JP2009168369A - Ice bank system and operation control method for ice bank system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably perform operation control of the stop and start of ice storage by accurately detecting the stored state of ice in an ice thermal storage tank in a dynamic ice bank system. <P>SOLUTION: Ice-water slurry manufactured by a supercooler 11 is supplied into the ice thermal storage tank 1 and ice P is stored in the tank. A cooling load 23 is supplied with cold water taken from the ice thermal storage tank 1 by a second water intake pipe 21. A full stored state in the ice thermal storage tank 1 is detected by the rising height of the ice P measured by an ultrasonic height meter 31, and based on such constitution, the start and stop of the ice storage operation are controlled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides an ice bank system for maintaining a chilled cold water temperature at a predetermined temperature and operating the system efficiently in an ice bank system (ice storage system) for storing so-called sherbet-like ice in a food factory, for example. And an operation control method thereof.

  In food factories and dairy products-related factories, so-called chilled cold water, for example, low-temperature cold water of 0 ° C. to 1.5 ° C., for example, is used, so-called ice bank for producing and supplying such low-temperature cold water Conventionally, an externally fused static ice bank has been adopted as a system. The static type ice bank has a good so-called “ice glutinousness (sustainability of ice phase)”, and even from the viewpoint of the history of freezing and refrigeration, it was easily accepted by food factories. However, the good thing about “Ichi no Mochi” is that it means “poor de-icing properties”, so much effort and know-how have been put into the temperature control of chilled cold water.

  On the other hand, among the above-described static type ice banks, among the dynamic type ice banks having “good de-icing characteristics”, those utilizing the supercooling phenomenon of water are promising for the food industry. However, the temperature control method for chilled cold water by this dynamic ice bank has not been established yet.

  The temperature control of chilled chilled water in the ice bank system requires detection of the full storage state and operation control of ice storage stop and ice storage start (restart) as preconditions. There is a so-called load prediction technique, and setting of a target heat storage amount according to the outside air temperature during the day as disclosed in Japanese Patent Laid-Open No. 2002-277018 “Air Conditioner” (Patent Document 1), The setting of the target heat storage amount by the use heat load amount of the air conditioner on the previous day disclosed in (Patent Document 2) is exemplified.

  However, an error is naturally included in the load prediction and the calculation of the manufacturing cold heat amount, and the target heat storage amount may include a large error. In particular, excessive ice storage in a conventional static type ice bank is caused by bridging pointed out in Japanese Patent Laid-Open No. 11-287541 “Ice Thermal Storage Device and Operation Control Method of Ice Thermal Storage Device” (Patent Document 3), 128642 “Water-cooled thermal storage beverage device” (Patent Document 4) leads to the problem of coil freezing (deformation / destruction). Therefore, it is necessary to detect the full storage state in the ice bank system separately from the calculation. There is.

  In this regard, for example, the amount of ice by the water level sensor in Japanese Patent Application Laid-Open No. 2005-114338 “Full Ice Detection Device and Detection Method” (Patent Document 5) and Japanese Patent Application Laid-Open No. 9-72582 “Heat Storage Chilled Water Device” (Patent Document 6). An ice bank detection means for detecting the amount of ice formation in Japanese Patent Application Laid-Open No. 8-287345 “Cooling Control Device for Vending Machine” (Patent Document 7) can be cited as a prior art related to this.

JP 2002-277018 A JP-A-6-74499 Japanese Patent Laid-Open No. 11-287541 JP-A-9-128642 JP 2005-114338 A JP-A-9-72582 JP-A-8-287345

  However, the ice amount detection technologies described in Patent Documents 5 to 7 are all used for static ice banks, and as they are, dynamic ice bank systems that manufacture and store sherbet-like ice. Not applicable to In other words, since ice is always submerged in static ice storage tanks, as the IPF increases (the amount of stored ice increases), the water level in the ice storage tank rises due to the density difference between ice and water. To do. By utilizing this fact, in the static type, the water level sensor detects the ratio of water and ice, that is, IPF. However, in a dynamic-type ice storage tank, a sherbet-like ice layer is stored not only below the water surface but also above the water surface. The sherbet-like ice layer below the surface of the water is a mixture of “snow-like ice” and “water”, and the sherbet-like ice layer above the surface of the water is a mixture of “snow-like ice” and “air”. ing. Since the ratio of these “ice”, “water”, and “air” is unknown, it is impossible to detect the IPF by the value of the water level sensor as in the static type.

  The present invention has been made in view of the above points, and provides a system for accurately detecting the ice storage state of ice in an ice heat storage tank in a dynamic ice bank system, and also uses this system to store ice. The object is to suitably carry out operation control for stopping and starting ice storage.

  To achieve the above object, the system of the present invention has an ice heat storage tank for storing ice / water slurry produced by a supercooler, and supplies cold water from the ice heat storage tank to a cooling load. In the dynamic ice bank system capable of both the ice storage operation and the ice-breaking operation, a detection sensor for detecting the amount of ice stored in the ice storage tank based on the rising height of the ice is provided. It is characterized by that.

  As a result of investigations by the inventors, it has been found that when ice is stored in a tank in an ice / water slurry state, there is a certain relationship between the rising state and the amount of ice stored. Therefore, the sherbet-like ice accumulates in the tank and the rising height is detected, so that the ice storage amount including the full storage state of the ice in the tank can be accurately known. The raised height here is the height from the water surface in the tank, and is the height up to the highest portion of the raised portions.

  As such a detection sensor, for example, an ultrasonic height meter that transmits an ultrasonic wave from above toward the ice of the ice heat storage tank and detects the rising height of the ice on the water surface can be mentioned. In addition, a laser-type distance meter or a distance meter based on capacitance detection may be used.

  In such an ice bank system, the return water from the cooling load is supplied into the ice heat storage tank so that the ice melting operation is performed, and the full ice storage rate (IPFfull) set in advance by the detection sensor. The maximum ice filling rate (IPFmax) is set between the minimum ice filling rate (IPFmin) at which cold water below a predetermined temperature can always be taken, and the ice filling rate in the ice heat storage tank is fully stored. When the ice filling rate (IPFfull) is exceeded, the ice storage operation is stopped, and when the ice filling rate in the ice heat storage tank becomes the maximum ice filling rate (IPFmax) or less, the ice storage operation is started. You may make it start.

  In deicing, there are a watering method in which water is sprinkled from above the ice in the tank, and a jet method in which water is sprayed on the ice in the tank from the lower side of the water surface in the tank to melt the ice. In the watering method, the return water from the cooling load is sprinkled on the upper surface of the ice layer from, for example, a spray nozzle provided in the upper part of the tank, and the ice is melted uniformly on the horizontal plane. In the jet system, the return water from the load is ejected from, for example, an underwater jet nozzle provided 100 to 200 mm below the water level in the tank to the ice layer to melt the ice.

  In the icing process using the sprinkling method, water is sprayed uniformly on the horizontal plane, so the rising height of the ice decreases as the amount of ice storage decreases, which is convenient for IPF detection based on the rising height of the ice. is there. Therefore, the de-icing operation is performed by supplying the return water from the cooling load into the ice heat storage tank, and the full ice storage rate (IPFfull) preset by the detection sensor and the chilled water always below the predetermined temperature. Set the maximum ice filling rate (IPFmax) with the minimum ice filling rate (IPFmin) that can be taken in, and the ice filling rate in the ice heat storage tank became more than the full ice filling rate (IPFfull) Of course, the ice storage operation is stopped at the time, and the ice storage operation is started when the filling rate of ice in the ice heat storage tank becomes equal to or less than the maximum ice filling rate (IPFmax). It is possible to use.

  However, in order to make the water spray from the spray nozzle to the ice layer uniform in a horizontal plane, a space height (distance between the ice layer and the spray nozzle) corresponding to the water spray angle of the spray nozzle is required. Due to this space, the volume in the tank cannot be effectively used for ice storage, so there is a point that a large tank is required compared to the jet method, and when the size of the tank is limited, it is not necessarily the best method I can't say that.

  In this point jet method, ice is melted under the water surface in the tank by the jet, and the ice melting process proceeds while the ice layer collapses, so that it is possible to save space in the height direction in the tank. However, due to the collapse of the ice layer during the ice-breaking process, depending on the height of the ice, it is expected that the ice storage rate, also called IPF (Ice Packing Factor), cannot be detected accurately.

  In view of this point, when the return water from the cooling load is supplied to the ice in the tank from the lower side of the water surface of the ice storage tank, the filling rate of ice is the maximum ice. Instead of starting the ice storage operation when the filling rate (IPFmax) or less is reached, the integrated value of the amount of cold water supplied to the cooling load is the total ice filling rate (IPFfull) and the maximum ice filling. It can be proposed that the ice storage operation is started when the ice storage amount (Qice) corresponding to the difference in the rate (IPFmax) is reached.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to detect appropriately the ice storage state of the ice in an ice thermal storage tank in a dynamic type ice bank system, and to suitably perform operation control of ice storage stop and ice storage start. is there.

  Embodiments of the present invention will be described below. FIG. 1 shows an outline of an ice bank system according to an embodiment, and a plurality of hollow water intake portions 2 made of punching metal or the like are provided at a lower portion in the ice heat storage tank 1. The water in the tank taken by the pump 4 through the first water intake pipe 3 communicating with the water intake unit 2 is sent to the supercooler 11, generated by the refrigerator 12, and supplied by the pump 14. Heat-exchanged with the frozen brine to produce supercooled water at 0 ° C. or lower. The subcooler 11 in the present embodiment employs a plate heat exchanger, but a shell and tube heat exchanger may also be used.

  The supercooled water produced by the supercooler 11 is sent to the supercooling releaser 13 to release the supercooled state, and becomes ice / water slurry, which is supplied into the ice heat storage tank 1 through the supply pipe 5. And stored in the tank. In the present embodiment, a plurality of discharge pipes 6 are vertically connected to a supply pipe 5 horizontally piped in the tank, and the tip of the discharge pipe 6 is piped so as to be located above the water surface in the tank. Has been. Therefore, as shown in FIG. 1, when ice / water slurry is spouted vertically from the tip of the discharge pipe 6, sherbet-like ice accumulates around the ice / water slurry.

  The cold water in the tank taken by the pumps 22a to 22c through the second water intake pipe 21 communicating with the water intake unit 2 is sent to the cooling load 23 as chilled cold water. The raised return water from the cooling load 23 is supplied into the ice heat storage tank 1 through the return water pipe 24. The outlet 24a in the tank of the return water pipe 24 is located 100 to 200 mm below the water surface in the tank. For example, as a jet nozzle configuration, the return water is jetted horizontally from the side toward the ice P, Thaw ice P to thaw.

  The second intake pipe 21 is provided with a flow meter 25 for measuring the flow rate of chilled cold water and a temperature sensor 26 for measuring the temperature of chilled cold water. The return water pipe 24 is also provided with a temperature sensor 27 for measuring the temperature of the return water. As a result, the integrated value of the supplied cold heat amount supplied to the cooling load 23 can be measured.

  A bypass pipe 28 is provided between the second intake pipe 21 and the return water pipe 24, and a flow rate control valve 29 is provided in the bypass pipe 28.

  Above the ice heat storage tank 1, an ultrasonic height meter 31 is provided that transmits ultrasonic waves toward the ice P in the ice heat storage tank 1 and detects the rising height of the ice on the water surface. . This ultrasonic height meter 31 measures the distance to an object by, for example, transmitting ultrasonic waves to the object, measuring the intensity of the reflected wave or transmitted wave from the object, the propagation time, etc. It is. The destination, that is, the point at which the height is measured, is preferably set at a location where the ice layer is thickest and is close to the discharge port of the discharge pipe 6. This is because the measurement point is too close to the discharge port to be affected by the flow of ice / water slurry that blows upward. Specifically, for example, a location approximately 30 cm away from the discharge port in the horizontal direction is appropriate.

  If the ultrasonic height meter 31 is used, the IPF of the ice P in the ice heat storage tank 1 can be measured by measuring the rising height of the ice P. The following are the results of actual verification by the inventors.

  FIG. 2 shows the relationship between the amount of ice storage and the rising height of ice. This is the result of confirming the reproducibility of the “relationship between the IPF and the rising height of ice” after four ice making (ice storage) operations. As shown in FIG. 2, the IPF is 20%. It was found that the rising height of ice was about 260 ± 25 mm, about 350 ± 25 mm when the IPF was 30%, and about 460 ± 25 mm when the IPF was 40%.

  The ice produced by this system is in the form of a slurry, and as shown in FIG. 3, the slurry-like ice supplied to the upper surface of the ice layer in the tank flows and accumulates in the lower part of the ice layer. Therefore, regardless of the remaining ice in the tank, the rising height at full storage, for example, the rising height when the IPF is 40%, is almost the same value every time. As a result of the confirmation test of such an event, FIG. 4 shows that when ice making (ice storage) with IPF of 35% or less to 40% or more and ice melting are repeated three times, and finally IPF is defrosted to 10% or less. This shows the time change of the rising height of ice together with the time change of IPF. The de-icing at this time is the jet method described above. According to this, it can be seen that the full storage state where the IPF is 40% can be detected with the rising height of the ice of 400 to 450 mm, as in the case where the ice making (ice storage) starts from 0%.

  In this way, by using the ultrasonic height meter 31, the rising height of the ice P, that is, the height h from the water surface L to the most raised portion is measured, so that the ice P in the ice heat storage tank 1 is measured. The IPF can be measured.

  The ice bank system of the present embodiment is controlled by the control device C. For example, the signals of the flow meter 25 that measures the flow rate of chilled cold water and the signals of the temperature sensors 26 and 27 that measure the temperature of chilled cold water are output to the control device C. Then, an integrated value of the amount of supplied cold heat supplied to the cooling load 23 is calculated. On the other hand, a height signal from the ultrasonic height meter 31 is also output to the control device C, and IPFfull is detected based on a preset height-full storage state. Based on these signals, the control device C controls the refrigerator 12, the pumps 4, 14 and the like to control the start and stop of the ice storage operation.

  In addition, the system configuration example shown in FIG. 1 shows the main part, and in the case of construction at an actual site, for example, the piping between the cooling load 23 and the ice heat storage tank 1 is not performed directly, As a radiator, a water-water heat exchanger is interposed, or for an ice making system, a water-water heat exchanger is interposed in the first intake pipe 3 to exchange heat with the circulation system to the cooling load. Then, the water after the temperature rise may be sent to the supercooler 11.

  Next, an example of operation control of the ice bank system according to the above configuration will be described. In this system, ice storage with an IPF of up to 50% is possible, but the maximum ice filling rate (IPFmax) is set when the IPF is 50% or less at a predetermined ice making capacity qice and a predetermined amount of water filling in the tank. The The premise that the IPF capable of storing ice is 50% is a value determined by the designer or operator that the system or the ice heat storage tank should not store any more from the viewpoint of durability.

  IPFmax is set as follows. First, the water intake temperature is calculated based on the time change of the cooling load under the maximum load condition of the cooling load 23, and the minimum ice filling rate IPF (IPFmin) at which water intake at a predetermined temperature or lower can always be obtained is obtained. When the generated load exceeds the ice storage capacity, the IPF decreases. Whether the decreased IPF falls below the IPFmin depends on the set value of IPFmax as described later. On the other hand, in order to suppress frequent start / stop of the refrigerator, it is better that the difference in IPF between the full storage detection IPF (IPFfull) and the IPFmax at which the ice storage operation is stopped is larger. That is, as the IPFmax is smaller, the frequency of frequent start / stop of the refrigerator decreases. The value of each IPF is 50% of IPF capable of storing ice ≧ IPFfull> IPFmax> IPFmin.

  Whether or not the decreasing IPF is lower than IPFmin depends on the set value of IPFmax as described above. This will be described in detail with reference to FIGS. 5 to 7. FIG. 5 shows an example of operation in which an ice bank capable of storing ice is 50%, IPFfull is 45%, IPFmax is 40%, and IPFmin is 20% in an ice bank system. Show. Here, the IPF (IPFfull) for full storage detection by the ultrasonic height meter 31 is set to a value obtained by subtracting the design margin IPF, for example, 5% from the above-mentioned ice storage capable IPF. In addition, this system is a system installed in a dairy product-related factory, for example. The manufacturing time zone of the factory is from 9:00 to 22:00, and the freezer is stopped at 22:00. However, for example, the product is stored at a low temperature thereafter. Therefore, it is a system that supports equipment under the condition that low load occurs due to such reasons and chilled cold water is supplied for 24 hours. And at the peak of the load, it is intended for facilities that generate loads exceeding the ice storage capacity. The allowable upper limit temperature of chilled cold water supplied to this facility is 1 ° C.

  As shown in FIG. 5, in this system, the amount of ice in the ice heat storage tank increases and decreases depending on the chilled load and the ice making capacity, and the IPF changes by 25% throughout the day. In the example of FIG. Since the IPFmax is appropriately determined, the IPF does not fall below 20% throughout the day, and therefore the temperature of the chilled cold water supplied does not exceed 1 ° C. Therefore, the setting that IPFmax is 40% is appropriate.

  However, in order to maintain the chilled cold water to be supplied at a low temperature, it is better that there is more ice in the ice heat storage tank. In other words, when there is little ice in the ice heat storage tank, that is, when the IPF is small, chilled cold water It becomes easy to raise the temperature. For example, as shown in FIG. 6, if the IPFmax is set to 35%, the IPF will be 15% from 15:00 to 18:00, the temperature of the chilled cold water supplied will be 1.1 ° C., and the allowable upper limit Exceeds the value of 1 ° C. Similarly, as shown in FIG. 7, when the IPFmax is set to 30%, the IPF becomes 10% from 15:00 to 18:00, and the temperature of the chilled cold water to be supplied becomes 1.2 ° C. It exceeds the upper limit of 1 ° C. Therefore, it is necessary to set the IPFmax so that the minimum IPF does not fall below the IPFmin in consideration of the IPF changing during one day in consideration of the load generation amount and the operation time.

  Then, the present system uses an IPF (full accumulation detection by the ultrasonic height gauge 31) based on the rising height of the ice layer between the IPFmax determined in this way and the IPF capable of storing ice (50%). IPFfull). By determining in this way, the maximum ice filling rate (IPFmax) is set between the full ice storage filling rate (IPFfull) and the minimum ice filling rate (IPFmin) at which cold water of a predetermined temperature or lower can always be taken. It will be. Then, an ice storage amount (Qice) corresponding to the difference between the full ice storage filling rate (IPFfull) and the maximum ice filling rate (IPFmax) is obtained in advance.

  When the supply operation to the chilled cold water to the cooling load 23 is started from the state where the ice storage operation is stopped in the fully stored state (= IPFfull) in the state set in this way, the supply of the cold water supplied to the cooling load 23 is started. When the integrated value of the amount of cold heat exceeds the ice storage amount (Qice) corresponding to the difference between the full ice storage filling rate (IPFfull) and the maximum ice filling rate (IPFmax), the refrigerator 12, the pumps 4, 14, etc. Is activated and ice storage operation is started.

  Then, when the ultrasonic height meter 31 detects the height of the full ice storage filling rate (IPFfull), the refrigerator 12, the pump 4 and the like are stopped, and the ice storage operation is stopped. Therefore, the ice storage operation is always performed with a target of a predetermined fully stored IPF (IPFfull), and an ice storage amount equal to or greater than the minimum IPF (IPFmin) is always ensured. In this case, when the load of the cooling load 23 is larger than the ice making capacity, the IPF decreases. Conversely, when the ice making capacity is larger than the cooling load, the IPF increases. Therefore, the ice making capacity of the supercooler 13 is the peak of the cooling load. It is desirable to set a larger value. Of course, as described above, it is necessary to set the IPFmax so that the changing IPF does not fall below the IPFmin when operated with respect to the target load.

  In addition, since it is not preferable to start and stop the refrigerator 12 in a short cycle, start and stop of the ice storage operation should be performed in consideration of the ON-OFF time of the refrigerator 12. Is preferred. For example, it is preferable to carry out the operation control so as to secure an interval of ON-OFF time of 0.5 hour or more.

  That is, the full ice storage rate (IPFfull) and the maximum ice filling rate (IPFmax) so that the time obtained by dividing the ice storage amount Qice corresponding to the difference between IPFfull and IPFmax by the ice making capacity qice is 0.5 hours or more. ) Is preferable.

As an example considering this, for example, when the ice making capacity qice is 140 [Rt] (423 [Mcal / h]) and the amount of water filling in the tank is 68 [m ³ ], The intake water temperature is calculated to determine IPFmin = 20% and IPFmax = 40%. Next, based on the rising height of the ice layer, for example, IPFfull is determined to be 45%. Therefore, IPF capable of storing ice is 50%, IPFfull is 45%, IPFmax is 40%, and IPFmin is 20%.

Then, Qice corresponding to 5% of the difference between IPFfull and IPFmax is 68 [m ³ ] × 80 [Mcal / m ³ ] × 0.05 / 3.024 = 90 [Rt · h] (272 [Mcal]). Yes, the time when this Qice is divided by qice is
90 [Rt · h] / 140 [Rt] = 0.64 [h].
Since this is 0.5 [h] or more, the refrigerator 12 is not frequently turned on and off. Therefore, if the integrated value of the supplied cold energy after full storage becomes 90 [Rt · h] (272 [Mcal]) or more, the ice making is set to start (restart), and the refrigerator 12 is turned ON− There is no frequent OFF.

  By the way, the amount of chilled cold water supplied to the cooling load 23 is integrated based on the flow rate and temperature of the intake water temperature, but the calculation of the intake water temperature based on the time change of the cooling load may include an error. In this case, the temperature of the chilled cold water supplied to the cooling load 23 may rise above a predetermined temperature.

  In order to cope with this, when the chilled cold water reaches a predetermined temperature (for example, 1 ° C.) or higher, the flow control valve 28 is opened. If it does so, the cold water taken from the ice thermal storage tank 1 will also be supplied to the return water pipe 24, the water temperature of the return water pipe 24 after joining will become low temperature, and the flow volume of water will increase. As a result, the temperature of water ejected from the outlet 24a in the tank via the return water pipe 24 becomes low, and the intake water temperature decreases. On the other hand, when the flow rate of water ejected from the outlet 24a is increased, the ejection flow rate is increased, and the melting performance of the ice P is improved.

  On the other hand, when the intake water temperature becomes 0.5 ° C. or lower when the flow control valve 29 of the bypass pipe 28 is open, the flow control valve 29 is closed. The temperature of the water in the return water pipe 24 detected by the temperature sensor 27 rises and the flow rate of the water decreases. When the temperature of the water ejected from the outlet 24a in the tank through the return water pipe 24 rises, the intake temperature also rises. On the other hand, when the flow rate of the water ejected from the outlet 24a is decreased, the ejection flow rate is decreased, and the melting performance of the ice P is lowered.

  Based on the temperature of the return water from the temperature sensor 27 as described above, the temperature control valve 29 of the bypass pipe 28 is controlled to open and close, whereby the temperature of the chilled cold water supplied to the cooling load 23 and the supply to the subcooler 11 are achieved. The temperature of the chilled water is maintained at a predetermined temperature, and it is possible to recover the rise in the water temperature of the chilled chilled water and to suppress the preheating of the water supplied to the subcooler 11 as much as possible, thereby realizing a highly efficient operation of this system. To do. Such control can also be performed by the control device C.

  INDUSTRIAL APPLICABILITY The present invention is useful for a system that supplies so-called chilled cold water, for example, cold water having a low temperature of 0 ° C. to 1.5 ° C., for example, to a food factory or a dairy product factory.

It is explanatory drawing which shows the structure of the ice bank system concerning embodiment. It is a graph which shows the relationship between the amount of ice storage (IPF) and the rising height of ice. It is explanatory drawing which showed typically a mode that slurry-form ice is supplied to the upper surface of the ice layer in a tank, flows into the low part of an ice layer, and ice accumulates. It is the graph which showed the time change of the rising height of ice when IPF repeated from 35% to 40% with the time change of IPF. It is a graph which shows the temperature of chilled cold water, and the change of IPF at the time of setting IPFmax to 40% at the time of applying the system which has a predetermined ice making capability with respect to the installation which has a predetermined load. It is a graph which shows the temperature of chilled cold water, and the change of IPF at the time of setting IPFmax to 35% at the time of applying the system which has a predetermined ice making capability with respect to the installation which has a predetermined load. It is a graph which shows the temperature of chilled cold water, and the change of IPF at the time of setting IPFmax to 30% at the time of applying the system which has a predetermined ice making capability with respect to the installation which has a predetermined load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ice thermal storage tank 2 Water intake part 3 1st water intake pipe 4, 14, 22a-22c Pump 5 Supply pipe 6 Discharge pipe 11 Supercooler 12 Refrigerator 13 Supercooler release device 21 2nd water intake pipe 23 Cooling load 24 Return Water pipe 24a Outlet 25 Flow meter 26, 27 Temperature sensor 28 Bypass pipe 29 Flow control valve 31 Ultrasonic height meter C Controller L Water surface P Ice

Claims (4)

An ice storage tank for storing ice / water slurry produced by a supercooler has both an ice storage operation and an ice removal operation configured to supply cold water from the ice storage tank to a cooling load. In a dynamic ice bank system,
An ice bank system comprising a detection sensor for detecting an ice storage amount in the ice heat storage tank based on a rising height of ice. 2. The ultrasonic sensor according to claim 1, wherein the detection sensor is an ultrasonic height meter that transmits an ultrasonic wave from above toward the ice in the ice heat storage tank to detect a rising height of ice on a water surface. The ice bank system described in 1. In the ice bank system according to claim 1 or 2,
Supplying the return water from the cooling load into the ice heat storage tank so that the ice melting operation is performed,
A maximum ice filling rate (IPFmax) is set between a full ice filling rate (IPFfull) set in advance by the detection sensor and a minimum ice filling rate (IPFmin) at which cold water of a predetermined temperature or lower can always be taken,
The ice storage operation is stopped when the filling rate of ice in the ice heat storage tank becomes equal to or higher than the full ice storage filling rate (IPFfull), and the filling rate of ice in the ice heat storage tank is equal to the maximum ice filling rate. An ice bank system operation control method, wherein ice storage operation is started when the rate (IPFmax) or less is reached. The return water from the cooling load is supplied to the ice in the tank from the lower side of the water surface of the ice heat storage tank so that the ice is melted.
Instead of starting the ice storage operation when the ice filling rate is less than the maximum ice filling rate (IPFmax),
When the integrated value of the amount of cold water supplied to the cooling load becomes equal to or greater than the ice storage amount (Qice) corresponding to the difference between the full ice storage filling rate (IPFfull) and the maximum ice filling rate (IPFmax). The operation control method for the ice bank system according to claim 3, wherein the ice operation is started.

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