JP2012007824A - Method and device for deciding the number of refrigerating machines to be operated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for deciding the number of refrigerating machines to be operated, with which the number of refrigerating machines to be operated can be decided, while reducing a burden when control of the refrigerating machines in a refrigerating machine system is performed.SOLUTION: The refrigerating machine system 1 includes a first refrigerating machine 10 and a second refrigerating machine 20. When it is decided whether one refrigerating machine is operated or two refrigerating machines are operated, out of these two refrigerating machines 10, 20, the optimum number decision line JL to be the reference of decision of the number of refrigerators in which an operation result becomes relatively large is preliminarily generated. Then, the number of machines to be operated out of the refrigerating machines 10, 20 is decided depending on whether the operation state of the refrigerating machine exceeds the optimum number decision line JL or not.

Description

  The present invention relates to a method and apparatus for determining the number of operating refrigerators for determining the number of operating refrigerators capable of operating a plurality of units.

  Conventionally, in a refrigerator system using a plurality of refrigerators, control for adjusting the number of operating refrigerators has been performed in order to increase COP (Coefficient Of Performance). Conventionally, as a method for determining the number of operating refrigerators when performing such control, in addition to COPs in a single refrigerator, cold water pumps and cooling water pumps included in the refrigerator system, and auxiliary equipment such as cooling towers A cold heat source system that determines the number of operating refrigerators while improving the COP in consideration of the above is disclosed (see, for example, Patent Document 1). In this cold heat source system, using the characteristics related to the cold heat source machine load, the cold water pump, the cooling water pump, the cooling tower fan, etc., a parameter used for a predetermined calculation formula is created, and based on the calculation result using this parameter, This is to control the number of operating cold heat source units and the output.

JP 2008-134013 A

  However, in the cold heat source system disclosed in the above-mentioned Patent Document 1, the parameters are determined and the calculation using the calculation formula is performed each time when the operation control of the cold heat source machine is performed. For this reason, there is a problem that the calculation must be performed every time the control is performed, and the burden for performing the control is increased.

  Accordingly, an object of the present invention is to provide a method and apparatus for determining the number of operating refrigerators that can determine the number of operating refrigerators while reducing the burden when controlling the refrigerator in the refrigerator system. There is.

  The method for determining the number of operating refrigerators according to the present invention that solves the above problem is to determine the operating number of refrigerators for determining the operating number of the plurality of refrigerators when performing air conditioning using a plurality of refrigerators. A method of generating an operation state map, which is a map having an optimum number judgment line as a criterion for judging the number of refrigerators whose operation results are relatively large, and determining whether the operation state of the refrigerator is an optimum number The operation number of the plurality of refrigerators is determined depending on whether or not the line is exceeded.

  In the method for determining the number of operating refrigerators according to the present invention, the operating number of the plurality of refrigerators is determined depending on whether the operating state of the refrigerator exceeds the optimum number determination line. For this reason, it is possible to determine the number of refrigerators to be operated while suppressing the calculation by the calculation formula. Therefore, it is possible to determine the number of operating refrigerators while reducing the burden when controlling the refrigerator in the refrigerator system. In addition, the operation state in the present invention refers to a state expressed by using one or more parameters such as production heat quantity, operation results, energy consumption, cooling water temperature, and cooling water flow rate during operation of the refrigerator system. The operating results in the present invention may be a COP of a refrigerator alone, or a synthetic COP that combines the COP of a refrigerator and the energy consumed by auxiliary equipment such as a cooling water pump, a cooling tower fan, and a cooling water pump. It can also be.

  Here, the operation state map may be an optimum state determination operation state map in which the horizontal axis represents the load factor with respect to the capacity of one refrigerator and the vertical axis represents the cooling water temperature of the refrigerator.

  When operating a refrigerator, data such as the amount of heat produced by the refrigerator and the cooling water temperature of the refrigerator are usually acquired in many cases. For this reason, the optimum number judgment line is a line formed by the optimum number judgment operation state map in which the horizontal axis represents the load factor with respect to the capacity of one refrigerator and the vertical axis represents the cooling water temperature of the refrigerator. Thus, it is possible to reduce the calculation load when determining the number of operating units.

  The optimum number judgment line is the cooling water when the first number of refrigerators are operated in the optimum number judgment line generating operation state map with the load factor relative to the capacity of one refrigerator as the horizontal axis and the operation result as the vertical axis. A line formed by connecting the points at the same temperature between the graph for each temperature and the graph for each cooling water temperature when the second number of refrigerators are operated on the operation state map for determining the optimum number of units. It can be set as the mode currently performed.

  Here, the optimal number determination line is a graph for each cooling water temperature when the first number of refrigerators are operated in the operation number map for generating the optimal number determination line, and a cooling water temperature when the second number of refrigerators is operated. It is a line formed by connecting points obtained by converting the intersections at the same temperature with each graph on the operation state map for determining the optimum number. For this reason, the calculation load at the time of generating the optimal number determination line can be reduced, and the optimal number determination line can be easily generated.

  Furthermore, when the number of operating refrigerators is switched, after the number of operating units is switched, the optimum number judgment line is moved in the direction in which the number of operating units is switched when the operating results are relatively smaller than before switching. It can be set as an aspect.

  In the method for determining the number of operating refrigerators according to the present invention, after the operation number is switched, the optimum number judgment line is moved in the direction in which the operation number is switched when the operation result is relatively smaller than before the switching. I am letting. For this reason, even when an error occurs in the optimum number determination line, the error can be corrected automatically with high accuracy.

  In addition, when it is determined that the number of operating units is to be switched, the point corresponding to the coolant temperature when the operating number is switched on the optimal unit determination line is moved in the direction in which the operating unit is switched, and the operation on the optimal unit determination line is performed. As the distance from the cooling water temperature when the number of units is switched, the value for moving the optimum number determination line can be reduced.

  In this way, by moving the optimum unit judgment line smaller as the distance from the operating results when the number of units operated on the optimum unit judgment line is switched, the most necessary part of the optimum unit judgment line is increased. It can be corrected. For this reason, the optimum number determination line can be corrected so as to be close to the actual optimum number determination line.

  Furthermore, when moving the optimal number determination line, the amount of movement of the optimal number determination line can be adjusted according to the amount of change in the operating results when the number of operating numbers on the optimal number determination line is switched.

  In this way, by adjusting the amount of movement of the optimal number judgment line according to the amount of change in the operating results when the number of operating numbers on the optimum number judgment line is switched, it is corrected to be close to the actual optimum number judgment line can do.

  Moreover, it can be set as the aspect which sets the switching delay range which is a range which delays switching of an operating number, after the driving | running state of a refrigerator exceeds the optimal number determination line with respect to the optimal number determination line.

  In this way, by setting the switching delay range on the optimum number determination line, it is possible to prevent the number of operating units from being switched excessively.

  Further, the switching delay range may be a predetermined non-switching range set in the optimum number determination line.

  Thus, the non-switching range for the optimum number determination line can be set as the switching delay range in the optimum number determination line. In addition, the non-switching range in the present invention is a range that is set when the operation state is a parameter, and is a range in which the number of operating refrigerators is not switched.

  Further, the switching delay range may be an aspect in which the energy saving reduction after exceeding the optimum number judgment line is within a predetermined value.

  Thus, by determining the switching delay range based on the energy saving performance reduction, it is possible to prevent excessive switching of the number of operating units and not to impair the energy saving performance.

  At this time, the predetermined value may be any numerical value from 1% to 10%.

  As a decrease in energy saving, it is preferable to allow within a range of 1% to 10%.

  Furthermore, it can be set as the aspect in which the predetermined value is adjustable.

  As described above, since it is desired to adjust the energy saving performance according to the operating conditions, etc., the predetermined value corresponding to the reduced energy saving performance can be adjusted, so that the switching of the number of operating units can be more suitably prevented. In addition, the energy saving performance can be prevented from being impaired.

  On the other hand, the present invention that has solved the above-described problems is a computer-readable computer that records a program for determining the number of operating refrigerators for causing the computer to execute the method for determining the number of operating refrigerators or a program for determining the number of operating refrigerators. It is a recording medium.

  The apparatus for determining the number of operating refrigerators according to the present invention that has solved the above problems is the operation of the refrigerator that determines the operating number of the plurality of refrigerators when performing air conditioning using the plurality of refrigerators. An operation state map storage means for storing an operation state map that is a map including an optimum number determination line that is a determination criterion for the number of refrigerators for which the operation results generated in advance are relatively large; And an operating number determining means for determining the operating number of the plurality of refrigerators depending on whether or not the operating state of the refrigerator exceeds the optimum number judgment line.

  Further, the operating state map is an apparatus for determining the number of operating units of the refrigerator, which is an operating state map for determining the optimum number with the horizontal axis representing the load factor relative to the capacity of one refrigerator and the vertical axis representing the cooling water temperature of the refrigerator. You can also.

  According to the method and apparatus for determining the number of operating refrigerators according to the present invention, it is possible to determine the operating number of refrigerators while reducing the burden of controlling the refrigerator in the refrigerator system.

It is a circuit diagram of the refrigerator system concerning a 1st embodiment. It is a block block diagram of a control apparatus. It is a figure which shows the driving | running state map in 1st Embodiment. It is a flowchart which shows the production | generation procedure of the optimal number determination line. (A) is a graph showing a COP curve when one refrigerator is operated, (b) is a graph showing a COP curve when two refrigerators are operated, and (c) is (a) and ( It is the graph which piled up b). It is a flowchart which shows the determination procedure of the operating number of refrigerators. It is a figure which shows the driving | running state map containing the optimal number determination line in 2nd Embodiment. It is a flowchart which shows the procedure which produces | generates a correction optimal number-of-devices determination line. (A) and (b) are graphs for explaining the reference points and comparison points used when the non-switching range is generated in the corrected optimum number judgment line by enlarging the vicinity of the intersection of the first COP curve and the second COP curve. . It is a block block diagram of the control apparatus which concerns on 3rd Embodiment. It is a flowchart which shows the process sequence of correction of the optimal number determination line which concerns on 3rd Embodiment. It is a graph which shows the 1st COP curve and the 2nd COP curve which were calculated | required on calculation, and the optimal number determination line. (A) is a graph which shows a 1st COP curve and a 2nd COP curve, (b) is the principal part enlarged view. It is a figure which shows each numerical relationship of a 1st COP curve and a 2nd COP curve. It is a figure which shows the state which corrected the optimal number determination line. It is a figure which shows each numerical relationship of the 1st COP curve and the 2nd COP curve at the time of delaying switching of the number of operation.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description may be omitted.

  First, a first embodiment of the present invention will be described. FIG. 1 is a circuit diagram of a refrigerator system according to the first embodiment of the present invention, and FIG. 2 is a block configuration diagram of a control device. As shown in FIG. 1, the refrigerator system 1 includes a first refrigerator 10 and a second refrigerator 20. A first cooling tower 12 is connected to the first refrigerator 10 via a first cooling water pipe 11. A second cooling tower 22 is connected to the second refrigerator 20 via a second cooling water pipe 21.

  Both the first refrigerator 10 and the second refrigerator 20 are inverter turbo refrigerators. Cooling water is circulated and supplied to the first refrigerator 10 from the first cooling tower 12 through the first cooling water pipe 11. Further, cooling water is circulated and supplied to the second refrigerator 20 from the second cooling tower 22 via the second cooling water pipe 21.

  Furthermore, a first air conditioner 31 and a second air conditioner 32 are connected to the first refrigerator 10 via a first cold water pipe 13. Similarly, a first air conditioner 31 and a second air conditioner 32 are connected to the second refrigerator 20 via a second cold water pipe 23. Cold water is circulated and supplied to the first air conditioner 31 and the second air conditioner 32 from the first refrigerator 10 and the second refrigerator 20 through the first cold water pipe 13 and the second cold water pipe 23, respectively.

  Further, a chilled water header 33 is interposed on the outlet side of the refrigerators 10 and 20 in the chilled water pipes 13 and 23. Similarly, a cold water return header 34 is interposed on the inlet side of the refrigerators 10 and 20 in the cold water pipes 13 and 23. The cold water return header 33 is provided with a cold water return header flow meter 33A shown in FIG. 2, and the cold water return header 34 is provided with a cold water return header flow meter 34A. The cold water forward header flow meter 33 </ b> A detects the flow rate of cold water in the cold water forward header 33. The cold water return header flow meter 34 </ b> A detects the flow rate of cold water in the cold water return header 34.

  Further, a first cooling water thermometer 14 is provided in the vicinity of the inlet side of the first refrigerator 10 in the first cooling water pipe 11, and the inlet side of the second refrigerator 20 in the second cooling water pipe 21. A second cooling water thermometer 24 is provided in the vicinity position. The first cooling water thermometer 14 measures the water temperature of the cooling water at the inlet of the first refrigerator 10, and the second cooling water thermometer 24 is the inlet of the second refrigerator 20 in the second cooling water pipe 21. The water temperature of the cooling water is measured.

  The first cooling water pipe 11 is provided with a first cooling water pump 15, and the second cooling water pipe 21 is provided with a second cooling water pump 25. By operating the first cooling water pump 15, the cooling water is supplied from the first cooling tower 12 to the first refrigerator 10 through the first cooling water pipe 11. Similarly, by operating the second cooling water pump 25, the cooling water is supplied from the second cooling tower 22 to the second refrigerator 20 via the second cooling water pipe 21.

  On the other hand, the cold water return thermometer 16 is provided in the cold water return header 33, and the cold water return thermometer 26 is provided in the cold water return header 34. The cold water flow thermometer 16 measures the temperature of cold water passing through the cold water flow header 33, and the cold water return thermometer 26 measures the temperature of cold water passing through the cold water return header 34.

  A first cold water pump 17 is provided in the first cold water pipe 13 between the cold water return header 34 and the first refrigerator 10, and a first cold water pump 17 is provided between the cold water return header 34 and the second refrigerator 20. The second cold water pipe 23 is provided with a second cold water pump 27. By operating the first cold water pump 17, cold water is supplied from the first refrigerator 10 to the air conditioners 31 and 32 via the first cold water pipe 13. Similarly, by operating the second cold water pump 27, cold water is supplied from the second refrigerator 20 to the air conditioners 31 and 32 via the second cold water pipe 23.

  Furthermore, the refrigerator system 1 includes a control device 40. The control device 40 is electrically connected to the refrigerators 10 and 20, the cooling towers 12 and 22, and the cooling water pumps 15 and 25, respectively. Further, the cooling water thermometers 14 and 24, the cold water thermometers 16 and 26, and the header flow meters 33A and 34A are electrically connected to the control device 40, respectively.

  The control device 40 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an I / O port, and the like, and manages the number of operating refrigerators 10 and 20. As shown in FIG. 2, the control device 40 includes a production heat quantity calculation unit 41, an operating number storage unit 42, and a cooling water refrigerator inlet temperature detection unit 43. In addition, the control device 40 includes an operation state map storage unit 44 and an operation number determination unit 45.

  The production heat quantity calculation unit 41 detects the temperature of the chilled water measured by the chilled water thermometer 16 and the temperature of the chilled water measured by the chilled water return thermometer 26, and calculates the temperature difference between the chilled water. Further, the manufacturing calorific value calculation unit 41 acquires the chilled water flow rate passing through the chilled water return header 33 measured by the chilled water return header flow meter 33A or the chilled water flow rate passing through the chilled water return header 34 measured by the chilled water return header flow meter 34A. To do.

  Further, the production heat quantity calculation unit 41 reads the current number of operating refrigerators stored in the operating number storage unit 42. The manufacturing heat quantity calculation unit 41 is based on the calculated temperature difference of the chilled water and the flow rate of the chilled water passing through the chilled water return header 33 or the chilled water return header 34 according to the read number of operating chillers. Is calculated, and a load factor with respect to the capacity of one refrigerator (hereinafter referred to as “capacity load factor of one refrigerator”) is calculated. The production heat quantity calculation unit 41 outputs the calculated capacity load factor of one refrigerator to the operating number determination unit 45.

  The operating number storage unit 42 temporarily stores the current number of operating refrigerators determined by the operating number determination unit 45. When the number of operating units is switched, the number of operating units after switching is overwritten and stored. The number-of-operations storage unit 42 outputs the stored number of operating refrigerators to the production heat quantity calculation unit 41 in response to the reading of the production heat quantity calculation unit 41.

  The cooling water refrigerator inlet temperature detection unit 43 includes the cooling water refrigerator inlet temperature of the first refrigerator 10 measured by the first cooling water thermometer 14 and the second refrigerator 10 measured by the second cooling water thermometer 24. Detect the cooling water refrigerator inlet temperature. The cooling water refrigerator inlet temperature detection unit 43 outputs the detected cooling water refrigerator inlet temperature to the operating number determination unit 45.

  The driving state map storage unit 44 stores the driving state map shown in FIG. As shown in FIG. 3, the operation state map includes an optimum number determination line JL that determines the number of the two refrigerators 10 and 20 to be operated. The optimum number determination line JL is a criterion for determining the number of refrigerators whose operation results are relatively large. The operation state map storage unit 44 outputs the stored operation state map to the operation number determination unit 45 in response to the reading of the operation number determination unit 45. Moreover, in the control apparatus 40, the operating number of the refrigerators 10 and 20 is determined using this optimal number determination line JL. The operation state map shown in FIG. 3 corresponds to the optimum vehicle state determination operation state map of the present invention.

  The operating heat capacity calculation unit 41 outputs the capacity load factor of one refrigerator, and the cooling water refrigerator inlet temperature detection unit 43 outputs the cooling water refrigerator inlet temperature to the operating unit determination unit 45. In addition, the operating number determination unit 45 reads the number of operating refrigerators from the operating number storage unit 42 and reads the operating state map from the operation state map storage unit 44.

  The operating unit determination unit 45 refers to the operating state map corresponding to the operating number of the refrigerators with reference to the operating load map corresponding to the operating number of the refrigerators with reference to the capacity load factor of the single refrigerator and the cooling water inlet temperature. The number-of-operations determination unit 45 operates the refrigerators 10 and 20 according to the determined number of refrigerators to be operated. Further, the determined number of operating refrigerators is stored in the operating number storage unit 42.

  Next, a procedure for generating the optimum number judgment line JL will be described. Here, the example using the synthetic | combination COP of a refrigerator and a cooling water pump as an operation result is shown. The optimum number determination line JL is generated by obtaining the power consumption of the refrigerator and the cooling water pump for each of the case where one refrigerator is operated and the case where two refrigerators are operated. FIG. 4 is a flowchart showing a procedure for generating the optimum number judgment line JL. One unit when operating one refrigerator corresponds to the first number of the present invention, and two units when operating two refrigerators correspond to the second number of the present invention.

  As shown in FIG. 4, when generating the optimum number judgment line JL, first, the power consumption of the refrigerator is calculated (S1). Here, assuming the respective numerical values for the capacity load factor of one refrigerator and the cooling water inlet temperature, the refrigerator power consumption is calculated based on these two variables. The refrigerator power consumption can be calculated based on the refrigerator characteristics of the refrigerators 10 and 20.

  As the capacity load factor of one refrigerator, 10 variables in 10% increments between 10% and 100% are assumed. Further, as the cooling water refrigerator inlet temperature, 21 variables in increments of 1 ° C. between 12 ° C. and 32 ° C. are assumed. For this reason, refrigerator power consumption is calculated about 210 cases. The power consumption of these refrigerators is calculated for each of the case where one of the refrigerators 10 and 20 is operated and the case where two are operated.

When the refrigerator power consumption is calculated, the following steps S2 to S5 are performed for each of 210 cases, and the cooling water pump power consumption is calculated. In calculating the cooling water pump power consumption, first, the heat dissipation amount E (E ₁ , E ₂ ) of the cooling water is calculated (S2). At this time, the heat radiation amount E ₁ of the cooling water when one of the refrigerators 10 and 20 is operated is calculated by the following equation (1). Also, the heat radiation amount E ₂ of the cooling water in the case of operating two of the refrigerating machines 10 and 20 is calculated by the following equation (2).
Heat dissipation E ₁ = (Production heat of one refrigerator) · (1 + COP ₁ ) / COP ₁ ·· (1)
Heat release E ₂ = {(Production heat of 2 refrigerators / 2) · (1 + COP ₂ ) / COP ₂ } · 2 (2)
However, COP ₁ : COP of the refrigerator when operating one refrigerator
COP ₂ : COP of the refrigerator when operating two refrigerators (operating at half the output of one)

When the heat dissipation amount of the cooling water is thus obtained, the cooling water amount Q (Q ₁ , Q ₂ ), which is the cooling water amount, is calculated (S3). The cooling water amount Q is calculated using the heat dissipation amount of the cooling water obtained in step S2. At this time, for the cooling water to Q ₁ when operating the one of the refrigerating machines 10 and 20, calculated by the following equation (3). Also, the cooling water amount _{Q 2} in the case of operating two of the refrigerating machines 10 and 20 is calculated by the following equation (4). Δt in the following formulas (3) and (4) is a numerical value determined for preventing COP reduction, and can be an arbitrary numerical value of 5 ° C. or less. Further, when the cooling water amounts Q ₁ and Q ₂ are obtained, the rated cooling water amount Q _r of the refrigerators 10 and 20 is used.

Q ₁ = MAX (E ₁ / Δt, Q _r / 2) (3)
Q ₂ = {MAX (E ₂ / 2Δt, Q _r / 2)} · 2 (4)

Subsequently, a cooling water pump head H (H ₁ , H ₂ ) is calculated (S4). At this time, the cooling water pump head H ₁ in the case of driving the one of the refrigerating machines 10 and 20 is calculated by the following equation (5). Further, the cooling water pump head H ₂ when operating two of the refrigerators 10 and 20 is calculated by the following equation (6). Here, when the cooling water pump heads H ₁ and H ₂ are obtained, the rated pump head H _r in the cooling water pumps 15 and 25 is used.

H ₁ = H _r (Q ₁ / Q _r ) ² (5)
_{H 2 = H r {(Q} 2/2) / Q r} 2 ·· (6)

When the coolant pump head is thus obtained, the coolant pump power consumption is calculated (S5). In order to calculate the cooling water pump power consumption, the cooling water pump power P (P ₁ , P ₂ ) is calculated. At this time, the cooling water pump power P ₁ when operating the one of the refrigerating machines 10 and 20 is calculated by the following equation (7). Also, the cooling water pump power P ₂ in the case of operating two of the refrigerating machines 10 and 20 is calculated by the following equation (8). Here, the pump efficiency η is used.

_{P 1 = Q 1 · H 1} /6120 · η ·· (7)
_{P 2 = {(Q 2 ·} H 2/2) / 6120 · η} · 2 ·· (8)

Using the cooling water pump powers P ₁ and P ₂ , the cooling water pump power consumption when operating one of the refrigerators 10 and 20 and the cooling water pump power consumption when operating two are determined.

When the power consumption of the cooling water pump is obtained, the refrigerators are respectively used in 210 ways when one of the refrigerators 10 and 20 is operated and 210 ways when two of the refrigerators 10 and 20 are operated. The power consumption and the cooling water pump power consumption are added (S6). Subsequently, a combined value of COPs of the refrigerator and the cooling water pump (hereinafter referred to as “synthetic COP”) is calculated for each of the case where one refrigerator is operated and the case where two refrigerators are operated (S7). The synthetic COP can be calculated by the following equation (9). In addition, the combined COP can be calculated for both the case of operating one refrigerator and the case of operating two refrigerators by the following equation (9).
Synthetic COP = Production heat / (Refrigerator power consumption + Cooling water pump power consumption) (9)

  Thus, when the combined COP is obtained for each of the case where one refrigerator is operated and the case where two refrigerators are operated, when one of the refrigerators 10 and 20 is operated and two of the refrigerators 10 and 20 are operated. For each of the operation, the calculated composite COP is graphed (S8) to generate a COP curve.

  An example of the COP curve generated here is shown in FIG. In the graph shown here, the horizontal axis is the capacity load factor of one refrigerator, and the vertical axis is the synthetic COP. FIG. 5A shows a COP curve when one refrigerator is operated (hereinafter referred to as “first COP curve”), and FIG. 5B shows a COP curve when two refrigerators are operated. (Hereinafter referred to as “second COP curve”).

  Moreover, in Fig.5 (a), the thing for every cooling water refrigerator inlet temperature is shown about the 1st COP curve CL1. Here, the first COP curve CL1 located on the uppermost side is the case where the cooling water refrigerator inlet temperature is 12 ° C., and hereinafter, the cooling water refrigerator inlet temperature increases by 1 degree as the temperature decreases downward. And the 1st COP curve CL1 located in the lowest side is a case where the cooling water refrigerator inlet temperature is 32 degreeC.

  Similarly, in FIG. 5B, the second COP curve CL2 is shown for each cooling water refrigerator inlet temperature. Here, the second COP curve CL2 located on the uppermost side is the case where the cooling water refrigerator inlet temperature is 12 ° C., and hereinafter, the cooling water refrigerator inlet temperature rises by 1 degree as it falls downward. And the 2nd COP curve CL2 located in the lowest side is a case where the cooling water refrigerator inlet temperature is 32 degreeC.

  Then, the graph shown in FIG. 5A and the graph shown in FIG. 5B are overlapped to generate a graph in the generation operation state map shown in FIG. The graph in FIG. 5C represents the relationship between the first COP curve CL1 and the second COP curve CL2. Further, the generation operation state map shown in FIG. 5C is the operation state map for generating the optimum number determination line according to the present invention.

  Then, the intersection of 1st COP curve CL1 and 2nd COP curve CL2 in case cooling-water refrigerator inlet temperature is the same temperature is calculated | required. In the generation operation state map shown in FIG. 5C, 21 intersections between the first COP curve CL1 and the second COP curve CL2 are obtained, which is the same as the number of temperatures set as the cooling water refrigerator inlet temperature. Then, 21 intersections are connected (S9). A line connecting the 21 intersections becomes a preliminary optimum number judgment line PJL generated preliminary when the optimum number judgment line JL shown in FIG. 3 is generated.

  In the generation operation state map in which the preliminary optimum number determination line PJL is generated, the vertical axis is the composite COP, and the horizontal axis is the capacity load factor of one refrigerator. This preliminary optimum number judgment line PJL is converted into an operating state map in which the vertical axis is the cooling water refrigerator inlet temperature and the horizontal axis is the capacity load factor of one refrigerator (S10). Thus, by converting the preliminary optimum number judgment line PJL onto the operation state map, the optimum number judgment line JL shown in FIG. 3 can be obtained. These 21 points on the optimum number determination line JL are points corresponding to the cooling water temperature of the present invention.

  The control device 40 uses the optimum number determination line JL thus obtained, the capacity load factor of one refrigerator and the cooling water refrigerator inlet temperature measured by the cooling water thermometers 14 and 24, and Find the number of units in operation. Hereinafter, the procedure for determining the number of operating refrigerators will be described with reference to FIG. FIG. 6 is a flowchart showing a procedure for determining the number of operating refrigerators.

  As shown in FIG. 6, when determining the number of operating refrigerators, first, the capacity load factor of one refrigerator is calculated (S11). The capacity load factor of one refrigerator is the temperature difference between the chilled water measured by the chilled water forward thermometer 16 and the chilled water return thermometer 26 and the chilled water flow rate passing through the chilled water forward header 33 measured by the chilled water forward header flow meter 33A or The product of the cold water flow rate passing through the cold water return header 34 measured by the cold water return header flowmeter 34A is divided by the capacity of one refrigerator.

  Subsequently, the cooling water refrigerator inlet temperature is detected (S12). As the cooling water refrigerator inlet temperature, when one refrigerator is operated, the temperatures of the cooling water thermometers 14 and 24 provided in the pipes connected to the operated refrigerator are used. When two refrigerators are operated, the average of the temperature of the first cooling water thermometer 14 and the temperature of the second cooling water thermometer 24 can be used. Then, the cooling water refrigerator inlet temperature and the capacity load factor of one refrigerator are referred to the operation state map shown in FIG. 3, and a judgment point as an operation state is set (S13). This judgment point can be easily plotted and set by the coordinates of the capacity load factor of one refrigerator calculated in step S11 and the coordinates of the cooling water refrigerator inlet temperature detected in step S12.

  Then, the positional relationship between the set determination point and the optimum number determination line JL is determined (S14). Thereafter, it is determined whether the number of operating refrigerators is one or two (S15), and the number of operating refrigerators is determined according to the determination result. Here, when the number of operating refrigerators is 1, it is determined whether or not the determination point is on the left side of the optimal number determination line JL (S16).

  As a result, when the determination point is on the left side of the optimal number determination line JL, the determination point does not exceed the optimal number determination line JL. In this case, it is possible to obtain a COP that is higher when operated with one operating refrigerator than when operated with two refrigerators. Therefore, the number of operating refrigerators is determined as one without switching the number of operating units (S17).

  When the determination point is on the right side of the optimum number determination line JL, the optimum number determination line JL is exceeded. In this case, the operation with two refrigerators can obtain a higher COP than the operation with one refrigerator. Therefore, the number of operating refrigerators is switched from 1 to 2, and the number of operating refrigerators is determined to be 2 (S18).

  If it is determined in step S15 that the number of operating refrigerators is two, it is determined whether or not the determination point is on the right side of the optimal number determination line JL (S19). As a result, when the determination point is on the right side of the optimum number determination line JL, the optimum number determination line JL is not exceeded. In this case, it is possible to obtain a COP that is higher when operated with two operating refrigerators than when operated with one refrigerator. Therefore, the number of operating refrigerators is determined as two without switching the number of operating units (S18).

  On the other hand, when the determination point is on the left side of the optimum number determination line JL, the optimum number determination line JL is exceeded. In this case, it is possible to obtain a higher COP in the operation with one refrigerator than in the operation with two refrigerators. Therefore, the number of operating refrigerators is switched from 2 to 1, and the operating number of refrigerators is determined to be 1 (S17).

  Thus, in the refrigerator system according to the present embodiment, the number of refrigerators to be operated is determined using the optimum number determination line JL. For this reason, the number of operating refrigerators can be determined without performing complicated calculations. Therefore, it is possible to determine the number of operating refrigerators while reducing the burden when controlling the refrigerator in the refrigerator system.

  Further, in the refrigerator system according to the present embodiment, a preliminary optimum number is generated using a generation operation state map in which the vertical axis shown in FIG. 5C is a composite COP and the horizontal axis is a capacity load factor of one refrigerator. A decision line PJL is generated, and the preliminary optimum number determination line PJL is converted into an optimum number determination line JL in the operation state map shown in FIG. 3, thereby generating the optimum number determination line JL. For this reason, since the optimal number determination line JL can be generated using the synthetic COP, the optimal number determination line JL can be easily generated.

  Further, when the refrigerator is operated, the refrigerator manufacturing heat quantity that can be used for calculation of the cooling water temperature and the capacity load factor of one refrigerator is usually measured. In addition, the determination point at an arbitrary time point is determined by two variables such as the cooling water temperature and the capacity load factor of one refrigerator. Therefore, the control is performed by determining the optimum number using the optimum number judgment line JL in the operation state map in which the vertical axis is the cooling water refrigerator inlet temperature and the horizontal axis is the capacity load factor of one refrigerator. The optimum number can be determined while reducing the calculation load on the device 40. Furthermore, since the optimum number judgment line JL is formed by connecting the optimum number of branch points when there are 21 cooling water temperatures, it is easy even when the cooling water temperature is a temperature other than the 21 cooling water temperatures. Judgment points can be plotted on the driving state map to determine the optimum number.

  In this embodiment, in determining the number of operating refrigerators, the auxiliary machine of the refrigerator system is considered, more specifically, the variable flow rate control of the cooling water pump is considered, and the refrigerator and the cooling water pump are The combined COP is improved. Thus, the reason for determining the number of operating refrigerators while improving the COP in consideration of the auxiliary equipment of the refrigerator system is that the amount of cooling water and the pump power consumption by the variable flow rate control of the cooling water pump that is generally performed are This is because the amount of heat release varies depending on the number of operating refrigerators and the COP of the refrigerator. In this way, by determining the optimum number of refrigerators to improve the COP of the refrigerator and the cooling water pump, it is possible to realize a highly efficient operation as a refrigerator system.

  Next, a second embodiment of the present invention will be described. The present embodiment mainly differs from the first embodiment in the aspect of the optimum number determination line. For this reason, the apparatus configuration is the same as that of the first embodiment shown in FIG. In the following, the procedure for generating the optimum number determination line, which is a difference, will be mainly described.

  In the present embodiment, an optimum number determination line is set, and a switching delay that is a range for delaying the switching of the number of operating units after the operating state of the refrigerator exceeds the optimum number determination line with respect to the set optimum number determination line. As the range, a non-switching range is set on the optimum number judgment line. FIG. 7 is a diagram illustrating an operation state map including an optimum number determination line in the second embodiment. As shown in FIG. 7, the optimum number determination line in the operation state map according to the present embodiment has a deviation from the optimum number determination line JL generated in the same manner as in the first embodiment, and sets a predetermined non-switching range. Then, the corrected optimum number judgment lines JL1, JL2 are set. The non-switching range is a range sandwiched between the optimum number determination line JL and the corrected optimum number determination line JL1, JL2. Therefore, setting the non-switching range is synonymous with converting the optimum number determination line JL to the corrected optimum number determination line JL1, JL2.

  Here, the first corrected optimum number determination line JL1 and the second corrected optimum number determination line JL2 are set. The first modified optimum number judgment line JL1 is set by shifting the optimum number judgment line JL to the side where the capacity load factor of one refrigerator becomes smaller, and from the state where two refrigerators are operated. It is used as a reference when changing to a state in which one refrigerator is operating.

  On the other hand, the second modified optimum number judgment line JL2 is set by shifting the optimum number judgment line JL to the side where the capacity load factor of one refrigerator becomes larger, and is operating one refrigerator. It is used as a reference when changing from a state to a state where two refrigerators are operating. In this way, by setting the first corrected optimum number determination line JL1 and the second corrected optimum number determination line JL2 and setting a predetermined non-switching range in the optimum number determination line, the number of switching of the number of operating units of the refrigerator can be reduced. It can prevent becoming excessive.

  If the non-switching range is set in the optimum number judgment line JL, the energy saving performance is reduced accordingly. For this reason, the non-switching range set to the optimal number determination line JL can be determined in consideration of the energy saving reduction. At this time, the non-switching range is set in the optimum number judgment line JL based on an allowable numerical value, which is 5% in this embodiment, as the energy saving performance reduction.

  Here, generation of the corrected optimum number judgment lines JL1 and JL2 will be described. FIG. 8 is a flowchart showing a procedure for generating a corrected optimum number judgment line. When generating the corrected optimum number judgment lines JL1, JL2, as in the case of generating the optimum number judgment line JL, the preliminary corrected optimum number judgment lines PJL1, PJL2 are generated in the generation operation state map, and the generated spare The optimally corrected optimum number judgment line is converted on the operation state map. As shown in FIG. 8, when generating the preliminary corrected optimal number determination lines PJL1 and PJL2, first, the preliminary optimal number determination line PJL is generated (S21). The procedure for generating the preliminary optimum number determination line PJL is the same as that in the first embodiment.

  When the preliminary optimum number determination line PJL is generated, a reference point is generated (S22). Here, the reference point will be described with reference to FIGS. In the graphs shown in FIGS. 9A and 9B, the vertical axis is the composite COP, and the horizontal axis is on the generation operation map in which the capacity load factor of one refrigerator is shown. Now, for a certain cooling water refrigerator inlet temperature, the vicinity of the intersection of the first COP curve CL1 and the second COP curve CL2 is enlarged and shown in FIGS.

  As shown in FIG. 9 (a), the preliminary optimal number determination is performed for the intersection CA of the first COP curve CL1 and the second COP curve CL2 when the preliminary optimal number determination line PJL (see FIG. 5 (c)) is generated. The point at the time of generating the line PJL is moved to the side where the capacity load factor of one refrigerator becomes smaller on the second COP curve CL2 to be a first reference point CB.

  Here, a point on the first COP curve CL1 that has the same capacity load factor of one refrigerator as the first reference point CB is defined as a first comparison point CBC. Under this condition, it is assumed that the point used when generating the preliminary optimum number determination line PJL is moved from the intersection CA to the first reference point CB. In this case, in the case where the preliminary optimal number determination line PJL is generated using the intersection CA and the case where the preliminary optimal number determination line PJL is generated using the first reference point CB, the COP at the reference point CB, The energy saving performance is reduced by the difference from the COP at the comparison point CBC. By generating the energy saving property that decreases here at a predetermined value, 5% in the present embodiment, it is possible to prevent the number of switching of the number of operating refrigerators from being excessive and to maintain the energy saving property.

  Therefore, as shown in FIG. 9A, the capacity load factor of one refrigerator is the same while moving the point from the intersection CA along the second COP curve CL2 in the direction in which the capacity load factor of the refrigerator becomes smaller. The difference between the points on the first COP curve CL1 is calculated. The point on the second COP curve CL2 at the time when the difference in power consumption between the point on the second COP curve CL2 and the point on the first COP curve CL1 becomes 5% of the power consumption at the intersection CA is the first reference point. CB. Specifically, a point satisfying the following expression (10) is defined as a first reference point CB.

(Load factor _CA / COP _CA ) · 5% = Load factor _CB / COP _CB −Load factor _CBC / COP _CBC ·· (10)
Here, load factor _CA : capacity load factor of one refrigerator at intersection CA
COP _CA : Synthetic COP at the intersection CA
Load factor _CBC : Capacity load factor of one refrigerator at the first comparison point CBC
COP _CBC : Synthetic COP at the first comparison point CBC
Load factor _CB : One refrigerator capacity load factor at the first reference point CB
COP _CB : synthetic COP at the first reference point CB

  In the COP curves CL1 and CL2, the COP is calculated in increments of 10% on the horizontal axis. For this reason, the COP value at the capacity load factor of any one refrigerator is calculated using the slope of a straight line connecting two points in increments of 10%.

  Further, as shown in FIG. 9 (b), the capacity load factor of one refrigerator is the same while moving the point from the intersection CA along the first COP curve CL1 in the direction in which the capacity load factor of the refrigerator becomes larger. The difference between the points on the second COP curve CL2 is calculated. The point on the first COP curve CL1 at the time when the difference in power consumption between the point on the first COP curve CL1 and the point on the second COP curve CL2 becomes 5% of the power consumption at the intersection CA is the second reference point. CC. Here, a point on the second COP curve CL2 having the same capacity load factor of one refrigerator as the second reference point CC is defined as a second comparison point CCC, and a point satisfying the following expression (11) is defined as a second reference point CC. .

(Load factor _CA / COP _CA ) · 5% = Load factor _CC / COP _CC −Load factor _CCC / COP _CCC ·· (11)
Here, load factor _CCC : one refrigerator capacity load factor at the second comparison point CCC
COP _CCC : Synthetic COP at the second comparison point CCC
Load factor _CC : Capacity load factor of one refrigerator at the second reference point CC
COP _CC : Composite COP at the second reference point CC

  When the first reference point CB and the second reference point CC are generated in this way, the first reference point CB and the second reference point CC are generated for 21 different temperatures in increments of 1 ° C. of the cooling water refrigerator inlet temperature. Thereafter, 21 first reference points CB are respectively connected and 21 second reference points CC are respectively connected (S23). A line connecting the first reference points CB becomes a first preliminary correction optimum number determination line PJL1. Further, the line connecting the second reference points CC becomes the second preliminary correction optimum number determination line PJL2.

  The preliminary corrected optimal number determination lines PJL1 and PJL2 generated in this way are not curves obtained by simply shifting the optimal number determination line PJL. Can be. When the preliminary correction optimum number judgment line is generated in this way, the preliminary correction optimum number judgment line PJL1 and PJL2 are converted from the generation operation state map to the operation state map shown in FIG. JL1 and JL2 are generated. In this way, the generation of the corrected optimum number judgment line is finished.

  When the corrected optimal number determination line is generated, the control device 40 stores the corrected optimal number determination lines JL1 and JL2. Then, a determination point is obtained in the same manner as in the first embodiment. Then, the number of operating refrigerators is determined based on whether or not the corrected optimum number judgment line is exceeded. When the corrected optimum number judgment line is exceeded, the operating number is changed to determine the number of operating refrigerators. If the corrected optimum number judgment line is not exceeded, a determination is made that maintains the number of operating refrigerators without changing the number of operating units.

  As described above, in the refrigerator system according to the present embodiment, the number of refrigerators to be operated is determined using the corrected optimum number determination line as in the first embodiment. For this reason, the number of operating refrigerators can be determined without performing complicated calculations. Therefore, it is possible to determine the number of operating refrigerators while reducing the burden when controlling the refrigerator in the refrigerator system.

  Moreover, in the refrigerator system which concerns on this embodiment, the correction optimal number determination line which set the non-switching range to the optimal number determination line is used. For this reason, even if the optimum number judgment line is slightly exceeded, the number of operating refrigerators is not switched. Therefore, it is possible to prevent the number of switching of the number of operating refrigerators from being excessive.

  Furthermore, when generating the corrected optimum number judgment line, energy saving is taken into consideration, and when the energy saving is reduced by 5% from the optimum number judging line, the number of operating refrigerators is changed. For this reason, it is possible to switch the number of operating refrigerators in consideration of the excessive switching of the number of operating refrigerators and the balance of energy saving. Therefore, it is possible to more suitably prevent the number of operating units from being switched excessively, and not to impair energy saving.

  Subsequently, a third embodiment of the present invention will be described. In the present embodiment, similarly to the first embodiment, it is possible to determine the number of operating refrigerators using the optimum number determination line. Furthermore, the present embodiment is mainly different from the first embodiment in that the optimum number determination line can be corrected while the refrigerator system is operating. For this reason, the refrigerator system is the same as that of the first embodiment except for the configuration of the control device.

  Hereinafter, the correction procedure of the control device and the optimum number determination line JL according to the present embodiment will be mainly described with reference to FIGS. 10 and 11. FIG. 10 is a block configuration diagram of the control device according to the present embodiment. As shown in FIG. 10, the control device 50 according to the present embodiment is similar to the first embodiment in that the production heat quantity calculation unit 41, the operating unit storage unit 42, the cooling water refrigerator inlet temperature detection unit 43, the operation A state map storage unit 44 and an operation number determination unit 45 are provided. Further, the control device 50 includes an operation state storage unit 51 and an optimum number determination line correction unit 52 in addition to the above configuration.

  Among these, the production heat quantity calculation unit 41, the number-of-operations storage unit 42, and the operation state map storage unit 44 function in the same manner as in the first embodiment. Here, the cooling water refrigerator inlet temperature detection unit 43 outputs the detected cooling water refrigerator inlet temperature to the operating state storage unit 51 in addition to the operating number determination unit 45.

  Similarly to the first embodiment, the operating number determination unit 45 operates the refrigerators 10 and 20 according to the determined operating number of the refrigerators, and determines the determined operating number of the refrigerators as the operating number. The data is stored in the storage unit 42. Further, the operating number determination unit 45 outputs the combined COP calculated when determining the number of operating refrigerators to the operating state storage unit 51. In addition, when the number of operating units is switched, the operating unit switching information is output to the optimum number determining line correcting unit 52. Here, the COP curve and the optimum number judgment line used when determining the number of operating units are given to the operating unit switching information.

  The operation state storage unit 51 stores the cooling water refrigerator inlet temperature output from the cooling water refrigerator inlet temperature detection unit 43 and the synthetic COP output from the operating number determination unit 45. The operation state storage unit 51 stores the cooling water refrigerator inlet temperature and the synthesized COP at 1 minute intervals. The operation state storage unit 51 outputs the stored cooling water refrigerator inlet temperature and the synthesized COP to the optimal number determination line correction unit 52 in response to the reading of the optimal number determination line correction unit 52. In addition, the cooling water refrigerator inlet temperature and synthetic | combination COP memorize | stored in the driving | running state memory | storage part 51 can be suitably variably set according to operation, such as a 30-second space | interval and a 5-minute space | interval instead of a 1-minute space | interval.

  The optimal number determination line correction unit 52 corrects the optimal number determination line JL when the operating number switching information is output from the operating number determination unit 45. When the optimum number determination line JL is corrected, the cooling water refrigerator inlet temperature and the combined COP before and after the output of the operation number switching information stored in the operation state storage unit 51 are read. The optimal number determination line correction unit 52 corrects the optimal number determination line JL given to the operating number switching information based on the cooling water refrigerator inlet temperature and the synthesized COP read from the operation state storage unit 51. When the number of operating units of the refrigerators 10 and 20 is switched, the optimum number judgment line JL is corrected when the combined COP of the refrigerators 10 and 20 becomes relatively smaller after switching the operating units than before switching. This is done by moving the optimum number judgment line JL in the direction in which the number of operating units is switched. Here, the direction in which the number of operating units is switched when moving the optimum number determining line JL specifically refers to the direction in which the number of operating units changes across the optimal number determining line JL. The optimal number determination line correction unit 52 corrects the optimal number determination line JL stored in the operation state map storage unit 44 in accordance with the correction result of the optimal number determination line JL. Further, the optimum number judgment line JL is corrected by moving the optimum number judgment line JL along the horizontal axis direction of the operation state map.

  Next, the procedure for correcting the optimum number judgment line JL will be described with reference to FIG. FIG. 11 is a flowchart showing a processing procedure for correcting the optimum number judgment line JL. The flowchart shown in FIG. 11 is executed at 1-minute intervals. For this reason, the update etc. of the various data which are output and memorize | stored in the driving | running state memory | storage part 51 are performed at intervals of 1 minute.

  As shown in FIG. 11, when the optimal number determination line JL is corrected, first, the operating number determination unit 45 calculates a combined COP when determining the number of operating numbers (S31). Next, the combined COP calculated by the operating number determination unit 45 is stored in the operating state storage unit 51 (S32). At this time, the cooling water refrigerator inlet temperature detection unit 43 outputs the cooling water refrigerator inlet temperature, and the operating state storage unit 51 also stores the cooling water refrigerator inlet temperature at the same time (S32).

  Subsequently, it is determined whether or not the number of operating units has been switched (S33). Whether or not the number of operating units has been switched is determined depending on whether or not the operating unit number switching information has been output to the optimum number determining line correction unit 52. As a result, when the number of operating units is not switched, the oldest information is deleted from the synthesized COP stored in the operating state storage unit 51 (S34). At this time, the oldest information about the cooling water refrigerator inlet temperature is also deleted.

  On the other hand, when it is determined that the number of operating units has been switched, the optimum number determining line correction unit 52 determines the cooling water refrigerator inlet temperature and the combined COP before the output of the operating unit switching information stored in the operating state storage unit 51. Is read. The optimum number judgment line correction unit 52 calculates a value obtained by rounding the read cooling water refrigerator inlet temperature to an integer (hereinafter referred to as “cooling water refrigerator inlet temperature before switching”). Further, the composite COP before the output of the read operation number switching information is set as the pre-switching COP (S35).

  Then, the optimum number determination line correction unit 52 reads the post-switching cooling water refrigerator inlet temperature and the synthesized COP after the output of the operating number switching information stored in the operating state storage unit 51. The optimum number determination line correction unit 52 calculates a value obtained by rounding the read cooling water refrigerator inlet temperature to an integer (hereinafter referred to as “cooling water refrigerator inlet temperature after switching”). The combined COP after the output of the read operation number switching information is set as the post-switching COP (S35).

  Subsequently, the COP after switching and the COP before switching are compared, and it is determined whether or not the COP after switching is larger than the COP before switching (S36). As a result, when the post-switching COP is larger, the optimum number determination line JL is correct. In this case, the optimum number judgment line JL is maintained as it is without being modified (S41), and the optimum number judgment line JL modification process is terminated.

  On the other hand, if it is determined that the post-switching COP is equal to or lower than the pre-switching COP, then a ΔCOP ratio, which is the rate of change between the pre-switching COP and the post-switching COP, is calculated (S37). The ΔCOP ratio is calculated by the following equation (12).

  ΔCOP ratio = {(COP before switching−COP after switching) / COP before switching} × 100 (12)

  Then, it is determined whether or not the ΔCOP ratio calculated in step S27 exceeds 5% (S38). Here, when it is determined that the ΔCOP ratio does not exceed 5% (below 5%), it is considered to be within the range of measurement error, so that the optimum number determination line JL is not corrected and is left as it is. Maintaining (S31), the process of correcting the optimum number judgment line JL ends. Note that the numerical value of 5% set here can be variably set according to the operation.

  If it is determined that the ΔCOP ratio exceeds 5% and the cooling water refrigerator inlet temperature is the same before and after switching the number of operating refrigerators, the optimum number determination line JL needs to be corrected. It is thought that. Therefore, it is determined whether or not the pre-switching cooling water refrigerator inlet temperature and the post-switching cooling water refrigerator inlet temperature are the same (S39).

  As a result, when it is determined that the pre-switching cooling water refrigerator inlet temperature and the post-switching cooling water refrigerator inlet temperature are not the same, the pre-switching COP and the post-switching COP may change greatly, so the optimum number determination line JL May be correct. Therefore, in this case, the optimum number determination line JL is maintained without being corrected (S41), and the optimum number determination line JL correction process is terminated.

  On the other hand, when it is determined that the pre-switching cooling water refrigerator inlet temperature is the same as the post-switching cooling water refrigerator inlet temperature, the optimum number determination line JL is corrected (S40). The optimum number judgment line JL is corrected by moving the optimum number judgment line JL in the direction in which the number of operating units is switched. This correction is made 3 minutes after it is determined that the number of operating refrigerators has been switched. Thereafter, the process for correcting the optimum number judgment line JL is terminated. Here, the time of 3 minutes can also be set variably according to the operation.

  In addition, for the pre-switching COP, instead of using the combined COP read before the operation number switching information is output, the average value of the combined COPs for several times before the output of the operating unit switching information can be used. Similarly, for the post-switching COP, instead of using the combined COP read after the output of the operating unit switching information, an average value of the combined COPs for several times after the output of the operating unit switching information can be used. Similarly, for the cooling water refrigerator inlet temperature before switching, instead of using the temperature read before the output of the operating unit switching information, the average value of the temperature for several times before the output of the operating unit switching information can also be used. . Similarly, as the cooling water refrigerator inlet temperature after switching, instead of using the temperature read after the output of the operating unit switching information, the average value of the temperature for several times after the output of the operating unit switching information can be used. As described above, the pre-switching COP and the post-switching COP that are the average values of the combined COP for a plurality of times and the pre-switching cooling water refrigerator inlet temperature and the post-switching cooling water refrigerator inlet temperature that are the average values of the cooling water temperatures for a plurality of times. By using this, it is possible to stabilize the correction operation when correcting the optimum number judgment line JL.

  Thus, by correcting the optimum number judgment line JL when the COP after switching is smaller than the COP before switching, the deviation between the optimum number judgment line JL obtained in the past and the actual operation characteristics can be reduced. Optimal driving can always be performed. Further, even if the preset optimum number judgment line JL is separated from the actual operation characteristics, the optimum number judgment line JL is gradually corrected to the optimum number judgment line JL that conforms to the actual operation characteristics. For this reason, the optimal number determination line JL set in advance can be easily obtained. Further, even when the actual operation characteristics change due to the aging of the refrigerator system 1, the optimum number judgment line JL corresponding to the change in the actual operation characteristics is corrected. For this reason, a large-scale readjustment etc. can be made unnecessary.

  Hereinafter, the principle of correcting the optimum number determination line JL correctly by correcting the optimum number determination line JL when the COP after switching is smaller than the COP before switching will be described. Regarding the principle that the optimum number judgment line JL described here is corrected correctly, the preliminary optimum number judgment line PJL in the generation operation state map in which the vertical axis is the composite COP and the horizontal axis is the capacity load factor of one refrigerator. This will be described using the principle of correcting the above. However, in the operation state map for generation whose vertical axis is the synthetic COP and the operation state map whose vertical axis is the cooling water refrigerator inlet temperature, the horizontal axis is the capacity load factor of one refrigerator. Further, when the optimum number judgment line JL is corrected, the optimum number judgment line JL is moved in the horizontal axis direction of the operation state map, so that the movement amount of the preliminary optimum number judgment line PJL in the generation operation state map is This is the same as the movement amount of the optimum number judgment line JL in the operation state map.

  Now, as shown in FIG. 12, the preliminary optimum number judgment line PJL for generating the optimum number judgment line JL is the first COP curve CL1 when one refrigerator is operated and two refrigerators are operated. The intersection point with the second COP curve CL2 when it is running is generated for each cooling water refrigerator inlet temperature, and is formed by a line connecting the intersection points.

  Here, if the initially set preliminary optimum number judgment line PJL matches the actual operation characteristics, the value of the combined COP is obtained when the operation of one refrigerator is switched to the operation of two. Rises at the capacity load factor of one refrigerator on the preliminary optimum number judgment line PJL. The characteristic that the value of the combined COP increases with the capacity load factor of one refrigerator on the preliminary optimum number judgment line PJL as a boundary can be seen although the rate of change is different at any temperature. Therefore, when the preliminary optimum number determination line PJL matches the actual operation characteristics, the value of the composite COP always increases when the number of operating units is switched.

  Now, consider the case where the preliminary optimum number judgment line PJL is different from the actual operation characteristics. FIG. 12 shows the first COP curve CL1, the second COP curve CL2, and the preliminary optimum number determination line PJL obtained by calculation. In addition, an assumed first COP curve ImaCL1 that is considered to have actual driving characteristics is indicated by a broken line. Here, the combined COP of each point in the assumed first COP curve ImaCL1 is a numerical value lower than the combined COP of each point in the first COP curve CL1 at the same refrigerator capacity load factor. In this case, the difference in the actual operation characteristics in the second COP curve CL2 can be ignored.

  In this case, when the load on the refrigerator system 1 increases during operation of one unit and the judgment point exceeds the preliminary optimum number judgment line PJL (exceeds one refrigerator capacity load factor Lt), the freezing is performed. The number of operating machines can be switched from one to two. Further, when the number of operating refrigerators is switched from one to two, COP increases by ΔCOP. Further, when the load applied to the refrigerator system 1 is reduced and the number of operating refrigerators is switched from two to one, the COP decreases by ΔCOP.

  The reason why the COP decreases when the number of operating refrigerators is switched from two to one is that the combined COP at each point in the assumed first COP curve ImaCL1 is the same capacity load of one refrigerator in the first COP curve CL1 It is a numerical value lower than the combined COP of each point at the rate.

  Although not shown, when the assumed second COP curve based on the actual driving characteristics is a numerical value lower than the second COP curve CL2, the combined COP of each point in the assumed second COP curve ImaCL2 is the same in the second COP curve CL2. It becomes a numerical value lower than the combined COP at each point when the capacity load factor of one refrigerator is. For this reason, even when switching from one to two, the same phenomenon as when switching from two to one in the state of FIG. 12 occurs. Furthermore, when the combined COP of each point in the assumed first COP curve ImaCL1 is a higher numerical value than the combined COP of each point in the first COP curve CL1, The same phenomenon as when switching from two to one in the state of 12 occurs.

  Therefore, when the combined COP is lowered by switching the number of operating units, the optimal number determination line JL generated from the preliminary optimal number determination line PJL and the preliminary optimal number determination line PJL at the cooling water refrigerator inlet temperature at that time is An error is included. In the case shown in FIG. 12, the preliminary optimal number determination line PJL passes on the intersection (a point on the capacity load factor Lta of one refrigerator) of the assumed first COP curve ImaCL1 and the second COP curve CL2. Here, the direction in which the number of operating units changes across the preliminary optimum number determination line PJL is the direction in which the capacity load factor of one refrigerator has decreased.

  Based on this consideration, the preliminary optimum number judgment line PJL is corrected. In principle, when the combined COP decreases after the number of operating units is switched, the preliminary optimal number determination line PJL is corrected. Here, for example, when the combined COP of each point in the assumed first COP curve ImaCL1 is a numerical value lower than the combined COP of each point at the same capacity load factor of one refrigerator in the first COP curve CL1, The preliminary optimum number determination line PJL includes an error. At this time, if the number of operating refrigerators is switched from one to two, the composite COP increases, and the preliminary optimum number determination line PJL cannot be corrected. However, the capacity load factor of one refrigerator usually repeats increasing and decreasing. For this reason, the optimal number determination line JL can be appropriately corrected by correcting the preliminary optimal number determination line PJL only when the combined COP decreases.

  Further, for example, as shown in FIG. 13, when the number of operating units is switched from two to one when moving from the first determination point Pa to the second determination point Pb, in the vicinity of the preliminary optimal number determination line PJL. If the composite COP is lowered, the composite COP is lowered even if the preliminary optimal number determination line PJL and the COP curves CL1 and CL2 are correct, and it is determined that the preliminary optimal number determination line PJL needs to be corrected. May end up.

  Therefore, the cooling water refrigerator inlet temperature and the synthetic COP are calculated every minute, and the post-switching COP and the pre-switching COP obtained based on the calculation results for two minutes are compared. In this way, by minutely sampling, a minute change amount of the synthesized COP can be captured. Therefore, it is possible to prevent erroneous correction of the preliminary optimum number judgment line PJL when the combined COP is lowered in the vicinity of the preliminary optimum number judgment line PJL.

  Further, when the amount of decrease in the combined COP is large, in the present embodiment, the preliminary optimal number determination line PJL is corrected when the ΔCOP ratio exceeds 5%. In the performance data that the present inventors have found, the load change amount of the refrigerator for one minute is generally recorded within 1 GJ / h. Further, it is assumed that the number of operating units is switched when the cooling water refrigerator inlet temperature is 25 ° C to 28 ° C.

  Under such recognition, in the actual refrigerator system that the present inventors know, considering the amount of decrease in the synthetic COP, the first COP curve CL1 and the second COP when the cooling water refrigerator inlet temperature is 25 ° C. to 28 ° C. On the curve CL2, the load change amount 1GJ / h of the refrigerator for 1 minute corresponds to 5% of the ΔCOP ratio. Therefore, since the change amount of the ΔCOP ratio captured by sampling for one minute is considered to be 5% or less, the preliminary optimum number judgment line PJL is corrected when the change amount of the ΔCOP ratio exceeds 5%.

  When the preliminary optimum number judgment line PJL is corrected, among the points plotted when generating the preliminary optimum number judgment line, the cooling water refrigerator inlet when it is judged that the preliminary optimum number judgment line PJL is to be corrected. The point closest to the temperature (hereinafter referred to as “movement target point”) is moved in the direction in which the number of operating refrigerators is switched. When it is determined that the preliminary optimum number determination line PJL is to be corrected, the cooling water refrigerator inlet temperature before and after the switching is the same, so the cooling water refrigerator inlet temperature is used.

  Further, the movement amount ΔJL of the movement target point when moving the point of the preliminary optimum number determination line PJL is obtained as follows. Consider the slopes of the COP curves CL1 and CL2 in the vicinity of the preliminary optimum number judgment line PJL when the cooling water refrigerator inlet temperature, which is considered to cause switching of the number of operating units, is 25 ° C. to 28 ° C.

  Here, the slope of the first COP curve CL1 is, for example, approximately −0.03 when the cooling water refrigerator inlet temperature is 25 ° C. to 28 ° C., for example. At this time, the slope of the second COP curve CL2 is approximately 0.03. For this reason, as shown in FIG. 14, the first COP curve CL1 and the second COP curve CL2 can be expressed approximately symmetrically.

  Here, it is assumed that the actual operation characteristic of the first COP curve CL1 has changed to the assumed first COP curve ImaCL1, and that the pre-switching COP has changed from the starting point Pc on the second COP curve CL2 to the position of the assumed moving point Pd. To do. This assumed movement point Pd is on the current optimum number determination line and becomes a movement target point. In this case, the difference in the combined COP between the starting point Pc and the assumed moving point Pd is about 0.4, and a decrease of about 5% occurs from the pre-switching COP to the post-switching COP. Therefore, it is considered that the movement of the preliminary optimum number judgment line PJL should be performed when the reduction rate of the combined COP exceeds about 5% after switching the number of operating refrigerators.

  For example, when the COP after switching is further decreased by 5% and decreased by 10%, the actual movement point Pe that is the actual movement point is lowered vertically from the assumed movement point Pd, and the actual movement point and the actual movement point Pc. The difference of the synthetic COP from the point Pe is considered to be about 0.8. In this case, the actual first COP curve is considered to be an assumed first COP curve ImaCL1 having a lower synthetic COP than the first COP curve CL1.

  In this case, it can be considered that the actual preliminary optimum number determination line PJL passes through the intersection point Pf between the second COP curve CL2 and the assumed first COP curve ImaCL1. If the movement of a point on the preliminary optimum number judgment line PJL (hereinafter referred to as “PJL point”) is approximated by horizontal movement, the PJL point after movement is the same capacity load factor of one refrigerator as the intersection Pf. And is a point Pg that is the same composite COP as the assumed movement point Pd. Here, the direction in which the number of operating units changes across the preliminary optimum number determination line PJL is the direction in which the Pc starting point moves to the assumed moving point Pd, in other words, the direction in which the capacity load factor of one refrigerator decreases.

  Further, the difference in capacity load factor of one refrigerator between the starting point Pc and the assumed moving point Pd and between the starting point Pc and the actual moving point Pe is about 15%. The difference in the capacity load factor of one refrigerator between the assumed movement point Pd and actual movement point Pe and the intersections Pf and PJL points Pg is about 7.5%. The difference of about 7.5% in the capacity load factor of one refrigerator is a necessary movement amount when moving the movement target point on the preliminary optimum number determination line PJL.

  When the movement amount ΔJL for moving the movement target point is set, the movement amount ΔJL is set to a movement amount smaller than the necessary movement amount of the movement target point shown in FIG. Then, as the operation is continued, the preliminary optimum number determination line PJL gradually moves, and fluctuations such as increase and decrease in the preliminary optimum number determination line PJL can be prevented.

  Therefore, the movement amount ΔJL of the movement target point is set so that the movement amount of the movement target point when the ΔCOP ratio is 10% is equal to or less than 7.5% of the capacity load factor of one refrigerator. In the present embodiment, the movement amount ΔJL is calculated and set by the following equation (13).

  ΔJL = (ΔCOP ratio−5) / 2 (13)

  When the above equation (13) is used, for example, when the cooling water refrigerator inlet temperature is 25 ° C. and the ΔCOP ratio is 10%, the movement amount ΔJL is expressed as {ΔCOP ratio (= 10) −5} / 2 = 2.5, which is smaller than 7.5 / 2 = 3.75, which is half of 7.5 of the required movement amount. Therefore, the movement amount ΔJL is an appropriate movement amount.

  Further, when the cooling water refrigerator inlet temperature is 26 ° C. and the ΔCOP ratio is 8%, the necessary movement amount can be assumed to be 4.5. At this time, the movement amount ΔJL is {ΔCOP ratio (= 8) −5} /2=1.5, which is smaller than 4.5 / 2 = 2.25 which is a half of the necessary movement amount 4.5. Further, the required movement amount when the cooling water refrigerator inlet temperature is 28 ° C. and the ΔCOP ratio is 10% can be assumed to be 8. At this time, the movement amount ΔJL is {ΔCOP ratio (= 10) −5} /2=2.5, which is smaller than 4/2 = 2 which is half of the necessary movement amount 8. For this reason, in any case, the movement amount ΔJL is an appropriate movement amount.

  Therefore, the movement amount ΔJL of the movement target point in the preliminary optimum number determination line PJL can be calculated and set by the above equation (13). By using the equation (13), the movement amount ΔJL of the movement target point increases as the ΔCOP ratio increases. For this reason, it can correct so that it may become close to an actual optimal number judgment line. The numerical values “5” and “2” in the above equation (13) can be appropriately set in consideration of the characteristics of the refrigerator system 1 and the like.

  Further, in correcting the preliminary optimum number judgment line PJL, the movement target point is moved by the movement amount ΔJL calculated based on the above equation (13), and the surrounding area around the movement target point in the preliminary optimum number judgment line PJL is changed. Also move the points. Specifically, as shown in FIG. 15, the amount of movement at a point included in the optimum number determination line JL and at which the cooling water refrigerator inlet temperature is 1 ° C. lower than the movement target point (hereinafter referred to as “first upper target point”). Is ΔJL / 2 which is ½ of the movement amount ΔJL of the movement target point.

  Further, the moving amount at the point where the cooling water refrigerator inlet temperature is 1 ° C. lower than the first upper target point is set to ΔJL / 4, which is ¼ of the moving amount ΔJL of the moving target point. Furthermore, the movement amount at the point where the cooling water refrigerator inlet temperature is 1 ° C. higher than the movement target point (hereinafter referred to as “first lower stage target point”) is ΔJL / 2 which is ½ of the movement amount ΔJL of the movement target point. To do. Then, the movement amount at the point where the cooling water refrigerator inlet temperature is 1 ° C. higher than the first lower stage target point is set to ΔJL / 4 which is ¼ of the movement amount ΔJL of the movement target point.

  As described above, when the preliminary optimum number judgment line PJL is corrected, the points around the movement target point in the preliminary optimum number judgment line PJL are also moved, so that the shape of the preliminary optimum number judgment line after switching is obtained. There is no significant change, and the shape can be made closer to the actual preliminary optimum number judgment line PJL. In addition, when the preliminary optimum number determination line PJL is corrected, the movement amount of the movement target point is maximized, and the movement amounts of the surrounding points are decreased as the distance from the movement target point is increased. For this reason, it is possible to greatly correct the portion of the preliminary optimum number determination line PJL that needs the most correction.

  Further, the corrected optimum number determination lines JL1, JL2 in the second embodiment shown in FIG. 7 are also corrected as in the third embodiment, so that the corrected optimum number determination lines JL1, JL2 are corrected correctly. . Hereinafter, the principle that the corrected optimal number judgment lines JL1 and JL2 are corrected correctly by the correction of the first corrected optimal number judgment line JL1 in the second embodiment will be described. It should be noted that the second corrected optimum number judgment line JL2 is also corrected correctly by the same procedure. Here, as for the first corrected optimum number judgment line JL1, as in the first optimum number judgment line JL, the movement amount in the horizontal axis direction in the generation operation state map is the movement amount in the horizontal axis direction in the operation state map. Will be the same. For this reason, the first corrected optimal number determination line JL1 will be described using the first preliminary corrected optimal number determination line PJL1 used when the first corrected optimal number determination line JL1 is generated.

  Here, similarly to the case shown in FIG. 14, as shown in FIG. 16, it is assumed that the pre-switching COP has changed from the starting point Ph on the second COP curve CL <b> 2 to the position of the assumed movement point Pj. This assumed movement point Pj is on the current first preliminary correction optimum number determination line PJL1, and is a movement target point. The assumed movement point Pj is a position on the side where the capacity load factor of one refrigerator is smaller than the virtual fixed movement point Pi through which the first preliminary correction optimum number judgment line PJL1 passes. In this case, the difference in COP between the starting point Ph and the assumed movement point Pj is approximately 0.39, and a decrease of approximately 5% occurs from the pre-switching COP to the post-switching COP. In FIG. 16, in order to clearly explain the numerical relationship, there are cases in which the positional relationship between the points is shifted from the actual one.

  Further, as in the case shown in FIG. 14, it is assumed that the actual first COP curve is an assumed first COP curve ImaCL1 having a synthesized COP lower than that of the first COP curve CL1.

  In this case, if the actual first COP curve is in the correct state with CL1, the number of operating units should be switched from two to one and become the post-switching assumed movement point Pk. However, the actual moving point Pl that is the actual moving point has a lower combined COP than the post-switching assumed moving point Pk. It is considered that the assumed first COP curve ImaCL1 passes through this actual moving point Pl. Here, the difference in the combined COP between the post-switching assumed movement point Pk and the actual movement point Pl is 0.4, the same as in FIG.

  For this reason, the difference in the synthesized COP between the assumed first COP curve ImaCL1 and the second COP curve CL2 is the difference in the synthesized COP between the assumed moving point Pk after switching and the assumed moving point Pj (in this case, 0.41). Search for the same position. At this time, the first preliminarily corrected optimum number judgment line PJL1 on the second COP curve CL2 passes (hereinafter referred to as “PJL1 point”) Pm, and one refrigerator same as the PJL1 point Pm on the assumed first COP curve ImaCL1 A line connecting the assumed point Pn that becomes the capacity load factor is set. Here, if the movement of the JL1 point on the corrected optimum number judgment line is approximated by horizontal movement, the PJL1 point after the movement is the same COP as the assumed movement point Pj on the line connecting the points Pm and Pn. It becomes point Po.

  Here, when the 1st COP curve CL1 and the assumption 1st COP curve ImaCL1 are the same, the change rate of synthetic | combination COP after switching the operating number of refrigerators will increase about 0.3%. Therefore, it is considered that the movement of the first preliminary corrected optimum number judgment line PJL1 should be performed when the combined COP has decreased after switching the number of operating refrigerators.

  For example, when the first COP curve CL1 wants to move to the assumed first COP curve ImaCL1, the synthesized COP after switching the number of operating refrigerators is reduced by about 4.9%. In addition, in FIG. 16, in order to clarify the correspondence of each point, there is a part where the ratio is not constant.

  Here, the difference in the composite COP between the starting point Ph and the post-switching assumed movement point Pk is 0.021. This difference corresponds to an increase rate of about 0.3%. Further, the difference in the synthesized COP between the starting point Ph and the actual moving point Pl is 0.38. This difference corresponds to a reduction rate of about 4.9%.

  In this case, the post-movement PJL1 point Po is on a line connecting the PJL1 point Pm on the second COP curve CL2 and the assumed point Pn on the assumed first COP curve ImaCL1, and the difference between the combined COP of the point Pm and the point Pn is This is the same as the difference 0.41 in the combined COP between the post-switching assumed movement point Pk and the assumed movement point Pj, and the point Pm is a position that allows a reduction in energy saving equivalent to the point Pj. At this time, the difference in the capacity load factor of one refrigerator between the assumed movement point Pj (PJL 1 point before movement) and the PJL 1 point Po after movement is approximately 5.85%. A difference of about 5.85% in the capacity load factor of one refrigerator can be assumed as a necessary movement amount when moving the movement target point of the first preliminary correction optimum number judgment line PJL1.

Here, the movement amount ΔJL1 is calculated by the following equation (14).
ΔJL1 = (ΔCOP ratio−0) / 2 (14)

  When the above equation (14) is used, for example, when the cooling water refrigerator inlet temperature is 25 ° C. and the ΔCOP ratio is 4.9%, the movement amount ΔJL1 is expressed as {ΔCOP ratio (= 4.9) −0} /2=2.45, which is smaller than 5.85 / 2 = 2.93, which is half of the required movement amount of 5.85. Therefore, the movement amount ΔJL1 is an appropriate movement amount.

  Further, when the cooling water refrigerator inlet temperature is 28 ° C. and the ΔCOP ratio is 4.9%, the required movement amount can be assumed to be 6.86. In this case, the movement amount ΔJL1 is {ΔCOP ratio (= 4.9) −0} /2=2.45 from the above equation (14), which is half of the necessary movement amount 6.86 / It becomes smaller than 2 = 3.43. Therefore, the movement amount ΔJL1 is an appropriate movement amount.

  Therefore, the movement amount ΔJL1 of the movement target point on the first preliminary correction optimum number determination line PJL1 can be calculated and set by the above equation (14). By using the equation (14), the movement amount ΔJL1 of the movement target point increases as the ΔCOP ratio increases. For this reason, it can correct so that it may become close to an actual optimal number judgment line. At this time, along with the movement of the first preliminary correction optimum number determination line PJL1, the preliminary optimum number determination line PJL and the second preliminary correction optimum number determination line PJL2 are also moved in parallel by the movement amount ΔJL1. The numerical values “0” and “2” in the above equation (14) can be appropriately set in consideration of the characteristics of the refrigerator system 1 and the like.

The description when calculating the movement amount ΔJL1 so far assumes that the capacity load factor of one refrigerator is relatively small, but assumes that the capacity load factor of one refrigerator is relatively large. You can also In this case, the movement amount ΔJL2 can be obtained by the following equation (15) in the same manner as the movement amount ΔJL1.
ΔJL2 = (ΔCOP ratio−0) / 2 (15)

  By this equation (15), the movement amount ΔJL2 of the movement target point on the second preliminary correction optimum number judgment line PJL2 can be calculated and set. Also by using the above equation (15), it can be corrected to be close to the actual optimum number judgment line JL. Further, along with the movement of the second preliminary correction optimum number judgment line PJL2, the preliminary optimum number judgment line PJL and the first preliminary correction optimum number judgment line PJL1 are also moved in parallel by the movement amount ΔJL2. Further, the numerical values “0” and “2” in the above equation (15) can be appropriately set in consideration of the characteristics of the refrigerator system 1 and the like.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the number of refrigerators to be operated is determined assuming two refrigerators, but when using three or more refrigerators, the same optimum number judgment line is used. The number of operating units can be determined. When there are three or more refrigerators, for example, an optimum number judgment line between one and two units and an optimum number judgment line between two and three units are determined. It can also be set as the aspect which sets a line. In this case, the first number of the present invention is one and two, the second number is two and three, and there are a plurality of first and second numbers. Further, when the number of operating refrigerators increases, the first number and the second number may increase in the same manner.

  Further, in the above embodiment, 5% is set as the predetermined value for the energy saving reduction used when determining the non-switching range to be set in the optimum number determination line JL, but other numerical values may be used. At this time, it is preferable to set the predetermined value corresponding to the energy saving performance in the range of 1 to 10%. Furthermore, in the above embodiment, the optimum number determination line JL is set to a constant value. However, for example, a predetermined value corresponding to a decrease in energy saving performance may be adjusted in accordance with an air conditioning load or other factors. it can.

  Furthermore, in the above embodiment, when setting the switching delay range on the optimal number determination line JL, a predetermined non-switching range is set on the optimal number determination line JL. However, other modes may be adopted. For example, it is possible to set a time delay as the switching delay range of the optimum number determination line JL and switch the number of operating units after a predetermined time has elapsed after the decision point exceeds the optimum number determination line JL. In addition, the non-switching range and the time delay can be used together to obtain the switching delay range of the optimum number determination line JL. The predetermined time here can also be determined in consideration of a decrease in energy saving.

  Further, the optimum number determination line JL in the above embodiment is set based on a theoretical value. For example, past data (for example, one year) is recorded, and the optimum number determination line JL is recorded according to the record. It can also be set as the aspect which corrects. Similarly, a non-switching range and a switching delay range such as a time delay can be corrected based on past data or the like.

  In the above embodiment, the non-switching range of the optimum number determination line JL is set for both the case where the number of operating refrigerators is switched from one to two and the case where the number is switched from two to one. However, it can be set only when the number of operating refrigerators is switched from one to two, or only when the number of refrigerators is switched from two to one. Alternatively, when the number of operating refrigerators switches from one to two, a non-switching range is set, and when switching from two to one, a time delay is set, or conversely, the number of operating refrigerators When switching from two to one, a non-switching range may be set, and when switching from one to two, a time delay may be set.

  Furthermore, in the said embodiment, although the optimal number determination line shown in FIG. 3 is formed on the driving | running state map which makes the horizontal axis the load factor with respect to the capacity | capacitance of 1 refrigerator, and makes the cooling water temperature of the refrigerator vertical axis | shaft. Further, the generation operation state map shown in FIG. 5C may be an operation state map according to the present invention. In this case, the optimum number determination line is formed on the generation operation state map. On the other hand, the present invention may be a program for causing the control device 40 to execute the above-described method for determining the number of operating refrigerators, or a storage medium for storing the program.

DESCRIPTION OF SYMBOLS 1 ... Refrigerator system 10 ... 1st refrigerator 11 ... 1st cooling water piping 12 ... 1st cooling tower 13 ... 1st cooling water piping 14 ... 1st cooling water thermometer 15 ... 1st cooling water pump 16 ... Cold water going temperature Total 17 ... 1st cold water pump 20 ... 2nd refrigerator 21 ... 2nd cooling water piping 22 ... 2nd cooling tower 23 ... 2nd cooling water piping 24 ... 2nd cooling water thermometer 25 ... 2nd cooling water pump 26 ... cold water Return thermometer 27 ... second cold water pump 31 ... first air conditioner 32 ... second air conditioner 33 ... cold water forward header 33A ... cold water forward header flow meter 34 ... cold water return header 34A ... cold water return header flow meter 40 ... control device 41 ... Manufacturing heat quantity calculation part 42 ... Operating number storage part 43 ... Cooling water refrigerator inlet temperature detection part 44 ... Operating state map storage part 45 ... Operating number judgment part 50 ... Control device 51 ... Operating state storage part 52 ... Optimal number judgment line Corrector JL ... Optimal number judgment line JL1 ... 1 modified optimal number decision line JL2 ... second modified optimal number decision line PJL ... preliminary optimum number decision line PJL1 ... first preliminary corrected optimum number decision line PJL2 ... second preliminary corrected optimum number decision line

Claims (15)

A method of determining the number of operating refrigerators for determining the number of operating units among the plurality of refrigerators when performing air conditioning using a plurality of refrigerators,
Generate an operation state map that is a map having an optimum number judgment line that is a judgment criterion for the number of refrigerators whose operation results are relatively large,
A method for determining the number of operating refrigerators, wherein the operating number of the plurality of refrigerators is determined based on whether or not an operating state of the refrigerator exceeds the optimum number judgment line.   2. The operating number of refrigerators according to claim 1, wherein the operating state map is an operating state map for determining the optimum number of units with the load factor relative to the capacity of one refrigerator as a horizontal axis and the cooling water temperature of the refrigerator as a vertical axis. Decision method.   The optimum number determination line is the cooling water temperature when the first number of refrigerators are operated in the optimum number determination line generation operation state map with the load factor relative to the capacity of one refrigerator as the horizontal axis and the operation result as the vertical axis. A line formed by connecting the points at the same temperature between the graph for each and the graph for each cooling water temperature when the second number of refrigerators are operated on the operation state map for determining the optimum number of units. The method for determining the number of operating refrigerators according to claim 2.   When the operating number of the refrigerator is switched, after the switching of the operating number, when the operation result becomes relatively smaller than before the switching, the optimum number judgment line is changed to the direction in which the operating number is switched. The method for determining the number of operating refrigerators according to any one of claims 1 to 3, wherein the operating number is moved. When it is determined to switch the operating number, the point corresponding to the coolant temperature when the operating number is switched in the optimum number determination line is moved in the direction in which the operating number is switched,
The method for determining the number of operating refrigerators according to claim 4, wherein a value for moving the optimum number judgment line is decreased as the operating number of the optimum number judgment line is separated from a cooling water temperature.   The movement amount of the optimal number judgment line is adjusted according to the amount of change in the operating results when the operating number in the optimum number judgment line is switched when the optimum number judgment line is moved. 5. A method for determining the number of operating refrigerators according to 5.   The switching delay range, which is a range for delaying switching of the operating number after the operating state of the refrigerator exceeds the optimal number determining line, is set with respect to the optimal number determining line. The method for determining the number of operating refrigerators according to any one of the above.   The method according to claim 7, wherein the switching delay range is a predetermined non-switching range set in the optimum number determination line.   The method for determining the number of operating refrigerators according to claim 7 or 8, wherein the switching delay range is a range in which a reduction in energy saving after exceeding the optimum number judgment line is within a predetermined value.   The method for determining the number of operating refrigerators according to claim 9, wherein the predetermined value is a numerical value of 1% to 10%.   The method for determining the number of operating refrigerators according to claim 9 or 10, wherein the predetermined value is adjustable.   A program for determining the number of operating refrigerators for causing a computer to execute the method for determining the operating number of refrigerators according to any one of claims 1 to 11.   The computer-readable recording medium which recorded the operating number determination program of the refrigerator of Claim 12. An apparatus for determining the number of operating refrigerators for determining the operating number of the plurality of refrigerators when performing air conditioning using a plurality of refrigerators,
An operation state map storage means for storing an operation state map that is a map having an optimum number determination line that is a criterion for determining the number of refrigerators for which the operation results generated in advance are relatively large;
The operation number determination means for determining the operation number of the plurality of refrigerators according to whether or not the operation state of the refrigerator exceeds the optimum number determination line;
An apparatus for determining the number of operating refrigerators, comprising:   15. The operation number determination of the number of refrigerators according to claim 14, wherein the operation state map is an optimum number determination operation state map in which a horizontal axis represents a load factor with respect to the capacity of one refrigerator and a vertical axis represents a cooling water temperature of the refrigerator. apparatus.

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