JP2011226680A - Cooling water producing facility - Google Patents

Abstract

The present invention provides a cooling water production facility capable of preventing a decrease in cooling capacity even at a low flow rate of cooling water in a cooling tower.
A cooling water production facility 10 according to the present invention includes two cooling towers 12 and 14, a cooling water pump 18, a load section 20, and a pipe that distributes the cooling water to the cooling towers 12 and 14 and passes water in parallel. The system 22 and the cooling towers 12 and 14 are provided with a piping system 24 for passing cooling water in series, and the piping system 24 is provided with a cooling water pump 26. When the cooling water flow rate is low, the cooling water pumps 18 and 26 are stopped. Series operation and parallel operation of the cooling towers 12 and 14 are performed by starting and stopping the cooling water pumps 18 and 26. According to this cooling water production facility 10, the cooling towers 12 and 14 are connected in parallel at the maximum load, and the cooling water pump 26 is switched on and off to be connected in series at a low flow rate of the cooling water. The valves 28A and 28B are opened and closed.
[Selection] Figure 2

Description

  The present invention relates to a cooling water manufacturing facility, and more particularly to a cooling water manufacturing facility installed in a factory such as a semiconductor factory that requires a cooling heat source throughout the year.

  Patent Document 1 proposes an increase in the size of a cooling tower and a reduction in cooling water temperature by increasing the number of cooling towers.

JP 2005-214608 A

  However, in conventional cooling water production facilities, if the number of general cooling towers for refrigeration units is increased to increase the heat transfer area, the cooling water production temperature can be lowered under the same outside air conditions. When the amount of water is small, it becomes difficult to drop the cooling water uniformly, and there is a problem that a predetermined cooling capacity cannot be maintained.

  In order to save energy by increasing the size of the cooling tower and changing the cooling water flow rate, it is necessary to maintain the heat transfer performance and reduce the air volume and flow rate even when the cooling water flow rate is low. However, since the specifications of the cooling tower for air conditioning are limited for each model, it is difficult to cope with a wide range of flow rate changes.

  This invention is made | formed in view of such a situation, and it aims at providing the cooling water manufacturing equipment which can prevent the fall of a cooling capability even at the time of the low flow volume of the cooling water in a cooling tower.

  In order to achieve the above object, the present invention provides a plurality of cooling towers that cool the cooling water by exchanging heat between the cooling water and the outside air, and the cooling water cooled by the plurality of cooling towers. A first pump that circulates between the first and second load sections, a first piping system that distributes the cooling water that has passed through the load section to the plurality of cooling towers, and passes water in parallel, and the plurality of cooling sections A cooling water production facility comprising: a second piping system for passing cooling water through the tower in series; and a second pump for passing cooling water through the second piping system. To do.

  The present invention provides a system capable of passing cooling water in series with a piping system connecting two or more cooling towers in parallel, and operating the cooling tower water flow system in parallel in response to changes in the flow rate of the cooling water. By switching to the serial operation, the cooling capacity is prevented from being lowered even at a low flow rate of the cooling water in the cooling tower.

  According to the present invention, it is possible to perform serial operation and parallel operation of a plurality of cooling towers by starting and stopping the first pump and the second pump. In addition, by installing the second pump in the vicinity of the cooling tower and bypassing it, the pump head can be reduced, and the conveyance power during the bypass can be reduced.

  In this invention, it has a function which changes the rotation speed of the said 1st pump and a 2nd pump, and a calculator, A said 1st pump is drive | operated by the instruction | command of the said calculator, and several cooling towers It is preferable to perform an operation of passing water in parallel and an operation of operating the first pump and the second pump to pass water through the cooling tower in series.

  According to the present invention, by controlling the cooling water flow rate of the cooling tower to be equal to or higher than the minimum flow rate and performing the series operation when the flow rate is reduced, the distribution of the spray water of the cooling tower filler becomes non-uniform. It can prevent, and it becomes possible to prevent the fall of cooling performance by preventing the reduction of a heat-transfer area. When the series operation is performed at a cooling water flow rate of 100%, the power of the pump is increased as compared with the parallel operation, but the increase in the pump power can be reduced by performing the series operation only at a low flow rate. Moreover, it becomes possible to expand the cooling water flow rate range in which the heat transfer area can be maintained, to prevent the air volume and increase of the cooling tower, and to reduce fan power of the cooling tower.

  In the present invention, it has cooling load measuring means, and the computing unit uses the cooling load and wet bulb temperature measurement values measured by the cooling load measuring means as input conditions, and the plurality of cooling towers, the first The cooling water flow rate, the cooling water temperature, and the operation state of the cooling tower are calculated so that the energy consumption of the pump and the second pump is minimized, and the first pump and the second pump are started and stopped. It is preferable to switch between the serial operation and the parallel operation of the cooling tower and to control the rotational speed of the first pump and the second pump.

  According to the present invention, the energy consumption amount of the cooling water production facility can be made closer to the minimum value in accordance with the outside wet bulb temperature and the cooling load. In addition, the cooling tower can be switched between parallel operation and series operation and the cooling water variable flow rate can be changed so as to reduce the energy consumption.

  Also, during free cooling operation, by increasing the heat transfer area of the cooling tower, the cooling water approaches the wet bulb temperature, so the cooling water outlet temperature can be lowered, which is higher than when used with a normal cooling tower Free cooling is possible up to the wet bulb temperature.

  In order to achieve the above object, the present invention provides a cooling water production facility that includes a plurality of cooling towers that cool the cooling water by exchanging heat between the outside air and the cooling water, and produces the cooling water. A cooling water distribution means for distributing cooling water when water is passed through the tower in series and in parallel; and a water amount setting means for setting the amount of cooling water distributed by the cooling water distribution means. A cooling water production facility is provided.

  In the present invention, it is preferable to include flow rate distribution amount setting means for setting the flow rate distribution amount of the cooling water in series and in parallel, corresponding to the cooling load and the outside wet bulb temperature or the dry bulb temperature.

  According to the present invention, while reducing the pump power by changing the cooling water flow rate, water is passed so that the heat transfer performance of the cooling tower becomes extremely small, even when the cooling water flow rate is small. A heat exchange area between the cooling water and the air can be secured, and a decrease in the cooling capacity of the cooling tower can be prevented.

The block diagram which showed the structure of the cooling water manufacturing equipment of 1st Embodiment The block diagram which showed the structure at the time of parallel operation in the cooling water manufacturing equipment of 2nd Embodiment The block which showed the structure at the time of series operation in the cooling water manufacturing equipment of 2nd Embodiment The block diagram which showed the structure of the cooling water manufacturing equipment of 3rd Embodiment The block diagram which showed the structure of the cooling water manufacturing equipment of 4th Embodiment

  Hereinafter, preferred embodiments of a cooling water production facility according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration of a cooling water production facility 10 according to the first embodiment. The cooling water production facility 10 includes two cooling towers 12 and 14, a cooling water pump (first pump) 18 whose rotational speed is inverter-controlled by a calculator 16, and a load unit 20. The cooling water production facility 10 includes a piping system (first piping system) 22 that distributes the cooling water to the cooling towers 12 and 14 and passes water in parallel, and the cooling water is serially connected to the cooling towers 12 and 14. A piping system (second piping system) 24 for passing water is provided, and the piping system 24 is provided with a cooling water pump (second pump) 26 whose number of revolutions is inverter-controlled by the calculator 16. In addition, a switching valve 28A is provided in the piping system 22, and a switching valve 28B is provided in the piping system 24. The number of cooling towers 12 and 14 is not limited to two, and may be three or more. The cooling water is cooled by exchanging heat with the outside air during free cooling supplied to the cooling towers 12 and 14.

  The cooling water production facility 10 shown in FIG. 1 is configured to be able to stop the operation of the cooling water pumps 18 and 26 when the cooling water flow rate is low. The cooling water production facility 10 can perform serial operation and parallel operation of the cooling towers 12 and 14 by starting and stopping the cooling water pumps 18 and 26. That is, the cooling towers 12 and 14 can be operated in parallel by operating the cooling water pump 18, and the cooling towers 12 and 14 can be operated in series by operating the cooling water pumps 18 and 26. Also, by installing the cooling water pump 26 in the vicinity of the cooling tower 12 and bypassing it, it becomes possible to reduce the head of the cooling water pump 26, and the conveyance power during the bypass is reduced.

  According to this cooling water production facility 10, the cooling water pump 26 is configured so that the cooling towers 12 and 14 are connected in parallel at the time of maximum load, and the piping system 24 is connected in series at a low flow rate of cooling water. ON-OFF.

  FIG. 2 is a block diagram showing the configuration of the cooling water production facility 30 of the second embodiment, and the same or similar members as those in the cooling water production facility 10 shown in FIG. The description is omitted. Moreover, the cooling water production facility 30 in FIG. 2 shows the cooling towers 12 and 14 in parallel operation.

  When the flow rate for processing the maximum load is set to 100% when planning the cooling water production facility 30, when the flow rate is 100%, the flow is switched to the parallel-connected piping system 22 and water is passed to the cooling towers 12 and 14. Do. In this case, the cooling water pump 18 is ON, the cooling water pump 26 is OFF, the switching valve 28A is open, and the switching valve 28B is closed.

  On the other hand, when the cooling water flow rate becomes 50%, that is, when the cooling capacity of the cooling towers 12 and 14 is smaller than the required cooling capacity and the flow rate required for cooling becomes lower, FIG. As shown, the cooling water is passed from the cooling tower 12 to the cooling tower 14 by switching from the parallel-connected piping system 22 to the serially connected piping system 24. In this case, the cooling water pump 18 is ON, the cooling water pump 26 is ON, the switching valve 28A is closed, and the switching valve 28B is open.

  The cooling water flow rate for switching between the serial operation and the parallel operation is set within the cooling water flow rate range of the cooling towers 12 and 14. For example, when the flow rate of the cooling water decreases from 100% to 80% or less, the operation is switched to the series operation shown in FIG. Further, when the cooling water becomes 70% or more from the low flow rate, the operation is switched to the parallel operation shown in FIG.

  The computing unit 16 switches between parallel operation and series operation according to the flow rate of the cooling water, and changes the inverter frequency of the cooling water pump 26 at which the flow rates of the cooling towers 12 and 14 become the same flow rate during the serial operation. As for the flow rate of the cooling water pipe, the relationship between the INV frequency of the cooling water pump 26 and the flow rate is measured in advance, and the INV frequency of the cooling water pump 26 corresponding to the cooling water flow rate of the main pipe is calculated.

  According to this cooling water production equipment 30, the cooling water flow rate of the cooling towers 12 and 14 is controlled to be equal to or higher than the minimum flow rate, and the cooling water in the cooling towers 12 and 14 is obtained by performing a series operation when the flow rate decreases. It is possible to spray water evenly and prevent a decrease in cooling performance by preventing a decrease in heat transfer area.

  When the series operation is performed at a cooling water flow rate of 100%, the power of the cooling water pump 26 is increased as compared with the parallel operation. However, the increase in pump power can be reduced by performing the series operation only at a low flow rate. . Moreover, it becomes possible to expand the cooling water flow rate range that can maintain the heat transfer area, prevent the air volume and increase of the cooling towers 12 and 14, and reduce the power of the fans 12A and 14A installed in the cooling towers 12 and 14. To do.

  FIG. 4 is a block diagram showing the configuration of the cooling water production facility 40 of the third embodiment, and the same or similar members as those of the cooling water production facility 30 shown in FIG. The description is omitted.

  This cooling water production facility 40 has a cooling water production facility 30 as a basic structure, and in this basic structure, a heat exchanger 42 that cools cold water to the load unit 20, an outside air wet bulb temperature detector 44, and a load unit 20 side. A flow meter 46 for measuring the flow rate of the cold water, temperature detectors 48A and 48B for detecting the temperature of the cold water on the load unit 20 side, and a pump 49 are added to the cold water circulation system 47 on the load unit 20 side to produce cold water. Equipment.

  The computing unit 2 of the computing unit 16 consumes energy of the cooling tower fans 12A and 14A, the cooling water pumps 18 and 26, and the cooling water pumps 18 and 26 that are necessary for producing the cooling water corresponding to the cooling load and the outside air wet bulb temperature. The combination of the cooling water outlet temperature, the cooling water outlet temperature, and the cooling tower operation state (series operation, parallel operation) that minimizes the sum of the energy consumption of the devices is calculated using a simulator that calculates the amount. The cooling tower simulator uses the general cooling tower enthalpy standard overall volume transfer coefficient and the cooling tower performance approximation formula to calculate the cooling water outlet temperature from the cooling water inlet temperature, cooling water flow rate, outside air wet bulb temperature, outside air volume. And the fan energy consumption is calculated from the air volume. The energy consumption of the pump calculates the pump head based on the result of predicting or actually measuring the relationship between the pressure loss and the flow rate of the piping system, and calculates the pump power from the relationship between the flow rate and the head.

  The calculating unit 2 instructs the cooling unit temperature control target value, the cooling water production temperature target value, and the optimum value of the operation state of the cooling towers 12 and 14 to the calculating unit 1 and the temperature detector. The INV frequency is changed so that the control target value of the cold water production temperature is reached.

  The computing unit 1 performs INV control of the rotational speeds of the cooling tower fans 12A and 14A so that the cooling water temperature becomes constant according to the cooling water temperature control target value. When the wet bulb temperature and the cooling load are small and can be cooled by one cooling tower 12, the fan 14A of the cooling tower 14 is stopped and the number of operating cooling towers is reduced. This number is stored as table data in a database of the required number of cooling towers obtained by the calculator 16 from the wet bulb temperature and the cooling tower performance with respect to the cooling load. Output. The computing unit 16 changes the operating state and flow rate according to the number of units and the coolant flow rate.

  According to the cooling water production facility 40, the energy consumption amount of the cooling water production facility can be brought close to the minimum value according to the outside air wet bulb temperature and the cooling load. In addition, the cooling towers 12 and 14 can be switched between parallel operation and series operation and the cooling water variable flow rate can be changed so that the energy consumption is reduced.

  Also, during free cooling operation of cooling water, if the load is large, the cooling tower can be operated in parallel to increase the heat transfer area and improve the cooling performance, and the cooling water temperature can be brought close to the wet bulb temperature, Free cooling can be extended. In addition, when the load is small, it is possible to maintain the minimum flow rate necessary for heat transfer of the heat exchanger and reduce the flow rate, thereby reducing useless power.

  FIG. 5 is a block diagram showing the configuration of the cooling water production facility 50 of the fourth embodiment, and the same or similar members as those in the cooling water production facility 40 shown in FIG. The description is omitted.

  In the cooling water production facility 50, the heat exchanger 42 (see FIG. 4) is used as the condenser 54 of the refrigerator 52. In addition, the control unit 16 calculates a control target value of the cooling water flow rate at which the total power of the refrigerator 52, the cooling water pumps 18 and 26, the cooling towers 12 and 14, and the cooling water pumps 18 and 26 becomes the minimum. Based on the control target value of the water flow rate, the cooling towers 12 and 14 are configured to be switched between parallel operation and series operation, and the INV frequency of the cooling water pumps 18 and 26 is switched.

  In this cooling water production facility 50, since the cooling towers 12 and 14 used for the cooling water of the condenser 54 of the refrigerator 52 increase the heat transfer area, the cooling water approaches the wet bulb temperature. By lowering the temperature, the refrigerator 52 can reduce the cooling water temperature and increase the coefficient of performance, thereby reducing energy consumption.

  In addition, by controlling the fans 12A and 14A of the cooling towers 12 and 14 so that the cooling water outlet temperature setting value is constant, temperature control without using INV is possible, and temperature stability is Although lower, the system can be simplified.

  In addition, the flow meter on the load unit 20 side may calculate the flow rate from the measured value of the differential pressure using the relationship between the flow rate of the cold water flowing through the heat exchanger 42 and the differential pressure of the cold water. Thereby, a flow meter can be reduced.

  Furthermore, when the cold water production temperature is prioritized, the outdoor wet bulb temperature is high, and the series operation can satisfy the cold water production temperature control target value rather than the parallel operation, the operation may be switched to the series operation. Thereby, when the load part 20 and an external air wet bulb temperature become high and cold water production temperature cannot be satisfied by parallel free cooling, it becomes possible to perform free cooling by series operation. Therefore, free cooling operation with less energy consumption than when cold water is produced by the refrigerator 52 is possible, and the annual free cooling operation period can be extended.

  DESCRIPTION OF SYMBOLS 10, 30, 40, 50 ... Cooling water production equipment, 12, 14 cooling tower, 12A, 14A ... Fan, 16 ... Calculator, 18 ... Cooling water pump, 20 ... Load part, 22 ... Piping system which passes water in parallel , 24 ... Piping system for passing cooling water in series, 26 ... Cooling water pump, 28A, 28B ... Switching valve, 42 ... Heat exchanger, 44 ... Outside wet bulb temperature detector, 46 ... Flow meter, 47 ... Cooling Water circulation system, 48A, 48B ... Temperature detector, 52 ... Refrigerator, 54 ... Condenser

Claims (5)

A plurality of cooling towers for cooling the cooling water by exchanging heat between the cooling water and outside air;
A first pump for circulating cooling water cooled by the plurality of cooling towers between the plurality of cooling towers and a load section;
A first piping system that distributes the cooling water that has passed through the load section to the plurality of cooling towers and passes water in parallel;
A second piping system for passing cooling water in series through the plurality of cooling towers;
A second pump for passing cooling water through the second piping system;
A cooling water production facility comprising:   A function of changing the rotational speeds of the first pump and the second pump, and a computing unit, wherein the first pump is operated in accordance with a command from the computing unit, and a plurality of cooling towers are passed in parallel. The cooling water production facility according to claim 1, wherein an operation for performing the operation and an operation for operating the first pump and the second pump to pass water through the cooling tower in series are performed. Having cooling load measuring means,
The computing unit uses the cooling load measured by the cooling load measuring means and the wet bulb temperature measurement value as input conditions, and energy consumption amounts of the plurality of cooling towers, the first pump, and the second pump are calculated. Calculate the cooling water flow rate, the cooling water temperature, and the cooling tower operation state so as to be minimized, start and stop the first pump and the second pump, and switch between the serial operation and parallel operation of the cooling tower, The cooling water manufacturing facility according to claim 2, wherein the number of revolutions of the first pump and the second pump is controlled. In a cooling water production facility that produces cooling water with a plurality of cooling towers that cool the cooling water by exchanging heat between the outside air and the cooling water,
A cooling water distribution means for distributing cooling water when the plurality of cooling towers pass in series and in parallel when passing water;
A cooling water production facility comprising: a water amount setting means for setting the amount of cooling water distributed by the cooling water distribution means.   The cooling water production facility according to claim 4, further comprising a flow rate distribution amount setting means for setting the flow rate distribution amount of the cooling water in series and in parallel with the cooling load and the outside air wet bulb temperature or the dry bulb temperature.

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