KR20090124176A - Renewable energy-regenerative fuel cells hybrid system for residence - Google Patents

Abstract

PURPOSE: A renewable energy-regenerative fuel cell hybrid system for residence is provided to facilitate energy storage, to increase fuel efficiency, and to reduce costs using a complex technology combined with a alkali type regenerative fuel cell and a renewable energy system. CONSTITUTION: A renewable energy-regenerative fuel cell hybrid system(100) for residence comprises a renewable energy part(110) which generates electrical energy using a solar battery or aerogenerator; a power supply part(130) which converts some of electrical energy into commercial power in the energy part and supplies the energy to the residence; and an alkali type renewable fuel cell part(150).

Description

Renewable energy-regenerative fuel cells hybrid system for residence

The present invention relates to a residential renewable energy-renewable fuel cell complex system, and more particularly to a residential renewable energy-renewable fuel cell complex system that can be used more efficiently by using a renewable fuel cell and a renewable energy system. will be.

It is a time when new technologies such as IT and bio are deployed on a global scale, but even in such a situation, the energy industry is a very important infrastructure industry and continuous research and development is being made.

Recently, as awareness of the necessity of preventing global warming has increased, expectations for the development of so-called new energy are rising. In addition to the environment, new energy can be produced in a decentralized manner in which power demand is close, and thus has advantages in terms of transmission loss and guarantee of power supply.

In addition, the development of new energy can also expect the secondary effect of creating a new surrounding industry. The response to new energy began in earnest after the oil crisis of about 30 years ago, and now renewable energy such as photovoltaic power generation, The development of energy such as recycled energy such as waste power generation, high-efficiency energy such as fuel cells, and new field energy such as clean energy vehicles has reached practical stages.

Among them, fuel cells are one of the industry's most notable energy sources. Hydrogen produced by reacting water vapor with natural gas, methanol, etc., and electricity is produced by electrochemical reaction of oxygen in the atmosphere. Not only does it emit no harmful components at all, it is highly efficient in the low power area, and furthermore, the power generation is stable without being influenced by the climate.

Among these, regenerative fuel cells (RFCs) are electrolysis processes that produce hydrogen and oxygen from water and fuel cells that generate electricity by receiving hydrogen and oxygen.

About 80% of the residential fuel cell devices currently researched and marketed are based on polymer electrolyte fuel cells (PEFCs), and most of them use solid oxide fuel cells (SOFCs). .

However, when using the renewable fuel cell alone, it is inconvenient to establish an infrastructure according to the use of hydrogen because fuels such as hydrogen and oxygen must be supplied separately, and expensive catalysts such as platinum and Nafion ( There was a problem that the Nafion series membrane and the like are not suitable for residential use where cost and durability are a priority.

In addition, in recent years, efforts have been made to develop an efficient energy system by combining the renewable fuel cell with other energy technologies. For example, development of a composite technology of a renewable fuel cell and a solar cell has been made.

The renewable fuel cell and solar cell composite technology is currently being researched and developed by NASA with a focus on aerospace, and this composite technology also uses a polymer electrolyte fuel cell as a renewable fuel cell. Because of its size, it can be usefully used for aerospace, but it has been a problem that it is not suitable for commercial use in residential use.

Accordingly, there is a demand for the development of an efficient composite fuel cell system that improves the above problems as a residential energy system.

The present invention was created in order to meet the necessity of the above-described technology development, and it is convenient to store energy, increase fuel efficiency, and reduce costs by using a combined technology combining an alkaline renewable fuel cell and a renewable energy system. To provide an economical residential renewable energy-renewable fuel cell complex system.

Residential renewable energy-renewable fuel cell composite system of the present invention for achieving the above object, in the residential energy system for generating electrical energy to supply the residential power, using a solar cell or a wind power generator Renewable energy generating unit; A power supply unit which converts some of the electrical energy generated by the renewable energy unit into commercial power and supplies the same to a residential power source; Hydrogen and oxygen are produced by electrolyzing water with the remaining electrical energy not supplied to the housing among the electrical energy generated by the new and renewable energy unit, and generating secondary electrical energy using the hydrogen and oxygen to generate the secondary unit. An alkali type renewable fuel cell part is provided.

That is, the renewable energy unit uses a solar cell or a wind power generator that absorbs primary energy such as solar energy or wind energy and converts it into electrical energy, and is not continuously supplied, but has limited primary energy depending on time or climate. Since there was a problem to use stably as residential power, there was a problem that the storage of energy is not easy.

Therefore, in the case of utilizing the renewable energy system and renewable fuel cell system as a residential power as in the present invention, solving the problems of the renewable energy system as described above, regardless of time and climate through the renewable fuel cell system It can supply power stably.

In addition, according to the user's selection, only a part of the electrical energy generated by the new energy generated by the new renewable energy to supply the residential power, the remaining surplus electrical energy is supplied to the alkaline renewable fuel cell unit by electrolyzing the water Hydrogen and oxygen can be obtained.

Here, the alkaline type renewable fuel cell unit, an alkaline type renewable fuel cell for generating hydrogen and oxygen by electrolysis of water to receive electrical energy or to generate the secondary electrical energy by receiving hydrogen and oxygen, and the alkali type It is preferable that an energy storage unit for compressing and storing hydrogen and oxygen generated in the renewable fuel cell with a compressor and then resupplying the alkaline renewable fuel cell according to a user's selection is provided.

When the alkaline renewable fuel cell unit further includes the energy storage unit, the generated hydrogen and oxygen are stored in a form of chemical energy that is easily compressed and stored according to the user's selection even when it is difficult to supply power by the renewable energy unit. There is an advantage that can easily supply residential power.

Further, it is preferable that the renewable energy unit generates electrical energy in the range of 0.5 to 3000 kW per unit second, and the alkaline type renewable fuel cell unit generates secondary electrical energy in the range of 0.5 to 1000 kW per unit second.

Residential renewable energy-renewable fuel cell composite system of the present invention as described above,

First, it is possible to provide an economical and practical residential complex energy system that complements the disadvantages of the renewable energy system with irregular power supply and the disadvantages of the high-cost renewable fuel cell by linking the alkaline renewable fuel cell with the renewable energy system. .

Secondly, according to the user's choice, when the amount of power consumption is large and small, preferentially, only the necessary electric energy is supplied from the renewable energy department, and the remaining electric energy is used to electrolyze water to generate hydrogen and oxygen. It is economical and efficient because there is no need to supply fuel separately with closed system used to operate renewable fuel cell.

Third, there is no limit on the size of the system, it can be used for large apartments of several MW as well as single-family house of several kW.

Fourth, the use of the alkaline type renewable fuel cell not only reduces the cost, but also uses only hydrogen and oxygen generated by the electrolysis of water during fuel supply, thereby preventing carbonation of the electrolyte potassium hydroxide since carbon dioxide is not contained.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly introduce the concept of terms in order to best explain their invention. It should be interpreted as meanings and concepts in accordance with the technical spirit of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in the present specification and the configuration shown in the drawings are only the most preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It should be understood that there may be water and variations.

Hereinafter, a residential renewable energy-renewable fuel cell complex system according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

1 is a schematic view showing the operation of the residential renewable energy-renewable fuel cell composite system according to an embodiment of the present invention, Figure 2a is a renewable energy unit in the residential renewable energy-renewable fuel cell composite system of FIG. Is a schematic diagram showing a case of supplying electric energy generated to the house preferentially and storing the remaining electric energy in the form of chemical energy of hydrogen and oxygen through the electrolysis process of the alkaline type renewable fuel cell, and FIG. Figure 2 is a schematic diagram showing a case of supplying the secondary electric energy generated in the alkaline renewable fuel cell unit to the housing in the residential renewable energy-renewable fuel cell complex system of Figure 3 is a residential renewable energy-renewable fuel cell of Figure 1 Schematic diagram showing the electrolysis process of water (a) and the secondary electrical energy generation process (b) by the fuel cell in the composite system.

Referring to FIG. 1, the residential renewable energy-renewable fuel cell complex system 100 according to an embodiment of the present invention includes a renewable energy unit 110, a power supply unit 130, and an alkaline renewable fuel cell unit ( 150).

The renewable energy unit 110 receives irregular and intermittent primary energy such as solar energy or wind energy and converts it into electrical energy.

The renewable energy unit 110 may rotate the windmill by a solar cell or wind power that absorbs sunlight and converts solar energy into electrical energy, and may use a wind power generator that converts energy generated therefrom into electrical energy. .

The solar cell converts solar energy into electrical energy, and emits photovoltaic power by photoelectric effect by irradiating light to a contact surface of a metal and a semiconductor or a pn junction of a semiconductor. That is, the solar cell module receives light to generate electrons and holes in the interior, and when the generated charges are moved to the P pole and the N pole by an electric field, a potential difference is generated between the P pole and the N pole. At this time, when a load is connected to the solar cell, a current flows, which is called a photoelectric effect.

Here, the solar cell can be roughly divided into using a silicon semiconductor as a material and a compound semiconductor as a material, and the use of a silicon semiconductor as a material is further classified into a crystalline silicon solar cell and an amorphous silicon solar cell. do.

At present, most commonly used solar cells are made of silicon semiconductors. Among these, crystalline silicon semiconductor solar cells are further divided into single crystals and polycrystals, which are widely used because of their excellent conversion efficiency and high reliability.

In addition, since silicon semiconductor solar cells are somewhat expensive, a compound solar cell of low cost but low conversion efficiency may be used. In order to compensate for the high cost of silicon solar cells, such compound solar cells are currently undergoing various studies to increase conversion efficiency, which is pointed out as a disadvantage.

Therefore, the solar cell used for the renewable energy unit 110 of the residential renewable energy-renewable fuel cell complex system 100 according to an embodiment of the present invention absorbs sunlight as primary energy according to the object of the present invention. All kinds of solar cells that generate electrical energy can be included.

In addition, the wind power generator is a generator that generates electricity by rotating the windmill with the wind, is environmentally friendly, and does not need to supply fuel such as fossil raw materials or gas, attracting attention as a future eco-friendly renewable energy system.

As described above, the renewable energy unit 110 of the present invention described only a renewable energy system using a solar cell and a wind power generator, the renewable energy unit 110 of the present invention according to the purpose of the present invention alkali type All economical renewable energy systems that can be used in conjunction with renewable fuel cells can be included.

The power supply unit 130 converts some of the electrical energy generated by the renewable energy unit 110 into commercial power and supplies it to the house, and supplies the electrical energy generated from the renewable energy unit 110 to the house. It converts direct current electric energy into alternating current electric energy or converts direct current electric energy into direct current electric energy for use as commercial power.

That is, the power supply unit 130 receives the electrical energy generated from the renewable energy unit 110 and supplies some of the electrical energy to the housing 200 as necessary for the residential power of the electrical energy, the remaining electricity Energy is supplied to the alkaline renewable fuel cell unit 150 to be described later.

Here, the alkaline renewable fuel cell unit 150 includes an alkaline renewable fuel cell 151 and an energy storage unit 153.

That is, in the alkaline renewable fuel cell unit 150, as shown in FIG. 2A, some of the electrical energy generated by the renewable energy unit 110 is supplied to the housing 200 through the power supply unit 130. Then, hydrogen and oxygen are generated by electrolyzing the water by receiving the remaining electric energy, and as shown in FIG. And oxygen are supplied to the alkaline type renewable fuel cell 151 to generate secondary electric energy.

Therefore, mainly when the power consumption is small or the utilization rate of the renewable energy is high by converting only some of the electrical energy generated by the renewable energy unit 110 to the commercial power through the power supply unit 130 (200) ) And the remaining electrical energy is supplied to the alkaline renewable fuel cell unit 150 and used to electrolyze water.

As described above, hydrogen and oxygen generated by electrolysis of water are compressed in the form of chemical energy by the compressor 153a and stored in the storage tank 153b. When the power consumption is high or the utilization rate of the renewable energy is low, Alternatively, when the renewable energy is not available, the alkaline renewable fuel cell 151 is supplied to generate secondary electric energy.

Therefore, the secondary electric energy uses hydrogen and oxygen generated by using surplus electric energy, and it is economical and efficient because it generates fuel and oxidant by electrolyzing water without supplying a separate fuel.

Here, the alkaline renewable fuel cell unit 150 is based on an alkaline renewable fuel cell 151, and the alkaline renewable fuel cell 151 includes a hydrogen electrode 151a using pure hydrogen as fuel. An oxygen electrode 151b using pure oxygen is provided, and an electrolyte layer 151c through which ions move is provided between the hydrogen electrode 151a and the oxygen electrode 151b.

Since the alkaline regenerated fuel cell 151 uses an alkali such as potassium hydroxide as an electrolyte, the ion passing through the electrolyte is OH ^{− which} is anion. As shown in FIG. 3, an electrolysis operation method (a) And the flow direction is changed according to the fuel cell operation method (b).

In the electrolysis operation method (a), the hydrogen electrode 151a is a cathode while the oxygen electrode 151b is a cathode because some of the electrical energy generated by the water and the renewable energy system is supplied. The flow of electrons is formed from the oxygen electrode 151b in the direction of the hydrogen electrode 151a. At this time, hydrogen and oxygen generated in the hydrogen electrode 151a and the oxygen electrode 151b are respectively stored in the storage tank 153b in the form of chemical energy via a compressor 153a of the energy storage unit 153.

This process will be described with reference to Chemical Formula 1 below. As shown in Chemical Formula 1, the hydrogen electrode 151a is supplied with water and electrons to generate hydrogen and OH ^- anion, while the oxygen electrode 151b is used. In the OH ⁻ transferred from the hydrogen electrode 151a through the electrolyte layer 151c, oxygen is generated by electrochemical reaction, electrons are released, and water is incidentally generated.

Number ^{_{negative: 2H 2 O + 2e - →}} H 2 + 2OH -

Oxygen _{^{electrode: 2OH - → ½O 2 + H}} 2 O + 2e -

On the other hand, in the fuel cell operation method (b), the hydrogen electrode 151a becomes the anode and the oxygen electrode 151b becomes the cathode by the oxidation reaction of hydrogen and the reduction reaction of oxygen, and the current is the hydrogen electrode 151a. Flows to the oxygen electrode 151b to generate secondary electrical energy.

Referring to the following Formula 2, in the fuel cell operation method (b), the hydrogen electrode 151a reacts with the OH ^- anion passing through the alkaline electrolyte layer 151c to emit electrons by supplying oxygen. It acts as an anode that passes toward the pole 151b and additionally generates water. On the other hand, the oxygen electrode 151b serves as a cathode for receiving electrons transferred from an external circuit, and the electrons and the hydrated oxygen react to generate OH ^- anions to form an electrolyte layer ( It is supplied toward the hydrogen electrode 151a through 151c.

Number ^{_{negative: H 2 + 2OH - → 2H}} 2 O + 2e -

Oxygen _{electrode: ½O 2 + H 2 O +} 2e - → 2OH -

That is, the alkaline type renewable fuel cell 151 consumes less power and stores hydrogen and oxygen in the form of chemical energy through the compressor 153a when sufficient power can be supplied by the renewable energy unit 110. When power is increased and power is not supplied by the renewable energy unit 110, hydrogen and oxygen stored in chemical energy form are supplied to the hydrogen electrode 151a and the oxygen electrode 151b, respectively. The secondary electric energy is generated and re-supplied to the power supply unit 130 to supply power to the house.

The operation temperature of the alkaline type renewable fuel cell 151 is 60 to 120 ° C. at atmospheric pressure. In general, the catalyst in the hydrogen electrode 151a uses platinum-lead on silver plated with nickel, and the oxygen electrode 151b. ), Gold-platinum is used over the nickel plated metal.

Conventional alkali fuel cells are recognized as low cost fuel cells because they use inexpensive catalysts such as nickel compared to polymer electrolyte fuel cells, and are mainly used for power supply in the automotive industry. There is a problem that the electrolyte alkali such as potassium hydroxide can be carbonized because it is sensitive.

However, the alkaline renewable fuel cell 151 is used not only for residential use but also generates pure hydrogen and pure oxygen by electrolysis of water using some electrical energy supplied from the renewable energy unit 110 in connection with a renewable energy system. Since it is used as a fuel and an oxidant, respectively, it does not contain carbon dioxide, so there is no possibility that the potassium hydroxide electrolyte alkali may be carbonized.

Therefore, the alkaline renewable fuel cell unit 150 may exhibit high efficiency at low cost without separately supplying fuel, thereby implementing an economical residential renewable energy-renewable fuel cell complex system 100.

The residential renewable energy-renewable fuel cell composite system 100 is not limited to the size of the system, so it can be used in a variety of applications ranging from single-family homes that require several kW of power to large apartments that require several MW of power. have.

Furthermore, the renewable energy unit 110 generates electric energy of 0.5 to 3000kW per unit second according to the cost and durability considered first in the residential renewable energy-renewable fuel cell complex system 100. The renewable fuel cell unit 150 preferably generates secondary electric energy of 0.5 to 1000 kW per unit second.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Of course, various modifications and variations are possible within the scope of equivalent claims.

Figure 1 is a schematic diagram showing the operation of the residential renewable energy-renewable fuel cell composite system according to an embodiment of the present invention,

Figure 2a is the first renewable energy-renewable fuel cell composite system of FIG. 1 preferentially supply the electrical energy generated by the renewable energy unit to the housing, the remaining electrical energy is hydrogen through the electrolysis process of the alkaline type renewable fuel cell Figure 2b is a schematic diagram showing the case of storing in the form of chemical energy of oxygen, Figure 2b is supplying the secondary electric energy generated in the alkaline renewable fuel cell unit in the residential renewable energy-renewable fuel cell composite system of FIG. Is a schematic diagram showing a case where

Figure 3 is a schematic diagram showing the electrolysis process of water (a) and the secondary electrical energy generation process (b) by the fuel cell in the residential renewable energy-renewable fuel cell composite system of FIG.

<Description of the symbols for the main parts of the drawings>

100: Residential renewable energy-renewable fuel cell complex system

110: renewable energy department 130: power conversion unit

150: alkaline type renewable fuel cell 151: alkaline type renewable fuel cell

151a: hydrogen electrode 151b: oxygen electrode

151c: electrolyte layer 153: energy storage unit

153a: compressor 153b: storage tank

Claims (3)

In a residential energy system that generates electrical energy and supplies it to residential power, Renewable energy unit for generating electrical energy using a solar cell or a wind power generator; A power supply unit which converts some of the electrical energy generated by the renewable energy unit into commercial power and supplies the same to a residential power source; Hydrogen and oxygen are produced by electrolyzing water with the remaining electrical energy not supplied to the housing among the electrical energy generated by the new and renewable energy unit, and generating secondary electrical energy using the hydrogen and oxygen to generate the secondary unit. Residential renewable energy-renewable fuel cell complex system having an alkaline-type renewable fuel cell to supply. The method of claim 1, The alkaline renewable fuel cell unit, An alkaline type renewable fuel cell which generates electric power and hydrogen or oxygen by electrolyzing water by receiving electrical energy or generating hydrogen and oxygen; Renewable energy for residential use, characterized in that the energy storage unit for compressing and storing the hydrogen and oxygen generated in the alkaline renewable fuel cell with a compressor and resupply to the alkaline renewable fuel cell according to the user's selection Fuel cell composite system. The method of claim 1, The renewable energy unit generates electric energy in the range of 0.5 ~ 3000kW per unit second, The alkaline renewable fuel cell unit is a new renewable energy-renewable fuel cell complex system, characterized in that for generating secondary electric energy in the range of 0.5 ~ 1000kW per unit second.

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