JP5518431B2 - Refrigeration equipment - Google Patents

Description

  In the present invention, a plurality of refrigerators each equipped with a variable capacity compressor are connected to a use side device by piping, and the control device sets the refrigerating capability required according to the heat load of the use side device. The present invention relates to a refrigeration apparatus that controls operation by assigning to a variable compressor.

  In general, use side devices such as multiple showcases are arranged in parallel, and multiple refrigerators containing compressors and heat exchangers are connected in parallel to the inter-unit piping connected to each showcase. A so-called multi refrigerator is known (for example, see Patent Document 1). In addition to showcases, in a multi-type air conditioner, etc., a plurality of indoor units are arranged in parallel, and a compressor, an outdoor heat exchanger, etc. are incorporated in the inter-unit piping connected to each indoor unit. A plurality of outdoor units are connected in parallel.

  In this case, when connecting a plurality of outdoor units in parallel, combining either a variable capacity compressor or a constant capacity compressor, for example, when the cooling load is less than the capacity of the constant capacity compressor The capacity variable compressor is operated, and above that, the constant capacity compressor and the variable capacity compressor are operated simultaneously, so that the operation capacity of the outdoor unit can be adjusted according to the cooling load.

JP 2002-206812 A

  In the above, ON / OFF control of the operation of a plurality of compressors according to the cooling load is performed. In this control, the priority order of the compressors to be operated is determined in advance, and the cooling load is determined. If control is performed to increase the number of operating units according to the increase, a specific compressor is preferentially used. If it does so, only the said compressor will have the total operation time longer than other compressors, will deteriorate, and there exists a problem which the lifetime as the whole apparatus becomes short. Therefore, the durability of the entire apparatus is improved by leveling the total operation time of each compressor.

  In this case, the control device constantly monitors the total operation time of each compressor, sets the operation rank of the compressor with the shortest total operation time high, and sets the operation rank of the compressor with the short total operation time low. To do. And based on this order, the operation of each compressor is combined and controlled according to the cooling load.

  However, in such control, since the cooling capacity is distributed based on the total operation time of each compressor, the operation is not performed in consideration of the efficient range (rotation speed) in each compressor. In general, the output horsepower of an inverter compressor changes approximately in proportion to the operating frequency of the compressor, but the coefficient of performance COP does not become a constant value throughout the operating frequency, but a specific operating frequency (output). There is a tendency to be lower in the peak.

  In the present invention, in consideration of the coefficient of performance COP of each compressor, the operation time of each compressor is leveled, and the operation in the range where the operation efficiency is high is realized, so that the overall efficient operation is realized. Provided is a refrigeration apparatus capable of

In order to solve the above-described problems, the refrigeration apparatus of the present invention connects a plurality of refrigerators each equipped with a variable-capacity compressor to a user side device, and uses a control device to add heat to the user side device. The operation is controlled by allocating the required refrigeration capacity to each variable capacity compressor, and the controller is short based on the total operation time of each capacity variable compressor. The higher the priority, the more variable capacity compressors are operated, and even if the required refrigeration capacity is a value that can be covered by the highest priority variable capacity compressor, the next highest priority By allocating to variable capacity compressors as well, if the refrigeration capacity shared by each variable capacity compressor falls within the high operating efficiency of both variable capacity compressors, the required refrigeration capacity is set for each capacity. with driving by assigning the variable displacement compressor, necessary Refrigeration capacity is allocated after a predetermined waiting time has elapsed since the refrigeration capacity is changed, and if the required degree of change in refrigeration capacity is greater than the predetermined value, the waiting time has elapsed Without refrigeration capacity allocation .

  According to the invention of claim 2, in the above, when the required refrigeration capacity is a value within a high operating efficiency range of the variable capacity compressor having the highest priority, the control apparatus It is characterized by not allocating to high capacity variable compressors.

  The invention of claim 3 is a case where the refrigerator is equipped with a constant capacity type compressor in addition to the variable capacity compressor in the above inventions, and the priority of the variable capacity compressor of the refrigerator is the highest. When the priority of a high-capacity compressor is lower than the other variable-capacity compressors, the control device does not operate the constant-capacity compressor, and the other compressor's variable-capacity compression is operated. The refrigeration capacity is allocated to the machine.

The invention of claim 4 is the case of the invention of claim 1 or claim 2 in which the refrigerator is equipped with a constant capacity type compressor in addition to the variable capacity type compressor, and the capacity variable type of the refrigerator. When the priority of the compressor is the lowest and the priority of the fixed capacity compressor is the highest, the control device can control the refrigerating capacity within the range where the operating efficiency is high in the other variable capacity compressors of the plurality of refrigerators. When the allocation is possible, the refrigeration capacity is allocated by the other plurality of variable capacity compressors .

  According to the present invention, a plurality of refrigerators each equipped with a variable capacity compressor are connected to a use side device by piping, and the control device provides the refrigerating capacity required according to the heat load of the use side device. In the refrigeration system that controls the operation by assigning to each capacity variable compressor, the control device sets the priority to a higher priority as the total operation time is shorter based on the total operation time of each capacity variable compressor. Operate the variable compressor and assign it to the next highest priority variable compressor even if the required refrigeration capacity can be covered by the highest priority variable compressor. If the refrigeration capacity shared by each variable capacity compressor falls within the high operating efficiency of both variable capacity compressors, the required refrigeration capacity is allocated to each variable capacity compressor for operation. So the operating efficiency of each compressor is high In other words, considering the coefficient of performance COP, the operation time of each compressor is leveled, and the operation in the range where the operation efficiency is high can be realized. The power consumption can be reduced.

In addition, the control device avoids the inconvenience that the compressor is frequently started and stopped by executing the allocation of the refrigeration capacity after a predetermined waiting time has elapsed since the required refrigeration capacity has changed. Reduction of power consumption can be realized.

In this case, if the required degree of change in the refrigeration capacity is greater than the predetermined value, the controller will improve the shortage of refrigeration capacity at an early stage by allocating the refrigeration capacity without waiting for the standby time to elapse. And a stable cooling operation can be realized.

  According to the invention of claim 2, in addition to the above, the control device, when the required refrigeration capacity is a value within a range where the operating efficiency of the variable capacity compressor with the highest priority is high, By not allocating to variable capacity compressors with high priority, it is possible to preferentially operate compressors with a short total operation time, and more reliably the operation time of each compressor. Leveling can be realized.

  According to the invention of claim 3, in addition to the above-mentioned inventions, the refrigerator is equipped with a constant capacity compressor in addition to the variable capacity compressor, and the variable capacity compressor of the refrigerator When the priority is the highest and the priority of the fixed capacity compressor is lower than the variable capacity compressor of the other refrigerator, the control device does not operate the fixed capacity compressor, By allocating refrigeration capacity to variable capacity compressors, it is possible to preferentially operate compressors with a short total operation time, and more reliably achieve leveling of the operation time of each compressor. it can.

  According to the invention of claim 4, in the invention of claim 1 or claim 2, the refrigerator is equipped with a constant capacity type compressor in addition to the variable capacity type compressor, and the capacity of the refrigerator When the priority of the variable compressor is the lowest, and the priority of the constant capacity compressor is the highest, the control device can perform refrigeration within a range where the operation efficiency is high in the variable capacity compressors of other chillers. When capacity can be allocated, the refrigeration capacity is allocated by the other multiple capacity variable compressors, resulting in fluctuations in the heat load of the equipment on the user side. And the allocation of the refrigeration capacity between the compressor and the variable capacity compressor is changed, and the inconvenience that these compressors are frequently started and stopped can be avoided.

As a result, it is possible to perform efficient operation as a whole by operating the variable capacity compressor in a range where the operation efficiency is high while realizing the leveling of the operation time of each compressor. Can be planned .

It is a refrigerant circuit figure of the refrigerating device of the example to which the present invention is applied. It is the schematic which shows a control system. It is a flowchart regarding the operation control of each compressor. It is a flowchart regarding the operation control of each compressor. It is a figure which shows the relationship of the output with respect to the operating frequency of a compressor. It is a figure which shows the relationship of COP with respect to the operating frequency of a compressor. It is a figure which shows allocation of the freezing capacity of each compressor as an example. It is a refrigerant circuit figure of the freezing apparatus as another Example. It is a figure which shows allocation of the freezing capacity of each compressor as an example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus 1 according to an embodiment to which the present invention is applied. The refrigeration apparatus 1 according to the embodiment realizes cooling of a plurality of showcases (use side devices, such as a refrigerator case and a refrigerator case) as a cooling storage facility installed in a store such as a supermarket. It is.

  In the refrigeration apparatus 1, a refrigerant circuit 2 is piped between a plurality of refrigerators, in this embodiment, as an example, refrigerators 3, 4, 5 and each showcase installed in the store. . The refrigerant circuit 2 includes a compressor 3A of the refrigerator 3, a compressor 4A of the refrigerator 4, and a compressor 5A of the refrigerator 5, and in this embodiment, the compressors 3A to 3A constituting the refrigerators 3 to 5 are provided. 5A is connected in parallel, a condenser 6, an oil separator (not shown), a receiver tank 7, etc., a plurality of evaporators 10 installed in each showcase to cool the interior of each of these cabinets, A liquid electromagnetic valve 11... Provided corresponding to each evaporator 10, an expansion valve 12... As a pressure reducing device, and an accumulator 13 are sequentially connected in an annular manner. Each evaporator 10 is connected in parallel, and each evaporator 10 is provided with a temperature sensor. In addition, although the condenser 6, the oil separator, the receiver tank 7, the accumulator 13, etc. may be provided for each refrigerator 3 thru | or 5, it shall be used in common with each refrigerator in a present Example.

  With this configuration, when the compressor 3A, 4A, 5A or a combination thereof is operated as will be described in detail later, the high-temperature and high-pressure gas refrigerant discharged from the discharge side of each compressor 3A, 4A, 5A is The heat is dissipated in the condenser 6, condensed and liquefied, and temporarily stored in the receiver tank 7. And the refrigerant | coolant which came out of this receiver tank 7 reaches the expansion valve 12 corresponding to each through each liquid electromagnetic valve 11, and is pressure-reduced there. The refrigerant decompressed by the expansion valve 12 flows into the evaporator 10 installed in the duct of the showcase and evaporates, taking heat from the surroundings and exerting a cooling action.

  Then, the inside of the showcase is cooled to a predetermined temperature by circulating the cool air exchanged with the evaporator 10 through the blower (not shown). The refrigerant (mixed state of evaporated gas refrigerant and non-evaporated liquid refrigerant) exiting from these evaporators 10 enters the accumulator 13 where it is separated into gas and liquid, and then the compressors 3A, 4A, Return to 5A.

  Each liquid electromagnetic valve 11 is opened and closed based on the temperature inside the showcase, and controls the supply of refrigerant to each evaporator 10. As a result, the operation of each of the compressors 3A, 4A, 5A is stopped when all the liquid electromagnetic valves 11 of the plurality of showcases connected to the refrigeration apparatus 1 are closed, and the operation is started when any liquid electromagnetic valve is opened. Control to be performed is performed.

  In the present embodiment, the compressors 3A, 4A, and 5A all employ inverter compressors as variable capacity compressors, and the output horsepower of each of the compressors 3A to 5A is the same. Assuming 6 horsepower.

  And as shown in FIG. 2, each refrigerator 3, 4, 5 is provided with main control part 3C, 4C, 5C comprised with a general purpose microcomputer. In the present embodiment, the refrigerator 4 is a master unit that performs overall control of the refrigerator 1, and the refrigerators 3 and 5 are slave units. The refrigerator 4 constituting the master unit has a system control unit 4D constituting the control device of the present invention.

  Each of the main control units 3C, 4C, and 5C has configuration information such as the type and number of built-in compressors, and information on the operation status thereof, for example, information such as the current rotation speed and total accumulated operation time. It controls the rotational speed of the built-in variable capacity compressor. In the present embodiment, the main control units 3C, 4C, and 5C can change the cooling capacity in units of 0.1 horsepower within the range of 0 to 6.0 horsepower.

  And main control part 3C, 4C, 5C transmits the configuration information of these compressors, and the information regarding an operating condition to system control part 4D of refrigerator 4 which constitutes a main unit. The system control unit 4D includes a means for detecting the thermal load of each showcase that is a use side device, in this embodiment, a pressure for detecting the low pressure side pressure values (input pressures) of the compressors 3A, 4A, and 5A. A sensor, a temperature sensor provided in each evaporator 10, or a control device for a user-side device (not shown) to which these pressure sensors and temperature sensors are connected is connected. Thereby, the system control unit 4D of the refrigerator 4 constituting the master unit can acquire the heat load of the use side device, and is necessary based on the heat load acquired from the use side device. Refrigeration capacity is acquired in units of 0.1 horsepower, and as will be described in detail later, distribution of cooling capacity to the compressors 3A, 4A, 5A constituting each refrigerator is acquired, and the distribution result of the cooling capacity is obtained for each It transmits to main control part 3C, 4C, 5C.

  Next, operation control of the compressors 3A, 4A, and 5A will be described with reference to the flowcharts of FIGS. In this embodiment, the system control unit 4D of the parent device performs operation control every predetermined control period, for example, every 30 seconds. First, in step S1, it is determined whether or not the predetermined control period has been reached. If it has been reached, the process proceeds to step S2. In step S2, the system control unit 4D determines whether or not the required refrigeration capacity acquired from the usage-side device is 0 or more. If the required refrigeration capacity input from the use side device is not 0 or more, the process returns to step S1.

  When the required refrigeration capacity is 0 or more, the process proceeds to step S3, and the system control unit 4D determines whether or not the required refrigeration capacity acquired from the use side device has increased from zero. . When it is up, the system control unit 4D acquires the total operation accumulated time from the main control units 3C, 4C, and 5C constituting the refrigerators 3, 4, and 5 in step S4. Here, it is determined whether or not the required refrigeration capacity has increased from 0. However, the present invention is not limited to this, and it may be determined whether or not it has changed. The operation priority of the compressor is determined from the acquired total operation accumulated time. That is, the shorter the total operation integration time (total operation time), the higher the priority, and the longer the total operation integration time, the lower the priority. Note that after determining whether or not the required refrigeration capacity has increased (or changed) from 0 in step S3, the priority order is determined in step S4. Next, the refrigeration capacity is determined. Until the value becomes 0, the operation priority of the compressor is not changed.

  Thereafter, the system control unit 4D proceeds to step S5, and whether or not the refrigerating capacity required based on the heat load acquired from the use side device has increased (or changed) by a predetermined value, for example, 2.0 horsepower or more. Judging. The predetermined value is a reference value for determining whether or not the required degree of change in the refrigerating capacity is large, and the value is not limited to this. Then, when the degree of change in the refrigerating capacity required is smaller than the predetermined value, the process proceeds to the flowchart (I) as shown in FIG. 4, and when the degree of change is large, the process proceeds to step S6.

  When the degree of change in the refrigerating capacity required is smaller than the predetermined value and the process proceeds to step S7 in FIG. 4, the system control unit 4D determines in step S7 that the refrigerating capacity required from the use side device is described later. It is determined whether or not the number of compressors to be operated has been increased (or changed) to the refrigeration capacity that must be changed. If not (or changed), the process proceeds to step S8.

  In step S8, the system control unit 4D determines the horsepower distribution of the cooling capacity to the compressors 3A, 4A, and 5A based on the first rule, and transmits the result to the main control units 3C, 4C, and 5C. Based on this, the main control units 3C, 4C, and 5C execute operation control of the corresponding compressors 3A, 4A, and 5A.

  Here, the first rule will be described. First, the system control unit 4D determines from the information transmitted from the main control units 3C, 4C, and 5C, the number of compressors constituting the refrigeration apparatus 1, the type of compressors configured, and in this case, all the compressors. Confirm that the compressor is a variable capacity compressor. Further, the priority order of each compressor determined in step S4 is confirmed.

  Here, in the variable capacity compressors 3A, 4A, and 5A (inverter compressors as an example) employed in the present embodiment, as shown in FIG. 5, the output horsepower of the compressor changes substantially in proportion to the operating frequency. . On the other hand, as shown in FIG. 6, the coefficient of performance COP of the compressor calculated from the value obtained by dividing the output horsepower by the input power does not become a constant value over the entire operating frequency, but a specific operating frequency, That is, the specific output horsepower tends to decrease to a peak. Although this change tendency of COP is strictly different depending on the compressor and the drive circuit, there is no big difference in the tendency, and it is input that the compressor is operated at a high operating frequency of COP, that is, in the range of output horsepower. Efficient operation with respect to electric power can be realized, and power consumption can be reduced.

  The variable capacity compressors 3A, 4A, and 5A employed in this embodiment can achieve high COP operation in the range of 2 to 4 horsepower with a peak of 3 horsepower. In this embodiment, the range of 2 to 4 horsepower is given as an example of the high COP range. However, the range of the efficient COP differs depending on the compressor, and it is measured before being set in advance. Based on this, control as in this embodiment is performed.

  Based on the above, in this embodiment, the system control unit 4D distributes from a high priority compressor to 2 horsepower, and thereafter 12 horsepower (in this embodiment, 3 compressors are provided, so 3 X Refrigerating capacity is allocated to each compressor up to 4 horsepower which is the maximum value of the range of efficient COP.

  FIG. 7 shows that the refrigerating capacity required from the use side device is 3.0 horsepower, the compressor 3A is first in priority order of the compressors determined from the total operation accumulated time of each compressor, and the compressor 4A. Is the second and the compressor 5A is the third.

  In this case, the required refrigeration capacity is 3.0 hp, which is within the range of refrigeration capacity (2.0-4.0 hp) that can be covered by a high COP range in one compressor. . Therefore, 3.0 hp of all the refrigeration capacities required only for the compressor 3A having the shortest total operation accumulated time and the highest priority is allocated, and the other compressors 4A and 5A are not used.

  Until the required refrigeration capacity gradually increases to 4.0 horsepower, a single compressor can cover all of the required refrigeration capacity in the high COP range. Operate only one high-order compressor.

  If the required refrigeration capacity further increases to 4.1 horsepower, the range that can cover all the required refrigeration capacity in a high COP range in one compressor. Therefore, the refrigeration capacity is allocated with 2.1 hp for the high priority compressor (eg, 3A) and 2.0 hp for the next highest priority compressor (eg, 4A).

  In this embodiment, since the refrigeration capacity is allocated by 0.1 horsepower, when the required refrigeration capacity reaches 4.2 horsepower, the compressor with the highest priority (for example, 3A) is set to 2 .1 horsepower, the next highest priority compressor (eg 4A) is 2.1 horsepower, and thereafter the refrigeration capacity is evenly allocated (allocated) until the required refrigeration capacity is 8.0 horsepower. .

  When the required refrigeration capacity exceeds 8.1 horsepower, at least one of the two compressors deviates from the range that can be covered by the high COP range. Run all compressors. In this case, in order to distribute the refrigerating capacity evenly, the compressor with the highest priority (for example, 3A) is 2.7 horsepower, the second highest compressor (for example, 4A) is 2.7 horsepower, and is the third highest. Allocate a compressor (eg 5A) to 2.7 hp. Thereafter, until the required refrigeration capacity reaches 12.0 horsepower, the refrigeration capacity is sequentially and evenly distributed according to the priority order.

  And when the refrigerating capacity exceeding the maximum horsepower that can be operated in the high COP range is requested from the use side device, only the high priority compressor (for example, 3A) exceeds the high COP range. Allocate up to maximum horsepower (for example, maximum horsepower of 6.0 horsepower).

  Based on such a first rule, the system control unit 4D allocates the refrigerating capacity of each compressor, and the main control units 3C, 4C, 5C of the respective refrigerating machines 3, 4, 5 are based on the compressors 3A. Operation is performed by changing the operation frequency of 4A and 5A. Thereafter, the process returns to step S1 (II).

  Thereby, based on the total operation time of each capacity variable compressor 3A, 4A, 5A, the system control unit 4D increases the priority and operates each capacity variable compressor as the total operation time is shorter. At the same time, even if the required refrigeration capacity is a value that can be covered by the highest-priority variable-capacity compressor, each variable-variable compression can be assigned to the next highest-priority variable-capacity compressor. When the refrigeration capacity shared by the machine falls within the high operating efficiency range of both capacity variable compressors, the required refrigeration capacity is allocated to each capacity variable compressor for operation.

  Therefore, in consideration of the coefficient of operation COP in consideration of the high operating efficiency range of each compressor, the operation time of each compressor is leveled and the operation in the high operating efficiency range is realized. Efficient operation can be performed and power consumption can be reduced.

  Further, in this embodiment, the system control unit 4D has a value within a range (4.0 horsepower in this embodiment) in which the required efficiency of the variable capacity compressor having the highest priority is high. If it is possible to operate with high operating efficiency even with only a compressor with a short total operating time, by not allocating to the next variable capacity compressor of the highest priority Only the compressor can be preferentially operated, and the operation time of each compressor can be leveled more reliably.

  On the other hand, in step S7 of FIG. 4 described above, the system control unit 4D increases (or changes) the refrigeration capacity required from the use side device to the refrigeration capacity that requires changing the number of compressors to be operated. If it is determined, the process proceeds to step S9.

  In step S9, it is determined whether or not a predetermined standby time, 2 minutes as an example in this embodiment, has elapsed since the required refrigeration capacity has changed to such an extent that the number of compressors to be operated must be changed. . If not, the process proceeds to step S11, and the horsepower distribution of the cooling capacity to each compressor 3A, 4A, 5A is determined based on the second rule, and the result is assigned to each main controller 3C, 4C, Based on this, the main control units 3C, 4C, and 5C execute operation control of the corresponding compressors 3A, 4A, and 5A.

  Here, the second rule will be described. Similar to the first rule, first, the system control unit 4D first determines the number of compressors constituting the refrigeration apparatus 1 and the type of compressors constituting from the information transmitted from the main control units 3C, 4C, 5C. In this case, it is confirmed that all the compressors are variable capacity compressors. Further, the priority order of each compressor determined in step S4 is confirmed.

  Then, similarly to the first rule, the system control unit 4D distributes from a high-priority compressor to 2 horsepower, and thereafter 12 horsepower (since three compressors are provided in this embodiment, Consider assigning refrigeration capacity to each compressor up to 3 units x 4 horsepower, which is the maximum value of the efficient COP range.

  Here, when allocating the refrigeration capacity of the compressor, it is necessary to allocate a new refrigeration capacity to the compressor that was not in operation in the previous allocation of refrigeration capacity, or the compression that was in operation If it is necessary to allocate the refrigeration capacity to zero, the allocation is not performed.

  As an example, in the previous control, the refrigerating capacity required from the use side device is 4.0 horsepower, and only one compressor having a high priority is operated. In this control, if the refrigeration capacity required from the equipment on the user side is 4.1 horsepower, as described above, all of the required refrigeration capacity is set to a high COP in one compressor. Therefore, the compressor with the highest priority (eg 3A) is 2.1 horsepower, and the compressor with the next highest priority (eg 4A) is 2.0 horsepower. Allocate capacity. In such a case, since the number of operating compressors increases (changes) from the previous control, the compression is not performed in step S11 until the predetermined standby time in step S9 elapses without performing the allocation. Although it deviates from the range that can be covered by the high COP range of the machine, it is all of the refrigerating capacity required from the use side equipment to one compressor (for example, 3A) that has been operated so far 4. Allocate 1 horsepower.

  Based on such a second rule, the system control unit 4D allocates the refrigerating capacity of each compressor, and the main control units 3C, 4C, and 5C of the respective refrigerating units 3, 4, and 5 based on this, each compressor 3A. Operation is performed by changing the operation frequency of 4A and 5A. Thereafter, the process returns to step S1 (II).

  On the other hand, if it is determined in step S9 that the predetermined standby time has elapsed, the system control unit 4D proceeds to step S10 and determines the refrigerating capacity of each compressor based on the first rule as described above. Make the allocation. That is, in the above example, when the refrigerating capacity required from the use side equipment is 4.1 horsepower, and the refrigerating capacity changes to some extent by changing the number of compressors to be operated, the high priority compression is performed. The refrigeration capacity is allocated with 2.1 hp for the machine (eg 3A) and 2.0 hp for the next highest priority compressor (eg 4A).

  Based on such a first rule, the system control unit 4D allocates the refrigerating capacity of each compressor, and the main control units 3C, 4C, 5C of the respective refrigerating machines 3, 4, 5 are based on the compressors 3A. Operation is performed by changing the operation frequency of 4A and 5A. Thereafter, the process returns to step S1 (II).

  As a result, the system control unit 4D allocates the refrigeration capacity that causes a change in the number of operating compressors based on the first rule after a predetermined waiting time has elapsed since the required refrigeration capacity has changed. By executing the above, it is possible to avoid inconvenience that the compressor is frequently started and stopped, and to realize power consumption reduction.

  Further, when it is determined in step S5 in FIG. 3 that the refrigerating capacity required based on the heat load acquired from the use side device is increased (or changed) by a predetermined value, for example, 2.0 horsepower or more. In step S6, the system control unit 4D proceeds to step S6 and immediately determines whether or not the required refrigeration capacity has been increased (or changed) as in step S7. Based on the first rule, the horsepower distribution of the cooling capacity to each of the compressors 3A, 4A, and 5A is determined, and the result is transmitted to each main control unit 3C, 4C, and 5C, and based on this, each main control unit 3C 4C and 5C execute operation control of the corresponding compressors 3A, 4A, and 5A. Thereafter, the process returns to step S1 (II).

  As a result, when the required degree of change in the refrigeration capacity is greater than the predetermined value, the system control unit 4D performs the refrigeration capacity allocation without waiting for the standby time to elapse, thereby quickly lacking the refrigeration capacity. Can be improved, and a stable cooling operation can be realized.

  Next, a refrigeration apparatus 20 as another embodiment will be described with reference to the refrigerant circuit diagram of FIG. The refrigeration apparatus 20 has substantially the same configuration as the refrigeration apparatus 1 as described above, and the refrigerator 3 is equipped with a variable capacity compressor 3A and a constant capacity compressor 3B similar to the above. It is. The constant capacity compressor 3B is connected in parallel with the variable capacity compressor 3A, and is ON / OFF controlled by the main controller 3C of the refrigerator 3. In the present embodiment, as an example, it is assumed that the output horsepower of the constant capacity compressor 3B is 5 horsepower.

  Also in this case, operation control of each compressor 3A, 3B, 4A, 5A is performed according to the flowchart of FIG.3 and FIG.4 similarly to the said Example. Here, the first rule employed in steps S6, S8, and S10 of FIGS. 3 and 4 will be described.

  In this case, the system control unit 4D determines from the information transmitted from the main control units 3C, 4C, and 5C, the number of compressors constituting the refrigeration apparatus 1, the type of compressors configured, Confirm that there are three variable capacity compressors and one constant capacity compressor. Further, the priority order of each compressor determined in step S4 is confirmed.

  The system control unit 4D determines that the priority order of the variable capacity compressors 3A, 4A, and 5A of each refrigerator is the highest when there is no higher priority than the variable capacity compressors. When the priority of the high-capacity compressor 3B is lower than the variable-capacity compressors of other refrigerators, the variable-capacity compressor having a high priority without operating the constant-capacity compressor 3B. To 2 horsepower, and thereafter 12 horsepower as the required refrigeration capacity increases (in this example, 3 variable capacity type compressors are provided, so 3 x efficient COP range) Allocate refrigeration capacity evenly to each variable capacity compressor until the maximum value of 4 horsepower).

  Thereby, even when the constant capacity type compressor 3B is mounted, the compressor having a short total operation time can be preferentially operated, and the operation time of each compressor can be leveled more reliably. Can be realized.

  In this case, when the refrigerating capacity required from the use side device exceeds 12 horsepower, that is, the maximum value of the efficient COP range of each capacity variable compressor is 4 horsepower × the number of refrigerating units. When capacity is required, the system control unit 4D allocates a constant refrigeration capacity, in this case, 5.0 horsepower, to the constant capacity compressor 3B. Since a part of the required refrigerating capacity is allocated to the constant capacity compressor 3B, the remaining required refrigerating capacity (7.11 horsepower if 12.1) is from the viewpoint of energy saving. Rather than operating all three variable capacity compressors 3A, 4A, and 5A that have been operating up to now, priority is given to the two priority variable capacity compressors (for example, 3A and 4A). Allocate evenly (in this case, 3.6 horsepower for the variable-capacity compressor 3A having the first priority and 3.5 horsepower for the variable-capacity compressor 4A having the second priority).

  On the other hand, when the priority of the constant capacity compressor 3B is higher than the priorities of the variable capacity compressors 3A, 4A, and 5A of the other refrigerators, a plurality of variable capacity compressions with lower priorities. When it is possible to allocate the refrigeration capacity within a high operating efficiency (COP) range by the machine, the refrigeration capacity is allocated by the other plurality of variable capacity compressors as shown in FIG.

  That is, in FIG. 8, the refrigeration capacity required from the use side device is 7.0 hp, and the compressor priority order determined by the total operation accumulated time of each compressor is the constant capacity type compressor 3B. The case where the number 1, the variable capacity compressor 4A is the second, the variable capacity compressor 5A is the third, and the variable capacity compressor 3A is the fourth is shown. Here, in order to facilitate the understanding of the allocation, it is assumed that allocation of 1.0 horsepower is performed instead of allocation of 0.1 horsepower as in the above embodiment.

  In this case, the required refrigeration capacity is 7.0 hp. If 5.0 hp of this refrigeration capacity is allocated to the constant capacity type compressor 3B, the variable capacity compressor 4A having the next highest priority. 2.0 horsepower will be allocated. However, if the required refrigeration capacity is reduced as it is, the compressor whose capacity can be made variable is only the compressor 4A. If the refrigeration capacity allocated to the compressor 4A is reduced, the compressor is high. It will deviate from the range of refrigeration capacity that can be covered by the COP range.

  Therefore, in order to follow the change in the required refrigeration capacity by operating the variable capacity compressor in a stable and high COP range, first, a plurality of variable capacities are operated without operating the constant capacity compressor 3B. Allocate evenly within the range of refrigeration capacity that each type compressor can cover in the high COP range. In this case, 4.0 horsepower is allocated to the capacity variable compressor 4A having the next highest priority, and the remaining 3.0 horsepower is allocated to the capacity variable compressor 5A having the next highest priority.

  Thus, even when the compressors constituting each refrigerator are equipped with a constant capacity compressor in addition to the variable capacity compressor, the priority of the variable capacity compressor of the refrigerator is the lowest. When the priority of the fixed capacity compressor is the highest, the system control unit 4D determines that the refrigeration capacity can be allocated within the range where the operation efficiency is high with the variable capacity compressors of the other plurality of refrigerators. By allocating the refrigeration capacity using the other variable capacity compressors, the heat load of the equipment on the user side fluctuates, so that the constant capacity compressor and variable capacity compressor can be used in a short period of time. The inconvenience that the allocation of the refrigeration capacity is changed and the compressors are frequently started and stopped can be avoided.

  As a result, it is possible to perform efficient operation as a whole by operating the variable capacity compressor in a range where the operation efficiency is high while realizing the leveling of the operation time of each compressor. Can be planned.

  Also in the embodiment in which the constant capacity type compressor is mounted, in step S7 in FIG. 4, the required refrigeration capacity is increased to the refrigeration capacity in which the type or number of compressors to be operated must be changed (or For example, the priority of the variable capacity compressor 3A is the first, and the priority of the constant capacity compressor 3B is the second, and the required refrigeration capacity is 8.0 hp. , First, 4.0 horsepower is allocated to the variable capacity compressor 3A, and 4.0 horsepower is allocated to the other variable capacity compressor. Until the predetermined waiting time elapses in step S9, the allocation is not changed from the variable capacity compressor 4A to the fixed capacity compressor 3B immediately, but the capacity is changed until the waiting time elapses. Even if the refrigeration capacity deviating from the high COP range of the variable compressor is allocated, the allocation is maintained. Then, after the standby time has elapsed, the process proceeds to step S10, in which 5.0 horsepower is allocated to the constant capacity compressor 3B, and the remaining refrigeration capacity 3.0 horsepower is allocated to the variable capacity compressor 5A having a high priority. .

  As a result, it is possible to avoid inconvenience due to frequent start / stop due to a change in the refrigerating capacity of the constant capacity compressor 3B.

  In each of the above embodiments, a plurality of use-side devices such as showcases are arranged in parallel, and a plurality of refrigeration units incorporating compressors and heat exchangers are installed in the inter-unit piping connected to each showcase. Although a so-called multi-refrigeration machine formed by connecting machines in parallel is described as an example, the present invention is not limited to this, and a plurality of indoor units are arranged in parallel, and each indoor unit The same effect can be obtained by adopting a so-called multi-type air conditioner configured by connecting a plurality of outdoor units containing a compressor and an outdoor heat exchanger in parallel to the inter-unit piping connected to be able to. In this case, the refrigerator in the said Example is comprised by the outdoor unit, and a utilization side apparatus (showcase) will be comprised by an indoor unit.

DESCRIPTION OF SYMBOLS 1,20 Refrigeration apparatus 2 Refrigerant circuit 3, 4, 5 Refrigerator 3A, 4A, 5A Variable capacity compressor 3B Constant capacity compressor 3C, 4C, 5C Main control part 4D System control part 6 Condenser 10 Evaporator 11 Liquid solenoid valve 12 Expansion valve

Claims (4)

A plurality of refrigerators each equipped with a variable capacity compressor are connected to the use side equipment by piping, and the control device changes the refrigerating capacity required according to the heat load of the use side equipment to each of the variable capacity types. In a refrigeration system that controls operation by assigning to a compressor,
The control device, based on the total operating time of each capacity variable compressor, the higher the priority, the higher the priority, the more variable capacity compressor is operated ,
Even if the required refrigeration capacity is a value that can be covered by the variable-capacity compressor having the highest priority, it is also allocated to the variable-capacity compressor having the next highest priority, so that each variable capacity type When the refrigeration capacity shared by the compressor falls within a high operating efficiency range of both capacity variable compressors, the required refrigeration capacity is allocated to each capacity variable compressor and operated .
After a predetermined waiting time has elapsed since the required refrigeration capacity has changed, the allocation of the refrigeration capacity is executed, and when the degree of change in the required refrigeration capacity is greater than a predetermined value, The refrigeration apparatus , wherein the refrigeration capacity is allocated without waiting for the elapse of the waiting time .   When the required refrigeration capacity is a value within a range of high operating efficiency of the variable capacity compressor having the highest priority, the control apparatus sets the variable capacity compressor having the next highest priority. 2. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is not allocated to the refrigeration apparatus.   When the refrigerator is equipped with a constant capacity compressor in addition to the variable capacity compressor, the priority of the variable capacity compressor of the refrigerator is the highest, and the priority of the constant capacity compressor Is lower than other variable capacity compressors of the refrigerator, the control device allocates the freezing capacity to the variable capacity compressors of the other refrigerator without operating the constant capacity compressor. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is performed. In the case where the refrigerator is equipped with a constant capacity compressor in addition to the variable capacity compressor, the priority of the variable capacity compressor of the refrigerator is the lowest, and the priority of the constant capacity compressor When the control device is capable of allocating the refrigeration capacity within the range where the operation efficiency is high with the other variable capacity compressors of the plurality of refrigerators, the other plurality of capacity variable types The refrigeration apparatus according to claim 1 or 2, wherein refrigeration capacity is allocated by a compressor.

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