KR102308531B1 - Electrolysis system using renewable energy and method for providing electrolysis system with the renewable energy - Google Patents

Abstract

The present invention relates to a water electrolysis system using renewable energy, and according to one embodiment, a compressed air energy storage device for compressing and storing air using electric power generated from a renewable energy source; and a water electrolysis device for receiving power from the compressed air energy storage device and producing hydrogen through a water electrolysis reaction.

Description

{Electrolysis system using renewable energy and method for providing electrolysis system with the renewable energy}

The present invention relates to a water electrolysis system, and more particularly, to a water electrolysis system capable of stably supplying energy supplied from a renewable energy source to a water electrolysis device.

In order to solve environmental problems such as global warming caused by the use of fossil fuels and the depletion of fossil resources, various alternative energy sources and technologies to use them are being developed. and commercialization has progressed rapidly.

The biggest problem with such a renewable energy source is that it is difficult to use as a stable power supply because energy is generated irregularly. In order to overcome this, recently, a technology has been developed to increase the effectiveness of a new and renewable energy source by storing renewable energy in an energy storage device and then stably supplying the stored energy to a load.

As one of the energy storage methods, a method of producing hydrogen using energy obtained from a renewable energy source in connection with a water electrolyzer, storing and selling the produced hydrogen, or using it for power generation with a fuel cell, etc. is proposed. have. In particular, as one of the fuels that can be supplied to fuel cells, hydrogen is attracting attention as a next-generation energy carrier to replace fossil fuels such as petroleum and coal. have.

However, since renewable energy sources have very large fluctuations in the amount of energy depending on climate and time, the power generation output is not constant. There is a problem in that the power accommodating capacity of the water electrolysis system must be increased inefficiently. In addition, when the water electrolysis system is operated with irregular power, the durability or performance of the water electrolysis system deteriorates, and there is a problem that it is difficult to control.

Patent Document 1: Korean Patent No. 10-1816839 (announced on January 9, 2018) Patent Document 2; Korean Patent Registration No. 10-1926010 (Announced on December 6, 2018)

The present invention has been devised to solve the problems described above, and to provide a water electrolysis system capable of supplying stable and constant power to the water electrolysis device by stabilizing the power supplied between the renewable energy source and the water electrolysis device. The purpose.

According to an embodiment of the present invention, there is provided a water electrolysis system using renewable energy, comprising: a compressed air energy storage device for compressing and storing air using electric power generated from a renewable energy source; and a water electrolysis device for receiving power from the compressed air energy storage device and producing hydrogen through a water electrolysis reaction.

According to an embodiment of the present invention, there is provided a method of supplying renewable energy to a water electrolysis system having a compressed air energy storage device for compressing and storing air and a water electrolysis device for producing hydrogen, the compressed air energy storage device has a turbine for compressing air, a compressed air tank for storing compressed air, and a first generator for generating electric power using compressed air, wherein the method uses the electric power generated from a renewable energy source to generate the turbine Compressing air by driving; storing compressed air in the compressed air tank; A first power generation step of supplying the stored compressed air to the first generator to produce electric power in the first generator; and supplying the electric power produced by the first generator to the water electrolysis device.

According to an embodiment of the present invention, by installing a compressed air energy storage device interposed between the renewable energy source and the water electrolysis device, constant and stable power is always supplied to the water electrolysis device even if the power generation output of the renewable energy source fluctuates. achieve technical effects.

As in the prior art, when power is directly supplied from a renewable energy source to a water electrolysis device, the water electrolysis device must increase its power capacity in response to irregular peak values of power, but in the water electrolysis system of the present invention, a constant power supply, so that the system capacity of the water electrolyzer can be significantly reduced. In addition, in order for the water electrolyzer to respond to irregular power, the durability and performance of the water electrolyzer deteriorate and control is difficult. It also has the advantage of improving the performance and durability of the device and enabling stable control.

1 is a block diagram of a water electrolysis system using renewable energy according to the present invention;
2 is a block diagram of a water electrolysis system using renewable energy according to the first embodiment;
3 is a view for explaining the energy efficiency of the water electrolysis system according to the first embodiment;
4 is a block diagram of a water electrolysis system using renewable energy according to a second embodiment;
5 is a view for explaining the energy efficiency of the water electrolysis system according to the second embodiment;
6 is a block diagram of a water electrolysis system using renewable energy according to a third embodiment;
7 is a view for explaining the energy efficiency of the water electrolysis system according to the third embodiment;
8 is a block diagram of a water electrolysis system using renewable energy according to the fourth embodiment.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and that the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, the terms 'comprise' and/or 'comprising' do not exclude the presence or addition of one or more other components.

Hereinafter, the present invention will be described in detail with reference to the drawings. In describing the specific examples below, various specific contents have been prepared to more specifically explain and help the understanding of the invention. However, readers with enough knowledge in this field to understand the present invention It can be recognized that it can be used without specific content. In some cases, it is mentioned in advance that parts that are commonly known in describing the invention and that are not largely related to the invention are not described in order to avoid confusion in describing the present invention.

1 is a block diagram showing the concept of a water electrolysis system using renewable energy according to the present invention.

Referring to the drawings, the water electrolysis system of the present invention is a compressed air energy storage device (CAES) 20 and a compressed air energy storage device (CAES) 20 and compressed air energy storage device (CAES) 20 for compressing and storing air using power generated from a renewable energy source 10 ( 20) and includes a water electrolysis device (SOEC) 30 for receiving power from the water electrolysis reaction to produce hydrogen.

Renewable energy is energy used by recycling existing fossil fuels or converting renewable energy. Although the drawing shows a wind power plant as a renewable energy source 10, this is exemplary and the water electrolysis system of the present invention can use one or more of energy such as solar, solar, wind, hydro, and geothermal as renewable energy. have.

The compressed air energy storage system (CAES) 20 stores compressed air by compressing the air with the electric power produced by the renewable energy source 10, and when necessary, the compressed air is used to produce electricity, and the electricity is received and transmitted. supply to the device 30 . In general, since renewable energy sources such as solar and wind power do not have a constant power generation output, in the present invention, compressed air energy is stored at the front end of the water electrolysis device 30 as a device for stabilizing the supply power supplied to the water electrolysis device 30 . A device 20 is provided.

The water electrolysis device 30 receives water (steam) and electric power and produces hydrogen and oxygen by a water electrolysis reaction, for example, at a high temperature such as a Solid Oxide Electrolysis Cell (SOEC) (for example, Celsius It can be implemented with any electrolytic device operating at 600 degrees or higher).

The water electrolyzer 30 is installed in a water electrolysis cell stack including an anode and a cathode, a flow path for supplying water (steam) to the water electrolysis cell stack, a flow path for transporting exhaust gas discharged from the water electrolysis cell stack, and each flow path It may be composed of components such as a heat exchanger, a heater, a pump and/or a blower, and the general structure of the water electrolysis device is known in the art, so a detailed description thereof will be omitted.

In the water electrolysis system configuration according to the present invention, when the power generation output of the renewable energy source 10 is high, the compressed air energy storage device 20 compresses and stores the air using the generated power of the renewable energy source 10 . do. In this case, some of the power produced by the renewable energy source 10 may be directly supplied to the water electrolysis device 30 . When the power generation output of the renewable energy source 10 is low, the power supplied directly from the renewable energy source 10 to the water electrolysis device 30 is reduced or cut off, and the compressed air energy storage device 20 produces power to receive power. and supplied to the device 30 . That is, electricity can be produced by rotating the turbine of the generator using the stored compressed air, and the produced electricity can be supplied to the water electrolysis device 30 . By providing the compressed air energy storage device 20 at the front end of the water electrolysis device 30 as described above, even if the power generation output of the energy source 10 fluctuates, constant and stable power can be always supplied to the water electrolysis device 30 do.

A water electrolysis system according to various embodiments of the present invention will now be described with reference to FIGS. 2 to 8 .

2 is a block diagram schematically illustrating a water electrolysis system using renewable energy according to the first embodiment. The water electrolysis system of the first embodiment includes a first compressed air energy storage device 21 and a water electrolysis device 30 .

In one embodiment, the first compressed air energy storage device 21 is a turbine 210, a heat storage unit 220, a compressed air tank 230, a generator 240, and a compressed air movement flow path between these components and each It may include one or more valves (V1, V2) installed in the flow path, and the like.

In one embodiment, the turbine 210 compresses air supplied from the outside through the first flow path P1 using the motor 211 . At this time, the motor 211 may be driven using the power generated from the renewable energy source 10 . In order to reduce the compression power when generating compressed air, the air can be compressed by repeating the compression and cooling process in multiple stages. However, in this case, energy loss occurs because most of the heat generated during compression is discarded. Therefore, in a preferred embodiment, air compression is performed at one time without intermediate cooling. That is, compressed air is generated through adiabatic compression that does not receive heat from the outside or dissipate heat to the outside.

In one embodiment, when air is compressed by adiabatic compression without intermediate cooling, the compressed air is heated to approximately 600 degrees Celsius. The heated compressed air passes through the heat storage unit 220 through the second flow path P2 , transfers thermal energy to the heat storage unit 220 , and is then transferred to and stored in the compressed air tank 230 .

The heat storage unit 220 serves to absorb and store thermal energy from the compressed air supplied to the compressed air tank 230 and heat the compressed air discharged from the compressed air tank 230 with the stored thermal energy.

The heat storage unit 220 may be configured in the form of a container having a heat storage material having heat storage characteristics, such as, for example, a ceramic substrate. For example, the heat storage unit 220 may be configured by filling a container with a plurality of heat storage materials having a gravel, ball shape, or honeycomb structure. Accordingly, the heat storage unit 220 may store the thermal energy by transferring the heat energy of the compressed air to the heat storage material while the high-temperature compressed air passes through the heat storage unit 220 . In addition, when the low-temperature compressed air passes through the heat storage unit 220, the compressed air can be heated by heat exchange between the low-temperature compressed air and the heat storage material.

The low-temperature compressed air cooled while passing through the heat storage unit 220 is stored in the compressed air tank 230 , and then discharged by a predetermined amount toward the third flow path P3 as necessary. The operation of supplying air to the compressed air tank 230 through the second flow path P2 and the operation of discharging the compressed air through the third flow path P3 are performed by the first valve V1 installed in each flow path P2 and P3. ) and the operation of the second valve V2. For example, by opening the first valve V1 and closing the second valve V2, compressed air can be transferred to the compressed air tank 230 through the second flow path P2, and the first valve V1 is closed. And by opening the second valve (V2) it is possible to discharge the compressed air of the compressed air tank 230 to the third flow path (P3).

The use of the first and second valves V1 and V2 in this way is an exemplary configuration for conveying compressed air, and in an alternative embodiment, for example, a three-way valve is used instead of the first and second valves V1 and V2. It is also possible to control this airflow. In addition, although not shown in the drawings, for example, a regulator may be installed in the third flow path P3 , and the pressure of the compressed air may be constantly maintained by the regulator and discharged to the third flow path P3 .

The low-temperature compressed air discharged from the compressed air tank 230 is heated by receiving thermal energy from the heat storage unit 220 . When the heat storage unit 220 is made of a heat storage material such as a ceramic cover, since the heat exchange efficiency of the ceramic cover 95 is generally 90% or more, even if the compressed air undergoes cooling and heating in the heat storage unit 220, the thermal energy is greatly increased. It can be heated with sufficiently high temperature compressed air without loss.

The compressed air heated by the heat storage unit 220 is transferred through the third flow path P3 and supplied to the generator 240 . The generator 240 is a device for generating electric power using high-temperature compressed air, and may include, for example, a turbine 241 and a generator 242 . The turbine 241 performs a mechanical work of driving the shaft of the turbine by high-temperature compressed air, and the generator 242 converts the mechanical energy of the turbine into electrical energy to produce electricity.

The electricity produced by the generator 240 is supplied to the water electrolysis device 30 . As described with reference to FIG. 1 , the water electrolysis device 30 receives water (steam) and electric power and produces hydrogen and oxygen through a water electrolysis reaction, and operates at a high temperature such as, for example, a solid oxide water electrolysis cell (SOEC). It can be implemented with any water electrolysis device.

3 is a view showing exemplary energy efficiency when the water electrolysis system according to the first embodiment is tested. FIG. 3 (a) is an entropy diagram, and FIG. 3 (b) is each point ( Physical properties such as temperature and pressure of compressed air in P1 to P4) and the calculated energy efficiency of the water electrolysis system are shown. At this time, the energy efficiency was calculated assuming that the compressor efficiency of the turbine 210 and the expander efficiency of the turbine 241 are respectively 85%.

In FIGS. 3(a) and 3(b), each point P1 to P4 corresponds to each flow path P1 to P4 of FIG. 2 and indicates the state of the air in each flow path P1 to P4. That is, when referring to FIGS. 2 and 3 , it can be seen that the air in the first flow path P1 has a pressure of 1 bar and a temperature of 30 degrees Celsius.

Referring to the drawings, the arrow from the first point P1 to the second point P2 in FIG. 3(a) indicates that the air at 30 degrees Celsius of 1 bar in the first flow path P1 of FIG. 2 moves the turbine 210. Corresponds to being compressed as it passes through and becomes compressed air at 800 degrees Celsius and 70 bar. In this case, since entropy increases in all transformation processes, it will be understood that the arrow from the first point P1 to the second point P2 is slightly inclined to the right rather than vertical.

This compressed air is cooled in the heat storage unit 220 and stored in the compressed air tank 230 , and then, when discharged from the compressed air tank 230 , becomes a constant pressure of approximately 50 bar while passing through a regulator (not shown), and the heat storage unit It passes through 220 and is heated to 780 degrees Celsius. In FIG. 3(a), the arrow pointing from the third point P3 to the fourth point P4 indicates that the air in the third flow path P3 of FIG. 2 is discharged to the fourth flow path P4 through the generator 240. respond to That is, the high-temperature compressed air of 780 degrees Celsius and 50 bar expands in the generator 240 and after performing mechanical work, the temperature and pressure drop to approximately 203 degrees Celsius and 1 bar, and are discharged to the fourth flow path P4. Since entropy also increases in this process, the arrow from the third point P3 to the fourth point P4 is inclined to the right.

Comparing the first point (P1) and the fourth point (P4) in Fig. 3(a), the first point (P1) and the fourth point (P4) are the same due to the irreversibility of compression/expansion due to an increase in entropy It is not a position and energy is lost. That is, as much energy as the path from the fourth point P4 to the first point P1 is lost.

Referring to Figure 3 (b), the power (Wc) consumed in the compression operation of the turbine 210 during the experiment of this water electrolysis system is 839.55 kilowatts, produced by the expansion operation of the turbine 241 of the generator 240 The power (We) is 631.99 kilowatts, resulting in an energy efficiency (We/Wc) of 75.3%. The remainder (24.7%) is energy loss due to the irreversibility of compression/expansion with increasing entropy.

As described above, the water electrolysis system using renewable energy according to the first embodiment of FIGS. 2 and 3 includes a first compressed air energy storage device 21 at the front end of the water electrolysis device 30 to provide a renewable energy source ( Even if the power generation output of 10) fluctuates, a technical effect of always supplying constant and stable power to the water electrolyzer 30 is obtained. That is, electricity is produced by discharging a certain amount of compressed air from the compressed air tank 230 at a constant pressure and supplied to the water electrolysis device 30 , so that the water electrolysis device 30 can produce a certain amount of hydrogen for 24 hours.

In addition, as in the prior art, when the water electrolysis device 30 is directly supplied with power from the renewable energy source 10, the water electrolysis device 30 must have a large power accommodating capacity in response to the irregular peak value of power, but in the embodiment of the present invention Since constant power can be supplied in the , it is possible to significantly reduce the system capacity of the electrolytic device 30 . Furthermore, when the water electrolysis device 30 is operated with irregular power, the durability and performance of the water electrolysis device deteriorate and control is difficult. There is also the advantage of improved and stable control.

4 is a block diagram schematically illustrating a water electrolysis system using renewable energy according to a second embodiment. The water electrolysis system of the second embodiment includes a second compressed air energy storage device 22 and a water electrolysis device 30 .

In one embodiment, the second compressed air energy storage device 22 includes a turbine 210 , a heat storage unit 220 , a compressed air tank 230 , a generator 240 , a heat exchanger 250 , and between these components. It may include a compressed air movement passage and one or more valves (V1, V2) installed in each flow passage, and the like.

Compared with the first compressed air energy storage device 21 of FIG. 2 , the second compressed air energy storage device 22 of FIG. 4 is different in that it further includes a heat exchanger 250 , and the remaining components are shown in FIG. 2 . Since the components are the same as or similar to those of , a description thereof will be omitted.

The heat exchanger 250 is disposed between the heat storage unit 220 and the generator 240 so that compressed air discharged from the heat storage unit 220 passes through the heat exchanger 250 . The heat exchanger 250 includes a closed path L1 through which the heat medium fluid flows, and the closed path L1 is configured to circulate between the heat exchanger 250 and the water electrolysis device 30 .

The high-temperature compressed air supplied to the heat exchanger 250 through the third flow path P3 exchanges heat with the heat medium fluid in the heat exchanger 250 to heat the heat medium fluid. The heated heating medium fluid flows to the water electrolysis device 30 along the closed path L1 to supply thermal energy to the water electrolysis device 30 . At this time, preferably, the temperature of the compressed air discharged from the heat storage unit 220 and supplied to the heat exchanger 250 may be between 750° C. and 900° C., and the heat energy is transferred from the heat exchanger 250 to the heat medium fluid. And the temperature of the reduced compressed air may be between 550 degrees Celsius to 700 degrees Celsius.

The heating medium fluid heated in the heat exchanger 250 supplies thermal energy necessary for the operation of the water electrolysis device 30 . The thermal energy supplied to the water electrolysis device 30 through the heating medium fluid may be used in various forms. For example, it can be used to increase the temperature of the atmosphere inside the water electrolysis device 30 or the temperature of the water electrolysis cell stack to maintain the water electrolysis operation temperature or to keep it constant at a high temperature and/or to the water electrolysis device 30 . It can be used to heat the supplied water to steam or to preheat steam. Since the high-temperature water electrolysis device can reduce the power energy required for water electrolysis by the amount of heat energy supplied, high-efficiency water electrolysis is possible using waste heat.

The temperature of the heating medium fluid supplied to the water electrolysis device 30 is not necessarily higher than the operating temperature of the water electrolysis device 30 , but may be slightly lower than that. In one embodiment, the temperature of the fluid in the heat medium supplied to the water electrolysis device 300 may be about 150 degrees lower than the operating temperature of the water electrolysis device 30. For example, when the operating temperature of the water electrolysis device is 700 degrees Celsius, the heat medium If the temperature of the fluid is 550 degrees or more, as another example, when the operating temperature of the water electrolysis device is 600 degrees Celsius, it is sufficient if the temperature of the heating medium fluid is 450 degrees or more.

5 is a view showing an exemplary energy efficiency when the water electrolysis system according to the second embodiment is tested. FIG. 5 (a) is an entropy diagram, and FIG. 5 (b) is each point ( Physical properties such as temperature and pressure of compressed air in P1 to P5) and the calculated energy efficiency of the water electrolysis system are shown. At this time, the energy efficiency was calculated assuming that the compressor efficiency of the turbine 210 and the expander efficiency of the turbine 241 are respectively 85%. In addition, in FIGS. 5(a) and 5(b), each point P1 to P5 corresponds to each flow path P1 to P5 in FIG. 4 and indicates the state of air in each flow path P1 to P5.

Referring to the drawings, as indicated by the arrow from the first point (P1) to the second point (P2) in Fig. 5 (a), air at 30 degrees Celsius of 1 bar passes through the turbine 210 and is compressed to 800 degrees Celsius and 70 bar. of compressed air, and then stored in the compressed air tank 230 through the heat storage unit 220 .

Compressed air discharged from the compressed air tank 230 is 780 degrees centigrade 50 bar after passing through the heat storage unit 220 (the third point (P3)), and is removed from the third point (P3) in FIG. As indicated by the arrow at the 4 point P4, heat energy is transferred from the heat exchanger 250 to the heating medium fluid, and the temperature is 570 degrees Celsius and 50 bar.

After that, as indicated by the arrow from the fourth point (P4 to the fifth point (P5) in Fig. 5(a), compressed air is supplied to the generator 240 and expanded and used for power generation, and the The pressure drops and is discharged to the outside through the fifth flow path P5.

Referring to Fig. 5 (b), in the water electrolysis system of the second embodiment, the power (Wc) consumed for the compression operation of the turbine 210 is 839.55 kilowatts, which is the power consumption (Wc) of the first embodiment of Fig. 3 same as However, in the second embodiment, the energy Q transferred to the water electrolysis device 30 through the heat exchanger 250 is 238.54 kilowatts, and the electric power We produced by the expansion operation of the generator turbine 241 is 498.81 kilowatts, respectively. was calculated, and thus energy efficiency ((We+Q)/Wc) was calculated to be 87.8%.

Compared with the experimental results of the first embodiment of Figure 3, since the temperature of the compressed air used in the generator 240 is lowered, the ratio of the power recovered when the turbine 241 is expanded to the power required for the compression of the turbine 210 (We/ Wc) is 59.4%, which is reduced compared to the first embodiment, but since the thermal energy Q of the compressed air is additionally supplied to the water electrolysis device 30 through the heat exchanger 250, the total supply to the water electrolysis device 30 is The energy efficiency (87.8%) was higher than that of the first embodiment (75.3%). That is, by utilizing the high-temperature thermal energy generated from the compressed air energy storage device 22 to supply the water electrolysis device 30, it is possible to minimize the thermal energy wasted due to the irreversibility of compression/expansion, which is higher than in the first embodiment. Energy can be supplied to the water electrolysis device 30 with energy efficiency.

6 is a block diagram schematically illustrating a water electrolysis system using renewable energy according to a third embodiment. The water electrolysis system of the third embodiment includes a third compressed air energy storage device 23 and a water electrolysis device 30 .

In one embodiment, the third compressed air energy storage device 23 is a turbine 210 , a first heat storage unit 220 , a compressed air tank 230 , a generator 240 , a heat exchanger 250 , and a second heat storage unit 260, and one or more valves (V1, V2) installed in each flow passage and the compressed air movement passage between these components, and the like.

The first heat storage unit 220 of FIG. 6 is the same as the heat storage unit 220 of FIG. 4 , and thus the third compressed air energy storage device of FIG. 6 is compared with the second compressed air energy storage device 21 of FIG. 4 . Reference numeral 22 is different in that it further includes the second heat storage unit 260 , and the remaining components are the same as or similar to those of FIG. 2 , so a description thereof will be omitted.

The second heat storage unit 260 is disposed so that the first flow path P1 and the fifth flow path P5 pass through, and the configuration of the second heat storage unit 260 is, for example, the same as or similar to that of the first heat storage unit 220 . A heat storage material having heat storage characteristics, such as a ceramic tint, may be implemented in a structure in which the container is filled.

According to this third embodiment, the second heat storage unit 260 absorbs and stores thermal energy from the air discharged from the generator 240 to the fifth flow path P5, and uses the stored thermal energy to supply air to the turbine 210. can be heated. That is, by using the waste heat of the air of the fifth flow path P5 to heat the air of the first flow path P1 , the waste heat of the compressed air energy storage device 23 is maximized.

Therefore, for example, even if the compression ratio is not higher than 50 for high-temperature heat storage, the water electrolysis system of the present invention can be implemented by using the compressed air energy storage device 23 of the third embodiment.

7 is a view showing exemplary energy efficiency when the water electrolysis system according to the third embodiment is tested. FIG. 7 (a) is an entropy diagram, and FIG. 7 (b) is each point ( Physical properties such as temperature and pressure of compressed air in P1 to P5) and the calculated energy efficiency of the water electrolysis system are shown. At this time, the energy efficiency was calculated assuming that the compressor efficiency of the turbine 210 and the expander efficiency of the turbine 241 are respectively 85%. In addition, in FIGS. 7(a) and 7(b), each point P1 to P5 corresponds to each flow path P1 to P5 in FIG. 6 and indicates the state of air in each flow path P1 to P5.

Referring to the drawing, the air supplied from the outside is preheated to about 120 degrees Celsius through the second heat storage unit 260 to reach the first point P1. After that, as shown by the arrow from the first point (P1) to the second point (P2), when the turbine 210 compresses it to 40bar Celsius, the temperature rises to 900 degrees Celsius.

Compressed air discharged from the compressed air tank 230 passes through the first heat storage unit 220 and then becomes 870 degrees Celsius 25 bar (the third point P3), and the third point P3 to the fourth point P4 ), as indicated by the arrow, the heat energy is transferred from the heat exchanger 250 to the heating medium fluid, and the temperature is 550 degrees Celsius and 25 bar.

After that, the compressed air is supplied to the generator 240 and used for power generation as indicated by the arrow from the fourth point (P4 to the fifth point (P5)), and the temperature and pressure drop to about 140 degrees Celsius and 1 bar. This air is the fifth It is supplied to the second heat storage unit 260 through the flow path P5 and is used to heat the air in the first flow path P1 in the second heat storage unit 260 and then discharged to the outside.

Referring to FIG. 7( b ), the power (Wc) consumed in the compression operation of the turbine 210 in the water electrolysis system of the third embodiment is 850.76 kilowatts, transmitted to the water electrolysis device 30 through the heat exchanger 250 Energy (Q) was calculated to be 364.63 kilowatts, and electric power (We) produced by the generator turbine 241 was calculated to be 433.04 kilowatts, respectively, and thus energy efficiency ((We+Q)/Wc) was calculated to be 93.8%. This value is higher than the energy efficiency (87.8%) of the second embodiment of FIG. 5 , and waste heat of air discharged to the outside through the fifth flow path P5 is used to heat the air in the first flow path P1 . By doing so, since the waste heat of the compressed air energy storage device 23 is maximally utilized, higher energy efficiency is obtained.

8 is a block diagram schematically illustrating a water electrolysis system using renewable energy according to a fourth embodiment. The water electrolysis system of the fourth embodiment includes a fourth compressed air energy storage device 24 and a water electrolysis device 30 .

In one embodiment, the fourth compressed air energy storage device 24 is a turbine 210 , a first heat storage unit 220 , a compressed air tank 230 , a first generator 240 , a heat exchanger 250 , and a third It may include a heat storage unit 270, a second generator 280, and one or more valves (V1, V2) installed in the compressed air movement flow path and each flow path between these components.

The first heat storage unit 220 and the first generator 240 of FIG. 8 are the same as the heat storage unit 220 and the generator 240 of FIG. 4, respectively, and thus the second compressed air energy storage device 22 of FIG. Compared with , the fourth compressed air energy storage device 24 of FIG. 8 is different in that it further includes a third heat storage unit 270 and a second generator 280, and the remaining components are the components of FIG. Since they are the same or similar, a description thereof will be omitted.

The third heat storage unit 270 and the second generator 280 are sequentially disposed on a flow path connecting the first heat storage unit 220 and the heat exchanger 250 . The third heat storage unit 270 further heats the compressed air discharged from the first heat storage unit 220 . The third heat storage unit 270 may be implemented in a structure in which a heat storage material having a heat storage characteristic, such as a ceramic coating, is filled in a container, for example, by using an electric heater 271 as shown in the figure. 270) can be heated to a predetermined temperature to keep it constant. The second generator 280 is configured to produce electric power using compressed air heated by the third heat storage unit 270, and may include, for example, a turbine 281 and a generator 282 connected thereto, as shown. .

In an embodiment, the compressed air discharged from the first heat storage unit 220 may be heated at, for example, approximately 1500 degrees Celsius in the third heat storage unit 270 . The heated air passes through the second generator 280 and the temperature is reduced to about 800 to 900 degrees Celsius to produce electricity, and this electrical energy is supplied to the water electrolysis device 30 . The compressed air discharged from the second generator 280 passes through the heat exchanger 250 and transfers some energy to the heating medium fluid and is cooled to approximately 600 to 700 degrees Celsius. After that, this compressed air is transferred to the first generator 240 and used to produce electricity, and then discharged to the outside, and the produced electricity may be supplied to the water electrolysis device 30 .

As described above, when the third heat storage unit 270 is further installed in the fourth embodiment to heat the compressed air to a high temperature, the energy density can be increased, and when the load fluctuation of the renewable energy source 10 is severe, the turbine 210 ), there is an advantage of improving the responsiveness by using the electric heater 271 rather than controlling the driving.

As described above, those of ordinary skill in the art to which the present invention pertains can understand that various modifications and variations are possible from the description of this specification. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the following claims as well as the claims and equivalents.

10: Renewable energy source
20, 21, 22, 23, 24: compressed air energy storage device
30: water electrolysis device
210: turbine
220, 260, 270: heat storage unit
230: compressed air tank
240, 280: generator
250: heat exchanger

Claims (12)

delete delete As a water electrolysis system using renewable energy,
Compressed air energy storage device 20 for compressing and storing air using the power generated from a renewable energy source; and
and a water electrolysis device 30 that receives power from the compressed air energy storage device and produces hydrogen by a water electrolysis reaction,
The compressed air energy storage device 20,
a turbine 210 for compressing air using the power generated from the renewable energy source;
a compressed air tank 230 for storing compressed air compressed in the turbine;
a first heat storage unit 220 for absorbing and storing thermal energy from the compressed air supplied to the compressed air tank and heating the compressed air discharged from the compressed air tank with the stored thermal energy;
a first generator 240 for generating electric power using compressed air heated by the first heat storage unit;
a heat exchanger 250 disposed between the first heat storage unit and the first generator; and
and a closed path (L1) through which a heat medium fluid circulating between the heat exchanger and the water electrolysis device flows,
In the heat exchanger, heat exchange between the compressed air discharged from the first heat storage unit and the heat medium fluid to heat the heat medium fluid, and the heated heat medium fluid supplies heat energy to the water electrolysis device using renewable energy water electrolysis system. 4. The method of claim 3,
The temperature of the compressed air discharged from the first heat storage unit and supplied to the heat exchanger is 750 to 900 degrees Celsius, and the temperature of the compressed air heat-exchanged with the heat medium fluid in the heat exchanger is 550 to 700 degrees Celsius. Water electrolysis system using energy. 4. The method of claim 3,
Water electrolysis using renewable energy, characterized in that it further comprises a second heat storage unit 260 for absorbing and storing thermal energy from the air discharged from the first generator and heating the air supplied to the turbine with the stored thermal energy. system. 4. The method of claim 3,
Further comprising a third heat storage unit 270 and a second generator 280 sequentially disposed between the first heat storage unit and the heat exchanger,
The third heat storage unit heats the compressed air discharged from the first heat storage unit, and the second generator uses the compressed air heated by the third heat storage unit to generate electric power. Renewable energy water electrolysis system using 7. The method of claim 6,
Water electrolysis system using renewable energy, characterized in that configured to supply the electric power produced by the second generator to the water electrolysis device. delete delete A method of supplying renewable energy to a water electrolysis system having a compressed air energy storage device for compressing and storing air and a water electrolysis device for producing hydrogen, the method comprising:
The compressed air energy storage device absorbs and stores thermal energy from a turbine for compressing air, a compressed air tank for storing compressed air, and compressed air supplied to the compressed air tank, and is discharged from the compressed air tank as the stored thermal energy. a first heat storage unit for heating compressed air, a first generator for generating electric power using compressed air, and a heat exchanger disposed between the first heat storage unit and the first generator; and a closed path (L1) through which a heat medium fluid circulating between the heat exchanger and the water electrolysis device flows,
The method is
Compressing air by driving the turbine with power generated from a renewable energy source;
storing compressed air in the compressed air tank;
a first power generation step of supplying the stored compressed air to the first generator to produce electric power in the first generator;
supplying the electric power produced by the first generator to the electrolysis device;
heating the heating medium fluid by exchanging heat between the compressed air discharged from the first heat storage unit and the heating medium fluid in the heat exchanger; and
supplying thermal energy to the water electrolyzer by the heated heating medium fluid;
A method of supplying renewable energy to a water electrolysis system, including. 11. The method of claim 10,
The compressed air energy storage device further comprises a second heat storage unit 260 for absorbing and storing thermal energy from the air discharged from the first generator and heating the air supplied to the turbine with the stored thermal energy. A method of supplying renewable energy to the water electrolysis system. 11. The method of claim 10,
The compressed air energy storage device further includes a third heat storage unit 270 and a second generator 280 that are sequentially disposed between the first heat storage unit and the heat exchanger,
said method,
heating the compressed air discharged from the first heat storage unit in the third heat storage unit;
generating electric power in the second generator using the compressed air heated by the third heat storage unit; and
Supplying the generated power to the water electrolysis device; method for supplying renewable energy to the water electrolysis system, characterized in that it further comprises.

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