JP5748563B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus, for example, a refrigeration apparatus using a refrigeration cycle having a plate heat exchanger as an evaporator.

  As a conventional refrigeration apparatus, for example, “a refrigeration apparatus using a plate heat exchanger as an evaporator, and the temperature of the medium to be cooled or an alternative characteristic related thereto is measured by a measuring means every predetermined time, and the result is The temperature of the medium to be cooled or the value of the alternative characteristic after a predetermined time is predicted, and the operation of the refrigeration apparatus is stopped when the predicted value is equal to or lower than the freezing abnormality set value (see Patent Document 1). .

  In such a case, “the plate type heat exchanger can be surely stopped before the plate heat exchanger reaches the freezing abnormality, and the medium to be cooled is frozen inside the plate heat exchanger 4. It is possible to prevent puncture of the heat exchanger 4 and a decrease in freezing capacity ”(see Patent Document 1).

  Further, as a refrigeration apparatus monitoring system, for example, “the cooling apparatus 100 has a refrigeration cycle means including a compressor 1, a condenser 2, a throttle means 4, and an evaporator 5, and a blower 3 that blows air to the condenser 2 The low-pressure refrigerant liquid temperature detecting means 10 for detecting the temperature of the low-pressure refrigerant liquid flowing into the evaporator 5 and the cooled fluid inflow temperature detecting means 11 for detecting the temperature of the cooled fluid flowing into the evaporator 5 are installed. The detected value is input to the calculation unit 21, and the determination unit 23 determines whether the fluid to be cooled is “freezing” or “possibility of freezing”. The control unit 24 controls the compressor 1, the blower 3, the throttle means 4, and the pump 6 in order to prevent the fluid to be cooled from freezing based on the determination result of the determination unit 23. Moreover, when it reaches freezing, an alarm is issued by the notification unit 25 (see Patent Document 2).

  In such a case, “this invention is based on an operating state quantity that varies depending on the low-pressure refrigerant temperature and the inflow temperature of the cooled fluid when the evaporator (same as the water heat exchanger) is close to the freezing condition. It is said that it is possible to avoid freezing of the fluid to be cooled by controlling at least one of the blowing amount, the opening area of the throttle means, or the delivery amount of the fluid to be cooled ”(see Patent Document 2). .

JP 2003-287291 A (summary, FIG. 1) JP 2009-243828 (Summary, FIG. 1)

  However, in patent document 1, although there exists a refrigerant | coolant side heat-transfer performance fall by lack of refrigerant supply, or a water-side heat-transfer performance fall by freezing as a factor which the suction pressure of a compressor falls, based on which factor The operation of the refrigeration apparatus was stopped without distinguishing whether the suction pressure of the compressor was reduced. Therefore, even when the refrigerant-side heat transfer performance decline due to the delay in the follow-up of the expansion valve control that allows the operation to continue, it is regarded as a freezing abnormality and the freezing operation is stopped. there were.

  That is, the operation of the refrigeration apparatus is stopped even though the operation of the refrigeration apparatus may be continued only by reducing the suction pressure of the compressor. In short, conventionally, when the suction pressure of the compressor is lowered, it is regarded as a freezing abnormality, and the operation of the refrigeration apparatus is stopped ignoring the case where the refrigeration apparatus can be continuously operated.

  Further, even in Patent Document 2, when the suction pressure of the compressor is reduced without distinguishing between the refrigerant-side heat transfer performance reduction and the water-side heat transfer performance reduction, it is considered that the condition is close to the condition where the evaporator freezes. There was a problem that the rotational speed of the machine was lowered and the operating capacity of the compressor was reduced.

  The present invention has been made to solve the above-described problems, and in particular, a refrigeration apparatus capable of controlling a compressor by distinguishing between refrigerant-side heat transfer performance deterioration and water-side heat transfer performance deterioration. The purpose is to provide.

The refrigeration apparatus according to the present invention includes a refrigeration cycle apparatus that forms a refrigeration cycle in which a compressor, a condenser, an expansion valve, and a plate heat exchanger are sequentially connected by a refrigerant pipe, and a refrigerant temperature on a suction side of the compressor Refrigerant temperature detecting means for detecting refrigerant, refrigerant pressure detecting means for detecting refrigerant pressure on the suction side of the compressor, refrigerant pressure detected by the refrigerant pressure detecting means, and refrigerant detected by the refrigerant temperature detecting means Control means for calculating a refrigerant superheat degree of the compressor based on the temperature and controlling a capacity of the compressor based on the refrigerant pressure and the refrigerant superheat degree, the control means comprising the refrigerant When the pressure is lower than the freezing abnormality set value corresponding to the case where the outlet temperature of the plate heat exchanger is regarded as freezing abnormality, and the refrigerant superheat degree is the freezing abnormality of the plate heat exchanger When the degree of superheat is greater, the capacity of the compressor is reduced, the heat transfer performance on the refrigerant side of the plate heat exchanger is considered to be degraded, the refrigerant pressure is smaller than the freezing abnormality set value, and The operation of the compressor is stopped when the refrigerant superheat degree is equal to or lower than the superheat degree .

  The present invention can control the compressor by distinguishing between refrigerant-side heat transfer performance reduction and water-side heat transfer performance reduction. Therefore, the refrigeration apparatus can be operated with high efficiency.

It is a block diagram which shows the freezing apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the whole process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the driving | operation start process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the normal driving | operation process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the data acquisition process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the arithmetic processing which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the comparison process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the determination process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the compressor capacity reduction process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the compressor capacity | capacitance adjustment process which concerns on Embodiment 1 of this invention. It is a flowchart which shows the detail of the compressor capacity reduction process which concerns on Embodiment 2 of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a refrigeration apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating a refrigeration apparatus according to Embodiment 1 of the present invention. The refrigeration apparatus 1 shown in the figure includes a refrigeration cycle apparatus 1 a and a control device 8.

  That is, the refrigeration cycle apparatus 1a is configured by sequentially connecting a compressor 2, a condenser 3, an expansion valve 4, and a plate heat exchanger 5 through refrigerant pipes. A temperature detector 6 and a pressure detector 7 are provided on the suction side of the refrigerant pipe connected to the compressor 2. The detection results detected by the temperature detector 6 and the pressure detector 7 are input to the control device 8 described in detail later.

  Next, the flow of the refrigerant in the refrigeration cycle apparatus 1a will be described. The high-temperature and high-pressure refrigerant discharged from the compressor 2 is condensed in the condenser 3, and then decompressed by the expansion valve 4 to become a low-temperature and low-pressure refrigerant and flows into the plate heat exchanger 5. Then, the low-temperature and low-pressure refrigerant becomes an evaporated refrigerant by heat exchange with the fluid to be cooled flowing through the plate heat exchanger 5, and is returned to the compressor 2. A series of refrigeration cycles are thus formed. Here, as shown in FIG. 1, the flow of the refrigerant is indicated by an arrow without a symbol.

  Next, each structure of the refrigeration cycle apparatus 1a will be described.

  The compressor 2 is a compressor whose operating capacity can be varied, for example, a positive displacement compressor driven by a motor (not shown) controlled by an inverter. In addition, the compressor 2 is not limited to a positive displacement compressor, For example, a centrifugal compressor may be sufficient. Further, the control of the operating capacity of the compressor 2 is not limited to the control by the inverter. For example, by opening the intake valve of the compressor by an unloader such as a multi-cylinder compressor, the number of working cylinders is reduced. The capacity may be changed step by step. Moreover, you may make it control a capacity | capacitance steplessly within a certain range with a slide valve like a screw compressor. Further, the number of compressors is not limited to one. For example, a configuration in which two or more compressors are connected in parallel or in series may be used.

  The condenser 3 is a heat exchanger that converts the high-temperature and high-pressure refrigerant compressed by the compressor 2 by cooling with water or air into a high-temperature and high-pressure refrigerant.・ Tube type heat exchanger. Note that the condenser may be any of an air cooling type, a water cooling type, and an evaporation type.

  The expansion valve 4 is an expansion valve capable of adjusting the flow rate of the refrigerant flowing in the refrigerant pipe and having a function of converting the high-temperature and high-pressure refrigerant condensed by the aggregator into a low-temperature and low-pressure refrigerant. . For the throttle adjustment of the expansion valve 4, for example, an electronic expansion valve capable of adjusting the opening of the throttle by a stepping motor (not shown) is used. The throttle adjustment is not limited to the electronic expansion valve, and may be a mechanical expansion valve or a capillary tube, for example.

  The expansion valve 4 adjusts the refrigerant supply amount based on a predetermined calculation result by the control device 8. That is, as shown in FIG. 1, the control device 8 uses a refrigerant temperature detected by the temperature detector 6 and a refrigerant pressure detected by the pressure detector 7 to perform a predetermined calculation as will be described in detail later. I do. As a result, the degree of refrigerant superheat is calculated. Then, the control device 8 expands a command for adjusting the refrigerant supply amount so as to achieve a predetermined refrigerant superheat degree based on a result of comparison of the refrigerant superheat degree on the outlet side of the plate heat exchanger 5 with a predetermined condition described later. Take out to valve 4. Thereby, the expansion valve 4 adjusts the refrigerant flow rate.

  The plate heat exchanger 5 is used as an evaporator. The plate-type heat exchanger 5 referred to here is, for example, a large number of thin plates arranged at intervals, the peripheral portion is sealed, and a space formed between the thin plates is alternately formed between a low-pressure refrigerant channel and a water channel. It is a heat exchanger which becomes. In addition, in this embodiment, although the plate type heat exchanger 5 is only one piece, it is not limited to this. For example, the structure by which the 2 or more plate type heat exchanger 5 was connected in parallel or in series may be sufficient.

  The fluid to be cooled flowing through the plate heat exchanger 5 is, for example, water mixed with an additive that lowers the freezing point, and may be simple water. Examples of the refrigerant used in the refrigeration apparatus include HFC refrigerants such as R410A, R407C, and R404A, HCFC refrigerants such as R22 and R134a, or natural refrigerants such as hydrocarbon and helium. In other words, for example, if the refrigerant is R407C, the refrigerant pressure in the normal operation is about 0.4 to 0.5 MPa. Needless to say, this pressure value varies depending on the type of refrigerant.

  Here, in the plate heat exchanger 5, the fluid to be refrigerated is circulated through a refrigerant pipe and a pump (not shown). The to-be-cooled fluid cooled by the evaporation of the refrigerant in the plate heat exchanger 5 is led to a cooling load such as a refrigerator or an indoor unit (not shown) via the refrigerant pipe.

  As described above, the refrigeration apparatus 1 is provided with the temperature detector 6 and the pressure detector 7 on the suction side of the compressor 2 in order to determine the adjustment amount of the opening degree of the expansion valve 4. . Further, the temperature detector 6 and the pressure detector 7 transmit detection results to the control device 8 as needed. Then, by using the refrigerant temperature and the refrigerant pressure detected here, as will be described later, it can be seen whether the decrease in the refrigerant pressure is a decrease in the water-side heat transfer performance due to freezing.

  That is, a factor for reducing the suction pressure of the compressor 2 is distinguished. Thereby, it is distinguished whether the heat transfer performance is reduced on the refrigerant side due to a shortage of refrigerant supply, or whether the heat transfer performance is reduced on the water side due to freezing. In other words, the outlet temperature of the fluid to be cooled cooled by the plate heat exchanger 5 is such that the temperature does not decrease even if a part of the passage inside the plate heat exchanger 5 is frozen. It does not mean that it is frozen. Therefore, it is possible to accurately grasp the presence or absence of freezing.

  Next, the control device 8 will be described.

  FIG. 1 is a configuration diagram schematically showing a functional configuration of the control device 8.

  That is, the control device 8 includes an input unit 10, an output unit 11, a data acquisition unit 12, a storage unit 13, a primary storage unit 14, a secondary storage unit 15, a calculation unit 16, and a comparison unit 17. The first comparison unit 18, the second comparison unit 19, the determination unit 20, the first determination unit 21, the second determination unit 22, the drive control unit 23, the compressor control unit 24, and the condenser control. Unit 25, expansion valve control unit 26, and refrigeration apparatus operation control unit 30 that performs overall control thereof.

  The input unit 10 is an interface that receives so-called externally input data. The externally input data is converted into data of a predetermined format by protocol conversion or the like, and the input data is transferred to the storage unit 13. Remember. For example, an initial setting value or the like input from outside (not shown) is converted into a predetermined format so that it can be used inside the control device. That is, when an initial set value is input in an operation start process described later, predetermined data is input via the input unit 10 that is an interface with the outside. Needless to say, data input by wire or wireless may be used.

  That is, at the time of data input by wireless communication, data communication may be performed by a wireless terminal (not shown) and the input unit 10.

  Further, the control device 8 may be connected indoors to a network such as a LAN, and wired or wireless communication may be performed.

  In addition, the input unit 10 may receive the detection results sent from the temperature detector 6 and the pressure detector 7 as needed and store them in the storage unit 13.

  The output unit 11 is an interface that transmits data to be output to the outside, converts the data to be output to a predetermined format by performing protocol conversion or the like, and transfers the data held in the storage unit to the outside Send it.

  Further, the output unit 11 may perform communication like the input unit 10 described above.

  Needless to say, the communication mode performed by the input unit 10 and the output unit 11 may be any communication mode such as satellite communication such as a satellite phone or cable television. May be.

  Thus, the refrigeration apparatus 1 of the present invention can communicate with a communication entity (not shown) located at a remote place via the control apparatus 8.

  It should be noted that protocol conversion and the like at the time of data transmission / reception can be easily understood by those skilled in the art, and a detailed description thereof will be omitted here.

  The data acquisition unit 12 acquires the refrigerant temperature and the refrigerant pressure detected by the temperature detector 6 and the pressure detector 7 via the data line 101 and the data line 102. After acquiring the data, the data acquisition unit 12 stores the acquired data in the storage unit 13. As will be described in detail later, it is assumed that the storage unit 13 includes a primary storage unit 14 and a secondary storage unit 15, which are used separately according to the data storage period.

  Further, as will be described later, when the data acquisition unit 12 searches for data for performing a predetermined calculation, the data acquisition unit 12 searches the data stored in the secondary storage unit 15 and stores the search result in the primary storage unit 14. Let As will be described later, the storage location of the search result is based on the primary storage unit 14 of the storage unit 13, but may be the secondary storage unit 15.

  Further, as will be described later, when the data acquisition unit 12 cannot acquire the data, the data acquisition unit 12 searches for another data stored in the storage unit and stores the search result in the primary storage unit 14. In this case as well, the storage location of the search result is based on the primary storage unit 14 of the storage unit 13, but may of course be the secondary storage unit 15.

  As described above, the storage unit 13 includes the primary storage unit 14 and the secondary storage unit 15. The primary storage unit 14 is a logical area for holding temporary data being processed. The primary storage unit 14 is mounted on a high-speed small-capacity memory such as a cache memory (not shown), for example. This speeds up the processing inside the control device 8. The secondary storage unit 15 is a logical area for storing processing results for a long period of time. The secondary storage unit 15 is mounted on, for example, a low-speed large-capacity memory such as a hard disk (not shown). Thereby, it becomes possible to store the processing content in the control apparatus 8 for a fixed period. As a result, for example, when investigating the operation status of the refrigeration apparatus for one month, it is possible to use a predetermined group of data stored in the secondary storage unit 15. Further, the mounting destination of the secondary storage unit 15 is not limited to the hard disk, and it is sufficient that data is stored for a long period of time as compared with the primary storage unit 14. Therefore, both the primary storage unit 14 and the secondary storage unit 15 may be mounted on a general semiconductor memory, for example, a flash memory.

  More specifically, the data received by the input unit 10 may be first stored in the area of the primary storage unit 14 and stored in the secondary storage unit 15 through a predetermined process. Further, for example, the data transmitted from the output unit 11 is such that the data stored in the secondary storage unit 15 is first copied to the primary storage unit 14 and then the copied data is converted into a predetermined format. May be converted and transmitted. For example, the data acquired by the data acquisition unit 12 may be temporarily stored in the primary storage unit 14 and then stored in the secondary storage unit 15 after a predetermined time has elapsed.

  In any case, the primary storage unit 14 is an area used for temporarily storing data for performing a predetermined process, and the secondary storage unit 15 stores a result of the predetermined process for a long time. It is an area used for this purpose.

  Next, the calculating part 16, the comparison part 17, the determination part 20, and the drive control part 23 are demonstrated based on a mutual relationship.

  The calculation unit 16 performs a predetermined calculation, the result is compared by the comparison unit 17, and the comparison result is determined by the determination unit 20. The refrigeration apparatus 1 is controlled by the drive control unit 23 according to the determination result. In short, the control unit 16, the comparison unit 17, and the determination unit 20 determine the control content of the refrigeration apparatus 1, and the drive control unit 23 controls the refrigeration apparatus 1 accordingly.

  The computing unit 16 calculates the refrigerant superheat degree by the control device 8 described above. Specifically, the calculation unit 16 calculates a saturated vapor temperature from the refrigerant pressure acquired by the data acquisition unit 12, and calculates a difference between the calculated saturated vapor temperature and the refrigerant temperature acquired by the data acquisition unit 12. Thus, the refrigerant superheat degree is obtained. Needless to say, the calculation unit 16 can execute not only the calculation of the refrigerant superheat degree, but also any calculation for determining parameters for controlling the refrigeration apparatus 1.

  The comparison unit 17 includes a first comparison unit 18 and a second comparison unit 19 and compares different contents. Specifically, the first comparison unit 18 compares the refrigerant pressure acquired by the data acquisition unit 12 with the pre-stored freezing abnormality set value, and the second comparison unit 19 is calculated by the calculation unit 16. The refrigerant superheat degree is compared with a predetermined superheat degree stored in advance. Note that the freezing abnormality set value here is equivalent to the freezing abnormality outlet temperature from the relationship between the suction pressure of the compressor 2 and the outlet temperature of the cooled medium of the plate heat exchanger 5. The suction pressure of the machine 2 is predetermined. More specifically, since the refrigerant R407C is abnormal if the pressure is less than 0.33 MPa, the freezing abnormality set value is 0.33 MPa. This value is obtained by a verification test. That is, it is a value obtained by a verification test for the refrigerant pressure of the compressor 2 corresponding to when the plate heat exchanger 5 reaches freezing. The predetermined degree of superheating here is a predetermined degree of superheat when the evaporation pressure is reduced and the degree of superheat is reduced when the plate heat exchanger 5 is abnormally frozen. More specifically, the predetermined superheat degree is a superheat degree controlled by the expansion valve 4 and is, for example, 10 ° C. In other words, the degree of superheat is controlled to 10 ° C. by the expansion valve 4. As a result, the low pressure state is not lowered. If the degree of superheat is lower than 10 ° C., for example, the plate heat exchanger 5 is sufficiently filled with the refrigerant. Therefore, it is not a low pressure drop due to a refrigerant side heat transfer performance drop. That is, this state is a low pressure drop due to a drop in water-side heat transfer performance. As a result, by referring to the predetermined degree of superheat determined here, the cause of the decrease in the suction pressure of the compressor 2 is the refrigerant side heat transfer performance deterioration due to the lack of refrigerant supply or due to freezing It is possible to distinguish whether the water-side heat transfer performance is reduced. Therefore, the presence or absence of freezing can be determined accurately.

  The determination unit 20 includes a first determination unit 21 and a second determination unit 22, and determines different contents. Specifically, the first determination unit 21 determines whether to reduce the capacity of the compressor or stop the operation of the refrigeration apparatus based on the comparison result of the second comparison unit 19. The second determination unit 22 determines whether or not to continue the process of reducing the capacity of the compressor.

  The drive control unit 23 includes a compressor control unit 24, a condenser control unit 25, and an expansion valve control unit 26, and performs different controls. Specifically, the compressor control unit 24 controls the driving of the electric motor of the compressor 2, for example, the capacity and the rotation speed. The condenser control unit 25 controls the driving of a fan motor installed in the condenser 3, that is, the fan of the condenser, for example, the rotational speed of the fan. The expansion valve control unit 26 controls the expansion valve 4, for example, the opening degree of the expansion valve 4. In short, the compressor control unit 24, the condenser control unit 25, and the expansion valve control unit 26 issue commands to the respective actuators according to the processing results of the calculation unit 16, the comparison unit 17, and the determination unit 20. Various controls of the compressor 2, the condenser 3, and the expansion valve 4 are performed.

  As a result, the control device 8 can perform a predetermined calculation based on the detection results of the temperature detector 6 and the pressure detector 7, thereby identifying a factor that reduces the suction pressure of the compressor 2. Further, the suction pressure of the compressor 2 can be regarded as substantially equivalent to the refrigerant pressure on the outlet side of the plate heat exchanger 5. Therefore, by performing a predetermined calculation based on the suction pressure of the compressor 2, it is possible to prevent the plate heat exchanger 5 from being damaged due to freezing, so that the refrigeration apparatus 1 can be operated with high efficiency.

  Next, the outline of the refrigeration apparatus operation control unit 30 will be described.

  The refrigeration apparatus operation control unit 30 performs overall control in the control apparatus 8. That is, the input unit 10, the output unit 11, the data acquisition unit 12, the calculation unit 16, the comparison unit 17, the determination unit 20, the drive control unit 23, and the like are appropriately controlled.

  The input unit 10, the output unit 11, the data acquisition unit 12, the calculation unit 16, the comparison unit 17, the first comparison unit 18, the second comparison unit 19, the determination unit 20, the first determination unit 21, and the control unit 8 described above. The second determination unit 22, the drive control unit 23, the compressor control unit 24, the condenser control unit 25, the expansion valve control unit 26, the refrigeration apparatus operation control unit 30 and the like are processed by, for example, a microcomputer.

  Various processes of the control device 8 can be updated as appropriate. For example, data communication is enabled by connecting an external terminal (not shown) and the control device 8 with a cable or the like, and the update stored in the external terminal in this state. A program or the like which is the processing content is transmitted to the control device 8, and the new processing content is overwritten. Thereby, it becomes possible to update the processing contents according to the situation as appropriate.

  In addition, various processes of the control device 8 may be stored in a semiconductor memory or the like. In this case, by replacing the semiconductor memory mounted in the control device 8 with another semiconductor memory storing update contents, The processing content may be updated. For example, the processing content may be updated using an SD memory card as a medium. Needless to say, in this case, the various processes stored in the mounted semiconductor memory may be overwritten, and the semiconductor memory may be re-installed to be updated.

  Various processes of the control device 8 may be configured as firmware. Even in this case, the processing content can be updated as appropriate.

  In addition, all the various processes of the control device 8 may be implemented by a logic circuit or the like.

  Anyway, the mounting method of the various processes of the control apparatus 8 is not limited, What is necessary is just to mount the control apparatus 8 and control the whole refrigeration apparatus 1.

  Next, on the premise of the configuration of the refrigeration apparatus 1 described above, by controlling the compressor 2 by distinguishing between the refrigerant side heat transfer performance decrease and the water side heat transfer performance decrease, which are the main parts of the present invention, Processing for operating the refrigeration apparatus 1 with high efficiency will be described using a flowchart.

  The flowchart described below is based on sequential processing, but the present invention is not limited to this. For example, each step may be processed in parallel, and a plurality of steps described in each flowchart may be simultaneously processed in parallel as a group of units. In any case, before and after the process is not limited by the following description, and the process may be appropriately performed in series or in parallel.

  FIG. 2 is a flowchart showing overall processing according to Embodiment 1 of the present invention. As shown in FIG. 2, the control device 8 of the present invention performs processing for starting the operation of the refrigeration apparatus 1 to determine whether or not the plate heat exchanger 5 is damaged due to freezing during normal operation. When the determination is made and the operation of the refrigeration apparatus 1 is stopped, the operation of the refrigeration apparatus 1 is terminated (S10 to S13). Specifically, an operation start process (S10), a normal operation process (S11), an operation stop command flag determination process (S12), and an operation end process (S13) are sequentially executed. Thereby, since the operation of the refrigeration apparatus 1 can be stopped before the plate heat exchanger 5 of the refrigeration apparatus 1 reaches freezing, the plate heat exchanger 5 is not damaged due to freezing during the operation of the refrigeration apparatus 1. Can be prevented. Therefore, the refrigeration apparatus 1 can be operated with high efficiency. In other words, although the operation stop command flag will be described later, in short, when the operation stop command flag is 1 (S12 YES), the operation termination process of the refrigeration apparatus is executed (S13), and when the operation stop flag is not 1 (S12 NO) ), Normal operation processing (S11) is executed.

  More specifically, the refrigeration apparatus operation control unit 30 performs overall control of operation start processing (S10), normal operation processing (S11), operation stop command flag determination processing (S12), and operation end processing (S13). . That is, the refrigeration apparatus operation control unit 30 grasps the progress of each process by constantly monitoring various flags described later, and shifts the process at an appropriate timing. In this way, the refrigeration apparatus operation control unit 30 executes the synchronization process of each process. As a result, it is possible to execute each process appropriately sequentially or in parallel.

  FIG. 3 is a flowchart showing details of the operation start process according to Embodiment 1 of the present invention. As shown in FIG. 3, the operation start process is on standby until an initial set value is input, and when an initial set value is input from the outside, a process according to the input form is executed (S20 to S25). ). Subsequently, various processes are performed to drive the refrigeration apparatus (S26 to S28).

  Specifically, first, the input unit 10 waits for an input from the outside (S20, S21). When there is an input (S21), the process proceeds to a process for determining the input mode at the time of input (S22).

  As a result of the input determination process (S22), the input unit 10 performs the input process by the external device when the input is from the external device (S23). Specifically, the external device is, for example, a handheld terminal. The handheld terminal is connected to the control device 8, for example, a connector (not shown) via a cable. When the control device 8 confirms the connection from the outside, the input unit 10 establishes communication between the input unit 10 and an input / output interface mounted inside the handheld terminal. Specifically, the input unit 10 determines a communication protocol with the handheld terminal, and enters a state where it can communicate with a communication module inside the handheld terminal. When mutual communication becomes possible, data input from the handheld terminal is sequentially received via the input unit 10, and the received data is temporarily stored in the primary storage unit 14. When the reception process is completed, the input unit 10 moves the received data stored in the primary storage unit 14 to the secondary storage unit 15 and stores it. At this time, the data transmitted from the handheld terminal may be data manually input by the human to the handheld terminal. Also good. The recording medium may be any medium, for example, miniSD (registered trademark). Furthermore, it goes without saying that scanner data, barcode data, RFID tags, etc. read by a handheld terminal may be used.

  As a result of the input determination process (S22), the input unit 10 performs the input process using the communication medium when the communication data is input (S24). Specifically, the input process using the communication medium includes, for example, Bluetooth (registered trademark), wireless LAN, optical communication, and the like. Also in this case, the input unit 10 establishes communication by a predetermined communication protocol so that the input unit 10 can receive communication data from the outside, and enters a state where mutual communication is possible.

  Here, the difference between the input processing by the external device (S23) and the input processing by the communication medium (S24) is that the input by the external device is accompanied by a direct physical connection with the control device 8 by a cable or the like. The input process by the communication medium is not the physical connection with the control device 8 by a cable or the like, but the input process by communication from a remote place is assumed. Therefore, the initial setting value can be set in the refrigeration apparatus 1 from a remote place, for example, by the input process (S24) using the communication medium. This makes it possible to set the initial setting value without going directly to the site. In addition, the initial setting value may be transmitted by e-mail or the like from the operator's mobile phone. In this case, the input unit reads the initial setting value from the mail sentence by a text analysis unit (not shown) and stores the initial setting value in the primary storage unit 14. The set value may be stored.

  As a result of the input determination processing (S22), the input unit 10 performs input processing by direct input when direct input to the refrigeration apparatus 1 is performed (S25). Specifically, if the control device 8 has an input button (not shown), the initial setting value may be directly input via the input button. At this time, when the input button is pressed, the input unit 10 generates a predetermined signal set in advance, and for example, an input corresponding to the number of times the input button is pressed is made. More specifically, a target outlet water temperature or the like of cold water is set by pressing a numeric button (not shown). The result is stored in the primary storage unit 14, and when an end button (not shown) is pressed, the data stored in the primary storage unit 14 is moved to the secondary storage unit 15, so that an initial setting value is obtained. Is stored. If the control device 8 has an operation unit such as a micro-type push button switch or a DIP switch (not shown), the setting operation of the initial setting value may be performed by using these. In this case, the input unit 10 executes a process as a direct input process (S25).

  The initial set values are the target outlet water temperature of cold water, the flow rates of the pumps of the heat source side device and the load side device, the cooling water inlet water temperature, the cold water inlet water temperature, and the like. The opening degree of the valve 4 is set. Note that details of setting the rotation speed of the compressor 2 and the opening of the expansion valve 4 are easily understood by those skilled in the art, and the details thereof are omitted here.

  Next, a process for driving the refrigeration apparatus is executed (S26). Specifically, the refrigeration apparatus operation control unit 30 issues a drive command to the drive control unit 23 so that the drive control unit 23 satisfies the initial set value based on the initial set value stored in the secondary storage unit 15. put out. More specifically, each actuator controls the compressor 2, the condenser 3, and the expansion valve 4, respectively. More specifically, a cooling water pump (not shown) is operated, water is passed through a condenser and the like, a cooling tower (not shown) is operated, a blower (not shown) of the plate heat exchanger 5 is operated, and an electric motor of the compressor 2 Will start. On the other hand, when stopping, the compressor 2 is stopped, the cooling water pump (not shown) is stopped, and the blower (not shown) of the plate heat exchanger 5 is stopped.

  Next, the refrigeration apparatus operation control unit 30 sets the compressor operation flag stored in the primary storage unit 14 to 1 (S27), and sets the operation stop flag stored in the primary storage unit to 0 ( S28).

  As a result of the above processing (S20 to S28) being performed, the refrigeration apparatus 1 starts operation.

  FIG. 4 is a flowchart showing details of normal operation processing according to Embodiment 1 of the present invention. As shown in FIG. 4, processing for determining whether to stop the refrigeration apparatus 1 executed during normal operation is executed based on the value of the compressor operation flag (S30 to S34).

  That is, if the compressor operation flag stored in the primary storage unit 14 is 1 (YES in S30), processing for determining whether to stop the refrigeration apparatus 1 is executed (S31 to S34). On the other hand, if the compressor operation flag is 0 (NO in S30), the normal operation process ends without executing the process of determining whether to stop the refrigeration apparatus 1.

  FIG. 5 is a flowchart showing details of the data acquisition processing according to Embodiment 1 of the present invention. As shown in FIG. 5, a process of measuring the refrigerant temperature and the refrigerant pressure and storing the results in the storage unit 13 is executed (S40 to S52).

  That is, when a preset predetermined interval has elapsed (S40 YES), processing for obtaining the refrigerant temperature and refrigerant pressure shown below is executed (S41 to S52). On the other hand, when the preset predetermined interval has not elapsed (NO in S40), the process waits until the predetermined interval elapses. The predetermined interval may be set when the initial setting value described above is input, or is stored in the secondary storage unit 15 as a default, and the secondary storage unit is started when the data acquisition process is started. The data stored in 15 may be copied to the primary storage unit 14. Further, the predetermined interval may be updated as appropriate during operation of the refrigeration apparatus 1. In this case, for example, when the use period of the refrigeration apparatus 1 is short, a relatively long interval is set, and when the use period is long, a relatively short interval is set, thereby performing data acquisition processing corresponding to the use history. Can be executed.

  Next, the refrigerant temperature is measured by the temperature detector 6 (S41), and the refrigerant pressure is measured by the pressure detector 7 (S42). Subsequently, data acquisition of the measured refrigerant temperature is executed (S43). Specifically, the refrigerant temperature transmitted from the temperature detector 6 and stored is read from the secondary storage unit 15. At this time, when the refrigerant temperature data cannot be acquired (NO in S44), the refrigerant temperature flag stored in the primary storage unit 14 is set to 0 (S45). On the other hand, when the refrigerant temperature data can be acquired (S44 YES), the refrigerant temperature flag is set to 1 (S46), and the refrigerant temperature data is stored in the secondary storage unit 15 (S47).

  Next, the refrigerant temperature flag is also copied to the secondary storage unit 15 at a predetermined timing. In this way, when it is confirmed that the refrigerant temperature flag stored in the secondary storage unit 15 remains 0 for a certain period, it is estimated that some trouble has occurred in the temperature detector 6 and its surroundings. be able to.

  Next, data acquisition processing of the measured refrigerant pressure is executed (S48). Specifically, the refrigerant pressure transmitted from the pressure detector 7 and stored is read from the secondary storage unit 15. At this time, when the refrigerant pressure cannot be acquired (S49 NO), the refrigerant pressure flag stored in the primary storage unit 14 is set to 0 (S50). On the other hand, when the refrigerant pressure data can be acquired (S49 YES), the refrigerant pressure flag is set to 1 (S51), and the refrigerant pressure data is stored in the secondary storage unit 15 as the refrigerant pressure first data (S52). .

  Next, the refrigerant pressure flag is also copied to the secondary storage unit 15 at a predetermined timing. In this way, when it is confirmed that the refrigerant pressure flag stored in the secondary storage unit 15 continues to be 0 for a certain period, it is estimated that some trouble has occurred in the pressure detector 7 and its surroundings. be able to.

  FIG. 6 is a flowchart showing details of the arithmetic processing according to Embodiment 1 of the present invention. As shown in FIG. 6, a process for calculating the degree of refrigerant superheat based on the refrigerant temperature and the refrigerant pressure is executed (S60 to S70).

  That is, first, the latest refrigerant temperature data is searched from the secondary storage unit (S60). The term “nearest” here refers to the most recently stored data among the refrigerant temperature data stored in the secondary storage unit 15. For example, since the data acquisition process (S31) is a process that is always performed while the normal operation process is being executed, the refrigerant temperature data is continuously stored in the secondary storage unit 15 sequentially. In this state, a process of searching for the most recently stored data from among a plurality is performed.

  Next, when the refrigerant temperature flag of the retrieved data is 1 (S61 YES), the refrigerant temperature data is directly read from the secondary storage unit 15 into the primary storage unit 14 (S62), and the latest refrigerant pressure first data is searched. (S63). On the other hand, when the refrigerant temperature flag is 0 (NO in S61), the secondary storage unit 15 is searched for data with the refrigerant temperature flag being 1 (S64). At the time of search, past data is sequentially searched from the latest data with reference to the update time of the refrigerant temperature flag. When there is data with the refrigerant temperature flag being 1 (YES at S65), the refrigerant temperature data is read into the primary storage unit 14, and the process of searching for the latest refrigerant pressure first data is sequentially executed (S62, S63). In contrast, when there is no data with the refrigerant temperature flag being 1 (NO in S65), the refrigerant temperature dummy data stored in advance is read from the secondary storage unit 15 into the primary storage unit 14 (S66), and the latest refrigerant is stored. A process of searching for the pressure first data is executed (S63).

  As a result, even when the latest refrigerant temperature data cannot be acquired, data that is relatively close to the update time is searched first, so that data close to the state at the time of the arithmetic processing can be used. Even when the refrigerant temperature data itself cannot be obtained, the refrigerant superheat degree described later can be calculated by using the preliminarily stored refrigerant temperature dummy data.

  Next, when the refrigerant pressure flag of the retrieved data is 1 (YES in S67), the refrigerant pressure data is directly read from the secondary storage unit 15 into the primary storage unit 14 (S68), and the refrigerant superheat degree is calculated (S69), The calculation result is stored in the secondary storage unit 15 (S70). On the other hand, when the refrigerant pressure flag is 0 (NO in S67), data for the refrigerant pressure flag being 1 is searched from the secondary storage unit 15 (S71). At the time of search, past data is sequentially searched from the latest data with reference to the update time of the refrigerant pressure flag. When there is data with the refrigerant pressure flag being 1 (YES in S72), the first refrigerant pressure data is read into the primary storage unit 14, the refrigerant superheat degree is calculated, and the calculation result is stored in the secondary storage unit 15 (S68, S69, S70). On the other hand, when there is no data in which the refrigerant pressure flag is 1 (NO in S72), the refrigerant pressure dummy data stored in advance is read from the secondary storage unit 15 into the primary storage unit 14 (S73), and the degree of refrigerant superheat Is calculated (S69), and the calculation result is stored in the secondary storage unit 15 (S70).

  As a result, even if the latest refrigerant pressure data cannot be acquired, data that is relatively close to the update time is searched first, so that data close to the state at the time of the arithmetic processing can be used. Even when the refrigerant pressure data itself cannot be acquired, the refrigerant superheat degree can be calculated by using the refrigerant pressure dummy data stored in advance.

  Here, when calculating the refrigerant superheat degree (S69), the calculation unit 16 calculates the refrigerant superheat degree by using the refrigerant temperature and refrigerant pressure first data stored in the primary storage unit. Specifically, the calculating unit 16 calculates the saturated steam temperature from the first refrigerant pressure data, and calculates the difference between the calculated saturated steam temperature and the refrigerant temperature, thereby obtaining the refrigerant superheat degree.

  FIG. 7 is a flowchart showing details of the comparison processing according to Embodiment 1 of the present invention. As shown in FIG. 7, the measured refrigerant pressure is compared with the freezing abnormality set value, and subsequently, a process of comparing the calculated refrigerant superheat degree with a predetermined superheat degree is executed (S100 to S108). .

  That is, each comparison process is executed by the comparison unit 17. Specifically, the first refrigerant pressure data read during the calculation process is read again from the primary storage unit 14 as the refrigerant pressure (S100), and the freezing abnormality set value is read from the secondary storage unit 15 (S101). Subsequently, the first comparison unit 18 compares the refrigerant pressure with the freezing abnormality set value.

  Next, when the refrigerant pressure is smaller than the freezing abnormality set value (YES in S102), the refrigerant superheat degree is read from the secondary storage unit 15 (S103), and the preset predetermined superheat degree is read from the secondary storage unit 15 (S104). ).

  Subsequently, a comparison process between the refrigerant superheat degree and the predetermined superheat degree is executed by the second comparison unit 19, and the superheat degree flag is set to 1 when a predetermined condition is satisfied. Specifically, when the refrigerant superheat degree is larger than the predetermined superheat degree (S105 YES), the superheat degree flag stored in the primary storage unit 14 is set to 1 (S106), and the compressor operation flag is set to 1. (S107), the comparison process is terminated. On the other hand, when the refrigerant superheat degree is equal to or lower than the predetermined superheat degree (S105 NO), the compressor operation flag is set to 0 (S108), and the comparison process is terminated. When the refrigerant pressure is equal to or higher than the freezing abnormality set value (NO in S102), the compressor operation flag is set to 1 (S109), and the comparison process is terminated.

  As a result, it is possible to identify whether the factor that reduces the suction pressure of the compressor is a decrease in refrigerant-side heat transfer performance due to insufficient refrigerant supply or a decrease in water-side heat transfer performance due to freezing. Therefore, it is not necessary to perform a process of stopping the refrigeration apparatus when the refrigerant side heat transfer performance is reduced, and thus it is possible to operate the refrigeration apparatus with high efficiency. That is, conventionally, when the refrigerant pressure is smaller than the freezing abnormality set value, the operation of the refrigeration apparatus 1 is uniformly stopped. On the other hand, in the present invention, even in this case, when the refrigerant superheat degree is larger than the predetermined superheat degree, the operation of the refrigeration apparatus 1 is not stopped, and the process of reducing the capacity of the compressor 2 described later is performed. Continue driving.

  FIG. 8 is a flowchart showing details of the determination processing according to Embodiment 1 of the present invention. As shown in FIG. 8, a process of stopping the refrigeration apparatus 1 or reducing the capacity of the compressor 2 is executed according to the value of the superheat degree flag and the value of the compressor operation flag ( S110 to S114).

  That is, when the superheat degree flag is not 1 by the first determination unit 21 (S110 NO), the process branches depending on the value of the compressor operation flag. That is, when the value of the compressor operation flag is 1 (S111 YES), the operation stop command flag is set to 0 (S112), and when the value of the compressor operation flag is not 1 (S111 NO), the operation stop command flag is 1 (S113). On the other hand, when the superheat degree flag is 1 (YES in S110), the first determination unit 21 executes a process for reducing the capacity of the compressor 2 (S114).

  As a result, since the process of not stopping the operation of the refrigeration apparatus when the refrigerant-side heat transfer performance is reduced, the operation can be continued when the refrigerant heat transfer performance is reduced due to the delay in following the expansion valve control. Therefore, even when the suction pressure of the compressor 2 is reduced, the operation is not considered to be regarded as a freezing abnormality uniformly. Thereby, a highly efficient refrigeration apparatus can be operated. In other words, in this case, when the superheat degree flag is 1, the lowering factor of the refrigerant pressure, that is, the suction pressure of the compressor 2 is the lowering of the refrigerant side heat transfer performance. More specifically, when refrigerant pressure <freezing abnormality set value (S102 YES) and refrigerant superheat> predetermined superheat (S105 NO), the water-side heat transfer performance is reduced. On the other hand, when refrigerant pressure <freezing abnormality set value (S102 YES) and refrigerant superheat degree> predetermined superheat degree (S105 YES), the refrigerant side heat transfer performance is reduced.

  FIG. 9 is a flowchart showing details of the compressor capacity reduction processing according to Embodiment 1 of the present invention. As shown in FIG. 9, while adjusting the capacity of the compressor 2, the refrigerant pressure is observed, and when the refrigerant pressure satisfies a predetermined condition, a process for ending the reduction of the compressor capacity is executed ( S200 to S208). Specifically, the capacity is reduced until the refrigerant pressure in the low pressure state rises to 0.33 MPa. Therefore, as will be described later, whether or not to continue the compressor capacity reduction process is determined by comparison with the freezing abnormality set value.

  That is, a process for adjusting the capacity of the compressor 2 is executed (S200), and the pressure of the refrigerant is measured by the pressure detector 7 (S201). Subsequently, refrigerant pressure data acquisition processing is executed (S202). When acquisition of the refrigerant pressure data is not possible (NO in S203), the process of adjusting the capacity of the compressor 2 is executed again, the refrigerant pressure is measured, and the refrigerant pressure data is acquired (S200 to S202). On the other hand, when the refrigerant pressure data can be acquired (S203 YES), the following processing is executed (S204 to S208).

  That is, the acquired refrigerant pressure data is stored in the secondary storage unit 15 as the refrigerant pressure second data (S204). The difference from the first refrigerant pressure data described above is that the second refrigerant pressure data continues to be acquired during the compressor capacity reduction as a parameter for determining the end of the compressor capacity reduction process.

  Here, the reason why the second refrigerant pressure data is stored in the secondary storage unit 15 is that it is used as maintenance data.

  Next, the freezing abnormality set value is read from the secondary storage unit 15 to the primary storage unit 14 (S205), and is read from the secondary storage unit 15 to the primary storage unit 14 as the refrigerant pressure for comparing the refrigerant pressure second data ( S206). Subsequently, the refrigerant pressure is compared with the freezing abnormality set value, and when a predetermined condition is satisfied, the compressor capacity adjustment process is executed again, and the comparison between the refrigerant pressure and the freezing abnormality set value is executed again ( S200 to S207).

  Specifically, when the second determination unit 22 determines that the refrigerant pressure is smaller than the freezing abnormality set value (NO in S207), the above processing (S200 to S207) is executed. On the other hand, when the second determination unit 22 determines that the refrigerant pressure is equal to or higher than the freezing abnormality set value (YES in S207), the superheat degree flag is set to 0 (S208) and stored as described above. Is done.

  As a result, when the refrigerant side heat transfer performance is reduced, the capacity of the compressor 2 can be reduced. As a result, the operation of the refrigeration apparatus 1 can be continued. Therefore, even when the suction pressure of the compressor 2 is reduced, the operation is not considered to be regarded as a freezing abnormality uniformly. Thereby, a highly efficient refrigeration apparatus can be operated.

  FIG. 10 is a flowchart showing details of the compressor capacity adjustment processing according to Embodiment 1 of the present invention. As shown in FIG. 10, by calculating the low-pressure pressure that does not cause freezing and the duration of the low-pressure, a process for determining the adjustment amount of the compressor capacity and reducing the compressor capacity is executed (S400 to S400). S411).

  That is, the low pressure that does not lead to freezing is calculated (S400), and the calculation result is stored in the secondary storage unit 15 (S401). Subsequently, the low pressure continuation time at the low pressure that does not cause freezing is calculated (S402), and the calculation result is stored in the secondary storage unit 15 (S403).

  Next, the low pressure value and the constant pressure duration time are read from the secondary storage unit 15 (S404, S405), respectively, and the first refrigerant pressure data is read from the secondary storage unit 15 (S406).

  In addition, as a calculation method of the low pressure value that does not lead to freezing and the low pressure duration, for example, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2003-287291), it is obtained by estimating a predicted value using a characteristic curve. To do.

  Next, the value of the counter is set to 0 (S407), and then it is determined whether the value of the counter is the low pressure duration time. Specifically, when the counter matches the low pressure duration (SS408 YES), the process for adjusting the compressor capacity ends. On the other hand, when the counter does not coincide with the low pressure continuation time (NO in S408), the counter value is incremented by a predetermined value (S409). The reason for incrementing by a predetermined value here is that increments may be made, for example, by +1, or may be incremented at a different interval. Specifically, for example, it may be incremented by 0.1 or may be incremented by 10. In any case, any predetermined value may be used as long as the value of the counter is updated.

  Next, an actuator or the like is driven, and a compressor capacity reduction process is executed (S410). Subsequently, the refrigerant pressure first data is compared with the low pressure value, and the compressor capacity reduction process is continued until a predetermined condition is satisfied.

  Specifically, when the refrigerant pressure first data is smaller than the low pressure value (YES in S411), the counter value is confirmed, the counter is updated, and the compressor capacity reduction process is executed (S408 to S411). On the other hand, when the refrigerant pressure first data is equal to or higher than the low pressure value (NO in S411), the predetermined process ends.

  As a result, the compressor capacity can be reduced only when necessary. As a result, the operation of the refrigeration apparatus 1 can be continued. Therefore, even when the suction pressure of the compressor 2 is reduced, the operation is not considered to be regarded as a freezing abnormality uniformly. Thereby, a highly efficient refrigeration apparatus can be operated.

  As described above, according to the first embodiment, the operation of the compressor 2 can be stopped when the suction pressure of the compressor 2 is reduced due to freezing. As a result, the plate-type heat exchanger can be prevented from being damaged due to freezing, so that the refrigeration apparatus can be operated with high efficiency. In other words, it is possible to efficiently prevent puncture of the plate heat exchanger 5 and a decrease in the refrigerating capacity due to freezing of water or brine inside the plate heat exchanger 5 due to a decrease in evaporation pressure.

Embodiment 2. FIG.
In the second embodiment, items that are not particularly described are the same as those in the first embodiment, and the same functions and configurations are described using the same reference numerals.

  FIG. 11 is a flowchart showing details of the compressor capacity reduction processing according to Embodiment 2 of the present invention. As shown in FIG. 11, while adjusting the capacity of the compressor 2, the refrigerant pressure is observed, and when the refrigerant pressure satisfies a predetermined condition, a process for ending the reduction of the compressor capacity is executed ( S300 to S310). The difference from the first embodiment is that the compressor capacity adjustment time is restricted and the compressor capacity reduction rate is changed after the restriction time elapses (S308, S309).

  That is, in the first embodiment, when the refrigerant pressure is smaller than the freezing abnormality set value, the compressor capacity adjustment process is executed again. On the other hand, in the second embodiment, when a predetermined time has elapsed since the compressor capacity reduction start (YES in S308), the capacity reduction rate of the compressor 2 is changed (S309), and the compressor capacity adjustment process is executed. On the other hand, when the predetermined time has not elapsed since the start of the compressor capacity reduction (NO in S308), the compressor capacity adjustment process is executed again as it is.

  As a result, even if the compressor capacity is continuously reduced at the same rate, the reduction rate of the compressor capacity is changed after a predetermined time even when the refrigerant pressure does not exceed the abnormal freezing setting value. ing. Therefore, if the reduction rate is changed so as to further reduce the capacity of the compressor 2, even in such a case, it is possible to eliminate the shortage of refrigerant supply. As a result, the refrigerant pressure can be made higher than the freezing abnormality set value, so that the operation of the refrigeration apparatus 1 can be continued. In other words, it is possible to efficiently prevent puncture of the plate heat exchanger 5 and a decrease in the refrigerating capacity due to freezing of water or brine inside the plate heat exchanger 5 due to a decrease in evaporation pressure.

  DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus, 1a Refrigeration cycle apparatus, 2 Compressor, 3 Condenser, 4 Expansion valve, 5 Plate type heat exchanger, 6 Temperature detector, 7 Pressure detector, 8 Control apparatus, 10 Input part, 11 Output part, 12 data acquisition units, 13 storage units, 14 primary storage units, 15 secondary storage units, 16 calculation units, 17 comparison units, 18 first comparison units, 19 second comparison units, 20 determination units, 21 first determination units, 22 second determination unit, 23 drive control unit, 24 compressor control unit, 25 condenser control unit, 26 expansion valve control unit, 30 refrigeration apparatus operation control unit, 101, 102 data line.

Claims (2)

A refrigeration cycle apparatus that forms a refrigeration cycle in which a compressor, a condenser, an expansion valve, and a plate heat exchanger are sequentially connected by refrigerant piping;
Refrigerant temperature detecting means for detecting the refrigerant temperature on the suction side of the compressor;
Refrigerant pressure detection means for detecting refrigerant pressure on the suction side of the compressor;
Based on the refrigerant pressure detected by the refrigerant pressure detection means and the refrigerant temperature detected by the refrigerant temperature detection means, the refrigerant superheat degree of the compressor is calculated, and based on the refrigerant pressure and the refrigerant superheat degree. Control means for controlling the capacity of the compressor .
The control means is configured such that the refrigerant pressure is smaller than a freezing abnormality set value corresponding to a case where the outlet temperature of the plate heat exchanger is regarded as freezing abnormality, and the refrigerant superheat degree is the plate heat exchanger. Is larger than the degree of superheat at the time of freezing abnormality, the capacity of the compressor is reduced, and it is considered that the heat transfer performance on the refrigerant side of the plate heat exchanger is deteriorated, and the refrigerant pressure is The refrigeration apparatus is characterized in that when the refrigerant superheat degree is smaller than a set value and the refrigerant superheat degree is equal to or less than the superheat degree, the operation of the compressor is stopped . When the refrigerant pressure is smaller than the freezing abnormality set value after reducing the capacity of the compressor, the control means is configured to reduce the compression when a predetermined time elapses after the capacity of the compressor is reduced. The refrigerating apparatus according to claim 1 , wherein the capacity of the machine is further reduced.

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