Bitumen extraction from oil sands with frequency-controlled heating elements

Abstract

A system powers a heating element with switched direct current (DC) power. The high-speed switching of the heating element triggers lattice excitation in the element alloy, heating up the element. Multiple heating elements heat up a plate on which oil sands can be deposited. The heated plate heats up the oil sands, allowing the bitumen to flow away from the sand.

Description

BITUMEN EXTRACTION FROM OILSANDS WITH FREQUENCY-CONTROLLEDHEATING ELEMENTSCLAIM OF PRIORITY

[0001] The present application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 653,038, filed May 29, 2024, the entire contents of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] Descriptions are generally related to heating systems, and more particular descriptions are related to a heating element system for bitumen extraction from oil sands.BACKGROUND OF THE INVENTION

[0003] Oil sands (or tar sands) is a soil mixture or loosely consolidated sandstone that has sand soaked with bitumen. The soil mixture typically includes water and clay with the sand and bitumen. Bitumen is an oil product that has high viscosity at normal temperatures and pressures, preventing it from flowing.

[0004] Bitumen extraction is typically performed by pumping heated water into the sands. Providing sufficient heat can raise the temperature of the mixture to temperatures between 400-600 C, lowering the viscosity of the bitumen sufficiently to allow it to flow with the water. The sand and soil settles, while the water and bitumen can be pumped out.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The following description includes discussion of figures having illustrations given by way of example of an implementation. The drawings should be understood by way of example, and not by way of limitation. As used herein, references to one or more examples are to be understood as describing a particular feature, structure, or characteristic included in at least one implementation of the invention. Phrases such as "in one example" or "in an alternative example" appearing herein provide examples of implementations of the invention, and do not necessarily all refer to the same implementation. However, they are also not necessarily mutually exclusive.

[0006] FIG. 1 is a block diagram of an example of a system that charges a heating element with a switched DC source.

[0007] FIG. 2 is a diagrammatic representation of an example of changing maximum power point tracking behavior based on a change of impedance in the load.

[0008] FIG. 3A is a block diagram of an example of a controller for a system that charges a heating element with a switched DC source.

[0009] FIG. 3B is a block diagram of an example of a heating system that selects between DC sources.

[0010] FIGs. 4A-4B are circuit representations of examples of a system that switches a DC source.

[0011] FIG. 5 is a flow diagram of an example of powering a heating element.

[0012] FIGs. 6A-6B are representations of examples of phonon lattice vibration.

[0013] FIGs. 7A-7B are line diagrams of an example of a heating element.

[0014] FIG. 7C is a line diagram of an example of a frequency-controlled heating element.

[0015] FIG. 8 is a representation of an example of a temperature response of a heating element material.

[0016] FIG. 9A is a block diagram of an example of a system to extract bitumen from oil sands filtered through a mesh surface heated with a frequency-controlled heating element.

[0017] FIG. 9B is a block diagram of an example of a system to extract bitumen from oil sands filtered through a surface heated with a frequency-controlled heating element.

[0018] FIG. 10A is a block diagram of an example of a heated plate heated by a frequency- controlled, horizontally-mounted heating element.

[0019] FIG. 10B is a block diagram of an example of a heated plate heated by a frequency- controlled, vertically-mounted heating element.

[0020] FIG. 10C is a block diagram of an example of a heated plate heated by a frequency- controlled, horizontally-mounted heating element with a heating reservoir.

[0021] FIG. 10D is a block diagram of an example of a heated plate heated by a frequency- controlled, vertically-mounted heating element with a heating reservoir.

[0022] FIG. 11 is a block diagram of an example of a heated plate heated by a frequency- controlled, top-mounted, vertically-mounted heating element with a heating reservoir.

[0023] FIG. 12A is a block diagram of an example of a heated plate with a grate to allow heated fluid to pass through.

[0024] FIG. 12B is a block diagram of an example of a heated plate with an edge to allow heated fluid to pass off it.

[0025] FIG. 13 is a block diagram of an example of a system to heat a plate via a heat exchanger.

[0026] Descriptions of certain details and implementations follow, including non-limiting descriptions of the figures, which may depict some or all examples, and well as other potential implementations.DETAILED DESCRIPTION OF THE INVENTION

[0027] As described herein, a system provides low-voltage, low-power heating, which can heat oil sands to temperatures sufficient to cause the bitumen to flow. The heating elements in the system can heat a plate on which the oil sands are deposited. The oil sands heat up from the plate, and the bitumen can flow, enabling extraction, without the need to pump heated water. Alternatively, the heating elements can be used to heat the water used in the bitumen extraction process.

[0028] The heating element is made of or composed of an alloy of iron, aluminum, chromium, and nickel. A control circuit charges the heating element with switched DC (direct current) power. The high-speed switching of the heating element triggers lattice excitation in the element alloy, heating up the element. The switching can occur at approximately 10 kHz (kilohertz). Alternatively, the controller can switch the DC power at a frequency greater than 10 kHz, in the range of tens of kilohertz. To a DC system, the high-speed / high-frequency switching appears to be a DC signal, seeing that the system does not react to the fluctuations in voltage since they happen fast enough that the drop in voltage does not significantly alter the performance of the load components.

[0029] In one example, the switching is a DC chop of a current waveform. The system can change the duty cycle of the current waveform based on impedance matching, to maximize power transfer from the DC source to the heating element. The system can change the duty cycle of the high frequency current signal to maintain a substantially constant ratio between a peak output voltage and an average output current. The application of the switched current to the metal lattice of the heating element provides phonon excitation of the lattice structure. Thus, the heating effect can be referred to as electron excitation or lattice excitation.

[0030] The heating element can be used alone or in combination with additional heating elements. The heating element can be used for water heating (e.g., water heaters, spas / hot tubs, swimming pools), oil heating (e.g., enclosed oil-based heaters), space heating, or otherheating applications. In one example, the heating element can be used to heat a system that extracts bitumen from oil sands.

[0031] In one example, the heating element(s) heat a plate directly, which then heats up the oil sands. In one example, the heating element(s) heat up a medium (e.g., water, oil, salt), which heats up the plate, which then heats up the oil sands. The heating of the medium can be in a reservoir that is against the plate (e.g., under or overthe plate). The heating of the medium can be through a heat exchange unit, such as a radiator, that pumps the heated medium under or through the plate.

[0032] FIG. 1 is a block diagram of an example of a system that charges a heating element with a switched DC source. System 100 represents an application of a heating element that generates heat based on lattice excitation. The application in system 100 is bitumen extraction.

[0033] System 100 includes heated plate 130, which is heated with solar heater 132.System 100 illustrates solar cells 110, which represent parallel solar panels that provide solar energy used to heat solar heater 132. System 100 includes controller 120 to convert the energy from solar cells 110 to a switched DC signal to charge solar heater 132.

[0034] In one example, solar heater 132 represents a heating element (e.g., an element having a 1 ohm (Q) resistance). Solar heater 132 is a low impedance, low power heating element. In one example, solar heater 132 has a maximum of approximately 1.3 ohms of resistance, and can be designed to ideally have 1.0 ohms at a DC control current.

[0035] In one example, solar heater 132 is made up of a material that heats up in response to a constant fluctuation of electrons. It will be understood that a metal will heat up in response to a direct current. However, solar heater 132 does not use joule heating as its primary heating operation.

[0036] With joule heating, also referred to as resistive heating, solar heater 132 would produce heat proportional to the current and the resistance. Instead of simply providing joule heating, solar heater 132 has a structure that responds to high speed switching of the DC input power. More specifically, controller 120 generates a switched current signal, where the voltage can be equal to the voltage of output of solar cells 110.

[0037] In one example, controller 120 can use two transistors in parallel on complementary gates to generate two signals switched at high frequency. Controller 120 can generate the two signals without the need for transformers used in traditional switched power sources. The high speed switching to control the solar output can allow the energy to be dispatchable bycontrolling how the energy is applied to the circuit that receives it. The two complementary signals can be combined into a single signal output by controller 120 to power solar heater 132.

[0038] In one example, the high speed switching is accomplished with a DC chopper circuit, modulating a DC current signal with a PWM (pulse width modulator) circuit. System 100 represents switched signal 122 and complementary switched signal 124 in controller 120. It will be understood that the signals shown in controller 120 do not necessarily mean that the power flows through the controller, but that the controller shapes the power or energy available in the illustrated signals.

[0039] System 100 can include other circuit elements not specifically illustrated, which will shape the energy signals to heat the water heater. Signal 126 represents the switched and shaped signal applied to charge solar heater 132.

[0040] In one example, controller 120 can change the duty cycle of the switching of the current signal based on monitoring and detecting a change in impedance matching between solar cells 110 and solar heater 132. In one example, system 100 also includes temperature controls, and can turn off the heating element in response to an over temperature condition of the water, controller 120, or a combination.

[0041] In one example, heated plate 130 represents a plate that can be heated to temperatures sufficient to reduce the viscosity of bitumen to remove it as a flowing liquid from the oil sands. Heating the oil sands mixture can allow the bitumen to flow out of the mixture.

[0042] By using a lower voltage, solar heater 132 would not be subject to the restrictions and regulations as the signals at grid voltage. Additionally, rather than converting the energy into AC, the energy can be applied in a pseudo-DC manner, resulting in higher efficiency heating.

[0043] Diagram 102 represents a sequence of switching that controller 120 can provide to solar heater 132. Diagram 102 illustrates operation 142, which is heating up solar heater 132 when there is a mid-level solar irradiance on solar cells 110. The sequence of signals illustrates a DC current signal that is chopped at a selected duty cycle for impedance matching. As illustrated under the sequence of signals, the period of the signal portion of operation 142 represents the switching frequency (e.g., 10 kHz) at a 50% duty cycle, for a mid-level solar irradiance condition.

[0044] Instead of using table-based MPPT (maximum power point tracking) for maximum power transfer, system 100 can monitor the impedance matching through feedback. Bymonitoring current and voltage, if there is a change in voltage of signal 126, controller 120 can adjust the duty cycle to adjust the impedance matching.

[0045] It will be understood that maximum power is transferred when all power available from solar cells 110 is transferred to the heating element. If the power transfer circuitry does not regulate the input voltage, the maximum power can be transferred at the input voltage. The output current can be adjusted based on adjusting the duty cycle of the current signal. Thus, the current perceived at the output, and received at solar heater 132, will be the weighted average of the switched current signal. By controlling the current signal, system 100 operates in current mode rather than in voltage mode.

[0046] Diagram 102 illustrates operation 144, which is heating up solar heater 132 when there is a high-level solar irradiance on solar cells 110. The high-level solar irradiance can approach the highest output of the solar cells, for example, in the range of 1300 W / mA2, or whatever is supported by the solar cells. As illustrated under the sequence of signals, the period of the signal portion of operation 144 represents the switching frequency at an 87.5% duty cycle, for a high-level solar irradiance condition. In one example, the duty cycle can be as high as 98% for maximum solar irradiance.

[0047] Diagram 102 illustrates operation 146, which is heating up solar heater 132 when there is a low-level solar irradiance on solar cells 110. The low-level solar irradiance can approach the lowest output of the solar cells, for example, in the range of 200 W / mA2, or whatever is supported by the solar cells. As illustrated under the sequence of signals, the period of the signal portion of operation 146 represents the switching frequency at a 12.5% duty cycle, for a low-level solar irradiance condition. In one example, the duty cycle can be as low as 2% for minimum solar irradiance.

[0048] In one example, heating system can include the heating element and the controller, which can together be considered a water heating system or a controller / controller system to heat liquid. Controller 120 does not specifically illustrate the power converter circuit that is / includes the switching circuit. Examples are provided below.

[0049] As indicated in diagram 102, the output of controller can be a high frequency chopped current signal with varying duty cycle. In one example, solar heater 132 is 1 ohm, providing very low resistance. The voltage output of the solar panels can be on the order of 35 V or 40 V. With low voltage and 1 ohm impedance, it will be understood that the current input to the heating element will be relatively high.

[0050] Consider a system having solar cells 110 that generate an output at 36 VDC, and up to 1200 W. With 1.0 ohms of resistance, the current will necessarily flow at over 30 amps, since P=VI, where V=IR, and thus, P=(IA2)*R, meaning the current is l=sqrt(P / R)=sqrt(P) when R=l. In one example, system 100 operates at a maximum of approximately 36 A at 36 V.

[0051] FIG. 2 is a diagrammatic representation of an example of changing maximum power point tracking behavior based on a change of impedance in the load. In one example, the controller of system 100 performs MPPT (maximum power point tracking) to convert the energy from the PV source to the switched DC signal.

[0052] Diagram 200 illustrates two curves, curve 210 and curve 220, plotted as current 202 versus voltage 204. Curve 210 represents a portion of the non-linear voltage-current (V-l) characteristic behavior of a solar cell / PV source. The V-l characteristic curve can alternatively be referred to as the power characteristic curve or power curve. Curve 220 represents a plot of the current times the voltage of curve 210. It will be understood that diagram 200 is not intended to show the entire V-l curve (e.g., the x-axis and y-axis may not start at '0'), but rather a portion near the "knee" of the power curve where the MPP (maximum power point) is found.

[0053] Diagram 200 illustrates a portion of the curves to highlight the differences discussed below. It will be understood that diagram 200 is not necessarily to scale, and different PV sources can have different characteristic curves. It will also be understood that the general shape of the curves can be generally representative of PV (photovoltaic) sources.

[0054] Typical power curves extend from the short circuit current (Isc) on the y-axis to the open circuit voltage (Voc) on the x-axis. To further illustrate that diagram 200 illustrates does not necessarily cover the entirety of curve 210, curve 210 extends from IREF to VREF, which are respective current and voltage points at the axes illustrated.

[0055] Diagram 200 illustrates IPMAX-I, which intersects with VPMAX-I on curve 210 at impedance match 232. IPMAX-I represents a current for the MPP, which corresponds to VP AX-I- It will be observed that MPP intersects the apex of curve 220. It will be understood that the MPP tends to change based over time based on changing conditions, such as illumination level, panel temperature, panel age, cleanliness of the panel, and other conditions. As the conditions change, the knee of curve 210 will change, and the corresponding curve 220 will change.

[0056] MPPT algorithms track the MPP as it changes with changing conditions. However, it will be understood that MPPT algorithms expect to match a particular condition. Namely, MPPT tracks the MPP assuming a constant impedance to be matched. While the algorithms track forchanges in the conditions of the panels, the output will not result in the highest efficiency energy transfer when the impedance to be matched does not match the expectations of the MPPT algorithm. Furthermore, MPPT algorithms traditionally operate on "tables" of information due to the assumptions being made, and finding a measured value and setting a value from the table based on it.

[0057] The controllers described herein can perform MPPT with adjustment for a change to the impedance matching, whether the solar cells output different power amounts or the impedance of the heating element changes in different conditions.

[0058] Diagram 200 illustrates impedance match 234, which represents a theoretical place on curve 210 that provides accurate impedance matching with the load. Thus, while impedance match 232 can represent impedance match 232 as an ideal impedance match based solely on the conditions and characteristics of the solar panel / solar array, impedance match 234 represents the ideal impedance match based on a change to resistance of the load based on changes in system operation.

[0059] Thus, the intersection of IPMAX-2 with VPMAX-2 on curve 210 at impedance match 234 is presented to represent a change to the MPP based on the load conditions. IPMAX-2 represents a current for the preferred impedance match point, which corresponds to VPMAX-2- In diagram 200, impedance match 234 would not correspond with the apex of curve 220, but would match up with a curve that is adjusted for the distortion based on the change in load impedance.

[0060] For purposes of a total system view, impedance match 234 can be considered the MPP for the power curve. The system can include an MPPT unit that tracks the MPP for the adjusted power curve as described above.

[0061] FIG. 3A is a block diagram of an example of a controller for a system that charges a heating element with a switched DC source. Controller 310 represents a controller in accordance with an example of system 100. Controller 310 can include a microcontroller, logic array, a control board, processor, or other component.

[0062] Controller 310 either includes or controls a power converter circuit that generates and transfers the energy from a DC energy source to a heating element in accordance with any example herein. Converter 320 represents the power converter circuit. Converter 320 includes switching circuit 322 to switch DC power (more specifically, the current signal of the power) from the DC energy source to the heating element. In one example, switching circuit 322 is controlled by control signals provided by controller 310. In one example, the signals thatcontrol switching circuit 322 can be considered to be provided by control circuitry separate from controller 310, and can be part of converter 320.

[0063] MPPT 312 represents a maximum power point tracking unit of controller 310. The operation of MPPT 312 enables controller 310 to track the maximum power point based on conditions of the PV source as well as based on changing impedance of the load due to temperature changes.

[0064] Feedback 314 represents control logic in controller 310 to enable the controller to receive feedback information to monitor changing conditions in the system. For example, and specifically for purposes of what is described herein, feedback 314 can enable controller 310 to receive and respond to changes in power received at the heating element, which changes the impedance matching. In response to changes in conditions that affect impedance matching, controller 310 can adjust the switching of switching circuit 322 to change the duty cycle, providing better impedance matching between the power generated from the energy source and the heating element.

[0065] It will be understood that controller 310 does not include an inverter, nor does the controller operate with an inverter. Rather, the system can simply provide high speed switching of the current to heat up the heating element, while maintaining a low voltage. In one example, the solar heating element and the controller are not connected to the power grid. Rather, the system simply includes solar cells that are connected to the heating element, without connecting the heating element to the grid, or passing through any circuitry that connects power from the solar cells to the grid. In one example, Not connected to the grid.

[0066] FIG. 3B is a block diagram of an example of a hybrid water heating system that selects between DC sources. System 302 represents a system in accordance with an example of system 100. System 302 alternatively represents the control in the system as control circuit 350. Alternatively, control circuit 350 can be referred to as "the electronics," referring to the electronic control components that manage the operation of the system. Control circuit 350 can include a microcontroller, logic array, a control board, processor, or other component. In one example, control circuit 350 represents an example of controller 310.

[0067] Solar 330 represents a solar panel or multiple panels in parallel to provide PV energy for system 302. Energy source 340 represents an alternate energy source, such as an energy storage device or other non-solar source of power that can provide power to control circuit350. In one example, control circuit 350 can include multiplexer (mux) 352 to select between solar 330 and energy source 340.

[0068] Converter 354 represents converter hardware that enables control circuit 350 to convert energy from the selected source to generate a switch DC signal. Converter 354 provides the switched DC power to heating element 362 of heating system 360 in accordance with any example herein. Heating system 360 represents any type of heating system that utilizes heating elements in accordance with any example herein.

[0069] FIG. 4A is a circuit representation of an example of a system that switches a DC source. System 402 can represent converter hardware to power a heating element in accordance with any example herein.

[0070] System 402 includes a node to receive input voltage, VIN 412. VIN 412 can be filtered or conditioned with filter 422, which represents circuitry that can filter and shape the input signal. Inductor 432 represents a magnetic energy storage device that controls the input impedance of the signal. Capacitor 442 represents output energy storage to charge and hold the output voltage to form the switched output.

[0071] Switch 460 represents any type of switching circuitry to perform high-speed switching of the DC signal. The high-speed switching generates a high frequency signal with a frequency at least an order of magnitude higher than a typical grid AC power signal. In one example, system 402 provides a switched DC current.

[0072] Controller 452 represents control logic, such as provided by a controller device, to control the switching of switch 460. In one example, controller 452 controls the switching of switch 460 through a pulse width modulator signal. System 402 provides the switched output signal to load 472, which can be a heating element or battery in accordance with any example herein.

[0073] FIG.4B is a circuit representation of an example of a system that switches a DC source. System 404 can represent converter hardware to power a heating element in accordance with any example herein.

[0074] System 404 includes a node to receive input voltage, VIN 414. VIN 414 can be filtered or conditioned with filter 424, which represents circuitry that can filter and shape the input signal. Inductor 434 represents a magnetic energy storage device that controls the input impedance of the signal. Capacitor 444 represents output energy storage to charge and hold the output voltage to form the switched output.

[0075] Transistor 470 represents any type of transistor or transistor-based driver circuitry to perform high-speed switching of the DC signal. In one example, transistor 470 is a high power MOSFET (metal-oxide-semiconductor field effect transistor). In one example, system 404 includes multiple power MOSFETs in parallel to provide higher current capability to system 404. The high-speed switching with the transistors generates a high frequency signal with a frequency at least an order of magnitude higher than a typical grid AC power signal. In one example, system 404 provides a switched DC current.

[0076] Controller 454 represents control logic, such as provided by a controller device, to control the switching of transistor 470. In one example, controller 454 controls the switching of transistor 470 through a PWM (pulse width modulator) signal. PWM 456 represents a PWM generator in controller 454. System 404 provides the switched output signal to load 474, which can be a heating element or battery in accordance with any example herein.

[0077] FIG. 5 is a flow diagram of an example of powering a heating element. Process 500 represents a process to provide energy to a heating element in accordance with any system described. In one example, the system controller selects a PV power source as the source for energy to charge the heating element, at 502.

[0078] In one example, the controller performs MPPT to determine the maximum power for the PV power source, at 504. By knowing the maximum power, the system can monitor and adjust the impedance matching through switching the output current. In one example, the MPPT tracks the maximum impedance matching point of the system, even when the resistive load changes for the heating element, and even in changing light conditions for the PV power source. With a frequency selected based on the MPP found by MPPT, the system can charge the heating element by switching power from the PV power source at a high frequency, at 506.

[0079] The controller can monitor the impedance matching between the PV power source and the heating element with a feedback loop, at 508. If the impedance match is good, at 510 YES branch, the controller can continue to monitor the impedance matching, at 508.

[0080] If the controller detects a degradation of the impedance matching, at 510 NO branch, in one example, the controller adjusts a duty cycle of the output current to match impedance between the solar source and the heating element, at 512. The controller can then cause the converter hardware to charge the heating element with the newly selected duty cycle, at 506.

[0081] FIG. 6A is a representation of an example of phonon lattice vibration in two dimensions. Lattice 602 represents a metallic lattice for a heating element in accordance with any example herein. The different atoms are not specifically identified in the lattice structure, but the metal alloy is an Fe-Cr-AI-Ni alloy (an alloy of iron, chromium, aluminum, and nickel).

[0082] It will be understood that a metal alloy has atoms of different metal types held in a structure with metallic bonds. Such a solid consists of closely packed atoms. In metals, the electrons of the outermost electron shell of the metal atoms do not stay local to their originating atom. Rather, the electrons of the outermost shell are nonlocalized, overlapping with neighboring atoms, allowing the electrons to move freely throughout the metal crystal.

[0083] The circles represent positions of the alloy atoms. The lighter color circles represent lattice positions 612, which are the lattice positions of the atoms when the metal is at rest, in a non-excited state. The darker circles represent displaced positions 614, which are the lattice positions at an instant in time when a phonon has excited the lattice structure.

[0084] It will be observed that the phonon excites the atoms as a wavefunction propagating through the lattice structure, displacing atoms in accordance with the wave energy of the phonon. Thus, at any given instant, some atoms will be displaced farther than others. Displacement overlap 624 illustrates an atom in lattice 602 that in a moment in the phonon wave will occupy the same position it would be in if the lattice were undisturbed. Phonon displacement 622 illustrates the distance between a position a different atom would occupy in the undisturbed lattice compared to the position it occupies in the moment of phonon propagation through lattice 602 that is illustrated. A short time difference (At) later, the displacement of the atoms will have changed as the phonon propagates through the lattice.

[0085] In lattice 602, the distance 610 can represent the wavelength (A.) of the phonon. It will be understood that different atomic structures will respond differently to different phonon wavelengths. The lattice of the alloy described can have a different resonant frequency compared to other metallic structures. Application of a phonon in a band of frequencies close to the lattice resonant frequency can improve the transfer of energy through phonon excitation.

[0086] The structure of the alloy enables the conversion of solar energy into heat energy through phonon excitation of the lattice structure. Instead of joule heating, the control circuit powers the heating element with a high frequency signal to cause the lattice structure to "ring". Experimentation with the alloy described and the controller described has demonstrated to theinventors that the structure resonates with phonon excitation when powered from the PV source.

[0087] Experimentation has also demonstrated to the inventors that the heating of the water occurs with increases in efficiency as compared to joule heating under similar conditions. Applying the switched power to a 1 ohm heating element (made of Fe-Cr-AI) in the same configuration described yielded energy transfer to water heating in accordance with what is expected by joule heating equations. However, applying the switched power to a 1 ohm heating element in accordance with what is described herein, with an Fe-Cr-AI-Ni alloy structure, yielded energy transfer up to 30% more efficiently than the use of traditional joule heating.

[0088] The inventors have concluded that heating through phonon excitation of the lattice can provide more efficient heating than joule heating. The inventors have observed that the efficiency of the phonon excitation appears to be at its peak when the solar irradiance on the solar panels is low. It is suspected that the heating capacity of the element does not increase with the increased current from the solar panels because the increase in the current injects more energy into the lattice. The increase in energy may create a hot-phonon bottleneck, where the lattice is not able to fully relax to its default structure between phonon wave maxima. Thus, the increase in current may dampen the oscillation of the lattice structure, limiting the ability to convert additional energy to heat.

[0089] At the same time, the inventors suspect that the structure of the alloy with the introduction of the nickel improves the alloy's ability to convert solar energy into heat energy. Analysis of the outermost electron shells of the component metals reveals the following:

[0090] Fe has a structure of [Ar] 4s2 3d6, with a full 4s orbital, and one more electron in the 3d orbital than the relatively stable 3d5 state (all five d orbitals have a single electron), which is one electron more than the nearest stable state;

[0091] Cr has a structure of [Ar] 4sl 3d5, with a single electron in the 4s orbital, in favor of the relatively stable 3d5 state, which is one electron more than the nearest stable state; however, such a structure has the effect of reducing the conductivity of the 4s electron due to interference from the 3d orbitals;

[0092] Al has a structure of [Ne] 3s2 3pl, with a full 3s orbital, and one electron in the outer 3p orbital, which is one electron shy of the nearest stable state.

[0093] It is thus assumed that Fe-Cr-AI (known as KANTHAL) has Fe with +1, Cr with +1, and Al with -1, for an alloy that generally has a +1 electron carrier outer shell.

[0094] Ni has a structure of [Ar] 4s2 3d8, with a full 4s orbital, and two electrons missing from a stable 3d orbital (all five d orbitals having two electrons), which is two electrons low from the nearest stable state. Thus, it is assumed that Ni has a -2 electron carrier outer shell. The inventors thus believe that adding nickel to the alloy to make Fe-Cr-AI-Ni results in a metal which is hole dominant, with one electron shy in the outer shell, thus being a -1 electron carrier outer shell. For this reason, the inventors suspect that structure receives electrons well while still being very susceptible to phonon vibration propagation through the structure.

[0095] It will be understood that if the inventors' analysis is incorrect, the alloy composition driven by the switched frequency current signal still performs as has been observed and indicated herein.

[0096] FIG. 6B is a representation of an example of phonon lattice vibration in three dimensions. Lattice 604 represents an example of a lattice in accordance with lattice 602. Distance 630 represents a phonon wavelength in accordance with distance 610 of lattice 602. In addition to the two-dimensional displacement identified for lattice 602, it will be understood that the phonon wave can propagate through the alloy between layers of atoms, as illustrated by phonon displacement 632.

[0097] FIG. 7A is a line diagram of an example of a heating element. Heating element 702 illustrates a heating element in accordance with any example herein. The view illustrated is a "packaged" view of the heating element. Heating element 702 is a frequency-controlled heating element.

[0098] In one example, heating element 702 has interface 710 with threading 720, which can allow the heating element to be screwed into a heating element socket of a water heater. For applications outside of a water heater, interface 710 can be designed to interface with the specific application.

[0099] Heating element 702 includes rod 730, which represents an outer cover for the heating element, with the Fe-Cr-AI-Ni material encased inside rod 730. In one example, rod 730 is a simple steel casing. Other materials can be used that have good heat transfer properties. Any number of materials can work for rod 730, but steel has sufficient properties while being relatively inexpensive.

[0100] Lead 1 and Lead 2 carry the power and ground connections through the control circuit board and to the solar power source. The leads connect between the heating element in rod 730.

[0101] FIG. 7B is a circuit representation of an example of the heating element of FIG. 7A. Heating element 704 is illustrated as a cutaway view, seeing inside interface 710 and inside rod 730.

[0102] Element 732 can be referred to as the excitation element, being the Fe-Cr-AI-Ni alloy material. The gauge and length of element 732 can be controlled to make the length of wire from Lead 1 to Lead 2 to be as close as possible to 1.0 ohms. The resistivity of the material is controlled, and does not change significantly for the range of temperatures of the intended use of the element.

[0103] Since the heating element is designed to be as close as possible to 1.0 ohms over the operating temperature of the device, changes in current will not significantly change the resistivity. Thus, heating element 704 is controlled by frequency rather than current. Similarly, changes in voltage will not significantly change the resistivity. Thus, heating element 704 is controlled by frequency rather than voltage. The heating element can be controlled by the switching frequency rather than current or voltage.

[0104] In one example, element 732 is made of solid 6 gauge, 8 gauge, 10 gauge, or 12 gauge wire wound into the classic heating element coil shape. In one example, the coil of element 732 is relatively loose, as a tighter coil would increase the inductance of the heating element, which can increase the impedance of the high frequency current delivered through the leads.

[0105] In one example, rod 730 is filled with a ceramic powder. In one example, in place of a ceramic powder, another potting material can be used. The ceramic can be selected to be non-conductive and a good conductor of heat. Thus, element 732 heats up, which heats up ceramic 734 and in turn, heats up rod 730. Depending on the application for heating element 704, rod can be steel, nichrome, cupronickel, or some other material.

[0106] In one example, rod 730 has a length represented by length 744 and a width (diameter) represented by diameter 742. The length can be selected based on the gauge of the wire and the coiling of element 732. The width can similarly be affected by the gauge of the wire and how it is coiled.

[0107] In one example, ceramic 734 operates as a heat-storage component for heating element 704. The heat conductivity of the ceramic can allow for some heat retention by the ceramic, maintaining a fairly constant heat environment for element 732. In one example, the resistivity of element 732 is slightly less than 1.0 ohms, and when the element begins to heatup, ceramic 734 can provide heat retention to raise the resistivity to approximately exactly 1.0 ohms.

[0108] Lead 1 and Lead 2 carry the power in a circuit loop from the PV panel, through element 732, and back to PV ground. In one example, element 732 is specifically designed to connect to the leads with some gap into rod 730. Since element 732 heats up, having the leads extend some distance into rod 730 before connecting to the element can reduce the transfer of heat to interface 710. In one example, interface 710 is potted with insulator 712 to reduce the transfer of heat up into interface. The control circuit (not specifically shown) accelerates the electrons from the panel by creating the high frequency current signal to drive the material.

[0109] FIG. 7C is a I ine diagram of an example of a frequency-controlled heating element. Heating element 706 provides an example of a heating element in accordance with heating element 702, where heating element 706 is specifically shown shorter and wider than what is illustrated for heating element 702. Heating element 706 is illustrated as a cutaway view, seeing inside interface 750 and inside rod 760.

[0110] Element 762 can be referred to as the excitation element, being the Fe-Cr-AI-Ni alloy material. The gauge and length of element 762 can be controlled to make the length be as close as possible to 1.0 ohms. In one example, element 762 is made of solid wire (6 gauge, 8 gauge, 10 gauge, or 12 gauge) wound into the classic heating element coil shape. In one example, the coils of element 762 are closer together than the coils of element 732, but with larger loops.Controlling the coil for inductance can reduce the change in impedance in response to high frequency current delivered through the leads.

[0111] In one example, rod 760 is filled with a ceramic powder. Potting 764 represents the ceramic powder or other potting material that is selected to be non-conductive and a good conductor of heat. Thus, element 762 heats up, which heats up potting 764 and in turn, heats up rod 760. Depending on the application for heating element 706, rod can be steel, nichrome, cupronickel, or some other material.

[0112] In one example, rod 760 has a length represented by length 774 and a width (diameter) represented by diameter 772. The length can be selected based on the gauge of the wire and the coiling of element 762. The width can similarly be affected by the gauge of the wire and how it is coiled. Rod 760 is shown with a shorter length and a wider diameter than rod 730, illustrating that there can be variations in width and length of the heating element.

[0113] In one example, potting 764 operates as a heat-storage component for heating element 706. The heat conductivity of the ceramic can allow for some heat retention by the ceramic, maintaining a fairly constant heat environment for element 762. In one example, the resistivity of element 762 is slightly less than 1.0 ohms, and when the element begins to heat up, potting 764 can provide heat retention to raise the resistivity to approximately exactly 1.0 ohms.

[0114] Lead 1 and Lead 2 carry the power in a circuit loop from the PV panel, through element 762, and back to PV ground. In one example, element 762 is specifically designed to connect to the leads with some gap into rod 760. Since element 762 heats up, having the leads extend some distance into rod 760 before connecting to the element can reduce the transfer of heat to interface 750. In one example, interface 750 is potted with insulator 752 to reduce the transfer of heat up into interface. The control circuit (not specifically shown) accelerates the electrons from the panel by creating the high frequency current signal to drive the material.

[0115] FIG. 8 is a representation of an example of a temperature response of a heating element material. Diagram 800 illustrates a temperature response of a heating element metal, which can specifically be the metal alloy for the heating elements described herein. In one example, the resistivity does not change significantly with increases in temperature.

[0116] Curve 812 illustrates the temperature response. In one example, curve 812 has bump 814, where at a certain temperature the response is not linear. In much of the rest of the curve, the response can be fairly linear. Not all materials will have such a non-linear bump, but the response can be fairly linearwith increases in temperature.

[0117] While the resistivity may not change significantly with temperature change, there can be some change. With the change in resistivity, the heating element coil can be designed to have a resistivity of slightly less than 1.0 ohms when there is no current through the element. When current goes through and the element heats up, the change in resistivity can raise the impedance of the heating element to be approximately 1.0 ohms.

[0118] FIG. 9A is a block diagram of an example of a system to extract bitumen from oil sands with a frequency-controlled heating element. System 902 illustrates heating units 920, which are frequency-controlled heating elements. System 902 has heating surface and opening 932 (hereafter "surface 932"). Surface 932 represents a surface heated by heating units 920.

[0119] Oil sands 910 represents oil sands, which have bitumen mixed in with sand. In one example, surface 932 has an opening, such as a grating or other opening that allows heatedfluid 940 to pass through while the sand remains on the surface. Heat bitumen 950 represents the flow of heated fluid that has passed through or off of surface 932.

[0120] In one example, surface 932 is a surface with small openings in the surface. Such openings can be square, rectangular, or diamond shaped. In one example, the surface is a metal plate with cutouts in it. In one example, the surface is formed as a mesh that creates such openings, where the mesh interfaces with a more solid metal or heat transfer part that is heated by heating units 920. The heating by heating units 920 on the edges can raise the temperature on the plate to temperatures sufficient to allow the bitumen to flow.

[0121] It will be understood that a mesh could allow significant amounts of the sand to flow through with the bitumen. In one example, the openings are very small to reduce the amount of sand that flows through with the bitumen. In one example, system 902 is a first heating stage, where another heating stage can be positioned directly under system 902 to improve the filtering of the bitumen from the oil sands.

[0122] In one example, surface 932 has a width of hundreds of feet, allowing trucks to dump an entire load of oil sands on the heated surface. Heating units 920 heat surface 932 to hundreds of degrees Celsius. Placing oil sands 910 on the heated surface can raise the temperature of the oil sands mixture to a high enough temperature to liquify the bitumen in the oil sands, causing it to flow. The flowing bitumen is heated fluid 940, which can run through the opening through or off surface 932.

[0123] FIG. 9B is a block diagram of an example of a system to extract bitumen from oil sands with a frequency-controlled heating element. System 904 illustrates heating units 920, which are frequency-controlled heating elements. System 904 has heating surface and opening 934 (hereafter "surface 934"). Surface 934 represents a surface heated by heating units 920.

[0124] Oil sands 910 represents oil sands, which have bitumen mixed in with sand. In one example, surface 934 has an opening, such as holes or other opening that allows heated fluid 940 to pass through while the sand remains on the surface. Heat bitumen 950 represents the flow of heated fluid that has passed through or off of surface 934.

[0125] In one example, surface 934 is a surface with small openings in the surface. Such openings can be circular or oval shaped. In one example, the surface is formed as cutouts in a metal plate, heating units 920 can heat the edges of the plate, which then spreads heat through the whole plate. The heating by heating units 920 on the edges can raise the temperature on the plate to temperatures sufficient to allow the bitumen to flow.

[0126] It will be understood that the openings could allow significant amounts of the sand to flow through with the bitumen. In one example, the openings are very small to reduce the amount of sand that flows through with the bitumen. In one example, system 904 is a first heating stage, where another heating stage can be positioned directly under system 904 to improve the filtering of the bitumen from the oil sands.

[0127] In one example, surface 934 has a width of hundreds of feet, allowing trucks to dump an entire load of oil sands on the heated surface. Heating units 920 heat surface 934 to hundreds of degrees Celsius. Placing oil sands 910 on the heated surface can raise the temperature of the oil sands mixture to a high enough temperature to liquify the bitumen in the oil sands, causing it to flow. The flowing bitumen is heated fluid 940, which can run through the opening through or off surface 934.

[0128] FIG. 10A is a block diagram of an example of a heated plate heated by a frequency- controlled, horizontally-mounted heating element. System 1002 illustrates plate 1010 heated by frequency-controlled heating elements. The heating elements are mounted horizontally to a surface of plate 1010. As illustrated, the heating elements are mounted to the bottom surface of plate 1010. Alternatively, the heating elements could be mounted to the top surface of plate 1010.

[0129] Rods 1012 represent frequency-controlled heating elements. In one example, rods 1012 represent heating elements mounted into holes or tubes directly in plate 1010. Rods 1014 represent frequency-controlled heating elements. In one example, rods 1014 represent heating elements mounted into structures 1022, which are mounted (such as welded or bolted) to plate 1010. Reference to mounting the structures to the plate refers to the structures being attached or adhered to the plate to enable the transfer of heat from the structure to the plate. The specific shape of structure 1022 can have a cross-section that is square, rectangular, semicircular, half-circle, or some other cross-section.

[0130] In one example, whether referring to rods 1012 directly inserted into plate 1010, or rods 1014 mounted in structures 1022, the rods can be surrounded by a heat transfer material, such as a paste or a ceramic. The paste or ceramic can improve the heat transfer from the outer surface of the rods to the metal structure of plate 1010.

[0131] FIG. 10B is a block diagram of an example of a heated plate heated by a frequency- controlled, vertically-mounted heating element. System 1004 illustrates plate 1030 heated by frequency-controlled heating elements. The heating elements are mounted vertically to asurface of plate 1030. As illustrated, the heating elements are mounted to the bottom surface of plate 1030.

[0132] Rods 1032 represent frequency-controlled heating elements. In one example, rods 1032 represent heating elements mounted into structures 1042, which are mounted to plate 1030. Structures 1042 have a square or rectangular cross-section. Rods 1034 represent frequency-controlled heating elements. In one example, rods 1034 represent heating elements mounted into structures 1044, which are mounted to plate 1030. Structures 1044 have a round or oval cross-section. Besides square, rectangular, round, or oval, the mounting structures can have a cross-section that ais rectangular, semi-circular, half-circle, or some other cross-section.

[0133] In one example, whether referring to rods 1032 mounted in structures 1042, or rods 1034 mounted in structures 1044, the rods can be surrounded by a heat transfer material, such as a paste or a ceramic. The paste or ceramic can improve the heat transfer from the outer surface of the rods to the metal structure of plate 1030.

[0134] FIG. 10C is a block diagram of an example of a heated plate heated by a frequency- controlled, horizontally-mounted heating element with a heating reservoir. System 1006 illustrates plate 1050 heated by frequency-controlled heating elements. The heating elements are mounted horizontally to a surface of plate 1050. As illustrated, the heating elements are mounted to the bottom surface of plate 1050. Alternatively, the heating elements could be mounted to the top surface of plate 1050.

[0135] Rods 1052 represent frequency-controlled heating elements. In one example, rods 1052 represent heating elements mounted into structure 1062, which is mounted to plate 1050. Rods 1054 represent frequency-controlled heating elements. In one example, rods 1054 represent heating elements mounted into structures 1064, which are mounted to plate 1050. The specific shape of structure 1062 or structures 1064 can have a cross-section that is square, rectangular, semi-circular, half-circle, or some other cross-section.

[0136] Structures 1064 represent structures that accommodate a single heating element. Structure 1062 represents a structure that accommodates more than one heating element. Structure 1062 and structures 1064 include an outer structure, such as metal or ceramic that has good capability to transfer heat to plate 1050. In one example, the outer structures have a material with heat insulation on all sides except the one in contact with plate 1050. The side in contact with plate 1050 can have a material with good heat transfer characteristics to transfer heat to the plate.

[0137] Structure 1062 includes a reservoir indicated by fill 1066, which refers to a reservoir of material that surrounds rods 1052. Structures 1064 include reservoirs indicated by fill 1068, which refers to a reservoir of material that surrounds rods 1054. Fill 1066 and fill 1068 can be any material that transfers heat from the heating element to the wall / side of the structure that will heat plate 1050. Examples of material include oil, water, salt (that will become molten in response to heating the element), or other heat transfer material. It will be understood that using a material such as water, which increases in volume when heated, will require structural design to deal with the increased pressure.

[0138] FIG. 10D is a block diagram of an example of a heated plate heated by a frequency- controlled, vertically-mounted heating element with a heating reservoir. System 1008 illustrates plate 1070 heated by frequency-controlled heating elements. The heating elements are mounted vertically to a surface of plate 1070. As illustrated, the heating elements are mounted to the bottom surface of plate 1070.

[0139] Rod 1072 represents a frequency-controlled heating element. In one example, rod 1072 represents a heating element mounted into structure 1082, which is mounted to plate 1070. Structure 1082 has a square or rectangular cross-section. Rod 1074 represents a frequency-controlled heating element. In one example, rod 1074 represents a heating element mounted into structure 1084, which is mounted to plate 1070. Structure 1084 has a round or oval cross-section. Besides square, rectangular, round, or oval, the mounting structures can have a cross-section that ais rectangular, semi-circular, half-circle, or some other cross-section.

[0140] Structure 1082 and structure 1084 represent structures that accommodate a single heating element. In one example, the structures can be modified to hold more than one heating element. Structure 1082 and structure 1084 include an outer structure, such as metal or ceramic that has good capability to transfer heat to plate 1070. In one example, the outer structures have a material with heat insulation on all sides except the one in contact with plate 1070. The side in contact with plate 1070 can have a material with good heat transfer characteristics to transfer heat to the plate.

[0141] Structure 1082 includes a reservoir indicated by fill 1086, which refers to a reservoir of material that surrounds rod 1072. Structure 1084 includes a reservoir indicated by fill 1088, which refers to a reservoir of material that surrounds rod 1074. Fill 1086 and fill 1088 can be any material that transfers heat from the heating element to the wall / side of the structure that will heat plate 1070. Examples of material include oil, water, salt (that will become molten inresponse to heating the element), or other heat transfer material. It will be understood that using a material such as water, which increases in volume when heated, will require structural design to deal with the increased pressure.

[0142] FIG. 11 is a block diagram of an example of a heated plate heated by a frequency- controlled, top-mounted, vertically-mounted heating element with a heating reservoir. System 1100 illustrates plate 1110 heated by frequency-controlled heating elements. The heating elements are mounted vertically to a surface of plate 1110. As illustrated, the heating elements are mounted to the top surface of plate 1110.

[0143] System 1100 illustrates various alternative vertically-mounted heating structures with a heating material reservoir. Specifically, system 1100 illustrates structure 1122 that has a pyramidal cross-section, structure 1132 that has a round or oval cross-section, and structure 1142 that has a rectangular or square cross-section. The structures are all shown as accommodating a single heating element rod; in one example, one or more of the shapes can be adjusted to accommodate multiple heating elements.

[0144] All of the structures include an outer structure, such as metal or ceramic. In one example, the outer structures have a material with heat insulation on all sides except the one in contact with plate 1110. In one example, all sides of the structure are made of the same material. At least the side in contact with plate 1110 has a material with good heat transfer characteristics to transfer heat to the plate.

[0145] Structure 1122 receives rod 1124, which will be in fill 1126, which represents a reservoir of material that will transfer heat from rod 1124, through structure 1122 to plate. Rod 1124 represents a frequency-controlled heating element.

[0146] Structure 1132 receives rod 1134, which will be in fill 1136, which represents a reservoir of material that will transfer heat from rod 1134, through structure 1132 to plate. Rod 1134 represents a frequency-controlled heating element.

[0147] Structure 1142 receives rod 1144, which will be in fill 1146, which represents a reservoir of material that will transfer heat from rod 1144, through structure 1142 to plate. Rod 1144 represents a frequency-controlled heating element.

[0148] Fill 1126, fill 1136, and fill 1146 can be any material that transfers heat from the heating element to the wall / side of the structure that will heat plate 1110. Examples of material include oil, water, salt, or other heat transfer material. It will be understood that usinga material such as water, which increases in volume when heated, will require structural design to deal with the increased pressure.

[0149] FIG. 12A is a block diagram of an example of a heated plate with a grate to allow heated fluid to pass through. System 1202 represents a system in accordance with an example of system herein to heat oil sands to extract bitumen. System 1202 illustrates plate 1210 heated by frequency-controlled heating elements. System 1202 does not specifically illustrate the heating elements, which can be mounted to plate 1210 in accordance with any example described. Plate 1210 can be metal or ceramic.

[0150] In one example, plate 1210 is pitched at angle phi ((D) relative to level, where level refers to an even plane. The angle represents a slope of plate 1210. The slope can generally be thought of as a "downward slope" or "downhill slope", allowing the heated bitumen to flow away from the oil sands. Mounting plate 1210 at a small angle will allow a substance, such as sand, to stay relatively stationary on plate 1210, while a heated liquid, such as heated bitumen, will flow down the plate toward the edge that is lower.

[0151] Toward the lower edge or at the lower edge, plate 1210 can have a grid or grating to allow heated fluid to pass through the plate, while being fine enough that the sand will not generally pass through. Plate 1210 illustrates two different types of gratings, with grid 1212 and grid 1214. Grid 1212 represents round or oval openings in plate 1210. Grid 1214 represents square or rectangular openings. In one example, grid 1212 or grid 1214 represents a grating, with cross-mounted pieces or strips of metal or ceramic that forms small openings.

[0152] In operation, plate 1210 can be heated many hundreds of degrees Celsius (e.g., in a range of 800-1300 C) by the frequency-controlled heating elements. Plate 1210 can have dimensions that are dozens of feet in length and many hundreds of feet in width, such a size enabling a truck to directly dump a full load of oil sands onto the heated plate. When the oil sands land on plate 1210, the temperature of the plate will drop by several hundred degrees. The temperature can be managed to still be high enough to cause the bitumen in the sand to have a high enough viscosity to flow down plate 1210. The heated bitumen can then flow through the grate while leaving the sand on the plate.

[0153] After sufficient time to allow the bitumen to be extracted from the sand, the sand can be moved across the plate, and eventually off the plate. Moving the sand off the plate can make more room to deposit additional oil sands for bitumen extraction. The extraction can occur without the use of water and through the use of solar heating of the heating elements,which in turn heat the plate. Thus, the bitumen can be extracted with little or no water using renewable energy.

[0154] FIG. 12B is a block diagram of an example of a heated plate with an edge to allow heated fluid to pass off it. System 1204 represents a system in accordance with an example of system herein to heat oil sands to extract bitumen. System 1204 illustrates plate 1220 heated by frequency-controlled heating elements. System 1202 does not specifically illustrate the heating elements, which can be mounted to plate 1220 in accordance with any example described. Plate 1220 can be metal or ceramic.

[0155] In one example, plate 1220 is pitched at angle phi ((D) relative to level, where level refers to an even plane. Mounting plate 1220 at a small angle will allow a substance, such as sand, to stay relatively stationary on plate 1220, while a heated liquid, such as heated bitumen, will flow down the plate toward the edge that is lower.

[0156] Toward the lower edge or at the lower edge, plate 1220 has edge 1222 overlapping a top edge of plate 1230, which is mounted at drop 1224 below plate 1220. Plate 1230 can have a similar angle phi down to edge 1232, overlapping the top edge of plate 1240, which has an angle to allow liquid to flow down to edge 1242. In one example, edge 1222 and edge 1232 can allow heated bitumen to flow down between the plates. In one example, there is a grating at the bottom plate. In one example, the overlapping edges can allow the bitumen to flow down while leaving the sand on the plates.

[0157] In operation, the plates can be heated many hundreds of degrees Celsius (e.g., in a range of 800-1300 C) by the frequency-controlled heating elements. The plates can have dimensions that are dozens of feet in length and many hundreds of feet in width, such a size enabling a truck to directly dump a full load of oil sands onto the heated plate. While the widths would generally be the same, the depths of the plates can vary, such as having a very deep top plate that allows flow down to shallower plates to allow the heated bitumen to flow off. When the oil sands land on the plates, the temperature of the plate will drop by several hundred degrees. The temperature can be managed to still be high enough to cause the bitumen in the sand to have a high enough viscosity to flow down the plates. The heated bitumen can then flow through the grate while leaving the sand on the plates.

[0158] After sufficient time to allow the bitumen to be extracted from the sand, the sand can be moved across the plate, and eventually off the plate. Moving the sand off the plate can make more room to deposit additional oil sands for bitumen extraction. The extraction canoccur without the use of water and through the use of solar heating of the heating elements, which in turn heat the plate. Thus, the bitumen can be extracted with little or no water using renewable energy.

[0159] FIG. 13 is a block diagram of an example of a system to heat a plate via a heat exchanger. System 1300 illustrates a heating system in accordance with an example of system 100 or an example of system 302 or an example of system 902. In one example, system 1300 applies heating elements in accordance with any example herein to provide heat through a heat exchanger to heat a plate for bitumen extraction.

[0160] Solar cell 1310 represents one or more solar cells that generate energy when exposed to light. Control circuit 1320 represents a control circuit in accordance with any example described. Control circuit 1320 is a controller to manage the high-speed switching of energy from solar cell 1310, at a low voltage. The low voltage refers to a voltage in the range of dozens of volts, much lower than a typical grid AC voltage.

[0161] In one example, system 1300 has a one-to-one relationship of controller circuits to heating elements. In one example, a single controller can provide powerto multiple heating elements. Converter 1330[l] represents a first controller circuit to generate signal 1332[1] to control the heating of element 1342[1], Converter 1330[N] represents an Nth controller circuit to generate signal 1332[N] to control the heating of element 1342[N] . N can be any integer.

[0162] Heat exchanger 1340 represents a heat exchange unit to transfer heat from element 1342[1:N], collectively, elements 1342. In one example, heat exchanger 1340 passes heated fluid from elements 1342 to plate 1350. Elements 1342 represent heating elements in accordance with any example herein. Heat exchanger 1340 provides one or more mechanisms to transfer the heat to plate 1350. Plate 1350 can be an example of a plate in accordance with any example herein.

[0163] In one example, heat exchanger 1340 includes a fluid heated by elements 1342 and a radiator and blower for convective heating. In one example, in place of fluid, heat exchanger 1340 can include a salt compound. Heat exchanger 1340 can heat the fluid with elements 1342 to heat plate 1350. In one example, heat exchanger is or includes a radiator system under or through plate 1350.

[0164] Flow diagrams as illustrated herein provide examples of sequences of various process actions. The flow diagrams can indicate operations to be executed by a software or firmware routine, as well as physical operations. A flow diagram can illustrate an example ofthe implementation of states of a finite state machine (FSM), which can be implemented in hardware and / or software. Although shown in a particular sequence or order, unless otherwise specified, the order of the actions can be modified. Thus, the illustrated diagrams should be understood only as examples, and the process can be performed in a different order, and some actions can be performed in parallel. Additionally, one or more actions can be omitted; thus, not all implementations will perform all actions.

[0165] To the extent various operations or functions are described herein, they can be described or defined as software code, instructions, configuration, and / or data. The content can be directly executable ("object" or "executable" form), source code, or difference code ("delta" or "patch" code). The software content of what is described herein can be provided via an article of manufacture with the content stored thereon, or via a method of operating a communication interface to send data via the communication interface. A machine readable storage medium can cause a machine to perform the functions or operations described, and includes any mechanism that stores information in a form accessible by a machine (e.g., computing device, electronic system, etc.), such as recordable / non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.). A communication interface includes any mechanism that interfaces to any of a hardwired, wireless, optical, etc., medium to communicate to another device, such as a memory bus interface, a processor bus interface, an Internet connection, a disk controller, etc. The communication interface can be configured by providing configuration parameters and / or sending signals to prepare the communication interface to provide a data signal describing the software content. The communication interface can be accessed via one or more commands or signals sent to the communication interface.

[0166] Various components described herein can be a means for performing the operations or functions described. Each component described herein includes software, hardware, or a combination of these. The components can be implemented as software modules, hardware modules, special-purpose hardware (e.g., application specific hardware, application specific integrated circuits (ASICs), digital signal processors (DSPs), etc.), embedded controllers, hardwired circuitry, etc.

[0167] Besides what is described herein, various modifications can be made to what is disclosed and implementations of the invention without departing from their scope. Therefore,the illustrations and examples herein should be construed in an illustrative, and not a restrictive sense. The scope of the invention should be measured solely by reference to the claims that follow.

Claims

CLAIMSWhat is claimed is:

1. A system to extract bitumen from oil sands, comprising: a plate to receive oil sands; a heating element; and a converter circuit including a switching circuit to generate a pseudo-DC (direct current) current with high-speed switching of current from a DC source, the converter circuit to drive the heating element with the pseudo-DC current; wherein the heating element is to heat up the plate above 400 C to cause bitumen from the oil sands to flow on the plate.

2. The system of claim 1, wherein the plate is mounted to provide a downward slope to cause the bitumen to flow away from the oil sands.

3. The system of claim 1, wherein the plate includes a grating to allow heated bitumen to pass through.

4. The system of claim 1, wherein the heating element is mounted to the plate to directly heat up the plate.

5. The system of claim 1, wherein the heating element is mounted to a structure attached to the plate, wherein the heating element is to heat up the structure, which will then heat up the plate.

6. The system of claim 5, wherein the structure comprises a reservoir of material surrounding the heating element.

7. The system of claim 6, wherein the material comprises oil or salt.

8. The system of claim 1, wherein heating element is part of a heat exchanger that transfers heated fluid to the plate.

9. The system of claim 1, wherein the heating element comprises a metal coil composed of an alloy of iron, chromium, aluminum, and nickel, the metal coil having a resistance of less than 1.3 ohms.

10. The system of claim 9, wherein the resistance is 1.0 ohms.

11. The system of claim 1, wherein the converter circuit is to generate the pseudo-DC current as a high frequency signal, wherein the converter circuit is to vary a duty cycle of the high frequency signal based on detection of a change in impedance matching between the DC source and the heating element.

12. The system of claim 1, wherein the converter circuit is to generate the pseudo-DC current as a high frequency signal, wherein the high frequency signal comprises a chopped DC current signal.

13. The system of claim 12, wherein the chopped DC current signal comprises a chopped DC signal with a controllable duty cycle.

14. The system of claim 13, wherein the switching circuit comprises a switch circuit driven by a pulse width modulator to create the chopped DC signal with the controllable duty cycle.

15. The system of claim 13, wherein the switching circuit is to change a duty cycle of the high frequency signal in response to detection of a change in impedance of the heating element.

16. The system of claim 15, wherein the switching circuit is to change the duty cycle to maintain a substantially constant ratio between a peak output voltage and an average output current.

17. The system of claim 1, wherein the DC source comprises a PV (photovoltaic) source.

18. The system of claim 17, further comprising: a maximum power point tracking (MPPT) system to detect a maximum power point for energy transfer between the PV source and the heating element; wherein the switching circuit is to power the heating element with power from the PV source.

19. The system of claim 18, wherein the converter circuit is to generate the pseudo-DC current as a high frequency signal, wherein the switching circuit is to vary a duty cycle of the high frequency signal based on detection of a change in impedance matching between the PV source and the heating element.

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