JP2017122524A - Freezing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezing system that can reduce total running cost by suppressing power peak and stabilizing a driving motion.SOLUTION: The freezing system includes: a refrigeration machine 10 in which a heat exchanger is connected to a discharge side of a compressor 11 and refrigerant is encapsulated; evaporators 41 for a plurality of show cases 40 connected between the refrigeration machine 10 and a suction port of the compressor 11; and a control device 36 that divides the plurality of show cases 40 into groups and controls preset temperature to change for each group of the show cases 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a refrigeration system, and more particularly to a refrigeration system that can reduce the total running cost by suppressing power peaks and stabilizing the operation.

  Conventionally, in stores such as supermarkets and convenience stores, refrigeration systems for cooling refrigeration / frozen showcases and the like are often used. In such a refrigeration system, for example, when a large number of showcases are installed, the setting temperature of each showcase is basically not frequently changed after the initial setting. In addition, when setting changes are made due to operational requirements, the settings are not changed for each showcase, but are collectively changed for a set number of showcases, such as a specified group unit or type unit. Like to do.

  As a technique for performing such batch setting change, conventionally, for example, an operation control device is provided for each showcase, and a central control device connected to the operation control device via a transmission line is installed in the machine room. A group setting device that divides showcases with the same operating conditions into groups for each group, a mode setting device that sets the operation mode of each showcase, and a timer device that counts the operation start and stop times for each group A technique is disclosed in which the operation is started and stopped at the time set in the operation mode set by the output from the central control device to the operation control device of each showcase (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 06-018137

In the invention described in Patent Document 1, a plurality of freezing and refrigeration showcases are installed, and even if the operating conditions of these showcases are different, all the showcases are non-cooled and non-cold stopped. Management can be performed intensively and workability can be improved.
However, for example, when a set number of units are controlled at a time according to a change in set temperature, there is a problem that a load fluctuation is large, a power peak may be caused by a reaction, and an operation operation is not stable. As a result, there is a problem that the total running cost increases and energy saving cannot be achieved.

  The present invention has been made in view of the above points, and an object thereof is to provide a refrigeration system capable of reducing the total running cost by suppressing the power peak and stabilizing the operation. Yes.

  In order to achieve the above object, a refrigeration system according to the present invention includes a refrigerator that connects a heat exchanger to a discharge side of a compressor and encloses a refrigerant, and is connected between the refrigerator and a suction port of the compressor. A plurality of showcase evaporators, and a control device that divides the plurality of showcases into groups and performs a change control of a set temperature for each showcase of the group.

  The present invention is characterized in that, in the above configuration, the control device sequentially switches the change control of the set temperature according to a predetermined control time for each showcase of each group.

  The present invention is characterized in that, in the above configuration, the control device performs change control of the set temperature at a set control target.

  The present invention is characterized in that, in the above configuration, the control device performs change control of the set temperature at the time of constant control.

  The present invention is characterized in that, in the configuration described above, the group includes one or several showcases.

  The refrigerant is a carbon dioxide refrigerant.

  According to the present invention, since the control device performs the control of changing the set temperature for each divided showcase of each group, the peak of the cooling load can be suppressed. Thus, the total cooling load can be made constant. Therefore, since the peak of the cooling load can be suppressed, the occurrence of a power peak can be suppressed and the running cost can be reduced.

It is a refrigerating cycle figure showing an embodiment of a refrigerating system concerning the present invention. It is a timing chart which shows the example of control for every group in an embodiment. It is a flowchart which shows the operation | movement at the time of the control object by demand control in embodiment. It is a flowchart which shows the operation | movement at the time of the regular control in embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram of a refrigeration cycle showing an embodiment of a refrigeration system according to the present invention.
The refrigeration system includes a refrigerator 10 that cools the refrigerant, and a showcase 40 that is cooled by the refrigerant sent from the refrigerator 10. In the present embodiment, carbon dioxide refrigerant is used as the refrigerant.

  The refrigerator 10 includes a compressor 11 that is compressed in two stages. A refrigeration side heat exchanger 12 is connected to the compressor 11 via a refrigerant pipe 13, and the refrigeration side heat exchanger 12 includes a gas cooler 14, an intercooler 15, an oil cooler 16, and a blower fan 17. It is configured.

The compressor 11 is provided with a first suction port 20 and a first discharge port 21 in the first stage compression mechanism, and a second suction port 22 and a second discharge port 23 in the second stage compression mechanism. It has been. The first suction port 20 of the compressor 11 sucks the refrigerant sent from the evaporator 41 of the showcase 40, compresses it to an intermediate pressure by the first stage compression mechanism, and discharges it from the first discharge port 21. It is configured.
The first discharge port 21 of the compressor 11 is connected to the inlet side of the intercooler 15 via the refrigerant pipe 13, and the second outlet of the compressor 11 is connected to the outlet side of the intercooler 15 via the refrigerant pipe 13. Connected to the inlet 22.

  The second discharge port 23 of the compressor 11 is connected to the oil separator 24 via the refrigerant pipe 13, and the oil separator 24 is connected to the intercooler 15 via the refrigerant pipe 13. The oil separator 24 separates and stores the oil in the refrigerant. The oil separator 24 is connected to the inlet side of the oil cooler 16 via the oil feed pipe 25, and the outlet side of the oil cooler 16 is The compressor 11 is connected to the compressor 11 through an oil return pipe 26.

Then, the refrigerant discharged from the first discharge port 21 of the compressor 11 flows into the intercooler 15 through the refrigerant pipe 13 and is cooled by exchanging heat with the outside air by operating the blower fan 17 in the intercooler 15. The compressor 11 is configured to be returned to the second suction port 22. Then, the compressor 11 is compressed to a necessary pressure by the second stage compression mechanism and discharged from the second discharge port 23, and is joined to the gas cooler 14 via the oil separator 24. Yes.
The oil separator 24 separates and stores oil in the refrigerant. The oil in the oil separator 24 is sent to the oil cooler 16 through the oil feed pipe 25, and the air cooler 16 is cooled by exchanging heat with the outside air by operating the blower fan 17. Through the intermediate stage of the compressor 11.

  The gas cooler 14 cools the refrigerant sent from the compressor 11 by exchanging heat with the outside air by operating the blower fan 17. However, since the carbon dioxide refrigerant is not condensed, it is a high-pressure gas in a supercritical state. It will be sent as it is.

  Further, an economizer 30 is connected to the gas cooler 14 via the refrigerant pipe 13. The refrigerant pipe 13 on the outlet side of the economizer 30 is provided with a branch pipe 31 branched from the refrigerant pipe 13, and the branch pipe 31 is connected to the economizer 30 via a branch pipe expansion valve 32. The refrigerant pipe 13 and the branch pipe 31 are arranged so that the direction in which the refrigerant flows is an opposite flow, and the refrigerant flowing through the refrigerant pipe 13 and the refrigerant flowing through the branch pipe 31 can efficiently exchange heat. It is configured to be able to.

  A branch pipe 31 on the outlet side of the economizer 30 is connected to the outlet side of the intercooler 15. The branch pipe expansion valve 32 decompresses the high-pressure refrigerant on the outlet side of the economizer 30 and expands it to an intermediate pressure level. The economizer 30 decompresses the high-pressure refrigerant that flows through the refrigerant pipe 13 and the branch pipe 31. The high-pressure refrigerant is cooled by exchanging heat with the refrigerant. The decompressed refrigerant after the heat exchange joins with the refrigerant on the outlet side of the intercooler 15 and is sent to the compressor 11 from the second suction port 22 respectively, and the temperature and intermediate pressure of the refrigerant discharged from the compressor 11 are optimized. It is designed to make it easier.

  A refrigerant quantity adjustment tank 34 is connected to the branch pipe 31 on the inlet side of the economizer 30. The refrigerant amount adjustment tank 34 is connected to the inlet side of the economizer 30 via a refrigerant return pipe 35. In the present embodiment, the refrigerant amount adjustment tank 34 is configured to adjust the refrigerant amount according to the load of the evaporator 41.

  An evaporator 41 of a plurality of showcases 40 is connected to the refrigerant pipe 13 on the outlet side of the economizer 30 via an expansion valve 42, and the refrigerant sent from the refrigerant pipe 13 by the evaporator 41 and the air in the cabinet. And the interior of each showcase 40 is cooled. The outlet side of the evaporator 41 is connected to the first suction port of the compressor 11 via the refrigerant pipe 13.

Furthermore, in this embodiment, the control apparatus 36 which performs control of the refrigeration system comprised as mentioned above is provided. The control device 36 controls the operation control of the compressor 11 of the cooling system, the operation control of the blower fan 17, the opening / closing control of the expansion valve 42, and the like based on the refrigerant temperature, the internal temperature of the showcase 40, and the like.
In the present embodiment, all the showcases 40 are divided into a plurality of fine groups composed of a plurality of showcases 40, and the temperature is controlled for each group by the control device 36. In addition, in this embodiment, the example at the time of dividing the ten showcases 40 into five groups (group 1-group 5) of two each is shown.

  The control device 36 controls the temperature change for each of the divided showcases 40 of each group, for example, at the time of control by predetermined demand control or at the time of constant control, and the temperature for the showcases 40 of each group. The change control is configured to be sequentially shifted. Furthermore, the predetermined control time per showcase 40 of each group by the control device 36 is set to a short time, for example, about 5 minutes, and the control for the showcase 40 of each group is switched according to this control time. It is configured. In this way, by switching and controlling each showcase 40 of each group for each control time, the total cooling load for the showcase 40 can be made constant.

In the present embodiment, when demand control is performed according to the control target time, the control target time for performing demand control is set in advance. For example, a period during which a power peak in summer or winter may occur may be set as a control target time according to the date. Moreover, you may make it set the time slot | zone when there is a high possibility that an electric power peak generate | occur | produces, such as the daytime of summer, the morning and evening of winter, as a control object time within one day. Further, the outside air temperature is detected, and when the outside air temperature is equal to or higher than a predetermined threshold in the summer, or when it is equal to or lower than the predetermined threshold in the winter, it is automatically set as the control target. Good. In addition, for example, when the power consumption per predetermined unit time such as one hour or 30 minutes is equal to or greater than a threshold value, it may be automatically set as a control target.
As described above, the determination condition as to whether or not to be set as a control target may be set according to the use environment, or the control target time may be set by combining these conditions.

A specific control example by the control device 36 will be described with reference to FIG. When the preset control target time is reached, the control device 36 sets, for example, the set temperature of the group 1 showcase 40 higher by 1 ° C. For example, after this control is continued for a short time of about 5 minutes, the set temperature of the showcase 40 of group 1 is returned to the original set temperature.
At the same time, similarly for the showcase 40 of group 2, the set temperature is set higher by 1 ° C. In this way, the change control of the set temperature is sequentially performed for each showcase 40 of each group.

In this case, the control device 36 is controlled to set the set temperature of the showcase 40 to be 1 ° C higher, but instead of setting the set temperature to be 1 ° C higher, the operation of the showcase 40 is controlled to be OFF. Also good.
In the case of performing such control, for example, the control device 36 controls the operation of the showcase 40 of group 1 to be OFF, for example, and continues this control for a short time of about 5 minutes, for example. 1 showcase 40 is turned on.
At the same time, the operation of the showcase 40 of group 2 is similarly controlled to be OFF. In this way, the ON / OFF control of the operation may be sequentially performed for each showcase 40 of each group.

In addition, the change amount of the set temperature of the showcase 40 of each group is not limited to 1 ° C., and may be changed by 2 ° C. or more, for example. Further, the same amount of temperature change may be applied to each group of showcases 40, or different temperature changes may be used for each group of showcases 40.
Further, the temperature control switching of the showcase 40 of each group is performed every short time of about 5 minutes, but this switching time may be less than 5 minutes or longer than 5 minutes. This switching time may be set to the same time for each group of showcases 40, or may be set to a different time for each group of showcases 40.

In addition, the control may be always performed instead of performing the control when the demand is controlled. The control at the time of the constant control is basically the same as the control performed when the demand is controlled. That is, even during regular control, the control device 36 sets, for example, the set temperature of the showcase 40 of group 1 higher by 1 ° C. For example, after this control is continued for a short time of about 5 minutes, the set temperature of the showcase 40 of group 1 is returned to the original set temperature. At the same time, similarly for the showcase 40 of group 2, the set temperature is set higher by 1 ° C. Thus, the change control of the set temperature is sequentially performed for each showcase 40 of each group.
In this case, similarly, the control device 36 may control the showcase 40 to be turned off instead of setting the set temperature of the showcase 40 higher by 1 ° C.

Next, the operation of this embodiment will be described.
First, by operating the compressor 11, the refrigerant sent from the refrigeration cooler is sucked from the first suction port 20 of the compressor 11, and this refrigerant is compressed to an intermediate pressure by the first stage compression mechanism. And discharged from the first discharge port 21.
The refrigerant discharged from the first discharge port 21 of the compressor 11 flows into the intercooler 15 through the refrigerant pipe 13, and is cooled by exchanging heat with the outside air by the blower fan 17 in the intercooler 15. The second suction port 22 is returned.

The refrigerant returned from the intercooler 15 is compressed by the compressor 11 to a required pressure by the second-stage compression mechanism, discharged from the second discharge port 23, and sent to the gas cooler 14 through the oil separator 24. The refrigerant sent from the compressor 11 is cooled by exchanging heat with the outside air by the blower fan 17 by the gas cooler 14 and sent to the economizer 30 as a high-pressure refrigerant.
This refrigerant is cooled by exchanging heat with the refrigerant branched from the refrigerant pipe 13 by the economizer 30 and decompressed via the branch pipe expansion valve 32.

  The refrigerant sent from the economizer 30 is sent to the evaporator 41 of each showcase 40 via the expansion valve 42, and the evaporator 41 cools the inside by exchanging heat with the inside air. The refrigerant after heat exchange in the evaporator 41 is returned to the compressor 11 via the refrigerant pipe 13.

  Next, the control operation in the present embodiment will be described with reference to the flowcharts shown in FIGS.

First, as shown in FIG. 3, the control device 36 determines whether or not it is a control target time (ST1), and when it is not a control target time (ST1: NO), as shown in FIG. Wait for a predetermined time, for example, 5 × n minutes (ST2).
On the other hand, if it is a control target time (ST1: YES), first, the set temperature of the showcase 40 of group 1 is set higher by 1 ° C. (ST3). For example, after this control is continued for a short time of about 5 minutes, the set temperature of the showcase 40 of group 1 is returned to the original set temperature (ST3). Subsequently, similarly for the showcase 40 of group 2, the set temperature is set higher by 1 ° C. (ST4). After this control is continued for a predetermined time, the set temperature of the showcase 40 of group 2 is returned to the original set temperature (ST4).

  Thereafter, the set temperature of the showcase 40 of group 3 is also set higher by 1 ° C., and after this control is continued for a predetermined time, the set temperature of the showcase 40 of group 3 is returned to the original set temperature (ST5). This is repeated for the showcases 40 of all groups (up to group n) (ST6).

  Further, at the time of constant control, as shown in FIG. 4, the control device 36 first sets the set temperature of the showcase 40 of group 1 higher by 1 ° C. (ST10). For example, after this control is continued for a short time of about 5 minutes, the set temperature of the showcase 40 of group 1 is returned to the original set temperature (ST10). Subsequently, similarly for the showcase 40 of group 2, the set temperature is set higher by 1 ° C. (ST11). After this control is continued for a predetermined time, the set temperature of the showcase 40 of group 2 is returned to the original set temperature (ST11). Subsequently, the group 3 showcases 40 are also controlled so that the set temperature is set higher by 1 ° C., and after this control is continued for a predetermined time, the set temperature of the group 3 showcases 40 is returned to the original set temperature. (ST12) This is repeated for the showcases 40 of all groups (up to group n) (ST13).

As described above, according to the embodiment to which the present invention is applied, the control device 36 controls the temperature change for each of the divided showcases 40 at the time of the control target or the constant control, When the predetermined control time has elapsed, the temperature change control is sequentially switched to the next group of showcases 40, so that the peak of the cooling load can be suppressed. The total cooling load can be made constant. Therefore, since the peak of the cooling load can be suppressed, the occurrence of a power peak can be suppressed and the running cost can be reduced. In particular, it is effective for suppressing power peaks at the time of control, and is effective for suppressing running power at the time of constant control.
Moreover, the fluctuation | variation of the temperature in a store | warehouse | chamber becomes small, and the influence of the temperature to the goods in the storehouse of the showcase 40 can be suppressed to the minimum.
Further, in the case of a refrigeration system using a carbon dioxide refrigerant as a refrigerant, it becomes a system that is easily affected by load fluctuations. Therefore, by performing control according to this embodiment, the total cooling load can be made constant while In addition, a control effect can be obtained.

In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.
For example, in the above embodiment, an example of a refrigerator that uses carbon dioxide as the refrigerant and is suitable for the carbon dioxide refrigerant has been described, but the present invention is not limited to this. That is, the present invention can also be applied to a refrigeration system using another refrigerant as a refrigerant and using a refrigerator suitable for the refrigerant.

DESCRIPTION OF SYMBOLS 10 Refrigerator 11 Compressor 12 Refrigeration side heat exchanger 13 Refrigerant piping 14 Gas cooler 15 Intercooler 16 Oil cooler 17 Blower fan 20 1st inlet 21 First outlet 22 Second inlet 23 Second outlet 24 Oil separator 30 Economizer 31 Branch pipe 32 Branch pipe expansion valve 33 Second branch pipe 34 Refrigerant amount adjustment tank 35 Refrigerant return pipe 36 Controller 40 Showcase 41 Evaporator 42 Expansion valve

Claims (6)

A refrigerator having a refrigerant sealed by connecting a heat exchanger to the discharge side of the compressor, and a plurality of showcase evaporators connected between the refrigerator and the suction port of the compressor,
A refrigeration system comprising: a control device that divides the plurality of showcases into groups and performs control for changing a set temperature for each showcase of the group.   The refrigeration system according to claim 1, wherein the control device sequentially switches the change control of the set temperature for each showcase of each group according to a predetermined control time.   The said control apparatus performs the change control of the said setting temperature at the time of the set control object, The refrigeration system of Claim 1 or Claim 2 characterized by the above-mentioned.   The refrigeration system according to claim 1 or 2, wherein the control device performs change control of the set temperature at the time of constant control.   The refrigeration system according to any one of claims 1 to 4, wherein the group includes one or several showcases.   The refrigeration system according to any one of claims 1 to 5, wherein the refrigerant is a carbon dioxide refrigerant.

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