JPH05226007A - Power generating method and generating element used therefor - Google Patents

Abstract

PURPOSE:To eliminate needs for a pump for circulating a medium thereby remarkably simplifying the shape of a device by providing storage chambers for a working solvent while having a solid electrolyte containing electrode membranes on both sides and placing them at a high temperature side or at a low temperature side reciprocally, followed by moving the solvent. CONSTITUTION:Solid electrolyte 2 containing electrode membranes 3 and 4 respectively at both end surfaces are intervened in a vessel 1 which constitutes a generating element, and storage chambers 5 and 6 for a working solvent are formed respectively at both ends of the vessel 1. First, the storage chamber 5, in which the working solvent is filled, is placed at the high temperature side while the storage chamber 6 at the low temperature side, and subsequently generation is performed while the solvent in the storage chamber 5 is transferred to the storage chamber 6 passing through the electrolyte 2. Next, the storage chamber 6 is placed at the high temperature side while the storage chamber 5 at the low temperature side, generation is performed while the solvent in the storage chamber 6 is transferred to the storage chamber 5 passing through the electrolyte 2. Accordingly, no pump is used for moving the solvent and DC power can be provided to an external circuit provided between the electrode membranes 3 and 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a power generation method for directly converting thermal energy into electric energy and a power generation element used therefor.

[0002]

2. Description of the Related Art The power generation system targeted by the present invention is called an alkali metal thermoelectric system or a sodium heat engine, and the power generation principle was proposed by JT Cummer et al. In 1969 (US Pat. No. 3,458,356).

This power generation system is 1. 1. Large output per electrode area of power generator 2. Large output per unit weight 3. 3. High energy conversion efficiency 4. The power generation scale can be freely selected. 5. Can be used with any heat source. It has a lot of advantages such as no operating part, no vibration and noise, and high reliability because it directly generates electricity.
It is attracting attention as a power generation method with high potential.

There have been several reports of power generators utilizing this power generation principle. FIG. 3 shows a conventional power generator, in which the solid electrolyte 2 such as β-alumina or β ″ -alumina, and the positive electrode film 1 on the + side of the solid electrolyte.
0, a high temperature side heat source 8 is provided so as to face the positive electrode film 10, and a low temperature condenser 9 and a circulation pump 11 are provided below the high temperature side heat source 8 and the positive electrode film 10 and the solid electrolyte on the opposite side. An external circuit 7 connecting the two is provided.

The working medium such as sodium is brought into a liquid phase state by the low temperature side condenser 9, and then is supplied as it is to the solid electrolyte 2 on the side opposite to the positive electrode film 10 in the liquid phase state.

The working medium such as sodium supplied to the left side of the solid electrolyte 2 (on the side opposite to the positive electrode film 10) releases electrons at the electrolyte interface and is ionized, and moves to the positive electrode film 10 to move to the positive electrode film 10. Then, the electrons are received and reduced, and at the same time, they are evaporated by the heat from the high temperature side heat source 8.

Further, the working medium in the vapor phase moves to the low temperature side condenser 9, is condensed there, and the working medium in the liquid phase is opposite to the positive electrode film 2 in the initial state by the circulation pump 11. Is supplied to the solid electrolyte 2 on the side. By configuring such a cycle, it is possible to generate DC power in the external circuit 7.

[0008]

One of the major problems of the alkali metal thermoelectric conversion system is the characteristics of the pump. In the conventional device as described above, the pump 11 is usually an electromagnetic pump.

The electromagnetic pump has features such as no moving parts and less problems of sealing, but its efficiency is low, and it is suitable for large flow rate and low pressure difference. Therefore, it has a small flow rate like alkali metal thermoelectric conversion. The performance does not match the specifications that require a high pressure difference.

That is, in alkali metal thermoelectric conversion, at least 1 to
A pressure difference of 2 atm is required, which increases the flow path length and the coil section in the pump, and makes the efficiency of the pump remarkably low at a small flow rate. Also, if a mechanical pump is used instead of the electromagnetic pump, there is a problem with the seal.

The output power of the alkali metal thermoelectric conversion is characterized by low voltage and high current, and it is necessary to connect power generating elements in series in practical use. At that time, a conventional pump is used. Then, it is necessary to electrically insulate the flow path (the supply path from the pump to the solid electrolyte) of the working medium of each power generating element itself. For that purpose, it is necessary to insulate both the pipe and the working medium between them, but since the pipe is usually made of metal, it is necessary to provide an insulating material such as ceramic in the middle of the flow path for insulation. This gives rise to sealing problems at the connection.

Furthermore, in the above-mentioned power generation system, since an electrically conductive medium such as sodium is used as the working medium, it is necessary to insulate the working medium in the pipe, and as a method for insulating the working medium in the liquid phase, Although there is a method of inserting a gas phase portion between the working medium and this method, this method structurally complicates the device, and the liquid phase due to condensation adheres to the insulated portion as a gas phase to break the insulation. There are difficulties such as high possibility.

It is also possible to connect the power generating elements in series by independently providing a pump for each power generating element, but in this case, there is a problem in the characteristics of the pump provided in each power generating element.

That is, the power generation output of one power generation element is restricted by the size of the solid electrolyte, and even if the power generation output is assumed to be 1000 W, the movement amount of the working medium is about 30 cc per minute, Since it does not match the large flow rate and low pressure difference characteristics of the conventional electromagnetic pump, and the efficiency of the pump is extremely low, it is necessary to miniaturize the pump to suit each power generating element. However, this miniaturization is an extremely difficult problem.

[0015]

In order to solve the above problems, a first electrode is provided on one surface in a container forming a power generating element.
A solid electrolyte having a second electrode on the other surface is interposed, and the inside of the container is divided into a first storage chamber and a second storage chamber for the working medium. First, the first storage chamber loaded with the working medium is placed on the high temperature side. The other storage chamber on the low temperature side, power is generated while the working medium in the first storage chamber moves to the second storage chamber through the electrode and the solid electrolyte, and then the second storage chamber. The chamber is positioned on the high temperature side, the first storage chamber is positioned on the low temperature side, and power is generated while the working medium in the second storage chamber is moved to the first storage chamber through the electrode and the solid electrolyte. The proposed power generation method and the power generation element used for this method are proposed.

[0016]

In the present invention, the working medium loaded in the first chamber is heated by the heat source on the high temperature side, passes through the first electrode, and is supplied into the solid electrolyte. At this time, electrons are emitted at the interface of the electrolyte and ionized, further move to the second electrode, where they are received and reduced, and the working medium that has passed through the second electrode reaches the second storage chamber, where It is cooled on the low temperature side.

Next, by positioning the second storage chamber on the high temperature side and the first storage chamber on the low temperature side, the working medium in the second storage chamber is heated on the high temperature side and passes through the second electrode. Are supplied into the solid electrolyte, at which time electrons are emitted at the interface of the electrolyte to be ionized, further move to the first electrode, where they are received and reduced, and the working medium passing through the first electrode is It reaches the first chamber, where it is cooled on the low temperature side.

As described above, according to the present invention, DC power can be generated in the external circuit provided between the first and second electrodes without using a pump for moving the working medium.

As a method of moving the positions of the first storage chamber and the second storage chamber from the high temperature side to the low temperature side, the positions of the high temperature side and the low temperature side are fixed, and the first storage chamber and the second storage chamber are fixed. The positions may be interchanged, and conversely, the first storage chamber and the second storage chamber may be replaced.
The position of the storage chamber may be fixed, and the positions of the high temperature side and the low temperature side may be switched.

Therefore, according to the present invention, the device can be simplified. Specifically, not only the pump can be omitted, but also the piping of the working medium connected to the pump, the control system of the pump, and the power source can be omitted, and further simplification can improve the reliability of the device.

Further, in the present invention, since the working medium can be moved without using a pump, the airtightness of the power generating element can be enhanced.

Further, the power generating element according to the present invention can be housed in a small and hermetically sealed container. Therefore, by insulating the container including the power generating element from the surroundings, the series connection can be easily and surely performed. In practice, this is extremely effective when the power generating elements are connected in series.

The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention, in which 1 is a vertically long container constituting a power generating element, and a solid electrolyte 2 such as β-alumina or β ″ -alumina is provided in the center of the container 1. A first electrode film 3 and a second electrode film 4 are provided on both upper and lower surfaces of the solid electrolyte 2, and further, a first storage chamber 5 is provided at the upper and lower parts of the container 1 separated by the solid electrolyte 2.
The second storage chamber 6 is formed.

An external circuit 7 is connected to the first electrode film 3 and the second electrode film 4, and the high temperature side heat source 8 and the outer circumference of the second storage chamber 6 are connected to the outer circumference of the first storage chamber 5. A low temperature side capacitor 9 is provided.

The shape of both surfaces of the solid electrolyte 2 is flat plate in this embodiment, but other shapes such as cylindrical shape and corrugated plate shape can be freely selected.

In this embodiment, of the above-mentioned storage chambers, the working medium is loaded in the first storage chamber 5. A medium having a high solid electrolyte ionic conductivity is selected as the working medium. For example, when a solid electrolyte such as β-alumina or β ″ -alumina is used, an alkali metal such as sodium, potassium, cesium or mercury can be used, and other solid electrolytes should be used. Thus, the use of other working media is also possible.

In the above structure, the working medium contained in the first containing chamber 5 is heated by the high temperature side heat source 8, passes through the first electrode membrane 3, the solid electrolyte 2 and the second electrode membrane 4 and is moved downward. It moves and is stored in the second storage chamber 6, where it is cooled by the low temperature side condenser 9 and is stored in the second storage chamber 6.

Then, the working medium releases electrons at the interface of the solid electrolyte 2 to be ionized, and further receives and is reduced by the second electrode film 4, whereby DC power is generated in the external circuit 7.

When the amount of the working medium in the first storage chamber 5 decreases due to the movement of the working medium and the amount of the working medium in the second storage chamber 6 increases, the vertical position of the container 1 is reversed and the second position is set.
The accommodation chamber 6 is located at the high temperature side heat source 8, and the first accommodation chamber 5 is located at the low temperature side condenser 9.

As a result, the working medium having a low temperature accumulated in the second storage chamber 6 receives heat from the high temperature side heat source 8 and rises in temperature, and is sent to the solid electrolyte 2, and the solid electrolyte 2 is the same as above.
Electrons are emitted and ionized at the interface of, and the electrons are received by the first electrode film 3 and reduced, whereby DC power is generated in the external circuit 7.

The working medium that has passed through the first electrode film 3 reaches the first accommodating chamber 5, where it is cooled by the condenser 9 on the cooling side. In this way, electricity can be generated without a pump.

In the present invention, the temperature of the working medium is rapidly raised or lowered, but in this case, when the temperature of the solid electrolyte portion is rapidly changed, the solid electrolyte 2 is stressed due to the temperature difference. Crack growth is expected.

Therefore, as shown in FIG. 1, the solid electrolyte 2
It is necessary to minimize the temperature change by always arranging the part of (1) toward the high temperature side heat source 8.

FIG. 2 shows another embodiment. In this case, an inverted U-shaped container is used as the container 1 which constitutes the power generating element, and the center of the container is the same as that of FIG. The solid electrolyte 2 having the first electrode film 3 and the second electrode film 4 is interposed, the first storage chamber 5 and the second storage chamber 6 for the working medium are provided at both ends thereof, and the high temperature side is provided on the outer periphery of the first storage chamber 5. Heat source 8 and second
A low temperature side condenser 9 is provided on the outer periphery of the accommodation chamber 6.

Then, in this embodiment, the working medium loaded in the first storage chamber 5 is heated by the high temperature side heat source 8 to be in a gas phase state, supplied to the solid electrolyte 2 and generated in the same manner as above to generate the second storage. It is housed in the chamber 6, where it is cooled and condensed by the low-temperature condenser 9 (FIG. 2A).

Next, when the low temperature side condenser 9 is placed on the outer circumference of the first storage chamber 5 and the high temperature side heat source 8 is placed on the outer circumference of the second storage chamber 6 while keeping the container 1 as it is, the heat is accumulated in the second storage chamber 6. The working medium is supplied to the solid electrolyte 2 in the gas phase, and power generation is performed in the same manner as above (FIG. 2B).

[0037]

In summary, according to the present invention, the working medium circulating pump, which has been necessary in the past, is not required, and the shape of the device can be greatly simplified.

Further, problems such as low efficiency and sealing in the conventional pump use can be solved, and the method of the present invention is also advantageous in terms of energy balance.

Further, it is a great effect that the present invention facilitates series connection of the power generating elements.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

2 is a schematic diagram showing another embodiment of the present invention, FIG.
FIG. 2 is a diagram showing a mode in which the working medium is supplied from the first storage chamber to the second storage chamber, and FIG. 2B is a diagram showing a mode in which the working medium is supplied from the second storage chamber to the first storage chamber.

FIG. 3 is a schematic diagram of a conventional power generation method.

[Explanation of symbols]

 1 Container 2 Solid Electrolyte 3 First Electrode Membrane 4 Second Electrode Membrane 5 First Containment Chamber 6 Second Containment Chamber 7 External Circuit 8 High Temperature Side Heat Source 9 Low Temperature Side Capacitor

Claims (2)

[Claims] 1. A solid electrolyte having a first electrode on one surface and a second electrode on the other surface is interposed in a container constituting a power generating element, and a second storage chamber for a working medium and a second storage chamber are provided in the container. First, the first storage chamber in which the working medium is loaded is located on the high temperature side, the other storage chamber is located on the low temperature side, and the working medium in the first storage chamber is divided into the electrode and the solid electrolyte. Electric power is generated while passing through and moving to the second storage chamber, then the second storage chamber is positioned on the high temperature side, the first storage chamber is positioned on the low temperature side, and the working medium of the second storage chamber is set to the electrode. A power generation method is characterized in that power is generated while passing through the solid electrolyte and moving to the first storage chamber. 2. A solid electrolyte having a first electrode on one surface and a second electrode on the other surface is interposed in the container to divide the container into a first storage chamber and a second storage chamber for a working medium. And the first,
An electric power generation element characterized in that an external circuit is connected between the second electrodes.