JP6001375B2 - Air conditioning system - Google Patents

Description

  The present invention relates to an air conditioning system including a plurality of chillers as a heat source.

  In the data center, a large number of electronic devices such as IT (information technology) devices and ICT (information communication technology) devices are arranged on the floor, and a large amount of heat generated from these electronic devices is generated. A processing air conditioning system is used.

  As this air conditioning system, one provided with an AHU (air handling unit) arranged in the floor and a plurality of chillers arranged outside the floor (eg outside the data center) is known (for example, , See Patent Document 1). AHU cools air in a floor whose temperature has been increased by heat generated by an electronic device using cold water supplied from a chiller. The air that has been cooled to lower the temperature takes heat generated from the electronic device and cools the electronic device. On the other hand, the cold water whose temperature has been increased by absorbing heat from the air in the floor is cooled by a plurality of air-cooled chillers and supplied to the AHU again. In the chiller, the heat absorbed by the cold water is released to the outside air.

JP 2012-078056 A

  In an air conditioning system provided with a plurality of chillers, each chiller supplies cold water at a flow rate required by the AHU, and control is performed to keep the cold water delivered at a predetermined temperature. However, in the above-described control, the efficiency depends on the operation state of each chiller, and when considered as a plurality of chillers as a whole (hereinafter referred to as “group”), there is a problem that the operation cannot always be performed with high efficiency. .

  In other words, in a state where a group of chillers are densely arranged, even if the same operation control is performed for all chillers, the ease of inhaling outdoor air and the temperature of the outdoor air to be inhaled vary due to interference between chillers. As a result, the efficiency of each chiller varies. In order to increase the efficiency of the group of chillers, it is desirable to keep the condensers provided in all the chillers working.

  However, if there is variation in the efficiency of each chiller, there is a possibility that some chillers stop and all the condensers are not working, and it is difficult to increase the efficiency as a group of chillers There was a problem.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide an air conditioning system capable of improving the efficiency of the entire system in an air conditioning system including a plurality of chillers. .

In order to achieve the above object, the present invention provides the following means.
The air conditioning system of the present invention includes a plurality of heat sources that are installed outdoors to supply cold water of a predetermined temperature, an air conditioner that cools indoor air using the cold water that is installed and supplied indoors, and a plurality of the heat sources. And an integrated control unit that controls the amount of cold water supplied from each and the start and stop of the heat source, and the heat source compresses the gas refrigerant to a high pressure and the high-pressure gas refrigerant A condenser for condensing the gaseous refrigerant to form a liquid refrigerant by releasing the heat of the liquid into the outdoor air, an expansion valve for expanding the high-pressure liquid refrigerant to a low pressure, and taking the heat from the cold water to reduce the low-pressure An evaporator that evaporates liquid refrigerant, a cold water pump unit that supplies the cold water to the air conditioner, and an individual control unit that controls at least the compressor so that the cold water supplied to the air conditioner maintains the predetermined temperature. Is equipped with In the air conditioning system, each of the plurality of heat sources is provided with a measurement unit that measures an index related to efficiency in the heat source, and the integrated control unit is based on the index output from the measurement unit, The flow rate increasing process for increasing the flow rate of the cold water sent from the cold water pump unit provided in the heat source having the highest efficiency, and the flow rate of the cold water sent from the cold water pump unit provided in the heat source having the lowest efficiency. And a flow rate reduction process to reduce.

  According to the air conditioning system of the present invention, by reducing the heat load on the heat source with the lowest efficiency and increasing the heat load on the heat source with the highest efficiency, variation in efficiency among the plurality of heat sources can be suppressed, and the air conditioning system as a whole. The efficiency can be improved. In other words, by reducing the flow rate of the chilled water sent from the chilled water pump unit provided in the heat source with the lowest efficiency, the amount of heat taken from the chilled water in the evaporator can be reduced, and the heat load on the heat source can be reduced. Lowering is suppressed.

  This decrease in the chilled water flow rate corresponds to an increase in the flow rate of chilled water sent from the chilled water pump unit provided in the heat source with the highest efficiency, and the chilled water at the required flow rate is supplied to the air conditioner as a whole. . After increasing the chilled water flow rate sent from the chilled water pump unit installed in the heat source with the highest efficiency, the flow rate increase processing and flow rate are reduced by reducing the chilled water flow rate sent out from the chilled water pump unit installed in the heat source with the lowest efficiency. Insufficient chilled water flow rate can be suppressed during the transitional period of reduction treatment.

  Further, by increasing the flow rate of the cold water in the heat source having the highest efficiency, the amount of heat taken from the cold water in the evaporator increases, and the heat load on the heat source increases. Therefore, the efficiency in the heat source is slightly lowered, and variation in efficiency among the plurality of heat sources is suppressed.

  In the above invention, a request flow rate that is a flow rate of the cold water required by the air conditioner is input to the integrated control unit, and the integrated control unit is a total flow rate of the cold water supplied from the plurality of chillers. A comparison process for comparing the supply flow rate with the required flow rate is performed, and when the required flow rate is larger than the supply flow rate, the flow rate of the cold water increased in the flow rate increase process is reduced by the flow rate reduction process. When the flow rate is larger than the flow rate of the cold water and the required flow rate is smaller than the supply flow rate, the flow rate of the cold water that is increased in the flow rate increase process is smaller than the flow rate of the cold water that is decreased in the flow rate decrease process. When the required flow rate is equal to the supply flow rate, the flow rate of the cold water increased in the flow rate increase process is equal to the flow rate of the cold water reduced in the flow rate decrease process. Rukoto is preferable.

  In this way, the comparison process comparing the supply flow rate and the required flow rate is performed, and the supply amount is adjusted by adjusting the flow rate increase amount of the cold water in the flow rate increase process and the flow rate decrease amount of the cold water in the flow rate reduction process based on the comparison result The flow rate and the required flow rate can be made equal. For example, in the flow rate reduction process performed after the flow rate increase process, the supply flow rate tends to be equal to the required flow rate by adjusting the flow rate decrease amount of the cold water.

  In the above invention, when the required flow rate is larger than the supply flow rate in the comparison process, when the heat source and the cold water pump unit that are stopped exist, the integrated control unit It is preferable to perform a startup process for operating the cold water pump unit, and then perform the flow rate increase process and the flow rate decrease process.

  Before the flow rate increasing process and the flow rate decreasing process are performed in this way, the stopped heat source and the cold water pump unit are started, and all the heat sources and the cold water pump unit are operated, thereby improving the efficiency of the entire air conditioning system. Can be planned. In other words, by operating all the heat sources and chilled water pump units, the area of the evaporator and condenser that can be used in the air conditioning system can be maximized, compared to the case where the area of the evaporator and condenser that can be used is small. The efficiency of the entire air conditioning system can be improved.

  In the said invention, the said integrated control part does not perform the said start process, when the total operation time of the said heat source and the said cold water pump part which are stopped is longer than the said other heat source and the said cold water pump part. It is preferable to perform the flow rate increasing process and the flow rate decreasing process.

  When the total operation time of the heat source and the chilled water pump unit stopped in this way is long, the heat source and the chilled water pump are performed by performing the flow rate increasing process and the flow rate decreasing process only for the other heat sources and the chilled water pump unit. Leveling of the operation time (particularly, the operation time of the compressor of the heat source) is facilitated.

  In the above invention, the integrated control unit is configured such that the total operation time of the stopped heat source and the cold water pump unit is longer than that of the other heat source and the cold water pump unit, and the temperature of the outdoor air is equal to or lower than a startup threshold. In this case, it is preferable to perform the flow rate increasing process and the flow rate decreasing process without performing the startup process.

  Thus, only when the temperature of the outdoor air further satisfies the condition below the start threshold, the heat source and the chilled water pump unit are operated by performing the flow rate increasing process and the flow rate decreasing process only for the other heat source and the chilled water pump unit. It is possible to balance the leveling of time (particularly the operation time of the compressor of the heat source) and the improvement of the efficiency of the entire air conditioning system.

  In the above invention, when the flow rate of the chilled water sent from the chilled water pump unit provided in the heat source having the highest efficiency in the flow rate increasing process has reached a predetermined upper limit, It is preferable to increase the flow rate of the cold water sent out from the cold water pump unit provided in the heat source having high efficiency.

  For the chilled water pump unit provided in the heat source having the highest efficiency as described above, when the flow rate of the chilled water to be sent cannot be increased any more, the chilled water sent out to the chilled water pump unit provided in the next most efficient heat source. By performing the control to increase the flow rate of the air conditioning system, it becomes easy to suppress the shortage of the cold water flow rate as the entire air conditioning system.

  In the above invention, the heat source is further provided with a watering device for sprinkling water into the condenser, and the integrated control unit is configured to supply water to the heat source and the cold water pump unit from which water is sprayed. It is preferable not to perform the flow rate increasing process and the flow rate decreasing process.

  Thus, the increase in running cost of the air conditioning system can be suppressed by performing the flow rate increasing process and the flow rate decreasing process except for the heat source and the cold water pump unit that perform the watering process.

  Generally, when watering treatment is performed, the cost of water to be sprinkled (for example, a water charge) is generated. Therefore, in order to suppress an increase in running cost, it is preferable to shorten the period of watering treatment.

  However, if the flow rate increasing process and the flow rate decreasing process are also performed for the heat source and the cold water pump unit that perform the watering process, the watering process cannot be completed because the load is more concentrated compared to other heat sources. The processing period tends to be long. Therefore, it is possible to suppress an increase in running cost of the air conditioning system by excluding the heat source and the cold water pump unit that perform the watering treatment from the target of the flow rate increasing process and the flow rate decreasing process.

  In the above invention, when the difference between the maximum index and the minimum index among the indexes output from the plurality of measurement units is equal to or greater than a predetermined index threshold, the integrated control unit It is preferable to perform an increase process.

  Thus, the air conditioning system can be stably operated by performing the flow rate reduction process and the flow rate increase process only when the difference between the maximum value and the minimum value of the index is greater than or equal to a predetermined index threshold value. For example, when there is almost no difference between the maximum value and the minimum value of the index, the heat source and chilled water pump unit subject to flow rate reduction processing, and the heat source and chilled water pump unit subject to flow rate increase processing are replaced in a short period of time. There is a possibility that driving becomes unstable. Therefore, the operation of the heat source and the chilled water pump unit can be stabilized by performing the flow rate reduction process and the flow rate increase process only when the difference between the maximum value and the minimum value of the index is greater than or equal to a predetermined index threshold value.

  In the above invention, the measurement unit is a temperature sensor that measures the temperature of the outdoor air that is ventilated to the condenser, and the integrated control unit uses the temperature of the outdoor air as an index to measure the outdoor air temperature. Preferably, the flow rate reduction process is performed on the heat source having the highest temperature, and the flow rate increase process is performed on the heat source having the lowest outdoor air temperature.

  Thus, by using the temperature of the outdoor air measured by the temperature sensor as an index, the efficiency of the entire air conditioning system can be easily improved. When the efficiency of the heat source is used as an index, the power source efficiency is measured by measuring the power consumption and cooling capacity of the heat source, and the compressor operating state, cold water inflow temperature, outflow temperature, and cold water flow rate are calculated. Measuring the efficiency of the heat source. When the temperature of the outdoor air is used as an index, the number of measurement items is small and the amount of calculation when performing the flow rate reduction process or the flow rate increase process can be reduced compared to the case where the efficiency of the heat source is used as an index.

  In the above invention, the measurement unit is an efficiency measurement unit that measures the efficiency of the heat source, and the integrated control unit uses the efficiency output from the efficiency measurement unit as the index, and the flow rate reduction process and the flow rate increase process. It is preferable to carry out.

  Thus, by providing the efficiency measuring unit and measuring the efficiency of the heat source, it becomes easy to improve the efficiency of the entire air conditioning system. When the temperature of the outdoor air ventilated in the condenser is used as an index, the efficiency with respect to the heat source is estimated from the temperature of the outdoor air. When the efficiency of the heat source is indexed, it is easier to ensure the accuracy of the selection of the heat source that is the target of the flow rate reduction process and the selection of the heat source that is the target of the flow rate increase process, compared to the case where the temperature of the outdoor air is used as an index. Become.

  Examples of the efficiency measurement unit that measures the efficiency of the heat source include a measurement unit that measures the power consumption of the heat source and a measurement unit that measures the cooling capacity. Furthermore, a measurement unit that measures the operating state of the compressor, a measurement unit that measures the inflow temperature of cold water, a measurement unit that measures the outflow temperature, and a measurement unit that measures the flow rate of cold water can also be mentioned.

  According to the air conditioning system of the present invention, by reducing the heat load on the heat source with the lowest efficiency and increasing the heat load on the heat source with the highest efficiency, variation in efficiency among the plurality of heat sources can be suppressed, and the entire system can be reduced. There is an effect that the efficiency can be improved.

It is a mimetic diagram explaining the schematic structure of the air-conditioning system concerning one embodiment of the present invention. It is a block diagram explaining the structure relevant to the chiller control part of FIG. It is a block diagram explaining the structure relevant to the integrated control part of FIG. It is a flowchart explaining the noise reduction control in the fan part of FIG. It is a schematic diagram explaining another Example in the air conditioning system of FIG.

  An air conditioning system 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. The air conditioning system 1 of the present embodiment is used for air conditioning of a data center, and processes a large amount of heat generated from a server or computer (hereinafter referred to as “server etc.”) installed on the floor of the data center. To do.

  In the air conditioning system 1, as shown in FIG. 1, one or more air handling units (air conditioners) 10 (hereinafter referred to as “AHU10”) installed on the floor and installed outside the data center. The three air-cooled chillers (heat sources) 20, the chilled water pipe 31 that connects the AHU 10 and the air-cooled chiller 20 so that the chilled water can circulate, and the integrated control unit 40 that integrates and controls the three air-cooled chillers 20. It is configured.

  In FIG. 1, only one AHU 10 is shown for easy understanding. Furthermore, in the present embodiment, description will be made by applying to an example of the air conditioning system 1 provided with a group of three air-cooled chillers 20, but the number of air-cooled chillers 20 may be two or more than three. There may be many and it does not specifically limit.

  The AHU 10 uses the cold water supplied from the air-cooled chiller 20 to cool the indoor air on the floor whose temperature has been increased by heat from a server or the like. The AHU 10 is mainly provided with a coil 11 that is a heat exchanger and an AHU fan 12. In the coil 11, cold water having a predetermined temperature (for example, 7 ° C.) supplied from the air-cooled chiller 20 through the cold water pipe 31 is allowed to flow inside, and the room air blown by the AHU fan 12 flows outside. It is configured. Further, the coil 11 is formed in a shape in which the surface area in contact with the cold water and the surface area in contact with the room air increase in order to increase the heat exchange efficiency.

  The air-cooled chiller 20 cools the cold water whose temperature has increased (for example, 12 ° C.) by absorbing the heat of the room air in the AHU 10, and sends it to the AHU 10 again as cold water having a predetermined temperature. As shown in FIGS. 1 and 3, the air-cooled chiller 20 includes a compressor 21, a condenser 22, an expansion valve 23, an evaporator 24, a fan unit 25, a cold water pump unit 26, and an input wattmeter. An (efficiency measurement unit) 27, a cooling capacity meter (efficiency measurement unit) 28, and a chiller control unit (individual control unit) 29 are mainly provided.

  The compressor 21 constitutes a refrigeration circuit together with the condenser 22, the expansion valve 23, and the evaporator 24. The compressor 21 sucks and compresses the gaseous refrigerant from the evaporator 24 and discharges the high-temperature and high-pressure gaseous refrigerant to the condenser 22. In the present embodiment, description will be made by applying to an example in which a compression motor that can control the rotation speed by the chiller control unit 29 is used as a power source of the compressor 21. As the format of the compressor 21, a known format such as a scroll format or a rotary format can be used.

  The condenser 22 takes heat from the gaseous refrigerant discharged from the compressor 21 and condenses it into a liquid refrigerant. In other words, the condenser 22 is a heat exchanger that exchanges heat between the outdoor air ventilated by the fan unit 25 and the gaseous refrigerant. The high-pressure liquid refrigerant condensed in the condenser 22 flows out toward the expansion valve 23.

  The expansion valve 23 adiabatically expands the high-pressure liquid refrigerant flowing from the condenser 22 to make a low-pressure refrigerant. The refrigerant that has passed through the expansion valve 23 is in a gas-liquid two-phase state in which liquid refrigerant and gas refrigerant are mixed. In the present embodiment, description will be made by applying to an example in which the opening degree of the valve is the expansion valve 23 that can be controlled by the chiller control unit 29.

  The evaporator 24 absorbs the heat of cold water in the refrigerant (mainly liquid refrigerant) that has passed through the expansion valve 23 and evaporates it into a gas refrigerant. In other words, the evaporator 24 is a heat exchanger that exchanges heat between the cold water returned from the AHU 10 and the liquid refrigerant. The refrigerant turned into gas in the evaporator 24 is sucked into the compressor 21 and the above cycle is repeated again. In addition, as a form of the condenser 22 or the evaporator 24, a well-known form such as a coil type or a fin tube type can be used, and the form is not particularly limited.

  The fan unit 25 is disposed in the vicinity of the condenser 22 and guides outdoor air to the inside of the air-cooled chiller 20 to circulate around the condenser 22. The rotation frequency of the fan unit 25 is controlled by the chiller control unit 29.

  As shown in FIG. 1, the chilled water pump unit 26 sends chilled water from the air-cooled chiller 20 toward the AHU 10, and circulates chilled water in the chilled water pipe 31. The chilled water pump unit 26 is provided with a pump electric motor (not shown) for driving the pump, and the rotation speed of the pump motor is controlled by the chiller control unit 29. In the present embodiment, description will be made by applying to an example in which the chilled water pump unit 26 is provided in the air-cooled chiller 20, but the chilled water pump unit 26 may be provided separately from the air-cooled chiller 20, and is not particularly limited. .

  The input wattmeter 27 measures the power supplied to the air-cooled chiller 20. More specifically, the power supplied to the compressor 21, the fan unit 25, and the cold water pump unit 26 of the air-cooled chiller 20 is measured. The power value measured by the input wattmeter 27 is output to the integrated control unit 40.

  The cooling capacity meter 28 measures the cooling capacity in the air cooling chiller 20. In other words, the ability to cool the cold water whose temperature is increased (for example, 12 ° C.) by absorbing the heat of room air in the AHU 10 to a predetermined temperature (for example, 7 ° C.) is measured. The value of the cooling capacity measured by the cooling capacity meter 28 is output to the integrated control unit 40.

  The chiller control unit 29 is a control unit provided in each of the plurality of air-cooled chillers 20, and is a microcomputer having a CPU (Central Processing Unit), a ROM, a RAM, an input / output interface, and the like. As shown in FIG. 2, the chiller control unit 29 receives the temperature of the chilled water output from the chilled water temperature sensor 32 that measures the temperature of the chilled water sent from the air-cooled chiller 20. The chiller control unit 29 controls the rotational speed of the compression motor that drives the compressor 21 so that the temperature of the cold water delivered from the air-cooled chiller 20 is maintained at a predetermined temperature (for example, 7 ° C.). Is to do. In addition, as a method of capability control, a known control method can be used, and a specific control method is not limited.

  The integrated control unit 40 is provided in the air conditioning system 1 and controls the plurality of air cooling chillers 20 in an integrated manner, and is a microcomputer having a CPU (Central Processing Unit), ROM, RAM, input / output interface, and the like. The control program stored in the ROM or the like causes the CPU to function as the determination unit 41, and causes the ROM or the like to function as the storage unit 42.

  As shown in FIG. 3, the integrated control unit 40 includes a chilled water pump unit 26, an input power meter 27, and a cooling capacity meter 28 in the three air-cooled chillers 20, respectively, a chilled water flow rate signal, an input power value signal, and a cooling capacity. It is connected so that a value signal can be input. Moreover, it connects so that a control signal can be output from the integrated control part 40 to the compressor 21 and the cold water pump part 26. FIG. Specific control contents in the integrated control unit 40 will be described later.

  Next, the control of the integrated control unit 40 for improving the overall efficiency in the air conditioning system 1 which is a feature of the present embodiment will be described with reference to the flowchart of FIG. Note that the control for improving efficiency described here is control performed independently and in parallel with the above-described capability control.

  When the operation of the air conditioning system 1 is started, the integrated control unit 40 is a process of acquiring an appropriate amount (required flow rate) that is a flow rate of cold water requested from the AHU 10 and a flow rate of cold water supplied from the air cooling chiller 20. A process for obtaining the supply flow rate is executed. And the determination part 41 of the integrated control part 40 performs the determination process whether a supply flow volume is less than an appropriate quantity (S11: comparison process).

  When it is determined that the supply flow rate is less than the appropriate amount (in the case of YES), the determination unit 41 further performs a process of determining whether there is an air-cooled chiller 20 that is thermo-off (S12). The air-cooled chiller 20 that is thermo-off here is a chiller in which the compressor 21 and the cold water pump unit 26 are stopped. For example, the determination unit 41 can perform the determination of S12 by determining whether or not the value of the input power input from the input power meter 27 is zero.

  When it is determined that there is an air-cooled chiller 20 that is thermo-off (in the case of YES), the integrated control unit 40 performs a process of outputting a control signal that activates the air-cooled chiller 20 and the chilled water pump unit 26 that are thermo-off. Execute (S13: start-up process). At this time, the air-cooled chiller 20 and the cold water pump unit 26 are activated with, for example, the lowest efficiency and the supply flow rate. Specifically, the compressor 21 and the cold water pump unit 26 are driven at a minimum frequency. Thereafter, the integrated control unit 40 returns to S11 again and executes the above-described processing.

  In the determination process of S12, when it is determined that there is no thermo-cooled air-cooled chiller 20 (in the case of NO), the integrated control unit 40 has the highest efficiency (also expressed as “COP”). On the other hand, the process which outputs the control signal which raises the drive frequency of the cold water pump part 26 two steps is performed (S14: flow rate increase process). In other words, a process of increasing the flow rate of the cold water sent from the cold water pump unit 26 belonging to the air cooling chiller 20 having the highest efficiency is executed.

  Furthermore, the process which outputs the control signal which lowers | hangs the drive frequency of the chilled water pump part 26 1 step with respect to the air cooling chiller 20 with the lowest efficiency is performed (S15: flow volume reduction process). In other words, a process of reducing the flow rate of the cold water sent from the cold water pump unit 26 belonging to the air cooling chiller 20 having the lowest efficiency is executed. At this time, the flow rate of the cold water to be reduced is smaller than the flow rate of the cold water to be increased. Thereafter, the integrated control unit 40 returns to S11 again and executes the above-described processing.

  In the determination process of S11, when it is determined that the supply flow rate is equal to or greater than the appropriate amount (in the case of NO), the determination unit 41 further executes a determination process as to whether or not the supply flow rate is equal to the appropriate amount ( S16: Comparison process). When it is determined that the supply flow rate is not equal to the appropriate amount (that is, the supply flow rate is larger than the appropriate amount) (in the case of NO), the integrated control unit 40 performs the highest efficiency on the air-cooled chiller 20. The process which outputs the control signal which raises the drive frequency of the cold water pump part 26 by one step is performed (S17: flow rate increase process).

  Furthermore, the process which outputs the control signal which lowers | hangs the drive frequency of the chilled water pump part 26 two steps with respect to the air cooling chiller 20 with the lowest efficiency is performed (S18: flow rate reduction process). At this time, the flow rate of the cold water to be increased is smaller than the flow rate of the cold water to be decreased. Thereafter, the integrated control unit 40 returns to S11 again and executes the above-described processing.

  When it is determined in the determination process of S16 that the supply flow rate is equal to the appropriate amount (in the case of YES), the determination unit 41 determines whether the difference between the highest efficiency and the lowest efficiency is greater than or equal to a threshold value (index threshold value). A determination process of whether or not is executed (S19). Here, the threshold value is stored in advance in the storage unit 42, and 0.5 may be exemplified as the threshold value. When it is determined that the difference between the highest efficiency and the lowest efficiency is less than the threshold (in the case of NO), the integrated control unit 40 returns to S11 again and executes the above-described processing.

  In the determination process of S19, when it is determined that the difference between the highest efficiency and the lowest efficiency is equal to or greater than the threshold value (in the case of YES), the integrated control unit 40, for the air-cooled chiller 20 with the highest efficiency, The process which outputs the control signal which raises the drive frequency of the cold water pump part 26 by one step is performed (S20: flow rate increase process).

  Furthermore, the process which outputs the control signal which lowers | hangs the drive frequency of the chilled water pump part 26 one step is performed with respect to the air cooling chiller 20 with the lowest efficiency (S21: flow rate reduction process). At this time, the flow rate of the cold water to be increased is the same as the flow rate of the cold water to be decreased. Thereafter, the integrated control unit 40 returns to S11 again and executes the above-described processing.

  According to the air conditioning system 1 having the above configuration, the thermal load on the air-cooling chiller 20 having the lowest efficiency is reduced, and the thermal load on the air-cooling chiller 20 having the highest efficiency is increased. Therefore, the efficiency of the air conditioning system 1 as a whole can be improved. That is, by reducing the flow rate of the cold water sent out from the cold water pump unit 26 provided in the air cooling chiller 20 having the lowest efficiency, the amount of heat taken from the cold water in the evaporator 24 can be reduced, and the heat load on the air cooling chiller 20 can be reduced. Further reduction in efficiency in the air-cooled chiller 20 is suppressed.

  This decrease in the chilled water flow rate corresponds to an increase in the flow rate of chilled water delivered from the chilled water pump unit 26 provided in the air cooling chiller 20 having the highest efficiency, and the chilled water flow required for the AHU 10 is supplied as a whole. Is done. The flow rate increasing process and the flow rate are reduced by reducing the flow rate of the chilled water sent from the chilled water pump unit 26 of the air cooling chiller 20 having the lowest efficiency after increasing the chilled water flow rate sent from the chilled water pump unit 26 of the air cooling chiller 20 having the highest efficiency. Insufficient chilled water flow rate can be suppressed during the transitional period of reduction treatment.

  Further, by increasing the flow rate of the chilled water in the air-cooled chiller 20 having the highest efficiency, the amount of heat taken from the chilled water in the evaporator 24 increases and the heat load on the air-cooled chiller 20 increases. Therefore, the efficiency in the air-cooled chiller 20 is slightly reduced, and variation in efficiency among the plurality of air-cooled chillers 20 can be suppressed.

  In the determination process of S11 and S16, a comparison process for comparing the supply flow rate and the appropriate amount is performed. Based on the comparison result, the flow rate increase amount of the chilled water in the flow rate increase process of S14, S17 and S20, and S15, S18 and S21 By adjusting the flow rate reduction amount of the cold water in the flow rate reduction process, the supply flow rate and the appropriate amount can be made equal. In particular, in the flow rate reduction process of S15, S18, and S21 performed after the flow rate increase process of S14, S17, and S20, the supply flow rate can be easily made equal to the required flow rate by adjusting the flow rate decrease amount of the cold water.

  Before performing the flow rate increase process of S14 and the S15 flow rate decrease process, the air-cooled chiller 20 and the cold water pump unit 26 that are stopped are activated, and all the air-cooled chiller 20 and the cold water pump unit 26 are operated, thereby air conditioning. The efficiency of the system 1 as a whole can be improved. That is, by operating all the air cooling chillers 20 and the chilled water pump unit 26, the areas of the evaporator 24 and the condenser 22 that can be used in the air conditioning system 1 can be maximized. The efficiency of the air conditioning system 1 as a whole can be improved as compared with the case where the area is small.

  Only when the difference between the maximum value and the minimum value of the efficiency is greater than or equal to the threshold value, the air conditioning system 1 can be stably operated by performing the flow rate reduction process of S21 and the S20 flow rate increase process. For example, when there is almost no difference between the maximum value and the minimum value of efficiency, the air-cooled chiller 20 and the chilled water pump unit 26 that are subject to the flow rate reduction process of S21, and the air-cooled chiller 20 that is the subject of the S20 flow rate increase process and There is a possibility that the chilled water pump unit 26 is replaced in a short period of time, and the operation becomes unstable. Therefore, only when the difference between the maximum value and the minimum value of the efficiency is equal to or greater than the threshold value, the operation of the air cooling chiller 20 and the chilled water pump unit 26 is stabilized by performing the flow rate reduction process of S21 and the S20 flow rate increase process. Can do.

  By providing the input power meter 27 and the cooling capacity meter 28 and measuring the efficiency of the air-cooling chiller 20, it becomes easy to improve the efficiency of the air conditioning system 1 as a whole. When control is performed based on the temperature of the outdoor air that is ventilated through the condenser 22, the heat load on the air-cooled chiller 20 is estimated from the temperature of the outdoor air. When the control is performed based on the efficiency of the heat source, the selection of the air-cooled chiller 20 to be subjected to the flow rate reduction processing of S15, S18, and S21, or S14, S17, compared to the case of performing the control based on the temperature of the outdoor air. And it becomes easy to ensure the accuracy of selection of the air-cooled chiller 20 to be the target of the flow rate increasing process of S20.

  Note that, as in the above-described embodiment, the input power meter 27 and the cooling capacity meter 28 may be provided to directly determine the efficiency of the air cooling chiller 20, or the driving frequency of the compressor 21 and the cold water flowing into the air cooling chiller 20 may be obtained. The efficiency of the air-cooled chiller 20 may be indirectly provided by providing a measuring unit for measuring the temperature, the temperature of the cold water flowing out from the air-cooled chiller 20, and the flow rate of the cold water, and the method for obtaining the efficiency is particularly limited. is not.

  Further, as in the above-described embodiment, in the process of S13, the air-cooled chiller 20 and the cold water pump unit 26 that are thermo-off may be activated unconditionally, or in the air-cooled chiller 20 and the cold water pump unit 26 that are thermo-off. When the total operation time is longer than the total operation time in the other air-cooled chiller 20 and the chilled water pump unit 26, the air-cooled chiller 20 and the chilled water pump unit 26 that are thermo-off need not be activated.

  When the total operation time of the air-cooled chiller 20 and the chilled water pump unit 26 stopped in this way is long, the flow rate increasing process of S14, S17, and S20 only for the other air-cooled chiller 20 and the chilled water pump unit 26, In addition, by performing the flow rate reduction processing of S15, S18, and S21, it becomes easy to equalize the operation time of the air cooling chiller 20 and the cold water pump unit 26, particularly the operation time of the compressor 21 of the air cooling chiller 20.

  Further, as in the above-described embodiment, in the process of S13, the total operation time in the air-cooled chiller 20 and the chilled water pump unit 26 that is thermo-off is greater than the total operation time in the other air-cooled chiller 20 and the chilled water pump unit 26. When the outdoor air temperature is longer than the activation threshold, the air-cooled chiller 20 and the cold water pump unit 26 that are thermo-off need not be activated.

  That is, even if the total operation time of the stopped air-cooling chiller 20 and the chilled water pump unit 26 is long, if the outdoor air temperature is higher than the activation threshold, the stopped air-cooling chiller 20 and the chilled water pump unit 26 are stopped. Start process to start In other words, when the temperature of the outdoor air is high and it is difficult to improve the efficiency of the air-cooled chiller 20, a process of giving priority to the improvement of the efficiency over the leveling of the operation time is performed.

  As described above, only when the outdoor air temperature further satisfies the condition of the activation threshold or less, the flow rate increasing process of S14, S17, and S20 for only the other air-cooled chiller 20 and the chilled water pump unit 26, and S15, By performing the flow reduction processing of S18 and S21, the operation time of the air cooling chiller 20 and the chilled water pump unit 26, particularly the operation time of the compressor 21 of the air cooling chiller 20 is leveled, and the efficiency of the air conditioning system 1 as a whole is improved. Can be balanced.

  In the flow rate increasing process of S14, S17, and S20 in the above-described embodiment, only the example of increasing the driving frequency of the chilled water pump unit 26 belonging to the air cooling chiller 20 having the highest efficiency has been described. However, the air cooling chiller 20 having the highest efficiency. When the driving frequency in the chilled water pump unit 26 has reached the upper limit of a predetermined capacity value, control is performed to increase the driving frequency for the chilled water pump unit 26 belonging to the air cooling chiller 20 having the next highest efficiency. You may go.

  When the flow rate of the chilled water pumped out cannot be increased any more for the chilled water pump unit 26 provided in the air cooling chiller 20 having the highest efficiency in this way, the chilled water pump unit provided in the air cooling chiller 20 having the next highest efficiency. By performing control to increase the flow rate of chilled water sent out to 26, the air conditioning system 1 as a whole can easily suppress shortage of the chilled water flow rate.

  Further, as in the above-described embodiment, the determination process of S11 and S16 is performed based on the supply flow rate that is the total flow rate of the cold water sent out from the cold water pump unit 26, the flow rate increase process of S14, S17, and S20, and S15. The flow rate reduction process of S18 and S21 may be performed, or the determination process of S11 and S16 may be performed based on the pressure of the cold water sent out from the cold water pump unit 26. At this time, in the determination processing of S11 and S16, a comparison is made between the supply pressure, which is the pressure of the cold water delivered from the cold water pump unit 26, and the appropriate pressure.

  Moreover, like the above-mentioned embodiment, based on the efficiency of the air cooling chiller 20, you may perform the flow increase process of S14, S17, and S20, the flow decrease process of S15, S18, and S21, and the determination process of S19. Based on the temperature of the outdoor air measured by the temperature sensor instead of the efficiency of the air cooling chiller 20, the flow increase process of S14, S17 and S20, the flow decrease process of S15, S18 and S21, and the determination process of S19 are performed. Also good.

  By providing the temperature sensor and measuring the temperature of the outdoor air ventilated through the condenser 22, the efficiency of the air conditioning system 1 as a whole can be easily improved. When the control is performed based on the efficiency of the heat source, the efficiency of the air cooling chiller 20 is obtained by measuring two of the power consumption and the cooling capacity of the air cooling chiller 20. On the other hand, when the control is performed based on the temperature of the outdoor air, the number of measurement items is less than in the case where the control is performed based on the efficiency of the air-cooled chiller 20, and the flow rate increasing process of S14, S17 and S20, or S15 , S18 and S21 can be reduced, and the amount of calculation when performing the determination process of S19 can be reduced.

  Further, as in the above-described embodiment, the air cooling chiller 20 may not be provided with a function of watering the condenser 22, and a watering device 51 for watering the condenser 22 as shown in FIG. It may be provided. When water is sprinkled on the condenser 22, the water adhering to the outer surface of the condenser 22 is deprived of heat of the refrigerant when the water evaporates, so that the condensation capacity of the condenser 22 is improved. In this case, the flow rate increasing process of S14, S17, and S20 and the flow rate decreasing process of S15, S18, and S21 are not performed on the air-cooled chiller 20 in which water is sprayed from the watering device 51.

  Except for the air-cooled chiller 20 and the chilled water pump unit 26 that perform the watering treatment in this way, the flow rate increasing process of S14, S17, and S20, and the flow rate decreasing process of S15, S18, and S21 are performed, so that the air conditioning system 1 The increase in running cost can be suppressed.

  Generally, when watering treatment is performed, the cost of water to be sprinkled (for example, a water charge) is generated. Therefore, in order to suppress an increase in running cost, it is preferable to shorten the period of watering treatment.

  However, if the flow rate increasing process of S14, S17 and S20 and the flow rate decreasing process of S15, S18 and S21 are also performed on the air cooling chiller 20 and the cold water pump unit 26 which are performing the watering process, the other air cooling chillers 20 will be described. Compared with, the load tends to concentrate, so the watering treatment cannot be terminated, and the period of the watering treatment tends to be long. Therefore, the running of the air conditioning system 1 is performed by removing the air cooling chiller 20 and the cold water pump unit 26 that perform the watering treatment from the targets of the flow rate increasing process of S14, S17, and S20 and the flow rate decreasing process of S15, S18, and S21. Cost increase can be suppressed.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the present invention is not limited to those applied to the above-described embodiments, and may be applied to embodiments obtained by appropriately combining these embodiments, and is not particularly limited.

  DESCRIPTION OF SYMBOLS 1 ... Air conditioning system, 10 ... Air handling unit (air conditioner), 20 ... Air cooling chiller (heat source), 21 ... Compressor, 22 ... Condenser, 23 ... Expansion valve, 24 ... Evaporator, 25 ... Fan part, 26 ... Chilled water pump unit, 27 ... charged wattmeter (efficiency measuring unit), 28 ... cooling capacity meter (efficiency measuring unit), 29 ... chiller control unit (individual control unit), 40 ... integrated control unit, 51 ... sprinkler, S11, S16: Comparison process, S13: Start-up process, S14, S17, S20 ... Flow rate increase process, S15, S18, S21 ... Flow rate decrease process

Claims (10)

A plurality of heat sources that are installed outdoors and supply cold water of a predetermined temperature, an air conditioner that cools indoor air using the cold water that is installed and supplied indoors, and cold water that is supplied from each of the plurality of heat sources An integrated controller for controlling the amount and activation and deactivation of the heat source, and
The heat source includes a compressor that compresses the gas refrigerant to a high pressure, a condenser that condenses the gas refrigerant into a liquid refrigerant by releasing heat of the high-pressure gas refrigerant to outdoor air, and a high-pressure An expansion valve that expands the liquid refrigerant to make the pressure low, an evaporator that removes heat from the cold water and evaporates the low-pressure liquid refrigerant, a cold water pump unit that supplies the cold water to the air conditioner, and an air conditioner An air conditioning system comprising: an individual control unit that controls at least the compressor so that the cold water to be supplied maintains the predetermined temperature,
Each of the plurality of heat sources is provided with a measurement unit that measures an index related to efficiency in the heat source,
The integrated control unit is based on the index output from the measurement unit,
A flow rate increasing process for increasing the flow rate of the cold water sent from the cold water pump unit provided in the heat source having the highest efficiency,
A flow rate reduction process for reducing the flow rate of the cold water sent from the cold water pump unit provided in the heat source having the lowest efficiency;
An air conditioning system characterized by performing. The integrated control unit receives a required flow rate that is the flow rate of the cold water required by the air conditioner,
The integrated control unit performs a comparison process of comparing the supply flow rate that is the sum of the flow rates of the cold water supplied from a plurality of heat sources with the required flow rate,
When the required flow rate is larger than the supply flow rate, the flow rate of the cold water increased in the flow rate increasing process is larger than the flow rate of the cold water reduced in the flow rate decreasing process,
When the required flow rate is smaller than the supply flow rate, the flow rate of the cold water that is increased in the flow rate increasing process is smaller than the flow rate of the cold water that is decreased in the flow rate decreasing process,
The flow rate of the cold water increased in the flow rate increasing process is made equal to the flow rate of the cold water decreased in the flow rate decreasing process when the required flow rate is equal to the supply flow rate. Air conditioning system. When the required flow rate is larger than the supply flow rate in the comparison process, when the heat source and the cold water pump unit that are stopped are present,
The integrated control unit performs a starting process for operating all the heat sources and the cold water pump unit,
3. The air conditioning system according to claim 2, wherein the flow rate increasing process and the flow rate decreasing process are performed thereafter.   The integrated control unit increases the flow rate without performing the start-up process when the total operation time of the stopped heat source and the cold water pump unit is longer than that of the other heat sources and the cold water pump unit. The air conditioning system according to claim 3, wherein the processing and the flow rate reduction processing are performed.   The integrated control unit is configured such that the total operation time of the stopped heat source and the cold water pump unit is longer than the other heat sources and the cold water pump unit, and the temperature of the outdoor air is equal to or lower than a startup threshold. 4. The air conditioning system according to claim 3, wherein the flow rate increasing process and the flow rate decreasing process are performed without performing the startup process. In the flow rate increasing process, when the flow rate of the cold water sent from the cold water pump unit provided in the heat source having the highest efficiency has reached a predetermined upper limit, the heat source having the next highest efficiency air conditioning system as claimed in claim 1 in any one of 5, characterized in that to increase the cold water flow issued Ri sent from the chilled water pump unit provided. The heat source is further provided with a watering device for watering the condenser,
The said integrated control part does not perform the said flow volume increase process and the said flow volume reduction process with respect to the said heat source and the said cold water pump part in which watering is performed from the said watering apparatus. The air conditioning system according to any one of the above.   The integrated control unit performs the flow rate reduction process and the flow rate increase process when the difference between the maximum index and the minimum index among the indexes output from the plurality of measurement units is equal to or greater than a predetermined index threshold. It performs, The air conditioning system of any one of Claim 1 to 7 characterized by the above-mentioned. The measurement unit is a temperature sensor that measures the temperature of the outdoor air that is ventilated to the condenser.
The integrated control unit performs the flow rate reduction process on the heat source having the highest outdoor air temperature, with the temperature of the outdoor air as the index, and the heat source having the lowest outdoor air temperature. The air conditioning system according to any one of claims 1 to 8, wherein the flow rate increasing process is performed. The measurement unit is an efficiency measurement unit that measures the efficiency of the heat source,
The air conditioning according to any one of claims 1 to 8, wherein the integrated control unit performs the flow rate reduction process and the flow rate increase process using the efficiency output from the efficiency measurement unit as the index. system.

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