JPH0297834A - Super cooling type ice heat accumulation system - Google Patents

Abstract

PURPOSE:To improve a coefficient of performance and an ice filling rate of a refrigerating system by supercooling a specific water to be cooled by a refrigerant cooled by a refrigerator, dropping the degree of said supercooling at slow speed, generating ice slurry, and using said ice slurry for the purpose of cooling load. CONSTITUTION:The refrigerant cooled by a refrigerator 2 during ice making at night is fed into a heat exchanger 1 where the refrigerant turns into supercooling state water to be cooled running in a coil tube. Then, it is supplied a little by a little from a tip 8a of a feed pipe 8 with an supercooling cancellation device 6, then a supercooling water drop surface 33 is lowered so that the water may be frozen in contact with an electron cooling unit 32 which is preset as a cooling state. As a result, a sherbet-like ice slurry S is generated based on the frozen ice as a seed ice. The ice slurry S drops from a tip section 34a into an ice accumulator 7 without impact through its wall surface and stored there. In daytime, a refrigerator 2 suspends its operation and cooling water is fed into cooling load 11 from the ice accumulator 7. By way of a return pipe 13, the cooling water is sprayed into the ice accumulator 7 from a shower device 14 so that the ice slurry may be thawed. The water to be cooled is produced by a 0.3 to 1.5wt% solution of polyvinyl pyrrolidone whose molecular weight of 10,000 or over and which is a viscosity increasing material and solved by pure water.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a supercooling ice heat storage system used for cooling loads such as air conditioners.

(Prior Art) In recent years, various ice heat storage systems have been proposed as an alternative to conventional water heat storage systems.

The ice heat storage system aims to save energy by using nighttime electricity to store thermal energy for air conditioning during the day. Because it uses heat, compared to conventional water heat storage systems that only use temperature changes in water, the heat storage capacity per volume can be dramatically increased. It becomes possible to significantly downsize the space.

Current ice heat storage systems are divided into two types, depending on the properties of the ice produced: the so-called solid ice system, which uses solid water, and the so-called liquid ice system, which uses fluid granular (crystalline) ice. It is broadly divided into

Here, the liquid ice method includes a method in which an aqueous solution such as ethylene glycol is used and water in the solution is frozen, and a method in which supercooled water is frozen to generate an ice slurry.

(Problem to be Solved by the Invention) However, in the former method, the concentration of the remaining solution reaches an upper limit as the ice precipitates, so there is a problem that the operation is forced to freeze highly concentrated antifreeze over time. be.

Therefore, as a result, the coefficient of performance of the refrigeration system decreases, and there is also a limit to the water filling rate.

In addition, granular ice has advantages in terms of responsiveness during load demands and ease of handling, but the antifreeze used is expensive, and it is difficult to control water quality when no antifreeze is added. There are some problems.

On the other hand, in the latter method, freezing easily occurs in the heat exchanger that produces supercooled water, and it is difficult to make the ice pieces made by freezing supercooled water into fine pieces, so the water filling rate is high. There were problems such as not being able to do so.

An object of the present invention is to provide a supercooled ice heat storage system that can solve the conventional problems.

(Means for Solving the Problems) In order to achieve the above object, a supercooled ice heat storage system according to the present invention includes a supercooled water production section, an ice storage section, and a cooling load section, The water 512 production section is equipped with a heat exchanger that flows refrigerant or brine cooled by a refrigerator to cool the water to be cooled and bring it into a supercooled state below 0 degrees Celsius, and the ice storage section is an ice storage tank; a feed pipe for feeding the supercooled water from the heat exchanger to the supercooling removal device;
1" equipped with a return pipe that returns the water to be cooled to the heat exchanger, +l
The water to be cooled in ri is characterized by dissolving 0.3 to 1.5'LfQ% of a polymer thickener, and the polymer thickener in 1. It is preferable to use the above polyvinylpyrrolidone.

In addition, in order to achieve the above [1], the heat exchanger is
It consists of a shell-shaped hollow body and a coil tube disposed within the shell-shaped hollow body, and the coil tube is disposed in a spiral shape without a straight part within the shell-shaped hollow body, Preferably, the refrigerant or brine is caused to flow into the body to cool the cooled water flowing in the coil tube, and to bring the water temperature at the outlet of the coil tube into a supercooled state of 0° C. or less,
Furthermore, the inner surface of the coil tube has smoothness,
The connection portion between the coil tubes.

It is preferable that the connecting portion is provided only on the outside of the shell-like hollow body, and that the connecting portion is formed in a smooth flow path shape in which water flowing inside the coil tube does not produce a local vortex region.

In addition, in order to achieve the above object, the supercooling elimination device is disposed at the upper part of the ice storage tank, and includes a supercooled water descending surface that allows the supercooled water to descend at a slow speed, and a supercooled water descending surface that allows the generated ice slurry to be transferred to the storage tank. The supercooling elimination tank includes an ice sending surface to be transferred to the ice tank, and an ice nucleation unit installed at a predetermined position on the supercooled water falling surface or the ice sending surface, and the feeding pipe It is preferable that the tip is opened close to the supercooled water descending surface and configured to feed +iiJ water to be cooled from the tip of the feed pipe to the supercooled water descending surface.

(Example) Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1 to 6 show one embodiment of the present invention, and the supercooled ice heat storage system according to this embodiment roughly includes a supercooled water production section and an ice storage section. , and a cooling load section.

As shown in FIG. 1, the supercooled water production section produces supercooled water! It is composed of a heat exchanger 1, a refrigerator 2, a brine circulation pump 3, a feed pipe 4, and a return pipe 5. is sent from the feed pipe 4 to the heat exchanger 1 to cool the water to be cooled, which will be described later, to a supercooled state below 0°C.

The ice storage section includes a supercooling elimination device 6, an ice storage Jfj7,
A feed pipe 8 that feeds supercooled water from the heat exchanger 1 to the supercooling elimination device 6, and a return pipe 9 that returns the water to be cooled from near the bottom of the ice storage M47 to the heat exchanger l. and a cooled water circulation pump lO.

The cooling load unit also includes a cooling load 11 such as an air conditioner, a feed pipe 12 that supplies cold water to the cooling load 11 from near the bottom of the ice storage tank 7, and a return water from the cooling load 11. It is composed of a return pipe 13 that sends the ice to the ice storage tank 7, a shower device 14 provided at the tip thereof, and a circulation pump 15.

Therefore, the water to be cooled according to this embodiment is pure water with 0.
It is a solution of 3-L, 5% by weight of a polymer thickener, and in this example, Molecule!
More than 1,000 polyvinylpyrrolidone is used.

Next, in this embodiment, the heat exchanger I is
The configuration is shown in the figure.

That is, the heat exchanger 1 includes a shell-shaped hollow body 20 and a coil tube 21 disposed within the shell-shaped hollow body 20. It is a so-called shell and coil tube type.

In this embodiment, the shell-shaped hollow body 20 includes cylindrical inner tubes 22 arranged concentrically as shown in FIGS. 2 and 3.
A closed space is defined by an outer tube 23 and a lid 24 and a lid 25 that close the upper and lower edges, and the coil tube 21 is disposed within the shell-shaped hollow body 20.

As shown in FIG. 2, the coil tube 21 is arranged in a spiral shape with no straight parts inside the shell-like hollow body 20, and as shown in FIG. 23 so that the entire outer peripheral surface of the tube can come into contact with the refrigerant or brine.

In addition, the inner surface of the coil tube 21 is made to have a smoothness equal to or higher than that of an extruded steel pipe, and the pink connecting portion of the coil tube 21 is provided only on the outside of the shell-shaped hollow body 20 described in +iiij. Connections at the heat exchange part within the shell-like hollow body 20 are eliminated.

Furthermore, as shown in FIG. 4(a) or FIG. 4(b), the connecting portion employs a plug-in type connecting means for connecting the tube 21 and the connecting tube 26, avoiding screw connection. The span E between the connecting end surfaces is set to be 172 or more of the inner diameter of the tube 21, and the connecting end surface in contact with the water to be cooled is formed into a tapered surface of 45 degrees or less.
The water to be cooled flowing inside the coil tube 21 is formed into a smooth flow path shape that does not generate local vortex regions.

Next, FIG. 6 shows the configuration of the supercooling eliminating device 6 according to the present embodiment, and the supercooling eliminating device 6 includes a supercooling eliminating tank 31 and an electronic cooling unit as an ice nucleation unit. It consists of 32.

In this embodiment, the supercooling elimination tank 31 has a rectangular tube shape with a bottom, and the opening portion faces the top of the ice storage tank 5.
It is located on 5.

In this embodiment, the supercooling elimination tank 31 has a portion corresponding to the bottom wall surface formed as a supercooled water descending surface 33, and a supercooled water descending surface 33 that is perpendicular to the lower end of the supercooled water descending surface 33 in this embodiment. The part corresponding to the side wall surface of the decomposition tank 31 is the ice sending surface 3
It is formed as 4.

In this embodiment, the 1n supercooled water descending surface 33 and the ice delivery surface 34, which are perpendicular to each other, are arranged to be inclined at an angle a with respect to the vertical plane and the horizontal plane, respectively.

That is, the ice sending surface 34 is formed so as to be inclined at an elevation angle a in the direction of its tip 34a.

The electronic cooling unit 32 is disposed at the base end of the ice delivery surface 34 in this embodiment.

The electronic cooling unit 32 utilizes the Bertier effect.
It is mainly composed of an electronic cooling element made of a combination of N-type and P-type semiconductors, and is arranged so that the contact point, such as a copper plate, which is cooled to a predetermined temperature when a current is passed, faces upward.

Further, the electronic cooling unit 32 is controlled by a temperature sensor (not shown) to turn the current ON and OFF, and maintains the temperature of the cooling side contact below the temperature of supercooled water, which will be described later. There is.

As shown in FIGS. 1 and 6, the feed pipe 8 transfers the supercooled water that has been cooled to 0° C. or lower (about 12° C. in this embodiment) in the heat exchanger 1 to remove the supercooled water. 4f131, and the tip 8a of the transfer pipe 8 is connected to the supercooled water descending surface 3.
It is opened close to 3.

Also, the ice storage #! A filter 40 is provided near the bottom of the container 7 to separate ice nuclei from cold water.

In this embodiment having such a configuration, as shown in FIGS. 1 and 2, during ice making at night, brine such as ethylene glycol, which has been cooled to about -6° C. by the refrigerator 2, is supplied by the pump 3. Inlet 27 of the upper part of the heat exchanger l via tube 4
The water to be cooled flowing in the coil tube 21 is cooled by flowing through the shell-shaped hollow body 20 by returning it to the refrigerator 2 from the lower outlet 28 via the return pipe 5, and cooling the water flowing in the coil tube 21. Water temperature at the exit of 21 = 3℃
Bring to a supercooled state of about 3°C.

The supercooled water is sent from the outlet 29 at the top of the main body of the heat exchanger 1 through the feed pipe 8 in the direction of the ice storage Wj7.

Here, as will be described later, the ice is frozen by the supercooling eliminating device 6, and is layered in the ice storage V17 as a sherbet-like ice slurry.

In addition, water to be cooled is circulated from the bottom of the ice storage tank 7 into the fill tube 21 from the inlet 30 at the bottom of the main body of the heat exchanger 1 via the return pipe 9 by the pump lO to achieve supercooling similar to the above. continue.

On the other hand, in the supercooling eliminating device 6, as shown in FIG. The supercooled water slowly descends in the direction of the arrow from the top of the descending surface 33, and by contacting the electronic cooling unit 32, which is preset to a cooling state of about -5°C, the phase transition of water is excited. The ice is frozen and the initial ice is made.

Thereafter, the supercooling elimination tank 3 is used as this ice crystal seed water.
The supercooled water that is successively supplied by descending down the supercooled water descending surface 33 in the ice cube 1 comes into contact with the seed water and is continuously produced as a sherbet-like ice slurry S.

Therefore, if the electronic cooling unit 32 is energized at the time of initial ice making to cool the ice to below the predetermined temperature, it may be de-energized thereafter, and when the temperature exceeds the predetermined temperature as detected by the temperature sensor. The power is automatically turned on again only when the

Thus, the ice slurry S generated first is gradually pressed by the ice slurry S generated later, and gradually rises on the ice delivery surface 34 toward the tip 34a. The ice storage tank 7 slowly descends along the wall surface of the ice storage tank 7 due to its own weight, without giving any impact.
Ice is stored inside.

In addition, since the ice feeder 34 is formed with a predetermined inclination angle a, the ice slurry S does not fall into the ice storage tank 7 in large quantities at once, but is gradually lowered into the ice storage tank 7 little by little. be able to.

Thereafter, as the ice slurry S continues to fall, ice is stored in the ice storage tank 7 until a predetermined filling rate is reached.

In this way, the sensible heat of the supercooled water is converted into latent heat of the ice slurry S, and the heat is stored in the ice storage tank at night.

On the other hand, during daytime operation (when ice is melting), the operation of the refrigerator 2 is stopped and the cooling water supplied from the bottom of the ice storage tank 7 is passed through the supply pipe 12 to the cooling load 11. The water that returns through the return pipe 13 is uniformly distributed from the shower device 14 into the ice storage tank 7, and the stored ice slurry S
The ice is gradually thawing.

The effects of this embodiment will be described below.

First, in this embodiment, as the water to be cooled that is circulated between the heat exchanger l and the ice storage tank 7, polyvinylpyrrolidone having a molecular weight of 10.000 or more, which is a polymeric thickener, is added to pure water. The thickener-added water has the property of being able to stably maintain a supercooled state without causing a drop in freezing point. .

Therefore, it is possible to effectively prevent the water to be cooled from freezing within the coil tubes 21 in the heat exchanger 1, which has been a problem in the past.

Further, when ice is made using the supercooling eliminating device 6 with the thickener-added water in a supercooled state, fine ice particles are turned into slurry, and sherbet-like wood chips are formed.

That is, compared to the above conventional example in which pure water is used, it is possible to reliably generate fine ice slurry S.

Therefore, by increasing the fluidity of ice, ice can be stored uniformly, and it can also be melted uniformly, making it possible to significantly improve the water filling factor (IPF). It is capable of continuous ice making.

Regarding the heat exchanger l, the coil tube 21
is arranged in a spiral shape without a straight line in the shell-like hollow body 20, so a rotational flow toward the center of the tube is generated in the water to be cooled in the coil tube 21, as shown in FIG. Therefore, a laminar region does not occur as in the conventional example described above.

Therefore, the temperature of the water to be cooled is averaged at any part within the cross section of the tube 21, and there is no temperature gradient as in the conventional example. Freezing can be further reliably prevented.

Moreover, since the water to be cooled flows in the coil tube 21 while forming a rotational flow as described above, the water to be cooled is uniformly subjected to heat transfer through the tube wall.

Therefore, compared to conventional systems where only the water near the tube wall receives heat transfer, the heat exchange efficiency is significantly improved, and the heat exchanger itself can be made smaller. be.

Furthermore, the inner surface of the coil tube 21 is smooth, and the connecting portions of the coil tubes 21 are as follows:
The connection part is provided only on the outside of the shell-shaped hollow body 20, eliminating the connection at the heat exchange part, and the connection part has a smooth flow path shape in which the water flowing inside the coil tube 21 does not create a local vortex region. Therefore, supercooled water can be formed in a more stable state.

Next, regarding the supercooling elimination device 6, during initial ice making, the electronic cooling unit 32 forcibly eliminates the supercooling of the supercooled water and freezes it, and thereafter, the ice crystals are used as seed water to continuously form a sherbet. Since the ice slurry S is formed, supercooling can be completely eliminated and a high coefficient of performance (COP) can be obtained.

In addition, since the supercooled water is allowed to fall slowly along the supercooled water descending surface 33 and supercooling is eliminated in a flowing state as described above, it is compatible with the characteristics of the water to be cooled to which the thickener has been added. Due to the action, ice slurry S with smaller ice pieces and higher fluidity can be produced.

Furthermore, there is no need to separately provide a moving part as in the conventional example.

In addition, since the ice making method does not involve impacts such as drops or collisions during ice making, there is no stress concentration area that occurs in conventional methods, and there is no need for maintenance management such as reinforcing the structure and cleaning and inspecting moving parts. becomes.

Furthermore, as mentioned above, the energy required for initial ice making is only for the initial ice nucleation, and is only required in an extremely small amount.

In addition, in the above example, the molecule ffl was used as the polymer thickener.
Although an example using polyvinylpyrrolidone with a molecular weight of 10,000 or more has been shown, it is naturally possible to employ other suitable polymeric thickeners having the same or higher properties.

Regarding the supercooling eliminating device 6, the inclination angle a of the ice sending surface 34 may be set to an optimal angle depending on the flow rate of the supercooled water, but an inclination angle of about 5 to 10 degrees is sufficient. is preferred.

Furthermore, the inclination angle of the supercooled water descending surface 33 may be designed to be an optimal angle depending on the conditions, and it is of course free to set the inclination angle a different from the inclination angle a of the ice delivery surface 34.

Furthermore, the arrangement position of the electronic cooling unit 32 is not limited to the above-mentioned embodiment. For example, it may be installed on the supercooled water descending surface 33, and the supercooled water fed from the feed pipe 8 can be twisted from the tip 8a. The liquid may be brought into contact with the electronic cooling unit 32 little by little at a low flow rate.

In addition to the electronic cooling unit 32 described above, the ice nucleation unit may be one that utilizes ice nucleation active bacteria.

In ice-nucleating bacteria, the cells themselves become ice-crystal nuclei.

It is a bacterium that can freeze water at 3℃ to -2℃,
Bacterial name: Pseudomonas fluoresce
ns and Ee-winia aranas.

The ice-nucleating active bacteria can be immobilized on ceramic plates, glass peas, glass lattice plates, etc., so the plate-shaped unit on which the ice-nucleating active bacteria are immobilized can be removed from supercooling in accordance with the above-mentioned electronic cooling unit. By attaching it to a predetermined position in the tank 3M, it is possible to bring supercooled water into contact with it to form ice crystal nuclei during initial ice making, and to generate ice slurry S using this as seed water, in accordance with the above embodiment.

Furthermore, regarding the shape of the supercooling elimination tank 31.

The present invention is not limited to the above-mentioned embodiment, and the configuration of the supercooling eliminating device itself may be any suitable supercooling eliminating means other than the example using the above-mentioned supercooling eliminating tank 31.

Furthermore, it goes without saying that various modifications are possible without departing from the spirit of the present invention, such as the configuration of the ice storage tank 7 being able to be appropriately configured other than the above-described embodiments.

(Effects of the Invention) The present invention is configured as described above, and can achieve the following effects.

(1) Since the water to be cooled with a thickener added is used, a supercooled state can be stably maintained without causing a drop in the freezing point.
Freezing of the water to be cooled within the heat exchanger can be effectively prevented.

(2) By using cooled water with added thickener, it is possible to generate a fine ice slurry, and it is possible to significantly improve the water filling factor (IPF), allowing continuous ice making in a stable state. be able to.

Furthermore, by using the heat exchanger according to the present invention, the following effects can be achieved.

■Since the coil tube has a spiral shape, the temperature of the cooled water is averaged at any part of the tube cross section.
Freezing of water to be cooled can be reliably prevented.

(2) Because the water to be cooled is uniformly subjected to heat transfer through the tube wall due to the action of the zero-rotation flow, the heat exchange efficiency is significantly improved and the heat exchanger itself can be made smaller.

Furthermore, by using the supercooling eliminating device according to the present invention, the following effects can be achieved.

■The ice nucleation unit during initial production eliminates the supercooling of the supercooled water and freezes it, and from then on, the ice crystals are used as seed water to continuously form a sherbet-like ice slurry. Because of this, supercooling can be completely eliminated and a high coefficient of performance can be obtained.

■The supercooled water is allowed to fall slowly along the supercooled water falling surface, and supercooling is eliminated in a flowing state.
The wood chips are small and can produce highly fluid ice slurry.

(2) There is no need to separately provide a moving part as in the conventional example.

■Since the ice making method does not involve impact such as drops or collisions during ice making, there is no stress concentration area that occurs in conventional methods, and there is no need for maintenance management such as reinforcing the structure and cleaning and inspecting moving parts. becomes.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the present invention, FIG. 1 is a conceptual diagram showing an ice heat storage system according to this embodiment, and FIG. 2 is a conceptual diagram showing a heat exchanger according to this embodiment. , FIG. 3 is a sectional view taken along the line A-A in FIG. 2, FIGS.
FIG. 5(a) and FIG. 5(b) are explanatory diagrams each showing the state of the water to be cooled in the coil tube, and FIG. 6 is a conceptual diagram showing the supercooling elimination device according to this embodiment. 2... Refrigerator, l... Heat exchanger, 6... Supercooling elimination device, 7... Ice storage tank. 9... Return pipe, 11... Cooling load, 20... Shell-shaped hollow body, 21... Coil tube, 31... Supercooling elimination tank, 32... Ice nucleation unit (electronic cooling) unit), 3
3... Supercooled water falling surface, 34... Ice sending surface. 40... Filter S... Ice slurry a... Inclination angle. 8...Feed pipe, 10-...Circulation pump. 14... Shower device, patent applicant Toyo Engineering Co., Ltd. (1 other person) Figure 1

Claims (5)

[Claims] (1) Consisting of a supercooled water production section, an ice storage section, and a cooling load section, the supercooled water production section cools the water to be cooled by flowing refrigerant or brine cooled by a refrigerator. ,0
The ice storage unit includes a heat exchanger that brings the supercooled water to a temperature below ℃, and the ice storage section includes a supercooling elimination device, an ice storage tank, and a system for transferring the supercooled water from the heat exchanger to the supercooling elimination device. It is equipped with a feed pipe for supplying water and a return pipe for returning water to be cooled from near the bottom of the ice storage tank to the heat exchanger, and the water to be cooled has a temperature of 0.3 to
A supercooling type ice heat storage system characterized by having 1.5% by weight of a polymer thickener dissolved therein. (2) The supercooling ice heat storage system according to claim 1, wherein the polymer thickener is polyvinylpyrrolidone with a molecular weight of 10,000 or more. (3) The heat exchanger includes a shell-shaped hollow body and a coil tube disposed within the shell-shaped hollow body, and the coil tube is disposed in a spiral shape without a straight portion within the shell-shaped hollow body. The refrigerant or brine is made to flow in the shell-like hollow body to cool the cooled water flowing in the coil tube, and the water temperature at the outlet of the coil tube is supercooled to 0° C. or less. The supercooling type ice heat storage system according to claim 1 or 2, characterized in that the supercooling type ice heat storage system is in a state where: (4) The inner surface of the coil tube has smoothness, and the connecting portion between the coil tubes is provided only on the outside of the shell-shaped hollow body, and the connecting portion is connected to water flowing inside the coil tube. 4. The supercooling ice heat storage system according to claim 3, wherein the subcooling ice heat storage system is formed in a smooth flow path shape that does not cause local vortex regions. (5) The supercooling elimination device is disposed at the top of the ice storage tank, and includes a supercooled water descending surface that allows the supercooled water to descend at a slow speed, and an ice that moves the generated ice slurry to the ice storage tank. an ice nucleation unit installed at a predetermined position on the supercooled water descending surface or the ice discharging surface; The supercooling system according to any one of claims 1 to 4, wherein the supercooled water pipe has a distal end opened adjacent to the supercooled water pipe and is configured to feed the water to be cooled from the distal end of the feed pipe to the supercooled water descending surface. Cooling ice storage system.