JPS6121272B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat storage material. For more details,
This invention relates to a heat storage material that utilizes thermal energy such as solar heat, and uses CaNi ₅ alloy hydride or its alloy as the heat storage system (high temperature side) and CaNi 5 alloy hydride (CaxMm ₁ -xNi ₅ alloy hydride) as one storage system (low temperature side). However, Mm in the formula is Mitsushi Metal, x is 0.8
- 0.9)). Furthermore, according to this invention, the CaNi ₅ alloy hydride in the heat storage system is dehydrogenated using thermal energy such as solar heat, and the generated hydrogen is used to dehydrogenate the CaNi ₅ alloy hydride in the storage system.
-xNi ₅ alloy (Mm and x in the formula have the same meanings as above) When you want to store and use heat by hydrogenating it, use a heat storage alloy that can be hydrogenated at low temperatures, or a storage alloy. The present invention provides a heat storage method comprising hydrogenating a hydride with hydrogen generated and utilizing the generated reaction heat, and a heat storage tank thereof. In the past, various methods of storing thermal energy have been considered and studied. For example, there are methods that utilize the sensible heat of water, rocks, etc. to store the thermal energy of solar heat, and recently, methods other than sensible heat, such as
Methods using latent heat from hydrated salts such as Na ₂ SO ₄ , 5H ₂ O, Na ₂ SO ₄ .1CH ₂ O, etc. are also being studied. However, both require heat insulating material, and even if the heat storage tank is made of a material with excellent heat insulating properties, it radiates a considerable amount of energy, so the heat storage effect is inferior, and it can only be used for short-term heat storage. By the way, as a heat storage method that does not require insulation as described above, there is a heat storage method using metals, alloys, or their hydrides as heat storage materials (for example, Shuichiro Ono, Chemistry Area, Vol. 31, No. 1, p. 39). ~47
Page, 1977) has been proposed. Although this method is expected to be an innovative method for long-term heat storage, there are almost no practical and concrete examples of studies. In this heat storage method, the heat storage metal or alloy has a large hydrogenation reaction heat of 80℃~
It is possible to perform dehydrogenation at around 100℃ and hydrogenation at room temperature, and it also has low cost, large hydrogen storage capacity, and easy to control hydrogen gas pressure (10Kg/cm ² or less; hydrogenation and dehydrogenation are possible. (meaning that it can be carried out at a pressure lower than the pressure shown on the left) is desirable. On the other hand, as storage metals or alloys, the heat of reaction does not need to be large, and the hydrogen gas pressure needs to be hydrogenated near room temperature, low cost, and have a large hydrogen storage capacity, as well as easy to control hydrogen gas pressure (10 kg/cm ² or less). desired. As a heat storage material that meets these requirements
Combinations of alloys such as LaNi ₅ , FeTi, and MmmNi ₅ are considered to be relatively promising. However, LaNi ₅ is expensive, and although FeTi is cheap, it is difficult to rehydrogenate it if left in the air, and there are problems in its handling. Masa MmNi ₅ is attracting attention as a replacement of expensive La with inexpensive Mitsushi metal, but its plateau pressure is 30Kg/cm ² (25℃) to 50Kg/cm ² (60
℃), which makes it difficult to handle due to the pressure, which poses a problem for practical use. In order to eliminate the drawbacks of the heat storage method using an alloy hydride or its alloy as a heat storage material as described above, the present inventors conducted extensive research and arrived at the present invention. That is, the feature of the heat storage material of this invention is that CaNi ₅ alloy hydride or its alloy is used as the heat storage system, and CaxMm ₁ -xNi ₅ hydride is used as the storage system (where Mm is Mitsushimetal and x is a value between 0.8 and 0.9. meaning) or a combination of their alloys. The CaNi ₅ alloy for the heat storage system of this invention is inexpensive;
(Cheaper than LaNi ₅ , equivalent to FeTi, MmNi ₅ ) Hydrogenation reaction heat is similar to LaNi ₅ (7.6 Kcal/molH ₂ ), and plateau pressure is low (3.5 Kg/cm ² at 80°C,
0.5Kg/cm ² ) at 25°C, it has characteristics such as being relatively easy to handle and easy to activate. On the other hand, storage system
The CaxMm ₁ -xNi ₅ alloy has a plateau pressure at high temperature that is higher than the CaNi ₅ alloy's plateau pressure at 25°C of 0.5 Kg/cm ² , especially when x is 0.8 to 0.9, but the CaNi ₅ alloy's plateau pressure at 80°C is 3.5Kg/ ^cm2 and relatively cheap (the price of this alloy is lower than CaNi ₅
Although it is more expensive by the amount of Mm, it has characteristics such as being not much different from CaNi ₅ because the Mm content is small. These alloys were developed in 1977 in the District of Columbia by Sandrock G.D.
The 12th event was held from August 28th to September 2nd.
Reference is made to IECEC meeting minutes, pages 951-958. Table 1 shows the reaction temperature and plateau pressure (dissociation pressure) of CaNi ₅ alloy and CaxMm ₁ -xNi ₅ alloy.

[Table] Next, the present invention will be explained in detail using FIGS. 1 to 3. First, as an example in FIG. 1, the heat exchange medium 5 heated to 80°C by the solar heat collector 6 is introduced into the heat exchanger 6a to heat and dehydrogenate the alloy hydride 1 in the heat storage system, and at the same time Hydrogen gas pressure moves from P ₁ to P ₂ in Figure 2. Then, the valve 7 between the heat storage system 2 and the storage system 3 is opened, and hydrogen under the pressure of P ₂ is introduced into the storage system 3. In this case, since an alloy hydride with a plateau pressure bay at room temperature of P ₃ and a relationship of P ₁ < P ₃ < P ₂ (see Figures 1 and 2) is used as a storage system, (P ₂ − P ₃ ) Hydrogen corresponding to the hydrogen gas pressure moves from the alloy hydride in the heat storage system to the alloy in the storage system, and heat is stored. Next, when you want to use heat, when you open the valve 7 at room temperature, hydrogen corresponding to the hydrogen gas pressure of (P ₃ - P ₁ ) moves to the heat storage system 2, where the alloy in the heat storage system and hydrogen interact. The heat generated by the reaction is utilized by the heat exchanger 8. Specifically, the plateau pressure at 25°C of the alloy hydride in the storage system is higher than the plateau pressure at 25°C of the alloy hydride in the heat storage system.
It is also lower than the plateau pressure of the alloy hydride in the heat storage system at 80°C, and therefore the condition of P ₁ < P ₃ < P ₂ is satisfied in this hydrogen cycle, so the pressure difference is the driving force for hydrogen transfer. It is extremely easy to cycle. Of course P ₁ <P ₃ <
Conditions other than P ₂ require pressurization from other power sources, such as a hydrogen compression pump, and preheating of the alloy, making it difficult to cycle. Assuming a heat storage amount of 10,000 Kcal, the alloy hydride _in the heat storage system is CaNi ₅ H ₆ , and the alloy hydride in the storage system _{is Ca 0.9 Mm 0.1 Ni 5 H 6 or} Ca _0.8 Mm ₀ .
₂ Ni ₅ H ₆ , the combination of required amounts of each alloy is CaNi ₅ 145Kg _~ 195Kg and Ca _0.9 Mm _{0.1 Ni 5 140Kg}
~190Kg and CaNi ₅ 145Kg ~ _195Kg and _{Ca0.8 Mm0} .
₂ Ni ₅ 145Kg to 15Kg is preferred. Next, this invention will be explained with examples, but this invention is not limited to this invention. Example: CaNi ₅ alloy 1 is added to the heat storage system 2 in Figure 1, that is, the heat storage tank.
The storage system 3, that is, the storage tank, is filled with Ca ₀ .
A solar heat storage system was assembled by filling with ₉ Mm _0.1 Ni _{5 alloy} 4. Assuming a solar house (heat source: solar heat), 510 kg of CaNi ₅ alloy for the heat storage system, which can store about 30,000 Kcal, and Ca ₀ for the storage system.
500 kg of ₉ Mm _0.1 Ni ₅ alloy was prepared (respective alloy hydrides were prepared as CaNi _{5 H 6 and Ca 0.9 Mm 0.1} Ni ₅ H ₆
). In addition, the size of the tanks for the heat storage system and the storage system is such that the filling rate of the alloy is 50%, and the heat storage system is
2.9 m ² (2.9 ^L × 1 ^W × 1 ^H m), storage system is 2.8 m ² (2.8 ^L
× 1 ^W × 1 ^H m), and 3 mm thick stainless steel SUS 316 was used in consideration of material deterioration due to the use of hydrogen. In the above system, first, the heat exchange medium 5, specifically water, heated to about 80°C by the heat collector 6 is sent to the heat exchanger 6a in the heat storage system 2, and the alloy hydride in the heat storage system is 1 was dehydrogenated to generate hydrogen at a pressure of 3.5 kg/cm ² , valve 7 was opened to introduce the hydrogen into storage system 3, and alloy 4 in the storage system at room temperature was hydrogenated to store heat. Next, at room temperature, the valve 7 is opened and hydrogen in the storage system is introduced into the heat storage system to hydrogenate the alloy 1 in the heat storage system to generate heat, and the heat exchange medium 10 heated by the heat, specifically water, is transferred to the heat exchanger for heat radiation. Vessel 8
It was used for heating, cooling, and hot water. This heat storage device showed excellent thermal efficiency in heat utilization and heat storage tests. In addition, in the above embodiment, two heat exchange media 5,
Although 10 closed cycles are used to collect and radiate heat, if nighttime electricity, waste heat, or the like is used as a heat source, both functions can be performed using only one heat exchange medium closed cycle.

[Brief explanation of the drawing]

FIG. 1 is a functional explanatory diagram showing an example of a heat storage device used with the heat storage material of the present invention, FIG. 2 is a hydrogenation characteristic diagram of the heat storage system, and FIG. 3 is a hydrogenation characteristic diagram of the storage system. 1... Alloy hydride for heat storage system or its alloy, 2... Heat storage system, 3... Storage system, 4... Alloy hydride for storage system or alloy thereof, 5... Heat exchange medium, 6... Heat collection vessel, 6a... heat exchanger, 7...
Valve, 8... Heat exchanger, 9... Pump for transporting heat exchange medium, 10... Heat exchange medium.

Claims (1)

[Claims] 1 In heat storage materials that utilize thermal energy such as solar heat, CaNi ₅ alloy hydride or its alloy is used as the heat storage system, and CaxMm ₁ - as one storage system.
A heat storage material characterized by using a combination of xNi ₅ alloy hydride (in the formula, Mm is Mitsushimetal and x means a numerical value from 0.8 to 0.9).