Power generation systems and power generation equipment

Abstract

This system provides an energy generation system that utilizes the cold energy generated by the phase change and temperature change of hydrogen. [Solution] The first power generation device includes a first refrigerant pump for supplying a first refrigerant in a liquid state, a first heat exchanger for evaporating the first refrigerant in a liquid state and performing heat exchange, a first power generation unit driven by the first refrigerant in a gaseous state to generate electricity, and a second heat exchanger for condensing the first refrigerant in a gaseous state having a boiling point higher than that of hydrogen and performing heat exchange, and a hydrogen supply unit for supplying hydrogen to the second heat exchanger. The first power generation unit is configured to generate electricity within a steam cycle that uses the cold energy generated by the change in the state and temperature of hydrogen as a result of heat exchange between hydrogen and the first refrigerant in a gaseous state by the second heat exchanger.

Description

Technical Field

[0001] The present invention relates to a power generation system, and particularly to a power generation system and a power generation device that utilize the cooling and heating energy generated by the state change and temperature change of hydrogen.

Background Art

[0002] Conventionally, an air separation device that utilizes the cooling and heating energy generated by the state change and temperature change of liquid hydrogen has been known (for example, see Patent Document 1).

[0003] Patent Document 1 discloses a main heat exchanger through which liquid hydrogen supplied from a source of liquid hydrogen flows through a liquid hydrogen supply pipe. This main heat exchanger cools the raw air flowing through the pipe by the cooling heat generated when the liquid hydrogen evaporates. Further, Patent Document 1 discloses a distillation column that separates each of liquid oxygen and nitrogen gas from the cooled raw air. Further, Patent Document 1 discloses a heat exchanger that performs heat exchange between liquid hydrogen and the nitrogen gas generated in the distillation column. In Patent Document 1, when heat exchange between liquid hydrogen and nitrogen gas is performed by the heat exchanger, liquid nitrogen is generated by cooling the nitrogen gas by the cooling heat of the liquid hydrogen.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, in Patent Document 1, liquid nitrogen is produced when the nitrogen gas is cooled by the cold energy of the liquefied hydrogen during heat exchange between liquefied hydrogen and nitrogen gas using a heat exchanger. Although not described in Patent Document 1, liquefied hydrogen is generally transported by large ships such as ocean tankers. Electric equipment such as electric pumps is used to transport the liquid hydrogen to vaporize it. In other words, a large amount of energy is used for the transport and vaporization of liquefied hydrogen, so it is desirable to be able to generate at least a portion of the energy required to vaporize the liquefied hydrogen. For this reason, there is a need for a system (device) that can generate energy using the cold energy generated by the change in the state and temperature of hydrogen.

[0006] This invention was made to solve the above-mentioned problems, and one of its objectives is to provide a system and power generation device capable of generating energy using the cold energy generated by the phase change and temperature change of hydrogen. [Means for solving the problem]

[0007] To achieve the above objective, the power generation system in the first aspect of this invention comprises a first power generation device including a first refrigerant pump for supplying a first refrigerant in a liquid state, a first heat exchanger for evaporating the first refrigerant in a liquid state and performing heat exchange, a first power generation unit driven by the first refrigerant in a gaseous state to generate electricity, and a second heat exchanger for condensing the first refrigerant in a gaseous state having a boiling point higher than the boiling point of hydrogen and performing heat exchange, and a hydrogen supply unit for supplying hydrogen to the second heat exchanger, wherein the first power generation unit is configured to generate electricity within a steam cycle using cold energy generated by the change in the state and temperature of hydrogen as a result of heat exchange between hydrogen and the first refrigerant in a gaseous state by the second heat exchanger.

[0008] To achieve the above objective, the power generation device in the second aspect of this invention comprises a first refrigerant pump for supplying a first refrigerant in a liquid state, a first heat exchanger for evaporating the first refrigerant in a liquid state and performing heat exchange, a first power generation unit driven by the first refrigerant in a gaseous state to generate electricity, and a second heat exchanger for condensing the first refrigerant in a gaseous state having a boiling point higher than that of hydrogen and performing heat exchange, wherein the first power generation unit is configured to generate electricity within a steam cycle using cold energy generated by the change in the state of hydrogen and the temperature change caused by the heat exchange between hydrogen and the first refrigerant in a gaseous state by the second heat exchanger. [Effects of the Invention]

[0009] As described above, the first power generation unit generates electricity within a steam cycle that utilizes the cold energy generated by the change in hydrogen's state and temperature through heat exchange between hydrogen and the first gaseous refrigerant in the second heat exchanger. This configuration allows the steam cycle to utilize the cold energy generated by the change in hydrogen's state and temperature. As a result, it is possible to generate electrical energy using the cold energy generated by the change in hydrogen's state and temperature. Consequently, a power generation system and power generation device capable of generating energy using the cold energy generated by the change in hydrogen's state and temperature can be provided. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram of a power generation system according to a first embodiment of the present invention. [Figure 2] This is a ph diagram of a power generation system according to a first embodiment of the present invention. [Figure 3] This is a diagram of a power generation system according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0011] [First Embodiment] Hereinafter, an embodiment of the present invention will be described based on the drawings.

[0012] (Overall configuration of the power generation system) A power generation system 200 according to a first embodiment of the present invention will be described with reference to Figures 1 and 2.

[0013] As shown in Figure 1, the power generation system 200 according to the first embodiment includes a nitrogen refrigerant power generation device 100 driven by nitrogen as a refrigerant, a seawater circulation device 110, and a hydrogen vaporizer 120. The nitrogen refrigerant power generation device 100 is an example of the "first power generation device" or "power generation device" in the claims, and nitrogen is an example of the "first refrigerant" in the claims.

[0014] (Configuration of nitrogen refrigerant power generation system) The nitrogen refrigerant power generation device 100 comprises a nitrogen pump 10, a nitrogen evaporator 20, a nitrogen power generation unit 30, a nitrogen condenser 40, and a nitrogen tank 50. The nitrogen pump 10 is an example of the "first refrigerant pump" in the claims, the nitrogen evaporator 20 is an example of the "first heat exchanger" in the claims, the nitrogen power generation unit 30 is an example of the "first power generation unit" in the claims, and the nitrogen condenser 40 is an example of the "second heat exchanger" in the claims.

[0015] Furthermore, the nitrogen tank 50 and the nitrogen pump 10 are connected by piping 1a. The nitrogen pump 10 and the nitrogen evaporator 20 are connected by piping 1b. The nitrogen evaporator 20 and the nitrogen power generation unit 30 are connected by piping 1c. The nitrogen power generation unit 30 and the nitrogen condenser 40 are connected by piping 1d. The nitrogen condenser 40 and the nitrogen tank 50 are connected by piping 1e. Liquid or gaseous nitrogen flows as a refrigerant inside piping 1a to 1e. In addition, insulating material (not shown) is placed outside piping 1a to 1e.

[0016] The nitrogen pump 10 is used as a compressor and is configured to compress the liquid nitrogen flowing through piping 1a and to supply it to the nitrogen evaporator 20 via piping 1b. The nitrogen pump 10 is also controlled by an inverter (not shown). This allows the nitrogen pump 10 to adjust the flow rate of liquid nitrogen discharged from it.

[0017] The nitrogen evaporator 20 is configured to evaporate high-pressure liquid nitrogen in piping 1b, which is pumped by the nitrogen pump 10, using seawater introduced by the seawater circulation device 110, which will be described later. In other words, the nitrogen evaporator 20 facilitates heat exchange between seawater (high temperature) and liquid nitrogen (low temperature). The nitrogen evaporator 20 is, for example, a shell-and-tube heat exchanger. The nitrogen evaporated by the nitrogen evaporator 20 is sent to piping 1c.

[0018] The nitrogen power generation unit 30 includes a turbine 30a and a generator 30b, and is configured to generate alternating current power. The turbine 30a is configured to rotate by using the energy released from gaseous nitrogen, which is expanded to a low-pressure state by expanding the high-pressure gaseous nitrogen flowing through the pipe 1c. The generator 30b is configured to convert the rotational energy generated by the rotation of the turbine 30a into electrical energy and output it as alternating current power.

[0019] The nitrogen condenser 40 is configured to condense gaseous nitrogen in the pipe 1d that has passed through the turbine 30a by using hydrogen introduced by a hydrogen vaporizer 120 described later. Further, the nitrogen condenser 40 also serves as an evaporator that evaporates hydrogen in the hydrogen vaporizer 120. That is, the nitrogen condenser 40 performs heat exchange between gaseous nitrogen (high temperature) and liquid hydrogen (low temperature) to condense nitrogen and evaporate hydrogen. The nitrogen condenser 40 is, for example, a shell & tube heat exchanger. The nitrogen condensed by the nitrogen condenser 40 is sent into the pipe 1e. In the first embodiment, the flow rate of nitrogen flowing through the nitrogen condenser 40 is made larger than the amount of hydrogen flowing through the nitrogen condenser 40. As a result, although the freezing point of nitrogen flowing through the nitrogen condenser 40 is about -210°C, even when heat exchange is performed with liquid hydrogen (-253°C), it flows as a liquid without freezing.

[0020] The nitrogen tank 50 is configured to temporarily store the liquid nitrogen discharged from the nitrogen condenser 40. Thereby, the nitrogen tank 50 has a function as an accumulator that makes the pressure in the nitrogen refrigerant power generation device 100 approach a constant pressure even when, for example, fluctuations occur in the nitrogen power generation unit 30 or a load (not shown) that uses the generated electric power.

[0021] (Configuration of seawater introduction device) The seawater circulation device 110 includes a seawater pump 60 for introducing seawater into the nitrogen evaporator 20 of the nitrogen refrigerant power generation device 100. The seawater circulation device 110 also includes a pipe 2a connecting the sea and the seawater pump 60, a pipe 2b connecting the seawater pump 60 and the nitrogen evaporator 20, and a pipe 2c connecting the nitrogen evaporator 20 and the sea. The seawater pump 60 is, for example, a vortex pump and is configured to continuously pump seawater through the pipe 2a. Note that the seawater used in the first embodiment is used as it is without heating or cooling the seawater existing in the sea. Therefore, the temperature of the seawater is higher than that of the liquid nitrogen. Further, since the nitrogen evaporator 20 performs heat exchange between the seawater (high temperature) and the liquid nitrogen (low temperature), the temperature of the seawater discharged from the pipe 2c to the sea is lower than the temperature of the seawater flowing through the pipe 2b.

[0022] (Configuration of Hydrogen Vaporization Device) The hydrogen vaporization device 120 includes a hydrogen pump 70 and a heater 80. Specifically, the hydrogen vaporization device 120 includes a hydrogen pump 70 for introducing liquid hydrogen into the nitrogen condenser 40 of the nitrogen refrigerant power generation device 100, and a heater 80 for heating gaseous hydrogen to room temperature. The hydrogen vaporization device 120 also includes a pipe 3a connecting a hydrogen tank (not shown) in which liquid hydrogen is stored and the hydrogen pump 70, a pipe 3b connecting the hydrogen pump 70 and the nitrogen condenser 40, a pipe 3c connecting the nitrogen condenser 40 and the heater 80, and a pipe 3d connecting the heater 80 and equipment (not shown) that uses gaseous hydrogen.

[0023] The hydrogen pump 70 is, for example, a vortex pump and is configured to continuously pump liquid hydrogen through the pipe 3a. The nitrogen condenser 40 performs heat exchange between gaseous nitrogen (high temperature) and liquid hydrogen (low temperature), so the hydrogen evaporates and becomes gaseous. Further, the gaseous hydrogen is heated by the heater 80 until it reaches room temperature, which is the operating temperature range. Also, in the hydrogen vaporization device 120, the hydrogen exchanges heat with nitrogen in the nitrogen condenser 40 and becomes gaseous, flowing through the pipe 3c.

[0024] (Operation of nitrogen refrigerant power generation system) Here, with reference to Figure 2, the operation of the nitrogen refrigerant power generation device 100 will be explained in detail. As shown in Figure 2, in the pH diagram of nitrogen as a refrigerant circulating within the nitrogen refrigerant power generation device 100, the vertical axis represents absolute pressure [MPa] and the horizontal axis represents enthalpy [kJ / kg]. Also, the letters A, B, C, and D in Figure 2 correspond to the letters A, B, C, and D displayed in the nitrogen refrigerant power generation device 100 in Figure 1. For example, point B in Figure 2 shows the relationship between the pressure and enthalpy of nitrogen in piping 1b in Figure 1. The nitrogen as a refrigerant in the nitrogen refrigerant power generation device 100 is liquid in the region to the left of the saturated liquid line and superheated vapor in the region to the right of the saturated vapor line.

[0025] First, let's explain the state of nitrogen at point A in Figure 2, that is, in the piping 1a between the nitrogen tank 50 and the nitrogen pump 10 in Figure 1. Note that the state of nitrogen at point A is the same as the state of nitrogen in the piping 1e between the nitrogen condenser 40 and the nitrogen tank 50. Here, nitrogen has a boiling point of approximately -196°C and a melting point (freezing point) of approximately -210°C at atmospheric pressure. The nitrogen in piping 1a is kept under pressurized conditions of 0.3 MPa absolute pressure to prevent cavitation. Due to the pressurization, the nitrogen in piping 1a exists in a state that does not saturate (liquid state) even at a temperature of approximately -190°C, which is higher than its boiling point at atmospheric pressure. Subsequently, the liquid nitrogen in piping 1a is compressed and pumped by the nitrogen pump 10.

[0026] Next, we will explain the state of nitrogen in point B in Figure 2, that is, in piping 1b between the nitrogen pump 10 and the nitrogen evaporator 20 in Figure 1. The liquid nitrogen in piping 1b is compressed by the nitrogen pump 10 and maintained under a pressurized state of 0.6 MPa absolute pressure, which is higher than the pressure in piping 1a. Since there is no heat transfer (insulation) and no temperature change when the liquid nitrogen is transferred from piping 1a to piping 1b, the enthalpy in the pH diagram of Figure 2 remains approximately constant during the transition process from point A to point B. Subsequently, the nitrogen in piping 1b is transported to piping 1c via the nitrogen evaporator 20.

[0027] Next, we will explain the state of nitrogen in pipe 1c, which is point C in Figure 2, that is, the state of nitrogen between the nitrogen evaporator 20 and the nitrogen power generation unit 30 in Figure 1. The nitrogen in pipe 1c undergoes heat exchange with seawater transported from the seawater circulation device 110 by the nitrogen evaporator 20, changing from a liquid state to a gaseous state. That is, the liquid nitrogen flowing in pipe 1b receives thermal energy from the nitrogen evaporator 20, is heated from -190°C to -156°C, becomes a gaseous state, and is discharged into pipe 1c. At this time, the pressure of the nitrogen drops slightly due to pressure loss in the nitrogen evaporator 20, but remains approximately constant. Therefore, the gaseous nitrogen in pipe 1c (the state of nitrogen at point C in Figure 2) has a higher enthalpy than the liquid nitrogen in pipe 1b (the state of nitrogen at point B in Figure 2). Subsequently, the nitrogen in pipe 1c is transported into pipe 1d via the nitrogen power generation unit 30.

[0028] Next, we will explain the state of nitrogen in pipe 1d, which is point D in Figure 2, that is, the state of nitrogen between the nitrogen power generation unit 30 and the nitrogen condenser 40 in Figure 1. The gaseous nitrogen in pipe 1d undergoes adiabatic expansion by the nitrogen power generation unit 30, transitioning to a lower pressure and lower temperature state compared to the gaseous nitrogen in pipe 1c. Specifically, the gaseous nitrogen in pipe 1c is expanded by the turbine 30a, causing its temperature to drop from -156°C to -178°C and its absolute pressure to decrease from 0.6 MPa to 0.3 MPa. Therefore, the gaseous nitrogen in pipe 1d (the state of nitrogen at point D in Figure 2) has a lower enthalpy than the liquid nitrogen in pipe 1c (the state of nitrogen at point C in Figure 2). Subsequently, the nitrogen in pipe 1d is transported to pipe 1e via the nitrogen condenser 40.

[0029] Next, we will explain the state of nitrogen in pipe 1e, which is point E in Figure 2, that is, the state of nitrogen between the nitrogen condenser 40 and the nitrogen tank 50 in Figure 1. The gaseous nitrogen in pipe 1e undergoes heat exchange with hydrogen transported from the hydrogen vaporizer 120 by the nitrogen condenser 40. That is, the liquid nitrogen flowing in pipe 1d has its thermal energy removed by the nitrogen condenser 40, and its temperature drops from -178°C to -190°C, causing it to become liquid and be discharged into pipe 1e. At this time, the pressure of the nitrogen drops slightly due to pressure loss in the nitrogen condenser 40, but remains approximately constant. Therefore, the gaseous nitrogen in pipe 1e (the state of nitrogen at point E in Figure 2) has a lower enthalpy than the liquid nitrogen in pipe 1d (the state of nitrogen at point D in Figure 2). Subsequently, the nitrogen in pipe 1e is transported into pipe 1a via the nitrogen tank 50. Note that there is no change in the state of nitrogen before or after the nitrogen tank 50.

[0030] [Second Embodiment] Next, with reference to Figure 3, the configuration of the power generation system 300 according to the second embodiment of the present invention will be described. In the second embodiment, the power generation system is configured to operate by utilizing the cold energy generated from nitrogen used as a refrigerant in the power generation system 200, which is operated by the power generation system 200 of the first embodiment.

[0031] (Configuration of the power generation system) In this second embodiment, the power generation system 300 further includes a propane refrigerant power generation device 101 in addition to the configuration of the first embodiment, and the seawater circulation device 110 is configured to be connected to the propane refrigerant power generation device 101 rather than the nitrogen refrigerant power generation device 100. Points common to the first embodiment in the second embodiment will not be explained. Note that the propane refrigerant power generation device 101 is an example of the "second power generation device" in the claims.

[0032] (Configuration of a nitrogen refrigerant power generation system) The propane refrigerant power generation device 101 comprises a propane pump 11, a propane evaporator 21, a propane power generation unit 31, a propane condenser 41, and a propane tank 51. Here, the propane condenser 41 of the propane refrigerant power generation device 101 has a single configuration common to the nitrogen evaporator 20 of the nitrogen refrigerant power generation device 100. The propane pump 11 is an example of the "second refrigerant pump" in the claims, the propane evaporator 21 is an example of the "second refrigerant evaporator" in the claims, and the propane power generation unit 31 is an example of the "second power generation unit" in the claims.

[0033] Furthermore, the propane tank 51 and the propane pump 11 are connected by piping 4a. The propane pump 11 and the propane evaporator 21 are connected by piping 4b. The propane evaporator 21 and the propane power generation unit 31 are connected by piping 4c. The propane power generation unit 31 and the propane condenser 41 (nitrogen evaporator 20) are connected by piping 4d. The propane condenser 41 (nitrogen evaporator 20) and the propane tank 51 are connected by piping 4e. Inside piping 4a to 4e, liquid or gaseous propane flows as a refrigerant. In addition, insulating material (not shown) is placed outside piping 4a to 4e.

[0034] The propane pump 11 is used as a compressor and is configured to compress the liquid propane flowing through piping 4a and to supply it to the propane evaporator 21 via piping 4b. The propane pump 11 is also controlled by an inverter (not shown). This allows the propane pump 11 to adjust the flow rate of liquid propane discharged from it.

[0035] The propane evaporator 21 is configured to use seawater introduced by the seawater circulation device 110 to evaporate high-pressure liquid propane in pipe 4b, which has been pumped by the propane pump 11, and send the evaporated propane to pipe 4c. In other words, the propane evaporator 21 facilitates heat exchange between seawater (high temperature) and liquid propane (low temperature). The propane evaporator 21 is, for example, a shell-and-tube heat exchanger.

[0036] The propane power generation unit 31 includes a turbine 31a and a generator 31b, and is configured to generate alternating current power. The turbine 31a is configured to rotate a turbine (not shown) included in the generator 31b by using the energy released from the gaseous propane, which is expanded to a low-pressure state by the high-pressure gaseous propane flowing through the pipe 4c. The generator 31b is configured to convert the rotational energy generated by the rotation of the turbine (not shown) into electrical energy and extract (output) it as alternating current power.

[0037] The propane condenser 41 is configured to use the cold energy of nitrogen, which is the refrigerant of the nitrogen refrigerant power generation system 100, to condense the gaseous propane in the pipe 4d that has passed through the turbine 31a, and send it to the pipe 4e. In other words, the propane condenser 41 performs heat exchange between gaseous propane (high temperature) and liquid nitrogen (low temperature). The propane condenser 41 is, for example, a shell-and-tube heat exchanger.

[0038] Here, propane has a melting point (freezing point) of approximately -188°C and a boiling point of approximately -42°C at atmospheric pressure, which is higher than the boiling point of nitrogen (-196°C). In this second embodiment, the flow rate of propane through the propane condenser 41 is greater than the amount of nitrogen flowing through the propane condenser 41. As a result, although the freezing point of propane flowing through the propane condenser 41 is around -188°C, even if heat exchange occurs with nitrogen at around -190°C, it flows in a liquid state without freezing.

[0039] The propane tank 51 is configured to temporarily store liquid propane discharged from the propane condenser 41. As a result, the propane tank 51 functions as an accumulator, for example, to bring the pressure inside the propane refrigerant power generation device 101 closer to a constant pressure even when fluctuations occur in the propane power generation unit 31, which acts as a load.

[0040] In this second embodiment, the propane condenser 41 (nitrogen evaporator 20) of the propane refrigerant power generation device 101 vaporizes the nitrogen used as refrigerant in the nitrogen refrigerant power generation device 100, and utilizes the cold energy generated when vaporizing the nitrogen to condense the propane used as refrigerant in the propane refrigerant power generation device 101. Other aspects are the same as in the first embodiment.

[0041] [Differentiation] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0042] For example, the power generation system 200 or the power generation system 300 may be configured to include a neon power generation device that uses neon as a refrigerant instead of the nitrogen refrigerant power generation device 100. Furthermore, for example, the power generation system 200 or the power generation system 300 may connect an atmospheric circulation device to the nitrogen evaporator 20 of the nitrogen refrigerant power generation device 100, or to the propane evaporator 21 of the propane refrigerant power generation device 101, instead of the seawater circulation device 110. In this case, since the atmosphere used is used as is without heating or cooling, the temperature of the atmosphere will be higher than that of liquid nitrogen and propane. Furthermore, for example, the power generation system 200 may be configured to include a steam turbine driven by neon gas instead of nitrogen. Furthermore, for example, a third power generation device using a refrigerant with an even higher boiling point than propane, which is used as the refrigerant in the propane refrigerant power generation device 101, may be connected to the propane refrigerant power generation device 101 included in the power generation system 300. In addition, the power generation system 300 may have a neon power generation device using neon, which has a lower boiling point than nitrogen, as the refrigerant, connected to the nitrogen condenser 40 side of the nitrogen refrigerant power generation device 100. Furthermore, for example, the nitrogen evaporator 20 and the propane condenser 41 may not be part of a common facility but may be provided separately. In that case, it is advisable to provide a configuration that transfers the cold energy of the nitrogen passing through the nitrogen evaporator 20 to the propane condenser 41. Furthermore, for example, the power generation system 300 may be configured to include a power generation device that uses a refrigerant having a higher boiling point than nitrogen (a fluorine-based refrigerant), such as a fluorine-based refrigerant power generation device that uses a fluorine-based refrigerant as the refrigerant instead of the propane refrigerant power generation device 101. Furthermore, for example, vacuum-insulated piping may be used for pipes 1a-1e, 3a-3c, and 4a-4e, regardless of whether or not external insulation is present. Furthermore, for example, the nitrogen refrigerant power generation device 100 may be configured to operate at temperatures and pressures other than those indicated in the pH diagram of the steam cycle described in Figure 2. Furthermore, the nitrogen evaporator 20, nitrogen condenser 40, and propane evaporator 21 may be replaced with any type of heat exchanger capable of exchanging heat for a fluid, including not only shell-and-tube heat exchangers, but also fan coil unit heat exchangers, brazed plate heat exchangers, gasket plate heat exchangers, immersion heat exchangers, or jacketed tank heat exchangers. Furthermore, the nitrogen pump 10, propane pump 11, seawater pump 60, and hydrogen pump 70 can be any type of pump capable of continuous fluid transport, including centrifugal pumps such as diffuser pumps, axial flow pumps, and mixed flow pumps, in addition to vortex pumps. Furthermore, the control of the liquid flow rate within various steam cycles is not limited to the nitrogen pump 10 and propane pump 11 controlled by an inverter; for example, it may also be controlled by adding a bypass flow path. Furthermore, instead of seawater, air may be used to evaporate the various refrigerants in the nitrogen evaporator 20 or propane evaporator 21. In this case, the nitrogen evaporator 20 or propane evaporator 21 may include a fan (not shown) and be configured to promote the evaporation of the liquid refrigerant by transferring the thermal energy of the air surrounding the nitrogen evaporator 20 or propane evaporator 21 to the liquid refrigerant using the fan. Furthermore, the power generation systems 200 and 300 may use a hydrogen heat exchanger that raises the temperature of hydrogen by performing heat exchange between hydrogen and a refrigerant, rather than a hydrogen vaporizer 120. In this case, power generation becomes possible using the cold energy generated when the temperature of hydrogen is raised, rather than the cold energy generated by the evaporation of hydrogen.

[0043] [Aspect] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0044] (Item 1) A first refrigerant pump that delivers the first refrigerant in liquid form, A first heat exchanger that evaporates the first refrigerant in a liquid state and performs heat exchange, A first power generation unit that generates electricity by being driven by the first refrigerant in a gaseous state, A first power generation device including a second heat exchanger that condenses the first refrigerant, which is in a gaseous state having a boiling point higher than the boiling point of hydrogen, and performs heat exchange with it. The second heat exchanger is equipped with a hydrogen supply unit that supplies the hydrogen in liquid state, The first power generation unit is configured to generate electricity within a steam cycle that uses the cold energy generated when the hydrogen evaporates due to heat exchange between the liquid hydrogen and the gaseous first refrigerant by the second heat exchanger. The first power generation unit generates electricity within a steam cycle that utilizes the cold energy generated by the change in hydrogen's state and temperature through heat exchange between liquid hydrogen and gaseous first refrigerant via a second heat exchanger. This configuration allows the steam cycle to utilize the cold energy generated by the change in hydrogen's state and temperature. As a result, it is possible to generate electrical energy (electricity) using the cold energy generated by the change in hydrogen's state and temperature. Consequently, a system can be provided that can recover at least one of the energy consumed up to the point of hydrogen vaporization by using the cold energy generated when hydrogen is vaporized. (Item 2) The power generation system according to item 1, wherein the first refrigerant comprises at least one of nitrogen or neon. In this case, since nitrogen and neon each have relatively low freezing points, they are less likely to solidify even when using cold energy generated from a very cold substance like liquid hydrogen, making it easier for a vapor cycle to occur. This allows for power generation using materials suitable for utilizing the cold energy generated by the phase change and temperature change of hydrogen. (Item 3) The power generation system according to item 1, wherein the first heat exchanger is configured to evaporate the first refrigerant in a liquid state by exchanging heat between the atmosphere or seawater and the first refrigerant, thereby using the thermal energy of the atmosphere or seawater. In this case, the first refrigerant can be evaporated using air or seawater, which are virtually inexhaustible resources. Therefore, it becomes unnecessary to use energy-consuming equipment, such as a heating element, for the evaporation of the first refrigerant. (Item 4) The first refrigerant is nitrogen, The power generation system according to item 1, wherein the first power generation device is configured to circulate the nitrogen under pressurized conditions. In this case, electricity can be generated using a steam cycle with nitrogen, which can be easily produced from the atmosphere and is a relatively safe inert gas to use. (Item 5) The power generation system according to item 4, wherein the first power generation device includes a steam turbine driven by gaseous nitrogen. In this case, since a steam turbine driven by gaseous nitrogen is used, the nitrogen in the steam cycle can be expanded when the impeller in the steam turbine is rotated. This allows the expanded first refrigerant to be introduced into the first refrigerant pump, enabling the steam cycle to function properly and generating electricity. (Item 6) A second refrigerant pump that delivers a second refrigerant having a higher boiling point than the first refrigerant, A second refrigerant evaporator for evaporating the second refrigerant in liquid state, The power generation system according to item 1, further comprising: a second power generation unit that expands the second refrigerant in a gaseous state and generates electricity driven by the second refrigerant in a gaseous state, and a second power generation device connected to the first power generation device. In this case, by connecting a second power generation device, which uses a second refrigerant having a higher boiling point than the first refrigerant, to the first power generation device, the second power generation device can generate electricity using the thermal energy of the first refrigerant. Therefore, it is possible to generate a larger amount of electricity more efficiently compared to when the first power generation device generates electricity alone. (Item 7) The first heat exchanger is, As part of the first power generation device, the first refrigerant in liquid state is evaporated, As part of the second power generation device, it is configured to exchange heat between the liquid first refrigerant and the gaseous second refrigerant to evaporate the liquid first refrigerant, and to use the cold energy generated when the liquid first refrigerant is evaporated to condense the gaseous second refrigerant that has passed through the second power generation unit. The power generation system according to item 6, wherein the second power generation unit is configured to generate electricity within a steam cycle using the cold energy generated when the first refrigerant evaporates due to heat exchange between the first refrigerant in a liquid state and the second refrigerant in a gaseous state by the first heat exchanger. In this case, a vapor cycle can be configured that utilizes the cold energy released when the first refrigerant evaporates to condense the second refrigerant. Furthermore, by having the first heat exchanger share the functions of both the evaporator of the first power generation unit and the condenser of the second power generation unit, the complexity of the power generation system combining the first and second power generation units can be suppressed, and the system can be configured in a space-saving manner. (Item 8) The first refrigerant comprises at least one of nitrogen or neon, whose boiling point is higher than that of hydrogen. The power generation system described in item 7, wherein the second refrigerant is propane. In this case, because the second refrigerant is propane, which has a higher boiling point than the first refrigerant, the cold energy released when the first refrigerant evaporates can be used to appropriately change the gaseous propane into a liquid state. (Item 9) A first refrigerant pump that delivers the first refrigerant in liquid form, A first heat exchanger that evaporates the first refrigerant in a liquid state and performs heat exchange, A first power generation unit that generates electricity by being driven by the first refrigerant in a gaseous state, The system comprises a second heat exchanger that condenses the first refrigerant, which is in a gaseous state and has a boiling point higher than that of hydrogen, and performs heat exchange with it. The first power generation unit is configured to generate electricity within a steam cycle that uses cold energy generated by the change in the state and temperature of the hydrogen, which is produced by the heat exchange between the hydrogen and the first refrigerant in a gaseous state via the second heat exchanger. The same technical effects as in item 1 can be obtained in the present invention. [Explanation of Symbols]

[0045] 10. Nitrogen pump (first refrigerant pump) 11. Propane pump (second refrigerant pump) 20. Nitrogen evaporator (first heat exchanger) 21. Propane evaporator (second refrigerant evaporator) 30 Nitrogen Power Generation Section (No. 1 Power Generation Section) 31. Propane Power Generation Department (Second Power Generation Department) 40. Nitrogen condenser (second heat exchanger) 41. Propane condenser (first heat exchanger) 70 Hydrogen pump (hydrogen liquid delivery unit) 100 Nitrogen Refrigerant Power Generation System 101 Propane refrigerant power generation system 200, 300 power generation systems

Claims

1. A first refrigerant pump that delivers the first refrigerant in liquid form, A first heat exchanger that evaporates the first refrigerant in a liquid state and performs heat exchange, A first power generation unit that generates electricity by being driven by the first refrigerant in a gaseous state, A first power generation device including a second heat exchanger that condenses the first refrigerant, which is in a gaseous state having a boiling point higher than the boiling point of hydrogen, and performs heat exchange with it. The second heat exchanger is equipped with a hydrogen supply unit that supplies the hydrogen, The first power generation unit is configured to generate electricity within a steam cycle that uses cold energy generated by a change in the state or temperature of the hydrogen, which is produced by heat exchange between the hydrogen and the first refrigerant in a gaseous state via the second heat exchanger.

2. The power generation system according to claim 1, wherein the first refrigerant comprises at least one of nitrogen or neon.

3. The power generation system according to claim 1, wherein the first heat exchanger is configured to evaporate the first refrigerant in a liquid state by exchanging heat between the atmosphere or seawater and the first refrigerant, thereby using the thermal energy of the atmosphere or seawater.

4. The first refrigerant is nitrogen, The power generation system according to claim 1, wherein the first power generation device is configured to circulate the nitrogen under pressurized conditions.

5. The power generation system according to claim 4, wherein the first power generation device includes a steam turbine driven by gaseous nitrogen.

6. A second refrigerant pump that delivers a second refrigerant having a higher boiling point than the first refrigerant, A second refrigerant evaporator for evaporating the second refrigerant in liquid state, The power generation system according to claim 1, further comprising: a second power generation unit that expands the second refrigerant in a gaseous state and generates electricity driven by the second refrigerant in a gaseous state, and a second power generation device connected to the first power generation device.

7. The first heat exchanger is, As part of the first power generation device, the first refrigerant in liquid state is evaporated, As part of the second power generation device, it is configured to exchange heat between the liquid first refrigerant and the gaseous second refrigerant to evaporate the liquid first refrigerant, and to use the cold energy generated when the liquid first refrigerant is evaporated to condense the gaseous second refrigerant that has passed through the second power generation unit. The power generation system according to claim 6, wherein the second power generation unit is configured to generate electricity within a steam cycle using the cold energy generated when the first refrigerant evaporates due to heat exchange between the first refrigerant in a liquid state and the second refrigerant in a gaseous state by the first heat exchanger.

8. The first refrigerant comprises at least one of nitrogen or neon, whose boiling point is higher than that of hydrogen. The power generation system according to claim 7, wherein the second refrigerant is propane.

9. A first refrigerant pump that delivers the first refrigerant in liquid form, A first heat exchanger that evaporates the first refrigerant in a liquid state and performs heat exchange, A first power generation unit that generates electricity by being driven by the first refrigerant in a gaseous state, The system comprises a second heat exchanger that condenses the first refrigerant, which is in a gaseous state and has a boiling point higher than that of hydrogen, and performs heat exchange with it. The first power generation unit is configured to generate electricity within a steam cycle that uses cold energy generated by the change in the state and temperature of the hydrogen, which is produced by the heat exchange between the hydrogen and the first refrigerant in a gaseous state via the second heat exchanger.

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