EP4592609A1

EP4592609A1 - Heat source system, air conditioning system, control method, and control program

Info

Publication number: EP4592609A1
Application number: EP22959500.4A
Authority: EP
Inventors: Satoru Saegusa; Tetsuji Fujino
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2022-09-20
Filing date: 2022-09-20
Publication date: 2025-07-30
Also published as: EP4592609A4; WO2024062536A1; JPWO2024062536A1

Abstract

This heat source system (3) supplies a heat medium to a use-side unit (2) and comprises: a plurality of heat source machines (5); and a controller (8) that controls the number of operating heat source machines (5) and the target capacity assigned to each heat source machine (5) in accordance with a required capacity required by the use-side unit (2). The controller (8) holds a maximum operating capacity and an appropriate operating capacity for each heat source machine (5), and when the target capacity assigned to a first heat source machine (5a) among the operating heat source machines (5) reaches the maximum operating capacity, the controller (8) starts a stopped second heat source (5b) and sets the target capacity of the first heat source machine (5a) to the appropriate operating capacity thereof.

Description

Technical Field

The present disclosure relates to a heat source system, an air-conditioning system, a control method, and a control program.

Background Art

In the related art, an air-conditioning system is known, which includes a heat source system having a plurality of heat source machines and a usage-side unit that performs air conditioning by using a heat medium supplied from the heat source system. In such an air-conditioning system, it is known that an operating capacity is determined based on a frequency of a voltage applied to a compressor. In addition, it is known that a partial load operation in which an operation is performed at an operating capacity lower than a maximum load operation in which the operating capacity is 100% is more efficient than the maximum load operation.
PTL 1 discloses that an operating capacity is determined to determine whether or not a partial load operation is performed, and the partial load operation is performed when the operating capacity is equal to or less than a predetermined value.

Citation List

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2011-112333

Summary of Invention

Technical Problem

Meanwhile, in the invention of PTL 1, the partial load operation is performed in a case where the operating capacity is not 100%, and control in a case where the operating capacity is 100% or exceeds 100% has not been studied.
The present disclosure has been made in view of such circumstances, and an object thereof is to provide a heat source system, an air-conditioning system, a control method, and a control program that avoid driving a heat source machine at 100%, which is a maximum operation capacity.

Solution to Problem

In order to achieve the above-described object, a heat source system, an air-conditioning system, a control method, and a control program of the present disclosure employ the following means.
A heat source system of the present disclosure is a heat source system that supplies a heat medium to a usage-side unit, the heat source system including: a plurality of heat source machines; and a controller that controls the number of the plurality of heat source machines in operation and a target capacity allocated to each of the heat source machines according to a required capacity required by the usage-side unit, in which the controller holds a maximum operation capacity and an appropriate operation capacity of each of the heat source machines, and activates a second heat source machine that is stopped and sets the target capacity of a first heat source machine among the heat source machines being operated to the appropriate operation capacity in a case where the target capacity allocated to the first heat source machine reaches the maximum operation capacity.
An air-conditioning system of the present disclosure includes the heat source system, and an air handling unit to which a heat medium is supplied from the heat source system.
A control method of the present disclosure is a control method for a heat source system including a plurality of heat source machines and supplying a heat medium to a usage-side unit, the method being executed by a computer and including: holding a maximum operation capacity and an appropriate operation capacity of each of the heat source machines; and activating a second heat source machine that is stopped and setting a target capacity of a first heat source machine among the heat source machines being operated to the appropriate operation capacity in a case where the target capacity allocated to the first heat source machine reaches the maximum operation capacity.
A control program of the present disclosure causes a computer to function as the controller.

Advantageous Effects of Invention

According to the heat source system of the present disclosure, it is possible to avoid an operation at the maximum operation capacity, increase efficiency of a compressor of the heat source machine by driving the compressor at a partial load, and extend an operating life.

Brief Description of Drawings

Fig. 1 is a diagram showing an overall schematic configuration of an air-conditioning system according to an embodiment of the present disclosure.
Fig. 2 is a diagram showing a schematic configuration of a heat source system according to an embodiment of the present disclosure.
Fig. 3 is a diagram showing a configuration example of a refrigerant circuit of the heat source machine according to an embodiment of the present disclosure.
Fig. 4 is a diagram schematically showing an overall configuration of a control system for controlling the air-conditioning system according to an embodiment of the present disclosure.
Fig. 5 is a diagram showing an example of a hardware configuration of a heat source machine controller according to an embodiment of the present disclosure.
Fig. 6 is a functional block diagram showing an example of a function included in the heat source machine controller according to an embodiment of the present disclosure.
Fig. 7 is a flowchart showing an example of the processing procedure of a control method for the heat source system executed by the heat source machine controller according to an embodiment of the present disclosure.
Fig. 8 is a diagram showing a target capacity for a required capacity of an entire system according to an embodiment of the present disclosure.
Fig. 9 is a diagram showing the target capacity for the required capacity of the entire system according to an embodiment of the present disclosure.
Fig. 10 is a diagram showing the target capacity for the required capacity of the entire system according to an embodiment of the present disclosure.

Description of Embodiments

(Configuration of Air-Conditioning System)

Hereinafter, an embodiment of a heat source system, a control method therefor, and a program according to the present disclosure will be described with reference to the drawings.
Fig. 1 is a diagram showing an overall schematic configuration of an air-conditioning system according to an embodiment of the present disclosure. As shown in Fig. 1, an air-conditioning system 1 includes a direct expansion type air handling unit (hereinafter, referred to as an "AHU") 2 and a heat source system 3. In the present embodiment, the AHU 2 is described as an example of the usage-side unit, but the present disclosure is not limited thereto. The usage-side unit may be another type of air handling unit such as a cold/hot water type air handling unit. In addition, the usage-side unit is not limited to the air handling unit, and may be a system that performs air conditioning using a heat medium supplied from the heat source system.
The AHU 2 performs air conditioning and ventilation of a space to be air-conditioned (for example, a room R in Fig. 1) in various buildings such as an office, a commercial building, a hospital, and a factory. As shown in Fig. 1, the AHU 2 includes, for example, a total heat exchanger (not shown), a heat exchanger 21 (21a, 21b, and 21c), a temperature sensor 22 (22a, 22b, and 22c), a fan 23, and a temperature sensor 24. The heat exchanger 21 (21a, 21b, and 21c), the temperature sensor 22 (22a, 22b, and 22c), the fan 23, and the temperature sensor 24 are disposed, for example, inside a housing 7.
The total heat exchanger exchanges heat between the air taken in from the outside and the air taken in from the room R. The air heat exchanged with the air from the room R in the total heat exchanger is sent to the heat exchanger 21. The heat exchanger 21 exchanges heat between the air and the heat medium (the refrigerant in the present embodiment) supplied from the heat source system 3. The air cooled or heated by exchanging heat with the heat medium is sucked into the fan 23. The fan 23 sends out the sucked air. The air sent out from the fan 23 is sent to the room R which is a space to be air-conditioned after passing through a pipe.
The temperature sensor 22 is provided in the heat exchanger 21. The installation position of the temperature sensor 22 is not limited to this example, and may be a position where the temperature of the air after heat exchange in the heat exchanger 21 can be measured.
A system controller 10 (AHU controller) calculates a required capacity based on a difference between the set temperature set by the remote controller (not shown) and the temperature measured by the temperature sensor 24, and outputs the required capacity to the heat source system 3. For example, the system controller 10 calculates the required capacity by performing feedback control based on the difference between the set temperature and the measured temperature. The calculation of the required capacity is known, and various known techniques may be appropriately adopted.
In addition, the system controller 10 controls the rotation speeds of the fan 23. The control by the system controller 10 may adopt a known technique, and a detailed description thereof will be omitted.
The heat source system 3 includes a heat source machine controller 8 (8a, 8b, and 8c), and for example, the heat source machine controller (controller) 8a is set as a master machine. The heat source machine controller 8a controls the operating condition and output capacity of each heat source machine 5 (5a, 5b, and 5c) via each heat source machine controller 8.
The heat source machine controller 8 may control the operating condition and output capacity of each heat source machine 5 based on the information input by a remote controller 29.
The heat source system 3 includes a plurality of heat source machines 5 (refer to Fig. 2), and supplies the heat medium to the AHU 2.
Fig. 2 is a diagram showing a schematic configuration of the heat source system 3. As shown in Fig. 2, the heat source system 3 includes a plurality of heat source machines (outdoor units) 5a, 5b, and 5c. For example, the heat exchanger 21 included in the AHU 2 has a configuration in which a plurality of heat exchangers 21a, 21b, and 21c are integrated. In the present embodiment, the heat source machine 5a is configured to individually supply the heat medium to the heat exchanger 21a, the heat source machine 5b is configured to individually supply the heat medium to the heat exchanger 21b, and the heat source machine 5c is configured to individually supply the heat medium to the heat exchanger 21c. The correspondence relationship between the heat source machine 5 and the heat exchanger 21 is not limited to this example, and a known refrigerant connection form can be appropriately adopted.
In addition, in the following, when it is necessary to distinguish the heat source machines 5a and 5b from each other, the heat source machines 5a and 5b are referred to as the heat source machines 5a and 5b, and when it is not necessary to distinguish the heat source machines 5a and 5b, the heat source machines 5a and 5b are simply referred to as the heat source machine 5. In addition, the same applies to other configurations.
Fig. 3 is a diagram showing a configuration example of a refrigerant circuit of the heat source machine 5a. The refrigerant circuit of the heat source machine 5b and the refrigerant circuit of the heat source machine 5c also have the same configuration.
As shown in Fig. 3, the heat source machine 5a is a heat source machine of a heat pump type, and includes a compressor 11 that compresses the refrigerant. The compressor 11 is, for example, a compressor having a variable rotation speed driven by an inverter motor (not shown). For example, the output of the heat source machine 5a is controlled by controlling the frequency (rotation speed) of the inverter motor of the compressor 11 by the heat source machine controller 8a (to be described later). The compressor 11 is not limited to this example, and may be, for example, a fixed speed compressor in which the rotation speed is fixed.
In addition, the heat source machine 5a includes a heat exchanger 13 that exchanges heat between the refrigerant and the outside air, the fan 14, an electron expansion valve 16 that expands the refrigerant, and the like. In addition, the heat source machine 5a may include a switching valve (for example, a four-way switching valve) 12 that switches a circulation direction of the refrigerant. By providing the switching valve 12, it is possible to correspond to both the cooling and the heating. In addition, the heat source machine 5a may include an accumulator 15 provided in a suction-side pipe of the compressor 11 for the purpose of gas-liquid separation of the refrigerant.
The heat exchanger 21a included in the AHU 2 shares the heat source machine 5a and a refrigerant pipe, and is configured to directly supply the refrigerant from the heat source machine 5a.
As an example of the refrigerant circulating through the refrigerant pipe, a low global-warming potential (GWP) mildly flammable refrigerant can be given. For example, the general alternative refrigerant in the HFC refrigerant regulation for preventing global warming (for example, R1234yf [4], R1234ze(E) [4], R1233zd(E) [5], R32 [675], and the like, the numerals in the square brackets [ ] indicate the GWP (100-year value)) and the refrigerant having the same or equivalent GWP (100-year value) are given. The type of the refrigerant is not particularly limited, and other refrigerants such as a brine, or water may be used.
Since the operation of the heat source machine of the heat pump type is known, a detailed description thereof will be omitted.
Fig. 4 is a diagram schematically showing an overall configuration of a control system that controls the air-conditioning system according to the present embodiment. As shown in Fig. 4, the air-conditioning system 1 includes the system controller 10, and the heat source machine controller 8 (8a, 8b, and 8c).
The system controller 10 and the heat source machine controller 8 (8a, 8b, and 8c) are connected to each other via a communication line and are configured to be capable of bidirectional communication.
Among the heat source machine controllers 8, the heat source machine controller 8a which is the master machine controls the heat source system 3. For example, the heat source machine controller 8a performs the number control for controlling the number of the plurality of heat source machines 5 in operation according to the required capacity required by the AHU 2 and/or the input information of the remote controller 29.
In addition, the heat source machine controller 8a may perform capacity allocation control for allocating an output capacity to the heat source machine 5. The heat source machine controller 8a transmits, for example, an activation command, a stop command, and a target capacity command to each heat source machine controller 8.
Each heat source machine controller 8 controls the driving of the compressor 11 (refer to Fig. 3) and the like based on the required capacity required by the AHU 2 received from the system controller 10. In addition, the rotation speed of the compressor 11 is controlled based on the capacity command. For example, the heat source machine controller 8 has an arithmetic expression or a table for converting the capacity command into a frequency command of the compressor 11, and controls the rotation speed of the compressor 11 corresponding to the capacity command by using these pieces of information. Since various control methods for the capacity control (output control) of the compressor 11 have been proposed, it is possible to appropriately adopt the known method.
Fig. 5 is a diagram showing an example of a hardware configuration of the heat source machine controller 8. As shown in Fig. 5, the heat source machine controller 8 includes, for example, a central processing unit (CPU) (processor) 31, a main memory 32, a secondary storage (memory) 33, and a communication interface 34. The respective units are directly or indirectly connected to each other via a bus, and cooperate with each other to execute various processing.
The CPU 31 performs control of the entire heat source system by an operating system (OS) stored in the secondary storage 33 connected via a bus, for example, and performs various processing by executing various programs stored in the secondary storage 33. One or a plurality of the CPUs 31 may be provided to cooperate with each other to realize the processing.
For example, the main memory 32 includes a writable memory such as a cache memory or a random-access memory (RAM), and is used as a work region for reading an execution program of the CPU 31 and writing processing data of the execution program.
The secondary storage 33 is a non-transitory computer readable storage medium. The secondary storage 33 is, for example, a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Examples of the secondary storage 33 include a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), and a flash memory. The secondary storage 33 stores, for example, an OS for controlling the entire heat source system such as Windows (registered trademark), iOS (registered trademark), and Android (registered trademark), a basic input/output system (BIOS), various device drivers for operating the hardware of the peripheral devices, various application software, various data and files, and the like. In addition, the secondary storage 33 stores a program for realizing various processing and various data required to realize various processing. A plurality of the secondary storages 33 may be provided, and the program and the data as described above may be divided and stored in each of the secondary storages 33. In addition, the secondary storage 33 may be provided on a cloud, and some of the programs or data stored in the secondary storage 33 may be provided on a cloud.
The communication interface 34 functions as an interface for performing communication with another device via a communication line and transmitting and receiving information. For example, the communication interface 34 communicates with the other devices in a wired or wireless manner. Examples of the wireless communication include communication through a line such as Bluetooth (registered trademark), Wi-Fi, a mobile communication system (3G, 4G, 5G, 6G, LTE, or the like), and a wireless LAN. Examples of the wired communication include communication through a line such as a wired local area network (LAN).
The heat source machine controller 8 is also a computer and has the same configuration as the heat source machine controller 8a described above.
Fig. 6 is a functional block diagram showing an example of a function included in the heat source machine controller. As shown in Fig. 6, the heat source machine controller 8a includes a target capacity control unit 41 and a target capacity calculation unit 42.
The target capacity control unit 41 controls the operation capacity of the heat source machine 5 based on the required capacity required by the AHU 2. The heat source machine 5 has a maximum operation capacity, an appropriate operation capacity, and a minimum operation capacity.
In a case where the operation of the plurality of heat source machines 5 is required for the required capacity, the target capacity control unit 41 controls each of the heat source machines 5 according to each target capacity calculated by the target capacity calculation unit 42 to be described later.
The target capacity calculation unit 42 calculates the target capacity of the heat source machine 5 with respect to the required capacity required by the AHU 2. In a case where one machine can respond to the required capacity, the target capacity calculation unit 42 calculates a target capacity corresponding to the required capacity. In a case where it is necessary to respond to the required capacity with a plurality of machines, the target capacity calculation unit 42 calculates the target capacity of each heat source machine 5 by using the maximum operation capacity, the aptitude operation capacity, and the lowest operation capacity.
The maximum operation capacity is a maximum capacity that the heat source machine 5 can output, and is determined, for example, based on a maximum frequency that the compressor 11 can output.
The appropriate operation capacity is, for example, a capacity at which the efficiency of the heat source machine 5 is equal to or higher than a predetermined value, and is, for example, a capacity at which the coefficient of performance (COP) is equal to or higher than a predetermined value. In the present embodiment, the appropriate operation capacity refers to a capacity appropriately set in a capacity range in which the COP is equal to or higher than a predetermined value. The compressor 11 has maximum efficiency during a partial load operation. The appropriate operation capacity may be variable, and an efficient value may be selected depending on the operation status of the heat source system 3 or the AHU 2.
The lowest operation capacity is a minimum capacity at which the heat source machine 5 can maintain a stable output, and is determined, for example, based on a minimum frequency at which the compressor 11 can maintain a stable output. The compressor 11 cannot be operated at a frequency lower than the minimum frequency. Therefore, the compressor 11 is activated at the lowest frequency regardless of the required capacity. In the present embodiment, the lowest operation capacity is, for example, 25%.
When the compressor 11 of the heat source machine 5 continues to be driven at a frequency ratio of 100%, the efficiency is not good and mechanical stress is applied. Therefore, the target capacity calculation unit 42 calculates the target capacity of the heat source machine 5 with respect to the required capacity such that the heat source machine 5 avoids driving at 100% and is operated efficiently, and the operating life of the compressor 11 is extended.
In a case where the target capacities of all heat source machines 5 reach the appropriate operation capacity after the control as described above is performed, the target capacity of each heat source machine 5 is increased to the maximum operation capacity of 100% at the same ratio as the required capacity increases.
In addition, in a case where the system controller 10 has a function as a master machine that controls the heat source system 3, the system controller 10 may have the same functions as the heat source machine controller 8a. In that case, each heat source machine controller 8 is a slave machine that is operated by a command of the system controller 10.
In addition, in a case where the heat source system 3 is controlled by the system controller 10, the system controller 10 includes a configuration and a function for realizing the above-described configuration and function included in the heat source machine controller 8a.
Fig. 7 is a flowchart showing an example of the processing procedure of a control method for the heat source system executed by the heat source machine controller according to an embodiment of the present disclosure.
In step S101, it is determined whether or not the target capacity of the i-th heat source machine 5 has reached 100%, which is the maximum operation capacity. When it is determined that the target capacity of the heat source machine 5 has reached 100%, the process proceeds to step S102. On the other hand, in a case where it is determined that the target capacity has not reached 100%, the process returns to step S101 again.
In step S102, when the target capacity of the i-th heat source machine 5 is set to the appropriate operation capacity, it is determined whether or not the target capacity of the i+1-th machine, which is a value obtained by subtracting the target capacity of the i-th heat source machine 5 from the required capacity, falls below the lowest operation capacity. When it is determined that the target capacity of the i+1-th machine falls below the lowest operation capacity, the process proceeds to step S103. On the other hand, when it is determined that the target capacity of the i+1-th machine does not fall below the lowest operation capacity, the process proceeds to step S108.
In step S103, the target capacity of the i+1-th machine is set to the lowest operation capacity, and the target capacity of the i-th machine is set to a value obtained by subtracting the lowest operation capacity of the i+1-th machine from 100%, which is the maximum operation capacity.
In step S103, in a case where the number of the heat source machines 5 is three or more and the third and subsequent heat source machines 5 are activated, the calculation is as follows. In a case where the number of the heat source machines 5 being driven is m, the target capacity of the i+1 (m+1)-th machine is set to the lowest operation capacity, and the target capacity of each of the first to m-th heat source machines 5 is set to a value obtained by dividing a value obtained by subtracting the lowest operation capacity from the required capacity by m.
In step S104, the target capacity of the i-th machine is increased in accordance with an increase in the required capacity.
In step S105, it is determined whether or not the target capacity of the i-th machine has reached the appropriate operation capacity. When it is determined that the target capacity of the i-th machine has reached the appropriate operation capacity, the process proceeds to step S106. On the other hand, when it is determined that the target capacity of the i-th machine has not reached the appropriate operation capacity, the process returns to step S104 again.
In step S106, the target capacity of the i+1-th machine is increased in accordance with an increase in the required capacity.
In step S107, the i+1-th machine is set as the i-th machine.
In step S102, it is determined that the target capacity of the i+1-th machine does not fall below the lowest operation capacity, the target capacity of the i-th machine is set to the appropriate operation capacity, and the target capacity of the i+1-th machine is set to a value obtained by subtracting the appropriate operation capacity of the i-th machine from 100%, which is the maximum operation capacity (S108).
In a case where the target capacities of all heat source machines 5 reach the appropriate operation capacity, the target capacity of each heat source machine 5 is increased to the maximum operation capacity of 100% at the same ratio as the required capacity increases.
Hereinafter, cases where the appropriate operation capacities are different will be described with reference to the drawings, respectively. In any case, the lowest operation capacity of each heat source machine 5 is assumed to be 25%. In addition, in any case, it is assumed that the appropriate operation capacities and the lowest operation capacities of the heat source machines 5 are the same, respectively, and the number of heat source machines 5 included in the heat source system 3 is 3.

[In Case Where Appropriate Operation Capacity Is 60%]

Fig. 8 is a diagram showing a target capacity for a required capacity of an entire system according to an embodiment of the present disclosure.
The air-conditioning system 1 is activated, and the first heat source machine 5a is activated at the lowest operation capacity. At this time, the lowest operation capacity of the heat source machine 5a is 25%. When the required capacity increases, the target capacity control unit 41 increases the target capacity of the heat source machine 5a accordingly.
When the target capacity of the heat source machine 5a reaches the maximum operation capacity of 100%, the target capacity calculation unit 42 determines whether or not the target capacity of the second heat source machine 5b falls below the lowest operation capacity of 25% when the target capacity of the first heat source machine 5a is set to 60%, which is the appropriate operation capacity. In this case, since the target capacity of the second heat source machine 5b is 40% and does not fall below 25%, the target capacity of the first heat source machine 5a is set to 60%, which is the appropriate operation capacity, and the target capacity of the second heat source machine 5b is set to 40%.
When the required capacity increases, the target capacity control unit 41 increases the target capacity of the second heat source machine 5b accordingly.
When the target capacity of the second heat source machine 5b reaches the maximum operation capacity of 100%, that is, the required capacity reaches 160%, the target capacity calculation unit 42 sets the target capacity of the second heat source machine 5b to 60%, which is the appropriate operation capacity. In addition, it is determined whether or not the target capacity of the third heat source machine 5c falls below the lowest operation capacity of 25%. In this case, since the target capacity of the third heat source machine 5c is 40% and does not fall below 25%, the target capacity of the second heat source machine 5b is set to 60%, which is the appropriate operation capacity, and the target capacity of the third heat source machine 5c is set to 40%.
When the required capacity increases, the target capacity control unit 41 increases the target capacity of the third heat source machine 5c accordingly.
When the target capacity of the third heat source machine 5c reaches 60%, which is the appropriate operation capacity, that is, the required capacity reaches 180%, the target capacity calculation unit 42 increases each target capacity of each of the heat source machines 5a, 5b, and 5c to the maximum operation capacity of 100% at the same ratio in accordance with the increase in the required capacity, that is, until the required capacity reaches 300%.

[In Case Where Appropriate Operation Capacity Is 75%]

Fig. 9 is a diagram showing the target capacity for the required capacity of the entire system according to an embodiment of the present disclosure.
The air-conditioning system 1 is activated, and the first heat source machine 5a is activated at the lowest operation capacity. At this time, the lowest operation capacity of the heat source machine 5a is 25%. When the required capacity increases, the target capacity control unit 41 increases the target capacity of the heat source machine 5a accordingly.
When the target capacity of the heat source machine 5a reaches the maximum operation capacity of 100%, the target capacity calculation unit 42 determines whether or not the target capacity of the second heat source machine 5b falls below the lowest operation capacity of 25% when the target capacity of the first heat source machine 5a is set to 75%, which is the appropriate operation capacity. In this case, since the target capacity of the second heat source machine 5b is 25% and does not fall below 25%, the target capacity of the first heat source machine 5a is set to 75%, which is the appropriate operation capacity, and the target capacity of the second heat source machine 5b is set to 25%.
When the required capacity increases, the target capacity control unit 41 increases the target capacity of the second heat source machine 5b accordingly.
When the target capacity of the second heat source machine 5b reaches the maximum operation capacity of 100%, that is, the required capacity reaches 175%, the target capacity calculation unit 42 sets the target capacity of the second heat source machine 5b to 75%, which is the appropriate operation capacity. In addition, it is determined whether or not the target capacity of the third heat source machine 5c falls below the lowest operation capacity of 25%. In this case, since the target capacity of the third heat source machine 5c is 25% and does not fall below 25%, the target capacity of the second heat source machine 5b is set to 75%, which is the appropriate operation capacity, and the target capacity of the third heat source machine 5c is set to 25%.
When the required capacity increases, the target capacity control unit 41 increases the target capacity of the third heat source machine 5c accordingly.
When the target capacity of the third heat source machine 5c reaches 75%, which is the appropriate operation capacity, that is, the required capacity reaches 225%, the target capacity calculation unit 42 increases each target capacity of each of the heat source machines 5a, 5b, and 5c to the maximum operation capacity of 100% at the same ratio in accordance with the increase in the required capacity, that is, until the required capacity reaches 300%.

[In Case Where Appropriate Operation Capacity Is 80%]

Fig. 10 is a diagram showing the target capacity for the required capacity of the entire system according to an embodiment of the present disclosure.
The air-conditioning system 1 is activated, and the first heat source machine 5a is activated at the lowest operation capacity. At this time, the lowest operation capacity of the heat source machine 5a is 25%. When the required capacity increases, the target capacity control unit 41 increases the target capacity of the heat source machine 5a accordingly.
When the target capacity of the heat source machine 5a reaches the maximum operation capacity of 100%, the target capacity calculation unit 42 determines whether or not the target capacity of the second heat source machine 5b falls below the lowest operation capacity of 25% when the target capacity of the first heat source machine 5a is set to 80%, which is the appropriate operation capacity. In this case, since the target capacity of the second heat source machine 5b is 20% and falls below 25%, the target capacity of the second heat source machine 5b is set to 25%, which is the lowest operation capacity, and the target capacity of the first heat source machine 5a is set to 75%.
When the required capacity increases, the target capacity control unit 41 increases the target capacity of the first heat source machine 5a accordingly. When the target capacity of the first heat source machine 5a reaches 80%, which is the appropriate operation capacity, that is, the required capacity reaches 105%, the target capacity control unit 41 increases the target capacity of the second heat source machine 5b in accordance with the increase in the required capacity.
When the target capacity of the second heat source machine 5b reaches the maximum operation capacity of 100%, that is, the required capacity reaches 180%, the target capacity calculation unit 42 determines whether or not the target capacity of the third heat source machine 5c falls below the lowest operation capacity of 25% when the target capacity of the second heat source machine 5b is set to 80%, which is the appropriate operation capacity. In this case, since the target capacity of the third heat source machine 5c is 20% and falls below 25%, the target capacity of the third heat source machine 5c is set to 25%, which is the lowest operation capacity, and the target capacity of the second heat source machine 5b is set to 75%.
When the required capacity increases, the target capacity control unit 41 increases the target capacity of the second heat source machine 5b accordingly. When the target capacity of the second heat source machine 5b reaches 80%, which is the appropriate operation capacity, that is, the required capacity reaches 185%, the target capacity control unit 41 increases the target capacity of the third heat source machine 5c in accordance with the increase in the required capacity.
When the target capacity of the third heat source machine 5c reaches 80%, which is the appropriate operation capacity, that is, the required capacity reaches 240%, the target capacity calculation unit 42 increases each target capacity of each of the heat source machines 5a, 5b, and 5c to the maximum operation capacity of 100% at the same ratio in accordance with the increase in the required capacity, that is, until the required capacity reaches 300%.
In the present embodiment, the heat source machine controller 8a includes the target capacity control unit 41 and the target capacity calculation unit 42 to control the number of the heat source machines 5 in operation and the target capacity allocated to each heat source machine 5. However, the functions performed by the master heat source machine controller 8a may be provided in the system controller 10.
That is, the system controller 10 calculates the required capacity and controls the number of the plurality of heat source machines 5 in operation and the target capacity allocated to each heat source machine 5 based on the calculated required capacity.

The heat source system, the air-conditioning system, the control method, and the control program described in the above-described embodiment are grasped as follows, for example.
A heat source system (3) according to a first aspect of the present disclosure is a heat source system that supplies a heat medium to a usage-side unit (2), the heat source system including: a plurality of heat source machines (5); and a heat source machine controller (8a) that controls the number of the plurality of heat source machines in operation and a target capacity allocated to each of the heat source machines according to a required capacity required by the usage-side unit, in which the heat source machine controller holds a maximum operation capacity and an appropriate operation capacity of each of the heat source machines, and activates a second heat source machine (5b) that is stopped and sets the target capacity of a first heat source machine (5a) among the heat source machines being operated to the appropriate operation capacity in a case where the target capacity allocated to the first heat source machine reaches the maximum operation capacity.
In this manner, it is possible to avoid an operation at the maximum operation capacity, increase efficiency of the compressor (11) of the first heat source machine by driving the compressor at a partial load, and extend an operating life. In addition, the load is shared by the plurality of heat source machines, the heat exchanger (13) can be effectively utilized, and the efficiency of the entire system can be increased.
In a heat source system according to a second aspect of the present disclosure, in the first aspect, when the target capacity allocated to the first heat source machine reaches the maximum operation capacity, the heat source machine controller may set the target capacity of the first heat source machine to the appropriate operation capacity and activate the second heat source machine at the target capacity obtained by subtracting the appropriate operation capacity of the first heat source machine from the required capacity.
In this manner, the first heat source machine can be driven at the appropriate operation capacity. In addition, the operating life can be extended. Since the load is shared by the plurality of heat source machines, the heat exchanger can be effectively utilized, and the efficiency of the entire system can be increased.
In a heat source system according to a third aspect of the present disclosure, in the second aspect, when the target capacity allocated to the first heat source machine reaches the maximum operation capacity, in a case where a value obtained by subtracting the appropriate operation capacity of the first heat source machine from the target capacity falls below a lowest operation capacity of the second heat source machine, the heat source machine controller activates the second heat source machine at the lowest operation capacity and sets the target capacity of the first heat source machine to a value obtained by subtracting the lowest operation capacity of the second heat source machine from the required capacity.
In this manner, the other heat source machine can be activated at the lowest operation capacity at which the heat source machine can operate, and the load can be shared by the plurality of heat source machines. Therefore, the heat exchanger can be effectively utilized.
In a heat source system according to a fourth aspect of the present disclosure, in the third aspect, the heat source machine controller may increase the target capacity of the first heat source machine to the appropriate operation capacity when the required capacity increases.
In this manner, the first heat source machine can be driven at the appropriate operation capacity at which the efficiency is maximized, and the efficiency of the entire system can be increased.
In a heat source system according to a fifth aspect of the present disclosure, in the fourth aspect, the heat source machine controller may increase the target capacities of all of the heat source machines by the same ratio in a case where the required capacity increases after all of the heat source machines reach the appropriate operation capacity.
In this manner, it is possible to perform an operation at a capacity corresponding to an increase in the required capacity while avoiding driving at the maximum operation capacity.
An air-conditioning system of a sixth aspect of the present disclosure may include, in any one of the first aspect to the fifth aspect, a heat source machine controller (8) provided to correspond to each of the plurality of the heat source machines and controlling a corresponding heat source machine, in which one of the heat source machine controllers may include the controller.
An air-conditioning system (1) of a seventh aspect of the present disclosure includes the heat source system according to any one of the first aspect to the sixth aspect, and an air handling unit (2) to which a heat medium is supplied from the heat source system.
A control method of an eighth aspect of the present disclosure is a control method for a heat source system including a plurality of heat source machines and supplying a heat medium to a usage-side unit, the method being executed by a computer and including: holding a maximum operation capacity and an appropriate operation capacity of each of the heat source machines; and activating a second heat source machine that is stopped and setting a target capacity of a first heat source machine among the heat source machines being operated to the appropriate operation capacity in a case where the target capacity allocated to the first heat source machine reaches the maximum operation capacity.
A control program of a ninth aspect of the present disclosure causes a computer to function as the heat source machine controller according to any one of the first aspect to the sixth aspect.

Reference Signs List

1: Air-conditioning system
2: AHU (direct expansion type air handling unit) (usage-side unit)
3: Heat source system
5: Heat source machine
5a: Heat source machine
5b: Heat source machine
5c: Heat source machine
7: Housing
8: Heat source machine controller
8a: Heat source machine controller (master)
8b: Heat source machine controller (slave 1)
8c: Heat source machine controller (slave 2)
10: System controller
11: Compressor
12: Switching valve
13: Heat exchanger
14: Fan
15: Accumulator
16: Electron expansion valve
21: Heat exchanger
21a: Heat exchanger
21b: Heat exchanger
21c: Heat exchanger
22: Temperature sensor
22a: Temperature sensor
22b: Temperature sensor
22c: Temperature sensor
23: Fan
24: Suction sensor
29: Remote controller
31: CPU
32: Main memory
33: Secondary storage
34: Communication interface
41: Target capacity control unit
42: Target capacity calculation unit

Claims

A heat source system that supplies a heat medium to a usage-side unit, the heat source system comprising:
a plurality of heat source machines; and

a controller that controls the number of the plurality of heat source machines in operation and a target capacity allocated to each of the heat source machines according to a required capacity required by the usage-side unit,

wherein the controller
holds a maximum operation capacity and an appropriate operation capacity of each of the heat source machines, and

activates a second heat source machine that is stopped and sets the target capacity of a first heat source machine among the heat source machines being operated to the appropriate operation capacity in a case where the target capacity allocated to the first heat source machine reaches the maximum operation capacity.
The heat source system according to Claim 1,
wherein when the target capacity allocated to the first heat source machine reaches the maximum operation capacity, the controller sets the target capacity of the first heat source machine to the appropriate operation capacity and activates the second heat source machine at the target capacity obtained by subtracting the appropriate operation capacity of the first heat source machine from the required capacity.
The heat source system according to Claim 2,
wherein when the target capacity allocated to the first heat source machine reaches the maximum operation capacity, in a case where a value obtained by subtracting the appropriate operation capacity of the first heat source machine from the target capacity falls below a lowest operation capacity of the second heat source machine, the controller activates the second heat source machine at the lowest operation capacity and sets the target capacity of the first heat source machine to a value obtained by subtracting the lowest operation capacity of the second heat source machine from the required capacity.
The heat source system according to Claim 3,
wherein the controller increases the target capacity of the first heat source machine to the appropriate operation capacity when the required capacity increases.
The heat source system according to Claim 4,
wherein the controller increases the target capacities of all of the heat source machines by the same ratio in a case where the required capacity increases after all of the heat source machines reach the appropriate operation capacity.
The heat source system according to any one of Claims 1 to 5, further comprising:
a heat source machine controller provided to correspond to each of the plurality of the heat source machines and controlling a corresponding heat source machine,

wherein one of the heat source machine controllers includes the controller.
An air-conditioning system comprising:
the heat source system according to any one of Claims 1 to 5; and

an air handling unit to which a heat medium is supplied from the heat source system.
A control method for a heat source system including a plurality of heat source machines and supplying a heat medium to a usage-side unit, the method being executed by a computer and comprising:
holding a maximum operation capacity and an appropriate operation capacity of each of the heat source machines; and

activating a second heat source machine that is stopped and setting a target capacity of a first heat source machine among the heat source machines being operated to the appropriate operation capacity in a case where the target capacity allocated to the first heat source machine reaches the maximum operation capacity.
A control program for causing a computer to function as the controller according to any one of Claims 1 to 5.