Cryotank system
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- MAGNA ENERGY STORAGE SYSTEMS GESMBH
- Filing Date
- 2022-07-01
- Publication Date
- 2026-07-09
AI Technical Summary
Existing cryotank systems struggle to efficiently bring multiple cryotanks to operating pressure after refueling with minimal energy consumption, particularly when operated in parallel, due to limited vehicle voltage and current availability.
A cryotank system with two cryotanks configured for parallel operation, where only one cryotank is initially heated post-refueling, and the second is heated with a time delay, using a control unit to manage electrical heaters sequentially, ensuring unidirectional flow and partial recycling to maintain pressure without simultaneous heating.
This approach minimizes energy consumption and reduces the time required to achieve sufficient pressure in all tanks, maintaining efficient fuel supply to the consumer by optimizing the heating sequence and flow management between tanks.
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Field of the invention
[0001] The present invention relates to a cryogenic tank system comprising a first cryogenic tank device and a second cryogenic tank device, wherein the first cryogenic tank device comprises a first cryogenic tank and the second cryogenic tank device comprises a second cryogenic tank, in particular each for receiving hydrogen. State of the art
[0002] Cryogenic tank systems comprising a cryogenic tank for storing hydrogen are known and are used particularly as mobile cryogenic tank systems, for example, in motor vehicles. Each cryogenic tank can comprise an inner container and an outer casing, with an insulating vacuum chamber being provided between the inner container and the outer casing.
[0003] Cryogenic tank systems can also comprise multiple, for example, two, cryogenic tanks for storing a larger amount of hydrogen. The two or more cryogenic tanks can be operated in parallel, allowing fuel to be supplied to a consumer from both cryogenic tanks.
[0004] To regulate the pressure in a cryogenic tank, especially during or after the removal of hydrogen from the cryogenic tank, pressure control devices can be provided, for example, an electric heater in the cryogenic tank or a recirculation line through which extracted and heated hydrogen is partially returned to a heat exchanger in the cryogenic tank to increase the temperature and thus the pressure in the cryogenic tank. Partial recycling enables heat to be coupled into the cryogenic tank and thus a pressure buildup through evaporation of the cryogenic gas.
[0005] After refueling with liquid hydrogen, the addition of subcooled hydrogen can lead to condensation of the gas phase and a resulting pressure drop in a cryogenic tank. For this special case, an additional electric heating element is used to build up a certain internal tank pressure, ensuring sufficient pressure in the tank even within a short period of time after refueling, thus ensuring the ability to withdraw fuel.
[0006] When operating multiple tanks in parallel, all tanks must be brought to the required operating pressure simultaneously to achieve the desired minimum pressure. However, vehicles only have a certain voltage and current available to operate electric heaters to bring the tanks to the required operating pressure immediately after refueling. Summary of the invention
[0007] It is an object of the invention to improve cryogenic tank systems of the type mentioned in this respect and in particular to provide a cryogenic tank system which, despite the use of several cryogenic tanks operated in parallel, can be brought to operating pressure after refueling easily and with low energy consumption.
[0008] The object is achieved by a cryogenic tank system comprising a first cryogenic tank device, a second cryogenic tank device, and a consumer, wherein the first cryogenic tank device comprises a first cryogenic tank and the second cryogenic tank device comprises a second cryogenic tank, in particular each for holding hydrogen, wherein the first cryogenic tank device and the second cryogenic tank device are configured for parallel operation, so that the medium stored in the first and second cryogenic tanks can be supplied to the consumer simultaneously both from the first cryogenic tank via a first withdrawal line and from the second cryogenic tank via a second withdrawal line, wherein the first cryogenic tank device comprises a first electrical heater for heating the medium in the first cryogenic tank, wherein the cryogenic tank system comprises at least one control unit, wherein the first electrical heater can be activated and / or deactivated by the control unit,wherein the control unit is designed, after refueling of the first cryogenic tank and the second cryogenic tank, i.e. at a refueling end time, to heat only the medium of the first cryogenic tank by activating the first electric heater and not to heat the medium of the second cryogenic tank.
[0009] According to the invention, a cryogenic tank system uses at least a first cryogenic tank and a second cryogenic tank, which are configured for parallel operation and can thus both feed the same consumer. The withdrawal of medium from the first and second cryogenic tanks is possible simultaneously.
[0010] According to the invention, after refueling the two cryogenic tanks, when the pressure in both cryogenic tanks drops accordingly, only a single cryogenic tank, namely the first cryogenic tank, is initially heated using an electric heating element to build up a certain internal pressure in the first cryogenic tank. According to the invention, the second cryogenic tank is not heated directly after refueling. Thus, according to the invention, heating of the second cryogenic tank occurs only with a time delay, at a later point in time, so that no additional energy needs to be expended to heat the second cryogenic tank while heating the first cryogenic tank.
[0011] In order to ensure sufficient pressure in the withdrawal line to the consumer and thus the withdrawal capability even in a short period of time after refueling, the cryogenic tank system can be set up in such a way that at least in the period after refueling, when the first cryogenic tank is heated up, the medium from the first withdrawal line cannot flow into the second withdrawal line, so that the consumer can be supplied directly from the first cryogenic tank without pressure loss to the second cryogenic tank.
[0012] Preferably, the first extraction line and the second extraction line are fluidly connected to one another at a connection point and are fluidly connected to the consumer from the connection point via a common consumer line.
[0013] A valve, in particular a check valve, is then preferably arranged in the second withdrawal line, wherein the valve prevents the medium from flowing from the first withdrawal line into the second withdrawal line at least after refueling of the first cryotank and the second cryotank, i.e. at the end of refueling when the first cryotank is heated up.
[0014] The connection from the first cryogenic tank to the second withdrawal line can be permanently closed, so that a unidirectional flow from the second withdrawal line to the consumer is constantly established. The connection to the second cryogenic tank, in particular the check valve, can also be closed only during pressure buildup in the first cryogenic tank. For example, a pressure-dependent valve can be used in the second withdrawal line, so that the pressure-dependent valve opens a flow connection from the first cryogenic tank to the second cryogenic tank when a sufficiently high pressure is present at the first cryogenic tank and thus at the valve. This allows the pressure in the second cryogenic tank to be increased after the first cryogenic tank has heated up.
[0015] Preferably, the first cryogenic tank device comprises a first recycling heater, such that a partial flow of the first extraction line is guided through a first heat exchanger arranged in the first cryogenic tank and, after passing through the first heat exchanger, is returned to the first extraction line. Preferably, the second cryogenic tank device comprises a second recycling heater, such that a partial flow of the second extraction line is guided through a second heat exchanger arranged in the second cryogenic tank and, after passing through the second heat exchanger, is returned to the second extraction line.
[0016] Preferably, the control unit is configured to heat the medium of the second cryotank after a predefined pressure buildup in the first cryotank by heating the medium of the first cryotank by the first electric heater, i.e., at a pressure buildup time. "After a predefined pressure buildup" and thus the "pressure buildup time" can mean that the heating of the second cryotank occurs, for example, when a predefined pressure or a predefined temperature is present in the first cryotank and / or can also be time-controlled, so that the heating of the second cryotank begins after a predefined time of heating the first cryotank.
[0017] For example, heating of the first cryotank can be stopped when heating of the second cryotank starts.
[0018] According to one embodiment of the invention, the control unit can be configured to heat the medium of the second cryogenic tank by activating a second electric heater in the second cryogenic tank at the time the pressure buildup ends. The two electric heaters of the first and second cryogenic tanks, which are operated in parallel, are thus activated sequentially, with a time offset. Upon activation of the second electric heater, the first electric heater is preferably deactivated.
[0019] According to one embodiment, the control unit is designed to heat the medium of the second cryotank at the end of pressure buildup by deactivating the valve, in particular the check valve, which prevents the medium from flowing from the first withdrawal line into the second withdrawal line at least after refueling of the first cryotank and the second cryotank, i.e., at the end of refueling time. Thus, at a later time, after the heating of the first cryotank, a flow connection is established from the first withdrawal line toward the second withdrawal line and thus toward the second cryotank, in order to enable pressure buildup in the second cryotank. The first electrical heater preferably remains activated during the heating of the second cryotank.
[0020] According to one embodiment, the control unit is configured to heat the medium of the second cryogenic tank at the end of the pressure buildup by establishing a flow connection between the first cryogenic tank and the second cryogenic tank, in particular by establishing a flow connection via a boil-off line or via a refueling transfer line, or, as previously mentioned, via the withdrawal lines. The first electrical heater preferably remains activated during the heating of the second cryogenic tank.
[0021] According to one embodiment, the control unit is configured to heat the medium of the second cryogenic tank at the end of the pressure buildup by establishing a flow connection from the first cryogenic tank device to the second recycling heater. The first electrical heater preferably remains activated during the heating of the second cryogenic tank.
[0022] The various options mentioned above for building up pressure in the second cryotank, after building up pressure in the first cryotank, can also be combined as desired. Brief description of the drawings
[0023] The invention is described below by way of example with reference to the drawings. Fig. Figure 1 is a schematic diagram of a cryogenic tank system including a cryogenic tank device with a recycle heater. Fig. 2 is a schematic representation of a cryogenic tank system according to the invention with two cryogenic tank devices. Detailed description of the invention
[0024] Fig. Figure 1 schematically shows a first cryogenic tank device 1 with a first cryogenic tank 4 in which hydrogen (H2) is stored. Liquid hydrogen is located in the lower part of the container (shown with a pattern) and gaseous hydrogen is located above it.
[0025] The first cryogenic tank device 1 comprises a first recycling heater 11, so that thermal energy is fed into the cryogenic fluid in the first cryogenic tank 4 by using a first heat exchanger 12. Two such cryogenic tank devices can be used in a cryogenic tank system according to the invention, as shown in Fig. 2 shown.
[0026] In the first cryogenic tank device 1, pressurized hydrogen gas is withdrawn from the cryogenic tank via a first withdrawal line 6 and heated using a first heat exchanger 15. A first partial mass flow is then recycled through a closed piping system into the first cryogenic tank 4. To enable recycling, a throttle 17 is arranged in the non-recycled second partial mass flow. The valve 18 shown serves to shut off the recycled first partial mass flow of the first recycling heater 11. The recycling of the hydrogen gas leads to its cooling, which is compensated by a second heat exchanger 16. After combining, both partial mass flows are fed to a consumer 3. The partial recycling enables heat to be coupled into the first cryogenic tank 4 and thus a pressure buildup through evaporation of the cryogenic gas.
[0027] Such a pressure build-up system requires an active mass flow in order to be able to return the thermal energy to the fluid by cycling the gas.
[0028] In the Fig. 2 shows a cryogenic tank system according to the invention, which essentially comprises two tank devices as in Fig. 1, namely a first cryogenic tank device 1 with a first cryogenic tank 5 and a second cryogenic tank device 2 with a second cryogenic tank 5. Both cryogenic tank devices 1, 2 also have recycling heaters 11, 13 for partial recycling, as shown in Fig. 1, so that heat coupling into the first cryotank 4 and the second cryotank 5 and thus pressure build-up by evaporation of the cryogenic gas is possible.
[0029] The first cryogenic tank device 1 comprises a first recycling heater 11, wherein a partial flow of the first withdrawal line 6 is guided through a first heat exchanger 12 arranged in the first cryogenic tank 4 and is returned to the first withdrawal line 6 after the first heat exchanger 12, and / or wherein the second cryogenic tank device 2 comprises a second recycling heater 13, wherein a partial flow of the second withdrawal line 7 is guided through a second heat exchanger 14 arranged in the second cryogenic tank 5 and is returned to the second withdrawal line 7 after the second heat exchanger 14.
[0030] The first cryogenic tank device 1 and the second cryogenic tank device 2 are configured for parallel operation, so that the medium stored in the first and second cryogenic tanks 4, 5 can be supplied to the consumer 3 simultaneously from both the first cryogenic tank 4 via a first withdrawal line 6 and the second cryogenic tank 5 via a second withdrawal line 7. The first withdrawal line 6 and the second withdrawal line 7 are fluidly connected to one another at a connection point and, from the connection point, are fluidly connected to the consumer 3 via a common consumer line 9.
[0031] The first cryotank device 1 has a first electric heater 8 for heating the medium in the first cryotank 4, for example a 2kW heater, and a control unit (not shown), wherein the first electric heater 8 can be activated and / or deactivated by the control unit.
[0032] The control unit is designed to heat only the medium of the first cryotank 4 by activating the first electric heater 8 after refueling of the first cryotank 4 and the second cryotank 5, i.e. at the end of refueling time, and not to heat the medium of the second cryotank 5.
[0033] The coupled cryogenic tank systems for mobile applications are therefore operated in such a way that a sequential heating of tanks operated in parallel takes place in order to minimize the heating time and the achievement of operational capability.
[0034] A valve 10, namely a check valve, is arranged in the second withdrawal line 7, wherein the valve 10 prevents the medium from flowing from the first withdrawal line 6 into the second withdrawal line 7 at least after refueling of the first cryotank 4 and the second cryotank 5, i.e. at the end of refueling time, i.e. at least while the first cryotank 4 is being heated up and thus until the end of pressure build-up time, or at least while the second cryotank 5 has not yet reached its operating pressure, or even continuously.
[0035] The heated hydrogen from the first cryogenic tank 4 is then fed directly to the consumer. Backflow of the heated hydrogen into the second cryogenic tank 5 is prevented by measures such as the check valve 10.
[0036] The control unit is designed to heat the medium of the second cryotank 5 after a predefined pressure build-up in the first cryotank 4 by heating the medium of the first cryotank 4 by the first electrical heater 8, i.e. at a pressure build-up time, i.e. when, for example, a certain pressure or a certain temperature is reached in the first cryotank 4 or after a certain time of pressure build-up in the first cryotank 4.
[0037] The heating of the medium in the second cryogenic tank 5 can be achieved, for example, by deactivating or bypassing the check valve 10. The control unit can thus be configured to heat the medium in the second cryogenic tank 5 by deactivating the valve 10, in particular the check valve, at the time the pressure buildup ends. The extraction lines 6, 7 can thus be used to build up pressure in the second cryogenic tank 5 after a defined pressure has been reached in the line.
[0038] The second cryogenic tank device 2 may comprise its own second electrical heater - in the Fig. 2—for example, also a 2kW heater. The control unit can be configured to heat the medium of the second cryogenic tank 5 by activating the second electric heater in the second cryogenic tank 5 at the time the pressure buildup ends.
[0039] After starting the vehicle, the first electric heater 8 can be active, while the second electric heater is inactive. After the operating pressure in the first cryogenic tank 4 is reached, the second cryogenic tank 5 can be heated with the second electric heater, again a 2 kW heater, until operation without the electric heater is possible. The control unit can ensure that the two electric heaters are controlled separately and that both heaters are never in operation simultaneously. This means that the maximum power requirement cannot exceed 2 kW, for example.
[0040] The control unit can be designed to heat the medium of the second cryotank 5 at the end of the pressure build-up time by establishing a flow connection between the first cryotank 4 and the second cryotank 5, in particular by establishing a flow connection via a boil-off line or via a refueling transfer line, i.e. a transfer line that enables joint refueling of the two cryotank devices 1, 2, or - as mentioned above - by establishing a flow connection via the withdrawal lines 6, 7.
[0041] After the vehicle is started, the first electric heater 8 can be active, while the second electric heater is inactive. After the operating pressure in the first cryogenic tank 4 has been reached, the first electric heater 8 can remain active. The second cryogenic tank 5 can be heated up by opening a boil-off line - whereby three additional valves can be used - or by opening the refueling transfer line and transferring the pressure from the first cryogenic tank 4 as the "master tank" to the second cryogenic tank 5 as the "slave tank". To maintain the operating pressure in the master tank, thermal and / or electrical heating can take place in the master tank until the slave tank, the second cryogenic tank 5, has also reached the operating pressure.
[0042] The control unit can also be designed to heat the medium of the second cryotank 5 at the end of the pressure build-up time by establishing a flow connection from the first cryotank device 1 to the second recycling heater 13. List of reference symbols 1 first cryogenic tank device 2 second cryogenic tank device 3 consumers 4 first cryogenic tank 5 second cryotank 6 first extraction line 7 second extraction line 8 first electric heater 9 Consumer line 10 Valve, check valve 11 first recycling heating 12 first heat exchanger 13 second recycling heating 14 second heat exchanger 15 third heat exchanger 16 fourth heat exchanger 17 Throttle 18 Valve, shut-off valve
Claims
[1] Cryotank system, comprising a first cryotank device (1), a second cryotank device (2) and a consumer (3), wherein the first cryotank device (1) comprises a first cryotank (4) and the second cryotank device (2) comprises a second cryotank (5), in particular each for holding hydrogen, wherein the first cryotank device (1) and the second cryotank device (2) are designed for parallel operation, so that the medium stored in the first and second cryotanks (4, 5) can be supplied to the consumer (3) simultaneously both from the first cryotank (4), via a first withdrawal line (6), and from the second cryotank (5), via a second withdrawal line (7), wherein the first cryotank device (1) comprises a first electrical heater (8) for heating the medium in the first cryotank (4), wherein the cryotank system comprises at least one control unit,wherein the first electric heater (8) can be activated and / or deactivated by the control unit, characterized by that the control unit is designed, after refueling of the first cryotank (4) and the second cryotank (5), i.e. at a refueling end time, to heat only the medium of the first cryotank (4) by activating the first electrical heater (8) and not to heat the medium of the second cryotank (5). [2] Cryogenic tank system according to claim 1, characterized by that the first extraction line (6) and the second extraction line (7) are fluidly connected to one another at a connection point and are fluidly connected to the consumer (3) from the connection point via a common consumer line (9). [3] Cryotank system according to claim 2, characterized byin that a valve (10), in particular a check valve, is arranged in the second withdrawal line (7), wherein the valve (10) prevents the medium from flowing from the first withdrawal line (6) into the second withdrawal line (7) at least after refueling of the first cryogenic tank (4) and the second cryogenic tank (5), i.e. at the end of refueling. [4] Cryotank system according to at least one of the preceding claims, characterized byin that the first cryogenic tank device (1) comprises a first recycling heater (11), wherein a partial flow of the first withdrawal line (6) is guided through a first heat exchanger (12) arranged in the first cryogenic tank (4) and is returned to the first withdrawal line (6) after the first heat exchanger (12), and / or wherein the second cryogenic tank device (2) comprises a second recycling heater (13), wherein a partial flow of the second withdrawal line (7) is guided through a second heat exchanger (14) arranged in the second cryogenic tank (5) and is returned to the second withdrawal line (7) after the second heat exchanger (14). [5] Cryotank system according to at least one of the preceding claims, characterized bythat the control unit is designed to heat the medium of the second cryotank (5) after a predefined pressure build-up in the first cryotank (4) by heating the medium of the first cryotank (4) by the first electric heater (8), i.e. at a pressure build-up time. [6] Cryogenic tank system according to claim 5, characterized by that the control unit is designed to heat the medium of the second cryotank (5) at the end of the pressure build-up time by activating a second electrical heater in the second cryotank (5). [7] Cryotank system according to claims 3 and 5, characterized bythat the control unit is designed to heat the medium of the second cryogenic tank (5) at the end of the pressure build-up time by deactivating the valve (10), in particular the check valve, by which a flow of the medium from the first withdrawal line (6) into the second withdrawal line (7) is prevented at least after refueling of the first cryogenic tank (4) and the second cryogenic tank (5), i.e. at the end of refueling time. [8] Cryotank system according to claim 5, characterized by that the control unit is designed to heat the medium of the second cryotank (5) at the end of the pressure build-up time by establishing a flow connection between the first cryotank (4) and the second cryotank (5), in particular by establishing a flow connection via a boil-off line or via a refueling transfer line. [9] Cryotank system according to claim 5, characterized bythat the control unit is designed to heat the medium of the second cryotank (5) at the end of the pressure build-up time by establishing a flow connection from the first cryotank device (1) to the second recycling heater (13).