JP2018021696A - Chiller and control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chiller capable of improving the tracking performance of the output of a refrigerator with respect to the cooling load while reducing the consumption power.SOLUTION: A chiller 100 comprises: a refrigerator 10; cooling equipment pieces 1 to 6 cooled by the refrigerator 10; and a control part 300 configured to obtain the states of the refrigerator 10 and the cooling equipment pieces 1 to 6, obtain the cooling load and the cooling power excess or deficiency based on the obtained states of the refrigerator 10 and the cooling equipment pieces 1 to 6, and determine the control target value of the output of the refrigerator 10 based on the obtained excess or deficiency. The control part 300 is configured to when the cooling load rapidly changes, by adding the correction amount to the control target value, control the output of the refrigerator 10 based on the control target value and the correction amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling device and a control device, and more particularly to a cooling device and a control device that control the cooling capacity of a refrigerator based on a cooling load of a cooling device.

  Conventionally, a cooling device that controls the cooling capacity of a refrigerator connected to a cooling device based on the cooling load of the cooling device is known (see, for example, Patent Document 1).

  In the above Patent Document 1, in a cooling device including one or more cooling devices and a refrigerator commonly connected to the one or more cooling devices, the cooling of the refrigerator with respect to the cooling load of the entire cooling device A control unit for determining whether the capacity is excessive or insufficient is provided. Each cooling device is provided with an evaporator, and the cooling device is cooled by flowing a refrigerant into the evaporator. Each cooling device is provided with a solenoid valve, and is configured to start and stop the flow of the refrigerant to the evaporator by opening and closing operations of the solenoid valve. If there is a cooling device in which the temperature in the cabinet is higher than the target temperature range, the control unit opens the electromagnetic valve connected to the cooling device, and flows the refrigerant to cool it. On the other hand, if there is a cooling device whose inside temperature is lower than the target temperature range, the solenoid valve connected to the cooling device is closed to stop the flow of the refrigerant and stop the cooling. Here, the control unit determines whether the output of the refrigerator is excessive or insufficient based on the state of the refrigerator and the cooling device. If it is excessive, the output is decreased, and if it is insufficient, the output is increased.

  Further, in the cooling device of Patent Document 1, on the assumption of a normal state where the inflow of heat from the outside is limited to some extent, the power consumption is reduced by greatly reducing the output of the refrigerator to the extent necessary for maintaining the temperature. It is thought that it is configured to.

Japanese Patent Laid-Open No. 10-318644

  Here, in the cooling device of Patent Document 1, particularly in a refrigerated / refrigerated warehouse, the cooling load is stabilized for a long time with little heat intrusion due to the opening / closing of the door of the cooling device, such as a time period excluding the arrival and shipment of goods. In this case, a sufficient cooling effect can be expected even when the output of the refrigerator is lowered in order to reduce power consumption as described above. However, when the cooling load of the refrigerator significantly changes (changes suddenly), such as when goods are received or shipped, due to the fact that the output of the refrigerator is reduced to reduce power consumption, It is considered that the followability of the output of the refrigerator with respect to the cooling load is deteriorated. Therefore, a cooling device and a control device that improve the followability of the output of the refrigerator with respect to the cooling load while reducing power consumption are desired.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to improve the followability of the output of the refrigerator with respect to the cooling load while reducing power consumption. It is to provide a cooling device and a control device capable of performing the above.

  A cooling device according to a first aspect of the present invention acquires a state of a refrigerator, a cooling device cooled by the refrigerator, the refrigerator and the cooling device, and cools based on the acquired state of the refrigerator and the cooling device. A controller that obtains the excess and deficiency of the load and the cooling capacity and determines the control target value of the output of the refrigerator based on the obtained excess and deficiency, and the controller, when there is a sudden change in the cooling load, A correction amount is added to the control target value, and the output of the refrigerator is controlled based on the control target value and the correction amount.

  In the cooling device according to the first aspect of the present invention, when there is a sudden change in the cooling load, a control unit that adds a correction amount to the control target value and controls the output of the refrigerator based on the control target value and the correction amount. Is provided. As a result, if a sudden change is detected in the cooling load, a correction amount can be added to the control target value, and the output (cooling capacity) of the refrigerator can be temporarily increased in response to the sudden change. Even when there is, the followability of the output of the refrigerator with respect to the cooling load can be improved. Also, obtain the status of the refrigerator and cooling equipment, obtain the excess and deficiency of the cooling load and cooling capacity based on the obtained condition of the refrigerator and cooling equipment, and control the output of the refrigerator based on the obtained excess and deficiency The target value is determined. As a result, the control unit lowers the operation frequency of the compressor included in the refrigerator, which is the control target value, when the cooling capacity is excessive, and operates the compressor when the cooling capacity is insufficient. Since the frequency is increased, the output of the refrigerator with respect to the cooling load can be maintained at an appropriate level in a normal state where there is no sudden change in the cooling load. In this case, power consumption can be reduced if the output of the refrigerator is reduced to an extent necessary for maintaining the temperature.

  In the cooling device according to the first aspect, preferably, the control unit detects a sudden change in the cooling load based on a change amount or a change rate of the cooling load, and performs control when the sudden change is detected. Control is performed to add a correction amount to the target value. If comprised in this way, the sudden change of a cooling load can be easily detected by determining whether the variation | change_quantity or change rate of a cooling load exceeded a certain threshold value, for example.

  In the configuration for detecting a sudden change in the cooling load based on the amount or rate of change of the cooling load, the control unit preferably has a temperature in the chamber of the cooling device after a certain time has elapsed after the start of the cooling operation of the cooling device. The rapid change of the cooling load is detected based on the temperature change amount or the temperature change rate during a certain period of time. With this configuration, the cooling load increases as the temperature in the cooling device rises. Therefore, it is easy to determine whether the temperature change amount or the temperature change rate has exceeded a certain threshold, for example. A sudden change in the cooling load can be detected.

  In this case, preferably, when the control unit controls the output of the refrigerator based on the control target value and the correction amount, when the temperature change amount or the temperature change rate in the refrigerator of the cooling device changes. The correction amount is configured to be updated to a correction amount corresponding to the temperature inside the refrigerator of the cooling device. With this configuration, the correction amount is updated when the temperature in the cooling device increases after the start of the cooling operation corresponding to the sudden change in the cooling load, and the cooling load further increases. It is possible to follow the output of the refrigerator more appropriately.

  In the cooling device according to the first aspect described above, preferably, the control unit corrects the control target value in a time zone in which there is a high possibility that there is a sudden change in the cooling load and when a sudden change in the cooling load is detected. It is comprised so that control which adds quantity may be performed. With this configuration, the follow-up performance of the output of the refrigerator can be improved in a time zone in which there is a high possibility of sudden changes in the cooling load and when a sudden change in the cooling load is detected. Therefore, it is possible to prevent the increase in the output of the refrigerator from being in time for the increase in the cooling load. In addition, when the cooling load is stable and the sudden change of the cooling load hardly occurs, the correction amount is not used, so the power consumption can be reduced by keeping the output of the refrigerator low. Can do.

  The control device according to the second aspect of the present invention acquires the state of the refrigerator and the cooling device, acquires the excess and deficiency of the cooling load and the cooling capacity based on the acquired state of the refrigerator and the cooling device, and acquires the acquired excess. A control unit that determines the control target value of the output of the refrigerator based on the shortage, and the control unit adds a correction amount to the control target value and corrects the control target value and correction when there is a sudden change in the cooling load. The output of the refrigerator is controlled based on the amount.

  In the control device according to the second aspect of the present invention, when there is a sudden change in the cooling load, a control unit that adds a correction amount to the control target value and controls the output of the refrigerator based on the control target value and the correction amount. Is provided. As a result, if a sudden change is detected in the cooling load, a correction amount can be added to the control target value, and the output (cooling capacity) of the refrigerator can be temporarily increased in response to the sudden change. Even when there is, the followability of the output of the refrigerator with respect to the cooling load can be improved. Also, obtain the status of the refrigerator and cooling equipment, obtain the excess and deficiency of the cooling load and cooling capacity based on the obtained condition of the refrigerator and cooling equipment, and control the output of the refrigerator based on the obtained excess and deficiency The target value is determined. As a result, the control unit lowers the operating frequency of the compressor included in the refrigerator, which is the control target value, when the cooling capacity is excessive, and when the cooling capacity is insufficient, Since the operating frequency is increased, the output of the refrigerator with respect to the cooling load can be kept appropriate in a normal state where there is no sudden change in the cooling load. In this case, power consumption can be reduced if the output of the refrigerator is reduced to an extent necessary for maintaining the temperature.

  According to the present invention, as described above, the followability of the output of the refrigerator with respect to the cooling load can be improved while reducing power consumption.

It is the block diagram which showed the whole structure of the cooling device by one Embodiment of this invention. It is the block diagram which showed the structure of the control part and control apparatus of the cooling device by one Embodiment of this invention. It is the figure which showed an example of the temperature change graph in the store | warehouse | chamber of the cooling device by one Embodiment of this invention, and the mode of control. It is the figure which showed an example of the schedule by one Embodiment of this invention. It is the figure which showed an example of the control parameter by one Embodiment of this invention. It is a flowchart for demonstrating the load variation detection and correction process of the control part by one Embodiment of this invention, and a control apparatus.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

  First, with reference to FIGS. 1-6, the structure of the cooling device 100 by this embodiment is demonstrated.

(Configuration of cooling device)
As shown in FIG. 1, the cooling device 100 according to the present embodiment includes six cooling devices 1, 2, 3, 4, 5 and 6, and 1 connected to the cooling devices 1 to 6 via a refrigerant pipe 20. And a control device 30 that controls the operation of the refrigerators 1 to 6 and the refrigerator 10.

(Structure of refrigerator)
As shown in FIG. 1, the refrigerator 10 includes a compressor 11, a condenser 12, an outside air fan 13 that cools the condenser 12, and a pressure sensor 14. As shown in FIG. 2, the compressor 11, the outside air fan 13, and the pressure sensor 14 are electrically connected to the control unit 300.

  The compressor 11 is an inverter control type in which the refrigerant discharge amount can be controlled by changing the operation frequency (the number of revolutions per second). Here, one compressor 11 is provided. The condenser 12 releases heat by condensing the high-temperature and high-pressure refrigerant with the outside air to condense. The outside air fan 13 blows outside air to the condenser 12 and promotes heat exchange of the refrigerant. The pressure sensor 14 measures the suction pressure of the compressor 11.

(Configuration of cooling equipment)
As shown in FIG. 1, the cooling devices 1, 2, 3, 4, 5 and 6 include electromagnetic valves 1a, 2a, 3a, 4a, 5a and 6a, and electronic expansion valves 1b, 2b, 3b, 4b, 5b and 6b, evaporators 1c, 2c, 3c, 4c, 5c and 6c, internal fans 1d, 2d, 3d, 4d, 5d and 6d, and temperature sensors 1e, 2e, 3e, 4e, 5e and 6e, respectively Prepare. Since the cooling devices 1 to 6 have basically the same device configuration, the cooling device 1 will be described below as a representative. For convenience of explanation, the configurations of the cooling devices 2 to 6 are also referred to as appropriate. As shown in FIG. 1, a refrigeration cycle apparatus that circulates refrigerant is configured by a cooling device 1 (2 to 6) and a refrigerator 10. Moreover, the cooling devices 1-6 are mutually connected in parallel via the refrigerant | coolant piping 20 with respect to the refrigerator 10 installed in the outdoor or indoor machine room etc. of the room in which the cooling devices 1-6 were placed. . The cooling devices 1 to 6 include, for example, a showcase, a unit cooler, a freezer / refrigerated warehouse, and the like. In the present embodiment, the number of the compressors 11 is one, but a plurality of compressors 11 may be configured. Further, the number of cooling devices 1 to 6 is not limited to six, and may be configured to be increased or decreased within a range of one or a plurality of units as necessary.

  The refrigerant flowing in the refrigerant pipe 20 is discharged from the compressor 11 in the direction of the arrow P, and after passing through the condenser 12, is divided and distributed to the evaporator 1 c, and then returned to the compressor 11. The solenoid valve 1a can only be fully opened and fully closed. When any one of the solenoid valves 1a to 6a is controlled to be closed, the refrigerant will not flow through any of the corresponding evaporators 1c to 6c, and the cooling operation of the cooling device is stopped. Since the electronic expansion valve 1b can adjust the degree of opening of the plug, it is possible to control the flow rate of the refrigerant toward the evaporator 1c. The evaporator 1c is expanded by the corresponding electronic expansion valve 1b and transferred to the refrigerant wet steam in which the low-temperature and low-pressure liquid and gas are mixed. Then cool the temperature inside. The internal fan 1d circulates cold air between the internal space of the cooling device 1 and the evaporator 1c, and promotes the evaporation of the refrigerant by the evaporator 1c. The temperature sensor 1e detects the temperature of the inside of the refrigerator 1 and the evaporator 1c. Further, as shown in FIG. 2, the electromagnetic valve 1 a, the electronic expansion valve 1 b, the internal fan 1 d, and the temperature sensor 1 e are electrically connected to the control unit 300 via a communication line 81.

  As the operation content of the cooling device 1, the control unit 300 opens the solenoid valve 1a based on the comparison between the temperature range set in the chamber and the current value of the temperature detected by the temperature sensor 1e. Controlled to the closed state. When the electromagnetic valve 1a is opened, the refrigerant from the refrigerator 10 is circulated to the evaporator 1c through the electronic expansion valve 1b. Along with the control of the opening degree of the electronic expansion valve 1b, the refrigerant flow rate to the evaporator 1c is controlled to exhibit the cooling capacity. When the internal temperature reaches the set value, the solenoid valve 1a is switched to the closed state, and the cooling operation of the evaporator 1c is stopped. And if the temperature in a store | warehouse | chamber becomes less than a preset value, the solenoid valve 1a will be switched to an open state again, and the cooling operation of the evaporator 1c will be restarted. Thereby, the temperature in the store | warehouse | chamber of the cooling device 1 is maintained in the set temperature range. The operation content is the same also about the cooling devices 2-6. Therefore, the output of the refrigerator 10 also fluctuates according to the operating state of the cooling devices 1-6 at the same time (such as the open / closed state of the solenoid valves 1a-6a). In this case, the compressor 11 is based on the difference between the suction pressure set value of the compressor 11 set corresponding to the number of operating cooling devices (the number of open states of the solenoid valves 1a to 6a) and the current suction pressure. The operation frequency is controlled. As a result, the amount of refrigerant circulating in the refrigeration cycle apparatus is adjusted.

(Configuration of control device)
As shown in FIG. 2, the control device 30 includes a control unit 300 as hardware including a CPU and a memory. The control unit 300 includes, as functional blocks as software, a cooling device communication / control unit 301, a refrigerator communication / control unit 302, an operation rate calculation unit 303, a load variation detection / correction unit 306, and a control target. A value determination unit 304 and a schedule management unit 305 are included. As shown in FIGS. 1 and 2, the refrigerator 10 and the control unit 300 are communicably connected via a communication line 80. The cooling devices 1 to 6 and the control unit 300 are communicably connected via a communication line 81.

  The cooling device communication / control unit 301 as a functional block composed of software controls the opening and closing of the electromagnetic valve 1a and the opening degree of the electronic expansion valve 1b. In addition, the cooling device communication / control unit 301 acquires the temperature information of the inside of the cooling device 1 and the temperature of the evaporator 1c from the temperature sensor 1e, and controls the ventilation output of the inside fan 1d. Further, the cooling device communication / control unit 301 sends the acquired information of the temperature of the cooling device 1 and the temperature of the evaporator 1 c to the operation rate calculation unit 303 and the load fluctuation detection / correction unit 306.

  A refrigerator communication / control unit 302 as a functional block made up of software controls the operating frequency of the compressor 11. In addition, the refrigerator communication / control unit 302 controls the air blowing output of the outside air fan 13 and acquires information on the suction pressure of the compressor 11 from the pressure sensor 14. Further, the refrigerator communication / control unit 302 sends the acquired information on the suction pressure of the compressor 11 to the control target value determination unit 304.

  The operation rate calculation unit 303 as a functional block made up of software is transmitted from the cooling devices 1 to 6 via the cooling device communication / control unit 301, and the temperature inside the cooling devices 1 to 6 or the electromagnetic valves 1 a to 1. Change or maintain the operating rate of the cooling device 100 and the inside of the cooling devices 1 to 6 within the target temperature range based on the open / close rate of the solenoid valves 1a to 6a calculated from the open / closed state of the entire 6a. Therefore, the cooling load that is the amount of heat to be removed is calculated.

  The control target value determination unit 304 as a functional block composed of software is based on the cooling load and the state of the cooling device 1 acquired from the operation rate calculation unit 303 and the state of the refrigerator 10 obtained from the refrigerator communication / control unit 302. A control target value to be reached in order to change or maintain the temperature in the cabinet of the cooling devices 1 to 6 within the target temperature range is calculated and determined. The control target value is a target value such as the operating frequency of the compressor 11, the suction pressure of the compressor 11, or the evaporation temperature of the refrigerant in the evaporator 1 c. Then, in order to change the current state of the cooling device 1 and the refrigerator 10 toward the control target value, the operation frequency of the compressor 11, the electromagnetic valve 1 a and the electronic expansion valve 1 b are transmitted via the communication lines 81 and 80. The opening state of the is changed.

  The schedule management unit 305 as a functional block composed of software has a schedule time and a control parameter input in advance. Further, the schedule management unit 305 determines whether or not the present time is highly likely to have a sudden change in the cooling load, and determines the result of whether or not it is the schedule time and the control parameter from the operation rate calculation unit 303 and the load fluctuation detection / correction To the unit 306.

  When the load fluctuation detection / correction unit 306 as a functional block composed of software obtains information from the schedule management unit 305 that the current time is within the schedule time, the fluctuation of the cooling load obtained from the operation rate calculation unit 303 suddenly changes. Judge whether or not. If the change in the cooling load changes suddenly, a correction amount is further added to the control target value calculated by the control target value determining unit 304 to control the output of the refrigerator 10. Further, when a correction amount is added to the control target value, the control target value determination unit 304 fixes the control target value to the one at the time when the correction is made.

  In addition, since the relationship between the control unit 300 and the cooling devices 2 to 6 is the same as that of the cooling device 1, the description thereof is omitted.

  Here, in the present embodiment, the control unit 300 acquires the states of the refrigerator 10 and the cooling devices 1 to 6 and determines the cooling load and the cooling capacity based on the acquired states of the refrigerator 10 and the cooling devices 1 to 6. An excess / deficiency is acquired, and the control target value of the output of the refrigerator 10 is determined based on the acquired excess / deficiency. The control unit 300 is configured to add a correction amount to the control target value and control the output of the refrigerator 10 based on the control target value and the correction amount when there is a sudden change in the cooling load. .

  Further, the control unit 300 is configured to detect a sudden change in the cooling load based on the amount of change in the cooling load, and to perform control to add a correction amount to the control target value when the sudden change is detected. Has been.

  Moreover, the control part 300 is based on the temperature change amount or temperature change rate in the fixed time of the temperature in the warehouse of the cooling devices 1-6 after progress for a fixed time after the cooling operation start of the cooling devices 1-6. It is configured to detect a sudden change.

  In addition, when the control unit 300 controls the output of the refrigerator 10 based on the control target value and the correction amount, when the temperature change amount or the temperature change rate in the refrigerators 1 to 6 changes. Is configured to update the correction amount to a correction amount corresponding to the temperature in the cabinet of the cooling devices 1 to 6.

  Further, the control unit 300 is configured to perform control to add a correction amount to the control target value in a time zone where there is a high possibility that there is a sudden change in the cooling load and when a sudden change in the cooling load is detected. ing.

  Further, the control unit 300 is configured to fix the control target value to that at the time of detecting a sudden change in the cooling load while adding the correction amount to the control target value.

(Operation of the cooling device in normal times)
First, operation | movement of the cooling device 100 in the normal time when a cooling load changes gently is demonstrated easily. In normal times, the compressor 11 and the electronic expansion valves 1b to 6b are controlled by the control device 30 according to only the control target value. The cooling devices 1 to 6 are set to certain target temperatures having ranges of an upper limit value Ton and a lower limit value Toff, respectively.

  The cooling device 100 is changing various states every moment. The control unit 300 always acquires and controls the states of the cooling devices 1 to 6 and the refrigerator 10. Here, for simplification, explanation will be made from a state in which all the temperatures in the chambers of the cooling devices 1 to 6 are within the set range of the target temperature set for each, and all the solenoid valves 1a to 6a are closed, and a while has passed. To start. Further, in the description of the operation of the cooling device 100 in the normal state, it is assumed that the temperature in the cabinet of the cooling devices 2 to 6 is always within the set range of the target temperature. In the above state, on the evaporators 1 c to 6 c side, the refrigerant between the solenoid valves 1 a to 6 a and the compressor 11 is sucked out by the compressor 11 and collected in the refrigerator 10.

  Here, as an example, a case where the temperature in the refrigerator of the cooling device 1 varies will be described. When the internal temperature of the cooling device 1 exceeds the upper limit value Ton of the target temperature setting range, the electromagnetic valve 1a is opened, and the cooling device 1 from the condenser side in which the refrigerant is included in the refrigerator 10 due to the pressure difference. Flows into the evaporator 1c side included in the air through the electromagnetic valve 1a. The pressure sensor 14 detects the suction pressure caused by the refrigerant vapor evaporated in the evaporator 1 c, and the compressor 11 starts operation under the control of the control unit 300. As a result, in the refrigeration cycle including the compressor 11, the condenser 12, the electronic expansion valve 1b, and the evaporator 1c, the refrigerant starts to be circulated in the direction of the arrow P shown in FIG. When a certain amount of time has passed, the temperature inside the refrigerator 1 starts to decrease and falls below the upper limit value Ton of the target temperature setting range. If the temperature in the chamber continues to fall further and falls below the lower limit value Toff of the target temperature setting range, the electromagnetic valve 1a is closed to stop the flow of the refrigerant. And the refrigerant | coolant by the side of the cooling device 1 is collect | recovered by the compressor 11 at the refrigerator 10 side, and since the refrigerant | coolant which flows into the evaporators 1c-6c is lose | eliminated, the suction pressure falls and the compressor 11 stops.

  Actually, since the target temperature in the warehouse of each of the cooling devices 1 to 6 is lower than the outside of the warehouse, the temperature inside the warehouse rises due to the heat entering from outside the warehouse unless the refrigerant flows. And according to the temperature in the store | warehouse | chamber of the cooling devices 1-6, the solenoid valves 1a-6a each repeat opening and closing. For this reason, the temperature inside the cabinet is constantly raised and lowered due to heat entry and the opening and closing of the solenoid valves 1a to 6a, and not all are within the set range. Therefore, it is desirable that the cooling device 100 is configured such that the output of the refrigerator 10 is not wasted as much as possible while keeping the temperature in the cabinet of each of the cooling devices 1 to 6 within the set range. Therefore, the control unit 300 controls the operating frequency of the compressor 11 (output of the refrigerator 10) and the opening degree of the electronic expansion valves 1b to 6b, and always changes the operating state to an appropriate one.

  First, when there is a large proportion of the solenoid valves 1a to 6a that have been closed for a long time, the cooling device 100 determines that the temperature in the storage when the temperature in the storage of the cooling devices 1 to 6 exceeds the set range. Can be returned to the setting range in a short time. That is, it is considered that the cooling capacity of the flowing refrigerant is too high. Therefore, in order to reduce the flow rate of the refrigerant, the control unit 300 decreases the opening degree of some of the electronic expansion valves 1b to 6b corresponding to the cooling devices 1 to 6 having a relatively low temperature in the warehouse. Alternatively, the control unit 300 performs control to lower the operating frequency of the compressor 11. On the other hand, when there is a large proportion of the solenoid valves 1a to 6a that are open for a long time, the cooling device 100 takes too much time to return the internal temperature to the set range, or the set range. I haven't been able to return to That is, it is considered that the cooling capacity of the refrigerant is insufficient. Therefore, the control part 300 increases the opening degree of some electronic expansion valves 1b-6b corresponding to the cooling devices 1-6 with comparatively high temperature in a warehouse, in order to increase the flow volume of a refrigerant | coolant. Alternatively, the control unit 300 performs control to increase the operating frequency of the compressor 11.

  Further, for example, after a while after changing the flow rate of the refrigerant, if the superheat degree of the refrigerant vapor is too high in the vicinity of the outlet of the evaporator 1c, there is room for increasing the supply of the refrigerant, and sufficient cooling efficiency is obtained. It is thought that it is not. Therefore, the controller 300 increases the opening of the electronic expansion valve 1b in order to increase the flow rate of the refrigerant toward the evaporator 1c. On the other hand, if the superheat degree of the refrigerant vapor is too low in the vicinity of the outlet of the evaporator 1c, there is a risk that the refrigerant superheated vapor entering the compressor 11 returns to the liquid. Therefore, the controller 300 decreases the opening degree of the electronic expansion valve 1b in order to reduce the flow rate of the refrigerant toward the evaporator 1c.

  Increasing the operating frequency of the compressor 11 increases the cooling capacity but increases the power consumption. For example, when the opening degree of the electronic expansion valve 1b is increased, the cooling device 1 connected to the electronic expansion valve 1b having the increased opening amount increases the flow rate of the refrigerant and increases the cooling capacity. For 6, the flow rate of the refrigerant decreases and the cooling capacity decreases. As a result, it is necessary to increase the operating frequency of the compressor 11, and the power consumption increases.

  Moreover, if the evaporation temperature of a refrigerant | coolant falls, the evaporation amount of the refrigerant | coolant in the evaporators 1c-6c will fall. As a result, the density of the refrigerant vapor in the vicinity of the outlets of the evaporators 1c to 6c is reduced, so that the amount of refrigerant sucked into the compressor 11 is reduced and the cooling capacity is lowered. Further, the suction pressure of the compressor 11 decreases.

  Therefore, the control target value determination unit 304 shifts the operation frequency of the compressor 11, which is the control target value, the suction pressure of the compressor 11, and the evaporation temperature of the refrigerant in the evaporator, and based on the control target value, the compressor 11. The operation frequency and the opening state of the electronic expansion valves 1b to 6b are controlled. Power consumption can be reduced by determining the control target value so as to keep the operating frequency of the compressor 11 as low as possible within the range in which the temperature inside the refrigerator of the cooling device can be kept within the set range. In addition, for simplification, the description has been made mainly on the cooling device 1, but the same applies to the cooling devices 2 to 6.

(Cooling device operation during load fluctuation detection / correction)
With reference to FIG. 3 to FIG. 6, the operation of the cooling device 100 at the time of load fluctuation detection / correction (at the time of detecting a sudden change in cooling load) will be described. As described above, in normal operation, the output of the refrigerator 10 is reduced to an extent necessary for maintaining the temperature in the warehouse. In addition, the cooling load is constantly changing. The control target value is calculated by an average amount at a certain time interval (for example, 30 minutes) in order to improve the efficiency of the cooling device 100. Here, for example, if the temperature of the cooling device 1 exceeds the upper limit of the set range, the electromagnetic valve 1a is opened, the refrigerant starts to flow into the evaporator 1c, and cooling of the cooling device 1 is started. However, if the internal temperature rises greatly in a short time (changes suddenly), even if cooling is performed with a low output, the cooling is not in time and the internal temperature continues to rise. When there is a sudden change in the temperature in the refrigerator, the sudden change in temperature is reflected in the output of the refrigerator 10 only by the control target value that is shifted on the premise of normal times where the inflow of heat from the outside is limited to some extent. Will be late. That is, the control target value set so as to reduce power consumption is not sufficient to follow the temperature in the cabinet. Therefore, when the cooling load increases, the output of the refrigerator 10 is increased by the control target value, and a correction amount is added in response to a sudden change in the cooling load to further increase the output.

  The determination of the correction amount for the sudden change will be specifically described with reference to FIG. The graph of FIG. 3 shows how the temperature inside the refrigerator of the cooling device 1 changes with time. From the top, the graph of the temperature change of the cooling device 1, the transition of the open / close state of the solenoid valve 1a, the transition of the control type of the cooling device 100, and the transition of the correction amount added to the control target value are shown. Initially (before time t1), the solenoid valve 1a is in a closed state, and the temperature in the refrigerator 1 is within the set range. When the internal temperature rises and the internal temperature exceeds the upper limit value Ton of the set range at time t1, the control unit 300 causes the electromagnetic valve 1a to be in the open state, and the internal cooling is started. . Even if cooling is started, the temperature does not decrease immediately, so the temperature in the cabinet continues to rise for a while, but then the temperature in the cabinet starts to decrease. At time t2, that is, when the response time tr elapses after the electromagnetic valve 1a is opened, the controller 300 acquires the temperature in the refrigerator 1 and exceeds the first threshold value T1. Judge whether or not. Since the internal temperature is equal to or lower than the first threshold T1 this time, the controller 300 determines that there is no sudden change in temperature and does not add a correction amount to the control target value. Thereafter, the temperature continues to fall. By reaching the lower limit value Toff of the setting range at time t3, the solenoid valve 1a is in a closed state. The response time tr is a certain short time, and is an example of “a certain time” in the claims.

  The internal temperature that has fallen below the set range starts to rise again, exceeds the lower limit value Toff of the set range, and stays within the set range for a while. Thereafter, at time t4, since the upper limit value Ton of the setting range is exceeded again, the controller 300 causes the electromagnetic valve 1a to be in the open state. At the time t5 when the response time tr has elapsed from the time t4, the temperature in the warehouse exceeds the first threshold value T1, so the control unit 300 (load variation detection / correction unit 306) determines that there has been a sudden change in the cooling load. For example, the first correction amount is added to the control target value of the suction pressure. As a result, the output of the refrigerator 10 that is the operating frequency of the compressor 11 is increased, and the cooling capacity of the refrigerator 10 is increased. Thereafter, the temperature inside the container begins to drop, and at time t6, the temperature falls below the lower limit value Toff of the set range, and the electromagnetic valve 1a enters the closed state.

  Thereafter, the temperature inside the chamber starts to rise again, but at time t7, the solenoid valve 1a is opened, and at time t8, the temperature inside the chamber reaches the first threshold value T1, and the control unit 300 reaches the control target value. This is substantially the same as described above until the first correction amount is added. However, after adding the first correction amount, the temperature in the refrigerator continues to rise, and thus exceeds the second threshold T2 at time t9. At this time, the control unit 300 updates the first correction amount to a second correction amount that further increases the output of the refrigerator 10. And the temperature in a warehouse begins to fall gradually. The subsequent process is the same as the others, and at time t10, the electromagnetic valve 1a is closed. When the response time tr elapses and the internal temperature is higher than the second threshold T2, the second correction amount is added from the beginning.

  Note that the control target value may drop after the correction value is added due to the balance with the other cooling devices 2 to 6. That is, there is a possibility that the output of the refrigerator 10 is lowered before the temperature of the cooling devices 1 to 6 where the cooling load (the temperature in the warehouse) has suddenly changed to the target temperature. Therefore, the control unit 300 (control target value determination unit 304) is a period from when the sudden change in the cooling load is detected until the temperature in the refrigerator 1 that has detected the sudden change falls below the lower limit value Toff of the setting range, The control target value at the time when the sudden change is detected is fixed. In addition, although the graph of FIG. 3 is linearly written for simplification, the temperature in the cabinet fluctuates while swinging up and down. Therefore, the upper limit value Ton and the lower limit value Toff, which are the upper and lower widths of the target temperature setting range, and the temperature for determining the sudden change of the cooling load and the correction amount to be added so that the cooling device 100 operates appropriately. The certain first threshold value T1 and the second threshold value T2 need to be set in accordance with the capacity and usage status of the cooling device 100. Moreover, it is necessary to set different values for each of the cooling devices 1 to 6 in accordance with the size in the cabinet, the cooling target to be put in the cabinet, the target temperature, and the like.

(Schedule management)
If comprised as mentioned above, when there exists a sudden change of the temperature in a store | warehouse | chamber, a freezing capacity can be raised immediately and the temperature in a store | warehouse | chamber can be lowered | hung to a setting range immediately. However, a large increase in the temperature in the refrigerator may be able to cope with the original output without necessarily increasing the output of the refrigerator 10 unless the frequency is so high. In that case, the effect of the control target value that is set to reduce power consumption is diminished.Therefore, when there is a high possibility that there is a sudden change in the cooling load in advance, and there is a sudden change in the cooling load. Only the correction amount is added to the control target value.

  For example, when a product is received / shipped, the heat load is increased by opening the doors of the cooling devices 1 to 6 for a long time, and when the product is received, the heat load is increased by bringing a product having a higher temperature than the inside of the warehouse. Consider the case where the temperature in the cabinet of the cooling devices 1 to 6 greatly increases in a short time. In general, the time of arrival and shipment of goods is scheduled. Therefore, the user of the cooling device 100 inputs the arrival / shipping time zone as a schedule setting in the schedule management unit 305 in advance. The schedule management unit 305 causes the load fluctuation detection / correction unit 306 to add a correction amount to the control target value when a sudden change in the cooling load is detected and within the schedule time. Even if a sudden change is detected, the correction amount is not added if it is outside the schedule time.

  For example, the schedule time is set as shown in FIG. Every day from 15:00 to 17:00 indicates the time for arrival / shipment. Moreover, it shows that the night arrival / shipment time zone is from 20:00 to 6:00 on Monday. Moreover, it is shown that it is from 19:00 to 4:00 from Tuesday to Sunday. Moreover, since December 31st is New Year's Eve, the arrival / shipping time zone is from 12:00 to 18:00.

(Specific examples of control parameters)
The response time tr, the first threshold value T1 and the second threshold value T2, and the first correction amount and the second correction amount are set as control parameters. Specifically, the control parameters are set as shown in FIG. 5, for example. However, the first deviation ΔT1 is a difference between the first threshold value T1 and the upper limit value Ton of the set temperature, and the second deviation ΔT2 is a difference between the second threshold value T2 and the upper limit value Ton of the set temperature. The cooling devices a, b, and c written on the left side represent any of the cooling devices 1 to 6. The load fluctuation detection / correction unit 306 detects the temperature in the chamber of the cooling device a after 60 seconds, which is the response time tr after the electromagnetic valve (any one of 1a to 6a) corresponding to the cooling device a is in the open state. To get. If the temperature in the refrigerator of the cooling device a is higher than the upper limit value Ton of the target temperature setting range by 2.0K, which is the first deviation ΔT1, the suction correction control target value is temporarily set as the first correction amount. Add an additional 0.2 Mpa. When the response time tr of 60 seconds elapses, if the internal temperature is higher than the upper limit value Ton of the setting range by 4.0 K which is the second deviation ΔT2, the suction pressure is set as the second correction amount. 0.4 Mpa is added to the control target value. When the first correction amount or the second correction amount is added, the control target value determination unit 304 passes the control target value as the response time tr when the first correction amount or the second correction amount is added for 60 seconds. Fix it at the time.

  Further, it is assumed that the temperature in the refrigerator of the cooling device a continues to rise even after the first correction amount is added. If the internal temperature of the cooling device a exceeds 4.0K, which is the second deviation ΔT2, from the upper limit value Ton of the setting range, the control target value determination unit 304 updates the first correction amount to the second correction amount. Then, 0.4 Mpa is added to the control target value of the suction pressure. Regardless of whether or not the second correction amount is added, if the temperature of the cooling device a falls below the lower limit value Toff of the setting range, the process of adding the correction amount is stopped and the normal operation is resumed. Further, the control target value determination unit 304 starts shifting the control target value again in order to reduce power consumption. The same applies to the cooling devices b and c in FIG. Further, the control parameter needs to be set to a different value for each of the cooling devices 1 to 6 according to the size in the cabinet and the target temperature.

(Load fluctuation detection / correction processing)
The operations of the load fluctuation detection / correction unit 306 during normal time and sudden change detection as described above are collectively controlled as load fluctuation detection / correction processing. With reference to FIG. 6, the load fluctuation detection / correction processing by the control unit 300 of the cooling device 100 will be described. Note that the load variation detection / correction process is continuously performed during operation of the cooling device 100.

  In step S1 of FIG. 6, it is determined whether or not the correction state is correction. If the correction state is not corrected (Yes), the process proceeds to step S2, and if the correction state is not corrected (No), the process proceeds to step S7.

  In step S2, it is determined whether it is within the schedule time. If it is within the schedule time (Yes), the process proceeds to step S3. If it is outside the schedule time (No), the process returns to step S1.

  In step S3, it is determined whether or not the solenoid valve 1a (2a to 6a) has been opened and the response time tr has elapsed. If the solenoid valve 1a (2a-6a) is opened and the response time tr has passed (Yes), the process proceeds to step S4. On the other hand, when the solenoid valve 1a (2a to 6a) is not opened or the response time tr has not elapsed (No), the process returns to step S1.

  In step S4, it is determined whether the internal temperature is higher than the second threshold T2. If the internal temperature is equal to or lower than the second threshold T2 (No), the process proceeds to step S5. If the internal temperature is greater than the second threshold T2 (Yes), the process proceeds to step S9.

  In step S5, it is determined whether the internal temperature is higher than the first threshold T1. If the internal temperature is greater than the first threshold T1 (Yes), the process proceeds to step S6. If the internal temperature is equal to or lower than the first threshold T1 (No), the process returns to step S1.

  In step S6, the correction amount is set to the first correction amount. In step S6, if the control target value is still being shifted, the control target value determining unit 304 fixes the control target value to that at the time when the first correction amount is added. Then, it returns to step S1.

  If it is determined in step S4 that the internal temperature is higher than the second threshold T2 (Yes), the process proceeds to step S9, and in step S9, the correction amount is set to the second correction amount. In step S9, if the control target value is still shifted, the control target value determining unit 304 fixes the control target value to the one at the time when the second correction amount is added. Then, it returns to step S1.

  If it is determined in step S1 that the correction state is not corrected (corrected) (No), the process proceeds to step S7, and in step S7, it is determined whether or not the correction state is the first correction amount. If the correction state is the first correction amount (Yes), the process proceeds to step S8, and if the correction state is not the first correction amount (No), the process proceeds to step S10.

  In step S8, it is determined whether the internal temperature is higher than the second threshold T2. If the internal temperature is higher than the second threshold T2 (Yes), the process proceeds to step S9. If the internal temperature is equal to or lower than the second threshold T2 (No), the process proceeds to step S10.

  In step S9, the correction amount is set to the second correction amount. In step S9, if the control target value is still shifted, the control target value determining unit 304 fixes the control target value to the one at the time when the second correction amount is added. Then, it returns to step S1.

  In step S10, it is determined whether or not the internal temperature is equal to or lower than the target temperature. If the internal temperature is equal to or lower than the lower limit value Toff of the target temperature setting range (Yes), the process proceeds to step S11. If the internal temperature is greater than the lower limit value Toff of the target temperature setting range (No), step S1 is performed. Return to.

  In step S11, the correction state is set without correction. In step S11, the control target value determining unit 304 is caused to start shifting the control target value again. Then, it returns to step S1.

(Effect of this embodiment)
In the present embodiment, the following effects can be obtained.

  In the present embodiment, as described above, when there is a sudden change in the cooling load, a correction amount is added to the control target value, and the output of the refrigerator 10 is controlled based on the control target value and the correction amount. The part 300 is provided. Thereby, if a sudden change is detected in the cooling load, a correction amount can be added to the control target value, and the output (cooling capacity) of the refrigerator 10 can be temporarily increased according to the sudden change. Even when there is a sudden change, the followability of the output of the refrigerator 10 with respect to the cooling load can be improved. Further, the control unit 300 lowers the operating frequency of the compressor 11 included in the refrigerator 10 that is the control target value when the cooling capacity is excessive, and the compressor 300 when the cooling capacity is insufficient. 11 is increased, the output of the refrigerator 10 with respect to the cooling load can be kept appropriate in a normal state where there is no sudden change in the cooling load. In this case, power consumption can be reduced if the output of the refrigerator 10 is reduced to an extent necessary for maintaining the temperature.

  In the present embodiment, as described above, the control unit 300 detects the sudden change of the cooling load based on the change amount or the change rate of the cooling load, and controls the control unit 300 when the sudden change is detected. Control is performed to add a correction amount to the target value. Accordingly, it is possible to easily detect a sudden change in the cooling load by determining whether or not the amount or rate of change of the cooling load exceeds a certain threshold value, for example.

  Further, in the present embodiment, as described above, the control unit 300 is configured to change the temperature change amount in a certain time of the temperature in the warehouse of the cooling devices 1 to 6 after a certain time has elapsed after the start of the cooling operation of the cooling devices 1 to 6 or Based on the rate of temperature change, a sudden change in the cooling load is detected. As a result, the cooling load increases as the internal temperature of the cooling devices 1 to 6 rises. Therefore, the cooling load can be easily cooled by determining whether the temperature change amount or the temperature change rate exceeds a certain threshold value, for example. A sudden change in load can be detected.

  In the present embodiment, as described above, when the control unit 300 controls the output of the refrigerator 10 based on the control target value and the correction amount, the temperature change in the refrigerator of the cooling devices 1 to 6 is performed. When the amount or the temperature change rate changes, the correction amount is updated to a correction amount corresponding to the temperature in the refrigerator of the cooling devices 1 to 6. As a result, the correction amount is updated when the temperature in the cooling devices 1 to 6 increases after the start of the cooling operation corresponding to the sudden change in the cooling load, and the cooling load further increases. The output of the machine 10 can be followed more appropriately.

  Further, in the present embodiment, as described above, the control unit 300 is corrected to the control target value in a time zone in which there is a high possibility that there is a sudden change in the cooling load and when a sudden change in the cooling load is detected. It is configured to perform control to add an amount. As a result, the follow-up performance of the output of the refrigerator 10 can be improved in a time zone in which there is a high possibility of sudden changes in the cooling load and when sudden changes in the cooling load are detected. It is possible to prevent the output of the machine 10 from being in time for the increase in cooling load. Further, since the correction amount is not used in the time zone when the cooling load is stable and the sudden change of the cooling load hardly occurs, the power consumption can be reduced by keeping the output of the refrigerator 10 low. be able to.

(Modification)
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example in which the correction amount is the suction pressure of the compressor 11 is shown, but the present invention is not limited to this. A correction amount may be added to the control target value for the operating frequency of the compressor 11 and the evaporation temperature in the evaporators 1c to 6c. Alternatively, if there are a plurality of compressors 11, the number of operating compressors 11 may be handled as the control target value, and the number of operating compressors 11 may be increased as the correction amount.

  Moreover, in the said embodiment, the sudden change of a cooling load is judged by whether any one of the cooling devices 1-6 had a sudden change in the schedule time, and in that case, for every corresponding cooling devices 1-6 Although an example in which the fixed first correction amount or the second correction amount is added has been shown, the present invention is not limited to this. If the number of the cooling devices 1 to 6 in which a sudden change in the cooling load is detected increases, the correction amount to be added may be updated to a larger one. Further, the temperature threshold value for determining the correction amount to be added may be increased to the third threshold value, the fourth threshold value, and the corresponding correction amount may be increased to the third correction amount, the fourth correction amount, and so on.

  Moreover, although the example which does not change a control parameter during a schedule time slot | zone was shown in the said embodiment, this invention is not limited to this. A configuration may be adopted in which the control parameter is changed for each schedule time.

  In the above embodiment, the sudden change of the cooling load is determined by whether or not the first temperature threshold value is exceeded after the response time tr, which is a fixed time, has elapsed after the internal temperature exceeds the upper limit value Ton of the setting range. However, the present invention is not limited to this. Obtain the average temperature in the warehouse for a short period of time that can handle sudden changes in the cooling load before and after the temperature in the warehouse exceeds Ton, and calculate the sudden change in cooling load from the rate of temperature change in the warehouse during that period. It may be configured as desired. In this case, the load variation detection / correction unit 306 may be configured to add a correction amount if the temperature change rate is larger than a certain threshold value.

  In the above embodiment, the example in which the user of the cooling device 100 inputs the arrival / shipping time zone as the schedule setting in advance to the schedule management unit 305 is shown, but the present invention is not limited thereto. Absent. It is not necessary to input the schedule settings manually, for example, it communicates with a computer equipped in a transport vehicle, etc., obtains the estimated shipping time and the amount of incoming / shipped packages, and is calculated from the acquired information You may comprise so that it may update automatically in a time slot.

  In the above embodiment, for convenience of explanation, the processing of the control unit 300 has been described using the “flow drive type” flowchart, but the present invention is not limited to this. You may perform by the "event drive type" which performs the process of the control part 300 per event. In this case, it may be performed by a complete event drive type or a combination of event drive and flow drive.

1-6 Cooling equipment 10 Refrigerator 30 Control device 100 Cooling device 300 Control unit

Claims (7)

A refrigerator,
A cooling device cooled by the refrigerator;
The state of the refrigerator and the cooling device is acquired, the cooling load and the cooling capacity are acquired based on the acquired state of the refrigerator and the cooling device, and the refrigerator is acquired based on the acquired excess and shortage. A control unit for determining a control target value of the output of
The control unit is configured to add a correction amount to the control target value and control the output of the refrigerator based on the control target value and the correction amount when there is a sudden change in the cooling load. The cooling device.   The control unit detects a sudden change in the cooling load based on a change amount or a change rate of the cooling load, and adds the correction amount to the control target value when the sudden change is detected. The cooling device according to claim 1, wherein the cooling device is configured to perform.   The control unit detects a sudden change in the cooling load based on a temperature change amount or a temperature change rate of the temperature in the storage of the cooling device after a certain time has elapsed after the start of the cooling operation of the cooling device. The cooling device according to claim 2, configured as described above.   When the control unit controls the output of the refrigerator based on the control target value and the correction amount, when the temperature change amount or the temperature change rate in the refrigerator of the cooling device changes, The cooling device according to claim 3, wherein the correction amount is configured to update the correction amount to a correction amount corresponding to a temperature inside the storage of the cooling device.   The control unit performs control to add the correction amount to the control target value in a time zone in which there is a high possibility that there is a sudden change in the cooling load and when a sudden change in the cooling load is detected. The cooling device according to any one of claims 1 to 4, wherein the cooling device is configured.   The said control part is comprised so that the said control target value may be fixed to the thing at the time of detecting the sudden change of the said cooling load, while adding the said corrected amount to the said control target value. The cooling device according to any one of the above. Obtaining the state of the refrigerator and the cooling device, obtaining the excess or deficiency of the cooling load and the cooling capacity based on the obtained state of the refrigerator and the cooling device, and outputting the output of the refrigerator based on the obtained excess or deficiency A control unit for determining the control target value of
The control unit is configured to add a correction amount to the control target value and control the output of the refrigerator based on the control target value and the correction amount when there is a sudden change in the cooling load. The control unit.

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