JP2023033397A - Control device, control method and control program for air conditioning system and air conditioning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose an air-conditioning control technique capable of enhancing operation efficiency of a heat source in an air conditioning system in which an indoor temperature and relative humidity cannot be acquired.

SOLUTION: A control device for an air conditioning system includes storage means, first determination means and instruction means. The storage means stores information used for calculating an indoor condition that is assumed on the basis of design information on a heat source machine and includes a temperature of air supplied to an indoor side by an air conditioner and relative humidity. When an outside air condition including an acquired outside air temperature and relative humidity and the indoor condition calculated on the basis of the information satisfy a predetermined condition that does not require dehumidification of the outside air, the first determination means determines a temperature of cooling water to be supplied from the heat source machine to the air conditioner at a temperature allowing air supply enabling indoor sensible heat to be treated. The instruction means issues an instruction to a control controller of the heat source machine to set the temperature of the cooling water to be a determined temperature.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2023,JPO&INPIT

Description

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

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

JP-A-2005-257221 JP 2015-197236 A JP 2008-134013 A JP 2006-275397 A JP 2005-114295 A

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

With the development of electronic equipment and the demand for energy consumption reduction, various electronic controls are used in air conditioning systems in recent years. However, 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. In the case of an existing air conditioning system, the controller of the newly installed air conditioning system may not be able to obtain the indoor temperature and relative humidity. Therefore, the present application discloses a control technique for air conditioning that can improve the operating efficiency of heat source equipment in an air conditioning system that cannot obtain indoor temperature and relative humidity.

One aspect of the disclosed technology is a control device for an air conditioning system. The control device of the air conditioning system includes storage means, first determination means, and instruction means. The storage means stores information used for calculating indoor conditions including the temperature and relative humidity of the air supplied to the room by the air conditioner, assumed based on the design information of the heat source equipment. The first determination means determines from the heat source device, when the outside air condition including the obtained outside air temperature and relative humidity and the indoor condition calculated based on the information satisfy a predetermined condition that the outside air does not need to be dehumidified. The temperature of cold water to be supplied to the air conditioner is determined to be a temperature capable of supplying air capable of treating sensible heat in the room. The instruction means instructs the controller of the heat source equipment to set the temperature of the cold water to the determined temperature.

According to such an invention, even if the indoor temperature and relative humidity cannot be obtained, the control device determines whether dehumidification of the outside air is necessary or not based on the assumed indoor and outdoor air conditions based on the design information of the heat source equipment. can be determined. When dehumidification of the outside air is unnecessary and the air conditioning load is small, the controller can ignore the latent heat load in the room, and therefore determines the temperature of the chilled water that can process the sensible heat load in the room. That is, the control device can raise the temperature of the cold water by the amount that the latent heat load is not processed. This control device can increase the operating efficiency of the heat source equipment by increasing the temperature of the cold water.

Furthermore, the control device may have the following features. A first calculation means for calculating the absolute humidity of the outside air based on the temperature and the relative humidity of the outside air; a second calculation means for calculating the absolute humidity of the supplied air based on the temperature and the relative humidity of the supplied air; and satisfying the predetermined condition is when the absolute humidity in the room is higher than the absolute humidity in the outside air. According to this aspect of the invention, the control device can determine that dehumidification of the outside air is not necessary when the indoor absolute humidity of the supplied air is higher than the absolute humidity of the outside air.

Furthermore, the control device may have the following features. It further comprises a second determining means for determining the upper limit temperature of cold water supplied to the air conditioner by the heat source device based on the temperature of the outside air and the cooling performance of the heat source device, If the temperature is higher than the upper temperature limit, the chilled water temperature will be directed to the determined upper temperature limit. According to such an invention, the control device can suppress an increase in the indoor temperature caused by excessively increasing the temperature of the cold water.

Furthermore, the present invention can also be understood as an air conditioning system control method, an air conditioning system control program, and an air conditioning system.

The controller can determine the chilled water temperature that improves the COP of the entire air conditioning system in an air conditioning system that does not have a means of obtaining indoor temperature and relative humidity.

FIG. 1 is a diagram showing an example of an air conditioning system. FIG. 2 is an image of an overview of the 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 the inference flow of the chiller chilled water outlet temperature by the central controller. FIG. 5 is a diagram showing an example of a psychrometric chart. FIG. 6 is an example of a table for determining the refrigerator cold water outlet temperature based on the calculated amount of change in the refrigerator cold water outlet temperature. FIG. 7 is a second diagram illustrating the inference flow of the chiller chilled water outlet temperature by the central controller. FIG. 8 is a diagram illustrating the items used to infer the cooling tower and cooling water temperature. FIG. 9 is a graph illustrating ranges of coolant outlet temperatures based on ambient wet bulb temperature and approach temperature. FIG. 10 is a flowchart illustrating the flow of inference processing for the cooling water temperature. FIG. 11 is a diagram illustrating calculation of power consumption of a refrigerator for each operating condition. FIG. 12 is a diagram illustrating calculation of the power consumption of the auxiliary machine for each load factor of the refrigerator. FIG. 13 is a diagram illustrating complementation of performance characteristic data. FIG. 14 is a diagram illustrating the order of priority of operation of refrigerators. 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 processing for creating an operation design sheet.

Embodiments of the present invention will be described below. The embodiments shown below are examples of embodiments of the present invention, and the technical scope of the present invention is not limited to the following aspects.

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 the air in the room 4 passes, a refrigerator 20 (an example of the "heat source machine" referred to in the present application) that cools cold water sent to the air conditioner 10, 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 incorporates a coil 11 through which cold water passes through a pipe, and an inverter-controlled electric fan 12 . Cold water passing through the coil 11 of the air conditioner 10 is carried by a cold water circulation system 40 that forms a cold water circulation path between the air conditioner 10 and the refrigerator 20 . Cooling water for cooling 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 . Although one air conditioner 10 and two cooling towers 30 and two refrigerators 20 are shown in FIG. , 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 other various design factors.

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

The chilled water circulation system 40 includes a chilled water primary pump 41 installed on the inlet side of the refrigerator 20 and a chilled water secondary pump 42 installed on the inlet side of the header that branches the chilled water to each air conditioner 10. , a cold water primary pump 41 and a cold water secondary pump 42 forcibly circulate cold water. The chilled water primary pump 41 is a turbopump installed for the purpose of ensuring the flow velocity of chilled water passing through the tube side of the evaporator of the refrigerator 20, and is driven by an inverter-controlled motor whose rotational speed can be changed. One chilled 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 speed of cold water passing through the pipe of the coil 11 of the air conditioner 10, and is an inverter-controlled pump capable of changing the rotational speed, similar to the cold water primary pump 41. 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 single pump, the number and size of the air conditioners 10, and the like.

A secondary pump controller 44 is provided for the cold water secondary pump 42 . The secondary pump controller 44 receives control information sent from the host device via the network 2 and information on flow sensors and temperature sensors provided in each part of the cold water circulation system 40 . Based on this information, the secondary pump controller 44 determines the number of operating cold water secondary pumps 42, the rotation speed, 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. 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 speed of the cooling water passing through the tube side of the condenser of the refrigerator 20, and is driven by an inverter-controlled motor capable of changing the rotational speed. 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 . A ball-tap make-up water valve is provided inside the cooling tower 30 to maintain the water level of the cooling water, so that the suction pressure of the cooling water circulation pump 51 is kept substantially constant.

A heat source controller 21 is provided in the refrigerator 20 . The heat source controller 21 receives control information sent from the host device via the network 2, flow sensor information for measuring the flow rate of cooling water or cold water passing through the refrigerator 20, and temperature information for measuring the temperature of cooling water or cold water passing through the refrigerator 20. Sensor information is entered. Based on this information, the heat source controller 21 adjusts the rotation speed of the cooling water circulation pump 51, the rotation speed of the cold water primary pump 41, the rotation speed of the compressor that affects the performance of the refrigerator 20, and the opening of the vanes. . In addition, the heat source controller 21 transmits various information such as the measured value of the temperature sensor, the measured value of the flow rate sensor, the operating state of the cooling water circulation pump 51, the operating state of the cold water primary pump 41, and the operating state of the refrigerator 20 to the host device. It also has a function to send.

A cooling tower controller 32 is provided in the cooling tower 30 . The cooling tower controller 32 receives control information sent from the host device via the network 2, temperature sensor information for measuring the outside air temperature, humidity sensor information for measuring the outside air humidity, temperature of cooling water on the outlet side of the cooling tower 30, and The information of the temperature sensor that measures the is input. Based on this information, the cooling tower controller 32 adjusts the rotational speed of the motor that drives the cooling tower fan 31 provided in the cooling tower 30 . The cooling tower controller 32 also has a function of transmitting various kinds of information, such as the 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 cooling operation. That is, if the temperature in the room 4 is higher than the set temperature, the air conditioner controller 14 increases the opening degree of the air conditioner cold water flow rate adjustment valve 13, and if the temperature in the room 4 is lower than the set temperature, the air conditioner cold water flow rate adjustment valve 13 is opened. Decrease the degree of opening. Further, the heat source controller 21 sets the temperature of the chilled water on the outlet side of the refrigerator 20 (hereinafter referred to as “refrigerator chilled water outlet temperature”, sometimes simply “chilled water temperature”) to a predetermined control target value (for example, 7 °C), the capacity of the refrigerator 20 is adjusted. In addition, the cooling tower controller 32 controls 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”, sometimes simply “cooling water temperature”). The cooling tower fan 31 is rotated so that the condenser is below a predetermined set temperature at which it can exhibit 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 in the room 4, the temperature in the room 4 will remain the same as that of the air conditioner. 10 is kept substantially constant, the refrigerator cold water outlet temperature is kept substantially constant by the refrigerator 20, the refrigerator cooling water outlet temperature is kept within a range that does not hinder the operation of the refrigerator 20, and the entire system is stabilized. good driving is maintained.

The basic control contents of the air conditioning system 1 are as described above. 3, hereinafter referred to as the "Central Controller" for convenience. The central controller 3 takes in the minimum necessary parameters for control of general refrigerators, cooling towers, and air conditioners as input points, and based on these minimum necessary 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 conditioning equipment installed in a newly constructed building, but also to existing air conditioning equipment. Here, the power consumption taken into account in calculating the COP of the entire air conditioning system is the power consumption of the cooling water circulation pump 51, the power consumption of the cooling tower fan 31, the power consumption of the refrigerator 20, and the power consumption of the cold water primary pump 41. Maximizing the COP of the entire system corresponds to minimizing the total value of these power and power consumptions. Needless to say, the power of the cold water secondary pump 42 may be included.

FIG. 2 is an image of an overview of the control performed by the central controller 3. As shown in FIG. 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 central controller 3 executes the computer program, for example, in real time (every 10 minutes), the outside air conditions (outside air temperature and humidity), indoor conditions (indoor temperature and humidity), heat source load conditions (refrigerating machine manufacturing calorific value, etc.) are acquired from the controller of each device, and the operational state and device-specific The characteristic data showing the correlation with the COP of each device is read out, and the control target value of each device is optimized according to a predetermined rule engine. Then, the central controller 3 outputs the control target value of each device, which has been 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 the new control target value that has been optimized. As a result, the COP of the air conditioning system 1 as a whole is maximized by adjusting the control amount by the controller of each device toward the control target value subjected to the optimization processing.

FIG. 3 is a flow chart of control performed by the central controller 3 . When the computer program is executed, the central controller 3 reads a setting file (information such as the type and number of devices provided in the air conditioning system 1) stored in a recording medium such as a hard disk (S101). Next, the central controller 3 acquires values such as the outdoor air condition measured by the cooling tower controller 32, the indoor condition measured by the air conditioner controller 14, and the heat source load condition used by the heat source controller 21 from each controller. (S102). Next, the central controller 3 infers the chiller chilled water outlet temperature (heat source chilled water temperature) (S103). Also, the central controller 3 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). In addition, the central controller 3 outputs to the heat source controller 21 the chiller cold water outlet temperature inferred in the process of step S103 and the number of operating chillers 20 inferred in the process of step S105, and outputs the cooling tower temperature 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. If the determination is positive, the control of the air conditioning system 1 is stopped. 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 chiller cold water outlet temperature as described above. In this inference, when the indoor conditions cannot be obtained, the central controller 3 infers the chiller cold water outlet temperature based on the virtual room design conditions and the virtual air conditioner design. Further, when the information on the indoor temperature and relative humidity can be obtained, the central controller 3 infers the chiller cold water outlet temperature based on the state of change in the indoor temperature and relative humidity. In the inference of step S103, the central controller 3 determines whether dehumidification of outside air is necessary. When dehumidification of outside air is unnecessary 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 it is sufficient to process the sensible heat load in the room. Therefore, the central controller 3 optimizes the refrigerator cold water outlet temperature by determining the operating conditions of the air conditioner 10 that can process the indoor sensible heat load. By optimizing the refrigerator cold water outlet temperature, the operating efficiency of the refrigerator 20 is increased, and an improvement in the COP of the entire air conditioning system 1 can be expected. The central controller 3 performs the inference processing in step S103 in real time (every 10 minutes, for example). When estimating the cooling water temperature in step S104, the central controller 3 selects the cooling water temperature that minimizes the total power consumption based on the estimated cold water temperature.

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

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. FIG. The central controller 3 also refers to the design information of the virtual air conditioner determined based on the heat source design. The central controller 3 controls the indoor temperature and relative humidity set as control target values based on the heat source load conditions, the outside air conditions, and the capacity of the virtual air conditioner. The indoor temperature and relative humidity set as control target values are referred to herein as virtual indoor design conditions.

(Determination of design information for virtual air conditioners)
The central controller 3, as the design information of the virtual air conditioner, includes coil inlet water temperature t _w1 , coil outlet water temperature t _w2 , coil water flow rate L, coil heat quantity q _w , coil inlet air temperature t _a1 , coil outlet air temperature t _a2 and the supplied air volume G are determined as follows. The central controller 3 reads the setting file and sets the coil inlet water temperature t _w1 and coil outlet water temperature t _w2 of the coil 11 of the air conditioner 10 registered by 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 refrigerators 20 is 3, and the rated flow rate of the cold water secondary pump 42 is 4,030 L/min. and Further assume that the air conditioning system 1 comprises 100 virtual air conditioners.

A coil water flow rate L, which is the flow rate of cold water that flows through the coil 11 per minute, is calculated, for example, by the following formula.

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 flow rate of the coil 11 The amount of water L is calculated as 121 L/min. Also, the coil water heat quantity _qw , which is the heat quantity of the cold water flowing through the coil 11, is calculated by the following formula, for example.

According to Equation 2, based on the coil outlet water temperature t _w2 , the coil inlet water temperature t _w1 , and the coil water flow rate L, the coil water flow heat quantity q _w is calculated as 42.21 kW. The central controller 3 acquires 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 , from the air conditioner controller 14 . however,
When air is not yet flowing through the coil 11, such as when the air conditioning system 1 is to be operated from now on, the initial set values registered in the setting file are adopted as the coil inlet air temperature t _a1 and the coil outlet air temperature t _a2 . be done. Here, for example, the coil inlet air temperature t _a1 is set to 2
6°C, and 17.5°C as the coil outlet air temperature _ta2 . moreover,
Assume that the relative humidity of the air entering coil 11 is 50% RH.

FIG. 5 is a diagram showing an example of a psychrometric chart. The psychrogram is filled with state values indicating various air states including absolute humidity, relative humidity, dry bulb temperature and wet bulb temperature, and two state values are selected from these to determine the state of the air. It is a diagram created so that it can be grasped. 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 t _a1 is 26° C. and the relative humidity is 50%.
When the RH air is cooled to 17.5°C, the coil exit air temperature t _a2 , the relative humidity is 8
It turns out that it becomes 5%RH. Based on such assumptions, the supply air volume G of the virtual air conditioner is calculated by, for example, the following formula.

Cp in Equation 3 is the isobaric specific heat of the dry air, and ρ is the density of the dry air. From Equation 3, the air supply volume G of the virtual air conditioner is calculated to be 15,291 m ³ /h. Through the above processing, the central controller 3 can determine the design information of the virtual air conditioner. The central controller 3 that stores the determined design information of the virtual air conditioner is an example of the “storage means”.

(Virtual room design conditions)
Furthermore, the central controller 3 determines the virtual interior design conditions. In determining the virtual room design conditions, it is assumed that the control target room temperature is the coil outlet air temperature t _a2 and the room relative humidity is 85% RH, which is the relative humidity of the coil outlet air.

The central controller 3, which has completed the design of the virtual air conditioner and the virtual room design condition assumption processing through the above processing, performs the dehumidification determination in step S201. In this determination, the central controller 3 compares the absolute humidity of the outside air obtained from the heat source controller 21 of the cooling tower 30 with the indoor absolute humidity under the virtual room design conditions. First, the central controller 3 refers to the psychrometric diagram of FIG. 5 and calculates the indoor absolute humidity from the indoor temperature and humidity measured value. The central controller 3 compares the calculated absolute humidity of the indoor air and the absolute humidity of the outdoor 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 required (dehumidification is not required in S201), and the process proceeds to step S202. If the absolute humidity of the indoor air is greater than or equal to the absolute humidity of the outside air, the central controller 3 determines that dehumidification is required (dehumidification required in S201), and the process proceeds to step S205. The central controller 3 that calculates the absolute humidity of the outside air is an example of the "first calculation means". The central controller 3 that calculates the indoor absolute humidity under the virtual indoor design conditions is an example of the "second calculating means."

If it is determined in step S201 that the dehumidification of the outside air is unnecessary and the air conditioning load is small, the virtual air conditioner can ignore the latent heat load in the room. It should be able to handle the load. Therefore, in step S202, the central controller 3 calculates the chiller chilled water outlet temperature (chilled water temperature in the figure) that can process the indoor sensible heat load. The central controller 3 assumes the following items 1 to 6 in calculating a rational chiller cold water outlet temperature that maximizes the COP of the entire system.
1. The coil water flow heat quantity _qw is equal to the indoor heat load processing quantity _qa .
2. The coil water flow rate L is equal to the measured value.
3. The coil water inlet and outlet temperature difference (t _w2 - _{t w1} ) is equal to the measured value.
4. The amount of supplied air G is decreased according to the load. The lower limit α of the supplied air volume G is set to 20% of the rated value. The lower limit α of the air supply air volume 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 t _w1 is increased.
6. The upper limit of the coil inlet water temperature t _w1 is determined by Equation 4 below.

CS _Lim in Equation 4 is the upper limit of the coil inlet temperature (°C), t' is the outside air wet bulb temperature (°C), _tap is the cooling tower approach temperature (°C), and Δt _CDS-CS is the chiller cooling water inlet and chilled water It is the temperature difference (°C) at the outlet. Δt _CDS-CS is determined based on the capacity of the refrigerator 20, for example, and is set to 5° C. in this embodiment. In Equation 4, the cooling tower cooling water outlet temperature is calculated as 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 between the refrigerator cooling water inlet and the cold water outlet (Δt _CDS-CS ) considering the capacity of the refrigerator 20 with respect to the refrigerator cooling water inlet temperature. You can determine CS _Lim, which is the upper limit. For the lower limit of the coil inlet water temperature _tw1 , for example, the value registered in the setting file at the time of initial setting can be used. The central controller 3 that determines CS _Lim , which is the upper limit value of the coil inlet water temperature t _w1 , is an example of the "second determining means."

Based on the above assumptions, the chiller cold water outlet temperature capable of processing the indoor sensible heat load is determined, for example, by the following Equation 5.

In Equation 5, t _w1new is the refrigerator cold water outlet temperature (coil inlet water temperature) calculated this time, 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 is the air temperature. Δt ₁ is the minimum air volume temperature change indicating the temperature change of the air passing through the coil when the virtual air conditioner is operated at the minimum air volume 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 , and the value obtained by subtracting the minimum air flow temperature change Δt ₁ from the temperature change of the air that has passed through the coil is added. It is calculated by Note that the minimum air volume temperature change Δt ₁ is determined, for example, by Equation 6 below.

In Equation 6, qw is the amount of heat passed through the coil, α is the minimum air supply volume of the virtual air conditioner, G is the air supply volume of the virtual air conditioner, ρ is the density of the dry air, and Cp is the constant pressure specific heat of the dry air. The central controller 3 that executes the process of step S202 is an example of the "first determining means."

In step S203, the central controller 3 determines whether or not to change the refrigerator cold water outlet temperature. In the determination in step S203, the central controller 3 determines whether the temperature of the refrigerator cold water Determine whether to change the outlet temperature. That is, when the calculated chilled water temperature tends to rise, the central controller 3 changes the memory set value of the refrigerator chilled water outlet temperature output to the heat source controller 21 in step S106 so that the chilled water temperature rises. If the calculated cold water temperature tends to decrease, the central controller 3 changes the memory set value of the chiller cold water outlet temperature output to the heat source controller 21 in step S106 so that the temperature of the cold water decreases. FIG. 6 is an example of a table for determining the refrigerator cold water outlet temperature based on the calculated amount of change in the refrigerator cold water outlet temperature. In FIG. 6, 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. t _w1new in FIG. 6 is the refrigerator cold water outlet temperature calculated this time. t _w1old is the freezer cold water outlet temperature calculated last time. For example, in FIG. 6, if a state in which the difference between t _w1new and t _w1old is -1.0 or more and less than -0.5 consecutively occurs twice (in the case of No. 4 in FIG. 6), the central controller 3 is determined by subtracting 1.0° C. from the previously calculated temperature (t _w1old ) of the chilled water outlet temperature of the refrigerator as the chilled water outlet temperature of the refrigerator. The table illustrated in FIG. 6 is held on the memory of the central controller 3, for example. If the refrigerator cold water outlet temperature is to be changed (change permitted in S203), the process proceeds to step S204. If the refrigerator cold water outlet temperature is not to be changed (change is not permitted in S203), the process proceeds to step S206.

In step S204, the central controller 3 changes the value in its own memory so that the temperature determined in step S202 is output to the heat source controller 21 as a new setting value for the chiller cold water outlet temperature in step S106. do. The central controller 3 that executes the process of step S204 is an example of "instruction means".

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

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

When the central controller 3 could not acquire the room conditions, it determined the design information of the virtual air conditioner, and determined the virtual room design conditions based on the determined design information. The central controller 3 determines whether dehumidification of the outside air is necessary based on the virtual room design conditions and the outside air conditions obtained from the cooling tower controller 32 . When dehumidification of the outside air is unnecessary and when it is determined that the air conditioning load is small, the latent heat load in the room can be ignored. Optimize. That is, the central controller 3 can set the chiller cold water outlet temperature higher by the amount that the latent heat load is not processed. By setting the refrigerator cold water outlet temperature to a high value, the operating efficiency of the refrigerator 20 can be enhanced. As a result, even if the central controller 3 cannot acquire the indoor conditions, the COP of the entire air conditioning system 1 can be expected to be improved.

(If indoor conditions can be obtained)
FIG. 7 is a second diagram illustrating the inference flow of the chiller chilled water outlet temperature by the central controller 3 . FIG. 7 illustrates a processing flow for inferring the refrigerator cold water outlet temperature by the central controller 3 when the indoor conditions 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 indoor temperature and relative humidity from the air conditioner controller 14 . The central controller 3 determines whether or not to change the chiller cold water outlet temperature according to the amount of change between the currently acquired indoor temperature and relative humidity and the previously acquired indoor temperature and relative humidity. When the obtained indoor temperature or relative humidity tends to rise, the central controller 3 changes the memory set value of the refrigerator cold water outlet temperature output to the heat source controller 21 in step S106 so that the temperature of the cold water decreases. do. In addition, when the obtained indoor temperature or relative humidity tends to decrease, the central controller 3 sets the memory setting value of the chiller chilled water outlet temperature output to the heat source controller 21 in step S106 so that the chilled water temperature rises. to change Hereinafter, a processing flow for inferring the refrigerator cold water outlet temperature by the central controller 3 when the indoor conditions can be acquired will be described with reference to FIG. 7 .

n (n is an integer equal to or greater than 1) in FIG. 7 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 or not the air conditioner 10 for the n-th room is in operation. If the vehicle is driving (YES in S302), the process proceeds to step S303. If the vehicle is not running (NO in S302), the process returns 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, for example, by Equations 7-14 below.

In Equations 7 to 14, t _{RM_SP_LL} (n) is the allowable second lower limit of room temperature in the n-th room. t _{RM_SP} (n) is the set temperature set in the n-th room. t%(n) is the temperature tolerance applied in the nth room. t _{RM_SP_L} (n) is the allowable first lower limit of room temperature in the n-th room. tα is a correction value for the allowable range related to temperature, and in this embodiment, the initial value is 0.5. t _{RM_SP_H} (n) is the first allowable room temperature upper limit value in the n-th room. t _{RM_SP_HH} (n) is the second allowable room temperature upper limit value in the n-th room. φ _{RM_SP_LL} (n) is the allowable second lower limit of room humidity in the n-th room. φ _{RM_SP_L} (n) is the allowable first lower limit of room humidity in the n-th room. φ%(n) is the relative humidity tolerance applied to the nth room. φα is a correction value of the allowable range related to relative humidity, and its initial value is 0.5. φ _{RM_SP_H} (n) is the first allowable indoor humidity upper limit value in the n-th room. φ _{RM_SP_HH} (n) is the allowable second upper limit value of room humidity in the n-th room. The reason why the lower limit value and the upper limit value are set in two stages, the first and the second, is to suppress the amount of transient fluctuation in the indoor environment caused by the temperature change of the cold water, and to suppress the amount of heat generated in the room. This is to prevent the indoor environment from deviating from the control range due to changes in outdoor air conditions. The memory of the central controller 3 that stores the allowable range of room temperature and relative humidity set in step S303 is an example of the "storage means."

In step S<b>304 , the central controller 3 acquires the n-th indoor temperature t _{RM_PV} (n) and relative humidity φ _{RM_PV} (n) from the air conditioner controller 14 .

In step S305, the central controller 3 determines whether the temperature and relative humidity in the n-th room obtained in step S304 are within the allowable range for the set temperature. Step S305 in FIG. 7 illustrates an indoor air-conditioning state determination table used for this determination. In the indoor air-conditioning state determination table, a matrix is formed in which the horizontal axis represents the allowable temperature value determined in step S303 and the vertical axis represents the allowable relative humidity value. The central controller 3 can determine whether or not to change the refrigerator cold 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 region of t _{RM_PV} (n)>t _{RM_SP_HH} (n) and the region of φ _{RM_PV} (n)>φ _{RM_SP_HH} (n). Region of t _{RM_PV} (n) < t _{RM_SP_L} (n) and φ _{RM_PV} (n) < φ _{RM_SP_LL} (n), region of t _{RM_PV} (n) < t _{RM_SP_LL} (n) and φ _{RM_PV} (n) < φ _{RM_SP_L} (n) In the region, "1↑" is described. t _{RM_SP_H} (n)<t _{RM_PV} (n)<t _{RM_SP_HH} (n) and φ _{RM_PV} (
Described as "2↓" in the region of n)<φ _{RM_SP_H} (n), t _{RM_PV} (n)<t _{RM_SP_HH} (n) and φ _{RM_SP_H} (n)<φ _{RM_PV} (n)<φ _{RM_SP_HH} (n) It is Region 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 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. Also, in the region 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 of the n-th indoor temperature and relative humidity performed in step S305. In step S307, when the determination of all rooms to be air-conditioned by the air conditioning system 1 has been completed (YES in S307), the process proceeds to step S308. If the air-conditioning system 1 has not yet determined all the rooms to be air-conditioned (NO in S307), the process returns to step S301.

In steps S308 to S314, the central controller 3 determines whether or not to change the chiller cold water outlet temperature based on the determination results of the temperature and relative humidity in each room saved in the process of step S306.

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

In step S308A, the central controller 3 changes the memory set value 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 is lowered by 0.5°C. However, if the chilled water outlet temperature of the refrigerator falls below the lower limit value of the chilled water outlet temperature registered in the setting file when the temperature is lowered by 0.5°C, the central controller 3 changes the setting of the chilled water outlet temperature of the refrigerator to the lower limit value. . The process is then terminated.

In step S309, the central controller 3 determines whether or not there is a room that belongs to the area described as "2↓" in the indoor air-conditioning state determination table two times in a row in the determination results saved in step S306. judge. If there is a room belonging to the area described as "2↓" twice in succession (YES in S309), the process proceeds to S309A. If 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 memory set value 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 is lowered by 0.5°C. However, if the chilled water outlet temperature of the refrigerator falls below the lower limit value of the chilled water outlet temperature registered in the setting file when the temperature is lowered by 0.5°C, the central controller 3 changes the setting of the chilled water outlet temperature of the refrigerator to the lower limit value. . The process is then terminated.

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 saved in S306. If there is a room belonging to the area described as "2↓" (YES in S310), the process proceeds to step S310A. If 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. The process is then terminated.

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 saved in step S306. If there is a room belonging to the region marked "none" (YES in S311), the process proceeds to step S311A. If there is no room belonging to the area marked "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. The process is then terminated.

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 saved in step S306. If there is a room belonging to the area described as "1↑" (YES in S312), 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 memory set value 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, if the refrigerator cold water outlet temperature to be 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. The process is then terminated.

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

At step S313A, the central controller 3 does not change the refrigerator cold water outlet temperature. The process is then terminated.

In step S314, the central controller 3 confirms that all the rooms to be air-conditioned belong to the area indicated as "2↑" in the indoor air-conditioning state determination table two times in a row in the determination result saved in step S306. Determine whether or not. If all the rooms to be air-conditioned belong to the area described as "2↑" twice in a row (YES in S314), the process proceeds to step S314A. If there is a room that does not belong to the area described as "2↑" two times in a row (NO in S314), the process ends.

In step S314A, the central controller 3 changes the memory set value 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, if the refrigerator cold water outlet temperature to be 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. The process is then terminated. The central controller 3 that executes the processing from steps S308 to S314A is an example of the "determining means." Steps S308A, S309A, S310A, S311A, S312A, S313A and S314A
The central controller 3 that executes the process of 1 is an example of the "instruction means".

The central controller 3 determines whether or not to change the refrigerator cold water outlet temperature based on the indoor conditions acquired from the air conditioner controller 14 and the allowable range set in step S303 of FIG. Therefore, the central controller 3 can optimize the chiller cold water outlet temperature in a more realistic manner than when performing control based on the virtual room design conditions, and an improvement in the 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 the 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 conditions for each assumed approach temperature, and determines the cooling water temperature that minimizes the energy consumption. The central controller 3 changes the memory set value of the cooling water temperature output to the cooling tower controller 32 in step S106 so that the cooling water temperature is controlled at 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 amount of calculation. If the cooling water temperature is optimized, the operating efficiency of the cooling tower 30 will increase, and an improvement in the COP of the air conditioning system 1 as a whole can be expected.

8 to 10 are diagrams for explaining inference of the cooling water temperature based on the approach temperature. FIG. 8 is a diagram illustrating the items used to infer the cooling tower and cooling water temperature. Let the cooling tower approach temperature T _AP (°C) be the parameter for inferring the cooling tower cooling water temperature. Input items are outside air wet-bulb temperature T _WB (°C), cooling tower heat release q _CT (kW), and 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 optimization, the cooling water flow rate Q _CD is controlled in the range of 50-100%. Also, the cooling tower fan air volume G is controlled within a range of 20 to 100%. The central controller 3 calculates the 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 evaluates the heat source system (air conditioning system 1 ) is evaluated. The cooling water temperature T _CDS (°C) when the energy consumption of the air conditioning system 1 is the minimum, that is, when the COP of the air conditioning system 1 is maximum, is output as an output item.

FIG. 9 is a graph illustrating a range of coolant temperatures based on ambient wet bulb temperature and approach temperature. In the graph of FIG. 9, the vertical axis is the cooling water temperature, and the horizontal axis is the outside air wet-bulb temperature. The approach temperature is assumed in the range of 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 outside air wet-bulb temperature plus the approach temperature of 2°C to 5°C. When the outside air wet-bulb temperature varies in the range of 10° C. to 27° C., the cooling water temperature is set 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 determined. For example, when the outside air wet bulb temperature is 16°C, the control target value for 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 steps of 0.5°C, the control target values for the cooling water temperature are 18°C, 18.5°C, ..., 21°C in steps of 0.5°C. is the value of The central controller 3 calculates the energy consumption of the air conditioning system 1 for each control target value, and determines the control target value that minimizes the calculated energy consumption as the cooling water temperature to be set.

FIG. 10 is a flowchart illustrating the flow of inference processing for the cooling water temperature. FIG. 10 is a diagram showing an example of details of the process of S104. Inference processing of the cooling water temperature is performed by the central controller 3 at predetermined intervals, for example, 10 minute intervals. Further, the inference processing 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 outdoor air wet-bulb temperature from the measured outdoor air dry-bulb temperature and outdoor air relative humidity. The outside air wet-bulb temperature can be calculated from the saturated water vapor pressure, water vapor partial pressure, absolute temperature, and enthalpy obtained from the outside air dry-bulb temperature and the outside air relative humidity.

At step S402, the central controller 3 assumes the approach temperature, which is a parameter for inferring the cooling water temperature of the cooling tower 30. Approach temperatures are assumed, for example, within a 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 a control target value from the outside air wet-bulb temperature calculated in step S401 and the approach temperature assumed in step S402.

Steps S<b>404 to S<b>407 are processing for calculating the power of the cooling water circulation pump 51 of the refrigerator 20 . In step S<b>404 , the central controller 3 calculates the heat dissipation amount of the entire system (hereinafter simply referred to as “heat dissipation amount”) to be dissipated by the cooling tower 30 from the operating load factor of each refrigerator 20 in operation.

At step S405, the central controller 3 obtains the temperature difference between the inlet and outlet of the cooling water of the refrigerator 20 from the amount of heat dissipation calculated at step S404. The cooling water inlet/outlet temperature difference varies depending on the cooling water flow rate. When the cooling water flow rate decreases, the residence time of the cooling water staying in the condenser of the refrigerator 20 increases, so the cooling water inlet/outlet temperature difference of the refrigerator 20 increases. . Therefore, the central controller 3 calculates the cooling water inlet/outlet temperature difference, which affects the calculation of the cooling water flow rate, from the amount of heat dissipation calculated in step S404, taking into account the effect on the COP due to the increase or decrease in 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 release calculated in step S404 and the cooling water inlet/outlet temperature difference calculated in step S405.

At 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 at step S406.

Steps S<b>408 to S<b>411 are processing 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 obtained in step S405.

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

In step S411, the central controller 3 calculates the air volume of the cooling tower fan 31 from the heat release 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 or not the air volume G of the cooling tower fan 31 calculated in step S411 is equal to or less than the rated air volume _G0 of the cooling tower 30 or not. The rated air volume G ₀ is an air volume calculated based on the flow rate of cooling water, the amount of heat radiation, and the like. 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 equal to or less than the rated air volume _G0 . On the other hand, if the air volume G of the cooling tower fan 31 is greater than the rated air volume G ₀ , the central controller 3 returns to step S402, assumes the next approach temperature, and repeats the processes from step S403. The central controller 3 can suppress the amount of calculation by not executing the arithmetic processing when the air volume G of the cooling tower fan 31 is greater than the rated air volume 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 determines the power of the cooling water circulation pump 51 calculated in step S407, the power of the cooling tower fan 31 calculated in step S413, the power consumption of the refrigerator 20, and the power consumption of the refrigerator 20 for circulating cold water. is calculated as the power consumption of the air conditioning system 1 . For each approach temperature assumed in step S402, the central controller 3 repeats the process of calculating the power consumption of the air conditioning system 1 only under the condition that satisfies step S412, 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 this time, the central controller 3 uses the chilled water temperature estimated in step S103 to select the approach temperature that minimizes the power consumption of the air conditioning system 1 at the estimated chilled water temperature. Then, the central controller 3 obtains the cooling water temperature by adding the approach temperature to the outside air wet-bulb temperature, and determines this value as the control value. The central controller 3 changes the memory set value of the cooling water temperature output to the cooling tower controller 32 in step S106 so that the cooling water temperature is controlled at the determined cooling water temperature. As a result, the approach temperature is selected for the estimated chilled water temperature, so the amount of calculation is suppressed compared to the case where the calculation process is performed regardless of whether the chilled water temperature is within the range that can be cooled by the cooling tower. be. The cooling tower controller 32 performs control so that the cooling water temperature, which reduces the energy consumption of the entire air conditioning system, reaches 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 taken.

<Step S105>
In step S105, the central controller 3 infers the number of chillers 20 in operation. The central controller 3 infers the number of operating chillers 20 based on the operation design sheet prepared in advance. The operation design sheet includes operation information specifying the number of operating refrigerators 20 that minimizes the energy consumption of the air conditioning system 1 for each operating condition (refrigerator cold water outlet temperature and cooling tower cooling water outlet temperature). It is created in advance based on the performance data of the refrigerator 20 and the characteristic data of each device such as a pump and a fan according to the operating conditions. The characteristic data is, for example, data indicating the 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 machine". Also, the operation design sheet is an example of "operation information".

Based on the refrigerator cold water outlet temperature and the cooling water temperature inferred in steps S103 and S104, the central controller 3 selects the refrigerator 20 that minimizes the energy consumption of the air conditioning system 1 from an operation design sheet created in advance. Get the operating number of The central controller 3 changes the memory setting value of the number of operating refrigerators 20 output to the heat source controller 21 in step S106 so that the obtained number of operating refrigerators 20 is used for control.

In the inference of step S105, the central controller 3 optimizes the number of chillers 20 in operation by acquiring operational information according to operational conditions from an operational design sheet prepared in advance. If the number of operating refrigerators 20 is optimized, the operating efficiency of the refrigerators 20 will increase, and an improvement in the COP of the entire air conditioning system 1 can be expected.

The operational design sheet referred to by the central controller 3 in step S105 is created, for example, as follows. 11 to 17 are diagrams for explaining the creation of an operation design sheet for inferring the number of operating chillers 20. FIG. FIG. 11 is a diagram illustrating calculation of power consumption of a refrigerator for each operating condition. A partial load characteristic diagram (hereinafter also referred to as performance data) corresponding to the type and capacity of the refrigerator 20 (heat source) is provided by the manufacturer of the refrigerator 20 or by actual measurement. The performance data is a graph showing changes in the COP of the single refrigerator 20 with respect to the load factor of the single refrigerator 20 for each refrigerator 20, cold water temperature, and cooling water temperature. The performance data of the type of refrigerator 20 for which the performance data is not provided in advance can be complemented based on the performance data prepared in advance as the reference data. Also, performance data for chilled water temperature and cooling water temperature for which performance data is not given in advance can be interpolated based on performance data for temperatures before and after. By supplementing or interpolating the missing performance data for the existing performance data, for each refrigerator 20, for example, performance data for cooling water temperature in increments of 1°C and cold water temperature in increments of 0.5°C can be obtained. be prepared. The central controller 3 or other 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 specify the number of refrigerators 20 in operation.

FIG. 12 is a diagram illustrating calculation of the power consumption of the auxiliary machine for each load factor of the refrigerator. For auxiliary equipment such as various pumps and various fans provided in the cooling tower 30 and the refrigerator 20, each auxiliary equipment is controlled for each load factor of the refrigerator 20 based on the control method 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 identify the number of refrigerators 20 in operation.

FIG. 13 is a diagram illustrating complementation of performance characteristic data. Hereinafter, the performance characteristic data will also simply be referred to as performance data. When creating the operation design sheet, performance data for each operating condition of the reference refrigerator 20 is registered in advance as reference data in a computer used for creating 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 under the same operating conditions to grasp the difference. The computer supplements the performance data of the refrigerator 20 to be evaluated under the operating conditions based on the grasped difference from the reference data under the operating conditions for which there is no performance data for the refrigerator 20 to be evaluated. By complementing the performance data, the computer can infer the power consumption of the refrigerators 20 for each operating condition, and specify the number of operating refrigerators 20 that minimizes the energy consumption of the air conditioning system 1 .

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

FIG. 14 shows, in tabular form, an example of a combination of operational priorities for the three refrigerators 20 (heat source 1, heat source 2, and 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 identifying the operation design sheet. This is an operation design sheet for a certain case. The central controller 3 monitors the order of operation priority of the refrigerators 20, and when there is a change in the order of priority due to rotation or maintenance of the refrigerators 20, the corresponding operation design sheet is referred to and the order of operation of the refrigerators 20 is changed. 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 number of units in operation according to the heat source (chiller 20) load factor is specified for each cooling water temperature. Specifically, when the cold water temperature is 7° C. and the cooling water temperature is 24° C., the number of operating refrigerators 20 that minimizes the energy consumption of the air conditioning system 1 is 2 at a heat source load factor of 33% or more. 55% or more is 3 units. By defining the number of chillers 20 in operation that maximizes the COP of the entire air conditioning system 1 in this manner 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 control of the number of operating refrigerators 20 based on information on cold water temperature and cooling water temperature obtained from the heat source controller 21 or the like.

FIG. 16 is a graph illustrating an increase in the number of operating heat sources. The vertical axis is the number of operating heat sources, and the horizontal axis is the heat source load factor. FIG. 16 is a graph showing an example in the case of the cooling water temperature of 7° C. and the cooling water temperature of 24° C. shown in FIG. Also, the order of priority for operation of the heat sources is heat source 1, heat source 2, and heat source 3, and the number of heat sources in operation is controlled based on the corresponding operation design sheet. P1 indicated on the horizontal axis is the threshold of the heat source load factor when increasing the number of operating heat sources from one to two. In the example of FIG. 16, P1 is 33%, and when the heat source load factor becomes 33% or more, the number of operating units is increased from 1 to 2 units, and when the heat source load factor becomes lower than 33%, the number of operating units increases from 2 units. Reduced to 1 unit. Similarly, P2 indicated on the horizontal axis is the threshold of the heat source load factor when increasing the number of operating heat sources from two to three. In the example of FIG. 16, P2 is 55%, and when the heat source load factor becomes 55% or more, the number of operating units is increased from 2 to 3 units, and when the heat source load factor becomes lower than 55%, the number of operating units increases from 3 units Reduced to 2 units. The thresholds P1 and P2 for the heat source load factor that controls the number of units in operation (hereinafter also referred to as step-up/down points) are based on the measurement data of the heat source load factor and the conditions such as whether the heat source load factor is on an upward trend or a downward trend. identified.

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 is the COP of the heat source system, and the horizontal axis is the load factor of the entire heat source. The facilities assumed in the creation of the graph in FIG. 17 are all inverter type, and consist of two centrifugal chillers, two cold water pumps, two cooling water pumps, and two integrated cooling towers. Also, the cold water temperature is assumed to be 7°C. The values indicated by the arrows in the figure indicate the step-up/down points of the heat source. As can be seen from the graph of FIG. 17, as the cooling water temperature decreases, the step increase/decrease point shifts to the low load factor side. This is because the maximum efficiency point of the performance diagram of the single heat source shifts to the low load factor side as the cooling water temperature decreases. Therefore, in the operation design sheet used for the central controller 3, as shown in the graph of FIG. 17, the heat source step-up/down points are set at slightly different positions for each cooling water temperature.

FIG. 18 is a flowchart illustrating processing for creating an operation design sheet. The computer used to create the operation design sheet performs the following processing before the air conditioning system 1 starts operating 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 computer or the auxiliary storage device of 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 auxiliary machines such as refrigerators 20, cooling towers 30, various pumps, and various fans that constitute the air conditioning system 1. FIG.

In step S502, the computer repeats the processing from steps S503 to S507 for each temperature interval of 0.5°C, for example, within the range of 5°C to 12°C for the chilled water temperature (chilled water outlet temperature of the refrigerator). That is, an operation design sheet is created for each chilled water temperature in increments of 0.5°C. The operational design sheet is not limited to being created for each cold water temperature of 0.5°C. By creating an operation design sheet with narrower temperature intervals, the accuracy of inference of the number of operating heat sources (refrigerators 20) is improved. Further, the computer may create an operation design sheet not only for each cold water temperature at equal intervals, but also for each cold water temperature set in advance. 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 for each temperature interval of 1°C, for example, within the range of the cooling water temperature (cooling tower cooling water outlet temperature) from 12°C to 34°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 intervals of 1°C. The inference of the number of heat sources in operation is not limited to every 1° C. of cooling water temperature, and may be inferred for each preset cooling water temperature. As can be seen from FIG. 17, with the heat source alone, the maximum 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. Considering the deviation, the cooling water temperature can be set to infer the number of heat sources in operation.

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%, for example, within the heat source load factor range of 20% to 100%. Repeat process. The calculation of the number of operating heat sources is not limited to 10% intervals, and 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 intervals of 1%, for example. good too.

In step S505, the computer determines the chilled water temperature (5° C. to 12° C.) set in step S502, the cooling water temperature (12° C. to 34° C.) set in step S503, and the total heat source load set in step S504. Based on the rate (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 combination conditions of these values. Specifically, first, referring to the device information (characteristic data as shown in FIGS. 11 and 12) read in step S501, the values of the set chilled water temperature, cooling water temperature, and heat source overall load factor are The corresponding COP value of the refrigerator alone and the power consumption values of the pump and fan are read. The power consumption of the refrigerator is calculated based on the COP of the refrigerator alone and the heat source load factor. Then, the power consumption value of the refrigerator alone and the total power consumption value of the pump and the fan are calculated as the energy consumption. The computer performs the above-described calculation processing for all combinations of chilled water temperature, cooling water temperature, and heat source overall load factor. Then, the computer stores the energy consumption calculated for each combination condition in the auxiliary storage device as the calculation result for the combination condition. Next, when there are two or more heat sources, the power consumption value of each heat source is calculated based on the value obtained by dividing the total heat source load factor by the number of heat sources. The power consumption values of the plurality of heat sources are added to the power consumption values of the pump and the fan to obtain the energy consumption amount. When the heat sources have different performances, the power consumption of each 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 when there are two or more heat sources as described above for all combination patterns of a plurality of heat sources (one heat source or two or more heat sources) Calculate consumption. Then, for all combination conditions of chilled water temperature, cooling water temperature, and heat source overall load factor, the energy consumption amounts in all combination patterns of a plurality of heat sources are compared with each other, and the heat source operation when the energy consumption amount is the minimum. The number of units is selected as the number of operating heat sources under the combined condition of cold water temperature, cooling water temperature, and heat source overall load factor, and this number of operating units is stored in the auxiliary storage device. In this way, the number of operating heat sources corresponding to the cooling water temperature and the overall heat source load factor is determined for each cold water temperature, and the determined number of operating heat sources is stored in a table, that is, an operation design sheet as shown in FIG. . The power consumption values are obtained on the assumption that the power of the cooling water circulation pump 51, the cooling tower fan 31, and the load factor of the cold water primary pump 41 are the same as the overall heat source load factor of the refrigerator 20. FIG.

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

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

In step S509, the computer completes the operation design sheet for the air conditioning system 1 for each pattern of heat source operation priority. Specifically, based on the information on the number of operating heat sources calculated in step S505, the computer specifically identifies a step point for controlling the number of operating heat sources based on the measured value of the heat source load factor, and creates an operation design sheet. Finalize. In this way, the number of operating refrigerators 20, which are heat sources, can be obtained based on information about the devices that make up the air conditioning system 1, even if the outside air conditions, which are environmental variables, are not given. It can be pre-calculated and stored before starting.

When I roughly estimated the amount of reduction in power consumption, it depends on the equipment configuration and various conditions of the entire system, but the adjustment of the set value of the chiller cold water outlet temperature performed by the central controller 3 as described above, and the number of chillers 20 in operation A trial calculation result was obtained that the power consumption can be reduced by more than 10% compared to 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 rate adjustment valve: 14 Air conditioner controller: 20 Refrigerator: 21 Heat source controller: 30 Cooling tower: 31 Cooling tower fan: 32 Cooling tower controller: 40 Chilled water circulation system: 41 Chilled water 1 Secondary pump: 42... Cold water secondary pump: 43... Minimum flow valve: 44... Secondary pump controller: 50... Cooling water circulation system: 51... Cooling water circulation pump

The central controller 3, which has completed the design of the virtual air conditioner and the virtual room design condition assumption processing through the above processing, performs the dehumidification determination in step S201. In this determination, the central controller 3 compares the absolute humidity of the outside air obtained from the heat source controller 21 of the cooling tower 30 with the indoor absolute humidity under the virtual room design conditions. First, the central controller 3 refers to the psychrometric diagram of FIG. 5 and calculates the indoor absolute humidity from the indoor temperature and humidity measured value. The central controller 3 compares the calculated absolute humidity of the indoor air and the absolute humidity of the outdoor 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 required (dehumidification is not required in S201), and the process proceeds to step S202. When the absolute humidity of the indoor air is lower 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. The central controller 3 that calculates the absolute humidity of the outside air is an example of the "first calculation means". The central controller 3 that calculates the indoor absolute humidity under the virtual indoor design conditions is an example of the "second calculating means."

Claims (6)

storage means for storing information used for calculation of indoor conditions including the temperature and relative humidity of the air supplied to the room by the air conditioner assumed based on the design information of the heat source equipment;
When the outside air conditions including the acquired outside air temperature and relative humidity and the indoor conditions calculated based on the information satisfy a predetermined condition that dehumidification of the outside air is unnecessary, the heat source device supplies the air conditioner with the a first determining means for determining the temperature of the cold water to be a temperature that enables supply of air capable of processing sensible heat in the room;
an instruction means for instructing the controller of the heat source equipment to set the temperature of the cold water to the determined temperature;
Air conditioning system controller. a first calculation means for calculating the absolute humidity of the outside air based on the temperature and relative humidity of the outside air;
a second calculation means for calculating the absolute humidity in the room based on the temperature and relative humidity of the supplied air;
The case where the predetermined condition is satisfied is the case where the absolute humidity in the room is higher than the absolute humidity in the outside air.
The control device for an air conditioning system according to claim 1. further comprising a second determining means for determining an upper limit temperature of cold water supplied to the air conditioner by the heat source device based on the temperature of the outside air and the cooling performance of the heat source device;
When the temperature of the cold water determined by the first determination means is higher than the upper limit temperature, the instruction means instructs the temperature of the cold water to be the determined upper limit temperature.
The air conditioning system control device according to claim 1 or 2. the computer
storing information used to calculate indoor conditions including the temperature and relative humidity of the air supplied to the room by the air conditioner assumed based on the design information of the heat source equipment;
When the outside air conditions including the acquired outside air temperature and relative humidity and the indoor conditions calculated based on the information satisfy a predetermined condition that dehumidification of the outside air is unnecessary, the heat source device supplies the air conditioner with the Determine the temperature of the cold water in the room to a temperature that enables air supply that can process the sensible heat in the room,
instructing the controller of the heat source machine to set the temperature of the cold water to the determined temperature;
How to control the air conditioning system. to the computer,
storing information used for calculating indoor conditions including the temperature and relative humidity of the air supplied to the room by the air conditioner assumed based on the design information of the heat source equipment;
When the outside air conditions including the acquired outside air temperature and relative humidity and the indoor conditions calculated based on the information satisfy a predetermined condition that dehumidification of the outside air is unnecessary, the heat source device supplies the air conditioner with the determining the temperature of the cold water in the room to a temperature that enables air supply that can process the sensible heat in the room;
instructing the controller of the heat source machine to set the temperature of the cold water to the determined temperature;
Control program for air conditioning system. an air conditioner that conditions the air in the room; and
a heat source device that supplies cold water to the air conditioner, and the temperature of the supplied cold water is controlled by a controller;
a controller;
The control device is
storage means for storing information used for calculating indoor conditions including the temperature and relative humidity of the air supplied to the room by the air conditioner assumed based on the design information of the heat source equipment;
When the outside air conditions including the acquired outside air temperature and relative humidity and the indoor conditions calculated based on the information satisfy a predetermined condition that dehumidification of the outside air is unnecessary, the heat source device supplies the air conditioner with the a first determining means for determining the temperature of the cold water to be a temperature that enables supply of air capable of processing sensible heat in the room;
an instruction means for instructing the controller of the heat source equipment to set the temperature of the cold water to the determined temperature;
air conditioning system.

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