Heat exchanger - storage tank assembly for an aircraft

Abstract

The invention relates to a heat exchanger - storage tank assembly (20) for an aircraft having a fuel cell drive (10), the assembly comprising a heat exchanger (21) through which air can flow and at least two hydrogen storage tanks (16) for providing hydrogen for the fuel cell drive (10), and to an aircraft having a fuel cell drive (10) and a heat exchanger - storage tank assembly (20) of this type.

Description

[0001] Heat exchanger tank arrangement for an aircraft

[0002] The invention relates to a heat exchanger-tank assembly for an aircraft with a fuel cell drive, comprising a heat exchanger through which air can flow and a hydrogen tank for providing hydrogen for the fuel cell drive. The invention also relates to an aircraft with such a heat exchanger-tank assembly.

[0003] To achieve environmentally friendly aircraft design, efforts are being made to utilize fuel cells, particularly in the form of hydrogen-oxygen fuel cells, as energy sources for aircraft propulsion. To increase storage density in the tank, liquid hydrogen is typically used as the fuel source for the propulsion system, which requires high pressures within the hydrogen tank. In order for a hydrogen tank to provide sufficient stability and safety at high internal pressures, compliance with certain geometric requirements is necessary. With a changed geometric shape of hydrogen tanks, the conventional integration of these fuel storage devices into an area of ​​an aircraft wing is no longer possible.

[0004] During operation of the fuel cell propulsion system, a large amount of excess heat is generated in the fuel cell at a relatively low temperature level of approximately 90°C. To enable continuous operation of the propulsion system, an efficient heat management system is required. This excess heat can be dissipated into the ambient air, for example, using liquid-to-air heat exchangers. Due to the high heat quantities and the relatively small temperature difference between the ambient air and the coolant, large heat exchangers are required. Accordingly, the spatially and aerodynamically favorable integration of heat exchangers is currently a subject of research.

[0005] Based on this, it is an object of the present invention to improve the integration of components for an aircraft with a fuel cell drive. In particular, an aerodynamically favorable integration option for providing hydrogen for the fuel cell drive and / or a heat exchange system for the fuel cell drive is to be improved. This is achieved according to the invention by the teaching of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims.

[0006] To achieve the object, a heat exchanger-tank arrangement for an aircraft with a fuel cell drive is proposed, comprising a heat exchanger through which air can flow and at least two hydrogen tanks for providing hydrogen for the fuel cell drive, wherein the heat exchanger is arranged in front of the at least two hydrogen tanks in the direction of flight.

[0007] The proposed structural and spatial combination of hydrogen tanks and the heat exchanger (system) creates a particularly functional unit that can be positioned at different locations on the aircraft. This integration of tank(s) and heat exchanger can reduce overall air resistance compared to a configuration with two separate integration positions for the hydrogen tank(s) and the heat exchanger. In this context, the term "arrangement" can describe a functional unit of heat exchanger and hydrogen tanks and / or a spatial relationship between them.

[0008] According to a further aspect, an aircraft with a fuel cell drive is proposed, comprising at least one heat exchanger-tank arrangement as described herein. In an aircraft configured in this way, the heat exchanger-tank arrangement can be used to supply and / or cool the fuel cell system used to power the aircraft, with the proposed design of the heat exchanger-tank arrangement allowing variable positioning on or in the aircraft.

[0009] A fuel cell drive for an aircraft typically comprises a fuel cell system with a plurality of fuel cells, which are arranged, for example, in the form of fuel cell stacks. Such a fuel cell system, which accordingly comprises at least one fuel cell, is also referred to simply as "a fuel cell" in the context of the description of the invention. A fuel cell comprises at least one anode, which is supplied with a fuel, such as hydrogen, to generate electrical energy, and at least one cathode, which, in cooperation with the at least one anode, is supplied with ambient air, for example, to generate electrical energy in order to supply the atmospheric oxygen contained therein to the fuel cell as an oxidizing agent. To supply the anode with fuel, the anode can be connected to the at least two hydrogen tanks, for example by means of a process gas device.Such a process gas device can also be designed to supply the cathode with ambient air and to remove used process gases.

[0010] To generate energy, the fuel or hydrogen is catalytically oxidized at the anode, releasing electrons into hydrogen ions. These ions pass through the electrolyte, usually in the form of a membrane, into the cathode area, where they react with the oxygen supplied to the cathode and the electrons conducted to the cathode via an external circuit to form water. This process not only generates energy to propel the aircraft, but also generates heat.

[0011] To enable stable operation of the fuel cell system, it can be cooled by means of the heat exchanger or a cooling system comprising the heat exchanger or a coolant circuit. This coolant circuit can be connected to the heat exchanger, wherein the heat exchanger is configured to absorb heat generated by the at least one fuel cell and, in particular, transported to the heat exchanger by means of the coolant circuit, and to release it to the environment. For this purpose, the heat exchanger can have at least one cooling surface connected to the coolant circuit, over which an ambient air flow, for example in the form of a fan and / or ram air flow, can flow during operation. The cooling surface of the heat exchanger can absorb heat from the coolant circuit and dissipate it, in particular convectively, from the heat exchanger to the air flow.In this context, a cooling surface is any surface arranged on the heat exchanger which is heated by the heat energy to be dissipated and from which heat can be dissipated by an ambient air flow passing over it.

[0012] The invention is based on the idea of ​​providing a spatially integrated unit comprising hydrogen tank(s) and heat exchanger in order to reduce the air resistance of this unit and thus of the aircraft. For this purpose, the invention provides for at least two or more hydrogen tanks to be provided instead of a single hydrogen tank. This makes it possible, for example, to reduce the height of the tanks, as a result of which air resistance can be reduced. In order to provide an optimized arrangement for the heat exchanger and the at least two water tanks, it is also proposed to arrange the heat exchanger in front of the at least two hydrogen tanks in the direction of flight. In other words, the heat exchanger is arranged closer to the nose of the aircraft and the at least two hydrogen tanks are arranged closer to the tail of the aircraft. This makes it possible to duct the air orAir ducts of the heat exchanger can be integrated into the heat exchanger-tank arrangement in such a way that the overall length of the heat exchanger-tank arrangement can be reduced. Furthermore, the air can be routed at least partially along the at least two hydrogen tanks in order to remove escaping hydrogen and release it into the environment, for example, in the event of a leak in the area of ​​the hydrogen tanks. This can reduce the risk of explosion and thus increase the safety of the hydrogen supply.

[0013] In one embodiment, the at least two hydrogen tanks are substantially cylindrical. A cylindrical design of the hydrogen tanks allows for improved absorption of the high pressures that occur during hydrogen storage and the associated stress distribution within the tank. Depending on the system, the tank pressure can be approximately between 6 and 10 bar, whereby the cylindrical shape can improve the balance between the pressure load on the tanks and the ambient pressure.

[0014] In one embodiment, the hydrogen tanks have a length-to-diameter ratio of greater than 10. The following applies: length L to diameter D; L / D > 10. This results in long and thin pressure vessels, which can be arranged or are arranged on the aircraft, in particular in a longitudinal direction of the aircraft, in order to further reduce the aircraft's air resistance.

[0015] In another embodiment, the length-to-diameter ratio L / D of the hydrogen tanks can also be 10 or less than 10. This makes it possible to provide dimensions of the hydrogen tanks that are adapted to predetermined installation space requirements. In one embodiment, an air outlet of the heat exchanger is arranged between the at least two hydrogen tanks, so that the air flow of the heat exchanger can be guided at least partially along the at least two hydrogen tanks in order to then release it to the environment. In this case, the air outlet can be arranged, for example, between two cylindrically shaped and / or parallelly arranged hydrogen tanks, wherein an outlet opening of the air outlet is in a plane below the hydrogen tanks (e.g.When the heat exchanger-tank arrangement is positioned on the fuselage side of the aircraft, this can be arranged to guide the air flow from the heat exchanger-tank arrangement at least partially along the hydrogen tanks. The hydrogen tanks can, for example, be arranged laterally or transversely adjacent to the air outlet. Such an arrangement can reduce the length of the heat exchanger-tank arrangement. Furthermore, the air flow thus enabled can divert escaping hydrogen from the air flow to the environment, reducing the potential danger from incorrectly escaping hydrogen.

[0016] In one embodiment, an air outlet of the heat exchanger can have an air nozzle device. The air nozzle device is particularly designed to influence a mass flow of the air flow through the heat exchanger. By influencing the air flow in this way, for example, a cooling effect of the heat exchanger can be made adjustable, particularly with regard to a coolant flowing therein, and / or the discharge of hydrogen escaping from a hydrogen tank and / or a hydrogen-carrying line to the environment in the event of a fault can be favorably influenced. In this case, the air outlet can be arranged between the hydrogen tanks, as already described. In other embodiments, the air outlet can also be arranged at a different position.

[0017] In one embodiment, the air nozzle device comprises a metering plate that is displaceable, in particular, in the direction of flight and is configured to at least partially close the air outlet or its air outlet opening. Such a design enables an opening and / or closing movement of the metering plate in a longitudinal direction or in and against the direction of flight, in order to enable a particularly simple mechanical adjustment of the air nozzle device.

[0018] In one embodiment, the metering plate essentially has a contour of a casing of the heat exchanger-tank arrangement. The metering plate, which is designed to be displaceable in the direction of flight, in particular, can replicate the contour of the casing such that it can be displaced in the longitudinal direction in order to variably close or open the air outlet of the heat exchanger or its outlet opening without (significantly) influencing the air flow of the heat exchanger. The metering plate can have a geometry that follows the contour of the casing, in particular transversely to an adjustment or displacement direction, in order to keep air resistance low or reduce it regardless of a displacement position. In this case, the heat exchanger-tank arrangement can have a casing, which can be, for example, a housing of the heat exchanger-tank arrangement and / or part of an aircraft casing.

[0019] In one embodiment, the heat exchanger has at least two air inlets configured to supply ambient air to the heat exchanger for heat exchange. These air inlets can be arranged such that they are each arranged laterally relative to the landing gear of the aircraft, so that the incoming ambient air is not disturbed or influenced by the landing gear. This can improve the air flow quality at the heat exchanger inlet. By positioning the heat exchanger-tank assembly on the aircraft fuselage or in the area of ​​the landing gear in this way, integration of the heat exchanger-tank assembly in or on the aircraft can be improved.

[0020] In one embodiment, the heat exchanger-tank arrangement is arranged on a fuselage of the aircraft. As a result, the hydrogen tanks are arranged outside and / or at a distance from an aircraft cabin, whereby a risk emanating, for example, from a possible leak in a tank can be reduced, in particular because escaping hydrogen can be dissipated to the environment, for example by means of the air flow of the heat exchanger. This can, for example, reduce the risk of explosion, since the exhaust air from the heat exchanger enables the hydrogen tanks to be ventilated through or recirculated. In addition, arranging the heat exchanger-tank arrangement on the fuselage enables the fuel or one or more hydrogen line(s) and coolant line(s) to be routed outside the aircraft cabin.

[0021] In one embodiment, the heat exchanger tank assembly is arranged on the aircraft in such a way that the ambient air in the area of ​​the aircraft's landing gear can enter the heat exchanger tank assembly, in particular via the two described inlets. This allows ram air to be absorbed in an area of ​​the landing gear, thereby enabling structural integration of the heat exchanger tank assembly on or in the aircraft, which favorably influences the aircraft's aerodynamic drag.

[0022] Further features, advantages, and possible applications of the invention will become apparent from the following description in conjunction with the figures. In general, features of the various exemplary aspects and / or embodiments described herein may be combined with one another, unless clearly precluded in the context of the disclosure.

[0023] In the following part of the description, reference is made to the figures shown to illustrate specific aspects and embodiments of the present invention. It is understood that other aspects may be utilized and structural or logical changes to the illustrated embodiments are possible without departing from the scope of the present invention. The following description of the figures is therefore not to be understood as limiting. It shows

[0024] Fig. 1 is a schematic representation of an exemplary fuel cell drive for an aircraft with a heat exchanger tank arrangement according to the invention.

[0025] Figs. 2a to 2c each show a schematic representation of an exemplary heat exchanger-tank arrangement for a fuel cell-powered aircraft. Fig. 1 shows a schematic representation of an exemplary fuel cell drive 10 for an aircraft comprising a fuel cell system 12 and a heat exchanger-tank arrangement 20 according to the invention.

[0026] The fuel cell system 12 is configured to provide energy for the fuel cell drive 10. According to the invention, the heat exchanger-tank arrangement 20 comprises a heat exchanger 21 through which air can flow and at least two hydrogen tanks 16 for providing hydrogen for the fuel cell drive 10 or the fuel cell system 12.

[0027] The fuel cell system 12 has a fuel cell 13 with an anode 14 and a cathode 15. The anode 14 is supplied with hydrogen from the two hydrogen tanks 16 via a process gas device 17. The hydrogen is largely consumed in the fuel cell 13, and a consumed process gas or the anode-side reaction gas can be discharged from the fuel cell 13. Hydrogen that is not completely consumed can be fed back to the anode 14 of the fuel cell 13, for example by means of gas recirculation (not shown), or released into the environment. The cathode 15 is supplied with ambient air taken from the environment 18 and reacts as a process gas in the fuel cell 13. The consumed ambient air or the cathode-side reaction gas can be discharged from the fuel cell 13 and, in particular, released into the environment 18.

[0028] Heat generated by the fuel cell system 12 during the energy generation process can be transported by means of a cooling fluid via a coolant circuit 30 to the heat exchanger 21, where the heat is released to the environment by means of the heat exchanger 21. For this purpose, the cooling fluid can be conducted via the coolant circuit 30 to the fuel cell system 12, absorb heat there, and be discharged from there via the coolant circuit 30. To cool the cooling fluid, it is fed via the coolant circuit 30 to the heat exchanger 21, where heat is extracted from it. The cooling fluid can then be discharged from there via the coolant circuit 30 and made available again to the fuel cell system 12. Fig. 2a shows a schematic representation of an exemplary heat exchanger-tank arrangement 20 for an aircraft with a fuel cell drive 10 in a side view.In the illustrated embodiment, the heat exchanger tank arrangement 20 is shown in an exemplary position on an aircraft fuselage (not further shown).

[0029] The heat exchanger-tank arrangement 20 has a heat exchanger 21 through which air can flow, and at least two hydrogen tanks 16 arranged downstream of the heat exchanger 21 in the direction of flight F. The parallel hydrogen tanks 16, of which only one is visible in the present illustration, are essentially cylindrical in design to provide sufficient stability with respect to a pressure that may be present in the hydrogen tank 16. The ratio of a length L to a diameter D of the cylindrical tank 16 is greater than 10. This results in an aerodynamically favorable geometry for the hydrogen tanks 16, which can reduce air resistance.

[0030] An air inlet 22 of the heat exchanger 21 is arranged relative to the aircraft such that the ambient air in the region of a landing gear 40 of the aircraft can enter the heat exchanger-tank arrangement 20. An air outlet 23 of the heat exchanger 21 is arranged in the region of the two hydrogen tanks 16, so that the air flow of the heat exchanger 21 can be guided at least partially past the hydrogen tanks 16 and thus, in the event of hydrogen escaping from a tank 16 or a line, can release it into the environment 18.

[0031] Fig. 2b shows a schematic representation of the exemplary heat exchanger tank arrangement 20 from Fig. 2a in a view from below.

[0032] The illustration shows that the heat exchanger 21 has two air inlets 22a, 22b, which are configured to receive ambient air and guide it as an air flow into the heat exchanger 21. The air inlets 22a, 22b are arranged on both sides of a landing gear 40 of the aircraft, so that the ambient air in the area of ​​the landing gear 40 can enter the heat exchanger-tank arrangement 20 without the air flow being negatively affected by the landing gear 40. The air outlet 23 of the heat exchanger 21 is arranged between the two parallel hydrogen tanks 16 and has an air nozzle device 24 configured to influence the air flow of the heat exchanger 21.

[0033] Fig. 2c shows a schematic detailed representation of the exemplary heat exchanger tank arrangement 20 from Figs. 2a and 2b in a side view.

[0034] The air nozzle arrangement 24 arranged at the air outlet 23 has a metering plate 25 that is displaceable in the longitudinal direction R and is designed to at least partially close the air outlet 23 in order to influence or regulate a mass flow of the air flow of the heat exchanger 21. The metering plate 25 essentially has a contour of a casing of the heat exchanger-tank arrangement 20, so that it does not negatively influence air resistance.

[0035] LIST OF REFERENCE SYMBOLS

[0036] 10 Fuel cell drive

[0037] 12 Fuel cell system

[0038] 13 Fuel cell

[0039] 14 Anode

[0040] 15 Cathode

[0041] 16 Hydrogen tank

[0042] 17 Process gas system

[0043] 18 Surroundings

[0044] 20 Heat exchanger tank- An order

[0045] 21 heat exchangers

[0046] 22 Air intake

[0047] 22a Air inlet

[0048] 22b Air intake

[0049] 23 Air outlet

[0050] 24 Air nozzle device

[0051] 25 Dosing plate

[0052] 30 Coolant circuit

[0053] 40 Landing gear of an aircraft

[0054] F Flight direction

[0055] R Longitudinal direction

[0056] L Length of the hydrogen tank

[0057] D Diameter of the hydrogen tank

Claims

CLAIMS 1. Heat exchanger tank arrangement (20) for an aircraft with a fuel cell drive (10), comprising a heat exchanger (21) through which air can flow and at least two hydrogen tanks (16) for providing hydrogen for the fuel cell drive (10), wherein the heat exchanger (21) is arranged in front of the at least two hydrogen tanks (16) in the direction of flight (F).

2. Heat exchanger tank assembly (20) according to claim 1, wherein the at least two hydrogen tanks (16) are substantially cylindrical.

3. Heat exchanger tank arrangement (20) according to at least one of claims 1 or 2, wherein the hydrogen tanks (16) have a length-diameter ratio (D / L) of greater than 10.

4. Heat exchanger tank arrangement (20) according to at least one of the preceding claims, wherein an air outlet (23) of the heat exchanger (21) is arranged between the at least two hydrogen tanks (16), so that an air flow of the heat exchanger (21) can be guided at least partially along the at least two hydrogen tanks (16).

5. Heat exchanger tank arrangement (20) according to at least one of the preceding claims, wherein the air outlet (23) of the heat exchanger (21) has an air nozzle device (24) which is designed to influence an air flow of the heat exchanger (21).

6. Heat exchanger tank assembly (20) according to claim 5, wherein the air nozzle device (24) comprises a displaceable metering plate (25) which is arranged to at least partially close the air outlet (23).

7. Heat exchanger tank assembly (20) according to at least one of claims 5 or 6, wherein the metering plate (25) substantially has a contour of a cladding of the heat exchanger tank assembly (20).

8. Heat exchanger tank assembly (20) according to at least one of the preceding claims, wherein the heat exchanger (21) has at least two air inlets (22a, 22b).

9. Aircraft with a fuel cell drive (10), comprising a heat exchanger tank arrangement (20) according to at least one of the preceding claims.

10. Aircraft according to claim 9, wherein the heat exchanger tank assembly (20) is arranged on a fuselage of the aircraft.

11. Aircraft according to at least one of claims 9 or 10, wherein the heat exchanger tank arrangement (20) is arranged on the aircraft in such a way that the air can enter the heat exchanger tank arrangement (20) in the region of a landing gear (40) of the aircraft.

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