JP5363212B2 - Air conditioning system - Google Patents

Abstract

An air-conditioning method comprises the steps of performing a refrigerator operation using a refrigerator to which cooling water cooled in a plurality of cooling towers is supplied as a cold heat source, and performing a free cooling operation using at least some of the plurality of cooling towers as a cold heat source, wherein at a time of the free cooling operation, the number of the cooling towers which are operated is controlled.

Description

  The present invention relates to an air conditioning method and an air conditioning system, and more particularly to an air conditioning method and an air conditioning system such as a clean room and a building air conditioner.

  Cooling operations are performed throughout the year in clean rooms and building facilities. For this reason, energy saving is an important issue in the air conditioning system of these facilities, and in recent years, free cooling has been implemented (see Patent Document 1).

  Free cooling is a system that performs a freezer operation using a refrigerator as a cold source in the summer and a free cooling operation using a cooling tower as a cold source in the winter without using the refrigerator. According to this system, since the cooling can be performed without operating the refrigerator in winter, a great energy saving effect can be expected.

  By the way, in such an air conditioning system, there are a case where a single cooling tower is shared in both the refrigerator operation and the free cooling operation, and a case where a dedicated cooling tower is used for each.

JP 2004-132651 A

  However, in either case, energy consumption in the cooling tower is wasted. For example, when a single cooling tower is shared, the amount of cooling water required (that is, the amount of cooling heat) differs between the refrigerator operation and free cooling operation, so the cooling tower must be operated in accordance with either operation. In the other operation, energy is wasted.

  In addition, when a dedicated cooling tower is used for each of the refrigerator operation and the free cooling operation, there arises a problem that energy efficiency is reduced when the operation is resumed.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an air conditioning method and an air conditioning system capable of optimizing the energy consumption of a cooling tower.

In order to achieve the above object, the present invention operates a refrigerator that uses a refrigerator supplied with cooling water cooled by a plurality of cooling towers as a cooling source, and uses at least a part of the plurality of cooling towers as a cooling source. An air conditioning method for performing free cooling operation, wherein during the free cooling operation, the number of operating cooling towers is controlled, and at least a part of the plurality of cooling towers is used in combination with the refrigerator as a cooling heat source. And controlling the number of operating cooling towers serving as the cooling heat source during the intermediate operation, switching the operation according to the outside air temperature and the air conditioning load condition, providing a plurality of the refrigerators, The number of operating cooling towers is commonly controlled for each refrigerator .

  According to the present invention, by controlling the number of operating cooling towers during free cooling operation, an optimal amount of cold heat can be generated in each operation mode, and the overall energy consumption can be reduced. .

  The combined use of a cooling tower and a refrigerator means that the cooling tower and the refrigerator are connected in series. For example, the cooling water cooled by the cooling tower is further cooled by the refrigerator, and the air conditioning load section When supplying to.

  According to the present invention, since the number of operating cooling towers is controlled even during an intermediate operation, an appropriate amount of cold can be generated. Thereby, the energy consumption in the whole can be reduced.

  According to the present invention, the amount of cold heat (cooling water temperature and flow rate) at which energy consumption is minimized can be determined by simulation or the like depending on the outside air temperature and the air conditioning load condition. Therefore, by controlling the number of operating cooling towers according to the result, an air-conditioning operation that minimizes energy consumption can be performed.

  According to the present invention, since the number of operating cooling towers is controlled for each refrigerator, for example, even when the amount of cooling heat required for each refrigerator is different, the minimum amount of cooling heat is supplied to each refrigerator. And overall energy consumption can be reduced.

The refrigerator is a turbo refrigerator, it is preferable to perform inverter control. According to this embodiment , it is possible to reduce the energy consumption of the refrigerator.

It is preferable to control the flow rate of the cooling water by controlling the number of rotations of a pump that circulates the cooling water cooled by the plurality of cooling towers or the refrigerator. According to this form , the energy consumption concerning the circulation of cooling water can be reduced.

In order to achieve the above object, the present invention circulates a plurality of cooling towers for cooling cooling water, a plurality of refrigerators having a condenser and an evaporator, and cooling water cooled by the cooling tower to the condenser. together with the refrigerator operating circulation line for circulating the cooling water cooled by the evaporator to the air conditioning load unit, and a free cooling operation for circulation line for circulating the cooling water cooled in the cooling tower in the air-conditioning load unit, Line switching means for switching between the circulation line for freezer operation and the circulation line for free cooling operation, and adjusting the number of cooling towers connected to the circulation line for free cooling operation, and the plurality of cooling towers The intermediate operation circulation line connected in series to the evaporator of the refrigerator and the line switching means perform line switching including the intermediate operation circulation line. The change of the number of cooling tower is connected to an intermediate operation for the circulation line, and change the number of the cooling tower which is connected to the refrigerator, for controlling said line switching means in accordance with the outside air temperature and the air conditioning load conditions In addition, an air conditioning system comprising: a control device that individually controls operation and stop of the plurality of cooling towers.

  According to the present invention, the number of operating cooling towers during free cooling operation can be controlled. Therefore, it is possible to generate an amount of cold energy suitable for each operation mode, and to reduce the energy consumption in the entire system.

  According to the present invention, by connecting the cooling tower and the evaporator of the refrigerator in series, an intermediate operation using both the cooling tower and the refrigerator as a cold heat source can be performed. Furthermore, according to the present invention, the number of operating cooling towers during intermediate operation can be controlled. Therefore, it can be adjusted to the amount of cold heat (cooling water temperature and flow rate) suitable for intermediate operation, and the energy consumption of the entire system can be reduced. The intermediate operation circulation line may also be used as a free cooling circulation line. In this case, the intermediate operation circulation line can be used as a free cooling operation circulation line by stopping the refrigerator.

  According to the present invention, the number of operating cooling towers can be controlled for each of a plurality of refrigerators. Therefore, even if the required amount of cooling energy differs among the plurality of refrigerators, it is possible to generate a cooling energy amount suitable for each. Thereby, the energy consumption in the whole system can be reduced.

  According to the present invention, by controlling the number of operating cooling towers, an optimal amount of cold heat can be generated in each operation mode, and energy consumption in the entire system can be reduced.

The system diagram which shows typically the structure of the air conditioning system of 1st Embodiment. The figure which shows the pipe line structure for every operation mode typically. The system diagram which shows the air-conditioning system of piping structure different from FIG. The system diagram which shows the modification of the air conditioning system of FIG. The system diagram which shows typically the structure of the air conditioning system of 2nd Embodiment. The figure which shows the pipe line structure for every operation mode typically. The system diagram which shows typically the structure of the air conditioning system of 3rd Embodiment. The figure which shows the pipe line structure for every operation mode typically. The figure which shows the pipe line structure for every operation mode typically. The system diagram which shows the modification of the air conditioning system of FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an air conditioning method and an air conditioning system according to the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a system diagram schematically showing the configuration of the air conditioning system of the first embodiment. The air conditioning system 10 shown in the figure is a system that performs air conditioning of the clean room facility 12.

  In the clean room facility 12, a fan filter unit 16 (hereinafter, “FFU”) is provided on the ceiling surface of the clean room 14, and the air in the ceiling back space 18 is purified by this FFU 16 and downflowed to the clean room 14. The floor surface of the clean room 14 is a grating floor, and the air in the clean room 14 is sucked into the underfloor space 20 and further returned to the ceiling back space 18 via the return chamber 22. Thereby, the air in the ceiling space 18 is sent again to the clean room 14 by the FFU 16, and the clean room 14 is maintained at a high cleanliness.

  The return chamber 22 is provided with a sensible heat treatment coil 24 </ b> Y so that the air flowing through the return chamber 22 can be cooled to process the sensible heat. The clean chamber 14 is provided with a device 26 such as a semiconductor manufacturing device. The device 26 is provided with a coil 28 so that the refrigerant circulates between the coil 28 and the heat exchanger 24X for loading the device. It has become. Further, the clean room facility 12 is provided with an external air conditioner 30. The external air conditioner 30 includes an external air conditioner coil 24 </ b> Z, a humidifier 32, a heater 34, a fan 36, a filter (not shown), and the like, and external air is sucked by driving the fan 36. Then, dust is removed by a filter (not shown), cooled by the coil 24Z for the external air conditioner, humidified by the humidifier 32, heated as necessary by the heater 34, and then supplied into the facility.

  The air conditioning system 10 of the present embodiment is a system that supplies cooling heat to the apparatus load heat exchanger 24X, the sensible heat treatment coil 24Y, and the external controller coil 24Z to cover the cooling load. The equipment load heat exchanger 24X, the sensible heat treatment coil 24Y, and the external conditioner coil 24Z have different temperatures of cold water. For example, the equipment load heat exchanger 24X has a sensible heat treatment coil of 17 ° C. 24Y is set to 12 ° C, and the coil 24Z for the external air conditioner is set to 7 ° C. Hereinafter, the apparatus load heat exchanger 24X, the sensible heat treatment coil 24Y, and the external conditioner coil 24Z are also referred to as a load unit 24X, a load unit 24Y, and a load unit 24Z, respectively.

  The air conditioning system 10 is mainly composed of eight cooling towers 42A to 42H and three refrigerators 44X, 44Y, and 44Z. In addition, the number of cooling towers and refrigerators is not limited to the example of this embodiment, For example, a cooling tower may be 7 towers or less, or 9 towers or more, and 2 or less refrigerators are 4 units. It may be the above.

  Although cooling towers 42A-42H omit the internal composition, they collect the fan for forming the rising air current of the outside air in the tower, the sprinkling pipe which sprinkles cooling water in the tower, and the sprinkled cooling water And a water collecting section. According to the cooling towers 42 </ b> A to 42 </ b> H, the cooling water is sprinkled and brought into contact with the outside air, whereby the heat of evaporation is taken away from the cooling water to be cooled. In this embodiment, an example of a hermetic cooling tower will be described. However, an open cooling tower may be used by adding a heat exchanger.

  On the other hand, the three refrigerators 44X, 44Y, and 44Z are apparatuses that generate cooling water having a temperature required for the load units 24X, 24Y, and 24Z, respectively. Refrigerators 44X, 44Y, 44Z are provided with condensers 46X, 46Y, 46Z and evaporators 48X, 48Y, 48Z, respectively. The condensers 46X, 46Y, 46Z and evaporators 48X, 48Y, 48Z It is connected by a circulation path (not shown) so that the refrigerant circulates. Then, the coolant circulates through the condensers 46X, 46Y, 46Z and the evaporators 48X, 48Y, 48Z, thereby cooling the cooling water in the evaporators 48X, 48Y, 48Z. Note that the configurations of the refrigerators 44X, 44Y, and 44Z are not particularly limited, and various configurations such as a turbo type and an absorption type can be adopted. In this embodiment, an example of a turbo type refrigerator will be described. .

  The evaporators 48X, 48Y, and 48Z of the refrigerators 44X, 44Y, and 44Z are connected to the load units 24X, 24Y, and 24Z, respectively. That is, the evaporator 48X is connected to the load portion 24X via the pipes x3 and x4, and the pump 50X is disposed in the pipe x3. By driving the pump 50X, the cooling water is circulated between the evaporator 48X and the load unit 24X. Similarly, the evaporator 48Y is connected to the load portion 24Y via the pipes y3 and y4, and the pump 50Y is disposed in the pipe y3. By driving the pump 50Y, the cooling water is circulated between the evaporator 48Y and the load unit 24Y. Moreover, the evaporator 48Z is connected to the load part 24Z through the piping z3 and z4, and the pump 50Z is arrange | positioned at the piping z3. By driving the pump 50Z, cooling water is circulated between the evaporator 48Z and the load portion 24Z. In this way, the refrigerators 44X, 44Y, 44Z and the load units 24X, 24Y, 24Z are connected one-to-one.

  The condensers 46X, 46Y, and 46Z of the refrigerators 44X, 44Y, and 44Z are connected to the cooling towers 42A to 42H, respectively. The cooling towers 42A to 42H are connected in parallel to the condensers 46X, 46Y, and 46Z. That is, the cooling water outflow pipes a1 to h1 are connected to the cooling towers 42A to 42H, and the pipes a1 to h1 are connected to the main pipe j1. The main pipe j1 is branched into pipes x1, y1, and z1, and then connected to the condensers 46X, 46Y, and 46Z. The condensers 46X, 46Y, and 46Z are connected to the cooling water outflow pipes x2, y2, and z2, and the pipes x2, y2, and z2 are connected to the main pipe j2. The main pipe j2 is branched into pipes a2 to h2, and is connected to watering pipes (not shown) of the cooling towers 42A to 42H. Thereby, the cooling water cooled by the cooling towers 42A to 42H can be circulated and supplied to the condensers 46X, 46Y and 46Z, and the cooling towers 42A to 42H can be used as cooling means for the refrigerators 42X to 42Z. .

  In addition, pumps 52x, 52y, and 52z are respectively disposed in the pipes x1, y1, and z1, and the cooling water is individually supplied to the condensers 46X, 46Y, and 46Z by individually driving and controlling the pumps 52x, 52y, and 52z. Can be circulated and the amount of circulation can be adjusted.

  In addition, three-way valves 54X, 54Y, 54Z are disposed in the pipes x2, y2, z2, respectively, and by operating these three-way valves 54X, 54Y, 54Z, a part of the cooling water flowing through the pipes x2, y2, z2 Flows into the pipes x1, y1, and z1 through the bypass pipes 56X, 56Y, and 56Z, and the flow rate is adjusted.

  Incidentally, the cooling towers 42A to 42H are connected in series to the evaporators 48X, 48Y, and 48Z of the refrigerators 44X, 44Y, and 44Z.

  That is, the pipe x3 is connected to the main pipe j2 through the pipe x6 and is connected to the main pipe j1 through the pipe x5. Therefore, the cooling water flowing through the pipe x3 flows to at least one of the cooling towers 42A to 42H via the pipe x6 and the main pipe j2, and returns to the original pipe x3 via the main pipe j1 and the pipe x5. Thereby, the cooling towers 42A to 42H are connected in series to the evaporator 48X of the refrigerator 44X. A pump 58X is provided in the pipe x6, and the cooling water of the pipe x3 flows into the pipe x6 by driving the pump 58X. In addition, on the piping x3 and the piping x6, on-off valves 60X and 62X are provided immediately downstream of the connecting portions, and on-off valves 63X are provided in the piping x5. By opening and closing these on-off valves 60X, 62X, and 63X, it is possible to select whether or not to flow the cooling water in the pipe x3 to the cooling towers 42A to 42H. Further, a three-way valve 64X is disposed in the pipe x6. By operating the three-way valve 64X, a part of the cooling water flowing through the pipe x6 flows into the pipe x5 via the bypass pipe 66X, and the flow rate is adjusted. .

  Similarly, the pipe y3 is connected to the main pipe j2 through the pipe y6 and is connected to the main pipe j1 through the pipe y5. Therefore, the cooling water flowing through the pipe y3 flows to at least one of the cooling towers 42A to 42H via the pipe y6 and the main pipe j2, and returns to the original pipe y3 via the main pipe j1 and the pipe y5. Thereby, the cooling towers 42A to 42H are connected in series to the evaporator 48Y of the refrigerator 44Y. The pipe y6 is provided with a pump 58Y. By driving the pump 58Y, the cooling water in the pipe y3 flows into the pipe y6. Further, on the piping y3 and the piping y6, on-off valves 60Y and 62Y are provided immediately downstream of the connecting portions, and on the piping y5, an on-off valve 63Y is provided. By opening / closing these on-off valves 60Y, 62Y, 63Y, it is possible to select whether or not to flow the cooling water flowing through the pipe y3 to the cooling towers 42A to 42H. Further, a three-way valve 64Y is disposed in the pipe y6, and by operating the three-way valve 64Y, part of the cooling water flowing through the pipe y6 flows into the pipe y5 via the bypass pipe 66Y, and the flow rate is adjusted. .

  Further, the pipe z3 is connected to the main pipe j2 through the pipe z6 and is connected to the main pipe j1 through the pipe z5. Therefore, the cooling water flowing through the pipe z3 flows to at least one of the cooling towers 42A to 42H via the pipe z6 and the main pipe j2, and returns to the original pipe z3 via the main pipe j1 and the pipe z5. Thereby, the cooling towers 42A to 42H are connected in series to the evaporator 48Z of the refrigerator 44Z. A pump 58Z is provided in the pipe z6. By driving the pump 58Z, the cooling water of the pipe z3 flows into the pipe z6. Further, on the piping z3 and the piping z6, on-off valves 60Z and 62Z are provided immediately downstream of the connecting portions, and on the piping z5, an on-off valve 63Z is provided. By opening / closing these on-off valves 60Z, 62Z, 63Z, it is possible to select whether or not to flow the cooling water flowing through the pipe z3 to the cooling towers 42A to 42H. Further, a three-way valve 64Z is disposed in the pipe z6. By operating the three-way valve 64Z, a part of the cooling water flowing through the pipe z6 flows into the pipe z5 via the bypass pipe 66Z, and the flow rate is adjusted. .

  Thus, in the present embodiment, the cooling towers 42A to 42H can be connected in series to the evaporators 48X, 48Y, 48Z of the refrigerators 44X, 44Y, 44Z. Thereby, the cooling towers 42A to 42H and the refrigerators 44X, 44Y, and 44Z can be used at the same time, and an intermediate operation that is used in combination as a cooling heat source can be performed. That is, the cooling water precooled in any of the cooling towers 42A to 42H can be supplied to the refrigerators 44X, 44Y, and 44Z for cooling. Thereby, the energy consumption of refrigerator 44X, 44Y, 44Z can be reduced.

  Further, according to the present embodiment, the cooling towers 42A to 42H are connected in series to the evaporators 48X, 48Y, and 48Z of the refrigerators 44X, 44Y, and 44Z, and the refrigerant circulation in the refrigerators 44X, 44Y, and 44Z is performed. Is stopped, free cooling operation using only the cooling towers 42 </ b> A to 42 </ b> H as a cold heat source can be performed.

  Incidentally, a plurality of on-off valves 68 for selecting the cooling towers 42A to 42H are disposed in the main pipes j1 and j2 described above. The on-off valve 68 is disposed between the connection parts to which the pipes a1 to h1 are connected on the main pipe j1, or between the connection parts to which the pipes a2 to h2 are connected on the main pipe j2. By opening or closing any of the on-off valves 68, the cooling towers 42A to 42H in which the cooling water circulates can be selected. The opening / closing operation of the opening / closing valve 68 is performed by the control device 70.

  The control device 70 is connected to a sensor 72 that measures the wet bulb temperature of the outside air, and the outside air temperature measurement data is input from the sensor 72. The control device 70 is connected to the load units 24X, 24Y, and 24Z, and load condition data is input from the load units 24X, 24Y, and 24Z. Further, the control device 70 is connected to a driving device (not shown) such as a fan of the cooling towers 42A to 42H, and can individually control the operation and stop of the cooling towers 42A to 42H. The control device 70 obtains the minimum required flow rate of the cooling water by simulation from the outside temperature and load condition data, and determines the cooling towers 42A to 42H to be operated so that the cooling water can be supplied according to the flow rate. . And while operating the cooling towers 42A-42H, the on-off valve 68 is controlled and the cooling water is circulated through the cooling towers 42A-42H. Moreover, about the cooling towers 42A-42H which do not need to flow cooling water, the cooling towers 42A-42H are stopped.

  Next, an operation method of the air conditioning system 10 configured as described above will be described.

  In the summer when the outside air temperature is high, the refrigerator is operated using the refrigerators 44X, 44Y, 44Z as a cold heat source. In the refrigerator operation, the on-off valves 60X, 60Y, 60Z are opened, and the on-off valves 62X, 62Y, 62Z, 63X, 63Y, 63Z are closed. Thereby, a pipe line structure as shown in FIG. 2A is formed. As shown in the figure, the cooling towers 42A to 42H are connected to the condensers 46X, 46Y and 46Z of the refrigerators 44X, 44Y and 44Z, and the cooling water cooled by the cooling towers 42A to 42H is condensed into the condensers 46X, 46Y and 46Z. Circulated and supplied. The evaporators 48X, 48Y, and 48Z of the refrigerators 44X, 44Y, and 44Z are connected to the load units 24X, 24Y, and 24Z, and the cooling water cooled by the evaporators 48X, 48Y, and 48Z is loaded into the load units 24X, 24Y, and 24Z. To be supplied. Therefore, cold can be supplied to the load sections 24X, 24Y, and 24Z using the refrigerators 44X, 44Y, and 44Z as a cold heat source. In the refrigerator operation, all the cooling towers 42A to 42H are used, but the number of the cooling towers 42A to 42H to be used is controlled by opening / closing one of the on-off valves 68 (see FIG. 1). May be. For example, the cooling towers 42A to 42F can be used by closing the on-off valves 68 arranged in the main pipes j1 and j2 between the cooling tower 42F and the cooling tower 42G, and the number of operating units is changed from eight to six. Can be reduced.

  Next, an intermediate operation performed when the outdoor temperature is between summer and winter will be described. The intermediate operation is an operation in which a part of the refrigerators 44X, 44Y, 44Z and the cooling towers 42A to 42H are used as a cooling heat source, and the on-off valves 62X, 62Y, 62Z, 63X, 63Y, 63Z are opened and the on-off valves 60X, 60Y are opened. , Close 60Z. Thus, a part of the cooling towers 42A to 42H and the evaporators 48X, 48Y, and 48Z are connected in series, so that the cooling water is first preliminarily cooled by a part of the cooling towers 42A to 42H, and then the evaporator It is cooled by 48X, 48Y and 48Z and supplied to the load sections 24X, 24Y and 24Z. Therefore, a part of the cooling towers 42A to 42H and the refrigerators 44X, 44Y, 44Z can be used together as a cooling heat source. In the intermediate operation, by connecting the remaining part of the cooling towers 42A to 42H and the condensers 46X, 46Y, 46Z of the refrigerators 44X, 44Y, 44Z, the remaining part of the cooling towers 42A to 42H The cooled cooling water is circulated and supplied to the condensers 46X, 46Y, 46Z, and used for cooling the refrigerators 44X, 44Y, 44Z.

  During the intermediate operation, the number of cooling towers 42 </ b> A to 42 </ b> H to be used can be controlled by opening / closing any of the opening / closing valves 68 (see FIG. 1). As an example, the on-off valve 68 on the main pipes j1 and j2 is closed between the cooling tower 42F and the cooling tower 42G, between the cooling tower 42D and the cooling tower 42E, and between the cooling tower 42C and the cooling tower 42D. As shown in FIG. In this example, two cooling towers 42G and 42H are connected in series to the evaporator 48X of the refrigerator 44X, and two cooling towers 42E and 42F are connected in series to the evaporator 48Y of the refrigerator 44Y. One of 42D is connected in series to the evaporator 48Z of the refrigerator 44Z. Therefore, the number of cooling towers for preliminary cooling can be controlled to two, two, and one. On the other hand, the three cooling towers 42A to 42C are connected to the condensers 46X, 46Y, 46Z of the refrigerators 44X, 44Y, 44Z. Therefore, the number of cooling towers used as cooling means for the refrigerators 44X, 44Y, and 44Z can be controlled to three. In addition, the above is an example, and the number of cooling towers for preliminary cooling and the number of cooling towers for cooling a refrigerator can be individually controlled by changing the position of the closing on-off valve 68.

  In the winter when the outside air temperature is low, free cooling operation is performed using any one of the cooling towers 42A to 42H as a cold heat source. In this free cooling operation, the on-off valves 62X, 62Y, 62Z, 63X, 63Y, 63Z are opened, and the on-off valves 60X, 60Y, 60Z are closed. Thereby, similarly to the intermediate operation, any of the cooling towers 42A to 42H is connected to the load sections 24X, 24Y, and 24Z. At this time, by stopping the operation of the refrigerators 44X, 44Y, and 44Z, the cooling water cooled by the cooling towers 42A to 42H is circulated and supplied to the load sections 24X, 24Y, and 24Z, and the cooling towers 42A to 42H are supplied as a cooling source. The free cooling operation is performed. In addition, the number of cooling towers 42A to 42H to be used can be individually controlled in each system by opening and closing any of the on-off valves 68 during the free cooling operation. Moreover, since it connects to the cooling towers 42A-42H which differ for every system | strain of load part 24X, 24Y, 24Z, the cooling water of the optimal temperature and quantity can be produced | generated for every system | strain.

  The above-described refrigerator operation, intermediate operation, and free cooling operation are automatically switched according to the outside air temperature and load conditions. In addition, switching of the operation mode at that time is not limited to switching simultaneously in all the systems of the load units 24X, 24Y, and 24Z, and may be controlled individually in each system. For example, while the intermediate operation and the free cooling operation are performed by the system of the load units 24X and 24Y, the refrigerator operation may be performed by the system of the load unit 24Z. In this case, since the precooling cooling tower and the free cooling cooling tower are unnecessary in the system of the load unit 24Z, the number of cooling towers used in the system of the load unit 24X and the load unit 24Y can be increased.

  Various combinations of operation modes and the number of cooling towers at that time simulate various patterns using the outside air temperature and load conditions as input values. From the result, the minimum necessary amount of cooling is obtained, and the cooling towers 42A to 42H are selected and operated so as to cover this amount of cooling. Thereby, the energy consumption as the whole system can be reduced.

  As described above, according to the present embodiment, the number of cooling towers in each operation mode of the refrigerator operation, intermediate operation, and free cooling operation can be controlled. By operating, energy consumption can be reduced.

  In the above-described embodiment, the refrigerators 44X, 44Y, and 44Z may be turbo refrigerators and may be inverter controlled. In this case, the energy consumption of the refrigerators 44X, 44Y, 44Z can be reduced.

  In the above-described embodiment, the rotational speeds of the pumps 50X, 50Y, 50Z, 52X, 52Y, 52Z, 58X, 58Y, and 58Z may be controlled by an inverter. Thereby, the flow volume of a cooling water can be controlled and the energy consumption spent for the circulation of a cooling water can be reduced.

  In addition, embodiment mentioned above is an example which connected the piping so that each cooling tower number of load part 24X, 24Y, 24Z might be two units, two units, and one unit at the time of an intermediate | middle operation and free cooling operation. However, the connection of piping is not limited to this, and various modes are possible. For example, FIG. 3 is an example in which the number of cooling towers of the load unit 24X can be increased. In the air conditioning system of the figure, bypass pipes 80 and 82 are provided, one end (right end in the figure) of the pipe 80 is connected to the pipe x6, and the other end (left end in the figure) is branched. Each is connected to the main pipe j2 so as to be able to communicate with the pipes a2, b2, and c2. One end (right end in the figure) of the pipe 82 is connected to the pipe x5, and the other end (left end in the figure) is branched, and each is connected to the main pipe j1 so as to be able to communicate with the pipes a1, b1, and c1. The In addition, an opening / closing valve 84 is provided in each of the branch pipe portion of the pipe 80 and the branch pipe portion of the pipe 82, and the cooling towers 42A, 42B, 42C are respectively connected to the pipes x5, x6 by opening and closing the on-off valve 84. Is communicated with or blocked from the load section 24X. Each on-off valve 84 is electrically connected to the control device 70 and is controlled to be opened and closed by the control device 70. Therefore, the control device 70 can select whether or not the cooling towers 42A, 42B, and 42C are operated for the load unit 24X.

  In the air conditioning system of FIG. 3 configured as described above, the two cooling towers 42A, 42B, 42C, 42G, and 42H are loaded while operating the two cooling towers 42E and 42F for the load unit 24Y during free cooling. The number of cooling towers for the load unit 24X can be controlled by 0 to 5 units. Moreover, if the free cooling operation of the load part 24Y and the load part 24Z is stopped, the number of cooling towers for the load part 24X can be controlled by 0 to 8. Therefore, according to the present embodiment, the number of cooling towers for the load section 24X can be increased, and the free cooling operation can be performed over a long period of time.

  FIG. 4 shows a modification of the air conditioning system 10 of FIG. The air conditioning system shown in the figure has a system configuration in which intermediate operation and free cooling operation are not performed in the load section 24Z. That is, the air conditioning system of FIG. 4 is compared with the air conditioning system 10 of FIG. 1, the cooling tower 42 </ b> D, piping d <b> 1, d <b> 2, z <b> 5, z <b> 6, on-off valves 60 </ b> Z, 62 </ There is no 66Z, and the cost is reduced. Further, the connection position between the pipe y5 and the main pipe j1 and the connection position between the pipe y6 and the main pipe j2 are different.

  As an example of the operation of the air conditioning system of FIG. 4 configured as described above, the refrigerator is operated in all the load sections 24X, 24Y, 24Z, for example, at a time when the outside air temperature is high (for example, from June to September). At that time, the number of cooling towers is controlled to 6 units (42A, 42B, 42C, 42E, 42F, 42G) particularly at a time when the outside air temperature is high (eg, July and August), and the outside air temperature is slightly lower than that. (For example, in June and September), the number of cooling towers is controlled to five (42A, 42B, 42C, 42E, 42F). The number of cooling towers is controlled by controlling the on-off valve 68 and the cooling towers 42 </ b> A to 42 </ b> H by the control device 70 as in the above-described air conditioning system of FIG. 1.

  At the time when the outside air temperature is slightly lower than when the refrigerator is operated (for example, in May and October), the refrigerator 24 is operated with the load units 24Y and 24Z, while the load unit 24X is switched to the free cooling operation. At that time, the three cooling towers 42A to 42C communicate with the condensers 46Y and 46Z of the refrigerators 44Y and 44Z, and are used for the refrigerator operation of the load units 24Y and 24Z. Further, the four cooling towers 42E to 42H are used for the free cooling operation of the load section 24X.

  During the time when the outside air temperature decreases (for example, from November to April), free cooling is performed in the load sections 24X and 24Y. At that time, the number of cooling towers may be changed according to the outside air temperature. Specifically, when the outside air temperature is slightly high (for example, in November and April), the number of cooling towers of the load unit 24Y is increased to five (42A, 42B, 42C, 42E, 42F), and the load unit 24X Reduce the number of cooling towers to 2 (42G, 42H). In addition, when the outside air temperature is low (for example, from December to March), the number of cooling towers in the load section 24Y is reduced to four (42A, 42B, 42C, 42E), and the number of cooling towers in the load section 24X is three. (42F, 42G, 42H).

  In addition, it is good to determine said driving | operation pattern based on the external air wet bulb temperature and the load conditions of the load parts 24X-24Z. For example, the switching control of the number of units using the energy consumption as an evaluation function and the optimization calculation of the system may be performed according to the outside wet bulb temperature and the load condition. Further, the calculation results may be controlled as a table.

(Second Embodiment)
FIG. 5 is a system diagram schematically showing the configuration of the air conditioning system 11 of the second embodiment. The air conditioning system 11 shown in the figure is a system that air-conditions a single load unit 24. In addition, about the member which has the same structure and effect | action as 1st Embodiment shown in FIG. 1, the same code | symbol (except for XZ) is attached | subjected and the description is abbreviate | omitted.

  The air conditioning system 11 illustrated in FIG. 5 includes one refrigerator 44 and three cooling towers 42A to 42C. The condenser 46 of the refrigerator 44 is connected to each cooling tower 42 </ b> A to 42 </ b> C, and the cooling towers 42 </ b> A to 42 </ b> C are connected in parallel to the condenser 46. That is, the cooling water outflow pipes a1 to c1 are connected to the cooling towers 42A to 42C. After the pipes a1 to c1 are connected to the main pipe j1, the main pipe j1 is connected to the condenser 46. The main pipe j2 connected to the condenser 46 is branched into cooling water inflow pipes a2 to c2, and the pipes a2 to c2 are connected to the cooling towers 42A to 42C. The main pipe j1 is provided with a pump 52. By driving the pump 52, the cooling water circulates between the cooling towers 42A to 42C and the condenser 46, and the circulation amount thereof is adjusted. Is done. The main pipe j2 is provided with a three-way valve 54, and a part of the cooling water flowing through the main pipe j2 can be flowed to the main pipe j1 through the bypass pipe 56 to adjust the flow rate.

  The evaporator 48 of the refrigerator 44 is connected to the load unit 24 via the pipes k3 and k4. A pump 52 is connected to the pipe k3. Thereby, the cooling water cooled by the evaporator 48 can be circulated and supplied to the load section 24.

  The cooling towers 42 </ b> A to 42 </ b> C are connected to the evaporator 48 in series. That is, the pipe k3 is connected to the main pipe j2 through the pipe k6 and is connected to the main pipe j1 through the pipe k5. Therefore, the cooling water flowing through the pipe k3 flows to at least one of the cooling towers 42A to 42C via the pipe k6 and the main pipe j2, and returns to the original pipe k3 via the main pipe j1 and the pipe k5. Thereby, the cooling towers 42 </ b> A to 42 </ b> C are connected in series to the evaporator 48 of the refrigerator 44. The pipe k6 is provided with a pump 58, and by driving the pump 58, the cooling water of the pipe k3 flows into the pipe k6. In addition, on the piping k3 and the piping k6, on-off valves 60 and 62 are provided immediately downstream of the connecting portions. In addition, an opening / closing valve 63 is provided in the pipe k5. By opening and closing these on-off valves 60, 62, and 63, it is possible to select whether or not to flow the cooling water in the pipe k3 to the cooling towers 42A to 42C. Furthermore, a three-way valve 64 is provided in the pipe k6, and by operating the three-way valve 64, a part of the cooling water flowing through the pipe k6 flows into the pipe k5 via the bypass pipe 66, and the flow rate is adjusted. .

  A plurality of on-off valves 68 for selecting the cooling towers 42A to 42C are provided in the main pipes j1 and j2 described above. The on-off valve 68 is disposed between the connection parts to which the pipes a1 to c1 are connected on the main pipe j1, or between the connection parts to which the pipes a2 to c2 are connected on the main pipe j2. By opening or closing any of the on-off valves 68, the cooling towers 42A to 42C in which the cooling water circulates can be selected. The opening / closing operation of the opening / closing valve 68 is performed by the control device 70.

  The control device 70 is connected to a sensor 72 that measures the wet bulb temperature of the outside air, and the outside air temperature measurement data is input from the sensor 72. The control device 70 is connected to the load unit 24, and load condition data is input from the load unit 24. Further, the control device 70 is connected to a driving device (not shown) such as a fan of the cooling towers 42A to 42C, and can control the operation and stop of the cooling towers 42A to 42C. The control device 70 obtains the minimum required flow rate of the cooling water by simulation from the outside temperature and load condition data, and determines the cooling towers 42A to 42C to be operated so that the cooling water corresponding to the flow rate can be supplied. . And while operating the cooling towers 42A-42C, the on-off valve 68 is controlled and the cooling water is circulated through the cooling towers 42A-42C. Moreover, about the cooling towers 42A-42C which do not need to flow cooling water, the cooling towers 42A-42C are stopped.

  Next, an operation method of the air conditioning system 11 configured as described above will be described.

  In the summer when the outside air temperature is high, the refrigerator is operated using the refrigerator 44 as a cold source. In the refrigerator operation, the on-off valve 60 is opened and the on-off valves 62, 63 are closed. Thereby, a pipe line structure as shown in FIG. 6A is formed. As shown in the figure, the cooling towers 42A to 42C are connected to the condenser 46 of the refrigerator 44, and the cooling water cooled by the cooling towers 42A to 42C is circulated and supplied to the condenser 46. The evaporator 48 and the load unit 24 are connected, and the cooling water cooled by the evaporator 48 is supplied to the load unit 24. Therefore, cold can be supplied to the load unit 24 using the refrigerator 44 as a cold source. At this time, it is also possible to control the number of cooling towers 42 </ b> A to 42 </ b> C to be used by opening / closing one of the opening / closing valves 68.

  In the intermediate operation, the on-off valves 62 and 63 are opened and the on-off valve 60 is closed. As a result, a part of the cooling towers 42A to 42C and the evaporator 48 are connected in series, so that the cooling water is first precooled by a part of the cooling towers 42A to 42C and then cooled by the evaporator 48. , And supplied to the load unit 24. Therefore, a part of the cooling towers 42A to 42C and the refrigerator 44 can be used together as a cold heat source. In the intermediate operation, the remaining part of the cooling towers 42A to 42C and the condenser 46 of the refrigerator 44 are connected, and the cooling water cooled by the remaining part of the cooling towers 42A to 42C is supplied to the condenser 46. It is circulated and used to cool the refrigerator 44. Also during the intermediate operation, the number of cooling towers 42A to 42C to be used can be controlled by opening or closing any of the on-off valves 68. As an example, FIG. 6B shows an example in which the on-off valve 68 is closed between the cooling tower 42A and the cooling tower 42B and between the cooling tower 42B and the cooling tower 42C. In this example, since one of the cooling towers 42C is connected in series to the evaporator 48 of the refrigerator 44, the number of preliminary cooling cooling towers is one. Further, since one of the cooling towers 42A is connected to the condenser 46 of the refrigerator 44, the number of cooling towers used as the cooling means of the refrigerator 44 is controlled to one. Note that the above is an example, and the number of pre-cooling cooling towers and the number of cooling tower cooling cooling towers can be individually controlled by changing the position of the closing on-off valve 68.

  In the winter when the outside air temperature is low, free cooling operation is performed using any one of the cooling towers 42A to 42C as a cold heat source. In this free cooling operation, the on-off valve 60 is closed. Thereby, the cooling towers 42 </ b> A to 42 </ b> C are connected to the load unit 24 as in the intermediate operation. At this time, the operation of the refrigerator 44 is stopped. Therefore, the cooling water cooled by the cooling towers 42A to 42C is circulated and supplied to the load section 24, and a free cooling operation is performed using the cooling towers 42A to 42C as a cold heat source. In addition, the number of cooling towers 42A to 42C to be used can be controlled by opening / closing any of the opening / closing valves 68 during the free cooling operation. For example, as shown in FIG. 6C, two cooling towers 42B and 42C can be used for free cooling operation.

  As described above, according to the present embodiment, the number of cooling towers in each operation mode of the refrigerator operation, intermediate operation, and free cooling operation can be controlled, so that the minimum number of cooling towers 42A to 42C are operated. As a result, energy consumption can be reduced.

  In the first and second embodiments described above, the number of operating cooling towers is controlled. However, the number of cooling water circulation destinations can be changed while all the cooling towers are operating. Also good.

(Third embodiment)
FIG. 7 is a system diagram schematically showing the configuration of the air conditioning system 10 of the third embodiment. The air conditioning system 10 shown in the figure is a system that air-conditions one system of the load unit 24. In addition, about the member which has the structure and effect | action similar to 1st Embodiment shown in FIG. 1, the same code | symbol may be attached | subjected and the description may be abbreviate | omitted.

  Compared with the first embodiment, except for the number of cooling towers and refrigerators, in the third embodiment, the cooling tower is an open type cooling tower provided with a heat exchanger, and the load section is one system.

  The air conditioning system 10 shown in FIG. 7 includes two refrigerators 44X and 44Y, five cooling towers 42A to 42E, and free cooling heat exchangers 80X and 80Y connected to the cooling towers 42A to 42E. . In the present embodiment, the cooling towers 42A to 42E are configured as open cooling towers. The open-type cooling tower has a water spray pipe for spraying the cooling water and a water collecting section for collecting the sprayed cooling water. The cooling water is sprayed from the water spray pipe and comes into contact with the outside air, thereby removing the heat of evaporation. Then it is cooled. When the cooling towers 42A to 42E are open-type cooling, the cooling water temperature of the refrigerators 44X and 44Y is lower than that of the sealed cooling tower in the operation with the refrigerators 44X and 44Y, and the results of the refrigerators 44X and 44Y are obtained. The coefficient is improved and energy is saved. Further, the open type cooling tower can reduce the installation area and cost as compared with the closed type cooling tower.

  The connection relationship between the heat exchangers 80X and 80Y, the cooling towers 42A to 42E, and the load unit 24 will be described. The cooling towers 42A to 42E are connected to pipings a1 to e1 for cooling water outflow, and the pipings a1 to e1 are connected to the main piping j1. The main pipe j1 is branched into pipes x5 and y5, and then connected to the heat exchangers 80X and 80Y.

  The cooling water outflow pipes x6 and y6 are connected to the heat exchangers 80X and 80Y, and the pipes x6 and y6 are connected to the main pipe j2. The main pipe j2 is branched into pipes a2 to e2, and connected to watering pipes (not shown) of the cooling towers 42A to 42E. Pumps 59x and 59y are disposed in the pipes x5 and y5, respectively. By individually driving and controlling the pumps 59x and 59y, the cooling water is individually circulated between the heat exchangers 80X and 80Y and the cooling towers 42A to 42E.

  A pipe x7 and a pipe x8 are connected to the heat exchanger 80X. The pipe x7 is connected to the pipe x3, and the pipe x8 is connected to the pipes x3 and x4. Further, the pipe y7 and the pipe y8 are connected to the heat exchanger 80Y. The pipe y7 is connected to the pipe y3, and the pipe y8 is connected to the pipe y4. And the heat exchanger 80X is connected to the load part 24 via piping x3, x4, x7, x8. The heat exchanger 80Y is connected to the load unit 24 through the pipes y3, y4, y7, and y8.

  A pump 58X is disposed in the pipe x7, and a pump 58Y is disposed in the pipe y7. By driving the pump 58X, cold water can be circulated between the heat exchanger 80X and the load unit 24. Similarly, by driving the pump 58Y, cold water can be circulated between the heat exchanger 80Y and the load section 24.

  An open / close valve 60X is provided in the pipe x3, an open / close valve 62X is provided in the pipe x7, and an open / close valve 63X is provided in the pipe x8. By opening and closing these on-off valves 60X, 62X, and 63X, it is selected whether the cold water in the pipes x3 and x4 flows to the heat exchanger 80X or the refrigerator 44X.

  Similarly, an open / close valve 60Y is provided in the pipe y3, an open / close valve 62Y is provided in the pipe y7, and an open / close valve 63Y is provided in the pipe y8. By opening / closing these on-off valves 60Y, 62Y, 63Y, it is selected whether the cold water in the pipes y3, y4 flows to the heat exchanger 80y or the refrigerator 44Y.

  Next, the connection relationship between the refrigerators 44X and 44Y, the cooling towers 42A to 42E, and the load unit 24 will be described. The refrigerators 44X and 44Y include condensers 46X and 46Y and evaporators 48X and 48Y, respectively. The evaporator 48X is connected to the load unit 24 through the pipes x3 and x4. Further, the evaporator 48Y is connected to the load unit 24 through the pipes y3 and y4.

  The condensers 46X and 46Y of the refrigerators 44X and 44Y are connected to the cooling towers 42A to 42E, respectively. The cooling towers 42A to 42E are connected in parallel to the condensers 46X and 46Y. The cooling towers 42A to 42E are connected to pipings a1 to e1 for cooling water outflow, and the pipings a1 to e1 are connected to the main piping j1. The main pipe j1 is branched into pipes x1 and y1, and then connected to the condensers 46X and 46Y. The condensers 46X and 46Y are connected to the cooling water outflow pipes x2 and y2, and the pipes x2 and y2 are connected to the main pipe j2. The main pipe j2 is branched into pipes a2 to e2, and connected to watering pipes (not shown) of the cooling towers 42A to 42E. Thereby, the cooling water cooled by the cooling towers 42A to 42E can be circulated and supplied to the condensers 46X and 46Y, and the cooling towers 42A to 42E can be used as cooling means for the refrigerators 42X and 44Y.

  Pumps 52x and 52y are disposed in the pipes x1 and y1, respectively. By individually controlling the driving of the pumps 52x and 52y, the cooling water is individually circulated through the condensers 46X and 46Y, and the circulation amount is adjusted.

  The evaporator 48X of the refrigerator 44X is connected to the load unit 24 via the pipes x3 and x4. A pump 50 </ b> X is disposed in the pipe x <b> 3, and cold water is circulated between the evaporator 48 </ b> X and the load unit 24 by driving the pump 50 </ b> X. Similarly, the evaporator 48Y of the refrigerator 44Y is connected to the load unit 24 via the pipes y3 and y4. A pump 50Y is disposed in the pipe y3, and cold water is circulated between the evaporator 48Y and the load unit 24 by driving the pump 50Y.

  The pipes a1 to e1 are connected to the main pipe j1, the pipes a2 to e2 are connected to the main pipe j2, and the cooling towers 42A to 42E described above are connected in parallel with the refrigerators 44X and 44Y. Similarly, the cooling towers 42A to 42E are connected in parallel with the heat exchangers 80X and 80Y. In the present embodiment, the main pipes j1 and j2 form a common cooling water circulation path for the heat exchangers 80X and 80Y and the refrigerators 44X and 44Y.

  A plurality of on-off valves 68 for selecting the cooling towers 42A to 42E are disposed in the main pipes j1 and j2 described above. The on-off valve 68 is disposed between the connection parts to which the pipes a1 to e1 are connected on the main pipe j1, or between the connection parts to which the pipes a2 to e2 are connected on the main pipe j2. By opening or closing any of the on-off valves 68, the cooling towers 42A to 42E through which the cooling water circulates can be selected. The opening / closing operation of the opening / closing valve 68 is performed by the control device 70.

  The control device 70 is connected to a sensor 72 that measures the wet bulb temperature of the outside air, and the outside air temperature measurement data is input from the sensor 72. The control device 70 is connected to the load unit 24, and load condition data is input from the load unit 24. Further, the control device 70 is connected to a driving device (not shown) such as a fan of the cooling towers 42A to 42E, and can control the operation and stop of the cooling towers 42A to 42E. The control device 70 determines the cooling towers 42A to 42E to be operated by simulation from the outside temperature and load condition data. And while operating the cooling towers 42A-42E, the on-off valve 68 is controlled and a cooling water is circulated through the cooling towers 42A-42E. Moreover, about the cooling towers 42A-42E which do not need to flow cooling water, the cooling towers 42A-42E are stopped.

  Further, the control device 70 controls the fans of the cooling towers 42A to 42E and the inverters provided in the pumps 50X, 50Y, 52X, 52Y, 58X, 58Y, 59X, 59Y, and the total consumption of the refrigerator, the fans and the pumps The power is driven to a minimum value.

  The control is performed as follows as an example. First, the outside air wet bulb temperature, the load, the cooling water temperature at the outlets of the cooling towers 42A to 42E, and the cold water temperature at the outlets of the heat exchangers 80X and 80Y are set as input values, and the fans and pumps 50X of the cooling towers 42A to 42E. Input value data is input to a simulator that performs a simulation for obtaining a total value of power consumption, such as 50Y, 52X, 52Y, 58X, 58Y, 59X, and 59Y. At this time, the input value data is input to the simulator while changing the cooling water temperature and the input value of the cooling water temperature. From the simulation results, the frequency (number of rotations) of the fans and pumps 50X, 50Y, 52X, 52Y, 58X, 58Y, 59X, and 59Y of the cooling towers 42A to 42E that minimize the total power consumption is acquired as the optimum value. . The actual cooling water temperature and the cooling water temperature are set to the acquired optimum value by the control device 70. The control device 70 controls the inverters of the cooling water pumps (52X, 52Y, 59X, 59Y) and the cooling water pumps (50X, 50Y) in response to changes in the wet bulb temperature state of the outside air and the cooling load. Energy saving is realized by changing the flow rate.

  In the system operating the refrigerator, the cooling water pump frequency that minimizes the total power consumption using a simulator that calculates the total power consumption of the refrigerator, cooling tower, cooling water pump, and cold water pump Get cooling water temperature and cooling water temperature, control cooling tower fan and pump.

  Next, an operation method of the air conditioning system 10 configured as described above will be described. In the summer when the outside air temperature is high, the refrigerator is operated using the refrigerators 44X and 44Y as a cold heat source. In the refrigerator operation, the on-off valves 60X and 60Y are opened and the on-off valves 62X, 62Y, 63X and 63Y are closed. Thereby, a pipe line structure as shown in FIG. 8A is formed. As shown in the figure, the cooling towers 42A to 42E are connected to the condensers 46X and 46Y of the refrigerators 44X and 44Y. By driving the pumps 52X and 52Y, the cooling water cooled by the cooling towers 42A to 42E is circulated and supplied to the condensers 46X and 46Y. The evaporators 48X and 48Y of the refrigerators 44X and 44Y and the load unit 24 are connected. By driving the pumps 50X and 50Y, the cold water cooled by the evaporators 48X and 48Y is supplied to the load unit 24. Therefore, cold can be supplied to the load unit 24 using the refrigerators 44X and 44Y as a cold heat source. At this time, it is also possible to control the number of cooling towers 42 </ b> A to 42 </ b> E to be used by opening / closing one of the opening / closing valves 68.

  In the winter when the outside air temperature is low, free cooling operation is performed using any one of the cooling towers 42A to 42E as a cold heat source. In this free cooling operation, the pumps 50X and 50Y are stopped, the on-off valves 60X and 60Y are closed, and the on-off valves 62X, 62Y, 63X and 63Y are opened. Since the pressure loss of the on-off valves 63X, 63Y is smaller than the pressure loss of the pumps 50X, 50Y, the cold water from the heat exchangers 80X, 80Y flows through the pipes x8, y8, and further to the load section 24 via the on-off valves 63X, 63Y. Flowing. Thereby, the cooling towers 42 </ b> A to 42 </ b> E are connected to the heat exchangers 80 </ b> X and 80 </ b> Y, and the heat exchangers 80 </ b> X and 80 </ b> Y are connected to the load unit 24. At this time, the operation of the refrigerators 44X and 44Y is stopped. By driving the pumps 59X and 59Y, the cooling water cooled by the cooling towers 42A to 42E is circulated and supplied to the heat exchangers 80X and 80Y. By driving the pumps 58X and 58Y, the cold water cooled by the heat exchangers 80X and 80Y is supplied to the load unit 24. In addition, the number of cooling towers 42A to 42E to be used can be controlled by opening / closing any of the on-off valves 68 during the free cooling operation. For example, in FIG. 8B, three cooling towers 42C to 42E can be used for the free cooling operation.

  Next, an intermediate operation performed when the outdoor temperature is between summer and winter will be described with reference to FIG. In the intermediate operation, the cooling tower is switched between the refrigerator side and the free-cooling heat exchanger side. That is, the operation is performed using the refrigerators 44X and 44Y and a part of the cooling towers 42A to 42E as a cold heat source. The on-off valve 68 on the inlet side and the on-off valve 68 on the outlet side between the cooling tower 42B and the cooling tower 42C are closed. The on-off valve 68 between the cooling tower 42A and the cooling tower 42B and the on-off valve 68 between the cooling tower 42C and the cooling tower 42D are switched to close depending on the outside air temperature and load conditions. The on-off valves 60X, 63X, 60Y, 63Y are closed, and the on-off valves 62X, 62Y are opened. Thereby, the path | route which lets water flow to a refrigerator is formed in the back | latter stage of the heat exchanger for free cooling. That is, the cold water flows through the pipes x3 and x7, the heat exchanger 80x, the pipes x8, x3, and x4 and is circulated and supplied to the evaporator 48x as indicated by arrows. Similarly, the cold water flows through the pipes y3 and y7, the heat exchanger 80y, the pipes y8, y3, and y4 and is circulated and supplied to the evaporator 48y as indicated by arrows.

  As described above, according to the present embodiment, the number of cooling towers in each operation mode of the refrigerator operation, intermediate operation, and free cooling operation can be controlled, so that the minimum number of cooling towers 42A to 42E are operated. As a result, energy consumption can be reduced.

  Further, the piping system including the on-off valves 63X and 63Y is eliminated, that is, the piping connecting the piping x3 and the piping x4 and the piping connecting the piping y3 and the piping y4 are eliminated, and in the same way as in FIG. In the case of operation, cold water may be passed through the refrigerator to cope with the operation of the refrigerator, intermediate operation, and free cooling operation.

  FIG. 10 shows a modification of the air conditioning system 10 of FIG. The air conditioning system shown in FIG. 10 has a piping system that can switch a cooling water system that passes water for each cooling tower.

  As shown in FIG. 10, the main pipe j1 is connected to the refrigerators 44X and 44Y via pipes x2 and y2. The main pipe j2 is connected to the refrigerators 44X and 44Y through the pipes x1 and y1. Pipes a1 to e1 are connected to the main pipe j1, and the cooling towers 42A to 42E and the main pipe j1 are connected via the pipes a1 to e1. On-off valves 68 are provided in the pipes a1 to e1, respectively. Pipes a2 to e2 are connected to the main pipe j2, and the cooling towers 42A to 42E and the main pipe j2 are connected via the pipes a2 to e2. On-off valves 68 are provided in the pipes a2 to e2, respectively.

  On the other hand, the main pipe j3 is connected to the heat exchangers 80X and 80Y through the pipes x5 and y5. The main pipe j4 is connected to the heat exchangers 80X and 80Y through the pipes x6 and y6. Pipes a3 to e3 are connected to the main pipe j3, and the cooling towers 42A to 42E and the main pipe j3 are connected via the pipes a3 to e3. On-off valves 68 are provided in the pipes a3 to e3, respectively. Pipes a4 to e4 are connected to the main pipe j4, and the cooling towers 42A to 42E and the main pipe j4 are connected via the pipes a4 to e4. On-off valves 68 are provided in the pipes a4 to e4, respectively.

  In the present embodiment, a circulation path is formed between the refrigerators 44X and 44Y and the cooling towers 42A to 42E by the main pipes j1 and j2, and the heat exchangers 80X and 80Y and the cooling towers 42A to 42A are formed by the main pipes j3 and j4. A circulation path is formed with 42E.

  By opening or closing any of the plurality of on-off valves 68 provided in the pipes a1 to e1, a2 to e2, a3 to e3, and a4 to e4, the cooling water is supplied to the refrigerators 44X and 44Y for each of the cooling towers 42A to 42E. It is possible to select either of the heat exchangers 80X and 80Y for free cooling.

  By adopting such a configuration, it is possible to reduce the number of on-off valves through which the cooling water passes when the cooling water is passed through the pipe. Thereby, piping resistance becomes small and the motive power of a pump can be reduced. In the present embodiment, the cooling water from the cooling towers 42A to 42E can be passed through the main pipe j1 or j3 only by passing through one on-off valve 68.

  On the other hand, in the configuration shown in FIG. 7, in the cooling tower farther from the heat exchanger, the number of on-off valves to the heat exchanger is large, and the pipe resistance is increased. For example, the cooling water in the cooling tower 42A passes through the plurality of on-off valves 68 and is passed to the heat exchangers 80X and 80Y.

  Moreover, in the air conditioning system 10 shown in FIG. 10, water can be passed regardless of the order from the heat exchanger or the refrigerator. Therefore, the degree of freedom in selecting the cooling tower to be switched to the heat exchanger system and the refrigerator system is increased. The system at the inlet / outlet of the cooling tower may be a branch pipe.

  DESCRIPTION OF SYMBOLS 10 ... Air conditioning system, 12 ... Clean room equipment, 24X, 24Y, 24Z ... Load part, 42A-42H ... Cooling tower, 44X, 44Y, 44Z ... Refrigerator, 46X, 46Y, 46Z ... Condenser, 48X, 48Y, 48Z ... Evaporator, 68 ... Open / close valve

Claims (3)

A plurality of cooling towers for cooling the cooling water;
A plurality of refrigerators having a condenser and an evaporator;
Circulating the cooling water cooled by the cooling tower to the condenser, and circulating the cooling water cooled by the evaporator to the air conditioning load section;
A circulation line for free cooling operation that circulates the cooling water cooled in the cooling tower to the air conditioning load section;
Line switching means for switching between the freezer operation circulation line and the free cooling operation circulation line, and adjusting the number of cooling towers connected to the free cooling operation circulation line;
An intermediate operation circulation line connecting the plurality of cooling towers in series with the evaporator of the refrigerator;
The line switching means performs line switching including the intermediate operation circulation line, the number of cooling towers connected to the intermediate operation circulation line, and the refrigerator connected to the condenser side of each refrigerator. Change the number of cooling towers in common ,
A control device for controlling the line switching means according to an outside air temperature and an air conditioning load condition and individually controlling the operation and stop of the plurality of cooling towers;
An air conditioning system characterized by comprising The air conditioning system according to claim 1 , wherein the refrigerator is a turbo refrigerator that is inverter-controlled. 3. A pump for circulating cooling water cooled by the plurality of cooling towers or the refrigerator, and the pump controls the flow rate of the cooling water by controlling the number of rotations. The air conditioning system described in.

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