JP2021025449A - Cooling system - Google Patents

Abstract

To suppress occurrence of hunting in cooling control.SOLUTION: A cooling system comprises: a primary cooling system which is provided in each of a plurality of heating sources and cools the heating source with a first coolant which is circulated between the heating source and a heat exchanger; a secondary cooling system which is provided commonly in the plurality of heating sources and includes a pump which supplies a second coolant for cooling the first coolant of each of the primary cooling systems, to the heat exchanger; and a control device which selects a primary cooling system based on a temperature of the first coolant and controls output of the pump based on the temperature of the first coolant of the selected primary cooling system. After the lapse of a preset time from the selection of the primary cooling system, the control device newly selects a primary cooling system and controls the output of the pump based on the temperature of the first coolant of the selected primary cooling system.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to cooling systems.

For example, in a cooling system for a heat generating source such as a generator or an engine used in a ship, a primary cooling system that cools the heat generating source itself by fresh water circulating between the heat generating source and the heat exchanger and a heat exchange such as the primary cooling system. It is equipped with a secondary cooling system that cools fresh water such as a primary cooling system by the seawater supplied to the vessel. In the secondary cooling system, the output of the pump that supplies seawater to the heat exchanger is controlled according to the temperature of the fresh water in the primary cooling system.

When a ship is equipped with a plurality of heat sources, a secondary cooling system may be provided in common for each heat source. In this case, if the pump is controlled using the primary cooling system having the highest fresh water temperature as an index among the primary cooling systems provided for each of the plurality of heat sources, the primary cooling system that serves as an index due to the change in the temperature of the fresh water becomes an index. It is possible that it will switch frequently.

For example, when the temperature of the fresh water of the first primary cooling system is an index of control, the temperature of the fresh water of another second primary cooling system is the temperature of the fresh water of the first primary cooling system. When the temperature exceeds, the temperature of fresh water in the second primary cooling system is switched to the control index. Therefore, when there is no difference between the temperature of the fresh water in the first primary cooling system and the temperature of the fresh water in the second primary cooling system, the primary cooling system, which is an index of control, is frequently switched. In this case, hunting occurs under the control of the pump.

Japanese Unexamined Patent Publication No. 2010-269641

An object of the embodiment of the present invention is to suppress the occurrence of hunting in the cooling control of the heat generation source.

In order to solve the above problems, the cooling system according to the embodiment is provided in each of a plurality of heat generation sources, and is a primary cooling that cools the heat generation source with a first refrigerant that circulates between the heat generation source and the heat exchanger. A secondary cooling system having a pump that is provided in common to the system and a plurality of heat generating sources and supplies a second cooling medium for cooling the first refrigerant of each primary cooling system to the heat exchanger, and a first cooling system. The primary cooling system is selected based on the temperature of the selected primary cooling system, and the control device is provided with a control device that controls the output of the pump based on the temperature of the first refrigerant of the selected primary cooling system. Then, after a preset time has elapsed, the primary cooling system is newly selected, and the output of the pump is controlled based on the temperature of the first refrigerant in the selected primary cooling system.

It is a block diagram which shows the structure of the cooling system which concerns on this embodiment. It is a block diagram which shows the control system of a cooling system. It is a flowchart which shows the series of processing executed by PLC. It is a figure which shows the relationship between a temperature difference and a target time. It is a graph which shows the time transition of the temperature of a refrigerant. It is a flowchart which shows the series of processing executed by PLC. It is a graph which shows the time transition of the temperature of a refrigerant. It is a graph which shows the time transition of the moving average temperature of a refrigerant. It is a graph which shows the time transition of the moving average temperature of a refrigerant. It is a graph which shows the time transition of the moving average temperature of a refrigerant.

<< First Embodiment >>
Hereinafter, the first embodiment will be described. FIG. 1 is a block diagram showing a configuration of a cooling system 1 according to the present embodiment. As shown in FIG. 1, the cooling system 1 is a system for cooling a plurality of generators 50 ₁ to 50 _N mounted on, for example, a ship or the like.

The cooling system 1 is a plurality of primary cooling systems 10 ₁ to 10 _{N provided for each of the generators 50 1} to 50 _N , and a secondary cooling system commonly provided for the plurality of primary cooling systems 10 ₁ to 10 _N. 20 and a control device 30 for controlling the output of the secondary cooling system 20 are provided.

Generators 50 ₁ to 50 _N Each is a generator mounted on a ship and functions as a power source in the ship. For convenience of explanation, the generators 50 ₁ to 50 _N and the primary cooling system 10 ₁ to 10 _N are appropriately abbreviated as the generator 50 and the primary cooling system 10.

The primary cooling system 10 is a cooling system that uses tap water or the like as a refrigerant. The primary cooling system 10 has a heat exchanger 11, a circulation system H for circulating a refrigerant between the heat exchanger 11 and the generator 50, and a circulation pump 13 provided in the circulation system H.

The heat exchanger 11 is a device for exchanging heat between the refrigerant of the secondary cooling system 20 and the refrigerant of the primary cooling system 10. The heat exchanger 11 is connected to the generator 50 via the circulation system H.

The circulatory system H is composed of pipes H1 to H3. The pipes H1 and H2 are provided over the heat exchanger 11 and the generator 50, respectively. A temperature control valve 12 is provided in the pipe H1, and a circulation pump 13 is provided in the pipe H2. Further, the pipe H2 is provided with a pipe H3 that branches from the intermediate portion. The pipe H3 branching from the pipe H2 is connected to the temperature control valve 12.

In the primary cooling system 10 configured as described above, the circulation pump 13 is activated when the generator 50 is activated. When the circulation pump 13 is started, the refrigerant circulates between the generator 50 and the heat exchanger 11 via the pipes H1 and H2. Further, when the temperature of the refrigerant passing through the heat exchanger 11 is low, a part of the refrigerant flowing through the pipe H1 is supplied to the temperature control valve 12 via the pipe H3. In this case, in the temperature control valve 12, the low temperature refrigerant cooled by the heat exchanger 11 and the high temperature refrigerant supplied to the temperature control valve 12 via the pipe H3 without going through the heat exchanger 11 are mixed. To. By mixing the low temperature refrigerant and the high temperature refrigerant in the temperature control valve 12, the temperature of the refrigerant flowing from the temperature control valve 12 to the generator 50 is maintained at a constant value. Cooling of the generator 50 is realized by circulating the temperature-controlled refrigerant through the generator 50 as a heat generating source.

The secondary cooling system 20 is, for example, a cooling system that uses seawater outside the ship as a refrigerant. The secondary cooling system 20 has a circulation system L and a seawater pump 21 provided in the circulation system L. In the circulatory system L, a water absorption pipe L1 for pumping seawater from the sea, a drainage pipe L2 for draining seawater into the sea, and _{heat exchangers 11 constituting each primary cooling system 10 1} to 10 _N are connected in series. It is composed of a connecting pipe L3. Further, the water absorption pipe L1 is provided with a seawater pump 21.

In the secondary cooling system 20 configured as described above, when the seawater pump 21 is operated by the control device 30, seawater circulates in the circulation system L. In the circulatory system L, seawater is pumped through the water absorption pipe L1. Then, the pumped seawater exchanges heat with the refrigerant of _{each primary cooling system 10 1} to 10 _N while passing through the heat exchanger 11 of _{each primary cooling system 10 1} to 10 _{N in order.} As a result, the refrigerant of each primary cooling system 10 ₁ to 10 _{N is cooled.} The seawater that has passed through the heat exchangers 11 of each primary cooling system 10 ₁ to 10 _N in order is drained into the sea through the drain pipe L2.

The control device 30 is a device for driving the seawater pump 21 of the secondary cooling system 20 based on the temperature of the refrigerant of the _{primary cooling system 10 1} to 10 _N. FIG. 2 is a block diagram showing a control system of the cooling system 1. As shown in FIG. 2, the control device 30 includes a PLC (Programmable Logic Controller) 31 and a drive unit 32.

The PLC 31 includes a CPU (Central Processing Unit), a main storage unit that functions as a work area of the CPU, an auxiliary storage unit that stores control programs executed by the CPU and various parameters, and an interface to which sensors and other devices are connected. It is a computer to have. _{Temperature sensors 14 1 to} 14 _N and a drive unit 32 are connected to the interface of the PLC 31.

Each of the temperature sensors 14 _{1 to} 14 _N is a sensor including, for example, a thermoelectric pair, and is provided in the heat exchanger 11 as shown in FIG. Each of the temperature sensors 14 _{1 to} 14 _N shows a resistance value according to the temperature of the refrigerant of the primary cooling system 10 cooled by the heat exchanger 11, for example. The temperatures detected by the temperature sensors 14 _{1 to} 14 _N are T1 to TN, respectively.

The drive unit 32 includes an inverter that utilizes the electric power from the generator 50. The drive unit 32 operates the seawater pump 21 with an output according to the instruction of the PLC 31. In the seawater pump 21, seawater is discharged at a flow rate corresponding to the output.

Next, the operation of the cooling system 1 configured as described above will be described with reference to the flowchart of FIG. The series of processes shown in the flowchart is executed by the PLC 31 according to the control program. The series of processes shown in the flowchart is started, for example, _{when any one of} the generators 50 1 to 50 _N is operated. Further, for convenience of explanation, it is assumed that the number of generators 50 is 3 (N = 3).

First, the PLC 31 determines whether or not the seawater pump 21 is operating (step S101). When the PLC 31 determines that the seawater pump 21 is not operating (step S101: No), the PLC 31 instructs the drive unit 32 to operate the seawater pump (step S102). As a result, the seawater pump 21 is started by the drive unit 32. The output of the seawater pump 21 at this time is, for example, an output commensurate with the operating generator 50 among the _{three generators 50 1} to 503. For example, according to the target cooling temperature K1, K2, K3 of the power generator ₅₀ 1-50 _3, when the output of the seawater pump 21 is defined as P1, P2, P3, the generator 50 ₁ is running Occasionally, the output of the seawater pump 21 is P1. Similarly, when the generator ₅₀ 2, 50 ₃ is operating, the output of the seawater pump 21 becomes P2, P3. Output P1, P2, P3, for example, an output corresponding to the temperature, etc. of each generator ₅₀ 1-50 primary cooling system ₁₀ 1 to 10 ₃ of the refrigerant is provided in _3.

Further, when all the generators 50 are in operation, the seawater pump 21 is operated with a predetermined output.

Next, the PLC 31 compares the temperatures T1, T2, and T3 of the refrigerants of the primary cooling systems 10 ₁ to 10 _{3 via the temperature sensors 14 1 to} 14 _{3 (step S103).} Then, the PLC 31 determines whether or not the temperature T1 is the maximum (step S104). When the PLC 31 determines that the temperature T1 is the maximum (step S104: Yes), the PLC 31 instructs the drive unit 32 to operate the seawater pump 21 at the output P1. As a result, the output of the seawater pump 21 is set to P1 (step S105). When the output of the seawater pump 21 is set to P1, at output suitable for cooling of the refrigerant in the primary cooling system 10 _1, sea water pump 21 is operated.

Next, the PLC _{31 monitors the temperatures T1 to T3 of the refrigerants of the primary cooling systems 10 1} to 10 ₃ and determines whether or not the temperature T2 or the temperature T3 is higher than the temperature T1 (step S106). When the PLC 31 determines that the temperature T2 or the temperature T3 is equal to or lower than the temperature T1 (step S106: No), the PLC 31 continues to monitor the temperatures T1 to T3 of the refrigerants of _{the respective primary cooling systems 10 1} to 10 _3. On the other hand, when the PLC 31 determines that the temperature T2 or the temperature T3 is higher than the temperature T1 (step S106: Yes), the PLC 31 starts the timer (step S107).

Next, the PLC 31 determines whether or not the timer value TIME is equal to or greater than the target time TM1 (step S108). The target time TM1 is determined based on, for example, the temperature difference ΔT (= TN-TTN) between the cooling target temperatures TT1 to TT3 of the refrigerant of the _{primary cooling system 10 1} to 10 _{3 and the current temperatures T1 to T3 of the refrigerant.} Can be considered. For example, FIG. 4 is a diagram showing the relationship between the temperature difference ΔT and the target time TM1. As shown in FIG. 4, when the temperature difference ΔT is small, the target time TM1 is increased, and when the temperature difference ΔT is large, the target time TM1 is decreased.

For example, in step S108, the target time TM1 is determined based on the largest temperature difference ΔT among the temperature differences ΔT obtained by the calculations of T1-TT1, T2-TT2, and T3-TT3. The relationship between the temperature difference ΔT shown in FIG. 4 and the target time TM1 may be determined by the output of the generator 50 or the like.

When the PLC 31 determines that the timer value TIME is equal to or longer than the target time TM1 (step S108: Yes), the PLC 31 returns to step S104 and executes the processes after step S104.

On the other hand, when it is determined in step S104 that the temperature T1 is not the maximum (step S104: No), the PLC 31 determines whether or not the temperature T2 is the maximum (step S109). When the PLC 31 determines that the temperature T2 is the maximum (step S109: Yes), the PLC 31 instructs the drive unit 32 to operate the seawater pump 21 at the output P2. As a result, the output of the seawater pump 21 is set to P2 (step S110). When the output of the seawater pump 21 is set to P2, the output suitable for the cooling of the refrigerant in the primary cooling system 10 _2, seawater pump 21 is operated.

Next, the PLC _{31 monitors the temperatures T1 to T3 of the refrigerants of the primary cooling systems 10 1} to 10 ₃ and determines whether or not the temperature T1 or the temperature T3 is higher than the temperature T2 (step S111). When the PLC 31 determines that the temperature T1 or the temperature T3 is equal to or lower than the temperature T2 (step S111: No), the PLC 31 continues to monitor the temperatures T1 to T3 of the refrigerants of _{the respective primary cooling systems 10 1} to 10 _3. On the other hand, when the PLC 31 determines that the temperature T1 or the temperature T3 is higher than the temperature T2 (step S111: Yes), the PLC 31 starts the timer (step S107). Then, the PLC 31 determines whether or not the timer value TIME is equal to or greater than the target time TM1 (step S108), and if it determines that the timer value TIME is equal to or greater than the target time TM1 (step S108:). Yes), the process returns to step S104, and the processes after step S104 are executed.

Further, when the PLC 31 determines in step S109 that the temperature T2 is not the maximum (step S109: Yes), the PLC 31 instructs the drive unit 32 to operate the seawater pump 21 at the output P3. As a result, the output of the seawater pump 21 is set to P3 (step S112). When the output of the seawater pump 21 is set to P3, the output suitable for the cooling of the refrigerant in the primary cooling system 10 _3, the seawater pump 21 is operated.

Next, the PLC _{31 monitors the temperatures T1 to T3 of the refrigerants of the primary cooling systems 10 1} to 10 ₃ to determine whether the temperature T1 or the temperature T2 is higher than the temperature T3 (step S113). When the PLC 31 determines that the temperature T1 or the temperature T2 is equal to or lower than the temperature T3 (step S113: No), the PLC 31 continues to monitor the temperatures T1 to T3 of the refrigerants of _{the respective primary cooling systems 10 1} to 10 _3. On the other hand, when it is determined that the temperature T1 or the temperature T2 is higher than the temperature T3 (step S113: Yes), the PLC 31 activates the timer (step S107). Then, the PLC 31 determines whether or not the timer value TIME is equal to or greater than the target time TM1 (step S108), and if it determines that the timer value TIME is equal to or greater than the target time TM1 (step S108:). Yes), the process returns to step S104, and the processes after step S104 are executed.

As described above, after the seawater pump 21 is operated, the processes of steps S104 to S113 are repeatedly executed.

As described above, in the present embodiment, the temperatures of the refrigerants of the _{primary cooling system 10 1} to 10 _{N are compared (step S103).} Then, the temperature of the hottest refrigerant is selected as an index (steps S104 and S108), and the seawater pump 21 is operated with an output suitable for cooling _{the selected primary cooling system 10 1} to 10 _{N (steps S104 and S108).} Steps S105, S110, S112). Next, the temperature of the refrigerant in each primary cooling system 10 ₁ to 10 _N was monitored (steps S106, S111, S113), and the hottest refrigerant was changed to the refrigerant in _{the other primary cooling system 10 1} to 10 _N. Occasionally, after waiting for a predetermined time (target time TM1) (step S108), the temperature of the refrigerant having the highest temperature is sequentially selected as an index (steps S104, S108). Therefore, the control index of the secondary cooling system 20 does not switch in a cycle shorter than the target time TM1. Therefore, it is possible to suppress the occurrence of hunting in the control of the seawater pump 21 constituting the secondary cooling system 20.

5, as an example, a diagram showing the curves S1, S2 representing the transition of the temperature of the refrigerant used in the primary cooling system ₁₀ 1, 10 _2. As can be seen with reference to FIG. 5, when _{the temperatures T1 to TN} of the refrigerant of the _{primary cooling system 10 1} to 10 N are almost equal, due to factors such as the accuracy _{of the temperature sensors 14 1 to} 14 _{N and the output error,} The hottest refrigerant is frequently replaced. In such a case, in the present embodiment, since the control index of the secondary cooling system 20 is suppressed from being frequently switched, the occurrence of hunting in the control of the seawater pump 21 can be effectively suppressed.

Further, as shown in FIG. 4, the target time TM1 includes a temperature T1~TN refrigerant of each primary cooling system ₁₀ 1 to 10 _N, the cooling target temperature TT1~ of the refrigerant in each primary cooling system ₁₀ 1 to 10 _N Determined based on the difference from TTN. Therefore, when the temperature of the refrigerant is significantly higher than the target cooling temperature, the target time TM1 is set small and the control index is switched in a short time. Therefore, the operation of the seawater pump 21 can be switched to the operation corresponding to the _{primary cooling system 10 1 to 10 N in which the temperature of the refrigerant is high in a short time.} On the other hand, when the temperature of the refrigerant is slightly higher than the target cooling temperature, the target time TM1 is set longer and the switching of the control index is suppressed in a short time. Therefore, it is possible to appropriately switch the control index while suppressing hunting.

<< Second Embodiment >>
Next, the second embodiment will be described with reference to the drawings. For the same or equivalent configuration as that of the first embodiment, the same reference numerals are used, and the description thereof will be omitted or simplified. In the cooling system 1 according to the present embodiment, the series of processes performed by the PLC 31 is partially different from the processes according to the first embodiment.

FIG. 6 is a flowchart showing a series of processes executed by the PLC 31. First, the PLC 31 determines whether or not the seawater pump 21 is operating (step S201). When the PLC 31 determines that the seawater pump 21 is not operating (step S201: No), the PLC 31 instructs the drive unit 32 to operate the seawater pump (step S202). As a result, the seawater pump 21 is started by the drive unit 32. The output of the seawater pump 21 at this time can be arbitrarily set. Here, the output of the seawater pump 21, for example, an output P1 commensurate with the power generator 50 _one of the generator ₅₀ 1-50 ₃ the three (step S203).

Next, the PLC 31 calculates the moving average temperatures A2 and A3 of the refrigerant temperatures T2 and T3 of the _{primary cooling systems 10 2 and} 10 _{3 (step S204).} The time interval when calculating the moving average temperature is, for example, about several times the sampling period SP of the temperatures T1 to T3.

For example, FIG. 7 is a graph showing a change in the temperature T2, which is sampled by the sensor 14 _2. As shown in FIG. 7, the measured temperature T2 fluctuates due to a measurement error, an output error, or the like. Therefore, the temperature T2 may have a microscopic variation in magnitude with respect to the actual temperature. Therefore, the PLC 31 calculates, for example, the average value of the measured values of the latest several points as the moving average temperature A2 for each sampling cycle SP.

8 to 10 are diagrams showing, for example, the curve SA2 showing the transition of the moving average temperature A2. When sea water pump 21, when it is operated at the output P1 in accordance with the target cooling temperature K1 of the generator 50 _1, the output P1 is equal to the output P2 in response to the target cooling temperature K2 of the generator 50 ₂ the generator 50 ₂ is also proper cooling. In this case, as shown in FIG. 8, the moving average temperature A2 changes in a state of converging to a constant value. Further, the output P1 is the case above the output P2 in accordance with the target cooling temperature K2 of the generator 50 _2, the generator 50 ₂ is sufficiently cooled. In this case, as shown in FIG. 9, the moving average temperature A2 changes toward a constant temperature so as to decrease with time.

On the other hand, when the output P1 is below the output P2 in accordance with the target cooling temperature K2 of the generator 50 _2, cooling the generator 50 ₂ becomes insufficient. In this case, as shown in FIG. 10, the moving average temperature A2 changes toward a constant temperature so as to rise with time.

As shown in the graphs of FIGS. 8 and 9, when the moving average temperature A2 is maintained constant or decreases, it is not necessary to change the output of the seawater pump 21. However, as shown in the graph of FIG. 10, when the moving average temperature A2 rises, it is necessary to increase the output of the seawater pump 21.

Therefore, the PLC 31 first determines whether or not the moving average temperature A2 of the refrigerant temperature T2 of the primary cooling system 10 _{2 different from the primary cooling system 10 1 continues to exceed the threshold Th2 for a time ST.} (Step S205).

Threshold Th2 is a value determined according to the specifications of the generator 50 _2, for example, is set to a temperature slightly lower than the allowable maximum temperature of the water temperature of the primary cooling system 10 _2. Further, the predetermined time ST is set within the range of, for example, several seconds to several tens of seconds.

PLC31, as shown in FIGS. 8 and 9, when the moving average temperature A2 is state exceeds the threshold Th2 is determined to not time ST continued (step S205: No), the primary cooling system 10 ₃ refrigerant It is determined whether or not the state in which the moving average temperature A3 of the temperature T3 of the above temperature exceeds the threshold value Th3 continues for a time ST (step S206). The threshold Th3 is set to, for example, a temperature slightly lower than the allowable maximum temperature of the water temperature of the primary cooling system 10 _3.

When it is determined that the state in which the moving average temperature A3 exceeds the threshold value Th3 does not continue for the time ST (step S206: No), the PLC 31 repeatedly executes the processes of steps S204 to S206.

On the other hand, in the process of step S205, as shown in FIG. 10, when the PLC 31 determines that the state in which the moving average temperature A2 exceeds the threshold Th2 continues for a time ST (step S205: Yes), the seawater pump 21 The output of is set to the output P2 (step S207). When the output of the seawater pump 21 is set to the output P2, an output suitable for the cooling of the refrigerant in the primary cooling system 10 _2, seawater pump 21 is operated.

Next, the PLC 31 calculates the moving average temperatures A1 and A3 of the refrigerant temperatures T1 and T3 of the _{primary cooling systems 10 1,} 10 _{3 (step S208).} Then, the PLC 31 first determines whether or not the moving average temperature A3 of the refrigerant temperature T3 of the primary cooling system 10 _{3 different from the primary cooling system 10 2 continues to exceed the threshold value Th3 for a time ST.} (Step S209).

PLC31 moving average temperature A3 is, when the state exceeds the threshold value Th3 is determined to not time ST continued: the moving average temperature A1 in (step S209 No), the primary cooling system 10 _first temperature T1 of the refrigerant, the threshold It is determined whether or not the state exceeding Th1 continues for the time ST (step S210). The threshold value Th1 is set to, for example, a temperature slightly lower than the allowable maximum temperature of the water temperature of the primary cooling system 10 _1.

When it is determined that the state in which the moving average temperature A1 exceeds the threshold Th1 does not continue for the time ST (step S210: No), the PLC 31 repeatedly executes the processes of steps S208 to S210.

On the other hand, in the process of step S209, when the PLC 31 determines that the state in which the moving average temperature A3 exceeds the threshold Th3 continues for a time ST (step S209: Yes), the PLC 31 sets the output of the seawater pump 21 to the output P3. (Step S211). When the output of the seawater pump 21 is set to the output P3, with output suitable for cooling of the refrigerant in the primary cooling system 10 _3, the seawater pump 21 is operated.

Next, PLC 31 calculates a moving average temperature A1, A2 of the temperatures T1, T2 of each primary cooling system ₁₀ 1, 10 ₂ of the refrigerant (step S212). Then, PLC 31 is first moving average temperature A2 of the primary cooling system 10 ₃ temperature T2 of another primary cooling system 10 ₂ of the refrigerant between the state in which exceeds the threshold value Th2 to determine whether the time ST continued (Step S213).

PLC31 moving average temperature A2 is, when the state exceeds the threshold Th2 is determined to not time ST continued: the moving average temperature A1 in (step S213 No), the primary cooling system 10 _first temperature T1 of the refrigerant, the threshold It is determined whether or not the state exceeding Th1 continues for the time ST (step S214).

When it is determined that the state in which the moving average temperature A1 exceeds the threshold Th1 does not continue for the time ST (step S214: No), the PLC 31 repeatedly executes the processes of steps S212 to S214.

On the other hand, in the process of step S213, when the PLC 31 determines that the state in which the moving average temperature A2 exceeds the threshold Th2 continues for a time ST (step S213: Yes), the PLC 31 sets the output of the seawater pump 21 to the output P2. (Step S207). Then, the processes after step S207 are executed.

Further, the PLC3 determines that the state in which the moving average temperature A1 exceeds the threshold Th1 continues for a time ST in the process of step S210 (step S214: Yes), or the moving average temperature in the process of step S214. When it is determined that the state in which A1 exceeds the threshold Th1 continues for a time ST (step S214: Yes), the output of the seawater pump 21 is set to the output P1 (step S203). Then, the processes after step S203 are executed.

As described above, in the present embodiment, when the seawater pump 21 is operated with an output commensurate with the generator 50 to be cooled among the plurality of generators 50 (steps S203, S207, S211), the rest. The moving average temperatures A1 to A3 of the primary cooling system 10 of the generator 50 of the above are calculated. Then, when the moving average temperatures A1 to A3 tend to rise, the output of the seawater pump 21 is increased to an output commensurate with the generator 50 whose moving average temperature tends to rise.

As described above, the moving average temperatures A1 to A3 have little variation in values due to factors such as the accuracy of the temperature sensor and the output error, and the magnitude relationship is rarely changed frequently. _{Therefore, it is possible to select the primary cooling system 10 1} to 10 _N to be cooled at an appropriate timing and suppress the occurrence of hunting in the control of the seawater pump 21 constituting the secondary cooling system 20.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiment, the case where the heat generating source is the generator 50 has been described. Not limited to this, the heat generation source may be a prime mover or the like.

In the above embodiment, the refrigerant of the secondary cooling system 20 is seawater. Not limited to this, the refrigerant of the secondary cooling system 20 may be lake water, tap water, or the like. Similarly, the refrigerant of the primary cooling system 10 ₁ to 10 _N is not limited to tap water.

In the above embodiment, the case where the generator 50 is mounted on the ship has been described. Not limited to this, the generator 50 may be mounted on land equipment.

In the above embodiment, the primary cooling system 101 to _{10 N} having the highest refrigerant temperature is selected, and the output of the seawater pump 21 is set according to the _{selected primary cooling system 10 1} to 10 N (step S104). , S109). Not limited thereto, and the threshold _Th2 1 _{~Th2 N} set for each primary cooling system ₁₀ 1 to 10 _N of the generator ₅₀ 1 to 50 _N, the primary cooling system the difference between the temperature T1~TN refrigerant is maximized 10 ₁ to 10 _N may be selected and the output of the seawater pump 21 may be set according to the selected primary cooling system 10 ₁ to 10 _N. In this case, in steps S104 and S109, ΔT1 (= T1-Th2 ₁ ), ΔT2 (= T2-Th2 ₂ ), and ΔT3 (= T3-Th2 ₃ ) are compared with each other, and in step S104, ΔT1 Is the maximum or not, and in step S109, it may be determined whether or not ΔT2 is the maximum.

According to this, even when the cooling target temperatures of the _{generators 50 1} to 50 _{N are different, the generators 50 1} to 50 _N can be cooled in just proportion.

Although embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other embodiments and can be omitted, replaced or modified in various ways without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the present invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Cooling system 10 Primary cooling system 11 Heat exchanger 12 Temperature control valve 13 Circulation pump 20 Secondary cooling system 21 Seawater pump 30 Control device 31 PLC
32 Drive unit 50 Generator 10 Primary cooling system 14 Temperature sensor H Circulation system H1 to H3 Piping L1 Water absorption pipe L2 Drain pipe L3 Connection pipe

In order to solve the above problems, the cooling system according to the embodiment is provided in each of the plurality of heat sources, and a plurality of cooling sources are cooled by a first refrigerant circulating between the heat sources and the heat exchanger. a primary cooling system is provided in common to a plurality of heat sources, and a second secondary cooling system comprises a pump for supplying coolant for cooling the first refrigerant of each primary cooling system to the heat exchanger, a plurality of Select one primary cooling system from multiple primary cooling systems based on the temperature of the first refrigerant in each primary cooling system and output the pump output based on the temperature of the first refrigerant in the selected primary cooling system. a control device for controlling, Ru comprising a. The control device selects one of the plurality of primary cooling systems, and after a lapse of a preset time, again, based on the temperature of the first refrigerant of each of the plurality of primary cooling systems. The primary cooling system is newly selected, and the output of the pump is controlled based on the temperature of the first refrigerant of the newly selected primary cooling system.

Claims (6)

A primary cooling system that cools the heat source with a first refrigerant that is provided in each of the plurality of heat sources and circulates between the heat source and the heat exchanger.
A secondary cooling system that is provided in common to the plurality of heat sources and includes a pump that supplies a second refrigerant that cools the first refrigerant of each of the primary cooling systems to the heat exchanger.
A control device that selects the primary cooling system based on the temperature of the first refrigerant and controls the output of the pump based on the temperature of the first refrigerant in the selected primary cooling system.
With
The control device is
After a preset time has elapsed since the primary cooling system was selected, the primary cooling system is newly selected, and the pump is based on the temperature of the first refrigerant in the selected primary cooling system. A cooling system that controls the output of. The cooling system according to claim 1, wherein the control device selects the primary cooling system having the highest temperature of the first refrigerant. The cooling system according to claim 1, wherein the control device selects the primary cooling system in which the difference between the temperature of the first refrigerant and the threshold value provided for each primary cooling system is the largest. A primary cooling system that cools the heat source with a first refrigerant that is provided in each of the plurality of heat sources and circulates between the heat source and the heat exchanger.
A secondary cooling system that is provided in common to the plurality of heat sources and includes a pump that supplies a second refrigerant that cools the first refrigerant of each of the primary cooling systems to the heat exchanger.
A control device that selects the primary cooling system based on the moving average of the temperature rise of the first refrigerant and controls the output of the pump based on the temperature of the first refrigerant in the selected primary cooling system. ,
Cooling system with. The cooling system according to claim 4, wherein the control device selects the primary cooling system in which the moving average of the temperature rise of the first refrigerant changes above the threshold value for a predetermined period. The cooling system according to claim 4 or 5, wherein the threshold value is set according to the capacity of the plurality of heat sources.

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