JPS5819956B2 - Cooling device using metal hydride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention focuses on the amount of heat absorbed by metal hydride compounds, and relates to a cooling system that utilizes this heat absorption effect. This project proposes a cooling device.

In other words, when two types of metal hydride compounds with different hydrogen equilibrium pressures are housed in two sets of metal containers, how many metal hydride compounds (heating metal containers) are heated by solar heat, waste heat, etc. At the same time, the electromagnetic valve is opened to cause the metal hydride compound CB) on the other side to absorb N2 gas.

When the release → storage of N2 gas is completed, the heating of the metal hydride compound is stopped, and the metal hydride compound is allowed to absorb N2 gas by natural cooling or forced cooling, and the pressure inside the metal container is reduced to release metal hydrogen. N2 gas is released from compound (B).

Since the reaction in which N2 gas is released from the metal hydride due to reduced pressure is endothermic, the amount of heat absorbed at this time is utilized for cooling.

In other words, this is a new cooling device that alternately heats and cools one metal hydride compound, releases N2 gas under reduced pressure in the other metal hydride (CB), and uses its endothermic action for cooling function.

It has long been known that many metals absorb hydrogen and form hydrogen compounds.

In this case, more hydrogen is absorbed per unit weight of the metal, and the hydrogen is reversibly released at the operating temperature.

It is also known that the process of releasing hydrogen from pure metal hydrides is an endothermic process.

Here, M is a metal, Ql - amount of heat generated If this metal hydride compound is shown in general chemical formula, AB5I (
X is a lanthanide (La) known as a rare earth, B is nickel (Ni) or cobalt (co), H is hydrogen, and yu is a variable that varies over a wide range.

As an example, the characteristics of L a N i 5 HX will be explained.

Figure 1 shows L a N i 5 with humidity as a parameter.
- Show the relationship between the hydrogen content of melon and the equilibrium pressure.

At a given temperature and pressure (equilibrium pressure), LaN
15-HX are balanced with each other.

This equilibrium structure varies over a wide range of atmospheric pressures, as shown in Figure 1.

The equilibrium pressure has a virtually constant value over a wide range of the X axis.

When a hydrogen pressure slightly higher than the equilibrium pressure is applied to such a LaN15-HX metal hydride compound, hydrogen is occluded until a hydrogen-rich hydrogen compound is formed.

Also, when hydrogen can be released (by lowering the temperature or lowering the pressure), the pressure drops rapidly to a plateau, and at a constant pressure, hydrogen is depleted.

When hydrogen is released, the hydrogen-rich metal hydride turns into a hydrogen-free metal compound.

If a polyhydric metal hydride is completely changed to a hydrogen-free metal hydride, the pressure will be below the plateau voltage.

The value of this flat voltage depends on the temperature; at high temperatures, the hydrogen pressure is higher than at low temperatures.

Figure 2 shows the relationship between humidity and pressure.

As described above, metal hydride compounds undergo a hydrogen release process by increasing the temperature or lowering the equilibrium pressure from a certain equilibrium state.

In the opposite case, it becomes a hydrogen absorption process.

As mentioned above, this hydrogen release process is an endothermic reaction.

The amount of heat absorbed varies depending on the type of metal hydride compound,
For example, LaN15-HXs 5mCo5-HX is 7.2
Kcal.

/mol N2 s F e T 1-HX is 5.
There is an endothermic amount of 5 Km/mo I N2.

Two types of optimal materials are selected from the temperature-equilibrium pressure curve of the metal hydride compound as shown in FIG. 2 and used in the cooling device.

For example, combine A material and B material.

Material A is used for heating, and material B is used for cooling.

T1 is the temperature at which the metal hydride (F) can be cooled when releasing hydrogen.

That is, the minimum temperature of the metal hydride compound required for a cooling capacity of 2500 Kc111/hr needs to be maintained at about 7 to 8°C.

T2 is the hydrogen storage temperature of the metal hydride.

T3 indicates the heating temperature during pressurization of the metal hydride prison.

At this time, the equilibrium pressure of metal hydride compound ■, (B) is P1=1
It shows that 0 atm4P2-=2.3 atm.

Depending on the temperature of the metal hydride on one side in the metal container,
The pressure within the metal container can be adjusted to suit the hydrogen release and storage process.

In the present invention, L a N i 5-HX s MmC0
5-HX (Mm: mesh metal), SmC
05-HX.

In addition to VNb-H, F e T 1-HX # VH
X tNbHz, PdHX, Mg2Cu-HX
eMg2 N I HX t Mg Hz , L
a The metal hydride compound, which is a combination of two types of metal hydride compounds with different hydrogen equilibrium pressures such as alkali metals such as C05HX, alkaline earth metals, rare earth elements such as lanthanides, actinide element group, and transition metals, cools the air conditioner. Available as a source.

The new cooling device of the present invention is shown in FIGS. 3, 4, and 5.

Further, FIG. 6 shows the layout of the cooling device, and FIG. 7 shows the cooling capacity characteristics.

Examples of the present invention will be shown below.

The cooling device shown in FIG. 3 consists of the following components.

A heating metal container 1 containing a metal hydride compound (A) 2 and a cooling metal container 3 containing a metal hydride compound (B) 4 are connected via an electromagnetic pulp 7 with an N2 gas pipe 11.

Further, a cooling heat exchanger 5 and a solar heater (heat collector) 13 are attached to the metal container 1.

The other metal container 3 is equipped with an air-cooled heat exchanger 14 that performs air cooling using a cooling heat exchanger 6 and a cooling fan 15.

Three-way automatic electromagnetic valves 8 and 9 and heat exchangers 5 and 6 are connected by liquid piping in order to absorb the calorific value of the metal hydride compound and store it in the hot water storage device 10.

The metal containers 1 and 3 are of a heat exchanger type and have a structure that allows them to efficiently perform heat absorption and heat radiation functions.

First, VNbHX was used as the metal hydride compound (A) 2, and LaNi5-HX was used as the metal hydride compound (B) 4.
sF”eT i -HX, 5mCo5-HX was used.

Samples of metal hydride compounds were produced according to known production methods and used for experiments.

The amount of metal hydride compound was calculated from the hydrogen storage capacity and endothermic amount.

As an example, the case of LaN15-)L used for cooling will be calculated.

The standard cooling capacity of a general room air conditioner is approximately 2500Kc.
al/hr.

The heat absorption amount of LaNx5 HX is ΔQ = 7.2 Km/
Since m o l N2, this is 3600Km/K
It corresponds to gH,2.

The hydrogen gas content of L a N 15 HX is 1.5w
Since it is t, the amount of heat absorbed per 1 kg of L a N i 5-HX is Q=I El/1 kgxl/2X7.2Km
=54Kcal/kg.

Since the cooling capacity is currently 2500 KcaI/hr, the required amount of L a N i5 HX is 46 kg/hr.
It becomes hr.

The amount of metal hydride compound is determined by the time of one operation.

This time, 46 kg x 3 hr = 138 and 9 were used as the amount required to cool the air conditioner for 3 hours/day during the day.

As the metal hydride on the side heated by cold solar heat, VNb-trium was used.

VNb-H, absorbs 2.1 wt% hydrogen.

Therefore, LaNt5 HX was used in an amount greater than the required amount so as to sufficiently exhibit a cooling effect.

In other words, the amount of N2 gas required for cooling at 2500 Kaii/hr corresponds to approximately 0.94 kg.

Therefore, the required amount of VNb-take per hour is approximately 45
kg (940/2.1 x 100 characters 45 kg).

Approximately 140 kg was used as the amount needed for three hours of cooling.

The internal volume of the metal hydride compound is approximately 70%, the air volume of the cooling fan is approximately 5m3/mi or less, and the outlet temperature is approximately 15%.
I was able to get cold air at ℃.

(However, when the inlet temperature was 27° C.) Cooling was performed for 3 hours.

Also, in the case of F e T 1-HX, the cooling capacity is 2500Kc.
Required 55 kg for al/hr and used 165 kg for 3 hour cooling.

In this case as well, as in the case of LaNi5-trium, cold air with an outlet temperature of about 15° C. could be obtained with an air flow rate of about 5 m 3 /i or less from the cooling fan.

(However, when the inlet temperature is 27°C) Next, in the example shown in Figure 4, the metal hydride used is the same as that used in the example of Figure 3; The difference is that the model shown in Figure 3 directly collects solar heat for heating, whereas the model shown in Figure 4 uses a circulation pump 16.
The metal hydride compound (A) 2 is heated indirectly using the medium circulation pipe 17.

The circulating medium was heated by solar heat, and the metal hydride compound (A) 2 was heated with the heated medium.

Water was used as the medium.

During cooling, the circulation of the medium is stopped and the metal hydride compound (A
) By lowering the humidity of 2 and lowering the pressure inside the metal container 3, a cooling effect was performed.

This is based on exactly the same principle as the embodiment shown in FIG.

Next, in the example shown in FIG. 5, the metal hydride used was the same as that used in the example shown in FIG.
The difference from the embodiment shown in FIG. 3 is that the embodiment shown in FIG. 3 directly collects solar heat for heating, whereas the embodiment shown in FIG.
7 is used to indirectly heat the metal hydride compound (A) 2.

Then, as a heat source, waste heat is used to heat the circulating medium, and the heated medium is used to generate metal hydride compound (A) 2
was heated.

During cooling, the circulation of the medium is stopped and the metal hydride (
A) A cooling effect was performed by lowering the temperature of 2 and lowering the pressure inside the metal container 3.

This is also based on exactly the same principle as the embodiment shown in FIG.

In the embodiments shown in FIGS. 3, 4, and 5, the N2 gas occlusion reaction is an exothermic reaction, so water cooling was used except for natural cooling.

Further, the embodiment shown in FIG. 3 was carried out using a layout similar to the solar direct type cooling device shown in FIG. 6a.

A solar heater 13 was provided above the heating metal container 1 containing the metal hydride compound (A) 2, and was placed outdoors so that the metal hydride compound (A) 2 was directly heated by solar heat.

On the other hand, a cooling metal container 3 containing a metal hydride compound (B) 4 was installed indoors, and a cooling device was arranged so that the cooling fan 15 supplied cold air into the room by connecting it through an electromagnetic valve 7. .

Further, the embodiment shown in FIG. 4 was carried out using a layout diagram similar to that of the solar indirect type cooling device shown in FIG. 6.

A heating metal container 1 containing a metal hydride compound (A) 2 is provided under the floor, a solar heater 13 which also serves as a roof is heated by solar heat, a medium circulated by a circulation pump 16 is heated by this heat source, , which has a structure in which the metal hydride compound (A) 2 is heated.

On the other hand, a cooling metal container 3 containing a metal hydride compound a3)4 was provided indoors, connected via an electromagnetic valve 7, and a cooling device was arranged so that a cooling fan 15 supplied cold air into the room.

Next, the operation of this cooling system will be explained.

The air inside the metal container was first replaced with N2 gas and then replaced with H2 gas to make it completely airtight.

Next, when the heater (heat collector) is heated with solar heat and the metal hydride compound (A) 2 in the metal container 1 is heated, the pressure in the metal container 1 increases and the metal hydride compound (A) 2 is heated up. begins to be released, and at the same time, the inside of the metal container 3 is similarly pressurized, so the metal hydride compound (B) 4 begins to absorb hydrogen.

This process corresponds to process (■) in FIG.

In other words, the process is d-+a-+b for the metal hydride compound, and d'→a'→b/ for the metal hydride compound CB.

Next, a shielding plate is installed to block the irradiation of solar heat to the collector, the humidity of the collector is lowered, the humidity of the metal hydride compound (■) is lowered to about 50°C, and the pressure inside the metal container 1 is reduced. By doing so, hydrogen gas is released from the metal hydride compound (B) and is stored in the other metal hydride compound (A).

At this time, the metal hydride (B) is lowered to about 7-8°C.

On the other hand, since the metal hydride prison generates heat, in order for the reaction to proceed smoothly, when the humidity rises above about 50°C, water cooling is performed to about 50°C.

This process corresponds to process (■) in FIG.

That is, for metal hydride CB), b'→C'→d'
The process is an endothermic reaction and the temperature drops to 7-8℃, so
This amount of heat absorbed can be used for cooling.

When the cooling function is no longer available, the metal hydride compound (CB) is heated again using solar heat to store hydrogen in the metal hydride compound (CB).

The electromagnetic valve 7 is closed to prevent hydrogen gas from flowing backwards, and the electromagnetic valve is opened when necessary to release H2 gas and perform cooling.

Note that the electromagnetic valve 7 is not limited to this, and may be another automatic valve.

At night, solar heat cannot be used, so the inside of the metal container 1 cannot be pressurized.

However, if the metal hydride compound CB) absorbs hydrogen during the day using solar heat, air conditioning can be achieved even at night.

Also, when waste heat can be used, air conditioning can be done at any time, day or night, as long as there is waste heat as a heat source.

Of course, air conditioning can also be achieved by using electric heaters, gas, etc. as a heat source.

Air conditioning cannot be performed while hydrogen gas is stored in the metal hydride compound (B).

Therefore, one set of this cooling device cannot be used continuously.

Hydrogen must be absorbed and stored for the required cooling time.

When cooling is complete, the metal hydride on the cooling side (
B) can store hydrogen.

The actual internal temperature and pressure of the cooling device are as follows.

Pl = 10 atm P2 = 2.3 atm T2
= Approximately 50°CT to 7-8°CT3-95°C Maximum temperature is 95°C1 Pressure is less than 10 atm, which allows cooling at very low temperatures and pressures.

The key points are the solar heating process (a-+b) and the cooling process (c/→d').

Furthermore, it is difficult to quickly lower the temperature of the metal hydride (5) in terms of heat capacity.

Therefore, it is ideal to release hydrogen gas from the metal hydride compound B at a relatively high cooling temperature at this time.

Taking this into consideration, it is appropriate for the humidity T2 to be approximately 50°C or higher.

Water cooling is still more effective than air cooling.

Further, as shown in FIG. 7, the cooling capacity of this cooling device is determined by the amount of built-in metal hydride compound, and the larger the amount, the greater the cooling capacity.

Furthermore, various types of cooling devices can be made by combining various metal hydride compounds.

Mg-based metal hydride compounds allow for relatively lightweight cooling devices, but the maximum pressure is too high.

Metal hydrides such as MmNt5 HX can be used at low temperatures (
Since the H2 dissociation pressure at -20°C) is several atm, which is high compared to other products, cooling is possible down to a very low temperature range.

Note that the two types of metal hydrides with different hydrogen equilibrium pressures may be a mixture, and it is sufficient that the containers contain materials with different hydrogen equilibrium pressures.

As described above, the present invention uses two metal containers each containing two types of metal compounds with different hydrogen equilibrium pressures, so when hydrogen gas is stored and released between the two containers, a compression pump or a heating The load on forcing means for hydrogen gas transfer, such as sources, is reduced.

In other words, in the case of metal hydride compounds with the same hydrogen equilibrium pressure, even if the pipes connecting both containers are connected during initial operation, hydrogen will not move, and a pressure difference will be created with a compression pump, or waste heat will be transferred. It is necessary to create a pressure difference using , which requires time.

However, when two types of metals with different hydrogen equilibrium pressures are used as in the present invention, the movement of hydrogen gas begins simply by communicating the two containers at startup, and no power is required at startup, and there is no waiting time at startup. will also decrease.

[Brief explanation of drawings]

Figure 1 is a diagram of the relationship between the hydrogen component and equilibrium pressure of L a N i5 HX, and Figure 2 is the temperature (1/T) of the metal hydride compound.
Figure 3, Figure 4, Figure 5, and Figure 6 a and b are diagrams showing the configuration of a cooling device showing an embodiment of the present invention, and Figure 7 is a diagram showing the relationship between pressure and pressure (log H2). It is a characteristic diagram. 1.3...Metal container, 2...Metal hydride compound (A)
4...Metal hydride compound CB), 7...Solenoid valve (
automatic valve), 13...heater.

Claims (1)

[Claims] 1. Two metal containers each containing two types of metal hydride compounds having different hydrogen equilibrium pressures, a heat exchanger provided in the metal containers, and means for connecting the metal containers via an automatic valve. A cooling device using a metal hydride compound that releases hydrogen gas from the metal container using solar heat or various types of waste heat, and exhibits a cooling function on the side of the metal hydride compound that has a high hydrogen equilibrium pressure.