ES3041808T3 - Heating systems and methods - Google Patents

Abstract

A heating system comprising: a liquid supply system; a cell configured to: receive liquid from the liquid supply system, heat it, and supply hot fluid; a work extraction system configured to extract useful work from the hot fluid exiting the cell; wherein the cell comprises: (i) a housing arranged to define an inner portion for receiving the liquid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to the fluid in the inner portion; and wherein the electrodes are configured to apply electrical energy to said fluid in the inner portion to generate one or more plasma bubbles to release energy into said fluid in the inner portion and into the housing to heat the fluid in the inner portion.

Description

DESCRIPTION

Heating systems and procedures

Technical field

[0001] The present invention relates to the field of systems and methods for generating heat. In particular, the present invention relates to systems and methods that use a cell to provide a heated fluid.

Background

[0002] Generally, power and/or heating generation may involve the combustion of some type of fuel. For example, fossil fuels may be used in a combustion process that heats water to generate steam and/or hot water. Steam may be generated to drive a turbine, which in turn may be used to generate electricity. Hot water may be generated for use in heating systems, where that hot water circulates throughout a building to provide heat. Electricity could also be used to generate hot water, such as in an electric boiler. It may be desirable to provide greater efficiency for such power and/or heating generation. US 2006/0201157 describes an arc hydrolysis steam generating procedure and apparatus. US 2020/0002828 describes related electrical power generating procedures and systems.

Summary

[0003] The aspects of the invention are set forth in the independent claims and the optional features are set forth in the dependent claims. The aspects of the invention may be provided together, and the features of one aspect may be applicable to other aspects.

[0004] In one aspect, a heating system is provided comprising: a liquid supply system; a cell configured to: receive liquid from the liquid supply system, heat it, and produce heated fluid; and a work extraction system configured to extract usable work from the heated fluid outlet of the cell. The cell comprises: (i) a housing arranged to define an inner portion for receiving liquid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to the fluid in the inner portion. The electrodes are configured to apply electrical energy to the fluid in the inner portion to generate one or more plasma bubbles to release energy into the fluid in the inner portion, and the housing to heat the fluid in the inner portion.

[0005] The embodiments may provide a high-exergy heated fluid from which work is extracted. Work may be extracted from this high-exergy heated fluid to provide heat and/or power generation. The embodiments may provide an efficient system for generating heat and/or power. The cell may comprise a plasma cell (e.g., a plasma-generating fuel cell).

[0006] The system may further comprise a controller configured to: (i) receive a signal indicating at least one operating parameter of the cell, and (ii) control the operation of the heating system based on that operating parameter. The controller may be configured to control the operation of the heating system so that the heat and/or plasma generation in the cell is above a threshold level. Controlling the operation of the heating system may comprise controlling at least one of: (i) the liquid supply to the cell by the liquid supply system, and (ii) the electrical power applied by the electrodes. The controller may be configured to control the operation to maintain at least one operating parameter for the cell within a selected range (e.g., to provide a selected level of cell performance).

[0007] The controller can be configured to control the fluid supply to the cell and/or the electrical power applied by the electrodes based on an indication of the heat demand that the cell must provide. If the indicated demand shows a higher heating requirement, the controller can be configured to increase at least one of the following: (i) the temperature of the fluid supplied to the cell, (ii) the pressure of the fluid supplied to the cell, (iii) the amount of fluid supplied to the cell, and (iv) the amount of electrical power applied by the electrodes. For example, controlling this operation can facilitate an increase in cell output (e.g., to provide more heated fluid and/or plasma generation within the cell).

[0008] The indicative signal of at least one operating parameter may include an indication of the quality and/or quantity of plasma generation within the cell. The controller may be configured to control the operation of the heating system so that the quality and/or quantity of plasma generation remains within a selected range. For example, the controller may be configured to provide at least a threshold amount of plasma generation. This selected threshold/range amount for plasma generation may be selected so that sufficient plasma generation occurs to provide selected heating characteristics for the heating system (e.g., so that the amount of heated fluid generated is within a selected range).

[0009] The indicative signal of the quality and/or quantity of plasma generation may comprise an indication of at least one of the following: (i) a pressure and/or temperature of the fluid exiting the cell, (ii) a quantity and/or type of electromagnetic energy present within the cell, (iii) vibration associated with the delivery of energy to one or more of the electrodes, (iv) a current and/or voltage flow associated with one or more of the electrodes, and (v) fluid flow dynamics within the cell. For example, higher pressures and/or temperatures (e.g., for fluid exiting the cell) may indicate greater plasma generation. Likewise, a higher rate of increase in pressure/temperature may indicate greater plasma generation. For example, an increase in either electromagnetic activity within the cell and/or vibration associated with the delivery of energy may provide an indication of greater plasma generation. For example, sudden changes in current or voltage may provide an indication of any change in plasma generation. Where the current begins to increase, this can indicate that an arc is about to form. For example, the controller can be configured to reduce or stop applying voltage to the first electrode if a change in current exceeds a threshold value (or if the rate of change of current exceeds a threshold), such as if the current becomes too high. Voltage can also be monitored to identify any voltage drops, such as those that occur in response to an arc, which may be providing less resistance to current flow. For instance, increased turbulence in the fluid flow within the cell can indicate increased plasma generation.

[0010] The controller may be configured to control at least one of: (i) the liquid supply to the cell based on the electrical energy applied by the plurality of electrodes, and (ii) the electrical energy applied by the plurality of electrodes based on the liquid supply to the cell. For example, by increasing the liquid supply and/or electrical energy, the controller may control the electrical energy/liquid supply (respectively) according to the change in the supply of the other. The change in the supply of one may be selected based on the change in the supply to the other (for example, the increase/decrease in one may be selected in proportion to the increase/decrease in the supply of the other). The indicative signal of at least one operating parameter may comprise an indication of a temperature associated with at least one of: the cell, the fluid in the cell, and the fluid leaving the cell. The controller can be configured to control at least one of the following: (i) the electrical power applied by the electrodes, (ii) the fluid supply to the cell, and (iii) an external heater, to increase the cell temperature, the fluid in the cell, and/or the fluid outlet from the cell if the temperature reading falls below a threshold level. The controller can also be configured to increase the electrical power applied by the electrodes to provide greater heating and/or decrease the fluid flow rate through the cell if the temperature reading falls below the threshold level.

[0011] An inner surface of the cell shell may comprise an electromagnetic energy-absorbing material arranged to convert incident photons into heat. At least a portion of the shell may be conductive. For example, the inner surface of the shell may be configured to generate heat in response to photons incident upon that surface. The shell (for example, its inner surface) may be configured to heat the fluid within the inner portion in response to heat generation from incident photons (for example, and/or other particles such as electrons). The shell may be configured to provide conductive heating of the fluid within the inner portion. The shell may be made of metal, for example, the shell may be made of steel. The shell may be formed from a plurality of different materials. One or more layers or sleeves may be provided to the shell. For example, the cell may include a sleeve located on the inner portion within the shell. The sleeve can be arranged to fit within the inner portion (e.g., it can sit adjacent to the inner portion of the housing). A plurality of such sleeves can be provided. Each sleeve can be arranged to provide different absorption/conductivity properties to other regions of the housing/cell. For example, the housing can be made of a first material (e.g., steel), and a sleeve made of a second material (e.g., aluminum) can be inserted within the housing. The housing and/or the sleeve can include a coating to further facilitate absorption and/or conduction. For example, a gold coating can be applied.

[0012] The liquid delivery system may be configured to supply liquid to the cell under pressure. The cell may be arranged to retain fluid within the casing under pressure. For example, the casing may comprise one or more compression devices configured to retain the inner portion of the casing under pressure, and/or the casing may be sufficiently rigid to resist expansion under pressure applied from within the inner portion. The liquid delivery system may be configured to heat the liquid before supplying it to the cell. The liquid delivery system may be configured to increase the temperature of the liquid before supplying it to the cell if the heat and/or plasma generation of the cell falls below a threshold level. The system may be arranged to provide a variable, continuous supply of liquid to the cell.

[0013] The plurality of electrodes may comprise: (i) an anode arranged to provide a conductive path for current to be applied to the fluid in the inner portion, and (ii) a cathode arranged to provide a conductive path away from the inner portion for current received from the anode through the fluid in the inner portion. The plurality of electrodes may further comprise a balance electrode arranged to provide an additional conductive path to or from the fluid in the inner portion. The anode and cathode (and, for example, the balance electrode) may be arranged concentrically with each other. The anode, cathode, and balance electrode may have the same coefficient of thermal expansion. The balance electrode may be arranged away from the conductive path between the anode and the cathode. For example, the conductive path from the anode to the cathode may be radially outward. The balance electrode may be offset from the anode/cathode in a different direction (e.g., along a longitudinal axis). The balance electrode may be closer to the anode than the cathode. For example, the balance electrode may run substantially perpendicular to the current path from the anode to the cathode (e.g., it may be parallel to the anode).

[0014] The cell may comprise a resistive element disposed between the anode and the cathode; for example, the resistive element may comprise quartz or a boron silicate glass material (for example, a high-strength material that can withstand high temperatures and/or pressures). The resistive element may have sufficient electrical resistance to act as an electrical insulator. The resistive element may be disposed within the conductive path between the anode and the cathode, for example, to provide increased electrical resistance between the anode and the cathode. For example, the resistive element may be located radially outward from the anode and radially inward from the cathode (for example, where the conductive path from the anode to the cathode extends radially outward).

[0015] The system may be configured to provide additional heating to one or more cell components (e.g., during a startup mode). The cell may comprise a heating element to provide such heating. For example, a heater may be located adjacent to the cell and/or a heating element may be integrated within a part of the cell. A heater may be included in a cell end cap (e.g., a cartridge heater may be provided within a cell end cap). In some examples, this heating may be provided by a resistive heating element. The resistive heating element may be part of the cell (e.g., voltage may be applied to a component such as an anode or resistive element to provide resistive heating, or to an additional resistive heating element or region of the cell). Such heating may be provided to raise the temperature associated with at least one of: the cell, the fluid within the cell, and the fluid outlet of the cell to the point where plasma is stimulated. For example, heating may be provided until bubbles appear (e.g., gas bubbles).

[0016] The liquid supply system may be configured to supply a fluid to the cell, such as water, that at least partially exhibits a non-Newtonian nature under the circumstances expected within the cell. For example, the liquid may be configured to resist the rapid expansion of the plasma within the cell. The system may further comprise a filter apparatus configured to filter the fluid outlet from the cell. The work extraction system may comprise at least one of: (i) a regulator for mass transfer of hot and/or pressurized fluid, (ii) a heat exchanger for heat transfer to a working fluid, and (iii) a power generation system, such as a steam-based power generation system. The heated fluid generated by the cell may be used on its own for downstream applications or, alternatively, may be used to heat one or more fluids for downstream applications. For example, the heated fluid generated by the cell may be used as a working fluid, or the heated fluid generated by the cell may be used to heat a separate fluid, which may then be used as a working fluid. The system may comprise a DC voltage source operable to apply a DC voltage to each of the electrodes.

[0017] In one aspect, a system is provided comprising: a cell configured to heat the liquid supplied thereto, the cell comprising: an inlet for receiving a liquid to be heated and an outlet for removing the heated fluid; a power management system configured to control the application of electrical power to the cell to control the heating of the fluid in the cell; a work extraction system coupled to the outlet and configured to extract usable work from the heated fluid outlet of the cell; and a fluid management system coupled to the inlet of the cell, and configured to: (i) supply liquid to be heated to the cell, and (ii) process heated fluid that has exited the cell and been used by the work extraction system.

[0018] The cell may comprise a cell as described herein. The work extraction system may comprise a work extraction system as described herein. The fluid management system may comprise a liquid supply system as described herein, for example, for supplying liquid to be heated to the cell.

[0019] The fluid management system may comprise: (i) a fluid supply coupling for connecting the system to a supply of fluid to be heated, and (ii) a drain coupling for disposing of the heated fluid that has been expelled from the cell and used by the work extraction system. The fluid management system may comprise a pump coupled to the fluid supply coupling and the cell inlet, where the pump can operate to supply fluid to the cell under pressure. The work extraction system may comprise a heat engine. The cell outlet may be coupled to a first engine inlet to allow the heated fluid outlet from the cell to drive the engine. The heat engine may be coupled to a generator configured to generate power in response to the engine's operation. The cell outlet may also be coupled to a first heat exchanger. A first engine outlet may be coupled to the first heat exchanger so that the heated fluid from the cell that has passed through the engine is directed to the first heat exchanger for heating. The first heat exchanger can be coupled to a second motor inlet to allow the superheated fluid from the heat exchanger to further drive the motor. The motor can be configured to operate at different ratios for the fluid entering through the first and second motor inlets. At least one of the motor and the first heat exchanger can be coupled to a second heat exchanger configured to extract more heat from the heated fluid exiting the cell.

[0020] The fluid management system may include a filter for filtering the heated fluid exiting the cell. The work extraction system may include at least one of: a heat management system configured to receive heated fluid exiting the cell and to use that heated fluid as a heat source or in a heat exchanger; and a power generation system configured to receive heated fluid exiting the cell and to use that heated fluid to generate power. The power generation system may be coupled to the power management system to supply generated power to it. The power management system may include an external coupling for connection to an external power source. The power management system may be configured to receive power from the external source and/or supply power generated by the power generation system to the external source.

[0021] In one aspect, a method is provided for providing a heated fluid for extracting usable work therefrom, the method comprising: supplying a liquid to be heated to a cell, wherein the cell comprises: (i) a shell arranged to define an inner portion for receiving the liquid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to the fluid in the inner portion; controlling the operation of the plurality of electrodes to apply electrical energy to the fluid in the inner portion to generate one or more plasma bubbles; generating heat in the shell adjacent to the inner portion in response to the shell receiving incident photons (e.g., and also electrons) associated with plasma bubbles in the inner portion; and using the shell to conductively heat the fluid in the inner portion.

[0022] In one aspect, a method is provided for controlling the operation of a heating system, the heating system comprising a cell comprising: (i) a housing arranged to define an inner portion for receiving fluid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to the fluid in the inner portion, the method comprising: controlling the operation of the electrodes to apply electrical energy to the fluid in the inner portion to generate one or more plasma bubbles to release energy from the plasma to the fluid in the inner portion and the housing to provide heating of the fluid in the inner portion, wherein controlling the operation of the electrodes comprises: receiving a signal indicative of at least one operating parameter associated with the cell and/or a fluid associated therewith; operating in a “cold start” mode when the operating parameter indicates that the heating and/or plasma generation is below a threshold level; and operating in a “normal” mode when the operating parameter indicates that the heating and/or plasma generation is above the threshold level; where operating in cold start mode comprises controlling at least one of: (i) the electrical power applied by the electrodes, (ii) the supply of liquid to the cell, and (iii) the operation of an external heater, to increase the temperature of the cell and/or the fluid associated with it in the event that the operating parameter indicates that the heating and/or plasma generation is below a threshold level.

[0023] Aspects of the present invention may also provide one or more computer program products comprising computer program instructions configured to control a processor to perform any of the procedures described in this invention.

Figures

[0024] The following are some examples of the present invention, by way of example only, with reference to the figures, where:

Fig. 1 shows a schematic diagram of an exemplary heating system.

Fig. 2 shows a schematic diagram of an exemplary heating system.

Fig. 3 shows a schematic diagram of an exemplary cell.

Fig. 4 shows a block diagram of an exemplary heat and power generation system.

Fig. 5 shows a schematic diagram of an exemplary heat and power generation system.

[0025] Similar reference numbers are used in the drawings to indicate similar items.

Specific description

[0026] The embodiments of the present invention are directed to systems for generating heat and/or energy. Such systems can provide the heating of a liquid to produce a heated fluid. The heated fluid can then be used for heating and/or power generation purposes. To generate the heated fluid, liquid can be supplied to a cell. Electrical energy can be applied to the liquid contained in the cell through one or more cell electrodes. The application of this electrical energy to the fluid within the cell causes the gas bubbles within the cell to form plasma bubbles. Each plasma bubble will be a localized region that has a higher pressure/temperature than the surrounding fluid. The surrounding fluid can limit the expansion of the plasma bubbles so that, while electrical energy is still being applied, these bubbles will emit electromagnetic energy. For example, photons can be emitted by atoms (or molecules) within the plasma bubbles. In turn, these emitted photons can heat the substance upon which they impinge. For example, this can provide heating of the cell casing and/or the fluid within the cell. In turn, this allows the cell to produce a heated fluid for use in a heating and/or power generation system. The heated fluid may contain liquid and/or gas, and in some cases, it may also contain plasma materials.

[0027] An exemplary heating system will now be described with reference to Fig. 1.

[0028] Fig. 1 shows a schematic diagram of a heating system 50. The heating system 50 includes a liquid supply system 10, a cell 100, and a work extraction system 20. The cell 100 includes a fluid inlet 12 and a fluid outlet 22. The cell 100 has a housing 120 that defines an internal portion 125 of the cell 100. The cell 100 also includes a plurality of electrodes, which, as shown, includes a first electrode 111 and a second electrode 112. The cell 100 may comprise a plasma cell (e.g., a plasma-generating fuel cell).

[0029] The housing 120 of cell 100 encapsulates the internal portion 125. The fluid inlet 12 provides a flow path for fluid into the internal portion 125 of cell 100. The fluid outlet 22 provides a flow path for fluid exiting the internal portion 125 of cell 100. Alternatively, the internal portion 125 of cell 100 may be sealed by the housing 120. The fluid supply system 10 is coupled to the fluid inlet 12 of cell 100. The work extraction system 20 is coupled to the fluid outlet 22 of cell 100. The couplings between the fluid supply system 10 and the fluid inlet 12, and between the work extraction system 20 and the fluid outlet 22, are shown as an annular flow path. However, it will be appreciated that this is purely for illustrative purposes, and any suitable flow path may be provided. Furthermore, although not shown in the Figs., the working extraction system 20 can also be coupled to the liquid supply system 10 (e.g., to facilitate heating and/or pressurization of the liquid to be supplied to the internal portion 125).

[0030] The first electrode 111 is disposed at least partially within the inner portion 125 of cell 100. The second electrode 112 may also be disposed at least partially within the inner portion 125 of cell 100. The first and second electrodes 112 are arranged concentrically. The first electrode 111 extends within a central region of the inner portion 125 of the cell 100. The second electrode 112 is arranged radially outward from the first electrode 111. The second electrode 112 may be cylindrical, as is the first electrode 111. The first and second electrodes 112 are arranged coaxially in the example shown in Fig. 1. The second electrode 112 is located adjacent to an inner surface of the housing 120 (however, in some examples, the second electrode 112 may be integrated with the housing 120, e.g., to form part of it, and/or a portion of the housing 120 may provide the second electrode 112, e.g., if such a portion of the housing is electrically conductive).

[0031] A first end of the first electrode 111 is located outside the inner portion 125 of the housing 120. A second end of the first electrode 111, distal to the first end, is located inside the inner portion 125 of the housing 120. The second electrode 112 may extend along part or all of the length of the inner portion 125 of the housing 120. At least one end of the second electrode 112 may extend outside the inner portion 125 of the cell 100. Although not shown in Fig. 1, each of the first and/or second electrode 112 may be coupled to a power source. For example, each electrode may have one end extending outside the inner portion 125 (e.g., inside the housing 120), and this end may be coupled to the power source. In some examples, the housing 120 can provide a ground connection and the first electrode 111 can be connected to a positive terminal of the power source.

[0032] The housing 120 may be cylindrical. The fluid inlet 12 is arranged at one end of the housing 120 opposite the fluid outlet 22. The first and second electrodes 112 extend along an axis extending from the fluid inlet 12 to the fluid outlet 22 (e.g., a longitudinal axis of cell 100). The fluid outlet 22 may be arranged vertically higher (e.g., above, directly above) the fluid inlet 12.

[0033] The liquid supply system 10 is arranged to supply liquid to cell 100. Liquid can be supplied to cell 100 through fluid inlet 12. The liquid supply system 10 may comprise a coupling to a liquid supply, such as a liquid reservoir. The liquid supply system 10 is configured to control the supply of this liquid to cell 100. For example, the liquid to be supplied may partially or entirely comprise a fluid that exhibits non-Newtonian behavior in the environment of cell 100. The liquid may be water or an aqueous solution.

[0034] The work extraction system 20 is arranged to receive heated fluid from cell 100. The heated fluid can exit cell 100 through fluid outlet 22. The heated fluid can comprise liquid and/or gas. For example, this can be a combination of gas and liquid, e.g., steam with a few drops of water. Fluid outlet 22 is arranged to allow the flow of this heated fluid from cell 100 to be used by the work extraction system 20. For example, steam created within cell 100 can rise and exit through fluid outlet 22. The work extraction system 20 is configured to utilize the heated fluid outlet from cell 100. The work extraction system 20 can be configured to receive this heated fluid and use it as part of a heated fluid supply (e.g., for heating purposes). The work extraction system 20 can be configured to receive this heated fluid and to use it to generate power. For example, this heated fluid can be used to drive a generator, for example, by using a steam engine.

[0035] Shell 120 is configured to encapsulate inner portion 125. Shell 120 is arranged to define inner portion 125 to provide a region where the liquid can be heated. An inner surface of shell 120 (e.g., facing/defining inner portion 125) can be configured to generate heat in response to incident photons (e.g., shell 120 can be conductive). The inner surface can comprise the region of shell 120 that is adjacent to inner portion 125. This can comprise part of shell 120 and/or an additional component, such as a layer/film provided therein, to generate heat in response to incident photons. For example, the inner surface can be configured to absorb electromagnetic energy, such as in the form of visible light. The inner surface is configured to heat up as it receives incident photons. The inner surface is configured to heat the fluid within the inner portion 125, for example, as it is heated by incident photons. The shell 120 may be made of a metal, such as steel. The shell 120 is configured to retain fluid in the inner portion 125 under pressure.

[0036] Fluid inlet 12, internal portion 125, and fluid outlet 22 are arranged to define a flow path for fluid to flow through internal portion 125 of housing 120. Internal portion 125 is arranged to receive fluid to be heated through fluid inlet 12. Cell 100 is arranged to heat this fluid in internal portion 125 to provide heated fluid. Fluid outlet 22 is arranged to provide a flow path for this heated fluid away from internal portion 125.

[0037] The first and second electrodes 111, 112 are configured to provide a current flow path through the inner portion 125 of cell 100. One of the electrodes 111, 112 can provide an anode and the other can provide a cathode. For example, the first electrode 111 can provide the anode to carry the current into the inner portion 125 of cell 100. The second electrode 112 can provide the cathode to carry the current out of the inner portion 125 of cell 100. The first and second electrodes 112 are separated from each other. The first electrode 111 is arranged to receive a voltage so that a potential difference exists between the first and second electrodes 111, 112. The first and second electrodes 111, 112 are capacitively arranged. The presence of fluid in the inner portion 125 can provide a conductive path between the first and second electrodes 112. The fluid will provide electrical resistance between the two electrodes 111 and 112. The first and second electrodes 112, with fluid in cell 100, can effectively provide a circuit with capacitance and resistance. The first and second electrodes 111 and 112 are configured to provide voltage to the fluid and/or plasma within the inner portion 125.

[0038] In operation, the liquid supply system 10 supplies a liquid through fluid inlet 12 and into the internal portion 125 of cell 100. In this example, the liquid will be water, but other liquids can be used. The liquid supply system 10 functions to supply water to cell 100 so that cell 100 is filled with water. Any gas that was previously in cell 100 can be expelled through fluid outlet 22 of cell 100. Cell 100 can then be substantially filled with water.

[0039] A voltage is applied to the first electrode 111 (anode). This will cause some current to flow into the water.

Due to the electrical resistance of water, this current flow and resistance will cause some heating of the water (e.g., I²R heating). This resistive heating process continues as a voltage is applied to the first electrode 111. As the temperature of the water inside the inner portion 125 increases, microbubbles of gas will begin to form within the water in the inner portion 125. These may be vapor bubbles forming or air bubbles being released that were trapped in the water supplied to the inner portion 125 of cell 100. As a result, some pockets of gas will develop within the liquid in the inner portion 125 of cell 100. With the continued application of voltage to the first electrode 111, plasma bubbles will be generated within the inner portion 125 of the shell 120. These bubbles will release energy into the surrounding fluid and the inner surface of the shell 120. This, in turn, provides heating of the fluid within the inner portion 125.

[0040] Without wishing to limit ourselves to theory, applying voltage to the first electrode 111 will charge the capacitor provided by the first and second electrodes 112. As the fluid within the inner portion 125 heats up, its permittivity can change, and this can change the capacitance of cell 100 (e.g., between the first and second electrodes 111, 112). For example, when water is used, its permittivity will decrease as it heats up (and then also when it turns into steam). In particular, when microbubbles of gas (e.g., steam) begin to form within the liquid in the inner portion 125, these will provide localized regions of lower permittivity. This process can effectively provide a collapse of permittivity in localized regions. For example, when water is used, the permittivity difference between the bubbles forming in the water and the surrounding water can be a factor of approximately 40 (e.g., the capacitance per unit volume in those bubbles can be 1/40 that of the surrounding water). During this process, the volumetric energy density of the fluid and/or plasma within the inner portion 125 will remain constant. Due to the permittivity collapse within the gas bubbles, the capacitance will decrease in this region. Since the volumetric energy density remains constant and the capacitance decreases, the voltage per meter will increase accordingly (e.g., to conserve energy according to E = 1/2 CV²). For examples where water is used, the voltage per meter will increase by a factor of approximately V⁴⁰.

[0041] Without adhering strictly to theory, with electrical energy still being applied to the first electrode 111, these gas microbubbles (being less dense than the surrounding liquid) will attempt to expand rapidly into their environment. However, the surrounding liquid will resist this expansion, for example, due to the non-Newtonian nature of the liquid under these conditions. This will cause the microbubbles to rapidly increase in temperature and pressure. In turn, their capacitance will decrease even further (for example, causing an increase in dV/dr), resulting in a higher voltage across the bubble. With sufficient voltage across the bubble, ionization can occur, leading to the formation of plasma within the bubble. Thus, one or more plasma bubbles can form in the liquid in the inner portion 125. The plasma can have an even lower density than the gas, and therefore, with a voltage still being applied to the first electrode 111, the plasma bubble will attempt to expand rapidly. In particular, this plasma bubble generation process will occur rapidly, so each plasma bubble will drive a rapid expansion. In turn, this will cause non-Newtonian fluid responses in the liquid of the inner portion 125 of cell 100. For example, when water is used, the water does not immediately yield to the pressure wave caused by the plasma bubble trying to expand. Therefore, the plasma bubble remains at a relatively fixed volume (e.g., it can only expand relatively slowly). While the plasma volume remains relatively constant, the temperature and pressure inside this bubble increase rapidly in response to the voltage drop caused by the voltage applied to the first electrode 111.

[0042] Without adhering strictly to theory, to accommodate this high energy level within the plasma bubble, the atoms (and molecules) inside the bubble can absorb energy. Therefore, the energy levels (e.g., states) of these particles can increase. Within the plasma, the electrons of the atoms can move to higher electron energy levels and/or the spin states of these particles can change. For example, the spin states of the hydrogen atom can change from its lower-energy para state to its higher-energy ortho state. Molecules can also move to higher rotational and/or vibrational energy levels, and/or further splitting of these molecules can occur. As a result, the atoms within each bubble will have disproportionately high energy levels (e.g., compared to conventional fluids/the fluid within the inner portion 125).

[0043] Without adhering strictly to the theory, photon emission from the plasma can occur to accommodate the high energy within the plasma. Electrons can transition to lower energy states, and/or changes to lower energy vibrational/rotational/spin states can occur for atoms/molecules. It is this return to lower energy configurations that results in photon emission (e.g., to accommodate the drop in energy levels according to the Bohr model). This photon emission can occur on a relatively large scale. When water is used, a large proportion of this photon emission occurs in the visible light spectrum.

[0044] The photons emitted by each plasma bubble will be absorbed by the fluid in the inner portion 125 or the shell 120 of cell 100. In response to receiving these incident photons, the fluid and/or the shell 120 will heat up as it absorbs them. The inner surface of the shell 120, in particular, can absorb a large number of these photons and thus increase its temperature. As the inner surface of the shell 120 heats up, it will, in turn, provide conductive heating to the fluid within the inner portion 125. This can lead to the formation of convection currents and thus increase the turbulence of the fluid within the inner portion 125 of cell 100. As a result of this process, the fluid within the inner portion 125 will heat up. Most of the liquid supplied to the internal portion 125 of cell 100 can evaporate to provide a gas (e.g., steam). It should be appreciated in the context of the present invention that some of the fluid exiting cell 100 may have somewhat unconventional configurations, or at least lower energy, compared to the liquid supplied to cell 100. This is a consequence of the plasma generation and subsequent energy release that occurred within cell 100.

[0045] This heated fluid then passes through fluid outlet 22. Typically, the heated fluid is in the form of vapor, which is generated within the internal portion and rises and exits through fluid outlet 22. The heated fluid is then used in the work extraction system 20 to extract usable work from the heated fluid. For example, this heated fluid can be used for power generation and/or heat distribution.

[0046] Other examples of the present invention will now be described with reference to Fig. 2.

[0047] Fig. 2 shows a schematic diagram of a heating system 50. As with Fig. 1, the heating system 50 in Fig. 2 includes a liquid supply system 10, a cell 100, and a work extraction system 20. These components of the heating system 50 in Fig. 2 are similar to those in Fig. 1; for example, the features of the heating system 50 in Fig. 1 could be used in combination with the features of the heating system 50 in Fig. 2.

[0048] The liquid supply system 10 may further include a liquid reservoir 14, a heater 16, and a pump 18. The cell 100 includes a fluid inlet 12, a fluid outlet 14, and a housing 120 defining an internal portion 125. The cell 100 includes a first electrode 111 and a second electrode 112. In addition, as shown in Fig. 2, the cell 100 may include a third electrode 113 and a resistive element 115. The cell 100 may comprise a plasma cell (e.g., a plasma-generating fuel cell).

[0049] The heating system 50 may also include a power source 30 and a controller 40. A plurality of sensors are shown by means of black circles to illustrate the possible sensing capabilities of the system 50. The sensors shown include a power source sensor 41, a fluid inlet sensor 42, a first electrode sensor 43, a second electrode sensor 44 and a third electrode sensor 45, a fluid outlet sensor 46 and an internal portion sensor 47.

[0050] The liquid supply system 10 can connect the liquid reservoir 14 to the fluid inlet 12 of cell 100. The liquid reservoir 14 can be connected to the fluid inlet 12 via the pump 18 and/or the heater 16 (both shown in Fig. 2). The liquid supply system 10 is configured to supply liquid to the internal portion 125 of cell 100. The liquid supply system can supply liquid from a liquid source, such as the liquid reservoir 14 shown in Fig. 2, or it can comprise a connection to a liquid supply, for example, a mains water supply.

[0051] The first and second electrodes 112 can be arranged within cell 100 as described above with reference to Fig. 1. In addition, the third electrode 113 is also provided in the inner portion 125 of cell 100. The third electrode 113 is optional and may or may not be included. When included, a first end of the third electrode 113 may be located outside the inner portion 125, and the third electrode 113 may extend from the first end to a second end located within the inner portion 125. The second end of the third electrode 113 may be located close to the second end of the first electrode 111 within the inner portion 125. The first and third electrodes 111, 113 may be parallel (e.g., coaxial). The second and third electrodes 112, 113 may be parallel (e.g., coaxial). The first electrode 111 can extend from the outside of the first end of the housing 120 into the inner portion 125 toward an opposite end of the housing 120. The third electrode 113 can extend from the outside of the opposite end of the housing 120 into the inner portion 125 toward the first end. The first and third electrodes 111 and 113 can extend into the inner portion 125 such that there is no spatial overlap between these electrodes 111 and 113 (e.g., their respective second ends do not touch/overlap). The second electrode 112 can extend along the inner portion 125 from or outside the first end or to or outside the opposite end. The distance between the second end of the first electrode 111 and the second end of the third electrode 113 may be less than the smallest distance between the first electrode 111 and the second electrode 112. The third electrode 113 may be located far from an expected current path between the first and second electrode 112.

[0052] A resistive element 115 may also be included in the inner portion 125. The resistive element 115 may also be cylindrical. The resistive element 115 may be arranged to increase the electrical resistance of the conductive path between the first electrode 111 (anode) and the second electrode 112 (cathode). The resistive element 115 may extend around most of the inner portion 125 (e.g., along the length and width of the inner portion to prevent most possible conductive paths from the anode to the cathode). The resistive element 115 may be located between the first/third and second electrodes 111, 112. For example, the resistive element 115 may be located radially outward from the first/third electrode 111, 113, but not as far radially outward as the second electrode 112. The resistive element 115 may extend along part or all of the length of the inner portion 125. The resistive element 115 may be arranged in a current flow path between the first electrode 111 and the second electrode 112, for example, such that the current would have to flow through the resistive element 115 to pass from the first electrode 111 to the second electrode 112. The resistive element 115 may extend along one or both ends of the inner portion 125 (for example, to reduce the probability of a conductive path from anode to cathode other than through the element). resistive 115).

[0053] The power source 30 may comprise a DC source (for example, there may be an AC-to-DC converter to provide DC). The power source 30 may be coupled to one or more components of the heating system 50. Fig. 2 illustrates several of these possible couplings with solid lines. For example, these may comprise some form of conductor to provide a conductive connection from the power source 30 to such a component. The power source 30 may be coupled to the first electrode 111 and/or to either the second electrode 112 or the third electrode 113. The cell 100 may also include a heater, such as a resistive heater (for example, a cartridge heater). The power source may also be coupled to the heater. The power source 30 could be coupled to the resistive element 115 (for example, to provide resistive heating), as shown in Fig. 2. However, it should be appreciated that the resistive element need not be coupled to the power source. Instead, it can be included just to increase the resistance between the first and second electrodes 111, 112.

[0054] Controller 40 can be coupled to each of the sensors. Controller 40 can also be coupled to one or more of the power source 30, heater 16, and pump 18. Fig. 2 illustrates these couplings with dashed lines. These couplings can be wired or wireless.

[0055] The liquid supply system 10 is configured to supply liquid to the internal portion 125 of cell 100. The controller 40 can be configured to control the operation of the liquid supply system 10. For example, the liquid supply system 10 can selectively heat (using heater 16) and/or pressurize (using pump 18) liquid from the liquid reservoir 14 to be supplied to the internal portion 125 of cell 100. The controller 40 can be configured to control the operation of heater 16 and/or pump 18 to control the temperature and/or pressure of the liquid supplied to cell 100.

[0056] The power source 30 can be configured to apply a voltage to the first electrode 111 (e.g., to provide the operation described above with reference to Fig. 1). The power source 30 can also be configured to apply a voltage to the third electrode 113 (and/or, for example, a cell heater 100). The power source 30 can also be coupled to the second electrode 112 to receive a current drawn from it. The power source 30 can be configured to selectively apply a voltage, for example, using high-voltage DC. The controller 40 can be configured to control the operation of the power source 30. For example, the controller 40 can be configured to control at least one of: the magnitude of the voltage applied by the power source 30, the timing of the voltage supply, and/or the components to which the voltage is applied.

[0057] The third electrode 113 can be active or passive. When active, a voltage is applied to the third electrode 113. When passive, the third electrode 113 can be conductive to receive current within the inner portion 125, but without receiving power from the power supply 30. The third electrode 113 can be configured to provide a balancing electrode (e.g., it can be arranged to balance the electric field/current generated within the inner portion 125). The controller 40 can be configured to control the operation of the power supply 30 to selectively control whether (and/or how much) voltage is applied to the third electrode 113.

[0058] The resistive element 115 may be configured to have a relatively high resistance (e.g., compared to the resistance of the electrodes and/or the fluid within the inner portion 125). The resistive element 115 may have sufficient resistance to effectively provide an electrical insulator (between the anode and cathode).

[0059] In some examples, the cell includes a heater configured to provide heat in response to the application of a voltage to it, e.g., to provide resistive heating (I2R). The heater could be a region of the housing or a separate component configured to provide resistive heating (e.g., integrated into a part of the housing, such as an end cap). The heater could be arranged to heat the fluid in the internal portion 125 and/or the housing 120 in response to the application of a voltage to it. The controller 40 can be configured to control the operation of the power source 30 to selectively control whether (and/or how much) voltage is applied to the heater. In some examples, the resistive element 115 could provide the heater.

[0060] Controller 40 can be configured to receive a signal indicating at least one operating parameter of cell 100. Controller 40 can be configured to control the operation of heating system 50 based on this received signal. For example, controller 40 can be configured to control the operation of at least one of the heater 16, pump 18, and/or power source 30 according to the received signal. Controller 40 can also be configured to control the heat and/or pressure of the liquid supplied to internal portion 125.

[0061] Controller 40 can be configured to control whether and/or how much voltage is applied to one or more of the first electrode 111, the third electrode 113, and/or the heater. In other words, controller 40 can be configured to control the liquid supply to the internal portion 125 of cell 100 and/or the electrical power to be applied by the electrodes of cell 100.

[0062] Controller 40 can be configured to control operation based on at least one received signal indicative of one or more operating parameters of cell 100. The signal can be received from one or more of the sensors. It should be noted that the exact nature of the received signal and/or the sensor from which it is received should not be considered limiting. Exemplary sensors are shown in Fig. 2, which can provide information indicative of one or more operating parameters of system 50.

[0063] The power source sensor 41 can be configured to provide an indication of the operation of the power source 30. The power source sensor 41 can be configured to provide an indication of the magnitude of the energy (e.g., voltage) being applied and/or can provide any relevant feedback on the signal being applied by the power source 30. For example, the power source sensor 41 can be configured to provide an indication of any vibration associated with the voltage being applied by the power source 30 (e.g., to the first sensor). The fluid inlet sensor 42 can be configured to provide an indication of at least one property of the fluid to be supplied to the internal portion 125. For example, this may include an indication of the pressure and/or temperature of the fluid to be supplied. As another example, the fluid inlet sensor 42 can be configured to provide an indication of one or more chemical properties of the fluid being supplied to the internal portion 125 (e.g., indicative of the chemical composition of that fluid, such as percentage of impurities/additives, etc.). The fluid outlet sensor 46 can be similar to the fluid inlet sensor 42. For example, the fluid outlet sensor 46 can be configured to provide an indication of the temperature, pressure, and/or chemical composition of the fluid exiting cell 100. The fluid outlet sensor 46 can also be configured to provide an indication of any relevant power setting changes for the fluid exiting cell 100 (e.g., if any additional composition is present).

[0064] The first electrode sensor 43, the first electrode sensor 44, and the third electrode sensor 45 can be configured to provide an indication of one or more properties of the relevant electrical energy present at them. The sensors can provide an indication of a voltage and/or current present at the relevant electrode. For example, an electrode sensor can be configured to provide an indication of how the current and/or voltage at that electrode varies with time (e.g., to provide an indication of a time derivative of the current/voltage).

[0065] The internal portion sensor 47 is configured to provide an indication of the conditions within the internal portion 125 of cell 100. The internal portion sensor 47 may be located within the internal portion 125 of housing 120; for example, it may be attached to an internal wall of housing 120 (as shown in Fig. 2). Alternatively, the internal portion sensor 47 may be located outside the external portion but configured to provide some indication of the conditions within internal portion 125. The internal portion sensor 47 may be configured to provide an indication of the fluid flow dynamics within internal portion 125—for example, to provide an indication of whether there is any turbulent flow and/or how turbulent the flow is. This could include the use of a flow meter, a microphone, or any other suitable sensor. The sensor in internal portion 47 can be configured to provide an indication of the electromagnetic energy present within internal portion 125 (for example, an indication of the amount and/or type of electromagnetic emission produced). For example, the sensor in internal portion 47 can comprise an antenna suitable for detecting the presence of such electromagnetic energy/emissions and/or can comprise some type of camera (for example, as part of an optical fiber) configured to obtain an indication of light present in cell 100. The sensor in internal portion 47 can also be configured to provide an indication of the activity status occurring within cell 100.

[0066] In operation, the heating system 50 of Fig. 2 functions very similarly to the heating system 50 described above with reference to Fig. 1. That is, the power source 30 applies electrical energy (e.g., a voltage) to the first electrode 111 to heat the fluid in the inner portion 125. This heating occurs through resistive heating and also through heating by incident light emitted by plasma bubbles within the inner portion 125. In addition, capacitance can be provided between the first and third electrodes 113, and/or between the second and third electrodes 113. This can provide a balancing effect to the electric field within the inner portion 125 of the cell 100. The third electrode 113 can provide a balancing effect if it is provided as a floating electrode (e.g., in a passive state) and if a voltage is applied to the third electrode 113 (e.g., in an active state).

[0067] Additionally, the controller 40 can be configured to control the operation of the heating system 50 according to any of several different control loops. Each control loop can provide a feedback loop where indicative data of an operating parameter of cell 100 is obtained (for example, from a sensor), and the controller 40 controls the operation of a component of the heating system 50 based on this data. The data can be obtained from any suitable sensor (for example, any of the sensors shown in Fig. 2 and described above). The controller 40 can control the operation of any suitable component of the heating system 50, such as controlling the liquid supply to the internal portion 125 of cell 100 (for example, controlling the heater 16 or the pump 18) and/or controlling the electrical power applied by one or more of the electrodes (for example, controlling the power supplied by the power source 30).

[0068] Four exemplary control loops will now be discussed. In the first example, the operation of cell 100 will be described in a 'normal' mode, where at least one property is monitored and/or regulated to provide greater efficiency for the operation of cell 100. In the second and third examples, the operation of cell 100 will be described to increase and decrease the output of cell 100, respectively. In a fourth example, the operation of cell 100 will be described when it is in a 'start' mode.

[0069] In the first example, the operation of heating system 50 is controlled in a normal, continuous-operation mode. Here, controller 40 is configured to receive a signal indicating an operating parameter from cell 100, and controller 40 is configured to control the operation of system 50 so that the operating parameter remains within a desired range for the performance of cell 100. Cell 100 is designed to provide heated fluid as its output. Therefore, the operating parameter can provide an indication of the output of cell 100. For example, the operating parameter can provide an indication of how efficiently cell 100 is performing and/or an indication of the magnitude of the heat generation provided by cell 100 (for example, it can provide an indication of the quantity/temperature of the heated fluid generated by cell 100 per unit of time). It will be appreciated in the context of the present invention that it is not necessary to determine the cell performance per se, but instead, the controller 40 can control the operation of cell 100 based on an indicator of the cell performance.

[0070] Controller 40 can be configured to receive an indication of cell performance. The cell performance indication can provide an indication of the operating status of cell 100. This can include an indication of the quantity/temperature of the heated fluid generated by cell 100 and/or an indication of the quality of plasma generation occurring within cell 100. The indicator can be based on a temperature and/or pressure of the heated fluid generated by cell 100 (e.g., it can be an indication of such temperature and/or pressure). For example, such an indication can be obtained using the fluid outlet sensor 46. The indication can be based on either the temperature/pressure of the fluid supplied to cell 100 (e.g., as detected by the fluid inlet sensor 42) or the temperature/pressure of the heated fluid exiting cell 100 (e.g., as detected by the fluid outlet sensor 46). The indication can be based on the amount of heating provided by cell 100 (e.g., a difference between inlet and outlet temperatures) and/or on the heating rate provided by cell 100.

[0071] As an example, controller 40 can be configured to receive a signal indicating the temperature of the heated fluid exiting cell 100. If the heated fluid is outside a selected range (e.g., above an upper threshold temperature and/or below a lower threshold temperature), controller 40 can control the operation of heating system 50 to increase or decrease the temperature, as appropriate, so that the outlet temperature returns to the selected range. This may further include controller 40 determining whether the fluid supplied to cell 100 is heated above a threshold amount and/or within a threshold time period. Controller 40 can then control the operation of heating system 50 to produce a sufficient amount of heating and/or sufficiently rapid heating.

[0072] In addition to, or as an alternative to, receiving a direct indication of the temperature/pressure of the heated fluid exiting cell 100, controller 40 can receive a signal indicative of the cell's performance. For example, controller 40 can receive a signal indicating the quantity and/or quality of plasma generation occurring within cell 100. Controller 40 can then control the operation of heating system 50 so that the quantity and/or quality of plasma generation remains within a selected range. This, in turn, can control the generation of heated fluid by cell 100, since plasma generation within cell 100 ultimately leads to the heating of the fluid within cell 100.

[0073] Controller 40 can be configured to obtain an indication of a plasma generation property within cell 100 based on a signal received from a sensor. The indication of the plasma generation property can be determined based on temperature and/or pressure data for the fluid entering and/or exiting cell 100. The amount of plasma generation can be determined based on the amount of heat generated and/or the rate at which the fluid is heated. For example, faster/greater heating may indicate greater plasma generation. Controller 40 can be configured to determine that plasma generation is within a selected range if the amount and/or rate of heating by cell 100 is within a selected range.

[0074] The amount of plasma generation can be determined based on an indication obtained from the conditions within the inner portion 125 of the housing 120 (e.g., using the sensor in inner portion 47). An indication that the fluid within inner portion 125 is moving turbulently may indicate increased plasma generation (e.g., because the inner portion of the housing 120 provides more conduction heating, resulting in convection currents). Alternatively, or additionally, an indication that more electromagnetic energy is present (e.g., more light is visible/more electromagnetic waves are detected) may indicate increased plasma generation. The controller 40 can be configured to determine that plasma generation is within a selected range if the amount of turbulence and/or electromagnetic energy/emissions is within a selected range.

[0075] The amount of plasma generated can be determined based on an indication of current and/or voltage at one of the electrodes. For example, controller 40 can obtain an indication of a voltage applied to the first electrode 111, and an indication of a resulting current passing through the first electrode 111 (e.g., using the sensor at the first electrode 43). Controller 40 can be configured to monitor voltage and current data over time and to determine, based on this voltage and current data, when satisfactory plasma is generated. For example, controller 40 can control power source 30 to increase the voltage applied to the first electrode 111 over time, and the controller can monitor the resulting current. As the voltage increases, the current will also initially increase before becoming relatively stable as the voltage continues to rise. Once a threshold voltage is reached, the current will begin to increase, and the rate of increase of the current will increase with the increase in voltage. Controller 40 can be configured to detect that successful plasma generation has occurred in the region where the current begins to increase again. For example, controller 40 can be configured to determine that successful plasma generation has occurred once the current begins to increase again. Controller 40 can then control power source 30 so that it no longer increases the voltage applied to the first electrode 111.

[0076] The amount of plasma generation can be determined based on a vibration indication provided to the power source 30 in response to the application of a voltage to the first electrode 111. For example, this can provide an indication of the plasma generation occurring in the fuel, since vibrations are produced due to plasma generation. The controller 40 can be configured to determine that plasma generation is within a selected range if the detected vibration falls within that range.

[0077] The preceding examples describe operating parameters of cell 100 that controller 40 can configure to determine and/or receive indicative signals. Based on obtaining an indication of any of these operating parameters, controller 40 can be configured to control the operation of heating system 50. If the obtained indication is outside a selected range (for example, above an upper threshold value and/or below a lower threshold value), controller 40 can control the operation of system 50 so that a value for that parameter falls within the selected range. To do this, controller 40 can control the fluid supplied to cell 100 and/or the electrical energy applied to the fluid within cell 100.

[0078] Controller 40 can be configured to control the liquid supplied to cell 100 such that at least one operating parameter is within a selected range. The control of the liquid supply can comprise at least one of the following: (i) controlling the temperature of the liquid supplied to the internal portion 125 of cell 100, (ii) controlling the pressure of the liquid supplied to the internal portion 125 of cell 100, and/or (iii) controlling the quantity of liquid supplied to the internal portion 125 of cell 100 within a selected time window. Controller 40 can be configured to control the operation of heater 16 and/or pump 18 to control the temperature and/or pressure of the liquid supplied to cell 100. The fluid inlet 12 can comprise one opening for receiving liquid, or it can comprise a plurality, for example, to provide a plurality of inlet points for liquid to flow into the cell. Controller 40 can be configured to control the operation of pump 18 to regulate the fluid flow rate through cell 100, for example, to control how much fluid is delivered to cell 100 per unit of time. The liquid supply system 10 can be configured to provide a continuous flow of liquid to cell 100, and controller 40 can control the rate at which liquid is supplied to cell 100.

[0079] In the event that the operating parameter indicates that a greater output from the cell is required (for example, that cell 100 needs to heat the fluid more), the controller 40 can control the liquid supply system 10 to provide at least one of: (i) liquid to cell 100 at a higher temperature, (ii) liquid to cell 100 at a higher pressure, and/or (iii) more liquid to cell 100. For example, if the operating parameter indicates that plasma generation is below a threshold, the controller can increase the heat and/or pressure supplied to cell 100.

[0080] Controller 40 can be configured to control the electrical energy applied to the electrodes of cell 100 such that at least one operating parameter is within the selected range. This may include at least one of the following: (i) controlling the amount of time during which a voltage is applied to the first electrode 111, (ii) controlling the voltage applied to the first electrode 111, (iii) controlling the voltage applied to the second electrode 112, and/or (iv) controlling the voltage applied to the heater. When the operating parameter indicates that temperature generation needs to be increased and/or plasma generation is below a threshold, controller 40 can control power source 30 to increase the applied energy. For example, if plasma and/or heat generation is below a threshold value, controller 40 can apply a voltage (or apply a higher voltage) to the heater and/or the first electrode 111.

[0081] Controller 40 can be configured to control both the electrical power applied by the electrodes of cell 100 and the liquid supply to cell 100 (for example, both can be controlled simultaneously). Controller 40 can control one depending on how it is controlling the other. For example, controller 40 can select how to control the electrical power applied by the electrodes of cell 100 based on how it controls the liquid supply to cell 100 (and/or vice versa). If controller 40 determines that increased plasma generation is required, controller 40 can increase the voltage applied to the heater and/or the first electrode 111, as well as increase the temperature and/or pressure of the water supplied to cell 100. If controller 40 determines that increased heated fluid production is required, controller 40 can increase the voltages applied to the electrodes and/or the heater, as well as increase the amount of fluid supplied to cell 100.

[0082] In the second and third examples, controller 40 is configured to receive a demand signal indicative of a demand on the output of cell 100. The demand signal may indicate that more or less output from cell 100 is required. For example, this demand may be independent of the efficiency of cell 100; cell 100 may be operating within a threshold range for a relevant operating parameter, but the demand signal may indicate that the output should change (e.g., increase or decrease).

[0083] If the demand signal indicates that less output is required, controller 40 is configured to control the fluid supplied to cell 100 and the electrical power applied to the electrodes of cell 100. As demand decreases, controller 40 will decrease the fluid supply to cell 100. For example, controller 40 can decrease the fluid flow rate through cell 100. The fluid can still be supplied to cell 100 at the same or similar temperature and/or pressure. Controller 40 can also reduce the electrical power applied. For example, controller 40 can decrease the voltage applied to the first electrode 111. Controller 40 can still supply the same or similar voltage to the third electrode 113 and/or heater. Controller 40 can still control the operation, for example, as described above, so that plasma generation remains within a selected range even though overall output is reduced.

[0084] If the demand signal indicates that more output is required, controller 40 can control operation in the opposite manner. Controller 40 can increase the liquid supply rate to cell 100 and the amount of electrical power applied to the electrodes of cell 100. Controller 40 can be configured to control the operation of cell 100 to prevent the liquid flow rate through cell 100 from exceeding a threshold amount of plasma generation, where the flow rate is too high for sufficient plasma generation to occur. Controller 40 can still control operation, for example, as described above, so that plasma generation remains within a selected range even if the total output is increased.

[0085] In the fourth example, controller 40 is configured to control the operation of system 50 in a startup mode. For example, when cell 100 is first powered on, it may take some time before it can operate at higher efficiencies. In particular, the housing 120 of cell 100 may be cooler than it would be during use. Controller 40 can be configured to determine that startup operating conditions are to be used. For example, controller 40 can obtain an indication of the temperature of relevant components of system 50 (e.g., housing 120) to determine whether system 50 should operate in a startup mode, and/or controller 40 can determine, based on an indication of previous use (e.g., that system 50 has not been used recently), that startup mode is to be used.

[0086] In startup mode, controller 40 is configured to control the operation of cell 100 to provide additional heating. Controller 40 can increase the voltage applied to the first electrode 111 to provide additional resistive heating. Alternatively, controller 40 can apply a voltage to the heater, for example, to provide resistive heating. For example, controller 40 can control operation so that a higher voltage is applied to the heater in startup mode than during normal operation (e.g., no voltage can be applied to the heater during normal operation). For example, controller 40 can be configured to control the heater's operation to provide more heating during startup (e.g., more heating power can be used). Controller 40 can also control the operation of an additional heater, such as a cartridge heater, to heat cell 100/internal portion 125. Controller 40 can control the fluid supply to cell 100 so that the fluid supplied to cell 100 is at a higher temperature and/or pressure and/or the fluid flow rate through cell 100 is lower when in startup mode. Controller 40 can control the electrical power applied to the electrodes and/or the heater so that it is higher when in startup mode.

[0087] Controller 40 can be configured to monitor at least one operating parameter of cell 100 to determine when to exit startup mode. For example, while an indication obtained from a temperature associated with cell 100 remains below a threshold temperature value, controller 40 can control the operation of system 50 to enter startup mode. Once this temperature exceeds the threshold temperature value, controller 40 can control the operation of system 50 to function under normal operating conditions. For example, less liquid preheating may occur when in normal mode. Controller 40 can be configured to determine that sufficient plasma generation is occurring (for example, in the manner described above) and, in response, switch to normal operating mode.

[0088] Another example of cell 100 will now be described with reference to Fig. 3. Cell 100 in Fig. 3 corresponds closely to the one described above, so the description of the relevant components will not be repeated.

[0089] Fig. 3 shows a cell 100. The cell 100 includes a first electrode 111, a second electrode 112, a third electrode 113, and a resistive element 115. The cell 100 also includes a housing 120 that defines an internal portion 125 and has a fluid inlet 12 and a fluid outlet 22. The cell 100 also includes a first end cap 122, a second end cap 124, and a compression device 126. The cell 100 may comprise a plasma cell (e.g., a plasma-generating fuel cell).

[0090] The internal portion 125 extends from a first end of the housing 120, which includes the fluid inlet 12, to a second end of the housing 120, which includes the fluid outlet 22. The internal portion 125 may be cylindrical. The housing 120 encapsulates the internal portion 125 and defines the fluid inlet 12 and the fluid outlet 22. In this example, the resistive element 115 is adjacent to the inner wall of the housing 120, although in other examples, the resistive element 115 may be integral with the inner wall or separate from the wall and within the internal portion 125. The first end cap 122 and the second end cap 124 may also be part of the resistive element 115; for example, they also provide increased resistance to a conductive path from the anode to the cathode. The second electrode 112 is arranged within (e.g., integral with) the inner wall of the housing 120. The first and third electrodes 113s are arranged at least partially within the inner portion 125. The first electrode 111 extends from the outside of the first end into the inner portion 125. The third electrode 113 extends from the outside of the second end into the inner portion 125. There is a gap between the two in the inner portion 125. The three electrodes and the resistive element 115 can be coaxial (e.g., they can be concentric).

[0091] The first end cap 122 encloses the inner portion 125 at the first end. The second end cap 124 encloses the inner portion 125 at the second end. End caps 122 and 124 are part of the housing 120 for the inner portion 125. The first end cap 122 is non-conductive. The second end cap 124 is non-conductive. Each end cap may effectively form part of a resistive barrier for a conductive path from the anode to the cathode (for example, the end caps may form part of the resistive element 115 or work in combination with it). Each end cap 122 and 124 includes one or more openings to allow fluid flow through it. One or both end caps may have an opening near their center. For example, the opening(s) in the first end cap 122 may be located close to the first electrode 111. The opening(s) may be arranged to facilitate the flow of liquid into the inner portion 125 while inhibiting the probability of a conductive path forming from the anode to the cathode through said opening(s). The first end cap 122 may have a plurality of openings to facilitate multiple different points through which the liquid may flow into the inner portion 125. The compression device 126 is located within the first end of the housing 120 adjacent to the first end cap 122. The compression device 126 may comprise any suitable thrust means, such as a spring. Each end of the housing 120 may have a thicker material, as shown in Fig. 3. At least a portion of the housing 120 may be electrically grounded. As shown in Fig. 3, the first end of the housing 120 is grounded. One or both end caps may include a heating element (e.g., a resistive heater), which can be used to heat the liquid within the inner portion 125 (e.g., during startup). For example, the power supply 30 can be coupled to a heater in the end cap (e.g., in the first end cap 122). The controller 40 can be configured to control the application of power to the heater in the end cap to provide heating.

[0092] The first electrode 111 may include a conductor extending the length of the electrode. The conductor may be provided within an insulating body to form the electrode. An insulating covering may be provided for at least part of the electrode region within the inner portion 125 (e.g., the insulating covering may be provided at the end of the first electrode 111 that is disposed in the inner portion 125). For example, the electrode may have a conductor extending along a central axis, where that conductor is radially surrounded by an insulator along the length of the conductor that is in the inner portion 125 (e.g., it may be along the entire length). The first electrode 111 may also include a support at its end furthest from the inner portion 125. The support may comprise suitable fastening means, such as a flange, for joining to the first end cap 122. The support may also include a sealing and joining means for joining the first electrode 111 to the first end cap 122 and sealing the inner portion 125. For example, a radially extending flange may provide a sealing face. For example, a screw thread may allow the end cap 122 to be secured to the electrode to seal the inner portion 125. A similar arrangement may be provided for the third electrode 113 and, for example, its arrangement with the second end cap 124.

[0093] The compression device 126 is configured to apply pressure on the first end cap 122 toward the inner portion 125 of the housing 120. The compression device 126 can facilitate retaining the inner portion 125 of the housing 120 under pressure. The housing 120 is arranged to allow fluid flow into the inner portion 125 through the fluid inlet 12 and vapor/liquid flow out through the fluid outlet 22. The housing 120 is arranged to provide structural support to allow the inner portion 125 to be held under pressure with fluid inside. For example, the side wall(s) of the housing 120 are arranged to support the radial expansion of the inner portion 125, and the end walls of the housing 120 are arranged to resist the longitudinal expansion of the inner portion 125. The operation of cell 100 is similar to that described above with reference to Figs. 1 and 2, and will therefore not be described again here.

[0094] The heating systems described in this invention can be used in larger generating systems. Examples of such larger generating systems will now be described with reference to Figs. 4 and 5.

[0095] Fig. 4 shows a heat and power generation system 1000. The heat and power generation system 1000 comprises a power management system 200, a cell 100, a heat management system 300, a fluid management system 400, and a power generation system 500. Also shown in Fig. 4 is a network coupling 220. The cell 100 may comprise a plasma cell (e.g., a plasma-generating fuel cell).

[0096] Figure 4 shows a block diagram to illustrate the functional interrelationship between the different component systems of the heat and power generation system 1000. However, it should be appreciated that this is intended to demonstrate the functional connections, rather than the specific structural connections. It will be appreciated that the structural arrangement of the different component systems may be interconnected (for example, as will be described later with reference to Figure 5).

[0097] As shown in Fig. 4, the power management system 200 is coupled to cell 100. Cell 100 is coupled to the heat management system 300. The heat management system 300 is coupled to each of the power generation systems 500 and the fluid management system.

400. The fluid management system 400 is coupled to cell 100. The power generation system 500 is coupled to the power management system 200. This coupling is intended to demonstrate the functional interrelationships between the different component systems. The power management system 200 can also be coupled to the network coupling 220 (for example, as shown in Fig. 4).

[0098] The power management system 200 is configured to control the application of power to cell 100. The power management system 200 can control the electrical power (e.g., voltage) applied to the first electrode 111 of cell 100. The power management system 200 can also control the electrical power (e.g., voltage) applied to the remaining electrodes and/or the heater of cell 100. The power management system 200 can also control the operation of any pump 18 and/or heater 16 to supply fluid to cell 100 under pressure and/or at a higher temperature. Therefore, the power management system 200 can control the operation of cell 100 to generate heated fluid.

[0099] Cell 100 is configured to operate as described above (e.g., to apply electrical power within its internal portion 125 to generate heated fluid).

[0100] Heat management system 300 is configured to receive the heated fluid generated by cell 100. Heat management system 300 is configured to utilize this heated fluid to provide relevant thermal work. For example, heat management system 300 may be configured to provide heating using this heated fluid, e.g., for heating buildings, etc. Heat management system 300 may comprise one or more components to provide heat transfer from the heated fluid from cell 100 to another component and/or substance. For example, heat management system 300 may comprise one or more heat exchangers.

[0101] The power generation system 500 is configured to receive the heated fluid generated by cell 100. The power generation system 500 is configured to use this heated fluid to generate power (e.g., electrical power). Fig. 4 shows the output from cell 100 being supplied to the heat management system 300, and from the heat management system 300 to the power generation system 500. However, it will be appreciated in the context of the present invention that one of these systems may be omitted, or the two systems may be provided by the same components. The power generation system 500 may comprise one or more generators for generating electricity based on the movement of the heated fluid (e.g., using pressurized gas to drive a turbine to generate electricity). This arrangement may also include some heat management (e.g., for distributing heat to other parts of the power generation system 500). In some examples, the heated fluid can be used for both heating and power generation. The heat management system 300 can then control the distribution of the heated fluid accordingly (for example, to control the distribution of the heated fluid to the power generation system 500). For example, the work extraction system 20 described above may comprise such a heat management system 300 and/or power generation system 500.

[0102] The energy generated by the power generation system 500 can then be supplied to the power management system 200. For example, this energy generated by the power generation system 500 can in turn be used by the power management system 200 to power cell 100 to provide further power generation. The power management system 200 can also be coupled to the grid coupling 220 to receive and/or transmit energy to the grid. For example, during startup mode, the power management system 200 can obtain all of its energy from the electrical grid, but after startup, at least some of its energy can be received from the power generation system 500. After startup, some of the energy generated by the power generation system 500 can be supplied to the grid coupling 220 for distribution elsewhere.

[0103] Fluid management system 400 is configured to supply fluid to cell 100 (for example, as described above for fluid supply system 10). Fluid management system 400 is configured to receive fluid that has exited cell 100. Fluid management system 400 can be configured to process fluid that was heated by cell 100 and has since been used by heat management and/or power generation systems. The heated fluid generated by cell 100 may be at high temperature and/or pressure. The heat management and/or power generation systems are configured to extract usable work from this high-temperature/high-pressure fluid. Once usable work has been extracted, the fluid may be at much lower temperatures and pressures. For example, it may exit cell 100 as a gas at high temperature and pressure, and once it has been completely used for extraction work, it may be converted back into a liquid (e.g., at a lower temperature). The fluid management system 400 is configured to process this spent fluid. Processing the spent fluid may involve returning it to the environment and/or processing (e.g., filtering) the fluid so that it can be reused as a liquid to be supplied to cell 100.

[0104] In operation, the power management system 200 receives power (e.g., from the grid coupling 220 and/or the power generation system 500). The power management system 200 applies electrical power to cell 100 (e.g., to the first electrode 111). The fluid management system 400 supplies fluid to cell 100. The electrical power applied to cell 100 in turn heats the fluid supplied to cell 100 so that cell 100 produces a heated fluid. This heated fluid is received by the heat management system 300 and/or the power management system 200, which extract usable work (e.g., for heating and/or power generation) from the heated fluid. Once this work has been extracted, any energy generated by the power generation system 500 is supplied to the power management system 200. The spent fluid is supplied to the fluid management system, which processes this spent fluid. This process can be repeated, for example, continuously, to provide heat and/or power generation.

[0105] A more specific example of a heat and power generation system 1000 will now be described with reference to Fig. 5.

[0106] Fig. 5 shows a heat and power generation system 1000. The heat and power generation system 1000 comprises a cell 100. Also included are a power source 30, a pump 18, and a drain 15. The system 1000 includes a plurality of heat exchangers, which, as shown in Fig. 5, includes a first heat exchanger 301, a second heat exchanger 302, a third heat exchanger 303, and a fourth heat exchanger 304. The system 1000 further includes a heat engine 510 having a first drive region 511 and a second drive region 512, and a generator 520. The cell 100 may comprise a plasma cell (e.g., a plasma-generating fuel cell).

[0107] Cell 100 is wired to receive two inputs (liquid and electricity) and to provide one output (heated fluid). The inputs to cell 100 are shown at the bottom right of cell 100, and the output is at the top.

[0108] The outlet of cell 100 is coupled to the first heat exchanger 301 and the heat engine 510. A flow path for the outlet can be divided into two, with one path coupled to the first heat exchanger 301 and another path coupled to the heat engine 510. In particular, the outlet of cell 100 is coupled to the first drive region 511 of the heat engine 510. The heat engine 510 has a first motor inlet to receive fluid for driving the motor 510 in the first drive region 511. The first drive region 511 is also coupled to a first motor outlet to remove the fluid that has driven the motor 510 in the first drive region 511. The first motor outlet is also coupled to the first heat exchanger 301.

[0109] Motor 510 also includes a second motor inlet and a second motor outlet. The second motor inlet is for receiving fluid to drive motor 510 in the second drive region 512. The second motor outlet is for removing the fluid that has driven motor 510 in the second drive region 512. The second motor inlet is also coupled to the first heat exchanger 301. For example, fluid can flow from the outlet of the first motor to the inlet of the second motor through the first heat exchanger 301. Motor 510 is coupled to a generator. Each of the first and second drive regions 511 and 512 of motor 510 can be coupled to the generator. The first and second drive regions 511 and 512 can drive motor 510 in different ratios. Both can contribute to driving the generator and thus to generating electricity.

[0110] The first heat exchanger 301 can be coupled to the second heat exchanger 302. System 1000 can be configured so that the heated fluid from cell 100 flows through the first heat exchanger 301 and into the second heat exchanger 302. The second heat exchanger 302 can also be coupled to the third and/or fourth heat exchanger 303, 304.

[0111] Power source 30 is coupled to cell 100. Power source 30 provides an input to the fuel supply (e.g., to supply electrical power to the electrodes of cell 100). Power source 30 may include a coupling to receive power from the grid (e.g., power source 30 may receive three-phase power). Power source 30 may include a converter (e.g., AC to DC) to provide a DC output, such as a high-voltage DC output. The high-voltage DC output can then be supplied to cell 100, for example, to be applied to the first electrode 111. Power source 30 may also be coupled to the generator to receive electricity generated by it. Power source 30 can receive either AC or DC from the generator. When receiving AC, it can be converted to DC (e.g., using the same AC-to-DC converter or a different one). Some of the electricity generated by the generator can be supplied to the electrical grid, for example, for use elsewhere.

[0112] The third heat exchanger 303 and/or pump 18 can be connected to the inlet of cell 100. The liquid to be supplied to cell 100 can be heated and/or pressurized using the third heat exchanger 303 and/or pump 18. This can provide the liquid inlet to cell 100, which is used to generate heated fluid. The heated fluid outlet from cell 100 is finally connected to a drain 15. For example, the fluid that has passed through both regions 511, 512 of the motor 510 can be supplied to the drain 15. Likewise, the fluid that has passed through any of the heat exchangers (for example, the second, third, and/or fourth heat exchangers 302, 303, 304) can be connected to the drain 15.

[0113] System 1000 is arranged to provide multiple uses for the heated fluid generated by cell 100, e.g., to extract work from the heated fluid in multiple ways. System 1000 is configured to provide a high-temperature, high-pressure fluid outlet from cell 100 to drive the first drive region 511 of motor 510. The generator is configured to generate electricity from this drive of the first drive region 511. The first heat exchanger 301 is configured to reheat this fluid that has driven the first drive region 511 of motor 510. The first heat exchanger 301 is arranged to exchange heat between the heated fluid from cell 100 and the fluid that drove the first drive region 511 of motor 510. System 1000 is configured to use the reheated fluid that drove the first drive region 511 of motor 510 to drive the second drive region 512 of motor 510. The second drive region 512 of motor 510 is configured to have a simpler ratio (e.g., so that less is required). energy to drive a rotation) compared to the first drive region 511. The fluid passing through the second drive region 512 may have a lower pressure than the first drive region 511. The generator is configured to generate electricity in response to the drive of the first and/or second drive regions 511, 512 of the motor 510.

[0114] System 1000 is arranged for the heated fluid that has passed through the first heat exchanger 301 and/or exited the second motor outlet to provide additional heating use, where relevant. For example, System 1000 may be arranged to deliver the heated fluid to one or more of the second, third, and/or fourth heat exchangers 302, 303, and 304 to extract usable heating work from this heated fluid. Any of these heat exchangers 302, 303, and 304 may be coupled to an external component to utilize such heat. System 1000 may be configured to exchange heat from the heated fluid with the fluid to be supplied to cell 100 to preheat it before sending it to cell 100. System 1000 is arranged to dispose of any remaining fluid using drain 15.

[0115] In operation, fluid is supplied to cell 100, and electrical energy is applied to the electrodes of cell 100 to generate a heated fluid. The heated fluid exits cell 100 and flows into the first heat exchanger 301 and the first drive region 511 of motor 510. The heated fluid flows through the first drive region 511 to drive motor 510 and the generator to produce electricity. This fluid then flows to the first heat exchanger 301, where it is reheated by the heated fluid that traveled directly (i.e., not through motor 510) to the first heat exchanger 301 from cell 100. The fluid that has traveled through motor 510 is then reheated before flowing through the second drive region of the motor. This fluid then drives motor 510 and the generator to produce electricity. The fluid that has passed through the second drive region 512 of the motor 510 and/or through the first heat exchanger 301 away from the motor 510 is then used in other heat exchangers 302, 303, and 304 to extract more usable thermal work from the fluid. This fluid is then disposed of through drain 15.

[0116] It will be appreciated in the context of the present invention that the examples described herein are not intended to be limiting. Alternative and/or additional features may also be included. For example, reference has been made to concentric electrodes, for example, which are arranged coaxially with a first central electrode 111 and a second electrode 112 located radially outward from the first electrode 111. However, this arrangement may be reversed. Alternatively, the electrodes need not be arranged concentrically. For example, the two electrodes could be arranged in an alternative manner, such as as plate electrodes, for example, two parallel plates, or as parallel wires or other parallel objects such as spheres.

[0117] Reference has been made here to the electrodes of cell 100. The first electrode 111 may provide an anode, the second electrode 112 a cathode, and/or the third electrode 113 a balance electrode. It should be appreciated in the context of the present description that each electrode may provide a conductive path; for example, each electrode may comprise a conductor extending along the length of the electrode. The anode may comprise a conductor providing a conductive path from outside to the inner portion 125 within the inner portion 125 to the distal end of the conductor within the inner portion 125. The cathode may comprise a conductor providing a conductive path from inside, or adjacent to, the inner portion 125 to away from the inner portion 125. The balance electrode may comprise a conductor providing a conductive path toward the inner portion 125 from outside to the inner portion 125 or away from the inner portion 125 from inside the inner portion 125. The first electrode 111 may be arranged to pass closer to the third electrode 113 than to the second electrode 112; for example, the minimum distance between a point on the first electrode 111 and a point on the third electrode 113 may be less than that between the first and second electrodes 112. For example, the minimum distance between the first and third electrodes may be much less than that between the first and second electrodes 111. 112.

[0118] The examples described in this invention relate to the use of a single cell. However, it should be appreciated in the context of this description that multiple cells can be provided. For example, the operation of the different cells can be programmed to provide a constant output of heated fluid over time. The operating timing of each cell can be compensated so that the total output of heated fluid over time remains relatively constant. For example, it should be appreciated that each cell can have a heated fluid output that varies with time, and the multiple cells can have their operations timed so that the output of all the cells combined is more consistent than the output of any single cell. The controller 40 can be configured to control the supply of liquid to each cell and/or the application of electrical power to the electrodes to provide a constant output of heated fluid. For example, one or more sensors can be used for each cell to determine its operating parameters, such as its heated fluid output.

[0119] It should be noted that the liquid supply to cell 100 can occur continuously over time or only at discrete intervals. The controller 40 can be configured to control whether or not the liquid is delivered to cell 100. For example, cell 100 may include a fluid inlet valve operable to control whether or not the fluid can flow into the internal portion 125, and/or the operation of pump 18 can be controlled to supply liquid to cell 100 or not. There may be continuous fluid renewal within cell 100; for example, fluid is continuously supplied to cell 100 and heated fluid is continuously discharged from cell 100 (for example, as a gas through fluid outlet 22). There may be discrete time periods for fluid input such that a unit of liquid is supplied to cell 100 (e.g., enough to fill cell 100), then no more liquid is supplied while electrical power is applied to the electrodes to provide heated fluid, e.g., once all the fluid has been heated sufficiently to be released through fluid outlet 22. Another unit of liquid may then be supplied to cell 100. It should be appreciated that, for this mode of operation, several different cells working together may comprise timing operation such that while the unit is being delivered to one cell, another cell applies electrical power to the fluid in its cell. It will be appreciated that multiple different cells (e.g., more than two) may be used with timings all offset from each other, e.g., so that when one is almost finished heating, another is halfway through heating, and another is just beginning to heat, and so on.

[0120] The inner surface of the housing 120 has been described as an electromagnetic energy-absorbing surface. This may be a property of the material used to provide the housing 120, for example, steel, and/or a coating may be provided on the inner surface to facilitate the absorption of electromagnetic energy (for example, from photon emissions). It should be appreciated that absorbing electromagnetic energy may comprise receiving incident photons (for example, in the visible light spectrum) and, in response to such photons striking the surface, generating heat. It will also be appreciated that electrons or other particles (for example, charged particles emitted by the plasma/plasma cooling process) may also strike the inner surface of the housing 120. The inner surface of the housing 120 may also be configured to generate heat in response to such incident particles. For example, resistive heating may be provided in response to the flow of electrons through the inner surface.

[0121] It will be appreciated from the preceding discussion that the examples shown in the figures are merely illustrative and include features that can be generalized, eliminated, or replaced as described in this invention and as set forth in the claims. With reference to the drawings in general, it will be appreciated that schematic functional block diagrams are used to indicate the functionality of the systems and apparatus described in this invention. In addition, processing functionality can also be provided by devices that are compatible with an electronic device. However, it will be appreciated that it is not necessary to divide the functionality in this way, and it should not be considered to imply any particular hardware structure other than that described and claimed below. The function of one or more of the elements shown in the drawings can be subdivided and/or distributed throughout the apparatus described. In some examples, the function of one or more elements shown in the drawings can be integrated into a single functional unit.

[0122] Certain features of the procedures described in this invention can be implemented in hardware, and one or more functions of the apparatus can be implemented in procedural steps. It will also be appreciated in the context of the present invention that it is not necessary to perform the procedures described in this invention in the order in which they are described, nor necessarily in the order in which they are depicted in the drawings. The procedures described in this invention can be implemented in computer programs, or in hardware, or in any combination thereof. Computer programs include software, middleware, firmware, and any combination thereof. Such programs can be provided as network signals or messages and can be recorded on computer-readable media, such as tangible computer-readable media capable of storing computer programs in a non-transient form. Hardware includes computers, portable devices, programmable processors, general-purpose processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and logic gate arrays. For example, any controller 40 described in this invention may be provided by any control apparatus, such as a general-purpose processor configured with a software product configured to program the processor to operate according to any of the procedures described in this invention. The functionality of the controller 40 may be provided by an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a logic array configuration, or any other control apparatus.

Claims (16)

1. A heating system (50) comprising: a liquid supply system (10); a cell (100) configured to: receive liquid from the liquid supply system (10), heat it and produce heated fluid; a work extraction system (20) configured to extract usable work from the heated fluid outlet of the cell (100); and a controller (40); wherein the cell (100) comprises: (i) a housing (120) arranged to define an internal portion (125) for receiving liquid to be heated, and (ii) a plurality of electrodes including a first electrode (111) configured to apply electrical energy to the fluid in the internal portion (125); where the first electrode (111) is configured to apply electrical energy to said fluid in the inner portion (125) to generate one or more plasma bubbles to release energy in said fluid in the inner portion (125) and the housing (120) to heat the fluid in the inner portion; the system is characterized in that the controller (40) is configured to reduce or stop the application of voltage to the first electrode (111) in the event that a change in current or a rate of change in current exceeds a threshold value. 2. The heating system (50) comprising: a liquid supply system (10); a cell (100) configured to: receive liquid from the liquid supply system (10), heat it and produce heated fluid; and a work extraction system (20) configured to extract usable work from the heated fluid outlet of the cell (100); wherein the cell (100) comprises: (i) a housing (120) arranged to define an inner portion (125) for receiving liquid to be heated, and (ii) a plurality of electrodes including a first electrode (111) configured to apply electrical energy to the fluid in the inner portion (125) and a second electrode (112); the system is characterized in that the second electrode (112) is capacitively arranged with the first electrode (111); and where the system (50) is configured to apply electrical energy to the first electrode (111) to charge the capacitor provided by the first and second electrodes (111; 112) to generate one or more plasma bubbles in the fluid in the inner portion (125) to release energy in said fluid in the inner portion (125) and the shell (120) to heat the fluid in the inner portion (125). 3. The heating system (50) according to claim 2, wherein the system (50) further comprises a controller (40) or the heating system (50) according to claim 1, wherein the controller (40) is configured to: (i) receive a signal indicating at least one operating parameter of the cell (100), and (ii) control the operation of the heating system (50) based on said operating parameter. 4. The heating system (50) according to claim 3, wherein the controller (40) is configured to control the operation of the heating system (50) so that the generation of heat and/or plasma in the cell (100) is above a threshold level. 5. The heating system (50) according to any of claims 3 to 4, wherein the control of the operation of the heating system (50) comprises the control of at least one of: (i) the supply of liquid to the cell (100) by the liquid supply system (10), and (ii) the electrical energy applied by the electrodes. 6. The heating system (50) according to claim 5, wherein the controller (40) is configured to control the liquid supply to the cell (100) and/or the electrical power applied by the electrodes based on a demand indication obtained for heating to be provided by the cell (100), optionally wherein in the event that the demand indication obtained indicates a higher heating demand to be provided by the cell (100), the controller (40) is configured to increase at least one of: (i) the temperature of the liquid supplied to the cell (100), (ii) the pressure of the liquid supplied to the cell (100), (iii) the amount of liquid supplied to the cell (100), and (iv) the amount of electrical power applied by the electrodes. 7. The heating system (50) according to any of claims 3 to 6, wherein the signal indicating at least one operating parameter comprises an indication of the quality and/or quantity of plasma generation within the cell (100); and wherein the controller (40) is configured to control the operation of the heating system (50) so that the quality and/or quantity of plasma generation remains within a selected range, optionally wherein the signal indicative of a quality and/or quantity of plasma generation comprises an indication of at least one of: (i) a pressure and/or temperature of the fluid leaving the cell (100), (ii) a quantity and/or type of electromagnetic energy present within the cell (100), (iii) vibration associated with the supply of energy to one or more of the electrodes, (iv) a current flow and/or voltage associated with one or more of the electrodes and (v) fluid flow dynamics within the cell (100). 8. The heating system (50) according to any of claims 3 to 7, wherein the controller (40) is configured to control at least one of: (i) the liquid supply to the cell (100) according to the electrical energy to be applied by the plurality of electrodes, and (ii) the electrical energy to be applied by the plurality of electrodes based on the liquid supply to the cell (100). 9. The heating system (50) according to any of claims 3 to 8, wherein the signal indicating at least one operating parameter comprises an indication of a temperature associated with at least one of: the cell (100), the fluid in the cell (100), and the fluid outlet of the cell (100); and where the controller (40) is configured to control at least one of: (i) the electrical power applied by the electrodes, (ii) the liquid supply to the cell (100), and (iii) an external heater (16), to increase the temperature of the cell (100), the fluid in the cell (100), and/or the fluid outlet from the cell (100) in the event that the temperature indication is below a threshold level, optionally where the controller (40) is configured to increase the electrical power applied by the electrodes to provide greater heating and/or decrease the liquid flow rate through the cell (100) in the event that the temperature indication is below the threshold level. 10. The heating system (50) according to any of the preceding claims, wherein at least one of: an internal surface of the cell housing (120) (100) comprises an electromagnetic energy absorption material arranged to convert incident photons into heat; The liquid supply system (10) is configured to supply liquid to the cell (100) under pressure, and the cell (100) is arranged to retain fluid in the housing (120) under pressure; The system (50) further comprises a heater (16) coupled to, or part of, the cell (100), and wherein the system (50) is configured to increase the electrical power applied to the heater (16) to increase the temperature associated with at least one of: the cell (100), the fluid within the cell (100), and the fluid outlet of the cell (100): The work extraction system (20) comprises at least one of: (i) a regulator for mass transfer of hot and/or pressurized fluid, (ii) a heat exchanger for heat transfer to a working fluid, and (iii) a power generation system (200) such as a steam-based power generation system; and The liquid supply system is configured to increase the heating of the liquid before supplying it to the cell in case the heat and/or plasma generation of the cell is below a threshold level. 11. The heating system (50) according to any preceding claim, wherein the plurality of electrodes comprises: (i) an anode (111) arranged to provide a conductive path for current to be applied to the fluid in the inner portion (125), and (ii) a cathode (112) arranged to provide a conductive path away from the inner portion (125) for current received from the anode (111) through the fluid in the inner portion (125), optionally wherein the system (50) further comprises a balancing electrode (113) arranged to provide an additional conductive path to or away from the fluid in the inner portion (125), for example wherein the anode (111), cathode (112), and balancing electrode (113) all have the same coefficient of thermal expansion, optionally wherein the balancing electrode (113) is separated from the conductive path from the first electrode (111) to the second electrode (112), for example, wherein the The balance electrode extends perpendicularly away from the conducting path from the first electrode (111) to the second electrode (112), for example, where the balance electrode (113) is arranged to be closer to the first electrode (111) than the second electrode (112). 12. The heating system (50) according to claim 11, wherein at least one of: The cell (100) comprises a resistive element (115) disposed between the anode (111) and the cathode (112), for example, where the resistive element (115) comprises quartz; and The anode (111) and the cathode (112) are arranged concentrically with each other. 13. A method for providing a heated fluid to extract usable work therefrom, the method comprising: supplying a liquid to be heated to a cell, wherein the cell comprises: (i) a housing arranged to define an internal portion for receiving the liquid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to the fluid in the internal portion; controlling the operation of the plurality of electrodes to apply electrical energy to the fluid in the internal portion to generate one or more plasma bubbles, wherein the control of the application of electrical energy to a first electrode (111) comprises reducing or stopping the application of a voltage to that electrode (111) in the event that a change in current or a rate of change in current exceeds a threshold value; generate heat in the casing near the inner portion in response to the casing receiving incident photons associated with plasma bubbles in the inner portion; use the casing to conductively heat the fluid in the internal portion. 14. A method for providing a heated fluid for extracting usable work therefrom, the method comprising: supplying a liquid to be heated to a cell, wherein the cell comprises: (i) a housing arranged to define an internal portion for receiving the liquid to be heated, and (ii) a plurality of electrodes configured to apply electrical energy to the fluid in the internal portion, wherein the plurality of electrodes comprises a first electrode (111) and a second electrode (112) that are capacitively arranged; applying electrical energy to the first electrode (111) to charge the capacitor provided by the first and second electrodes (111; 112) to generate one or more plasma bubbles in the fluid in the inner portion (125); generating heat in the shell near the inner portion in response to the shell receiving incident photons associated with plasma bubbles in the inner portion; use the casing to conductively heat the fluid in the internal portion. 15. A computer program product comprising computer program instructions configured to control the heating system according to any of claims 1 or 3 to 12 to carry out the procedure according to claim 13. 16. A computer program product comprising computer program instructions configured to control the heating system according to any of claims 2 to 12 to carry out the procedure according to claim 14.