to the present embodiment includes the first bypass path 81, the main compressor 11 at the time of startup is expanded in addition to the suction-side flow path 65 of the main compressor 11. The refrigerant in the flow path from the outlet of the machine 13 to the outlet of the evaporator 14 can be sucked. Therefore, it is possible to solve the shortage of refrigerant supply to the main compressor 11 at the time of starting, and to realize a reliable and stable starting.

  Furthermore, since the refrigeration cycle apparatus 10 according to the present embodiment includes the second bypass passage 82B, the refrigerant discharged from the main compressor 11 at the time of start-up is directly sent to the inlet of the expander 13, and the power The recovery mechanism 18 can be started quickly. Here, since the refrigerant is sent directly from the main compressor 11 to the expander 13 without passing through the radiator 12, the refrigerant flowing out of the expander 13 is at a higher temperature than during steady operation. This high-temperature refrigerant flows through the evaporator 14, so that the evaporator 14 can be defrosted at the time of startup. However, the evaporator 14 is not limited to the start-up, and the evaporator 14 can be defrosted by circulating the refrigerant in the start-up refrigerant circuit 16A.

  The refrigeration cycle apparatus of the present invention includes a main compressor, a supercharger (or sub-compressor) that preliminarily boosts the refrigerant supplied to the main compressor, an expander in which the supercharger and a power shaft are connected, In the refrigeration cycle apparatus having the above, it is useful for solving the shortage of refrigerant supply to the main compressor at the time of start-up and realizing the reliable and rapid self-starting of the system.

1 is a circuit diagram of a refrigeration cycle apparatus according to Embodiment 1. FIG. FIG. 3 is a flowchart for starting up the refrigeration cycle apparatus according to Embodiment 1. FIG. FIG. 3 is a circuit diagram during steady operation of the refrigeration cycle apparatus according to Embodiment 1. FIG. 3 is a circuit diagram when the refrigeration cycle apparatus according to Embodiment 1 is started. FIG. 5 is a circuit diagram of a refrigeration cycle apparatus according to Embodiment 2. The circuit diagram at the time of starting of the refrigerating cycle device concerning Embodiment 2. FIG. FIG. 6 is a circuit diagram of a refrigeration cycle apparatus according to Embodiment 3. FIG. 6 is a circuit diagram at the time of starting the refrigeration cycle apparatus according to Embodiment 3. FIG. 6 is a circuit diagram of a refrigeration cycle apparatus according to Embodiment 4. FIG. 6 is a circuit diagram at the time of starting the refrigeration cycle apparatus according to Embodiment 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Refrigeration cycle apparatus 11 Main compressor 12 Radiator 13 Expander 14 Evaporator 15 Supercharger 16 Refrigerant circuit 16A Start-up refrigerant circuit 17 Power recovery shaft 18 Power recovery unit 19 Sealed container 21, 23 Four-way valve 22, 27, 28 Switching valve 31 Control device 32 Operating tool 33 Start detection means 61 Discharge side flow path 65 Suction side flow path 81 First bypass path 82A, 82B Second bypass path 83A, 83B, 83C Third bypass path

Claims (13)

A compressor that compresses the refrigerant; a radiator that dissipates the refrigerant compressed by the compressor; an expander that recovers power from the refrigerant by expanding the refrigerant dissipated by the radiator; and evaporates the refrigerant expanded by the expander A first refrigerant circuit comprising: an evaporator to be connected; and a supercharger that pressurizes the refrigerant evaporated by the evaporator and sends the refrigerant to the compressor in order through a connection flow path;
A power recovery mechanism having a power recovery shaft for connecting the expander and the supercharger so that the supercharger is driven by the power recovered by the expander, the supercharger, and the expander; ,
A first bypass path connected to the first refrigerant circuit so that the refrigerant flows from the outlet of the evaporator to the inlet of the compressor without passing through the supercharger;
A second bypass path connected to the first refrigerant circuit so that the refrigerant flows from the outlet of the compressor to the inlet of the power recovery mechanism without passing through either the radiator or the evaporator;
A flow path switching mechanism for switching a refrigerant flow between a state in which the refrigerant circulates in the first refrigerant circuit and a state in which the refrigerant circulates in a second refrigerant circuit including the first bypass path and the second bypass path. Have
Refrigeration cycle equipment. The upstream end of the second bypass path is connected to a connection flow path between the outlet of the compressor and the inlet of the radiator, and the downstream end of the second bypass path is an outlet of the evaporator and an inlet of the supercharger Connected to the connection flow path,
The refrigeration cycle apparatus according to claim 1. Connected to the first refrigerant circuit so that the refrigerant flows from the outlet of the supercharger without passing through the compressor to a portion from the outlet of the compressor of the first refrigerant circuit to the inlet of the evaporator, A third bypass path included in the second refrigerant circuit,
The refrigeration cycle apparatus according to claim 2. The upstream end of the third bypass path is connected to a connection flow path between the outlet of the supercharger and the inlet of the compressor, and the downstream end of the third bypass path is an outlet of the radiator and the inlet of the expander Connected to the connection flow path,
The refrigeration cycle apparatus according to claim 3. The upstream end of the third bypass path is connected to a connection flow path between the outlet of the supercharger and the inlet of the compressor, and the downstream end of the third bypass path is an outlet of the compressor and an inlet of the radiator. Connected to the connection flow path,
The refrigeration cycle apparatus according to claim 3. The upstream end of the third bypass passage is connected to a connection flow path between the outlet of the supercharger and the inlet of the compressor, and the downstream end of the third bypass passage is an outlet of the expander and an inlet of the evaporator Connected to the connection flow path,
A check valve as the flow path switching mechanism is provided between the outlet of the expander of the first refrigerant circuit and the downstream end of the third bypass path.
The refrigeration cycle apparatus according to claim 3. In the connection flow path between the outlet of the evaporator and the inlet of the supercharger, a first flow path switching device that divides the connection flow path into an upstream side and a downstream side as the flow path switching mechanism,
The first flow path switch has a state in which the upstream end of the first bypass path and the downstream end of the second bypass path communicate with each other, and the upstream side and the downstream side of the connection flow path communicate with each other. The upstream side of the path and the upstream end of the first bypass path are in communication with each other, and the downstream side of the connection flow path and the downstream end of the second bypass path are in communication with each other.
The refrigeration cycle apparatus according to any one of claims 2 to 6. The first flow path switch is a four-way valve,
The refrigeration cycle apparatus according to claim 7. A connection flow path between the outlet of the supercharger and the inlet of the compressor includes a second flow path switching unit that divides the connection flow path into an upstream side and a downstream side as the flow path switching mechanism,
The second flow path switch is in a state where the downstream end of the first bypass path and the upstream end of the third bypass path communicate with each other and the upstream side and the downstream side of the connection flow path communicate with each other. The upstream side of the flow path and the upstream end of the third bypass path communicate with each other, and the downstream side of the connection flow path and the downstream end of the first bypass path are configured to be switched.
The refrigeration cycle apparatus according to any one of claims 3 to 8. The second flow path switch is a four-way valve,
The refrigeration cycle apparatus according to claim 9. The upstream end of the second bypass passage is connected to a connecting flow path between the outlet of the compressor and the inlet of the radiator, and the downstream end is connected to a connecting flow path between the outlet of the radiator and the inlet of the expander. It is connected,
The refrigeration cycle apparatus according to claim 1. A switching valve for switching a refrigerant flow between the first refrigerant circuit side and the first bypass path side is provided as a flow path switching mechanism at a connection portion between the upstream end of the first bypass path and the first refrigerant circuit. ,
The refrigeration cycle apparatus according to claim 11. A switching valve for switching a refrigerant flow between the first refrigerant circuit side and the second bypass path side is provided as a flow path switching mechanism at a connection portion between the upstream end of the second bypass path and the first refrigerant circuit. ,
The refrigeration cycle apparatus according to any one of claims 1 to 12.

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