CONTROL DEVICE FOR REFRIGERATOR SYSTEM, REFRIGERATOR SYSTEM, CONTROL METHOD FOR REFRIGERATOR SYSTEM, AND CONTROL PROGRAM FOR REFRIGERATOR SYSTEM

Abstract

There is provided a chiller control device (50) of a chiller system (1) that is provided with a centrifugal chiller (11) provided with a compressor (60) rotated by a motor (72), an operation panel (20) which is provided in the centrifugal chiller (11), operates the centrifugal chiller (11), and displays a state of the centrifugal chiller (11), and a starting panel (20) which supplies power to the motor (72) and starts the motor (72). The starting panel (10) begins supplying power to the motor (72) of the compressor (60) in response to a start command from the centrifugal chiller (11) to start the motor (72), and outputs a start answer and a start completion signal to the centrifugal chiller (11), and an abnormal state is output to the operation panel (20) if the start answer and/or the start completion signal continue to be output after the centrifugal chiller (11) has stopped.

Description

TECHNICAL FIELD

The present invention relates to a control device for a chiller system, the chiller system, a control method for the chiller system, and a control program for the chiller system.

BACKGROUND ART

There are disclosed various methods for monitoring a failure of a chiller such as a centrifugal chiller.

PTL 1 discloses a method in which an operation state of a centrifugal chiller is remotely monitored, and if an abnormality is detected, the centrifugal chiller stops. PTL 2 discloses a method in which if an abnormality is detected, a maintenance service person is notified of the abnormality.

CITATION LIST

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2002-90011

[PTL 2] Japanese Unexamined Patent Application Publi cation No. 2003-223522

SUMMARY OF INVENTION

Technical Problem

If a motor starts, a compressor provided in the chiller begins rotating. If the capacity of the motor is large (for example, 1,500 KW), it is necessary to prepare a device called as a starting panel dedicated to starting the motor. A high current is required to flow at a high voltage to start the motor, and the starting panel is a device by which power corresponding to the requirement is supplied to the motor.

Generally, a chiller and a starting panel are used which operate using the same control logic, but a starting panel may be prepared which operates using a control logic different from a control logic of a chiller. In this case, because the control logics are different, even though the chiller outputs a stop request command, there is a possibility that the starting panel does not receive the stop request command. If the starting panel has not received the stop request command, because it is not possible to stop supplying power to the compressor, the compressor cannot stop, thereby leading to a failure of the chiller, which is a problem.

In the inventions disclosed in PTL 1 and PTL 2, the problem has not been examined, and means for solving the problem has not been disclosed.

The present invention has been made in light of the problem, and an object of the present invention is to provide a control device for a chiller system which is provided with a starting panel operating using a control logic different from a control logic of a chiller, and is capable of properly stopping a compressor, the chiller system, a control method for the chiller system, and a control program for the chiller system.

Solution to Problem

In the present invention, in order to solve the problem, a control device for a chiller system, the chiller system, a control method for the chiller system, and a control program for the chiller system adopt the following means.

According to a first aspect of the present invention, there is provided a control device for a chiller system that is provided with a chiller provided with a compressor rotated by a motor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor, in which the starting panel begins supplying power to the motor of the compressor in response to a start command from the chiller to start the motor, and outputs a motor start signal and a start completion signal to the chiller, and in which if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an abnormal state is output to the operation panel.

According to the aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an abnormal state is output to the operation panel of the chiller. In the aspect, it is possible to notify an outside system that the compressor continues to rotate after the chiller has stopped, and it is possible to notify an operator of the abnormality. Because the operator having received the notification stops the compressor, it is possible to properly stop the compressor, and to prevent a failure of the chiller.

According to a second aspect of the present invention, there is provided a control device for a chiller system that is provided with a chiller provided with a compressor rotated by a motor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor, in which the starting panel begins supplying power to the motor of the compressor in response to a start command from the chiller to start the motor, and outputs a motor start signal and a start completion signal to the chiller, and in which if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an emergency stop command is output from the operation panel to the starting panel.

According to the aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an emergency stop command is output from the operation panel of the chiller to the starting panel. Therefore, according to the aspect, even though the compressor continues to rotate after the chiller has stopped, the starting panel is capable of receiving the emergency stop command, and making an emergency stop. As a result, it is possible to properly bring the compressor into an emergency stop without an operation of the operator being intervened, and to prevent a failure of the chiller.

In the first aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an emergency stop command may be output from the operation panel to the starting panel.

According to the aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an abnormal state is output to the operation panel, and an emergency stop command is output from the operation panel to the starting panel. Therefore, it is possible to properly bring the compressor into an emergency stop while notifying the operator of the abnormality.

In the second aspect, the emergency stop command may be a maintained signal.

If the emergency stop command is given as a pulse signal, and a stop timing is missed due to a failure, a stop cannot be made. In the aspect, because the emergency stop command is given as a maintained signal, the starting panel is more likely to receive the signal, and is capable of more properly making a stop.

In the first or second aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, a chilled water pump provided in an evaporator connected to the compressor may continue to operate, and a cooling water pump provided in a condenser may continue to operate.

According to the aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, the chilled water pump provided in the evaporator continues to operate, and the cooling water pump provided in the condenser continues to operate. Therefore, it is possible to protect a heat exchanger of the evaporator from freezing without producing chilled water.

In the first aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an oil pump, which is provided in the compressor to supply a lubricant, may continue to operate.

According to the aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, the oil pump of the compressor continues to operate. Therefore, it is possible to restrict the occurrence of lubricant deficiency in the compressor, and to protect the compressor.

In the first aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, a refrigerant control valve of the compressor may be controlled such that a chilled water outlet temperature of the chiller becomes equal to a chilled water inlet temperature of the chiller.

According to the aspect, if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, the refrigerant control valve of the compressor is controlled such that the chilled water outlet temperature of the chiller becomes equal to the chilled water inlet temperature of the chiller. Therefore, it is possible to prevent cooling refrigerant deficiency in the motor of the compressor by continuously controlling the refrigerant control valve not to produce the chilled water while circulating the refrigerant to the motor of the compressor.

According to a third aspect of the present invention, there is provided a chiller system including the control device for a chiller system.

According to a fourth aspect of the present invention, there is provided a control method for a chiller system that is provided with a chiller provided with a compressor rotated by a motor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor, the method including a step of beginning supplying power to the motor of the compressor from the starting panel in response to a start command from the chiller to start the motor, and of outputting a motor start signal and a start completion signal to the chiller from the starting panel; and a step of outputting an abnormal state to the operation panel if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped.

According to a fifth aspect of the present invention, there is provided a control program for a chiller system that is provided with a chiller provided with a compressor rotated by a motor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor, the program including a step of beginning supplying power to the motor of the compressor from the starting panel in response to a start command from the chiller to start the motor, and of outputting a motor start signal and a start completion signal to the chiller from the starting panel; and a step of outputting an abnormal state to the operation panel if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped.

Advantageous Effects of Invention

According to the present invention, because an operation state of the compressor after the chiller has stopped is monitored, the compressor is prevented from being subject to a damage induced when a stop is not normally made. Because it is possible to protect the chiller, it is possible to perform a stable operation.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram illustrating a chiller system of a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a chiller of the first embodiment of the present invention.

FIG. 3 is a time chart illustrating signals and operations of an operation panel and a starting panel in a normal state of operation as a reference example of the present invention.

FIG. 4 is a time chart illustrating signals and operations of the operation panel and the starting panel in an abnormal state of operation as a reference example of the present invention.

FIG. 5 is a flowchart illustrating control of a failure state determination unit of the first embodiment of the present invention.

FIG. 6 is a time chart illustrating signals and operations of the operation panel and the starting panel of the first embodiment of the present invention.

FIG. 7 is a flowchart illustrating control of the failure state determination unit of a second embodiment of the present invention.

FIG. 8 is a time chart illustrating an operation/stop command and an emergency stop command of the second embodiment of the present invention, and pulse signals as a reference example.

FIG. 9 is a time chart illustrating signals and operations of the operation panel and the starting panel of the second embodiment of the present invention.

FIG. 10 is a flowchart illustrating control of the failure state determination unit of a third embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinbelow, a control device for a chiller system, the chiller system, a control method for the chiller system, and a control program for the chiller system according to one embodiment of the present invention will be described with reference to the drawings.

First Embodiment

Hereinbelow, a first embodiment of the present invention will be described with reference to FIGS. 1 to 6.

FIG. 1 illustrates a schematic configuration of the control device for the chiller system, the chiller system, the control method for the chiller system, and the control program for the chiller system according to the embodiment.

As illustrated in FIG. 1, a chiller system 1 is provided with a centrifugal chiller (chiller) 11, a starting panel 10, and a chiller control device 50 as main configuration members.

The centrifugal chiller 11 is provided with an operation panel 20, and a compressor 60 rotated by a motor 72.

FIG. 2 illustrates a schematic configuration of the chiller of the embodiment.

As illustrated in FIG. 2, the centrifugal chiller 11 gives heat to or takes heat away from chilled water supplied to an external load 86 such as an air conditioner or a fan coil. The centrifugal chiller 11 is provided with the compressor 60 that compresses a refrigerant; a condenser 62 that condenses the high-temperature and high-pressure gas refrigerant compressed by the compressor 60; a subcooler 63 that subcools the liquid refrigerant condensed by the condenser 62; a high-pressure expansion valve 64 that expands the liquid refrigerant from the subcooler 63; an economizer 67 connected to the high-pressure expansion valve 64, an intermediate stage of the compressor 60, and a low-pressure expansion valve 65; and an evaporator 66 that evaporates the liquid refrigerant expanded by the low-pressure expansion valve 65.

The compressor 60 is a centrifugal 2-stage compressor, and a constant speed machine to be driven at a constant rotation speed. FIG. 2 exemplifies a constant speed machine; however, a compressor, the rotation speed of which can be variably controlled by an inverter, may be used as the compressor 60. An inlet guide vane (hereinafter, also referred to as “IGV”) 76 is provided at a refrigerant intake port of the compressor 60 to control a refrigerant intake flow rate, and is capable of controlling the capacity of the centrifugal chiller 11.

The condenser 62 is provided with a condensed-refrigerant pressure sensor PC for measuring the pressure of the condensed refrigerant. The subcooler 63 is provided refrigerant flow downstream of the condenser 62 to subcool the condensed refrigerant.

A cooling water pipe 80 is installed in the condenser 62 and the subcooler 63 to cool the condenser 62 and the subcooler 63. The cooling water pipe 80 is connected to a cooling tower 83, and cooling water circulates between the condenser 62, the cooling tower 83, and the subcooler 63 via the cooling water pipe 80. The circulating cooling water absorbs condensation heat (waste heat) from the refrigerant in the condenser 62, radiates the heat in the cooling tower 83, and then is fed to the subcooler 63 again. The heat radiation in the cooling tower 83 is realized by heat exchange between the cooling water and outside air. In this manner, the waste heat radiated when the refrigerant is condensed in the condenser 62 is removed in the cooling tower 83. The cooling water flowing through the cooling water pipe 80 is pressure fed by a cooling water pump 84 installed in the cooling water pipe 80. The cooling water pump 84 is driven by an inverter motor (not illustrated) for the cooling water pump. The rotation speed of the inverter motor is variable, and thus a discharge flow rate of the cooling water pump 84 can be variably controlled.

Chilled water at a rated temperature is obtained by the absorption of heat in the evaporator 66. That is, the chilled water flowing through a chilled water pipe 82 inserted through the evaporator 66 is cooled due to heat of the chilled water being taken away by the refrigerant. The chilled water flowing through the chilled water pipe 82 is pressure fed by a chilled water pump 85 installed in the chilled water pipe 82. The chilled water pump 85 is driven by an inverter motor (not illustrated) for the chilled water pump. The rotation speed of the inverter motor is variable, and thus a discharge flow rate of the chilled water pump 85 can be variably controlled.

A chilled water inlet temperature is measured by a temperature sensor T_in which is installed in the chilled water pipe 82 and in the vicinity of an inlet of the evaporator 66. A chilled water outlet temperature is measured by a temperature sensor T_out which is installed in the chilled water pipe 82 and in the vicinity of an outlet of the evaporator 66.

A hot gas bypass pipe 79 is provided between a gas phase part of the condenser 62 and a gas phase part of the evaporator 66. A hot gas bypass valve 78 is provided to control a flow rate of the refrigerant flowing through the hot gas bypass pipe 79. Because a hot-gas bypass flow rate is adjusted by the hot gas bypass valve 78, it is possible to control the capacity on a very small scale which cannot be satisfactorily controlled by the IGV 76.

In FIG. 2, measured values obtained by various sensors are transmitted to the chiller control device (control device) 50. The chiller control device 50 controls a valve opening degree of the IGV 76 and a valve opening degree of the hot gas bypass valve 78.

In the centrifugal chiller 11 illustrated in FIG. 1, the condenser 62 and the subcooler 63 are provided, and the refrigerant exchanges heat with the cooling water having radiated the waste heat to the outside in the cooling tower 83, and thus the cooling water is warmed up. The centrifugal chiller 11 may be configured such that an air heat exchanger is disposed instead of the condenser 62 and the subcooler 63, and heat exchange between outside air and the refrigerant is carried out in the air heat exchanger. The centrifugal chiller 11 is not limited to having only the cooling function. The centrifugal chiller 11 may have only a heating function, or both of the cooling function and the heat function. A medium which exchanges heat with the refrigerant may be water or air.

The chiller control device 50 includes a central processing unit (CPU); a random access memory (RAM); a read only memory (ROM); and a computer-readable storage medium. A series of processes for realizing various functions are stored in a storage medium in the form of program, and the CPU realizes various functions by reading the program into the RAM, processing information, and executing a calculation process. A form in which the program is preinstalled on the ROM or another storage medium, a form in which the program is stored in a computer-readable storage medium and is supplied to the chiller control device 50, or a form in which the program is delivered to the chiller control device 50 via wired or wireless communication means may be applied. Examples of the computer-readable storage medium are a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a semiconductor memory.

Subsequently, signals and operations of the operation panel and the starting panel will be described with reference to FIGS. 3 and 4 as reference examples.

FIG. 3 is a time chart illustrating signals and operations of the operation panel and the starting panel in a normal state of operation as a reference example. FIG. 4 is a time chart illustrating signals and operations of the operation panel and the starting panel in an abnormal state of operation as a reference example.

The signals and operations of the operation panel and the starting panel will be described with reference to FIG. 3 as a reference example.

In FIG. 3, an operator begins operating the centrifugal chiller 11 by operating the operation panel 20 at a time t₂. At a time t₄, a start instruction for the compressor 60 is output from the operation panel 20 to the starting panel 10, and the starting panel 10 having received the start instruction outputs a start answer (motor start signal) to the operation panel 20, and begins supplying power for starting the motor 72.

An induction electric motor is used as the motor 72. For this reason, right after the start, the motor 72 rotates at a speed lower than the frequency of the commercial power. If the power supply continues to bring the rotation speed of the motor 72 close to the frequency of the commercial power, and a predetermined time period has elapsed, the starting panel 10 determines that the start of the motor 72 has been complete, and outputs a start completion signal to the operation panel 20 (time t₅). For example, the predetermined time period is 5 to 15 seconds.

The operation has continued, and the operator stops operating the centrifugal chiller 11 by operating the operation panel 20 at a time t₁₆. As a result, the compressor start instruction is stopped, and accordingly, the starting panel 10 stops the start answer and the start completion signal, and stops supplying power to the motor 72.

Because the starting panel 10 stops supplying power to the motor 72 in response to a signal from the operation panel 20 when in a normal state of operation, the compressor 60 stops, and the centrifugal chiller 11 stops normally.

Subsequently, the signals and operations of the operation panel and the starting panel in an abnormal state of operation will be described with reference to FIG. 4 as a reference example. The abnormal state of operation indicates a case where the starting panel 10 have not received a stop request output from the centrifugal chiller 11.

Since a beginning process in FIG. 4 is the same as in FIG. 3, a description of the beginning process will be omitted.

The operation has continued, and the operator stops operating the centrifugal chiller 11 by operating the operation panel 20 at the time t₁₆. Accordingly, the compressor start instruction is stopped. Because the compressor start instruction has been stopped, that is, a stop request has been output from the centrifugal chiller 11, but the starting panel 10 has not received the stop request, the starting panel 10 does not stop the start answer and the start completion signal, and continues to supply power to the motor 72.

If a control logic differs between the centrifugal chiller 11 and the starting panel 10, there is a possibility that the starting panel 10 continues to supply power to the motor 72, the compressor 60 also continues to rotate, the centrifugal chiller 11 does not stop, thereby eventually leading to a failure of the compressor 60 or the centrifugal chiller 11.

In the embodiment, the outputting of the start answer and/or the start completion signal while the compressor start instruction is stopped is determined to be abnormal, and a failure state is output.

In the embodiment, control, and the signals and operations of the operation panel and the starting panel will be described with reference to FIGS. 5 and 6.

FIG. 5 is a flowchart illustrating control of a failure state determination unit of the embodiment.

In Step S501, a failure state determination unit 51 determines whether the operation panel 20 has stopped the compressor start instruction. If it is determined that the compressor start instruction has been stopped, the process transitions to Step S502. If it is determined that the compressor start instruction has not been stopped, that is, the compressor 60 is in operation, the process returns to Step S501.

If it is determined that the compressor start instruction has been stopped, it is determined whether the starting panel 10 has stopped the start answer and/or the start completion signal (S502). If it is determined that the start answer and/or the start completion signal have been stopped, the process ends, and if it is determined that the start answer and/or the start completion signal have not been stopped, the process transitions to Step S503.

If it is determined that the start answer and/or the start completion signal have not been stopped, in spite of that the centrifugal chiller 11 is stopped via the operation panel 20, the starting panel 10 does not stop, and the compressor 60 also continues to operate, and thus it is determined that there is an abnormality, and the operation panel 20 outputs a failure state (S503). It is possible to adopt various methods for outputting a failure state such as displaying the failure state on a display, making buzzer sound, and issuing a message. The state may be output to a monitoring facility for the chiller system 1.

FIG. 6 is a time chart illustrating the signals and operations of the operation panel and the starting panel of the embodiment.

In FIG. 6, an operator begins operating the centrifugal chiller 11 by operating the operation panel 20 at the time t₂. A start instruction for the compressor 60 is output from the operation panel 20 to the starting panel 10 at the time t₄. The starting panel 10 having received the start instruction outputs a start answer (motor start signal) to the operation panel 20, and begins supplying power for starting the motor 72. If the start of the motor 72 has been complete, the starting panel 10 outputs a start completion signal to the operation panel 20 (time t₅).

The operation has continued, and the operator stops operating the centrifugal chiller 11 by operating the operation panel 20 at the time t₁₆. Accordingly, the compressor start instruction is stopped. The stop of the compressor start instruction implies that a stop request is output from the centrifugal chiller 11. If the starting panel 10 has not received the stop request, the starting panel 10 does not stop the start answer and the start completion signal, and continues to supply power to the motor 72.

According to the control illustrated in FIG. 5, the failure state determination unit 51 of the chiller control device 50 determines that the start answer and/or the start completion signal have not been stopped, and performs control such that the operation panel 20 outputs a failure state (time t₁₆).

The control device for the chiller system, the chiller system, the control method for the chiller system, and the control program for the chiller system according to the embodiment provide the following effects.

In the embodiment, if the start answer and/or the start completion signal continue to be output after the centrifugal chiller 11 has stopped, an abnormal state is output to the operation panel 20 of the centrifugal chiller 11. Therefore, it is possible to notify an outside system that the compressor 60 continues to rotate after the centrifugal chiller 11 has stopped, and it is possible to notify the operator of the abnormality. Because the operator having received the notification stops the compressor 60 before the compressor 60 becomes damaged, it is possible to properly stop the compressor 60, and to prevent a failure of the centrifugal chiller 11.

Second Embodiment

Hereinbelow, a second embodiment of the present invention will be described with reference to FIGS. 7 to 9.

In the first embodiment, a failure state is output, and in the embodiment, an emergency stop command is output. Because other features are the same as in the first embodiment, the same reference signs will be assigned to the same configuration members, and descriptions of the configuration members will be omitted.

FIG. 7 is a flowchart illustrating control of the failure state determination unit of the embodiment.

In Step S701, the failure state determination unit 51 determines whether the operation panel 20 has stopped the compressor start instruction. If it is determined that the compressor start instruction has been stopped, the process transitions to Step S702. If it is determined that the compressor start instruction has not been stopped, that is, the compressor 60 is in operation, the process returns to Step S701.

If it is determined that the compressor start instruction has been stopped, it is determined whether the starting panel 10 has stopped a start answer and/or a start completion signal (S702). If it is determined that the start answer and/or the start completion signal have been stopped, the process ends, and if it is determined that the start answer and/or the start completion signal have not been stopped, the process transitions to Step S703.

If it is determined that the start answer and/or the start completion signal have not been stopped, in spite of that the centrifugal chiller 11 is stopped via the operation panel 20, the starting panel 10 does not stop, and the compressor 60 also continues to operate, and thus it is determined that there is an abnormality, and the operation panel 20 outputs an emergency stop command (S703). Specifically, a maintained signal which is the emergency stop command is output to the starting panel 10. For this reason, a circuit of the starting panel 10 is required to be designed to receive the emergency stop command which is a maintained signal.

FIG. 8 is a time chart illustrating an operation/stop command and an emergency stop command of the embodiment, and pulse signals as a reference example.

As illustrated in FIG. 8, the operation/stop command of the operation panel 20 of the embodiment is output as a maintained signal. Typically, the operation/stop command becomes ON at a time t_s, and an operation is commanded. Because the maintained signal is a continuous signal, the maintained signal continues to be ON during the operation. The operation/stop command becomes OFF at a time t_s, and a stop is commanded.

As a reference example, in regard to commands given as pulse signals, an operation command becomes ON at the time t_s, and a stop command becomes ON at the time t_e. The pulse signal is a command given as an instantaneous signal, and if a stop command timing is missed, it is not possible to stop the centrifugal chiller 11 or the compressor 60.

For this reason, an emergency stop command (trip command) is added as a maintained signal. If the operation/stop command becomes OFF at the time t_e, if, according to the control illustrated in FIG. 7, it is determined that the start answer and/or the start completion signal have not been stopped, the operation panel 20 outputs a compressor emergency stop command, and the starting panel 10 having received the compressor emergency stop command makes an emergency stop, and stops supplying power to the motor 72 of the compressor 60.

FIG. 9 is a time chart illustrating signals and operations of the operation panel and the starting panel of the embodiment.

In FIG. 9, an operator begins operating the centrifugal chiller 11 by operating the operation panel 20 at the time t₂. At the time t₄, a start instruction for the compressor 60 is output from the operation panel 20 to the starting panel 10, and the starting panel 10 having received the start instruction outputs a start answer (motor start signal) to the operation panel 20, and begins supplying power for starting the motor 72. If the start of the motor 72 has been complete, the starting panel 10 outputs a start completion signal to the operation panel 20 (time t₅).

The operation has continued, and the operator stops operating the centrifugal chiller 11 by operating the operation panel 20 at the time t₁₆. Accordingly, the compressor start instruction is stopped. The stop of the compressor start instruction implies that a stop request is output from the centrifugal chiller 11. If the starting panel 10 has not received the stop request, the starting panel 10 does not stop the start answer and the start completion signal, and continues to supply power to the motor 72.

According to the control illustrated in FIG. 7, the failure state determination unit 51 of the chiller control device 50 determines that the start answer and/or the start completion signal have not been stopped, and performs control such that the operation panel 20 outputs a compressor emergency stop command (time t₁₆). The starting panel 10 having received the compressor emergency stop command makes an emergency stop, and stops supplying power to the motor 72 of the compressor 60 (time t₁₈).

The control device for the chiller system, the chiller system, the control method for the chiller system, and the control program for the chiller system according to the embodiment provide the following effects.

In the embodiment, if the start answer and/or the start completion signal continue to be output after the centrifugal chiller 11 has stopped, because the operation panel 20 of the centrifugal chiller 11 outputs an emergency stop command to the starting panel 10, even though the compressor 60 continues to rotate after the centrifugal chiller 11 has stopped, the starting panel 10 is capable of receiving the emergency stop command, and making an emergency stop. Therefore, it is possible to properly bring the compressor 60 into an emergency stop without an operation of the operator being intervened, and to prevent a failure of the centrifugal chiller 11.

If the emergency stop command is given as a pulse signal, the pulse signal is not received due to a failure, and a stop timing is missed, a stop cannot be made. In the embodiment, because the emergency stop command is given as a maintained signal which is a continuous signal, the starting panel 10 is more likely to receive the signal, and is capable of more properly making a stop.

Third Embodiment

Hereinbelow, a third embodiment of the present invention will be described with reference to FIG. 10.

In the second embodiment, an emergency stop command is output, and in the embodiment, control for protecting the compressor is performed. Because other features are the same as in the second embodiment, the same reference signs will be assigned to the same configuration members, and descriptions of the configuration members will be omitted.

FIG. 10 is a flowchart illustrating control of the failure state determination unit of the embodiment.

In Step S101, the failure state determination unit 51 determines whether the operation panel 20 has stopped a compressor start instruction. If it is determined that the compressor start instruction has been stopped, the process transitions to Step S102. If it is determined that the compressor start instruction has not been stopped, that is, the compressor 60 is in operation, the process returns to Step S101.

If it is determined that the compressor start instruction has been stopped, it is determined whether the starting panel 10 has stopped a start answer and/or a start completion signal (S102). If it is determined that the start answer and/or the start completion signal have been stopped, the process ends, and if it is determined that the start answer and/or the start completion signal have not been stopped, the process transitions to Step S103.

If it is determined that the start answer and/or the start completion signal have not been stopped, in spite of that the centrifugal chiller 11 is stopped via the operation panel 20, the starting panel 10 does not stop, and the compressor 60 also continues to operate, and thus it is determined that there is an abnormality, and the operation panel 20 outputs a failure state (S103).

Subsequently, if the compressor 60 continues to operate, control of each part is performed such that the compressor 60 or other key components of the centrifugal chiller 11 can be protected without chilled water being produced. In Step S104, the chilled water pump 85 provided in the evaporator 66 connected to the compressor 60 continues to operate, and the cooling water pump 84 provided in the condenser 62 continues to operate. If the chilled water pump 85 continues to operate, the chilled water circulates, and if the cooling water pump 84 continues to operate, the cooling water circulates.

Subsequently, in Step S105, an oil pump 90, which is provided in the compressor 60 to supply a lubricant, continues to operate. If the oil pump 90 continues to operate, the lubricant of the compressor 60 circulates.

Subsequently, in Step S106, the IGV 76 of the compressor 60 is controlled such that a chilled water outlet temperature of the centrifugal chiller 11 becomes equal to a chilled water inlet temperature. If the IGV 76 is controlled as described above, the refrigerant circulates, and chilled water is not produced.

In the embodiment, the entire controls in Steps S104 to S106 are performed; however, only any one of the controls may be executed, or a combination of controls may be executed.

The control device for the chiller system, the chiller system, the control method for the chiller system, and the control program for the chiller system according to the embodiment provide the following effects.

In the embodiment, if the start answer and/or the start completion signal continue to be output after the centrifugal chiller 11 has stopped, because the chilled water pump 85 provided in the evaporator 66 continues to operate, and the cooling water pump 84 provided in the condenser 62 continues to operate, it is possible to protect a heat exchanger of the evaporator 66 from freezing without producing chilled water.

In the embodiment, if the start answer and/or the start completion signal continue to be output after the centrifugal chiller 11 has stopped, because the oil pump 90 of the compressor 60 continues to operate, it is possible to restrict the occurrence of lubricant deficiency in the compressor 60. Therefore, it is possible to protect the compressor 60.

In the embodiment, if the start answer and/or the start completion signal continue to be output after the centrifugal chiller 11 has stopped, because the IGV 76 of the compressor 60 is controlled such that the chilled water outlet temperature of the centrifugal chiller 11 becomes equal to the chilled water inlet temperature, it is possible to prevent cooling refrigerant deficiency in the motor 72 of the compressor 60 by continuously controlling the IGV 76 not to produce the chilled water while circulating the refrigerant to the motor 72 of the compressor 60.

The embodiments of the present invention have been described in detail with reference to the drawings; however, a specific configuration is not limited to the configurations in the embodiments, and a design change can be made without departing from the concept of the present invention.

A combination of the embodiments may be realized.

If a combination of the first embodiment and the second embodiment is realized, the following effects can be obtained. If the start answer and/or the start completion signal continue to be output after the centrifugal chiller 11 has stopped, because an abnormal state is output to the operation panel 20, and an emergency stop command is output from the operation panel 20 to the starting panel 10, it is possible to properly bring the compressor 60 into an emergency stop while notifying the operator of the abnormality.

REFERENCE SIGNS LIST

1: chiller system

10: starting panel

11: centrifugal chiller (chiller)

20: operation panel

50: chiller control device (control device)

60: compressor

72: motor

Claims

1-10. (canceled)

11. A control device for a chiller system that is provided with a chiller provided with a compressor rotated by a rotor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor,

wherein the starting panel begins supplying power to the motor of the compressor in response to a start command from the chiller to start the motor, and outputs a motor start signal and a start completion signal to the chiller, and

wherein if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an emergency stop command is output from the operation panel to the starting panel.

12. The control device for a chiller system according to claim 11,

wherein the emergency stop command is a maintained signal.

13. The control device for a chiller system according to claim 11,

wherein if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, a chilled water pump provided in an evaporator connected to the compressor continues to operate, and a cooling water pump provided in a condenser continues to operate.

14. The control device for a chiller system according to claim 11,

wherein if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, an oil pump, which is provided in the compressor to supply a lubricant, continues to operate.

15. The control device for a chiller system according to claim 11,

wherein if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped, a refrigerant control valve of the compressor is controlled such that a chilled water outlet temperature of the chiller becomes equal to a chilled water inlet temperature of the chiller.

16. A chiller system comprising:

the control device for a chiller system according to claim 11.

17. A control method for a chiller system that is provided with a chiller provided with a compressor rotated by a rotor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor, the method comprising:

beginning supplying power to the motor of the compressor from the starting panel in response to a start command from the chiller to start the motor, and outputting a motor start signal and a start completion signal to the chiller from the starting panel; and

outputting an emergency stop command from the operation panel to the starting panel if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped.

18. A control program for a chiller system that is provided with a chiller provided with a compressor rotated by a rotor, an operation panel which is provided in the chiller, operates the chiller, and displays a state of the chiller, and a starting panel which supplies power to the motor and starts the motor, the program comprising:

a step of beginning supplying power to the motor of the compressor from the starting panel in response to a start command from the chiller to start the motor, and of outputting a motor start signal and a start completion signal to the chiller from the starting panel; and

a step of outputting an emergency stop command from the operation panel to the starting panel if the motor start signal and/or the start completion signal continue to be output after the chiller has stopped.