Air conditioning system

Abstract

To provide an air conditioning system capable of facilitating securing of an energy saving effect and prevention deterioration of thermal environment by setting a looser rated value of a water feed temperature.SOLUTION: An air conditioning system includes: a refrigerator that supplies cold / hot water having a predetermined temperature; an air conditioner that air-conditions a target space by receiving supply of the cold / hot water; measurement sections 21, 41 that measure a first parameter related to air conditioning capacity performed by the air conditioner; a calculation section 61 that calculates allowance of the air conditioning capacity on the basis of a second parameter related to a maximum air conditioning capacity of the air conditioner when the supplied cold / hot water is used and the first parameter; a control section 62 that performs control for changing the predetermined temperature relative to the refrigerator to change the air conditioning capacity of the air conditioner when the allowance exceeds a predetermined threshold range; and a change section 63 that changes a lower limit of the predetermined threshold range when a preset predetermined condition that is a predetermined condition where a load of the air conditioner changes is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Buildings and other structures that use central heat source air conditioning systems are known. In these air conditioning systems, cooling is performed using chilled water produced by a heat source machine, and heating is performed using hot water.

[0003] In the case of air conditioning, the heat source machine produces chilled water at around 7°C, which is then pumped to each room in the building. The air conditioners installed in each room exchange heat between the chilled water and the air. The air cooled by the heat exchange is then blown out into the room. Air conditioners include air handling units (hereafter also referred to as AHUs) and fan coil units (hereafter also referred to as FCUs).

[0004] It is known that setting the temperature of chilled water produced by a heat source machine to a temperature higher than a predetermined rated temperature improves the energy efficiency of the heat source machine compared to producing chilled water at the rated temperature. In other words, it is known that the amount of energy consumed by the heat source machine to produce chilled water is reduced, resulting in greater energy savings.

[0005] On the other hand, it is known that if the temperature of the supplied chilled water is higher than the rated temperature, the cooling capacity of the air conditioner to which the chilled water is supplied will decrease. For example, during periods of high cooling load, such as midsummer, the cooling capacity of the air conditioner may be insufficient. Along with the cooling capacity, the dehumidifying capacity of the air conditioner may also decrease, resulting in a lack of dehumidifying capacity.

[0006] Similarly, in the case of heating, it is known that if the temperature of the hot water produced by the heat source machine is set to a temperature lower than a predetermined rated temperature, the amount of energy consumed by the heat source machine to produce hot water is reduced compared to when hot water is produced at the rated temperature, resulting in greater energy savings. Also, there is a possibility that the heating capacity of the air conditioner will be insufficient during periods of high heating load.

[0007] Because there is a possibility that the cooling, heating, and dehumidifying capacities of air conditioners may be insufficient, chilled water and hot water (hereinafter referred to as chilled and hot water when there is no need to distinguish between chilled water and hot water) at the same rated temperature are supplied to air conditioners throughout the year, and the temperature of the chilled and hot water is often not changed.

[0008] As an exception, large buildings with facility managers may change the temperature of the hot and cold water. The facility managers use building automation systems (hereinafter referred to as BAS) to monitor the air conditioning status and change the temperature of the hot and cold water.

[0009] The temperature of chilled and hot water is changed during intermediate periods when the cooling and heating loads are smaller than in other periods and there is little possibility of the air conditioner's cooling or heating capacity being insufficient. During intermediate periods, the facility manager changes the temperature of chilled and hot water based on their own experience. Intermediate periods are seasons of the year other than summer and winter, such as spring and autumn.

[0010] In the following, setting the chilled water temperature higher than the rated value in the case of cooling, and setting the hot water temperature lower than the rated value in the case of heating, will be referred to as "relaxed water supply temperature." This relaxation of water supply temperature is known as an energy-saving measure in central heat source air conditioning systems (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] "Building Energy Conservation Guidebook 2019: Energy Conservation Promotion Methods and Energy Conservation Technologies," Energy Conservation Center, Japan, Diagnostic Guidance Department / Diagnostic Technology Department, p.14 Summary of the Invention [Problem to be solved by the invention]

[0012] If the water supply temperature was reduced as described above, the thermal environment in the room could deteriorate if the air conditioning unit's heating / cooling capacity was insufficient. If the thermal environment deteriorated, the comfort of the room occupants could decrease, and there was a possibility that the occupants would complain.

[0013] In the case of a building that is intended to be rented to others for use as an office or store, a deterioration in the thermal environment may be a breach of the lease agreement on the part of the building owner, and may also lead to tenants moving out of the building.

[0014] Conventional tenant buildings did not have a means to quantitatively grasp the insufficient heating and cooling capacity of air conditioners or the possibility of such insufficiency. In such a situation, when setting the temperature range and implementation period for water supply temperature relaxation, the temperature range and implementation period were set based on the analysis results conducted by specialized companies such as equipment sub-constructors. In this case, since it was difficult to change the settings in response to changes in the situation, the settings were set with a sufficient margin to avoid the risk of insufficient heating and cooling capacity.

[0015] By taking such careful measures to avoid risks, the settings are set on the safe side with a margin secured. For example, the time for which the water temperature can be relaxed may be shorter than the time it can actually be relaxed, and the temperature range for which the water temperature can be relaxed may be smaller than the temperature range it can actually be relaxed.

[0016] In other words, there is a problem in that the reduction in the amount of energy consumed by the air conditioning system due to the water supply temperature reduction is small. In other words, there is a problem in that the energy saving effect obtained by the water supply temperature reduction is small.

[0017] The present invention has been made to solve the above-mentioned problems, and aims to provide an air conditioning system that can easily achieve both energy-saving effects by mitigating the water supply temperature and prevention of deterioration of the thermal environment. [Means for solving the problem]

[0018] In order to achieve the above object, the present invention provides the following means. The air conditioning system of the present invention includes a chiller that supplies chilled or hot water at a predetermined temperature, an air conditioner that receives the supply of chilled or hot water and air-conditions a target space, a measurement unit that measures a first parameter related to the air conditioning capacity of the air conditioner, a calculation unit that calculates the margin of air conditioning capacity based on the first parameter and a second parameter related to the maximum air conditioning capacity of the air conditioner when the supplied chilled or hot water is used, a control unit that controls the chiller to change the predetermined temperature when the margin exceeds a predetermined threshold range, and changes the air conditioning capacity of the air conditioner, and a change unit that changes the lower limit of the predetermined threshold range when a predetermined condition under which the load of the air conditioner changes is satisfied.

[0019] According to the air conditioning system of the present invention, if the calculated margin exceeds a predetermined threshold range, the predetermined temperature of the chilled or hot water is changed to moderate the supply water temperature. For example, if the margin is greater than the predetermined threshold range, the chilled water temperature is changed to a value that reduces the air conditioning capacity of the air conditioner. This makes it easier to reduce the amount of energy consumed when supplying chilled or hot water, and makes it easier to ensure energy savings by moderately adjusting the supply water temperature.

[0020] Furthermore, if the margin is smaller than a predetermined threshold range, the chilled water temperature is changed to increase the air conditioning capacity of the air conditioner. This makes it easier to ensure the air conditioning capacity of the air conditioner and to prevent deterioration of the thermal environment due to relaxation of the water supply temperature.

[0021] The margin related to the air conditioning capacity of the air conditioner is calculated based on the first parameter measured by the measurement unit. Therefore, compared to analysis performed by a specialist company, it is easier to identify insufficient air conditioning capacity of the air conditioner at an early stage and to avoid insufficient air conditioning capacity at an early stage.

[0022] Furthermore, by controlling using the margin based on the first parameter, it becomes easier to reduce the safety margin in the temperature mitigation range and implementation period compared to control using analysis performed by a specialist company. As a result, it becomes easier to ensure energy-saving effects by mitigating the water supply temperature.

[0023] It is possible to disclose to tenants the margins before and after control, etc. By disclosing such margins, it becomes possible to quantitatively explain the energy-saving effects and thermal environment of the target space.

[0024] When the load on the air conditioner changes, changing the lower limit of the predetermined threshold range makes it easier to further reduce the amount of energy consumed when supplying hot or cold water, and makes it easier to ensure energy savings by relaxing the water supply temperature. Changes in the load on the air conditioner include, for example, changes in the weather or changes in the way the room, which is the target space, is used.

[0025] In the above invention, it is preferable that a load measurement unit is further provided that measures an air conditioning load parameter related to the load of the air conditioner, and that the change unit changes the lower limit of the threshold range when the amount of change in the air conditioning load parameter during a change period becomes equal to or greater than a judgment value.

[0026] By changing the lower limit of the threshold range based on the air conditioning load parameter, it becomes easier to increase the energy saving effect of the air conditioner and to reduce the risk of insufficient air conditioning capacity of the air conditioner. For example, the smaller the lower limit of the threshold range, the higher the energy saving effect, and the larger the lower limit of the threshold range, the lower the risk of insufficient air conditioning capacity.

[0027] By changing the lower limit of the value range based on the result of comparing the amount of change in the air conditioning load parameter during the change period with the judgment value, for example, when the predetermined temperature of chilled or hot water is changed, the lower limit of the threshold range can be changed based on the changed predetermined temperature. The predetermined period can be, for example, the period from when the predetermined temperature of chilled or hot water is changed until the chilled or hot water at the changed temperature reaches the air conditioner. Specifically, the period can be several minutes to several tens of minutes.

[0028] In the above invention, it is preferable that a prediction unit is further provided that predicts a predicted parameter, which is the air conditioning load parameter, after a predetermined time lag, and that the change unit changes the lower limit of the threshold range based on an increase or decrease in the predicted parameter based on the air conditioning load parameter.

[0029] By changing the lower limit of the threshold range based on an increase or decrease in the prediction parameter, it becomes easier to further increase the energy-saving effect of the air conditioner and to further reduce the risk of insufficient air-conditioning capacity in the air conditioner, compared to when the prediction parameter is not used. For example, if the load on the air conditioner is expected to decrease after a time lag, the lower limit of the threshold range is changed to increase the energy-saving effect of the air conditioner. Also, if the load on the air conditioner is expected to increase after a time lag, the lower limit of the threshold range is changed to reduce the risk of insufficient air-conditioning capacity in the air conditioner.

[0030] In the above invention, it is preferable that the calculation unit calculates the margin for each of the plurality of air conditioners, and the control unit performs control based on the margin that has the smallest value among the plurality of margins.

[0031] This reduces the likelihood of a margin value smaller than the predetermined threshold range, which means that air conditioners with insufficient air conditioning capacity are less likely to occur, making it easier to prevent deterioration of the thermal environment due to relaxation of the water supply temperature.

[0032] In the above invention, it is preferable that the control unit does not perform control to change the specified temperature even if some of the multiple margins related to the multiple air conditioners that perform air conditioning on the same target space exceed the specified threshold range, if the remaining margins do not exceed the specified threshold range.

[0033] By doing this, even if an air conditioner has a margin smaller than the predetermined threshold range and does not have sufficient air conditioning capacity, there will still be air conditioners with sufficient air conditioning capacity among the multiple air conditioners that condition the same target space. As a result, the air conditioners with sufficient capacity can compensate for the air conditioners that do not have sufficient capacity, making it easier to prevent the thermal environment from deteriorating.

[0034] In the above invention, it is preferable that the calculation unit calculates a group margin, which is an average value using a predetermined coefficient, based on the multiple margins associated with the multiple air conditioners that condition the target space and that satisfy predetermined conditions regarding temperature difference, and that the control unit controls the refrigerators to change the predetermined temperature when the group margin exceeds the predetermined threshold range instead of the margins.

[0035] By using the group margin in this way, it is possible to control multiple air conditioners in a target space that meet certain conditions as a single unit. Here, the predetermined condition regarding the temperature difference can be, for example, that the temperature difference between temperatures measured at multiple locations in the target space is equal to or less than a predetermined value. Furthermore, the predetermined coefficient can be, for example, the value of the air conditioning capacity of the air conditioners.

[0036] An example of the predetermined value of the temperature difference is the sum of the value of the mutual measurement error between the multiple temperature sensors used to control the air conditioner and the value of the temperature difference that causes a difference in human thermal sensation.

[0037] In the above invention, it is preferable that a change unit is further provided which determines whether the margin has become equal to or less than a predetermined judgment value within a predetermined period of time, and if it is determined that the margin has become equal to or less than the judgment value, makes a change to raise the lower limit of the predetermined threshold range, and if it is determined that the margin has not become equal to or less than the judgment value, lowers the lower limit of the predetermined threshold range.

[0038] This makes it easier to suppress hunting, which occurs when the predetermined temperature of hot and cold water is repeatedly changed to be increased and decreased. [Effects of the Invention]

[0039] According to the air conditioning system of the present invention, when the calculated margin exceeds a predetermined threshold range, the air conditioning capacity of the air conditioner is insufficient and the predetermined temperature of the cold and hot water is changed to relax the water supply temperature, thereby achieving the effect of making it easier to achieve both energy saving effects by relaxing the water supply temperature and preventing the deterioration of the thermal environment. [Brief explanation of the drawings]

[0040] [Figure 1] 1 is a schematic diagram illustrating an air conditioning system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram illustrating a configuration centered on an information processing unit in FIG. 1. [Figure 3] 1. FIG. 4 is a block diagram illustrating another configuration focusing on the information processing unit in FIG. [Figure 4] 1. FIG. 4 is a block diagram illustrating another configuration focusing on the information processing unit in FIG. [Figure 5] 1. FIG. 4 is a block diagram illustrating another configuration focusing on the information processing unit in FIG. [Figure 6] FIG. 10 is a block diagram illustrating a modified example of the embodiment focusing on an information processing unit. [Figure 7] FIG. 10 is a block diagram illustrating yet another modified example of the embodiment focusing on an information processing unit. DETAILED DESCRIPTION OF THE INVENTION

[0041] An air conditioning system 1 according to one embodiment of the present invention will be described with reference to Fig. 1 to Fig. 7. The air conditioning system 1 of this embodiment is a central heat source system. In the central heat source air conditioning system 1, cooling is performed using chilled water produced by a chiller 10, and heating is performed using hot water produced by the chiller 10.

[0042] As shown in FIG. 1, the air conditioning system 1 includes a refrigerator 10, a first water pump unit 20, an air conditioner 30, a valve unit 40, a second water pump unit 50, and an information processing unit 60.

[0043] The chiller 10 is configured to supply chilled water for cooling and hot water for heating. When there is no need to distinguish between chilled water and hot water, it is also referred to as chilled or hot water. The chiller 10 may be configured to supply only either chilled water or hot water. The chiller 10 is also configured to adjust the temperature of the chilled or hot water it supplies to a predetermined temperature, and is configured to be able to change the predetermined temperature.

[0044] The chiller 10 may be a heat pump or a chiller, and any known type of heat source machine can be used. In the air conditioning system 1 of this embodiment, two chillers 10 are arranged in parallel. The number of chillers 10 may be one or more than two.

[0045] The first water pump unit 20 has a configuration that sends out cold and hot water from the refrigerator 10 toward the air conditioner 30. The first water pump unit 20 has a configuration that allows the amount of water sent out per unit time to be changed.

[0046] The first water pump unit 20 of this embodiment has a configuration in which the amount of hot or cold water delivered is changed by changing the rotation frequency of the electric motor that drives the first water pump unit 20. The rotation frequency of the electric motor is also referred to as the pump frequency.

[0047] The rotation frequency of the electric motor may be changed by, for example, inverter control. When the rotation frequency of the electric motor is changed by inverter control, the rotation frequency is also referred to as the inverter frequency.

[0048] In the air conditioning system 1 of this embodiment, three first water pump units 20 are arranged in parallel. The number of first water pump units 20 may be less than three or more than three.

[0049] The pump frequency of the first water pump unit 20 may be proportionally controlled based on the difference between the target value (also referred to as SP) and the current value (also referred to as PV) of temperature and humidity in the target space. The target value may be a predetermined value or a value input by the user of the target space. The current value may be a value acquired from the pump measurement unit 21, which will be described later.

[0050] For example, when the demand for cooling or dehumidification increases (in other words, when the target value for the indoor temperature in the target space is lowered, or when the target value for the indoor humidity is lowered), the information processing unit 60 controls the opening of the valve 40 of the chilled water pipe connected to the air conditioner 30 for which the demand has increased so that the opening of the valve 40 of the chilled water pipe is increased. When the opening of the valve 40 of the chilled water pipe is increased, the flow rate of chilled water flowing to the air conditioner 30 for which the demand has increased increases.

[0051] When the opening of many of the valves 40 on the chilled water pipes increases and the chilled water supply pressure decreases, it is difficult to increase the flow rate of the chilled water even if the opening of the valves 40 on the chilled water pipes is further increased. In this case, the information processing unit 60 controls the first water supply pump unit 20 to increase the pump frequency. In other words, control is performed to increase the chilled water supply pressure. As the pump frequency increases, the flow rate of the chilled water sent out from the first water supply pump unit 20 increases. In other words, the flow rate of the chilled water flowing through the air conditioner 30 increases, and the air conditioning capacity of the air conditioner 30 increases.

[0052] 2, the first water pump unit 20 is provided with a pump measurement unit (corresponding to a measurement unit in the claims) 21 that measures the pump frequency, which is the first parameter. The pump measurement unit 21 is configured to measure the pump frequency. Information on the measured pump frequency is output from the pump measurement unit 21 to the information processing unit 60.

[0053] 1, a first header 71 is disposed between the first water pump unit 20 and the chillers 10. The first header 71 is connected to each of the two chillers 10 so that chilled or hot water can flow therethrough, and is connected to each of the three first water pump units 20 so that chilled or hot water can flow therethrough. The first header 71 is also connected to a third header 73, which will be described later, so that chilled or hot water can flow therethrough.

[0054] A second header 72 is disposed between the first water pump unit 20 and the air conditioner 30. The second header 72 is connected to each of the three first water pump units 20 so that cold and hot water can flow therethrough, and is connected to the air conditioner 30 so that cold and hot water can flow therethrough.

[0055] The air conditioner 30 is configured to receive a supply of hot and cold water to condition a target space. The target space includes indoor spaces such as offices, residences, and computer rooms. The air conditioner 30 of this embodiment may be an air handling unit (hereinafter also referred to as an AHU).

[0056] 1 is provided with three air conditioners 30. The number of air conditioners 30 provided in the air conditioning system 1 may be more or less than three. The three air conditioners 30 are connected to pipes that extend from the second header 72 and branch out in parallel.

[0057] The air conditioner 30 includes a heat exchanger that exchanges heat between a heat medium and indoor air, and a fan that draws air from the room and blows the air out into the room after heat exchange.

[0058] The air conditioner 30 may be an AHU, a fan coil unit (hereinafter also referred to as an FCU), or other equipment that exchanges heat between circulating hot and cold water and the air in the target space.

[0059] The valve unit 40 is configured to control the flow rate of chilled or hot water passing through the air conditioner 30. The valve unit 40 of this embodiment is configured to control the flow rate of chilled or hot water by changing the cross-sectional area of ​​the flow path through which the chilled or hot water flows.

[0060] The valve units 40 are arranged in a one-to-one correspondence with the air conditioners 30. Three valve units 40 are provided in the air conditioning system 1 shown in Fig. 1. In addition, in the air conditioning system 1 shown in Fig. 1, the valve units 40 are arranged downstream of the air conditioners 30 in the flow of hot and cold water.

[0061] 2, the valve section 40 is provided with a valve measurement section (corresponding to a measurement section in the claims) 41 that measures the opening degree, which is the first parameter. The valve section 40 has a configuration that measures the opening degree of the valve section 40. Information about the measured opening degree is output from the valve measurement section 41 to the information processing section 60.

[0062] 1, the second water pump unit 50 has a configuration for sending out hot and cold water flowing out from the air conditioner 30 to the refrigerator 10. The second water pump unit 50 may have a configuration in which the amount of water sent out per unit time is fixed, or may have a configuration in which the amount of water sent can be changed.

[0063] When the second water pump unit 50 is configured to be able to change the amount of water fed, the amount of hot or cold water fed can be changed by changing the rotation frequency of the motor that drives the second water pump unit 50, similar to the first water pump unit 20. The rotation frequency of the motor may be changed by, for example, inverter control.

[0064] The second water pump units 50 are arranged in a one-to-one correspondence with the chillers 10. The air conditioning system 1 shown in Fig. 1 is provided with two second water pump units 50. In the air conditioning system 1 shown in Fig. 1, the second water pump units 50 are arranged on the chilled / hot water suction side of the chillers 10.

[0065] A third header 73 is disposed between the valve unit 40 and the second water pump unit 50. The third header 73 is connected to the three valve units 40 so that hot and cold water can flow through them. The hot and cold water that has passed through each of the three valve units 40 joins together into one pipe and flows into the third header 73. The two second water pump units 50 are also connected to each other so that hot and cold water can flow through them. The first header 71 is also connected to each other so that hot and cold water can flow through them.

[0066] The information processing unit 60 is an information processing device configured to estimate a shortage of air conditioning capacity in the air conditioning system 1, and is an information processing device such as a personal computer or server having a CPU (central processing unit), ROM, RAM, input / output interface, etc.

[0067] The information processing unit 60 may be incorporated into a building energy management system (hereinafter also referred to as BEMS) or into a building automation system (hereinafter also referred to as BAS).

[0068] The program stored in the storage device such as the ROM described above causes the CPU, ROM, RAM, and input / output interface to function in cooperation as a calculation unit 61, a control unit 62, and a change unit 63, as shown in FIG. 2.

[0069] The calculation unit 61 has a configuration for calculating a margin parameter M of the air conditioning capacity of the air conditioner 30. The margin parameter M is calculated based on the first parameter and the second parameter. The specific calculation process for the calculation will be described later.

[0070] The control unit 62 has a configuration for performing control to change the air conditioning capacity of the air conditioner 30. The control is performed when the margin parameter M exceeds a predetermined threshold range. The control also performs control to change a predetermined temperature, which is the temperature of the chilled or hot water supplied to the chiller 10. The specific content of the control will be described later.

[0071] The change unit 63 has a configuration for changing the lower limit Mmin of a predetermined range of the margin parameter M. The change is made when a predetermined condition for changing the load on the air conditioner 30 is satisfied. The predetermined condition may be determined in advance. The specific content of the change will be described later.

[0072] Next, we will explain the air conditioning of the target space in the air conditioning system 1 having the above configuration. We will explain the case where the target space is cooled by the air conditioning system 1. Note that when the target space is heated by the air conditioning system 1, the difference is that the chilled / hot water generated by the refrigerator 10 is changed from chilled water to hot water, and other explanations are the same as when cooling, so explanations will be omitted.

[0073] During cooling, chilled water is produced by the chiller 10 in the air conditioning system 1. The chiller 10 produces chilled water at a predetermined temperature. Here, the predetermined temperature of the chilled water produced by the chiller 10 can be, for example, 7°C. Note that the predetermined temperature may be lower or higher than 7°C.

[0074] The chilled water generated in the chiller 10 flows from the chiller 10 into the first header 71. The chilled water that flows into the first header 71 is sucked into the three first water pump units 20. The first water pump units 20 send the chilled water toward the second header 72.

[0075] The pump frequency of the first water pump unit 20 may be proportionally controlled based on the difference between the target and current values ​​of temperature and humidity in the target space. The target value may be a predetermined value or may be a value input by a user of the target space. The current value may be a value acquired from the pump measurement unit 21.

[0076] For example, when the demand for cooling or dehumidification increases, the information processing unit 60 controls the opening of the valve 40 of the chilled water pipe connected to the air conditioner 30 for which the demand is increased so that the opening of the valve 40 of the chilled water pipe increases. When the opening of the valve 40 of the chilled water pipe increases, the flow rate of chilled water flowing to the air conditioner 30 for which the demand is increased increases.

[0077] When the opening of many of the valves 40 on the chilled water pipes increases and the chilled water supply pressure decreases, it is difficult to increase the flow rate of the chilled water even if the opening of the valves 40 on the chilled water pipes is further increased. In this case, the information processing unit 60 controls the first water supply pump unit 20 to increase the pump frequency. In other words, control is performed to increase the chilled water supply pressure. As the pump frequency increases, the flow rate of the chilled water sent out from the first water supply pump unit 20 increases. In other words, the flow rate of the chilled water flowing through the air conditioner 30 increases, and the air conditioning capacity of the air conditioner 30 increases.

[0078] Note that some of the chilled water that has flowed into the first header 71 may flow toward the third header 73. For example, if the flow rate of chilled water flowing into the first header 71 from the two chillers 10 is greater than the flow rate of chilled water sucked from the first header 71 into the three first water pump units 20, some of the chilled water that has flowed into the first header 71 will flow toward the third header 73.

[0079] The chilled water that flows into the second header 72 flows out from the second header 72 toward the air conditioners 30. The chilled water flows from one pipe extending from the second header 72 to three pipes extending to the three air conditioners 30, and flows into each of the three air conditioners 30.

[0080] In the air conditioner 30, heat exchange occurs between the incoming cold water and the air in the target space. The air in the target space is cooled by the cold water inside the air conditioner 30, and the cooled air is sent out to the outside of the air conditioner 30.

[0081] The cold water, whose temperature has increased by cooling the air in the target space, flows out from the air conditioner 30 toward the valve unit 40. The opening degree of the valve unit 40 may be proportionally controlled based on the difference between the target and current temperature and humidity values ​​in the target space. For example, when the demand for cooling or dehumidification increases, the information processing unit 60 controls the valve unit 40 to open more. As the opening degree increases, the flow rate of chilled water flowing through the valve unit 40 increases. In other words, the flow rate of chilled water flowing through the air conditioner 30 increases, and the air conditioning capacity of the air conditioner 30 increases.

[0082] The chilled water that has passed through the valve unit 40 flows toward the third header 73. The chilled water that has flowed into the third header 73 is sucked from the third header 73 into the two second water supply pump units 50. The second water supply pump units 50 send out the chilled water toward the chiller 10. The chiller 10 cools the chilled water, whose temperature has risen due to heat exchange in the air conditioner 30, to a predetermined temperature and sends it out again toward the first header 71.

[0083] Note that some of the chilled water that has flowed into the third header 73 may flow toward the first header 71. For example, if the flow rate of chilled water flowing into the third header 73 from the three air conditioners 30 is greater than the flow rate of chilled water sucked from the third header 73 into the two second water pump units 50, some of the chilled water that has flowed into the third header 73 will flow toward the first header 71.

[0084] Next, we will explain the details of the processing performed by the information processing unit 60 in the air conditioning system 1 having the above configuration. Specifically, we will explain the processing for estimating a shortage of air conditioning capacity in the air conditioner 30 and the control of the air conditioning system 1 based on the estimation.

[0085] The information processing unit 60 repeatedly performs the calculation process described below at predetermined timings, which are set at regular intervals, for example, every 30 minutes.

[0086] The calculation unit 61 of the information processing unit 60 performs processing to calculate a margin parameter M of the air conditioning capacity of the air conditioner 30. The margin parameter M is calculated for each of the multiple air conditioners 30. The margin parameter M is calculated based on, for example, the following formula (1).

[0087]

number

[0088] Here, Rp is the value obtained by dividing the pump frequency of the first water pump unit 20 by the maximum pump frequency. Rv is the value obtained by dividing the opening of the valve unit 40 by the maximum opening. Here, the maximum pump frequency is the maximum value of the pump frequency in the first water pump unit 20 (the second parameter in the claims), and is a value stored in advance in the information processing unit 60. Also, the maximum opening is the maximum value of the opening in the valve unit 40 (the second parameter in the claims), and is a value stored in advance in the information processing unit 60.

[0089] The margin parameter M is a value ranging from 0 to 1. As the margin parameter M approaches 0, the margin of the air conditioning capacity of the air conditioner 30 decreases. On the other hand, as the margin parameter M approaches 1, the margin of the air conditioning capacity of the air conditioner 30 increases.

[0090] The margin parameter M approaching 0 indicates that the pump frequency of the first water pump unit 20 approaches the maximum pump frequency and that the opening of the valve unit 40 approaches the maximum opening.

[0091] For example, if the valve unit 40 is at its maximum opening during cooling, it can be said that the air conditioner 30 is performing at its maximum capacity at the current chilled water temperature and pump frequency of the first water pump unit 20. In this case, to increase the air conditioning capacity of the air conditioner 30, the pump frequency of the first water pump unit 20 is increased, and control is performed to increase the flow rate of chilled water.

[0092] However, if the pump frequency of the first water supply pump unit 20 reaches the maximum pump frequency, it is impossible to expect an increase in air conditioning capacity at the temperature of the chilled water at that time, and it can be determined that there is a high possibility of insufficient cooling capacity.

[0093] The pump frequency of the first water supply pump unit 20 and the opening degree of the valve unit 40 vary according to the operating conditions of the air conditioning system 1. Therefore, the value of the margin parameter M also varies according to the operating conditions. The calculation unit 61 may obtain a moving average value of the margin parameter M based on a plurality of margin parameters M obtained at predetermined timings. The moving average value of the margin parameter M is obtained for each of the plurality of air conditioners 30.

[0094] When the margin parameter M is obtained for each of the plurality of air conditioners 30, the control unit 62 performs control to change the air conditioning capacity of the air conditioner 30. The control to change the air conditioning capacity is performed based on the margin parameter Mb with the smallest value among the plurality of margin parameters M.

[0095] The control unit 62 performs control to change the air conditioning capacity when the margin parameter Mb exceeds a predetermined threshold range. The predetermined threshold range is a range where the lower limit is not less than Mmin and the upper limit is not more than Mmax. The upper limit Mmax is a value obtained by adding a predetermined value Diff to the lower limit Mmin (Mmax = Mmin + Diff).

[0096] In the case of cooling operation, when the margin parameter Mb is less than the lower limit Mmin (Mb < Mmin), the control unit 62 performs control to change the predetermined temperature of the chilled water supplied to the chiller 10 to a temperature decreased by dt °C. That is, when there is a high possibility that the air conditioning capacity of the air conditioner 30 is insufficient, the control unit 62 performs control to lower the predetermined temperature of the supplied chilled water.

[0097] Furthermore, when the margin parameter Mb is equal to or greater than the upper limit Mmax (Mmax≦Mb), the control unit 62 performs control to change the predetermined temperature of the chilled water to be supplied to the chiller 10 to a temperature increased by dt°C. In other words, when there is a margin in the air conditioning capacity of the air conditioner 30, the control unit 62 performs control to increase the predetermined temperature of the chilled water to be supplied. Note that the temperature difference dt°C when decreasing the predetermined temperature of the chilled water and the temperature difference dt°C when increasing the predetermined temperature of the chilled water may be the same value or different values.

[0098] The values ​​of Mmin, Diff, Mmax, and dt are set based on the response characteristics of the air conditioning system 1. For example, Mmin may be set to 5%, Diff to 10%, Mmax to 15%, and dt to 0.5°C.

[0099] It is preferable to set a certain interval (Diff) between Mmax and Mmin. Diff is preferably small enough to prevent hunting, which is the repeated control of increasing and decreasing the predetermined temperature of cold water.

[0100] Next, we will explain the process of changing the lower limit Mmin of the predetermined threshold range in the air conditioning system 1 having the above configuration. The process of changing the lower limit Mmin is performed by the change unit 63. The change process is performed when the load on the air conditioner 30 changes, for example, when the weather changes or when the way the room, which is the target space, is used changes.

[0101] The change unit 63 performs a process of storing the value of the lower limit Mmin and the value of the margin parameter Mb. Next, the change unit 63 performs a process of comparing the stored value of the margin parameter Mb with a judgment value that is a predetermined condition.

[0102] In this embodiment, the determination value is 0, and processing is performed to determine whether the value of the margin parameter Mb is equal to or less than the determination value. In other words, processing is performed to determine whether the air conditioning capacity of the air conditioner 30 is insufficient.

[0103] If it is determined that the value of the margin parameter Mb is equal to or less than the determination value, the change unit 63 performs processing to increase the value of the lower limit Mmin. In other words, processing to increase the margin of the air conditioning capacity of the air conditioner 30 is performed.

[0104] Furthermore, if it is determined that the value of the margin parameter Mb is not equal to or less than the determination value, a process is performed to reduce the value of the lower limit Mmin. In other words, a process is performed to facilitate reducing the amount of energy consumed when supplying cold or hot water. The determination value may be 0 or a value other than 0.

[0105] The stored value of the margin parameter Mb may be a value obtained within a predetermined period of time after the lower limit Mmin is set. The predetermined period of time may be the period from when the set temperature of chilled or hot water is changed until the temperature of chilled or hot water flowing into the air conditioner 30 reaches the changed set temperature. For example, the predetermined period of time may be several minutes to several tens of minutes.

[0106] According to the air conditioning system 1 configured as described above, when the calculated margin parameter M exceeds a predetermined threshold range, the predetermined temperature of the chilled or hot water is changed to moderate the supply water temperature. For example, when the margin parameter M is greater than the predetermined threshold range, the chilled water temperature is changed to a value that reduces the air conditioning capacity of the air conditioner 30. This makes it easier to reduce the amount of energy consumed when supplying chilled or hot water, and makes it easier to ensure energy-saving effects by moderating the supply water temperature.

[0107] Furthermore, when the margin parameter M is a value smaller than a predetermined threshold range, the chilled water temperature is changed to increase the air conditioning capacity of the air conditioner 30. This makes it easier to ensure the air conditioning capacity of the air conditioner 30 and makes it easier to prevent the thermal environment from deteriorating due to relaxation of the water supply temperature.

[0108] The margin parameter M is calculated based on the first parameters measured by the pump measurement unit 21 and the valve measurement unit 41. Therefore, compared to an analysis performed by a specialized company, it is easier to grasp a shortage of the air conditioning capacity of the air conditioner 30 at an early stage and to avoid the shortage of air conditioning capacity at an early stage.

[0109] Furthermore, by controlling using the margin parameter M based on the first parameter, it becomes easier to reduce the safety margin in the temperature mitigation range and implementation period compared to control using analysis performed by a specialized company. As a result, it becomes easier to ensure energy-saving effects by mitigating the water supply temperature.

[0110] It is possible to disclose to tenants the margin parameter M before control and the margin parameter M after control. By disclosing such margin parameter M, it becomes possible to quantitatively explain the energy-saving effect and thermal environment of the target space.

[0111] By changing the lower limit of the predetermined threshold range when the load on the air conditioner 30 changes, it becomes easier to further reduce the amount of energy consumed when supplying hot or cold water, and it becomes easier to ensure energy saving effects by mitigating the water supply temperature. Changes in the load on the air conditioner 30 include, for example, changes in the weather, changes in the way the room, which is the target space, is used, etc.

[0112] By performing control based on the margin parameter Mb, which has the smallest value among the multiple margin parameters M, it becomes less likely that the margin parameter M will have a value smaller than a predetermined threshold range. In other words, it becomes less likely that the air conditioner 30 will have insufficient air conditioning capacity, making it easier to prevent the thermal environment from deteriorating due to relaxation of the water supply temperature.

[0113] This makes it easier to suppress hunting, which occurs when the predetermined temperature of hot and cold water is repeatedly changed to be increased and decreased.

[0114] The margin parameter M may be calculated based on the following equation (2) instead of the above equation (1).

[0115]

number

[0116] Here, Qp is the air conditioning capacity of the air conditioner 30. Qmax is the maximum air conditioning capacity of the air conditioner 30 for the supplied hot and cold water (the second parameter in the claims), and is a value stored in advance in the information processing unit 60.

[0117] Qp may be calculated based on the inlet / outlet temperature difference of the chilled / hot water in the air conditioner 30 and the flow rate of the chilled / hot water in the air conditioner 30 using the following formula (3).

[0118]

number

[0119] Here, Cw is the specific heat of the chilled / hot water, Vw is the flow rate of the chilled / hot water in the air conditioner 30, Two is the outlet temperature of the chilled / hot water in the air conditioner 30, and Twi is the inlet temperature of the chilled / hot water in the air conditioner 30.

[0120] In this case, the air conditioner 30 is provided with a flow rate measuring unit (corresponding to the measuring unit in the claims) 31a, an outlet temperature measuring unit (corresponding to the measuring unit in the claims) 32a, and an inlet temperature measuring unit (corresponding to the measuring unit in the claims) 33a, as shown in FIG.

[0121] The flow rate measuring unit 31a is configured to measure the first parameter, that is, the flow rate Vw of chilled or hot water flowing through the air conditioner 30. Information on the measured flow rate Vw of chilled or hot water is output from the flow rate measuring unit 31a to the information processing unit 60.

[0122] The outlet temperature measurement unit 32a is configured to measure the first parameter, that is, the temperature Two of the chilled or hot water flowing out from the air conditioner 30. Information on the measured temperature Two of the chilled or hot water is output from the outlet temperature measurement unit 32a to the information processing unit 60.

[0123] The inlet temperature measuring unit 33a is configured to measure the first parameter, which is the temperature Twi of the cold or hot water flowing into the air conditioner 30. Information on the measured temperature Twi of the cold or hot water is output from the inlet temperature measuring unit 33a to the information processing unit 60.

[0124] Qp may be calculated using the above formula (3) based on the temperature difference between the inlet and outlet of the chilled / hot water in the chiller 10 and the flow rate of the chilled / hot water in the chiller 10. In this case, Vw in formula (3) is the flow rate of the chilled / hot water in the chiller 10, Two is the outlet temperature of the chilled / hot water in the chiller 10, and Twi is the inlet temperature of the chilled / hot water in the chiller 10.

[0125] Alternatively, Qp may be calculated using the following formula (4) based on the airflow rate and the enthalpy difference between the inlet and outlet of the air. The airflow rate may be estimated from the fan inverter frequency value based on the characteristic data of the air conditioner 30.

[0126]

number

[0127] Here, Va is the volumetric airflow rate in the air conditioner 30, h is the specific volume of air, Hao is the enthalpy of the air blown out from the air conditioner 30, and Hai is the enthalpy of the air drawn in from the air conditioner 30.

[0128] In this case, the air conditioner 30 is provided with an air volume measuring unit (corresponding to the measuring unit in the claims) 31b, a blowing enthalpy measuring unit (corresponding to the measuring unit in the claims) 32b, and an intake enthalpy measuring unit (corresponding to the measuring unit in the claims) 33b, as shown in FIG.

[0129] The air volume measurement unit 31b is configured to measure the first parameter, ie, the volumetric air volume Va, in the air conditioner 30. Information on the measured volumetric air volume Va is output from the air volume measurement unit 31b to the information processing unit 60.

[0130] The blowout enthalpy measuring unit 32b has a configuration that measures the blowout air enthalpy Hao, which is the first parameter, in the air conditioner 30. Information on the measured blowout air enthalpy Hao is output from the blowout enthalpy measuring unit 32b to the information processing unit 60.

[0131] The suction enthalpy measuring unit 33b has a configuration that measures the suction air enthalpy Hai, which is the first parameter, in the air conditioner 30. Information on the measured suction air enthalpy Hai is output from the suction enthalpy measuring unit 33b to the information processing unit 60.

[0132] Furthermore, when the air conditioner 30 is a dry coil, or when it is assumed to be a pseudo-dry coil, Qp may be calculated based on the following formula (5).

[0133]

number

[0134] Here, Ca is the specific heat of air, Tao is the temperature of air blown out from the air conditioner 30, and Tai is the temperature of air suctioned from the air conditioner 30.

[0135] In this case, the air conditioner 30 is provided with an air volume measurement unit 31b, a blow-out temperature measurement unit (corresponding to the measurement unit in the claims) 32c, and an intake temperature measurement unit (corresponding to the measurement unit in the claims) 33c, as shown in FIG.

[0136] The blown air temperature measuring unit 32c is configured to measure the blown air temperature Tao, which is the first parameter, in the air conditioner 30. Information on the measured blown air temperature Tao is output from the blown air temperature measuring unit 32c to the information processing unit 60.

[0137] The intake temperature measuring unit 33c is configured to measure the intake air temperature Tai, which is the first parameter, in the air conditioner 30. Information on the measured intake air temperature Tai is output from the intake temperature measuring unit 33c to the information processing unit 60.

[0138] The control unit 62 may perform control to change the air conditioning capacity based on the margin parameter Mb, which has the smallest value among the multiple margin parameters M, as described above, that is, control to change the specified temperature of the chilled or hot water, or, when multiple air conditioners 30 perform air conditioning on the same target space, may perform the control described below.

[0139] Even if some of the margin parameters M of each of the multiple air conditioners 30 exceed the predetermined threshold range, if the remaining margin parameters M do not exceed the predetermined threshold range, the control unit 62 does not need to perform control to change the predetermined temperature of the cold or hot water.

[0140] For example, even if the margin parameter M of one air conditioner 30 is a value of 0 that exceeds the predetermined threshold range, if the margin parameters M of the remaining air conditioners 30 do not exceed the predetermined threshold range and there is margin in the air conditioning capacity, the control unit 62 does not need to perform control to change the predetermined temperature of the hot and cold water.

[0141] By doing this, even if the margin parameter M is smaller than the predetermined threshold range and an air conditioner 30 with insufficient air conditioning capacity is generated, there will still be air conditioners 30 with surplus air conditioning capacity among the multiple air conditioners 30 that perform air conditioning for the same target space. Therefore, the air conditioners 30 with surplus air conditioning capacity can compensate for the air conditioners 30 with insufficient capacity, making it easier to prevent deterioration of the thermal environment in the target space.

[0142] In addition, when multiple air conditioners 30 perform air conditioning on a target space that satisfies predetermined conditions regarding temperature difference, the control unit 62 may perform control to change the air conditioning capacity based on the group margin parameter Mg described below, that is, control to change the predetermined temperature of the chilled or hot water.

[0143] The specified conditions regarding temperature difference include a condition in which the temperature difference between various locations in the target space is below a specified threshold, and a condition in which measures are taken to mix the air, such as circulating the air within the target space.

[0144] An example of a predetermined threshold value for the temperature difference (corresponding to a predetermined value) is the sum of the value of the mutual measurement error between multiple temperature sensors used to control the air conditioner and the value of the temperature difference that causes a person to perceive a difference in thermal sensation.

[0145] For example, when trying to achieve a uniform thermal environment within the same target space, the same target temperature is set for multiple air conditioners (e.g., an intake temperature of 26°C). In this case, a certain error (e.g., about ±0.5°C) is allowed for the temperature sensors used to control the air conditioning. When multiple temperature sensors are used, a measurement error of about twice the maximum allowable error (e.g., about 1°C) may occur between the multiple temperature sensors.

[0146] The temperature difference that causes a difference in human thermal sensation is thought to be, for example, about 1° C. Therefore, the predetermined value of the temperature difference is thought to be, for example, about 2° C.

[0147] When the predetermined condition regarding the temperature difference is satisfied, the control unit 62 performs processing to calculate the group margin parameter Mg based on the following equation (6). The group margin parameter Mg may be an average value using a predetermined coefficient. The predetermined coefficient may be the rated cooling capacity Q of the air conditioner 30.

[0148]

number

[0149] Here, Qn is the rated cooling capacity of each of the air conditioners 30, and Mn is the margin parameter of each of the air conditioners 30.

[0150] When the control unit 62 calculates the group margin parameter Mg, it performs control based on the group margin parameter Mg instead of the margin parameter M. For example, when the group margin parameter Mg exceeds a predetermined threshold range, it controls the chiller 10 to change the predetermined temperature of the chilled or hot water.

[0151] By using the group margin parameter Mg in this way, it is possible to handle and control a plurality of air conditioners 30 relating to a target space that satisfies predetermined conditions as a single unit.

[0152] The change unit 63 may perform processing to change the lower limit Mmin of the predetermined range of the margin parameter M based on the air conditioning load parameter La related to the load of the air conditioner 30. In this case, as shown in Fig. 6, the air conditioning system 1 is further provided with a load measurement unit 35 that measures the air conditioning load parameter La.

[0153] The load measurement unit 35 includes a sensor that measures the indoor temperature, which is the temperature of the target space. It may also include a human presence sensor that detects the presence or absence of a person in the target space, a sensor that measures the outside air temperature, which is the temperature outside the target space, or a sensor that detects the outside weather.

[0154] The change unit 63 performs a process of determining whether the amount of change in the air conditioning load parameter La measured by the load measurement unit 35 has become equal to or greater than a judgment value over a predetermined period of time. If it is determined that the amount of change has become equal to or greater than the judgment value, the change unit 63 performs a process of changing the lower limit Mmin of a predetermined range of the margin parameter M.

[0155] For example, if the change in the air conditioning load parameter La indicates an increase in the air conditioning load in the air conditioner 30, the value of the lower limit Mmin is changed to a larger value. Conversely, if the change in the air conditioning load parameter La indicates a decrease in the air conditioning load in the air conditioner 30, the value of the lower limit Mmin is changed to a smaller value.

[0156] The predetermined period can be any predetermined period of time. The predetermined period may be a period that takes into account the rate at which the air conditioning load in the air conditioner 30 changes. For example, the predetermined period can be the period from when the predetermined temperature of the chilled or hot water is changed until the chilled or hot water at the changed temperature reaches the air conditioner. Specifically, the predetermined period can be a period of several minutes to several tens of minutes.

[0157] Any predetermined value can be used as the judgment value for the amount of change in the air conditioning load parameter La. The judgment value may take into consideration the degree of allowable insufficiency in the air conditioning capacity of the air conditioner 30.

[0158] Changing the lower limit Mmin of the threshold range based on the air conditioning load parameter La makes it easier to increase the energy saving effect of the air conditioner 30 and to reduce the risk of insufficient air conditioning capacity in the air conditioner 30. For example, the smaller the lower limit Mmin of the threshold range is set, the higher the energy saving effect becomes, and the larger the lower limit Mmin of the threshold range is set, the lower the risk of insufficient air conditioning capacity becomes.

[0159] By changing the lower limit Mmin of the value range based on the results of comparing the change in the air conditioning load parameter La over a specified period with the judgment value, for example, if the specified temperature of cold or hot water is changed, the lower limit Mmin of the threshold range can be changed based on the changed specified temperature.

[0160] Furthermore, the change unit 63 may perform processing to change the lower limit Mmin of the predetermined range of the margin parameter M based on the prediction parameter Lp which is based on the air conditioning load parameter La. In this case, as shown in Fig. 7, a program stored in the storage device such as the ROM in the information processing unit 60 causes the CPU, ROM, RAM, and input / output interface to cooperate with each other and function as a calculation unit 61, a control unit 62, a change unit 63, and a prediction unit 65, as shown in Fig. 6.

[0161] The prediction unit 65 is configured to predict a prediction parameter Lp. The prediction parameter Lp is the air conditioning load parameter La after a predetermined time lag. The time lag can be 30 minutes, 1 hour, or the like.

[0162] A prediction method using machine learning can be used as a method for predicting the predicted parameter Lp based on the air conditioning load parameter La. For example, a learning model can be trained using past air conditioning load parameters La that have been stored and accumulated in advance in the information processing unit 60 and data on the actual load values ​​of the air conditioners 30 linked to the air conditioning load parameters La, and the measured air conditioning load parameters La can be input into the trained learning model to determine the predicted parameter Lp.

[0163] The prediction unit 65 performs a process of determining whether the value of the predicted prediction parameter Lp has increased or decreased. If it is determined that the value of the prediction parameter Lp has increased or decreased, the prediction unit 65 performs a process of changing the lower limit Mmin of the predetermined range of the margin parameter M.

[0164] For example, if the value of the prediction parameter Lp increases, indicating an increase in the air conditioning load in the air conditioner 30, the value of the lower limit Mmin is changed to a larger value. Conversely, if the value of the prediction parameter Lp decreases, indicating a decrease in the air conditioning load in the air conditioner 30, the value of the lower limit Mmin is changed to a smaller value.

[0165] By changing the lower limit Mmin of the threshold range based on the increase or decrease in the prediction parameter Lp, it becomes easier to further increase the energy-saving effect of the air conditioner 30 and to further reduce the risk of insufficient air conditioning capacity in the air conditioner 30 compared to when the prediction parameter Lp is not used.

[0166] For example, if the load on the air conditioner 30 is expected to decrease after a time lag, the lower limit Mmin of the threshold range is changed to enhance the energy-saving effect of the air conditioner 30. Also, if the load on the air conditioner 30 is expected to increase after a time lag, the lower limit Mmin of the threshold range is changed to reduce the risk of insufficient air conditioning capacity in the air conditioner 30.

[0167] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the present invention is not limited to applications of the above-described embodiments, and may be applied to embodiments in which these embodiments are appropriately combined, and is not particularly limited. [Explanation of symbols]

[0168] 1...air conditioning system, 10...refrigeration unit, 21...pump measurement unit, 30...air conditioner, 31a...flow rate measurement unit, 31b...air flow rate measurement unit, 32a...outlet temperature measurement unit, 32b...discharge enthalpy measurement unit, 32c...discharge temperature measurement unit, 33a...inlet temperature measurement unit, 33b...suction enthalpy measurement unit, 33c...suction temperature measurement unit, 41...valve measurement unit, 61...calculation unit, 62...control unit, 63...change unit, 65...prediction unit, M...margin parameter, Mg...group margin parameter, La...air conditioning load parameter, Lp...prediction parameter

Claims

1. a refrigerator that supplies hot and cold water at a predetermined temperature; an air conditioner that receives the supply of cold and hot water and conditions the air in a target space; a measurement unit that measures a first parameter related to the air conditioning capacity of the air conditioner; a calculation unit that calculates a margin of air conditioning capacity based on the first parameter and a second parameter related to a maximum air conditioning capacity of the air conditioner when the supplied chilled or hot water is used; a control unit that, when the margin exceeds a predetermined threshold range, controls the refrigerator to lower the predetermined temperature of the chilled water or raise the predetermined temperature of the hot water when the margin falls below a lower limit of the threshold range, and controls the refrigerator to raise the predetermined temperature of the chilled water or lower the predetermined temperature of the hot water when the margin exceeds an upper limit of the threshold range, thereby changing the air conditioning capacity of the air conditioner; a change unit that changes the lower limit of the predetermined threshold range by increasing the lower limit when it is determined that the margin has fallen below the predetermined condition, where the load on the air conditioner changes, and that changes the lower limit of the predetermined threshold range by decreasing the lower limit when it is determined that the margin has not fallen below the predetermined condition; Equipped with an air conditioning system.

2. a load measurement unit for measuring an air conditioning load parameter related to the load of the air conditioner is further provided, The air conditioning system according to claim 1 , wherein the change unit changes the lower limit of the threshold range when an amount of change in the air conditioning load parameter during a change period becomes equal to or greater than a determination value.

3. a prediction unit is further provided that predicts a prediction parameter that is the air conditioning load parameter after a predetermined time lag; The air conditioning system according to claim 2 , wherein the change unit changes the lower limit of the threshold range based on an increase or decrease in a prediction parameter with respect to the air conditioning load parameter.

4. the calculation unit calculates the margin for each of the plurality of air conditioners, The air conditioning system according to claim 1 , wherein the control unit performs control based on the smallest margin among the plurality of margins.

5. An air conditioning system as described in any one of claims 1 to 3, wherein the control unit does not perform control to change the specified temperature even if some of the multiple margins related to multiple air conditioners that perform air conditioning on the same target space exceed the specified threshold range, if the remaining margins do not exceed the specified threshold range.

6. the calculation unit calculates a group margin, which is an average value using a predetermined coefficient, based on the margins for the plurality of air conditioners that perform air conditioning on the target space that satisfy a predetermined condition related to a temperature difference; The air conditioning system according to any one of claims 1 to 3, wherein the control unit controls the refrigerator to change the predetermined temperature when the group margin exceeds the predetermined threshold range instead of the margin.

7. The air conditioning system of any one of claims 1 to 3, wherein the change unit determines whether the margin of safety has become equal to or less than a predetermined judgment value within a predetermined period of time, and if it is determined that the margin of safety has become equal to or less than the judgment value, makes a change to raise the lower limit of the predetermined threshold range, and if it is determined that the margin of safety has not become equal to or less than the judgment value, lowers the lower limit of the predetermined threshold range.

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