Supply system for an energy converter

Abstract

The proposed invention relates to a supply system (100) for supplying operating medium to a consumer (201), wherein the supply system (100) includes a working cylinder (107), a compressor cylinder (109), a piston (111), and a heating element (113). Furthermore, the invention relates to an energy conversion system (200) for converting energy.

Description

Technical Field

[0001] The invention relates to a supply system for supplying operating media to a consumer, and an energy conversion system for converting energy according to the appended claims. Background Technology

[0002] To minimize climate change, solutions to avoid greenhouse gas emissions are being sought in many sectors. One promising solution is to replace fossil fuels with hydrogen.

[0003] Another way to avoid greenhouse gas emissions is to use synthetic fuels, which can also be stored at low temperatures.

[0004] On the one hand, hydrogen seems to be an almost ideal alternative in many respects because its use not only eliminates greenhouse gas emissions but also other pollutant emissions.

[0005] On the other hand, hydrogen storage remains a problem because hydrogen requires a very large storage volume due to its low density, and the flammability of its mixture with air must be considered when using hydrogen.

[0006] One possibility for solving these problems is to store hydrogen as an extremely cold fluid. This would involve either using low pressure and extremely low temperature (e.g., 4-6 bar, about 25 K) or using high pressure at slightly higher temperatures (e.g., 350 bar, about 70 K).

[0007] To prevent unwanted evaporation and the resulting need to release hydrogen, the storage container or tank used must not only be sealed to the hydrogen but also be highly insulated. However, this creates a problem: the pressure inside the tank drops when hydrogen is removed.

[0008] Another problem is providing the necessary inlet pressure for the consumer (e.g., internal combustion engine) because, depending on the chosen storage strategy, the hydrogen reserves in the tank are at a pressure lower than the inlet pressure required by the consumer.

[0009] To best utilize the storage capacity of each tank, it is necessary to artificially increase the pressure inside or outside the tank. However, continuous operation of the pumps under cryogenic conditions remains a challenge. Summary of the Invention

[0010] Within the framework of the proposed invention, a supply system and an energy conversion system are proposed. Other features and details of the invention are derived from the corresponding dependent claims, description, and drawings. Herein, the features and details described in conjunction with the supply system according to the invention naturally also apply to the energy conversion system according to the invention, and vice versa, so that the disclosures regarding the various aspects of the invention are always mutually referential or mutually referable.

[0011] The proposed invention is particularly useful for providing the feasibility of safely supplying a consumer (e.g., an energy converter) with an operating medium (e.g., hydrogen).

[0012] Therefore, according to the first aspect of the proposed invention, a supply system for supplying operating medium to a consumer is proposed.

[0013] The proposed supply system includes a working cylinder, a compressor cylinder, a piston, and a thermal element. The working cylinder is fluidly connected to the thermal element at its inlet side and to an energy converter of the operating medium flowing out of the working cylinder at its outlet side. The compressor cylinder is fluidly connected to a liquid storage tank for storing the operating medium through a first opening and to the thermal element through a second opening.

[0014] Furthermore, the piston is movably supported between the bottom dead center and top dead center positions in the working cylinder and the compressor cylinder, and has a working area in the working cylinder that is larger than the compression area of ​​the piston in the compressor cylinder, such that when the operating medium heated by the thermal element expands in the working cylinder, the piston moves in the compressor cylinder and compresses the operating medium located in the supply system via pneumatic transmission.

[0015] In this context, pneumatic transmission should be understood as the increase in pressure caused by the different sizes of the piston's surface area when the piston moves within a volume, causing the piston to transfer the force provided on its working area for moving the piston to a smaller compressor area, thereby increasing the force provided by the compressor area relative to the force provided on the working area.

[0016] The proposed supply system is based on a single piston capable of moving within two fluid-separated chambers: a working cylinder and a compressor cylinder. Accordingly, movement of the piston portion arranged in the working cylinder causes subsequent movement of the piston portion arranged in the compressor cylinder. The piston then transfers mechanical energy from the working cylinder to the compressor cylinder.

[0017] In order to provide a force acting on the piston in the working cylinder to move it between top dead center and bottom dead center, the proposed supply system includes a thermal element (e.g., an evaporator) that heats the operating medium flowing into the working cylinder, causing the operating medium to expand in the working cylinder and thereby causing piston movement.

[0018] The movement of the piston compresses or compacts the operating medium in the compressor cylinder, causing the pressure in the pipeline system to rise as the compressed operating medium is discharged into the supply system.

[0019] The pressure in the piping system is increased by the movement of the piston until it corresponds at least to the pressure of the supply line used to supply the energy converter (e.g., between 50 bar and 70 bar), so that the compressed operating medium flows from the supply system to the energy converter, and the energy converter can operate continuously.

[0020] Since the energy required to move the piston is provided by the heat supplied to the operating medium in the thermal element, it is possible to forgo supplying higher-value energy (such as for driving an active motor) and maximize the energy efficiency of the corresponding energy conversion system.

[0021] Furthermore, the proposed supply system is compact and robust due to its structural design.

[0022] The supply system may include an elastic element configured to move the piston from the bottom dead center position to the top dead center position.

[0023] After the working process of compressing the operating medium, an elastic element (e.g., an exemplary mechanical spring) returns the piston to its top dead center without actively providing energy or operating the actuator. Accordingly, such an elastic element contributes to the energy efficiency of the corresponding energy conversion system.

[0024] Furthermore, a first control valve can be arranged in a first connecting pipe between the heating element and the working cylinder, and a second control valve can be arranged in a second connecting pipe between the working cylinder and the interface to the consumer. The first control valve and the second control valve can switch between a flow-through state and a closed state, respectively. When the second control valve is in its closed state, the first control valve is in its flow-through state, and when the second control valve is in its flow-through state, the first control valve is in its closed state.

[0025] The flow of the operating medium through the supply system can be set via a first control valve in the first connecting line between the thermal element and the working cylinder, and / or a second control valve in the second connecting line between the working cylinder and the interface to the energy converter. For example, by shutting off the second control valve until a pressure greater than or equal to a predetermined target pressure exists in the supply system, the piston can be moved multiple times to increase the pressure in the supply system.

[0026] Furthermore, the movement of the piston can be controlled by alternately manipulating the two control valves via a first control valve in the first connecting line between the thermal element and the working cylinder and / or a second control valve in the second connecting line between the working cylinder and the interface to the energy converter. This is similar to the inlet and outlet valves at an electrically driven piston compressor or the camshaft control device of a reciprocating piston engine.

[0027] In particular, the second control valve can prevent the operating medium from flowing back from the pipeline system of the energy converter to the supply system.

[0028] Furthermore, the proposed supply system configuration can be configured without a separate outlet valve, and the pressure reducer can take over the function of the outlet valve.

[0029] In addition, pressure relief openings can be configured on the working cylinder and the compressor cylinder respectively, the pressure relief openings being configured to discharge fluid from the supply system.

[0030] To prevent overpressure, i.e. pressure exceeding a predetermined maximum pressure, a pressure relief opening can be provided, which is coupled to the ambient fluid, for example by means of a pressure valve (i.e., a valve that opens from a predetermined adjustment pressure).

[0031] In addition, leaks that occur on the piston can be discharged using a pressure relief port.

[0032] Furthermore, the working cylinder can be configured to include a first inlet opening and a second inlet opening on the inlet side, and a first outlet opening and a second outlet opening on the outlet side. A first control valve is arranged in the first connecting pipe between the heating element and the working cylinder, and a second control valve is arranged in the second connecting pipe between the working cylinder and the connecting pipe to the energy converter. The first control valve is a three-way valve, which is coupled to the heating element in a switchable manner through the first connecting pipe, to the first inlet opening of the working cylinder in a switchable manner through the first inlet pipe, and to the second inlet opening of the working cylinder in a switchable manner through the second inlet pipe. The first inlet opening enters the working cylinder above the top dead center of the piston within the working cylinder, and the second inlet opening is located at the bottom dead center of the piston within the working cylinder. The lower part of the valve leads into the working cylinder. The second control valve is a three-way valve, which is coupled to the energy converter in a switchable manner through a connecting pipe. It is also coupled to the first outlet opening of the working cylinder in a switchable manner through a first outlet pipe and to the second outlet opening of the working cylinder in a switchable manner through a second outlet pipe. The first outlet opening leads into the working cylinder above the top dead center of the piston in the working cylinder, and the second outlet opening leads into the working cylinder below the bottom dead center of the piston in the working cylinder. The first and second control valves are configured to switch synchronously and in opposite directions, such that the connecting pipe can only be connected to the first inlet opening when the outlet pipe is connected to the second outlet opening, and the connecting pipe can only be connected to the second inlet opening when the outlet pipe is connected to the first outlet opening.

[0033] Furthermore, the compressor cylinder may be configured to include a first inlet opening and a second inlet opening, wherein the first inlet opening is connected to the compressor cylinder above the second inlet opening along the direction of piston movement toward its top dead center, and wherein the compressor cylinder includes a first outlet opening and a second outlet opening, wherein the first outlet opening is led out of the compressor cylinder above the second outlet opening along the direction of piston movement toward its top dead center.

[0034] By using multiple inlet and outlet openings in the working cylinder or compressor cylinder, the piston can perform compression work both when moving downwards (i.e., from top dead center to bottom dead center) and when moving upwards (i.e., from its bottom dead center to top dead center). Furthermore, the elastic element used to move the piston back to its top dead center position can be omitted.

[0035] Additionally, the second control valve may include an electronic valve control device configured to control the second control valve based on the pressure present in the connecting pipeline, thereby setting the pressure in the connecting pipeline.

[0036] The electronic valve control device can be implemented, for example, in a computing unit, and process the pressure values ​​existing in the connecting pipeline, obtained from pressure sensors or by means of mathematical models. Accordingly, for example, when the pressure in the connecting pipeline is greater than or equal to the pressure in the pipeline system of the energy converter supplied by the supply system, the electronic valve control device can open a second control valve to prevent the operating medium from flowing back from the pipeline system of the energy converter to the supply system.

[0037] Additionally, the thermal element can be thermally coupled to the energy converter, which in turn is thermally coupled to the supply system, so as to heat the operating medium flowing through the supply system by the heat dissipated by the energy converter.

[0038] In general, thermal elements can be thermally coupled to or include any technically possible heat source. Thermal coupling with the energy converter to utilize the waste heat of the energy converter and accordingly cool the energy converter has proven to be particularly energy-efficient, as it also reduces the energy requirements for cooling the energy converter.

[0039] In addition, the supply system may be configured to include multiple storage tanks, which are configured to store the operating medium under cryogenic conditions.

[0040] The storage tanks, particularly liquid storage tanks for storing liquid operating media, especially hydrogen, have typical operating pressures, for example, between 4 bar and 6 bar and between 20 Kelvin and 30 Kelvin. Alternatively, the storage tanks may be pressure tanks for storing operating media, for example, with pressures between 300 bar and 400 bar and temperatures between 70 Kelvin and 80 Kelvin.

[0041] What proves particularly advantageous when using the proposed supply system with a liquid operating medium is that the piston acts directly on the liquid operating medium to compress it. This results in a particularly rapid pressure rise in the supply system. Furthermore, the compression of the liquid medium achieves exceptionally high compressor efficiency.

[0042] According to the second aspect, the proposed invention relates to an energy conversion system for converting energy.

[0043] The proposed energy conversion system includes an energy converter and a possible configuration of the proposed supply system.

[0044] It can be configured that the energy converter is a fuel cell system or an internal combustion engine, especially a hydrogen engine, that is, an internal combustion engine that runs on hydrogen as fuel, such as a reciprocating piston engine or a rotary piston engine.

[0045] The advantages described in detail in the supply system for supplying operating medium to a consumer according to the first aspect of the invention are also applicable to the energy conversion system for converting energy according to the second aspect of the invention. Attached Figure Description

[0046] Other advantages, features, and details of the invention are derived from the following description, in which embodiments of the invention are described in detail with reference to the accompanying drawings. Herein, the features mentioned in the claims and the description may be essential to the invention individually or in any combination.

[0047] It shows: Figure 1 : Schematic diagrams of a possible configuration of the proposed energy conversion system and a possible configuration of the proposed supply system. Figure 2 :according to Figure 1 A supply system with another possible configuration of the proposed supply system. Figure 3 :according to Figure 2 A supply system with electronic valve control devices. Detailed Implementation

[0048] Figure 1 The diagram shows an energy conversion system 200 having an energy converter 201 and a supply system 100.

[0049] The supply system 100 is connected to the storage tank 103 for storing the operating medium via the storage tank line 101, and to the energy converter 201 (shown here exemplary in the form of a conventional piston internal combustion engine) via the supply line 105.

[0050] The supply system 100 includes a working cylinder 107, a compressor cylinder 109, a piston 111, and a thermal element 113.

[0051] The working cylinder 107 is fluidly connected to the heating element 113 on the inlet side and connected to the energy converter 201 on the outlet side.

[0052] Compressor cylinder 109 is fluidly connected to storage tank 103 on the inlet side and to thermal element 113 on the outlet side. Shut-off valves 115 and 117 prevent backflow from compressor cylinder 109 to storage tank 103 or from thermal element 113 to compressor cylinder 109.

[0053] As in Figure 1 As shown, piston 111 is movably supported in working cylinder 107 and compressor cylinder 109 between bottom dead center and top dead center positions.

[0054] The piston 111 has a working area 119 in the working cylinder 107, which is larger than the compression area 121 formed by the piston 111 in the compressor cylinder 109. Correspondingly, the expansion of the operating medium heated by the thermal element in the working cylinder 107 causes the piston 111 to move from the compressor cylinder 109... Figure 1 The motion from the top dead center position to the bottom dead center position is shown as indicated by arrow 123.

[0055] To reset piston 111 to the top dead center position, piston 111 is connected to elastic element 125, which is exemplarily shown here in the form of a mechanical spring.

[0056] The movement of piston 111 compresses the operating medium located in compressor cylinder 109 and delivers it to energy converter 201 via supply line 127, which optionally extends through working cylinder 107.

[0057] A first control valve 129 is provided to control the flow of the operating medium into the working cylinder 107. A second control valve 131 is provided to prevent the operating medium from flowing back from the energy converter 201 into the supply system 100. The first control valve 129 and the second control valve 131 are switchable valves, particularly proportional valves. In principle, the implementation of control valve 131 can also be conceived as a simple check valve. Alternatively, a pressure regulator 135 can be used to prevent backflow.

[0058] The leakage can be discharged along the longitudinal sides of the two pistons through the pressure relief line 133.

[0059] Alternatively, overpressure protection can be integrated into the areas between control valves 115 and 129, and between control valves 129 and 131. This is because a closed space is created by the shut-off valve 117 and control valve 129, preventing pressure rise from escaping. The same applies to the space between control valves 129 and 131. Accordingly, overpressure protection can be achieved using overpressure valves (not shown) in these two areas.

[0060] Alternatively, control valve 129 can be configured as a normally open valve when de-energized. In this case, the two closed areas are interconnected when the system is shut down, making a single overpressure valve sufficient to provide protection.

[0061] Alternatively, control valve 129 can be configured such that it has a "power-off closing" action direction, but can be reversed by a sufficiently high pressure gradient. However, in that case, the pressure threshold for "reverse opening" must be chosen high to prevent backflow during normal operation.

[0062] In addition, a pressure reducer 135 is provided in the supply line 105 to the energy converter 201 to prevent the energy converter 201 from being subjected to overpressure load.

[0063] exist Figure 2 In the process, the working cylinder 107 is connected to the heat element 113 on the inlet side through the first inlet pipe 134, the second inlet pipe 137, and the first control valve 129, and on the outlet side through the first outlet pipe 139, the second outlet pipe 141, and the second control valve 131 to the energy converter 201.

[0064] The first control valve 129 and the second control valve 131 are configured to switch synchronously and in opposite directions, such that flow is released according to arrows 143 and 145 or according to arrows 147 and 149, so as to supply the piston 111 with the operating medium heated by the thermal element 113 both when the piston 111 moves from its bottom dead center to its top dead center and when it moves from its top dead center to its bottom dead center.

[0065] Accordingly, piston 111 performs pneumatic work in two directions of motion to compress the operating medium located in compressor cylinder 109. In other words, the first control valve 129 and the second control valve 131 can be switched for the working stroke of working cylinder 107.

[0066] exist Figure 3 In China, according to Figure 2 The pressure reducer 135 of the supply system 100 has been replaced with an electronic valve control device 151 and a pressure sensor 153, which measures the supply pressure at the inlet of the energy converter. The valve control device 151 is used to compare the actual pressure measured by the pressure sensor 153 with a set value and then to perform tactile control on the two control valves 129 and 131 so that the desired target pressure is supplied to the energy converter 201.

[0067] Meanwhile, valve control device 151 is used to prevent overpressure from being supplied to energy converter 201 by closing the second control valve 131 when the pressure exceeds the allowable upper limit.

Claims

1. A supply system (100) for supplying operating medium to a consumer (201). in, The supply system (100) includes: - Working cylinder (107). - Compressor cylinder (109). - Piston (111). - Thermal element (113) The working cylinder (107) can be fluidly connected to the heating element (113) at the inlet side and can be connected to the energy converter (201) at the outlet side. The compressor cylinder (109) is fluidly connected to a storage tank (103) for storing the operating medium through a first opening, and fluidly connected to the heat element (113) through a second opening. The piston (111) is movably supported in the working cylinder (107) and the compressor cylinder (109) between the bottom dead center position and the top dead center position. The piston (111) has a working area (119) in the working cylinder (107) that is larger than the compression area (121) of the piston (111) in the compressor cylinder (109), such that when the operating medium heated by the heat element (113) expands into the working cylinder (107), the piston (111) moves and compresses the operating medium located in the supply system (100) by pneumatic transmission.

2. The supply system (100) according to claim 1. Its features are, The supply system (100) includes an elastic element (125) configured to move the piston (111) from the bottom dead center position to the top dead center position.

3. The supply system (100) according to claim 1 or 2. Its features are, A first control valve (129) is arranged in a first connecting pipe (127) between the heating element (113) and the working cylinder (107), and a second control valve (131) is arranged in a second connecting pipe between the working cylinder (107) and the interface to the energy converter (201). The first control valve (129) and the second control valve (131) are respectively switchable between a flow-through state and a closed state, and... When the second control valve (131) is in its closed position, the first control valve (129) is in its open position, and when the second control valve (131) is in its open position, the first control valve (129) is in its closed position.

4. The supply system (100) according to any one of the preceding claims. Its features are, Pressure relief openings are respectively constructed on the working cylinder (107) and the compressor cylinder (109), and the pressure relief openings are configured to discharge fluid from the supply system (100).

5. The supply system (100) according to claim 1 or 2. Its features are, The working cylinder (107) includes a first inlet opening and a second inlet opening on the inlet side, and a first outlet opening and a second outlet opening on the outlet side. A first control valve (129) is arranged in a first connecting pipe (127) between the heating element (113) and the working cylinder (107), and a second control valve (131) is arranged in a second connecting pipe between the working cylinder (107) and the connecting pipe to the energy converter (201). The first control valve (129) is a three-way valve. The three-way valve is coupled to the thermal element (113) in a switchable manner via the first connecting pipe (105), to the first inlet opening of the working cylinder (107) in a switchable manner via the first inlet pipe (135), and to the second inlet opening of the working cylinder (107) in a switchable manner via the second inlet pipe (137). The first inlet opening connects to the working cylinder (107) above the top dead center of the piston (111) within the working cylinder, and the second inlet opening connects to the working cylinder (107) below the bottom dead center of the piston (111) within the working cylinder. The second control valve (131) is a three-way valve, which is coupled to the energy converter (201) in a switchable manner via a connecting pipe, coupled to the first outlet opening of the working cylinder (107) in a switchable manner via a first outlet pipe (139), and coupled to the second outlet opening of the working cylinder (107) in a switchable manner via a second outlet pipe (141). The first outlet opening is located above the top dead center of the piston (111) within the working cylinder, leading into the working cylinder (107). The second outlet opening is located below the bottom dead center of the piston (111) within the working cylinder, also leading into the working cylinder (107). The first control valve (129) and the second control valve (131) are configured to switch synchronously and in reverse, such that the connecting pipe can only be connected to the first inlet opening when the outlet pipe is connected to the second outlet opening, and the connecting pipe can only be connected to the second inlet opening when the outlet pipe is connected to the first outlet opening.

6. The supply system (100) according to claim 5. Its features are, The compressor cylinder (109) includes a first inlet opening and a second inlet opening. The first inlet opening enters the compressor cylinder (109) above the top dead center along the direction of movement of the piston (111), and the second inlet opening enters the compressor cylinder (109) below the bottom dead center. The compressor cylinder (109) includes a first outlet opening and a second outlet opening. The first outlet opening enters the compressor cylinder (109) above the top dead center along the movement direction of the piston (111), and the second outlet opening enters the compressor cylinder (109) below the bottom dead center.

7. The supply system (100) according to claim 5 or 6. Its features are, The second control valve (131) includes an electronic valve control device (151) configured to control the second control valve (131) based on the pressure present in the connecting line to set the pressure in the connecting line.

8. The supply system (100) according to any one of the preceding claims. Its features are, The thermal element (113) is thermally coupled to the energy converter (201), which is thermally coupled to the supply system (100) so as to heat the operating medium flowing through the supply system (100) by the heat dissipated by the energy converter (201).

9. The supply system (100) according to any one of the preceding claims. Its features are, The supply system (100) includes multiple storage tanks (103) configured to store operating media under cryogenic conditions.

10. An energy conversion system (200) for converting energy, wherein, The energy conversion system (200) includes: - Energy converter (201). - The supply system (100) according to any one of claims 1 to 9.

11. The energy conversion system (200) according to claim 10. Its features are, The energy converter (201) is a fuel cell system or an internal combustion engine.

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