JP2003302181A - Heat accumulating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat accumulating device capable of preventing a reaction of water as a heat exchange medium with a heat accumulating material when a heat exchanger tube is broken. <P>SOLUTION: The heat accumulating material 13 consisting of magnesia and nitrates is housed in a vessel 12, in which also the heat exchanger tube 14 is housed. The heat exchanger tube 14 is composed of an outer pipe 21 and an inner pipe 22, and a gap 23 is formed between the two pipes 21 and 22. A part of the heat exchanger tube 14 is exposed to upward penetrating a lid 12b of the vessel 12. The opening 25 of the gap 23 is formed in the exposed portion 14a, and a temperature sensor 26 is installed so as to correspond to the opening 25. When the inner pipe 22 is broken, the vapor in it is passed through the gap 23 and emitted to the outside from the opening 25. The temperature sensor 26 detects the vapor and informs about breakage of the inner pipe 22. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage device that stores heat in a substance having a large specific heat and uses the sensible heat later.

[0002]

2. Description of the Related Art The following heat storage device has been known. That is, the container of the heat storage device is filled with a heat storage material composed of solid magnesia and a nitrate that liquefies in a predetermined heat storage temperature range. A heater for heating the heat storage material and a heat transfer tube are embedded in the heat storage material. The heat storage material in the container is heated by a heater using late-night power or the like to store heat. By supplying water from one of the heat transfer tubes in this state, the water exchanges heat with the heat storage material, and high-temperature steam is taken out from the other of the heat transfer tubes.

[0003]

However, the conventional heat storage device has the following problems. That is, since the heat transfer tube is formed of a single tube made of stainless steel, corrosion resistance to the nitrates constituting the heat storage material is secured, but the heat transfer tube is damaged by stress corrosion due to chlorine ions contained in tap water. There was a problem of doing. When the heat transfer tube is damaged, tap water flows out into the heat storage material as a heat exchange medium, is jetted out of the container as water vapor, nitrates enter the heat transfer tube, and the nitrates are mixed in the taken out steam. In addition, leakage of the supply water may cause various problems such as reduction in the amount of heat taken out.

Further, since the heat transfer tube is embedded in the heat storage material, the heat transfer tube cannot be easily replaced, and once the accident of the heat transfer tube occurs, it is very difficult to repair the heat storage device.

In order to prevent such a problem from occurring, an ion exchange device for removing chlorine ions in tap water has been conventionally used. However, there is a problem that the initial cost and running cost of the ion exchange device are high and the cost of the heat storage device as a whole cannot be reduced.

The object of the present invention is to prevent problems such as the heat exchange medium penetrating into the heat storage material to become vapor when the heat transfer tube is broken and the vapor is jetted out of the container. It is to provide a heat storage device.

Another object of the present invention is to provide a heat storage device capable of easily detecting breakage of a heat transfer tube in addition to the above object. Another object of the present invention is to provide a heat storage device capable of preventing the heat storage material from coming into contact with supply water due to breakage of the heat transfer tube.

Another object of the present invention is to provide a heat storage device which can use soft water as a heat exchange medium and can reduce the cost by eliminating the need for an expensive ion exchange device.

[0009]

In order to solve the above-mentioned problems, the invention as set forth in claim 1 stores a heat storage material in a container and a heat transfer tube and a heating means in the container,
The gist is that the heat transfer tube has a double structure of an outer tube and an inner tube.

According to a second aspect of the present invention, in the first aspect, a part of the heat transfer tube is used for detecting an abnormality in the inner tube from a steam discharged through a gap between the outer tube and the inner tube. The point is that a sensor is provided.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the above, the outer tube and the inner tube are made of different materials, and the outer tube is made of a corrosion-resistant material such as austenitic stainless steel or nickel alloy having corrosion resistance to the heat storage material, and the inner tube is the inner tube. The gist is that it is made of a corrosion-resistant material such as soft iron, copper, a steel pipe for a boiler, and a ferritic stainless steel, which has a corrosion resistance to the heat exchange medium passing therethrough.

The invention according to claim 4 is the invention according to claim 2 or 3.
A part of the heat transfer tube is exposed to the outside of the heat storage material and is led out, a part of the outer tube is removed to form an exposed portion of the inner tube, and the sensor is provided corresponding to the exposed portion. What is done is the gist.

A fifth aspect of the present invention is, in any one of the first to fourth aspects, characterized in that a container for heating means is housed in the container. A sixth aspect of the present invention is, in any one of the first to fourth aspects, characterized in that a container for the heat transfer tube is housed in the container.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a heat storage device embodying the present invention will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, the heat storage device 11
The container 12 includes a container body 12a having an open top and a lid 12b attached to an upper opening of the container body 12a. The container body 12a is filled with a heat storage material 13 (only part of which is shown in FIGS. 1 and 2) containing magnesia and nitrate as main components, and water as a heat exchange medium is circulated inside. A heat transfer tube 14 is provided.

The heat transfer tubes 14 are formed by arranging a plurality of meandering tubes in parallel so that the intervals between them are uniform and connecting them in series. The surface area of the heat transfer tube 14 per unit volume of the heat storage material 13 is substantially equal in each part in the container body 12a. Both ends of the heat transfer tube 14 extend through the lid 12b to the outside.

As shown in FIGS. 1 and 2, the container body 12
In a, a plurality of heater accommodating containers 15 are embedded between the meandering portions of the heat transfer tube 14. Heater container 1
Reference numeral 5 is made of a metallic material having a heat conductivity such as stainless steel, and is formed in a bottomed cylindrical shape having an open top. Each heater housing 15 is arranged so that the heat storage material is heated as uniformly as possible. The upper opening of the heater housing 15 has heaters 16a to
16f is a heater insertion port 15a into which
The heaters 16a to 16f project from the upper surface of the lid 12b.

As shown in FIGS. 2 and 3, each heater accommodating container 15 accommodates a plurality of meandering heaters 16a to 16f. In addition, each heater housing container 15 is filled with a nitrate, so that the inner surface of each heater housing container 15 and the heaters 16a to 16a-1.
The gap with 6f is filled.

The heater container 15 includes a heater 16a.
A heater isolation structure that prevents contact between the heat storage material 13 to 16f and the heat storage material 13 is configured. Further, the heater housing container 15 is used for each heater 1.
It functions as a partition wall that covers at least the periphery of the heat storage material embedding portion 6a to 16f. The nitrate that constitutes the heat storage material 13 functions as a heat storage medium inside the heater housing container 15.

Next, the structure of the essential parts of the present invention will be described. The heat transfer tube 14 is an outer tube 21 made of stainless steel, and an inner tube 2 made of soft iron and penetrating inside the outer tube 21.
And 2 form a double structure. The outer tube 21
The inner tube 22 and the inner tube 22 are manufactured so as to have a design for forming a minute gap in manufacturing the heat transfer tube in consideration of a difference in thermal expansion during use. The formation of the gap 23 during use functions as a steam passage through which the soft water as the heat exchange medium evaporates by heating to become steam when the inner pipe 22 is damaged.

As shown in FIG. 1, the heat transfer tube 14 is exposed to the outside of the heat storage material 13 via the lid 12b at the middle portion thereof, and a part of the outer tube 21 of the exposed portion 14a is removed. The inner pipe 22 is exposed. Then, the abutting end edges of the inner pipe 22 are welded to each other to form the connection connecting portion 24. Further, a temperature sensor 26 as a sensor for detecting an abnormality is provided in the vicinity of the gap opening 25 between the exposed surface 22a of the inner pipe 22 and the inner surface 21a of the outer pipe 21 formed by the difference in the coefficient of thermal expansion. It is arranged. Then, when the inner pipe 22 is damaged, the steam heated passes through the gap 23,
When the steam is discharged from the gap opening 25, the temperature of the steam is sensed and the temperature sensor 26 is activated to report an abnormality such as a crack in the inner pipe 22.

(Operation of Embodiment) Next, the operation of the heat storage device 11 configured as described above will be described. When heat is stored in the heat storage material 13, the heaters 16a to 16f are energized to generate heat. Then, the heat emitted from each of the heaters 16a to 16f is efficiently conducted to the heat storage material 13 via the nitrate filled in each heater accommodating container 15 and each heater accommodating container 15.

Incidentally, when the heater accommodating container 15 is not filled with nitrate, a gap is formed between the inner surface of the heater accommodating container 15 and each of the heaters 16a to 16f, and the heat generated from each of the heaters 16a to 16f is generated. Heater container 15
It is not efficiently transmitted to the heat storage material 13 outside. In addition, each of the heaters 16a to 16f is in an empty state.

If, for example, the heater 16a among the heaters 16a to 16f fails for some reason, this heater 1
6a is replaced as follows. That is, the other normal heaters 16b to 16f are energized and heated to raise the temperature of the heat storage material 13 to about 140 ° C. at which the nitrate liquefies. With the nitrate liquefied, the defective heater 16a is pulled out from the heater housing container 15 and another normal heater is inserted.

Since each of the heaters 16a to 16f is housed in the heater housing container 15, each heater 16a
.About.16f and the solid-state magnesia forming the heat storage material 13 do not come into direct contact with each other. Further, since the nitrate is liquefied, a large frictional resistance does not act on the heaters 16a to 16f. Therefore, each of the heaters 16a-16
It is easy to insert / remove f into / from the heater container 15 (strictly speaking, into the molten nitrate). Therefore, each heater 1
Unlike the case where 6a to 16f are directly buried in the heat storage material 13, the replacement work of each heater 16a to 16f becomes easy.

(Effects of Embodiment) Therefore, according to this embodiment, the following effects can be obtained. (1) Since the heat transfer tube 14 is composed of the outer tube 21 and the inner tube 22 and the gap 23 is formed between them, for example, in a case where the inner tube 22 is damaged by the water supplied to the inner tube 22 In addition, the heated steam is retained in the gap 23. Therefore, it is possible to prevent the contact between the nitrate that constitutes the heat storage material 13 and the water. As a result, there is no possibility that the nitrate flows out into the heat storage material, is jetted out of the container as water vapor, nitrate enters the heat transfer tube, and the nitrate is not mixed into the taken out steam.

(2) A part of the heat transfer tube 14 is replaced with the heat storage material 13
The exposed portion 1 is exposed upward through the lid 12b.
4a of the outer pipe 21 is removed to expose the inner pipe 22,
A temperature sensor 26 is provided in the vicinity of the gap opening 25 between the surface 22 a of the inner pipe 22 and the inner surface 21 a of the outer pipe 21. Therefore, when the inner pipe 22 is damaged and water vapor enters the gap 23, the water vapor is detected by the temperature sensor 26, and it is possible to easily detect that an abnormality has occurred in the inner pipe 22.

(3) The outer pipe 21 is made of a stainless steel material excellent in corrosion resistance to nitrates, and the inner pipe 22 is made of soft iron which does not cause stress corrosion cracking due to chlorine ions contained in ordinary tap water. . Therefore, normal tap water can be used as it is as the heat exchange medium, an expensive ion exchange device need not be used, and the cost of the heat storage device can be reduced.

(4) Each heater 16 is provided in the container 12.
A heater isolation structure is provided to prevent contact between a to 16f and the heat storage material 13. That is, a plurality of heater accommodating containers 15 are embedded in the heat storage material 13, and each heater 1 is accommodated in each heater accommodating container 15.
6a to 16f are accommodated. Therefore, the contact between the heaters 16a to 16f and the magnesia (solid content) forming the heat storage material 13 is prevented. Each heater 16a-1
Since there is no friction between 6f and the heat storage material 13, each heater 16a
~ 16f is easy to attach and detach, and each heater 16a ~ 16f
Can be easily replaced. Further, it is not necessary to dispose a spare heater in case of failure, and the cost increase of the heat storage device 11 can be suppressed. Furthermore, since the heaters 16a to 16f do not come into direct contact with magnesia, it is possible to prevent the heaters 16a to 16f from being damaged.

(5) The location of the temperature sensor 26 is
As shown in FIG. 1, the connecting / connecting portion 24 of the heat transfer tube 14, which is required in the assembling work, is also used. By disposing the temperature sensor 26 in correspondence with the gap opening 25 exposed for the connection, the inner pipe 22 can be easily
An abnormality sensor (detection unit) can be provided.

(Other Example) The above embodiment may be modified as follows. As shown in FIG. 3, the container 12 is formed in a bottomed cylindrical shape, and the heater housing container 15 is also formed in a bottomed elliptic cylindrical shape. Further, the heat transfer tube 14 is housed in a spiral shape between the container 12 and the heater housing container 15. The heat transfer lead-out portion 14c of the heat transfer tube 14 is provided with a clearance opening 25 communicating with the clearance 23, and the temperature sensor 2 corresponds to the clearance opening 25.
6 is provided.

As shown in the horizontal cross section of FIG. 4, a heat transfer tube storage container 31 different from the heater storage container 15 may be stored in the container 12. The heat transfer tube housing container 31 is filled with only nitrate as a heat storage material. In this another example, the heat transfer tube 1
If 4 is damaged, heat transfer tube 1
4 can be easily replaced.

The heater 16 may be housed in the heat transfer tube housing container 31 as shown in the horizontal cross section of FIG. As shown in FIG. 6, the outer surface of the inner tube 22 is plated with a material having high corrosion resistance to nitrate such as nickel to form the outer layer 21 ′, and the heat transfer tube 14 may have a two-layer structure. Good.

As shown in FIG. 7, an inner layer 22 ′ made of a corrosion-resistant material such as iron or copper having good corrosion resistance to soft water is plated on the inner peripheral surface of the outer tube 21 made of stainless steel. The heat transfer tube 14 may have a two-layer structure.

In the above-mentioned another example, damage to the heat transfer tube can be prevented in advance. In the above embodiment, the temperature sensor 26 detects the temperature of the leaked steam from the gap 23, but a sensor for detecting the humidity, conductivity, leak current or the like of the steam may be used.

In the present embodiment, the heater housing container 15
Although the nitrate is filled in the inside or the heat transfer tube housing container 31, it may be filled with another heat storage medium (for example, heat transfer oil). Even in this way, each heater 16a
The heat of 16 f is efficiently conducted to the heat storage material 13 via the heat storage medium in the heater housing container 15 and the heater housing container 15. Further, when an organic heat transfer oil is used, it is not necessary to raise the temperature when replacing the heater because it is liquid even at room temperature.

In each of the above-described embodiments, the outer pipe is made of stainless steel and the inner pipe is made of soft iron. However, the present invention is not limited to this, and any corrosion-resistant material of the gist of the present application may be used. The tube may be austenitic stainless steel or nickel alloy. Further, the inner pipe may be appropriately selected and changed to copper, steel pipe for boiler, ferritic stainless steel or the like.

[0038]

As described in detail above, according to the first aspect of the present invention, when the inner pipe is damaged, it is possible to prevent the heat exchange medium flowing inside the inner pipe from reacting with the high heat storage material. it can.

In the second aspect of the invention, the abnormality of the inner tube can be easily detected by the sensor. Claim 3
The invention described in (1) can prevent the outer pipe from being corroded by the heat storage material, and can prevent the inner pipe from being corroded by the heat exchange medium flowing in the inner pipe. Further, ordinary tap water, soft water, etc. can be used as the heat exchange medium, and it is not necessary to provide an expensive ion exchange device.

According to the invention described in claim 4, the sensor can be easily installed. The invention according to claim 5 is
When the heating means is damaged, the replacement work can be easily performed.

According to the sixth aspect of the invention, when the heat transfer tube is damaged, the replacement work can be easily performed.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view of a heat storage device according to this embodiment.

FIG. 2 is a plan sectional view of a heat storage device according to the present embodiment.

FIG. 3 is a perspective view of a heat storage device according to another embodiment.

FIG. 4 is a plan sectional view of a heat storage device according to another embodiment.

FIG. 5 is a plan sectional view of a heat storage device according to another embodiment.

FIG. 6 is a partial cross-sectional view showing another example of the heat transfer tube.

FIG. 7 is a partial cross-sectional view showing another example of the heat transfer tube.

[Explanation of symbols]

12 ... Container, 13 ... Heat storage material, 14 ... Heat transfer tube, 21 ... Outer tube, 22 ... Inner tube, 23 ... Gap, 25 ... Opening part.

Continued front page    (72) Inventor Wataru Nagao             Energy, No. 1, Upper Hand, Inuyama, Aichi Prefecture             Port Co., Ltd. F-term (reference) 3L103 AA12 AA13 AA27 BB50 CC02                       CC40 DD05 DD06 DD38 DD82

Claims (6)

[Claims] 1. A heat storage device in which a heat storage material is housed in a container, a heat transfer tube and a heating means are housed in the container, and the heat transfer tube has a double structure of an outer tube and an inner tube. 2. The sensor according to claim 1, wherein a part of the heat transfer tube is provided with a sensor for detecting an abnormality in the inner tube from a steam released through a gap between the outer tube and the inner tube. Heat storage device. 3. The corrosion resistant material according to claim 1, wherein the outer tube and the inner tube are made of different materials, and the outer tube has corrosion resistance to the heat storage material, such as austenitic stainless steel and nickel alloy. The inner tube is made of, for example, soft iron having corrosion resistance to the heat exchange medium passing through the inner tube,
A heat storage device made of corrosion resistant materials such as copper, steel pipes for boilers, and ferritic stainless steel. 4. The heat transfer tube according to claim 2, wherein a part of the heat transfer tube is exposed outside the heat storage material and is led out, and a part of the outer tube is removed to form an exposed part of the inner tube. A heat storage device in which the sensor is provided corresponding to the exposed portion. 5. The method according to any one of claims 1 to 4,
A heat storage device in which a container for heating means is housed in the container. 6. The method according to any one of claims 1 to 4,
A heat storage device in which a container for the heat transfer tube is housed in the container.