GB2546299A

GB2546299A - Fuel cartridge fill level sensing

Info

Publication number: GB2546299A
Application number: GB1600731.2A
Authority: GB
Inventors: Edgar David
Original assignee: Intelligent Energy Ltd
Current assignee: Intelligent Energy Ltd
Priority date: 2016-01-14
Filing date: 2016-01-14
Publication date: 2017-07-19
Also published as: GB201600731D0

Abstract

A fuel supply 1 for a fuel cell (33, fig 3) comprises a reaction chamber 2 configured to generate fluid fuel from a fuel source 10. A temperature sensor 8 is configured to detect a thermal profile of the reaction chamber 2 and to determine a remaining fuel capacity of the fuel supply 1 from the thermal profile. The fuel supply 1 may include a second reactant and/or catalytic material 11 which interacts with the fuel source 10 to produce the fuel, e.g. hydrogen. The thermal profile may be a spatial thermal profile of the reaction chamber 2 which is indicative of a location of a reaction within the reaction chamber that varies as a function of fuel source 10 remaining unspent. A fill level of the cartridge may therefore be ascertained without requiring pressure sensing or flow sensing within the cartridge. Further aspects relate to a fuel consuming device in which the amount of remaining fuel is determined from the measurement of the temperature sensor 8, and a related method, and also a reactor and method in which the temperature sensor 8 measures an endothermic or exothermic reaction taking place within the reactor, in order to determine the amount of reactant remaining.

Description

FUEL CARTRIDGE FILL LiVEL SENSING

The present invention relates to fuel supplies and in particular, though not exclusively, to cartridge-type fuei supplies that can fee used to supply fluid fuei to electrochemical fuel cells.

Fuei ceils are now widely used for the generation of electricity from a fluid fuel source. 'Various types of fuel source are known: for supplying fluid fuels to fuel ceils, such as hydrogen sources or hydrocarbon sources For example, various types of hydrogen sources are known* such as those configured: to generate gaseous hydrogen by a hydrolysis reaction, a thermolysis reaction or a desorption process.

One: convenient fuei source erfangernent comprises a reaction chamber filled with a suitable first reactant such as sodium feorohydride and a reservoir of a suitable second reactant, such as water. When hydrogen is required, water can be released from the reservoir into the reaction chamber to initiate a hydro lysis reaction in which hydrogen is released (e.g. NaBKs T 2 HsO NaBGs + # Ffe|,·

It is desirable to provide a mechanism for determining the remaining iM supply available from a fuei supply. Providing an accurate indication of fuel supply remaining can fee a difficult task, ©specially where the fuel, such:as hydrogen, is feeing generated on demand from precursor components such as a feorohydride and water, A pressure sensor and / or flow meter may be used to monitor pressure within a reaction chamber and / or flow rates from the reaction chamber and to use the measured data oyer time to compute a likely remaining fuei capacity of the cartridge. However, the use of pressure sensors and flow meters may hot always be optimal given cost and design oonstfaints, ft would be desirable to provide alternative techniques to those relying on pressure and / or flow sensors to determine remaining fuei capacity of a fuel source.

According to one aspect, the present invention provides a fuei supply for a fuel ceil, comprising a reaction chamber configured to generate fluid fuei from a fuel source; a temperature sensor configured to detect a thermal profile of the reaction chamber and to determine: a remaining fuei capacity of the fuel supply from the thermal profile,;

The thermal profile detected by the temperature sensor may comprise a spatial thermal profile of the reaction chamber. The spatial thermal profile may be indicative of a location cf a reaction within the reaction chamber that varies as a function of fuel source remaining unspent. The: temperature: sensor may be configured to detect a position of a temperature gradient within the reaction chamber, and to determine remaining fuei capacity from the position of the temperature gradient. The thermal profile detected by the temperature sensor may comprise a temporal thermal profile of the reaction chamber. The temporal thermal profile may be indicative of an extent of reaction that has occurred within the reaction chamber over time. The sensor may be configured to determine remaining fuel Capacity based on the temporal thermal profile. The temperature sensor may comprise a thermal imaging device. The temperature sensor may comprise an array of thermal sensors disposed adjacent to the reaction chamber. The temperature sensor may comprise a strip of temperature-sensitive materia! disposed adjacent to the reaction chamber.

The fuei supply may include: an orientation sensor configured to determine an orientation bf the fuei supply; and a processor configured to determine remaining fuel capacity based on the spatial thermal profile and the orientation of the fuel supply. The spatial thermal profile of the reaction chamber delected by the temperature sensor may indicate a fuei source / fuel gas boundary within: the reaction chamber. The reaction chamber may be charged with a first r eactant material and the fuel supply may Include a reservoir of second reactant or catalyst configured to be introduced into the reactant chamber to generate the fluid fuel. The fuel supply may comprise a removable fuel cartridge for use with a fuel ceil powered dewoe.

According to another aspect, the present invention provides a fuei consuming device comprising: a receptacle configured to receive a fuel supply cartridge; one of more temperature sensors disposed within the receptacle configured to detect a theitriai profte of the fuel supply cartridge when it is installed in the receptacle, the temperature sensor being ddOfigured; to determine a remaining fuel capacity of the fuel supply from the thermal profile.

The fuel consuming device may further comprise: a fuel cell; and a fluid fuel conduit coupling the receptacle and the fuel cell, the fuel ceil may be configured to generate electrical power from fluid fuel supplied by a fuel supply cartridge when installed within the receptacle, via the fluid fuel conduit. iaifi^heir:':g^pecst. the present invention provides a method of determining a remaining fuel capacity of a fuel supply, comprising the steps pi

Initiatingareactionin a: reaction: chamber to generate fluid fuel from a fuel source; using a temperature sensor to detect a thermal profile of the reaction chamber containing the fuel source; and determining a remaining fuei capacity of the fuel supply from the thermal profile

The method may further Include using the detected thermal profile to determine a spatial extent of the reaction. The method may further include using the detected thermal profile to determine a temporal extent of the reaction, The method may further include using the detected thermal profile to detect the position of a fuei source / fuel gas boundary within the reaction chamber,

According to another aspect, the present invention provides a reactor, comprising: a reaction chamber having at least one maetahicohfained therein, which reactant is configured to generate at least one produef in an ehddthermic or exothermic process; a temperature sensor conhgumd te dets^t e thermal profile of the reaction chamber and to thereby determine an extent of the me^ldn that has taken place within the reaction chamber from the measured thermal profile.

The reactor may he: a fuel supply. The maptaoi may be a fuei source. The product may be a fluid fuel.

According to another aspect, the present invention provides a method of monitoring a reaction In which at ieast one reactant generates at least one product in an endothermic or exothermic process, the method comprising: using a temperature sensor to defect a thermal profile of the reactant and / or a confinement vessel thereof; determining an extent of the reaction that has taken piace in the reactant from the measured thermal profile; determining from said extent; an amount of reactant remaining.

The method may further comprise determining an amount of product still available for generation from said amount of reactant remaining. The reactant may be a fuel source and the product may be a fluid fuel.

Embodiments of the present invention will now be described by way of example and with; reference to the accompanying drawings in which;

Figure 1 shows a schematic diagram of a fuel supply cartridge with thermal sensing;

Figure 2 shows thermal images otthe cartridge of figure 1 during use;

Figure 3 shows a schematic side view of a fuel consuming device having a receptacle for installation of the fuel supply cartridge.

Figure 1 shows a fuel supply cartridge 1 (or other fuel supply unit) suitable for supplying a fluid fuel, such as hydrogen, from a fuel source 10, The cartridge 1 comprises a reaction; chamber 2 containing an amount of the fuel source 10 from which the ted fuel such as gaseous hydrogen, may be generated and released from the cartridge via an outlet 3, The outlet 3 may include various control mechanisms such PS: i vii^e 4 fob mainfairiing a fiyid tight seal to the outlet 3 when the cartridge is not connected to a fuel-consuming device dr when fluid fuel is otherwise not to be released; a safety pressure relief valve (not shownt; and any other flow control mechanisms or infrastructure that may be required or desirable (also not shown).

The fuel source 10 may be provided as a irsf reactant, and the fuel supply cartridge 1 may also include a second chamber 5 for storing a second reactant 11 or a catalyst materia! or a combination of both. A control mechanism 6 may be provided which is configured to control delivery of the second reactant I t into the reaction chamber 2, or to control delivery of catalyst material into the reaction cfiamber 2, or a combination of both. Upon reaction of the fuel source 10 (e.g. by mixing with the second reactant 11 or by the presence of a catalyst), pressurised fluid fuel may be generated within a head space 12 or plenum of the reaction chamber 2.

Many different types of first reactant 10 / second reactant 11 / catalyst material combination may be envisaged which are felevant to the fuel supply cartridge 1, fee a liquid and the catalyst or second reactant couid also fee in liquid form and introduced into the reaction chamber on demand when the pressure of fluid fuel in the head spade 12fai]e ieiee? a threshdid. Automated mechanisms may be used to maintain availability of an appropriate amount of second reactant or catalyst within the reaction chamber to sustain a desired level of fluid fuel pressure in the head space 12. Suitable automated; mechanisms for delivery of the second reactant or of the catalystidiia reaction chamiberiafe isneraily known in the prior art.

The catalyst material could be a solid material graddaiiy Introduced into the reaction chamber using any suitable driving or pumping mechanism.

In another arrangement, the fuel source fb cefeid:; be in a powdered form and the second reactant 11 couid be a liquid injected into the reaction chamber.

Disposed along the side wail 7 of the reaction chamber 2 is a temperature sensor 8 which is configured to detect a thermal profile of the: reaction chamber, in one arrangement, the temperature sensor 8 comprises an array of thermal Censors emending along a longitudinal axis of the reaction chamber 2. Multiple sensors I could be provided at different positions around the reaction chamber, such as at two or more circumferential positions around the cylindrical chamber as shown in figure I, A second sensor array: couid be configured to extend in a different direction than the first sensor array, e.g. orthogonal thereto, in an alternative arrangement, the temperature sensor 8 could be a strip of temperature-sensitive material capable of being; sampled: at multipie points .along its ien|th> ilg, a temperature grid sensor.

In another aiternative arrangement, the temperature sensorS could comprise one or mors thermal imaging devices disposed adjacent to the reaction chamber 2 each capable of generating a spatial temperature profile of at least a respective portion of the walls of the reaction chamber 2. Suitable imaging devices may comprise semiconductor devices incorporating infrared detectors.

In another alternative arrangement, the temperature sensor 8 could cam prise one or more thermal Imaging devices located at a position remote from the reaction chamber and/or remote from the fuel supply cartridge, e.g. some ncn-adiacent position to the reaction chamber and/or the fuel supply cartridge. In arrangements to be discussed below, the one or more thermal imaging devices could be disposed on dr in a device that is separate from; the fuel supply cartridge, e.g, a device in or on which the cartridge is Installed or with which it is associated.

In the arrangement as depicted In figure 1, when a reaction is initiated in the fuei source 10 within the reaction chamber 2 to generate fluid fuel in the head space 12, the temperature of the fuel source 10 will rise and create a temperature -#^ϋί?5Μ feelween the fuel source material 10 and the gaseous fuel in the head space 12,

As seen in the exemplary images shown in figure 2, this temperature differential may manifest Itself as a temperature gradient 20 between a first temperature region 21 corresponding;to Ihe reacting fuel source 10 and a second, lower, temperature region 22 corresponding; to the gaseous fuel in the head space 12. 1 Mil be seen that the position of the temperature gradient 20 moves as a function ofthe remaining fuel capacity indicated by the extent ofthe fuel source 10. This te indicated fey a height Hi of the temperature gradient 20;relative to the outlet 3 in the first image shown in figure 2a and the height H2 of the temperature gradient 20 shown In figure 2c taken after approximately 2 hours’ use. It can be seen from the images that the absolute temperature can vary (34.8 °C in figure 2a and 40.8 °C In figure 2c) but this does; hot: matter slnc^ the position of the temperature gradient 20 is indicative of the remaining feel capacity of the fuel source 10 since it relates to the level of fuel source TO within the reaction chamber 2. in this example, the temperature gradient is indicative Of a fuel source / fuel gas boundary within the reaction chamber 2 A suitable processor 15 (which may be a digital processor or ahalc|pe / digl&f circuit, for example) may be provided to receive temperature data from the temperature sensor 8 and thereby determine a spatial thermal profile of the reaction chamber 2> In a relatively simple form, as described above, the spatial thermal profile need only enable the determination of the position of a temperature gradient 20 (e.g. step changepndicafive of the fuel source / fuel gas boundary. it can also be seen that the spatial thermal profile is indicative of a location of a reaction within the reabtiort ftartber 21 compared to the cooler region 22, and the location of the reaction, e g its spatial extent, varies as a function of the fuel source remaining unspent.

More sophisticated algorithms may be deployed. For example, the processor 15 may maintain a temporal thermal profile, e.g. by recording a spatial thermal profile over time. Such an approach may allow time averaging and the reduction of noise in the measurements to provide a more accurate assessment of fuel use and i or to deduce a rate of fuel use.

In examples where the fuel source 10 is in liquid or powder form, the spatial profile may vary according fo the ® of the cadfidgi In Ρρρ* e.,g. with the head space 12 rising to the highest point of the cartridge. Therefore, the disposition of the temperature sensor(s) may be adapted to enable measurement of the location of the fuel source / fuel gas boundary (at temperature gradient position 20)in different orientations. The cartridge 1 may include an orientation sensor coupied to, or iridOrporaied witriih, the pfbdessor 1I to provide an indication of cartridge orientation:, the processor 15 may then be configured to determine the remaining fuel capacity based on the spatial thermal profile and the orientation of the cartridge 1, The orientation sensor may be external: to the cartridge and could be provided by another piece of equipment in Tdhich the cartridge 1 is being used. The orientation may alternatively be deduced from the spatial thermal profile itself, e.g. if the temperature sensor(s) are capable of determining a temperature gradient position at different angles relative to the cartridge axis.

Many other configurations of cartridge or, more generally, fuel supply, may be envisaged which use a temperature sensor 8 to detect a thermal profile of the reaction chamber to determine a remaining fuel capacity.

For example, the reaction chamber may be a chamber which varies in size as reactant maierM is delivered to it and / or reacted material is expelled from it, e.g. using beiiows / piston type arrangements Known In some fuelcartridges, The thermal profile can still be monitored to provide an indication of the spatial extent Of the reaction chamber and / or the thermal history of the reaction chamber, either or both of 'which profiles may be used

Is determine the amount of fuel remaining. The temporal thermal profile may be integrated over time to determine an amount of fuel source which has been spent.

The reaction chamber may comprise a dutiable vessel for containment: of the fuel source and the generated fluid fuel. The vessel may have thermally insuiatlve properties in which case the vessel may include one or more portions of material (e.g. a strip of material) of greater thermal conductivity: which can provide improved thermal transmission to any externai temperature sensor. For example, such a strip of relatively thermally conductive material could be ppslfioned under or adjacent to the temperature sensor 8. Alternatively, such portion or portions of relatively thermally; conductive material could be disposed within the field of view of a thermal imaging device acting as the temperature sensor. Use of such a thermally conductive portion of the reaction chamber vessel may improve the ability to monitor a temperature gradient Or temperature changes within the vessel which might otherwise be masked by a thermally Insulating vessel.

The principle of using temperature sensing to detect a thermal profile of the reaction Chamber and to determine a remaining fuel capacity therefrom may be deployed in various cartridge chemistries.

This may include any fuel supply in which the position of a thermal gradient or boundary between two different temperature: regions may be indicative of an amount of fuel remaining. Alternatively, the spatial extent of a temperature gradient may be indicative of a ratio of spent to unspent fuel in the fuel source, e,g, where the spent and unspent fuel Is distributed unevenly throughout a reaction chamber according to a rate of reaction or a directionaiity of a reaction, e.g. where there is diffusion of a second reactant or catalyst through a volume of first reactant. Such an approach may be applicable to solid reactants where a clear boundary between a fuel source and: a head space or plenum containing fluid fuel may not be clearly defined. in another arrangement, a thermal profile as a function of time may be used to deduce an amount of fuel supply remaining. For example, if the reaction generating fluid fuei from a fuel source creates a thermal gradient within the cartridge, the extent of this thermal gradient: may be integrated over time to generate a measure of the extent of reaction that has occurred during the lifetime of the cartridge, Where the reaction stops and starts, allowances may be made for natural cooiing of the cartridge contents after a reaction has temporarily ceased, By men So ring a temperature gradient generated fey the reacts ng fuel source, it may1 fee possifele to eliminate the effects of variation in ambient temperature affecting the entire cartridge. in another arrangement, the temperature sensing may be used to monitor the extent of an endothermic process or reaction taking place within a reaction chamber. For example, in a fuel supply cartridge relying on a thermal decomposition process, the thermal decomposition may fee initiated fey a localised heating element within a reaction chamber, the decomposition process: then being an endothermic process. By monitoring the temperature and time profile of a reaction chamber, it may fee possible to determine an extent of the thermal decomposition process and thereby determine a remaining fuel capacity of the fuel supply from the measured thermal profile. An example of such a thermal decomposition process Is the production of hydrogen fey decomposition of ammonia borane or alane {AlH?,}. For example, aiane is stable at room temperature but thermally decomposes at 110-180 *C to yield aluminium and hydrogen, the decomposition process being limited by its endothermic nature.

In another arrangement, the temperature sensing may be of a hydrogen: desorption process, in which hydrogen previously absorbed onto a suitable substrate in a reaction chamber is desorbed on demand, The desorption process Is endothermic and thus monitoring the thermal profile of the reaction chamber may provide an Indication of the extent of cooling of the substrate consequent on the desorption, and thereby enifefe the determination of a remaining fuel capacity, in this context, the expression "reaction chamber" is intended to encompass a chamber in which the reaction of the fuel source to failing chamber pressure is for fluid fuel to be desorbed from the substrate,

More generally, the temperature sensing can be adopted to monitor any suitable reaction that takes place, where the reaction is capable of creating a measureabie thermal gradient across the cartrldgej the reaction chamber and / or the device in which the cartridge may be housed. For a fuel source starting from cpldi with all features at the same e.g ambient temperature, the temperature sensor may be adapted to monitor how the temperature profile changes during start up, the temperature gradient (e.g. maximal temperature differehee achieved across the measured part(s)} and then use additional information (e.g. calibration data j to determine a rafe of reaction, a duration of reaction or any other quantity that can be used deduce a remaining fuel capacity of the fuel supply.

The fuel; cartridge or other fuel supply uni may be used to provide hydrogen: or other fuel to a fuel ceil powered device. The: fuel cartridge or other fuel supply unit may be a removable unit for use within a fuel ceil powered: device.

Where the fuel cartridge or other fuel supply uni is configured for use within a separate device, the temperature sensor 8 and possibly also the processor 15 fundionaiity could be integrated Into the separate device:, into which the fuel cartridge is installed, in this way. the temperature sensor and processor functionality can be separated from, for example, a disposable fuel cartridge, and placed into a non-disposabie part of the system,

The fuei cartridge or other fuel supply unit may be rechargeable, e g. by replenishment of the fuei source within the reaction chamber. The fuel cartridge or other fuel supply unit may be modular, e.g. enabling replacement of a reaction chamber pre-charged with a suitable fuei source, and / or replenishment of second reactant and / or catalyst modules.

One possible advantage of using thermai sensing of a remaining fuei oapaciiy of a fuel supply cartridge is that a pressure sensor and / or a flow sensor is not required within the pressure vessel of the reaction chamber or downstream flow path thereby avoiding the need for integration of electronic sensors into the reaction vessel and f or fuel delivery Sines. This maty reduce the complexify of the reaction chamber / cartridge design and mduoe: the number of sealing points or sealing surfaces required. Thermal sensing may be possible entirely outside the pressurised cavities of the fuel cartridge.

Where the temperature sensing functionality and the cartridge are separated from one another, the temperature sensing functionality may be incorporated into a fuel consuming device (such as a fuel ceil powered device).

With reference to figure 3, a fuel consuming device iQ may: include an interior chamber or other receptacle 31 for receiving a fuei supply cartridge 32, and a fuei ceil 33 for generating electrical power from fluid fuei supplied by the fuei supply cartridge 32 via fluid fuel conduit 34. The interior chamber 31 comprises one or more temperature sensors 38 disposed within the chamber configured to detect a thermal profile of the fuel supply cartridge 32 when it is installed in the receptacle 31. Like the temperature sensor i in figure 1, the temperature sensor 38 of figure 3 may comprise any suitable temperature sensor arrangement as previously described, such as a thermal sensor array or one or more thermal imaging devices. The temperature sensor 38 is configured to determine a remaining fuel capacity of the fuel supply 32 from the thermai profile. The thermal sensor 38 in the fuel consuming device 30 may generally have any of the features previously discussed In cohhestidn with the fuel cartridge 1 above.

Although the examples discussed above generally relate to iyai supplies that are particularly suited for the generation of hydrogen as a fluid fuel from a fuel source, the same principles can be used for the generation of other fluid fuels from alternative fuel sources, such as hydrocarbon fluid fuel from suitable fuel sources. yore generally, the principles of using a temperature sensor which is configured to detect a thermal profile of a reaction chamber and to thereby determine a remaining fuel capacity of a fuel supply within the reaction chamber can be generally extended to the principle of using a temperature sensor to detect a thermai profile of a reaction chamber and to-thereby determine an extent of progress of a reaction taking place within the reaction chamber from the measured thermai profile. The system may generally be pre-programmed with data relating to an initial: reactant amount and a thermai characteristic related to a rate of progress of the reaction or process to generate the expected product. Thereby, an expected future amount of product generation expected can be determined from the measured thermal profile.

The method may generally be applied for monitoring a reaction in which at least one reactant generates at least one product in an endothermic orexothermie process. The temperature sensor can detect a thermal profife: of the reactant and / or a confinement vessel containing the reactant· The thermal profile can be used to determine an extent of the reaction that has taken place in the reactant, and thereby determine from the extent of reaction, an amount of reactant remaining.

Other embodiments are intentlonaily within the scope of the accompanying claims.

Claims

CLAIMS i A fuel supply for a fuel cell, comprising a reaction chamber configured to generate fluid fuel from a fuel source: a temperature sensor configured to detect a thermal profile of the reaction chamber a remaining fuel capacity of the fuel supply from the thermal profile, I, The fuel supply of claim 1 in which the thermal profile detected by the temperature sensor comprises a spatial thermal profile of the reaction chamber.
3. The fuel supply of claim 2 in which the spatial thermal profile is Indicative of a location of a reaction within the reaction cn amber that varies as a function of fuel source remaining unspent. 4 The fuel supply of claim t in which the temperature sensor Is configured to defect·' a posllpri: of a temperature gradient; within the reaction chamber, and to determine remaining fuel capacity from the position of the Temperature gradient £L The fuel supply of claim 1 in which the thermal profile detected hy the temperature: Mnsdr comprises a temporal thermal profile of trie reaction chamber. is The fuel supply of claim 5 in which the tempera! thermal profile is indicative of an extent of readtibh that has occurred within: the reaction chamber over time and in which the sensor is configured to determine remaining fuel capacity based on the temporal thermal profile.
7. The fuel supply of ciaim 1 in which the temperafum sensor comprises a thermal imaging device,
8. The fuel supply of claim t in which the temperature sensor comprises an array of thermal sensors disposed adjacent to the reaction chamber.
9. The fuel supply of ciaim 1 in which the temperature sensor comprises a strip of temperature-sensitive material disposed adjacent to the reaction chamber.
10. The fuel sugpiy of claim 2 further Including: an orientation sensor configured to; determine ah orientation of the fuel supply; and a processor configured to determine remaining fuel capacity based on the spatial thermal prole and the orientation of the fuel supply.
11. The fuel supply of oMm 2 in which the spatial thermal profile of the reaction chamber detected by the: temperature Sensor indicates a fuel source / fuel gas boundary within the reaction chamber.
12. The fuel supply of ciaim 1 in which the reaction chamber is charged with a first reactant material and the fuel supply includes a reservoir of second reactant or cataiyst configured to be introduced into the reactant chamber to generate the fluid fuei.
13. The fuel supply of ciaim 1 comprising a removable fuei cartridge for use with a fuei ceil powered device.
14. A fuei consuming device comprising: a receptacle configured to receive a fuei supply cartridge; one or more temperature sensors disposed within the receptacle configured to detect a thermal profile of the fuel supply cartridge when it is installed in the receptacle, the temperature sensor being configured to determine a remainihifuei^ capacity of the fiaei supply from the thermal profile.

11,. The fuel consuming device of claim 14 fufthef cbm prising;: a fuel ceil; a fluid fuel conduit coupling the receptacle and; the fuel dell; the fuel celi configured to generate electrical power from fluid fuei supplied by a fuel supply cartridge when instated within the receptacle, via the field fuel conduit.
16.. A method1 of determining; a remaining fuel capacity of a fuel supply, comprising the steps of. initiating a reaction in a reaction chamber to generate fluid fuel from a fuei source; using a temperature sensor to detect a thermal profile of the reaction chamber containing the fuel source; and determining a remaining fuel capacity of the fuel supply from the thermal profile. IT. The method of claim 16 further including using the detected thermal profile to determine a spatial extent of the reaction,
18. The method of claim 16 further including using the detected thermal profile to determine a temporal: extent of the reaction,
19. The method of claim 17 further including using the detected thermal profile to detect the position of a fuel source f fuel gas boundary within the reaction chamber.
20. A fuel source substantially as described herein and with reference to the eecompenying: drawingsv
21. A reactor, comprising: a reaction chamber having: if least one reactant contained therein, which reactant: is configured to generate at. least one product in an endothermic or exothermic process; a temperature sensor configured to detect a thermal profile of the reaction chamber and to thereby determine an extent of the reaction that has taken place within the reaction chamber from the measured thermal prole,.
22. The reactor of claim 21 in which the reactor is a fuel supply, the reactant is a fuel source, and the product is a fluid fuel.
23. A method of momtoring a reaction in which at least one reactant generates at least one product in an endothermic or exothermic process:, the method comprising: using a temperature sensor to detect; a thermal profile of the reactant and / or a confinement vessel thereof; determining an extent of the reaction that has taken place in the reactant from the measured thermal profile; determining from said extent, an amount of reactant remaining,
24. The method of claim: 23 further comprising determining: an: amount: of product: still available for generation from said amount of reactant; remaining.
25. The method of claim 23 er claim 24 in which the reactant Is a fuel source and the product Is a fluid fuel.