A rotary thermal generator with permanent magnets for heating a liquid

Abstract

The invention relates to a rotary thermal generator with permanent magnets for heating a liquid, comprising: a base (2); a drive; a reservoir (1) to be filled with a liquid; and first and second rotors (5, 6) removably coupled to the drive. The reservoir (1) is mounted on the base (2) and has a first and a second wall that are parallel and opposite to each other. At least the first and second walls of the reservoir (1 ) are formed of electrically conductive, diamagnetic material or electrically conductive, paramagnetic material. The first rotor (5) is adjacent to the first wall of the reservoir (1) and is rotatable relative to the first wall about a first rotational axis, wherein at least two first permanent magnets (9) are arranged in the first rotor (5) on a face adjacent to the first wall of the reservoir (1). The second rotor (6) is adjacent to the second wall of the reservoir (1) and is rotatable relative to the second wall about a second rotational axis, wherein at least two second permanent magnets (10) are arranged in the second rotor (6) on a face adjacent to the second wall of the reservoir (1). The first rotational axis of the first rotor (5) and the second rotational axis of the second rotor (6) are non-identically parallel to each other. The invention further relates to a system and a method for heating a liquid.

Description

[0001] .

[0002] 20 June 2025

[0003] 1

[0004] A rotary thermal generator with permanent magnets for heating a liquid

[0005] Field of technoloqy

[0006] The present invention relates to a rotary thermal generator with permanent magnets for heating water, which operates on the principle of magnetic eddy currents that are generated in a changing magnetic field by the movement of rotating permanent magnets against an electrically conductive material.

[0007] Prior art

[0008] Conventionally, raw materials such as coal, oil, liquefied petroleum gas, etc., are used as the main energy sources for heat and power generation. These sources cause air pollution due to discharge of impurities.

[0009] It is also well known that using electricity for heating is expensive. Currently, heat pumps, direct-fired boilers, electric boilers or electric boilers are used as heat sources to provide hot water.

[0010] Permanent magnets can be used to create magnetic heating systems. These systems generate heat through magnetic field changes in materials with magnetic properties.

[0011] A well-known alternative is thermal devices with permanent magnets. These devices use magnetic eddy currents, which are a phenomenon in electromagnetism that occurs in the presence of a variable magnetic field. These eddy currents are caused by Faraday's law of electromagnetic induction, which describes how an electric current is generated through a conductor when the magnetic field varies in time, and Joule's law, which describes the relationship between thermal energy Q, electric current I, electric voltage V, and time t when an electric current passes through a conductor and the electric energy supplied to the conductor by the current is converted into heat. These currents are caused by induced currents due to motion in a magnetic field.

[0012] Thermal devices with permanent magnets expose an electrical conductor to a changing magnetic field, which creates eddy currents in the conductor, i. e. a circulating flow of electrons. As the electric current flows through the conductor, resistance is created in the conductor and the conductor heats up. Known thermal devices with permanent magnets create eddy currents in a stationary conductor by moving the permanent magnets relative to the stationary conductor. The heat generated by the eddy currents is then used to heat water. However, the problem is that the known permanent magnet thermal devices are inefficient, complex and expensive. In most cases, these permanent magnet devices have undesirable effects, for example, by increasing the temperature around the magnet, which leads to rotational stress on the magnets and thus to a reduction in the performance of the device.

[0013] Induction heating through magnetic eddy currents created by an electromagnetic field is well known and many designers choose this method in order to obtain heat. Most of the proposed solutions do produce heat, but often at the expense of their complexity. In most cases, these permanent magnet devices have undesirable effects, such as an increase in the temperature around the magnet, which leads to rotational stress on the magnets and thus a reduction in the performance of the device.

[0014] A Czech utility model CZ 38122 U1 describes a rotary thermal generator with permanent magnets for heating a liquid, comprising: a base; a drive in the form of a first and a second motor; a reservoir to be filled with a liquid; a first rotor connected to the first motor by a first belt transmission; and a second rotor connected to the second rotor by a second belt transmission. The reservoir is mounted on a base and has first and second walls that are parallel and opposite to each other. At least the first and second walls of the reservoir are formed of an electrically conductive, non-ferromagnetic material. A first rotor is adjacent the first wall of the reservoir and is rotatable relative to the first wall about a first rotational axis, wherein between 4 and 8 first permanent magnets are arranged in the first rotor on a face adjacent the first wall of the reservoir. A second rotor is adjacent the second wall of the reservoir and is rotatable relative to the second wall about a second rotational axis, wherein the second rotor has between 4 and 8 second permanent magnets arranged on a face adjacent the second wall of the reservoir. The first rotational axis of the first rotor and the second rotational axis of the second rotor are coaxial to each other, i. e. identically parallel. In one embodiment, the orientation of the first magnets is coincident (all N), the orientation of the second magnets is coincident (all S), with the first and second magnets facing each other with opposite poles. In another embodiment, the orientation of the first magnets is alternating (NSNS) and the orientation of the second magnets is also alternating (NSNS).

[0015] A US patent application US 2009223948 A1 describes a heater comprising: a first rotor pivotally mounted to a support structure; a first magnet attached to the first rotor; a second rotor pivotally mounted to a support structure, coaxially with the first rotor; and a second magnet attached to the second rotor. Between the first rotor and the second rotor, there is a reservoir which is at least partially made of an electrically conductive, diamagnetic material (e. g. copper). The drive mechanism is configured to rotate the first rotor in a first direction and the second rotor in a second direction opposite to the first direction. In one embodiment, the orientation of the first magnets is coincident (all N) and the orientation of the second magnets is coincident (all S), with the first and second magnets facing opposite poles of each other. In another embodiment, the orientation of the first magnets is alternating (NSNS) and the orientation of the second magnets is also alternating (NSNS).

[0016] The disadvantage of the above heater according to US 2009223948 A1 and the above rotary thermal generator according to CZ 38122 U1 is the coaxial arrangement of the first and second rotor, which creates a suboptimal magnetic field with low efficiency of the whole device. With a coaxial arrangement, the optimal load on the motors cannot be set, the motors and controls overheat during operation in prolonged use and the distance between the rotor and the reservoir must be increased more than twice, further reducing the efficiency of the technology. Already with a COP of approximately 1 , permanent damage to the motors occurs when the rotors are aligned with each other, and the technology cannot be operated continuously. At the maximum load of the motors with an adequate number of permanent magnets to generate the necessary magnetic energy to heat the fluid on the prior art devices, it was not possible to operate the equipment for more than 30 min. in a coaxial rotor arrangement because the motor windings were destroyed and the motors burned (e. g. using a two-pole AC motor, an eight-pole AC motor, a synchronous AC motor with the same negative result).

[0017] A US Patent Application US 2018077759 A1 describes a permanent magnet heat generation device that includes a plurality of rotors fixedly mounted on a common rotating shaft and configured to rotate with the rotating shaft with permanent magnets arranged thereon at predetermined intervals. The heat generating portion is configured to house the rotors therein, thereby forming a predetermined gap between the heat generating portion and the rotors, and thereby adapted to generate heat as the permanent magnets rotate. The motor is configured to serve as a power source for rotating the rotating shaft, and the power transfer means are configured to transfer the power of the rotating motor to the rotating shaft. A Korean patent application KR 20040040435 A describes a device and method for generating heat, wherein the device comprises at least one frame on which one or more permanent magnets are fixedly mounted. A conductive member is arranged adjacent the permanent magnets, a magnetic field is cycled on the conductive member, typically by the permanent magnets, and one or both sides of the conductive member are movable relative to each other. The relative motion of the conductive member and the magnet causes the magnetic field being on the conductive member to change, so that the conductive member begins to heat up and the total thermal energy generated by the conductive member may exceed the total energy supplied to the device to create the changing magnetic field. All frames and conductive members are arranged on a common shaft. The device includes a fluid path adjacent to the conductive member, with the fluid in the fluid path receiving heat from the conductive member. The apparatus further includes a mounting member for mounting the conductive member, a drive mechanism for moving the conductive member, and a fluid drive for driving the fluid in the fluid path. The method includes the steps of heating one or both of the conductive element and the permanent magnet in the vicinity of the conductive element and passing the fluid through the fluid path in the vicinity of the conductive element such that the fluid absorbs heat from the conductive element.

[0018] A European patent application EP 2645548 A2 describes a synchronous electrical machine comprising a rotor, a plurality of permanent magnets and a thermally conductive compound, wherein the rotor has a substantially cylindrical core with axially extending grooves, the plurality of permanent magnets includes a set of defining circumferentially alternating poles arranged in each of the grooves, and the thermally conductive compound is adjacent to the permanent magnets and the core for transferring heat from the permanent magnets to the core and has a thermal conductivity greater than 0.3 W / (m.K).

[0019] Thus, in the state of the art, a need arises, and the object of the invention is to provide a rotary thermal generator with permanent magnets for heating a liquid that is efficient, simple in design, powerful and low in operating cost.

[0020] Summary of the invention

[0021] Said objective is achieved in a first aspect of the present invention by a rotary thermal generator with permanent magnets for heating a liquid, comprising: a base; a drive; a reservoir to be filled with a liquid; and a first and a second rotor removably coupled to the drive. The liquid in the context of the present invention may be water, oil, antifreeze or ferrofluid.

[0022] The reservoir is mounted on the base and has a first and a second wall that are parallel and opposite to each other. At least the first and second walls of the reservoir are formed of an electrically conductive, diamagnetic material or electrically conductive, paramagnetic material.

[0023] The first rotor is adjacent the first wall of the reservoir and is rotatable relative to the first wall about a first rotational axis. At least two first permanent magnets are arranged in the first rotor on a face adjacent to the first wall of the reservoir.

[0024] The second rotor is adjacent to the second wall of the reservoir and is rotatable relative to the second wall about a second rotational axis. At least two second permanent magnets are arranged in the second rotor on a face adjacent the second wall of the reservoir.

[0025] The rotational motion of the first and second rotors relative to the stationary reservoir induces eddy currents in the electrically conductive, diamagnetic material or electrically conductive, paramagnetic material of the reservoir. The eddy currents generate Joule heat and cause heating of the walls of the reservoir, and consequently heating of the liquid in the reservoir. The term "adjacent to a wall of the reservoir " means the position of the first or second rotor near the reservoir so that the first or second wall of the reservoir is within the magnetic field of the rotating permanent magnets.

[0026] The underlying idea of the rotary thermal generator according to the present invention is that the first rotational axis of the first rotor and the second rotational axis of the second rotor are non-identically parallel to each other. In other words, the face of the second rotor is always oriented off-axis with respect to the face of the first rotor and the rotors are always vertically and horizontally off-set with respect to each other.

[0027] In a preferred embodiment, the first rotational axis of the first rotor passes through a centre of the first rotor and the first permanent magnets are arranged at the same distance from the centre of the first rotor. In this embodiment, by analogy, the second rotational axis of the second rotor passes through a centre of the second rotor and the second permanent magnets are arranged at the same distance from the centre of the second rotor. The first and second rotors may thus have a shape of a disc. All the first permanent magnets are arranged so that they face the first wall of the reservoir with identical magnetic poles (e. g. NNNN). The second permanent magnets are arranged so that each two adjacent permanent magnets face the second wall of the reservoir with opposing magnetic poles (i. e. the magnetic poles are alternating, e. g. NSNS). Such an asymmetric arrangement of the magnetic poles produces larger changes in the magnetic field intensity compared to all magnetic poles arranged identically and all magnetic poles arranged in alternation, which increases the efficiency of the entire device. Alternatively, the number and arrangement of permanent magnets between the first and second rotors may vary, each rotor may contain a different number of permanent magnets and may not have the above arrangement of magnetic poles.

[0028] In a preferred embodiment, the first rotational axis of the first rotor (with the first permanent magnets arranged with identical magnetic poles, see above) is offset from the second rotational axis of the second rotor (with the second permanent magnets arranged with alternating magnetic poles, see above) in a horizontal plane perpendicular to the direction of gravity by at least a full diameter of the first permanent magnet and simultaneously in a vertical plane perpendicular to the above horizontal plane by at least half a diameter of the first permanent magnet. In this embodiment, the permanent magnet is cylindrical in shape. The direction of rotation of the aligned first rotor is to the right, i. e. opposite to the standard rotation of conventional motors.

[0029] In a preferred embodiment, the drive is a common motor removably coupled to the first and second rotors. In another preferred embodiment, the drive is a first motor removably coupled to the first rotor and a second motor removably coupled to the second rotor. The first rotor may be removably coupled to the drive by a first coupling and the second rotor may be removably coupled to the drive by a second coupling. The couplings may be, for example, elastomeric shaft couplings. The rotors may also be connected to the drive (with a common motor or with the first or second motor) by a belt transmission.

[0030] In a preferred embodiment, the drive is mounted on the base, or it can be mounted separately.

[0031] Although it is sufficient that at least the first and second walls of the reservoir (adjacent the first and second rotor with permanent magnets, respectively) are formed of an electrically conductive, diamagnetic material or electrically conductive, paramagnetic material, in a preferred embodiment the entire reservoir is formed of an electrically conductive, diamagnetic material, such as copper or a copper alloy. Copper and copper alloys are stable materials with high conductivity and temperature resistance. Copper metal, despite its electron configuration and unpaired electron in the 4s orbital, exhibits diamagnetic properties, not paramagnetic, and is therefore considered a diamagnetic material. In another preferred embodiment, the entire reservoir is formed from an electrically conductive, paramagnetic material, such as aluminium. Thus, the reservoir is made of a diamagnetic or paramagnetic material having a high current conductivity and low electrical resistance, which allows it to be heated. Since the reservoir is used directly as a heat exchanger, its thermal efficiency is considerably high. No toxic gases are emitted during heat generation, making the rotary thermal generator environmentally friendly with zero emissions.

[0032] In a preferred embodiment, the reservoir is in the shape of a rectangular cuboid, a cube, a polyhedron with parallel bases (e. g. hexagon, octagon) or a cylinder. The bases of the reservoir are parallel to the faces of the first or second rotor, respectively.

[0033] In a preferred embodiment, there are 4 to 24 first permanent magnets arranged in the first rotor on a face adjacent the first wall of the reservoir and 4 to 24 second permanent magnets arranged in the second rotor on a face adjacent the second wall of the reservoir. Preferably, the number of permanent magnets is even, and two permanent magnets are always arranged symmetrically with respect to the centre of the rotor face. Preferably, the number of first permanent magnets is 24 with a consonant magnetic pole orientation (e. g. NNNNNN NNNNNN NNNNNN NNNNNN) and the number of second permanent magnets is 24 with alternating magnetic pole orientations (e. g. NSNSNS NSNSNS NSNSNS NSNSNS).

[0034] In a preferred embodiment, the permanent magnet is made of NdFeB, SmCo or AINiCo alloy. Neodymium magnets (NdFeB) are universally applicable. SmCo or AINiCo magnets can be used at higher operating temperatures above 80 °C because they have a high magnetic induction, are thermally stable and resistant to corrosion.

[0035] In a preferred embodiment, the permanent magnet is cylindrical in shape with a diameter of 18 to 22 mm (e. g. 20 mm) and a height of 2 to 4 mm (e. g. 3 mm) and has a magnet breakaway force of 4 to 5 kg (e. g. 4.3 kg). The total sum of the breakaway force of the permanent magnets is greater than 100 kg per rotor. Conversely, when the permanent magnets have a breakaway force greater than 250 kg per rotor, a reduction in the overall system efficiency has been observed. The total sum of the permanent magnet breakaway force is less than 250 kg per rotor.

[0036] In a preferred embodiment, the first and second rotors are made of a paramagnetic material, such as duralumin, which increases the efficiency of the entire device.

[0037] In a preferred embodiment, a DC motor with an inverter or an AC motor powered by one or more batteries that can be charged by a renewable energy source, such as solar panels, is used to drive the motor(s), eliminating the need for an external power supply.

[0038] In a preferred embodiment, the liquid is a mixture of oil and magnetic nanoparticles (so- called ferrofluid), e. g. a mixture of oil and magnetic carbon nanoparticles in a weight ratio of 115:1 to 145:1 . This creates a positive electrical charge for each nanoparticle and each nanoparticle represents a miniature permanent magnet due to its magnetic moment. There is also an increase in viscosity with increasing magnetic field strength. The magnetic fluid moves to where the magnetic induction is strongest, and as the rotational frequency increases, the magnetic fluid absorbs energy and heats up. When the above fluid is used, the properties of a supermagnetic are retained, but without the effects of magnetic field lines on the surface. The fluid becomes paramagnetic only when the rotating thermal generator is started and operated, and it becomes diamagnetic again when the generator is idle. The above fluid can further heat, for example, water via a heat exchanger.

[0039] The oil can be a silicone oil, hydraulic oil, gear oil, transformer oil or any edible oil such as sunflower or rapeseed oil. Edible oils are naturally environmentally friendly as they are biodegradable. It is also advantageous to use rapeseed oil methyl ester (FAME, fatty acid methyl ester). All of these oils or FAMEs have similar viscosities and differ only slightly in the resulting COP.

[0040] The magnetic nanoparticles may be carbon nanoparticles, optionally with an admixture of iron (III) oxide nanoparticles (Fe2Os) and / or iron (ll)-(lll) oxide (FesO4), preferably up to 5 wt. %.

[0041] The magnetic nanoparticles may be contained in a mixture for the preparation of a ferrofluid, wherein said mixture comprises 75 to 85 wt. % magnetic carbon nanoparticles, 10 to 15 wt. % S1O2, 3 to 5 wt. % polypropylene wax, 2 to 4 wt. % Fe2Os, and 0,5 to 2 wt. % polymethyl methacrylate.

[0042] In a preferred embodiment, the liquid is a mixture of 95.0 to 99.5 wt. % oil (see a list of suitable oils above) and 0.5 to 5.0 wt. % magnetic carbon nanoparticles. In a preferred embodiment, the liquid is a mixture of 95.0 to 99.5 wt. % oil (see list of suitable oils above) and 0.5 to 5.0 wt. % of the above mixture for the preparation of a ferrofluid.

[0043] At a percentage of the above mixture of less than 0.5 wt. %, the liquid does not become ferromagnetic throughout its volume and the COP does not change compared to the oil without the above mixture. With a percentage of the above mixture greater than 2.0 wt. %, the COP is no longer changed compared to the 0,5 to 2,0 wt. % content of the above mixture.

[0044] In a preferred embodiment, the liquid is a mixture of the magnetic nanoparticles described above and any liquid selected from water, coolant or alcohol (e. g. ethanol).

[0045] Said objective is achieved in a second aspect of the present invention by a system for heating a liquid, comprising the above-mentioned rotary thermal generator. The reservoir is bi-directionally fluidly connected to an accumulation tank for supplying the heated liquid further to a heating system or to an ORC unit for generating electrical power (ORC = organic Rankine cycle). The reservoir of the rotary thermal generator can be connected directly to the inlet of the accumulation tank, the outlet of which is connected back to the reservoir via an expansion tank and a pump.

[0046] Said objective is achieved in the third aspect of the present invention by a method for heating a liquid by the above-mentioned rotary thermal generator, such that the liquid in the reservoir is heated by heat generated by eddy currents present in at least the first and second walls of the reservoir from an electrically conductive, diamagnetic material or electrically conductive, paramagnetic material as a result of the magnetic field of the rotating first and second rotors with permanent magnets.

[0047] The underlying idea of the method for heating the liquid according to the present invention is that the first and second rotors rotate in the same direction, preferably at a speed of 2300 to 3000 rpm, more preferably at a speed of 2600 to 3000 rpm (depending on the application). In other words, the direction of rotation of the first rotor (and therefore the first motor) may be to the right (i. e. opposite to the standard leftward rotation of, for example, AC induction motors) and the direction of rotation of the second rotor (and therefore the second motor) may be to the left, so that both rotors rotate in the same direction. Rotating the rotors in the same direction results in reduced noise, whistling and vibration of the entire device while maintaining magnetic properties and efficiency. The rotational speed of the first and second rotors may be varied with the intention of optimizing performance in a particular embodiment.

[0048] In a preferred embodiment, the liquid may be water, oil, antifreeze or ferrofluid, and preferably any mixture of oil and magnetic nanoparticles specified above.

[0049] Brief description of drawings

[0050] Figure 1 shows a front view of a rotary thermal generator configuration with permanent magnets for heating a liquid.

[0051] Figure 2 shows a top view of a rotary thermal generator.

[0052] Figure 3 shows an axonometric view of a rotary thermal generator.

[0053] Figure 4 shows the polarization of the magnets of the first rotor.

[0054] Figure 5 shows the polarization of the magnets of the second rotor.

[0055] Figure 6 shows an exemplary integration of the rotary thermal generator into a heating system.

[0056] Figure 7 shows an exemplary integration of the rotary thermal generator into an ORC unit.

[0057] Figure 8 shows the results of using a rotary generator in water heating.

[0058] Example 1

[0059] Figures 1 , 2 and 3 show a rotary thermal generator with permanent magnets for heating a liquid, comprising: a base 2; a drive in the form of a first motor 3 and a second motor 4; a reservoir 1 to be filled with a liquid (e. g. with water, oil, antifreeze or ferrofluid, preferably with a mixture of oil and magnetic carbon nanoparticles); a first rotor 5 removably coupled to the first motor 3 by a shaft of the first rotor 5 and a first coupling 7 (e. g. an elastomeric shaft coupling); and a second rotor 6 removably coupled to the second motor 4 by a shaft of the second rotor 6 and a second coupling 8 (e. g. an elastomeric shaft coupling). The shafts of the first and second rotors 5, 6, respectively, are attached to the rotor faces by flanges in a direction perpendicular to the centre of the rotor face.

[0060] The reservoir 1 is mounted on the base 2 and has a first and a second wall (e. g. having a thickness of 1 to 6 mm, e. g. 2, 3 or 4 mm) that are parallel and opposite to each other (e. g. the bases of a rectangular cuboid or a cylinder). At least the first and second walls of the reservoir 1 , preferably the entire reservoir 1 , are formed of an electrically conductive, diamagnetic material (e. g. copper or copper alloy). Alternatively, at least the first and second walls of the reservoir 1 , preferably the entire reservoir 1 , are formed of an electrically conductive, paramagnetic material (e. g. aluminium).

[0061] The first rotor 5 (e. g. disc-shaped, made of duralumin) is adjacent the first wall of the reservoir 1 and is rotatable relative to the first wall about a first rotational axis. In the first rotor 5, there are 24 first permanent magnets 9 arranged on a face adjacent the first wall of the reservoir 1 (Figure 4). The first permanent magnets 9 may be housed in holes formed in the face of the first rotor 5, where they may be sealed with an adhesive together with an aluminium seal. The first rotational axis of the first rotor 5 passes through the centre of the first rotor 5, and the first permanent magnets 9 are arranged at the same distance from the centre of the first rotor 5 (i. e. they describe a circle around the centre of the first rotor 5). All the first permanent magnets 9 are arranged so that they face the first wall of the reservoir 1 with identical magnetic poles (e. g. NNNN etc.) and always a pair of two first permanent magnets 9 is arranged symmetrically with respect to the centre of the face of the first rotor 5. The breakaway force of the first permanent magnets 9 is greater than 100 kg.

[0062] A second rotor 6 (e. g. disc-shaped, made of duralumin) is adjacent the second wall of the reservoir 1 and is rotatable relative to the second wall about a second rotational axis. In the second rotor 6, there are 24 second permanent magnets 10 arranged on a face adjacent the second wall of the reservoir 1 (Figure 5). The second permanent magnets 10 may be housed in holes formed in the face of the second rotor 6, where they may be sealed with an adhesive together with an aluminium seal. The second rotational axis of the second rotor 6 passes through the centre of the second rotor 6, and the second permanent magnets 10 are arranged at the same distance from the centre of the second rotor 6 (i. e. they describe a circle around the centre of the second rotor 6). The second permanent magnets 10 are arranged such that each two adjacent permanent magnets 10 face the second wall of the reservoir 1 with opposing magnetic poles (i. e. the magnetic poles alternate, e. g. NSNS, etc.) and always a pair of two second permanent magnets 10 is arranged symmetrically with respect to the centre of the face of the second rotor 6. The breakaway force of the second permanent magnets 10 is greater than 100 kg.

[0063] The first rotational axis of the first rotor 5 and the second rotational axis of the second rotor 6 are non-identically parallel to each other, i. e. they lie in the same plane, do not intersect and are equidistant (Figures 1 and 2). The first rotational axis of the first rotor 5 is offset from the second rotational axis of the second rotor 6 in the horizontal plane, which is perpendicular to the direction of the gravitational force, by at least an entire diameter of the first permanent magnet 9, and simultaneously in the vertical plane, which is perpendicular to the aforementioned horizontal plane, by at least half of the diameter of the first permanent magnet 9. The first motor 3 and the second motor 4 are mounted on the base 2 by means of holders 11 , 12. The holders 11 , 12 allow the vertical and horizontal displacement of the motors 3, 4 and therefore of the rotors 5, 6, thereby allowing the above condition of the first and second rotational axes to be set.

[0064] The liquid in the reservoir 1 is heated by heat generated by eddy currents present in at least the first and second walls of the reservoir 1 made of electrically conductive, diamagnetic material or electrically conductive, paramagnetic material as a result of the magnetic field of the rotating first and second rotors 5, 6 with permanent magnets 9, 10. The first and second rotors 5, 6 rotate in the same direction at a speed of 2300 to 3000 rpm (first rotor 5 to the right and second rotor 6 to the left), for example at a speed of more than 2600 rpm. The power of the first and second motors 3, 4 (e. g. a DC motor without commutation) is in the range of 250 to 400 W, e. g. 280, 290 or 300 W.

[0065] Example 2

[0066] In accordance with Example 1 , the drive is a common motor removably coupled by a first belt drive to the first rotor 5 and a second belt drive to the second rotor 6 (not shown in the drawings). The first rotor 5 is connected to a shaft by a flange, and there is a driven pulley arranged on the shaft, which driven pulley is driven by a driving pulley by means of a belt of a belt transmission, which driving pulley is arranged on a first shaft of the common motor. The second rotor 6 is connected to a shaft by a flange, and there is a driven pulley arranged on the shaft, which driven pulley is driven by a driving pulley by means of a belt of a belt transmission, which driving pulley is arranged on a second shaft of the common motor. The shafts of the first or second rotor 5, 6 may be mounted in bearings which are arranged in bushings mounted on the holders 11 , 12, or directly on the base 2.

[0067] The first and second shafts of the common motor may be coaxial and point in opposite directions of the common motor if the common motor is arranged below the reservoir 1 . The first and second shafts of the common motor may be coaxial and point in the same direction if the common motor is arranged adjacent to the reservoir 1 .

[0068] Example 3

[0069] In accordance with Example 1 , the drive is a first motor 3 removably coupled by a first belt drive to a first rotor 5, and a second motor 4 removably coupled by a second belt drive to a second rotor 6 (not shown in the drawings). The first rotor 5 is connected to a shaft by a flange, and there is a driven pulley arranged on this shaft, which driven pulley is driven by a driving pulley by means of a belt of the belt transmission, which driving pulley is arranged on a shaft of the first motor 3. The second rotor 6 is connected to a shaft by a flange, and there is a driven pulley arranged on this shaft, which driven pulley is driven by a driving pulley by means of a belt of the belt transmission, which driving pulley is arranged on a shaft of the second motor 4.

[0070] The shafts of the first or second rotor 5, 6 may be mounted in bearings which are arranged in bushings mounted on the holders 11 , 12, or directly on the base 2.

[0071] Example 4

[0072] In accordance with the previous examples, the first and second permanent magnets 9, 10 are made of NdFeB, SmCo or AINiCo alloy.

[0073] Example 5

[0074] In accordance with the previous examples, the first and second permanent magnets 9, 10 are cylindrical in shape with a diameter of 20 mm and a height of 3 mm and have a magnet breakaway force of 4.3 kg.

[0075] Example 6

[0076] Figure 6 illustrates a system for heating a liquid, comprising the above rotary thermal generator according to the preceding examples. The reservoir 1 is bi-directionally fluidly connected to an accumulation tank 13 for supplying the heated liquid further to a heating system 21. The reservoir 1 is connected directly to an inlet of the accumulation tank 13, an outlet of which is connected back to the reservoir 1 via an expansion tank 15 and a pump 18. A pump 18 is also included between the heating system 21 and the accumulation tank 13.

[0077] The liquid from the accumulation tank 13 is heated in the reservoir 1 . The heated liquid is drained from the reservoir 1 and is returned to the accumulation tank 13 through the outlet pipe of the heating system 21. When the liquid from the accumulation tank 13 is used for the operation of the heating system 21 for the supply of hot water, the accumulation tank 13 is replenished with heated water from the reservoir 1 to the required liquid temperature for the operation of the heating system 21 .

[0078] The water from the reservoir 1 is mixed with the liquid in the accumulation tank 13, which is then heated by the rotary thermal generator. The water is drained from the accumulation tank 13, heated and returned to the accumulation tank 13, thereby maintaining the accumulation tank 13 within the desired temperature range.

[0079] Example 7

[0080] Figure 7 shows a system for heating a liquid comprising the above rotary thermal generator according to the preceding examples. The reservoir 1 is bi-directionally fluidly connected to an accumulation tank 13 for supplying the heated liquid further to an ORC unit 14 for generating electrical power. The reservoir 1 is connected directly to an inlet of the accumulation tank 13, an outlet of which is connected back to the reservoir 1 via an expansion tank 15 and a pump 18. Between the ORC unit 14 and the accumulation tank 13, there are also a pump 18, a thermostat 20 and a three-way valve 16 to allow the liquid to be returned to the accumulation tank 13 without reaching the ORC unit 14 (so-called hot loop). From the ORC unit, a so-called cold loop then leads to a cooler 17 (e. g. a dry cooler), and then back via a pump 18. The ORC unit is controlled by the control unit 19 to generate electrical power.

[0081] The liquid from the accumulation tank 13 is heated in the reservoir 1 . The heated liquid is drained from the reservoir 1 and is returned to the accumulation tank 13 through the hot loop outlet pipe. When the liquid from the accumulation tank 13 is used for operation of the ORC unit 14 to generate electrical power, the accumulation tank 13 is replenished with heated water from the reservoir 1 to the desired liquid temperature required for operation of the ORC unit 14. The water from the reservoir 1 is mixed with the liquid in the accumulation tank 13, which is then heated by the rotary thermal generator. By using a thermostat 20 to control the frequency and rate at which water is drained from the accumulation tank 13, heated and returned to the accumulation tank 13, the temperature of the water in the accumulation tank 13 can be maintained within a desired temperature range, which can be controlled by the control unit 19.

[0082] Example 8

[0083] Figure 8 is a graph showing a comparison between the thermal efficiency of a rotary thermal generator according to the present invention and the thermal efficiency of a typical electric heater. As shown in Fig. 8, water at a temperature of 50.3 °C was obtained by heating water at a temperature of 25 °C using a power input of 550 W (220 V x 2.5 amp.) for 1 h, thereby achieving a temperature increase of 25.3 °C.

[0084] In the case of the rotary thermal generator according to the present invention, the thermal efficiency was 1 .012 kcal / h and was thus 2.14 times higher than that of a typical electric heater in terms of coefficient of performance (COP). This shows that the efficiency is at least twice as high as that of an electric heater.

[0085] Example 9

[0086] Table 1 below compares the measured water heating time and power consumption of a prototype rotary thermal generator according to the present invention, coupled to a 1000 litre reservoir, and a 5 kW electric heater. It can be seen from Table 1 that in the case of the rotary thermal generator according to the present invention, the water heating time is approximately 2.8 times shorter, and the electricity consumption is approximately 4 times lower than that of the measured electric heater.

[0087]

[0088] Table 1 : Comparison of a rotary thermal generator and an electric heater for heating water from 10 °C to 60 °C.

[0089] Example 10

[0090] The liquid for filling the reservoir 1 is a mixture of 99.0 wt. % rapeseed oil (5 I, 4600 g) and 1.0 wt. % mixture for preparing a ferrofluid (40 g). This mixture contains 80 wt. % magnetic carbon nanoparticles, 13 wt. % SiC>2, 4 wt. % polypropylene wax, 3 wt. % Fe2Os, and 1 wt. % polymethyl methacrylate.

[0091] Example 11

[0092] The liquid for filling the reservoir 1 is a mixture of 98.5 wt.% rapeseed oil (5 I, 4600 g) and 1 .5 wt.% mixture for preparing a ferrofluid (70 g). This mixture contains 80 wt. % magnetic carbon nanoparticles, 13 wt. % SiC>2, 4 wt. % polypropylene wax, 3 wt. % Fe2Os, and 1 wt. % polymethyl methacrylate.

[0093] Industrial applicability

[0094] The rotary thermal generator described above can be used as a stand-alone system for heating and / or for maintaining hot water in a reservoir. The water is piped from the reservoir to the accumulation tank. Alternatively, the accumulation tank is positioned above the reservoir such that the liquid passes from the accumulation tank to the reservoir via gravity feed. List of reference siqns

[0095] 1 reservoir

[0096] 2 base

[0097] 3 first motor

[0098] 4 second motor

[0099] 5 first rotor

[0100] 6 second rotor

[0101] 7 first coupling

[0102] 8 second coupling

[0103] 9 first permanent magnet

[0104] 10 second permanent magnet

[0105] 11 holder of the first motor 3

[0106] 12 holder of the second motor 4

[0107] 13 accumulation tank

[0108] 14 ORC unit

[0109] 15 expansion tank

[0110] 16 three-way valve

[0111] 17 cooler

[0112] 18 pump

[0113] 19 control unit

[0114] 20 thermostat

[0115] 21 heating system

Claims

CLAIMS1 . A rotary thermal generator with permanent magnets for heating a liquid, comprising: a. a base (2); b. a drive; c. a reservoir (1 ) to be filled with a liquid, mounted on the base (2), wherein the reservoir (1 ) has a first and a second wall that are parallel and opposite to each other, wherein at least the first and second walls of the reservoir (1 ) are formed of an electrically conductive, diamagnetic material or electrically conductive, paramagnetic material; d. a first rotor (5) removably coupled to the drive, wherein the first rotor (5) is adjacent to the first wall of the reservoir (1 ) and is rotatable relative to the first wall about a first rotational axis, and wherein at least two first permanent magnets (9) are arranged in the first rotor (5) on a face adjacent to the first wall of the reservoir (1); and e. a second rotor (6) removably coupled to the drive, wherein the second rotor (6) is adjacent to the second wall of the reservoir (1 ) and is rotatable relative to the second wall about a second rotational axis, and wherein at least two second permanent magnets (10) are arranged in the second rotor (6) on a face adjacent to the second wall of the reservoir (1 ); characterised in that the first rotational axis of the first rotor (5) and the second rotational axis of the second rotor (6) are non-identically parallel to each other.

2. The rotary thermal generator according to claim 1 , characterised in that the first rotational axis of the first rotor (5) passes through a centre of the first rotor (5) and the first permanent magnets (9) are arranged at the same distance from the centre of the first rotor (5), wherein the second rotational axis of the second rotor (6) passes through a centre of the second rotor (6) and the second permanent magnets (10) are arranged at the same distance from the centre of the second rotor (6), wherein all the first permanent magnets (9) are arranged so that they face the first wall of the reservoir (1 ) with identical magnetic poles, and wherein the second permanent magnets (10) are arranged so that each two adjacent permanent magnets (10) face the second wall of the reservoir (1 ) with opposing magnetic poles.

3. The rotary thermal generator according to claim 1 or 2, characterised in that the drive is a common motor removably coupled to the first and second rotors (5, 6), or in that the drive is a first motor (3) removably coupled to the first rotor (5) and a second motor (4) removably coupled to the second rotor (6).

4. The rotary thermal generator according to claim 3, characterised in that the first rotor (5) is removably coupled to the drive by means of a first coupling (7) and the second rotor is removably coupled to the drive by means of a second coupling (8).

5. The rotary thermal generator according to any one of claims 1 to 4, characterised in that the entire reservoir (1 ) is formed of an electrically conductive, diamagnetic material or electrically conductive, paramagnetic material.

6. The rotary thermal generator according to any one of claims 1 to 5, characterised in that the electrically conductive, diamagnetic material is copper or a copper alloy.

7. The rotary thermal generator according to any one of claims 1 to 6, characterised in that the reservoir (1 ) is in the shape of a rectangular cuboid, a cube, a polyhedron with parallel bases or a cylinder.

8. The rotary thermal generator according to any one of claims 1 to 7, characterised in that in the first rotor (5), there are between 4 and 24 first permanent magnets (9) arranged on the face adjacent to the first wall of the reservoir (1 ) and in the second rotor (6), there are between 4 and 24 second permanent magnets (10) arranged on the face adjacent to the second wall of the reservoir (1).

9. The rotary thermal generator according to any one of claims 1 to 8, characterised in that the permanent magnet (9, 10) is made of NdFeB, SmCo or AINiCo alloy.

10. The rotary thermal generator according to any one of claims 1 to 9, characterised in that the permanent magnet (9, 10) is cylindrical in shape with a diameter of 18 to 22 mm and a height of 2 to 4 mm and has a magnet breakaway force of 4 to 5 kg.

11. The rotary thermal generator according to any one of claims 1 to 10, characterised in that the total sum of the breakaway force of the permanent magnets is greater than 100 kg per rotor (5, 6).

12. A system for heating a liquid, comprising the rotary thermal generator according to any one of claims 1 to 11 , characterised in that the reservoir (1) is bi-directionallyfluidly connected to an accumulation tank (13) for supplying the heated liquid further to a heating system or to an ORC unit for generating electrical power.

13. A method for heating a liquid by the rotary thermal generator according to any one of claims 1 to 11 or the system according to claim 12, characterised in that the liquid in the reservoir (1) is heated by heat generated by eddy currents present in at least the first and second walls of the reservoir (1) from an electrically conductive, diamagnetic material or electrically conductive, paramagnetic material as a result of the magnetic field of the rotating first and second rotors (5, 6) with permanent magnets (9, 10), wherein the first and second rotors (5, 6) rotate in the same direction.

14. The method of claim 14, characterised in that the first and second rotors (5, 6) rotate at a speed of 2300 to 3000 rpm.

15. The method according to claim 14 or 15, characterised in that the liquid is a mixture of 95.0 to 99.5 wt. % oil and 0.5 to 5.0 wt. % magnetic carbon nanoparticles.

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