JPH0646127B2 - Supercooled ice heat storage device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ice storage device for an air conditioning system and an industrial cooling system by an ice storage tank using supercooled water.

(Prior Art) A conventional ice heat storage device used in an air conditioning system or the like is
A method is used in which the ice-making coil is filled in the tank, and a refrigerant such as a refrigerant or ethylene glycol is circulated in the coil to accumulate ice on the coil surface to store heat. , The refrigerant evaporation temperature must be lowered as the ice grows, and the efficiency of the refrigerator decreases. B) Since the ice making thickness is limited, it is not possible to make ice in the entire tank and the tank cannot be made compact c) In the tank However, there is a problem that due to natural convection, a water bypass occurs and the temperature of the extracted cold water rises before the ice is completely thawed.

Therefore, an attempt has been proposed to cool the ice to 0 ° C. or lower to produce water in a supercooled state, and use this to increase the ice making rate. The stationary method is the most common method for producing conventional supercooled water. This is a method of slowly cooling the water to a supercooled state while keeping it still stationary. A) The cooling efficiency is low because heat transfer to water is only natural convection. B) The supercooled state is unstable. Therefore, a slight stimulus such as vibration will break the supercooled state. C) Once frozen, the ice and water will coexist, and even if cooling is continued, the ice will only grow from the heat transfer surface and will no longer be overheated. There are problems such as not reaching the cooling temperature.

In JP-A-54-102648, a dilute aqueous solution to which a freezing point depressant is added is filled in an ice making container equipped with a cooling device and a stirrer, and the mixture is cooled to a supercooled state while stirring, and then the stirring is interrupted. Although a method of producing a large number of flake ices in an aqueous solution has been proposed, it is intended to combine the action of a freezing point depressant and the stirring action to reach a supercooled state in the entire container. However, there is a drawback in that the adverse effect of the mixture of Further, since the periphery of the stirring blade is frozen, the operation is intermittent and the efficiency is lowered.

Japanese Utility Model Laid-Open No. 54-102747 discloses a double-tube heat exchanger.

(Problem to be Solved by the Invention) An object of the present invention is to provide an ice heat storage device capable of freezing supercooled water by an efficient method, having a high refrigerator operation efficiency, and a high ice making rate. .

(Means for Solving the Problems) The above-mentioned object of the present invention comprises an outer structure for flowing a refrigerant or brine cooled by a refrigerator and an inner structure for flowing water, and the refrigerant or brine is kept at 0 ° C. or lower. A subcooled water manufacturing heat exchanger that keeps water at 0 ° C. to cool the water to bring the water temperature at the outlet of the inner structure to 0 ° C. or less;
A supercooled water discharge pipe that guides and discharges supercooled water from the outlet of the heat exchanger to the upper part of the ice storage tank, and water from the vicinity of the bottom of the ice storage tank of the inner structure of the heat exchanger. A return pipe guiding to the inlet, a water circulation pump arranged in the middle of the return pipe, a piping system for circulating a refrigerant or brine to the outside structure of the refrigerator and the heat exchanger, and an air conditioner and other loads And a chilled water circulation circuit including a chilled water pump, the chilled water circulation circuit communicating with the chilled water circulation circuit so that the chilled water can be supplied from near the bottom of the ice storage tank. .

(Operation) With this configuration, the cold water around 0 ° C drawn out from the ice storage tank by the water circulation pump is cooled to about -3 ° C in the heat exchanger to become supercooled water, which is transferred to the upper portion of the ice storage tank and discharged. However, at that time, it is frozen due to the impact of the fall. Thus, the sensible heat of the supercooled water is stored in place of the latent heat of ice. According to such an icing method, the ice making rate is increased as compared with the conventional ice heat storage device, the efficiency of the refrigerator is increased, and the entire system can be made compact.

Other features and advantages of the present invention will be apparent from the following description with reference to the embodiments of the accompanying drawings.

(Embodiment) FIG. 1 and FIG. 2 are system diagrams of a supercooling type ice heat storage device according to a preferred embodiment of the present invention during midnight ice making (FIG. 1) and during daytime operation (FIG. 2). . This system as a whole is composed of a supercooled water production section, an ice storage section, and a heat load section. The supercooled water production unit is a double-tube heat exchanger 1 including an outer coil 11 for flowing brine cooled by the refrigerator 10 such as ethylene glycol and an inner coil 12 for flowing water.
3, a brine circulation pump 14 and a control valve 15 are included. The ice storage unit includes an ice storage tank 20 having a heat insulating wall and a heat exchanger 1.
3, a supercooled water discharge pipe 21 for transferring and discharging supercooled water from the outlet of the ice storage tank to the upper part of the ice storage tank, a return pipe 22 for transferring water from near the bottom of the ice storage tank to the inlet of the heat exchanger, and It includes a water circulation pump 23 on the way. If necessary, a rotary rake device 40 for controlling a frozen state is provided on the top of the ice storage tank.
A drive motor 41 and a water tray 42 are attached. A strainer 24 (for example, 100 mesh or more) for separating ice nuclei and cold water is preferably attached to the lower part of the ice storage tank. The heat load unit includes a load of the air conditioner 30 and other components, a chilled water pump 31, and a control valve 32.

At the time of ice making at midnight shown in FIG. 1, the refrigerator 10 is operated to lower the temperature of the brine to −6 ° C. and send it into the heat exchanger 13. On the other hand, 0 ℃ pulled out from the bottom of the ice storage tank 20
Water in the vicinity is cooled by brine in the heat exchanger,
It becomes supercooled water of 3 ° C, is transferred to the upper part of the ice storage tank, and is dropped from the discharge pipe 21. Due to the impact of falling, the supercooled water freezes to form a sherbet. By continuing the operation of the refrigerator 10 and the pumps 14 and 23, sherbet-like ice is accumulated in the ice storage tank, and the ice making rate is increased to 60% or more. Further, unlike the conventional ice heat storage device, the surface of the heat transfer coil is not iced, so that it is not necessary to lower the refrigerant evaporation temperature of the refrigerator, and the refrigerator can always be operated with a constant high coefficient of performance.

During the daytime operation (at the time of thawing ice) shown in FIG. 2, the ice storage tank 20
The water near 0 ° C drawn from the bottom of the air conditioner is sent to the air conditioner 30 and other loads. Since the inside of the tank is ice-made evenly, it is possible to take out cold water at a constant temperature until the end of the ice disappearance. If there is sufficient ice in the ice storage tank, refrigerator 1
0 is stopped, and assuming that the inlet water temperature of the air conditioner is 7 ° C and the outlet water temperature is 12 ° C, the secondary side return water after passing through the inside of the heat exchanger 13 is at a temperature of 12 ° C and is above the ice storage tank. Be dropped from. At this time, if water is sprinkled through the internal passage of the rotary rake device 40, the ice in the ice storage tank can be uniformly melted. If the amount of ice in the ice storage tank is not sufficient for the load, operate the refrigerator even during the day, cool the secondary side return water to about 9 ° C in the heat exchanger, and then from the top of the ice storage tank. Let it fall. The refrigerator 10 can be used for cold water production operation in the daytime, and the brine temperature at the heat exchanger inlet can be set to 3 ° C. and the outlet temperature can be set to about 6 ° C., and the evaporation temperature becomes high, resulting in high efficiency operation. It is possible.

3 and 4 show a preferred example of a heat exchanger for producing supercooled water in the ice heat storage device of the present invention. FIG. 3 is a double tube heat exchanger, and FIG. A shell-and-tube heat exchanger is shown.

In order to stably produce supercooled water without freezing on the heat transfer surface, a) the heat transfer surface has a smoothness equal to or higher than that of the extruded copper tube. B) In the heat transfer part, heat transfer tubes are connected to each other. Connections other than heat transfer are not performed at all, and connections are required. C) The connection must have a structure that makes it difficult for local eddy current regions to occur due to stagnant or uneven flow of water.

The heat exchanger 13 shown in Fig. 3 is made of a bent tube in which the ends of a plurality of rows of tubes in which the inner structure 12 is parallel are formed in an arc shape, and the outer structure 11 surrounds the outer circumference of the bent tube. It is made of a coiled hollow body. Inner tube 12 is made of extruded copper tubing and its inner surface is smooth. The connecting portions 51 and 52 of the inner tubes do not exist in the heat transfer portion 50 (the central portion excluding the end portions) with the outer structure, but are provided at positions apart from the heat transfer portion. The connecting portions 51 and 52 are formed in a smooth flow path shape as shown in the enlarged portions A and B. That is, in A, the end surface of the inner tube is cut into a taper surface of 45 degrees or less, the distance between the end surfaces is set to be larger than 1/2 times the inner diameter D, and the sleeve 55 is fitted on the outer side. In B, the sleeve 56 is fitted inside the inner tube, both ends of the sleeve 56 are cut into tapered surfaces of 45 degrees or less, and the length of the inner parallel portion of the sleeve 56 is set to be larger than 1/2 times the inner diameter D. There is. The inner tube 12 and the sleeves 55 and 56 are welded by brazing or the like.

The heat exchanger 60 shown in FIG. 4 is similar to the heat exchanger 13 of FIG. 3 except that the outer structure 11 is made of a shell-shaped hollow body, and the inside is staggered. It is a structure. The connecting portion 53 of the tube is formed like the enlarged portion A or B in FIG.

Thus, by using the heat exchanger shown in FIGS. 3 and 4,
Supercooled water can be stably produced without freezing on the heat transfer surface.

FIG. 5 is a diagram showing the operation of the rotary rake device 40 attached to the upper portion of the ice storage tank 20. During the midnight ice making shown in FIG. 1, supercooled water is introduced from the direction of arrow E and dropped from the discharge pipe 21, but the discharge pipe 21 is set in the R direction by a horizontal swing mechanism (not shown). Therefore, the supercooled water does not enter the central water tray 42 and directly drops to the liquid surface in the tank. During the daytime operation shown in FIG. 2, the discharge pipe 21 is set in the L direction by the horizontal swing mechanism, and the secondary side return water at 9 ° C. is the central water pan 42.
After entering, it passes through the internal passage of the rotor 43,
Water is sprinkled on the surface of the tank. The rotor 43 is formed in the shape of a scraping blade (blade) in which a slanted plate piece is joined to a tubular member. Water circulation pump 2 in the direction of arrow F
3 is arranged, and a cold water pump 31 is arranged in the direction of arrow G to transfer the cold water passing through the strainer 24 in a predetermined direction.

The rotary rake device 40 can control the frozen state as follows.

a) The ice that has grown in a protruding shape at the falling portion of the supercooled water is cut horizontally to make the surface flat.

b) Disperse the resulting ice evenly in the bath.

c) Sherbet-like ice is continuously compressed to increase the ice making rate.

d) A torque detecting element is provided in the middle of the rotating shaft to detect the end of ice storage from the increase of the rotating torque and stop the refrigerator.

e) At the time of thawing, the secondary side return water is sprinkled over the entire water through the water sprinkling holes to perform uniform thawing.

The ice heat storage method (when using a rake) according to the present invention is compared with the conventional method as follows.

(Effects of the Invention) As described in detail above, according to the supercooling type ice heat storage device of the present invention, the following advantages can be obtained.

1) Since the heat transfer surface is not iced, the refrigerator can always be operated with a constant high coefficient of performance without lowering the refrigerant evaporation temperature.

2) On the heat transfer surface, since water is in a fluid state, the heat transfer efficiency is very good and the cooling time can be greatly shortened.

3) Supercooled water made in a fluid state is less likely to freeze than water made by the static method, so it is possible to transfer it.
Ice can be made in the heat storage tank.

4) The ice making rate can be increased from the conventional 40% or less to 60% or more, and the heat storage tank becomes compact.

5) Since ice can be made uniformly in the heat storage tank, it is possible to take out cold water at a constant temperature until the end of the ice disappearance when the ice is thawed.

[Brief description of drawings]

FIG. 1 is a system diagram showing an ice heat storage device of the present invention according to an embodiment in which brine is used, when making ice, FIG. 2 is a system diagram showing when cold water is produced, and FIG. 3 is heat for producing supercooled water. FIG. 4 is a vertical sectional view of a double-tube heat exchanger used as an exchanger, FIG. 4 is a vertical sectional view of a shell-and-tube heat exchanger, and FIG. 5 is a partially cutaway perspective view of a heat storage tank. 10 ... Refrigerator, 11 ... Outer structure 12 ... Inner structure, 13 ... Heat exchanger 14 ... Brine pump, 20 ... Ice storage tank 21 ... Discharge pipe, 22 ... Return pipe 23 ... … Water circulation pump, 24 …… Strainer 30 …… Air conditioner, 31 …… Cold water pump 40 …… Rotary rake, 50 …… Heat transfer part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Aoki 2-4, Yotsuya, Shinjuku-ku, Tokyo Within Shinryo Corporation (56) References JP-A-61-165533 (JP, A) 54-102747 (JP, U)

Claims (2)

[Claims] 1. An outer structure for flowing a refrigerant or brine cooled by a refrigerator and an inner structure for flowing water, wherein the refrigerant or brine is kept at 0 ° C. or lower to cool the water to cool the inner structure. A supercooled water manufacturing heat exchanger that keeps the water temperature at the outlet below 0 ° C., an ice storage tank having heat insulating properties, and supercooled water from the outlet of the heat exchanger is guided to the upper part of the ice storage tank. A supercooled water discharge pipe for discharging, a return pipe for guiding water from near the bottom of the ice storage tank to the inlet of the inner structure of the heat exchanger, a water circulation pump arranged in the middle of the return pipe, and a refrigerant. Or a cold water circulation circuit including a piping system that circulates brine to the outside structure of the refrigerator and the heat exchanger, an air conditioner and other loads, and a cold water pump, and cool water from near the bottom of the ice storage tank. Cold water circulation circuit communicating so that it can be supplied Supercooling type ice thermal storage apparatus comprising: a. 2. The device according to claim 1, wherein a strainer for separating ice nuclei and cold water is provided in a lower portion of the ice storage tank.