DE-ICING AN AIRCRAFT USING A HYDROGEN REFORMER

Description

[0001] The invention relates to the de-icing or de-icing of components of an aircraft.

[0002] From DE 10 2004 058 430 B4, a supply system for energy provision in an aircraft is known, which comprises: at least one engine for propelling the aircraft, a fuel cell for supplying the aircraft with electrical energy, and a wing de-icing device that is coupled to the fuel cell in such a way that a wing of the aircraft can be de-iced by means of water vapor produced during the operation of the fuel cell, wherein the water vapor, which is the fuel product of the fuel cell, is condensed before wing de-icing to obtain water, heated as the remaining fuel product by means of a heat pump, and then supplied to the wing de-icing device.

[0003] From WO 2006 / 058774 A2, a power supply system for an aircraft is known, comprising a machine for propelling the aircraft, a fuel cell for supplying the aircraft with electrical energy, a first fuel tank for supplying the machine with engine fuel, and a second fuel tank for supplying the fuel cell with fuel. The first fuel tank is arranged separately from the second fuel tank.

[0004] From EP 2 268 545 B1, a de-icing system for an aircraft is known. This system comprises at least one heat source, at least one air discharge means for directing air into areas of the aircraft to be de-iced, and at least one air heating device. The air discharge means is directly connected via the air heating device to a duct system that draws exhaust air from a cabin of the aircraft, the air heating device absorbing heat from the at least one heat source to warm the exhaust air from the cabin.

[0005] From WO 2013 / 1 40306 A1, a wing icing protection system is known which includes a fuel cell system, a heat exchanger and a fluid circuit, and which uses a selection of electricity and other by-products such as water, heat and oxygen-depleted air, generated by the said fuel cell system, for the said wing icing protection and other local peripheral applications on an aircraft.

[0006] A fuel cell-based power supply system for an aircraft is also known from US 2007 / 0 172 707 A1. The waste heat from the fuel cell can be used for a de-icing system, which heats the aircraft's wing edges to prevent icing.

[0007] From FR 2 996 064 A1, a system is known with a heat-emitting power module, wherein the power module comprises at least one fuel cell with an anode and a cathode and at least one reformer, wherein the anode is supplied with hydrogen by the reformer and the cathode is supplied with oxygen. The system includes a circulation circuit for a consumable fluid, wherein this circulation circuit comprises at least one heat exchanger, which includes a heating circuit thermally coupled to the power module and a heated circuit coupled to the circulation circuit, wherein the heating circuit exchanges heat with the heated circuit and thus heats the consumable fluid.

[0008] The object of the present invention is to propose improvements relating to the de-icing of aircraft components.

[0009] The problem is solved by a method according to claim 1. The method serves, or is designed, for de-icing at least one component of an aircraft. Components include, in particular, rudders, flaps, turbine inlets, wing leading edges, etc. The method assumes, or is designed to assume, the following intended aircraft: "Intended" means that the method is tailored to a specific aircraft or type and is designed for use there; for example, it is designed for the resulting geometric / thermal requirements, etc. In other words, the aircraft in question is assumed to be known with respect to such properties, etc.

[0010] The aircraft contains a reformer. During operation, the reformer produces a reformate containing hydrogen through a reforming process. The reformer is therefore also called a hydrogen generation system. This reforming process also generates waste heat. Some of this waste heat is contained in the produced reformate and / or hydrogen. The aircraft also contains a fuel cell. This fuel cell is powered by the hydrogen produced by the reformer. In this process, at least when de-icing is required, the waste heat from the reformer is transported to the component via a heat channel. "Waste heat" in this context refers to at least a portion of the total waste heat from the reformer. Specifically, it refers only to the portion of the total waste heat that is actually fed into the heat channel and directed to the components.Furthermore, heat losses related to the transport, etc., of waste heat will not be considered here.

[0011] The transport process uses waste heat to warm the component and thereby de-ice it. A side effect is the dissipation of this waste heat to the aircraft's surroundings, thus removing it from the aircraft. The heat channel can have branches to other components requiring de-icing or to heat sinks, as described below. The channel can also be supplied with waste heat from multiple reformers. There can also be several channels supplied with waste heat from the same or different reformers. Both the introduction of the waste heat (or its components, see below) and its discharge to the component (or heat sink, see below) can occur at any point along the heat channel.

[0012] Gases or liquids are particularly suitable as heat-carrying / transporting media in the heat channel, transporting the waste heat from the reformer component and / or to the heat sink (see below) at least along part of the transmission path. In other words, at least one section of the heat channel is then designed as a gas-carrying or liquid-carrying channel / pipeline. The heat-carrying / transporting media can be circulated, especially liquids. This leads to savings in the consumption of the respective medium.

[0013] "De-icing" here refers to the actual removal of ice already present on or around the component. However, it can also be understood as the preventative measure of warming to prevent ice formation on the component; thus, "de-icing" here can also be understood as ice prevention. For the sake of simplicity, the term "de-icing" will be used throughout, although it may also refer to preventative warming, i.e., ice prevention.

[0014] Unless explicitly stated otherwise, the following explanations refer specifically to the normal operation of the reformer and the fuel cell, i.e., static or consistent, typical operating conditions. Highly dynamic conditions or special operating modes, such as changes in the operating mode of the fuel cell or the reformer (switching on, switching off, purging, etc.), will not be considered here. The reformer produces hydrogen primarily in the form of, or as part of, a reformate, which contains other products in addition to hydrogen. Specifically, the reformer produces the reformate, or hydrogen, from a propylene glycol-water mixture ("PGW').

[0015] According to the invention, the heat required in the de-icing system or de-icing device or the aircraft for de-icing components does not have to be generated by the engine in the form of bleed air or electrical power from, for example, kerosene, but the waste heat from a reformer of a fuel cell can be used.

[0016] Another advantage of the invention is that no additional subsystem is required for the disposal of the waste heat from the hydrogen generation system, but rather the de-icing device (see below, heat channel, component, heat sink, ...) is used.

[0017] The invention is based on the idea that fuel cells are increasingly being used in aircraft. For example, electrical energy for a passenger cabin / galley could be generated within the galley (gallery) as an alternative to the generators on the thrust engines. Such energy-generating systems could include a fuel cell system, i.e., one or more fuel cells and one or more reformers or hydrogen generation systems. The starting fuel for this is, for example, a propylene glycol-water mixture (PGW). This is a liquid, very safe, non-toxic fuel that can be produced regeneratively in large quantities. Hydrogen for the fuel cell system is produced from the PGW using a reformer (also called a "hydrogen generation system," "fuel processor system," or "complete reformer"). The hydrogen generation system delivers a gas mixture, called reformate, whose main component is hydrogen.Other components of the gas mixture are nitrogen, carbon dioxide, and water vapor. Due to the efficiency of the fuel cell system (approximately 50%) and the hydrogen production system (85% to 95%), the majority of the energy is released as heat / waste heat (approximately 53% to 57%). Only a small portion of this waste heat can be used in the cabin, for example, in the galley, as the temperature of the fuel cell's waste heat (approximately 60°C) is too low to heat meals or prepare hot beverages.

[0018] The invention is based on the idea of ​​increasing the efficiency of the fuels (e.g., kerosene) or propellants (e.g., hydrogen hydrogen) consumed in the overall aircraft system. According to the invention, the heat / energy present in the propellant (hydrogen hydrogen) is utilized more effectively. Therefore, the present invention proposes supplying and utilizing the waste heat from the hydrogen generation system to the de-icing device. This utilization of waste heat reduces engine fuel consumption, as, for example, less or no bleed air is required. The idea of ​​the invention is, in particular, to utilize the existing de-icing device (also called "de-icing system") or its infrastructure, especially an existing heat channel (i.e., without additional components), to dissipate the waste heat from the reformer and simultaneously save fuel.

[0019] According to the process, at least an initial portion of the waste heat from the reformer is generated in the form of heated exhaust gas from the reforming process. This exhaust gas is produced as a byproduct of reformate production from the fuel (especially PGW). The exhaust gas is routed through the heat channel to the component to heat it and thus de-ice it. Such an exhaust gas flow typically has a temperature of 100 to 150 °C. The exhaust gas is directed from the reformer directly into the heat channel and then through the heat channel to the component. Specifically, the component is directly exposed to the exhaust gas, i.e., without the use of additional heat exchangers or other intermediate heat exchangers. The exhaust gas then escapes into the aircraft environment during or after the component has been heated.

[0020] The background to this embodiment is as follows: In addition to the desired product, namely the hydrogen-containing reformate, the reformer also delivers the waste product heat in the form of a hot exhaust gas stream, which is the exhaust gas of the reforming process. The temperature of the exhaust gas is typically between 100 and 150 °C. If this temperature should be too high for, for example, a heat channel of an existing de-icing system (which is used here after conversion, see below), the exhaust gas can be mixed with air as a secondary gas and thus brought into a lower temperature range as a mixed gas. The components of the exhaust gas are, in particular, nitrogen, carbon dioxide, oxygen, and water vapor. The exhaust gas does not contain any toxic substances such as carbon monoxide or nitrogen oxides, as are known from combustion processes. The hot exhaust gas stream can be fed into the heat channel or...The exhaust gas is fed into the rest of the de-icing system, just as it could be with bleed air, or as is the case in systems known from practical experience. The exhaust gas then leaves the aircraft, in particular as has been the case with bleed air to date. This means the invention could easily be retrofitted into existing aircraft, see below.

[0021] Another aspect of the invention is therefore to not provide an additional subsystem for the disposal of the reformer's exhaust gas from the aircraft, but to use the existing pipes and outlets of the de-icing system (here the heat channel).

[0022] In a preferred embodiment of this system, as already mentioned above, a secondary gas is mixed with the exhaust gas after its generation in the reformer to obtain a mixed gas. The exhaust gas is then guided through the heat channel to the component to heat it. In particular, an end section of the heat channel facing the component or terminating at it is used, depending on the point in the heat channel where the secondary gas is added to the exhaust gas. Specifically, a secondary gas that is cooler than the exhaust gas is added to obtain a cooler mixed gas than the exhaust gas.

[0023] As described above, this serves primarily to lower excessively high exhaust gas temperatures. Furthermore, the addition of the secondary gas results in a higher quantity of mixed gas compared to exhaust gas, which is available for heating the component.

[0024] In a preferred embodiment of the method, it is assumed that the fuel cell generates cathode exhaust during operation, and at least a portion of this exhaust is fed to or returned to the reformer. The reformer processes the supplied cathode exhaust from the fuel cell into a cathode process gas and discharges it. At least a second portion of the waste heat from the reformer is thereby generated in the form of heated cathode process gas. This heated cathode process gas, together with the exhaust gas, is fed as a mixed gas through the heat channel to the component for heating. The cathode process gas has a temperature of 20 to 60 °C and / or is significantly more humid than the exhaust gas. Mixing it with the exhaust gas reduces the moisture content of the mixed gas; in other words, adding the exhaust gas to the cathode process gas dries the latter.

[0025] In this embodiment of the invention, it is proposed to utilize the waste heat from the reformer in the form of cathode process gas (modified cathode exhaust air from the fuel cell) and mix it with the exhaust gas. In this embodiment, the cathode exhaust air from the fuel cells is thus returned to the reformer, used and modified within the reformer process. The temperature of the cathode process gas can range between 20 and 60 °C, depending on the selected operating parameters of the reformer.The use of cathode process gas provides additional heat (the second part of the waste heat) for the heat channel / component (the de-icing system). Furthermore, the temperature of the mixed gas can be adjusted to a desired range, suitable for the de-icing system, i.e., the heat channel / component de-icing requirements, by adjusting the mixing ratio of the exhaust gas and the cathode process gas (again, only a portion of the latter can be used in the heat channel). Mixing exhaust gas and cathode process gas also eliminates a disadvantage that would arise from using only the cathode exhaust air from the fuel cell: the cathode exhaust air would first have to be dried by cooling and reheating, or cooled to extract water. The cathode process gas is moist, oxygen-depleted air and therefore non-toxic.The mixing with the relatively dry exhaust gas also reduces the risk of condensation forming in the heat channel / on the component, etc. (heat channel, for example, in the form of pipes), i.e., in the de-icing system. The mixed gas of exhaust gas and cathode process gas leaves the aircraft in this case as is the case with known bleed air applications, namely into the aircraft environment.

[0026] In a preferred embodiment, a specific mixing ratio of exhaust gas on the one hand and – depending on the embodiment and / or if present – ​​secondary gas and / or cathode process gas on the other hand is selected in the mixed gas. As explained above, this allows a specific desired temperature / humidity to be set or achieved in the mixed gas. The mixed gas can therefore contain the three components mentioned so far: exhaust gas, secondary gas, and cathode process gas. Further components can be included in the mixed gas, particularly if they transport additional waste heat; this embodiment applies accordingly in such cases.

[0027] In a preferred embodiment, the reformer includes an outlet cooler. This cooler serves to cool the reformate produced in the reformer, which contains hydrogen (as a component of the reformate). At least one-third of the waste heat is then generated by the reformer in the form of heated hydrogen / reformate. The reformer's cooler transfers this third portion of the waste heat from the hydrogen / reformate to the heat channel for transport to the component.

[0028] According to this embodiment, the waste heat from the reformer generated during the cooling of the reformate / hydrogen is utilized. The rationale behind this embodiment is that the reformate can or must be cooled – for example, before being fed into NTPEM (high-temperature polymer electrolyte membrane) fuel cells. This heat, typically generated in a heat exchanger, can be transferred to the heat channel / component (de-icing system). A cooling medium can circulate in this process, dissipating the heat absorbed by the hydrogen / reformat in the heat exchanger back into the heat channel / de-icing system.

[0029] In a preferred embodiment of this design, the cooler includes a heat exchanger that is thermally coupled on one side to the flow of the generated reformate containing the hydrogen, and on the other side to the heat channel. The third part of the waste heat is transferred from the hydrogen / reformate to the heat exchanger (e.g., its circulating cooling medium) and from there to the heat channel, e.g., the mixed gas flowing through it. The cooler can also be a heat exchanger in its entirety. All relevant components are thus thermally coupled to each other to transfer the third part of the waste heat to the heat channel.

[0030] In a preferred embodiment, the reformer includes a starter burner for the remaining part of the reformer, i.e., the actual reformer. At least a quarter of the waste heat transferred to the heat channel for transport to the component is then generated by the starter burner. This portion of the waste heat therefore does not originate from the reformer itself, but from the starter burner associated with it. In other words, in addition to the waste heat from the actual reformer (which carries out the reforming process from fuel to reformate / hydrogen), further waste heat from the starter burner (which brings the remaining reformer at least up to operating temperature) is used for introduction into the heat channel / heating the component. The statements made above regarding the coupling to the heat channel and the transfer of this fourth portion of the waste heat to it apply analogously.In particular, this allows for the introduction of additional gas / addition to the mixed gas, coupling via a further heat exchanger, etc. Here, too, there is the option of introducing the fourth part of the waste heat from the starter burner into the heat channel, either in gaseous form or in another form, for example, via a heat exchanger. According to this embodiment, the starter burner is also used for heat generation to provide heat for the defrosting system. Here, too, the waste heat, or the fourth part, can be fed in at any point in the heat channel.

[0031] In a preferred embodiment of the method, at least one of the components is supplied with waste heat not only for (actual) de-icing. As described above, such heating also serves, in particular, to prevent ice formation, i.e., to prevent ice from forming on the component in the first place. For example, waste heat can be supplied to the component whenever experience indicates a risk of icing. In particular, however, permanent ice prevention can also be established by continuously supplying the component with waste heat. "Continuous" here refers to the operation of the aircraft and means, for example, during the entire pre-flight preparation and flight. In this embodiment, it is therefore proposed to continuously supply / operate the de-icing system with waste heat in order to perform permanent de-icing.This corresponds to operation for anti-icing, i.e., permanent ice prevention. A conventional method of operating the de-icing system, as described above (i.e., only when needed), could therefore also be called "optional de-icing" in this sense.

[0032] In a preferred embodiment, when the fuel cell is inactive, the reformer is operated in a recycling plant where it internally consumes the hydrogen it produces. This embodiment is based on the following considerations: The reformer (hydrogen generation system) always delivers waste heat as a byproduct whenever there is a demand for electrical power from the fuel cell system and hydrogen must be produced to meet this demand. Without further measures, it could not be guaranteed that waste heat would actually be generated by the reformer whenever needed. This is because it is not certain that electrical power will be drawn from or required by the fuel cell, and thus that hydrogen will be required. Therefore, shutting down hydrogen production in the reformer for this reason would also mean that no waste heat would be available for the component.The present embodiment is based on the idea of ​​operating the reformer in a recycling mode. In this mode, only a relatively small amount of hydrogen is produced, and this is not consumed by the fuel cell but rather internally within the reformer, for example, to maintain the reformer at operating temperature. This allows the reformer to increase hydrogen production at any time, thereby quickly supplying the fuel cell with hydrogen by ramping up its hydrogen output.

[0033] This recycling operating mode is now used, according to the embodiment, to ensure the de-icing function, even if no electrical power is required from the fuel cell, but de-icing / ice prevention must still be ensured – for example, due to the flight phase. For this purpose, more heat / waste heat is generated in recycling mode than the hydrogen generation system would internally require, for example, to maintain its operating temperature. The excess heat is then available again as waste heat and, as explained above, is introduced into the heat channel and transported to the component.

[0034] In a further preferred embodiment, the aircraft incorporates a heat sink for dissipating waste heat into the environment. The heat sink is, in particular, part of the de-icing system. At least a portion of the reformer's waste heat is then transported via the heat channel not to the component itself, but to the heat sink, from where it is dissipated into the aircraft's environment. This occurs continuously. The heat sink thus forms a thermal interface with the aircraft's environment. Specifically, the heat sink is a part of the aircraft that does not require de-icing. This embodiment is based on the idea of ​​heating parts, especially surfaces of the aircraft, that do not require de-icing, for example, the entire wing area. This allows more waste heat / heat to be released into the aircraft's environment than was previously possible with a de-icing system that relied on components that require de-icing at least occasionally.In this way, a major problem in the operation of fuel cells (including their reformers) in aircraft can be solved: the disposal of waste heat – especially from the fuel cells themselves, not just the hydrogen generation system. As explained above, approximately half of the energy from the hydrogen in the fuel cells, including the reformer, is released as heat / waste heat during power generation. A solution is needed for this waste heat, particularly in the context of electric flight. Depending on the aircraft size, the heat output can range from a few kilowatts to several megawatts. Transferring this heat to a heat sink solves this problem. Alternatively or additionally, in a preferred embodiment, the heat output to be disposed of can also be transferred – at least partially – from the fuel cell to the component. This can also be achieved by interposing a heat exchanger and / or a heat channel.

[0035] The object of the invention is also achieved by a method according to claim 11 for retrofitting an aircraft. This (initial) aircraft contains a de-icing device. This device includes a heat channel that leads from a heat source to a component to be de-iced when necessary. The heat channel serves to transport heat from the heat source to the component in order to heat it and thereby de-ice it, at least when necessary, or to prevent de-icing, as described above. In this method, the aircraft is optionally retrofitted with a reformer and / or a fuel cell, so that both are ultimately present. This applies if such components are not already present in the aircraft in the appropriate design, dimensions, etc. Otherwise, the existing components are used.

[0036] Furthermore, the heat channel is modified to transport waste heat from the reformer to the component, at least in addition to, or especially instead of, the heat. The aircraft is further modified to be able to execute the inventive method within the aircraft. This is achieved in particular by operating the reformer or its components, controlling a mixer for the mixed gas, etc. Specifically, a control device is installed or configured for this purpose, e.g., by programming a digital computer or similar. The conversion method and at least some of its possible embodiments, as well as their respective advantages, have already been explained in substance in connection with the above-described method for de-icing at least one aircraft component.

[0037] In particular, the aircraft is also equipped to perform de-icing as described above and / or to heat the heat sink. In corresponding embodiments, the aircraft is therefore retrofitted with a suitable additive for a secondary gas / cathode process gas to the exhaust, a starting burner, a heat exchanger, a heat sink, etc., as described above.

[0038] In particular, the procedure involves retrofitting the de-icing device described below, or at least its components that are not yet present, in the aircraft.

[0039] The object of the invention is also achieved by a de-icing device according to claim 12 for an aircraft. It is assumed that the aircraft contains: the reformer described above, which is configured to generate hydrogen and the waste heat generated during operation in a reforming process; the fuel cell mentioned above, which is configured to be operated with the hydrogen generated in the reformer; and the component to be de-iced when necessary.

[0040] The de-icing device includes the aforementioned heat channel leading at least from the reformer to the component. This channel can be thermally coupled to both the reformer (including any components such as the cooler or starter burner, etc.) and the component / heat sink for transferring the waste heat (of the components described above), or is coupled in an assembly state. The de-icing device is designed to carry out the de-icing procedure described above for at least one aircraft component.

[0041] The de-icing device and at least some of its possible embodiments, as well as their respective advantages, have already been explained in substance in connection with the methods according to the invention.

[0042] In particular, according to the embodiments mentioned above, the de-icing device or the aircraft required in this sense has further components mentioned above, such as a supply means for the secondary gas / cathode process gas to the exhaust gas, the starter burner, the heat sink, etc.

[0043] The heat channel is a gas channel designed to convey a gas. The transport of waste heat through the heat channel is therefore achieved by passing through the gas carrying the waste heat (exhaust gas, mixed gas, etc.). The corresponding embodiment has already been explained above.

[0044] The object of the invention is also achieved by an aircraft according to claim 13. This aircraft includes the de-icing device according to the invention, as well as the reformer, fuel cell, and component mentioned in this context. Optionally, the aircraft has the further additional features mentioned above, such as a gas channel, starter burner, means for supplying the secondary gas, etc.

[0045] The invention is based on the following findings, observations, and considerations and further comprises the following preferred embodiments. These embodiments are sometimes referred to simply as "the invention." The embodiments may also include parts or combinations of the embodiments mentioned above, correspond to them, and / or may include previously unmentioned embodiments.

[0046] The invention is based on the idea of ​​proposing an alternative for supplying energy / heat to aircraft de-icing systems. Depending on the flight phases, devices must be present in the aircraft to prevent ice formation on components or to remove ice that has already formed. These devices require energy to heat the components.

[0047] The invention is based on the realization that heat from the thrust engines, in the form of bleed air, could be used for de-icing. The realization also lies in the fact that, in older aircraft designs, hot, compressed air (bleed air) could be extracted from the engines or the auxiliary power unit (APU) and supplied to the de-icing system / components via piping. The hot air enters the aircraft through small openings in the de-icing system and reaches specific areas / components, such as the wing leading edges, flaps, and engine inlets, that require heating during certain phases of flight to prevent or remove ice formation. After the hot air has transferred most of its heat to the component, it escapes into the atmosphere surrounding the aircraft.

[0048] The invention is based on the understanding that the bleed air extracted from the engines represents an energy loss for the engine's primary purpose, namely propulsion. This energy loss results in higher fuel (kerosene) consumption, and therefore de-icing systems are only activated during flight phases where their use is necessary. A key feature of existing de-icing systems is their ability to be switched on and off. According to the invention, this feature is no longer required.

[0049] The invention is also based on the realization that electrical energy could be used for defrosting, namely to generate heat from it. Electrical energy could be preferentially used where low heating loads are required or where supplying the energy via cable is simpler than with a warm medium that has to be conveyed through pipes. The effort required for generating and distributing bleed air would thus be avoided. However, this approach is not necessary according to the invention.

[0050] The invention is also based on the recognition that recent developments focus on providing energy in aircraft using fuel cells. It is possible to utilize waste heat from the fuel cells for de-icing. This approach is extended according to the invention.

[0051] The invention is further based on the idea that hydrogen for fuel cells in aircraft can be advantageously supplied using reformers. The idea of ​​the invention is to use this reformer as a heat source for the provision of waste heat.

[0052] According to the invention, permanent ice prevention is achieved in particular through the synergistic use of heat sources in the form of parts / waste products of the reformer. A fuel cell system consisting of a fuel cell in combination with a reformer (also called a "complete reformer") offers the possibility of using waste heat for component de-icing and, in particular, serving as a preventive measure to avoid ice formation. In the event of icing, this can result in significant energy savings and thus a reduction in kerosene consumption, since the required energy then does not have to be drawn from the engine / APU / fuel cell / any other electrical source.

[0053] Further features, effects, and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. These figures are shown in schematic diagrams: Figure 1 shows an aircraft with a de-icing device in a schematic diagram.

[0054] Figure 1 Figure 1 shows – only symbolically indicated – an aircraft 2. This aircraft contains a reformer 4. During operation, the reformer 4 performs a reforming process. In this reforming process, the reformer 4 produces hydrogen 6 as part of a reformate 7 from a fuel 3, here a propylene glycol-water mixture (PGW). Waste heat 8 is also generated during the reforming process. This is shown in Figure 1 Generally represented symbolically by an arrow. How individual components of the waste heat 8 are generated in more detail is explained below.

[0055] The aircraft 2 also contains a fuel cell 10, which is powered by the hydrogen 6 produced by the reformer 4. In normal operation, the fuel cell 10 generates electrical energy 11. Thus, a current 40 (represented by arrows) of hydrogen 6 / reformer 7 flows from the reformer 4 to the fuel cell 10.

[0056] Aircraft 2 contains a component 12, in this example a wing leading edge. When necessary, i.e., during certain flight phases and under certain weather conditions, component 12 must be de-iced. Aircraft 2 contains a heat channel 14. For the purpose of this de-icing, the waste heat 8 from the reformer 4 is transported to component 12 via the heat channel 14. Using the waste heat 8, component 12 is heated and thereby de-iced.

[0057] A first part 16 of the waste heat 8 is generated by the reformer 4 in the form of heated exhaust gas 18 from the reforming process. The exhaust gas 18, and with it the first part 16 of the waste heat, is conveyed through the heat channel 14 to component 12 to heat it. After its generation in or discharge from the reformer 4, a secondary gas 20, in this case ambient air, is mixed with the exhaust gas 18. The sum or mixture of exhaust gas 18 and secondary gas 20 results in a mixed gas 22. This mixed gas 22 is introduced into the heat channel to introduce the exhaust gas 18. The exhaust gas 18 and the first part 16 of the waste heat 8 contained within it are thus transported as part of the mixed gas 22 through the heat channel 14 to component 12 to heat it. The mixed gas 22 is also transported or conveyed through the heat channel 14.

[0058] In an alternative embodiment, shown with dashed lines, the secondary gas 20 is introduced into the heat channel 14 downstream of the exhaust gas inlet 18 and mixed with the exhaust gas 18. The mixed gas 22 then only passes through an end section of the heat channel 14 that terminates at component 12.

[0059] During operation of the fuel cell 10, it generates cathode exhaust air 24. The cathode exhaust air 24 is supplied to or returned to the reformer 4. The reformer 4 processes (in Figure 1(Indicated by dashed lines) the cathode exhaust air 24 to cathode process gas 26. A second part 28 of the waste heat 8 is generated or discharged by the reformer 4 in the form of heated cathode process gas 26. The heated cathode process gas 26 is also mixed with the exhaust gas 18 to form the mixed gas 22, and the mixed gas 22, together with the exhaust gas 18 and the cathode process gas 26, is guided through the heat channel 14 to the component 12 to heat it. Here too (comparable to the secondary gas 20), the injection of cathode process gas 26 can only take place in a later section of the heat channel 14 in order to form the mixed gas 22 there (in Figure 1 (not shown in detail). Alternatively, cathode process gas 26 and / or secondary gas 20 can also be fed into the heat channel 14 upstream of the exhaust gas 18 (shown as dashed lines).

[0060] Exhaust gas 18, secondary gas 20, and cathode process gas 26 each have different temperature levels. A specific, selectable mixing ratio 30 (in Figure 1 (Only symbolically indicated) the mixing components (exhaust gas 18, secondary gas 20, cathode process gas 26) can be used to set a desired temperature in the mixed gas 22, which lies between the warmest and coldest supplied components. The heat channel 14 is therefore a gas channel designed for conveying gases. As described, the gases that can be used are exhaust gas 18, a secondary gas 20, cathode exhaust air 24, or the mixed gas 22, etc.

[0061] On its output side, i.e., towards the fuel cell 10, the reformer 4 contains a cooler 32 for cooling the generated reformate 7 or hydrogen 6. A third portion 34 of the waste heat 8 is generated by the reformer 4 in the form of heated reformate 7 or hydrogen 6. This third portion 34 of the waste heat 8 is extracted from the reformate 7 or hydrogen 6 by means of the cooler 32 of the reformer 4 and transferred to the heat channel 14, from which it is transported to component 12. Here, for example, the transfer to the heat channel 14 is shown further downstream. Alternatively, and not shown, the third portion 34 of the waste heat 8 can also be fed into the heat channel 14 further upstream, e.g., at its beginning, for example, together with the exhaust gas 18, the secondary gas 20, the cathode process gas 26, etc.

[0062] To fulfill this task, the cooler 32 contains a heat exchanger 36, shown here as a circuit, which is thermally coupled on one side to the flow 40 of the generated reformate 7, containing the hydrogen 6, and on the other side to the heat channel 14. The third part of the waste heat 8 is therefore transferred from the reformate 7, containing the hydrogen 6, to the heat exchanger 36 and from the heat exchanger 36 to the heat channel 14. This occurs through a Figure 1 The symbolically indicated circulating liquid heat exchanger medium 38, i.e., a fluid, is used. The waste heat, or the third part 34, is transferred to the heat channel 14 or to a medium flowing therein to component 12, here the exhaust gas 18 or mixed gas 22, etc.

[0063] The reformer 4 contains a starter burner 42. A fourth portion 44 of the waste heat 8 is generated by the starter burner 42. This fourth portion 44 of the waste heat 8 is also fed into the heat channel 14 and thus transported to component 12 to heat it. As already described above, the feed-in can occur at various points in the heat channel 14 (indicated here by dashed lines). The feed-in can also be in the form of gas, or the starter burner can be coupled to the heat channel 14 via another heat exchanger or the circulation of a transport / cooling medium, as explained above. For the sake of clarity, all of this is not shown in detail in the figure.

[0064] In this example, component 12 is continuously supplied with waste heat 8, i.e., throughout the entire operation of reformer 4, not only when icing occurs or is likely to occur. Therefore, permanent ice prevention is achieved at component 12.

[0065] Figure 1 Figure 2 also shows an alternative operating mode for the depicted aircraft. In this mode, no electrical energy 11 is required from fuel cell 10. Therefore, fuel cell 10 is switched off and consequently does not consume any hydrogen 6 from reformer 4. Fuel cell 10 is thus inactive. However, reformer 4 is not switched off but continues to operate in a recycling mode. In this mode, the generated hydrogen 6 is fed back into reformer 4 and consumed there to maintain reformer 4 at operating temperature. The recycling mode is shown in Figure 2. Figure 1 Indicated by dashed lines.

[0066] Excess waste heat 8 is still generated by the reformer 4, which is not used to maintain the temperature within the reformer itself. This waste heat 8 is therefore still available for heating or de-icing component 12, as described above.

[0067] In addition to component 12, aircraft 2 has another heat sink 48, in this case in the form of an entire wing. Heat sink 48 serves to dissipate any heat it may contain to the environment 50 of aircraft 2. A portion of the waste heat 8 is transported to heat sink 48 via heat channel 14 or a branch thereof. The transfer of waste heat 8 from reformer 4 to heat sink 48 occurs via a branch at any point in heat channel 14, or alternatively via a second heat channel 14, which is supplied with the relevant portion of the waste heat 8. The waste heat 8, or its corresponding portion, is then discharged from aircraft 2 to the environment 50 via heat sink 48. Thus, excess waste heat 8 that cannot be consumed in component 12 or elsewhere in aircraft 2 can also be dissipated from aircraft 2.

[0068] Optionally, waste heat from the fuel cell 10 itself can also be dissipated to the heat sink 48 and / or the component 12, as indicated by dashed arrows in Fig. 1 This is indicated. This can also be achieved – again optionally – by interposing a heat exchanger 56 (therefore also shown with a dashed line) and / or the heat channel 14.

[0069] The transport of waste heat 8 in the heat channel 14 is in Figure 1 further clarified by dashed arrows.

[0070] The present aircraft 2 was created by retrofitting an existing aircraft 2. The existing aircraft already contained a de-icing device 51. This in turn contained the heat channel 14 and a heat source 52 for supplying heat 54 into the heat channel 14. Thus, the component 12 could be de-iced from the heat source 52 using the heat 54.

[0071] As part of the conversion of aircraft 2, it was retrofitted with the previously missing reformer 4 and fuel cell 10. The heat channel 14 itself was retained and merely modified by thermal coupling or connection to the reformer to absorb the waste heat 8 from reformer 4 and transfer it to components 12 instead of heat 54. For this purpose, heat channel 14 was disconnected from heat source 52 and connected to reformer 4, with only minor modifications. The heat channel 14 itself, in its course within aircraft 2 towards components 12, was otherwise retained unchanged.

[0072] Heat source 52 was removed from aircraft 2, as indicated by the dashed line. Its heat 54 is no longer needed and has therefore been replaced by waste heat 8. Aircraft 2 was also modified to carry out the aforementioned procedure. In particular, permanent ice prevention and the removal of waste heat 8 via heat sink 48 were added.

[0073] The heat channel 14 is therefore now also part of a de-icing device 51 for the aircraft 2.

[0074] In summary, aircraft 2 contains the de-icing device 51, the reformer 4, the fuel cell 10 and component 12. Reference symbol list

[0075] 2 Aircraft 4 Reformer 6 Hydrogen 7 Reformate 8 Waste heat 10 Fuel cell 11 Electrical energy 12 Component 14 Heat channel 16 First part 18 Exhaust gas 20 Second gas 22 Mixed gas 24 Cathode exhaust 26 Cathode process gas 28 Second part 30 Mixing ratio 32 Cooler 34 Third part 36 Heat exchanger 38 Heat exchanger medium 40 Electricity 42 Start burner 44 Fourth part 46 Recycling operation 48 Heat sink 50 Environment 51 De-icing device 52 Heat source 54 Heat 56 Heat exchanger

Claims

1. Method for de-icing at least one component (12) of an aircraft (2), - the aircraft (2) comprising: - a reformer (4) which produces reformate (7), containing hydrogen (6), and waste heat (8) arising in the process in a reforming process during operation, - and a fuel cell (10) which is operated with the produced hydrogen (6) during operation, in the case of which method: - at least in the case of de-icing of the component (12) being required, the waste heat (8) of the reformer (4) is transported by means of a heat channel (14) to the component (12), in order to heat the latter by way of the waste heat (8) and, as a result, to de-ice it, characterized in that - at least a first part (16) of the waste heat (8) is produced by the reformer (4) in the form of heated exhaust gas (18) of the reforming process, - the exhaust gas (18) is conducted through the heat channel (14) to the component (12), in order to heat the latter.

2. Method according to Claim 1, characterized in that - a second gas (20) is added to the exhaust gas (18) after it has been produced in the reformer (4), in order to obtain a mixed gas (22), - the exhaust gas (18) is conducted with the mixed gas (22) through the heat channel (14) to the component (12), in order to heat the latter.

3. Method according to one of the preceding claims, characterized in that - cathode exhaust air (24) is produced by the fuel cell (10), - at least one part of the cathode exhaust air (24) is fed to the reformer (4), - the reformer (4) processes the cathode exhaust air (24) to form cathode process gas (26), - at least a second part (28) of the waste heat (8) is produced by the reformer (4) in the form of heated cathode process gas (26), - the heated cathode process gas (26) is conducted together with the exhaust gas (18) as mixed gas (22) through the heat channel (14) to the component (12), in order to heat the latter.

4. Method according to one of the preceding claims, characterized in that a defined mixing ratio (30) of exhaust gas (18) firstly and, if present, second gas (20) and / or cathode process gas (26) secondly is selected in the mixed gas (22).

5. Method according to one of the preceding claims, characterized in that - the reformer (4) comprises an output-side cooler (32) for cooling the produced reformate (7), comprising hydrogen (6), - and at least a third part (34) of the waste heat (8) is produced by the reformer (4) in the form of heated reformate (7) with hydrogen (6), and the third part (34) of the waste heat (8) is transferred by means of the cooler (32) from the reformate (7) with the hydrogen (6) to the heat channel (14) for transport to the component (12) .

6. Method according to Claim 5, characterized in that the cooler (32) comprises a heat exchanger (36) which is coupled thermally on one side to the flow (40) of the produced reformate (7), comprising the hydrogen (6), and on the other side to the heat channel (14), and the third part (34) of the waste heat (8) is transferred to the heat exchanger (36) and from there to the heat channel (14).

7. Method according to one of the preceding claims, characterized in that the reformer (4) comprises an ignition boiler (42) for the remaining reformer (4), and at least a fourth part (44) of the waste heat (8) is produced by the ignition boiler (42).

8. Method according to one of the preceding claims, characterized in that at least one of the components (12) is supplied with the waste heat (8) not only for de-icing purposes.

9. Method according to one of the preceding claims, characterized in that in the case of an inactive fuel cell (10), the reformer (4) is operated in a recycling mode (46), in which it internally consumes the hydrogen (6) which is produced by it.

10. Method according to one of the preceding claims, characterized in that the aircraft (2) comprises a heat sink (48) for outputting waste heat (8) into the surroundings (50), and at least one part of the waste heat (8) is transported via the heat channel (14) to the heat sink (48), in order to be dissipated via the latter to the surroundings (50).

11. Method for retrofitting an aircraft, the aircraft comprising a de-icing apparatus which has a heat channel which leads from a heat source to a component which is to be de-iced as required, in order to transport heat from the heat source to the component, in order to heat the latter with the heat and, as a result, to de-ice it, in the case of which method: - the aircraft is possibly retrofitted with a reformer and / or a fuel cell, - the heat channel is upgraded, at least in addition to the heat, to transport waste heat of the reformer to the component, - and the aircraft is upgraded to carry out the method according to one of Claims 1-10 in the aircraft.

12. De-icing apparatus (51) for an aircraft (2), - the aircraft (2) comprising: - a reformer (4) which is configured to produce hydrogen (6) and waste heat (8) arising in the process in a reforming process during operation, - and a fuel cell (10) which is configured to be operated with the produced hydrogen (6) during operation, - a component (12) which is to be de-iced as required, - the de-icing apparatus (51) comprising a heat channel (14) which leads at least from the reformer (4) to the component (12) and can be thermally coupled to the reformer (4) and the component (12) for the transfer of the waste heat (8), - the de-icing apparatus (51) being configured to carry out the method according to one of Claims 1-10, characterized in that the heat channel (14) is a gas channel which is configured to conduct a gas.

13. Aircraft (2), with - the de-icing apparatus (51) according to Claim 12, - the reformer (4), - the fuel cell (10), - the component (12).