JP2004361053A - Ice heat storage device, and ice heat storage method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ice heat storage device with superior temperature control of cold water, achieving further labor-saving of ice making, and capable of preventing freezing of a cold water passage and an ice water passage during ice water production by controlling preheating of the cold water. <P>SOLUTION: An ice heat storage tank 8, a cold water preheating device 3, and a supercooler 5 are respectively connected by the cold water passage 62, and a cold water bypass passage 68 is connected for sending the cold water from the ice heat storage tank 9 to the supercooler 5 without going through the cold water preheating device 3. In the cold water preheating device 3, a preheater 19, first and second expansion valves 27 and 28, an evaporator 21, a compressor 23, a condenser 25, and a refrigerant liquid tank 26 are connected by a refrigerant line 61, the evaporator 21, the supercooler 5 preheater are composed so as to share brine, and a refrigerant bypass line 66 is provided having a starting point in an upstream side of the preheater 19. A temperature of the cold water is controlled by existence or non existence of preheating and increase and decrease of preheating, and preheating of the cold water is carried out by controlling a liquid refrigerant amount so that the preheater 19 is filled with refrigerant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ice heat storage device that performs ice heat storage using supercooled water and a chilled water preheating device used for the ice heat storage device.
[0002]
[Prior art]
In the field of air conditioning equipment such as cooling and heating, ice is used as a heat storage medium as a type of heat storage system that stores heat in a heat storage medium.In the production of this ice, the water is cooled to a supercooled state and then released from the supercooled state. BACKGROUND ART An ice heat storage device and an ice heat storage method for generating ice water have been conventionally known.
[0003]
In the ice heat storage device, an ice heat storage tank for storing water and ice, and a supercooler for cooling cold water supplied from the ice heat storage tank to a supercooled state are used. A chilled water preheating device that adjusts the temperature of chilled water before supercooling is used to prevent freezing of the chilled water. As the chilled water preheating device, a system using a heat pump is known in addition to a heat exchanger that guides return water from an electric heater or an air conditioning load and water flowing to a cooling tower.
[0004]
As the ice heat storage device having the above-described cold water preheating device, for example, an ice heat storage tank for storing water and ice, a cold water preheating device for adjusting the temperature of the cold water supplied from the ice heat storage tank, and a temperature-controlled cold water A subcooler that cools to a supercooled state, wherein the ice water storage device that releases ice from the supercooled water to generate ice is provided. A preheater for exchanging heat between the preheating device, a decompression device that expands the refrigerant used for preheating to reduce the pressure of the refrigerant, an evaporator that evaporates the depressurized refrigerant, and a compressor that compresses the vapor refrigerant, There is known an ice heat storage device having a condenser that condenses compressed refrigerant to generate a refrigerant accommodated in a preheater, and a refrigerant bypass flow path that connects flow paths upstream and downstream of the preheater. (See, for example, Patent Document 1) ).
[0005]
This ice heat storage device is intended to appropriately adjust the temperature of the cold water by appropriately distributing the refrigerant flowing to the preheater and the refrigerant bypass flow path and adjusting the flow rate of the refrigerant to the preheater.
[0006]
Also, as an ice heat storage device, for example, an ice heat storage device that self-produces cold heat in a supercooler and a chilled water preheating device by sharing and circulating brine between a supercooler and a chilled water preheating device is known. (For example, see Patent Document 2). This ice heat storage device is an excellent device for suppressing the complexity of the structure and the accompanying cost increase, since there is no need to provide a separate heat source for melting ice contained in cold water before supercooling. is there.
[0007]
Further, as an ice heat storage method, for example, an ice heat storage method in which cold water having a temperature exceeding the freezing point is injected into ice water after supercooling is released (for example, see Patent Document 3). This ice heat storage method is an excellent method for preventing ice water generated by releasing supercooling from being frozen in an ice water flow path during an unstable period such as when the system is started.
[0008]
[Patent Document 1]
JP-A-10-288361
[Patent Document 2]
JP-A-10-185248
[Patent Document 3]
JP-A-10-122610
[0009]
[Problems to be solved by the invention]
The ice heat storage device described in Patent Literature 1 is excellent in temperature control of chilled water, but leaves room for study on complicating the structure, increasing the cost, and improving the space factor. Further, the ice heat storage device described in Patent Document 2 is excellent in reducing the initial cost and the running cost, but leaves room for study on the temperature adjustment of the chilled water and the further improvement of the ice-making ability.
[0010]
In the ice heat storage device, since the refrigerant is condensed in the condenser, the refrigerant supplied to the preheater is composed of a liquid and a gas in a saturated state at that temperature. The refrigerant in a gaseous state changes phase when preheating the cold water and becomes a liquid refrigerant. That is, the refrigerant in the gaseous state has a higher heating capacity than the liquid refrigerant because latent heat can be used for preheating the cold water. However, in a self-manufactured ice heat storage device, this latent heat is heat to be discarded by the evaporator (supercooling of the cold water). It is not preferable to use the latent heat of the refrigerant for the preheating of the cold water from the viewpoint of labor saving in the process of making ice and generating the cold heat.
[0011]
In the ice heat storage device described above, the supercooled water is subjected to impact energy such as falling energy to change the phase of the supercooled water to generate sherbet-shaped ice water. When the degree of supercooling of the cold water at the outlet is small, the subsequent supercooling release is insufficient, and the supercooled state is gradually released in the ice water flow path, and ice may be formed in the ice water flow path.
[0012]
Although the above-described scene can be avoided in the ice heat storage method described in Patent Literature 3, since ice water is prevented from freezing by injecting cold water into the generated ice water, loss of the generated ice water is included. There is still room for study from the viewpoint of the generation efficiency of.
[0013]
The first object of the present invention is to provide a self-manufacturing type ice heat storage device that is excellent in temperature control of cold water and achieves further labor saving in ice making.
A second object of the present invention is to prevent the freezing of the cold water flow path and the ice water flow path by controlling the preheating of the cold water at the time of ice water generation in the ice heat storage method.
[0014]
[Means for Solving the Problems]
<Ice heat storage device of the present invention>
The present invention provides at least a means for solving the first problem, a supercooler for cooling water to a supercooled state, and an ice heat storage for storing ice and water generated by releasing the supercooled state of the supercooled water. A tank, a cold water preheating device that adjusts the temperature of the cold water supplied from the ice heat storage tank to the subcooler, and an ice heat storage device that has a temperature detection unit that detects the temperature of the cold water. A preheater that contains the refrigerant and exchanges heat between the refrigerant and the cold water, a decompression device that expands the refrigerant to reduce the pressure of the refrigerant, an evaporator that evaporates the depressurized refrigerant, and compresses the vapor-state refrigerant Compressor that condenses the compressed refrigerant to generate refrigerant contained in the preheater, and refrigerant amount control that controls the amount of liquid refrigerant in the preheater so that the preheater is filled with liquid refrigerant Means, and the subcooler comprises: The brine cooled by the originating device to provide an ice thermal storage apparatus characterized by cooling the cold water supercooled state.
[0015]
According to the above configuration, since the flow rate of the liquid refrigerant supplied to the preheater can be controlled, appropriate temperature adjustment of the cold water can be performed. Further, according to the above configuration, since the preheater can be filled with the liquid refrigerant, the temperature of the chilled water can be adjusted by the sensible heat of the liquid refrigerant, and the temperature of the chilled water guided to the supercooler can be adjusted in a gaseous state. Since the latent heat of the refrigerant is not used, it is possible to achieve more energy-efficient preheating of the chilled water than in the case of preheating the chilled water with the refrigerant containing the gaseous refrigerant in the self-manufactured ice storage device, and the self-production In the ice storage device of the type, further labor saving of ice making can be achieved.
[0016]
In the present invention, various types of conventionally known ice heat storage tanks can be used as the ice heat storage tank.
[0017]
In the present invention, the subcooler is not particularly limited as long as it is a supercooler configured to generate cold heat in the chilled water preheating device. As such a subcooler, as conventionally known, a subcooler that shares a brine with an evaporator in a chilled water preheating device can be exemplified. With such a configuration, an ice heat storage device capable of generating cold heat used for preheating (heating) and cooling (supercooling) of cold water in the device is configured. As for the configuration in which the evaporator and the subcooler share brine, the configuration described in the above-mentioned Japanese Patent Application Laid-Open No. 10-185248 can be suitably used.
[0018]
Known means such as a thermometer can be used as the temperature detecting means. The arrangement of the temperature detecting means is not particularly limited as long as the temperature of the chilled water is detected, since the cooling temperature difference of the chilled water in the supercooler is generally constant. It can be provided at any position up to a position where the temperature of the cold water can be detected. Generally, this is the outlet of an ice thermal storage tank. By providing the temperature detecting means, it is possible to realize appropriate preheating of the cold water according to the temperature of the cold water.
Hereinafter, the cold water preheating device used in the present invention will be described.
[0019]
The chilled water preheating device used in the present invention is characterized by having the refrigerant amount control means, but a heat pump system conventionally known can be used as the other configuration. Such systems include a series of devices consisting of a preheater, a decompressor, an evaporator, a compressor, and a condenser. Therefore, the preheater, the decompression device, the evaporator, the compressor, and the condenser used in the present invention include those conventionally known as components of the heat pump, and components similar thereto (the components having the above-described functions). Can be used. In the present invention, when configuring the chilled water preheating device with the preheater or the like, an automatic valve or various sensors may be appropriately used to realize desired operating conditions.
[0020]
Further, as the refrigerant and the brine used in the present invention, various refrigerants and brine applied to the heat pump can be used as in the above-described constituent elements. In addition, the types of refrigerant and brine used in the present invention depend on various conditions suitable for the ice heat storage device of the present invention in terms of thermodynamic properties such as latent heat and sensible heat, chemical properties such as stability, and economic efficiency. It is preferable to select.
[0021]
Hereinafter, the refrigerant amount control means in the chilled water preheating device used in the present invention will be described.
[0022]
The refrigerant amount control means is a means for controlling the amount of the liquid refrigerant in the preheater so that the preheater is filled with the liquid refrigerant, the present invention is not particularly limited as long as it has such a function, Various configurations having the above functions can be used alone or in combination. In the present invention, "the preheater is filled with the liquid refrigerant" refers to a state in which a heat exchange portion of the preheater that exchanges heat between the refrigerant and the cold water is immersed in the liquid refrigerant.
[0023]
In the present invention, the heating amount of the cold water in the preheater can be controlled by the refrigerant amount control means as described above. Here, the amount of heating by the chilled water preheating device varies depending on the operating conditions of the ice heat storage device, the surrounding environment, and the like, but is preferably 20 to 25% of the preheating capability of the chilled water preheating device. If the heating amount is less than 20% of the preheating capacity, icing of cold water may occur before the supercooler. If the heating amount exceeds 25% of the preheating capacity, further labor saving in ice making is not achieved or the cooling of the cold water is insufficient. Etc. may occur.
[0024]
As the refrigerant amount control means as described above, for example, a flow rate adjusting means such as an automatic valve provided in a refrigerant flow path downstream of the preheater, and a refrigerant sufficient for the preheater to immerse the heat exchange portion in the refrigerant. And a liquid level meter for detecting the liquid level position of the refrigerant, wherein the flow rate of the refrigerant is adjusted by the flow rate adjusting means depending on whether or not the liquid level is detected by the liquid level meter. The liquid level gauge can be provided at an arbitrary position in the flow path above the liquid level position (but fluctuates) and below the condenser.
[0025]
Further, the refrigerant amount control means includes a refrigerant bypass flow path connecting two points of a refrigerant flow path circulating through the preheater in the refrigerant flow path, and a refrigerant distribution means for distributing the condensed refrigerant to the preheater and the refrigerant bypass flow path. It is preferable that the configuration has the following. According to such a configuration, it is possible to more appropriately control the flow rate of the refrigerant required for preheating the cold water to the preheater.
[0026]
Note that the refrigerant bypass flow path is downstream of the liquid level position of the refrigerant sufficient for the refrigerant to immerse the heat exchange site in the preheater in the condenser, and in the flow path on the upstream side of the flow of the refrigerant than the preheater. It may have a starting point at an arbitrary position, and may have an end point at an arbitrary position in a flow path downstream of the preheater and upstream of the pressure reducing device.The refrigerant bypass flow path may be, for example, as described above. An overflow flow channel that secures the liquid level of the refrigerant specified in (1) can be exemplified.
[0027]
As the refrigerant distribution means, for example, a three-way cock that is provided at the starting point of the refrigerant bypass flow path and divides the flow path of the refrigerant into a desired ratio, and a flow rate that is provided in the refrigerant bypass flow path and the flow path downstream of the preheater Adjustment valves and the like can be exemplified, and these valves are preferably automatic valves. The refrigerant distributing means preferably has a configuration interlocked with the liquid level gauge, and distributes the refrigerant at least based on whether or not the liquid level of the refrigerant is at an appropriate liquid level position. In the case where an automatically controlled expansion valve is used as the pressure reducing device, the configuration can be simplified by using the pressure reducing device also as a refrigerant distribution unit.
[0028]
The refrigerant amount control means includes a refrigerant liquid tank provided above the preheater for storing the refrigerant condensed by the condenser, and a liquid level meter for detecting the liquid level of the refrigerant stored in the refrigerant liquid tank. It is preferable to further include a detection unit. According to such a configuration, it is possible to more reliably control the amount of the liquid refrigerant so that the preheater is filled with the liquid refrigerant. In such a configuration, the refrigerant bypass flow path has a starting point at an arbitrary position in the refrigerant flow path downstream of the refrigerant liquid tank and upstream of the preheater.
[0029]
The above-described liquid level gauge can be used as the level detecting means. The level detecting means may be a means for detecting the liquid level position of the refrigerant in the refrigerant liquid tank at any time, or a predetermined refrigerant liquid level position in the refrigerant liquid tank (for example, the upper limit position and the liquid level of the refrigerant in the refrigerant liquid tank). (For example, at the lower limit position of the surface) to detect only the presence or absence of contact.
[0030]
According to the chilled water preheating device configured as described above, by controlling the amount of the liquid refrigerant in the preheater, appropriate temperature adjustment of the chilled water and further labor saving of ice making are achieved, but the control condition of the refrigerant amount is set. It may deviate from the original condition. If left unattended in such a case, there is a risk that the ice-making ability will be reduced and hindrance will be caused. Therefore, the present invention provides a configuration that can cope with the above case.
[0031]
Among the above cases, in the present invention as a configuration corresponding to the case where the retained sensible heat amount of the liquid refrigerant is excessive with respect to the chilled water preheat amount, the chilled water flow path downstream of the ice heat storage tank and the upstream of the supercooler A chilled water bypass passage connecting the chilled water flow passages on the side, and a chilled water distributing means for distributing the chilled water to the chilled water preheating device and the chilled water bypass flow passage based on the detection result by detecting the temperature of the chilled water by the temperature detecting means. provide.
[0032]
In the above case, it is possible to sufficiently cope with the control of the amount of refrigerant in the chilled water preheating device. However, according to the above configuration, the chilled water flow path of the ice heat storage tank → the chilled water preheating device → the supercooler, and the ice heat storage Either or both of the cold water flow path from the tank to the supercooler can be selected, and the supply of cold water whose temperature has increased due to excessive preheating can be suppressed before supercooling, which hinders ice making This is preferable for avoiding the scene and quickly returning to normal operation. Note that the above-described configuration is not necessarily used only when the preheating is excessive, and may be used during normal operation as a configuration that assists the preheating control of the chilled water by the chilled water preheating device.
[0033]
The chilled water bypass channel, the chilled water distribution unit, and the temperature detection unit can be configured in the same manner as the refrigerant bypass channel, the refrigerant distribution unit, and the temperature detection unit described above. The chilled water bypass passage has a starting point at an arbitrary position in the chilled water passage (pipe) from the ice storage tank to the chilled water preheating device, and the chilled water passage (pipe) from the chilled water preheating device to the supercooler. May have an end point at an arbitrary position in.
[0034]
When the preheating is excessive, it is effective to stop the heat exchange between the cold water and the refrigerant. As for the stop of the heat exchange, there are modes such as a stop of the supply of the cold water to the cold water preheating device and a stop of the operation of the cold water preheating device. When appropriate measures are taken by the means and measures described above, normal operation is restored.
[0035]
In addition, among the above-mentioned cases, the present invention has a configuration capable of coping with a case in which the sensible heat amount of the liquid refrigerant is insufficient with respect to the preheating amount of the chilled water due to a decrease in the cooling capacity of the cooling means used in the condenser or the type of the refrigerant. In the present invention, the refrigerant amount control means provides a configuration for controlling the amount of the liquid refrigerant in the preheater such that the gaseous refrigerant is introduced into the preheater when the sensible heat in the liquid refrigerant is insufficient. In the above case, the refrigerant amount control means controls the flow rate adjusting means, the refrigerant distribution means, and the like to control the amount of the liquid refrigerant so that the liquid refrigerant flows out of the preheater.
[0036]
According to such a configuration, further labor saving of ice making is impaired, but it is possible to prevent icing of cold water before supercooling, and it is possible to avoid a situation that hinders ice making. Become.
[0037]
The ice heat storage device of the present invention has a warning device that informs a system administrator that a gaseous refrigerant has been introduced into a preheater, and is provided at an ice heat storage tank outlet and operates only in the above case to heat cold water. A heating device or the like may be provided as auxiliary means.
[0038]
<The ice heat storage method of the present invention>
The present invention adjusts the temperature of cold water supplied from an ice heat storage tank that stores water and ice with a cold water preheating device as a means for solving at least the second problem, and uses a supercooler to cool the temperature-controlled cold water. In the ice heat storage method of generating ice by cooling to the supercooled state and releasing the cooled water in the supercooled state, the temperature of the cold water is detected by the temperature detecting means, and the supercooling is released at the time of preheating by the cold water preheating device. When the temperature of the previous chilled water reaches the subcooling release insufficient temperature range, the preheating of the chilled water by the chilled water preheating device is stopped until the temperature of the chilled water escapes the subcooling release insufficient temperature range by cooling by the subcooler. An ice heat storage method is provided.
[0039]
According to the ice heat storage method described above, since the temperature of the chilled water quickly escapes (skips) from the subcooling release insufficient temperature range, the occurrence of the undercooling release insufficient is suppressed, and ice water is generated by the subcooling release. It is possible to prevent freezing of the ice water flow path due to the insufficient degree of supercooling in the initial stage of operation of the ice heat storage device or the like. In addition, the shortage of supercooling is quickly eliminated, which is advantageous in further improving the efficiency of ice water generation.
[0040]
The subcooling release under-temperature range is defined as the temperature of the ice water in which the supercooled cold water does not freeze even after the supercooling is released, and the supercooled state is gradually released in the ice water flow path and may freeze in the ice water flow path. This is a temperature range, which is slightly different depending on environmental fluctuations, cold water conditions, and the like, but is generally −0.5 to 0 ° C. After reaching the undercooling release insufficient temperature range, the preheating of the chilled water may be stopped from an arbitrary temperature in the temperature range, but stopping the preheating of the chilled water at the upper limit of the temperature range suppresses the occurrence of the undercooling release shortage. It is preferable in doing.
[0041]
By the way, in the early stage of the operation of the ice heat storage device, the chilled water is cooled by the supercooler, but it is not necessary to operate the chilled water preheating device because the temperature of the chilled water is higher than the freezing point. However, if the chilled water is to be cooled to the supercooled state as it is, icing may occur in the chilled water flow path before skipping the subcooling release insufficient temperature range. On the other hand, operating the chilled water preheating device from the initial operation of the ice heat storage device in order to prevent icing in the chilled water flow path is not preferable from the viewpoint of saving labor in ice making.
[0042]
Therefore, in the ice heat storage method of the present invention, when the temperature of the chilled water before the supercooling is released falls to the chilled water unstable temperature range without being preheated by the chilled water preheating device, the temperature of the chilled water is reduced by the cooling by the subcooler to prevent the chilled water from being cooled. It is preferable to preheat the chilled water by the chilled water preheating device until the temperature falls out of the stable temperature range.
[0043]
The cold water unstable temperature range refers to a temperature range of cold water in which ice may easily be generated due to conditions such as the presence of an object that can be a nucleus (for example, fine ice particles or foreign particles such as dust) in the cold water. In general, the temperature is 0 to 0.5 ° C., although it slightly varies depending on environmental fluctuations, the state of cold water, and the like.
[0044]
According to the preheating of the cold water described above, even if freezing occurs in the cold water in the cold water unstable temperature range, it can be melted. After reaching the chilled water unstable temperature range, the chilled water may be preheated from an arbitrary temperature in the temperature range, and the chilled water may be preheated to maintain a temperature near the upper limit of the temperature range.
[0045]
In the ice heat storage method of the present invention, the preheating of the chilled water is controlled by detecting the temperature of the chilled water. Here, regarding the detection of the chilled water temperature, the temperature difference before and after cooling by the supercooler is generally substantially constant. If the temperature of the chilled water is not particularly limited because the temperature difference is reflected, the temperature of the chilled water in the flow channel is immediately reflected by the effect of preheating by the chilled water preheating device and cooling by the supercooler. Detecting the temperature of the chilled water at the outlet of the supercooler is more preferable in order to confirm the temperature of the supercooled water.
[0046]
The ice heat storage method of the present invention is realized by using various conventionally known ice heat storage devices as long as the ice heat storage device has a cold water preheating device that preheats cold water before being cooled to a supercooled state. However, it is preferable to use the above-described ice heat storage device of the present invention in the ice heat storage method of the present invention from the viewpoint of economy and the like.
[0047]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
As shown in FIG. 1, the ice heat storage device in the present embodiment includes an ice heat storage tank 9 for storing cold water 15 and ice 13, a cold water preheating device 3 for adjusting the temperature of the cold water supplied from the ice heat storage tank 9, It has a supercooler 5 for cooling the adjusted cold water to a supercooled state, and a supercooling release tank 7 for releasing the supercooled state of the supercooled water by falling energy. The ice heat storage tank 9 is connected to the cold water preheating device 3, and the cold water preheating device 3 and the supercooler 5 are connected by a cold water channel 62, and the supercool release tank 7 and the ice heat storage tank 9 are connected by an ice water channel 64. . The chilled water flow passage 62 is provided with a chilled water bypass flow passage 67 that leads from the ice heat storage tank 9 to the supercooler 5 without passing through the chilled water preheating device 3.
[0048]
A first thermometer 37 for detecting the temperature of the chilled water is provided in the chilled water channel 62 upstream of the starting point of the chilled water bypass channel 67, and is provided downstream of the end point of the chilled water bypass channel 67. A second thermometer 38 for detecting the temperature of the chilled water is provided in the chilled water channel upstream of the subcooler 5. A chilled water preheating pump 17 for sending chilled water to be preheated to the chilled water preheating device 3 is provided in the chilled water flow channel 62 downstream of the starting point of the chilled water bypass flow channel 67 and upstream of the chilled water preheating device 3. The chilled water circulation passage 18 is provided in the chilled water bypass passage 67. The first and second thermometers 37 and 38 are temperature detecting means in the present invention, and the cold water preheating pump 17 and the cold water circulation pump 18 are cold water distributing means in the present invention. The chilled water distributing means is such that one pump is interposed between the second thermometer 38 and the supercooler 5 in FIG. 1 and valves are provided in the chilled water bypass passage 67 and the chilled water passage 62. Thereby, the chilled water preheating pump 17 and the chilled water circulation pump 18 can be omitted.
[0049]
The chilled water preheating device 3 is, for example, a plate type heat exchanger, a cell and tube type heat exchanger, or the like, and stores a refrigerant and exchanges heat between the refrigerant and the chilled water. First and second expansion valves 27 and 28, an evaporator 21 for evaporating a refrigerant in a reduced pressure state, a compressor 23 for compressing a refrigerant in a vapor state, and a condenser 25 for condensing the compressed refrigerant. And a refrigerant liquid tank 26 for storing the condensed refrigerant. The refrigerant liquid tank 26 is provided above the preheater 19.
[0050]
The preheater 19, the first expansion valve 27, the evaporator 21, the compressor 23, the condenser 25, and the refrigerant liquid tank 26, and the refrigerant liquid tank 26 and the preheater 19 are connected to each other through the refrigerant flow path 61. Further, the refrigerant flow path 61 of the refrigerant circulating through the preheater 19 is connected by a refrigerant bypass flow path 66. The refrigerant bypass flow path 66 has a starting point in the refrigerant flow path 61 downstream of the refrigerant liquid tank 26 and upstream of the preheater 19, and refrigerant downstream of the preheater 19 and upstream of the evaporator 21. It has an end point in the channel. A second expansion valve 28 is provided in the refrigerant bypass passage 66.
[0051]
The first and second expansion valves 27 and 28 are automatic valves, are pressure reducing devices in the present invention, are refrigerant amount control means, and are refrigerant distribution means in the present invention.
[0052]
The evaporator 21 shares the brine with the subcooler 5, and the evaporator 21 and the subcooler 5 are connected by a brine channel 63. The brine circulation pump 30 is provided in the brine channel 63.
[0053]
The condenser 25 uses the cooling tower 11 as a cooling heat source to cool and condense the refrigerant in a vapor state. The condenser and the cooling tower 11 are connected by a cooling water passage 65, and the cooling water passage 65 is provided with a cooling water circulation pump 33 and a third thermometer 39 for detecting the temperature of the cooling water discharged from the condenser 25. Is provided.
[0054]
The refrigerant liquid tank 26 is provided with first and second liquid level gauges 35 and 36 for detecting the liquid level of the refrigerant stored in the refrigerant liquid tank 26. The first and second liquid level gauges 35 and 36 are level detecting means in the present invention. The first liquid level gauge 35 detects a low liquid level of the refrigerant liquid tank 26, and the second liquid level gauge 36 is The high liquid level of the refrigerant liquid tank 26 is detected.
[0055]
The first, second, and third thermometers 37, 38, and 39 are connected to a temperature value collection panel (TGP), and the TGP is connected to a temperature indicating controller (TIC). And the second expansion valves 27 and 28. Although not shown, the first and second expansion valves 27 and 28 are connected to the first and second liquid level gauges 35 and 36, respectively. The first and second expansion valves 27 and 28 reduce the pressure of the refrigerant and distribute the refrigerant according to the temperature of the chilled water, the temperature of the chilled water, and the amount of the liquid refrigerant.
[0056]
Hereinafter, an operation state of the ice heat storage device in the present embodiment will be described. First, circulation of cold water and ice water will be described.
[0057]
The cold water is sent from the ice heat storage tank 9 to one or both of the preheater 19 and the subcooler 5 through the cold water channel 62. At this time, the supply destination of the cold water and the ratio thereof are determined by the operation status of the cold water preheating pump 17 and the cold water circulation pump 18.
[0058]
When the whole amount of the cold water is supplied to the preheater 19, the cold water circulation pump 18 is stopped, and the cold water is supplied by the cold water preheating pump 17. In the case where the whole amount of the cold water is supplied to the supercooler 5 without preheating, the cold water preheating pump 17 is stopped and the cold water circulation pump 18 sends the cold water. When the cold water is supplied from the ice heat storage tank 9 to both the preheater 19 and the supercooler 5, the cold water is sent by both the cold water preheating pump 17 and the cold water circulation pump 18. Note that the cold water supplied to the preheater 19 is sent to the subcooler 5.
[0059]
The cold water supplied to the supercooler 5 is cooled, and the cold water cooled to the supercooled state is supplied to the subcooling release tank 7 to become sherbet-like ice water. The generated ice water is sent to the ice heat storage tank 9 through the ice water flow path 64.
[0060]
Next, circulation of the refrigerant in the cold water preheating device 3 will be described.
The refrigerant accommodated in the refrigerant liquid tank 26 is sent from the refrigerant liquid tank 26 to the preheater 19 through the refrigerant flow channel 61 during a steady operation other than the start-up. Since the refrigerant liquid tank 26 is located above the preheater 19 and the refrigerant bypass passage 66 and the first and second expansion valves 27 and 28 are provided, the refrigerant is stored in the refrigerant liquid tank 26. In this case, the refrigerant flow path (including the refrigerant bypass flow path 66) from the preheater 19 and the refrigerant liquid tank 26 to the first and second expansion valves 27 and 28 is filled with the refrigerant.
[0061]
When the entire amount of the refrigerant in the refrigerant liquid tank 26 is supplied to the preheater 19, the second expansion valve 28 is fully closed. When the entire amount of the refrigerant in the refrigerant liquid tank 26 is supplied to the second expansion valve 28, the first expansion valve 27 is fully closed. When supplying the refrigerant to both the preheater 19 and the second expansion valve 28, both the first and second expansion valves 27 and 28 are opened. The refrigerant supplied to the preheater 19 is sent to the first expansion valve 27.
[0062]
The distribution ratio of the refrigerant to the preheater 19 and the second expansion valve 28 is arbitrarily set depending on the degree of opening of both expansion valves. The distribution ratio of the refrigerant is determined by the cold water temperature detected by the first and second thermometers 37 and 38, the cooling water temperature detected by the third thermometer 39 used in the condenser 25, and the refrigerant liquid tank 26. Is determined by the detection results of the first and second liquid level gauges 35 and 36 provided in the first and second liquid level gauges.
[0063]
The refrigerant sent to the first and second expansion valves 27 and 28 has a pressure that decreases with passage of the expansion valves, and a part of the refrigerant changes to a gas, and the refrigerant that has changed to a gaseous state cools the remaining liquid refrigerant, In this state, it is sent to the evaporator 21. The refrigerant sent to the evaporator 21 removes heat from the brine supplied from the subcooler 5 and evaporates. The heat deprived (cooled brine) is sent to the supercooler 5 and used for cooling the cold water.
[0064]
The refrigerant in a vapor state is sent from the evaporator 21 to the compressor 23. In the compressor 23, the refrigerant in a vapor state is compressed and is sent to the condenser 25 in a state of high temperature and high pressure. The refrigerant sent to the condenser 25 is condensed by being cooled by the cooling water. Since the pressure in the condenser 25 is sufficiently high, the gaseous refrigerant condenses to a liquid state even at a relatively high temperature.
[0065]
The refrigerant condensed in the condenser 25 is sent to the refrigerant liquid tank 26. The refrigerant liquid tank 26 stores a liquid refrigerant.
[0066]
Next, the operation state of the ice heat storage device will be described under various conditions, and an embodiment of the ice heat storage method of the present invention will be described.
[0067]
<Normal operation>
The temperature of the chilled water preheated by the refrigerant (supercooler inlet temperature) is set to 0.5 ° C., and the flow rate of the chilled water to the preheater 19 is reduced to 1 / (the total flow rate of the chilled water) depending on the operating conditions of the chilled water preheating pump 17 and the chilled water circulation pump 18. The case where the number is 10 will be described as an example. The circulation amount of the refrigerant in the chilled water preheating device 3 is determined by the output of the chilled water preheating device 3. In the present embodiment, the opening degree of the first expansion valve 27 is adjusted so that the refrigerant temperature at the outlet of the preheater 19 becomes 5 ° C. Shall be adjusted. The temperature difference of the cold water before and after the supercooler 5 is constant at 2.5 ° C. When the temperature of the cold water is 0 ° C. or higher, preheating of the cold water is not performed because there is no ice in the cold water, and the case of performing the preheating of the cold water will be described.
[0068]
The amount of sensible heat held by the refrigerant is determined by the amount of refrigerant sent to the preheater 19 and the condensation temperature. When the preheating by the refrigerant is being performed appropriately (when the liquid level of the refrigerant liquid tank 26 is sufficient as shown in FIG. 1), the first liquid level gauge 35 detects a decrease in the liquid level of the liquid refrigerant. If not, the refrigerant is circulated in the chilled water preheating device 3 while maintaining the state of the liquid refrigerant level between the first and second liquid level gauges.
[0069]
If the sensible heat of the refrigerant is lower than the required amount of cold water preheating, it can be dealt with by increasing the amount of refrigerant sent to the preheater 19 and lowering the condensing temperature. The increase in the amount of the refrigerant is adjusted in a direction in which the second expansion valve 28 is closed. Regarding the decrease in the condensing temperature, the cooling water circulation pump 33 is adjusted to increase the circulation amount of the cooling water.
[0070]
If the sensible heat of the refrigerant exceeds the required amount of chilled water preheating, the reduction in the amount of refrigerant sent to the preheater 19, the increase in condensation temperature, and the increase in the amount of chilled water supplied to the preheater 19 must be handled. Can be. The amount of the refrigerant is adjusted in a direction in which the first expansion valve 27 is closed. The rise in the condensing temperature is adjusted by the cooling water circulation pump 33 so as to reduce the circulation amount of the cooling water. The supply amount of the cold water to the preheater 19 is adjusted in such a manner that the ratio of the cold water supplied to the preheater 19 by the cold water preheating pump 17 and the cold water circulation pump 18 is increased.
[0071]
When the liquid level of the liquid refrigerant is detected by the first liquid level gauge 35, the adjustment is performed in a direction to close one or both of the first and second expansion valves 27 and 28. Further, the adjustment is performed in a direction to increase the circulation amount of the cooling water in the condenser 25.
[0072]
When the liquid level of the liquid refrigerant is detected by the second liquid level gauge 36, the adjustment is performed in a direction in which one or both of the first and second expansion valves 27 and 28 are opened. In addition, adjustment is made in a direction to reduce the circulation amount of the cooling water in the condenser 25.
[0073]
The supply amount of the liquid refrigerant to the preheater 19 changes microscopically by opening and closing the second expansion valve 28. However, since the evaporator of the chilled water preheating device in the compression system is a kind of accumulator, the refrigerant liquid tank By appropriately selecting the capacity between the two liquid level gauges at 26 (for example, to about 2% of the liquid refrigerant amount held by the evaporator 21), evaporation due to a microscopic change in the liquid refrigerant supply amount to the preheater 19 is performed. Temperature fluctuations are well within acceptable limits.
[0074]
By controlling the operation of the ice heat storage device in this manner, freezing of cold water in the cold water channel 62 can be prevented, the temperature of the cold water at the subcooler inlet is maintained at 0.5 ° C., and the temperature of the subcooler outlet is maintained. The temperature is maintained at -2 ° C, and ice water is generated by releasing the supercooled state. Regarding the stop of the preheating, it is desirable to stop the supply of the refrigerant to the preheater 19 and the supply of the cold water to the preheater 19 in order to prevent a rapid change in the temperature of the cold water.
[0075]
<Start-up operation>
Next, an operation state of the ice heat storage device at the time of starting will be described, and an embodiment of the ice heat storage method of the present invention will be described. Note that the description will be made on the assumption that the ice in the ice heat storage tank 9 is melted during the start-up operation.
[0076]
When the ice heat storage device is started, if the outlet temperature of the ice heat storage tank is 0.5 ° C. or more, the preheating operation is not performed. In order not to perform the preheating operation, the cold water preheating pump 17 is stopped, or the first expansion valve 27 is fully closed. When the first expansion valve 27 is fully closed, the amount of the refrigerant circulating in the chilled water preheating device 3 is secured by using the second expansion valve 28 as a fixed orifice (a fixed opening). The second expansion valve 28 may be controlled by detecting the liquid level of the liquid refrigerant in the refrigerant liquid tank 26 without using the second expansion valve 28 as a fixed orifice.
[0077]
In a state where the preheating of the chilled water by the chilled water preheating device 3 is not performed, the temperature of the chilled water is reduced by cooling by the supercooler 5, as shown in FIG. FIG. 2 shows the subcooler outlet temperature, the ice heat storage tank outlet temperature, and the subcooler inlet temperature. For the sake of simplicity, the following description is based on the supercooler outlet temperature when starting up the ice heat storage device. Will be described.
[0078]
When the supercooler outlet temperature reaches 0 to 0.5 ° C., that is, the cold water unstable temperature range, freezing of cold water in the supercooler 5 may occur. Therefore, the cold water is preheated by the cold water preheating device 3 until the supercooling outlet temperature becomes 0.5 ° C. By this operation, the temperature of the chilled water supplied to the subcooler 5 rises rapidly, and rises from 0 ° C. to 0.5 ° C., skipping the chilled water unstable temperature range. By this operation, the ice in the cold water is once melted and hardly freezes even when the temperature is lowered again.
[0079]
When the supercooler outlet temperature is raised to 0.5 ° C., the cooling of the cold water by the supercooler 5 is continued while the preheating by the cold water preheating device 3 is continued. The operation control in the chilled water preheating device 3 is performed by selecting an appropriate control method in the normal operation described above. This operation control is performed until the temperature of the cold water reaches 0 ° C. again.
[0080]
When the subcooler outlet temperature reaches −0.5 to 0 ° C., that is, the subcooling release insufficient temperature range, the subcooling release in the subcooling release tank 7 becomes insufficient, and the supercooling state gradually becomes in the ice water flow path 64. There is a possibility that the ice water flow path 64 freezes due to the release, or the inside of the heat transfer tube of the supercooler 5 freezes. Therefore, when the supercooler outlet temperature reaches 0 ° C. again, the preheating of the chilled water by the chilled water preheating device 3 is stopped. The stop of preheating in the cold water preheating device 3 is as described above. By this operation, the cooling of the chilled water by the subcooler 5 is performed without change while the preheating is eliminated, so that the temperature of the chilled water supplied to the subcooler 5 rapidly decreases, and the temperature of the subcooling release is insufficient. And the temperature drops from 0 ° C. to −0.5 ° C. By this operation, the supercooled cold water is cooled to a temperature sufficient to release the supercooling in the supercooling release tank 7, and the supercooling state is not released in the ice water flow path 64 due to insufficient subcooling release. Freezing of the water channel 64 is prevented.
[0081]
If the subcooler outlet temperature skips the subcooling release insufficient temperature zone, the chilled water may be cooled by the subcooler 5 while maintaining the condition, but when the subcooler inlet temperature reaches 0.5 ° C, the chilled water preheats. The preheating by the device 3 is performed again. By this operation, the inlet temperature of the supercooler rapidly rises to 1 ° C., and escapes from the chilled water unstable temperature range.
[0082]
When the supercooler inlet temperature reaches 1 ° C., the temperature of the cold water is lowered again while being preheated by the cold water preheating device 3. When the subcooler inlet temperature drops again to 0.5 ° C, normal operation is started so as to maintain 0.5 ° C. This operation prevents freezing of cold water in the cold water channel 62 up to the inlet of the supercooler 5.
[0083]
Since the temperature difference of the chilled water is constant according to the cooling capacity of the subcooler as shown in FIG. If possible, the temperature of the cold water at any position may be used, and the above-described start-up operation can be performed by detecting the outlet temperature of the ice heat storage tank.
[0084]
<Preheating priority operation>
In the case where the amount of sensible heat of the refrigerant is insufficient with respect to the amount of preheated chilled water even by the control in the normal operation described above, the first expansion valve 27 is adjusted in the opening direction, and the refrigerant liquid level in the refrigerant liquid tank 26 is set to the first level. The temperature is lowered below the level gauge 35, and a gaseous refrigerant is introduced into the preheater 19. A gaseous refrigerant that compensates for the sensible heat shortage of the liquid refrigerant enters the preheater 19 and can satisfy the chilled water preheating amount. Further, since the liquid level of the refrigerant liquid tank 26 is lower than the first liquid level gauge 35, the second expansion valve 28 is fully closed, and the liquid refrigerant flows to the evaporator 21 by bypassing the preheater 19. Therefore, the sensible heat of the liquid refrigerant can be preferentially utilized in the preheater 19.
[0085]
According to the present embodiment, since the ice heat storage device having the above-described configuration is configured, the amount of the liquid refrigerant in the preheater 19 can be freely controlled in the self-manufactured ice heat storage device, and the temperature of the cold water is excellently adjusted. And further energy saving of ice making can be achieved.
[0086]
According to the present embodiment, the preheating of the chilled water by the chilled water preheating device 3 is controlled so as to skip the chilled water unstable temperature range and the subcooling release insufficient temperature range in the chilled water cooling process. Freezing of the water flow path can be prevented. Further, since the icing of the ice water flow path due to the release of the supercooling in the ice water flow path is prevented, the efficiency of generating the ice water in the supercool release tank 7 is good.
[0087]
Further, in the present embodiment, since the first and second expansion valves 27 and 28 also serve as a liquid refrigerant flow rate adjustment and liquid refrigerant distribution means, the liquid refrigerant in the preheater 19 can be simplified with a simpler configuration. Suitable amounts can be controlled.
[0088]
【The invention's effect】
As can be understood from the above description, according to the present invention, the refrigerant amount control means for controlling the amount of the liquid refrigerant in the preheater so that the preheater is filled with the liquid refrigerant in the chilled water preheating device in the self-manufactured ice heat storage device Therefore, it is possible to freely control the amount of the refrigerant in the preheater, and to provide an ice heat storage device excellent in adjusting the temperature of the cold water. Further, according to the present invention, since the cold water is preheated by the liquid refrigerant generated by the condensation, the energy balance between the preheating of the cold water by the refrigerant and the cooling of the cold water by the brine is not wasted, and further energy saving of ice making is achieved. be able to.
[0089]
Further, according to the present invention, the refrigerant amount control means distributes the condensed refrigerant to the preheater and the refrigerant bypass flow passage, which connects the flow paths on the upstream side and the downstream side with respect to the preheater. The configuration having the refrigerant distribution means is more effective in freely controlling the amount of the liquid refrigerant.
[0090]
Further, according to the present invention, the refrigerant amount adjusting unit detects the refrigerant liquid tank provided above the preheater and storing the refrigerant condensed by the condenser, and the liquid level of the refrigerant stored in the refrigerant liquid tank. The configuration having the level detecting means is more effective in freely controlling the amount of the liquid refrigerant.
[0091]
Further, according to the present invention, a chilled water bypass passage connecting the flow passage downstream of the ice heat storage tank and the flow passage upstream of the supercooler, and the temperature of the chilled water detected by the temperature detecting means, and the detection result is obtained. And a chilled water distributing means for distributing chilled water to the chilled water bypass passage based on the chilled water preheating device, the amount of chilled water supplied to the preheater is freely controlled to prevent excessive preheating of the chilled water. It is even more effective.
[0092]
Further, according to the present invention, the refrigerant amount control means is configured to control the amount of the liquid refrigerant in the preheater so that the gaseous refrigerant is introduced into the preheater when the sensible heat in the liquid refrigerant is insufficient. Also, it is possible to cope with freezing of cold water due to insufficient preheating.
[0093]
Further, according to the present invention, the temperature of the chilled water supplied from the ice heat storage tank that stores water and ice is adjusted by the chilled water preheating device, and the chilled water whose temperature has been adjusted is cooled to a supercooled state by the supercooler and cooled. In the ice heat storage method of generating ice by releasing the supercooled state of the cold water, the temperature of the cold water is detected by the temperature detecting means, and the temperature of the cold water before the supercooling is released is insufficient during the preheating by the cold water preheating device. When the temperature reaches the temperature range (more specifically, -0.5 to 0 ° C), the preheating of the chilled water by the chilled water preheating device is stopped until the temperature of the chilled water falls out of the undercooling release insufficient temperature range by cooling by the subcooler. Then, by controlling the preheating of the chilled water by the chilled water preheating device, it is possible to prevent icing in the ice water flow path due to insufficient subcooling, and to further improve the efficiency of ice water generation.
[0094]
According to the present invention, when the temperature of the chilled water before the supercooling is released falls to the chilled water unstable temperature range (more specifically, 0 to 0.5 ° C.) without being preheated by the chilled water preheating device, the chilled water is cooled. Preheating the chilled water by the chilled water preheating device until the temperature of the chilled water comes out of the chilled water unstable temperature range by cooling by the subcooler is more effective in preventing the icing of the chilled water in the ice water slurry conveying pipe or the subcooler. is there.
[0095]
Further, according to the present invention, in performing the above-described ice heat storage method, using the above-described ice heat storage device is more effective in performing more excellent ice making more economically.
[Brief description of the drawings]
FIG. 1 is a diagram showing an ice heat storage device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a temperature change of cold water by an ice heat storage method according to one embodiment of the present invention.
[Explanation of symbols]
1 Ice heat storage device
3 Cold water preheating device
5 Subcooler
7 Subcooling release tank
9 Ice thermal storage tank
11 Cooling tower
13 Ice
15 cold water
17 Cold water preheating pump (cold water distribution means)
18 Cold water circulation pump (cold water distribution means)
19 Preheater
21 Evaporator
23 compressor
25 Condenser
26 Refrigerant liquid tank
27 First expansion valve (pressure reducing device)
28 Second expansion valve (pressure reducing device)
30 brine circulation pump
33 Cooling water circulation pump
35 First level gauge (level detection means)
36 Second level gauge (level detection means)
37 First thermometer (temperature detecting means)
38 Second thermometer (temperature detecting means)
39 Third thermometer
61 Refrigerant channel
62 Cold water channel
63 brine flow path
64 Ice water channel
65 Cooling water channel
66 Refrigerant bypass channel
67 Cold water bypass channel

Claims (10)

A supercooler for cooling water to a supercooled state, an ice heat storage tank for storing ice and water generated by releasing the supercooled water from the supercooled state, and cold water supplied from the ice heat storage tank to the supercooler A cold water preheating device that adjusts the temperature of the ice heat storage device having a temperature detection unit that detects the temperature of the cold water,
The chilled water preheating device is a preheater that contains a refrigerant and exchanges heat between the refrigerant and the chilled water, a decompression device that expands the refrigerant to reduce the pressure of the refrigerant, and an evaporator that evaporates the depressurized refrigerant. A compressor that compresses a refrigerant in a vapor state, a condenser that condenses the compressed refrigerant to generate a refrigerant contained in a preheater, and a liquid refrigerant in the preheater such that the preheater is filled with a liquid refrigerant. Refrigerant amount control means for controlling the amount of
The said supercooler cools the said cold water to a supercooled state with the brine cooled by the said evaporator, The ice heat storage apparatus characterized by the above-mentioned. The refrigerant amount control means, a refrigerant bypass flow path that connects the upstream and downstream flow paths than the preheater, a refrigerant distribution means that distributes the condensed refrigerant to the preheater and the refrigerant bypass flow path, The ice heat storage device according to claim 1, comprising: The refrigerant amount control means is provided above the preheater, a refrigerant liquid tank for storing the refrigerant condensed in the condenser, and a level detection means for detecting the liquid level of the refrigerant stored in the refrigerant liquid tank The ice heat storage device according to claim 1, further comprising: A chilled water bypass passage connecting a flow passage downstream of the ice heat storage tank and a flow passage upstream of the subcooler, and detecting the temperature of the chilled water by a temperature detecting means, The ice heat storage device according to any one of claims 1 to 3, further comprising: a preheating device and cold water distribution means for distributing cold water to the cold water bypass flow path. 2. The refrigerant amount control means controls the amount of the liquid refrigerant in the preheater such that the gaseous refrigerant is introduced into the preheater when the sensible heat in the liquid refrigerant is insufficient. The ice heat storage device according to any one of claims 1 to 4. The temperature of the chilled water supplied from the ice heat storage tank that stores water and ice is adjusted by the chilled water preheating device, the chilled water whose temperature has been adjusted is cooled to a supercooled state by a supercooler, and the supercooled state of the cooled chilled water is released. In the ice heat storage method of producing ice by performing
The temperature of the chilled water is detected by the temperature detecting means, and the temperature of the chilled water is supercooled by cooling by the subcooler when the temperature of the chilled water before the release of the supercooling reaches the undercooling release insufficient temperature range during preheating by the chilled water preheating device. An ice heat storage method, wherein the preheating of the chilled water by the chilled water preheating device is stopped until the temperature of the chilled water is removed from the under-release temperature range. The ice heat storage method according to claim 6, wherein the subcooling release insufficient temperature range is -0.5 to 0C. If the temperature of the chilled water before the supercooling is released falls to the chilled water unstable temperature range without being preheated by the chilled water preheating device, the chilled water is preheated until the temperature of the chilled water leaves the chilled water unstable temperature range by cooling by the supercooler. The ice heat storage method according to claim 6, wherein the cold water is preheated by the device. The ice heat storage method according to claim 8, wherein the cold water unstable temperature range is 0 to 0.5C. The ice heat storage method according to any one of claims 6 to 9, wherein the ice heat storage device according to any one of claims 1 to 5 is used.

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