JP2000111283A - Manufacture of inclusion hydrate slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration and to increase a chill transportation density by storing a solution for generating an inclusion hydrate for cooling in a heat storage tank, installing an evaporator for composing a freezing device in the heat storage tank, and evaporating the refrigerant in the evaporator and cooling the solution, and allowing the inclusion hydrate slurry to adhere to the evaporator. SOLUTION: When a solution W is stored in a heat storage tank 1 and a freezing device 4 is operated, a high-temperature high-pressure refrigerant being compressed by a compressor 6 is condensed by a condenser 7 and becomes a liquefied refrigerant. Also, the liquefied refrigerant is guided to an inflation valve 9 through a liquid receiver 8 while pressure is reduced and is guided to an evaporator 5. Further, since the refrigerant absorbs heat around a copper pipe 5a and evaporates, the solution W in the heat storage tank 1 is cooled, an inclusion hydrate is generated and adheres to the surface of the copper pipe 5a, and a solid where it is peeled off is dispersed into the solution and becomes an inclusion hydrate slurry W1 in sherbet shape. In this manner, by a heat storage medium for easily generating the inclusion hydrate even under an atmospheric pressure, earth environmental problems such as ozone destruction can be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a clathrate hydrate slurry used for a heat storage device such as an air conditioner.

[0002]

2. Description of the Related Art Conventionally, various types of heat storage devices used for air conditioning equipment have been developed. By using such a heat storage device, heat is stored using energy that is discontinuously supplied, for example, late-night power, and waste heat of a factory, and the stored cold heat is used for air conditioning equipment, thereby achieving energy saving. Can be used more effectively.

As an example of such a heat storage device, there is a heat storage device using ice. In some of them, ice is produced at night by electric power at midnight, and the cold stored in the ice is used for air conditioning equipment in the daytime. This one is
Compared to the case of using the sensible heat of water, a large amount of cold heat can be stored by the latent heat of ice, but on the other hand, solid ice is formed, making it difficult to handle and exchange heat, making the device complicated and complicated. There is a problem that it becomes larger.

[0004] Another example of a heat storage device uses a hydrate. It is known that water molecules constitute a cage-like structure, and another molecule, ie, a guest molecule, enters the cage-like structure, ie, the host structure, to form an inclusion hydrate. This clathrate hydrate has an appearance and physical properties similar to ice, and the temperature at which this hydrate is formed varies depending on the type and concentration of guest molecules and other conditions. Some hydrates are formed at temperatures above the solidification temperature of

Therefore, by selecting the type of the guest molecule and other conditions, a hydrate can be formed at a temperature higher than the solidification temperature of water, and a slurry in which hydrate particles are mixed in water can be formed. Can be formed. This hydrate slurry has a large heat storage capacity due to the latent heat of the hydrate, and since it is a slurry, it can be transferred via a pipe by a pump or the like, and is easy to handle, and heat exchange is easy. is there. Further, such a hydrate slurry can be used as it is in an existing air conditioner using cold water, or after being subjected to minor renovation.

However, in practice, such hydrate slurry causes hydrate particles to adhere and deposit on, for example, the surface of a cooling pipe, the inside of a pipe, or the wall surface or bottom surface of a heat storage tank for storing the slurry. And solidify in a solid state. Therefore, in order to put a heat storage device using this hydrate slurry into practical use, it is necessary to establish a technique for reliably preventing solidification of particles of the hydrate and producing and maintaining a slurry having high fluidity. It is.

Conventionally, as a regenerative heat storage system, a gas hydrate, which is a kind of clathrate hydrate, is known as a heat storage medium instead of water and ice, as shown in, for example, JP-A-2-203138. This is to store water as a host agent and a chlorofluorocarbon-based refrigerant R11 (trichlorofluoromethane) as a guest agent in a heat storage tank, circulate the guest agent in the heat storage tank through a cool storage cycle system, and evaporate the guest agent. Thus, the evaporated guest agent and the host agent react with each other to generate a gas clathrate.

[0008]

However, the technique described in the above-mentioned Japanese Patent Application Laid-Open No. 2-203138 is
In order to generate a gaseous hydrate, a CFC-based refrigerant R11 is used. Since the CFC-based refrigerant R11 is a substance having a large ozone destruction coefficient and is a gas at atmospheric pressure, it is necessary to use a closed container, and there is a problem that the heat storage device becomes expensive.

The present invention has been made in view of the above circumstances, and an object thereof is to use a heat storage medium which easily generates clathrate hydrate even under atmospheric pressure.
While simplifying the configuration of the heat storage device,
An object of the present invention is to provide a method for producing a clathrate hydrate slurry capable of increasing the cold transport density.

[0010]

According to the present invention, in order to achieve the above object, a first aspect of the present invention is to store an aqueous solution which forms a clathrate hydrate upon cooling in a heat storage tank, and to store the aqueous solution in the heat storage tank. Clathrate hydrate, comprising installing an evaporator constituting a refrigeration apparatus, cooling the aqueous solution by evaporating a refrigerant with the evaporator, and causing a clathrate hydrate slurry to adhere to the evaporator. The method for producing a slurry.

According to a second aspect, the aqueous solution according to the first aspect is any one of a tetra-n-butylammonium salt, a tetra-iso-aluminum ammonium salt, a tetra-n-butylphosphonium salt, and a tri-isoaluminosulfonium salt. There is a feature.

A third aspect of the present invention relates to the aqueous solution of the first aspect,
A substance having a lower freezing point than water is added. A fourth aspect of the present invention is characterized in that the evaporator of the first aspect is a meandering copper tube disposed inside a heat storage tank.

When the aqueous solution is cooled by evaporating the refrigerant by the evaporator in the heat storage tank, clathrate hydrate is generated and adheres to the surface of the evaporator, and hydrated into the liquid by an appropriate adhering portion removing means. Are mixed to produce a sherbet-like clathrate hydrate slurry. This clathrate hydrate slurry has a high fluidity, has a small pressure loss even when it is transferred by a pump or the like, and is prevented from adhering and depositing on the inner surface of the pipe.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a method for producing a clathrate hydrate slurry used as a cold heat source of, for example, an air conditioner.
As shown in FIG. 1, a heat storage tank 1 for producing a clathrate hydrate slurry is constituted by an open-to-atmosphere container 3 having an opening 2 on an upper part, and forms a clathrate hydrate when cooled inside. The aqueous solution W is stored.

The aqueous solution W is any one of a tetra-n-butylammonium salt, a tetra-iso-aluminum ammonium salt, a tetra-n-butylphosphonium salt, and a tri-isoaluminosulfonium salt. A substance having a lower freezing point, for example, a glycol-based antifreeze may be added.

An evaporator 5 constituting a refrigeration unit 4 is installed inside the container 3 of the heat storage tank 1. This evaporator 5
The copper pipe 5a is bent in a meandering shape, and a refrigerant inlet 5b is provided at one end and a refrigerant outlet 5c is provided at the other end. In the refrigerating apparatus 4, a compressor 6, a condenser 7, a liquid receiver 8, an expansion valve 9, and the evaporator 5 are connected in this order by a refrigerant pipe 10, and the expansion valve 9 and the refrigerant inlet 5 of the copper pipe 5a are connected.
b is connected, the suction side of the compressor 6 is connected to the refrigerant outlet 5c, and constitutes a known refrigeration cycle.

The aqueous solution W in the heat storage tank 1 is cooled by evaporating the refrigerant in the evaporator 5 in the heat storage tank 1, and the aqueous solution W is cooled to form the clathrate hydrate slurry W1. The generated clathrate hydrate slurry W1 is a copper tube 5a.
So that it adheres to the surface.

The attached hydrate is separated from the surface of the evaporator 5 by physical or thermal means and dispersed in the solution.
As a physical means, there is a method of periodically applying vibration to the evaporator pipe in the heat storage tank. The surface portion of the hydrate adhered is separated and dispersed in the aqueous solution to form a slurry. Also,
As the thermal means, a high-temperature refrigerant flows through the evaporator piping by periodically switching the cooling piping route. When using this method, it is preferable to attach curtain-shaped fins to the cooling pipe. When the high-temperature refrigerant flows through the cooling pipe, the fin portion is heated, and the deposits on the fin surface portion are melted, fall into the tank, and mix with the solution to form a slurry.

The heat storage tank 1 is provided with a supply pipe 11 and a return pipe 12 for supplying the generated clathrate hydrate slurry W1, and a heat storage medium circulating system 13 for circulating the clathrate hydrate slurry W1. Is composed. The clathrate hydrate slurry W1 in the heat storage tank 1 is sent to a heat load side (not shown) of an air conditioner or the like and used as a cold heat source.

Next, a method for producing the clathrate hydrate slurry configured as described above will be described. When the aqueous solution W is stored in the heat storage tank 1 and the refrigerating device 4 is operated, the compressor 6
The high-temperature and high-pressure refrigerant compressed by the condenser is condensed by the condenser 7 to become a liquefied refrigerant. The liquefied refrigerant is guided to the expansion valve 9 via the liquid receiver 8, where the pressure is reduced, and then guided to the evaporator 5. Since the refrigerant takes away the heat around the copper tube 5a and evaporates, the aqueous solution W in the heat storage tank 1 is cooled, clathrate hydrate is generated, and adheres to the surface of the copper tube 5a of the evaporator 5, and By peeling, the solid is dispersed in the solution to form a sherbet-shaped clathrate hydrate slurry W1. In addition, the clathrate hydrate slurry W1 is sent to a heat load side such as an air conditioner via the supply pipe 11, and is used as a cold heat source.

The cooling temperature for producing the clathrate hydrate slurry W1 can be water of 0 ° C. or higher, and is not limited to the refrigeration cycle described above.
Cold water may be circulated through a, the coefficient of performance of the refrigeration system can be increased, and energy can be saved.

As described above, by using the heat storage medium that easily forms clathrate hydrate even under atmospheric pressure, the global environment such as ozone destruction and the like can be reduced as in the case of using the conventional fluorocarbon refrigerant R11. Eliminate problems.

[0023]

As described above, according to the first to fourth aspects of the present invention, the clathrate hydrate is produced by evaporating the refrigerant by the evaporator in the heat storage tank and cooling the aqueous solution. The solid adheres to the surface of the evaporator and peels off to disperse the solids in the solution, whereby a sherbet-like clathrate hydrate slurry can be produced. Therefore, high-density cold heat transport to the cooling load is possible. Also, it takes 0 to cool the clathrate hydrate.
Since it is possible to use chilled water of at least ℃, the coefficient of performance of the refrigeration system can be increased, and energy can be saved. In addition, clathrate hydrates can be easily produced even under atmospheric pressure, and there is no need for a closed container as in the related art, so that there is an effect that the apparatus can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a method for producing a clathrate hydrate slurry according to a first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermal storage tank 4 ... Refrigerator 5 ... Evaporator W ... Aqueous solution W1 ... Clathrate hydrate slurry

Claims (4)

[Claims] An aqueous solution that generates a clathrate hydrate when cooled is stored in a heat storage tank, an evaporator constituting a refrigerating device is installed in the heat storage tank, and a refrigerant is evaporated by the evaporator. A method for producing a clathrate hydrate slurry, comprising cooling the aqueous solution and causing the clathrate hydrate slurry to adhere to the evaporator. 2. The aqueous solution according to claim 1, wherein the aqueous solution is one of a tetra-n-butylammonium salt, a tetra-iso-aluminum ammonium salt, a tetra-n-butylphosphonium salt, and a tri-isoaluminosulfonium salt. Item 10. A method for producing a clathrate hydrate slurry according to Item 1. 3. The method for producing a clathrate hydrate slurry according to claim 1, wherein a substance having a lower freezing point than water is added to said aqueous solution. 4. The method for producing a clathrate hydrate slurry according to claim 1, wherein the evaporator is a meanderingly bent copper tube disposed inside a heat storage tank.