WO2022244192A1 - Refrigeration cycle apparatus - Google Patents

Abstract

A refrigeration cycle apparatus (100) is provided with: a compressor (1) for compressing a refrigerant; an oil separator (2) for separating a refrigerating machine oil from the refrigerant discharged from the compressor (1); an oil feeding path (24) for feeding the refrigerating machine oil separated by the oil separator (7) to the compressor (1); an oil cooler (7) for cooling the refrigerating machine oil to be fed to the compressor (1); a cooling medium path (22) for feeding a cooling medium to the oil cooler (7); a temperature regulator (9) for regulating the temperature of the refrigerating machine oil to be fed to the compressor (1); at least one sensor (15); and a control device (70). The control device (70) controls the temperature regulator on the basis of the detection value of a physical quantity which is detected by the sensor (15) and which changes depending on the temperature of the refrigerating machine oil to be fed to the compressor (1), determines the load state of the compressor (1) on the basis of the detection value of the physical quantity which is detected by the sensor (15) and which is for use in determining the load state of the compressor (1), and, when the load state of the compressor (1) is determined as being an overload state, performs first control for inhibiting increase of operation capacity of the compressor (1) and second control for inhibiting decrease of regulation capacity of the temperature regulator (3).

Description

refrigeration cycle equipment

The present disclosure relates to a refrigeration cycle device.

Conventional refrigeration cycle devices generally detect physical quantities such as the compressor discharge temperature, the compressor discharge pressure, the condensing pressure in the condenser, the operating current of the compressor, and the degree of suction superheat of the compressor. The compressor discharge temperature is the temperature of the refrigerant gas discharged from the compressor. The compressor discharge pressure is the pressure of the refrigerant gas discharged from the compressor.

In a conventional refrigeration cycle apparatus, a threshold value is set for the physical quantity to be detected so as to allow stable operation of the equipment constituting the refrigeration cycle apparatus. I judge. The refrigeration cycle apparatus performs protective control to reduce the load by reducing the operating capacity of the compressor in order to protect the equipment when it is determined that the apparatus is in an overloaded state. The operating capacity of the compressor is the operating capacity of the compressor based on the operating frequency of the compressor or a mechanical capacity control mechanism. The operating capacity of the compressor increases as the operating frequency of the compressor increases. The operating capacity of the compressor is reduced in response to lowering the operating frequency of the compressor.

As an example of protection control, Patent Document 1 discloses that the operating current of the compressor and the temperature of the casing of the compressor are detected, and when the detected temperature exceeds the set temperature, the setting of the operating current is lowered. It is described that an excessive rise in compressor temperature and operating current is thereby prevented.

In Patent Document 2, as a conventional refrigeration cycle device, refrigerating machine oil discharged together with refrigerant from a compressor is separated by an oil separator, the separated refrigerating machine oil is cooled by an oil cooler that cools the refrigerant, and the compressor is In the configuration of injecting refrigerant into the intermediate pressure chamber of the compressor, there is described controlling an electronic expansion valve that adjusts the amount of refrigerant supplied to the oil cooler. In Patent Document 2, the discharge temperature of the compressor is detected, and the electronic expansion valve is controlled so that the detected discharge temperature becomes the target temperature.

JP-A-61-272555 JP 2011-149565 A

However, in conventional refrigeration cycle devices such as those described in Patent Documents 1 and 2, the control of the electronic expansion valve used to cool the refrigerating machine oil is executed independently of the protection control. Therefore, during the execution of the protection control, if the discharge temperature of the compressor drops below the target temperature for controlling the electronic expansion valve in response to the reduction of the operating capacity of the compressor, regardless of the protection control, Since the electronic expansion valve is controlled to raise the discharge temperature of the compressor, the protection control is disturbed. When such control is performed, the load that should be reduced by the protection control is increased by the control of the electronic expansion valve, which causes the problem that the protection control is repeatedly performed. Then, when the protection control is repeatedly executed, the refrigeration cycle apparatus continues to operate in a state where the operating capacity of the compressor is insufficient.

The refrigeration cycle apparatus of the present disclosure is intended to solve the above problems, and aims to obtain a refrigeration cycle apparatus capable of stabilizing the operating state.

The present disclosure relates to a refrigeration cycle device. A refrigeration cycle device includes a compressor that compresses a refrigerant, an oil separator that separates the refrigerant discharged from the compressor and refrigerating machine oil, and an oil supply path that supplies the refrigerating machine oil separated by the oil separator to the compressor. an oil cooler for cooling the refrigerating machine oil supplied to the compressor; a cooling medium path for supplying the cooling medium to the oil cooler; a temperature adjusting device for adjusting the temperature of the refrigerating machine oil supplied to the compressor; A sensor and a controller are provided. The control device controls the temperature adjustment device based on the detected value of the physical quantity that changes with the temperature of the refrigerating machine oil supplied to the compressor detected by the sensor, and determines the load state of the compressor detected by the sensor. determines the load state of the compressor based on the detected value of the physical quantity used for At the same time, a second control is performed to suppress a decrease in the adjustment capacity of the temperature adjustment device.

According to the refrigeration cycle device of the present disclosure, the control device controls the temperature adjustment device based on the detected value of the physical quantity that changes with the temperature of the refrigeration oil supplied to the compressor, and determines the load state of the compressor. When an overload state is determined based on the detected value of the physical quantity used, first control is performed to suppress an increase in the operating capacity of the compressor, and second control is performed to suppress a decrease in the adjustment capacity of the temperature adjustment device. By doing so, the first control for suppressing an increase in the operating capacity of the compressor and the second control for suppressing a decrease in the adjustment capacity of the temperature adjustment device are executed in association with each other. As a result, when the compressor is overloaded, the first control that suppresses the increase in the operating capacity of the compressor is not hindered by the control of the adjustment capacity of the temperature adjustment device. can stabilize the operating state of the

1 is an overall configuration diagram of a refrigeration cycle apparatus 100 of Embodiment 1. FIG. 3 is a block diagram showing an example of control configuration of the refrigeration cycle apparatus 100; FIG. It is a figure which shows the relationship between the load amount in protection control, and the content of protection control. 4 is a flowchart showing an example of protection control; 4 is a flow chart showing a first control example of valve opening reduction suppression control in Embodiment 1. FIG. 7 is a flow chart showing a second control example of valve-opening-degree-decrease suppression control in Embodiment 1. FIG. 10 is a flow chart showing an example of valve opening reduction suppression control in Embodiment 2. FIG. 1 is an overall configuration diagram of a brine chiller device 101. FIG. 3 is a block diagram showing an example of control configuration of the brine chiller device 101. FIG. 11 is a flow chart showing valve opening reduction suppression control in Embodiment 3. FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. A plurality of embodiments will be described below, but appropriate combinations of the configurations described in the respective embodiments have been planned since the filing of the application. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

Embodiment 1.
[Overall Configuration of Refrigeration Cycle Device 100]
FIG. 1 is an overall configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 1. FIG. Note that FIG. 1 functionally shows the connection relationship and arrangement configuration of each device in the refrigeration cycle apparatus 100, and does not necessarily show the arrangement in a physical space.

A refrigeration cycle device 100 shown in FIG. 1 is an air-cooled refrigerator equipped with a two-stage compressor 1 . The refrigeration cycle device 100 includes a compressor 1, an oil separator 2, an air-cooled condenser 3, an intercooler 4, a main liquid expansion valve 5, an evaporator 6, an oil cooler 7, an intercooling electronic expansion valve 8, and an oil cooler. electronic expansion valve 9 for motor cooling, electronic expansion valve 10 for motor cooling, suction temperature sensor 11, suction pressure sensor 12, intermediate pressure sensor 13, discharge pressure sensor 14, discharge temperature sensor 15, outlet liquid temperature sensor 16, outlet gas temperature sensor 17 , oil supply temperature sensor 18, outlet gas temperature sensor 19, main refrigerant pipe 20, intermediate cooler refrigerant pipe 21, oil cooler refrigerant pipe 22, motor cooler refrigerant pipe 23, oil supply pipe 24, evaporation pressure sensor 27, and outlet A gas temperature sensor 28 is included.

In the refrigeration cycle device 100, the compressor 1, the air-cooled condenser 3, the main liquid expansion valve 5, and the evaporator 6 constitute a basic refrigeration cycle. In the refrigeration cycle device 100, the refrigerant mainly flows through the compressor 1, the oil separator 2, the air-cooled condenser 3, the intercooler 4, the main liquid expansion valve 5, and the main refrigerant pipe 20, which is a route passing through the evaporator 6. be circulated. In addition to these routes, in the refrigeration cycle apparatus 100 , the refrigerant is also circulated through the intermediate cooler refrigerant pipe 21 , the oil cooler refrigerant pipe 22 , and the motor cooler refrigerant pipe 23 branched from the main refrigerant pipe 20 .

The refrigeration cycle device 100 further includes a control device (the control device 70 shown in FIG. 2) that controls the equipment that configures the refrigeration cycle device 100 . The compressor 1 is provided with an inverter (not shown) for driving the compressor 1 . A blower 30 is provided in the air-cooled condenser 3 . A blower 60 is provided in the evaporator 6 .

The evaporator 6 is installed in the freezer warehouse 25 as an indoor unit. A heat source device that houses the compressor 1 and the air-cooled condenser 3 is installed outdoors as an outdoor unit. The freezer warehouse 25 is provided with an internal temperature sensor 26 that detects the temperature inside the freezer warehouse.

The suction temperature sensor 11 detects the suction temperature of the compressor 1 . A suction pressure sensor 12 detects the suction pressure of the compressor 1 . Intermediate pressure sensor 13 detects the pressure in the intermediate chamber of compressor 1 . A discharge pressure sensor 14 detects the discharge pressure of the compressor 1 . A discharge temperature sensor 15 detects the discharge temperature of the compressor 1 . The outlet liquid temperature sensor 16 detects the outlet temperature of the main refrigerant in the intercooler 4 . The outlet gas temperature sensor 17 detects the outlet temperature of the gasified refrigerant supplied from the intercooling electronic expansion valve 8 in the intercooler 4 . A supply oil temperature sensor 18 detects the supply temperature of the refrigerating machine oil coming out of the oil cooler 7 . The outlet gas temperature sensor 19 detects the outlet temperature of the gasified refrigerant supplied from the oil cooling electronic expansion valve 9 in the oil cooler 7 . Evaporation pressure sensor 27 detects the evaporation pressure in evaporator 6 . An outlet gas temperature sensor 28 detects the outlet temperature of gasified refrigerant in the evaporator 6 .

The control device stores the set temperature set by the user using a remote control (not shown), compares the internal temperature detected by the internal temperature sensor 26 with the stored set temperature, and based on the comparison result , to determine whether to operate or stop the refrigerator.

[Example of operation of refrigeration cycle device 100]
Next, the operation of the refrigeration cycle apparatus 100 in cooling operation will be described.

The high-temperature and high-pressure refrigerant gas and refrigerating machine oil discharged from the compressor 1 are separated into refrigerant gas and refrigerating machine oil in the oil separator 2 . Refrigerant gas separated in the oil separator 2 flows into the air-cooled condenser 3 . In the air-cooled condenser 3, due to the operation of the inverter-driven blower 30, heat is exchanged between the inflowing refrigerant gas and the outside air, and the refrigerant gas is condensed into a liquid refrigerant. The liquid refrigerant exiting the air-cooled condenser 3 is cooled in the intercooler 4 . In the intercooler 4, the mainstream liquid refrigerant increases the degree of supercooling.

The liquid refrigerant that has exited the intercooler 4 is decompressed when passing through the main liquid expansion valve 5 to become a low-pressure two-phase refrigerant. The low-pressure two-phase refrigerant flows into the evaporator 6 . In the evaporator 6, heat is exchanged between the air inside the freezer warehouse 25 and the refrigerant by the inverter-driven blower 60, whereby the two-phase refrigerant evaporates into refrigerant gas. Refrigerant gas leaving the evaporator 6 is sucked into the compressor 1 . In this way, the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil separator 2, the air-cooled condenser 3, the intercooler 4, the main liquid expansion valve 5, and the evaporator 6. A refrigerant cycle is completed in the refrigerant pipe 20 . A refrigerant that circulates in such a refrigerant cycle is called a mainstream refrigerant.

A main refrigerant pipe 20 between the intercooler 4 and the evaporator 6 branches into an intercooler refrigerant pipe 21 , an oil cooler refrigerant pipe 22 , and a motor cooler refrigerant pipe 23 . The intercooler refrigerant pipe 21 is provided so as to reach the intermediate chamber of the compressor 1 from the branch position of the main refrigerant pipe 20 via the intercooling electronic expansion valve 8 and the intercooler 4 . The oil cooler refrigerant pipe 22 is provided so as to reach an intermediate chamber of the compressor 1 from a branch position in the mainstream refrigerant pipe 20 via the oil cooling electronic expansion valve 9 and the oil cooler 7 . The motor cooler refrigerant pipe 23 is provided so as to reach the motor chamber of the compressor 1 from a branch position in the mainstream refrigerant pipe 20 via the motor cooling electronic expansion valve 10 .

In the intercooler 4, the liquid refrigerant is cooled by heat exchange between the two-phase refrigerant decompressed by the electronic expansion valve 8 for intercooling and the main liquid refrigerant. In the intercooler 4, the two-phase refrigerant is gasified. The gasified refrigerant coming out of the intercooler 4 passes through the intercooler refrigerant pipe 21 and flows into the intermediate chamber of the compressor 1 . In the oil cooler 7, the two-phase refrigerant pressure-reduced by the oil-cooling electronic expansion valve 9 exchanges heat with the refrigerating machine oil coming out of the oil separator 2, thereby cooling the refrigerating machine oil. In the oil cooler 7, the two-phase refrigerant is gasified. The gasified refrigerant coming out of the oil cooler 7 passes through the oil cooler refrigerant pipe 22 and flows into the intermediate chamber of the compressor 1 . On the other hand, the refrigerating machine oil cooled by the oil cooler 7 is supplied from the oil cooler 7 to the compressor 1 through the oil supply pipe 24 . The two-phase refrigerant decompressed by the motor cooling electronic expansion valve 10 flows through the motor cooler refrigerant pipe 23 into the motor chamber of the compressor 1 to cool the motor. The oil-cooling electronic expansion valve 9 functions as a temperature adjustment device that adjusts the temperature of the refrigerating machine oil supplied to the compressor 1 by adjusting the valve opening.

[Control configuration example]
Next, a control configuration example of the refrigeration cycle apparatus 100 will be described. FIG. 2 is a block diagram showing a control configuration example of the refrigeration cycle apparatus 100. As shown in FIG.

The control device 70 includes a CPU (Central Processing Unit) 71, a memory 72 (ROM (Read Only Memory) and RAM (Random Access Memory)), an input/output buffer (not shown) for inputting and outputting various signals, etc. Consists of The CPU 71 develops a program stored in the ROM into the RAM or the like and executes it. The program stored in the ROM is a program in which processing procedures of the control device 70 are described. The controller 70 controls each device in the refrigeration cycle apparatus 100 according to these programs. This control is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.

In the control device 70, a suction temperature sensor 11, a suction pressure sensor 12, an intermediate pressure sensor 13, a discharge pressure sensor 14, a discharge temperature sensor 15, an outlet liquid temperature sensor 16, an outlet gas temperature sensor 17, an oil supply temperature sensor 18, an outlet gas Detection signals from the temperature sensor 19, the internal temperature sensor 26, the evaporating pressure sensor 27, and the outlet gas temperature sensor 28 are input.

In the control device 70, the compressor 1, the oil separator 2, the air-cooled condenser 3, the main liquid expansion valve 5, the intermediate cooling electronic expansion valve 8, the oil cooling electronic expansion valve 9, and the motor cooling electronic expansion valve 10, and outputs a control signal to each of them.

Next, an example of control of actuators such as the compressor 1 by the CPU 71 of the control device 70 will be described. In the following, as an example of control, an example of control in the case of executing proportional control in which actuators are operated at regular time intervals will be described. Such control that is executed at regular time intervals is called regular control.

The control device 70 executes the following control regarding the compressor 1. The control device 70 compares the target evaporation temperature stored in advance in the memory 72 with the saturation temperature conversion value of the suction pressure detected by the suction pressure sensor 12, that is, the evaporation temperature, and determines the evaporation temperature based on the detected value of the suction pressure. is the target evaporation temperature, the operating frequency (rotational speed) of the compressor 1 is controlled at regular time intervals. For example, if the evaporating temperature based on the detected value is higher than the target evaporating temperature, the controller 70 increases the operating frequency of the compressor 1 to increase the cooling capacity. Controlling the operating frequency of the compressor 1 in this way is performed to adjust the cooling or heating capacity, and is therefore called capacity adjustment or capacity control.

The control device 70 performs the following control on the blower 30 of the air-cooled condenser 3. The controller 70 determines the condensing temperature based on the detected value of the discharge pressure based on the difference between the target condensing temperature stored in advance in the memory 72 and the condensing temperature, which is the saturation temperature corresponding to the discharge pressure detected by the discharge pressure sensor 14. is the target condensing temperature, the frequency of the blower 30 of the air-cooled condenser 3 is controlled at regular time intervals. For example, if the condensing temperature based on the detected value is higher than the target condensing temperature, the controller 70 increases the frequency of the fan 30, and if the condensing temperature based on the detected value is lower than the target condensing temperature, the control device 70 increases the frequency of the fan 30. Decrease.

The control device 70 performs the following control on the blower 60 of the evaporator 6. The control device 70 compares the internal temperature detected by the internal temperature sensor 26 with the set temperature set by the user using the remote controller, and controls the start/stop of the blower of the evaporator 6 . For example, when the cooling operation is required, electric power is supplied to the motor of the blower 60 to operate the blower 60, and when the compressor 1 is stopped, the electric power supplied to the motor of the blower 60 is cut off to operate the blower 60. stop.

The control device 70 performs the following control on the intermediate cooling electronic expansion valve 8. The control device 70 calculates the intercooler superheat degree, which is the difference between the intercooler outlet gas temperature detected by the outlet gas temperature sensor 17 and the saturation temperature corresponding to the intermediate pressure detected by the intermediate pressure sensor 13. Based on the difference between the degree of superheat of the intercooler and the target degree of superheat of the intercooler pre-stored in the memory 72 of the control device 70, the degree of superheat of the intercooler based on the detected value of the cooler outlet gas temperature reaches the target intercooling The degree of valve opening of the electronic expansion valve 8 for intercooling is obtained by calculation so as to obtain the superheat degree of the unit, and the control to operate the electronic expansion valve 8 for intermediate cooling so as to achieve the degree of valve opening is executed at regular time intervals. do.

The control device 70 performs the following control on the oil cooling electronic expansion valve 9. Based on the difference between the discharge temperature detected by the discharge temperature sensor 15 and the target discharge temperature stored in advance in the memory 72 of the control device 70, the control device 70 adjusts the detected discharge temperature to the target discharge temperature. The valve opening degree of the cooling electronic expansion valve 9 is obtained by calculation, and control is executed at regular time intervals to operate the oil cooling electronic expansion valve 9 so as to achieve the valve opening degree.

The control device 70 performs the following control on the motor cooling electronic expansion valve 10. Based on the difference between the motor room temperature detected by the motor room temperature sensor (not shown) and the target motor room temperature pre-stored in the memory 72 of the control device 70, the control device 70 sets the detected motor room temperature to the target motor temperature. The valve opening degree of the motor cooling electronic expansion valve 10 is calculated to obtain the room temperature, and control is performed at regular time intervals to operate the motor cooling electronic expansion valve 10 so as to achieve the valve opening degree. .

The control device 70 performs the following control on the main liquid expansion valve 5. The control device 70 controls the evaporator outlet gas temperature detected by the outlet gas temperature sensor 28, the saturation temperature corresponding to the evaporation pressure detected by the evaporation pressure sensor 27, that is, the evaporator superheat, which is the difference between the evaporation temperature, Based on the difference from the target evaporator superheat degree stored in advance in the memory 72 of the control device 70, the evaporator superheat degree based on the evaporating pressure detected by the evaporating pressure sensor 27 becomes the target evaporator superheat degree. The valve opening degree of the liquid expansion valve 5 is obtained by calculation, and control is performed at regular time intervals to operate the main liquid expansion valve 5 so as to achieve the valve opening degree.

The control method for each actuator shown above is a general one, and other control methods may be used as the control method for each actuator.

[Example of protection control]
Next, an example of protection control will be described.

A state in which the amount of load applied to the compressor 1 is excessive is called an overload state. The load amount can be obtained based on the discharge temperature detected by the discharge temperature sensor 15, for example. Specifically, it is determined that the load amount increases as the discharge temperature detected by the discharge temperature sensor 15 increases. When the compressor 1 is overloaded, the discharge temperature of the compressor 1 may rise abnormally, causing an abnormal condition such as seizure of the compressor 1 .

When the compressor 1 is overloaded, in order to protect the compressor 1, which may cause an abnormal condition, the physical quantities related to the compressor 1, such as temperature, pressure, and operating current, are controlled to prevent an abnormal condition from occurring. Protection control is performed to suppress an increase in the operating capacity of the compressor 1 with the aim of keeping the operating capacity of the compressor 1 below an allowable value for the state. The operating capacity of the compressor 1 is a value indicating the operating capacity such as the discharge capacity of the compressor 1 . The control device changes the operating capacity of the compressor 1 by changing the rotation speed of the compressor 1 with the inverter. In protection control for suppressing an increase in the operating capacity of the compressor 1, at least one of maintaining the operating capacity of the compressor 1 and decreasing the operating capacity of the compressor 1 is executed.

FIG. 3 is a diagram showing the relationship between the amount of load and the content of protection control in protection control. In the protection control executed by the control device 70, two stages of protection control are executed. The load amount can be indicated based on the discharge temperature detected by the discharge temperature sensor 15, for example. Specifically, when the load increases, the operating frequency of the compressor 1 increases, and the discharge temperature detected by the discharge temperature sensor 15 tends to increase. Accordingly, it can be determined that the load amount of the compressor 1 increases as the discharge temperature detected by the discharge temperature sensor 15 increases.

In FIG. 3, the load amount is determined based on the discharge temperature detected by the discharge temperature sensor 15, for example. As the load increases, the discharge temperature detected by the discharge temperature sensor 15 increases. In the protection control, the load amount threshold used for determining whether or not to perform the protection control is a first load amount upper limit value that is a first threshold value, and a load amount lower than the first load amount upper limit value. A second load amount upper limit, which is a second threshold, is set. Since the load amount is determined based on the discharge temperature detected by the discharge temperature sensor 15 , the first load amount upper limit value and the second load amount upper limit value are defined by the discharge temperature of the compressor 1 . For example, when the allowable upper limit value of the discharge temperature of the compressor 1 is 100°C, the first load amount upper limit value is set to 90°C, and the second load amount upper limit value is set to 85°C.

In the protective control executed by the control device 70, when the discharge temperature detected by the discharge temperature sensor 15 is less than the second load amount upper limit value, the protective control is not executed (unexecuted state or canceled state). When the discharge temperature detected by the discharge temperature sensor 15 becomes equal to or higher than the second load upper limit value and less than the first load amount upper limit value due to reasons such as an increase in the discharge temperature during operation of the compressor 1, compression A second protection control that prohibits increasing the operating capacity of the machine 1 is executed. Then, when the discharge temperature detected by the discharge temperature sensor 15 becomes equal to or higher than the first load amount upper limit value due to a sudden rise in the discharge temperature or a change in the operating state during the operation of the compressor 1. reduces the working capacity of the compressor 1 . A first protection control is executed.

Thus, in the protection control performed by the control device 70, two stages of protection control, the first protection control and the second protection control, with different control contents are performed based on the magnitude of the load amount. Such first protection control and second protection control are common in that they are protection controls that suppress an increase in the operating capacity of the compressor. When such protective control that suppresses an increase in the operating capacity of the compressor is executed, the oil cooling electronic expansion valve that functions as a temperature adjustment device for the refrigerating machine oil supplied to the compressor 1 as well as the protective control 9 is executed to suppress a decrease in the valve opening degree. Since the valve opening degree is the degree of operation for adjusting the capacity of the valve, it can be said that it is the degree of operation for adjusting the capacity of the temperature control device comprising the oil cooling electronic expansion valve 9 . Therefore, the valve-opening-degree reduction suppression control can also be said to be adjustment-capacity suppression control for suppressing a decrease in the adjustment capacity (valve-opening degree) of the temperature adjustment device.

[Control contents of protection control and valve opening reduction suppression control]
Next, the control contents of the protection control and the valve opening reduction suppression control executed by the CPU 71 of the control device 70 will be described.

(Example of protection control)
FIG. 4 is a flowchart showing an example of protection control. In protection control, the CPU 71 executes the following processes.

In step S1, it is determined whether or not the load amount based on the discharge temperature detected by the discharge temperature sensor 15 is equal to or higher than the second load amount upper limit value (85°C). Specifically, in step S1, it is determined whether or not the detected discharge temperature is equal to or higher than the second load amount upper limit temperature, thereby determining whether the load amount is equal to or higher than the second load amount upper limit value. to decide.

If it is determined in step S1 that the load amount is equal to or greater than the second load amount upper limit value, in step S2, the second protection control that prohibits an increase in the operating capacity of the compressor 1 is executed. Specifically, in step S2, an increase in the operating frequency of the compressor 1 is prohibited.

Next, in step S3, it is determined whether or not the load amount based on the detected value of the discharge temperature is equal to or higher than the first load amount upper limit value (90°C). Specifically, in step S3, it is determined whether or not the detected discharge temperature is equal to or higher than the temperature of the first load amount upper limit value, thereby determining whether or not the load amount is equal to or higher than the first load amount upper limit value. to decide.

If it is determined in step S3 that the load amount is equal to or greater than the first load amount upper limit value, in step S4, the first protection control for reducing the operating capacity of the compressor 1 is executed. Specifically, in step S4, the operating frequency of the compressor 1 is lowered.

If it is determined in step S1 described above that the load is not equal to or greater than the second load amount upper limit value, it means that the condition for executing the protection control is not satisfied. It is determined whether or not the operating capacity is suppressed due to the execution of protection control including protection control.

If it is determined in step S5 that the operating capacity is not suppressed, return. On the other hand, if it is determined in step S5 that the operating capacity is being suppressed, then in step S6, the operating capacity is released from the suppressed state, and the process returns. Specifically, in step S6, the protection control being executed is terminated.

In the protection control shown in FIG. 4, when the load capacity of the compressor 1 is greater than or equal to the second load amount upper limit value and less than the first load amount upper limit value, step S2 prohibits an increase in the operating capacity of the compressor 1. When the second protection control is executed and the load capacity of the compressor 1 is equal to or greater than the first load amount upper limit value, the first protection control for reducing the operating capacity of the compressor 1 is executed in step S4. As a result, in the protection control, when the load capacity of the compressor 1 is determined to be in an overload state, the first control that suppresses the increase in the operating capacity of the compressor 1 is executed.

Next, a control example of valve opening reduction suppression control will be described. A first control example and a second control example will be described as control examples of the valve opening reduction suppression control.

(First control example of valve opening reduction suppression control)
FIG. 5 is a flow chart showing a first control example of valve-opening reduction suppression control according to the first embodiment. Valve-opening degree reduction suppression control is executed in conjunction with execution of protection control. In the first control example of the valve opening reduction suppression control, the CPU 71 executes the following processing.

In step S11, it is determined whether or not an increase in the operating capacity of the compressor 1 is currently prohibited by protection control. Specifically, in step S11, it is determined whether or not the second protection control executed in step S2 is being performed, thereby determining whether or not the increase in the operating capacity of the compressor 1 is being prohibited. .

If it is determined in step S11 that the operating capacity of the compressor 1 is prohibited from being increased, then in step S12, the reduction in opening of the oil cooling electronic expansion valve 9 is prohibited. For example, if the valve opening degree calculated in the regular control of the oil cooling electronic expansion valve 9 is a value that reduces the valve opening degree, the control signal for operating the oil cooling electronic expansion valve 9 is not output. On the other hand, when the valve opening degree calculated in the regular control of the oil cooling electronic expansion valve 9 is a value for increasing the valve opening degree, a control signal for operating the oil cooling electronic expansion valve 9 is output. In this way, in step S12, the reduction in the valve opening degree of the oil cooling electronic expansion valve 9 is suppressed.

As described above, in step S12, control for decreasing the valve opening degree is prohibited in the regular control of the oil cooling electronic expansion valve 9 . When the control for reducing the valve opening degree of the oil cooling electronic expansion valve 9 is prohibited, the temperature of the refrigerating machine oil adjusted by the oil cooling electronic expansion valve 9 is maintained, thereby suppressing the temperature rise of the refrigerating machine oil. be done.

In step S13, it is determined whether or not the operating capacity of the compressor 1 is currently decreasing due to protection control. Specifically, in step S13, it is determined whether or not the operating capacity of the compressor 1 is decreasing by determining whether or not the first protection control executed in step S4 is being performed. .

If it is determined in step S13 that the operating capacity is not in a decreasing state, return. on the other hand. If it is determined in step S13 that the operating capacity is decreasing, in step S14 control is executed to increase the valve opening of the oil cooling electronic expansion valve 9, and the routine returns. Specifically, in step S14, control is executed to increase the valve opening by a constant opening stored in the memory 72 in advance. In addition, in step S14, control may be executed to increase the valve opening by the opening obtained by multiplying the current valve opening by a constant rate stored in advance in the memory 72 . Thus, in step S14, the valve opening degree of the oil cooling electronic expansion valve 9 is suppressed.

Thus, in step S14, control for increasing the valve opening degree of the oil cooling electronic expansion valve 9 is executed in accordance with the execution of the first protection control. When the control for increasing the opening degree of the oil cooling electronic expansion valve 9 is executed, the temperature of the refrigerating machine oil adjusted by the oil cooling electronic expansion valve 9 can be lowered, thereby suppressing the temperature rise of the refrigerating machine oil. can be Specifically, in step S14, the valve opening degree of the oil cooling electronic expansion valve 9 is increased by a fixed amount stored in the memory 72. FIG.

If it is determined in step S11 that the increase in the operating capacity of the compressor 1 is not prohibited, in step S15, the valve opening of the oil cooling electronic expansion valve 9 is suppressed in step S12 or step S14. It is determined whether or not it is in the state of

If it is determined in step S15 that the valve opening degree of the oil cooling electronic expansion valve 9 is not being suppressed, the process returns. On the other hand, if it is determined in step S15 that the valve opening degree of the oil cooling electronic expansion valve 9 is being suppressed, step After S12 or S14 starts execution of a state in which the degree of opening of the oil cooling electronic expansion valve 9 is suppressed, the protection control being executed ends in Step S6. If it is determined in step S15 that the valve opening degree of the oil cooling electronic expansion valve 9 is being suppressed, then in step S16, the valve opening degree of the oil cooling electronic expansion valve 9 is reduced by step S12 or step S14. End the suppressed state and return. As a result, the state in which the degree of opening of the oil-cooling electronic expansion valve 9 is suppressed, which has been executed along with the termination of the protection control, is terminated in response to the termination of the protection control.

(Second control example of valve opening reduction suppression control)
FIG. 6 is a flow chart showing a second control example of valve opening reduction suppression control according to the first embodiment. In the second control example of the valve opening reduction suppression control, the CPU 71 executes the following processing.

The second control example shown in FIG. 6 differs from the first control example shown in FIG. 5 in step S15a. Step S15a is executed when it is determined in step S15 that the valve opening degree of the oil cooling electronic expansion valve 9 is being suppressed. In step S15a, it is determined whether or not the load amount based on the discharge temperature detected by the discharge temperature sensor 15 is less than the third load amount upper limit value. The third load amount upper limit is set to a load amount lower than the second load amount upper limit. The third load amount upper limit is set to 80° C., which is lower than the second load amount upper limit of 85° C., for example. Specifically, in step S15a, it is determined whether the load amount is less than the third load amount upper limit value by determining whether the detected discharge temperature is less than the temperature of the third load amount upper limit value. to decide.

If it is determined in step S15a that it is not less than the third load amount upper limit value, return. On the other hand, if it is determined in step S15a that the load amount is less than the third upper limit value, in step S16, the state in which the valve opening degree of the oil cooling electronic expansion valve 9 is suppressed in step S12 or step S14 is ended. , to return. As a result, after the protection control ends, when the load amount of the compressor 1 reaches the third load amount upper limit value lower than the second load amount upper limit value, the protective control is executed along with the ended protection control. The state in which the valve opening degree of the oil cooling electronic expansion valve 9 is suppressed ends.

In the second control example of such valve opening reduction suppression control, after the protection control ends, the load amount of the compressor 1 reaches the third load amount upper limit value lower than the second load amount upper limit value. Accordingly, the state in which the degree of valve opening of the oil cooling electronic expansion valve 9 is suppressed, which has been executed along with the finished protection control, ends. Since the state in which the degree of opening of the valve 9 is suppressed ends, when the operating capacity of the compressor 1 increases thereafter, it is possible to make it difficult for the protection control to be executed again. Thereby, the operating state of the refrigeration cycle apparatus can be stabilized more.

In Embodiment 1, the refrigerator is configured to include load-side devices such as the main liquid expansion valve 5 and the evaporator 6. It is also possible to apply the protection control and the valve-opening reduction suppression control described above. Furthermore, even in a compression unit that does not have the air-cooled condenser 3, it is possible to apply the above-described protection control and valve opening reduction suppression control. That is, even when the user purchases the condensing unit or compression unit, the load side device and the air-cooled condenser 3, and completes the refrigeration cycle device in the user's equipment, the protection control and valve opening degree described above Decrease suppression control can be applied.

In Embodiment 1, it is assumed that the control device 70 has a single configuration. good. The load-side controller is electrically connected to the main liquid expansion valve 5, the evaporator 6, the internal temperature sensor 26, and the condensing unit, which are the load-side devices, and detects the detected value of the internal temperature sensor 26 and the setting. Based on the temperature, the outdoor unit (condensing unit) and load side equipment are controlled. In this case, the main liquid expansion valve 5 is controlled by the load side controller. An electronic expansion valve provided in the condensing unit is controlled by the controller of the condensing unit.

In the first embodiment described above, protection control that suppresses an increase in the operating capacity of the compressor 1 and valve opening reduction suppression control that suppresses an increase in the temperature of the refrigerating machine oil are executed in association with each other. As a result, when the compressor 1 is overloaded, the protection control for suppressing an increase in the operating capacity of the compressor 1 is prevented by controlling the temperature of the refrigerating machine oil using the oil-cooling electronic expansion valve 9. Therefore, it is possible to prevent the protection control from being repeatedly executed and the operating capacity of the compressor 1 from becoming insufficient due to the protection control, so that the operating state of the refrigeration cycle apparatus 100 can be stabilized. .

Embodiment 2.
In the first embodiment, an example has been described in which protection control and valve opening reduction suppression control are performed simply depending on whether the vehicle is in an overload state. In the second embodiment, when the operating capacity of the compressor 1 is increased by capacity control, the overload state is determined by the protection control as shown in FIG. Other control examples to be executed will be described. The capacity control increases the operating capacity of the compressor 1 when the evaporating temperature exceeds the aforementioned target evaporating temperature. The state in which the operating capacity of the compressor 1 increases includes operation when the user lowers the set temperature using the aforementioned remote controller, and when the user changes the operating capacity mode such as the intensity of operation using the remote controller. including driving of

The second embodiment is premised on executing the protection control shown in the first embodiment in a configuration similar to the hardware configuration shown in the first embodiment.

FIG. 7 is a flow chart showing an example of valve opening reduction suppression control in the second embodiment. In FIG. 7, the same step numbers are used for the steps that perform the same processing as the valve opening reduction suppression control shown in FIGS. In the valve opening reduction suppression control of FIG. 7, the CPU 71 executes the following processing.

In step S10, it is determined whether or not the operating capacity of the compressor 1 is being increased by controlling the operating capacity. When it is determined in step S10 that the operating capacity of the compressor 1 is not being increased by controlling the operating capacity, in step S17, the same processing as the control shown in FIG. 5 or the same control as the control shown in FIG. process and return. As a result, when the operating capacity of the compressor 1 is not being increased by controlling the operating capacity, the valve opening reduction suppression control described above with reference to FIG. 5 or 6 is executed.

On the other hand, if it is determined in step S10 that the operating capacity of the compressor 1 is being increased by controlling the operating capacity, it is determined in step S11 whether or not the increase in the operating capacity of the compressor 1 is currently being prohibited by protection control. determine whether

If it is determined in step S11 that the operating capacity of the compressor 1 is prohibited from being increased, the timer T1 is reset in step S11a. The timer T1 is a timer that measures the elapsed time from the end of protection control. At step S12, the reduction of the valve opening degree of the oil cooling electronic expansion valve 9 is prohibited. In step S13, it is determined whether or not the operating capacity of the compressor 1 is currently decreasing due to protection control.

If it is determined in step S13 that the operating capacity is decreasing due to protection control, then in step S13a the valve opening of the oil cooling electronic expansion valve 9 is increased based on the change rate of the operating capacity, and the process returns. Specifically, in step S13a, the valve opening degree is increased by the amount obtained by multiplying the current valve opening degree of the oil cooling electronic expansion valve 9 by the change rate of the operating capacity.

As the rate of change of the operating capacity used in step S13a, "F1/F", which is the ratio between the operating capacity F before the start of increasing the operating capacity and the target operating capacity F1 that is the target for increasing the operating capacity, is used. The rate of change of the operating capacity used in step S13a is "F2/F", which is the ratio between the operating capacity F before the operating capacity starts to increase and the current capacity F2 at the time when the operating capacity starts to decrease due to the execution of the protection control. may be used.

The rate of change of the operating capacity used in step S13a is not obtained by multiplying the current valve opening degree of the oil cooling electronic expansion valve 9 without changing the rate of change of the operating capacity as described above, but by increasing the operating capacity ( For example, when F1/F is used, the correction ratio obtained by multiplying F1/F-1) by a constant correction coefficient α stored in the memory 72 is used to determine the valve opening degree of the oil cooling electronic expansion valve 9. may be calculated. That is, the current valve opening of the oil-cooling electronic expansion valve 9 is multiplied by the correction ratio and added to the current valve opening, and the valve opening is increased to the corresponding opening. For example, if the correction coefficient α is set to a numerical value less than 1, such as 0.5, it is possible to prevent the amount of increase in the valve opening degree of the oil-cooling electronic expansion valve 9 in step S13a from becoming too large. . The rate of change of the operating capacity used in step S13a may be an indefinite rate of change determined by the operating state as described above, or may be a constant rate of change set in advance.

If it is determined in step S11 that the operating capacity increase of the compressor 1 is not prohibited, it is determined in step S13b whether or not the timer T1 has reached 0 seconds. If it is determined in step S13b that the timer T1 has reached 0 second, in step S13c the timer T1 is started to count the elapsed time from the end of the protection control, and the process proceeds to step S15. On the other hand, if it is determined in step S13b that the timer T1 has not reached 0 seconds, the process proceeds to step S15.

In step S15, it is determined whether or not the valve opening degree of the oil cooling electronic expansion valve 9 is currently being suppressed in step S12 or step S13a.

If it is determined in step S15 that the valve opening degree of the oil cooling electronic expansion valve 9 is not being suppressed, the process returns. On the other hand, if it is determined in step S15 that the valve opening degree of the oil cooling electronic expansion valve 9 is being suppressed, then in step S15b the measured value of the timer T1 becomes equal to or longer than the reference time such as several seconds. determine whether or not there is

If it is determined in step S15b that the measured value of the timer T1 is equal to or greater than the reference time, in step S16, the state in which the degree of opening of the oil cooling electronic expansion valve 9 is suppressed is ended, and the process returns. On the other hand, if it is determined in step S15b that the measured value of the timer T1 has not exceeded the reference time, then in step S15c the degree of superheat of the oil cooler 7 is set to the degree of superheat of the liquid back-up judgment threshold stored in advance in the memory 72. Determine whether it is less than The degree of superheat of the oil cooler 7 is the ratio between the outlet gas temperature detected by the outlet gas temperature sensor 19 provided on the outlet side of the oil cooler 7 and the intermediate pressure equivalent saturation temperature detected by the intermediate pressure sensor 13. Calculated by difference.

If it is determined in step S15c that the degree of superheat of the oil cooler 7 is not less than the liquid back determination threshold value, the process returns. On the other hand, if it is determined in step S15c that the degree of superheat of the oil cooler 7 is less than the degree of superheat of the liquid backflow determination threshold, it means that the refrigerant that has left the oil cooler 7 tends to be liquid backflow, so step S16. , the state in which the degree of valve opening of the oil cooling electronic expansion valve 9 is suppressed is ended, and the process returns. As a result, when the refrigerant that has left the oil cooler 7 tends to liquid-back, the control for suppressing the liquid-back can be executed with priority over the control for suppressing the decrease in the degree of opening of the valve.

In the valve opening reduction suppression control in the second embodiment as described above, the valve opening of the oil cooling electronic expansion valve 9 is increased based on the rate of change in the operating capacity of the compressor 1. The amount of change in valve opening can be adjusted according to the amount of change in operating capacity. That is, when the amount of change in the operating capacity of the compressor 1 is large, the current degree of opening of the oil cooling electronic expansion valve 9 can be greatly increased, so that the protection control can be easily terminated, and the compression The operating capacity of the machine 1 can be increased as stably as possible.

In the valve-opening-degree reduction suppression control in the second embodiment, in step S15c, the valve-opening degree of the oil-cooling electronic expansion valve 9 is suppressed when the refrigerant exiting the oil cooler 7 tends to flow back. Since the state is ended, the liquid backflow tendency can be improved without being restricted by the valve opening reduction suppression control in the situation where the liquid backflow tendency should be improved.

Embodiment 3.
Embodiment 3 describes an example in which the above-described protection control and valve opening reduction suppression control are applied to a brine chiller device that constitutes a refrigeration cycle device. FIG. 8 is an overall configuration diagram of the brine chiller device 101. As shown in FIG. In FIG. 8, devices similar to those in FIG. 1 are given the same reference numerals. In FIG. 8, illustration of a pump for pumping cooling water and brine and an inverter for driving the pump is omitted.

A brine chiller device 101 shown in FIG. 8 is a water-cooled cooling system equipped with a two-stage constant-speed compressor 31 . The brine chiller device 101 includes a constant speed compressor 31, an oil separator 2, a water-cooled condenser 32, an intercooler 4, a main liquid expansion valve 5, an electronic expansion valve for intermediate cooling 8, an electronic expansion valve for motor cooling 10, a suction Temperature sensor 11, suction pressure sensor 12, intermediate pressure sensor 13, discharge pressure sensor 14, discharge temperature sensor 15, outlet liquid temperature sensor 16, outlet gas temperature sensor 17, supply oil temperature sensor 18, main refrigerant pipe 20, refrigerant for intercooler Pipe 21, motor cooler refrigerant pipe 23, oil supply pipe 24, evaporating pressure sensor 27, outlet gas temperature sensor 28, cooling water pipe 33, brine cooler 34, brine pipe 35, inlet temperature sensor 36, outlet temperature sensor 37, water cooling It includes a type oil cooler 38 and a cooling water flow control valve 39 for oil cooling.

In the brine chiller device 101, the constant speed compressor 31, the water-cooled condenser 32, the main liquid expansion valve 5, and the brine cooler 34 constitute a basic refrigeration cycle. Refrigerant is circulated mainly in the main refrigerant pipe 20, which is a route passing through the constant speed compressor 31, the oil separator 2, the water-cooled condenser 32, the intercooler 4, the main liquid expansion valve 5, and the brine cooler 34. . In addition to these paths, in the brine chiller device 101 , the refrigerant is also circulated through the intercooler refrigerant pipe 21 and the motor cooler refrigerant pipe 23 branched from the main refrigerant pipe 20 .

The brine cooler 34 is a heat exchanger that exchanges heat between the two-phase refrigerant, which has been decompressed by the main liquid expansion valve 5 and has a low pressure and low temperature, and the brine (antifreeze liquid) flowing through the brine pipe 35 . The brine in the brine pipe 35 is pumped by a brine pump (not shown). An inlet temperature sensor 36 detects the temperature of the inlet of the brine in the brine cooler 34 . An outlet temperature sensor 37 detects the outlet temperature of the brine in the brine cooler 34 .

The constant speed compressor 31 is not driven by an inverter like the compressor 1 of Embodiments 1 and 2, but is driven by a commercial power source with frequencies of 50 Hz and 60 Hz, for example. The constant speed compressor 31 has a mechanical displacement control mechanism (not shown) used for controlling the discharge amount. The mechanical capacity control mechanism changes the operating capacity of the constant speed compressor 31 by partially bypassing the compressed gas of the constant speed compressor 31 to the suction side inside the constant speed compressor 31 to reduce the discharge amount. possible configuration.

The capacity control of the mechanical capacity control mechanism performs proportional control based on, for example, the difference between the brine outlet temperature detected by the outlet temperature sensor 37 and the target brine outlet temperature pre-stored in the memory 82 of the controller 80. It is done by In the displacement control of the mechanical displacement control mechanism, when the brine outlet temperature is higher than the target brine outlet temperature, the displacement of the mechanical displacement control mechanism is increased to increase the compressor discharge amount. In Embodiments 1 and 2 described above, an example was shown in which the controller changes the operating capacity of compressor 1 by changing the rotation speed of compressor 1 using an inverter. The controller changes the operating capacity of the constant speed compressor 31 by changing the discharge amount of the constant speed compressor 31 using a mechanical capacity control valve.

The mechanical capacity control mechanism is also used for protection control. For example, as shown in FIG. 3, when the load exceeds the load upper limit value such as the first load upper limit value and the second load upper limit value, the mechanical capacity control mechanism is used to reduce the operating capacity. As a result, control for reducing the load on the constant speed compressor 31 is executed.

The water-cooled condenser 32 is a heat exchanger that condenses the refrigerant gas by exchanging heat between the cooling water flowing through the cooling water pipe 33 and the high-temperature and high-pressure refrigerant gas discharged from the constant speed compressor 31 . The amount of cooling water supplied through the cooling water pipe 33 is controlled by the local system and is generally constant. The cooling water that has been heat-exchanged in the water-cooled condenser 32 and raised in temperature exits the water-cooled condenser 32 and is returned to the water-cooled condenser 32 after radiating heat in a cooling tower in a field facility (not shown). The cooling water in the cooling water pipe 33 is pressure-fed in the cooling water pipe 33 by a cooling water pump (not shown) in on-site equipment, and circulates between the water-cooled condenser 32 and the cooling tower.

The water-cooled oil cooler 38 is a heat exchanger that cools the refrigerating machine oil by exchanging heat between the refrigerating machine oil separated from the refrigerant by the oil separator 2 and flowing in and the cooling water flowing through the cooling water pipe 33 . For the water-cooled condenser 32, the brine cooler 34, and the water-cooled oil cooler 38, shell-and-tube heat exchangers or plate heat exchangers are used. The water-cooled condenser 32 is controlled to adjust the temperature of the refrigerating machine oil supplied to the constant speed compressor 31 by adjusting the amount of cooling water supplied through the oil cooling cooling water flow rate adjustment valve 39 . Alternatively, the temperature of the refrigerating machine oil supplied to the constant speed compressor 31 may be adjusted by adjusting the temperature of the cooling water supplied through the oil cooling cooling water flow rate adjustment valve 39 . .

The brine chiller device 101 further includes a control device (control device 80 shown in FIG. 9) that controls on-site facilities such as the equipment that constitutes the brine chiller device 101 and the cooling water pump.

The control device 80 in the brine chiller device 101 shown in FIG. 8 has a function of transmitting an operation command and a stop command to the cooling water pump and an operation command and a stop command to the brine pump. As a configuration for transmitting an operation command and a stop command to on-site equipment including a cooling water pump and a brine pump, a configuration for outputting commands using a voltage contact or a non-voltage contact is common. The control device 80 can adjust the flow rate of the cooling water by transmitting an analog signal (DC 4-20 mA) as a control signal to the cooling water flow rate adjustment valve 39 for oil cooling.

For example, if the target value of the oil supply temperature from the water-cooled oil cooler 38 is 50° C., for example, and the oil supply temperature detected by the oil supply temperature sensor 18 is higher than 50° C., the control device 80 controls the oil cooling water flow rate adjustment valve By outputting a control signal to increase the opening of the valve 39 and increasing the amount of cooling water supplied to the water-cooled oil cooler 38, the refrigerating machine oil supplied from the water-cooled oil cooler 38 to the constant speed compressor 31 is supplied. Control to lower the temperature.

On the other hand, if the target value of the oil supply temperature from the water-cooled oil cooler 38 is, for example, 50° C. and the oil supply temperature detected by the oil supply temperature sensor 18 is lower than 50° C., the controller 80 controls the oil cooling water flow rate adjustment valve By outputting a control signal to decrease the opening degree of the valve 39 and decreasing the amount of cooling water supplied to the water-cooled oil cooler 38, the refrigerating machine oil supplied from the water-cooled oil cooler 38 to the constant speed compressor 31 is supplied. Control to raise the temperature. The control device 80 controls the supply temperature of the refrigerating machine oil supplied to the constant speed compressor 31 to a target value by executing regular control in which such control is performed at regular time intervals.

[Control configuration example]
Next, a control configuration example of the brine chiller device 101 will be described. FIG. 9 is a block diagram showing a control configuration example of the brine chiller device 101. As shown in FIG.

The control device 80 includes a CPU 81, a memory 82 (ROM and RAM), an input/output buffer (not shown) for inputting/outputting various signals, and the like. The CPU 81 expands a program stored in the ROM into the RAM or the like and executes it. The program stored in the ROM is a program in which processing procedures of the control device 80 are described. The control device 80 controls each device in the brine chiller device 101 according to these programs. This control is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.

In the control device 80, a suction temperature sensor 11, a suction pressure sensor 12, an intermediate pressure sensor 13, a discharge pressure sensor 14, a discharge temperature sensor 15, an outlet liquid temperature sensor 16, an outlet gas temperature sensor 17, a feed oil temperature sensor 18, an evaporating pressure Detection signals from the sensor 27, the outlet gas temperature sensor 28, the inlet temperature sensor 36, and the outlet temperature sensor 37 are input.

In the control device 80, the constant speed compressor 31, the oil separator 2, the main liquid expansion valve 5, the intermediate cooling electronic expansion valve 8, the oil cooling cooling water flow rate adjustment valve 39, and the motor cooling electronic expansion valve 10 output a control signal to each of The control device 80 also outputs a control signal to the on-site equipment 90 including the aforementioned cooling water pump and brine pump. The oil cooling cooling water flow rate adjustment valve 39 is configured by an electronic adjustment valve.

[Control contents of protection control and valve opening reduction suppression control]
In Embodiment 3, the control contents of the protection control and the valve opening reduction suppression control executed by the CPU 81 of the control device 80 will be described.

Regarding the protection control in Embodiment 3, the same control as the protection control performed in Embodiments 1 and 2 is performed.

FIG. 10 is a flowchart showing valve opening reduction suppression control in the third embodiment. Valve-opening degree reduction suppression control is executed in conjunction with execution of protection control. In the valve opening reduction suppression control, the CPU 81 executes the following processes.

In step S21, it is determined whether or not the operating capacity of the constant speed compressor 31 is currently being suppressed by protection control. Specifically, in step S21, there is a state in which an increase in the operating capacity of the constant speed compressor 31 is prohibited by the second protection control described above, and a state in which the operating capacity of the constant speed compressor 31 is decreased by the first protection control described above. It is determined whether or not the operating capacity of the constant speed compressor 31 is being suppressed by protection control by determining whether or not at least one of the above applies.

If it is determined in step S21 that the operating capacity of the constant-speed compressor 31 is being suppressed by protection control, then in step S22, the control target value for the temperature of the oil-cooling cooling water flow rate adjustment valve 39 is set to the first target value. It is determined whether or not. The control target value of the temperature in this case is the control target value of the refueling temperature detected by the refueling temperature sensor 18 . The first target value determined in step S22 is the temperature control target value during normal control before protection control is executed.

If it is determined in step S22 that the temperature control target value is not the first target value, the process returns. On the other hand, if it is determined in step S22 that the temperature control target value is the first target value, then in step S23 the temperature control target value of the oil-cooling cooling water flow rate adjustment valve 39 is set lower than the first target value. Switch to temperature control target value and return. Specifically, in step S23, the control target value may be switched by decreasing the temperature of the first target value by a constant reduction temperature (for example, 5° C.) stored in the memory 82. It may be switched to the second control target value (for example, 45° C.) stored in memory 82 .

If it is determined in step S21 that the operating capacity of the constant-speed compressor 31 is not being suppressed by protection control, in step S24, the control target value of the temperature of the oil-cooling cooling water flow rate adjustment valve 39 is changed to the first target value. , it is determined whether or not it is in the state of being switched. Specifically, in step S24, it is determined whether or not the temperature control target value is being switched in step S23.

If it is determined in step S24 that the control target value is not being switched from the first target value, the process returns. On the other hand, if it is determined in step S24 that the control target value is being switched from the first target value, in step S25 it is determined whether the operating capacity of the constant speed compressor 31 is being reduced by protection control. determine whether

If it is determined in step S25 that the operating capacity of the constant speed compressor 31 is not decreasing, the process returns. On the other hand, if it is determined in step S25 that the operating capacity of the constant speed compressor 31 is being reduced, in step S26 it is determined whether or not the reduction in the operating capacity of the constant speed compressor 31 by protection control has been completed. judge.

If it is determined in step S26 that the reduction in the operating capacity of the constant speed compressor 31 has not been completed, the process returns. On the other hand, if it is determined in step S26 that the reduction in the operating capacity of the constant speed compressor 31 has been completed, then in step S27 the switching of the control target value for the temperature of the cooling water flow rate adjustment valve 39 for oil cooling in step S23 ends. Then, the temperature control target value is returned to the original first target value, and the process returns.

In the valve opening reduction suppression control in the third embodiment as described above, when the operating capacity of the constant speed compressor 31 is being suppressed by the protection control, the oil cooling water flow rate adjustment valve 39 is turned on in step S23. After lowering the temperature control target value, in steps S26 and S27, after the reduction of the operating capacity of the constant-speed compressor 31 by protection control is completed, the temperature control target value of the oil-cooling cooling water flow rate adjustment valve 39 is lowered. Control to return to the original control target value is executed. By executing such control, the control target value of the oil-cooling cooling water flow rate adjustment valve 39 is kept lowered even during the period when the operating capacity of the constant speed compressor 31 needs to be increased. Therefore, in the operation of the constant speed compressor 31, it is possible to avoid the occurrence of unstable operation such as repeating the activation and release of protection control, and the occurrence of insufficient operability of the constant speed compressor 31. can do.

[Modifications of Embodiments 1 to 3]
In Embodiments 1 to 3, the discharge temperature of the compressor 1 and the constant speed compressor 31 is taken as an example of the overload load amount that is the condition for executing the protection control and the valve opening reduction suppression control. , if the overload state can be determined by the load amount indicated by another physical quantity, the other physical quantity may be used to detect the overload state and perform protection control and valve opening reduction suppression control. good. Other physical quantities include, for example, the discharge pressure of the compressor (compressor 1, constant speed compressor 31), the condensation pressure of the condenser (air-cooled condenser 3, water-cooled condenser 32), the condensation temperature of the condenser, the compressor Operating current of (compressor 1, constant speed compressor 31), power consumption of compressor (compressor 1, constant speed compressor 31), and suction superheat of compressor (compressor 1, constant speed compressor 31) degree. When the distance from the compressor to the condenser is short, the condensing pressure of the condenser (air-cooled condenser 3, water-cooled condenser 32) becomes a value close to the discharge pressure. These physical quantities are physical quantities whose value increases as the operating capacity of the compressor (compressor 1, constant speed compressor 31) increases. The same logic as the logic may be used to execute the protection control and the valve opening reduction suppression control in the first to third embodiments. The parameter that can determine the overload state from the load amount indicated by the physical quantity may be, for example, one parameter such as the discharge temperature of the compressor (compressor 1, constant speed compressor 31). A plurality of parameters may be used in combination. That is, at least one parameter may be used as the parameter that can determine the overload state from the amount of load indicated by the physical quantity.

In this way, physical quantities other than the discharge temperature of the compressors (compressor 1, constant speed compressor 31) can be used to determine the overload state of the compressors (compressor 1, constant speed compressor 31). Therefore, a sensor other than the discharge temperature sensor 15 may be used for detection. Therefore, the refrigeration supplied to the compressor (compressor 1, constant speed compressor 31) as a physical quantity detected for controlling the temperature adjustment device (oil cooling electronic expansion valve 9, oil cooling cooling water flow rate adjustment valve 39) The physical quantity that changes with the temperature of machine oil and the physical quantity that is detected to determine the load state of the compressors (compressor 1, constant speed compressor 31) are the same physical quantity that can be detected by one sensor (discharge temperature sensor 15). may be Further, as described above, when a sensor other than the discharge temperature sensor 15 detects a physical quantity for determining the overload state of the compressor, the physical quantity that changes depending on the temperature of the refrigerating machine oil supplied to the compressor and the load on the compressor Since the physical quantity detected for determining the state is different, the physical quantity that changes with the temperature of the refrigerating machine oil supplied to the compressor and the physical quantity that is detected for determining the load state of the compressor are detected by a plurality of different sensors. may be detected. In this way, the physical quantity detected for controlling the temperature adjustment device (oil cooling electronic expansion valve 9, oil cooling cooling water flow rate adjustment valve 39) and the compressor (compressor 1, constant speed compressor 31) The physical quantity used to determine the load state may be detected by one sensor, may be detected by a plurality of sensors, or may be detected by at least one sensor. .

Further, in Embodiments 1 and 2, the discharge temperature Although an example using the discharge temperature detected by the sensor 15 has been shown, the physical quantity detected when controlling the oil cooling electronic expansion valve 9 is not limited to this, and may include the refueling temperature detected by the refueling temperature sensor 18, That is, the temperature of the refrigerating machine oil supplied to the compressor 1 may be used. In this manner, the control device 70 may control the oil cooling electronic expansion valve 9 based on the supply oil temperature detected by the supply oil temperature sensor 18 .

In the third embodiment, the physical quantity detected when controlling the oil cooling water flow rate adjustment valve 39 based on the detected value of the physical quantity that changes with the temperature of the refrigerating machine oil supplied to the constant speed compressor 31 is: Although an example using the temperature of the refrigerating machine oil supplied to the compressor 1, which is detected by the oil temperature sensor 18, is shown, the present invention is not limited to this, and the oil cooling water flow control valve 39 is controlled. The physical quantity to be detected may be the ejection temperature detected by the ejection temperature sensor 15 . In this manner, the control device 80 may control the oil cooling coolant flow rate adjustment valve 39 based on the discharge temperature detected by the discharge temperature sensor 15 .

In addition, in the refrigeration cycle apparatus, as for the physical quantity that can indicate the load quantity, instead of using one physical quantity to control the load quantity, for example, the compressor (compressor 1, constant speed compressor 31) discharge temperature, the discharge pressure of the compressor (compressor 1, constant speed compressor 31), and the operating current of the compressor (compressor 1, constant speed compressor 31). An overload amount upper limit value may be set for each physical quantity, and protection control may be executed based on the detection result of each detection means. For example, if protection control is executed due to an increase in operating current during operation, not only the operating current but also the discharge temperature and discharge pressure will simultaneously decrease in accordance with the decrease in operating capacity. In such a case, the capacity of at least one of the electronic expansion valve and the flow control valve may decrease. good.

In addition, it is possible to apply the above-described protection control and valve opening reduction suppression control to the main liquid expansion valve 5, for example. For example, the main liquid expansion valve 5 is regularly controlled based on the degree of superheat at the outlet of the evaporator 6 . In the compressor 1, if the degree of suction superheat becomes too large, the discharge temperature rises and the compressor 1 may be seized. Therefore, when the degree of suction superheat exceeds the upper limit value, protective control may be executed to reduce the operating capacity. In this case, as a result of the decrease in the operating capacity due to the protection control, the degree of superheat at the outlet of the evaporator also decreases, so the degree of opening of the main liquid expansion valve 5 may decrease. This is the same as the relation between the protection control and the regular control of the oil cooling electronic expansion valve 9 in the first embodiment in which the protection control and the valve opening reduction suppression control are executed based on the discharge temperature of the compressor 1. , and it is possible to apply the above-described protection control and valve opening reduction suppression control to the main liquid expansion valve 5 as well.

[Summary of Embodiment]
The embodiments described above will be described with reference to the drawings again.

The present disclosure relates to a refrigeration cycle device 100. The refrigerating cycle device 100 includes a compressor 1 that compresses refrigerant, an oil separator 2 that separates the refrigerant discharged from the compressor 1 from refrigerating machine oil, and a refrigerating machine oil separated by the oil separator 2. An oil supply pipe 24 that supplies machine oil to the compressor 1, an oil cooler 7 that cools the refrigerating machine oil that is supplied to the compressor 1, and an oil cooling medium path that supplies refrigerant as a cooling medium to the oil cooler 7. a device refrigerant pipe 22, an oil cooling electronic expansion valve 9 as a temperature adjusting device for adjusting the temperature of the refrigerating machine oil supplied to the compressor 1, at least one sensor such as a discharge temperature sensor 15, and a control device 70 , the control device 70 controls the oil cooling electronic expansion valve 9 based on the detected value of the physical quantity that changes with the temperature of the refrigerating machine oil supplied to the compressor 1 detected by the discharge temperature sensor 15, and the discharge temperature The load state of the compressor 1 is determined based on the detected value of the physical quantity used for determining the load state of the compressor 1 detected by the sensor 15, and the load state of the compressor 1 is determined to be the overload state. In this case, protection control, which is first control for suppressing an increase in the operating capacity of the compressor 1, is performed, and second control, which is a second control for suppressing a decrease in the adjustment capacity of the oil cooling electronic expansion valve 9, that is, the valve opening degree, is performed. Controls the degree of opening reduction.

With such a configuration, the protection control that suppresses an increase in the operating capacity of the compressor 1 and the valve opening reduction suppression control that suppresses a decrease in the valve opening of the oil cooling electronic expansion valve 9 are related. is executed. As a result, when the compressor 1 is overloaded, the protection control for suppressing the increase in the operating capacity of the compressor 1 is prevented from being hindered by the control of the valve opening degree of the oil cooling electronic expansion valve 9. Therefore, it is possible to prevent the protection control from being repeatedly executed and the operating capacity of the compressor 1 from becoming insufficient due to the protection control, so that the operating state of the refrigeration cycle apparatus 100 can be stabilized.

Preferably, the oil cooler 7 is supplied with a refrigerant as a cooling medium, and the oil cooling electronic expansion valve 9 as a temperature control device adjusts the supply amount of the refrigerant supplied to the oil cooler 7 to control the compression. The temperature of the refrigerating machine oil supplied to the machine 1 is adjusted.

Preferably, a water-cooled oil cooler 38 as an oil cooler is supplied with cooling water as a cooling medium, and an oil cooling cooling water flow rate adjustment valve 39 as a temperature adjustment device is supplied to the water-cooled oil cooler 38. The temperature of the refrigerating machine oil supplied to the constant speed compressor 31, which is a compressor, is adjusted by adjusting the supply amount or temperature of the cooling water.

Preferably, the control device 70 is in an overload state based on at least one of the discharge temperature, the discharge pressure, the condensing temperature, the operating current, the power consumption, and the degree of suction superheat in the compressor 1. Determine whether or not

Preferably, as a sensor that detects a physical quantity for controlling the oil cooling electronic expansion valve 9 or the oil cooling cooling water flow rate adjustment valve 39, the compressor 1, such as the feed oil temperature sensor 18 and the discharge temperature sensor 15, Alternatively, at least one of the temperature of the refrigerating machine oil supplied to the constant speed compressor 31 and the temperature of the gas discharged from the compressor 1 may be detected.

Preferably, when executing the protection control as the first control, the control device 70 reduces the valve opening degree of the oil cooling electronic expansion valve 9 as the temperature adjustment device in the valve opening degree decrease suppression control as the second control. to increase

Preferably, the control device 70, in the valve-opening-degree reduction suppression control, which is the second control, increases the valve-opening degree of the oil-cooling electronic expansion valve 9 as the temperature adjusting device by a constant increase rate to the current valve-opening degree. The valve opening degree obtained by multiplying is increased (step S13a).

Preferably, the control device 70 sets the valve opening degree of the oil cooling electronic expansion valve 9 as the temperature adjustment device to the current valve opening degree in the valve opening degree decrease suppression control, which is the second control. The adjustment capacity is increased by adding degrees (step S14).

Preferably, the control device 80 sets the target value of the temperature of the refrigerating machine oil to be adjusted by the oil-cooling cooling water flow rate adjustment valve 39 as the temperature adjustment device in the valve opening reduction suppression control, which is the second control, to the first target value. value to a second target value lower than the first target value (step S23).

Preferably, the control device 70 controls the compressor 1 in the protection control, which is the first control, when the overload state is determined during the operation for increasing the operating capacity of the compressor 1 for adjusting the cooling or heating capacity. In addition, in the valve opening reduction suppression control, which is the second control, the valve opening of the oil cooling electronic expansion valve 9 as a temperature adjustment device is set to the current valve opening, and the compressor 1 The valve opening degree is increased by multiplying the rate of increase of the operating capacity during the operation in which the operating capacity is to be increased by a fixed rate correction (step S13a).

Preferably, when the operating capacity of the compressor 1 is reduced in the protection control, which is the first control, in order to adjust the cooling or heating capacity, the control device 70 reduces the temperature in the valve opening reduction suppression control, which is the second control. As an adjustment device, the current valve opening of the oil cooling electronic expansion valve 9 is adjusted to the current valve opening, and the operating capacity of the compressor 1 is increased during operation, and a constant correction is made to the increase rate of the operating capacity. The valve opening degree obtained by multiplying the added ratio is increased to the valve opening degree (step S13a).

Preferably, the control device 70 performs the protection control when the end condition of the valve opening reduction suppression control, which is the second control, is satisfied in association with the end condition of the protection control, which is the first control. or when the timer T1 in step S13c has elapsed), the valve opening reduction suppression control is terminated (step S16).

Preferably, the control device 70 changes the load state of the compressor 1 when the load amount based on the discharge temperature detected by a sensor such as the discharge temperature sensor 15 reaches the second load amount upper limit value (85° C.). Detection of the discharge temperature detected by a sensor such as the discharge temperature sensor 15 in a state in which the overload state is determined and the protection control, which is the first control, and the valve opening reduction suppression control, which is the second control, are being executed. When the load amount based on the value becomes less than the third load amount upper limit value (80° C.) which is less than the second load amount upper limit value (85° C.), the valve opening reduction suppression control, which is the second control, is ended. (S15a, S16).

Preferably, the control device 80 responds to the completion of the reduction of the operating capacity of the constant speed compressor 31 during the operation of reducing the operating capacity of the constant speed compressor 31 for cooling or heating capacity adjustment. , the valve opening reduction suppression control is ended (step S27).

Preferably, the oil cooler 7 is supplied with a refrigerant as a cooling medium, and the controller 70 controls the outlet gas temperature detected by the outlet gas temperature sensor 19 provided on the outlet side of the oil cooler 7 and the intermediate pressure When the degree of superheat of the refrigerant on the outlet side of the oil cooler 7 obtained by the difference from the equivalent saturation temperature of the intermediate pressure detected by the sensor 13 becomes less than the liquid backflow determination threshold value for determining that liquid backflow occurs, The valve opening reduction suppression control, which is the second control, ends (steps S15c and S16).

The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of the claims rather than the description of the above-described embodiments, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

100, 101 refrigeration cycle device, 1 compressor, 2 oil separator, 24 oil supply path, 7 oil cooler, 22 cooling medium path, 9 oil cooling electronic expansion valve, 15 discharge temperature sensor, 70, 80 control device, 31 Constant speed compressor, 38 Water-cooled oil cooler, 33 Cooling water piping.

Claims (15)

1. a compressor that compresses a refrigerant;
   an oil separator for separating refrigerant discharged from the compressor and refrigerating machine oil;
   an oil supply path for supplying the refrigerating machine oil separated by the oil separator to the compressor;
   an oil cooler that cools refrigerating machine oil supplied to the compressor;
   a cooling medium path that supplies a cooling medium to the oil cooler;
   a temperature adjusting device that adjusts the temperature of refrigerating machine oil supplied to the compressor;
   at least one sensor;
   a control device;
   The control device is
   controlling the temperature adjustment device based on the detected value of the physical quantity that changes with the temperature of the refrigerating machine oil supplied to the compressor detected by the sensor;
   Determining the load state of the compressor based on the detected value of the physical quantity used for determining the load state of the compressor, which is detected by the sensor;
   When the load state of the compressor is determined to be an overload state, first control is performed to suppress an increase in the operating capacity of the compressor, and second control is performed to suppress a decrease in the adjustment capacity of the temperature adjustment device. refrigeration cycle equipment.
2. A refrigerant is supplied as a cooling medium to the oil cooler,
   The refrigeration cycle apparatus according to claim 1, wherein the temperature adjustment device adjusts the temperature of refrigerating machine oil supplied to the compressor by adjusting the amount of refrigerant supplied to the oil cooler.
3. Cooling water is supplied as a cooling medium to the oil cooler,
   2. The refrigeration cycle apparatus according to claim 1, wherein said temperature adjustment device adjusts the temperature of refrigerating machine oil supplied to said compressor by adjusting the supply amount or temperature of cooling water supplied to said oil cooler.
4. The control device determines whether or not the compressor is in the overload state based on at least one of discharge temperature, discharge pressure, condensing temperature, operating current, power consumption, and suction superheat degree. The refrigeration cycle apparatus according to any one of claims 1 to 3, which determines whether the
5. 2. The sensor detects at least one of a temperature of gas discharged from the compressor and a temperature of refrigerating machine oil supplied to the compressor as a physical quantity detected for controlling the temperature adjustment device. 5. The refrigeration cycle device according to any one of 1 to 4.
6. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the control device increases the adjustment capacity of the temperature adjustment device in the second control when executing the first control.
7. 7. The refrigeration cycle apparatus according to claim 6, wherein in the second control, the control device increases the adjustment capacity of the temperature adjustment device to an adjustment capacity obtained by multiplying the current adjustment capacity by a constant rate.
8. The refrigeration cycle apparatus according to claim 6, wherein in the second control, the control device increases the adjustment capacity of the temperature adjustment device to an adjustment capacity obtained by adding a certain adjustment capacity to the current adjustment capacity.
9. The control device, in the second control, lowers the target value of the temperature of the refrigerating machine oil to be adjusted by the temperature adjustment device from a first target value to a second target value lower than the first target value. 7. The refrigeration cycle device according to 6.
10. The control device reduces the operating capacity of the compressor in the first control when the overload state is determined during an operation in which the operating capacity of the compressor is increased for adjustment of cooling or heating capacity. In addition, in the second control, the adjustment capacity of the temperature adjustment device is increased to an adjustment capacity obtained by multiplying the current adjustment capacity by the rate of increase in the operating capacity during operation in which the operating capacity of the compressor is increased. The refrigeration cycle device according to claim 6, wherein
11. The control device reduces the operating capacity of the compressor in the first control when the overload state is determined during an operation in which the operating capacity of the compressor is increased for adjustment of cooling or heating capacity. and, in the second control, the adjustment capacity of the temperature adjustment device is set to the current adjustment capacity plus a fixed rate correction to the increase rate of the operating capacity during the operation in which the operating capacity of the compressor is increased. 7. The refrigeration cycle apparatus according to claim 6, wherein the adjustment capacity obtained by multiplying is increased to the adjustment capacity.
12. Claims 1 to 11, wherein the control device terminates the second control when a termination condition for the second control that is satisfied in relation to satisfaction of a termination condition for the first control is satisfied. Refrigeration cycle apparatus according to any one of the.
13. The control device is
    determining that the load state of the compressor is the overload state when the detected value of the physical quantity used for determining the load state of the compressor detected by the sensor becomes a first determination value;
    In a state in which the first control and the second control are being executed, the detected value of the physical quantity used for determining the load state of the compressor detected by the sensor is less than the first determination value. 12. The refrigeration cycle apparatus according to any one of claims 1 to 11, wherein the second control is terminated when the second judgment value is reached.
14. The control device terminates the second control in response to completion of reduction of the operating capacity of the compressor during operation for reducing the operating capacity of the compressor for adjustment of cooling or heating capacity. 14. The refrigeration cycle apparatus according to any one of claims 1 to 13.
15. A refrigerant is supplied as a cooling medium to the oil cooler,
    The control device terminates the second control when the degree of superheat of the refrigerant on the outlet side of the oil cooler obtained based on the detection result of the sensor is less than a threshold for determining that liquid backflow occurs. The refrigeration cycle apparatus according to any one of claims 1, 2, and 4 to 14.

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