JP2011038711A - Turbo refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbo refrigerator performing stable operation with high efficiency by circulating a necessary and sufficient liquid refrigerant, while properly preventing blow-by of refrigerant stem from a capacitor to an intermediate cooler or from the intermediate cooler to an evaporator, even when partial loaded condition or the cooling-water temperature is decreased, as during intermediate periods. <P>SOLUTION: The turbo refrigerator includes a compressor 1, the evaporator 2, the capacitor 3 and the intermediate cooler 4 and further, includes a high-pressure side motor-operated valve 11, arranged in piping for delivering a refrigerant liquid condensed by the capacitor 3 to the intermediate cooler 4; a low-pressure side motor-operated valve 12, arranged in piping for delivering the refrigerant liquid cooled by depressurization and boiling of the refrigerant in the intermediate cooler 4 to the evaporator 2; and a control part 20 controlling the opening of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12. The control part 20 controls the opening of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12, based on a physical quantity equivalent to a pressure difference between the high-pressure side and the low-pressure side of a refrigeration cycle and a physical quantity equivalent to a refrigerant circulation amount of the refrigeration cycle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a refrigerator, and more particularly to a multistage compression turbo refrigerator.

  Conventionally, a high-pressure motor-operated valve is provided in a pipe that sends the refrigerant liquid condensed in the condenser to the intermediate cooler, and a pipe that guides the refrigerant vapor boiled in the intermediate cooler to the intermediate pressure part of the turbo compressor is provided. A turbo chiller that sends a cooled refrigerant liquid from an intermediate cooler to an evaporator has been proposed (for example, Patent Document 1).

JP-A-11-344265

  In such a turbo refrigerator, the ease of flow of the refrigerant from the condenser to the evaporator through the intermediate cooler varies depending on the pressure difference between the outlet side and the inlet side of the compressor. Therefore, from the viewpoint of ease of refrigerant flow, it is considered that the opening degrees of the high-pressure side motor-operated valve and the low-pressure side motor-operated valve may be adjusted based on the pressure difference.

  By the way, in recent years, not only the operation efficiency and stability under the so-called rated conditions, but also the demand for operation efficiency and stability when the partial load condition and the cooling water temperature are lowered, such as an intermediate period, is increasing. In this case, a phenomenon not in the rated condition may occur.

  For this reason, only the adjustment based on the pressure difference cannot appropriately control the opening degrees of the high-pressure side motor-operated valve and the low-pressure side motor-operated valve, and it is impossible to maintain a good operating state of the turbo refrigerator. It was discovered.

  For example, if the opening of the high-pressure side motor-operated valve and the low-pressure side motor-operated valve is increased when the partial load condition or cooling water temperature is reduced, such as during an intermediate period, not only the refrigerant liquid but also the refrigerant A phenomenon in which steam is sent (so-called refrigerant vapor blow-through) may occur. In this case, this amount of refrigerant does not work and compresses useless refrigerant, resulting in low operating efficiency.

  However, heretofore, there is no turbo chiller considered in terms of controlling the opening degree of the high pressure side motor operated valve and the low pressure side motor operated valve from such a viewpoint.

  Accordingly, an object of the present invention is to suitably prevent the refrigerant vapor from being blown from the condenser to the intermediate cooler or from the intermediate cooler to the evaporator even when the partial load condition or the cooling water temperature is lowered, such as in an intermediate period. However, it is to provide a turbo chiller capable of circulating a necessary and sufficient liquid refrigerant and performing stable and highly efficient operation.

  In order to achieve the above object, the present invention comprises a refrigeration cycle configured by sequentially connecting a compressor, an evaporator, a condenser, and an intercooler, and the refrigerant liquid condensed by the condenser is supplied to the intercooler. A high-pressure side motor-operated valve provided in the pipe to be sent, a low-pressure side motor-operated valve provided in a pipe for sending the refrigerant liquid cooled by boiling the refrigerant in the intermediate cooler to the evaporator, the high-pressure side motor-operated valve and the low-pressure side A control unit that controls the opening degree of the motorized valve, and the control unit is based on a physical quantity corresponding to the pressure difference between the high-pressure side and the low-pressure side of the refrigeration cycle and a physical quantity corresponding to the refrigerant circulation amount of the refrigeration cycle, The opening degree of the high-pressure side electric valve and the low-pressure side electric valve is controlled.

In order to achieve the above object, the present invention includes a refrigeration cycle in which a compressor, an evaporator, a condenser, and an intercooler are sequentially connected, and the refrigerant liquid condensed by the condenser is intercooled. A high-pressure side motor-operated valve provided in a pipe to be sent to the evaporator, a low-pressure side motor-operated valve provided in a pipe for sending refrigerant liquid cooled by boiling the refrigerant in the intermediate cooler to the evaporator, the high-pressure side motor-operated valve, And a control unit that controls the opening of the low-pressure side electric valve, and the control unit controls the opening of the high-pressure side electric valve and the low-pressure side electric valve in synchronization.
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  According to the turbo chiller of the present invention, it is preferable to blow through the refrigerant vapor from the condenser to the intermediate cooler or from the intermediate cooler to the evaporator even when the partial load condition or the cooling water temperature is lowered, such as in the intermediate period. Therefore, it is possible to circulate necessary and sufficient liquid refrigerant and perform stable and highly efficient operation.

The systematic diagram which shows one Example of the turbo refrigerator of this invention. The systematic diagram which shows the other Example of the turbo refrigerator of this invention.

  Hereinafter, an embodiment of a turbo refrigerator according to the present invention will be described.

  The turbo refrigerator according to this embodiment includes a refrigeration cycle configured by sequentially connecting a compressor 1, an evaporator 2, a condenser 3, and an intercooler 4, and intercools the refrigerant liquid condensed by the condenser 3. A high-pressure motor-operated valve 11 provided in a pipe to be sent to the evaporator 4, a low-pressure motor-operated valve 12 provided in a pipe to which the refrigerant liquid cooled by boiling the refrigerant in the intermediate cooler 4 is sent to the evaporator 2; A control unit 20 that controls the opening degree of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12, and the control unit 20 has a physical quantity corresponding to a pressure difference between the high-pressure side and the low-pressure side of the refrigeration cycle, and The opening degree of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 is controlled based on a physical quantity corresponding to the refrigerant circulation amount.

  According to the above configuration, by controlling the opening degree of the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 based on both the physical quantity corresponding to the pressure difference and the physical quantity corresponding to the refrigerant circulation amount, Even when the partial load condition or the cooling water temperature is lowered, there is no blowing of refrigerant vapor from the condenser 3 to the intermediate cooler 4 or from the intermediate cooler 4 to the evaporator 2, and the necessary and sufficient liquid refrigerant is circulated. Stable and efficient operation can be performed.

  Further, the control unit 20 controls the opening degrees of the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 in synchronization. Thus, by controlling the opening degree of the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 in synchronization, the pressure balance between the high pressure side and the low pressure side is not unstable, and the operation is stable and highly efficient. It can be performed.

  The physical quantity corresponding to the pressure difference between the high pressure side and the low pressure side of the refrigeration cycle is determined based on the temperature difference between the outlet temperature of the cold water flowing through the evaporator 2 and the inlet temperature of the cooling water flowing through the condenser 3. Is done.

  The physical quantity corresponding to the refrigerant circulation amount of the refrigeration cycle is determined based on the temperature difference between the inlet temperature and the outlet temperature of the cold water flowing through the evaporator 2. Here, the cold water outlet temperature may be a cold water outlet temperature detected by a temperature sensor or the like, or may be a target temperature of the cold water outlet temperature.

  The control unit 20 is configured to control the high-pressure side based on a physical amount corresponding to a pressure difference between the high-pressure side and the low-pressure side of the refrigeration cycle and a predetermined opening corresponding to a physical amount corresponding to the refrigerant circulation amount of the refrigeration cycle. The motorized valve 11 and the low pressure side motorized valve 12 are controlled.

  The turbo chiller is provided with a fixed throttle channel in parallel with the high-pressure side motor operated valve 11 in the pipe for sending the refrigerant liquid from the condenser 3 to the intermediate cooler 4, and from the intermediate cooler 4 to the evaporator 2. A fixed throttle passage is provided in parallel with the low-pressure motor-operated valve 12 in the pipe for sending the refrigerant liquid to the pipe.

  Hereinafter, Example 1 will be described with reference to FIG.

  FIG. 1 shows a configuration of a turbo refrigerator in the present invention. The turbo refrigerator constitutes a refrigeration cycle by connecting a compressor 1, an evaporator 2, a condenser 3, and an intercooler 4 by piping. The compressor 1 is configured in multiple stages and includes a plurality of stages of impellers. The compressor 1 is a compressor whose rotational speed is controlled by an inverter.

  The refrigerant vapor compressed by the compressor 1 is sent to the condenser 3 and is cooled by the cooling water flowing in the condenser 3 to be condensed and liquefied. The liquefied refrigerant liquid is depressurized through the high-pressure side motor operated valve 11 provided in the middle of the pipe connecting the condenser 3 and the intermediate cooler 4 and sent to the intermediate cooler 4. A part of the refrigerant liquid sent to the intercooler 4 is self-evaporated due to decompression, and the temperature of the remaining refrigerant liquid is lowered. The refrigerant liquid whose temperature has been reduced is reduced in pressure through the low-pressure motor-operated valve 12 provided in the middle of the pipe connecting the intercooler 4 and the evaporator 2, and is sent to the evaporator 2. The refrigerant liquid sent to the evaporator 2 is heated and evaporated by the cold water flowing in the evaporator 2 and is sent to the compressor 1 as refrigerant vapor. The cold water that has heated the refrigerant liquid is supplied to the outside as cold water having a lowered temperature. The refrigerant vapor sent to the compressor 1 is compressed by a multistage impeller and becomes high-temperature and high-pressure refrigerant vapor.

  The refrigerant vapor self-evaporated by the intermediate cooler 4 passes through the motor-operated valve 13 provided in the middle of the pipe connecting the intermediate cooler 4 and the compressor 1, and the inlets of the second and subsequent impellers of the compressor 1. The refrigerant vapor from the evaporator 2 compressed by the first stage impeller is joined to the second stage and subsequent impellers to become high-temperature and high-pressure refrigerant vapor, which is sent to the condenser 3. As described above, the refrigeration cycle is completed.

  The chilled water piping of the evaporator 2 is provided with a temperature sensor 21 for measuring the chilled water outlet temperature and a temperature sensor 22 for measuring the chilled water inlet temperature, and the cooling water piping of the condenser 3 is a temperature for measuring the cooling water inlet temperature. A sensor 23 is provided. A control unit 20 is provided for inputting the signals of the temperature sensors 21, 22, and 23 and controlling the opening degrees of the high-pressure side electric valve 11 and the low-pressure side electric valve 12 based on these signals. . The control unit 20 also opens and closes the motor-operated valve 13 provided in the middle of the pipe connecting the intercooler 4 and the compressor 1 and controls the rotational speed of the compressor 1 based on the signals of the temperature sensors 21, 22 and 23. Do.

  The control unit 20 receives and holds a target value of the cold water outlet temperature from the outside, and the difference between the cold water inlet temperature obtained from the signal of the temperature sensor 22 that measures the cold water inlet temperature and the target value of the cold water outlet temperature. From the difference between the cooling water inlet temperature and the cooling water outlet temperature obtained from the signals of the temperature sensor 23 for measuring the required refrigeration capacity of the turbo refrigerator and the temperature sensor 23 for measuring the cooling water inlet temperature and the temperature sensor 21 for measuring the cooling water outlet temperature. Calculate the pumping temperature difference of the machine.

  The control unit 20 also includes the high-pressure motor-operated valve 11 and the intermediate cooler 4 provided in a pipe connecting the condenser 3 and the intermediate cooler 4 according to the required refrigeration capacity and the pumping temperature difference value. A data map (see Table 1) for changing the opening degree of each of the low-pressure side motor operated valves 12 provided in the pipe connecting the evaporators 2 in a stepwise manner is held, and the high pressure side motor operated valve 11 according to this data map. And the opening degree of the said low voltage | pressure side motor operated valve 12 is controlled. The flow rate in Table 1 corresponds to the freezing capacity, and the pressure difference corresponds to the pumping temperature difference.

  Table 1 schematically shows a data map, and the pressure difference value and the flow rate value that divide each region are not fixed to a constant value, and may be different for each adjacent region. It may be a function of pressure difference or flow rate.

  The data map shown in Table 1 shows that, among the areas where the compressor 1 is inverter-controlled, the area where the required refrigeration capacity is large and the pumping temperature difference is small has a large opening, the necessary refrigeration capacity is small and the pumping temperature difference is large. The opening is set to be small.

  According to this data map, the required refrigeration capacity is large in the inverter controlled region, that is, the refrigerant circulation amount is large and the pumping temperature difference is small, that is, the pressure difference between the condenser 3 and the intercooler 4 and the intercooler 4. In the region where the pressure difference between the gas generator and the evaporator 2 is small (specifically, the region where the flow rate is 4 and the pressure difference is small), the opening degree of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 is greatly controlled. While ensuring the amount of refrigerant circulation, it is possible to prevent the refrigerant vapor from being blown out and prevent the performance from deteriorating.

  On the other hand, the required refrigeration capacity is small, that is, the refrigerant circulation amount is small, and the pumping temperature difference is large, that is, the pressure difference between the condenser 3 and the intermediate cooler 4 and the pressure difference between the intermediate cooler 4 and the evaporator 2 are In a large region (specifically, a region where the flow rate is 3 and the pressure difference is large), the opening degree of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 is controlled to be small, thereby preventing the refrigerant vapor from blowing through and preventing performance deterioration. In addition, the cycle can be established by securing the necessary amount of refrigerant circulation.

  And in the region where the refrigerant circulation amount is small and the pressure difference is small (specifically, the region where the flow rate is 3 and the pressure difference is small), such as when the partial load condition or the cooling water temperature is lowered, such as an intermediate period, The opening degree of the side electric valve 11 and the low pressure side electric valve 12 is larger than the opening degree in a region where the refrigerant circulation amount is small and the pressure difference is large (specifically, a region where the flow rate is 3 and the pressure difference is large), It is controlled to be smaller than the opening degree in the region where the refrigerant circulation amount is large and the pressure difference is small (specifically, the region where the flow rate is 4 and the pressure difference is small).

  Further, the control unit 20 controls the rotation speed of the compressor 1 based on the difference between the target value of the chilled water outlet temperature and the chilled water inlet temperature obtained from the signal of the temperature sensor 22 for measuring the chilled water inlet temperature. Adjust the amount of refrigerant. Further, the control unit 20 performs control so that the motor-operated valve 13 provided in the middle of the pipe connecting the intermediate cooler 4 and the compressor 1 is closed when the required refrigeration capacity is extremely small.

  Further, as shown in Table 1, in the region where the refrigerating capacity (refrigerant flow rate) is small, in addition to inverter control, control for restricting the inlet guide vane at the compressor inlet is performed. In this case, in order to prevent the mist from the intermediate cooler 4, the opening degree of the low pressure side electric valve 12 is largely controlled, and the opening degree of the high pressure side electric valve 11 is also increased.

  Moreover, the opening degree of the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 is controlled in synchronization. In addition, when controlling the opening degree of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 in synchronization, in addition to changing the opening degree of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 simultaneously, The high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 may be controlled at intervals. In other words, when the opening degree of one of the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 is changed, the other opening degree may be changed in conjunction therewith.

  In the present embodiment configured as described above, refrigerant vapor is blown from the condenser 3 to the intermediate cooler 4 or from the intermediate cooler 4 to the evaporator 2 even when the partial load condition or the cooling water temperature is lowered. No mist up from the intercooler 4 to the compressor 1 occurs, and a necessary and sufficient liquid refrigerant can be circulated to perform a stable and highly efficient operation.

  Further, in this embodiment, the rotational speed of the compressor 1 is controlled according to the difference between the target value of the cold water outlet temperature and the cold water outlet temperature obtained from the signal of the temperature sensor 21 that measures the cold water outlet temperature. However, by providing an inlet guide vane at the inlet of each stage impeller of the compressor 1 and changing the angle of the inlet guide vane, the flow of the refrigerant vapor is adjusted and the refrigerant flow rate and the compression ratio of the compressor 1 are adjusted. May be controlled. In the case of such a configuration, an inverter control device for controlling the rotation speed of the motor that drives the compressor 1 becomes unnecessary, and there is an advantage that the cost can be reduced.

  Next, Example 2 will be described with reference to FIG.

  FIG. 2 shows a configuration of a turbo refrigerator in the present invention. The difference from the embodiment of FIG. 1 is that a pipe having a fixed throttle 14 is provided in parallel with the high-pressure side motor operated valve 11 provided in the pipe connecting the condenser 3 and the intermediate cooler 4, and the intermediate cooler 4 and the evaporator 2 are connected. This is a point in which a pipe having a fixed throttle 15 is provided in parallel with the low-pressure side electric valve 12 provided in the pipe to be connected. Other configurations are the same as those of the embodiment of FIG.

  In the present embodiment configured as described above, since the fixed throttles 14 and 15 are provided in parallel with the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12, the sizes of the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 are provided. The cost can be measured by reducing In addition, since the fixed throttles 14 and 15 can always circulate the refrigerant, even if the high-pressure side motor-operated valve 11 and the low-pressure side motor-operated valve 12 are out of order, the fixed throttles 14 and 15 operate the turbo chiller although the refrigeration capacity is small. be able to.

  In addition, the turbo refrigerator which concerns on this invention is not limited to the structure of the said embodiment, A various change is possible within the range which does not deviate from the meaning of invention.

  For example, the cold water outlet temperature detected by a temperature sensor may be used as the cold water outlet temperature, or the target temperature of the cold water outlet temperature may be used. Moreover, when cooling water is cooled using a cooling tower, the outside air temperature may be used instead of the cooling water inlet temperature.

  Further, the physical quantity corresponding to the pressure difference between the high pressure side and the low pressure side is not limited to the one that indirectly detects the pressure difference using the temperature sensor, and may be one that is directly detected using the pressure sensor. Good.

  In addition, the present invention, from the viewpoint of controlling the opening degree of the high pressure side motor operated valve 11 and the low pressure side motor operated valve 12 in synchronism, “high pressure based on a physical quantity corresponding to the pressure difference and a physical quantity corresponding to the refrigerant circulation amount”. “Controlling the opening degree of the side motor-operated valve 11 and the low-pressure side motor-operated valve 12” is not an essential requirement. For example, a liquid level sensor is provided in the intermediate cooler 4, the liquid level sensor detects the liquid level height of the intermediate cooler 4, and the high-pressure side electric valve 11 and the low pressure are detected according to the liquid level height of the intermediate cooler 4. By controlling the opening degree of the side motor operated valve 12 in synchronism, the refrigerant vapor may be prevented from being blown through.

  According to the turbo chiller according to the present embodiment, the refrigerant vapor is blown from the condenser to the intermediate cooler or from the intermediate cooler to the evaporator even when the partial load condition or the cooling water temperature is lowered, such as in the intermediate period. In this way, it is possible to circulate necessary and sufficient liquid refrigerant and perform stable and highly efficient operation.

  In addition, a temperature sensor that measures the inlet temperature and outlet temperature of the chilled water that flows to the evaporator and a temperature sensor that measures the inlet temperature of the cooling water that flows to the condenser are provided. Based on these temperatures, intermediate cooling from the condenser is provided. As a configuration provided with a control device for controlling the opening degree of the high-pressure side motor-operated valve provided in the pipe for sending the refrigerant liquid to the evaporator and the opening degree of the low-pressure side motor-operated valve provided in the pipe for sending the refrigerant liquid from the intercooler to the evaporator Therefore, even when the partial load condition or cooling water temperature decreases, there is no blowing of refrigerant vapor from the condenser to the intercooler or from the intercooler to the evaporator, and mist up from the intercooler to the compressor Therefore, it is possible to perform a stable and highly efficient operation by circulating a necessary and sufficient liquid refrigerant.

  Further, according to the turbo chiller according to the present embodiment, the required refrigeration capacity and the pumping temperature difference are calculated from the target value of the chilled water outlet temperature and the measured values of the chilled water inlet temperature, the chilled water outlet temperature, and the cooling water inlet temperature, Based on the calculation result, the opening degree of the high-pressure side motor-operated valve provided in the pipe that sends the refrigerant liquid from the condenser to the intermediate cooler, and the low-pressure side motor-operated valve provided in the pipe that sends the refrigerant liquid from the intermediate cooler to the evaporator Is controlled according to a data map that changes in stages, so that refrigerant vapor from the condenser to the intercooler, or from the intercooler to the evaporator, even when the partial load condition or cooling water temperature falls There is no blow-through, no mist up from the intercooler to the compressor occurs, and a necessary and sufficient liquid refrigerant is circulated to enable stable and efficient operation.

  Further, according to the turbo chiller according to the present embodiment, the fixed throttle passage is provided in parallel with the high-pressure side motor operated valve provided in the pipe for sending the refrigerant liquid from the condenser to the intermediate cooler, and the intermediate cooler is changed to the evaporator. Since the fixed throttle channel is provided in parallel with the low-pressure side motorized valve provided in the pipe for sending the refrigerant liquid, the size of each motorized valve can be reduced and the cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Evaporator 3 Condenser 4 Intermediate cooler 11 High-pressure side motor-operated valve 12 Low-pressure side motor-operated valve 13 Motor-operated valves 14 and 15 Fixed throttle 20 Controllers 21, 22, and 23 Temperature sensor

Claims (7)

It has a refrigeration cycle consisting of a compressor, an evaporator, a condenser, and an intercooler connected in sequence,
A high-pressure side motor-operated valve provided in a pipe for sending the refrigerant liquid condensed in the condenser to the intercooler;
A low-pressure side motor-operated valve provided in a pipe for sending the refrigerant liquid cooled by boiling the refrigerant under reduced pressure in the intermediate cooler to the evaporator;
A controller for controlling the opening of the high-pressure side motorized valve and the low-pressure side motorized valve,
The controller controls the opening degrees of the high-pressure side motor-operated valve and the low-pressure side motor-operated valve based on a physical quantity corresponding to a pressure difference between the high-pressure side and the low-pressure side of the refrigeration cycle and a physical quantity equivalent to a refrigerant circulation amount of the refrigeration cycle. A turbo refrigerator characterized by controlling.   The turbo chiller according to claim 1, wherein the control unit controls the opening degrees of the high-pressure side electric valve and the low-pressure side electric valve in synchronization. It has a refrigeration cycle consisting of a compressor, an evaporator, a condenser, and an intercooler connected in sequence,
A high-pressure side motor-operated valve provided in a pipe for sending the refrigerant liquid condensed in the condenser to the intercooler;
A low-pressure side motor-operated valve provided in a pipe for sending the refrigerant liquid cooled by boiling the refrigerant under reduced pressure in the intermediate cooler to the evaporator;
A control unit for controlling the opening of the high-pressure side motorized valve and the low-pressure side motorized valve,
The said control part synchronizes and controls the opening degree of the said high voltage | pressure side motor operated valve and a low voltage | pressure side motor operated valve, The turbo refrigerator characterized by the above-mentioned.   The physical quantity corresponding to the pressure difference between the high pressure side and the low pressure side of the refrigeration cycle is determined based on the temperature difference between the outlet temperature of the cold water flowing through the evaporator and the inlet temperature of the cooling water flowing through the condenser. The turbo refrigerator as described in any one of Claims 1-3 characterized by the above-mentioned.   The physical quantity corresponding to the refrigerant circulation amount of the refrigeration cycle is determined based on a temperature difference between an inlet temperature and an outlet temperature of cold water flowing through the evaporator. The turbo refrigerator as described in.   The controller controls the high-pressure side electric motor based on a physical quantity corresponding to a pressure difference between the high-pressure side and the low-pressure side of the refrigeration cycle and an opening determined in advance corresponding to a physical quantity corresponding to the refrigerant circulation amount of the refrigeration cycle. The turbo chiller according to any one of claims 1 to 5, wherein the valve and the low-pressure side electric valve are controlled. A pipe for sending the refrigerant liquid from the condenser to the intermediate cooler is provided with a fixed throttle channel in parallel with the high-pressure side motor operated valve,
The turbo refrigeration according to any one of claims 1 to 6, wherein a fixed throttle passage is provided in parallel with the low-pressure side motor operated valve in a pipe for sending the refrigerant liquid from the intermediate cooler to the evaporator. Machine.

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