JP6750980B2 - Air conditioning system control device, control method, control program, and air conditioning system - Google Patents

Description

The present invention relates to an air conditioning system control device, a control method, a control program, and an air conditioning system.

In recent years, computers have been used to control air conditioning systems (see, for example, Patent Documents 1 to 5 and Non-Patent Document 1).

JP, 2005-257221, A JP, 2005-197236, A JP, 2008-134013, A JP, 2006-275397, A

Kurata Masanori, "Facility Operation System Utilizing Artificial Intelligence (AI)/Wireless Sensor", Building Equipment and Plumbing, Nippon Kogyo Publishing, May 5, 2016, Vol. 54, No. 6 (Vol. 726), p.35-39

In an air conditioning system having a heat source device such as a refrigerator, in order to maximize the COP (Coefficient Of Performance) of the entire system, it is necessary to understand the characteristics of the heat source device and the cold heat production capacity, and then determine the outside air condition and heat load It is necessary to control the operation of each device according to the requirements. However, in an air conditioning system that has various equipment such as refrigerators, cooling towers, and pumps, various control parameters such as the temperature and flow rate of cooling water, the air volume of the cooling tower fan, and the operating status of each equipment are complicatedly combined, resulting in enormous volume. It is not easy to continue to specify the operating condition that maximizes the COP of the entire system from among such calculation results while following the outside air condition and the heat load that change from moment to moment.

Furthermore, air conditioning systems include not only new air conditioning systems installed in newly constructed buildings, but also existing air conditioning systems installed in existing buildings. However, in the case of an existing air conditioning system, it may be difficult to install the electronic control instrumentation that is easy to install in the new air conditioning system. It may not be possible to obtain the information necessary to identify

Therefore, the present application discloses an air conditioning control technique capable of maximizing the COP of the entire air conditioning system based on a limited small amount of information, such as information from the instrumentation normally provided in the existing air conditioning system. To do.

In order to solve the above problems, the present invention estimates the cold water temperature based on the information of the outside air and heat load, and based on the information of each device of the air-conditioning system, the estimated cooling water temperature that can manufacture the cooling water temperature I decided to estimate.

Specifically, in a controller of an air conditioning system having a heat source device and a cooling tower, based on at least information of outside air and heat load, the air conditioner estimates a chilled water temperature capable of satisfying indoor conditions by control, Based on the information of each device in the air conditioning system, the cooling water temperature that reduces the energy consumption of the entire air conditioning system is estimated, the estimated cooling water temperature is set as the control target value of the heat source unit, and the estimated cooling water temperature is cooled. Set to the control target value of the tower.

In the control device described above, the rational chilled water temperature estimated based on the information on the outside air that exerts an external influence on the room to be air-conditioned and the information on the heat load indicating the thermal state of the room is the ratio of the heat source device. Since the control target value is set, the energy consumed by the heat source device can be suppressed as compared with the case where the heat source device is continuously operated at a constant cold water temperature regardless of changes in the outside air or the like. Since the control target value of the cooling water temperature is also set to a reasonable value, the energy consumption of the cooling tower can be suppressed as compared with the case where the cooling tower fan is continuously operated at the rated value, for example. As a result, the energy consumption of the entire air conditioning system is suppressed.

Further, in the above control device, since each value is estimated based on the information of each device of the air conditioning system prepared in advance, the air conditioning system required when there is no information of each device prepared in advance It is not necessary to acquire a huge amount of process values for each part, and it is possible to suppress the energy consumption of the entire air conditioning system even with information from instrumentation that is usually provided in existing air conditioning systems.

In the estimation of the cold water temperature, a high value may be adopted within a range in which the air conditioner can satisfy indoor conditions by control. Since the heat source device consumes less energy as the temperature of cold water to be manufactured is higher, the energy consumption of the entire air conditioning system is suppressed if such cold water temperature is adopted as the control target value.

In the estimation of the cooling water temperature, the energy consumption of the entire air conditioning system is calculated for each of several cooling water temperatures that are assumed to be within the range in which the heat source machine can produce cold water of the estimated cooling water temperature, and the calculated energy is calculated. A cooling water temperature that consumes less water may be adopted. If the estimation of the cooling water temperature is performed in this way, the calculation amount required for the estimation is reduced as compared with the case where the calculation processing is performed regardless of whether the cooling water temperature is within the range of the cooling water that can be cooled by the cooling tower. be able to.

Further, the information on the heat load may be information on the operating state acquired from the heat source device. The heat processed by the air conditioning is basically transferred to the cooling tower via the heat source unit. Therefore, if the information on the heat load processed by the air conditioning system is acquired from the heat source device, it is easy to acquire the information.

The present invention can also be viewed from the aspect of the method. For example, the present invention is a method for controlling an air conditioning system having a heat source device and a cooling tower, and estimates a chilled water temperature at which the air conditioner can control indoor conditions based on at least information on outside air and heat load. Then, based on the information of each device of the air conditioning system, the cooling water temperature that reduces the energy consumption of the entire air conditioning system is estimated, the estimated cooling water temperature is set as the control target value of the heat source unit, and the estimated cooling water temperature is set. May be set to the control target value of the cooling tower.

Further, the present invention can be grasped from the aspect of a program executable by a computer. For example, the present invention is a control program for an air conditioning system having a heat source device and a cooling tower, wherein the air conditioner satisfies indoor conditions by controlling the air conditioning system control device based on at least information on outside air and heat load. Process of estimating the chilled water temperature that can be performed, and the process of estimating the cooling water temperature that reduces the energy consumption of the entire air conditioning system based on the information of each device in the air conditioning system, and the estimated chilled water temperature for controlling the heat source unit. The process of setting the target value and the process of setting the estimated cooling water temperature as the control target value of the cooling tower may be executed.

The present invention can also be understood from the aspect of the system. For example, the present invention includes a heat source device, a cooling tower, and a control device, and the control device is based on at least information on the outside air and the heat load, and the chilled water with which the air conditioner can satisfy indoor conditions by control. The temperature is estimated, the cooling water temperature that reduces the energy consumption of the entire air conditioning system is estimated based on the information of each device of the air conditioning system, and the estimated cooling water temperature is set as the control target value of the heat source unit and estimated. It may be an air conditioning system that sets the cooling water temperature to the control target value of the cooling tower.

The above-mentioned control device, control method, control program, and air conditioning system for an air conditioning system are based on a limited and limited amount of information, such as information from instrumentation that is usually provided in existing air conditioning systems. It is possible to maximize the overall COP.

FIG. 1 is a diagram showing an example of an air conditioning system. FIG. 2 is a diagram illustrating an outline of control performed by the central controller. FIG. 3 is a flowchart of control performed by the central controller. FIG. 4 is a first diagram illustrating an inference flow of the refrigerator chilled water outlet temperature by the central controller. FIG. 5 is a diagram showing an example of an air diagram. FIG. 6 is an example of a table for determining the refrigerator cold water outlet temperature based on the calculated change amount of the refrigerator cold water outlet temperature. FIG. 7: is a 2nd figure which illustrates the inference flow of the refrigerator chilled water outlet temperature by a central controller. FIG. 8: is a figure which illustrates the item used for inference of a cooling tower and cooling water temperature. FIG. 9 is a graph illustrating the range of the cooling water outlet temperature based on the outside air wet bulb temperature and the approach temperature. FIG. 10 is a flowchart illustrating the flow of the cooling water temperature inference process. FIG. 11 is a diagram for explaining calculation of power consumption of the refrigerator for each operating condition. FIG. 12 is a diagram for explaining calculation of power consumption of the auxiliary machine for each load factor of the refrigerator. FIG. 13 is a diagram for explaining the complementation of the performance characteristic data. FIG. 14: is a figure which illustrates the operation priority of a refrigerator. FIG. 15 is a diagram illustrating an operation design sheet. FIG. 16 is a graph illustrating an increase in the number of operating heat sources. FIG. 17 is a graph showing an example of the correlation between the load factor of the entire heat source and the COP of the entire system. FIG. 18 is a flowchart illustrating a process of creating an operation design sheet.

Hereinafter, embodiments of the present invention will be described. The embodiment described below is an example of the embodiment of the present invention, and the technical scope of the present invention is not limited to the following modes.

FIG. 1 is a diagram showing an example of an air conditioning system. As shown in FIG. 1, the air conditioning system 1 includes an air conditioner 10 through which air in a room 4 passes, a refrigerator 20 that cools chilled water sent to the air conditioner 10 (which is an example of a “heat source device” in the present application), and an air conditioner. A cooling tower 30 is provided for cooling the cooling water for cooling 10 by the principle of heat of vaporization. The air conditioner 10 has a coil 11 through which cold water passes inside and an electric fan 12 controlled by an inverter, and sends temperature-controlled air to the room 4 when passing through the coil 11. The cold water that passes through the coil 11 of the air conditioner 10 is carried by the cold water circulation system 40 that forms a cold water circulation path between the air conditioner 10 and the refrigerator 20. The cooling water that cools the refrigerator 20 is carried by a cooling water circulation system 50 that forms a cooling water circulation path between the cooling tower 30 and the refrigerator 20. In FIG. 1, one air conditioner 10 and two cooling towers 30 and refrigerators 20 are shown, but the number of air conditioners 10, cooling towers 30, and refrigerators 20 is the number of indoors 4. And the size, the amount of heat generated in the room 4, the climate of the area where the air conditioning system 1 is installed, and various other design factors.

The air conditioner 10 is provided with an air conditioner controller 14. The air conditioner controller 14 includes control information sent from the host device via the network 2, a set temperature input through an operation panel in the room 4, a temperature sensor and a humidity sensor installed in a return air (RA) path from the room 4. Information of the temperature sensor and the humidity sensor installed in the room 4 are input. The air conditioner controller 14 adjusts the opening degree of the air conditioner cold water flow rate adjusting valve 13 that adjusts the flow rate of the cold water passing through the coil 11 and the rotation speed of the electric fan 12 based on these pieces of information. The air conditioner controller 14 has not only a function of outputting control signals for the air conditioner chilled water flow rate adjusting valve 13 and the electric fan 12, but also various information such as a measured value of the temperature sensor and an operating state of the electric fan 12, for example. It also has the function of transmitting to the device.

The cold water circulation system 40 includes a cold water primary pump 41 installed on the inlet side of the refrigerator 20 and a cold water secondary pump 42 installed on the inlet side of the header for branching the cold water to each air conditioner 10. The cold water is forcibly circulated by the cold water primary pump 41 and the cold water secondary pump 42. The cold water primary pump 41 is a turbo pump installed for the purpose of ensuring the flow velocity of cold water passing through the tube side of the evaporator of the refrigerator 20, and is driven by an inverter-controlled motor whose rotation speed can be changed. One cold water primary pump 41 is prepared for one refrigerator 20. Therefore, the cold water circulation system 40 is provided with the same number of cold water primary pumps 41 as the refrigerators 20. The cold water secondary pump 42 is a turbo pump installed for the purpose of ensuring the flow velocity of the cold water passing through the pipe of the coil 11 of the air conditioner 10. Like the cold water primary pump 41, the cold water secondary pump 42 is of an inverter control capable of changing the rotation speed. It is driven by a motor. The number of cold water secondary pumps 42 provided in the cold water circulation system 40 is determined according to the capacity of the pump alone, the number and size of the air conditioners 10, and the like.

The cold water secondary pump 42 is provided with a secondary pump controller 44. The secondary pump controller 44 receives the control information sent from the host device via the network 2 and the information of the flow rate sensor and the temperature sensor provided in each part of the cold water circulation system 40. Based on these pieces of information, the secondary pump controller 44 determines the operating number and rotation speed of the cold water secondary pump 42, and the opening degree of the minimum flow valve 43 in the path connecting the outlet side of the cold water secondary pump 42 to the inlet side. adjust. In addition, the secondary pump controller 44 also has a function of transmitting various information such as the measured value of the flow rate sensor and the operating state of the cold water secondary pump 42 to the host device.

The cooling water circulation system 50 includes a cooling water circulation pump 51 installed on the inlet side of the refrigerator 20, and the cooling water circulation pump 51 forcedly circulates the cooling water. The cooling water circulation pump 51 is a turbo pump installed for the purpose of ensuring the flow velocity of the cooling water passing through the tube side of the condenser of the refrigerator 20, and is driven by an inverter-controlled motor whose rotation speed can be changed. One cooling water circulation pump 51 is prepared for one refrigerator 20. Therefore, the cooling water circulation system 50 is provided with the same number of cooling water circulation pumps 51 as the refrigerators 20. Since a ball tap type makeup water valve for maintaining the water level of the cooling water is provided inside the cooling tower 30, the suction pressure of the cooling water circulation pump 51 is kept substantially constant.

The refrigerator 20 is provided with a heat source controller 21. The heat source controller 21 includes control information sent from the host device via the network 2, information on a flow rate sensor for measuring the flow rate of cooling water or cold water passing through the refrigerator 20, and temperature for measuring the temperature of cooling water or cold water passing through the refrigerator 20. Sensor information is input. The heat source controller 21 adjusts the rotation speed of the cooling water circulation pump 51, the rotation speed of the chilled water primary pump 41, the rotation speed of the compressor and the vane opening degree that influence the capacity of the refrigerator 20, based on these pieces of information. .. Further, the heat source controller 21 sends various information such as the measured value of the temperature sensor and the measured value of the flow rate sensor, the operating state of the cooling water circulation pump 51, the operating state of the chilled water primary pump 41, the operating state of the refrigerator 20 to the host device. It also has the function of sending.

The cooling tower 30 is provided with a cooling tower controller 32. The cooling tower controller 32 includes control information sent from the host device via the network 2, information about a temperature sensor for measuring the temperature of the outside air, information about a humidity sensor for measuring the humidity of the outside air, and the temperature of the cooling water at the outlet side of the cooling tower 30. The information of the temperature sensor for measuring is input. The cooling tower controller 32 adjusts the rotation speed of the motor that drives the cooling tower fan 31 provided in the cooling tower 30 based on these pieces of information. The cooling tower controller 32 also has a function of transmitting various kinds of information such as measured values of the temperature sensor and the humidity sensor and the operating state of the cooling tower fan 31 to the host device.

In the air conditioning system 1 configured as described above, the following control is basically performed during the cooling operation. That is, the air conditioner controller 14 increases the opening degree of the air conditioner cold water flow rate adjusting valve 13 if the temperature of the room 4 is higher than the set temperature, and increases the opening degree of the air conditioner cold water flow rate adjusting valve 13 if the temperature of the room 4 is lower than the set temperature. Reduce the opening. In addition, the heat source controller 21 determines that the temperature of the cold water on the outlet side of the refrigerator 20 (hereinafter, referred to as “refrigerator cold water outlet temperature” or simply “chilled water temperature”) has a predetermined control target value (for example, 7). The capacity of the refrigerator 20 is adjusted so as to be maintained at (° C.). Further, the cooling tower controller 32 determines that the temperature of the cooling water on the outlet side of the cooling tower 30 (hereinafter, referred to as “cooling tower cooling water outlet temperature”, and may be simply referred to as “cooling water temperature”) is equal to that of the refrigerator 20. The cooling tower fan 31 is rotated so as to fall below a predetermined set temperature at which the condenser can exert its condensing capacity. Since each controller basically performs such control, even if the amount of heat transported by cold water or cooling water changes due to a sudden change in the thermal environment of the room 4, etc. 10, the refrigerator cold water outlet temperature is kept substantially constant by the refrigerator 20, and the refrigerator cooling water outlet temperature is kept in a range that does not hinder the operation of the refrigerator 20 to stabilize the entire system. Driving is maintained.

The basic control contents of the air conditioning system 1 are as described above. However, in the air conditioning system 1 of the present embodiment, GDoc which is a host device for maximizing the COP of the entire system (GDoc is Takasago Thermal Engineering Co., Ltd. Since it is a registered trademark of the company, it is provided with a "central controller" 3 for the sake of convenience. The central controller 3 takes in the minimum required parameters for controlling a general refrigerator, cooling tower, or air conditioner as input points, and based on the minimum required information, the COP of the entire system is maximized. The control target value of each device is calculated, and the calculated control target value is set in the controller of each device. Therefore, the central controller 3 can be attached not only to newly installed air conditioners installed in a newly constructed building but also to existing air conditioners. Here, the power consumption considered in the calculation of the COP of the entire air conditioning system is the power of the cooling water circulation pump 51, the power of the cooling tower fan 31, the power consumption of the refrigerator 20, and the power of the cold water primary pump 41. Maximizing the COP of the entire system is equivalent to minimizing the total value of these power and power consumption. It goes without saying that the power of the cold water secondary pump 42 may be included.

FIG. 2 is a diagram illustrating an outline of control performed by the central controller 3. The central controller 3 is a computer having a CPU (Central Processing Unit), a memory, an input/output interface, etc., and controls the entire air conditioning system 1 by executing a computer program. That is, when the computer program is executed, the central controller 3 executes, for example, real-time (every 10 minutes) outside air conditions (outside air temperature and humidity), indoor conditions (indoor temperature and humidity), and heat source load conditions (manufacture of refrigerators). Values such as the amount of heat) are acquired from the controller of each device, and the operating status of each air conditioning device such as the refrigerator 20, auxiliary devices (cooling water pump, chilled water pump, etc.), and air conditioner 10 that are created in advance and the device is unique. The characteristic data showing the correlation with the COP is read out and the control target value optimization processing of each device is executed according to a predetermined rule engine. Then, the central controller 3 outputs the control target value of each device optimized so that the COP of the entire air conditioning system 1 is maximized to the controller of each device. The controller of each device adjusts the control amount so that the parameter to be controlled becomes a new control target value that has been subjected to the optimization processing. The controller of each device adjusts the control amount toward the control target value subjected to the optimization processing, and as a result, the COP of the entire air conditioning system 1 becomes maximum.

FIG. 3 is a flowchart of control performed by the central controller 3. When the central controller 3 executes the computer program, the central controller 3 reads a setting file (information such as the type and number of devices included in the air conditioning system 1) stored in a recording medium such as a hard disk (S101). Next, the central controller 3 obtains the values of the outside air condition measured by the cooling tower controller 32, the indoor condition measured by the air conditioner controller 14, the heat source load condition used by the heat source controller 21, and the like from each controller. (S102). Next, the central controller 3 infers the refrigerator cold water outlet temperature (heat source cold water temperature) (S103). The central controller 3 also infers the cooling tower cooling water outlet temperature (cooling water temperature) (S104). The central controller 3 also infers the number of operating refrigerators 20 (the number of operating heat sources) (S105). Further, the central controller 3 outputs the refrigerator chilled water outlet temperature inferred in the process of step S103 and the operating number of the refrigerator 20 inferred in the process of step S105 to the heat source controller 21, and the cooling tower inferred in the process of step S104. The cooling water outlet temperature is output to the cooling tower controller 32 (S106). Next, the central controller 3 determines whether or not the air conditioning system 1 is stopped. When the positive determination is made, the control of the air conditioning system 1 is stopped, and when the negative determination is made, the step is performed. The processing after S102 is executed again (S107).

The details of each inference process will be described below.

<Step S103>
In step S103, the central controller 3 infers the refrigerator cold water outlet temperature as described above. In this inference, when the indoor condition cannot be acquired, the central controller 3 infers the refrigerator cold water outlet temperature based on the virtual indoor design condition and the virtual air conditioner design. Further, when the information on the room temperature and the relative humidity can be obtained, the central controller 3 infers the refrigerator chilled water outlet temperature based on the change state of the room temperature and the relative humidity. In the inference in step S103, the central controller 3 determines whether or not dehumidification of outside air is necessary. When the dehumidification of the outside air is not necessary and when it is determined that the air conditioning load is small, the air conditioner 10 can ignore the latent heat load in the room, so that it is sufficient to process the sensible heat load in the room. Therefore, the central controller 3 determines the operating conditions of the air conditioner 10 capable of processing the sensible heat load in the room, thereby optimizing the refrigerator cold water outlet temperature. By optimizing the chiller chilled water outlet temperature, the operating efficiency of the chiller 20 is increased, and the improvement of the COP of the entire air conditioning system 1 can be expected. The central controller 3 performs the inference process of step S103 in real time (for example, every 10 minutes). When estimating the cooling water temperature in step S104, the central controller 3 selects the cooling water temperature having the smallest total power consumption based on the estimated cooling water temperature.

(When indoor conditions cannot be acquired)
FIG. 4 is a first diagram illustrating an inference flow of the refrigerator cold water outlet temperature by the central controller 3. FIG. 4 illustrates a processing flow of inferring the refrigerator cold water outlet temperature by the central controller 3 when the indoor condition cannot be acquired. FIG. 4 is a diagram showing an example of details of the process of step S103 of FIG. Hereinafter, with reference to FIG. 4, a processing flow of inferring the refrigerator chilled water outlet temperature by the central controller 3 when the indoor condition cannot be acquired will be described.

In step S201, the central controller 3 determines whether dehumidification of the outside air is necessary. In the determination of step S201, the central controller 3 refers to the heat source load condition acquired from the heat source controller 21 and the outside air condition acquired from the cooling tower controller 32. The central controller 3 further refers to the virtual air conditioner design information determined based on the heat source design. The central controller 3 controls the room temperature and relative humidity set as control target values based on the heat source load condition, the outside air condition, and the capacity of the virtual air conditioner. The room temperature and relative humidity set as control target values are referred to as virtual room design conditions in this specification.

(Determination of virtual air conditioner design information)
The central controller 3 uses the coil inlet water temperature t _w1 , the coil outlet water temperature t _w2 , the coil water flow amount L, the coil water flow heat amount q _w , the coil inlet air temperature t _a1 , the coil outlet air temperature t _a2 as the design information of the virtual air conditioner. And the supply air volume G is determined as follows. The central controller 3 reads the setting file and sets the coil inlet water temperature t _w1 , coil outlet water temperature t _w2 of the coil 11 of the air conditioner 10 registered by the initial setting, the number of refrigerators 20 and the rated flow rate of the cold water secondary pump 42. get. Here, for example, the coil inlet water temperature t _w1 is 7° C., the coil outlet water temperature t _{w2 is} 12° C., the number of the refrigerators 20 is 3, and the rated flow rate of the cold water secondary pump 42 is 4,030 L/min. And Further, it is assumed that the air conditioning system 1 includes 100 virtual air conditioners.

The coil water flow rate L, which is the water flow rate of the cold water flowing through the coil 11 per minute, is calculated by the following mathematical expression, for example.

Based on the rated flow rate (4030 L/min) of the cold water secondary pump 42, the number of refrigerators 20 (3 units), and the number of virtual air conditioners (100 units) registered in the setting file at the time of initial setting, the coil 11 flow rate is determined. The water amount L is calculated as 121 L/min. Further, the amount of heat passing through the coil, q _w , which is the amount of heat of the cold water flowing through the coil 11, is calculated by the following mathematical expression, for example.

According to Equation 2, the coil water flow heat amount q _w is calculated as 42.21 kW based on the coil outlet water temperature t _w2 , the coil inlet water temperature t _w1 , and the coil water flow amount L. The central controller 3 acquires from the air conditioner controller 14 the coil inlet air temperature t _a1 which is the temperature of the air flowing into the coil 11 and the coil outlet air temperature t _a2 which is the temperature of the air flowing out of the coil 11. However,
When air is not flowing through the coil 11 as in the case where the air conditioning system 1 is to be operated, the initial setting values registered in the setting file are adopted as the coil inlet air temperature t _a1 and the coil outlet air temperature t _a2. To be done. Here, for example, the coil inlet air temperature t _a1 is set to 2
It is assumed that the registered temperature is 6° C. and the coil outlet air temperature ta ₂ is 17.5° C. further,
Assume that the relative humidity of the air flowing into the coil 11 is 50% RH.

FIG. 5 is a diagram showing an example of an air diagram. The psychrometric chart is filled with state values indicating various air states including absolute humidity, relative humidity, dry-bulb temperature and wet-bulb temperature, and by selecting two state values from these, the air state is selected. It is a figure created so that the user can grasp. The data related to the psychrometric chart illustrated in FIG. 5 is held in the memory of the central controller 3, for example. Referring to the air diagram in FIG. 5, the coil inlet air temperature _ta1 is 26° C. and the relative humidity is 50%.
When the RH air is cooled to the coil outlet air temperature ta ₂ of 17.5° C., the relative humidity is 8
It turns out that it becomes 5% RH. Based on such an assumption, the supply air volume G of the virtual air conditioner is calculated by the following mathematical expression, for example.

Cp in Equation 3 is the constant pressure specific heat of dry air, and ρ is the density of dry air. According to Equation 3, the supply air volume G of the virtual air conditioner is calculated as 15,291 m ³ /h. Through the above processing, the central controller 3 can determine the design information of the virtual air conditioner.

(Virtual room design conditions)
Further, the central controller 3 determines the virtual room design condition. In the determination of the virtual room design condition, it is assumed that the indoor temperature that is the control target is the above-mentioned coil outlet air temperature _ta2 and the indoor relative humidity is 85% RH that is the relative humidity of the coil outlet air.

The central controller 3, which has completed the process of designing the virtual air conditioner and the process of assuming the virtual room design condition in the above process, performs the dehumidification determination in step S201. In this determination, the central controller 3 compares the absolute humidity of the outside air acquired from the heat source controller 21 of the cooling tower 30 with the absolute humidity of the room under the virtual room design condition. First, the central controller 3 refers to the air diagram in FIG. 5 and calculates the absolute humidity in the room from the measured indoor temperature and humidity. The central controller 3 compares the calculated absolute humidity of the indoor air with the absolute humidity of the outside air. When the absolute humidity of the indoor air is higher than the absolute humidity of the outside air, the central controller 3 determines that dehumidification is not necessary (dehumidification is unnecessary in S201), and the process proceeds to step S202. When the absolute humidity of the indoor air is equal to or higher than the absolute humidity of the outside air, the central controller 3 determines that dehumidification is necessary (dehumidification is necessary in S201), and the process proceeds to step S205.

If dehumidification of the outside air is not necessary in step S201, and if it is determined that the air conditioning load is small, the virtual air conditioner can ignore the latent heat load in the room, so it is not necessary to process the latent heat load, and the sensible heat in the room does not need to be processed. It only needs to be able to handle the load. Therefore, in step S202, the central controller 3 calculates the refrigerator cold water outlet temperature (cold water temperature in the figure) capable of processing the sensible heat load in the room. The central controller 3 assumes the following items 1 to 6 when calculating a reasonable refrigerator chilled water outlet temperature that maximizes the COP of the entire system.
1. Coil water flow heat q _w and indoor heat load throughput q _a are equal.
2. The coil water flow rate L is equal to the measured value.
3. Coil water inlet/outlet temperature difference (t _w2 −t _w1 ) is equal to the measured value.
4. The supply air volume G is reduced according to the load. The lower limit value α of the supply air volume G is 20% of the rated value. The lower limit value α of the supply air amount G can be changed by changing the value registered in the setting file.
5. When the supply air volume G reaches the lower limit and the load is small, the coil inlet water temperature _tw1 is increased.
6. The upper limit value of the coil inlet water temperature t _w1 is determined by the following Expression 4.

In formula 4, CS _Lim is the upper limit of the coil inlet temperature (°C), t'is the outside air wet bulb temperature (°C), t _ap is the cooling tower approach temperature (°C), and Δt _CDS-CS is the refrigerator cooling water inlet and cooling water. It is the temperature difference (°C) at the outlet. Δt _CDS-CS is determined based on, for example, the capacity of the refrigerator 20, and is 5° C. in this embodiment.
I am trying. In Equation 4, the cooling tower cooling water outlet temperature is calculated by the sum of the outside air wet bulb temperature (t′) and the cooling tower approach temperature (t _ap ). Since the cooling water is supplied from the cooling tower 30 to the refrigerator 20, the cooling tower cooling water outlet temperature is equal to the refrigerator cooling water inlet temperature. Therefore, the central controller 3 determines the coil inlet water temperature t _w1 based on the temperature difference (Δt _CDS-CS ) between the refrigerator cooling water inlet and the chilled water outlet in consideration of the capacity of the refrigerator 20 with respect to the refrigerator cooling water inlet temperature. Upper limit CS _Lim
Can be determined. As the lower limit value of the coil inlet water temperature t _w1 , for example, a value registered in the setting file at the time of initial setting can be adopted.

Based on the above assumptions, the refrigerator cold water outlet temperature capable of processing the sensible heat load in the room is determined by, for example, Equation 5 below.

In Equation 5, t _w1new is the refrigerator cold water outlet temperature calculated this time (coil inlet water temperature), t _w1 is the current refrigerator cold water outlet temperature (coil inlet water temperature), t _a1 is the coil inlet air temperature, and t _a2 is the coil outlet. Air temperature. Further, Δt ₁ is a minimum air flow rate temperature change showing a temperature change of the air passing through the coil when the virtual air conditioner is operated at the minimum air flow rate α. That is, according to Equation 5, the coil inlet water temperature t _w1new calculated this time is the current coil inlet water temperature t _w1 plus the value obtained by subtracting the minimum airflow temperature change Δt ₁ from the temperature change of the air passing through the coil. Is calculated. The minimum airflow temperature change Δt ₁ is determined by, for example, Equation 6 below.

In Equation 6, qw is the amount of heat flowing through the coil, α is the minimum supply air volume of the virtual air conditioner, G is the supply air volume of the virtual air conditioner, ρ is the density of dry air, and Cp is the constant pressure specific heat of dry air.

In step S203, the central controller 3 determines whether to change the refrigerator cold water outlet temperature. In the determination of step S203, the central controller 3 determines the chiller chilled water based on the amount of change between the chiller chilled water outlet temperature calculated in the process of step S202 and the chiller chilled water outlet temperature calculated last time (for example, 10 minutes ago). Determine whether to change the outlet temperature. That is, when the calculated chilled water temperature tends to rise, the central controller 3 changes the setting value of the memory of the chiller chilled water outlet temperature output to the heat source controller 21 in step S106 so that the chilled water temperature rises. If the calculated chilled water temperature tends to decrease, the central controller 3 changes the set value of the memory of the chiller chilled water outlet temperature output to the heat source controller 21 in step S106 so that the chilled water temperature decreases. FIG. 6 is an example of a table for determining the refrigerator cold water outlet temperature based on the calculated change amount of the refrigerator cold water outlet temperature. In FIG.
The calculated amount of change in the refrigerator cold water outlet temperature, whether or not the refrigerator cold water outlet temperature can be changed, and the determined refrigerator cold water outlet temperature (cold water temperature in the figure) are associated with each other. In FIG. 6, t _w1new is the refrigerator cold water outlet temperature calculated this time. t _w1old is the refrigerator cold water outlet temperature calculated last time. For example, in FIG. 6, when the difference between t _w1new and t _w1old is less than or _equal to minus 1.0 and less than minus 0.5 occurs twice in a row (No. 4 in FIG. 6), the central controller 3 Determines the refrigerator cold water outlet temperature minus 1.0° C. from the previously calculated temperature (t _w1old ) as the refrigerator cold water outlet temperature. The table illustrated in FIG. 6 is held in the memory of the central controller 3, for example. When the refrigerator cold water outlet temperature is changed (change allowed in S203), the process proceeds to step S204. When the chiller cold water outlet temperature is not changed (change not permitted in S203), the process proceeds to step S206.

In step S204, the central controller 3 changes the value of its own memory so that the temperature determined in step S202 is output to the heat source controller 21 as a new setting value of the refrigerator chilled water outlet temperature in the process of step S106. To do.

In step S205, the central controller 3 returns the setting value of the refrigerator cold water outlet temperature to the rating (default value). That is, the central controller 3 sets the value of its own memory so that the rated set value of the refrigerator cold water outlet temperature is output to the heat source controller 21 as a new set value of the refrigerator cold water outlet temperature in the process of step S106. To change.

In step S206, the central controller 3 does not change the refrigerator cold water outlet temperature.

When the indoor condition cannot be acquired, the central controller 3 determines the design information of the virtual air conditioner, and determines the virtual indoor design condition based on the determined design information. The central controller 3 determines whether dehumidification of the outside air is necessary or not based on the virtual room design condition and the outside air condition acquired from the cooling tower controller 32. When the dehumidification of the outside air is not necessary and when it is determined that the air conditioning load is small, the latent heat load in the room can be ignored, so the central controller 3 controls the chilled water outlet temperature of the refrigerator that can process the sensible heat load in the room. Optimize. That is, the central controller 3 can set the refrigerating machine chilled water outlet temperature as high as the latent heat load is not processed. Since the refrigerator cold water outlet temperature can be set high, the operating efficiency of the refrigerator 20 can be improved. As a result, even if the central controller 3 cannot acquire the indoor condition, the improvement of the COP of the entire air conditioning system 1 can be expected.

(When indoor conditions can be acquired)
FIG. 7 is a second diagram illustrating an inference flow of the refrigerator cold water outlet temperature by the central controller 3. FIG. 7 illustrates a processing flow of inferring the refrigerator cold water outlet temperature by the central controller 3 when the indoor condition can be acquired. FIG. 7 is a diagram showing an example of details of the processing in step S103 of FIG. In the process of FIG. 7, the central controller 3 acquires information on the indoor temperature and relative humidity from the air conditioner controller 14. The central controller 3 determines whether to change the refrigerator chilled water outlet temperature according to the amount of change between the indoor temperature and the relative humidity acquired this time and the indoor temperature and the relative humidity acquired the previous time. The central controller 3 changes the setting value of the memory of the chiller chilled water outlet temperature output to the heat source controller 21 in step S106 so that the temperature of the chilled water is lowered when the acquired indoor temperature or the relative humidity tends to rise. To do. Further, when the acquired indoor temperature or relative humidity tends to decrease, the central controller 3 sets the memory set value of the refrigerator chilled water outlet temperature output to the heat source controller 21 in step S106 so that the temperature of the chilled water rises. To change. Hereinafter, with reference to FIG. 7, a processing flow of inferring the refrigerator cold water outlet temperature by the central controller 3 when the indoor condition can be acquired will be described.

In FIG. 7, n (n is an integer of 1 or more) is a number for identifying each room to be air-conditioned by the air conditioning system 1. The central controller 3 repeats the processing from step S301 to step S307 for each room. In step S301, the central controller 3 adds 1 to the value of n.

In step S302, the central controller 3 determines whether the air conditioner 10 for the n-th room is operating. When driving (YES in S302), the process proceeds to step S303. When not driving (NO in S302), the process is returned to step S301.

In step S303, the central controller 3 sets the allowable range of room temperature and relative humidity. The allowable range is determined by, for example, Expressions 7 to 14 below.

In Expressions 7 to 14, t _{RM_SP_LL} (n) is the indoor temperature allowable second lower limit value of the n-th room. t _{RM_SP} (n) is the set temperature set in the nth room. t%(n) is the allowable range of temperature applied to the nth room. t _{RM_SP_L} (n) is the indoor temperature allowable first lower limit value of the n-th room. t _α is a correction value within an allowable range related to temperature, and the initial value is 0.5 in this embodiment. t _{RM_SP_H} (n) is the indoor temperature permissible first upper limit value of the n-th room. t _{RM_SP_HH} (n) is the indoor temperature allowable second upper limit value of the n-th room. φ _{RM_SP_LL} (n) is an indoor humidity allowable second lower limit value in the n-th room. φ _{RM_SP_L} (n) is the first allowable lower limit of indoor humidity in the nth room. φ%(n) is the permissible range of relative humidity applied to the nth room. [phi][ _alpha] is a correction value in the allowable range of relative humidity, and the initial value is 0.5. φ _{RM_SP_H} (n) is the first allowable upper limit of indoor humidity in the n-th room. φ _{RM_SP_HH} (n) is the second indoor humidity allowable upper limit value in the n-th room. The lower limit value and the upper limit value are set in the first and second two stages in this way in order to suppress the transient fluctuation amount of the indoor environment due to the temperature change of the cold water, and to generate the heat quantity generated indoors. This is to prevent the indoor environment from deviating from the control range due to changes in outdoor air conditions.

In step S304, the central controller 3 _acquires the temperature t _{RM_PV} (n) and the relative humidity φ _{RM_PV} (n) of the n-th room from the air conditioner controller 14.

In step S305, the central controller 3 determines whether or not the temperature and the relative humidity of the n-th room acquired in step S304 are within the allowable range for the set temperature. An indoor air conditioning state determination table used for this determination is illustrated in step S305 of FIG. In the indoor air conditioning state determination table, a matrix is formed in which the horizontal axis represents the allowable temperature value and the vertical axis represents the relative humidity value determined in step S303. The central controller 3 can determine whether to change the refrigerator chilled water outlet temperature based on the indoor temperature and relative humidity and the allowable range determined in S303 by referring to the indoor air conditioning state determination table. In the indoor air conditioning state determination table, “1↓” is described in the area of t _{RM_PV} (n)>t _{RM_SP_HH} (n) and the area of φ _{RM_PV} (n)>φ _{RM_SP_HH} (n). _{Area of} t _{RM_PV} (n)<t _{RM_SP_L} (n) and φ _{RM_PV} (n)<φ _{RM_SP_LL} (n), t _{RM_PV} (n)<t _{RM_SP_LL} (n) and φ _{RM_PV} (n)<φ _{RM_SP_L} (n) In the area, “1↑” is described. _{Area of} t _{RM_SP_H} (n)<t _{RM_PV} (n)<t _{RM_SP_HH} (n) and φ _{RM_PV} (n)<φ _{RM_SP_H} (n), t _{RM_PV} (n)<t _{RM_SP_HH} (n) and φ _{RM_SP_H} (n)< In the area of φ _{RM_PV} (n)<φ _{RM_SP_HH} (n), “2↓” is written. _{Area of} t _{RM_SP_L} (n)<t _{RM_PV} (n)<t _{RM_SP_H} (n) and φ _{RM_PV} (n)<φ _{RM_SP_L} (n), t _{RM_SP_LL} (n)<t _{RM_PV} (n)<t _{RM_SP_L} (n) and _{Area of} φ _{RM_SP_LL} (n)<φ _{RM_PV} (n)<φ _{RM_SP_H} (n), t _{RM_PV} (n)<t _{RM_SP_L} (n) and φ _{RM_SP_L} (n)<φ _{RM_PV} (n)<φ _{RM_SP_H} (n) In the area, “2↑” is described. Further, in the area of t _{RM_SP_L} (n)<t _{RM_PV} (n)<t _{RM_SP_H} (n) and φ _{RM_SP_L} (n)<φ _{RM_PV} (n)<φ _{RM_SP_H} (n), “None” is described. The indoor air conditioning state determination table is held in the memory of the central controller 3, for example.

In step S306, the central controller 3 stores the determination result for the temperature and relative humidity of the n-th room, which is performed in step S305. In step S307, when the determination of all the rooms to be air-conditioned by the air conditioning system 1 is completed (YES in S307), the process proceeds to step S308. When the determination of all the rooms to be air-conditioned by the air conditioning system 1 has not been completed (NO in S307), the process returns to step S301.

From step S308 to step S314, the central controller 3 performs step S30.
It is determined whether or not to change the refrigerator chilled water outlet temperature based on the determination results for the temperature and relative humidity in each room stored in the process of 6.

In step S308, the central controller 3 determines whether or not there is a room belonging to the region in which "1↓" is described in the indoor air conditioning state determination table in the determination result stored in step S306. If there is a room belonging to the area in which the determination result is "1↓" (YES in S308), the process proceeds to step S308A. When there is no room belonging to the area in which the determination result is "1↓" (NO in S308), the process proceeds to step S309.

In step S308A, the central controller 3 changes the setting value of the memory of the refrigerator cold water outlet temperature output to the heat source controller 21 in step S106 so that the refrigerator cold water outlet temperature decreases by 0.5°C. However, if the refrigerator cold water outlet temperature falls below the lower limit value of the refrigerator cold water outlet temperature registered in the setting file when lowered by 0.5° C., the central controller 3 changes the setting of the refrigerator cold water outlet temperature to the lower limit value. .. After that, the process ends.

In step S309, the central controller 3 determines whether or not there is a room that has belonged to the area marked "2↓" in the indoor air-conditioning state determination table twice in a row in the determination result stored in step S306. To judge. When there is a room belonging to the area described as "2↓" twice in succession (YES in S309), the process proceeds to S309A. When there is no room that belongs to the area described as "2↓" twice in a row (YES in S309), the process proceeds to S310.

In step S309A, the central controller 3 changes the setting value of the memory of the refrigerator cold water outlet temperature output to the heat source controller 21 in step S106 so that the refrigerator cold water outlet temperature decreases by 0.5°C. However, if the refrigerator cold water outlet temperature falls below the lower limit value of the refrigerator cold water outlet temperature registered in the setting file when lowered by 0.5° C., the central controller 3 changes the setting of the refrigerator cold water outlet temperature to the lower limit value. .. After that, the process ends.

In step S310, the central controller 3 determines whether or not there is a room belonging to the area described as "2↓" in the indoor air-conditioning state determination table in the determination result stored in step S306. When there is a room belonging to the area described as "2↓" (YES in S310), the process proceeds to step S310A. When there is no room belonging to the area described as "2↓" (NO in S310), the process proceeds to S311.

In step S310A, the central controller 3 does not change the refrigerator cold water outlet temperature. After that, the process ends.

In step S311, the central controller 3 determines whether or not there is a room belonging to the area described as “none” in the indoor air conditioning state determination table in the determination result stored in step S306. When there is a room belonging to the area described as “none” (YES in S311), the process proceeds to step S311A. When there is no room belonging to the area described as “none” (NO in S311), the process proceeds to step S312.

In step S311A, the central controller 3 does not change the refrigerator cold water outlet temperature. After that, the process ends.

In step S312, the central controller 3 determines whether or not there is a room belonging to the area described as "1↑" in the indoor air conditioning state determination table in the determination result stored in step S306. When there is a room belonging to the area described as “1↑” (S312)
YES), the process proceeds to step S312A. If there is no room belonging to the area described as "1↑" (NO in S312), the process proceeds to step S313.

In step S312A, the central controller 3 changes the setting value of the memory of the refrigerator cold water outlet temperature output to the heat source controller 21 in step S106 so that the refrigerator cold water outlet temperature rises by 0.5°C. However, when the refrigerator cold water outlet temperature increased by 0.5°C exceeds the upper limit value (CS _Lim ) of the refrigerator cold water outlet temperature, the central controller 3 changes the setting of the refrigerator cold water outlet temperature to the upper limit value. After that, the process ends.

In step S313, the central controller 3 belongs to the area described as "2↑" and the area described as "2↑" in the indoor air conditioning state determination table in the determination result stored in step S306. Determines whether or not there is a room that is not twice consecutive. When there is a room that belongs to the area described as “2↑” and does not belong to the area twice (YES in S313), the process proceeds to step S313A. If there is no room that belongs to the area described as “2↑” and that does not belong to the two consecutive times (NO in S313), the process proceeds to step S314.

In step S313A, the central controller 3 does not change the refrigerator cold water outlet temperature. After that, the process ends.

In step S314, the central controller 3 determines that, in the determination result stored in step S306, all the rooms to be air-conditioned belong to the area marked "2↑" in the indoor air-conditioning state determination table twice in a row. Determine whether or not When all the rooms to be air-conditioned belong to the area described as "2↑" twice in succession (YES in S314), the process proceeds to step S314A. When there is a room that does not belong to the area described as “2↑” twice in a row (NO in S314), the process ends.

In step S314A, the central controller 3 changes the setting value of the memory of the refrigerator cold water outlet temperature output to the heat source controller 21 in step S106 so that the refrigerator cold water outlet temperature rises by 0.5°C. However, when the refrigerator cold water outlet temperature increased by 0.5°C exceeds the upper limit value (CS _Lim ) of the refrigerator cold water outlet temperature, the central controller 3 changes the setting of the refrigerator cold water outlet temperature to the upper limit value. After that, the process ends.

The central controller 3 determines whether to change the refrigerator chilled water outlet temperature based on the indoor condition acquired from the air conditioner controller 14 and the allowable range set in step S303 of FIG. 7. Therefore, the central controller 3 can optimize the refrigerating machine chilled water outlet temperature in a more realistic form than the case where control is performed based on the virtual room design condition, and improvement in COP of the entire air conditioning system 1 can be expected. ..

<Step S104>
In step S104, the central controller 3 infers the cooling tower cooling water outlet temperature (cooling water temperature). The central controller 3 assumes an approach temperature, which is a parameter for determining the cooling water temperature, within a predetermined range. The central controller 3 calculates the energy consumption of the air conditioning system 1 from the cooling water temperature determined according to the outside air condition for each assumed approach temperature, and determines the cooling water temperature that minimizes the energy consumption. The central controller 3 changes the setting value of the memory of the cooling water temperature output to the cooling tower controller 32 in step S106 so that it is controlled by the determined cooling water temperature.

In the inference of step S104, the central controller 3 assumes the approach temperature within a predetermined range and optimizes the cooling water temperature while suppressing the calculation amount. If the cooling water temperature is optimized, the operating efficiency of the cooling tower 30 is increased, and the COP of the entire air conditioning system 1 can be expected to be improved.

8 to 10 are diagrams for explaining the inference of the cooling water temperature based on the approach temperature. FIG. 8: is a figure which illustrates the item used for inference of a cooling tower and cooling water temperature. The parameter for inferring the cooling water temperature of the cooling tower is the cooling tower approach temperature _TAP (°C). The input items are the outside air wet bulb temperature T _WB (° C.), the cooling tower heat radiation amount q _CT (kW), and the cooling water inlet temperature T _CDR (° C.). The central controller 3 optimizes the cooling water flow rate Q _CD (L/min) and the cooling tower fan air flow rate G (m ³ /h) based on the above input items. During the optimization, the cooling water flow rate Q _CD is controlled in the range of 50 to 100%. The cooling tower fan air flow rate G is controlled in the range of 20 to 100%. The central controller 3 calculates the amount of energy consumption such as the power of the cooling water circulation pump 51 and the power of the cooling tower fan 31 from the cooling water flow rate Q _CD and the cooling tower fan air volume G, and the heat source system (air conditioning system 1 ) COP is evaluated. The cooling water temperature _TCDS (° C.) when the energy consumption of the air conditioning system 1 is minimum, that is, the COP of the air conditioning system 1 is maximum is output as an output item.

FIG. 9 is a graph illustrating the range of the cooling water temperature based on the outside air wet bulb temperature and the approach temperature. In the graph of FIG. 9, the vertical axis represents the cooling water temperature and the horizontal axis represents the outside air wet bulb temperature. The approach temperature is assumed to be in the range 2°C to 5°C. The cooling water temperature is calculated as a temperature obtained by adding the approach temperature to the outside air wet bulb temperature. The operating flow rate load factor of the cooling tower 30 is assumed to be 40% to 100%.

In the example of FIG. 9, the optimum operating range for the cooling water temperature of the cooling tower 30 is the range obtained by adding the approach temperature of 2° C. to 5° C. to the outside air wet bulb temperature. When the outside air wet bulb temperature changes in the range of 10° C. to 27° C., the cooling water temperature is in the range of 12° C. to 32° C. according to the approach temperature, and the control target value of the cooling water temperature is set. For example, when the outside air wet bulb temperature is 16°C, the control target value of the cooling water temperature is in the range of 18°C to 21°C. If the approach temperature is assumed to be in the range of 2°C to 5°C, for example, in increments of 0.5°C, the control target values of the cooling water temperature are 18°C, 18.5°C, ..., 21°C in increments of 0.5°C. It becomes the value of. The central controller 3 calculates the energy consumption amount of the air conditioning system 1 for each control target value, and determines the control target value when the calculated energy consumption amount is the minimum, as the cooling water temperature to be set.

FIG. 10 is a flowchart illustrating the flow of the cooling water temperature inference process. FIG. 10 is a diagram illustrating an example of details of the process of S104. The inference process of the cooling water temperature is executed by the central controller 3 at predetermined intervals, for example, every 10 minutes. Further, the inference process of the cooling water temperature may be started when the central controller 3 detects a change in the outside air condition.

In step S401, the central controller 3 calculates the outside air wet bulb temperature from the measured outside air dry bulb temperature and outside air relative humidity. The outside air wet bulb temperature can be calculated from the saturated water vapor pressure, the water vapor partial pressure, the absolute temperature, and the enthalpy obtained from the outside air dry bulb temperature and the outside air relative humidity.

In step S402, the central controller 3 assumes an approach temperature that is a parameter for inferring the cooling water temperature of the cooling tower 30. The approach temperature is assumed to be in the range of 2° C. to 5° C. at intervals of 0.5° C., and the energy consumption of the air conditioning system 1 is calculated for each approach temperature.

In step S403, the central controller 3 calculates the cooling water temperature as the control target value from the outside air wet bulb temperature calculated in step S401 and the approach temperature assumed in step S402.

Steps S404 to S407 are processes for calculating the power of the cooling water circulation pump 51 of the refrigerator 20. In step S404, the central controller 3 calculates the heat radiation amount of the entire system to be radiated by the cooling tower 30 (hereinafter, simply referred to as “heat radiation amount”) from the operating load ratio of each operating refrigerator 20.

In step S405, the central controller 3 obtains the cooling water inlet/outlet temperature difference of the refrigerator 20 from the heat radiation amount calculated in step S404. The cooling water inlet/outlet temperature difference changes depending on the cooling water flow rate, and if the cooling water flow rate decreases, the staying time of the cooling water staying in the condenser of the refrigerator 20 becomes long, so the cooling water inlet/outlet temperature difference of the refrigerator 20 becomes large. .. Therefore, the central controller 3 calculates the cooling water inlet/outlet temperature difference that affects the calculation of the cooling water flow rate from the heat radiation amount calculated in step S404 in consideration of the influence on the COP due to the increase or decrease of the cooling water flow rate. ..

In step S406, the central controller 3 calculates the cooling water flow rate. The cooling water flow rate is calculated from the heat radiation amount calculated in step S404 and the cooling water inlet/outlet temperature difference calculated in step S405.

In step S407, the central controller 3 calculates the power of the cooling water circulation pump 51 of the refrigerator 20 from the cooling water flow rate calculated in step S406.

Steps S408 to S411 are processes for calculating the air volume of the cooling tower fan 31. In step S408, the central controller 3 calculates the cooling water inlet temperature of the cooling tower 30 from the cooling water temperature calculated in step S403 and the cooling water inlet/outlet temperature difference of the refrigerator 20 calculated in step S405.

In step S409, the central controller 3 calculates the inlet air enthalpy of the cooling tower 30 from the cooling water inlet temperature calculated in step S408. In step S410, the central controller 3 calculates the outlet air enthalpy of the cooling tower 30 from the cooling water temperature calculated in step S403.

In step S411, the central controller 3 calculates the air volume of the cooling tower fan 31 from the heat radiation amount calculated in step S404, the inlet air enthalpy calculated in step S409, and the outlet air enthalpy calculated in step S410.

In step S412, the central controller 3 verifies whether the air volume G of the cooling tower fan 31 calculated in step S411 is equal to or less than the rated air volume G ₀ of the cooling tower 30. The rated air volume G ₀ is an air volume calculated based on the flow rate of the cooling water, the heat radiation amount, and the like. The central controller 3 calculates the energy consumption of the air conditioning system 1 when the air volume G of the cooling tower fan 31 is less than or equal to the rated air volume G ₀ . On the other hand, when the air volume G of the cooling tower fan 31 is larger than the rated air volume G ₀ , the central controller 3 returns to step S402, assumes the next approach temperature, and repeats the processing from step S403. The central controller 3 can suppress the calculation amount by not executing the calculation process when the air amount G of the cooling tower fan 31 is larger than the rated air amount G ₀ .

In step S413, the central controller 3 calculates the power of the cooling tower fan 31 from the air volume of the cooling tower fan 31 calculated in step S411.

In step S414, the central controller 3 causes the cooling water circulation pump 51 power calculated in step S407, the cooling tower fan 31 power calculated in step S413, the power consumption of the refrigerator 20, and the refrigerator 20 to circulate cold water. The total value of the power consumption of the pump (cold water primary pump 41) provided for is calculated as the power consumption of the air conditioning system 1. The central controller 3 repeats the process of calculating the power consumption of the air conditioning system 1 for each approach temperature assumed in step S402 only under the condition that step S412 is satisfied, and stores the power consumption of the air conditioning system 1 in the memory. .. Then, the central controller 3 selects the approach temperature that minimizes the power consumption of the air conditioning system 1 from the power consumption stored in the memory. At that time, the central controller 3 uses the cold water temperature estimated in step S103, and selects the approach temperature that minimizes the power consumption of the air conditioning system 1 in the case of the estimated cold water temperature. Then, the central controller 3 obtains a value obtained by adding the approach temperature to the outside air wet bulb temperature as the cooling water temperature, and determines this value as the control value. The central controller 3 changes the setting value of the memory of the cooling water temperature output to the cooling tower controller 32 in step S106 so that it is controlled by the determined cooling water temperature. As a result, the approach temperature in the case of the estimated cold water temperature is selected, so the amount of calculation is suppressed compared to the case where the calculation process is performed regardless of whether it is within the range of the cooling water temperature that can be cooled by the cooling tower. It The cooling tower controller 32 performs control so that the cooling water temperature that reduces the energy consumption of the entire air conditioning system becomes the control value sent from the central controller 3 even when the outside air temperature is high and the heat load is high. Will be seen.

<Step S105>
In step S105, the central controller 3 infers the number of operating refrigerators 20. The central controller 3 deduces the operating number of the refrigerator 20 based on the operation design sheet created in advance. The operation design sheet includes operation information that specifies the number of operating refrigerators 20 that minimizes the energy consumption of the air conditioning system 1 for each operating condition (refrigerator chilled water outlet temperature and cooling tower cooling water outlet temperature). Yes, it is created in advance based on performance data of the refrigerator 20 according to operating conditions and characteristic data of each device such as a pump and a fan. The characteristic data is, for example, data indicating power with respect to the performance of each device such as the discharge amount of the pump. The refrigerator 20 is an example of a “heat source device”. The operation design sheet is an example of “operation information”.

The central controller 3 determines the refrigerator 20 that minimizes the energy consumption of the air conditioning system 1 from the operation design sheet created in advance based on the refrigerator chilled water outlet temperature and the chilled water temperature inferred in steps S103 and S104. Get the number of operating vehicles. The central controller 3 changes the set value of the memory of the operating number of the refrigerator 20 output to the heat source controller 21 in step S106 so that the central controller 3 is controlled by the acquired operating number of the refrigerator 20.

In the inference of step S105, the central controller 3 attempts to optimize the number of operating refrigerators 20 by acquiring operation information according to operating conditions from an operation design sheet created in advance. If the number of operating refrigerators 20 is optimized, the operating efficiency of refrigerators 20 will be increased, and COP of the entire air conditioning system 1 can be expected to improve.

The operation design sheet referred to by the central controller 3 in step S105 is created as follows, for example. 11 to 17 are diagrams for explaining the creation of the operation design sheet for inferring the operating number of the refrigerator 20. FIG. 11 is a diagram for explaining calculation of power consumption of the refrigerator for each operating condition. The partial load characteristic diagram (hereinafter, also referred to as performance data) according to the model and capacity of the refrigerator 20 (heat source) is given by the manufacturer of the refrigerator 20 or by actual measurement. The performance data is a diagram showing changes in the COP of the refrigerator 20 alone with respect to the load factor of the refrigerator 20 alone for each refrigerator 20, for each cold water temperature, and for each cooling water temperature. The performance data of the refrigerator 20 of the type to which the performance data is not given in advance can be complemented based on the performance data prepared in advance as the reference data. Further, the cold water temperature for which the performance data is not given in advance and the performance data for the cooling water temperature can be interpolated based on the performance data for the temperatures before and after. By complementing or interpolating the lacking performance data with respect to the existing performance data, for each refrigerator 20, for example, the cooling water temperature is in increments of 1° C. and the cooling water temperature is in increments of 0.5° C. Be prepared. The central controller 3 or another computer used to create the operation design sheet can calculate the power consumption of each refrigerator 20 for each operating condition from the prepared performance data. The calculated power consumption of each refrigerator 20 is used to identify the number of operating refrigerators 20.

FIG. 12 is a diagram for explaining calculation of power consumption of the auxiliary machine for each load factor of the refrigerator. With respect to auxiliary equipment such as various pumps and various fans provided in the cooling tower 30 and the refrigerator 20, each auxiliary equipment is provided for each load factor of the refrigerator 20 based on the control system and characteristic diagram (characteristic data) of each auxiliary equipment. Calculate the power consumption of the machine and create a list of power consumption. The created list of power consumption of auxiliary machines is used to specify the number of operating refrigerators 20.

FIG. 13 is a diagram for explaining the complementation of the performance characteristic data. Hereinafter, the performance characteristic data is also simply referred to as performance data. When creating the operation design sheet, the performance data for each operating condition of the reference refrigerator 20 is registered in advance in the computer used to create the operation design sheet (hereinafter simply referred to as “computer”). .. When the performance data for the refrigerator 20 to be evaluated is insufficient, the computer compares the existing performance data for the refrigerator 20 to be evaluated with the reference data of the same operating condition to grasp the difference. The computer complements the performance data of the evaluation target refrigerator 20 under the operating conditions based on the ascertained difference from the reference data under the operating conditions where the performance data does not exist for the evaluation target refrigerator 20. By supplementing the performance data, the computer can infer the power consumption of the refrigerator 20 for each operating condition, and identify the number of operating refrigerators 20 that minimizes the energy consumption of the air conditioning system 1.

FIG. 14: is a figure which illustrates the operation priority of a refrigerator. The operation priority of the refrigerator 20 is periodically changed by the facility manager, or automatically changed by the central controller 3 or its management device according to the operating time of the air conditioning system 1. Since each refrigerator 20 has different performance, the number of operating refrigerators 20 that minimizes the energy consumption of the air conditioning system 1 also differs depending on the operation priority. Therefore, the operation design sheet is created for each combination of the driving priorities.

FIG. 14 shows, in a tabular form, an example of a combination of operation priorities for three refrigerators 20 (heat source 1, heat source 2, heat source 3). When there are three refrigerators 20, there are six combinations of operation priorities. In the table of FIG. 14, the left column is a name for identifying the operation design sheet. For example, in the operation design sheet TR_MAP_132 described in the second row, the operation priority order is heat source 1, heat source 3, heat source 2 in this order. It is an operation design sheet in some cases. The central controller 3 monitors the operation priority of the refrigerator 20, and when there is a change in the priority due to rotation or maintenance of the refrigerator 20, the central controller 3 refers to the corresponding operation design sheet to refer to the refrigerator 20. Infer the number of vehicles in operation.

FIG. 15 is a diagram illustrating an operation design sheet. In the example of FIG. 15, the operation design sheet is created for each cold water temperature, and the operating number according to the heat source (refrigerator 20) load factor is specified for each cooling water temperature. Specifically, when the chilled water temperature is 7° C. and the chilled water temperature is 24° C., the number of operating refrigerating machines 20 in which the energy consumption of the air conditioning system 1 is the minimum is 2 when the heat source load factor is 33% or more, 55% or more and 3 units. In this way, by defining the number of operating refrigerators 20 having the highest COP of the entire air conditioning system 1 from the cold water temperature and the cooling water temperature in such an operation design sheet created in advance, the central controller 3 It is possible to realize the control of the number of operating refrigerators 20 based on the cold water temperature and the cooling water temperature information obtained from the heat source controller 21 and the like.

FIG. 16 is a graph illustrating an increase in the number of operating heat sources. The vertical axis represents the number of operating heat sources, and the horizontal axis represents the heat source load factor. FIG. 16 is a graph showing an example of the cold water temperature of 7° C. and the cooling water temperature of 24° C. shown in FIG. The heat source operation priority is in the order of heat source 1, heat source 2, and heat source 3, and the number of heat source operating units is controlled based on the corresponding operation design sheet. P1 shown on the horizontal axis is a threshold value of the heat source load factor when increasing the number of heat source operating units from one to two. In the example of FIG. 16, P1 is 33%, and when the heat source load factor is 33% or more, the number of operating units is increased from 1 to 2, and when the heat source load factor is less than 33%, the operating number is from 2 units. The number of stages is reduced to one. Similarly, P2 shown on the horizontal axis is a threshold value of the heat source load factor when the number of operating heat source is increased from 2 to 3. In the example of FIG. 16, P2 is 55%, and when the heat source load factor is 55% or more, the number of operating units is increased from 2 to 3, and when the heat source load factor is less than 55%, the operating number is from 3 units. The number of stages is reduced to two. The heat source load factor thresholds (hereinafter, also referred to as increasing/decreasing stage points) P1 and P2 for controlling the number of operating units are based on the measurement data of the heat source load factor and conditions such as whether the heat source load factor is increasing or decreasing. Specified.

FIG. 17 is a graph showing an example of the correlation between the load factor of the entire heat source and the COP of the entire system. The vertical axis represents the COP of the heat source system, and the horizontal axis represents the load factor of the entire heat source. The equipment assumed in the creation of the graph in FIG. 17 is an inverter system, and each includes a turbo refrigerator, a chilled water pump, a chilled water pump, and two integrated cooling towers. The cold water temperature is assumed to be 7°C. The value indicated by the arrow in the figure indicates the increase/decrease stage point of the heat source. As can be seen from the graph of FIG. 17, as the temperature of the cooling water decreases, the increase/decrease stage point shifts to the low load factor side. This is because the performance diagram of the heat source alone shifts the maximum efficiency point to the low load factor side as the cooling water temperature decreases. Therefore, in the operation design sheet used for the central controller 3, the increase/decrease stage points of the heat source are set to slightly different positions for each cooling water temperature, as shown in the graph of FIG.

FIG. 18 is a flowchart illustrating a process of creating an operation design sheet. The computer used to create the operation design sheet performs the following processing before starting the operation of the air conditioning system 1 to create the operation design sheet. The computer also executes the following processing when recreating the operation design sheet when the configurations of the refrigerator 20, the cooling tower 30, and the auxiliary equipment included in the air conditioning system 1 are changed. The created operation design sheet is stored in the auxiliary storage device included in the computer or the central controller 3. The auxiliary storage device included in the central controller 3 is an example of a “storage unit”.

In step S501, the computer reads the configuration of the heat source system (air conditioning system 1). Specifically, the computer reads information such as the number of auxiliaries such as the refrigerator 20, the cooling tower 30, various pumps, and various fans that compose the air conditioning system 1.

In step S502, the computer repeats the processing from step S503 to step S507 at a temperature of 0.5° C. to 12° C. within a range of 5° C. to 12° C., for example, at intervals of 0.5° C. That is, an operation design sheet is created for each cold water temperature of 0.5°C. The operation design sheet is not limited to the case where the cold water temperature is created every 0.5°C. By creating the operation design sheet at a narrower temperature interval, the accuracy of inferring the number of operating heat sources (refrigerator 20) is improved. Further, the computer may create the operation design sheet for each preset cold water temperature instead of for each equally spaced cold water temperature. As a result, it is possible to create a flexible operation design sheet according to the configuration of the air conditioning system 1.

In step S503, the computer repeats the processing from step S504 to step S506 at a temperature of the cooling water temperature (cooling tower cooling water outlet temperature) in the range of 12° C. to 34° C., for example, at intervals of 1° C. That is, the computer repeats the process of inferring the number of operating heat sources according to the heat source load factor for each cooling water temperature at 1° C. intervals. The inference of the number of operating heat sources is not limited to the cooling water temperature of 1° C., but may be inferred for each preset cooling water temperature. As can be seen from FIG. 17, in the heat source alone, the highest efficiency point (the highest point of the convex portion on the left side of the graph) shifts to the low load factor side as the cooling water temperature decreases, so that the computer, for example, In consideration of the deviation, it is possible to set the cooling water temperature that infers the number of operating heat sources.

In step S504, the computer calculates the number of operating heat sources that minimizes the energy consumption of the air conditioning system 1 for each heat source load factor at intervals of 10% within the range of the heat source load factor of 20% to 100%. Repeat the process. The calculation of the number of operating heat sources is not limited to 10% intervals. In the range of the heat source load factor before and after the calculated number of operating heat sources is switched, the computer calculates the number of operating heat sources at 1% intervals, for example. Good.

In step S505, the computer sets the cold water temperature (5 to 12° C.) set in step S502, the cooling water temperature (12 to 34° C.) set in step S503, and the heat source total load set in step S504. Based on the ratio (20% to 100%), that is, using these values as parameters, the number of operating heat sources that minimizes the energy consumption of the air conditioning system 1 is calculated under the combined conditions of these values. Specifically, first, referring to the device information (characteristic data as shown in FIG. 11 and FIG. 12) read in step S501, the set cold water temperature, the cooling water temperature, and the heat source overall load factor are set. The corresponding COP value of the refrigerator alone and the power consumption values of the pump and fan are read out. The power consumption of the refrigerator is calculated based on the COP of the refrigerator alone and the heat source load factor. Then, the value of the power consumption of the refrigerator alone and the total value of the power consumption of the pump and the fan are calculated as the energy consumption. The computer performs the above-described calculation process for all the cold water temperatures and the combined conditions of the cooling water temperature and the heat source overall load factor. Then, the computer stores the energy consumption amount calculated for each combination condition in the auxiliary storage device as a calculation result under the combination condition. Next, when there are two or more heat sources, the power consumption value of each heat source is calculated individually based on the value obtained by dividing the overall heat source load factor by the number of heat sources. The value of the power consumption of the plurality of heat sources is added to the power consumption of the pump and the fan to obtain the energy consumption. When the priority of the heat source is set, such as when the performance of the heat source is different, the power consumption of the heat source is calculated individually according to the priority. When there are two or more heat sources, the energy of the air conditioning system 1 in the case where there are two or more heat sources is described above for all of the combination patterns of a plurality of heat sources (when there is one heat source or when there are two or more heat sources). Calculate consumption. Then, for all the combination conditions of the cold water temperature, the cooling water temperature, and the heat source overall load factor, the energy consumptions in all the combination patterns of the plurality of heat sources are mutually compared, and the operation of the heat source when the energy consumption is the minimum is performed. The number of units is selected as the number of operating heat sources under the combined conditions of the cold water temperature, the cooling water temperature, and the heat source overall load factor, and this operating number is stored in the auxiliary storage device. In this way, the number of operating heat sources according to the cooling water temperature and the overall heat source load factor is calculated for each cold water temperature, and the calculated number of operating heat sources is stored in a table, that is, an operation design sheet as shown in FIG. .. The power consumption of the cooling water circulation pump 51, the power of the cooling tower fan 31, and the load factor of the chilled water primary pump 41 are assumed to be the same as the heat source overall load factor of the refrigerator 20.

In step S506, the computer determines whether or not the calculation for calculating the operating number has been completed for each heat source load factor within the range specified in step S504. When the calculation for calculating the operating number for each heat source load factor is completed (S506; YES), the process proceeds to step S507. If the calculation for calculating the number of operating heat sources for each heat source load factor is not completed (S506; NO), the process returns to S504, and the process of S505 is executed for the next heat source load factor.

In step S507, the computer determines whether or not the calculation for calculating the operating number for each heat source load factor has been completed for each cooling water temperature within the range specified in step S503. When the calculation for each cooling water temperature is completed (S507; YES), the process proceeds to step S508. When the calculation for each cooling water temperature is not completed (S507; NO), the process returns to S503, and the processes from S504 to S506 are executed for the next cooling water temperature.

In step S508, the computer determines whether or not the calculation for calculating the number of operating units has been completed for each cooling water temperature and each heat source load factor for each cooling water temperature within the range specified in step S502. When the calculation for each cold water temperature is completed (S508; YES), the process proceeds to step S509. When the calculation for each cooling water temperature is not completed (S508; NO), the processing returns to S502, and the processing from S503 to S507 is executed for the next cooling water temperature.

In step S509, the computer completes the operation design sheet of the air conditioning system 1 for each heat source operation priority pattern. Specifically, the computer specifically identifies, from the information on the number of operating heat sources calculated in step S505, the increase/decrease stage point for controlling the number of operating heat sources based on the measured value of the heat source load factor, and displays the operation design sheet. Finalize. As described above, the operating number of the refrigerator 20 that is the heat source can be obtained based on the information of the devices that configure the air conditioning system 1, even if the outside air condition that is an environmental variable is not given. It is possible to calculate and save in advance before starting.

When the amount of reduction in power consumption is roughly estimated, it depends on the device configuration and various conditions of the entire system, but the central controller 3 adjusts the set value of the refrigerator cold water outlet temperature as described above, the number of operating refrigerators 20. According to the calculation result, it is possible to reduce the power consumption by more than ten percent as compared with the case where such adjustment is not performed.

1・・Air conditioning system: 2・・Network: 3・・Central controller: 4・・Indoor: 10・・Air conditioner: 11・・Coil: 12・・Electric fan: 13・・Air conditioner cold water flow control valve: 14・・Air conditioner controller: 20 ・・Refrigerator: 21 ・・Heat source controller: 30 ・・Cooling tower: 31 ・・Cooling tower fan: 32 ・・Cooling tower controller: 40 ・・Cold water circulation system: 41 ・・Cold water 1 Next pump: 42 ·· Cold water secondary pump: 43 · · Minimum flow valve: 44 · · Secondary pump controller: 50 · · Cooling water circulation system: 51 · · Cooling water circulation pump

Claims (7)

A control device for an air conditioning system having a heat source device and a cooling tower,
Based on the information of at least the outside air and the heat load, the air conditioner estimates the cold temperature which can meet the room conditions,
Based on at least the outside air and information of each device of the air conditioning system and the estimated cold water temperature, estimate the cooling water temperature at which the energy consumption of the entire air conditioning system becomes small ,
Controls the cooling tower based on the coolant temperature and the estimated, controls the heat source apparatus based on the cooling water temperature and the estimated and the estimated temperature of chilled water,
Control device for air conditioning system. In the estimation of the cold water temperature, the air conditioner adopts a high value in a range in which indoor conditions can be satisfied by control,
The control device for the air conditioning system according to claim 1. In the estimation of the cooling water temperature, the energy consumption of the entire air conditioning system at each of several assumed cooling water temperatures is calculated, and the cooling water temperature at which the calculated energy consumption becomes small is adopted.
The control device of the air-conditioning system according to claim 1. The information on the heat load is information on the operating state acquired from the heat source device,
The control device for the air-conditioning system according to any one of claims 1 to 3. A method for controlling an air conditioning system having a heat source device and a cooling tower, comprising:
Based on the information of at least the outside air and the heat load, the air conditioner estimates the cold temperature which can meet the room conditions,
Based on at least the outside air and information of each device of the air conditioning system and the estimated cold water temperature, estimate the cooling water temperature at which the energy consumption of the entire air conditioning system becomes small ,
Controls the cooling tower based on the coolant temperature and the estimated, controls the heat source apparatus based on the cooling water temperature and the estimated and the estimated temperature of chilled water,
Air conditioning system control method. A control program for an air conditioning system having a heat source unit and a cooling tower,
In the control device of the air conditioning system,
Based on the information of at least the outside air and the thermal load, and processing the air conditioner to estimate the temperature of chilled water that can meet the room conditions,
Based on at least the outside air and information of each device of the air conditioning system and the estimated cold water temperature, a process of estimating a cooling water temperature at which the energy consumption of the entire air conditioning system becomes small ,
The estimated causes on the basis of the coolant temperature is controlled the cooling tower, to execute a process for controlling the heat source apparatus based on the cooling water temperature and the estimated cold water temperature as the estimated,
Air conditioning system control program. A heat source device, a cooling tower, and a control device,
The control device is
Based on the information of at least the outside air and the heat load, the air conditioner estimates the cold temperature which can meet the room conditions,
Based on at least the outside air and information and the estimated cold water temperature of each equipment air-conditioning system, to estimate the cooling water temperature of the energy consumption of the entire air conditioning system is reduced,
Controls the cooling tower based on the coolant temperature and the estimated, controls the heat source apparatus based on the cooling water temperature and the estimated and the estimated temperature of chilled water,
Air conditioning system.

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