CONVERSION DEVICE OF THERMAL ENERGY INTO ELECTRICAL ENERGY

[0001] The object of the present invention is a conversion device of thermic energy into electrical energy, in particular for the steel industry.

[0002] Recently, heat recovery solutions, in particular the excess heat produced by production facilities and processes, have known considerable interest.

[0003] There are in fact many industries that produce large heat resources that are not exploited: iron and steel industries, cement factories, foundries, refineries, thermal treatments, glass factories, chemical industries, thermoelectric and power generation plants. All of these industries, and in particular the steel industries, daily generate huge amounts of heat that must be dissipated by proper cooling system, or that are naturally dispersed in the environment.

[0004] This heat is in fact a valuable and extensive source of thermic energy. Therefore, the solutions for heat recovery and utilization of waste heat are increasingly interesting .

[0005] The heat produced by production facilities and processes can in fact be recovered in the same moment in which it is dissipated, and can be used for example for the production of electrical energy.

[0006] The object of the present invention is to provide a conversion device of thermic energy into electrical energy .

[0007] Such an object is achieved by a conversion device made according to claim 1, and by a conversion assembly made according to claims 12, 14 and 15. The dependent claims describe preferred or advantageous embodiments of the device.

[0008] The features and advantages of the device according to the present invention will appear more clearly from the following description, made by way of an indicative and non-limiting example with reference to the annexed figures, wherein:

[0009] - figure 1 shows an axonometric view of a conversion device of thermic energy into electrical energy according to the present invention;

[0010] - figure 2 shows an axonometric view of a conversion device of thermic energy into electrical energy according to the present invention, in one embodiment;

[001 1 ] - figure 3 shows an axonometric view of a conversion device of thermic energy into electrical energy according to the present invention, in a further embodiment;

[0012] - figure 4 shows an axonometric view of a plurality of conversion devices of thermic energy into electrical energy, according to the configuration of figure 3, applied to a duct supplied for example with air;

[0013] - figure 5 shows an axonometric view of a conversion device of thermic energy into electrical energy, according to the configuration of figure 2, applied to a cooling panel supplied for example with water;

[0014] - figure 6 shows an axonometric view of a plurality of cooling panels provided with conversion devices, according to the configuration of figure 5, in a modular exemplary embodiment;

[0015] - figure 7 shows an axonometric view of a conversion device of thermic energy into electrical energy, according to the configuration of figure 2, to which a heat sink is applied.

[0016] With reference to the attached figures, reference numeral 10 generally indicates a conversion device of thermic energy into electrical energy, supplied with heat generated by the processing of industrial installations, in particular for the steel industry.

[0017] The conversion device 10 uses the operating principle of the Peltier cell.

[0018] In particular, the conversion device 10 comprises a plurality of elementary pairs 1,2,3, n consisting of two active elements (or prisms or cylinders or ingots) in semi-conductor material. [0019] In one embodiment, the elementary pair comprises two active elements in the form of cylinders having a diameter of about 25mm and a height of about 30mm. The base semi-conductor material has a doping of the P type in one of the two elements (called element P) and doping of the N type in the other element (called element N) .

[0020] In each elementary pair, the two active elements P and N are connected together at one end, and at the opposite end they are connected with the respective element N or P of the adjacent elementary pair.

[0021 ] The elements P, N are connected by junctions 11. Junction 11 is of metal, preferably copper.

[0022] In one embodiment, shown in figure 1, junctions 11 are copper plates or strips.

[0023] The conversion device 10 comprises a plurality of elementary pairs 1,2,3, n (or pairs P, N) joined by junctions 11 to form a circuit in which, in the presence of a temperature difference ΔΤ between the ends of the active elements P and N, in the circuit of the elementary pairs 1,2,3, n a direct current proportional to the thermal gradient applied flows.

[0024] The first elementary pair of the circuit (indicated with reference numeral 1 in figure 1) is provided with a junction lip, adapted to be connected to an electrical connection (for example to a positive pole) and the last elementary pair of the circuit (indicated with letter n in figure 1) is provided with a junction lln, adapted to be connected to an electrical connection (for example to a negative pole) .

[0025] The conversion device 10 comprises a lower plate 14 and an upper plate 16, adapted to enclose the circuit of the elementary pairs 1,2,3, n (or pairs P, N) .

[0026] Plates 14,16 are made of metal, preferably steel, even more preferably stainless steel or aluminium.

[0027] In use, one of the two plates, for example the lower plate 14, is heated, while the other one, for example the upper plate 16, is cooled.

[0028] The plates can be heated/cooled by radiation or conduction or convection. For example, a plate can be heated with oil or air, and the other cooled for example with air or liquid. Moreover, the plates may be provided with heat sinks 80 to increase the useful surface for the heat exchange.

[0029] In use, by heating one side of the conversion device 10 and cooling the other, in the circuit of the elementary pairs 1,2,3, n (or pairs P-N) , suitably connected via junctions lip, lln to an electric circuit, a current will flow which is proportional to the thermal gradient present between the two plates 14, 16.

[0030] The appearance of a difference in the electrical voltage at the ends of the circuit is then due to the temperature difference ΔΤ between the two plates 14, 16, and depends on the type of material used for elements P and N .

[003 1 ] In a preferred embodiment, element P comprises Silver, Antimony and Tellurium, and element N comprises Germanium and Tellurium. A conversion device 10 with elements P, N thus made is particularly efficient and high performance.

[0032] Preferably, the stoichiometric composition is:

[0033] Element P: (Ag Sb Te) 0.1-0.3

[0034] Element N: (Ge Te) 0.7-0.9

[0035] A pair of elements P and N with such a stoichiometric composition allows developing a power of about 20W, for a temperature difference ΔΤ of about 300°C between the two plates (for example, when the lower plate 14 is heated to about 300°C and the upper plate 16 is cooled to about 20°C) .

[0036] Preferably, element P includes Silver, Antimony and Tellurium or Lead, Tin and Tellurium.

[0037] Preferably, element N includes Germanium and Tellurium, or Lead and Tellurium, or Tin and Tellurium, or Silicon and Germanium.

[0038] In one embodiment, the conversion device 10 comprises a circuit of five hundred elementary pairs (or pairs P-N ) .

[0039] In one embodiment, a conversion device 10 comprising :

[0040] - five hundred elementary pairs P-N

[0041 ] - with P: (Ag Sb Te)0.1-0.3 and : (Ge Te)0.9-0.7

[0042] allows developing a power of approximately 10,000 , for a temperature difference ΔΤ of about 300 °C. A conversion device 10 thus formed ensures a high efficiency while maintaining a compact size.

[0043] Figure 2 shows a conversion device 10 in one embodiment with panel or sheet, consisting of a single basic module, adapted to convert the thermic energy resulting from industrial processes into electrical energy. For simplicity, junctions 11,11 p, lln are not shown.

[0044] Preferably, ends 12 of each element P, N are provided, at the zone of contact with plates 14, 16, with a curvature radius (preferably convex) .

[0045] Preferably, plates 14, 16 are provided, at the zone of contact with each element P, N, with special seats having a certain curvature radius (preferably concave) corresponding to that of elements P, N.

[0046] The presence of such curvature radii on elements P, N, and/or on the plates, allows compensating for the microshiftings due to thermal expansion and improving the adhesion between elements P, N and the plates. Such an improved adhesion is critical to ensure proper heat transfer between plate and element P, N (or prism P, N) , and thus ensure an efficient operation of the conversion device 10.

[0047] Figure 3 shows a conversion device 10 in a variant embodiment with panel or sheet, wherein the panel comprises at least one attachment element 30.

[0048] The attachment element 30 is preferably a screw, adapted to be inserted in special holes 33 provided in both plates 14, 16.

[0049] Preferably, the screw attachment element 30 passes through both plates 14, 16 so as to firmly enclose the circuit of the elementary pairs 1,2,3, n (or pairs P-N) between the two plates 14, 16.

[0050] The attachment element 30 can be screwed into threaded holes 33, or stopped in position by bolts.

[0051 ] Preferably, the attachment element 30 comprises a spring 31, such as a coil spring or Belleville spring.

[0052] Spring 31 is fitted on the screw body before it is inserted into holes 33 of plates 14, 16. Once the screw attachment element 30 is inserted into hole 33 of the first plate, for example the lower plate 14, spring 31 remains compressed between head 34 of the screw and plate 14. The pressure exerted by spring 31 helps to improve the attachment of the conversion device 10 and the adhesion between elements P, N (or prisms P, N) and the plates .

[0053] Preferably, the conversion device 10 comprises a plurality of attachment elements 30, each provided with a spring 31.

[0054] In one embodiment, shown in figure 3, the attachment elements 30 are positioned along the edges of the conversion device 10, preferably at the corners.

[0055] Further attachment elements 30 are provided also at the centre of the conversion device 10.

[0056] In use, the conversion device 10, is positioned in the vicinity of production facilities and machinery that generate large amounts of heat. In this way, the plate facing the heat source (for example plate 14) is heated by heat generated by the production plants, while the opposite plate (for example plate 16) must be suitably cooled. Given the difference in temperature between the two plates 14, 16, inside the conversion device 10, suitably connected to an external electrical circuit (not shown), a direct current will flow.

[0057] The heating of the front plate takes place mainly by radiation, or for example with oil; the cooling of the opposite plate may be achieved using liquid or air.

[0058] Preferably, the conversion device 10 is modular. Examples of the basic modules of a conversion device 10 are shown in figure 2 and 3.

[0059] In one exemplary embodiment, a basic module of a conversion device 10 has an extension of one square metre, includes five elementary pairs P-N, and allows developing a power of approximately 10,000W, for a temperature difference ΔΤ of about 300 °C.

[0060] The basic modules of the conversion device 10 may be joined to form a single panel or a plate or a partition, or a wall, to be placed in the vicinity of production facilities and machinery that generate large amounts of heat. The basic modules can thus be joined to form a conversion assembly of thermic energy into electrical energy comprising a plurality of conversion devices 10.

[0061] An example of a modular composition of the basic modules of a conversion device 10 is shown in figure 6.

[0062] The basic modules of the conversion device 10 may be mounted on ducts, channels, cooling panels, or on heat sinks of various types, in order to increase the temperature difference ΔΤ between the two plates 14, 16.

[0063] Figure 4 shows a plurality of conversion devices 10 applied to a cooling duct 40. Figure 4 then shows a conversion assembly of thermic energy into electrical energy, comprising at least one conversion device 10 and a cooling duct 40. [0064] Duct 40, for example with a parallelepiped section, is composed of walls 42 that define an inner channel 41 for the transit of the cooling fluid.

[0065] At least one of walls 42 of duct 40 is provided with at least one conversion device 10. Preferably, all walls 42 of duct 40 are provided with at least one conversion device 10.

[0066] Each conversion device 10 is attached to wall 42 by attachment elements 30, preferably provided with a spring 31, inserted in holes 43 provided on wall 42.

[0067] Duct 40 provided with conversion devices 10 is positioned in the vicinity of production facilities and machinery that generate large amounts of heat. In this way, the outermost plates (for example plates 14) are heated by the heat generated by the production plant, while the plates in contact with walls 42 of duct 40 (for example plates 16) are suitably cooled, for example through air made to flow, more or less forcibly, within channel 41. Given the difference in temperature between plates 14, 16, inside each conversion device 10, suitably connected to a respective external electrical circuit (not shown) , a direct current will flow.

[0068] Figure 5 shows a conversion device 10 applied to a cooling panel 50, supplied with fluid. Figure 5 then shows a conversion assembly of thermic energy into electrical energy, comprising at least one conversion device 10 and a cooling panel 50.

[0069] Panel 50, for example in the shape of a parallelepiped, is provided with an inner chamber (51) to contain a cooling fluid, and at a rear wall 53, is provided with an input duct 55 and an output duct 56, respectively for the entry and the exit of the cooling fluid.

[0070] Panel 50 also comprises, inside chamber 51, a partition 54 adapted to divide the inner space so as to define, together with ducts 55, 56 a path to facilitate the circulation of the cooling fluid.

[0071 ] Panel 50, is also provided, at a front wall 54, with at least one conversion device 10.

[0072] Panel 50 provided with conversion device 10 is positioned in the vicinity of production facilities and machinery that generate large amounts of heat. In this way, the outer plate (for example plate 14) is heated by the heat generated by the production plant, while the plate in contact with wall 52 of panel 50 (for example plate 16) is suitably cooled, for example through water circulation made to flow, more or less forcibly, within chamber 51. Given the difference in temperature between plates 14, 16, inside the conversion device 10, suitably connected to an external electrical circuit (not shown) , a direct current will flow.

[0073] Figure 6 shows a plurality of panels 50, joined to form a single panel or wall or partition adapted to convert the thermic energy resulting from industrial processes into electrical energy.

[0074] Figure 7 shows a conversion device 10 whereto a heat sink 80 is applied. Figure 7 then shows a conversion assembly of thermic energy into electrical energy, comprising at least one conversion device 10 and a heat sink 80. The heat sink 80 is positioned on an outer plate (for example plate 16) of the conversion device 10.

[0075] The heat sink 80 includes a plurality of heat sink elements 81. Preferably, the heat sink elements are fins or plates made of metal.

[0076] The heat sink elements 81 are positioned alongside in parallel, substantially in a comb arrangement, so as to define a plurality of channels 82 suitable to convey a cooling fluid, for example an air flow.

[0077] The conversion device 40 provided with heat sink 80 is positioned in the vicinity of production facilities and machinery that generate large amounts of heat. In this way, the outer plate (for example plate 14) is heated by the heat generated by the production plant, while the plate provided with heat sink 80 (for example plate 16) is suitably cooled, for example through the circulation of an air flow which flows between the heat sink elements 81, conveyed within channels 82. Given the difference in temperature between plates 14, 16, inside the conversion device 10, suitably connected to an external electrical circuit (not shown) , a direct current will flow.

[0078] The conversion device 10 according to the present invention is particularly suitable for use in the foundry. In particular, the conversion device 10 is positioned in front of a casting, a chimney, or in billet store, all areas with a high temperature and which therefore concentrate the majority of the heat and the thermic energy produced during processing.

[0079] The conversion device 10 may be used in the shape of a panel, plate, partition, protective panel, cover.

[0080] The conversion device 10 may also be mounted on ducts, channels, cooling panels, or on heat sinks of various types.

[0081 ] Thanks to the conversion device 10 according to the present invention, the waste thermic energy can be recovered in the same moment in which it is dissipated, and this energy, once converted into electrical energy, can be used to supply the machines themselves and the plants, or for different ancillary functions.

[0082] Innovatively, the conversion device of thermic energy into electrical energy according to the present invention is particularly efficient and compact.

[0083] Advantageously, the use of Silver-Antimony-Tellurium for element P and Germanium-Tellurium for element N allows providing a conversion device of thermic energy into electrical energy with high efficiency.

[0084] Advantageously, the conversion . device of thermic energy into electrical energy according to the present invention allows the recovery of th.e heat produced by production facilities and manufacturing processes for the production of electrical energy.

[0085] Advantageously, the conversion device of thermic energy into electrical energy according to the present invention is not affected by microshiftings due to thermal expansion and therefore ensures an efficient operation of the conversion device even at high temperatures.

[0086] Advantageously, the conversion device according to the present invention can be used for the construction of panels, plates, partitions, walls, to be positioned in the vicinity of production facilities and equipment that generate large amounts of heat for the production of electrical energy.

[0087] It is clear that a man skilled in the art can make changes and variations to the anti-intrusion security system described above, all falling within the scope of protection as defined in the following claims.