JP2006112652A - Ice making method and device for heat storage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ice making method and its device for heat storage capable of obtaining a heat storage medium of low temperature which can not be obtained by ice obtained by phase change of water, by changing a phase of an aqueous solution. <P>SOLUTION: The aqueous solution W is used as fluid for ice making, and a temperature T<SB>1</SB>of the aqueous solution W taken out from a heat storage tank 1 and introduced to an ice making heat exchanger 10 is controlled to be raised by a predetermined temperature α from an ice-liquid coexistence temperature Tk(=Tg) of the aqueous solution W in the heat storage tank 1, and a refrigerant or brine B guided to the ice making heat exchanger 10 is controlled to be lower than the ice/liquid coexistence temperature Tk(=Tg) by a prescribed temperature β by controlling a freezer 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat storage ice making method and apparatus for making an aqueous solution.

  In recent years, in order to average power demand day and night, attention has been focused on a cold storage system that stores cold energy using surplus power at night and extracts cold energy during the day and uses it for cooling loads and the like.

  There are cold water storage methods and ice storage methods that both use water for cold storage, but ice storage methods that can store heat more efficiently are used more frequently from the viewpoint of efficient use of equipment space. .

  There are two types of ice storage methods for heat storage: static method and dynamic method. The former is a method of icing and growing ice on the heat transfer surface of the ice-making heat exchanger, but the heat transfer efficiency decreases as the ice thickness increases. The latter includes a peeling method that intermittently peels off the ice that has landed on the heat transfer surface of the ice-making heat exchanger, and a supercritical water that creates supercooled water and releases the supercooled state to change the phase and generate ice. There is a cooling system. The supercooling method is attracting attention because of the advantage of ice generation efficiency.

  For example, as disclosed in Patent Documents 1 to 3 below, the supercooling method takes out the water stored in the heat storage tank, leads it to an ice making heat exchanger, and cools the refrigerant or brine (hereinafter, referred to as “cooling machine”). The water is cooled to a supercooled state below the freezing point temperature with an ice making heat exchanger. And when returning this water in a thermal storage tank, supercooling will be cancelled | released by the collision with the liquid level in a tank, a part will change into ice, and it will become sherbet-like ice.

  Since the heat storage medium obtained by this heat storage ice making method is ice obtained by changing the phase of water, it can only obtain a temperature of 0 ° C., but there is no problem when it is used for cooling such as building air conditioning.

  However, when used in fields other than air conditioning, for example, in fields related to foods and beverages such as alcoholic beverages, retort foods, and dairy products, a colder heat source may be required. Such a low-temperature cold heat source is difficult to obtain with water ice storage media.

  Therefore, the present inventors have focused on using an aqueous solution containing alcohol, sodium chloride, and the like as a heat storage medium. Such an aqueous solution has a freezing temperature of about −10 ° C. and can be used as a cold heat source in the field of food and beverages.

  However, the temperature in the case of freezing the aqueous solution varies depending not only on the type but also the concentration of each aqueous solution, and it is difficult to simply divert the ice storage method for heat storage to an aqueous solution. When water is phase-changed, the freezing point temperature of water is always constant at 0 ° C under atmospheric pressure, so if the temperature is raised (preheated) to a constant temperature of 0 ° C + α ° C and sent to an ice making heat exchanger, ice making There is no freezing in the heat exchanger, and supercooled water at about −2 ° C. is stably obtained. In addition, the brine for cooling the water is also kept at a constant temperature of 0 ° C.-β ° C. (= −3 ° C.) and sent to the ice making heat exchanger without the supercooling water solidifying in the ice making heat exchanger. Can be discharged.

  However, when the aqueous solution is cooled, first, only the water in the aqueous solution undergoes a phase change. For this reason, the aqueous solution is concentrated as the amount of ice is increased, and the freezing point of the aqueous solution is lowered. It is difficult to obtain a uniform and stable supercooled state.

Further, the viscosity of the aqueous solution increases due to the concentration of the aqueous solution and the lowering of the freezing point. The increase in viscosity occurs not only with aqueous solutions but also with brine. For this reason, when the aqueous solution is phase-changed by the heat storage ice making method, the case of water cannot be simply used.
Japanese Patent No. 2577156 (see claim 1 and FIG. 1) Japanese Patent No. 2911710 (see claim 1 and FIG. 1) Japanese Patent Laid-Open No. 7-83547 (see FIG. 1, abstract)

  An object of the present invention is to provide a heat storage ice making method and apparatus for stably obtaining a low-temperature heat storage medium that cannot be obtained by ice whose phase has been changed by changing the phase of an aqueous solution.

  The inventors of the present invention have achieved the above object by controlling the aqueous solution from both the lowering of the freezing point and the increase in viscosity, and have completed the present invention. As a countermeasure against the freezing point depression, if the freezing point temperature of the aqueous solution is Tg (° C.), the Tg (° C.) drops due to the concentration of the aqueous solution accompanying the amount of ice making. Must be controlled to Tg + α (° C.). For that purpose, it is necessary to grasp the freezing point temperature Tg (° C.) under a certain amount of ice making, but the temperature Tk (° C.) of the aqueous solution when the aqueous solution and ice coexist in the heat storage tank (hereinafter referred to as ice Focusing on the fact that the liquid coexistence temperature is abbreviated as Tk ° C), regardless of the ice making condition, it is exactly Tg (° C) and equal, and the aqueous solution is supplied to the ice making heat exchanger based on this ice liquid coexistence temperature Tk ° C. This is performed by controlling the temperature to be supplied and the temperature of the brine to be supplied to the ice making heat exchanger to be a predetermined set value.

  On the other hand, as a countermeasure against the increase in viscosity, the flow rate is controlled so that a constant circulation amount is secured in each of the aqueous solution and the brine.

  If such control is performed, the aqueous solution supercooled in the ice-making heat exchanger can be allowed to flow out of the ice-making heat exchanger in a stable liquid state without being solidified. Thus, low-temperature heat storage ice can be stably obtained.

  That is, the object of the present invention is achieved by the means described below.

(1) The ice making fluid from the inside of the heat storage tank and the brine cooled by the refrigerator are each led to an ice making heat exchanger to exchange heat, and the ice making fluid is cooled to a supercooled state to thereby store the heat. An ice making method for heat storage that returns to the inside of the tank and produces sherbet-shaped ice,
An aqueous solution is used as the ice-making fluid, and the temperature of the aqueous solution introduced into the ice-making heat exchanger is higher by a predetermined temperature than the ice liquid coexisting temperature of the aqueous solution in the heat storage tank. An ice making method for heat storage, wherein the temperature is controlled so that the temperature of the brine guided to the vessel is lower than the ice liquid coexistence temperature by a predetermined temperature, and the brine is introduced into the ice making heat exchanger.

(2) The ice making fluid from the heat storage tank and the brine cooled by the refrigerator are each led to an ice making heat exchanger to exchange heat, and the ice making fluid is cooled to a supercooled state to store the heat. An ice making method for heat storage that returns to the inside of the tank and produces sherbet-shaped ice,
When an aqueous solution is used as the ice-making fluid, and the flow rate of the aqueous solution guided from the heat storage tank to the ice-making heat exchanger becomes equal to or less than a predetermined flow rate due to a temperature drop and concentration increase due to the concentration of the aqueous solution, An ice making method for heat storage, characterized by returning to a predetermined flow rate.

(3) The ice making fluid from the inside of the heat storage tank and the brine cooled by the refrigerator are each led to an ice making heat exchanger to exchange heat, and the ice making fluid is cooled to a supercooled state to thereby store the heat. An ice making method for heat storage that returns to the inside of the tank and produces sherbet-shaped ice,
An aqueous solution is used as the ice making fluid, and when the flow rate of the brine introduced from the refrigerator to the ice making heat exchanger becomes a predetermined flow rate or less with a temperature drop, the flow rate control means returns the flow rate to the predetermined flow rate. Ice making method for heat storage.

  (4) The temperature at which the aqueous solution is made higher than the ice liquid coexistence temperature is 0.5 ° C. to 1.5 ° C., and the temperature at which the refrigerant is at a temperature lower than the ice liquid coexistence temperature is 3.5 ° C. to 4 ° C. (1) The ice storage method for heat storage according to (1) above, which is 5 ° C.

  (5) The ice making method for heat storage according to (1) to (4), wherein the aqueous solution is an alcohol aqueous solution.

  (6) The ice making method for heat storage according to (1) to (4), wherein the aqueous solution is a sodium chloride aqueous solution.

(7) a heat storage tank in which ice making fluid is stored;
A plate-type ice-making heat exchanger in which a flow path for refrigerant in which brine flows and a flow path for the ice-making fluid in which the ice-making fluid flows are formed between a plurality of opposed heat transfer plates;
An ice making fluid circulation circuit for circulating the ice making fluid between the heat storage tank and the ice making heat exchanger;
A refrigerant circulation circuit for guiding brine cooled by a refrigerator to the ice making heat exchanger;
Have
A heat storage ice making device for producing a sherbet-like ice by cooling the ice making fluid to a supercooled state by exchanging heat between the ice making fluid and the refrigerant in the ice making heat exchanger. ,
An aqueous solution is used as the ice making fluid, and an aqueous solution control unit that controls the temperature of the aqueous solution flowing into the ice making heat exchanger to be higher than the ice solution coexistence temperature by a predetermined temperature; and the temperature of the brine is the ice solution An ice making device for heat storage, comprising: a refrigerant temperature control unit that controls a temperature lower than the coexistence temperature by a predetermined temperature.

(8) a heat storage tank in which ice-making fluid is stored;
A plate-type ice making heat exchanger in which a refrigerant flow path through which brine flows and a flow path for ice making fluid through which the ice making fluid flows are alternately formed between a plurality of opposed heat transfer plates;
An ice making fluid circulation circuit in which the ice making fluid is circulated between the heat storage tank and the ice making heat exchanger;
A brine circulation circuit in which brine is circulated between a refrigerator and the ice making heat exchanger;
Have
A heat storage ice making device for producing a sherbet-like ice by cooling the ice making fluid to a supercooled state by exchanging heat between the ice making fluid and brine in the ice making heat exchanger,
Flow control using an aqueous solution as the ice-making fluid, and returning the flow rate of the aqueous solution circulating through the ice-making fluid circulation circuit to the predetermined flow rate when the flow rate of the aqueous solution decreases below a predetermined flow rate due to a temperature drop and concentration increase due to concentration. An ice making apparatus for heat storage, characterized by comprising means.

(9) a heat storage tank in which ice making fluid is stored;
A plate-type ice making heat exchanger in which a brine flow path through which brine flows and a flow path for the ice making fluid through which the ice making fluid flows are formed between a plurality of heat transfer plates disposed opposite to each other;
An ice making fluid circulation circuit for circulating the ice making fluid between the heat storage tank and the ice making heat exchanger;
A brine circulation circuit for guiding the brine cooled by the refrigerator to the ice-making heat exchanger;
Have
A heat storage ice making device that heats the ice making fluid and brine in the ice making heat exchanger to cool the ice making fluid to a supercooled state and return it to the heat storage tank to produce sherbet-like ice. ,
An aqueous solution is used as the ice-making fluid, and when the amount of brine circulating in the brine circulation circuit falls below a predetermined flow rate with a decrease in the temperature of the brine, the flow control means returns to the predetermined flow rate. Ice storage device for heat storage.

  (10) The temperature at which the aqueous solution is made higher than the ice-liquid coexistence temperature is 0.5 ° C. to 1.5 ° C., and the temperature at which the refrigerant is at a temperature lower than the ice-liquid coexistence temperature is 3.5 ° C. to 4 ° C. (5) The ice storage device for heat storage according to (7), which is 5 ° C.

  (11) The ice storage device for heat storage according to (7) to (10), wherein the aqueous solution is an alcohol aqueous solution.

  (12) The heat storage ice making device according to any one of (7) to (10), wherein the aqueous solution is a sodium chloride aqueous solution.

  The present invention uses an aqueous solution as an ice making fluid, controls the temperature of the aqueous solution based on the ice liquid coexisting temperature in the heat storage tank, and makes ice, making it possible to cool at lower temperatures while taking advantage of the supercooling method. You can get a source.

  In the inventions of claims 1 and 7, the temperature of the aqueous solution flowing into the ice-making heat exchanger is controlled based on the ice liquid coexistence temperature, and for the refrigerant, the refrigerator is controlled to control the temperature of the refrigerant. Since the temperature is controlled based on the temperature, the aqueous solution in the ice-making heat exchanger can be stably supercooled with simple control. Can be obtained.

  According to the second and eighth aspects of the present invention, when the flow rate of the aqueous solution guided from the heat storage tank to the ice-making heat exchanger decreases from the predetermined flow rate due to the temperature drop and the increase in viscosity due to concentration, the flow rate of the aqueous solution is determined by adjusting the flow control means. Since the flow rate is restored, the aqueous solution is concentrated as the amount of ice is increased, the freezing point is lowered, and even when the viscosity of the aqueous solution is increased, the flow rate of the aqueous solution is secured and a stable supercooled state can be obtained.

  According to the third and ninth aspects of the present invention, when the flow rate of the brine from the refrigerator to the ice making heat exchanger falls below the predetermined flow rate due to the temperature drop of the brine, the flow rate of the brine is returned to the predetermined flow rate by adjusting the flow rate control means. Even if the viscosity of the brine increases, the flow rate of the brine is secured and a stable supercooled state can be obtained.

  In the inventions of claims 4 and 10, the temperature of the aqueous solution is raised by 0.5 to 1.5 ° C. from the ice liquid coexisting temperature, and the refrigerant temperature is a low temperature state of 3.5 ° C. to 4.5 ° C. from the ice liquid coexisting temperature. By doing so, the aqueous solution can be stably supercooled in the ice making heat exchanger.

  In the fifth, sixth, eleventh and twelfth inventions, since the aqueous solution is an alcohol aqueous solution or a sodium chloride aqueous solution, a low-temperature cold heat source can be obtained easily and inexpensively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an outline of an ice storage device for heat storage according to an embodiment of the present invention, and FIG. 2 is a schematic perspective view showing a plate heat exchanger.

  As shown in FIG. 1, the heat storage ice making device according to the present embodiment includes a heat storage tank 1 in which an aqueous solution W as an ice making fluid is stored, an ice making heat exchanger 10, a heat storage tank 1, and ice making heat exchange. Between the aqueous solution circulation circuit 2 for circulating the aqueous solution W between the cooler 10, the brine tank 4 for storing the brine B cooled by the refrigerant from the refrigerator 3, and between the brine tank 4 and the ice making heat exchanger 10. A brine circulation circuit 5 that circulates the brine B.

  As shown in FIG. 2, the ice making heat exchanger 10 includes an aqueous solution W formed between the brine flow path 12 and the brine flow path 12 between the plurality of heat transfer plates 11 arranged to face each other. Is a plate type heat exchanger having an aqueous solution flow path 13. This plate-type heat exchanger has a large heat transfer area between the brine B and the aqueous solution W, and therefore has excellent heat exchange performance. The capacity can be easily adjusted by increasing or decreasing the number of heat transfer plates 11, and the size of the plate heat exchanger can be reduced. There are many advantages such as saving space and facilitating maintenance and inspection of the heat transfer plate 11. In particular, the plate-type heat exchanger is not suitable for ice making because of its narrow and complicated liquid flow path, but this is possible by controlling the temperature and flow rate as described above.

  The aqueous solution circulation circuit 2 includes an inflow side pipe 2 a that guides the aqueous solution W in the heat storage tank 1 to the ice making heat exchanger 10, and a discharge side pipe 2 b that guides the aqueous solution W discharged from the ice making heat exchanger 10 to the heat storage tank 1. And have.

The inflow side duct 2a includes a temperature sensing member 21 for detecting the temperature of the aqueous solution W in the thermal storage tank 1, a pump P ₁ for aqueous solution for circulating the aqueous solution W, the flow rate control for controlling the amount of the aqueous solution W flowing When the temperature of the aqueous solution W flowing out from the valve 22 and the heat storage tank 1 becomes equal to or lower than the ice liquid coexistence temperature Tk ° C., the preheating means 23 for preheating the aqueous solution W and the temperature T ₁ ° C. of the aqueous solution W flowing into the ice making heat exchanger 10 Measurement data from the inflow temperature detection member 24 for detecting the flow rate, the flowmeter 25 for the aqueous solution for detecting the flow rate of the circulating aqueous solution W, the in-tank temperature detection member 21, the inflow temperature detection member 24, and the flowmeter 25 are input. , an aqueous solution controller Cw for controlling the pump P ₁ and the flow control valve 22 or preheating means 23, is provided by these measurement data.

  Since the discharge side pipe 2b is a pipe that returns the supercooled aqueous solution W in the ice making heat exchanger 10 to the heat storage tank 1, the discharge side pipe 2b itself is a supercooled aqueous solution. It is preferable to use a smooth material and a resin material so that W flows smoothly without blocking, and the curvature radius of the bent portion of the pipe is set to be as large as possible, and the supercooled aqueous solution It is preferable that W flows smoothly without being stimulated. The end 26 on the side of the heat storage tank of the discharge side pipe 2 b is an open end facing the upper part of the heat storage tank 1, and the phase is changed by discharging the supercooled aqueous solution W to the heat storage tank 1. It is like that. When the aqueous solution W brought into the supercooled state returns to the inside of the heat storage tank 1, the supercooling is released by colliding with the liquid surface, and a part of the phase changes to become sherbet-like ice K.

  The brine circulation circuit 5 includes an inflow side conduit 5 a that guides the brine B stored in the brine tank 4 to the ice making heat exchanger 10, and an exhaust side conduit that returns the brine B that has flowed out of the ice making heat exchanger 10 to the brine tank 4. 5b.

The inflow side pipe 5a is provided with a pump P ₂ for brine sending the brine B from the brine tank 4 to the ice heat exchanger 10, a flow control valve 52 to control the amount of brine B flowing, ice heat exchanger 10, an inflow temperature detecting member 54 for detecting the temperature T ₂ ° C. of the brine B flowing in 10, a brine flow meter 55 for detecting the flow rate of the circulating brine B, and a measurement from the inflow temperature detecting member 54 and the flow meter 55. data is input, and brine controller Cb for controlling the pump P ₂ and the valve 52 or the refrigerator 3, is provided by the measurement data.

  Next, the ice storage method for heat storage according to the present embodiment will be described.

When the aqueous solution W as the ice making fluid is in a normal temperature state and the refrigerator 3 and the pumps P ₁ and P ₂ are operated in this state, the brine B cooled by the refrigerator 3 is stored in the brine tank 4, and the brine tank The brine B taken out from the pump 4 by the pump P ₂ and the aqueous solution W in the heat storage tank 1 taken out by the pump P ₁ flow into the ice-making heat exchanger 10, exchange heat with each other, and the aqueous solution W having a low temperature. Is returned to the heat storage tank 1 through the discharge side pipe 2b, and the brine B is also returned to the brine tank 4.

  In the time zone shortly after the start of operation, the water in the aqueous solution W is gradually solidified in the heat storage tank 1 and sherbet-like ice K having a small particle size increases. As the ice K increases, the aqueous solution W As a result, the freezing point temperature Tg ° C. of the aqueous solution W also decreases.

However, in this embodiment, the temperature of the aqueous solution W flowing out from the heat storage tank 1 mixed with ice liquid and the ice liquid coexistence temperature Tk ° C. are the same as the freezing point Tg ° C., and this ice liquid coexistence temperature Tk ° C. (= The temperature T ₁ ° C. of the aqueous solution W flowing into the ice making heat exchanger 10 is controlled on the basis of Tg ° C.), and the aqueous solution W is allowed to flow out of the ice making heat exchanger 10 in a normal supercooled state. Yes.

  In addition, the fluid viscosity of the aqueous solution W increases as the aqueous solution W concentrates and the temperature decreases, but the flow rate of the aqueous solution W flowing into the ice-making heat exchanger 10 seems to be increased due to this increase in viscosity. Unless the reduction in the flow rate is dealt with, the aqueous solution W cannot be allowed to flow in a normal supercooled state, so the flow rate of the aqueous solution W is also controlled.

  The brine B must maintain a predetermined temperature lower than the ice liquid coexistence temperature Tk ° C. (= Tg ° C.), and the viscosity of the brine B increases as the temperature of the brine B decreases, as with the aqueous solution W. Along with this, a decrease in the flow rate of the brine B flowing through the brine circulation circuit 5 occurs.

  Therefore, in the ice storage method for heat storage according to the present embodiment, the temperature control of the aqueous solution W or brine B is performed in order to cause the aqueous solution W to flow out of the ice making heat exchanger 10 in a supercooled state and to smoothly change the phase in the heat storage tank 1. And it prevents the flow rate from decreasing. The temperature control and flow rate control of the aqueous solution and the temperature control and flow rate control of the brine will be described separately.

<Temperature control of aqueous solution>
With continued operation of the refrigerator 3 and the pump P _1, an aqueous solution W in the heat storage tank 1 is gradually cooled, also increases the amount of ice. Along with this, the concentration of the aqueous solution W in the heat storage tank 1 also increases, the freezing point temperature Tg of the aqueous solution W decreases, and the temperature of the aqueous solution W in the heat storage tank 1 also decreases.

  However, the ice liquid coexistence temperature Tk ° C. (= Tg ° C.), which is the temperature of the aqueous solution W flowing out from the heat storage tank 1 in the state where the aqueous solution W and ice K coexist, is the same temperature as the freezing point Tg ° C. In this embodiment, the aqueous solution control unit Cw and the aqueous solution control unit Cw control the temperature of the brine B and the temperature of the aqueous solution W with reference to the ice solution coexistence temperature Tk ° C.

Aqueous controller Cw is the temperature T ₁ of the immediately before flowing into the ice making heat exchanger 10 of the aqueous solution W is detected by inlet temperature sensing member 24, the ice-liquid coexisting temperature Tk ° C. was detected by chamber temperature detection member 21 (= Tg ° C.) as compared to, T ₁ is passed directly if a higher temperature than Tk, if low temperature, heat the aqueous solution W actuates the preheating means 33, the temperature T ₁ of the aqueous solution W to a constant temperature of Tk + alpha enhanced After that, it is made to flow into the ice making heat exchanger 10.

T ₁ = Tk + α (1)
Temperature control is performed in relation to

  Here, it has been proved by experiments that “α” may be in the range of 0.5 ° C. to 1.5 ° C. This value indicates that when the aqueous solution W having the ice liquor coexistence temperature Tk ° C. flows into the ice making heat exchanger 10, the aqueous solution W does not freeze and becomes a normal supercooled state and stably flows out of the ice making heat exchanger 10. The case where it does is calculated | required by experiment.

  Therefore, in this embodiment, the temperature of the aqueous solution W immediately before flowing into the ice making heat exchanger 10 is controlled on the basis of the ice liquid coexistence temperature Tk ° C. (= Tg ° C.). Then, it is cooled by the brine B and easily enters a supercooled state, flows out of the ice making heat exchanger 10 in a liquid state, undergoes a phase change in the heat storage tank 1 and is stored.

<Brine temperature control>
On the other hand, since the temperature of the aqueous solution W also changes depending on the temperature of the brine B, the temperature of the brine B needs to be controlled. The temperature T _{2 of the} brine B needs to be lower than the ice liquid coexistence temperature Tk = Tg ° C. of the aqueous solution W by a predetermined temperature β.

T ₂ = Tk−β (2)
Is necessary.

  Here, it has been proved by experiments that “β” may be in the range of 3.5 ° C. to 4.5 ° C. This value is also obtained when the aqueous solution W having the ice liquor coexistence temperature Tk ° C. flows into the ice making heat exchanger 10 and the aqueous solution W is not frozen and flows out of the ice making heat exchanger 10 in a normal supercooled state. It was obtained by experiment.

Brine controller Cb the temperature T ₂ of the brine B in which the inlet temperature detecting member 54 detects that, so as to satisfy the equation (2), and controls the operation state of the refrigerator 3, flows into the ice making heat exchanger 10 temperature _{T 2} of the brine B which is controlled to be in an ice-liquid coexistent temperature Tk ℃ (= Tg ℃) than 3.5 ° C. ~ 4.5 ° C. lower temperature of the aqueous solution W.

  As a result, the brine B cools the aqueous solution W so that the aqueous solution W does not freeze in the ice making heat exchanger 10 and smoothly flows out while maintaining the supercooled state.

<Flow control of aqueous solution>
As the aqueous solution W concentrates and the freezing point temperature Tg decreases, the fluid viscosity of the aqueous solution W increases, and the flow rate of the aqueous solution W flowing into the ice-making heat exchanger 10 decreases. When the flow rate of the aqueous solution W is decreased and the brine B is flowing normally, the temperature of the aqueous solution W is decreased, and there is a possibility that the aqueous solution W may not flow smoothly while maintaining a supercooled state in the ice making heat exchanger 10.

For this reason, in this embodiment, a normal state flow rate in which the aqueous solution W smoothly flows while maintaining the supercooled state in the ice making heat exchanger 10 is input in advance to the aqueous solution control unit Cw, and the aqueous solution circulation circuit 2, if it is determined that the flow rate of the aqueous solution W has decreased, the opening degree of the flow control valve 22 is increased and the flow rate of the aqueous solution W is increased. Incidentally, increasing the rotational speed of the pump P ₁ by a signal from an aqueous solution controller Cw, it may increase the flow rate of the aqueous solution W.

  As a result, a predetermined flow rate of the aqueous solution W flowing into the ice making heat exchanger 10 is secured, and the aqueous solution W can flow in a normal supercooled state.

<Brine flow rate control>
As for brine B, the viscosity increases due to the temperature drop. In particular, the brine B once stored in the brine tank is easily affected by the outside air temperature, and when the outside air temperature decreases, the viscosity increases accordingly.

  If the viscosity of the brine B increases, the flow rate of the brine B flowing through the brine circulation circuit 5 will decrease, and the cooling capacity of the aqueous solution W may decrease.

For this reason, in the present embodiment, a normal state flow rate in which the aqueous solution W smoothly flows while maintaining the supercooled state in the ice making heat exchanger 10 is input in advance to the aqueous solution control unit Cw, and the brine circulation circuit 5, if it is determined that the flow rate of the brine B has decreased, the opening degree of the flow control valve 52 is increased, and the flow rate of the brine B is increased. Incidentally, increasing the rotational speed of the pump P ₂ by a signal from the brine control unit Cb, it may increase the flow rate of the brine B.

  As a result, the brine B flowing into the ice-making heat exchanger 10 can have a predetermined flow rate at which normal heat exchange is performed even if the viscosity of the brine B increases, and can be made into a normal supercooled aqueous solution W. .

<Experimental example 1>
FIG. 3 is a measurement data table showing the experimental results of 0.80 vol% alcohol aqueous solution, and FIG. 4 is a graph created based on the measurement data table.

As aqueous solution W, 0.80% by volume of alcohol was used, and as brine B, an ethylene glycol solution was used. The circulation flow rate of the aqueous solution W was kept constant at 1.00 m ³ / h, and the circulation flow rate of the brine B was kept constant at 1.40 m ³ / h. The temperature Tk ° C. (= Tg ° C.) of the aqueous solution W flowing out from the heat storage tank 1 and the temperature T ₁ ° C. of the solution flowing into the ice making heat exchanger 10 are measured, and the temperature of the aqueous solution W flowing into the ice making heat exchanger 10 is Control was performed so that T ₁ = Tk + α ° C. α was set to 1.5 ° C.

On the other hand, the temperature T ₂ flowing into the ice making heat exchanger 10 of the brine B was measured, and the temperature flowing into the ice making heat exchanger 10 of the brine B was controlled to be T ₂ = Tk−β ° C. β was set to 4.5 ° C.

  As a result, as shown in FIG. 3, the temperature of the aqueous solution W at the outlet of the ice making heat exchanger 10 is approximately −1.34 ° C. to −1.49 ° C., and the stable supercooled aqueous solution W flows. This was sent into the heat storage tank 1 to change the phase and became sherbet-like ice. The temperature in the heat storage tank 1 also became a stable temperature state of approximately −0.22 ° C. to −0.27 ° C.

<Experimental example 2>
FIG. 5 is a measurement data table showing experimental results of 1.20 vol% alcohol aqueous solution, and FIG. 6 is a graph created based on the measurement data table.

As the aqueous solution W, 1.20 vol% alcohol was used, and as the brine B, the same ethylene glycol solution as described above was used. The circulation flow rate of the aqueous solution W was 1.00 m ³ / h, and the circulation flow rate of the brine B was also 1.40 m ³ / h. The temperature Tk ° C. (= Tg ° C.) of the aqueous solution W flowing out of the heat storage tank 1 and the temperature T ₁ of the aqueous solution W flowing into the ice making heat exchanger 10 are measured, and the temperature of the aqueous solution W flowing into the ice making heat exchanger 10 is Control was performed so that T ₁ − = Tg + α. α was set to 1.5 ° C.

On the other hand, the temperature T ₂ flowing into the ice making heat exchanger 10 of the brine B was measured, and the temperature flowing into the ice making heat exchanger 10 of the brine B was controlled to be T ₂ = Tk−β. β was set to 4.5 ° C.

  As a result, as shown in FIG. 5, the outlet temperature of the ice making heat exchanger 10 is approximately −1.36 ° C. to −1.59 ° C., and a stable supercooled aqueous solution W flows, which is the heat storage tank 1. It was sent inside and changed in phase to become sorbet-like ice. The temperature in the heat storage tank 1 also became a stable temperature state of approximately −0.32 ° C. to −0.44 ° C.

<Experimental example 3>
FIG. 7 is a measurement data table showing experimental results of a 3.38 wt% sodium chloride aqueous solution, and FIG. 8 is a graph created based on the measurement data table.

A 3.38 wt% sodium chloride solution was used as aqueous solution W, and a sodium chloride solution was used as brine B. The circulation flow rate of the aqueous solution W was kept constant at 1.00 m ³ / h, and the circulation flow rate of the brine B was kept constant at 1.10 m ³ / h. The temperature at which the aqueous solution W flows out from the heat storage tank 1 is Tk ° C. (= Tg ° C.) and the temperature T ₁ at which the aqueous solution W flows into the ice making heat exchanger 10 is measured, and the temperature at which the aqueous solution W flows into the ice making heat exchanger 10 Was controlled to be T ₁ = Tk + α. α was set to 1.5 ° C.

On the other hand, the temperature T ₂ flowing into the ice making heat exchanger 10 of the brine B was measured, and the temperature flowing into the ice making heat exchanger 10 of the brine B was controlled to be T ₂ = Tk−β. β was set to 4.5 ° C.

  As a result, as shown in FIG. 7, the outlet temperature of the ice making heat exchanger 10 is approximately −1.36 ° C. to −1.59 ° C., and a stable supercooled aqueous solution W flows, which is the heat storage tank 1. It was sent inside and changed in phase to become sorbet-like ice. The temperature in the heat storage tank 1 also became a stable temperature state of approximately −2.06 ° C. to −2.52 ° C.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, in the embodiment, the temperature control and flow rate control of the aqueous solution and the temperature control and flow rate control of the brine are all performed, but not all the control is performed, the temperature control of the aqueous solution W and the brine B, the aqueous solution W Or the brine B flow control may be performed individually. If only the temperature control of the aqueous solution W and the brine B is performed, the aqueous solution W can be allowed to flow in a normal supercooled state even if the freezing point temperature Tg ° C. of the aqueous solution W decreases. Moreover, if only the flow rate control of the aqueous solution W or the flow rate control of the brine B is performed, it is possible to cope with an increase in viscosity accompanying a decrease in the freezing point temperature Tg ° C. of the aqueous solution W or the brine B. Effective when making ice using the aqueous solution W It demonstrates the nature.

  In this embodiment, for example, an ethylene glycol solution is used as the brine B. However, not only this but also various solutions such as potassium chloride, ammonia, magnesium chloride, potassium carbonate, calcium chloride are used. Needless to say, you can.

  The ice storage method and apparatus for heat storage according to the present invention are suitable for obtaining a low-temperature cold heat source in the field of food and beverages.

It is the schematic of the ice-making apparatus for thermal storage which concerns on embodiment of this invention. It is a schematic perspective view which shows a plate type heat exchanger. It is a graph which shows the experimental result of 0.80 volume% alcohol aqueous solution. It is a measurement data table | surface which shows the experimental result of the same alcohol aqueous solution. It is a graph which shows the experimental result of 1.20 volume% alcohol aqueous solution. It is a measurement data table | surface which shows the experimental result of the same alcohol aqueous solution. It is a graph which shows the experimental result of 3.38 weight% sodium chloride aqueous solution. It is a measurement data table | surface which shows the experimental result of the sodium chloride aqueous solution.

Explanation of symbols

1 ... thermal storage tank,
2 ... Fluid circulation circuit for ice making,
3 ... Refrigerator,
5 ... refrigerant circulation circuit,
10. Plate type ice making heat exchanger (ice making heat exchanger),
11 ... Heat transfer plate,
12 ... Flow path for refrigerant,
13 ... Flow path for ice making fluid,
22 ... Flow control valve (flow control means),
23. Preheating means,
52 ... Flow control valve (flow control means),
B ... Brine (refrigerant),
Cb: refrigerant temperature control unit,
Cw: aqueous solution control unit,
K ... ice,
T ₁ ... temperature of the aqueous solution,
T ₂ ... temperature of brine (refrigerant),
Tg: freezing point temperature of aqueous solution,
Tk ... Ice liquid coexistence temperature,
W: Aqueous solution.

Claims (12)

The ice making fluid from the inside of the heat storage tank and the brine cooled by the refrigerator are each led to an ice making heat exchanger to exchange heat, and the ice making fluid is cooled to a supercooled state to enter the heat storage tank. An ice-making method for storing heat that returns and produces sherbet-shaped ice,
An aqueous solution is used as the ice-making fluid, and the temperature of the aqueous solution introduced into the ice-making heat exchanger is higher by a predetermined temperature than the ice liquid coexisting temperature of the aqueous solution in the heat storage tank. An ice making method for heat storage, wherein the temperature is controlled so that the temperature of the brine guided to the vessel is lower than the ice liquid coexistence temperature by a predetermined temperature, and the brine is introduced into the ice making heat exchanger. The ice making fluid from the inside of the heat storage tank and the brine cooled by the refrigerator are each led to an ice making heat exchanger to exchange heat, and the ice making fluid is cooled to a supercooled state to enter the heat storage tank. An ice-making method for storing heat that returns and produces sherbet-shaped ice,
When an aqueous solution is used as the ice-making fluid, and the flow rate of the aqueous solution guided from the heat storage tank to the ice-making heat exchanger becomes equal to or less than a predetermined flow rate due to a temperature drop and concentration increase due to the concentration of the aqueous solution, An ice making method for heat storage, characterized by returning to a predetermined flow rate. The ice making fluid from the inside of the heat storage tank and the brine cooled by the refrigerator are each led to an ice making heat exchanger to exchange heat, and the ice making fluid is cooled to a supercooled state to enter the heat storage tank. An ice-making method for storing heat that returns and produces sherbet-shaped ice,
An aqueous solution is used as the ice making fluid, and when the flow rate of the brine introduced from the refrigerator to the ice making heat exchanger becomes a predetermined flow rate or less with a temperature drop, the flow rate control means returns the flow rate to the predetermined flow rate. Ice making method for heat storage.   The temperature at which the aqueous solution is made higher than the ice liquor coexistence temperature is 0.5 ° C to 1.5 ° C, and the temperature at which the refrigerant is at a temperature lower than the ice liquor coexistence temperature is 3.5 ° C to 4.5 ° C. The ice making method for heat storage according to claim 1.   The said aqueous solution is alcohol aqueous solution, The ice-making method for thermal storage in any one of Claims 1-4.   The said aqueous solution is sodium chloride aqueous solution, The ice-making method for thermal storage in any one of Claims 1-4. A heat storage tank in which ice-making fluid is stored;
A plate-type ice-making heat exchanger in which a flow path for refrigerant in which brine flows and a flow path for the ice-making fluid in which the ice-making fluid flows are formed between a plurality of opposed heat transfer plates;
An ice making fluid circulation circuit for circulating the ice making fluid between the heat storage tank and the ice making heat exchanger;
A refrigerant circulation circuit for guiding brine cooled by a refrigerator to the ice making heat exchanger;
Have
A heat storage ice making device for producing a sherbet-like ice by cooling the ice making fluid to a supercooled state by exchanging heat between the ice making fluid and the refrigerant in the ice making heat exchanger. ,
An aqueous solution is used as the ice making fluid, and an aqueous solution control unit that controls the temperature of the aqueous solution flowing into the ice making heat exchanger to be higher than the ice solution coexistence temperature by a predetermined temperature; and the temperature of the brine is the ice solution An ice making device for heat storage, comprising: a refrigerant temperature control unit that controls a temperature lower than the coexistence temperature by a predetermined temperature. A heat storage tank in which ice-making fluid is stored;
A plate-type ice making heat exchanger in which a refrigerant flow path through which brine flows and a flow path for ice making fluid through which the ice making fluid flows are alternately formed between a plurality of opposed heat transfer plates;
An ice making fluid circulation circuit in which the ice making fluid is circulated between the heat storage tank and the ice making heat exchanger;
A brine circulation circuit in which brine is circulated between a refrigerator and the ice making heat exchanger;
Have
A heat storage ice making device for producing a sherbet-like ice by cooling the ice making fluid to a supercooled state by exchanging heat between the ice making fluid and brine in the ice making heat exchanger,
Flow control using an aqueous solution as the ice-making fluid, and returning the flow rate of the aqueous solution circulating through the ice-making fluid circulation circuit to the predetermined flow rate when the flow rate of the aqueous solution decreases below a predetermined flow rate due to a temperature drop and concentration increase due to concentration. An ice making apparatus for heat storage, characterized by comprising means. A heat storage tank in which ice-making fluid is stored;
A plate-type ice making heat exchanger in which a brine flow path through which brine flows and a flow path for the ice making fluid through which the ice making fluid flows are formed between a plurality of heat transfer plates disposed opposite to each other;
An ice making fluid circulation circuit for circulating the ice making fluid between the heat storage tank and the ice making heat exchanger;
A brine circulation circuit for guiding the brine cooled by the refrigerator to the ice-making heat exchanger;
Have
A heat storage ice making device for producing a sherbet-like ice by cooling the ice making fluid to a supercooled state by exchanging heat between the ice making fluid and brine in the ice making heat exchanger. ,
An aqueous solution is used as the ice-making fluid, and when the amount of brine circulating in the brine circulation circuit falls below a predetermined flow rate with a decrease in the temperature of the brine, the flow control means returns to the predetermined flow rate. Ice storage device for heat storage.   The temperature at which the aqueous solution is made higher than the ice liquor coexistence temperature is 0.5 ° C to 1.5 ° C, and the temperature at which the refrigerant is at a temperature lower than the ice liquor coexistence temperature is 3.5 ° C to 4.5 ° C. The ice storage device for heat storage according to claim 7.   The ice storage device for heat storage according to any one of claims 7 to 10, wherein the aqueous solution is an aqueous alcohol solution.   The said aqueous solution is sodium chloride aqueous solution, The ice making apparatus for thermal storage in any one of Claims 7-10.

Images