WO2012173240A1 - Heat source system and control method of same - Google Patents

Abstract

Provided is a heat source system (100) including a cooling water system which is configured such that cooling water cooled by a cooling tower (1) circulates, a cool water system which is configured such that cool water cooling a load side (3) circulates, a high temperature side refrigerator (2a) and a low temperature side refrigerator (2b) which are configured to be disposed in series in the cool water system and cool cool water, and a control device (71) which is configured to control a cooling fan (6) of the cooling tower (1), a high temperature side cooling water pump (4a), a low temperature side cooling water pump (4b), and a cool water pump (5) as objects to be controlled, wherein cool water is supplied to the load side (3) through a heat storage tank (8) storing the cool water. The control device (71) sets target control values of the objects to be controlled such that an evaluation function indicating energy consumption is minimized in response to change in at least one of external air condition, a heat storage amount of the heat storage tank (8), and a required load of the load side (3).

Description

Heat source system and control method thereof

The present invention relates to a heat source system and a control method thereof.

A heat source system that manufactures cold water with a refrigerator and cools a load side (room or device) with the cold water is widely known. The refrigerator provided in such a heat source system is controlled with a capacity corresponding to the increase or decrease of the load on the load side.
There is also a heat source system in which two or more refrigerators are arranged in series so that the temperature difference of cold water used for cooling can be increased to reduce the conveyance power (for example, see Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 61-225528 Japanese Patent Laid-Open No. 60-23760

The heat source system disclosed in Patent Documents 1 and 2 has a large temperature difference (temperature difference between the inlet side and the outlet side of the refrigerator) in the return of the chilled water temperature fed to the load side, for example, in an area where the outside air temperature is high. In this case, the chiller pump power can be reduced by increasing the temperature difference by arranging the refrigerator arranged on the high temperature side and the refrigerator arranged on the low temperature side in series.
However, when the refrigerators are arranged in series, when the flow rate of the pump for feeding cold water to the refrigerator is constant, the efficiency is reduced when the cooling load is small compared to the load near the maximum capacity (maximum load). There is a problem in that the efficiency of the heat source system is lowered in accordance with changes in the load to be cooled (load side) and the outside air state. Moreover, it is necessary to cope with the load change in consideration of the heat storage amount of the heat storage tank in which the cold water is stored.

Therefore, an object of the present invention is to provide a heat source system and a control method thereof that can improve the efficiency when the refrigerators arranged in series are not operated at the maximum load.

In order to solve the above problems, the present invention provides a first chilled water system in which the first chilled water cooled by the cooling tower circulates, a second chilled water system in which the second chilled water for cooling the load side circulates, and the second A plurality of refrigerators arranged in series in a chilled water system and transferring heat of the second chilled water that has cooled the load side to the first chilled water to cool the second chilled water, and at least the cooling tower A cooling fan that blows outside air, a first pump that circulates the first cold water, and a control device that controls a second pump that circulates the second cold water as an object to be controlled. The heat source system is configured such that the second cold water is supplied via a heat storage unit that stores the second cold water cooled by the refrigerator. And the said control apparatus respond | corresponds to at least 1 change of the state of external air, the thermal storage amount of the said thermal storage means, and the load side demand load, so that the evaluation function indicating the energy consumption is minimized A control target value to be controlled is set.

According to the present invention, it is possible to provide a heat source system and its control method that can improve the efficiency when the refrigerators arranged in series are not operated at the maximum load.

It is a figure showing an example of 1 composition of a heat source system concerning this embodiment. (A) is a graph showing the relationship between the load factor of the refrigerator and the COP when the control target value of the control target is constant, and (b) is the control target value of the control target set based on the optimization calculation. It is a graph which shows the relationship between the load factor of a refrigerator, and COP in the case. It is a flowchart which shows the procedure of a thermal storage driving | operation. (A) is a graph which shows an example of the fluctuation | variation of the cooling amount when a refrigerator is drive | operated by the refrigerator load which becomes 100% of cooling amount in a thermal storage time slot | zone, (b) is a cooling amount for every hour. It is a graph which shows the state which became less than 100% and energy consumption decreased. It is a flowchart which shows the procedure which performs a thermal storage driving | operation and a cooling driving | operation according to the load by the side of a load. It is a figure which shows an example of the data table which shows the relationship between the wet bulb temperature of external air, the load factor of a refrigerator, and the rotational speed ratio of a cooling water pump. It is a figure which shows the structural example of the heat source system by which a high temperature side refrigerator and a low temperature side refrigerator are arrange | positioned in series by a cooling water system | strain. It is a figure which shows the structural example of a heat source system provided with two cooling towers.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the heat source system 100 according to the present embodiment includes a first cold water system (cooling water system) in which first cold water (cooling water) cooled by free cooling in the cooling tower 1 circulates, A second cold water system (cold water system) in which the second cold water (cold water) for cooling the load side 3 circulates is configured to be thermally connected by the high temperature side refrigerator 2a and the low temperature side refrigerator 2b. The high temperature side refrigerator 2a and the low temperature side refrigerator 2b are turbo refrigerators, for example, and are arranged in series in the cold water system.
And the heat of the cold water which cooled the load side 3 and heated up moves to a cooling water with the high temperature side refrigerator 2a and the low temperature side refrigerator 2b, and it is comprised so that cold water may be cooled.
In addition, the high temperature side refrigerator 2a is arrange | positioned upstream with respect to the flow of the cold water in a cold water system | strain, and the low temperature side refrigerator 2b is arrange | positioned downstream.

In the cooling water system, a high temperature side cooling water pump 4a and a high temperature side refrigerator 2a are arranged in a cooling water outgoing pipe 61a connected to the outlet side of the cooling tower 1, and the cooling water cooled by the cooling tower 1 is on the high temperature side. It is sent into the high temperature side refrigerator 2a by the cooling water pump 4a. The outlet side of the high temperature side refrigerator 2a is connected to the inlet side of the cooling tower 1 by a cooling water return pipe 62a so that the cooling water flowing out from the high temperature side refrigerator 2a flows into the cooling tower 1.

Further, a branch outgoing pipe 61b is connected to the cooling water outgoing pipe 61a between the outlet side of the cooling tower 1 and the high temperature side cooling water pump 4a. The branch outgoing pipe 61b is provided with a low temperature side cooling water pump 4b and a low temperature side refrigerator 2b, and a part of the cooling water cooled by the cooling tower 1 is sent to the low temperature side refrigerator 2b by the low temperature side cooling water pump 4b. It is. A branch return pipe 62b is connected to the outlet side of the low temperature side refrigerator 2b, and the branch return pipe 62b is connected to the cooling water return pipe 62a between the outlet side of the high temperature side refrigerator 2a and the inlet side of the cooling tower 1. Is done.
That is, the high temperature side refrigerator 2a and the low temperature side refrigerator 2b are arranged in parallel in the cooling water system. In this embodiment, the high temperature side cooling water pump 4a and the low temperature side cooling water pump 4b are combined to form a first pump.

The cooling tower 1 is provided with a cooling fan 6 driven by an inverter 51, and the cooling water flowing into the cooling tower 1 is cooled by outside air blown by the cooling fan 6. The rotation speed of the cooling fan 6 is controlled by controlling the frequency input to the inverter 51.
That is, by controlling the frequency input to the inverter 51, the amount of air blown to the cooling tower 1 is controlled.

The high temperature side cooling water pump 4a is driven by an inverter 52a, and the low temperature side cooling water pump 4b is driven by an inverter 52b. A cooling tower outlet temperature sensor 31 that measures the outlet temperature of the cooling water in the cooling tower 1 (cooling tower outlet cooling water temperature) is disposed on the outlet side of the cooling tower 1.
The high temperature side cooling water pump 4a and the low temperature side cooling water pump 4b are controlled in rotation speed by controlling the frequencies input to the inverters 52a and 52b, respectively.
That is, the flow rate of the cooling water in the cooling water system is controlled by controlling the frequency input to the inverters 52a and 52b.

In the cold water system, the outlet side of the heat storage tank 8 and the inlet side of the high temperature side refrigerator 2a are connected by a cold water return pipe 64 in which the cold water pump 5 is disposed, and further, the outlet side of the high temperature side refrigerator 2a and the low temperature side refrigerator. The inlet side of the machine 2b is connected by a refrigerator connecting pipe 65. Further, the outlet side of the low temperature side refrigerator 2 b is connected to the inlet side of the heat storage tank 8 by a cold water outgoing pipe 63. The cold water pump 5 is driven by an inverter 53.
The rotation speed of the cold water pump 5 is controlled by controlling the frequency input to the inverter 53. That is, the flow rate of the chilled water in the chilled water system is controlled by controlling the frequency input to the inverter 53. In the present embodiment, the cold water pump 5 is a second pump.

The cold water system includes a high temperature side refrigerator outlet temperature sensor 34a for measuring a cold water outlet temperature (high temperature refrigerator outlet cold water temperature) in the high temperature side refrigerator 2a, and a cold water outlet temperature (low temperature refrigerator in the low temperature side refrigerator 2b). A low-temperature side refrigerator outlet temperature sensor 34b for measuring the outlet cold water temperature) and a heat storage tank temperature sensor 8a for measuring the temperature of the cold water (heat storage tank temperature) in the heat storage tank 8 are disposed. The heat storage tank temperature sensor 8a may not be provided.

The heat source system 100 includes a secondary side chilled water system including the heat storage tank 8 and the load side 3.
In the secondary chilled water system, the secondary outlet side of the heat storage tank 8 and the inlet side of the load side 3 are connected by a secondary cooling forward pipe 66 having a secondary chilled water pump 5a, and the outlet side of the load side 3 and the heat storage tank 8 are connected. The secondary inlet side is connected by a secondary cooling return pipe 67. With this configuration, cold water is supplied to the load side 3 via the heat storage tank 8.
The secondary chilled water pump 5a is driven by an inverter 53a.
And the thermal storage tank secondary exit temperature sensor 81 which measures the secondary outlet temperature (cold storage tank secondary exit cold water temperature) in the thermal storage tank 8, and the secondary inlet temperature (thermal storage tank secondary entrance) of the cold water in the thermal storage tank 8 A heat storage tank secondary inlet temperature sensor 82 for measuring the cold water temperature) and a flow meter 83 for measuring the flow rate of the cold water in the secondary side cold water system.

The heat storage tank 8 is a water tank for storing cold water, for example, and is a heat storage means for storing cold heat by storing cold water cooled by the high temperature side refrigerator 2a and the low temperature side refrigerator 2b. The load side 3 is configured to be cooled by the amount of heat supplied by the heat storage tank 8, and the high temperature side refrigerator 2 a and the low temperature side refrigerator 2 b cool the cold water stored in the heat storage tank 8, thereby storing heat. Heat is stored in the tank 8.
The heat storage tank 8 has a configuration in which, for example, a secondary cooling forward pipe 66 is connected in the vicinity of the cold water outgoing pipe 63 and a cold water return pipe 64 is connected in the vicinity of the secondary cooling backward pipe 67. When the chilled water pump 5 and the secondary chilled water pump 5a are driven, the chilled water flowing through the chilled water outgoing pipe 63 and flowing into the heat storage tank 8 flows into the secondary cooling forward pipe 66, and the secondary cooling return pipe 67. It is preferable that the cold water flowing through the heat storage tank 8 flows into the cold water return pipe 64.
Further, when the chilled water pump 5 is driven and the secondary chilled water pump 5a is stopped, it is preferable that the chilled water flowing through the chilled water outgoing pipe 63 and flowing into the heat storage tank 8 is stored from the chilled water outgoing pipe 63 side. When the chilled water pump 5 is stopped and the secondary chilled water pump 5a is driven, chilled water stored in the vicinity of the chilled water outgoing pipe 63 flows into the secondary cooling outgoing pipe 66 and flows through the secondary cooling return pipe 67. A configuration in which the cold water flowing into the heat storage tank 8 is stored in the vicinity of the secondary cooling return pipe 67 is preferable.

According to this configuration, the heat storage tank 8 functions as a pipe line when the chilled water pump 5 and the secondary chilled water pump 5a are driven, and stores heat when the chilled water pump 5 is driven and the secondary chilled water pump 5a is stopped. The tank 8 functions as a buffer and stores cold water (cold heat is stored). Further, when the cold water pump 5 is stopped and the secondary cold water pump 5a is driven, the heat storage tank 8 functions as a buffer for supplying cold water to the load side 3 (supplying the amount of heat stored).
Furthermore, when the flow rate of the chilled water pump 5 is larger than the flow rate of the secondary chilled water pump 5a, the heat storage tank 8 stores heat corresponding to the difference in flow rate, and the flow rate of the chilled water pump 5 is greater than the flow rate of the secondary chilled water pump 5a. When it is small, the heat storage tank 8 supplies a heat amount corresponding to the difference in flow rate to the load side 3.

Furthermore, the heat source system 100 includes an outside air thermometer 37 that measures the outside air temperature and an outside air hygrometer 38 that measures the humidity of the outside air.

As described above, the heat source system 100 according to the present embodiment includes the cooling water system, the chilled water system, and the secondary side chilled water system, and the cooling water that circulates the cooling water system and the chilled water that circulates the chilled water system are on the high temperature side The cold water is cooled by heat exchange between the refrigerator 2a and the low-temperature refrigerator 2b.
Then, the cooled cold water is supplied to the load side 3 (room or device) via the heat storage tank 8 to cool the load side 3. The operation of the heat source system 100 for cooling the load side 3 is referred to as a cooling operation.

Further, the cold water cooled by the high temperature side refrigerator 2 a and the low temperature side refrigerator 2 b is stored in the heat storage tank 8, whereby heat is stored in the heat storage tank 8. The operation for storing heat in the heat storage tank 8 is referred to as heat storage operation.
The cooling fan 6, the high-temperature side cooling water pump 4 a, the low-temperature side cooling water pump 4 b, the cold water pump 5, and the secondary cold water pump 5 a disposed in the heat source system 100 having such a configuration are controlled by the control device 71. . Hereinafter, in this embodiment, it is set as a refrigerator including the high temperature side refrigerator 2a and the low temperature side refrigerator 2b.

Although FIG. 1 shows a configuration including two refrigerators (high temperature side refrigerator 2a, low temperature side refrigerator 2b), three or more refrigerators are arranged in series in the cold water system. It may be a configuration. Moreover, although illustration is abbreviate | omitted, the structure by which the combination of the refrigerator arrange | positioned in series is arrange | positioned in multiple rows | lines parallel may be sufficient.

The control device 71 according to this embodiment calculates the wet bulb temperature of the outside air from the outside air temperature measured by the outside air thermometer 37 and the outside air humidity measured by the outside air hygrometer 38, and further, cold water in the secondary side chilled water system The load required by the load side 3 is calculated based on the flow rate, the heat storage tank secondary inlet cold water temperature, and the heat storage tank secondary outlet cold water temperature. And the rotational speed of the secondary chilled water pump 5a is controlled by the discharge pressure constant control and the terminal pressure constant control according to the load which the load side 3 requires. That is, the flow rate of cold water in the secondary side cold water system is controlled. A known technique can be used for the discharge pressure constant control and the terminal pressure constant control. Hereinafter, the load requested by the load side 3 is referred to as a requested load.
In addition, it may replace with the external temperature thermometer 37 and the external air hygrometer 38, and the structure provided with the wet bulb thermometer which is not shown in figure may be sufficient.

The required load on the load side 3 is a load when the load side 3 is cooled by cold water, and is a value determined by the state of the load side 3, for example, the room temperature of the room or the temperature of the apparatus.
The required load on the load side 3 is calculated based on the chilled water flow rate in the secondary chilled water system, the heat storage tank secondary inlet cold water temperature, and the heat storage tank secondary outlet cold water temperature. Note that the heat storage tank secondary outlet temperature sensor 81 may not be provided, and the set value of the heat storage tank secondary outlet cold water temperature may be set as the required load on the load side 3. According to this configuration, the heat storage tank secondary outlet temperature sensor 81 is not required, and the heat source system 100 having a simpler configuration can be obtained.

Further, the control device 71 sets the high temperature side refrigerator 2a and the low temperature side so that the outlet temperature of the cold water in the high temperature side refrigerator 2a becomes a target value and the outlet temperature of the cold water in the low temperature side refrigerator 2b becomes another target value. Each refrigerator 2b is controlled. Alternatively, the refrigerator (the high temperature side refrigerator 2a, the low temperature side refrigerator 2b) has a control function for maintaining the outlet temperature of the cold water (high temperature refrigerator outlet cold water temperature, low temperature refrigerator outlet cold water temperature) constant, and a control device It is good also as a structure which refrigerator itself itself controls with an apparatus single-piece | unit so that the target value of the exit temperature of cold water notified from 71 may be maintained.
Furthermore, the control device 71 controls the rotation speed of the cooling fan 6 (the amount of air blown to the cooling tower 1) so that the cooling tower outlet cooling water temperature becomes the target value.

And the control apparatus 71 which concerns on this embodiment is the characteristic value (cooling in a component apparatus and piping) of the state of the external air which changes sequentially (especially wet bulb temperature), the required load of the load side 3, and the apparatus which comprises the heat source system 100. The water temperature and the flow rate are optimized so that the energy consumption predicted based on the resistance of the water and the cold water is minimized. And based on the calculation result of the optimization calculation, the temperature of the cooling water (cooling tower outlet cooling water temperature), the temperature of the cooling water (high temperature refrigerator outlet cooling water temperature, low temperature refrigerator outlet cooling water temperature), the cooling water flow rate (cooling water) , Or the rotational speed of the cooling water pumps 4a and 4b) and the target value of the cooling water flow (the cooling water flow ratio or the rotational speed of the cold water pump 5).
The flow rate ratio of the cooling water is a ratio with respect to the flow rate of the cooling water when the cooling water pumps 4a and 4b are rated and the flow rate ratio of the cold water is a ratio with respect to the flow rate of the cold water when the cooling water pump 5 is rated. It is.

In order to achieve such a configuration, in the present embodiment, the control device 71 sets the high-temperature side cooling water pump 4a, the low-temperature side cooling water pump 4b, the cold water pump 5, and the cooling fan 6 as control targets, and performs control operations by optimization calculation. The control target value is set and the heat source system 100 is controlled.

For example, in the case of a cooling operation in which the load side 3 is cooled with cold water, the control device 71 sets the required load on the load side 3 to a load processed by the refrigerator (hereinafter referred to as a refrigerator load).
The control device 71 uses the refrigerator load, the wet bulb temperature of the outside air, the cooling tower outlet cooling water temperature, the high temperature refrigerator outlet cooling water temperature, the low temperature refrigerator outlet cooling water temperature, the cooling water flow rate, and the cooling water flow rate as parameters. Resistance to cold water (flow path resistance) of the high temperature side refrigerator 2a, the low temperature side refrigerator 2b, and the cold water pump 5, and the high temperature side refrigerator 2a, the low temperature side refrigerator 2b, and the high temperature side cooling water Based on the resistance (flow path resistance) of the pump 4a, the low temperature side cooling water pump 4b, and the cooling tower 1 to the cooling water, the control target (high temperature side cooling water pump 4a, low temperature side cooling water pump 4b, cold water pump) 5. Simulate the total energy consumption in the cooling fan 6).

The control device 71 includes cooling water and cold water in pipes (cooling water outgoing pipe 61a, branch outgoing pipe 61b, cooling water return pipe 62a, branch return pipe 62b, cold water outgoing pipe 63, cold water return pipe 64, refrigerator connection pipe 65). The pump head of each pump (high temperature side cooling water pump 4a, low temperature side cooling water pump 4b, cold water pump 5) is calculated based on the result of predicting or actually measuring the relationship between the pressure loss and the flow rate of the water, and the relationship between the flow rate and the pump head Each pump power is calculated from And the control apparatus 71 calculates the energy consumption of each pump from each calculated pump power.

Further, the control device 71 uses the general enthalpy standard overall volume transfer coefficient and the cooling tower performance approximation formula to determine the outdoor air condition, the cooling water flow rate, the cooling water temperature (cooling tower outlet cooling water) from the performance of the cooling tower 1. The air flow ratio of the cooling fan 6 corresponding to the temperature and the cooling tower inlet cooling water temperature) is obtained, and the power consumption of the cooling tower 1 is predicted.
The air volume ratio of the cooling fan 6 is a ratio to the air volume when the cooling fan 6 is rated.
The energy consumption of the refrigerator is predicted as the energy consumption when the refrigerator is operated with a refrigerator load.
Further, the control device 71 optimizes the total energy consumption of the heat source system 100 with the evaluation function W, the number of operating refrigerators, the flow rate of chilled water and cooling water (rotational speed of each pump), and the temperature of the chilled water and cooling water. As an optimization variable, an optimization variable is searched so that the evaluation function W represented by the following equation (1) is minimized, and a control target value to be controlled is determined based on the searched optimization variable.
W = Eref1 + Eref2 + Ecp + Ecwp1 + Ecwp2 + Ect (1)
However,
Eref1: Energy consumption of the high temperature side refrigerator [kW]
Eref2: Energy consumption [kW] of the low-temperature side refrigerator
Ecp: Energy consumption of chilled water pump [kW]
Ecwp1: Energy consumption of the high-temperature side cooling water pump [kW]
Ecwp2: Energy consumption of the low-temperature side cooling water pump [kW]
Ect: Energy consumption of the cooling tower [kW]

That is, the control device 71 sets the cooling water flow rate, the cooling water flow rate, the high-temperature freezer outlet cold water temperature, the low-temperature freezer outlet cold water temperature, and the cooling tower outlet cooling so that the evaluation function W shown in Expression (1) is minimized. Set the target water temperature.

Specifically, the control device 71 includes an energy consumption amount (Eref1) of the high temperature side refrigerator 2a, an energy consumption amount (Eref2) of the low temperature side refrigerator 2b, an energy consumption amount (Ecp) of the cold water pump 5, and a high temperature side cooling water pump. The energy consumption (Ecwp1) of 4a, the energy consumption (Ecwp2) of the low temperature side cooling water pump 4b, and the energy consumption (Ect) of the cooling tower 1 are set to values that minimize the evaluation function W. The flow rate of the cooling water, the flow rate of the cold water, the cold water temperature at the high temperature refrigerator outlet, the cold water temperature at the low temperature refrigerator outlet, and the cooling water temperature at the cooling tower outlet are set as respective target values.

And the control apparatus 71 is the flow rate of cooling water (the flow rate of cooling water in the high temperature side refrigerator 2a, the flow rate of cooling water in the low temperature side refrigerator 2b), the flow rate of cold water, the high temperature refrigerator outlet cold water temperature, and the low temperature refrigerator exit. Control target values of the control target (high temperature side cooling water pump 4a, low temperature side cooling water pump 4b, cold water pump 5, cooling fan 6) so that the cold water temperature and the cooling tower outlet cooling water temperature become the set target values, respectively. Set.

Specifically, the control device 71 determines the control target value of the rotational speed of the high temperature side cooling water pump 4a so that the flow rate of the cooling water in the high temperature side refrigerator 2a becomes the set target value, and in the low temperature side refrigerator 2b. The control target value of the rotation speed of the low temperature side cooling water pump 4b is determined so that the flow rate of the cooling water becomes the set target value, and the rotation speed control of the cold water pump 5 is controlled so that the flow rate of the cooling water becomes the set target value. The target value is determined, and further, the control target value of the rotational speed of the cooling fan 6 is determined so that the cooling tower outlet cooling water temperature becomes the set target value.
The cooling tower outlet cooling water temperature is maintained at the set target value by ON / OFF of the cooling fan 6 and feedback control of the rotation speed so that the measured value of the cooling tower outlet temperature sensor 31 is constant. May be. With this configuration, for example, even when the outside air state fluctuates, the cooling tower outlet cooling water temperature can be maintained at a set target value with high accuracy.
And the control apparatus 71 controls a control object based on a control target value.
Further, the control device 71 operates the high temperature side refrigerator 2a and the low temperature side refrigerator 2b using the load demand on the load side 3 as an operation load. Specifically, the high temperature side refrigerator 2a and the low temperature side refrigerator 2b are partially loaded so that the sum of the operation load of the high temperature side refrigerator 2a and the operation load of the low temperature side refrigerator 2b becomes the required load on the load side 3. To do.
At this time, a configuration in which the value obtained by dividing the required load by the operating load per refrigerator is the number of refrigerators to be operated.
In addition, for example, the operation load may be distributed so that the loads on the high temperature side refrigerator 2a and the low temperature side refrigerator 2b are equal.

With this configuration, even when the refrigerator (high temperature side refrigerator 2a, low temperature side refrigerator 2b) cannot be operated at the maximum load, the COP (Coefficient Of Performance) of the heat source system 100 is maintained high and the refrigerator is partially Load operation can be performed and energy saving can be achieved.

Then, the control device 71 changes the setting of the control target value at a predetermined time interval (for example, every 10 minutes) so as to follow the change in the outside air state (wet bulb temperature) and the required load on the load side 3. It is preferable to be configured to do so. With this configuration, the heat source system 100 can maintain a high COP even when the wet bulb temperature of the outside air and the load on the load side 3 change.

In the optimization calculation, the load distribution of the high-temperature side refrigerator 2a and the low-temperature side refrigerator 2b to be operated is set to a fixed value. For example, the administrator of the heat source system 100 arbitrarily selects the outlet temperature of the cold water (high-temperature refrigerator outlet cold water temperature). It is good also as a structure which can set a low-temperature freezer exit cold water temperature). According to this configuration, for example, it is possible to cope with the case where the setting of the outlet temperature of the cold water of the refrigerator (high temperature side refrigerator 2a, low temperature side refrigerator 2b) cannot be changed at the time of failure or maintenance.
Further, for example, it is possible to save energy when operating one of the high temperature side refrigerator 2a or the low temperature side refrigerator 2b.

FIG. 2 (a) shows the change in COP when the control target values of the controlled objects (the high temperature side cooling water pump 4a, the low temperature side cooling water pump 4b, the cold water pump 5, and the cooling fan 6) are constant. (B) shows the change in COP when the control target value is set based on the optimization calculation.
2 (a) and 2 (b) show a load factor of 200% when both the high temperature side refrigerator 2a (see FIG. 1) and the low temperature side refrigerator 2b (see FIG. 1) are operated at a load factor of 100%. It is said.
The load factor here is the ratio of the operating load to the maximum load of the refrigerator.

∙ A turbo chiller operated at a constant rotational speed has maximum efficiency when it is near the rated load, so efficiency is improved when there is a predetermined temperature difference. The high temperature refrigerator outlet cold water temperature and the low temperature refrigerator outlet cold water temperature are set as design values of the heat source system 100 (see FIG. 1). Therefore, in the cold water system, the high-temperature side refrigerator 2a and the low-temperature side refrigerator 2b are efficiently operated when the temperature difference between the preset high-temperature refrigerator inlet temperature and the low-temperature refrigerator outlet cold water temperature at the rated load. Thus, the maximum load of each refrigerator is determined.

However, the temperature of the hot chiller inlet chilled water changes depending on the wet bulb temperature of the outside air or the load requirement on the load side 3, and the temperature difference between the hot chiller 2a (high temperature chiller inlet chilled water temperature and high temperature chiller outlet cold water). The temperature difference may be small. At this time, the high temperature side refrigerator 2a is not operated at the maximum load and the efficiency is lowered.

FIG. 2A is a diagram showing this state. When the control target value to be controlled is made constant, the COP of the heat source system 100 (see FIG. 1) decreases as the load factor of the refrigerator decreases. It shows that.

On the other hand, the control device 71 (see FIG. 1) according to the present embodiment has the energy of the heat source system 100 (see FIG. 1) when the wet bulb temperature of the outside air or the load on the load side 3 (see FIG. 1) changes. Optimization calculation is performed so that the evaluation function W indicating the total value of consumption is minimized. Then, the control target value of the control target is set based on the optimization calculation, and the control target is controlled. Further, the high temperature side refrigerator 2a and the low temperature side refrigerator 2b are operated with partial loads.
FIG. 2 (b) is a diagram showing this state, in which the wet bulb temperature of the outside air and the load on the load side 3 change, and the high temperature side refrigerator 2a and the low temperature side refrigerator 2b are operated at a partial load. Even if it exists, it shows that COP of the heat source system 100 is maintained high.

Thus, in the heat source system 100 (see FIG. 1) according to the present embodiment, the control device 71 (see FIG. 1) is optimal when the wet bulb temperature of the outside air or the load on the load side 3 (see FIG. 1) changes. The control target value of the control target is set by executing the conversion calculation, and the COP during operation is kept high.

That is, the heat source system 100 (see FIG. 1) according to the present embodiment distributes the load between the high temperature side refrigerator 2a (see FIG. 1) and the low temperature side refrigerator 2b (see FIG. 1) arranged in series in the cold water system. Can be suitably changed to maintain a high COP during operation. And energy saving can be aimed at.

Note that the control device 71 (see FIG. 1) is not configured to perform an optimization calculation according to a change in the wet bulb temperature of the outside air or a change in the required load on the load side 3 (see FIG. 1). A configuration may be adopted in which a map-format data table indicating correspondence between the temperature, the required load on the load side 3 and the control target value that minimizes the evaluation function is set in advance.
In the case of such a configuration, the control device 71 refers to the data table based on the wet bulb temperature of the outside air and the required load on the load side 3, thereby performing the control target of the control target without executing the optimization calculation. The value can be set to minimize the aforementioned evaluation function. Therefore, the calculation load of the control device 71 can be reduced.

Such a data table is obtained, for example, by appropriately inputting the wet bulb temperature of the outside air and the load on the load side 3 (see FIG. 1) into a simulator that models the heat source system 100 (see FIG. 1), and performing the above-described optimization calculation. It can be created by executing and setting the control target value of the control object corresponding to the input wet bulb temperature and load.
By storing the data table created in this manner in a storage unit (not shown) of the control device 71 (see FIG. 1), the control device 71 responds to the wet bulb temperature of the outside air and the required load on the load side 3. By referring to the data table, the control target value to be controlled can be set.

In addition, the heat source system 100 according to the present embodiment (see FIG. 1) may be configured to store heat in the heat storage tank 8 in a heat storage operation performed in a predetermined heat storage time zone based on a predetermined time schedule. it can. At the time of the heat storage operation, the control device 71 (see FIG. 1) can keep the COP of the heat source system 100 high by optimizing the load corresponding to the load factor at which the COP is high as the refrigerator load. Become.

The time schedule for the heat storage operation of the heat source system 100 (see FIG. 1) is based on, for example, a predetermined period (monthly or monthly) so that the heat storage operation is performed in a time zone in which the energy consumption can be minimized based on, for example, an annual outdoor air fluctuation pattern. Preferably, it is set every week.
Furthermore, for example, the control device 71 (see FIG. 1) has a calendar function, and by performing the heat storage operation according to the time schedule that matches the date of the heat storage operation, the energy consumption in the heat storage operation of the heat source system 100 can be suppressed. With this configuration, it is possible to save energy in the heat storage operation.
Further, the load factor during the heat storage operation is stored in a storage unit (not shown) as data predicted in advance from the past load pattern and outside air conditions in the past, and the controller 71 stores the data from the storage unit during the heat storage operation. A configuration that reads and sets the load factor is preferable. According to this configuration, the control device 71 can set the load factor by predicting the case where the heat storage amount of the heat storage tank 8 does not become the maximum in the heat storage time when the heat source system 100 is subjected to the heat storage operation at a load factor that results in a high COP. . And it can avoid that the thermal storage amount of the thermal storage tank 8 does not become the maximum by the thermal storage operation over thermal storage time.

With reference to FIG. 3, the procedure when the control device 71 (see FIG. 1) performs the heat storage operation will be described (see FIGS. 1 and 2 as appropriate).
For example, in the case of a time schedule in which the heat storage operation time is set from 8:00 pm (20 pm) to 8:00 am tomorrow morning, the control device 71 will store the amount of heat stored in the heat storage tank 8 and the humidity of the outside air at 20:00. The sphere temperature is calculated (step S100).
Specifically, the control device 71 sets the amount of heat that the heat storage amount of the heat storage tank 8 is insufficient with respect to a predetermined heat storage amount (rated heat storage amount) as the heat amount for storing heat.
For example, the controller 71 sets the amount of heat (cooling amount) to store the amount of heat necessary for the heat storage tank temperature of the heat storage tank 8 to fall to a predetermined temperature set in advance.

Further, the control device 71 sets a preset load as a refrigerator load. That is, the control device 71 sets the refrigerator load (step S101).
For example, when the load corresponding to the maximum load factor of the COP shown in FIG. 2B is set, the COP of the heat source system 100 can be maintained at the maximum during the heat storage operation.

The control device 71 uses the refrigerator load, the wet bulb temperature of the outside air, the cooling tower outlet cooling water temperature, the high temperature refrigerator outlet cooling water temperature, the low temperature refrigerator outlet cooling water temperature, the cooling water flow rate, and the cooling water flow rate as parameters, As described above, the optimization operation is executed so that the evaluation function W represented by the expression (1) is minimized (step S102).

Furthermore, the control device 71 controls the controlled object with a control target value set based on the optimization calculation (step S103).

The control device 71 can perform the heat storage operation by operating the refrigerator with the refrigerator load at the maximum COP by repeatedly executing the procedures of steps S100 to S103 at predetermined unit time (for example, 10 minutes) intervals.

Conventionally, as shown in FIG. 4 (a), the heat source system 100 has a refrigerator load in which the cooling amount is 100% from 8:00 pm (20 pm) which is a heat storage time zone to 8:00 am tomorrow morning. The refrigerator is operated and the heat storage operation is performed. 4A and 4B, the cooling amount when the load factor is 200% is 100%.
However, as shown in FIG. 2B, for example, when the COP of the heat source system 100 does not become maximum when the load factor is 200%, the operation of the refrigerator with the refrigerator load at which the load factor becomes 200%, Energy consumption can be suppressed by operating the refrigerator at a load factor (for example, 150%) at which the COP of the heat source system 100 is maximized.

In this case, as shown in FIG. 4 (b), for example, the amount of cooling per hour is 100% or less, so the time for the heat storage operation (the drive time of the refrigerator) becomes long, but the amount of energy consumption is small. Become.
That is, the total area of the bar graph shown in FIG. 4B (area of the portion shown by shading) is smaller than the total area of the bar graph shown in FIG. 4A (surface of the portion shown by shading). Become.

Thus, the heat source system 100 (see FIG. 1) according to the present embodiment has a refrigerator (high temperature side refrigerator 2a (see FIG. 1), low temperature) at a load factor that maximizes the COP of the heat source system 100 during the heat storage operation. The side refrigerator 2b (see FIG. 1) can be operated, and energy saving in the heat storage operation can be achieved.

Further, the heat source system 100 (see FIG. 1) according to the present embodiment is refrigerated with a load having a load factor corresponding to the maximum COP with respect to the required load on the load side 3 (see FIG. 1) during the cooling operation. It is also possible to perform a partial load operation of the machine and adjust the difference between the operation load of the refrigerator and the required load on the load side 3 by the amount of heat stored in the heat storage tank 8 (see FIG. 1).
For example, when the load factor of the refrigerator corresponding to the required load on the load side 3 is 200%, as shown in FIG. 2B, the load factor corresponding to the maximum COP is lower than 200% (for example, 150%), the refrigerator may be operated using a load having a load factor corresponding to the maximum COP as an operating load, and the shortage with respect to the required load may be allocated by the heat storage consumption of the heat storage tank 8.

In this case, when the heat capacity of the heat storage tank 8 (see FIG. 1) is large, fluctuations in the required load on the load side 3 (see FIG. 1) can be absorbed by the amount of heat stored in the heat storage tank 8, and the refrigerator is stored in the heat storage tank. The load for storing heat in 8 can be made constant. Therefore, the refrigerator can be operated at a load factor corresponding to the maximum COP.
On the other hand, when the heat capacity of the heat storage tank 8 is small, the required load on the load side 3 may exceed the heat storage amount of the heat storage tank 8 when the heat storage amount of the heat storage tank 8 is consumed. In this case, a configuration in which the refrigerator is operated so that the required load on the load side 3 cannot be applied by the heat storage in the heat storage tank 8 and the load factor corresponding to the required load on the load side 3 is obtained.

Referring to FIG. 5, while the control device 71 (see FIG. 1) stores heat in the heat storage tank 8 (see FIG. 1), the heat source system 100 (see FIG. 1) operates the refrigerator at a load factor at which the maximum COP is obtained. The procedure is described (refer to FIGS. 1 and 2 as appropriate).

First, the control device 71 calculates a load (required load on the load side 3) by which cold water cools the load side 3 and a wet bulb temperature of the outside air (step S1).
The required load on the load side 3 can be calculated based on the cold water flow rate, the heat storage tank secondary inlet cold water temperature, and the heat storage tank secondary outlet cold water temperature in the secondary side cold water system as described above.

Further, the control device 71 calculates the amount of heat stored in the heat storage tank 8 based on the operating load of the high temperature side refrigerator 2a and the low temperature side refrigerator 2b being driven and the load on the load side 3 (step S2). Specifically, the control device 71 calculates the amount of heat that can be stored in the heat storage tank 8 based on the difference between the operating load of the refrigerator and the load on the load side 3, and integrates the calculated amount of heat during operation of the cooling system 100. The value is the amount of heat stored in the heat storage tank 8.

When the calculated heat storage amount is lower than the lower limit value (step S3 → Yes), the control device 71 compares the required load on the load side 3 with the current operating load of the refrigerator (step S4). When the required load is smaller than the operating load (step S4 → Yes), the control device 71 sets the load preset as the load for the heat storage operation to the refrigerator load (step S5), and the required load Is greater than the operating load (step S4 → No), the required load on the load side 3 is set to the refrigerator load (step S6).
For example, as described above, the load set in advance as the load when performing the heat storage operation is preferably a load corresponding to the maximum load factor of the COP of the heat source system 100.
The lower limit value of the heat storage amount is preferably set in advance as a design value of the heat storage tank 8.

In addition, when comparing the heat storage amount of the heat storage tank 8 with a lower limit value, for example, when the heat storage tank temperature measured by the heat storage tank temperature sensor 8a is higher than a preset threshold, the control device 71 stores the heat storage of the heat storage tank 8. The structure which determines with the quantity being lower than a lower limit may be sufficient. In this case, it is preferable that the lower limit value of the heat storage amount is set as a threshold temperature.

Then, the control device 71 includes the refrigerator load, the wet bulb temperature of the outside air, the cooling tower outlet cooling water temperature or the rotation speed ratio of the cooling fan 6, the high temperature refrigerator outlet cooling water temperature, the low temperature refrigerator outlet cooling water temperature, and the high temperature side cooling water. Using the rotation speed ratio or cooling water flow rate ratio of the pump 4a and the low temperature side cooling water pump 4b and the rotation speed ratio or cooling water flow rate ratio of the cold water pump 5 as parameters, as described above, the evaluation represented by the equation (1) An optimization calculation is executed so that the function W is minimized (step S7), and a control target value to be controlled is set.
And the control apparatus 71 controls a control object based on a control target value (step S8).
The rotational speed ratio of the cooling fan 6, the rotational speed ratio of the high temperature side cooling water pump 4a and the low temperature side cooling water pump 4b, and the rotational speed ratio of the cold water pump 5 are ratios to the rated rotational speed, respectively.

On the other hand, when the calculated heat storage amount is equal to or greater than the preset lower limit value of the heat storage amount (step S3 → No), the control device 71 compares the heat storage amount with the upper limit value of the heat storage amount (step S9). ). And when the said heat storage amount is smaller than an upper limit (step S9-> Yes), the control apparatus 71 advances a procedure to step S5.
That is, the control device 71 sets the load when performing the heat storage operation to the refrigerator load.
Moreover, when the said heat storage amount is more than the upper limit of heat storage amount (step S9-> No), the control apparatus 71 determines with the heat storage tank 8 heat storage being able to cool the load side 3, and stops a refrigerator (step S10). ).
The upper limit value of the heat storage amount is preferably set in advance as a design value of the heat storage tank 8.
Similarly to the comparison with the lower limit value of the heat storage amount, when the heat storage tank temperature measured by the heat storage tank temperature sensor 8a is lower than a preset threshold value, the control device 71 determines that the heat storage amount of the heat storage tank 8 is the upper limit value. The structure which determines with it being higher may be sufficient. In this case, the upper limit value of the heat storage amount is preferably set as a threshold temperature.

Then, as described above, the control device 71 repeatedly executes the steps S1 to S10 at a predetermined time interval such as a 10-minute interval while cooling the load side 3 to thereby adjust the wet bulb temperature of the outside air. Even when the required load on the load side 3 changes, the COP of the heat source system 100 can be maintained at the maximum.

According to this configuration, when the heat storage amount (cooling amount) of the heat storage tank 8 (see FIG. 1) is greater than the lower limit value and smaller than the upper limit value, the refrigerator is partially loaded at a load factor at which the COP of the heat source system 100 is maximized. Heat can be stored in the heat storage tank 8. Further, the COP of the heat source system 100 can be maximized, and energy saving during the cooling operation can be achieved.
In addition, when the heat storage amount (cooling amount) of the heat storage tank 8 is smaller than the lower limit value, the refrigerator at a load factor that maximizes the COP of the heat source system 100 even when the required load on the load side 3 is smaller than the operating load of the refrigerator. Can be stored in the heat storage tank 8. That is, even when the required load on the load side 3 becomes small, the COP of the heat source system 100 can be maintained at the maximum.

Further, when the amount of heat stored in the heat storage tank 8 (see FIG. 1) is smaller than a predetermined lower limit value, if the required load on the load side 3 is equal to or higher than the operating load of the refrigerator, the refrigerator is replaced with the required load on the load side 3 The COP of the heat source system 100 can be kept high by performing the partial load operation and further performing the optimization calculation so that the energy consumption is minimized, and energy saving can be achieved.
Furthermore, since the refrigerator can be stopped when the amount of heat stored in the heat storage tank 8 is equal to or greater than a predetermined upper limit value, energy can be saved also in this case.
As described above, the control device 71 (see FIG. 1) can maintain the COP of the heat source system 100 (see FIG. 1) high during the cooling operation, and can perform partial load operation of the refrigerator, thereby saving energy. .
For example, even when the heat capacity of the heat storage tank 8 is small, the COP during operation can be kept high by using the heat storage tank 8 as a heat buffer. And energy saving can be aimed at.

Furthermore, even when at least one of the wet bulb temperature of the outside air, the required load on the load side 3 (see FIG. 1), and the heat storage amount of the heat storage tank 8 (see FIG. 1) change, the control device 71 (FIG. 1). (Refer to FIG. 1), an optimization calculation can be executed to set a control target value corresponding to the change, and the COP of the heat source system 100 (see FIG. 1) can be kept high.

In addition, it changes to the structure which optimizes calculation by step S7, and as above-mentioned, the control apparatus 71 (refer FIG. 1), the wet bulb temperature of external air, the required load of the load side 3 (refer FIG. 1), and a thermal storage tank It is good also as a structure which sets the control target value of a control object with reference to the data table set beforehand based on the heat storage amount of 8 (refer FIG. 1).
That is, the control device 71 may set the control target value to be controlled based on a preset data table without performing the optimization calculation in step S7.
For example, as shown in FIG. 6, the data table in this case includes a load factor of the refrigerator determined from the wet bulb temperature of the outside air, the required load on the load side 3 and the heat storage amount of the heat storage tank 8, and an evaluation function. It is preferable that the data table is a map format showing the correspondence between the minimum control target value.
FIG. 6 shows an example of a data table indicating the relationship between the wet bulb temperature of the outside air, the load factor of the refrigerator, and the rotation speed ratio of the high-temperature side cooling water pump 4a. If such a data table is set for each control target value of another control target, the control device 71 sets the control target value of the control target based on the wet bulb temperature of the outside air and the load factor of the refrigerator. Can be set.
The amount of heat stored in the heat storage tank 8 can be calculated from the load on the load side 3 and the load factor of the refrigerator (high temperature side refrigerator 2a, low temperature side refrigerator 2b).
Moreover, it is preferable that the optimization calculation of the control target value for creating a data table as shown in FIG. 6 uses the load factor of a chilled water system as a parameter, for example.

As described above, the heat source system 100 (see FIG. 1) according to the present embodiment responds to changes in the wet bulb temperature of the outside air and changes in the load on the load side 3 (see FIG. 1) during the cooling operation and the heat storage operation. Control objects (high temperature side cooling water pump 4a (see FIG. 1), low temperature side cooling water pump 4b (see FIG. 1), cold water pump 5 (see FIG. 1), cooling fan 6 (see FIG. 1) )) Control target value can be set. And COP of the heat source system 100 can be maintained high, and energy saving can be aimed at.

Note that the present embodiment can also be applied to heat source systems having different cooling water system configurations. For example, in the heat source system 100 shown in FIG. 1, the high temperature side refrigerator 2a and the low temperature side refrigerator 2b are arranged in parallel in the cooling water system, but as shown in FIG. 7, the high temperature side refrigerator in the cooling water system. It is also possible to apply this embodiment to the heat source system 101 in which 2a and the low temperature side refrigerator 2b are arranged in series.

In the heat source system 101 shown in FIG. 7, a high-temperature side cooling water pump 4a, a high-temperature side refrigerator 2a, and a low-temperature side refrigerator 2b are arranged in series on a cooling water outgoing pipe 61a connected to the outlet side of the cooling tower 1. The cooling water cooled by the cooling tower 1 is sequentially sent to the high temperature side refrigerator 2a and the low temperature side refrigerator 2b by the high temperature side cooling water pump 4a. And the exit side of the low temperature side refrigerator 2b is connected with the inlet side of the cooling tower 1 by the cooling water return pipe 62a, and the cooling water which flowed out from the low temperature side refrigerator 2b flows into the cooling tower 1. Other configurations are the same as those of the heat source system 100 shown in FIG.
In the case of this configuration, the flow rate of the cooling water in the cooling water system is determined by the rotational speed of the high temperature side cooling water pump 4a.

7 has a configuration in which one high-temperature side cooling water pump 4a is disposed in the cooling water system, and the number of pumps can be reduced as compared with the heat source system 100 shown in FIG. Therefore, it can be configured at a lower cost than the heat source system 100 shown in FIG.

Moreover, as shown in FIG. 8, it has two cooling water systems, a high temperature side cooling water system and a low temperature side cooling water system, the high temperature side cooling water system includes a high temperature side cooling tower 1a, and the low temperature side cooling water system includes The present embodiment can also be applied to the heat source system 102 including the low temperature side cooling tower 1b.
The high temperature side cooling tower 1a is provided with a cooling fan 6a driven by an inverter 51a, and the cooling water flowing into the high temperature side cooling tower 1a is cooled by outside air blown by the cooling fan 6a. The rotation speed of the cooling fan 6a is controlled by controlling the frequency input to the inverter 51a.
The low temperature side cooling tower 1b is provided with a cooling fan 6b driven by the inverter 51b, and the cooling water flowing into the low temperature side cooling tower 1b is cooled by outside air blown by the cooling fan 6b. The rotation speed of the cooling fan 6b is controlled by controlling the frequency input to the inverter 51b.
That is, by controlling the frequency input to the inverters 51a and 51b, the amount of air blown to the high temperature side cooling tower 1a and the low temperature side cooling tower 1b is controlled.

In the high temperature side cooling water system, a high temperature side cooling water pump 4a and a high temperature side refrigerator 2a are disposed in a cooling water outgoing pipe 610a connected to the outlet side of the high temperature side cooling tower 1a, and are cooled by the high temperature side cooling tower 1a. The cooled water is fed into the high temperature side refrigerator 2a by the high temperature side cooling water pump 4a. The outlet side of the high temperature side refrigerator 2a is connected to the inlet side of the high temperature side cooling tower 1a by a cooling water return pipe 620a so that the cooling water flowing out from the high temperature side refrigerator 2a flows into the high temperature side cooling tower 1a. The
In the low temperature side cooling water system, a low temperature side cooling water pump 4b and a low temperature side refrigerator 2b are arranged in a cooling water outgoing pipe 610b connected to the outlet side of the low temperature side cooling tower 1b, and are cooled by the low temperature side cooling tower 1b. The cooled water is sent to the low temperature side refrigerator 2b by the low temperature side cooling water pump 4b. The outlet side of the low temperature side refrigerator 2b is connected to the inlet side of the low temperature side cooling tower 1b by a cooling water return pipe 620b, and the cooling water flowing out from the low temperature side refrigerator 2b flows into the low temperature side cooling tower 1b. The

Similar to the heat source system 100 shown in FIG. 1, the high temperature side cooling water pump 4a is driven by the inverter 52a, and the low temperature side cooling water pump 4b is driven by the inverter 52b.
The rotation speeds of the high temperature side cooling water pump 4a and the low temperature side cooling water pump 4b are controlled by controlling the frequencies input to the inverters 52a and 52b, respectively.
That is, the flow rate of the cooling water in the high temperature side cooling water system is controlled by controlling the frequency input to the inverter 52a, and the cooling water in the low temperature side cooling water system is controlled by controlling the frequency input to the inverter 52b. The flow rate is controlled.

Moreover, the high temperature side cooling tower exit temperature sensor 31a which measures the cooling water exit temperature (high temperature side cooling tower outlet cooling water temperature) in the high temperature side cooling tower 1a of the high temperature side cooling water system is the outlet side of the high temperature side cooling tower 1a. The low temperature side cooling tower outlet temperature sensor 31b, which is disposed in the low temperature side cooling water system and measures the outlet temperature of the cooling water in the low temperature side cooling tower 1b of the low temperature side cooling water system (low temperature side cooling tower outlet cooling water temperature), It is arrange | positioned at the exit side.
Other configurations are the same as those of the heat source system 100 shown in FIG.

In this configuration, the flow rate of the cooling water in the high temperature side cooling water system is determined by the rotation speed of the high temperature side cooling water pump 4a, and the flow rate of the cooling water in the low temperature side cooling water system is determined by the rotation speed of the low temperature side cooling water pump 4b. It is determined.
In addition, the control device 71 includes a refrigerator load, an outside air wet bulb temperature, a high temperature side cooling tower outlet cooling water temperature, a low temperature side cooling tower outlet cooling water temperature, a high temperature refrigerator outlet cooling water temperature or an air volume ratio of the cooling fan 6a, a low temperature Refrigerating machine outlet cold water temperature or air flow ratio of cooling fan 6b, high speed side cooling water pump 4a and low temperature side cooling water pump 4b rotational speed ratio or cooling water flow ratio, and cooling water pump 5 rotational speed ratio or cold water flow ratio As described above, the optimization operation is executed so that the evaluation function W represented by the expression (1) is minimized.

Thus, the present embodiment can also be applied to the heat source system 102 including two cooling towers (the high temperature side cooling tower 1a and the low temperature side cooling tower 1b). That is, this embodiment can be applied without limiting the arrangement of the high temperature side refrigerator 2a and the low temperature side refrigerator 2b and the arrangement of the cooling tower in the cooling water system, and the scope of application of this embodiment can be widened. Can do.

Although not shown, the present embodiment can also be applied to a heat source system that does not include the heat storage tank 8 (see FIG. 1). In this case, the flow rate of the cold water on the load side 3 (see FIG. 1) during the cooling operation is adjusted by the cold water pump 5 (see FIG. 1).

The present invention also contemplates design changes as follows.
For example, in the optimization calculation, the flow rate and temperature of the cooling water may be fixed values (fixed values). In this case, since the control of the rotational speed of the high temperature side cooling water pump 4a (see FIG. 1) and the low temperature side cooling water pump 4b (see FIG. 1) can be simplified, for example, the inverter 52a ( The performance required for the inverter 52b (see FIG. 1) provided in the low temperature side cooling water pump 4b may be low, and the cost can be reduced.

The refrigerator (high temperature side refrigerator 2a (see FIG. 1), low temperature side refrigerator 2b (see FIG. 1)) may be an air-cooled heat pump refrigerator. In this case, the rotational speed of the cold water pump 5 (see FIG. 1) and the target value of the outlet temperature of the cold water in the refrigerator can be optimized, and the COP characteristic of the high temperature side refrigerator 2a can be used to save energy. In addition, the refrigerator may be an inverter refrigerator that performs inverter control on the rotation speed of the compressor. By using an inverter refrigerator, the efficiency during partial load operation can be improved. The combination of the refrigerators (the combination of the high temperature side refrigerator 2a and the low temperature side refrigerator 2b) may be a combination of an absorption refrigerator and a compression refrigerator.
Also, using cold water as hot water and a refrigerator as a heat source for heating (for example, cold / hot water generator, heat pump), the optimization calculation is executed with the load during heating operation, and the result of this optimization calculation is controlled as the control target value It may be configured to. According to this configuration, energy saving during heating operation can be achieved.
The cooling tower 1 (see FIG. 1) may be an open cooling tower or a closed cooling tower, and the type of the cooling tower 1 is not limited.

In addition, when performing a heat storage operation based on a time schedule, the refrigerator load when the refrigerator is partially loaded is set based on the predicted value of the next day load and the predicted value of the wet bulb temperature of the outside air Is also possible.

As described above, the present invention can be variously changed in design and can be applied to a wider range.

1 Cooling tower 2a High temperature side refrigerator (refrigerator)
2b Low temperature side refrigerator (refrigerator)
3 Load side 4a High temperature side cooling water pump (first pump, control target)
4b Low-temperature side cooling water pump (first pump, control target)
5 Chilled water pump (second pump, control target)
6 Cooling fan (control target)
8 heat storage tank (heat storage means)
71 control device 100 heat source system

Claims (9)

1. A first cold water system in which the first cold water cooled in the cooling tower circulates;
   A second cold water system in which a second cold water for cooling the load side circulates;
   A plurality of refrigerators arranged in series in the second cold water system and moving the heat of the second cold water that has cooled the load side to the first cold water to cool the second cold water;
   A control device that controls at least a cooling fan that blows outside air to the cooling tower, a first pump that circulates the first cold water, and a second pump that circulates the second cold water, as control targets,
   To the load side is a heat source system in which the second cold water is supplied via a heat storage means for storing the second cold water cooled by the refrigerator,
   The controller is
   The control target value of the control target is set so as to minimize the evaluation function indicating the energy consumption in response to at least one change among the state of the outside air, the heat storage amount of the heat storage means, and the required load on the load side. A heat source system characterized by setting.
2. The controller is
   2. The heat source system according to claim 1, wherein the control target value is set as a load to be processed by the refrigerator in the cooling operation for cooling the load side.
3. The controller is
   The control target value is set as a load to be processed by the refrigerator during a heat storage operation in which the second cold water is cooled and stored in the heat storage means. The heat source system according to item 1.
4. The controller is
   The control target value is set as a load to be processed by the refrigerator during a heat storage operation in which the second cold water is cooled and stored in the heat storage means. The heat source system according to Item 2.
5. The controller is
   During the cooling operation for cooling the load side,
   If the required load is equal to or higher than the operating load of the refrigerator when the heat storage amount is smaller than a predetermined lower limit value, the control target value is set as a load that the refrigerator processes.
   If the required load is smaller than the operating load of the refrigerator when the heat storage amount is smaller than the lower limit value, or if the heat storage amount is greater than or equal to the lower limit value and smaller than a predetermined upper limit value, it is set in advance. The heat source system according to claim 1, wherein the control target value is set as a load that is processed by the refrigerator.
6. The data according to claim 1, further comprising data indicating correspondence between the control target value that minimizes the evaluation function, the outside air state, and the operating load of the refrigerator. 6. The heat source system according to any one of items 5.
7. The controller is
   The heat source according to claim 6, wherein the control target value is set based on the data corresponding to a change in at least one of an outside air state, the heat storage amount, and the required load. system.
8. A first cold water system in which the first cold water cooled in the cooling tower circulates;
   A second cold water system in which a second cold water for cooling the load side circulates;
   A plurality of refrigerators arranged in series in the second cold water system and moving the heat of the second cold water that has cooled the load side to the first cold water to cool the second cold water;
   A control device that controls at least a cooling fan that blows outside air to the cooling tower, a first pump that circulates the first cold water, and a second pump that circulates the second cold water, as control targets,
   To the load side is a control method of a heat source system in which the second cold water is supplied via a heat storage means for storing the second cold water cooled by the refrigerator,
   The control target value of the control target is set so as to minimize the evaluation function indicating the energy consumption in response to at least one change among the state of the outside air, the heat storage amount of the heat storage means, and the required load on the load side. Steps to set,
   And a step of controlling the controlled object based on the control target value.
9. The step of setting the control target value based on data indicating correspondence between the control target value that minimizes the evaluation function, the outside air state, and the operating load of the refrigerator. The method for controlling a heat source system according to claim 8.

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