Chilled water heat source system and method for controlling the chilled water heat source

Abstract

To provide a cold water heat source system and a control method capable of efficiently supplying cold.SOLUTION: A cold water heat source system includes: an ice water tank 16 for storing cold water supplied from a cold source 12 via primary outgoing piping 37; a secondary pump 22 for supplying cold water from the ice water tank 16 via secondary outgoing piping 19 to a load in accordance with demand from the load; a water tank 18 for storing water returned from the load via secondary return piping 23; a primary pump 13 sending water from the water tank 18 via primary return piping 36 to the cold source 12; a water gauge PE1 for detecting a water level in the ice water tank 16; and a control device 14 that reduces water feeding amount of the primary pump 13 when the water level detected by the water gauge PE1 increases, and increases the water feeding amount of the primary pump 13 when the water level lowers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a large-scale chilled water heat source system that cools while transporting chilled water used for cooling various purposes, such as production in food factories, and a method for controlling the chilled water heat source. [Background technology]

[0002] For example, when it comes to chilled water heat sources used for cooling chilled water for air conditioning, which is in high demand even in factories, sealed chilled water heat sources are often chosen because there is little opportunity for the chilled water to come into contact with outside air containing dust and microorganisms in the piping system through which the chilled water is transported, which reduces corrosion and provides hygienic advantages.

[0003] In factories, even in production cooling water systems, the temperature field for the chilled water supply and return temperatures for air conditioning purposes is different for production cooling water, so a set of sealed chilled water heat sources is often installed as a system separate from the chilled water heat source that cools the chilled water.

[0004] Patent Document 1 discloses a technology for controlling the flow rate of a variable flow pump that sends chilled water from the supply header to the load and a variable flow pump that sends chilled water from the return header to the chiller, based on the detection value of a flow meter installed in a balance pipe between the supply header and the return header, in an air conditioning system that uses a sealed piping system with the primary side as a heat source and the secondary side as a load via a supply header and a return header.

[0005] In air conditioning systems using a closed-system chilled water heat source like the one described in Patent Document 1, the amount of heat processed is adjusted by controlling the chilled water flow rate of the cooling medium according to the heat load using a two-way valve on the load side of the air conditioner or other device, and the capacity of refrigerators and other devices is controlled according to this flow rate, allowing for continuous operation. In this way, even if the load fluctuates, as long as the temperature field can be controlled and the load fluctuations are within a certain range, the chilled water flow rate can be adjusted while the capacity of the chilled heat source can be adequately controlled. However, in systems that include multiple systems with different supply and return temperature fields and where the heat usage on the load side suddenly increases or decreases, a chilled water heat source combined with air conditioning applications cannot cope.

[0006] Patent Document 2 discloses an operation control method for heat source equipment, which measures the water level in a heat storage tank (ice heat storage tank), and when the water level reaches a predetermined value, determines that heat storage is complete and ends the heat storage operation, thereby estimating the amount of heat storage, while measuring the cold water return temperature and cold water circulation flow rate, and operates the heat source equipment when these measured values ​​are above a set value, and stops the heat source equipment when they are below the set value.

[0007] The heat source equipment of this heat source equipment control method cools brine, and during nighttime heat storage operation, the outlet temperature is set to 0°C and the brine is sent out from the heat source equipment, passing through the tubes of the ice-making heat exchanger of the ice thermal storage tank, freezing the water in the ice thermal storage tank on the fins of the ice-making heat exchanger and storing the ice, and during daytime cooling operation, the brine outlet temperature is set to 3°C and the brine-water heat exchanger cools the cold water so that it does not freeze. The cold water is an open system in the ice thermal storage tank and circulates through sprinkler piping to melt the ice in the water tank. Here, the water level is measured in the ice storage tank, but as for the amount of ice stored at night, since all loads other than the ice storage tank are in the form of sealed piping and there is little thermal load fluctuation and little change in flow rate at night, even when cold water is circulated by a pump, the change in water level is equal to the change in volume due to the amount of phase change from water to ice, and this is used to determine the amount of ice stored; if a sudden load request causes an increase or decrease in the amount of pumping on the secondary side to affect the water level change, the amount of ice stored cannot be read from the water level, so load fluctuations are not determined from this water level.

[0008] On the other hand, Patent Document 3 proposes a control method for an ice thermal storage control system incorporating an ice-making coil, in which the control means for controlling the brine circulation pump and heat source unit operates at a capacity that results in the highest operating efficiency within the range of low-capacity operation of the heat source when ice-making operation begins, compares the actual water level with a set target water level every predetermined time, and increases the initial most efficient capacity by a predetermined amount if the actual water level falls below the target water level, and operates at the initial most efficient capacity if the actual water level exceeds the target water level. This technology incorporates the ice-making coil and ice thermal storage tank into the heat source system, exchanges heat between the brine and water separated from the cold water circulation system, which is simply a thermal storage body, in the ice-making coil, and monitors the heat storage level of the separated, stagnant water, but the cold water circulation system is merely a closed system.

[0009] Patent Document 4 discloses an ice thermal storage control method having an ice thermal storage tank with a built-in ice-making coil, in which a control means for controlling a brine circulation pump and a heat source machine adjusts the flow rate of brine based on the measurement value of a water level sensor in the ice thermal storage tank, reducing the flow rate of brine when the measured water level by the water level sensor is lower than a target water level, and increasing the flow rate of brine when the measured water level by the water level sensor is higher than the target water level. This technology also incorporates the ice-making coil and ice thermal storage tank into the heat source machine system, exchanges heat between the brine and water separated from the cold water circulation system, which is simply a heat storage body, in the ice-making coil, and monitors the heat storage level of the separated, stagnant water by the water level, and the cold water circulation system is merely a closed system.

[0010] Patent Document 5 discloses a technology that includes a heat source unit that generates cold and hot water, a heat storage tank, a circulation indoor unit that circulates the cold and hot water to perform air conditioning, a heat storage utilization indoor unit that performs air conditioning using the cold and hot water stored in the heat storage tank, and a control unit, where the cold and hot water stored in the heat storage tank, which is an open system, is water that can be freely drained and can be stored from zero to full, containing cold or hot water that has not been used in the circulation indoor unit, and the heat storage utilization indoor unit determines the amount of cold and hot water stored in the heat storage tank (flow rate detection), and opens and closes a valve between the heat storage tank based on the determined storage amount, so that the cold and hot water that has been used for heat in one pass is drained without being circulated. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 2899437 [Patent Document 2] Japanese Patent Application Publication No. 7-133944 [Patent Document 3] Patent No. 5464947 [Patent Document 4] Patent No. 5686532 [Patent Document 5] Patent No. 6250195 Summary of the Invention [Problem to be solved by the invention]

[0012] In food factories and other facilities, large-scale heat sources are used to cool food ingredients in addition to indoor air conditioning, and the flow rate of chilled water used for heat transfer is extremely high. Furthermore, chilled water is circulated through multiple systems, and some systems may require a large amount of cold heat at once, resulting in an imbalance between the amount of chilled water required by the load and the amount of chilled water that can be supplied to the load. For this reason, systems such as those described in Patent Documents 1 to 5, in which high-temperature chilled water returning from the load is heat-exchanged with a chlorofluorocarbon refrigerant or brine cooled in the refrigeration cycle of the chilled heat source in a heat exchanger and then sent directly to the load, are insufficient.

[0013] In addition, the supply and return chilled water piping is also complex, and there may be a temporary difference between the amount of chilled water sent to the load and the amount of chilled water returning from the load. In such cases, simply providing a balance pipe between the supply header and return header as in Patent Document 1 is not enough to achieve a sufficient balance between supply and return.

[0014] The present invention has as its technical object the provision of a chilled water heat source system and a method for controlling a chilled water heat source that can efficiently supply chilled heat even to a large-scale, complex load. [Means for solving the problem]

[0015] The chilled water heat source system 10 of the present invention comprises an iced water tank 16 that stores chilled water supplied from a chilled heat source 12 via a primary forward piping 37, a secondary pump 22 that supplies chilled water from the iced water tank 16 to a load via a secondary forward piping 19 in response to demand from the load, a water tank 18 that stores water returning from the load via a secondary return piping 23, a primary pump 13 that sends water from the water tank 18 to the chilled heat source 12 via a primary return piping 36, a water level meter PE1 that detects the water level of the iced water tank 16, and a control device 14 that reduces the water supply rate of the primary pump 13 when the water level detected by the water level meter PE1 increases and increases the water supply rate of the primary pump 13 when the water level detected by the water level meter PE1 decreases.

[0016] In such a chilled water heat source system 10, it is preferable that the rotation speed of the primary pump 13 is controlled by an inverter, and that the control device 14 proportionally controls the water supply amount of the primary pump 13 by setting a proportional band within a predetermined range in accordance with the increase or decrease in the water level in the ice water tank 16.

[0017] In addition, in such a chilled water heat source system 10, the control device 14 can turn on the operation of the chilled heat source 12 when the water level in the ice water tank 16 drops to a first set water level, and turn off the operation of the chilled heat source 12 when the water level in the ice water tank 16 rises to a second set water level.

[0018] In addition, in such a chilled water heat source system 10, it is preferable to position a feed header 15 on the outlet side of the secondary pump 22 of the secondary feed piping 19, branch off from the feed header 15 to supply chilled water to each system of the chilled water load, and position a return header 17 on the load side of the water tank 18 of the secondary return piping 23, so that the return chilled water from the chilled water load of each system is joined in the return header 17.

[0019] In addition, in such a chilled water heat source system 10, the secondary forward piping 19 between the ice water tank 16 and the secondary pump 22 and the secondary return piping 23 between the return header 17 and the water tank 18 are connected by a balancing piping 24 with a bypass pump 25 installed in between, and it is preferable that the control device 14 performs bypass operation on the primary side through the balancing piping 24 as an operation to reduce the chilled water temperature in the ice water tank 16 after a long-term shutdown.

[0020] The method for controlling a chilled water heat source of the present invention is characterized by storing chilled water supplied from the chilled heat source 12 via the primary feed pipe 37 in the iced water tank 16, supplying chilled water from the iced water tank 16 to the load via the secondary feed pipe 19 by the secondary pump 22 in response to demand from the load, and storing water returning from the load via the secondary return pipe 23 in the water tank 18, detecting the water level in the iced water tank 16, and reducing the water supply rate of the primary pump 13 that sends water from the water tank 18 to the chilled heat source 12 via the primary return pipe 36 when the water level increases, and increasing the water supply rate of the primary pump 13 when the water level decreases.

[0021] In such a method for controlling a chilled water heat source, it is preferable to proportionally control the amount of water delivered by the primary pump 13 in accordance with a proportional band set within a predetermined range in response to an increase or decrease in the water level in the ice water tank 16.

[0022] In such a method for controlling a cold water heat source, when the water level in the ice water tank 16 falls to a first set water level, the operation of the cold heat source 12 can be turned ON, and when the water level in the ice water tank 16 rises to a second set water level, the operation of the cold heat source 12 can be turned OFF.

[0023] In such a method of controlling a chilled water heat source, it is preferable to branch off pipes from the feed header 15 located on the outlet side of the secondary pump 22 of the secondary feed pipe 19 to supply chilled water to each system of the chilled water load, and then combine the return chilled water from the chilled water load of each system in the return header 17 located on the load side of the water tank 18 of the secondary return pipe 23, and transport the chilled water using the secondary pump 22.

[0024] In such a method for controlling a chilled water heat source, the secondary supply pipe 19 between the ice water tank 16 and the secondary pump 22 and the secondary return pipe 23 between the return header 17 and the water tank 18 are connected by a balancing pipe 24 with a bypass pump 25 installed in between, and it is preferable that the control device performs primary side bypass operation through the balancing pipe 24 as an operation to reduce the chilled water temperature in the ice water tank 16 after a long-term shutdown. [Effects of the Invention]

[0025] The chilled water heat source system of the present invention stores chilled water supplied from the chilled heat source in an ice water tank and water returned from the load in a water tank, thereby alleviating the temporary imbalance between the load demand and the supply from the chilled water heat source, which is likely to occur in large-scale systems. In other words, since the load side often operates with sudden load fluctuations similar to batch operation, the water level in the ice water tank often drops during peak periods and recovers when the load side operation is stopped. With this invention, when the water level drops, the amount of chilled water produced can be increased to meet increased demand, and when the water level rises, the amount of chilled water produced can be reduced, contributing to energy conservation. This allows for efficient supply of chilled water to even large-scale, complex loads.

[0026] In such a chilled water heat source system, if the rotation speed of the primary pump is controlled by an inverter and the control device sets a proportional band within a predetermined range and increases or decreases the flow rate of the primary pump by proportional control in accordance with the increase or decrease in the water level in the ice water tank, it is possible to respond more quickly and smoothly to increases or decreases in the load.

[0027] The control device turns on the cold heat source when the water level in the ice water tank drops to a first set water level, and turns off the cold heat source when the water level in the ice water tank rises to a second set water level. This is because all that is required is to switch the cold heat source on and off, making the control simple and the control device also simple.

[0028] In the above-mentioned chilled water heat source system, if a feed header is located on the secondary pump outlet side of the secondary feed piping, and the chilled water is branched off from the feed header and supplied to each system of chilled water loads, and a return header is located on the load side of the water tank of the secondary return piping, and the return chilled water from the chilled water loads of each system is merged in the return header, the effects of pressure fluctuations can be reduced and chilled water can be distributed smoothly to a large number of loads.

[0029] The chilled water heat source control method of the present invention can efficiently supply chilled heat even to large-scale, complex loads. In this chilled water heat source control method, if the flow rate of the primary pump is increased or decreased by proportional control within a predetermined proportional band in accordance with the increase or decrease in the water level of the ice water tank, the increase or decrease in the load can be quickly and smoothly responded to.

[0030] In the control method for the cold water heat source, when the water level in the ice water tank falls to a first set water level, the operation of the cold heat source is turned ON, and when the water level in the ice water tank rises to a second set water level, the operation of the cold heat source 12 is turned OFF. This is because it is only necessary to switch the cold heat source ON / OFF, making the control method simple and the control device simple as well.

[0031] In addition, if pipes are branched from the forward header located on the secondary pump outlet side of the secondary forward pipe to supply each system of cold water loads, and the return cold water from the cold water loads of each system is merged in the return header located on the load side of the water tank of the secondary return pipe, and the cold water is transported by the secondary pump, the effects of pressure fluctuations can be reduced and cold energy can be distributed smoothly to a large number of loads.

[0032] Furthermore, if the secondary supply piping between the ice water tank and the secondary pump and the secondary return piping between the return header and the water tank are connected by balancing piping with a bypass pump installed in between, even if the temperature of the chilled water in the ice water tank rises after a long-term shutdown and approaches the temperature of the chilled water in the water tank, the chilled water temperature reduction operation as a preparatory operation after a long-term shutdown can be performed through the balancing piping as a primary side bypass, thereby lowering the temperature of the chilled water to be cooled to each load and allowing cold energy to be supplied immediately. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is an instrumentation flow diagram showing an embodiment of a chilled water heat source system of the present invention. [Figure 2] FIG. 2 is an instrumentation flow diagram showing an example of a cold heat source of a chilled water heat source system. [Figure 3] 10 is a graph illustrating one embodiment of a method for controlling a primary pump. [Figure 4] FIG. 10 is an instrumentation flow diagram showing another example of a water tank used for cooling and heat removal. DETAILED DESCRIPTION OF THE INVENTION

[0034] The chilled water heat source system 10 shown in Figure 1 comprises a chilled water supply unit 11 that supplies chilled water to loads and receives water returned from the loads, a chilled heat source 12, a primary pump 13 that sends water from the chilled water supply unit 11 to the chilled heat source 12 via primary return piping 36, and a control device 14. The chilled water supply unit 11 has a supply header 15 that branches the pipes to the loads, an iced water tank 16 connected to the supply header 15, a return header 17 that collectively receives water returned from each load, and a water tank 18 connected to the return header 17.

[0035] A flow meter 20 is installed in the piping 19 that supplies chilled water from the ice-water tank 16 to each load via the supply header 15. A secondary pump 22 is installed in the piping 21, which is part of the piping 19 that supplies chilled water to the supply header 15. Multiple secondary pumps 22 (four in the figure) are installed to control the number of units. The ice-water tank 16 is equipped with a thermometer TEW1 and a water level gauge PE1. The thermometer TEW1 detects the temperature to determine whether the chilled water supplied to the ice-water tank 16 is at the appropriate temperature. The water level gauge PE1 detects whether the water level in the ice-water tank 16 is within the appropriate range and detects an excess or deficiency in the primary supply of chilled water, which occurs due to the difference between the amount of chilled water drawn by the secondary pump on the secondary side to the load and the amount of chilled water delivered to the ice-water tank 16 by the primary pump, which cools and delivers the chilled water. The water level gauge PE1 preferably detects water pressure and converts it into a water level. While other types of water level gauges are acceptable, one that can continuously detect the water level is preferred.

[0036] The water tank 18 may also be provided with a thermometer TEW2 and a water level gauge PE2. These are used to confirm that the temperature and level of the return water are within appropriate ranges. Note that while the balance between the supply of cold water to the load and the return of water from the load can be estimated using the value detected by the water level gauge PE2 of the water tank 18, it can be detected more quickly based on the water level in the ice water tank 16.

[0037] It is preferable to position the supply header 15 on the outlet side of the secondary pump 21 of the secondary supply piping 19 from the ice water tank 16, branch off from the supply header 15 to supply to each system of chilled water loads, and position the return header 17 on the load side of the water tank 18 of the secondary return piping 23, so that the returning chilled water from the chilled water loads of each system joins in the return header 17. This eliminates the effects of pressure deviation fluctuations in the secondary supply piping 19, which is branched and sent out due to pressure changes caused by the water level when branched from the ice water tank 16, where the water level fluctuates, and pressure fluctuations due to changes in the water tank 18 and pressure fluctuations in the secondary return piping 23 when the returning secondary return piping 23 is directly connected to the water tank 18.

[0038] A balancing pipe 24 is provided between the pipe 19a for cold water, which is the suction side of the secondary pump 22 that discharges from the ice water tank 16, and the outlet between the return header 17 and the water tank 18 of the pipe 23 for water that enters the water tank 18, and a bypass pump 25 and a stop valve 26 are interposed in this pipe 24. These pipes are used when starting up the system after a long shutdown, for example, to cool the water in the water tank 18 with a refrigerator 30 and return it to the ice water tank 16, thereby pre-cooling the water temperature in the ice water tank 16, which has risen in temperature, without sending it to the load side, and thereby ensuring an appropriate temperature for the water sent to the secondary side.

[0039] The cold heat source 12 includes a refrigerator 30 that incorporates a compressor, a condenser, and an evaporator and cools water from a water tank 18 using a refrigeration cycle, a cooler 31 that cools high-temperature cooling water that has exchanged heat with the refrigerant in the refrigerator 30, and a cooling water pump 32 that sends the cooled cooling water from the cooler 31 to the refrigerator 30. In this embodiment, the refrigerator 30 includes a plurality of unit refrigerators 33 arranged in parallel, and each unit refrigerator 33 is connected to the primary pump 13 through a branching header 34 and a primary return pipe 36. The cold water coming out of each unit refrigerator 33 is combined in a confluence header 35 and supplied to the ice water tank 16 through a primary supply pipe 37.

[0040] In the case of Figure 1, multiple individual chillers 33 are connected in parallel via branching headers 34 and merging headers 35. However, if there is a large temperature difference between the supply and return temperatures of chilled water, they can also be connected in series. A parallel connection can increase the flow rate of chilled water to be cooled, while a series connection can lower the supply temperature of chilled water to be cooled. Depending on the required specifications, the chiller 30 equipped with four individual chillers 33 can be further connected in parallel, in series, or in a combination of these (see Figure 4).

[0041] The cooler 31 used to cool the cooling water coming out of the chiller 30 may be, for example, a sprinkler cooler (cooling tower) 40, as shown in Figure 2, which uses the heat of vaporization of water to cool the cooling water with outside air. When using a sprinkler cooler 40, water sprayed from a sprinkler 41 is cooled by blowing outside air drawn in by a fan 42. This method uses natural energy, making it energy-saving and environmentally friendly. The cooling water cooled by the sprinkler cooler 40 in Figure 2 is returned to the chiller 30 by three pumps 43, the number of which is controlled. Reference numeral 44 denotes a control panel that controls an anti-freeze heater 45 based on the water temperature detected by a thermometer TEW3. Heating is forcibly stopped when the water level detected by a water level gauge PE3 falls below a predetermined level. Reference numeral 46 denotes a chemical injection device that maintains a constant chemical concentration in the cooling water.

[0042] The chiller 30 may be a compression chiller having the refrigeration cycle described above, or a low-temperature water absorption chiller that uses an absorption liquid regenerated by a high-temperature heat source for cooling instead of an electrically operated compressor. The low-temperature water absorption chillers may also be connected in parallel at positions N1 and N2 in Fig. 1. It is also possible to operate the chiller at night when electricity is cheap to make ice in the heat storage tank, and use an ice thermal storage tank that uses the ice in the thermal storage tank to cool water during the day.

[0043] The primary pump 13, located midway along the primary outgoing piping 36 of the chilled water heat source system 10 in Figure 1, consists of three pumps CP1, CP2, and CP3 connected in parallel. One of these (CP3) is a spare, and is used when the two normally used pumps CP1 and CP2 are inspected or break down. All of these pumps CP1 to CP3 are inverter-controlled pumps that control the rotation speed of the drive motor using a frequency changed by an inverter. However, pumps with other control methods can also be used.

[0044] When the water level in the ice water tank 16 drops, the control device 14 increases the frequency of the drive power to increase the rotation speed of the primary pump 13, i.e., pumps CP1 to CP3, and when the water level rises, it decreases the frequency to suppress the rotation speed of pumps CP1 to CP3. This achieves energy conservation while ensuring the required amount of water. The control device 14 is a computer that includes, for example, a memory for storing the control program and the relationship between water level and frequency (graph, function), a data acquisition unit for inputting the current measurement value of the water level gauge, and a calculation unit for calculating the frequency from the acquired water level.

[0045] The control device 14 sets the water level in the ice water tank 16 as a first set water level, which is a predetermined amount less than the water level balanced with the water tank 18, and a second set water level, which is a predetermined amount more than the water level balanced with the water tank 18. When the water level falls to the first set water level, the control device 14 turns on the operation of the cold heat source 12, and when the water level rises to the second set water level, the control device 14 turns off the operation of the cold heat source 12. It is also preferable to have another calculation unit. In this way, simply by monitoring large increases or decreases in the water level, increases in the secondary load can be clearly detected, and by using this information to start and stop the cold heat source 12, it is possible to operate it at the appropriate time while also achieving energy-saving operation.

[0046] In addition to the above, the control device 14 may have a function to issue a predetermined warning or stop operation when the current water temperature acquired from a thermometer that measures the water temperature in each pipeline section deviates from an appropriate range. Also, when the current flow rate or water level acquired from a flow meter or water level meter that measures the flow rate in each pipeline section deviates from an appropriate range, the control device 14 may issue a predetermined warning or stop operation.

[0047] The relationship between water level and frequency is, for example, as shown in the graph in Figure 3, where as the water level (horizontal axis) rises, the frequency (vertical axis) decreases linearly. This can also be interpreted as a proportional relationship with a negative coefficient. In this case, upper and lower frequency limits are set, and the frequency is varied linearly between them. In the field of instrumentation, this proportional variation between the upper and lower frequency limits, connected by a straight line, is expressed as a proportional band between the upper and lower limits, and proportional control is performed between these limits. This proportional band, which is a function relating water level and frequency, is input into the control device 14 in advance.

[0048] By using a proportional band that linearly increases or decreases the water level and frequency for proportional control, it becomes easier to calculate as PID control, which further uses integral time and derivative time. The water level is the amount of water held in the tank, and is also the amount obtained by integrating the flow rate over time. Therefore, if there is sufficient margin in the water level, it can easily respond to sudden increases or decreases in the flow rate required by the load.

[0049] Although the preferred embodiments of the chilled water heat source system of the present invention have been described above, the present invention is not limited to these embodiments and other embodiments can be adopted. In Fig. 1, the ice water tank 16 and the water tank 18 are shown with marks of general tanks using a cylindrical body and a spherical head, but they can also be cylindrical or rectangular tanks in order to make the relationship between the water level and the amount of water stored proportional. [Explanation of symbols]

[0050] 10 Chilled water heat source system 11 Cold water supply 12 Cold source 13 Primary pump 14 Control Unit 15 Outbound Header 16 Ice Water Tank 17 Return Header 18 Water Tank 19 Secondary forwarding piping 20 Flow meter 21 Piping for supplying cold water to the outgoing header 22 Secondary Pump TEW1, TEW2 thermometer PE1, PE2 Water level gauge 23 Secondary return piping 24 Balancing piping 25 Bypass pump 26 Stop valve 30 Refrigeration Machine 31 Cooler 32 Cooling water pump 33 Single Refrigerator 34 Header for water entering the chiller 35 Header for chilled water coming out of the refrigerator 36 Primary return piping 37 Primary Outgoing Piping 40 Sprinkler Cooler 41 Sprinkler 42 Fans 43 Pump that sends cooling water from the water cooler 44 Control Panel 45 Heater TEW1, TEW2, TEW3 Thermometer PE1, PE2, PE3 Water level gauge N1, N2 connection position CP1, CP2, CP3 pumps (primary pumps) 46 Chemical dosing device

Claims

1. an ice water tank for storing cold water supplied from a cold source through a primary forward piping; a secondary pump that supplies chilled water from the ice water tank to the load through a secondary supply pipe in response to demand from the load; a water tank for storing water returning from the load through a secondary return pipe; a primary pump that sends water from the water tank to the cold heat source through a primary return pipe; a water level meter for detecting the water level of the ice water tank; a control device for reducing the amount of water supplied by the primary pump when the water level detected by the water level meter increases, thereby reducing the amount of chilled water produced, and for increasing the amount of water supplied by the primary pump when the water level decreases; A chilled water heat source system.

2. 2. The chilled water heat source system of claim 1, wherein the rotation speed of the primary pump is controlled by an inverter, and the control device proportionally controls the water supply rate of the primary pump by setting a proportional band within a predetermined range in response to an increase or decrease in the water level in the ice water tank.

3. The chilled water heat source system of claim 1 or claim 2, characterized in that the control device turns on the operation of the cold heat source when the water level in the ice water tank decreases to a first set water level, and turns off the operation of the cold heat source when the water level in the ice water tank increases to a second set water level.

4. A chilled water heat source system as described in any one of claims 1 to 3, characterized in that a feed header is located on the secondary pump outlet side of the secondary feed piping, and the chilled water is branched off and supplied to each system of the chilled water load from the feed header, and a return header is located on the load side of the water tank of the secondary return piping, and the return chilled water from the chilled water load of each system is merged in the return header.

5. A secondary forward piping between the ice water tank and the secondary pump and a secondary return piping between the return header and the water tank are connected by a balancing piping with a bypass pump installed therebetween, 5. The chilled water heat source system according to claim 4, wherein the control device controls the system to perform primary side bypass operation through a balancing pipe as an operation for lowering the temperature of chilled water in the ice water tank after a long-term shutdown.

6. The cold water supplied from the cold source through the primary supply pipe is stored in the ice water tank. According to the demand from the load, a secondary pump supplies chilled water to the load from the ice water tank through the secondary supply pipe. The water returning from the load through the secondary return pipe is stored in the water tank, Detects the water level in the ice water tank, When the water level increases, the amount of water sent by the primary pump, which sends water from the water tank to the cold heat source via the primary return pipe, is reduced to decrease the amount of chilled water produced, and when the water level decreases, the amount of water sent by the primary pump is increased to increase the amount of chilled water produced. Methods for controlling chilled water heat sources.

7. 7. The method for controlling a chilled water heat source according to claim 6, wherein the amount of water delivered by the primary pump is proportionally controlled by setting a proportional band within a predetermined range in response to an increase or decrease in the water level in the ice water tank.

8. 8. The method for controlling a chilled water heat source according to claim 6 or claim 7, characterized in that when the water level in the ice water tank falls to a first set water level, the operation of the chilled heat source is turned on, and when the water level in the ice water tank rises to a second set water level, the operation of the chilled heat source is turned off.

9. A method for controlling a chilled water heat source described in any one of claims 6 to 8, characterized in that piping is branched from a feed header located on the secondary pump outlet side of the secondary feed piping to supply chilled water to each system of the chilled water load, and the return chilled water from the chilled water load of each system is merged in a return header located on the load side of the water tank of the secondary return piping, and the chilled water is transported by a secondary pump.

10. 10. The method for controlling a chilled water heat source according to claim 9, wherein a secondary supply pipe between the ice water tank and the secondary pump and a secondary return pipe between the return header and the water tank are connected by a balancing pipe with a bypass pump installed in between, and the control device controls the operation to perform primary side bypass operation through the balancing pipe as an operation to reduce the chilled water temperature in the ice water tank after a long-term shutdown.

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