JP2000329381A - Ice storage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ice storage system in which cold heat of water can be taken out efficiently while combining internal melting and external melting. SOLUTION: The ice storage system comprises a refrigerating machine 2 for cooling brine, a heat storage tank 3 incorporating heating tubes 8 for making ice with brine and melting the ice, brine piping 9 for circulating brine through the heating tubes 8 and the refrigerating machine 2, primary piping 16 for circulating water in the heat storage tank 3, as primary cooling water, through the outside of the heat storage tank, and a controller 23 for controlling the flow of brine and primary cooling water. The controller 23 begins circulation of primary cooling water through the primary piping 16 using the part around the heating tubes 8, melted by the brine in the heating tubes 8, as a water channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ice heat storage device. More specifically, for example, the present invention relates to an ice heat storage device for producing ice during the night when the electricity rate is low, and cooling the object to be cooled using the ice during the day.

[0002]

2. Description of the Related Art Heretofore, there has been known an ice heat storage device using a so-called static type ice heat storage tank. The static type ice heat storage tank has a heat transfer tube therein. Then, by flowing antifreeze (brine) through this heat transfer tube,
The water filled in the ice heat storage tank is cooled by a heat transfer tube and frozen. Then, the cold heat of the ice is also taken out by the brine flowing through the heat transfer tube, and the brine cooled in the ice heat storage tank cools the cooling target. This is because the ice is melted by the brine inside the heat transfer tube, and is hereinafter referred to as internal melting. Furthermore, cold heat may be extracted by directly circulating the water in the ice storage tank that has been thawed by the heat transfer tubes. Since this melts the ice around the heat transfer tube directly from the outside, it is hereinafter referred to as external melting.

According to the internal melting method, the ice on the outer peripheral side of the heat transfer tube is thawed as the cold heat is taken out, so that the heat transfer efficiency is reduced. However, since the passage of the brine as the medium for taking out the cold heat is always secured at the time of taking out the cold heat (inside the heat transfer tube), there is no limitation on the amount of ice making as in the external melting method described later, so that it is not necessary to enlarge the ice heat storage tank.

[0004] On the other hand, according to the external melting method, even as cold heat extraction proceeds, water as a cold extraction medium always comes into direct contact with ice, and since the contact area is larger than in the internal melting method, heat transfer efficiency does not decrease. However, since a water flow passage (hereinafter, referred to as a water channel) is required in the ice from the beginning of the operation, it is necessary to make ice so that the water channel is formed at the time of ice making. Need to be done.

[0005] Conventionally, an ice heat storage device using both the above-mentioned inner melting and outer melting has been known, but such a problem has not been solved. An ice heat storage device using both an internal melting method and an external melting method is disclosed in JP-A-10-238828 and Japanese Patent No. 267.
An apparatus disclosed in Japanese Patent Publication No. 9503 is known.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to efficiently take out cold heat by combining an internal melting method and an external melting method, and to use the produced ice in excess or deficiency. It is an object of the present invention to provide an ice heat storage device that can be used without any problem.

[0007]

The ice heat storage device of the present invention comprises:
Cooling means for cooling the brine, an ice heat storage tank provided with a heat transfer tube for making and melting ice by the brine, a brine pipe for circulating brine through the heat transfer tube and the cooling means, and ice heat storage. A primary cooling water pipe for circulating water in the tank as primary cooling water outside the ice heat storage tank, and a controller for controlling the flow of brine and the primary cooling water, the controller comprising: Sometimes, the circulation through the primary cooling water pipe is started when the ice around the heat transfer tube is thawed by the brine in the heat transfer tube.

[0008] Therefore, at the time when the melting of ice (internal melting) by the heat transfer tube has progressed to some extent, a water channel through which water flows in the ice heat storage tank is formed. Therefore, even if the circulation by the primary cooling water pipe starts, the water from the deicing can circulate in the ice heat storage tank and the primary cooling water pipe, so that the cold heat of the ice can be efficiently taken out.

The inlet of the primary cooling water pipe in the ice heat storage tank is disposed on one side in the longitudinal direction of the heat transfer tube, and the outlet is disposed on the other side. When the ice around the heat transfer tube is thawed by the brine, the circulation through the primary cooling water pipe is started so as to circulate the water through the thawed portion, so that the water passage by the internal melting is primarily cooled. It can be more suitably used for water circulation. The longitudinal direction of the heat transfer tube means, for example, when the heat transfer tube is curved in a zigzag manner, also includes the longitudinal direction of each straight line portion.

[0010] Another ice heat storage device of the present invention includes a cooling means for cooling brine, an ice heat storage tank provided with a heat transfer tube for ice making and de-icing by the brine, the heat transfer tube and the cooling means. Brine piping for circulating brine, primary cooling water piping for circulating water in the ice storage tank as primary cooling water outside the ice storage tank, and controlling the flow of brine and primary cooling water. And a controller for operating the refrigerator to cool the brine in the heat transfer tube at any time during thawing, and to keep the temperature difference between the brine at the inlet and the outlet of the heat transfer tube constant. Set to keep.

Therefore, even when the cold heat of the ice and the cold heat of the cooling means are taken out in parallel, the ice produced using energy can be used without any excess or shortage. In other words, in order to use the ice without excess or shortage, it becomes possible to supplement the insufficient cold heat by the cooling means.

Further, a heat exchanger is further provided in the above ice heat storage device, the brine pipe and the primary cooling water pipe are connected to the heat exchanger, and cooled by the brine and the primary cooling water. By connecting the secondary fluid pipe through which the secondary fluid circulates, and in the heat exchanger, the brine pipe and the primary cooling water pipe are arranged in series with each other to face the secondary fluid pipe, so that the secondary The fluid can be cooled.

Alternatively, if the brine pipe and the primary cooling water pipe are arranged in parallel with each other and opposed to the secondary fluid pipe, the flow path of the secondary fluid becomes plural and the flow path resistance is reduced. The energy consumption of the water supply driving means such as is reduced.

Further, the heat exchanger comprises a plate type heat exchanger, and has an area of a heat transfer surface between the secondary fluid and the brine and a heat transfer surface between the secondary fluid and the primary cooling water. By configuring so that the ratio can be changed, the cooling efficiency of the object to be cooled can be improved according to the operating conditions and the like.

Further, by providing a stirring means in the ice heat storage tank and instructing the controller to operate the stirring means at the time of ice making, the water in the ice heat storage tank is forcedly convected. Therefore, there is no large temperature gradient in the water. Therefore, since the cooling of the brine can be minimized, a decrease in the coefficient of performance of the cooling means can be prevented, and the whole water can be efficiently frozen.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ice heat storage device (hereinafter simply referred to as a heat storage device) of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a system diagram showing one embodiment of the heat storage device of the present invention.

A heat storage device 1 shown in FIG. 1 includes a refrigerator 2 as cooling means for cooling a primary refrigerant during ice making, an ice heat storage tank (hereinafter simply referred to as a heat storage tank) 3, and a secondary cooling apparatus for cooling an object to be cooled. And a heat exchanger 4 for transmitting cold heat to the refrigerant. Brine, which is an antifreeze, is used as the primary refrigerant, and water is used as the secondary refrigerant.

The refrigerator 2 is a known refrigerator having a compressor 5 for compressing the refrigerant therein, a condenser 6 for condensing the refrigerant, and an evaporator 7 for evaporating the refrigerant to release heat.

A heat transfer tube 8 is provided in the heat storage tank 3 and is filled with water for making ice. A brine pipe 9 for circulating brine is connected to the heat transfer tube 8, the evaporator 7 of the refrigerator 2, and the heat exchanger 4.
A brine pump 10 and a heat transfer tube 8
And a second bypass pipe 12 that bypasses the heat exchanger 4. A three-way valve 13 is provided at a connection point between the first bypass pipe 11 and the outlet of the heat transfer pipe 8. Symbol 14 in the brine pipe 9
a is a stop valve and 14b is a bypass valve.

A primary pipe 16 having a primary cooling water pump 15a and a flow control valve 15b is connected to the heat storage tank 3 so as to circulate through the heat exchanger 4 and return. Thermal storage tank 3
It circulates deicing water inside. The inlet 16a of the primary pipe 16 in the heat storage tank 3 is disposed at the lower end of each vertically extending heat transfer tube, and the outlet 16b is disposed at the upper end of each heat transfer tube. By doing so, when the primary cooling water pump 15 is operated, the water in the heat storage tank 3 flows along each heat transfer tube 8 as described later, and the heat transfer efficiency is improved. Further, a stirrer 21 is provided in the heat storage tank 3. As the stirrer 21, for example, a stirring blade, an aeration nozzle, or the like can be employed.

As shown in the figure, in the heat exchanger 4, the primary pipe 1 is connected to the secondary heat transfer section 18 of the secondary pipe 17 through which the secondary cooling water is circulated by the secondary cooling water pump 22.
6 and a brine heat transfer section 20 of the brine pipe 9 are connected in series. In the case of FIG. 1, the primary heat transfer portion 19 faces the upstream portion of the secondary heat transfer portion 18, and the brine heat transfer portion 20 faces the downstream portion of the secondary heat transfer portion 18. After the brine circulates through the heat exchanger 4, the brine first passes through the heat transfer tube 8 of the heat storage tank 3 and then reaches the refrigerator 2. Therefore, even if the remaining amount of ice is insufficient and the external cooling alone cannot maintain the predetermined temperature of the secondary cooling water, the refrigerator 2 can reliably maintain the predetermined temperature. It is suitable when the rise of the air conditioning temperature is not allowed (air conditioning for computers, air conditioning in hospitals, etc.).

Of course, as in the heat storage device 101 shown in FIG. 2, the flow direction of the brine is changed in FIG.
Can be reversed. Thereby, the brine is deprived of heat by the heat exchanger 4, reaches the refrigerator 2, and then passes through the heat transfer tube 8 of the heat storage tank 3. By doing so, during the chasing operation (the operation in which the refrigerator is also operated at the time of taking out the cold as described later), the cold can be taken out at a relatively high temperature by the refrigerator 2 (the brine temperature drop by the refrigerator can be reduced). Thus, the coefficient of performance of the refrigerator 2 is improved, and the operating cost is reduced. In FIG. 2, the primary heat transfer section 19 is opposed to the downstream side of the secondary heat transfer section 18, and the brine heat transfer section 20 is located on the upstream side of the secondary heat transfer section 18, contrary to FIG. 1. Facing each other. By doing so, since the primary cooling water temperature is lower than the brine temperature, the secondary cooling water can be cooled to a lower temperature by arranging in this way.

As shown in FIG. 3, the primary heat transfer section 1 of the primary pipe 16 is connected to the secondary heat transfer section 18 of the secondary pipe 17.
9 and the brine heat transfer section 20 of the brine pipe 9 may be connected in parallel. This heat exchanger is called a parallel heat exchanger 4a. The use of the series heat exchanger 4 improves the cooling effect of the secondary cooling water. On the other hand, if the parallel type heat exchanger 4a is used, a plurality of flow paths on the secondary cooling water side are provided, and flow path resistance is reduced, so that energy consumption of a water supply driving means such as a pump is reduced.

The heat storage device 1 includes pumps 10, 15, 2
2, a controller 23 is provided for controlling the operation timing and rotation speed, the opening degree of the three-way valve 13, and the adjustment of the opening degree when a flow control valve is installed.

The operation of the heat storage device 1 will be described with reference to FIG.

FIG. 4A shows a line during the ice making process. The stop valve 14a in the brine pipe 9 is closed to prevent the brine from reaching the heat exchanger 4, and the primary pipe 16 and the secondary pipe 17 are closed. Then, the brine cooled below the freezing point by the refrigerator 2 flows through the heat transfer tube 8 in the heat storage tank 3 to freeze water. In FIG. 4A, the pipe through which the fluid flows (the brine pipe 9) is shown by a solid line, and the pipe through which the fluid does not flow (a part of the brine pipe 9, the primary pipe 16 and the secondary pipe 17) is shown by a two-dot chain line. . When the water is frozen, the stirrer 2
1 is operated, or the primary cooling water pump 15a is operated to circulate the primary cooling water, whereby the water in the heat storage tank 3 is forcedly convected, so that a large temperature gradient does not occur in the water. Therefore, since the cooling of the brine can be minimized, a decrease in the coefficient of performance of the refrigerator can be prevented, and the whole water can be efficiently frozen.
Further, as described later, since it is not necessary to form a water channel for external melting, the whole water can be frozen. As a result, there is no need to increase the internal volume of the heat storage tank.

Next, FIG. 4 (b) shows a line in a step of extracting cold from ice and cooling the object to be cooled.
At this time, the stop valve 14a and the bypass valve 14b in the brine pipe 9 are opened to circulate the brine to the heat exchanger 4 and also to the heat transfer pipe 8. Secondary piping 1
7 circulates secondary cooling water. The refrigerator 2 is not operating because it is a step of extracting cold heat from ice. At the beginning of the operation, the primary cooling water is not circulated through the primary pipe 16.
Therefore, at first, only the internal melting by the heat transfer tube 8 is performed. Then, after a lapse of a predetermined time from the start of operation, or when the opening of the three-way valve 13 on the side of the first bypass pipe 11 approaches closing, the primary cooling water pump 15 is operated by an instruction of the controller 23 and the primary pipe 16 is connected to the primary cooling water pump 15. Circulate the primary cooling water. As described above, the controller 23 includes the amount of chilled heat taken out of the heat storage tank 3 by the brine (directly, the brine temperature after mixing of the three-way valve 13) and the amount of chilled heat taken out of the heat storage tank 3 by the primary cooling water. The amount (directly, the flow rate and temperature of the primary cooling water by the pump 15a or the flow control valve 15b) is set.

This is because the pre-investigation through tests and trial runs is based on the time required for the ice on the outer periphery of the heat transfer tube 8 to be melted by the internal melting and for that portion to form a suitable channel for external melting, or The amount of residual ice when the water channel is formed is determined and set in the controller 23. Further, as described above, the inlet 16a of the primary pipe 16 in the heat storage tank 3 is disposed at the lower end of each vertically extending heat transfer tube, and the outlet 16b is disposed at the upper end of each heat transfer tube. The flow of water in the heat storage tank 3 by the operation of the cooling water pump 15 effectively flows through the water channel outside the heat transfer tube 8. As a result, the heat transfer efficiency is improved and the external fusion is effectively performed. Furthermore, the heat transfer tube 8
As a result, the efficiency of the internal melting, that is, the extraction of cold heat by the brine in the heat transfer tube 8 is improved.

In the heat storage tank 3, the inlet 16a of the primary pipe 16 is disposed on the lower side, and the outlet 16b is disposed on the upper side, but the reverse is also possible. In addition, if the heat transfer tubes are arranged horizontally, the inlet 1
What is necessary is just to arrange | position the 6a and the exit part 16b in the position on either side. By doing so, the water in the heat storage tank 3 can flow along the water channel on the outer peripheral side of each heat transfer tube 8 in the same manner as described above.

With the above operation, the secondary pipe 17 through the heat exchanger 4 is connected by the brine pipe 9 and the primary pipe 16.
Transfers cold to secondary cooling water.

It is also possible to operate the refrigerator 2 (chasing operation) in this cold heat extraction step, thereby further cooling the brine. That is, the secondary cooling water is to be cooled by both the ice and the refrigerator 2. In this case, the control of the entire heat storage device 1 by the controller 23 is performed on the basis of taking out cold heat from ice,
Insufficient (estimated) cold energy is replenished by the refrigerator 2. That is, the first object is to use ice produced using electric energy without excess or deficiency.

Therefore, in the heat storage device 1 shown in FIG. 1, the controller 23 controls the three-way connection in the brine pipe 9 so that the temperature difference between the inlet point E and the outlet point S of the heat transfer pipe 8 in the brine pipe 9 becomes constant. The brine flow rate and the primary cooling water flow rate are controlled by controlling the valve 13 and a flow control valve (not shown), and controlling the primary cooling water pump 15a and the flow control valve 15b in the primary pipe 16. This is an example of the control of the controller 23.
And, all the fluctuations of the cold heat supply due to the temperature fluctuation of the secondary cooling water are performed by the refrigerator 2.

On the other hand, in the heat storage device 101 of FIG.
The temperature of the brine flowing into the refrigerator 2 fluctuates due to the temperature fluctuation of the secondary cooling water. On the other hand, the refrigerator 2 is set so that the brine temperature at the outlet is constant regardless of the brine temperature at the inlet. Therefore, the controller 23 keeps the inlet temperature to the heat exchanger 4 in the brine pipe 9 (the temperature at the downstream point of the walk valve 13 only) constant in order to keep the amount of cold heat extracted from the ice in the heat storage tank 3 constant. That is, the outlet of the refrigerator 2 and the heat exchanger 4
The brine pump 10, the three-way valve 13, and a flow control valve (not shown) are controlled so that the temperature difference between the inlet and the brine is constant. This is an example of the control of the controller 23. And, all the fluctuations of the cold heat supply due to the temperature fluctuation of the secondary cooling water are performed by the refrigerator 2.

Next, the type of the heat exchanger 4 is not limited, but it is preferable to use a known plate type heat exchanger. This is because, according to the plate type heat exchanger, it is possible to freely combine and use the serial type as shown in FIGS. 1 and 2 and the parallel type as shown in FIG.
Further, in both the serial type and the parallel type, the heat transfer area ratio between the primary heat transfer portion and the brine heat transfer portion can be easily changed.

FIG. 5 is a perspective view of a main part of the plate heat exchanger before assembly. The plate type heat exchanger has a plurality of heat transfer plates 31 stacked as shown in FIG.
1 for exchanging heat between fluids flowing through the following fluid chambers 34 on both sides. Some heat transfer plates 31b, 31c, 31
Three or less fluid passage holes 33 are formed in the d, 31e and end plate 32 at predetermined positions at any of the four corners. Fluid passage holes 33 are formed in the four corners of the other heat transfer plates 31a. In addition, each heat transfer plate 3
A gasket 35 is attached to 1 so as to define a fluid chamber 34 that communicates only with the fluid passage holes 33 at two corners on one side. The gasket 35 functions by being pressed against the adjacent heat transfer plate 31 to form the fluid chamber 34.
The heat transfer plates 31 and the end plates 32 are stacked such that the fluid chambers 34 are alternated as shown in the figure. The fluid passage hole 33
As the fluid passing through the fluid chamber 34, the secondary cooling water is indicated by a solid line, the primary cooling water is indicated by a broken line, and the brine is indicated by an alternate long and short dash line.

The secondary cooling water flows from the right end to the left end in the figure,
The secondary cooling water flows in from the right end and flows out again to the right end while exchanging heat with the secondary cooling water. The brine flows in from the left end of the drawing and flows out again to the left end while exchanging heat with the secondary cooling water. FIG.
In this manner, a series heat exchanger 4 in which the primary cooling water on the upstream side and the brine on the downstream side are exchanged in series with the secondary cooling water is shown.

In such a plate heat exchanger, by changing the positions of the fluid passage holes in the heat transfer plate and the end plate, and by changing the inlet and outlet of the fluid, the heat exchanger can be used in a parallel type. In addition, it can be understood that the heat transfer area ratio between the primary heat transfer section and the brine heat transfer section can be easily changed in both the serial type and the parallel type. Therefore, since piping is not required for a configuration change such as series or parallel, even if space is limited, the degree of freedom in installation is improved.

[0039]

According to the present invention, a water channel through which water flows (a water channel for external melting) is formed in the ice heat storage tank when the ice melting (internal melting) by the heat transfer tube has progressed to some extent. Therefore, even if the circulation by the primary cooling water pipe starts, the water from the deicing can circulate in the ice heat storage tank and the primary cooling water pipe, so that the cold heat of the ice can be efficiently taken out. This means that ice can be formed in the entire heat storage tank without considering a water channel for external melting when making ice. In other words, since the ice making rate is improved, the size of the heat storage tank can be reduced.

Further, even when the cold heat of the ice and the cold heat of the cooling means are taken out in parallel, the ice produced by using the energy can be used without excess or shortage. In other words, in order to use the ice without excess or shortage, it becomes possible to supplement the insufficient cold heat by the cooling means.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of an ice heat storage device of the present invention.

FIG. 2 is a system diagram showing another embodiment of the ice heat storage device of the present invention.

FIG. 3 is a system diagram showing another example of the heat exchanger in the ice heat storage device of the present invention.

4 is a system diagram showing the operation of the ice heat storage device of the present invention, wherein FIG. 4 (a) is for ice making and FIG. 4 (b) is for ice melting.

FIG. 5 is a perspective view showing an essential part of an example of a heat exchanger in the ice heat storage device of the present invention before assembly.

[Explanation of symbols]

 1, 101 ··· heat storage device 2 ··· refrigerator 3 ··· heat storage tank 4 ··· heat exchanger 4a ··· parallel heat exchanger 5 ··· compressor 6 · Condenser 7 ··· Evaporator 8 ··· Heat transfer tube 9 ··· Brine pipe 10 ··· Brine pump 11 ··· First bypass pipe 12 ··· Second bypass pipe 13 · · · · Three-way valve 14a · · · Stop valve 14b · · · Bypass valve 15a · · · Primary cooling water pump 15b · · · Flow control valve 16 · · · Primary piping 16a · · · Inlet 16b · · · Outlet section 17 Secondary pipe 18 Secondary heat transfer section 19 Primary heat transfer section 20 Brine heat transfer section 21 Stirrer 22 Next cooling water pump 23 Controller 31 Heat transfer plate 32 End plate 33 Fluid passage hole 34 ··· Fluid chamber 35 ··· Gasket E ··· Inlet point of (heat transfer tube) S ··· Outlet point of (heat transfer tube)

Claims (7)

[Claims] A cooling means for cooling the brine;
An ice heat storage tank provided with a heat transfer tube for making and deicing ice by the brine, a brine pipe for circulating brine through the heat transfer tube and cooling means, and ice in the ice heat storage tank as primary cooling water. A primary cooling water pipe for circulating outside the heat storage tank, and a controller for controlling a flow of the brine and the primary cooling water, wherein the controller operates around the heat transfer pipe by the brine in the heat transfer pipe at the time of melting ice. An ice heat storage device that starts circulation through the primary cooling water pipe when the ice is thawed. 2. An inlet for a primary cooling water pipe in the ice heat storage tank is disposed on one side in a longitudinal direction of the heat transfer tube, and an outlet is disposed on the other side. 2. The ice heat storage device according to claim 1, wherein when the ice around the heat transfer tube is thawed by the brine in the tube, circulation through the primary cooling water pipe is started so that water flows through the thawed portion. 3. Cooling means for cooling the brine,
An ice heat storage tank provided with a heat transfer tube for making and deicing ice by the brine, a brine pipe for circulating brine through the heat transfer tube and cooling means, and ice in the ice heat storage tank as primary cooling water. A primary cooling water pipe for circulating outside the heat storage tank, and a controller for controlling the flow of the brine and the primary cooling water, wherein the controller removes the brine in the heat transfer tube at any time during deicing. An ice heat storage device configured to operate a refrigerator for cooling and to maintain a constant temperature difference between brine at an inlet and an outlet of a heat transfer tube. 4. A heat exchanger is further provided, wherein the brine pipe and the primary cooling water pipe are connected to the heat exchanger, and a secondary fluid cooled by the brine and the primary cooling water is provided. A circulating secondary fluid pipe is connected, and in the heat exchanger, a brine pipe and a primary cooling water pipe are arranged in series with each other and opposed to the secondary fluid pipe. The ice heat storage device according to any one of the above items. 5. A heat exchanger is further provided, wherein the brine pipe and the primary cooling water pipe are connected to the heat exchanger, and a secondary fluid cooled by the brine and the primary cooling water is provided. A circulating secondary fluid pipe is connected, and in the heat exchanger, a brine pipe and a primary cooling water pipe are arranged in parallel with each other and opposed to the secondary fluid pipe. The ice heat storage device according to any one of the above items. 6. The heat exchanger according to claim 1, wherein the heat exchanger comprises a plate heat exchanger, wherein a heat transfer surface between the secondary fluid and the brine, and a heat transfer surface between the secondary fluid and the primary cooling water. 6. The apparatus according to claim 4, wherein the area ratio of the first and second parts is variable.
The ice heat storage device as described in the above. 7. The ice heat storage tank further includes a stirring means, and the controller instructs the stirring means to operate during ice making. Item 13. The ice heat storage device according to Item.