JPS5913512Y2 - heat storage device - Google Patents

Description

[Detailed description of the invention] This invention relates to a heat storage device, and more specifically, a heat storage tank using a metal, an alloy, or a hydride thereof as a heat storage material and a hydrogen storage tank are connected by a hydrogen flow pipe via an on-off valve. In this heat storage device, a heat storage material tank made of a material having pores through which hydrogen gas can pass is provided in the heat storage tank, and a heat exchange part of a heat medium transport pipe is installed inside the heat storage material tank, and the heat storage The space formed between the inner wall surface of the tank and the outer wall surface of the heat storage material tank is filled with a heat insulating material through which hydrogen gas can pass, and the hydrogen flow pipe is opened [1].
The present invention relates to a heat storage device including a heat insulating material filling portion.

Conventionally, various thermal energy storage devices have been developed and studied. Na2SO4・5H20,Na2
Methods using latent heat due to hydrated salts such as SO4.10H20 are also being researched.

However, both have problems with heat retention, and even if the heat storage tank is made of a material with excellent heat insulation effect, it dissipates a considerable amount of thermal energy, so the heat storage effect is poor and it can only be used for short-term heat storage.

By the way, as a heat storage method that compensates for the above drawbacks,
Heat storage methods using metals, alloys, or their hydrides as heat storage materials (for example, Osamu Ono, chemistry field,
■O1, 31, NO1, 1st. -47, 1977) was proposed.

This heat storage method uses a metal, an alloy, or a hydride thereof that can undergo hydrogenation and dehydrogenation reactions reversibly, and stores heat and extracts energy through a reaction represented by the following formula.

MHx→M×Hx (endothermic reaction: heat storage process) M+Hx−+
MHx (exothermic reaction: heat dissipation process) where M is a metal or alloy, H is a hydrogen atom, and X is the number of hydrogen atoms.

This heat storage method is expected to be an innovative method for long-term heat storage, and intensive research is underway.

First, a typical example of a heat storage device using this method will be given, and the operating method of the device will be explained with reference to the drawings.

That is, in FIG. 1, for example, a heat medium that collects solar heat is guided to a heat storage tank 5 by a heat medium transport pipe 3, and the heat is used to transform the metal or alloy hydride constituting the heat storage material 7 in the heat storage tank 5. Dehydrogenate by heating.

The generated hydrogen gas is transferred to the hydrogen storage tank 1 by opening the valve 2 and passing it through the hydrogen distribution pipe 4 (however, the part inside the heat storage tank is a mesh pipe).
sent to and stored.

Next, when it is desired to utilize heat, the valve 2 is opened to introduce hydrogen gas into the heat storage tank 5, and during the heat exchange, the heat storage material 7 in which the metal or alloy hydride is dehydrogenated and converted into a metal or alloy.
and hydrogen, and the generated heat is collected by the heat medium in the heat medium transport pipe 3 and used for heating and cooling, hot water supply, etc.

Note that 6 is a heat insulating material that constitutes the heat storage tank 5, and of course hydrogen gas cannot pass therethrough.

The present invention relates to an improvement of such a conventional heat storage device, and has been made for the purpose of improving the thermal efficiency of this heat storage tank and simplifying its structure to reduce equipment costs.

The structural features and effects of this invention are as follows.

That is, a heat storage material tank made of a material having pores through which hydrogen gas can pass and filled with the heat storage material as described above is provided inside the heat storage tank, and the hydrogen gas flows through its outer wall to either the inside or outside of the heat storage material tank. It is also movable.

Furthermore, since the space between the inner wall of the heat storage tank and the outer wall of the heat storage material tank is filled with a heat insulating material that allows hydrogen gas to pass through, this layer of heat insulating material insulates the heat storage material tank. It also functions as a hydrogen flow path, allowing hydrogen gas to flow between both layers of the insulation material and heat storage material, thereby eliminating the need to introduce hydrogen flow pipes inside the heat storage material as in the past. By simply opening the heat insulating layer, hydrogen gas can flow in both directions into and out of the heat storage tank.

Therefore, there is no need for the complicated and expensive hydrogen flow pipes that come into direct contact with the heat storage material, such as the mesh pipes in the conventional heat storage tank, resulting in lower cost and the volume of the heat storage tank per unit weight of the heat storage material. The structure is simplified and the thermal efficiency is significantly improved.

The heat storage material tank in this invention may be made of any material that allows hydrogen gas to pass through, and examples thereof include mesh stainless steel, but are not particularly limited.

Further, the heat insulating material may be any material as long as it does not react with hydrogen gas, can be filled in a manner allowing hydrogen gas to pass therethrough, and exhibits a heat insulating effect.

Examples include diatomaceous earth or molecular sieve.

Furthermore, as a heat storage material, LaNi5 or CaxNiM
An appropriate material such as ml-x (Mm: mesh metal) can be used.

Hereinafter, the heat storage device of the present invention will be explained with reference to an embodiment shown in FIG.

The heat storage tank 12 of this embodiment is cylindrical, 260 mm high x 240 mmφ, and 2 mm thick stainless steel (SUS 3).
16), and the heat storage material tank 16 provided inside is cylindrical with an internal volume of 41 cm, and has a height of 200 mm and a height of 160 mm.
mmφ, 2mm thick 325 mesh stainless steel (SL
TS 316).

In this heat storage material tank 16, there are 48 mesh paths of LaNi5.
61 kg of H was filled.

The heat medium flow pipe 10 is a heat pipe (3 mmφ, SU
S 316 ) was used.

A space formed between the heat storage material tank wall 15 and the heat storage tank wall 17 is filled with diatomaceous earth that does not react with hydrogen gas as a heat insulating material 13 so that hydrogen gas can pass therethrough.

The hydrogen storage tank 8 was a pressure-resistant container capable of storing 2001 hydrogen gas.

On the other hand, the hydrogen flow pipe 4 of the conventional heat storage device shown in FIG.
The inside of the heat storage tank 5 is constructed of an expensive mesh pipe, whereas the hydrogen flow pipe 11 of the embodiment of the present invention is connected to the heat storage tank 12 and is only opened in the heat insulating material 13 of the heat storage tank 5. It is almost unnecessary in the tank.

In other words, hydrogen gas flows through the heat insulating material 13 within the heat storage tank 12, and the insulating material 13 also serves as a flow path for the hydrogen gas.

According to the device of the above embodiment, the volume of the heat storage tank per unit weight of the heat storage material is 1
It has been reduced by 0 to 20%, the structure has been simplified, and the thermal efficiency has been significantly improved.

On the other hand, in the heat storage device of this embodiment, if hydrogen were to leak from the hydrogen flow pipe 11 between the hydrogen storage tank 8 and the heat storage tank 12, air would be mixed into the heat storage device.

In general, the metal or alloy of the heat storage material 14 combines with oxygen in the air to form a metal oxide, suppresses the hydrogenation reaction of the metal or alloy, acts as a catalyst poison, and further promotes hydrogenation and dehydrogenation. This also reduces the reversibility of heat storage and reduces the heat storage function of the heat storage device.

Further, there is no problem if the hydrogen gas in the hydrogen storage tank 8 and the heat storage tank 12 is in a pressurized state, but if the hydrogen gas leaks, the hydrogen in the heat storage device will decrease.

In this case, if you want to continue the heat storage cycle with the same heat storage capacity, it is necessary to fill up the hydrogen shortage from the outside.

Furthermore, hydrogen becomes highly purified when hydrogenation and dehydrogenation reactions are repeated through repeated heat storage cycles, so in order to maintain the same level of heat storage performance, it is necessary to supply hydrogen with the same level of purity. Moreover, since the metals or alloys mentioned above are sensitive to oxygen, the purity of hydrogen with little oxygen content is 99.99999%, and the oxygen content is 0.
It must be high purity hydrogen with O5 ppm or less.

The problem of hydrogen gas leakage as described above can be solved, for example, by connecting the high-purity hydrogen supply tank 18 to the hydrogen flow pipe 11 via the on-off valve 19 in the apparatus shown in FIG. 2, which is preferable.

That is, a high-purity hydrogen supply tank 18 (within the dashed line section in Figure 2) made of stainless steel (SUS 316) with a cylindrical shape, height 200 mm x 4Q mmφ, and thickness 2 mm is connected to the hydrogen flow pipe 1.
1 through valve 19, and 200 g of LaN15Hs.
filled with.

When detecting the hydrogen gas pressure in the hydrogen flow pipe 11 and discovering that hydrogen gas has leaked from the hydrogen flow pipe 11 between the hydrogen storage tank 8 and the heat storage tank 12, the valve 19 of the high-purity hydrogen supply tank 18 is opened. Then, high-purity hydrogen gas is added into the hydrogen flow pipe 11.

Specifically, after repeatedly opening and closing the valves 21 and 19 to replace the inside of the hydrogen flow pipe 11 with high-purity hydrogen gas, the hydrogen gas pressure inside the pipe is adjusted to the pressure at the end of the heat storage cycle, and the next heat storage cycle is started. carried out.

In addition, the high-purity hydrogen source in this high-purity hydrogen supply tank is
In addition to the LaNi5H6, other suitable metal hydrides or high purity hydrogen gas can be used.

When hydrogen gas leaked while repeating the heat storage cycle in the above device, the amount of reaction heat per unit weight of the heat storage material was compared between when hydrogen gas was added and when it was not added, as shown in Figure 3.

Continuing the heat storage cycle while supplying high-purity hydrogen gas prevents oxygen from entering the heat storage device, thereby preventing deterioration of heat storage performance, so supplying high-purity hydrogen has industrial value. It turned out to be large.

[Brief explanation of the drawing]

Fig. 1 is a functional explanatory diagram of a conventional heat storage device, Fig. 2 is a functional explanatory diagram including a partially cutaway diagram showing an embodiment of the heat storage device of the present invention, and Fig. 3 is a functional explanatory diagram showing the number of heat storage cycles in the heat storage device. It is a graph showing the relationship between and the reaction heat amount (Kcal/kgLaNi5), where A shows the case where high purity hydrogen is supplied and the hydrogen gas pressure is adjusted, and B shows the case where the hydrogen gas pressure is not adjusted. 1 and 8...Hydrogen storage tank, 2, 9, 19.2
0 and 21...Open/close valve, 3 and 10...
... Heat medium flow pipe, 4 and 11 ... Hydrogen gas flow pipe, 5 and 12 ... Heat storage tank, 6 ...
... Insulation material, 7 and 14 ... Heat storage material, 13
...Insulating material that also serves as a flow path for hydrogen gas, 15...
... Heat storage material tank wall, 16 ... Heat storage material tank, 17
. . . Heat storage tank wall and 18 . . . High purity hydrogen supply tank.

Claims (1)

[Scope of utility model registration request] A heat storage device in which a heat storage tank and a hydrogen storage tank are connected by a hydrogen flow pipe via an on-off valve, and the heat storage tank includes a heat storage material tank made of a material that has pores through which hydrogen gas can pass. established,
A heat storage material tank is filled with a heat storage material made of a metal, an alloy, or a hydride thereof, and a heat exchange section of a heat medium transport pipe is installed inside the heat storage material tank, and is configured between the inner wall surface of the heat storage tank and the outer wall surface of the heat storage material tank. A heat storage device comprising a space filled with a heat insulating material through which hydrogen gas can pass, and an opening for a hydrogen flow pipe provided in the heat insulating material filled part.