JPWO2018198220A1 - Refrigeration system - Google Patents

Abstract

The refrigeration system is a compressor that compresses a refrigerant and discharges it with the refrigerator oil, an oil separator that separates the refrigerant discharged from the compressor and the refrigerator oil, and a refrigerant separated by the oil separator and the heat source medium Between the refrigerant flowing from the refrigerator unit through the first main pipe and the utilization medium, which is connected to the refrigerator unit with the first main pipe and the refrigerator unit having the heat source side heat exchanger for performing heat exchange in A cooler unit having a use-side heat exchanger that performs heat exchange, a cooler unit and a refrigerator unit are connected by a second main pipe, and are also connected by a refrigerator unit and first and second oil pipes, And a heat storage unit having a heat storage tank for storing, as a heat storage material, refrigerator oil separated by the oil separator, which flows in from the refrigerator unit via the first oil pipe.

Description

  The present invention relates to a refrigeration system that performs hot gas defrosting using a heat storage tank.

  Conventionally, in a hot gas defrosting type refrigeration system using a heat storage tank, high temperature refrigerant discharged from the compressor flows into the heat exchanger in the heat storage tank in the heat storage unit during cooling operation, and heat storage in the heat storage tank Heat the material. On the other hand, during the hot gas defrosting operation, the refrigerant flowing out of the cooler unit re-evaporates by exchanging heat with the heated heat storage material in the heat storage tank, and returns to the compressor. As a result, the defrosting capability of the refrigeration system is improved, and liquid return of the refrigerant to the compressor is prevented.

  For example, Patent Document 1 describes a hot gas defrosting type refrigeration system using such a heat storage tank. In the refrigeration apparatus described in Patent Document 1, during the cooling operation, the refrigerant discharged from the compressor flows into the heat exchanger in the heat storage tank, and heats the heat storage material in the heat storage tank. Thereafter, the refrigerant flows into the condenser and condenses by heat exchange, and flows into the cooler of the cooler unit and evaporates by heat exchange. Then, the refrigerant returns to the compressor without flowing into the heat storage tank by the four-way valve in the heat storage unit after evaporation.

  On the other hand, during the defrosting operation, the refrigerant discharged from the compressor flows into the cooler unit without flowing into the heat storage tank, passes through the cooler, and flows into the heat storage unit. Then, the refrigerant flowing into the heat storage unit flows into the heat exchanger in the heat storage tank, re-evaporates by exchanging heat with the heat storage material, and then flows out from the heat storage unit. The refrigerant flowing out of the heat storage unit flows into the refrigerator unit and returns to the compressor.

  As described above, in the hot gas defrosting type refrigeration system using the heat storage tank, the refrigerant in a wet state is re-evaporated by the heat storage unit. Therefore, the latent heat of the refrigerant can be used at the time of defrosting, and high defrosting efficiency can be obtained as compared with the simple hot gas defrosting method.

Japanese Patent Application Laid-Open No. 59-112161

  However, in the refrigeration apparatus described in Patent Document 1, when connecting the heat storage unit to another unit, the piping at three locations connected to the circuit on the high pressure side and the two piping connected to the circuit for re-evaporation A total of 5 pipings are required. Therefore, there existed a subject that the workability of installing a freezing apparatus was bad.

  Moreover, it is common to use ethylene glycol or nybrine (nybrine is a registered trademark) etc. for a heat storage material. In such a case, for example, when a crack occurs in the heat storage tank and an abnormality occurs such that the heat storage material flows into the refrigeration cycle, it becomes necessary to recover and refill all the refrigerant and the refrigerator oil. I will. Furthermore, in some cases, cleaning within the refrigeration cycle is required. Therefore, while taking time and effort for repair, the quality of a freezing apparatus will fall.

  This invention is made in view of the subject in the said prior art, Comprising: While improving a workability, it aims at providing the freezing apparatus which can suppress the fall of quality.

  The refrigeration apparatus according to the present invention comprises a compressor which compresses a refrigerant and discharges it together with a refrigerator oil, an oil separator which separates the refrigerant discharged from the compressor and the refrigerator oil, and a separator separated by the oil separator A refrigerator unit having a heat source side heat exchanger for performing heat exchange between the refrigerant and a heat source medium, and the refrigerator unit and a first main pipe are connected, and the refrigerator unit is connected via the first main pipe A cooler unit having a utilization side heat exchanger for performing heat exchange between the refrigerant flowing from the pipe and the utilization medium, the cooler unit and the refrigerator unit being connected by a second main pipe, and the refrigerator A heat storage tank connected as a heat storage material to the unit and connected by first and second oil pipes and flowing from the refrigerator unit through the first oil pipe and separated by the oil separator as a heat storage material Heat storage unit with It is intended and a Tsu door.

  As described above, according to the present invention, the heat storage material is connected to the heat storage unit by the first and second main pipes and the refrigerator unit and the cooler unit by the first and second oil pipes, and stored in the heat storage tank. By using a refrigerating machine oil, it is possible to improve the workability and to suppress the deterioration of the quality.

FIG. 1 is a block diagram showing an example of the configuration of a refrigeration apparatus according to Embodiment 1; It is the schematic for demonstrating the flow of the refrigerant | coolant at the time of cooling operation, and refrigeration oil in the freezing apparatus of FIG. It is the schematic for demonstrating the flow of the refrigerant | coolant at the time of a defrost driving | operation in the freezing apparatus of FIG. 1, and refrigerator oil. It is a flowchart which shows an example of the process for controlling the flow of refrigeration oil at the time of cooling operation in the freezing apparatus of FIG. It is a flowchart which shows an example of the process for controlling the flow of refrigeration oil at the time of a defrost operation in the freezing apparatus 1 of FIG. FIG. 6 is a block diagram showing an example of the configuration of a refrigeration apparatus according to a modification of the first embodiment.

Embodiment 1
Hereinafter, a refrigeration apparatus according to Embodiment 1 of the present invention will be described. The refrigeration apparatus according to the first embodiment is a vapor compression type refrigeration cycle apparatus, and performs, for example, a cooling operation such as a food storage or ice making. Further, the refrigeration system performs a defrosting operation for defrosting the use-side heat exchanger provided on the cooling side.

[Configuration of refrigeration system]
FIG. 1 is a block diagram showing an example of the configuration of the refrigeration system 1 according to the first embodiment. As shown in FIG. 1, the refrigeration system 1 includes a refrigerator unit 10, a cooler unit 20, a heat storage unit 30, a fuel supply circuit 40, and a control device 50. In the refrigeration system 1, a refrigeration cycle is formed by connecting a refrigeration unit 10, a cooler unit 20, and a heat storage unit 30 with a refrigerant pipe and an oil pipe. In addition, although the case where one cooler unit 20 is connected is shown in this example, it is not restricted to this, For example, several cooler units 20 may be connected.

(Refrigerator unit)
The refrigerator unit 10 is a unit on the heat source side, and is installed, for example, outdoors or in a machine room of a building. The refrigerator unit 10 is connected to the cooler unit 20 by a single first main pipe 2. Further, the refrigerator unit 10 is connected to the heat storage unit 30 by one second main pipe 3 and two pipes in the oil supply circuit 40. The refrigerator unit 10 includes the compressor 11, the oil separator 12, the heat source side heat exchanger 13, the accumulator 14, the first liquid switching device 15 and the first hot gas switching device 16, and part of the fuel supply circuit 40. Have.

  The compressor 11 sucks a low-temperature low-pressure refrigerant, compresses the refrigerant, and discharges the high-temperature high-pressure gas refrigerant. There are various compressors such as a rotary system, a scroll system, or a screw system as the compressor 11, but in the first embodiment, for example, a screw system in which the amount of outflow of refrigeration oil flowing out of the compressor 11 is larger It is preferable to use a compressor or the like.

  In addition, as the compressor 11, for example, an inverter compressor capable of controlling the capacity, which is the refrigerant delivery amount per unit time, can be used by arbitrarily changing the drive frequency. Moreover, it is not restricted to this, For example, the driving speed by a commercial power source can also use the constant speed compressor with a fixed frequency. Furthermore, in this example, although the case where one compressor 11 is provided is described, the present invention is not limited thereto. For example, a plurality of compressors 11 may be connected in parallel and used.

  The oil separator 12 is provided with an inlet through which a gas refrigerant containing refrigerator oil discharged from the compressor 11 flows, a refrigerant outlet through which the gas refrigerant flows out, and an oil outlet through which the refrigerator oil flows out. . The oil separator 12 has an inlet connected to the discharge side of the compressor 11.

  The oil separator 12 separates a gas refrigerant containing refrigeration oil discharged from the compressor 11 into a refrigerant and refrigeration oil. As the oil separator 12, for example, a cyclone type or a demister type may be used.

  The heat source side heat exchanger 13 is connected to the refrigerant outlet side of the oil separator 12 at the upstream side, and is connected to the first main pipe 2 at the downstream side. The heat source side heat exchanger 13 receives a high temperature and high pressure gas refrigerant in the cooling operation, and performs heat exchange between the heat source medium such as air supplied by a fan (not shown) and the like and the refrigerant. Specifically, the heat source side heat exchanger 13 functions as a condenser that radiates the heat of the refrigerant to the heat source medium and condenses the refrigerant during the cooling operation.

  As the heat source side heat exchanger 13, for example, a fin and tube type heat exchanger of cross fin type, a water cooled type heat exchanger of shell and tube type, or a plate type heat exchanger of brazing plate type can be used. .

  The accumulator 14 is provided on the suction side of the compressor 11, and a refrigerant returning from a heat storage unit 30 described later flows in. The accumulator 14 stores surplus refrigerant and the like with respect to transient operation changes. By installing the accumulator 14, the internal volume of the accumulator 14 capable of preventing liquid compression due to liquid return to the compressor 11 can be appropriately determined according to the unit volume, the volume of the cooler unit 20, etc. .

  The accumulator 14 is not necessarily installed in the refrigerator unit 10. When performing the defrosting operation by the hot gas, since the hot gas passes through the pipe cooled to the temperature corresponding to the utilization side at the start of the defrosting operation, the refrigerant is easily condensed, and the compressor 11 The possibility of liquid compression due to liquid return increases. Therefore, although it is desirable to install the accumulator 14, as described later, when the refrigeration apparatus 1 has the ability to reliably evaporate the refrigerant in the heat storage tank 32, it is necessary to install the accumulator 14 There is no. The necessity of the accumulator 14 may be determined in accordance with the test or the local environment.

  The first liquid switching device 15 is, for example, an electromagnetic valve, and is provided in a pipe between the downstream side of the heat source side heat exchanger 13 and the first main pipe 2. The first liquid switching device 15 is normally in the "open" state during the cooling operation, and in the "closed" state during the pump-down operation, the defrosting operation, and the stop.

  The liquid refrigerant in the pipe can be recovered to the side of the refrigerator unit 10 by performing the pump-down operation with the first liquid opening / closing device 15 in the “closed” state before the start of the defrosting operation. Thereby, the first main pipe 2 can be shared for the cooling operation and the defrosting operation.

  The first hot gas switching device 16 is, for example, a solenoid valve, and is provided in a hot gas pipe connected between the refrigerant outlet of the oil separator 12 and the downstream side of the first liquid switching device 15 . The first hot gas switching device 16 is normally in the “closed” state during the cooling operation, and in the “open” state during the defrosting operation.

  In the example illustrated in FIG. 1, the compressor 11 and the heat source side heat exchanger 13 are described as separate bodies, but the invention is not limited thereto. For example, the compressor 11 and the heat source side heat exchanger 13 are integrated. May be configured. Moreover, various methods, such as an air cooling system or a water cooling system, can be applied also to the system of heat exchange. Furthermore, as the refrigerator unit 10, for example, not shown components such as a receiver, a subcooling heat exchanger, and an intermediate injection circuit may be provided as necessary. For example, in the case of the refrigerator unit 10 provided with an intermediate injection circuit, a compressor provided with an intermediate injection function is used as the compressor 11.

(Cooler unit)
The cooler unit 20 is a unit on the use side, and is installed, for example, on a ceiling, floor or wall in a cold storage. The cooler unit 20 is connected to the refrigerator unit 10 by one first main pipe 2. Further, the cooler unit 20 is connected to the heat storage unit 30 by one second main pipe 3. The cooler unit 20 includes a use-side heat exchanger 21, a first pressure reducing device 22, a second liquid switching device 23 and a second hot gas switching device 24.

  The upstream side of the use side heat exchanger 21 is connected to the first main pipe 2, and the downstream side is connected to the second main pipe 3. In the use side heat exchanger 21, a low temperature low pressure gas-liquid two-phase refrigerant flows in during the cooling operation, and heat exchange is performed between the use medium such as air supplied by a fan (not shown) and the like and the refrigerant. Specifically, the use-side heat exchanger 21 functions as an evaporator that evaporates the refrigerant during the cooling operation and cools air or the like by the heat of vaporization at that time. As the use side heat exchanger 21, for example, a plate fin tube type can be used.

  The first pressure reducing device 22 is connected between the first main pipe 2 and the upstream side of the use side heat exchanger 21. The first pressure reducing device 22 is, for example, an expansion valve, which decompresses and expands a high-pressure liquid refrigerant to form a low-pressure gas-liquid two-phase refrigerant. The first pressure reducing device 22 is controlled by the control device 50 described later so that the refrigerant outlet temperature of the use side heat exchanger 21 becomes optimal. The first pressure reducing device 22 is constituted by, for example, a valve such as an electronic expansion valve capable of controlling the opening degree. Further, the first pressure reducing device 22 is not limited to this, and, for example, a temperature type may be used.

  The second liquid on-off device 23 is, for example, a solenoid valve, and is disposed between the first main pipe 2 and the upstream side of the use side heat exchanger 21 and on the upstream side of the first pressure reducing device 22. It is connected in series with the pressure reducing device 22. The second liquid opening / closing device 23 is normally in the “open” state during the cooling operation and in the “closed” state during the defrosting operation.

  The second hot gas switching device 24 is, for example, a solenoid valve, and is between the first main pipe 2 and the upstream side of the use side heat exchanger 21 and includes the first pressure reducing device 22 and the second liquid switching. It is connected in parallel with the device 23. The second hot gas switching device 24 is normally in the “closed” state during the cooling operation and in the “open” state during the defrosting operation.

(Heat storage unit)
The heat storage unit 30 operates as a thermobank that stores heat with warm refrigeration oil during cooling operation and utilizes the heat to evaporate the refrigerant during defrosting operation. The heat storage unit 30 is provided between the refrigerator unit 10 and the cooler unit 20. The heat storage unit 30 is connected to the cooler unit 20 by one second main pipe 3. Further, the heat storage unit 30 is connected to the refrigerator unit 10 through two pipes in one second main pipe 3 and the oil supply circuit 40. The heat storage unit 30 includes a refrigerant flow switching device 31, a heat storage tank 32, an auxiliary heater 33 and a temperature sensor 34, a second pressure reducing device 35, and a part of a refueling circuit 40.

  The refrigerant flow switching device 31 is provided in the second main pipe 3 connecting the cooler unit 20 and the heat storage unit 30, and the heat storage unit 30 and the refrigerator unit 10. The refrigerant flow switching device 31 is, for example, a four-way valve, and switches the flow path of the refrigerant during the cooling operation and the defrosting operation by switching the flow direction of the refrigerant. Specifically, the refrigerant flow switching device 31 switches the flow paths so that the inflowing refrigerant does not flow into the heat storage tank 32 described later during the cooling operation, and flows into the heat storage tank 32 during the defrosting operation. .

  The second decompression device 35 is, for example, a linear expansion valve, and decompresses the refrigerant from the cooler unit 20 flowing into the heat storage tank 32 so as to be easily re-evaporated. As described above, by providing the second decompression device 35, even when the heat of defrosting is used in the cooler unit 20 so that the hot gas is completely liquefied, the hot gas is re-evaporated by the heat storage side heat exchanger 32a. It can be made easy to do. Therefore, defrosting efficiency can be improved.

  However, if the refrigerant flowing out of the cooler unit 20 is in a gas-liquid two-phase state, it tends to evaporate in the heat storage side heat exchanger 32a. Therefore, if the refrigerant flowing into the heat storage tank 32 can be brought into a gas-liquid two-phase state by the amount of frost formation or operation control of the use-side heat exchanger 21, the second pressure reducing device 35 is not installed. Good.

  The heat storage tank 32 is for storing refrigeration oil as a heat storage material, and has a heat storage side heat exchanger 32a inside. A refueling circuit 40 to be described later is connected to the heat storage tank 32 to store or circulate refrigeration oil. The heat storage tank 32 can suppress the fall of the temperature of the refrigerator oil stored during cooling operation by covering the outer side with a heat insulating material, for example.

  The heat storage side heat exchanger 32a performs heat exchange between the refrigerant flowing in during the defrosting operation and the refrigeration oil stored in the heat storage tank 32, and functions as an evaporator for evaporating the refrigerant. As the heat storage side heat exchanger 32a, for example, a plate fin tube type may be used, or a pipe through which the refrigerant flows may be disposed in the heat storage tank 32. By using a plate type heat exchanger, the heat exchange performance can be improved, and the total amount of refrigeration oil can be reduced, so that the cost can be reduced.

  The heat storage side heat exchanger 32a is not limited to this, and for example, a shell and tube type can be used. In this case, heat exchange performance can be improved by using the shell side as the refrigerator oil and the tube side as the refrigerant.

  The auxiliary heater 33 is used as an auxiliary heat source when the temperature of the refrigerator oil in the heat storage tank 32 is low. For example, when the defrosting operation is started in a state where the outside air temperature is low and the temperature of the refrigerating machine oil in the heat storage tank 32 has not risen to a preset temperature, the auxiliary heater 33 freezes the heat storage tank 32 Heat the machine oil.

  In addition, for example, by controlling the temperature of the refrigeration oil returned to the compressor 11 as described later, the temperature of the refrigeration oil in the heat storage tank 32 can be secured, and the defrosting performance can be secured. In the case, the auxiliary heater 33 may not be provided.

  The temperature sensor 34 detects the temperature of the refrigerator oil in the heat storage tank 32, and supplies the detection result to the control device 50. As the temperature sensor 34, for example, a thermistor or a resistance temperature detector such as PT 100 Ω can be used.

(Refueling circuit)
The oil supply circuit 40 is for returning the refrigerator oil separated by the oil separator 12 of the refrigerator unit 10 to the compressor 11. The oil supply circuit 40 is for storing or circulating refrigeration oil as a heat storage material in the heat storage tank 32 of the heat storage unit 30. The oil supply circuit 40 is provided in the refrigerator unit 10 and the heat storage unit 30, and the oil cooler 41, the first oil supply bypass opening / closing device 42, the second oil supply bypass opening / closing device 43, the first heat storage circuit opening / closing device 44 And a second heat storage circuit switching device 45.

  The oil cooler 41 is connected on the upstream side to the oil outlet of the oil separator 12 and on the downstream side to the oil outlet of the compressor 11. The oil cooler 41 cools the inflowing refrigerator oil. As the oil cooler 41, for example, a plate fin tube heat exchanger can be used when the refrigerator unit 10 is air cooled, and a shell and tube heat exchanger can be used when the refrigerator unit 10 is water cooled. Can. Also, for example, when the refrigerator unit 10 performs refrigerant cooling with the intermediate refrigerant, a plate heat exchanger can be used.

  The first oil supply bypass opening / closing device 42 is, for example, a solenoid valve, and is connected in parallel to the oil cooler 41. In the oil supply circuit 40, when the refrigeration oil is cooled, the first oil supply bypass opening / closing device 42 is in the “closed” state, and when the refrigeration oil is not cooled, the first oil supply bypass opening / closing device 42 is “opened”. It will be in the state.

  The second oil supply bypass opening / closing device 43 is provided between the oil outlet of the oil separator 12 and the upstream side of the oil cooler 41 and the first oil supply bypass opening / closing device 42. The second refueling bypass opening / closing device 43 is, for example, a solenoid valve, and is provided to switch the flow path of the refrigeration oil. The second oil supply bypass opening / closing device 43 is normally in the “closed” state during the cooling operation, and in the “open” state during the defrosting operation.

  The first oil pipe 4 connected to the heat storage tank 32 and provided with a first heat storage circuit opening / closing device 44 described later is connected to the upstream side of the second oil supply bypass opening / closing device 43, and is connected downstream. A second oil pipe 5 connected to the heat storage tank 32 and provided with a second heat storage circuit opening / closing device 45 described later is connected. Then, the second oil supply bypass opening / closing device 43 switches the flow path of the refrigeration oil in cooperation with the first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device 45.

  The first heat storage circuit opening / closing device 44 is, for example, a solenoid valve, and is provided in the first oil pipe 4 connecting the upstream side of the second oil supply bypass opening / closing device 43 and the heat storage tank 32. The second heat storage circuit opening / closing device 45 is, for example, a solenoid valve, and is provided in a second oil pipe 5 that connects between the heat storage tank 32 and the downstream side of the second oil supply bypass opening / closing device 43.

  The first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device 45 circulate and block refrigeration oil to the heat storage tank 32 in accordance with the open / close state. The first heat storage circuit switching device 44 and the second heat storage circuit switching device 45 are normally in the "open" state during the cooling operation, and in the "closed" state during the defrosting operation.

  In addition, even during the cooling operation, for example, when there is a possibility that refrigeration oil having a low temperature may circulate through the heat storage tank 32 due to factors such as a low outside air temperature, the temperature of the refrigerator oil in the heat storage tank 32 is It may be considered that it is judged that sufficient security has been secured. In such a case, the first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device 45 are in the “closed” state, and block the flow of the refrigerator oil into the heat storage tank 32.

(Control device)
The control device 50 is configured of, for example, software executed on an arithmetic device such as a microcomputer and a CPU (Central Processing Unit), and hardware such as a circuit device for realizing various functions. The control device 50 controls the overall operation of the refrigeration system 1 based on, for example, settings made by a user operation on a remote controller (not shown) and various information received from each unit of the refrigeration system 1.

  In the first embodiment, for example, based on the temperature of the refrigerator oil in heat storage tank 32 detected by temperature sensor 34 (hereinafter referred to as “temperature in heat storage tank” as appropriate), control device 50 Control the open / close state of each switching device provided in each part. In addition, the control device 50 includes a storage unit (not shown), and various setting values and setting times and the like regarding various temperatures used when controlling the respective switching devices are stored in advance.

  Although not shown, a plurality of sensors are mounted on the refrigerator unit 10 and the cooler unit 20 in the refrigerator 1. For example, a high pressure sensor is provided on the discharge side of the compressor 11, and a low pressure sensor is provided on the suction side. Further, the heat source side heat exchanger 13 is provided with an outside air temperature sensor or a water temperature sensor. The control device 50 controls each part so that the operation of the refrigeration system 1 becomes optimal, using the sensor values detected by such various sensors as control parameters.

[Operation of refrigeration system]
Next, the operation of the refrigerating apparatus 1 having the above configuration will be described. The refrigeration system 1 according to the first embodiment performs a cooling operation for cooling a use medium in a space such as a cold storage warehouse and a defrost operation for removing frost formation on the use side heat exchanger 21 in the cooler unit 20. . Hereinafter, flows of the refrigerant and the refrigerator oil in the cooling operation and the defrosting operation in the refrigeration apparatus 1 will be described.

(Cooling operation)
FIG. 2 is a schematic view for explaining the flows of the refrigerant and the refrigerator oil at the time of the cooling operation in the refrigeration system 1 of FIG. During the cooling operation, the refrigerant flow switching device 31 and the respective opening and closing devices are set to the state shown in FIG. Here, in each of the opening and closing devices, the white outline indicates that it is in the "open" state, and the black out state indicates that it is in the "closed" state. Further, in FIG. 2, solid arrows indicate the flow of refrigerant, and dotted arrows indicate the flow of refrigeration oil. Note that the open / close state of each open / close device is not uniquely determined by the operation mode, and is appropriately controlled according to the temperature state of the refrigerator oil and the like.

  The low-temperature low-pressure refrigerant is compressed by the compressor 11 to be a high-temperature high-pressure gas refrigerant, and is discharged together with the refrigerator oil. The high temperature and high pressure gas refrigerant and the refrigerator oil discharged from the compressor 11 flow into the inlet of the oil separator 12. The high temperature and high pressure gas refrigerant and the refrigerator oil are separated into the gas refrigerant and the refrigerator oil in the oil separator 12, the gas refrigerant flows out from the refrigerant outlet, and the refrigerator oil flows out from the oil outlet.

  The high temperature / high pressure gas refrigerant flowing out of the oil separator 12 flows into the heat source side heat exchanger 13, exchanges heat with the heat source medium, condenses while radiating heat, and becomes a high pressure liquid refrigerant as the heat source side heat exchanger 13 Flow out of The high-pressure liquid refrigerant flowing out of the heat source side heat exchanger 13 flows out of the refrigerator unit 10 and flows into the cooler unit 20 via the first main pipe 2.

  The high-pressure liquid refrigerant flowing into the cooler unit 20 is decompressed by the first pressure reducing device 22 to become a low-temperature low-pressure gas-liquid two-phase refrigerant, and flows into the use side heat exchanger 21. The low-temperature low-pressure gas-liquid two-phase refrigerant flowing into the use-side heat exchanger 21 exchanges heat with the use medium, absorbs heat and evaporates to cool room air, and becomes a low-temperature low-pressure gas refrigerant. Flow out of the vessel 21. The low-temperature low-pressure gas refrigerant flowing out of the use side heat exchanger 21 flows out of the cooler unit 20 and flows into the heat storage unit 30 via the second main pipe 3.

  The low-temperature low-pressure gas refrigerant flowing into the heat storage unit 30 flows out from the heat storage unit 30 without flowing into the heat storage tank 32 via the refrigerant flow switching device 31. The low-temperature low-pressure gas refrigerant flowing out of the heat storage unit 30 flows into the refrigerator unit 10 via the second main pipe 3.

  The low-temperature low-pressure gas refrigerant that has flowed into the refrigerator unit 10 passes through the accumulator 14 and is drawn into the compressor 11.

  On the other hand, the refrigeration oil that has flowed out of the oil separator 12 flows out of the refrigeration unit 10 through the first oil pipe 4 because the second oil supply bypass opening / closing device 43 is in the “closed” state, and the heat is accumulated. Flow into unit 30. At this time, the refrigeration oil is heated to a temperature equivalent to the discharge temperature of the compressor 11.

  The refrigeration oil that has flowed into the heat storage unit 30 flows into the heat storage tank 32, circulates, and flows out from the heat storage tank 32. Then, the refrigerator oil that has flowed out of the heat storage tank 32 flows out of the heat storage unit 30 and flows into the refrigerator unit 10 via the second oil pipe 5. The refrigeration oil flowing into the refrigeration unit 10 flows into the oil cooler 41 and is cooled, and then returned to the compressor 11.

  In this example, since the first oil supply bypass opening / closing device 42 is in the “closed” state, the refrigeration oil is cooled by the oil cooler 41 and returned to the compressor 11. On the other hand, when refrigeration oil is not required to be cooled, the first oil supply bypass opening / closing device 42 is brought into the "open" state. Then, the refrigeration oil is returned to the compressor 11 as it is via the first oil supply bypass opening / closing device 42 without flowing into the oil cooler 41 due to the pressure drop of the oil cooler 41. Whether or not such refrigeration oil needs to be cooled is determined by the control device 50, and the open / close state of the first oil supply bypass opening / closing device 42 is controlled according to the determination result.

(Defrosting operation)
FIG. 3 is a schematic view for explaining the flows of the refrigerant and the refrigeration oil during the defrosting operation in the refrigeration system 1 of FIG. 1. During the defrosting operation, the refrigerant flow switching device 31 and the respective opening / closing devices are set to the state shown in FIG. In FIG. 3, solid arrows indicate the flow of refrigerant, and dotted arrows indicate the flow of refrigeration oil.

  The low-temperature low-pressure refrigerant is compressed by the compressor 11 to be a high-temperature high-pressure gas refrigerant, and is discharged together with the refrigerator oil. The high temperature and high pressure gas refrigerant and the refrigerator oil discharged from the compressor 11 flow into the inlet of the oil separator 12. The high temperature and high pressure gas refrigerant and the refrigerator oil are separated into the gas refrigerant and the refrigerator oil in the oil separator 12, the gas refrigerant flows out from the refrigerant outlet, and the refrigerator oil flows out from the oil outlet.

  The high temperature and high pressure gas refrigerant flowing out of the oil separator 12 flows out of the refrigerator unit 10 through the hot gas pipe provided with the first hot gas switching device 16. The high-temperature high-pressure gas refrigerant flowing out of the refrigerator unit 10 flows into the cooler unit 20 via the first main pipe 2.

  The high-temperature and high-pressure gas refrigerant that has flowed into the cooler unit 20 flows into the use-side heat exchanger 21 via the second hot gas switching device 24. The high-temperature and high-pressure gas refrigerant that has flowed into the use-side heat exchanger 21 performs defrosting by the hot gas and flows out of the use-side heat exchanger 21. The refrigerant that has flowed out of the use side heat exchanger 21 flows out of the cooler unit 20 and flows into the heat storage unit 30 via the second main pipe 3.

  The refrigerant that has flowed into the heat storage unit 30 flows into the heat storage tank 32 via the refrigerant flow switching device 31 and the second pressure reducing device 35. The refrigerant flowing into the heat storage tank 32 evaporates by exchanging heat with the refrigerator oil by the heat storage side heat exchanger 32 a in the heat storage tank 32, and flows out from the heat storage tank 32. The refrigerant flowing out of the heat storage tank 32 flows out of the heat storage unit 30 via the refrigerant flow path switching device 31. The refrigerant flowing out of the heat storage unit 30 flows into the refrigerator unit 10 via the second main pipe 3. The refrigerant flowing into the refrigerator unit 10 passes through the accumulator 14 and is drawn into the compressor 11.

  On the other hand, the refrigeration oil that has flowed out of the oil separator 12 has both the first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device 45 in the heat storage unit 30 closed. It does not flow into 30 and is returned to the compressor 11 via the second oil supply bypass opening / closing device 43. Here, the refrigeration oil is basically returned to the compressor 11 without the oil cooler 41 in order to secure the amount of hot gas heat. In addition, when the temperature of refrigeration oil becomes high and the discharge temperature in the compressor 11 is protected, the refrigeration oil may be cooled by the oil cooler 41.

(Control processing of refrigeration oil flow)
Next, processing for controlling the flow of refrigeration oil in the refrigeration apparatus 1 according to Embodiment 1 will be described. FIG. 4 is a flow chart showing an example of processing for controlling the flow of refrigeration oil in the cooling operation in the refrigeration system 1 of FIG. FIG. 5 is a flow chart showing an example of processing for controlling the flow of refrigeration oil in the defrosting operation in the refrigeration system 1 of FIG. 1.

(During cooling operation)
First, processing at the time of cooling operation will be described with reference to FIG. When the cooling operation is started, in step S1, the controller 50 determines whether the temperature in the heat storage tank, which is the temperature of the refrigerator oil in the heat storage tank 32 detected by the temperature sensor 34, is equal to or higher than the set temperature. Do. If it is determined that the temperature in the heat storage tank is less than the set temperature (step S1; No), the process proceeds to step S2.

  In step S2, the control device 50 sets the second oil supply bypass opening / closing device 43 in the “closed” state, and also opens each of the first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device 45 Set to As a result, in the oil supply circuit 40, the heated refrigerator oil that has flowed out of the oil separator 12 circulates in the heat storage tank 32.

In step S3, the control device 50 measures an elapsed time from the process of step S2. When the measured time has elapsed by T ₁ preset time, the control unit 50, in step S4, it is determined whether the detected heat storage tank temperature by the temperature sensor 34 is set temperature or higher. If it is determined that the temperature in the heat storage tank is less than the set temperature (step S4; No), the process proceeds to step S5, and the control device 50 places the first oil supply bypass opening / closing device 42 in the "open" state. Set Thus, the refrigeration oil flowing out of the heat storage tank 32 is returned to the compressor 11 as it is without being dissipated by the oil cooler 41.

  On the other hand, if it is determined in step S1 that the temperature in the heat storage tank is higher than the set temperature (step S1; Yes), and if it is determined in step S4 that the temperature in the heat storage tank is higher than the set temperature (step S4) Yes), the control device 50 determines that the refrigerator oil in the heat storage tank 32 has reached a sufficient temperature. Then, a series of processing ends. The process shown in FIG. 4 is cyclically repeated at preset times during the cooling operation.

When the temperature in the heat storage tank is determined in step S1 and step S4, the suspension time may be set in advance in order to prevent hunting due to excessive opening and closing of the respective opening / closing devices. For example, in step S1 and step S4, when the set grace period T ₂ after the determination is made, the processing in the next step is performed.

  Here, the process shown in the flowchart of FIG. 4 is a process for securing the temperature in the heat storage tank, and is performed independently of other controls such as protection control. Therefore, when the operation of each switching device by protection control or the like intervenes between processing in each step, protection control may be prioritized. For example, when the refrigeration oil is not cooled and the discharge temperature of the compressor 11 rises and the protection control works, the first oil supply bypass opening / closing device 42 is “even when the processing of step S5 is performed. There is a case where discharge temperature suppression control may be performed in the closed state.

(During defrosting operation)
Next, processing at the time of defrosting operation will be described with reference to FIG. In step S11, the control device 50 determines whether it is time to start the defrosting operation. The control device 50 determines the timing to start the defrosting operation according to the time, the operation integration time of the compressor 11, or the operation state of the unit. For example, when the driving schedule is set in advance, the defrosting operation is started along the set schedule.

  If it is determined that it is time to start the defrosting operation (step S11; Yes), the process proceeds to step S12. On the other hand, when it is judged that it is not the timing which starts defrosting operation (Step S11; No), processing returns to Step S11 and repeats processing of Step S11 until it becomes timing which starts defrosting operation.

  In step S12, the control device 50 determines whether the temperature in the heat storage tank detected by the temperature sensor 34 is equal to or higher than the set temperature. If it is determined that the temperature in the heat storage tank is less than the set temperature (step S12; No), the process proceeds to step S13.

  In step S13, the control device 50 starts the defrosting operation, and the first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device so that the refrigerator oil in the heat storage tank 32 does not return to the refrigerator unit 10. Set each of 45 to the "closed" state. Further, the control device 50 sets the second refueling bypass opening / closing device 43 in the “open” state. Furthermore, in order to secure the temperature in the heat storage tank 32, the control device 50 turns on the auxiliary heater 33 to heat the refrigerator oil in the heat storage tank 32. When the auxiliary heater 33 is not provided, the control for the auxiliary heater 33 may not be performed.

  Further, at this time, in order to prevent the oil temperature in the refrigerator unit 10 from being lowered, the control device 50 puts the first oil supply bypass opening / closing device 42 in the “open” state. However, when the discharge temperature of the compressor 11 exceeds the specified value, the control device 50 cools the refrigerator oil with the oil cooler 41 with the first oil supply bypass opening / closing device 42 in the “closed” state.

  Next, in step S14, the control device 50 determines whether the temperature in the heat storage tank detected by the temperature sensor 34 is less than the set temperature. This is a process set as a condition for turning off the auxiliary heater 33 in order to suppress the power consumption which is increased by turning on the auxiliary heater 33 in step S13.

  When the temperature in the heat storage tank is equal to or higher than the set temperature (step S14; No), the control device 50 turns off the auxiliary heater 33 in step S15. On the other hand, when the temperature in the heat storage tank is less than the set temperature (step S14; Yes), the process returns to step S14, and the process of step S14 is repeated until the condition of step S14 is satisfied.

  The ON and OFF states of the auxiliary heater 33 are not limited to this example, and may be determined according to the installation environment or the operating state of the unit. For example, during the defrosting operation, the auxiliary heater 33 may be always on. Further, for example, when the second decompression device 35 can decompress according to the temperature in the heat storage tank 32, the auxiliary heater 33 may be always turned off.

  On the other hand, when it is determined in step S12 that the temperature in the heat storage tank is equal to or higher than the set temperature (step S12; Yes), the process proceeds to step S16. In step S16, the control device 50 starts the defrosting operation, and sets each of the first heat storage circuit opening / closing device 44 and the second heat storage circuit opening / closing device 45 in the “closed” state. Further, the control device 50 sets the second refueling bypass opening / closing device 43 in the “open” state.

[Modification of refrigeration system]
Next, a modification of the first embodiment will be described. FIG. 6 is a block diagram showing an example of the configuration of a refrigeration apparatus 1 according to a modification of the first embodiment. In addition, in the following description, about the part which is common in the freezing apparatus 1 shown in FIG. 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  As shown in FIG. 6, the refrigeration system 1 according to the modification connects the hot gas piping provided with the first hot gas switching device 16 in the refrigerator unit 10 to the downstream side of the first liquid switching device 15. Instead, it is connected to the upstream side of the second hot gas switchgear 24 of the cooler unit 20. Then, the bypass of the first pressure reducing device 22 in the cooler unit 20 is removed, and the first liquid switching device 15 in the refrigerator unit 10 is removed.

  In this case, the second liquid switching device 23 in the cooler unit 20 replaces the first liquid switching device 15 in the first embodiment. Therefore, the second liquid opening / closing device 23 operates in the same manner as the first liquid opening / closing device 15 in the cooling operation, the defrosting operation, the pump down operation, and the stop. Thereby, the refrigeration apparatus 1 according to the modification can be operated in the same manner as the refrigeration apparatus 1 according to the first embodiment.

  As described above, the refrigeration apparatus 1 according to the first embodiment compresses the refrigerant and discharges it together with the refrigerator oil. The oil separator 12 separates the refrigerant discharged from the compressor 11 and the refrigerator oil. And a refrigerator unit 10 having a heat source side heat exchanger 13 for exchanging heat between the refrigerant separated by the oil separator 12 and the heat source medium, and the refrigerator unit 10 and the first main pipe 2 are connected, A cooler unit 20 having a use side heat exchanger 21 for performing heat exchange between a refrigerant flowing in from the refrigerator unit 10 via the first main pipe 2 and a use medium, a cooler unit 20 and a refrigerator unit 10 And the second main pipe 3, and are connected to the refrigerator unit 10 through the first oil pipe 4 and the second oil pipe 5, and flow from the refrigerator unit 10 through the first oil pipe 4 , Separated by oil separator 12 The refrigerating machine oil and a heat storage unit 30 having the heat storage tank 32 for storing the heat storage material.

  Thus, the heat storage unit 30 is connected to the refrigerator unit 10 by the second main pipe 3, the first oil pipe 4 and the second oil pipe 5, and is connected to the cooler unit 20 by the second main pipe 3. Ru. Therefore, the number of pipes connected to the heat storage unit 30 can be reduced as compared to the conventional case, and the workability can be improved.

  Further, in this refrigeration system 1, since refrigeration oil is used as the thermal storage medium, even if the thermal storage medium is mixed in the refrigeration cycle due to some abnormality, it becomes unnecessary to totally recover and recharge the refrigerant and the thermal storage medium, and the quality of the system It is possible to suppress the decrease.

  As mentioned above, although Embodiment 1 and the modification of this invention were demonstrated, this invention is not limited to Embodiment 1 and the modification of this invention mentioned above, Within the range which does not deviate from the summary of this invention Various modifications and applications are possible. For example, in the first embodiment and the modification, the type of refrigerant is not particularly specified, but a high-pressure refrigerant such as R410A tends to have a high temperature of the refrigerator oil, so using R410A as a refrigerant makes A heat storage effect can be obtained. However, even in the case of a refrigerant which has a high pressure and a low discharge temperature, such as R404A, which is lower than R410A, a sufficient effect can be obtained by devising an oil cooler 41, for example.

  Reference Signs List 1 refrigeration system, 2 first main pipe, 3 second main pipe, 10 refrigerator unit, 11 compressor, 12 oil separator, 13 heat source side heat exchanger, 14 accumulator, 15 first liquid switch, 16 first 1 hot gas switchgear, 20 cooler unit, 21 use side heat exchanger, 22 first pressure reducer, 23 second liquid switchgear, 24 second hot gas switchgear, 30 heat storage unit, 31 refrigerant flow Path switching device, 32 heat storage tank, 32a heat storage side heat exchanger, 33 auxiliary heater, 34 temperature sensor, 35 second pressure reducing device, 40 oil feeding circuit, 41 oil cooler, 42 first oil bypass valve, 43 first 2 refueling bypass switchgear, 44 first heat storage circuit switchgear, 45 second heat storage circuit switchgear, 50 controller.

Claims (6)

A compressor that compresses a refrigerant and discharges it with a refrigerator oil, an oil separator that separates the refrigerant discharged from the compressor and the refrigerator oil, and a refrigerant and a heat source medium that are separated by the oil separator A refrigerator unit having a heat source side heat exchanger for performing heat exchange between the units;
A cooler unit having a use side heat exchanger connected to the refrigerator unit by a first main pipe and performing heat exchange between a refrigerant flowing from the refrigerator unit via the first main pipe and a use medium When,
The refrigerator unit and the refrigerator unit are connected by a second main pipe, and are connected to the refrigerator unit by first and second oil pipes, and the refrigerator unit is connected via the first oil pipe. And a heat storage unit having a heat storage tank for storing the refrigerator oil separated by the oil separator as a heat storage material, which flows from the The heat storage unit is
During the cooling operation for cooling the utilization medium,
The refrigerant flowing from the cooler unit is allowed to flow out to the refrigerator unit via the second main pipe,
The refrigeration apparatus according to claim 1, wherein the refrigeration oil that flows in via the first oil pipe is stored in the heat storage tank. The heat storage unit is
At the time of defrosting operation which removes frost formation of the use side heat exchanger,
The refrigeration apparatus according to claim 1 or 2, wherein heat exchange is performed between the refrigerant flowing from the cooler unit via the second main pipe and the refrigeration oil stored in the heat storage tank. The refrigerator unit is
It further comprises a bypass opening / closing device provided between the first oil pipe and the second oil pipe, for controlling the flow of the refrigeration oil separated by the oil separator into the heat storage tank,
The heat storage unit is
A first heat storage circuit opening / closing device provided in the first oil pipe and controlling inflow of the refrigerator oil into the heat storage tank;
The refrigeration system according to any one of claims 1 to 3, further comprising: a second heat storage circuit opening / closing device provided in the second oil pipe and controlling an outflow of the refrigerator oil from the heat storage tank. During the cooling operation for cooling the utilization medium,
The bypass switchgear is closed.
The refrigerating apparatus according to claim 4, wherein the first and second heat storage circuit switching devices are opened. At the time of defrosting operation which removes frost formation of the use side heat exchanger,
The bypass switchgear is open;
The refrigeration system according to claim 4 or 5, wherein the first and second heat storage circuit switching devices are closed.

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