Air conditioning system

Abstract

To provide an air conditioning system capable of performing energy saving control through easy control by using a pump driven by an inverter-controlled motor.SOLUTION: An air conditioning system 1 includes: a pump 21 driven by a motor 22 and sending cold / hot water; a heat exchange device 12 heating or cooling the cold / hot water; an air conditioner 13 exchanging heat between the cold / hot water heated or cooled by the heat exchange device 12 and air; circulation piping 17 connecting the pump 21, the heat exchange device 12 and the air conditioner 13; a flow rate detector 15 detecting a minimum flow rate in the circulation piping 17; and a control section 19 changing operation frequency of the motor 22 at initial setting, setting operation frequency when the flow rate detector 15 detects the minimum flow rate as minimum operation frequency and performing variable speed control of the motor 22 between the minimum operation frequency and preset upper limit operation frequency in accordance with flow rate fluctuation instruction from the heat exchange device 12 and the air conditioner 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air conditioning system using a pump. [Background technology]

[0002] Air conditioning systems that control pumps to condition air have been known for some time. In order to predict the resistance characteristics of the pipes in such air conditioning systems, the flow rate is measured and the discharge pressure is calculated by the following formula: 2 A technique for controlling the temperature is known (see, for example, Patent Document 1).

[0003] In addition, a technique for frequency control of an air conditioning system is also known in which the differential pressure before and after the air conditioner (individual pump and fan coil unit) is set to zero using flow-differential pressure control (pressure is proportional to the square of the change in water volume) (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5476835 [Patent Document 2] Patent No. 3745357 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned technology requires complicated control. Therefore, in an air conditioning system having a circulation pipe that uses an inverter-controlled motor-driven pump, there is a demand for an energy-saving control of the pump that can be easily controlled.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an air conditioning system that uses an inverter-controlled motor-driven pump and can perform energy-saving control with simple control. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a system including: a motor; a pump driven by the motor for supplying cold or hot water; a heat exchanger for heating or cooling the cold or hot water; an air conditioner for exchanging heat between air and the cold or hot water heated or cooled by the heat exchanger; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; and a flow detector for detecting a minimum flow rate in the circulation pipe. a variable speed control device mounted on the motor for variably controlling the speed of the motor; a control unit that changes the operating frequency of the motor at the time of initial setting, sets the operating frequency when the flow rate detector detects the minimum flow rate as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchange device and the air conditioner. The control unit gradually increases the operating frequency of the motor from 0 during the initial setting to set the minimum operating frequency. . [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an air conditioning system that can perform energy saving control with simple control by using a motor-driven pump that is inverter-controlled. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing the configuration of an air conditioning system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the configuration of a control unit of the air conditioning system. [Figure 3] 4 is a flowchart showing an example of a method for setting the minimum operating frequency of the control unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] An example of an air conditioning system 1 according to an embodiment will be described below with reference to FIGS.

[0011] FIG. 1 is an explanatory diagram that schematically shows the configuration of an air conditioning system 1 according to an embodiment of the present invention, and FIG. 2 is a block diagram that shows an example of the configuration of a control unit 19 of the air conditioning system 1. As shown in FIG.

[0012] An air conditioning system 1 is installed in, for example, a building or the like, and conditions the air inside the building. As shown in Fig. 1, the air conditioning system 1 includes a pump unit 11, a heat exchanger 12, an air conditioner 13, an automatic control valve 14, a flow rate detector 15, a pressure detector 16, a circulation pipe 17, and a control unit 19. Such an air conditioning system 1 conditions the air by circulating cold or hot water through the pump unit 11, the heat exchanger 12, the air conditioner 13, and the automatic control valve 14 via the circulation pipe 17.

[0013] The pump unit 11 has a pump 21 and a motor 22. The pump 21 is driven under constant target pressure control by the motor 22 being variably controlled by the control unit 19. Note that although the example of this embodiment will be described as a configuration in which one pump unit 11 is provided, a plurality of pump units 11 may be provided.

[0014] The primary and secondary sides of the pump 21 are connected to the circulation pipe 17. The pump 21 sucks in the cold or hot water flowing through the circulation pipe 17, increases the pressure of the water, and discharges it into the circulation pipe 17. The pump 21 is, for example, a centrifugal pump. The motor 22 is, for example, a synchronous motor equipped with a permanent magnet.

[0015] The heat exchanger 12 is a heat source device including a heat source device and / or a cooling device. The heat exchanger 12 adjusts the temperature of the cold / hot water discharged from the pump 21 to a predetermined value by heating or cooling it. The heat exchanger 12 outputs, as signals, information on the flow rate of the cold / hot water passing through it and heat exchange of the cold / hot water to the control unit 19. The heat exchanger 12 also outputs a flow rate fluctuation instruction to the control unit 19 based on the flow rate of the cold / hot water passing through it and the information on heat exchange of the cold / hot water. Here, the flow rate fluctuation instruction is a flow rate command for changing the flow rate of the cold / hot water discharged from the pump 21. The heat exchanger 12 may be configured to output a flow rate command to the automatic control valve 14 to control the automatic control valve 14. The flow rate command (flow rate fluctuation instruction) output by the heat exchanger 12 to the control unit 19 is, for example, a command (frequency command) for an operating frequency proportional to the flow rate. This frequency command may be a specific frequency or an instruction to increase or decrease the frequency.

[0016] The air conditioner 13 exchanges heat between the air in the room to be air-conditioned and chilled / hot water. For example, the air conditioner 13 blows the air that has exchanged heat with chilled / hot water into the room. The air conditioner 13 outputs information about the chilled / hot water passing through it and about the heat exchange with the room air as signals to the control unit 19. The air conditioner 13 outputs information about the flow rate of the chilled / hot water passing through it and about the heat exchange with the chilled / hot water as signals to the control unit 19. The air conditioner 13 also outputs a flow rate fluctuation instruction to the control unit 19 based on the flow rate of the chilled / hot water passing through it and the information about the heat exchange with the chilled / hot water. Here, the flow rate fluctuation instruction is a flow rate command for changing the flow rate of the chilled / hot water discharged from the pump 21. The air conditioner 13 may be configured to output a flow rate command to the automatic control valve 14 and control the automatic control valve 14. The flow rate command (flow rate fluctuation instruction) output by the air conditioner 13 to the control unit 19 is, for example, a command (frequency command) for an operating frequency proportional to the flow rate. This frequency command may be a specific frequency or may be an instruction to increase or decrease the frequency.

[0017] One or more automatic control valves 14 may be provided. For example, when a single automatic control valve 14 is provided, the automatic control valve 14 is configured to be able to adjust its opening based on commands from the heat exchanger 12, the air conditioner 13, and / or the control unit 19. For example, when a plurality of automatic control valves 14 are provided, the plurality of automatic control valves 14 are connected in parallel and configured to be able to adjust the opening of each of the plurality of automatic control valves 14 or selectively, based on commands from the control unit 19, or the plurality of automatic control valves 14 selectively open and close. In other words, the single or multiple automatic control valves 14 adjust the flow rate of hot and cold water based on signals from the control unit 19.

[0018] The flow rate detector 15 detects the minimum flow rate of the hot and cold water flowing at least in the circulation pipe 17, and outputs a detection signal to the control unit 19. The flow rate detector 15 is provided, for example, on the primary side of the pump 21. As a specific example, the flow rate detector 15 detects the minimum flow rate on the suction side of the pump 21, and outputs a detection signal to the control unit 19. For example, the flow rate detector 15 transmits the detection signal to the control unit 19 by wire or wirelessly.

[0019] The pressure detector 16 outputs the pressure of the hot and cold water in the circulation pipe 17 as a signal to the control unit 19. The pressure detector 16 is provided, for example, on the primary side of the pump 21. The pressure detector 16 linearly detects the pressure in the circulation pipe 17 connected to the suction side of the pump 21, and outputs the obtained detection signal to the control unit 19. For example, the pressure detector 16 transmits the detection signal to the control unit 19 by wire or wirelessly.

[0020] The circulation pipe 17 forms a circulation flow path that circulates through the pump 21, the heat exchanger 12, and the air conditioner 13. The circulation pipe 17 sends cold and hot water using the pump 21, passes it through the heat exchanger 12 and the air conditioner 13, and returns it to the pump 21.

[0021] The control unit 19 controls the motor 22. The control unit 19 includes, for example, a variable speed control device 51, a communication unit 52, an input unit 53, an interface 54, a display unit 55, a storage unit 56, and a processor 57. The control unit 19 is, for example, a control panel or a control terminal in which the variable speed control device 51, the communication unit 52, the input unit 53, the interface 54, the display unit 55, the storage unit 56, and the processor 57 are integrated into a single unit. Note that the control unit 19 may be configured such that some of its components are mounted in a separate housing and provided in different positions. For example, the control unit 19 may be configured such that the variable speed control device 51 is mounted on the motor 22 and the other components are provided in an integrated housing.

[0022] Control unit 19 is electrically connected to motor 22, and controls the rotation speed of pump 21 by controlling the driving of motor 22. Specifically, control unit 19 drives motor 22 via variable speed control device 51 and variably controls the operating frequency of motor 22 based on flow rate commands from heat exchanger 12 and / or air conditioner 13, and detection signals from flow rate detector 15 and / or pressure detector 16, etc.

[0023] For example, the control unit 19 is electrically connected to the interface 54 via a signal line or the like, or wirelessly connected to the flow rate detector 15 and the pressure detector 16 via the communication unit 52. The control unit 19 stops and starts the motor 22 and controls the operating frequency based on constant target pressure control, based on detection signals corresponding to the flow rate detected by the flow rate detector 15 and the pressure detected by the pressure detector 16, and on load and flow rate fluctuation instructions output from the heat exchanger 12 and the air conditioner 13.

[0024] Here, the target pressure constant control refers to constant control of the pressure detected by the pressure detector 16 or the discharge pressure estimated from the pump 21, or constant control of the estimated terminal pressure taking into account the piping resistance. The rotation speed of the pump 21 is the same as the rotation speed (operating frequency) of the motor 22, and the rotation speed of the pump 21 (motor 22) has a certain relationship with the operating frequency of the variable speed control device 51.

[0025] Furthermore, in addition to controlling the pump unit 11, the control unit 19 may wirelessly connect to an external communication terminal and transmit operating data to the communication terminal as appropriate. Such a configuration involving communication with a communication terminal constitutes an air conditioning management system or the like that includes the control unit 19 and the communication terminal. Such a configuration may also constitute a management system that includes the control unit 19 and a program executed by the communication terminal, or a management system that includes the air conditioning system 1 and a program executed by the communication terminal.

[0026] The variable speed control device 51 is an inverter that controls the motor 22. For example, the number of variable speed control devices 51 provided is the same as the number of motors 22. The variable speed control device 51 receives an inverter control signal from the processor 57. The variable speed control device 51 operates in response to the inverter control signal. For example, the variable speed control device 51 stops or starts the operation of the motor 22 in response to an inverter control signal equivalent to an operation stop signal or an operation start signal. The variable speed control device 51 also controls the operating frequency of the motor 22 (the rotation speed of the pump 21) in response to an inverter control signal equivalent to a rotation speed control signal. The variable speed control device 51 has an inverter control board that includes, for example, a noise filter, a reactor for high frequency suppression, an earth leakage breaker, etc.

[0027] The communication unit 52 is an arbitrary communication interface that is controlled by the processor 57 and is capable of communicating with an external device such as a communication terminal using wireless communication technology. The communication unit 52 may also be configured to receive information from the heat exchanger 12, the air conditioner 13, the flow rate detector 15, and the pressure detector 16 using wireless communication technology, and to transmit the information to the heat exchanger 12 and the air conditioner 13.

[0028] The communication unit 52 may be implemented as, for example, a communication module or a communication board. The communication module may be detachably provided on a control board of the control unit 19 via, for example, a connector. Specifically, the communication unit 52 can be connected to an external device such as a communication terminal using, for example, wireless communication technology such as the Bluetooth (registered trademark) Low Energy standard (hereinafter also referred to as the BLE standard), Wi-Fi (registered trademark), or NFC, or wired communication technology such as USB.

[0029] The BLE standard may be, for example, BLE version 4.0 or later, and may be compatible with the BLE communication method. Accordingly, the "BLE standard" may be referred to as "Bluetooth 4.0 or later." The communication unit 52 may also receive some data for establishing a connection between the communication terminal and the control unit 19, such as a request from the communication terminal as a scanner when the communication terminal and the control unit 19 are connected via Bluetooth as a scanner and an advertiser, respectively.

[0030] The input unit 53 includes at least one of a device for accepting user input, such as an operation panel including buttons, a touch panel, a keyboard, a mouse, etc., and a sensor, such as a pressure sensor, a microphone, a camera, etc. The input unit 53 is a device for accepting user input, which is an arbitrary command from the user, such as parameter setting, initial setting, setting of each operation mode, etc.

[0031] The interface 54 is a terminal or circuit to which the heat exchanger 12, the air conditioner 13, the flow rate detector 15, the pressure detector 16, and an external terminal can be electrically connected by wire. That is, the heat exchanger 12, the air conditioner 13, the flow rate detector 15, and the pressure detector 16 are connected to the processor 57 wirelessly by the communication unit 52 or by wire via the interface 54.

[0032] The display unit 55 has a display device such as a liquid crystal display or an organic EL display, etc. Furthermore, the display unit 55 may have a speaker, an LED (Light Emitting Diode) lighting unit, etc. instead of or in addition to the display device.

[0033] The storage unit 56 is capable of reading and writing data. Here, the storage unit 56 refers to a storage medium, and includes so-called memory and storage. The storage unit 56 includes a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) (registered trademark), a ROM (Read only memory), or a NAND flash memory. The storage unit 56 also includes an SSD (Solid State Drive) equipped with a flash memory. In addition to the nonvolatile memory, the storage unit 56 may also include a RAM having a work area in which data that may be erased when the power is turned off is developed.

[0034] The memory unit 56 stores data used by the processor 57, operating data of the pump unit 11, the heat exchanger 12, and the air conditioner 13, and various data and programs used to control the pump unit 11, the heat exchanger 12, and the air conditioner 13.

[0035] The data stored in the memory unit 56 includes, for example, identification information, codes, tables, etc. that identify the control unit 19. The operating data stored is periodically acquired operating data that indicates the operating states of the pump unit 11, the heat exchanger 12, and the air conditioner 13. The memory unit 56 also stores external parameters and internal parameters required for control and correction of the pump unit 11, the heat exchanger 12, and the air conditioner 13.

[0036] The processor 57 is an overall control unit. The processor 57 performs any processing, such as communication control, display control, and pump control. As shown in Fig. 2, the processor 57 is connected to, for example, the variable speed control device 51, the communication unit 52, the input unit 53, the interface 54, the display unit 55, and the storage unit 56, and controls each component. As shown in Fig. 2, the processor 57 is connected to, for example, the heat exchanger 12, the air conditioner 13, the automatic control valve 14, the flow rate detector 15, the pressure detector 16, and the motor 22 of the pump unit 11 via the variable speed control device 51, the communication unit 52, the interface 54, etc.

[0037] The processor 57 is a microcomputer, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processor), or any other general-purpose or dedicated processor.

[0038] The processor 57 includes, for example, a processing circuit and a memory. The processor 57 includes, for example, a non-volatile EEPROM area and a volatile DRAM area. The processor 57 can also function as a processing unit, a pump control unit, etc. by executing a program stored in the storage unit 56 or the EEPROM area. The division of functions among the various units within the processor 57 is for convenience and can be changed as appropriate.

[0039] The programs stored may include, for example, firmware, an OS, a processing program mainly related to parameter processing, a pump control program (e.g., an automatic operation program), etc. The programs may be acquired from the storage unit 56 by the processor 57 and stored in the EEPROM area when the power is turned on, for example. Alternatively, the programs may be stored in the storage unit 56 but not in the EEPROM area, and the processor 57 may execute the programs stored in the storage unit 56.

[0040] The following describes an example of the function of the processor 57. Here, the control function is a process in which the processor 57 drives the pump 21 in a constant target pressure control operation based on a program.

[0041] Processor 57 drives motor 22 at a predetermined operating frequency under predetermined conditions based on a program, thereby driving pump 21 under constant target pressure control. When driving pump 21 under constant target pressure control, processor 57 also drives motor 22 in a predetermined operating frequency band.

[0042] That is, when the processor 57 drives the pump 21 under constant target pressure control, the processor 57 changes the operating frequency for driving the motor 22 between a lower limit operating frequency and an upper limit operating frequency. As a specific example, the processor 57 drives the motor 22 by changing the operating frequency between the lower limit operating frequency and the upper limit operating frequency in response to a flow rate fluctuation command from an air conditioning control device including the heat exchanger 12 and / or the air conditioner 13.

[0043] Here, the lower limit operating frequency is the minimum operating frequency set at the time of initial setup. As a specific example, at the time of initial setup, the processor 57 changes the operating frequency at which the motor 22 is driven to drive the pump, and the operating frequency at which the flow rate detector 15 detects the minimum flow rate is set in the memory unit 56 as the minimum operating frequency Smin. Here, when determining the minimum operating frequency Smin, preferably, the processor 57 gradually increases the operating frequency at which the motor 22 is driven from 0, and stores the operating frequency at which the flow rate detector 15 detects the minimum flow rate in the memory unit 56 as the minimum operating frequency Smin.

[0044] As another example, the minimum operating frequency may be determined by changing the operating frequency at which the processor 57 drives the motor 22 to drive the pump 21 during initial setting, and storing the operating frequency at which the pressure detected by the pressure detector 16 is equal to the minimum pressure Pmin on the primary side of the pump 21 that is set in advance and stored in the memory 56 as the minimum operating frequency Smin in the memory 56. When determining the minimum operating frequency Smin, the processor 57 preferably gradually increases the operating frequency at which the pressure detected by the pressure detector 16 is equal to the minimum pressure Pmin on the primary side of the pump 21 that is set in advance and stored in the memory 56, and stores this operating frequency as the minimum operating frequency Smin in the memory 56. The minimum pressure Pmin is the lower limit of the pressure in the circulation pipe 17, or more specifically, the primary side of the pump 21, when the pump 21 is controlled to be driven under constant target pressure control.

[0045] As another example, the minimum operating frequency Smin may be set to the higher of the operating frequency when the above-mentioned minimum flow rate is detected by the flow rate detector 15 and the operating frequency when the above-mentioned primary side minimum pressure Pmin is detected by the pressure detector 16.

[0046] The upper limit operating frequency is stored and set in advance in the storage unit 56. The upper limit operating frequency is, for example, the maximum operating frequency Smax that takes into account the maximum capacity of the pump 21, and is stored in advance in the storage unit 56 by receiving information via an input from the input unit 53 or via the communication unit 52. Note that the upper limit operating frequency is not limited to this, and it is sufficient that the upper limit operating frequency is a frequency that is higher than the minimum operating frequency Smin (lower limit operating frequency) and that can exhibit the performance required of the air conditioning system 1, and the upper limit operating frequency may be a frequency based on the maximum capacity of the air conditioning system 1, or may be another frequency.

[0047] Furthermore, when the processor 57 drives the motor 22 (pump 21) at an operation frequency between the minimum operation frequency Smin and the maximum operation frequency Smax, the processor 57 controls the driving of the motor 22 so that the pressure on the primary side of the pump 21 is always positive (Pmin>0) or is equal to or greater than the minimum compression pressure of the pump 21. For example, the minimum pressure of the pump 21 is set so that the pressure on the primary side of the pump 21 is positive or equal to or greater than the minimum compression pressure of the pump 21.

[0048] The processor 57 may set the minimum operating frequency or manage the minimum pressure on the primary side of the pump 21 so that the pressure on the primary side of the pump 21 is always positive or so that the pressure is equal to or greater than the minimum pushing pressure of the pump 21. As a specific example, the minimum operating frequency is set to a frequency at which the pressure on the primary side of the pump 21 is positive, and the processor 57 controls the drive of the motor 22 with this minimum operating frequency as the lower limit operating frequency, thereby keeping the pressure on the primary side of the pump 21 always positive.

[0049] In other words, when the motor 22 is controlled at a variable speed using constant target pressure control, the processor 57 compensates the pressure on the primary side of the pump 21 to be positive pressure or the minimum pressure by setting a minimum pressure that becomes positive at the minimum operating frequency so that the pressure on the primary side of the pump 21 is always positive pressure or a pressure higher than the minimum pressure of the pump 21 when the pump 21 is driven.

[0050] Furthermore, instead of setting the value Smin of the operating frequency found at the minimum flow rate or the minimum pressure as the minimum operating frequency, the processor 57 may set the minimum operating frequency to a value Smin+α obtained by adding a margin α previously set in the memory unit 56 to the value Smin. Here, the margin α is a correction value for increasing the operating frequency Smin, which is set as the minimum operating frequency, taking into account the aging of components of the air conditioning system 1, such as the pump 21. This allows the processor 57 to perform reliable variable flow rate control without using the flow rate detector 15 when setting the minimum operating frequency.

[0051] In addition, the processor 57 may control the rotation speed of the motor 22 (pump 21) by adjusting the valve opening degree and the number of valve openings and closings of the automatic control valve 14 provided in the circulation pipe 17 in response to signals from an air conditioning control device including the heat exchanger 12 and the air conditioner 13, thereby achieving constant target pressure control that takes advantage of energy savings.

[0052] Next, an example of a method for setting the minimum operating frequency of the processor 57 will be described with reference to the flowchart of FIG. At the time of initial drive, the processor 57 drives the pump 21 (step ST1). Here, examples of the time of initial drive include when the air conditioning system 1 (controller 19) is powered on after installation of the air conditioning system 1, and when the air conditioning system 1 is powered on after maintenance. The time of initial drive also includes when an operator or the like inputs an initial drive command via the input unit 53.

[0053] The processor 57, for example, gradually increases the operating frequency of the pump 21 from 0, and starts detecting the flow rate using the flow rate detector 15 or the pressure using the pressure detector 16 (step ST2). Then, the processor 57 determines whether or not the flow rate detector 15 has detected a minimum flow rate, or whether or not the pressure detected by the pressure detector 16 is the minimum pressure Pmin (step ST3). If the flow rate detector 15 has not output a signal indicating the detection of the minimum flow rate, or if the pressure detected by the pressure detector 16 is lower than the minimum pressure Pmin (NO in step ST3), the processor 57 continues detecting the flow rate or pressure.

[0054] For example, when the operating frequency increases from 0, cold or hot water at a minimum flow rate flows through the circulation pipe 17, and the flow detector 15 receives a signal output by detecting the minimum flow rate, or the signal corresponding to the pressure output from the pressure detector 16 becomes the minimum primary side pressure Pmin (YES in step ST3), the processor 57 detects the operating frequency when the minimum flow rate or the minimum primary side pressure Pmin was detected (step ST4).

[0055] The processor 57 sets the detected operation frequency as the minimum operation frequency Smin (step ST5). As a specific example, the processor 57 stores the minimum operation frequency Smin in the storage unit 56, and when driving the pump 21 (motor 22) in the subsequent target pressure constant control, controls the driving of the pump 21 at an operation frequency between the minimum operation frequency Smin and the maximum operation frequency Smax, which is the upper limit of the operation frequency.

[0056] When adding the tolerance α to the minimum operating frequency in step ST5, the processor 57 stores the value Smin+α obtained by adding the tolerance α to the value of the operating frequency detected in step ST4 in the storage unit 56 as the minimum operating frequency.

[0057] According to the air conditioning system 1 configured in this manner, the variable speed control device 51 is provided, which allows variable speed control of the motor 22 by inverter control, and makes it possible to easily control the flow rate of the hot or cold water discharged from the pump 21 in response to flow rate commands from the heat exchanger 12 and the air conditioner 13. Furthermore, the air conditioning system 1 can use the processor 57 to control the pump 21 to a constant target pressure between the set minimum operating frequency and upper limit operating frequency (maximum operating frequency), thereby eliminating the need for complex control of the pump 21 or the use of devices or motor-operated valves, and enabling energy-saving control.

[0058] Furthermore, the air conditioning system 1 variably controls the speed of the motor 22 so that the primary pressure of the pump 21 is always positive or equal to or greater than the minimum pumping pressure of the pump 21. As a specific example, the air conditioning system 1 sets a minimum operating frequency (minimum pressure) or controls the motor 22 to manage the minimum primary pressure of the pump 21. This allows the air conditioning system 1 to prevent cavitation in the pump 21 not only when the water volume is small but also when the water volume is large.

[0059] Furthermore, by correcting the set minimum operating frequency with the tolerance α, the air conditioning system 1 can prevent the pressure in the circulation pipe 17 from dropping below the specified pressure when operating at the minimum operating frequency, even if deterioration occurs over time and the performance of the pump 21, etc., declines.

[0060] Furthermore, air conditioning system 1 is configured to drive pump 21, which is a centrifugal pump, by controlling motor 22 to drive at a variable speed between a set minimum operating frequency and a preset maximum operating frequency, thereby allowing flow detector 15 to have a simple and inexpensive configuration that can detect the minimum flow rate. That is, conventional air conditioning systems are known to control the flow rate by detecting the actual flow rate, but frequency control of a centrifugal pump is such that flow rate ∝ rotational speed ∝ operating frequency, and therefore, excluding piping resistance, the flow rate is approximately proportional to the operating frequency, so flow rate control is possible even if flow detector 15 is configured to be unable to detect the actual flow rate.

[0061] Furthermore, by using a synchronous motor as the motor 22, no slip occurs in the motor 22, and therefore the flow rate is proportional to the operating frequency excluding the piping resistance, and there is no need to consider the flow rate due to slip. Therefore, even in a configuration in which the flow detector 15 cannot detect the actual flow rate (a configuration in which actual flow rate control is not performed), flow rate control can be performed with high accuracy.

[0062] As described above, the air conditioning system 1 according to the embodiment can perform energy saving control with simple control using the pump 21 driven by the motor 22 that is inverter controlled.

[0063] The present invention is not limited to the above-described embodiment. For example, in the above example, the air conditioning system 1 is described as having a configuration including the flow rate detector 15 and the pressure detector 16, but is not limited to this. For example, the air conditioning system 1 may be configured to have either the flow rate detector 15 or the pressure detector 16.

[0064] In the above example, the air conditioning system 1 is described as having an automatic control valve 14, but the present invention is not limited to this, and the air conditioning system 1 may be configured to adjust the flow rate of hot and cold water by controlling the pump 21 to a constant target pressure without having the automatic control valve 14. Note that, since using the automatic control valve 14 causes losses, it is preferable that the air conditioning system 1 is configured without the automatic control valve 14.

[0065] In the above example, the control unit 19 has a configuration including the variable speed control device 51, but the present invention is not limited to this. That is, the variable speed control device 51 may be mounted on the motor 22, or may be an inverter circuit mounted on a board within the control unit 19. That is, the variable speed control device 51 can be set as appropriate as long as it is capable of variably controlling (inverter control) the motor 22.

[0066] In the above example, the air conditioning system 1 is configured to set the minimum operating frequency at the time of initial setup, but the present invention is not limited to this and may be configured to reset (update) the minimum operating frequency manually or automatically. In other words, the air conditioning system 1 may be configured to set the minimum operating frequency at the time of initial setup, as well as at the time of a user command and / or periodically.

[0067] For example, as a manual process, the processor 57 may set the minimum operating frequency when a command to set the minimum operating frequency is input from the user via the input unit 53. Alternatively, as an automatic process, the processor 57 may set the minimum operating frequency after a predetermined time has elapsed since the previous setting of the minimum operating frequency, or after the total driving time of the pump 21 has elapsed for a predetermined time. The predetermined time may be stored in the memory unit 56 in advance, or may be arbitrarily input via the input unit 53 and stored in the memory unit 56. Alternatively, as an automatic process, the processor 57 may set the minimum operating frequency when, for example, the air conditioning system 1 has little or no effect on the air conditioning. For example, the processor 57 may set the minimum operating frequency after a predetermined time has elapsed since the previous setting of the minimum operating frequency, or after the total driving time of the pump 21 has elapsed for a predetermined time, and when it is determined that the air conditioner 13 has sufficiently exchanged heat with the room and the room temperature has reached the desired room temperature, or when the air conditioning system 1 is stopped or started.

[0068] In the above example, the processor 57 sets the minimum operating frequency based on the flow rate or pressure detected when the operating frequency for driving the motor 22 is gradually increased, but the present invention is not limited to this. The minimum operating frequency may be set based on the flow rate or pressure detected when the operating frequency for driving the motor 22 is gradually decreased, or the higher of the operating frequencies obtained based on the flow rate or pressure during the increase and decrease may be set as the minimum operating frequency. However, since the operating frequency when the minimum flow rate or minimum pressure is reached when the operating frequency is decreased is a smaller value than the operating frequency when the minimum flow rate or minimum pressure is reached when the operating frequency is increased, it is preferable to set the minimum operating frequency by increasing the operating frequency.

[0069] Furthermore, in the above example, the flow detector 15 is configured to be able to detect a minimum flow rate, but the present invention is not limited to this and may be a flow transmitter that can detect the flow rate of the hot and cold water flowing linearly through the circulation pipe 17. For example, in the case of such a flow detector 15, a detected flow rate signal is transmitted to the control unit 19 by wire or wirelessly, and the processor 57 changes the operating frequency between the minimum operating frequency and the maximum operating frequency in accordance with the flow rate value received from the flow detector 15 and flow rate fluctuation instructions received from the heat exchanger 12, the air conditioner 13, etc.

[0070] That is, the present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. The following is a description equivalent to the invention described in the original claims of the present application. [1] A motor; a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a flow rate detector for detecting a minimum flow rate in the circulation pipe; a control unit that changes the operating frequency of the motor at the time of initial setting, defines the operating frequency when the flow rate detector detects the minimum flow rate as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchange device and the air conditioner; An air conditioning system equipped with: [2] A motor; a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a pressure detection unit provided on a primary side of the pump and detecting a pressure in the circulation pipe; a control unit that changes an operating frequency of the motor at an initial setting, sets the operating frequency when the pressure detected by the pressure detection unit reaches a preset minimum pressure as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchange device and the air conditioner; An air conditioning system equipped with: [3] A motor; a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a flow rate detector for detecting a minimum flow rate in the circulation pipe; a pressure detection unit provided on a primary side of the pump and detecting a pressure in the circulation pipe; a control unit that changes the operating frequency of the motor at the time of initialization, and sets the higher of the operating frequency when the flow rate detector detects the minimum flow rate and the operating frequency when the pressure detected by the pressure detection unit detects a preset minimum pressure as the minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchange device and the air conditioner; An air conditioning system equipped with: [4] The air conditioning system according to [1], further comprising a pressure detection unit provided on the primary side of the pump and detecting the pressure in the circulation pipe. [5] The air conditioning system described in [2], further comprising a flow rate detector for detecting a minimum flow rate in the circulation pipe. [6] An air conditioning system described in any one of [2] to [5], wherein the control unit controls the motor at a variable speed so that the pressure on the primary side of the pump becomes positive pressure or a pressure equal to or greater than the minimum pumping pressure of the pump. [7] The air conditioning system according to [7], wherein the pressure on the primary side of the pump is a positive pressure or a pressure equal to or greater than the minimum pump pressure, is the minimum pressure of the pump. [8] An air conditioning system described in any one of [1] to [7], wherein the control unit adds a preset tolerance to the minimum operating frequency and variably controls the motor between the minimum operating frequency plus the tolerance and the upper limit operating frequency. [9] One or more automatic control valves are provided in the circulation piping and are capable of adjusting the opening degree, The air conditioning system described in any one of [2] to [8], wherein the control unit adjusts the opening of the single automatic control valve based on a signal from the heat exchange device and / or the air conditioner, or adjusts the opening or opening / closing quantity of the multiple automatic control valves to control the motor at variable speed, thereby controlling the target pressure to a constant level.

[10] The flow rate detector is a flow rate transmitter that linearly detects a flow rate and outputs a signal, The air conditioning system according to any one of [1], [3] to [5], or [6] to [9] subordinate to [1], [3] to [5], wherein the control unit changes the operating frequency of the motor in response to a flow rate fluctuation instruction from the heat exchange device and / or the air conditioner.

[11] An air conditioning system according to any one of [1] to

[10] , wherein the control unit increases the operating frequency of the motor during the initial setting to set the minimum operating frequency.

[12] An air conditioning system according to any one of [1] to

[11] , wherein the upper limit of the operating frequency is a maximum operating frequency.

[13] An air conditioning system according to any one of [1] to

[12] , comprising a variable speed control device mounted on the motor that variably controls the speed of the motor.

[14] An air conditioning system according to any one of [1] to

[13] , wherein the motor is a synchronous motor equipped with a permanent magnet. [Explanation of symbols]

[0071] 1...air conditioning system, 11...pump unit, 12...heat exchange device, 13...air conditioner, 14...automatic control valve, 15...flow rate detector, 16...pressure detector, 17...circulation piping, 19...control unit, 21...pump, 22...motor, 51...variable speed control device, 52...communication unit, 53...input unit, 54...interface, 55...display unit, 56...memory unit, 57...processor

Claims

1. A motor; a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a flow rate detector for detecting a minimum flow rate in the circulation pipe; a control unit that has a variable speed control device mounted on the motor and that variably controls the speed of the motor, changes the operating frequency of the motor at the time of initial setting, and sets the operating frequency when the flow rate detector detects the minimum flow rate as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchanger and the air conditioner; Equipped with The control unit gradually increases the operating frequency of the motor from 0 during the initial setting to set the minimum operating frequency.

2. A motor; a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a pressure detection unit provided on a primary side of the pump and detecting a pressure in the circulation pipe; a control unit that has a variable speed control device mounted on the motor and that variably controls the speed of the motor, and that changes the operating frequency of the motor at an initial setting, and sets the operating frequency when the pressure detected by the pressure detection unit detects a preset minimum pressure as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchanger and the air conditioner; Equipped with The control unit gradually increases the operating frequency of the motor from 0 during the initial setting to set the minimum operating frequency.

3. A motor; a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a flow rate detector for detecting a minimum flow rate in the circulation pipe; a pressure detection unit provided on a primary side of the pump and detecting a pressure in the circulation pipe; a control unit that has a variable speed control device mounted on the motor and that variably controls the speed of the motor, and that changes the operating frequency of the motor at an initial setting, and sets the higher of the operating frequency when the flow rate detector detects the minimum flow rate and the operating frequency when the pressure detected by the pressure detection unit detects a preset minimum pressure as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchanger and the air conditioner; Equipped with The control unit gradually increases the operating frequency of the motor from 0 during the initial setting to set the minimum operating frequency.

4. A motor, a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a flow rate detector for detecting a minimum flow rate in the circulation pipe; a control unit that changes the operating frequency of the motor at the time of initial setting, defines the operating frequency when the flow rate detector detects the minimum flow rate as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchange device and the air conditioner; Equipped with The control unit resets the minimum operating frequency after a predetermined time stored in advance in the memory unit of the control unit has elapsed since the setting of the minimum operating frequency, or after the total driving time of the pump has elapsed a predetermined time.

5. A motor, a pump driven by the motor for supplying cold and hot water; A heat exchanger that heats or cools the cold or hot water; an air conditioner that exchanges heat between the cold or hot water heated or cooled by the heat exchanger and air; a circulation pipe connecting the pump, the heat exchanger, and the air conditioner; a pressure detection unit provided on a primary side of the pump and detecting a pressure in the circulation pipe; a control unit that changes an operating frequency of the motor at an initial setting, sets the operating frequency when the pressure detected by the pressure detection unit reaches a preset minimum pressure as a minimum operating frequency, and variably controls the speed of the motor between the minimum operating frequency and a preset upper limit operating frequency in response to flow rate fluctuation instructions from the heat exchange device and the air conditioner; Equipped with The control unit resets the minimum operating frequency after a predetermined time stored in advance in the memory unit of the control unit has elapsed since the setting of the minimum operating frequency, or after the total driving time of the pump has elapsed a predetermined time.

6. the control unit controls the motor to have a variable speed so that the pressure on the primary side of the pump is a positive pressure or a pressure equal to or greater than a minimum pressure of the pump; 6. The air conditioning system according to claim 1, wherein the pressure on the primary side of the pump is a positive pressure or a pressure equal to or greater than a minimum pump pressure of the pump, and the pressure on the primary side of the pump is the minimum pressure of the pump.

7. 7. The air conditioning system according to claim 1, wherein the control unit adds a preset tolerance to the minimum operating frequency and performs variable speed control of the motor between the minimum operating frequency plus the tolerance and the upper limit operating frequency.

8. One or more automatic control valves are provided in the circulation pipe and are capable of adjusting opening degrees, 8. The air conditioning system according to claim 1, wherein the control unit adjusts the opening of the single automatic control valve based on a signal from the heat exchanger and / or the air conditioner, or adjusts the opening or the number of openings and closings of the plurality of automatic control valves to variably control the motor, thereby controlling the target pressure to a constant level.

9. the flow rate detector is a flow rate transmitter that linearly detects a flow rate and outputs a signal; The air conditioning system according to claim 1 , wherein the control unit changes the operating frequency of the motor in response to a flow rate fluctuation instruction from the heat exchanger and / or the air conditioner.

10. An air conditioning system as described in claim 4 or claim 5, wherein the control unit resets the minimum operating frequency after a predetermined time has elapsed, when it determines that the room temperature has reached the desired room temperature, or when the system is stopped or started.

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