Hydrogen fuel thermal conditioning system and method of thermally conditioning hydrogen fuel

Abstract

Disclosed is a hydrogen fuel thermal conditioning system 1, having a fuel supply system 100 and an energy transfer system 200. The fuel supply system comprises a tank 23 configured to store hydrogen f

Description

TECHNICAL FIELD

[0001] The present invention relates to hydrogen fuel thermal conditioning systems and methods of thermally conditioning hydrogen fuel. BACKGROUND

[0002] Hydrogen fuel may be supplied to aircraft during a fueling process. The hydrogen fuel may be stored in a cryogenic liquid state in a hydrogen fuel supply system. The hydrogen fuel supply system may be connectable to a fuel tank of the aircraft, for instance when the aircraft is on the ground, and supplied to the fuel tank of the aircraft in a cryogenic liquid state. SUMMARY

[0003] A first aspect of the present invention provides a hydrogen fuel thermal conditioning system, comprising: a fuel supply system comprising a tank configured to store hydrogen fuel and an outlet fluidically connectable to a recipient system, the fuel supply system configured to transfer hydrogen fuel from the tank to the recipient system via the outlet; and an energy transfer system comprising an inlet fluidically connectable to a source system, the energy transfer system configured to receive source hydrogen fuel from the source system via the inlet, and to use energy from the source hydrogen fuel to heat the hydrogen fuel in the fuel supply system.

[0004] Hydrogen fuel has a high energy density (per mass) relative to other fuels. As such, less of the source hydrogen fuel from the source system may be required to sufficiently heat the hydrogen fuel in the fuel supply system than other sources of energy, such as other, non-hydrogen, fuels. This may provide an efficient arrangement for heating the hydrogen fuel in the fuel supply system. It may also, or alternatively, be possible to heat the hydrogen fuel in the fuel supply system to a greater extent for a given quantity of the source hydrogen fuel compared to the same quantity of another fuel. This may similarly provide a system that is more efficient at heating the hydrogen fuel in the fuel supply system than systems utilising other types of fuel.

[0005] Optionally, the recipient system comprises a recipient fuel tank, the outlet is fluidically connectable to the recipient fuel tank, and the fuel supply system is configured to transfer hydrogen fuel from the tank to the recipient fuel tank via the outlet. Optionally, the source system comprises a source fuel tank, the inlet is fluidically connectable to the source fuel tank, and the energy transfer system is configured to receive the source hydrogen fuel from the source fuel tank via the inlet. Optionally, the recipient system comprises both the recipient fuel tank and the source fuel tank. Optionally, the recipient fuel tank and the source fuel tank are the same recipient fuel tank. In other words, the hydrogen fuel in the fuel supply system that is to be supplied to the recipient fuel tank may be heated using energy from source hydrogen fuel that is received from the same recipient fuel tank. This may provide an efficient arrangement, whereby a return flow of (source) hydrogen fuel from the recipient fuel tank is used to heat a supply flow of hydrogen fuel to the recipient fuel tank. The return flow of source hydrogen fuel may be gaseous hydrogen fuel that is vented from the recipient fuel tank during fuelling of the recipient fuel tank. Utilising this source hydrogen fuel to heat the hydrogen fuel in the fuel supply system may reduce a wastage of the source hydrogen fuel, which may otherwise be combusted and / or vented to the atmosphere.

[0006] Optionally, the hydrogen fuel thermal conditioning system is configured to be selectively operable in: a first mode, in which the hydrogen fuel thermal conditioning system heats the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel; and a second mode, in which the hydrogen fuel thermal conditioning system does not heat the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel.

[0007] Selectively configuring the hydrogen fuel conditioning system in the first configuration or the second configuration may allow the hydrogen fuel in the fuel supply system to have different properties, for instance different temperatures, depending on the requirements of the recipient system. In this way, the hydrogen fuel thermal conditioning system can be used to thermally condition fuel to be supplied to a variety of types of recipient system. Thus, the hydrogen fuel thermal conditioning system may be more versatile than a comparable system that is unable to selectively heat the hydrogen fuel in the fuel supply system.

[0008] Optionally, the energy transfer system comprises an energy converter configured to convert the energy from the source hydrogen fuel into heat energy, and to use the heat energy to heat the hydrogen fuel in the fuel supply system. The energy convertor may allow more of the energy contained in the source hydrogen fuel to be used to heat the hydrogen fuel in the fuel supply system, compared to a system that merely uses heat already contained in the source hydrogen fuel, for example.

[0009] The energy from the source hydrogen fuel may comprise chemical energy, and the hydrogen fuel may be reacted or combusted to convert the chemical energy into heat energy. Hydrogen fuel has a higher energy density (per mass) than other fuels, and so reacting or combusting the source hydrogen fuel to heat the hydrogen fuel in the fuel supply system may allow comparatively high rates of heat transfer to be achieved compared to reacting or burning other fuels. This may provide an efficient hydrogen fuel thermal conditioning system.

[0010] Alternatively, or in addition, the energy from the source hydrogen fuel may comprise heat energy. In such cases, the energy transfer system may be configured to transfer the heat energy from the source hydrogen fuel to the hydrogen fuel in the fuel supply system. In some examples, the energy transfer system comprises a source hydrogen fuel heat exchanger comprising a source side, through which is passable the source hydrogen fuel, and a supply side, through which is passable the hydrogen fuel from the fuel supply system to be heated. The source hydrogen fuel heat exchanger may be configured so that heat is transferred from the source hydrogen fuel in the source side to the hydrogen fuel in the supply side, in use.

[0011] Optionally, the energy converter comprises a catalyst bed in which the source hydrogen fuel is able to be reacted with a reactant to produce the heat energy. The catalyst bed may allow the energy from the source hydrogen fuel to be converted into the heat energy without requiring burning of the source hydrogen fuel. This may improve a safety of the hydrogen fuel thermal conditioning system, for instance by avoiding the presence of an open flame. Providing the catalyst bed also avoids the need for complex equipment for supporting and controlling such a flame, which may reduce a cost of the hydrogen fuel thermal conditioning system compared to one which combusts the source hydrogen fuel.

[0012] Optionally, the reactant is oxygen. Optionally, the catalyst bed is configured to facilitate a reaction of the source hydrogen fuel with oxygen to produce the heat and water, for example to produce heated steam. In this way, the energy from the source hydrogen fuel may be converted into heat energy whilst providing water as a byproduct. If the source hydrogen fuel were instead to be combusted, inefficiencies in the combustion process may result in byproducts other than water being produced. Moreover, it may be difficult to capture such byproducts produced by combusting the source hydrogen fuel, and so such byproducts may be simply released into the atmosphere. In contrast, with the catalyst bed, the water may be collected and utilised for other processes, which may provide a more efficient and resourceful hydrogen fuel thermal conditioning system. Optionally, the catalyst bed comprises platinum or palladium as a catalyst. Optionally, the catalyst bed comprises platinum or palladium dispersed on a ceramic matrix, such as an aluminium oxide (A1O3) ceramic matrix.

[0013] Optionally, the energy convertor is configured to provide an energy transfer fluid containing the heat energy. The energy transfer fluid may provide a convenient way of passing the heat energy from the energy transfer system to various parts of the hydrogen fuel thermal conditioning system. This may provide versatility in the relative locations of the energy convertor and the fuel supply system, and / or other components to which the heat energy from the energy convertor is to be provided.

[0014] Optionally, where the energy convertor comprises a catalyst bed configured to facilitate a reaction of the source hydrogen fuel with oxygen to produce heat and water, for instance in the form of heated steam, the energy transfer fluid comprises the heat and water. For instance, the energy transfer fluid may comprise the heated steam.

[0015] Optionally, the energy transfer system comprises a fuel supply heat exchanger configured to transfer the heat energy in the energy transfer fluid to the hydrogen fuel in the fuel supply system. The fuel supply heat exchanger may provide a convenient way of transferring the heat energy carried by the energy transfer fluid to the hydrogen fuel in the fuel supply system, for instance without requiring mixing of the energy transfer fluid and the hydrogen fuel in the fuel supply system.

[0016] Optionally, the fuel supply heat exchanger comprises a first side, through which is passable the energy transfer fluid, and a second side, through which is passable the hydrogen fuel in the fuel supply system to be heated. Optionally, the fuel supply heat exchanger is configured so that heat is transferred from the energy transfer fluid in the first side to the hydrogen fuel in the second side, in use.

[0017] Optionally, the hydrogen fuel thermal conditioning system comprises a collector configured to receive the energy transfer fluid downstream of the fuel supply heat exchanger, for instance downstream of the first side of the fuel supply heat exchanger, where provided. This may allow the energy transfer fluid to be collected and utilised for other purposes. For example, when the energy transfer fluid is water, which may be aqueous and / or gaseous water, for instance heated steam, the water may be collected in the collector, for instance in liquid form, and used in other processes requiring or benefitting from water. In this way, the source hydrogen fuel may be used to heat the hydrogen fuel in the fuel supply system, and then waste from this process may be re-used in other processes. This may reduce an amount of waste as compared to, for example, heating the hydrogen fuel in the fuel supply system using an electric heater, or by burning, or otherwise venting, the source hydrogen fuel.

[0018] Optionally, the hydrogen fuel thermal conditioning system is configured to selectively permit a flow of hydrogen fuel in the fuel supply system to the fuel supply heat exchanger. For instance, when the hydrogen fuel thermal conditioning system is configured to selectively heat the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel, this may be by the hydrogen fuel thermal conditioning system being configured to selectively permit a flow of hydrogen fuel in the fuel supply system to the heat exchanger.

[0019] Selectively permitting the flow of hydrogen fuel in the fuel supply system to the fuel supply heat exchanger may allow the hydrogen fuel in the fuel supply system to have different properties, for instance different temperatures, depending on the requirements of the recipient system. In this way, the hydrogen fuel thermal conditioning system can be used to thermally condition fuel to be supplied to a variety of types of recipient system. Thus, the hydrogen fuel thermal conditioning system may be more versatile than a comparable system that is unable to selectively heat the hydrogen fuel in the fuel supply system.

[0020] The fuel supply system may comprise a fuel supply isolation valve. The fuel supply isolation valve may be operable to selectively permit a flow of hydrogen fuel in the fuel supply system toward the first side of the fuel supply heat exchanger. Alternatively, or in addition, the fuel supply system may comprise a fuel supply divertor valve. The fuel supply divertor valve may be selectively positionable in: a first position, in which the fuel supply divertor valve directs a flow of hydrogen fuel in the fuel supply system toward a heat exchange flow path that passes through the first side of the fuel supply heat exchanger; and a second position, in which the fuel supply divertor valve directs the flow of hydrogen fuel in the fuel supply system toward a bypass flow path that bypasses the fuel supply heat exchanger.

[0021] Optionally, the hydrogen fuel thermal conditioning system is configured to selectively permit a flow of the energy transfer fluid to the fuel supply heat exchanger. Optionally, where the source hydrogen fuel heat exchanger is provided, the hydrogen fuel thermal conditioning system is configured to selectively permit a flow of the source hydrogen fuel to the source hydrogen fuel heat exchanger, and / or to selectively permit a flow of the hydrogen fuel in the fuel supply system to the source hydrogen fuel heat exchanger.

[0022] Optionally, the hydrogen fuel thermal conditioning system is configured to control a rate of heating of the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel. This may allow the hydrogen fuel that is to be transferred from the fuel supply system to the recipient system to be heated to a desired temperature, depending upon the specific recipient system or specific operating parameters of the recipient system. This may provide a more versatile hydrogen fuel thermal conditioning system than a comparable system that is unable to control a rate of heating of the hydrogen fuel in the fuel supply system.

[0023] Optionally, where the hydrogen fuel thermal conditioning system comprises the hydrogen fuel heat exchanger, the fuel supply system may comprise a flow control valve that is operable to control a rate of flow of hydrogen fuel through the first side of the hydrogen fuel heat exchanger, thereby to control a rate of heating of the hydrogen fuel in the fuel supply system. Optionally, the hydrogen fuel thermal conditioning system comprises a mixing chamber into which hydrogen fuel that has passed through the first side of the hydrogen fuel heat exchanger is received and mixed with other hydrogen fuel in the fuel supply system that has not passed through the first side of the hydrogen fuel heat exchanger, e.g., which has bypassed the first side of the hydrogen fuel heat exchanger. Optionally, the flow control valve is operable to control a rate of flow of hydrogen fuel from the hydrogen fuel heat exchanger to the mixing chamber, to control a rate of heating of hydrogen fuel in the mixing chamber.

[0024] A second aspect of the present invention provides a hydrogen fuelling system comprising the hydrogen fuel thermal conditioning system of the first aspect of the present invention. The hydrogen fuelling system may be a mobile hydrogen fuelling system.

[0025] The hydrogen fuelling system may be an aircraft hydrogen fuelling system. Optionally, the recipient system comprises a recipient hydrogen fuel tank of an aircraft. Optionally, the source system comprises a source hydrogen fuel tank of an aircraft. Optionally, the source hydrogen fuel tank is the same fuel tank as the recipient hydrogen fuel tank, where provided.

[0026] A third aspect of the present invention provides a method of thermally conditioning hydrogen fuel using a hydrogen fuel thermal conditioning system, the method comprising: receiving, at the hydrogen fuel thermal conditioning system, a source hydrogen fuel from a source system; heating hydrogen fuel in a fuel supply system of the fuel thermal conditioning system using energy from the source hydrogen fuel to provide heated hydrogen fuel; and supplying the heated hydrogen fuel from the fuel supply system to a recipient system.

[0027] It will be appreciated that method of the second aspect of the present invention may benefit from any of the advantages ascribed to the hydrogen fuel thermal conditioning system of the first aspect.

[0028] Optionally, the method is performed using the hydrogen fuel thermal conditioning system of the first aspect of the present invention. The method may comprise any of the optional functions of the hydrogen fuel thermal conditioning system of the first aspect of the present invention. Optionally, the receiving the source hydrogen fuel comprises receiving the source hydrogen fuel in the energy transfer system of the hydrogen fuel thermal conditioning system of the first aspect of the present invention. Optionally, the fuel supply system is the fuel supply system of the hydrogen fuel thermal conditioning system of the first aspect of the present invention.

[0029] Optionally, the method comprises fluidically coupling the fuel supply system to the recipient system and / or fluidically coupling the energy transfer system to the source system.

[0030] Optionally, the hydrogen fuel thermal conditioning system is configured to be selectively operable in: a first mode, in which the hydrogen fuel thermal conditioning system heats the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel; and a second mode, in which the hydrogen fuel thermal conditioning system does not heat the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel. Optionally, the method comprises selecting which of the first mode and the second mode to operate the hydrogen fuel thermal conditioning system in.

[0031] Optionally, the method comprises causing operation of the hydrogen fuel thermal conditioning system in the selected first mode or second mode. This may be by selectively permitting a flow of hydrogen fuel in the fuel supply system to the hydrogen fuel heat exchanger, where provided. This may, in turn, be by causing operation of the fuel supply isolation valve, where provided, and / or the fuel supply divertor valve, where provided.

[0032] Optionally, the method comprises converting the energy from the source hydrogen fuel into heat energy, and using the heat energy to heat the hydrogen fuel in the fuel supply system. Optionally, the method comprises causing the source hydrogen fuel to pass through the energy convertor, where provided, to convert the energy from the source hydrogen fuel into heat energy. Optionally, the method comprises using the energy convertor to provide the energy transfer fluid containing the heat energy. Optionally, the method comprises causing the heat energy to be transferred from the energy transfer fluid to the hydrogen fuel in the fuel supply system. Optionally, the method comprises causing the source hydrogen fuel and oxygen to pass through the catalyst bed, where provided. Optionally, the method comprises providing heated steam as the energy transfer fluid.

[0033] A fourth aspect of the present invention provides a controller configured to cause a hydrogen fuel thermal conditioning system to perform the method of the third aspect of the present invention. The hydrogen fuel thermal conditioning system may be the hydrogen fuel thermal conditioning system of the first aspect of the present invention. It will be appreciated that the controller of the fourth aspect of the present invention may benefit from any of the advantages ascribed to the first, second or third aspects of the present invention.

[0034] Optional features of any one of the aspects of the present invention may be applied equally to any other one of the aspects of the present invention, where appropriate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0036] Figure 1 shows a schematic view of a mobile fueling station and an aircraft;

[0037] Figure 2 shows a schematic view of the mobile fueling station of Figure 1.

[0038] Figure 3 shows a flow diagram of an example method of thermally conditioning hydrogen fuel; and

[0039] Figure 4 shows a flow diagram of a further example method of thermally conditioning hydrogen fuel. DETAILED DESCRIPTION

[0040] Figure 1 shows a hydrogen fuel thermal conditioning system in the form of a mobile fueling station 1 that, as will be described below, is removably connected to, and configured to provide hydrogen fuel to, an aircraft fuel system 20 of an aircraft 2. The mobile fueling station 1 comprises an energy transfer system (in the form of a heating system 200), a fuel supply system 100 and a locomotion element 10. The mobile fueling station 1 also comprises a fuel outlet 11 fluidically connected by a flexible hose to the fuel supply system 100, and a fuel inlet 12 fluidically connected by a flexible hose to the heating system 200. The aircraft fuel system 20 of the aircraft 2 comprises an aircraft fuel tank 23, an aircraft inlet 21 and an aircraft outlet 22. The aircraft inlet 21 and aircraft outlet 22 are each fluidically connected to the aircraft fuel tank 23 by associated pipework. The fuel outlet 11 of the mobile fueling station 1 is removably fluidically connected to the aircraft inlet 21 using a clamp mechanism (not shown). The fuel inlet 12 of the mobile fueling station 1 is similarly removably fluidically connected to the aircraft outlet 22 using a clamp mechanism (not shown).

[0041] Broadly speaking, and as will be described in more detail below, the fuel supply system 100 is designed and arranged to store hydrogen fuel in a cryogenic liquid state, and to supply the hydrogen fuel to the aircraft fuel tank 23 via the fuel outlet 11 and the aircraft inlet 21. The heating system 200 is designed and arranged to receive gaseous hydrogen fuel from the aircraft fuel tank 23, which is passed as “return” hydrogen fuel to the mobile fuel system 1 via the aircraft outlet 22 and the fuel inlet 12 as pressure in the aircraft fuel tank 23 increases. The return hydrogen fuel is thus, in this example, “source” hydrogen fuel for the energy transfer system of the hydrogen fuel thermal conditioning system.

[0042] The heating system 200, as will be described in more detail below, causes a reaction between the return hydrogen fuel received from the aircraft fuel tank 23 and oxygen-containing air to produce heat and steam. Again, as will be described in more detail below, in a first mode of operation of the mobile fueling station 1, the heated steam provided by the heating system 200 is used to heat hydrogen fuel in the fuel supply system 100 that is to be provided to the aircraft fuel tank 23. This provides an efficient arrangement whereby gaseous hydrogen fuel from the aircraft fuel tank 23, which might otherwise be combusted and / or vented to the atmosphere during fueling of the aircraft fuel tank 23, is instead used to generate heat to heat the hydrogen fuel that is to be supplied to the aircraft fuel tank 23. This also provides steam as a byproduct, which may be collected (as described below) or released into the atmosphere, improving safety of the mobile fueling station compared to a station that vents and / or combusts the return hydrogen fuel.

[0043] The locomotion element 10 comprises wheels (not shown) that are operable to move the mobile fueling station 1. In the illustrated example, the wheels are operated to move the mobile fueling station 1 towards the aircraft 2 after the aircraft 2 has landed at an airport or other location, and to move the mobile fueling station 1 away from the aircraft 2 once hydrogen fuel has been supplied to the aircraft fuel system 20.

[0044] It will be appreciated that, whilst the present example is described in relation to the mobile fueling station 1, this is an example only, and components of this example, such as the heating system 200, may be applied to any other suitable fuel supply system that is configured to supply hydrogen fuel to a recipient system. For instance, a static fuel conditioning system may be provided, and the heating system 200 may be configured to heat fuel in the static fuel conditioning system using hydrogen fuel from any suitable source system. The source system may the same system as a recipient system to which the static fuel conditioning system is configured to supply fuel (as in the illustrated example) or may be another system. In various examples, such a source system and / or recipient system need not be a part of an aircraft. Other arrangements will be evident to the skilled person in view the specific examples in the following description.

[0045] Turning now to Figure 2, the mobile fueling station 1 is shown and described in more detail. The locomotion element 10 is omitted from Figure 2, for visual clarity. The mobile fueling station 1 comprises a controller 50. The heating system 200 comprises an air inlet 210, an air compressor220, an air flow control valve 230, a catalyst bed 240, a fuel supply heat exchanger 250 and a collection tank 260. The fuel supply heat exchanger 250 comprises a first side 251 and a second side 252, and is arranged to transfer heat from fluid flowing through the first side 251 and fluid flowing through the second side 252 in use. The air inlet 210, the air compressor 220, the air flow control valve 230, and the catalyst bed 240 are fluidically connected in series, in that order, by associated pipework. The catalyst bed 240 is fluidically connected by pipework to the fuel inlet 12 so as to receive return hydrogen fuel from the fuel inlet 12. The catalyst bed 240 is also fluidically connected in series by pipework to the first side 251 of the fuel supply heat exchanger 250 and the collection tank 260, in that order. The catalyst bed 240 comprises platinum as a catalyst, the platinum dispersed on an aluminium oxide (A1O3) ceramic matrix. It is, however, possible to use other catalysts (such as palladium) and other supporting structures for the catalyst.

[0046] The fuel supply system 100 comprises a storage tank 110, a fuel pump 120, a fuel storage heat exchanger 130, a divertor valve 140, a heat flow control valve 160, a mixing chamber 150, a bypass conduit 180, and a supply flow control valve 170. The storage tank 110, fuel pump 120 and fuel storage heat exchanger 130 are fluidically connected by pipework in a fluid loop. The fluid loop permits recirculation of hydrogen fuel from the storage tank 110 back to the storage tank 110 via the heat exchanger 130. In particular, the fuel supply system 100 is able, using a valve arrangement (not shown) to cause hydrogen fuel pumped by the fuel pump 120 to pass towards the heat exchanger 130 in the fluid loop and towards the divertor valve 140 at different flow rates. This allows the fuel pump 120 to pump fuel from the hydrogen fuel tank at a fixed mass flow rate and pressure. The fluid loop then enables a mass flow rate and pressure of hydrogen fuel delivered to the fuel outlet 11 to be managed by passing some of the hydrogen fuel pumped by the fuel pump 120 back to the storage tank 110 via the heat exchanger 130. Passing the hydrogen fuel through the heat exchanger 130 also permits heating of the hydrogen fuel in the storage tank 110, which can further heat the fuel in the fuel storage system 100.

[0047] The divertor valve 140 is a three-way valve comprising a divertor inlet and first and second divertor outlets (not labelled in Figure 2). The divertor inlet is fluidically connected by pipework to the fuel pump 120, the first divertor outlet is fluidically connected by pipework to the mixing chamber 150 via the second side 252 of the fuel supply heat exchanger 250 and the heat flow control valve 160 (in that order), and the second divertor outlet is fluidically connected by pipework to the mixing chamber 150 via the bypass conduit 180, which bypasses the second side 252 of the fuel supply heat exchanger 250. The supply flow control valve 170 is fluidically connected by pipework between the mixing chamber 150 and the fuel outlet 11. The divertor valve 140 is configurable selectively in: a first configuration, in which the divertor inlet is fluidically connected to each of the first and second divertor outlets; and a second configuration, in which the divertor inlet is fluidically connected only to the second divertor outlet.

[0048] The controller 50 is communicatively coupled to the air compressor 220, the air flow control valve 230, the fuel pump 120, the divertor valve 140, the heat flow control valve 160, and the supply flow control valve 170. In use, the controller 50 is programmed to cause operation of the mobile fuel system 1 selectively in a first mode of operation and a second mode of operation. In the first mode of operation, the controller 50 is configured to cause operation of the fuel pump 120, the divertor valve 140 and the heat flow control valve 160 to pump hydrogen fuel from the storage tank 110 to the mixing chamber 150 via the second side 252 of the fuel supply heat exchanger 250. This is by the controller 50 causing the divertor valve 140 to be configured in the first configuration. In the second mode of operation, the controller 50 is configured to cause operation of the fuel pump 120 and the divertor valve 140 to pump hydrogen fuel from the storage tank 110 to the mixing chamber 150 via the bypass conduit 180, i.e., without also flowing through the second side 252 of the fuel supply heat exchanger 250. This is by the controller 50 causing the divertor valve 140 to be configured in the second configuration. In each of the first and second modes of operation, the controller 50 is configured to cause opening of the supply flow control valve 170 to cause the fuel that is supplied to the mixing chamber 150 to be passed to the fuel outlet 11, and subsequently to the aircraft fuel tank 23 via the aircraft inlet 21 shown in Figure 1.

[0049] The controller 50, in each of the first and second modes of operation, is also configured to cause operation of the air compressor 220 and the air flow control valve 230 to cause an oxygen-containing air stream to pass from the air inlet 210 through the catalyst bed 240. At the same time, pressure in the aircraft fuel tank 23 causes the return hydrogen fuel to be urged from the aircraft fuel tank 23 and through the catalyst bed 240 via the fuel inlet 12. The return hydrogen fuel is passed through the catalyst bed 240 at the same time as the air stream, which causes the return hydrogen fuel to react with the oxygen in the air stream. The platinum in the catalyst bed 240 functions as a catalyst for the rection. The reaction in the catalyst bed 240 generates heat and produces water in the form of heated steam. The heated steam is caused to pass through the first side 251 of the fuel supply heat exchanger 250 and is subsequently collected in the collection tank 260.

[0050] It will be appreciated that, in the first mode of operation, the hydrogen fuel in the fuel supply system 100 that is caused to pass through the second side 252 of the fuel supply heat exchanger 250 is heated by the heated steam that is caused to pass through the first side 251 of the fuel supply heat exchanger 250. The controller 50 in that case is configured to cause operation of the heat flow control valve 160 to control a rate at which the heated hydrogen fuel from the second side 252 of the fuel supply heat exchanger 250 is passed to the mixing chamber 150 to be mixed with cooler hydrogen fuel received directly from the fuel pump 120 and divertor valve 140. In this way, the controller 50 is able to control a temperature of the hydrogen fuel in the mixing chamber 150, and thus a temperature of the hydrogen fuel supplied to the fuel outlet 11 and the aircraft fuel tank 23.

[0051] In the second mode of operation, the hydrogen fuel in the fuel supply system 100 is not passed through the second side 252 of the fuel supply heat exchanger 250, and so there is no heat transfer between the heated steam in the first side 251 of the heat exchanger and hydrogen fuel in the fuel supply system 100. In this way, the controller 50 is selectively able to cause hydrogen fuel to be passed from the storage tank 110 to the fuel outlet 11, and on to the aircraft fuel tank 23, without heating the hydrogen fuel using energy from the return hydrogen fuel.

[0052] Figure 3 shows an example method 400 of thermally conditioning hydrogen fuel. In this example, the mobile fueling station 1 is configured to perform the method 400. Specifically, the controller 50 is configured to cause operation of the mobile fueling station 1 in any suitable way as described above to cause the mobile fueling station 1 to perform the method 400. It will be appreciated that, in other examples, the method 400 may be performed by any other suitable system.

[0053] The method 400 comprises receiving 410 return hydrogen fuel from the aircraft fuel system 23. The return hydrogen fuel is, in this case, received by the heating system 200. The method 400 also comprises heating 420 hydrogen fuel in the fuel supply system 100 using energy from the return hydrogen fuel received, and supplying 430 the heated hydrogen fuel from the fuel supply system 100 to the aircraft fuel system 20.

[0054] Figure 4 shows a further example method 500 of thermally conditioning hydrogen fuel. The method 500 includes each of the actions 410, 420, 430 of the method labelled 400, which are each labelled with reference numerals incremented by 100. The heating 520 the hydrogen fuel in the fuel supply system 100 is by the method 500 comprising causing 521 the return hydrogen fuel and oxy gen-containing air to pass through the catalyst bed 240 to generate heated steam. The method 500 then comprises causing 522 the heated steam to pass through the first side 251 of the fuel supply heat exchanger 250. The method 500 also comprises causing 523 operation of the mobile fueling system 1 selectively in the first mode of operation or the second mode of operation. This causes hydrogen fuel in the fuel supply system 100 to, respectively, pass through the second side 252 of the fuel supply heat exchanger 250, or to bypass the second side 252 of the fuel supply heat exchanger 250. This causes, in the first mode of operation, heat to be transferred from the heated steam in the first side 251 of the fuel supply heat exchanger 250 to the hydrogen fuel in the second side 252 of the fuel supply heat exchanger 250. In the first mode of operation, the method 500 comprises causing 524 operation of the heat flow control valve 160 to control an amount of the hydrogen fuel passed from the second side 252 of the fuel supply heat exchanger 250 to the mixing chamber 150. This is to control a temperature of hydrogen fuel in the mixing chamber 150, which is subsequently delivered to the aircraft fuel tank 23. The supplying 530 the hydrogen fuel from the fuel supply system 100 to the aircraft fuel tank 23 is by the method 500 comprising causing 531 operation of the supply flow control valve 170 to control a flow rate and / or pressure of the hydrogen fuel supplied to the aircraft fuel tank 23.

[0055] It will be appreciated that, in various examples, either of the above-described methods 400, 500 may comprise any of the functions that the controller 50 described above causes the mobile fueling station 1 to perform. For instance, the methods 400, 500 may, in various examples, comprise causing operation of the fuel pump 120, the divertor valve 140, the heat flow control valve 160, the supply flow control valve 170, the air compressor 220, and / or the air flow control valve 230 as required to cause the mobile fuel system 1 to perform any of the functions described above.

[0056] The controller 50 in the present example, though not shown in the Figures, comprises a non-transitory computer-readable storage medium storing instructions that, when executed by a processor (also not shown) of the controller 50, causes the controller to cause operation of the mobile fuel station 1 to cause the mobile fuel station 1 to performs either of the methods 400, 500 described above.

[0057] Alternatives and modifications to the above-described examples, within the scope of the appended claims, will be evident to the skilled person. For instance, whilst the mobile fueling station 1 described above comprises wheels that are operated to move the mobile fueling station 1, in other examples, the mobile fueling station 1 may be towed and the wheels may be unpowered. In other examples, the locomotion element 40 may comprise other than wheels, such as tracks or slides, or the fueling station 1 may be immobile.

[0058] The divertor valve 140 described above is configured in the first configuration to pass hydrogen fuel towards the second side 252 of the fuel supply heat exchanger 250 and the mixing chamber 150 simultaneously. In other examples, in the first configuration, the divertor inlet is fluidically connected to only the first divertor outlet, and in the second configuration, the divertor inlet is fluidically connected only to the second divertor outlet. As such, hydrogen fuel may only be provided from the divertor valve 140 to the second side of the heat exchanger 250, and not also to the mixing chamber 150, in the first mode of operation. In some such examples, the hydrogen fuel from the heat flow control valve 160 may be mixed with hydrogen fuel already present in the mixing chamber 150. In other such examples, the mixing chamber 150 and / or supply flow control valve 170 may be omitted.

[0059] In one implementation, provided by way of illustrative example only, (saturated) gaseous hydrogen fuel flows from the aircraft fuel tank 23 to the catalyst bed 240 at a flow rate of 100 g / s and a pressure of 11 bar. The gaseous hydrogen fuel flowing to the catalyst bed 240 therefore has a potential energy of 12 MJ / s. Taking, for example, an efficiency of the catalyst bed 240 of 20%, there is 2.4 MW of available thermal power in the return hydrogen fuel. The resulting water vapour / steam is produced at 0.9 kg / s, which is heated from the reaction of hydrogen with air in the catalyst bed 240 to provide superheated steam. The return hydrogen fuel thus provides sufficient energy to heat this steam to a “medium pressure” steam at 5 bar, 350 degrees Celsius, which in many cases would be more than needed to heat the hydrogen fuel in the fuel storage system 100 to a required temperature. Any remaining heat caused by the reaction in the catalyst bed 240 may be rejected to the atmosphere through, for example, a cooling heat exchanger (not shown). The cooling heat exchanger may surround the catalyst bed 240, or otherwise cause heat to be transferred away from the catalyst bed 240. In summary, in this example, the quantity of heat generated by the aircraft fuel system 20, using return hydrogen fuel from the aircraft fuel tank 23, is more than is required to heat hydrogen fuel to be supplied to the aircraft fuel tank 23.

[0060] It is to be noted that the term “or” as used herein is to be interpreted to mean “and / or”, unless expressly stated otherwise.

Claims

1. A hydrogen fuel thermal conditioning system, comprising:a fuel supply system comprising a tank configured to store hydrogen fuel and an outlet fluidically connectable to a recipient system, the fuel supply system configured to transfer hydrogen fuel from the tank to the recipient system via the outlet; andan energy transfer system comprising an inlet fluidically connectable to a source system, the energy transfer system configured to receive source hydrogen fuel from the source system via the inlet, and to use energy from the source hydrogen fuel to heat the hydrogen fuel in the fuel supply system.

2. The hydrogen fuel thermal conditioning system of claim 1, configured to be selectively operable in:a first mode, in which the hydrogen fuel thermal conditioning system heats the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel; anda second mode, in which the hydrogen fuel thermal conditioning system does not heat the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel.

3. The hydrogen fuel thermal conditioning system of claim 1 or claim 2, wherein the energy transfer system comprises an energy converter configured to convert the energy from the source hydrogen fuel into heat energy, and to use the heat energy to heat the hydrogen fuel in the fuel supply system.

4. The hydrogen fuel thermal conditioning system of claim 3, wherein the energy converter comprises a catalyst bed in which the source hydrogen fuel is able to be reacted with a reactant to produce the heat energy.

5. The hydrogen fuel thermal conditioning system of claim 3 or claim 4, wherein the energy convertor is configured to provide an energy transfer fluid containing the heat energy.

6. The hydrogen fuel thermal conditioning system of claim 5, wherein the energy transfer system comprises a fuel supply heat exchanger configured to transfer the heat energy in the energy transfer fluid to the hydrogen fuel in the fuel supply system.

7. The hydrogen fuel thermal conditioning system of claim 6, configured to selectively permit a flow of hydrogen fuel in the fuel supply system to the fuel supply heat exchanger.

9. The hydrogen fuel thermal conditioning system of any one of claims 1 to 8, configured to control a rate of heating of the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel.

10. A hydrogen fuelling system comprising the hydrogen fuel thermal conditioning system of any one of claims 1 to 9.

11. A method of thermally conditioning hydrogen fuel using a hydrogen fuel thermal conditioning system, the method comprising:receiving, at the hydrogen fuel thermal conditioning system, a source hydrogen fuel from a source system;heating hydrogen fuel in a fuel supply system of the fuel thermal conditioning system using energy from the source hydrogen fuel to provide heated hydrogen fuel; and supplying the heated hydrogen fuel from the fuel supply system to a recipient system.

12. The method of claim 11, wherein the hydrogen fuel thermal conditioning system is configured to be selectively operable in:a first mode, in which the hydrogen fuel thermal conditioning system heats the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel; anda second mode, in which the hydrogen fuel thermal conditioning system does not heat the hydrogen fuel in the fuel supply system using the energy from the source hydrogen fuel; andwherein the method comprises selecting which of the first mode and the second mode to operate the hydrogen fuel thermal conditioning system in.

13. The method of claim 11 or claim 12, comprising converting the energy from the source hydrogen fuel into heat energy, and using the heat energy to heat the hydrogen fuel in the fuel supply system.

14. A controller configured to cause a hydrogen fuel thermal conditioning system to perform the method of any one of claims 11 to 13.

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