JP2004271090A - Method of operating heat storage tank for cold transporting medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of operating a heat storage tank for a cold transporting medium for efficiently extracting hydrate slurry while suppressing the formation of a liquid path in a layer of the hydrate slurry. <P>SOLUTION: The method of operating the heat storage tank for the cold transporting medium is provided for storing water solution of a guest compound for producing hydrate at a temperature higher than 0°C and the hydrate slurry to be produced by cooling the solution. The heat storage tank has a plurality of sections for sectioning the heat storage tank, water solution pipes connected to the sections, water solution pipe on-off valves provided in the water solution pipes in the sections, slurry pipes connected to the sections, and slurry pipe on-off valves provided in the slurry pipes in the sections. The water solution pipe on-off valves and the slurry pipe on-off valves are operated so that the hydrate slurry is extracted from one section during cold utilizing operation and the water solution is stored in the other sections. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for operating a heat storage tank for a cold transport medium.
[0002]
[Prior art]
Attention has been paid to using a hydrate slurry instead of cold water or ice slurry as a cooling / transporting medium in building air conditioning or district heating / cooling. That is, when an aqueous solution containing a guest compound (for example, various salts such as tetra-n-butylammonium salt, tetra-iso-amyl ammonium salt, tetra-iso-butylphosphonium salt, and tri-iso-amyl sulfonium salt) is cooled, water as a host molecule is cooled. The guest compound is wrapped and crystallized in a cage-shaped clathrate lattice composed of molecules, and a hydrate (liquid clathrate hydrate) is generated. This hydrate can be formed at a temperature of 0 ° C. or higher under atmospheric pressure, and has a large latent heat and can store cold heat several times as much as cold water. A hydrate slurry in which a hydrate, which is fine crystal particles, is suspended in an aqueous solution is superior to an ice slurry in that it has relatively high fluidity. For this reason, such a hydrate slurry has favorable characteristics as a cold transport medium.
[0003]
In a system that uses hydrate slurry as a cold and heat transport medium, hydrate slurry is manufactured and stored in a thermal storage tank at night, and hydrated during the day, in order to make effective use of power at night and level the power load. A method is generally used in which material slurry is extracted from a heat storage tank and used as a cold heat source.
[0004]
FIG. 6 shows a cold heat utilization system using a hydrate slurry as a cold heat transport medium.
A typical operation method of such a cold heat utilization system is as follows. At night (during heat storage operation), the aqueous solution in the heat storage tank 101 is sent to the slurry manufacturing apparatus 103 by the primary pump 102 and cooled to produce hydrate slurry, and the produced hydrate slurry is stored in the heat storage tank. Return to 101 and store. In the daytime (at the time of the operation using cold heat), the hydrate slurry stored in the heat storage tank 101 is sent to the load side air conditioner 105 by the secondary pump 104 to use the cold heat. Since the hydrate slurry becomes an aqueous solution by heat exchange with indoor air, this aqueous solution is returned to the heat storage tank 101.
[0005]
However, in the heat storage tank as shown in FIG. 6, when attempting to extract the hydrate slurry, only the aqueous solution is extracted, and there is a problem that the hydrate slurry cannot be efficiently extracted. Was. This is a phenomenon that occurs because the viscosity of the hydrate slurry and the viscosity of the aqueous solution are greatly different, and a so-called liquid path (aqueous solution passage) is formed in the layer of the hydrate slurry.
[0006]
Conventionally, it has been proposed to solve this problem by devising a method of extracting a hydrate slurry from a heat storage tank in which an aqueous solution and a hydrate slurry are stored (for example, see Patent Document 1). Specifically, (1) pulsating the flow rate of the hydrate slurry taken out, (2) rotating a stirring blade provided in the vicinity of a pipe for extracting the hydrate slurry, (3) stirring installed in the heat storage tank Methods of rotating the blades, (4) ejecting the hydrate slurry from a nozzle disposed near a pipe for extracting the hydrate slurry, and the like are disclosed. However, these methods mainly take countermeasures after detecting the formation of liquid channels, and the efficiency of extracting hydrate slurry is insufficient because the effect of suppressing the formation of liquid channels is insufficient. Has room for improvement. Also disclosed is a method of suppressing the formation of a liquid passage or extinguishing the formed liquid passage by using a plurality of resistors suspended from a movable floating body on the liquid surface in the heat storage tank. The effect of suppressing the formation of the hydrate slurry is insufficient, and the resistor may block the inlet of the hydrate slurry pipe. In particular, in these methods, when a large-capacity heat storage tank is required, it has been difficult to suppress the formation of liquid channels.
[0007]
[Patent Document 1]
JP-A-2002-333166
[Problems to be solved by the invention]
An object of the present invention is to control the formation of a liquid path of an aqueous solution in a layer of a hydrate slurry, and to efficiently extract a hydrate slurry even when a large amount of heat storage is required. An object of the present invention is to provide a method of operating a heat storage tank for a transport medium.
[0009]
[Means for Solving the Problems]
The operation method of the heat storage tank for a cold transport medium according to the present invention stores an aqueous solution of a guest compound that generates hydrate at a temperature higher than 0 ° C., and a hydrate slurry produced by cooling the aqueous solution. A method of operating a heat storage tank for a cold heat transport medium, wherein the heat storage tank includes a plurality of sections that divide the heat storage tank, an aqueous solution pipe connected to each section, and an aqueous solution pipe provided in the aqueous solution pipe of each section. A valve, a slurry pipe connected to each section, and a slurry pipe opening / closing valve provided in the slurry pipe of each section, and withdraws hydrate slurry from one section during cold utilization operation to another section. The aqueous solution piping on-off valve and the slurry piping on-off valve are operated so as to store the aqueous solution.
[0010]
In the operation method of the heat storage tank for a cold transport medium according to the present invention, the heat storage tank has three or more sections, and starts the cold heat utilization operation from a state in which the hydrate slurry is stored in the two or more sections. The operation of extracting the hydrate slurry from one compartment and storing the aqueous solution in an adjacent compartment is preferably performed while sequentially moving the compartments to be operated.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
In the heat storage tank for a cold heat transport medium of the present invention, the heat storage tank is divided into a plurality of sections, and an aqueous solution pipe opening / closing valve is provided so that a hydrate slurry is extracted from one section and stored in another section during cold utilization operation. And operate the slurry piping on-off valve.
[0012]
As described above, the section from which the hydrate slurry is extracted is different from the section from which the aqueous solution is returned after using the cold energy, and the aqueous solution is not mixed into the section from which the hydrate slurry is extracted. Hydrate slurry can be efficiently extracted by suppressing the formation of liquid channels.
[0013]
In particular, the heat storage tank is divided into many sections of three or more, and the hydrate slurry is stored in the two or more sections, and the operation using the cold heat is started to extract the hydrate slurry from one section. If the operation of storing the aqueous solution in the adjacent compartments is performed while sequentially moving the compartments to be operated, efficient extraction of the hydrate slurry can be realized over many compartments, so that the capacity of the heat storage tank is reduced. It is effective when increasing.
[0014]
Note that the purpose of the present invention is to suppress the formation of a liquid path in the layer of the hydrate slurry when extracting the hydrate slurry during the cold heat operation, and the above is described only during the cold heat operation. The operation of the aqueous solution piping on-off valve and the slurry piping on-off valve may be performed. However, even during the heat storage operation, the aqueous solution pipe opening / closing valve and the slurry pipe opening / closing valve may be operated so as to extract the aqueous solution from one section and store the hydrate slurry in another section. In addition, the heat storage tank is divided into three or more compartments, the heat storage operation is started from a state in which the aqueous solution is stored in two or more compartments, the aqueous solution is extracted from one compartment, and hydrated in the adjacent compartment. The operation of storing the object slurry may be performed while sequentially moving the section to be operated.
[0015]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system diagram showing a cold heat utilization system including a heat storage tank for a cold heat transport medium according to the present invention. FIG. 2 is a plan view of the heat storage tank of FIG. 1 and 2, the heat storage tank 1 is divided into, for example, four sections 1a, 1b, 1c, and 1d.
An aqueous solution pipe 2 is connected to the four sections 1a, 1b, 1c, and 1d, and aqueous solution pipe opening / closing valves 3a, 3b, 3c, and 3d for opening and closing the aqueous solution pipe 2 are provided for the respective sections. Similarly, a slurry pipe 4 is connected to the four sections 1a, 1b, 1c, and 1d, and slurry pipe opening / closing valves 5a, 5b, 5c, and 5d for opening and closing the slurry pipe 4 are provided corresponding to the respective sections. I have. The controller 6 controls opening and closing of the aqueous solution pipe opening and closing valve and the slurry pipe opening and closing valve.
[0016]
FIG. 3 shows an example of a sectional view of the section 1b (heat storage tank 1). In FIG. 3, an aqueous solution pipe 2 and a slurry pipe 4 are provided at both ends of the bottom of the section 1b (heat storage tank 1). A nozzle is provided from the aqueous solution pipe 2 toward the inside, and the aqueous solution pipe opening / closing valve 3b is attached to this nozzle. Similarly, a nozzle is provided inward from the slurry pipe 4, and a slurry pipe open / close valve 5b is attached to the nozzle.
[0017]
FIG. 4 shows another example of a sectional view of the section 1b (heat storage tank 1). In FIG. 4, an aqueous solution pipe 2 and a slurry pipe 4 are provided at both ends of an upper portion of the section 1b (heat storage tank 1). A nozzle is provided from the aqueous solution pipe 2 to the lower side near the bottom of the section 1b, and an aqueous solution pipe opening / closing valve 3b is attached to this nozzle. Similarly, a nozzle is provided from the slurry pipe 4 to the lower side near the bottom of the section 1b, and a slurry pipe opening / closing valve 5b is attached to this nozzle.
[0018]
As shown in FIGS. 3 and 4, the directions of the nozzles provided in the aqueous solution pipe 2 and the slurry pipe 4 are not limited, but the nozzles are preferably arranged near the bottom of each section.
[0019]
The general operation of the cold heat utilization system shown in FIG. 1 is as follows. During the heat storage operation, the aqueous solution in the heat storage tank 1 is sent to the slurry manufacturing device 8 by the primary pump 7 and cooled to produce a hydrate slurry, and the manufactured hydrate slurry is returned to the heat storage tank 1 for storage. I do. The slurry manufacturing device 8 is composed of, for example, a heat exchanger connected to a refrigerator. During the operation using cold heat, the hydrate slurry stored in the heat storage tank 1 is sent to the load-side air conditioner 10 by the secondary pump 9 to use the cold heat. Since the hydrate slurry becomes an aqueous solution by heat exchange with indoor air, this aqueous solution is returned to the heat storage tank 1.
[0020]
In the heat storage tank for the cold transport medium according to the present invention, the hydrate slurry is extracted from one of the plurality of sections 1a to 1d constituting the heat storage tank 1 at the time of the cold energy utilization operation, and the aqueous solution is stored in the other section. The on-off valve for the aqueous solution pipe and the on-off valve for the slurry pipe are operated.
[0021]
With reference to FIGS. 5 (a) to 5 (d) and FIG. 1, the operation of the cold storage medium for heat storage according to the present invention will be described in more detail. In the present invention, it is sufficient to perform the above-described operation only during the cold-heat operation. However, FIGS. 5A to 5D illustrate a case in which the heat storage operation is performed in a substantially reverse operation to the cold-heat operation. .
[0022]
FIGS. 5A to 5D show changes of the aqueous solution 11 or the hydrate slurry 12 stored in each of the sections 1a to 1d of the heat storage tank 1 over time. In FIG. 5, the order changes from (1) to (8) by the operation of the aqueous solution piping on-off valves 3a to 3d and the slurry piping on-off valves 5a to 5d.
[0023]
(1) Before starting the heat storage operation, of the four sections 1a to 1d, the aqueous solution 11 is almost fully stored in the one section 1a to the three sections 1a to 1c, and a slight amount is stored in the other section 1d. It is assumed that the hydrate slurry 12 is stored (FIG. 5a).
[0024]
(2) The heat storage operation is started by opening the aqueous solution pipe opening / closing valve 3c in the section 1c and the slurry pipe opening / closing valve 5d in the section 1d, and the aqueous solution in the section 1c is extracted and produced by cooling in the hydrate slurry manufacturing apparatus 8. The hydrated slurry is stored in section 1d. As a result, the aqueous solution in section 1c decreases and the hydrate slurry in section 1d increases (FIG. 5b).
[0025]
(3) When the aqueous solution in the section 1c is close to empty and the hydrate slurry in the section 1d is full, the on-off valve is switched, and the aqueous solution pipe on-off valve 3b in the section 1b and the slurry pipe on-off valve 5c in the section 1c are opened. Then, the heat storage operation is continued, the aqueous solution in the section 1b is extracted, and the hydrate slurry is stored in the section 1c. As a result, the aqueous solution in section 1b decreases and the hydrate slurry in section 1c increases (FIG. 5c).
[0026]
(4) When the aqueous solution in the section 1b is close to empty and the hydrate slurry in the section 1c is full, the on-off valve is switched, and the aqueous solution pipe on-off valve 3a in the section 1a and the slurry pipe on-off valve 5b in the section 1b are opened. Then, the heat storage operation is continued, the aqueous solution in the section 1a is extracted, and the hydrate slurry is stored in the section 1b. As a result, the aqueous solution in section 1a decreases and the hydrate slurry in section 1b increases (FIG. 5d). At this point, the heat storage operation ends.
[0027]
(5) The state at the end of the heat storage operation in FIG. 5D is also the state before the start of the cold heat utilization operation. Before the operation using the cold heat, a small amount of the aqueous solution 11 is stored in one of the four compartments 1a to 1d, and the hydrate slurry 12 is stored almost completely in the remaining three compartments 1b to 1d. (FIG. 5d). Opening the slurry pipe opening / closing valve 5b in the section 1b and the aqueous solution pipe opening / closing valve 3a in the section 1a to start the cold utilization operation, extracting the hydrate slurry in the section 1b, and using the cold heat in the load side air conditioner 10 The aqueous solution is stored in the compartment 1a. As a result, the hydrate slurry in the section 1b decreases, and the aqueous solution in the section 1a increases.
[0028]
(6) When the hydrate slurry in the section 1b is close to empty and the aqueous solution in the section 1a is full, the on / off valve is switched, and the slurry pipe on / off valve 5c in the section 1c and the aqueous solution on / off valve 3b in the section 1b are connected. Open and continue the cold-heat utilization operation, extract the hydrate slurry in section 1c, and store the aqueous solution in section 1b. As a result, the hydrate slurry in section 1c decreases and the aqueous solution in section 1b increases (FIG. 5c).
[0029]
(7) When the hydrate slurry in section 1c is close to empty and the aqueous solution in section 1b is full, the on / off valve is switched, and the slurry pipe on / off valve 5d in section 1d and the aqueous solution on / off valve 3c in section 1c are connected. Open to continue the cold-heat utilization operation, extract the hydrate slurry in section 1d, and store the aqueous solution in section 1c. As a result, the hydrate slurry in section 1d decreases and the aqueous solution in section 1c increases (FIG. 5b).
[0030]
(8) Further, when the operation using the cold heat is continued, the aqueous solution 11 is stored almost completely in the sections 1a to 1c, and a small amount of the hydrate slurry 12 is stored in the section 1d at the other end (FIG. 5a).
[0031]
As described in the above operations (5) to (8), of the sections 1a to 1d of the heat storage tank 1, the section from which the hydrate slurry is extracted and the section from which the aqueous solution after using the cold heat returns. The difference is that the aqueous solution is not mixed into the section from which the hydrate slurry is extracted, so that the formation of liquid channels can be suppressed and the hydrate slurry can be efficiently extracted. Therefore, it is advantageous when a large-capacity heat storage tank is required.
[0032]
In the present invention, the heat storage tank may be divided into at least two sections. However, the heat storage tank is divided into three or more sections (for example, four as in the above embodiment) and divided into two or more sections. The operation of using the cold heat from the state where the hydrate slurry is stored is started, and the operation of extracting the hydrate slurry from one section and storing the aqueous solution in the adjacent section is performed while sequentially moving the section to be operated. It is more efficient to do so.
[0033]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to suppress the formation of a liquid path of an aqueous solution in a layer of a hydrate slurry, and to efficiently extract a hydrate slurry. A tank can be provided.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a cold heat utilization system including a heat storage tank for a cold heat transport medium (hydrate slurry) according to the present invention.
FIG. 2 is a plan view of the heat storage tank for a cold transport medium according to the present invention.
FIG. 3 is a cross-sectional view showing an example of a heat storage tank for a cold heat transport medium according to the present invention.
FIG. 4 is a cross-sectional view showing another example of the heat storage tank for a cold transport medium according to the present invention.
FIG. 5 is a view for explaining the operation of the heat storage tank for a cold heat transport medium according to the present invention.
FIG. 6 is a system diagram showing a conventional cold heat utilization system using a hydrate slurry.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Thermal storage tank, 1a, 1b, 1c, 1d ... Section: 2 ... Aqueous solution piping, 3a, 3b, 3c, 3d ... Aqueous solution piping opening / closing valve, 4 ... Slurry piping, 5a, 5b, 5c, 5d ... Slurry piping opening / closing valve , 6 ... Controller, 7 ... Primary pump, 8 ... Slurry manufacturing device, 9 ... Secondary pump, 10 ... Load side air conditioner.

Claims (2)

A method of operating a heat storage tank for a cold transport medium storing an aqueous solution of a guest compound that produces hydrate at a temperature higher than 0 ° C. and a hydrate slurry produced by cooling the aqueous solution, The tank includes a plurality of sections for dividing the heat storage tank, an aqueous solution pipe connected to each section, an aqueous solution opening / closing valve provided for the aqueous solution pipe of each section, a slurry pipe connected to each section, and each section. A slurry pipe opening / closing valve provided in the slurry pipe of the first embodiment, wherein the aqueous solution pipe opening / closing valve and the slurry pipe opening / closing so as to extract a hydrate slurry from one section and store an aqueous solution in another section at the time of operation using cold heat. A method for operating a heat storage tank for a cold transport medium, wherein a valve is operated. The heat storage tank has three or more sections, starts a cold-heat utilization operation from a state in which the hydrate slurry is stored in two or more sections, extracts the hydrate slurry from one section, and adjoins the hydrate slurry. The method according to claim 1, wherein the operation of storing the aqueous solution in the compartment is performed while sequentially moving the compartment to be operated.

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