Air conditioning system and method for controlling air conditioning system

Abstract

To provide an air-conditioning system which is reduced in an energy amount to be consumed, and a control method of the air-conditioning system.SOLUTION: An air-conditioning system 1 comprises: a plurality of air conditioners 40 in which cold / how water circulates; a control valve 50 for controlling a flow rate of the cold / hot water circulating in each air conditioner 40; a cold / hot water pump 20 for supplying cold / hot water to the plurality of air conditioners 40; a detection part for detecting that an operation condition of the air conditioner 40 is adapted to a state of a preset element; a setting part 90 for setting a pressure difference of the cold / hot water pump 20; and a control part 70 for driving the cold / hot water pump 20 by an output of the cold / hot water pump 20 which is set by the setting part 90. When the detection part detects that a state of an element of the air conditioner 40 is adapted to the preset element, the setting part 90 sets the output of the cold / hot water pump to a second output.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air conditioning system and a method for controlling an air conditioning system. [Background technology]

[0002] Known conventional air conditioning systems include, for example, the air conditioning system described in Patent Document 1. Another known conventional air conditioning system includes a heat source, a plurality of air conditioners installed indoors and connected to the heat source by hot and cold water piping, and a pump installed in the hot and cold water piping to circulate the hot and cold water between the heat source and the air conditioners.

[0003] Furthermore, in conventional air conditioning systems, it is known to implement variable flow control, which aims to save energy by varying the pump rotation speed in accordance with the amount of chilled or hot water circulating in each air conditioner so that the flow rate of chilled or hot water circulating in each air conditioner is not insufficient in accordance with the air conditioning capacity required of each air conditioner. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-173221 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when variable flow control is implemented in conventional air conditioning systems, the pump's chilled / hot water differential pressure is set to a large differential pressure so that the required differential pressure for circulating chilled / hot water to each air conditioner is not insufficient, and the control valve for each air conditioner is used to reduce the pressure to a level corresponding to the required chilled / hot water flow rate.However, this pressure is too large compared to the required differential pressure, which causes a problem in that the amount of energy consumed by the air conditioning system increases.

[0006] The present invention has been made to solve such problems, and has an object to provide an air conditioning system and a control method for an air conditioning system that consumes a reduced amount of energy. [Means for solving the problem]

[0007] In order to solve the above problems, an air conditioning system according to the present invention includes a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, piping sequentially connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, a detection unit for detecting whether the state of an element related to the operation of the air conditioner conforms to a state of a preset element, and a pressure difference between the upstream side and the downstream side of the chilled or hot water pump when the pressure difference between the upstream side and the downstream side of the chilled or hot water pump is greater than or equal to the pressure difference between the upstream side and the downstream side of the chilled or hot water pump and the downstream side of the chilled or hot water pump. The system includes a setting unit that sets the output of the chilled / hot water pump so as to achieve a differential pressure necessary for the circulation of a total air conditioner flow rate required by a system including the air conditioner and piping, and a control unit that controls the chilled / hot water pump with the output of the chilled / hot water pump set by the setting unit, wherein when the detection unit detects that the state of the air conditioner element does not match the state of the element set in advance, the setting unit sets the chilled / hot water pump output to a first output, and when the detection unit detects that the state of the air conditioner element matches the state of the element set in advance, the setting unit sets the chilled / hot water pump output to a second output. The detection unit includes an air conditioner flow rate detection unit that measures the air conditioner flow rate for each of the plurality of air conditioners, and the state of the preset element is that the air conditioner flow rates for each of the plurality of air conditioners are all below a predetermined value.

[0008] Furthermore, in order to solve the above-mentioned problems, an air conditioning system according to the present invention includes a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, piping connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, a detection unit for detecting whether the state of an element related to the operation of the air conditioners matches the state of a preset element, and a chilled or hot water pump for controlling the chilled or hot water flow rate of the chilled or hot water pump so that the differential pressure between the upstream and downstream sides of the chilled or hot water pump is the differential pressure required for the flow of the total air conditioner flow rate required by a system including at least each of the air conditioners and the piping. The air conditioner includes a setting unit that sets the pump output, and a control unit that controls the chilled / hot water pump with the chilled / hot water pump output set by the setting unit, and when the detection unit detects that the state of the air conditioner elements does not match the state of the preset elements, the setting unit sets the chilled / hot water pump output to a first output, and when the detection unit detects that the state of the air conditioner elements matches the state of the preset elements, the setting unit sets the chilled / hot water pump output to a second output, and the detection unit includes a power detection unit that detects the power usage of electrical equipment in a room where multiple air conditioners are installed, and the state of the preset elements is that the power usage of the electrical equipment in the room where multiple air conditioners are installed is below a predetermined value. In order to solve the above problems, an air conditioning system according to the present invention includes a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, piping connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, a detection unit for detecting whether the state of an element related to the operation of the air conditioners matches the state of a preset element, and a chilled or hot water pump that controls the pressure difference between the upstream and downstream sides of the chilled or hot water pump to be a pressure difference required for the flow of a total air conditioner flow rate required by a system including at least each of the air conditioners and the piping. The air conditioner is provided with a setting unit that sets the chilled / hot water pump output of the pump, and a control unit that controls the chilled / hot water pump with the chilled / hot water pump output set by the setting unit, and when the detection unit detects that the state of the air conditioner elements does not match the state of the preset elements, the setting unit sets the chilled / hot water pump output to a first output, and when the detection unit detects that the state of the air conditioner elements matches the state of the preset elements, the setting unit sets the chilled / hot water pump output to a second output, and the multiple air conditioners are all air conditioners into which outside air is introduced, and the detection unit includes an outside air specific enthalpy detection unit, and the preset state of the elements is when the outside air specific enthalpy of the outside air is equal to or less than a predetermined value. In order to solve the above problems, an air conditioning system according to the present invention includes a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, piping connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, a detection unit for detecting whether the state of an element related to the operation of the air conditioners matches the state of a preset element, and a cooling / cooling unit for controlling the chilled or hot water pump so that the differential pressure between the upstream and downstream sides of the chilled or hot water pump becomes the differential pressure required for the flow of the total air conditioner flow required by a system including at least each of the air conditioners and the piping. The system includes a setting unit that sets the hot water pump output and a control unit that controls the cold / hot water pump with the cold / hot water pump output set by the setting unit, and when the detection unit detects that the state of the air conditioner elements does not match the state of the preset elements, the setting unit sets the cold / hot water pump output to a first output, and when the detection unit detects that the state of the air conditioner elements matches the state of the preset elements, the setting unit sets the cold / hot water pump output to a second output, and the detection unit includes an air conditioning load detection unit that detects air temperature, humidity, and air volume and is provided at the entrances and exits of multiple air conditioners, and the state of the preset elements is when the product of the air temperature, humidity, and air volume at the entrances and exits of multiple air conditioners is less than a predetermined value.

[0009] In order to solve the above-mentioned problems, a control method for an air conditioning system according to the present invention includes a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, and piping sequentially connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, the control method comprising the steps of: detecting by a detection unit whether a state of an element related to operation of the air conditioners conforms to a state of a preset element; if the state of the element related to operation of the air conditioners does not conform to the state of the preset element, a setting unit setting the chilled or hot water pump output to a first output; if the state of the element related to operation of the air conditioners conforms to the state of the preset element, a setting unit setting the chilled or hot water pump output to a second output; and controlling the chilled or hot water pump with the chilled or hot water pump output. The detection unit includes an air conditioner flow rate detection unit that measures the air conditioner flow rate for each of the plurality of air conditioners, and the state of the preset element is that the air conditioner flow rates for each of the plurality of air conditioners are all below a predetermined value. In order to solve the above-mentioned problems, a control method for an air conditioning system according to the present invention is a control method for an air conditioning system including a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, and piping connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, the control method comprising the steps of: detecting, by a detection unit, whether a state of an element relating to the operation of the air conditioners conforms to a preset element state; The method includes a step of setting the chilled / hot water pump output of the chilled / hot water pump to a first output if the state of the element related to the operation of the air conditioner does not match the state of the preset element, and a step of setting the chilled / hot water pump output to a second output if the state of the element related to the operation of the air conditioner matches the state of the preset element, and a step of controlling the chilled / hot water pump with the chilled / hot water pump output, and the detection unit includes a power detection unit that detects the power usage of electrical equipment in a room where multiple air conditioners are installed, and the state of the preset element is that the power usage of electrical equipment in the room where multiple air conditioners are installed is equal to or less than a predetermined value. In order to solve the above-mentioned problems, a control method for an air conditioning system according to the present invention includes a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, and piping connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, the control method comprising the steps of: detecting, by a detection unit, whether a state of an element relating to the operation of the air conditioners conforms to a state of a preset element; The method includes a step in which, if the state of the element does not match the preset element state, a setting unit sets the chilled / hot water pump output of the chilled / hot water pump to a first output, and a step in which, if the state of the element related to the operation of the air conditioner matches the preset element state, the setting unit sets the chilled / hot water pump output to a second output and controls the chilled / hot water pump with the chilled / hot water pump output, wherein the plurality of air conditioners are all air conditioners into which outside air is introduced, the detection unit includes an outside air specific enthalpy detection unit, and the preset element state is when the outside air specific enthalpy of the outside air is equal to or less than a predetermined value. In order to solve the above-mentioned problems, a control method for an air conditioning system according to the present invention is a control method for an air conditioning system including a heat source for heating or cooling chilled or hot water, a plurality of air conditioners through which chilled or hot water flows, a plurality of control valves connected to each of the air conditioners and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners, a chilled or hot water pump for supplying chilled or hot water to each of the air conditioners, and piping connecting the heat source, the chilled or hot water pump, each of the air conditioners, and each of the control valves, the control method comprising the steps of: detecting, by a detection unit, whether a state of an element relating to the operation of the air conditioners conforms to a preset state of an element; The method includes a step of setting the chilled / hot water pump output of the chilled / hot water pump to a first output when the state of the element related to the operation of the air conditioner does not match the state of the preset element, a step of setting the chilled / hot water pump output to a second output when the state of the element related to the operation of the air conditioner matches the state of the preset element, and a step of controlling the chilled / hot water pump with the chilled / hot water pump output, and the detection unit includes an air conditioning load detection unit that is provided at the inlets and outlets of the plurality of air conditioners and detects air temperature, humidity, and air volume, and the state of the preset element is when the product of the air temperature, humidity, and air volume at the inlets and outlets of the plurality of air conditioners is equal to or less than a predetermined value. . [Effects of the Invention]

[0010] The air conditioning system and control method for an air conditioning system of this invention include a detection unit that detects that the operating conditions of the air conditioner conform to the state of a predetermined element, a setting unit that sets the output of the chilled / hot water pump so that the differential pressure between the upstream and downstream sides of the chilled / hot water pump becomes the differential pressure necessary for the circulation of the total air conditioner flow rate required by a system including at least each air conditioner and piping, a control unit that controls the chilled / hot water pump with the output of the chilled / hot water pump set by the setting unit, and when the detection unit detects that the state of the air conditioner element does not conform to the state of the predetermined element, the setting unit sets the chilled / hot water pump output to a first output, and when the detection unit detects that the operating conditions of the air conditioner conform to the predetermined operating conditions, the setting unit sets the chilled / hot water pump output to a second output, thereby reducing the amount of energy consumed in the air conditioning system and control method thereof. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of an air conditioning system according to a first embodiment of the present invention. [Figure 2] 2 is a first model for examining the differential pressure for variable flow control in the air conditioning system shown in FIG. 1. [Figure 3] 2 is a second model for examining the differential pressure for variable flow control in the air conditioning system shown in FIG. 1. [Figure 4] 2 is a graph showing the relationship between the flow rate ratio, the differential pressure ratio, and the resistance ratio in the air conditioning system shown in FIG. [Figure 5] 2 is a graph showing the relationship between the flow rate ratio and the power in the air conditioning system shown in FIG. [Figure 6] 10 is a graph showing an example of the relationship between the amount of hot and cold water per coil tube circulating in an air conditioner coil and the water-side resistance per path. [Figure 7] 10 is a graph showing an example of the relationship between the water velocity of cold and hot water in a coil tube flowing through an air conditioner coil and tube resistance. [Figure 8] 10 is a graph showing an example of the relationship between the amount of hot and cold water per coil tube and the thermal transmittance per frontal area. [Figure 9] 2 is a graph showing an example of an air conditioner coil device characteristic in the air conditioning system shown in FIG. 1. [Figure 10] 10 is a graph showing an enlarged portion of the graph shown in FIG. 9 where the heat transfer coefficient ratio is 90% to 100%. [Figure 11] 5 is a graph showing the relationship between the flow rate ratio, the differential pressure ratio, and the resistance ratio when the resistance ratio of air conditioner 40, which provides the greatest circulation resistance among the air conditioners, is reduced to 40% for the air conditioning system shown in FIG. [Figure 12] 6 is a graph showing the relationship between the flow rate ratio, the differential pressure ratio, and the resistance ratio when the resistance ratio of air conditioner 40, which provides the greatest circulation resistance among the air conditioners, is reduced to 40% for the air conditioning system shown in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Air conditioning system configuration) Embodiment 1 A first embodiment of the present invention will be described below with reference to FIGS. 1 to 12 of the accompanying drawings. FIG. 1 is a schematic diagram of an air conditioning system according to the first embodiment. The air conditioning system 1, installed in a facility or building (not shown), includes a heat source 60, a chilled / hot water pump 20 for circulating chilled / hot water flowing out of the heat source 60, and piping 30 in which the chilled / hot water pump 20 is installed and through which the chilled / hot water circulates. The piping 30 includes an inlet piping 31 and an outlet piping 32. The inlet piping 31 has branches and is connected to the inlets of a plurality of air conditioners 40 installed, for example, on each floor or in each room of the building. The heat source 60 may be any heat source including, for example, a heat pump chiller, a chiller / heater, a turbo chiller, or a boiler. Alternatively, a heat exchanger or a receiving unit for chilled / hot water supplied from outside the building may be used.

[0013] The air conditioner 40 has an air intake 41 that takes in ambient air, a fan 42, an air conditioning coil 43, and an outlet 44 that blows out cool or warm air. The air intake 41 has an air intake sensor 46 that detects the temperature, humidity, and air volume of the air being taken in. The outlet 44 has an outlet sensor 47 that detects the air temperature, humidity, and air volume of the air being blown out. The air intake sensor 46 and the outlet sensor 47 make up an air conditioning load detection unit.

[0014] An inlet pipe 31 is connected to the inlet side of the air conditioner coil 43, and chilled or hot water flows in from the inlet pipe 31. An outlet pipe 32 is connected to the outlet side of each air conditioner coil 43. The outlet pipes 32 join and are connected to a heat source 60, and the chilled or hot water flowing out of the air conditioner coil 43 joins via the outlet pipe 32 and then flows into the heat source 60. A control valve 50 is provided in the outlet pipe 32 for each air conditioner 40 to control the chilled or hot water flow rate of the air conditioner coil 43 of each air conditioner 40. The opening of each control valve 50 is controlled by an air conditioner control unit 45 provided in each air conditioner 40. A detector 80 is provided at the junction of the outlet pipe 32 to measure the chilled or hot water flow rate when the chilled or hot water that has flowed through the air conditioner coil 43 of each air conditioner 40 flows into the heat source 60 after joining. The chilled / hot water pump 20, piping 30, inlet piping 31, outlet piping 32, air conditioner coil 43, control valve 50, and heat source 60 constitute the chilled / hot water system of the air conditioning system 1. Each control valve 50 has a flow rate detection unit (not shown) that measures the internal pressure difference of the control valve 50 to detect the flow rate of chilled / hot water flowing through the control valve 50. In other words, the control valve 50 constitutes the air conditioner flow rate detection unit. The control unit 70 can obtain the detection result of the flow rate detection unit via the electrically connected air conditioner control unit 45.

[0015] An inverter 21 that controls the chilled / hot water pump 20 is connected to the inverter 21. A control unit 70 that controls the entire air conditioning system 1 is connected to the inverter 21. The control unit 70 may be part of, for example, a known building energy management system (BEMS). The control unit 70 is connected to an outdoor air specific enthalpy detection unit 81 that includes an outdoor temperature and humidity detection unit and the like that detects the outdoor air specific enthalpy of the outdoor air, an air conditioning load detection unit 82 that is connected to the inlet sensor 46 and the outlet sensor 47 of each air conditioner 40 and detects the air conditioning load of each air conditioner 40, a power detection unit 83 that detects the power consumption of electrical equipment used in the air conditioning range of the air conditioner in the building in which each air conditioner 40 is installed, a setting unit 90 that sets the output of the chilled / hot water pump 20, and an air conditioner control unit 45. The setting unit 90 stores a setting table for the flow rate and required differential pressure of the piping flow path that supplies chilled or hot water to each air conditioner 40 of the chilled or hot water pump 20. Based on this setting table, the pump rotation speed for the target pump flow rate and the control value of the inverter 21 for controlling the chilled or hot water pump 20 at that pump rotation speed are set. Note that, if the differential pressure of the terminal air conditioner 40 is detected, a setting table may not be provided, and only the terminal differential pressure may be set. The detector 80, the outdoor air specific enthalpy detection unit 81, which includes an outdoor temperature and humidity detection unit, the air conditioning load detection unit 82, and the power detection unit 83 constitute a condition detection unit. The control unit 70 and the air conditioner control unit 45 constitute a control unit. The pump rotation speed of the chilled or hot water pump 20 correlates with the output of the chilled or hot water pump 20. For example, the cube of the pump rotation speed of the chilled or hot water pump 20 divided by the efficiency reduction of the component equipment corresponds to the output of the chilled or hot water pump 20.

[0016] When the air conditioning system 1 is operating, the chilled / hot water pump 20 circulates the chilled / hot water flowing out from the heat source 60 to each air conditioner 40, and the chilled / hot water that has flowed through each air conditioner 40 flows through the control valve 50 and into the heat source 60, causing the chilled / hot water to circulate through the chilled / hot water system. At this time, the differential pressure at which the chilled / hot water pump 20 circulates the chilled / hot water is controlled by the control unit 70 controlling the inverter 21 based on the pump output set by the setting unit 90 and the control value of the inverter 21.

[0017] (Study of the required differential pressure for variable flow control in air conditioning systems) FIG. 2 is a model diagram for examining the required differential pressure for variable flow control in the air conditioning system 1 shown in FIG. Here, the differential pressure in this invention refers to the difference in chilled / hot water pressure between the upstream and downstream sides of a certain section of the chilled / hot water flow path, including the pipe 30, the inlet pipe 31, and the outlet pipe 32. To circulate an appropriate amount of chilled / hot water to each air conditioner 40, the chilled / hot water pump differential pressure, which is the differential pressure between the upstream and downstream sides of the chilled / hot water pump 20, must be equal to or greater than the flow path resistance, which is the resistance in the chilled / hot water system throughout the entire chilled / hot water flow path of the air conditioning system 1. Herein, the flow path resistance is the sum of the piping resistance, which is the resistance of the pipe 30, the inlet pipe 31, and the outlet pipe 32, and the resistance of the air conditioner coil (not shown) and each control valve 50 of each air conditioner 40. Hereinafter, the sum of the resistance of the air conditioner coil of each air conditioner 40 and the resistance of each control valve 50 for each air conditioner 40 is referred to as the air conditioner resistance. The pressure difference for circulating the hot and cold water against the air conditioner resistance will be referred to as the air conditioner pressure difference hereinafter.

[0018] In the model shown in FIG. 2, ten air conditioners 40 are connected in parallel to a chilled / hot water pump 20. A control valve 50 is provided for each air conditioner 40. The air conditioner flow rate ratio, which is the chilled / hot water flow rate that should be circulated through each air conditioner 40 to the design maximum air conditioner flow rate, is shown in the air conditioner 40 as a numerical value excluding percentages. In the following explanation, when a numerical value is shown that is not limited to the air conditioner flow rate ratio, the numerical value is shown as including an approximate number. In the model shown in FIG. 2, each air conditioner 40 is operating at the design maximum value, so the air conditioner flow rate ratio of each air conditioner 40 is 100%, and the air conditioner flow rate ratios of all the air conditioners 40 are uniform. In this model, the outlet side piping 32 connected to each air conditioner 40 is divided into m1 to m 10 The inlet pipes 31 connected to the air conditioners 40 are designated by n1 to n 10 The pipe 30 on which the hot and cold water pump 20 is provided is indicated by the symbol m0.

[0019] In this model, the pipe length between m0 and m1, the pipe length between m1 and m2...m9 to m 10 The pipe lengths between m0 and n1 are the same, and the pipe lengths between n1 and n2 are the same... 10 The lengths of the piping between the air conditioners 40 and the piping connected thereto are the same. The side closer to the chilled / hot water pump 20 is referred to as the front side, and the side farther from the chilled / hot water pump 20 is referred to as the end side.

[0020] The chilled / hot water pump differential pressure, which is the pressure difference between the upstream and downstream sides of the chilled / hot water pump 20 in the piping 30, is indicated by the symbol Pt. The air conditioner resistance is indicated by a shaded arrow Ra, and the control valve resistance of the control valve 50 is indicated by a plain arrow Rc. Furthermore, the round-trip resistance of the inlet side piping 31 and the outlet side piping 32, i.e., the piping resistance, is indicated by Rp, and the maximum value of the air conditioner resistance in the air conditioning system 1 is indicated by Rm. The magnitudes of the pressure difference Pt, air conditioner resistance Ra, control valve resistance Rc, piping resistance Rp, and maximum value Rm are each shown as corresponding to the horizontal length in FIG. 2.

[0021] The model shown in Fig. 3 differs from the model shown in Fig. 2 in that not all air conditioners 40 are operating at their maximum design value. Specifically, this is a model diagram for consideration when the chilled / hot water flow rate ratio of the entire air conditioning system 1b is 50%, and the air conditioner flow rate ratios of the first to fourth air conditioners 40 counting from the end are 100%, the fifth to eighth air conditioners 40 counting from the end are 20%, and the ninth and tenth air conditioners 40 are 10%.

[0022] Next, the piping resistance of the entire air conditioning system is considered in the study model of air conditioning system 1b shown in Figure 3. In this model, the piping resistance Rp of the entire air conditioning system 1b is 38% of the piping resistance Rp of the entire air conditioning system 1.

[0023] Next, we consider the maximum design value of the air conditioner resistance of the air conditioning system in the study model shown in Figure 3. In air conditioning system 1b, the maximum air conditioner resistance Rm is the air conditioner resistance of the first to fourth air conditioners 40 from the end, each with an air conditioner flow ratio of 100%. Since the air conditioner flow rate of each air conditioner 40 fluctuates independently regardless of the chilled or hot water flow rate of the entire air conditioning system, if there is an air conditioner 40 among the air conditioners 40 that is operating at the maximum design value and has an air conditioner flow ratio of 100%, as in air conditioning system 1b shown in Figure 3, fluctuations in air conditioner resistance have a greater impact on the resistance of the chilled or hot water flow path of the entire air conditioning system than fluctuations in piping resistance.

[0024] Generally, when an air conditioning system includes an air conditioner that may operate at its maximum design value, it is unclear where in the system the air conditioner operating at its maximum design value will occur. The air conditioner 40 with the highest air conditioner resistance may be located either at the front or at the end. As shown in the model study in FIG. 3 , when the air conditioner 40 with the highest air conditioner resistance is located at the end, the greatest resistance occurs in the chilled / hot water flow path. Therefore, in conventional air conditioning systems, control must be performed to achieve the same differential pressure as when all air conditioners 40 are operating at their maximum design value. Note that the model study in FIG. 3 is a model in which the air conditioner 40 with the highest air conditioner resistance is located at the end of the air conditioning system 1. However, in this air conditioning system 1, the air conditioner 40 with the highest air conditioner resistance may be located elsewhere.

[0025] (Variable flow rate control method in air conditioning systems) Next, a method of variable flow rate control of chilled / hot water in the air conditioning system 1 shown in Figures 1 and 2 will be described. Figure 4 is a graph showing the relationship between the flow rate ratio, differential pressure ratio, and resistance ratio in the case where the air conditioner flow rate ratios of all air conditioners 40 fluctuate evenly and there is no uneven distribution, with the horizontal axis representing the flow rate ratio to the maximum flow rate of chilled / hot water, and the vertical axis representing the differential pressure ratio of the chilled / hot water pump differential pressure of chilled / hot water pump 20 to the maximum differential pressure, and the resistance ratio of the total resistance to the maximum value of the total resistance of the chilled / hot water flow path in the air conditioning system 1. Figure 5 is a graph showing the relationship between the flow rate ratio and power in the air conditioning system 1, with the horizontal axis representing the flow rate ratio to the maximum flow rate of chilled / hot water, and the vertical axis representing the power of chilled / hot water pump 20.

[0026] The variable flow rate control methods for chilled / hot water in the air conditioning system 1 (see FIGS. 1 and 2) can include minimum differential pressure control by monitoring all control valves, constant differential pressure control, estimated differential pressure control, and terminal differential pressure control. In this first embodiment, we consider a case where the air conditioner flow rate ratios of all air conditioners 40 in the air conditioning system 1 fluctuate evenly and are not unevenly distributed. In FIG. 4, the curve labeled A shows the relationship between the chilled / hot water flow rate ratio and the resistance ratio of the total resistance in the case of minimum differential pressure control by monitoring the opening degrees of all control valves. In FIG. 5, the curve labeled A shows the relationship between the chilled / hot water flow rate ratio and the power of the chilled / hot water pump 20 in the case of minimum differential pressure control by monitoring the opening degrees of all control valves. The minimum differential pressure control by monitoring all control valves is a control method in which the operating state of the corresponding air conditioner 40 is detected from the control information of the control valves 50 of each air conditioner 40 by the air conditioner control unit 45, and the detected state is fed back to the control of the chilled / hot water pump 20 by the control unit 70. As will be explained in detail later, minimum differential pressure control by monitoring all control valves can be used as a method of controlling the variable flow rate of chilled and hot water in the air conditioning system 1 to achieve the minimum differential pressure that satisfies the differential pressure of the air conditioner that requires the most differential pressure for the air conditioner.

[0027] If the flow rate ratios of all air conditioners fluctuate evenly and there is no uneven distribution, when the air conditioner flow rate ratio decreases from 100%, the resistance ratio of the chilled / hot water flow path of the air conditioning system 1 and the differential pressure ratio of the differential pressure Pt required to circulate the chilled / hot water against this resistance decrease, as shown by the curve A in Fig. 4. Furthermore, when the air conditioner flow rate ratio of each air conditioner 40 decreases, the power of the chilled / hot water pump 20 for circulating the chilled / hot water decreases, as shown by the curve A in Fig. 5.

[0028] Constant differential pressure control is a control method in which the differential pressure Pt is kept at a constant maximum value regardless of the flow rate ratio of hot and cold water. Therefore, as shown by the straight line B in Figure 4, the flow rate ratio and differential pressure ratio are constant, and the difference between the differential pressure ratio shown by the straight line B and the differential pressure ratio shown by the curve A is the excess differential pressure ratio relative to the flow rate ratio shown on the horizontal axis. Furthermore, the relationship between the flow rate ratio and power in constant differential pressure control is as shown by the straight line B in Figure 5.

[0029] Estimated differential pressure control is a control method that, in the model shown in FIG. 2, pre-sets the differential pressure Pt required when the air conditioner flow rate ratio of the first air conditioner 40 counting from the end, where the required differential pressure is greatest in the flow path, is set to 100%, so that the differential pressure is not insufficient when 100% of the design maximum water volume is required for any one of the air conditioners 40. In the example shown in FIG. 4, the differential pressure ratio for the differential pressure Pt is 30%. Note that this differential pressure ratio of 30% is an example, and other values ​​for the differential pressure ratio are possible. This differential pressure ratio of 30% is set as the differential pressure ratio when the flow rate ratio is 0%, and control is performed using a setting table that estimates the differential pressure relative to the flow rate ratio along the line C that connects the differential pressure ratio of 100% when the flow rate ratio is 100% and the differential pressure ratio of 30% when the flow rate ratio is 0%. Note that this line may be set as a quadratic curve so that the piping resistance decreases quadratically with the flow rate. The relationship between the flow rate ratio and power in this estimated differential pressure control is shown by the curve C in Fig. 5. The difference between the differential pressure ratio shown by the straight line C in Fig. 4 and the differential pressure ratio shown by the curve A and the differential pressure ratio shown by the quadratic curve D is the excess differential pressure ratio for the flow rate ratio shown on the horizontal axis. Since the estimated differential pressure control reduces the excess differential pressure more than the constant differential pressure control, it is possible to reduce the power of the chilled / hot water pump 20, as shown by the straight line C in Fig. 5.

[0030] Constant terminal differential pressure control is a control method for controlling the terminal differential pressure measured in the terminal air conditioner 40 to a preset terminal differential pressure. In this constant terminal differential pressure control, as shown by the curve D in FIG. 4, the control unit 70 controls the chilled / hot water pump 20 to achieve the differential pressure ratio Pe even when the flow rate ratio is 0%. This is because, regardless of which air conditioner 40 in the air conditioning system 1 needs to operate at its maximum flow rate, the control is performed so that the necessary chilled / hot water flow rate can be circulated accordingly. As a result, as shown by the curve D in FIGS. 4 and 5, the differential pressure Pt relative to the flow rate ratio can be lowered compared to the differential pressure control shown by the curve C, thereby reducing the power required for the chilled / hot water pump 20. FIG. 4 shows a case where the flow rate ratios of all air conditioners 40 fluctuate evenly and there is no unevenness. In other cases, the curve D fluctuates due to unevenness, but the curve D can be tracked because the terminal differential pressure control measures the actual terminal differential pressure.

[0031] In the minimum differential pressure control by monitoring all control valves, indicated by symbol A, the relationship between the chilled / hot water flow rate ratio and the chilled / hot water pump differential pressure can be reduced even more by further reducing the excess differential pressure Pt and reducing the power consumption of the chilled / hot water pump 20 than in the constant differential pressure control, estimated differential pressure control, and constant terminal differential pressure control. Therefore, minimum differential pressure control by monitoring all control valves can be said to be ideal control. In this minimum differential pressure control by monitoring all control valves, the control unit 70 receives control valve 50 position control information from the air conditioner control unit 45 corresponding to each air conditioner 40. If the control unit 70 detects that the control valve 50 is set to a low position, it determines that the corresponding air conditioner 40's differential pressure is sufficient, and controls the control unit 70 to lower the chilled / hot water pump differential pressure until a valve is set to its maximum or near-maximum position. Therefore, inputting the control valve 50 position control information from the air conditioner control unit 45 into the control unit 70 poses the problems of increased wiring costs between the control unit 70 and the air conditioner control unit 45 and increased man-hours required for analog / digital data conversion.

[0032] Next, we will consider the relationship between the chilled / hot water flow rate and resistance in the air conditioner coil 43 of the air conditioner 40 shown in FIG. 1. To supply the required flow rate of chilled / hot water to the air conditioner coil 43, a differential pressure greater than the resistance to the chilled / hot water in the air conditioner 40 must be applied to the air conditioner coil 43. FIG. 6 is a graph showing an example of the relationship between the amount of chilled / hot water per coil tube flowing through the air conditioner coil 43 and the water-side resistance per pass. The water-side resistance per pass is proportional to approximately the square of the amount of chilled / hot water. FIG. 7 is a graph showing an example of the relationship between the water velocity of chilled / hot water in the coil tube flowing through the air conditioner coil 43 and the tube resistance. The tube resistance is proportional to approximately the square of the water velocity of the chilled / hot water in the coil tube. Therefore, it can be seen that the required differential pressure in the air conditioner coil 43 is proportional to approximately the square of the flow rate ratio of chilled / hot water.

[0033] Next, we will consider the relationship between the flow rate of chilled or hot water in the air conditioner coil 43 of the air conditioner 40 shown in Figure 1 and the cooling capacity of the air passing through the air conditioner coil 43. Figure 8 is a graph showing an example of the relationship between the amount of chilled or hot water per coil tube and the thermal transmittance per frontal area. The solid curve E in Figure 8 shows the case where the surface velocity of the air passing through the air conditioner coil is 2.5 m / s, and the dashed curve F shows the case where the surface velocity of the chilled or hot water is 2.0 m / s. For example, as shown in curve F, when the surface velocity of the chilled or hot water is 2.0 m / s and the flow rate of the air conditioner coil is 24 ml / min, the thermal transmittance is 810 W / m 2 (FA)·K· row, and when the air conditioner coil flow rate is 14.4 l / min, which is 60% of 24 ml / min, the thermal transmittance is 810 W / m 2 760W / m 2 It is the (FA)·K· sequence.

[0034] FIG. 9 is a graph showing an example of the characteristics of an air conditioner coil used in the air conditioner 40 (see FIG. 1). This graph shows the heat transfer coefficients for each water velocity and surface velocity of chilled and hot water in the air conditioner coil characteristics, replaced with the heat transfer coefficients relative to the resistance ratio of the air conditioner coil. The resistance ratio shown on the horizontal axis can also be said to be the required differential pressure ratio required for the maximum differential pressure between the inlet and outlet sides of the air conditioner 40 when a certain heat transfer coefficient ratio is achieved. The heat transfer coefficient ratio of the air conditioner coil shown on the vertical axis corresponds to the ratio of the cooling capacity to the maximum cooling capacity of the air conditioner 40. FIG. 10 is a graph showing an enlarged portion of the graph shown in FIG. 9 with a heat transfer coefficient ratio of 90% to 100%. Referring to FIG. 10, the required resistance ratio of the air conditioner 40 is 20% when the heat transfer coefficient ratio of the air conditioner coil is 90%, and the required resistance ratio of the air conditioner 40 is 40% when the heat transfer coefficient ratio of the air conditioner coil is 95%. That is, when the required cooling capacity of the air conditioner coil of the air conditioner 40 is 90% or less of the maximum capacity, it is possible to reduce the resistance ratio of the air conditioner 40 to 20% or less, and when it is 95% or less of the maximum capacity, it is possible to reduce the resistance ratio of the air conditioner 40 to 40% or less. Note that in the air conditioner coil of the air conditioner 40 shown in Fig. 9, when it is 90% or less of the maximum capacity, it is possible to reduce the resistance ratio of the air conditioner 40 to 20% or less, and when it is 95% or less of the maximum capacity, it is possible to reduce the resistance ratio of the air conditioner 40 to 40% or less. This is an example of the general characteristics of an air conditioner coil that uses chilled or hot water to cool and heat the air side, and the air conditioner coil may have different characteristics.

[0035] Next, as examined with reference to Figures 9 and 10, the relationship between the flow rate ratio, the differential pressure ratio, and the resistance ratio will be examined when, in the air conditioning system 1 (see Figure 1), the required cooling capacity of the air conditioner coil of the air conditioner 40 that causes the greatest circulation resistance among all the air conditioners 40 (hereinafter referred to as the air conditioner with the greatest resistance) is 95% or less of the maximum capacity, and the resistance ratio of the air conditioner 40 with the greatest resistance is reduced to 40% for the air conditioning system 1 examined with reference to Figure 4 above. Figure 11 is a graph showing the relationship between the flow rate ratio, the differential pressure ratio, and the resistance ratio for the air conditioning system shown in Figure 4 when the resistance ratio of the air conditioner 40 that causes the greatest circulation resistance is reduced to 40%.

[0036] As shown in Figure 11, when minimum differential pressure control is used by monitoring all control valves, the relationship between the flow rate ratio, differential pressure ratio, and resistance ratio is shown by the curve labeled A when the resistance ratio of the air conditioner 40 with the highest resistance (see Figure 2) is 100%, and the dashed curve labeled A1 when the resistance ratio of the air conditioner 40 with the highest resistance is reduced to 40%. Furthermore, when constant differential pressure control is used, the relationship between the flow rate ratio, differential pressure ratio, and resistance ratio is shown by the straight line labeled B when the resistance ratio of the air conditioner 40 with the highest resistance is 100%, and the dashed straight line labeled B1 when the resistance ratio of the air conditioner 40 with the highest resistance is reduced to 40%. Furthermore, when estimated differential pressure control is used, the relationship between the flow rate ratio, differential pressure ratio, and resistance ratio is shown by the straight line labeled C when the resistance ratio of the air conditioner 40 with the highest resistance is 100%, and the dashed straight line labeled C1 when the resistance ratio of the air conditioner 40 with the highest resistance is reduced to 40%. Furthermore, with regard to the relationship between the flow rate ratio, differential pressure ratio, and resistance ratio when using constant terminal differential pressure control, the case where the resistance ratio of the air conditioner 40 with the greatest resistance is 100% is shown by the curve labeled D, and the case where the resistance ratio of the air conditioner 40 with the greatest resistance is reduced to 40% is shown by the dashed curve labeled D1. By reducing the resistance ratio of the air conditioner 40 with the greatest resistance to 40%, the differential pressure Pt of the air conditioning system 1 is reduced as shown by arrows A2, B2, C2, and D2 in all cases of minimum differential pressure control with full control valve monitoring, constant differential pressure control, estimated differential pressure control, and constant terminal differential pressure control.

[0037] FIG. 12 is a graph showing the relationship between the flow rate ratio and the power ratio when the resistance ratio of the air conditioner 40, which provides the maximum circulation resistance, is reduced to 40% for the air conditioning system shown in FIG. When the resistance ratio of the air conditioner 40 with the maximum resistance (see FIG. 2) is reduced to 40%, the curve A1 showing the relationship between the flow rate ratio and power when minimum differential pressure control with full control valve monitoring is used, the straight line B1 showing the relationship between the flow rate ratio and power when constant differential pressure control is used, the curve C1 showing the relationship between the flow rate ratio and power when estimated differential pressure control is used, and the curve D1 showing the relationship between the flow rate ratio and power when constant terminal differential pressure control are used, are compared with the curve A, the straight line B, the curve C, and the curve D shown in FIG. 5 when the resistance ratio of the air conditioner 40 with the maximum resistance is 100%, as shown by arrows A2, B2, C2, and D2, the power of the chilled / hot water pump 20 is reduced in all cases of minimum differential pressure control with full control valve monitoring, constant differential pressure control, estimated differential pressure control, and constant terminal differential pressure control.

[0038] In other words, by reducing the resistance ratio of the air conditioner 40 with the highest resistance (see Figure 2) to 40%, the differential pressure Pt of the air conditioning system 1 and the power of the cold and hot water pump 20 are reduced, thereby reducing the amount of energy consumed by the air conditioning system 1 as a whole.

[0039] (Consideration when air conditioner load is high) Next, we will consider the frequency of occurrence of cases in the air conditioning system 1 shown in Fig. 1 where the air conditioning load, which is the sum of the loads on the air conditioners 40, increases due to an increase in the cooling capacity required of each air conditioner 40. When the cooling capacity required of the air conditioners 40 installed in a building increases, the air conditioning load of the air conditioners 40 increases, and the air conditioning resistance of the air conditioners 40 increases. As shown in Figs. 2 and 3 and described above, an increase in the air conditioning resistance of the air conditioner 40 has a significant impact on the increase in the resistance of the air conditioning system 1 as a whole.

[0040] However, depending on the building in which the air conditioning system 1 is installed, there may be a low possibility that the air conditioners 40 will be operated when the air conditioner load factor is close to the design maximum. For example, if the air conditioner load factor of the air conditioners 40 installed in the building is 90% or less of the design maximum, it is possible to reduce the resistance ratio of the air conditioners 40 to 20% or less as shown in FIG. 11 as described above. If the air conditioner load factor is 95% or less of the design maximum, it is possible to reduce the resistance ratio of the air conditioners 40 to 40% or less. In particular, if it is confirmed that the air conditioner loads of all the air conditioners 40 are always 90% or 95% or less, it is considered that the capacity of the air conditioners 40 will not be insufficient even if the differential pressure ratio of the terminal differential pressure in the estimated differential pressure control and the constant terminal differential pressure control is set to 20% or 40%.

[0041] (Method for detecting air conditioner load) Next, a method for detecting the air conditioning load of each air conditioner 40 in the air conditioning system 1 installed in a building will be considered. The following method can be used to detect the air conditioning load of each air conditioner 40 in the air conditioning system 1.

[0042] 1 performs cooling operation, the air conditioning load of each air conditioner 40 is assumed to be 100% of the design maximum value at the start of operation, and the setting unit 90 sets the output of the chilled / hot water pump 20 corresponding to this air conditioning load. Then, the control unit 70 controls the chilled / hot water pump 20 based on the first output of the chilled / hot water pump 20 set by the control unit 90.

[0043] During cooling operation of each air conditioner 40, a flow rate detector (not shown) of the control valve 50 detects the flow rate of chilled or hot water flowing through the control valve 50, allowing the control unit 70 to detect the air conditioner flow rate of each air conditioner 40. If the air conditioner flow rate of each air conditioner 40 is equal to or less than a preset threshold, the control unit 70 can confirm that the air conditioner load is equal to or less than a predetermined ratio of the designed maximum air conditioner load. Next, the control unit 90 sets the second output of the chilled or hot water pump 20 so that the differential pressure required for the total air conditioner flow rate required by the system including at least each air conditioner 40, the piping 30, the inlet piping 31, and the outlet piping 32 is achieved, and so that the differential pressure ratio of the maximum air conditioner differential pressure is equal to or less than the predetermined ratio. Next, the control unit 70 controls the chilled or hot water pump 20 based on the second output of the chilled or hot water pump 20 set by the setting unit 90. This reduces the differential pressure ratio of the maximum air conditioner differential pressure of the air conditioning system 1, thereby reducing the amount of energy consumed by the chilled or hot water pump 20.

[0044] As described above, the air conditioning system 1 according to the first embodiment includes a heat source 60 for heating or cooling chilled or hot water, a plurality of air conditioners 40 through which chilled or hot water flows, a plurality of control valves 50 connected to each of the air conditioners 40 and controlling the flow rate of the chilled or hot water flowing through each of the air conditioners 40, a chilled or hot water pump 20 for supplying chilled or hot water to each of the air conditioners 40, piping 30, inlet piping 31 and outlet piping 32 that sequentially connect the heat source 60, the chilled or hot water pump 20, each of the air conditioners 40, and each of the control valves 50, a detection unit that detects whether the state of an element related to the operation of the air conditioner 40 conforms to the state of a preset element, and a pressure difference between the upstream side and downstream side of the chilled or hot water pump 20 and at least each of the air conditioners 40 and the piping 30. The air conditioning system 1 includes a setting unit 90 that sets the output of the chilled / hot water pump so as to achieve the differential pressure required for the circulation of the total air conditioner flow rate required by the system, and a control unit 70 that controls the chilled / hot water pump 20 with the output of the chilled / hot water pump 20 set by the setting unit 90. When the detection unit detects that the state of the elements of the air conditioner 40 does not match the state of the preset elements, the setting unit 90 sets the output of the chilled / hot water pump 20 to a first output, and when the detection unit detects that the state of the elements of the air conditioner 40 matches the state of the preset elements, the setting unit 90 sets the output of the chilled / hot water pump 20 to a second output, thereby providing an air conditioning system 1 that consumes a reduced amount of energy.

[0045] Furthermore, a control method for an air conditioning system 1 according to the first embodiment includes a heat source 60 that heats or cools chilled or hot water, a plurality of air conditioners 40 through which chilled or hot water flows, a plurality of control valves 50 that are connected to each of the air conditioners 40 and control the flow rate of the chilled or hot water flowing through each of the air conditioners 40, a chilled or hot water pump 20 that supplies chilled or hot water to each of the air conditioners 40, piping 30, inlet piping 31, and outlet piping 32 that sequentially connect the heat source 60, the chilled or hot water pump 20, each of the air conditioners 40, and each of the control valves 50, and the control method for controlling an air conditioning system 1 according to the first embodiment includes a control method for controlling an air conditioning system 1 according to the first embodiment, The air conditioning system 1 has the steps of detecting whether the state of the elements related to the operation of the air conditioner conforms to the state of the preset elements, and if the state of the elements related to the operation of the air conditioner does not conform to the state of the preset elements, the setting unit 90 sets the chilled / hot water pump output to a first output, and if the state of the elements related to the operation of the air conditioner 40 conforms to the state of the preset elements, the setting unit 90 sets the chilled / hot water pump output to a second output, and controls the chilled / hot water pump 20 with the chilled / hot water pump output, thereby making it possible to provide an air conditioning system 1 that consumes a reduced amount of energy.

[0046] The detection unit also includes a flow rate detection unit of the control valve 50 that measures the air conditioner flow rate for each of the multiple air conditioners 40, and the state of the preset element is such that the air conditioner flow rates for each of the multiple air conditioners 40 are all below a predetermined value, so that the air conditioner load of each air conditioner 40 can be detected.

[0047] Embodiment 2 Next, an air conditioning system 1 according to a second embodiment of the present invention will be described. In the following embodiments, components denoted by the same reference numerals as those in Figures 1 to 12 of the first embodiment are the same or similar components, and detailed description thereof will be omitted. In contrast to the first embodiment, the second embodiment reduces the differential pressure ratio of the maximum air conditioner differential pressure based on the amount of power consumed by lighting and electrical equipment in the room in which each air conditioner 40 is installed.

[0048] During cooling operation of each air conditioner 40, the lights and electrical appliances connected to the outlets in the room where each air conditioner 40 is installed generate heat in proportion to their power consumption, and the loads from the lights and electrical appliances become part of the air conditioner load. The maximum design values ​​for the lighting and electrical appliance loads in the air conditioning system 1 are set based on the case where the power consumption of the lights and electrical appliances is at its maximum. However, the actual power consumption of the lights and electrical appliances during cooling operation of the air conditioning system 1 is less than the design maximum power consumption. Therefore, the lighting and electrical appliance loads during actual cooling operation of the air conditioning system 1 are less than the design lighting and electrical appliance loads. Therefore, by considering the power consumption of the lights, outlets, and other indoor appliances in the building without measuring the air conditioner flow rate of the air conditioner 40 in advance, it is possible to confirm that the air conditioner load is below a predetermined percentage of the design maximum air conditioner load.

[0049] Specifically, the control unit 70 has recorded in advance, as threshold values, the lighting and electrical appliance loads and the power consumption corresponding to the lighting and electrical appliance loads when the air conditioning load of each air conditioner 40 is 90% or less or 95% or less of the design maximum. Next, during cooling operation of the air conditioning system 1, the power detection unit 83 detects the current power consumption by the lighting and electrical appliances in the room where each air conditioner 40 is installed. Next, the control unit 70 determines whether the current power consumption by the lighting and electrical appliances in the room where each air conditioner 40 is installed, detected by the power detection unit 83, is equal to or less than the power consumption threshold when the air conditioning load of the air conditioner 40 is 90% or less or 95% or less of the design maximum.

[0050] If the current power consumption by the lighting and electrical equipment in the room in which each air conditioner 40 is installed is equal to or less than the power consumption threshold when the air conditioning load of each air conditioner 40 is equal to or less than 90% of the design maximum, the differential pressure ratio of the maximum air conditioning differential pressure can be set to 20%, as shown in Fig. 10. Also, if the current power consumption by the lighting and electrical equipment in the room in which each air conditioner 40 is installed is equal to or less than the power consumption threshold when the air conditioning load of each air conditioner 40 is equal to or less than 95% of the design maximum, the differential pressure ratio of the maximum air conditioning differential pressure can be set to 40%, as shown in Fig. 10.

[0051] Next, if the control unit 70 determines that the current power consumption by the lighting and electrical equipment in the room where the air conditioner 40 is installed is equal to or less than the power consumption threshold when the air conditioning load of the air conditioner 40 is 90% or less or 95% or less of the design maximum, the air conditioner control unit 45 sets the maximum air conditioning load of each air conditioner 40 to be within the range of 90% or less or 95% or less of the design maximum. Next, the setting unit 90 sets the output of the chilled / hot water pump 20 so that the differential pressure required for the total value of the air conditioning flow rate required by the system including at least each air conditioner 40, the piping 30, the inlet piping 31, and the outlet piping 32 is achieved, and so that the differential pressure ratio of the maximum air conditioning differential pressure is 20% or 40%. Next, the control unit 70 controls the chilled / hot water pump 20 based on the second output of the chilled / hot water pump 20 newly set by the setting unit 90.

[0052] As described above, when setting the output of the chilled / hot water pump 20 using the setting unit 90, by considering the power consumption of lighting, outlets, etc. in the room where the air conditioner 40 is installed, in order to avoid the risk of insufficient capacity of the air conditioner 40, it is necessary to consider, for example, setting the differential pressure ratio of the maximum air conditioner differential pressure with some leeway rather than reducing the differential pressure ratio of the maximum air conditioner differential pressure to 20%, and gradually reducing the differential pressure ratio of the maximum air conditioner differential pressure after confirming that there is no impairment to the capacity of the air conditioner 40. Furthermore, when the air conditioners 40 include air conditioners 40 that do not include loads from lighting and outlets, such as air conditioners for electrical rooms, or outdoor air conditioners, it is also necessary to check the air conditioning capacity based on the temperature of the air sent from the air conditioner 40.

[0053] As described above, in the air conditioning system 1 according to the second embodiment, the condition detection unit includes a power detection unit 83 that detects the power consumption of electrical equipment in a room in which multiple air conditioners 40 are installed, and the state of the preset element is that the power consumption of electrical equipment in a room in which multiple air conditioners 40 are installed is below a predetermined value, so that the air conditioning load of each air conditioner 40 can be detected in a simple manner without measuring the air conditioning flow rate of each air conditioner 40.

[0054] In the second embodiment, the power detection unit 83 detects based on the amount of power consumption that the maximum device load of the air conditioner 40 is 90% or less or 95% or less of the design capacity, but the value of the maximum device load of the air conditioner 40 is an example and is not limited to this. As shown in Fig. 9, the power detection unit 83 may detect based on the amount of power consumption that the maximum device load of the air conditioner 40 is any value greater than 0% and less than or equal to 100% of the design capacity. Also, for example, as shown in Fig. 10, if the maximum device load of the air conditioner 40 is 98% of the design capacity, the setting unit 90 can set the output of the chilled or hot water pump 20 so that the differential pressure ratio of the maximum air conditioner differential pressure is 70%.

[0055] Embodiment 3 Next, an air conditioning system according to a third embodiment of the present invention will be described. In contrast to the first embodiment, the third embodiment reduces the differential pressure ratio of the maximum air conditioning differential pressure by detecting the specific enthalpy of the outside air of the facility or building in which the air conditioning system is installed. When outside air is introduced into all of the air conditioners 40 in the air conditioning system 1 shown in FIG. 1, the maximum air conditioner load of the air conditioners 40 is expressed by the following equation (1). q AC =q R +q O +q F +q D ···(1) where: q AC : Heat processing amount required for the air conditioner 40 (maximum air conditioner load) (W) q R :Indoor load (W) q O :Outside air load (W) q F : Heat load from the fan (W) q D : Heat load through duct (W) is.

[0056] In the widely adopted variable air volume air conditioning system, indoor conditions differ for each variable air volume zone, so the return air condition and the supply air condition are generally measured at the inlet and outlet of the air conditioner. At this measurement point, the return air is added with the heat passing through the duct and the temperature rise due to the power effectively used by the fan, and if the heat generated by the motor is inside the air conditioner and acts as a load, the supply air temperature rise is added to the air conditioner outlet temperature. When the indoor load is calculated based on the air conditioner inlet and outlet state, it is a load that includes the load generated between the air conditioner inlet and outlet (hereinafter referred to as internal load), and is expressed in the following formula (2) as q RAC The maximum air conditioner load of the air conditioner 40 is expressed by the following formula (3). q RAC =q R +q F +q D ···(2) q AC =q RAC +q O ···(3) where: q RAC : Internal load due to air conditioner entrance / exit status (W) is.

[0057] Furthermore, the above equations (2) and (3) can be expressed by the following equations (4), (5), and (6). q RAC =1.2QΔh RAC ···(4) q O =1.2Q O Δh o ···(5) q AC =1.2(QΔh RAC +Q O Δh o ) ···(6) where: Δh RAC : Enthalpy difference between the air conditioner inlet and outlet (J / g) Q: Air conditioner air flow rate (l / s) Q O : Volume of outside air taken in (l / s) Δh O : Indoor / outdoor enthalpy difference (J / g) is.

[0058] To calculate the maximum air conditioner load using equation (6), the reduction from the maximum capacity of the air conditioner can be calculated if the control unit 70 knows the air conditioner inlet / outlet enthalpy difference, air volume, outdoor air volume, and outdoor air enthalpy difference. When outdoor air is being introduced to all air conditioners 40 in the air conditioning system 1, the differential pressure can be easily reduced by determining only the outdoor air conditions common to all air conditioners 40. To confirm that the air conditioner load is below the target based only on the outdoor air load, it is sufficient to confirm that the outdoor air condition is in a state where the differential pressure ratio of the maximum air conditioner differential pressure to be reduced is divided by the outdoor air load rate.

[0059] For example, if the goal is to reduce the differential pressure ratio of the maximum air conditioner differential pressure by 5%, it is sufficient to check whether the outdoor air condition is in a state where the differential pressure ratio value of 5% to be reduced is divided by the outdoor air load rate. If the outdoor air load rate is 30%, it is sufficient to check whether the differential pressure ratio value is -16.7%, which is -5% divided by the outdoor air load rate of 30%. In this case, for example, when the outdoor air temperature is 34.8°C and 58%, the specific enthalpy is 87.5 J / g, and when the indoor air temperature is 26.0°C and 50%, the specific enthalpy is 52.9 J / g, so the specific enthalpy difference between the outdoor air and indoor air is 87.5-52.9=34.6J / g (7) and the outdoor air specific enthalpy resulting in the above-mentioned -16.7% outdoor air load is 81.93 J / g. At this outdoor air specific enthalpy resulting in this -16.7% outdoor air load, the temperature is 34.1°C when the relative humidity is 55%. In other words, if the outdoor air state has an outdoor air specific enthalpy of 81.93 J / g or less, which results in the above-mentioned -16.7% outdoor air load, the differential pressure ratio of the maximum air conditioning differential pressure of the air conditioner 40 can be reduced by 5%, and therefore the air conditioning load can be reduced by 5%. Note that in the third embodiment, the various numerical conditions described above are merely examples, and other numerical conditions may be used to calculate the maximum air conditioning load.

[0060] Since the outdoor air specific enthalpy is determined by the outdoor air temperature and outdoor air humidity, when the control unit 70 operates the chilled / hot water pump 20 based on the first output set by the setting unit 90 in the air conditioning system 1 shown in FIG. 1 , the outdoor air specific enthalpy detection unit 81 detects the outdoor air temperature and outdoor air humidity and detects the outdoor air specific enthalpy from the outdoor air temperature and outdoor air humidity. Next, the control unit 70 obtains the air conditioning load of the air conditioner 40 during operation of the air conditioning system 1 based on the outdoor air specific enthalpy and can calculate the air conditioning load reduction rate from the maximum air conditioning load. Next, the setting unit 90 sets the output of the chilled / hot water pump 20 to generate a differential pressure corresponding to this air conditioning load reduction rate. Next, the control unit 70 controls the chilled / hot water pump 20 based on the second output of the chilled / hot water pump 20 set by the setting unit 90. This reduces the maximum air conditioning differential pressure and reduces the output of the chilled / hot water pump 20, compared to when the air conditioning system 1 is operated at maximum air conditioning load and the chilled / hot water pump 20 is set to the first output, thereby reducing the amount of energy consumed by the air conditioning system 1.

[0061] As described above, in the air conditioning system 1 according to the third embodiment, all of the multiple air conditioners 40 are air conditioners 40 that introduce outside air, the detection unit includes an outside air specific enthalpy detection unit 81, and the state of the preset element is that the outside air specific enthalpy of the outside air is below a predetermined value, so that the amount of energy consumed by the air conditioning system 1 can be reduced in a simple manner without measuring the air conditioning flow rate of each air conditioner 40.

[0062] Next, a modified example of the air conditioning system 1 according to the third embodiment will be described. In Japan, the outdoor air specific enthalpy in the same building is particularly large in the summer, and conversely, the outdoor air specific enthalpy is small in seasons other than summer. Therefore, the outdoor air specific enthalpy when determining that it is summer is recorded as a threshold value in the control unit 70, and this threshold value is compared with the outdoor air specific enthalpy detected by the outdoor air specific enthalpy detection unit 81. If the outdoor air specific enthalpy is smaller than the threshold value, the setting unit 90 may automatically reset the output setting value of the chilled / hot water pump 20 to a value lower than the summer setting value, or the administrator of the air conditioning system 1 may manually reset the output setting value of the chilled / hot water pump 20 set in the setting unit 90 to a setting value other than the summer setting value. In addition, if the outside air specific enthalpy is equal to or greater than a threshold value, the setting unit 90 may automatically reset the output setting value of the chilled / hot water pump 20 to the summer setting value, or the administrator of the air conditioning system 1 may manually reset the output setting value of the chilled / hot water pump 20 set in the setting unit 90 to the summer setting value.

[0063] In the modification of the third embodiment, the setting of the output setting of the chilled / hot water pump 20 based on the outdoor air specific enthalpy when determining that it is summer is used as a threshold value as an element for resetting the output setting of the chilled / hot water pump 20. The output setting of the chilled / hot water pump may be reset based on other conditions. For example, the outdoor air specific enthalpy in winter may be used as the threshold value, or two or more types of outdoor air specific enthalpy throughout the year may be used as threshold values.

[0064] Embodiment 4 Next, an air conditioning system 1 according to a fourth embodiment of the present invention will be described. In contrast to the third embodiment, the fourth embodiment reduces the differential pressure ratio of the maximum air conditioner differential pressure based on the air conditioner inlet / outlet enthalpy difference. In the air conditioning system 1 shown in Fig. 1, when the control unit 70 operates the chilled / hot water pump 20 based on the first output set by the setting unit 90, the inlet sensor 46 of the air inlet 41 detects the air temperature, humidity, and air volume of the air being taken in, and the outlet sensor 47 of the outlet 44 detects the air temperature, humidity, and air volume of the air being blown out. As a result, the air conditioning load detection unit 82 calculates Δh RAC(Air conditioner inlet / outlet enthalpy difference), Q (Air conditioner airflow), Q O (amount of outside air taken in), Δh O Since the difference between indoor and outdoor enthalpies is obtained, the control unit 70 can obtain qRAC (internal load due to the air conditioner entrance / exit state) using the above formula (6).

[0065] This allows the control unit 70 to obtain the air conditioner load of the air conditioner 40 when the air conditioning system 1 is operating, and to calculate the air conditioner load reduction rate from the designed maximum air conditioner load. Then, based on this air conditioner load reduction rate, the setting unit 90 sets the second output of the chilled / hot water pump 20. Next, based on the second output of the chilled / hot water pump 20 set by the setting unit 90, the chilled / hot water pump 20 is controlled.

[0066] Thus, in the air conditioning system 1 according to the fourth embodiment, the detection unit includes an inlet sensor 46, an outlet sensor 47, and an air conditioning load detection unit 82 that detect air temperature, humidity, and air volume, which are provided at the air inlets 41 and outlets 44 of the multiple air conditioners 40, and the state of the preset elements is that the product of the air temperature, humidity, and air volume at the air inlets 41 and outlets 44 of the multiple air conditioners 40 is below a predetermined value, so that the amount of energy consumed by the air conditioning system 1 can be reduced in a simple manner without measuring the air conditioning flow rate of each air conditioner 40.

[0067] Next, a modification of the fourth embodiment will be described. RACRegarding the air conditioner inlet / outlet enthalpy difference, for example, the state of the air blown during operation at maximum load of the air conditioner 40 is a relative humidity of about 90% during cooling. Therefore, assuming a relative humidity of 90%, the air conditioner inlet / outlet enthalpy difference can be obtained based only on the blown air temperature. Specifically, the air conditioning load detection unit 82 determines whether the product of the blown air temperature and air volume at the air outlet 44 measured by the air outlet sensor 47 of each air conditioner 40 is equal to or less than a predetermined threshold, thereby determining whether the rate of reduction in the air conditioner load from the maximum air conditioner load designed for each air conditioner 40 is equal to or less than a predetermined value. Note that, although the relative humidity during cooling is assumed to be 90% here, this value is merely an example, and other values ​​may be set according to the actual state of the air blown by the air conditioner 40.

[0068] Furthermore, as a modification of the first to fourth embodiments of the present invention, the differential pressure ratio of the maximum air conditioner differential pressure may be reduced by extending the pre-cooling operation time of each air conditioner 40 in the air conditioning system 1. In a facility or building in which the air conditioning system 1 is installed, if the load on the air conditioner 40 is greatest during pre-cooling operation, it is considered possible to reduce the air conditioner load and the differential pressure ratio of the maximum air conditioner differential pressure by extending the pre-cooling time. In one example, by extending the pre-cooling time of the air conditioner 40 from 30 minutes to 40 minutes, the maximum load on the air conditioner 40 can be reduced to 95 W / m 2 to 80W / m 2 and the maximum differential pressure ratio for the air conditioner is reduced by 16%.

[0069] In this way, by extending the pre-cooling time of the air conditioning system 1, the differential pressure ratio of the maximum air conditioner differential pressure of the air conditioning system 1 can be reduced in a simple manner, thereby reducing the amount of energy consumed by the air conditioning system 1.

[0070] The air conditioning system 1 and its control method according to embodiments 1 to 4 of the present invention can be used in existing facilities and buildings without the need to introduce new equipment, thereby reducing the costs associated with the air conditioning system 1 and its control method.

[0071] The configurations of the air conditioning systems 1, 1b described in the first to fourth embodiments of the present invention are merely examples, and other configurations may be used. For example, the number of air conditioners 40 and control valves 50 included in the air conditioning systems 1, 1b may be ten or more, a plurality of chilled / hot water pumps 20 may be provided, or bypass piping may be provided in the piping 30 between the heat source 60 and the chilled / hot water pump 20. Furthermore, the control methods of the air conditioning systems 1, 1b described in the first to fourth embodiments of the present invention are merely examples, and the control methods may be changed as appropriate, or the control methods of the air conditioning systems 1, 1b described in the first to fourth embodiments of the present invention may be used in appropriate combination.

[0072] Furthermore, in the first, third and fourth embodiments of the present invention, the air conditioning systems 1 and 1b perform cooling operation, but may also perform heating operation.

[0073] Furthermore, in the first to fourth embodiments of the present invention, the air conditioning system 1 has the hot and cold water pump 20, but may also have a heat source pump for use as a heat source in addition to this. [Explanation of symbols]

[0074] 20 chilled / hot water pump, 30 piping, 31 inlet side piping, 32 outlet side piping, 40 air conditioner, 41 air intake (inlet / outlet), 42 outlet (inlet / outlet), 46 intake sensor (air conditioning load detection unit), 47 outlet sensor (air conditioning load detection unit), 50 control valve (air conditioning flow rate detection unit), 60 heat source, 70 control unit, 80 detector (detection unit), 81 outdoor air specific enthalpy detection unit (detection unit), 82 air conditioning load detection unit (detection unit), 83 power detection unit (detection unit), 90 setting unit.

Claims

1. A heat source for heating or cooling cold or hot water; a plurality of air conditioners through which the hot and cold water circulates; a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; a detection unit that detects whether the state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit that sets the chilled / hot water pump output of the chilled / hot water pump so that the differential pressure between the upstream side and downstream side of the chilled / hot water pump becomes the differential pressure necessary for the circulation of the total air conditioner flow rate required by a system that includes at least each of the air conditioners and the piping; a control unit that controls the chilled / hot water pump at the chilled / hot water pump output set by the setting unit; Equipped with When the detection unit detects that the state of an element of the air conditioner does not match a preset element state, the setting unit sets the chilled or hot water pump output to a first output; When the detection unit detects that the state of the element of the air conditioner matches the state of the element that has been preset, the setting unit sets the output of the chilled or hot water pump to a second output; the detection unit includes an air conditioner flow rate detection unit that measures an air conditioner flow rate for each of the plurality of air conditioners, An air conditioning system in which the preset element state is such that the air conditioner flow rates for each of the plurality of air conditioners are all equal to or less than a predetermined value.

2. A heat source for heating or cooling cold or hot water; a plurality of air conditioners through which the hot and cold water circulates; a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; a detection unit that detects whether the state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit that sets the chilled / hot water pump output of the chilled / hot water pump so that the differential pressure between the upstream side and downstream side of the chilled / hot water pump becomes the differential pressure necessary for the circulation of the total air conditioner flow rate required by a system that includes at least each of the air conditioners and the piping; a control unit that controls the chilled / hot water pump at the chilled / hot water pump output set by the setting unit; Equipped with When the detection unit detects that the state of an element of the air conditioner does not match a preset element state, the setting unit sets the chilled or hot water pump output to a first output; When the detection unit detects that the state of the element of the air conditioner matches the state of the element that has been preset, the setting unit sets the output of the chilled or hot water pump to a second output; the detection unit includes a power detection unit that detects the amount of power used by electrical devices in the room where the plurality of air conditioners are installed, An air conditioning system in which the state of the preset element is that the power consumption of electrical equipment in a room where the plurality of air conditioners are installed is equal to or less than a predetermined value.

3. A heat source for heating or cooling cold or hot water; a plurality of air conditioners through which the hot and cold water circulates; a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; a detection unit that detects whether the state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit that sets the chilled / hot water pump output of the chilled / hot water pump so that the differential pressure between the upstream side and downstream side of the chilled / hot water pump becomes the differential pressure necessary for the circulation of the total air conditioner flow rate required by a system that includes at least each of the air conditioners and the piping; a control unit that controls the chilled / hot water pump at the chilled / hot water pump output set by the setting unit; Equipped with When the detection unit detects that the state of an element of the air conditioner does not match a preset element state, the setting unit sets the chilled or hot water pump output to a first output; When the detection unit detects that the state of the element of the air conditioner matches the state of the element that has been preset, the setting unit sets the output of the chilled or hot water pump to a second output; The plurality of air conditioners are all air conditioners that introduce outside air, the detection unit includes an outside air specific enthalpy detection unit, An air conditioning system in which the preset element state is that the specific enthalpy of the outside air is equal to or lower than a predetermined value.

4. A heat source for heating or cooling cold or hot water; a plurality of air conditioners through which the hot and cold water circulates; a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; a detection unit that detects whether the state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit that sets the chilled / hot water pump output of the chilled / hot water pump so that the differential pressure between the upstream side and downstream side of the chilled / hot water pump becomes the differential pressure necessary for the circulation of the total air conditioner flow rate required by a system that includes at least each of the air conditioners and the piping; a control unit that controls the chilled / hot water pump at the chilled / hot water pump output set by the setting unit; Equipped with When the detection unit detects that the state of an element of the air conditioner does not match a preset element state, the setting unit sets the chilled or hot water pump output to a first output; When the detection unit detects that the state of the element of the air conditioner matches the state of the element that has been preset, the setting unit sets the output of the chilled or hot water pump to a second output; the detection unit includes an air conditioning load detection unit that is provided at an entrance or exit of the plurality of air conditioners and detects air temperature, humidity, and air volume; An air conditioning system in which the state of the preset element is such that the product of the air temperature, humidity and air volume at the entrances and exits of the plurality of air conditioners is equal to or less than a predetermined value.

5. A heat source for heating or cooling cold or hot water; Multiple air conditioners with hot and cold water circulating inside, a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; A control method for an air conditioning system comprising: detecting, by a detection unit, whether a state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit setting the chilled / hot water pump output of the chilled / hot water pump to a first output when the state of an element related to the operation of the air conditioner does not match the state of the preset element; When a state of an element related to the operation of the air conditioner matches the state of the preset element, the setting unit sets the chilled / hot water pump output to a second output; controlling the chilled / hot water pump using the chilled / hot water pump output; the detection unit includes an air conditioner flow rate detection unit that measures an air conditioner flow rate for each of the plurality of air conditioners, A method for controlling an air conditioning system, wherein the preset element state is such that the air conditioner flow rates for each of the plurality of air conditioners are all equal to or less than a predetermined value.

6. A heat source for heating or cooling cold or hot water; Multiple air conditioners with hot and cold water circulating inside, a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; A control method for an air conditioning system comprising: detecting, by a detection unit, whether a state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit setting the chilled / hot water pump output of the chilled / hot water pump to a first output when the state of an element related to the operation of the air conditioner does not match the state of the preset element; When a state of an element related to the operation of the air conditioner matches the state of the preset element, the setting unit sets the chilled / hot water pump output to a second output; controlling the chilled / hot water pump using the chilled / hot water pump output; the detection unit includes a power detection unit that detects the amount of power used by electrical devices in the room where the plurality of air conditioners are installed, The method for controlling an air conditioning system, wherein the preset element state is that the power consumption of electrical equipment in a room where the plurality of air conditioners are installed is equal to or less than a predetermined value.

7. A heat source for heating or cooling cold or hot water; Multiple air conditioners with hot and cold water circulating inside, a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; A control method for an air conditioning system comprising: detecting, by a detection unit, whether a state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit setting the chilled / hot water pump output of the chilled / hot water pump to a first output when the state of an element related to the operation of the air conditioner does not match the state of the preset element; When a state of an element related to the operation of the air conditioner matches the state of the preset element, the setting unit sets the chilled / hot water pump output to a second output; controlling the chilled / hot water pump using the chilled / hot water pump output; The plurality of air conditioners are all air conditioners that introduce outside air, the detection unit includes an outside air specific enthalpy detection unit, The method for controlling an air conditioning system, wherein the predetermined element state is that the specific enthalpy of the outside air is equal to or lower than a predetermined value.

8. A heat source for heating or cooling cold or hot water; Multiple air conditioners with hot and cold water circulating inside, a plurality of control valves connected to the air conditioners, respectively, for controlling the flow rate of the hot and cold water flowing through the air conditioners; a cold / hot water pump for supplying the cold / hot water to each of the air conditioners; piping that connects the heat source, the hot and cold water pump, the air conditioners, and the control valves; A control method for an air conditioning system comprising: detecting, by a detection unit, whether a state of an element related to the operation of the air conditioner conforms to a preset element state; a setting unit setting the chilled / hot water pump output of the chilled / hot water pump to a first output when the state of an element related to the operation of the air conditioner does not match the state of the preset element; When a state of an element related to the operation of the air conditioner matches the state of the preset element, the setting unit sets the chilled / hot water pump output to a second output; controlling the chilled / hot water pump using the chilled / hot water pump output; the detection unit includes an air conditioning load detection unit that is provided at an entrance or exit of the plurality of air conditioners and detects air temperature, humidity, and air volume; A method for controlling an air conditioning system, wherein the state of the preset element is a state in which the product of the air temperature, humidity and air volume at the entrances and exits of the plurality of air conditioners is equal to or less than a predetermined value.

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