ES2921483A1 - Thermoelectric module for the use of residual heat and industrial processes monitoring system (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Thermoelectric module for the use of residual heat and industrial processes monitoring system. The thermoelectric module includes heat collection means, energy generation means and heat dissipation means; And it is also provided with a structural base to act on pressure from the thermoelectric generator together with the dissipator and which has an opening by which the heat collector is likely to contact the surface of the heat source. There is also a system for monitoring industrial processes for predictive maintenance taking advantage of the residual heat comprising the aforementioned thermoelectric module. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Thermoelectric module for the use of residual heat and industrial process monitoring system

Technical sector of the invention

The present invention refers to a thermoelectric module for the use of residual heat, specially adapted to be installed on pipes or industrial surfaces, which act as a heat source. Thus, a new industrial process monitoring system for predictive maintenance is also presented, taking advantage of residual heat through the aforementioned thermoelectric module.

Background of the invention

Fossil fuels have been abused for many years as a means of obtaining energy, leading to severe consequences such as global warming of the world we inhabit. Fossil fuels are finite and to obtain, extract, transform or exploit them, among other inconveniences, emissions of gases harmful to the environment and living beings are generated.

Nowadays, human beings are becoming more and more aware of the need to protect the environment, researching and developing other energy sources, such as renewable energy sources. In addition to, for example, using energy in a more intelligent and sustainable way, avoiding wasteful consumption, making equipment more efficient to consume less; This type of renewable sources such as solar energy, wind power, geothermal energy and others are beginning to be implemented.

Among this type of developments to optimize energy resources, one of the emerging technologies, today, and addressed by the present invention is thermoelectricity. As its name indicates, thermoelectricity is a branch of physics in which the direct transformation of thermal energy to electrical energy or vice versa is studied. Although it was discovered years ago, more than 180 years ago, it is now regaining more interest in its application and exploitation for the optimization of energy resources.

Mainly, the interest of thermoelectricity is due to its ability to convert residual heat into electrical energy that can be a source of energy for other uses. Residual heat is the one that is wasted from some industrial process or not and that is not used later, but is emitted into the environment. It has a priori lower utility than the original energy source and can be considered a low energy level heat and this is where thermoelectricity is considered as a promising technology to recover lost heat and increase performance.

The pioneer of thermoelectricity was the German scientist Thomas Johann Seebeck (1770 1831). In 1822 he summarized the results of his experiments in the article "The Magnetic Polarization of Metal and Ores Produced by Temperature Difference". Seebeck experienced how the needle of a compass deflected if it was placed in the vicinity of a closed circuit formed by two conductors when one of their joints was heated. He erroneously concluded that the interaction was due to a magnetic phenomenon, and continuing with this belief, he tried to relate the magnetism of the earth to the difference in temperature between the equator and the poles. Although he was unable to correctly define the effect, Seebeck investigated the phenomenon in a large number of materials, including some of those we now know as semiconductors.

Years later, the Peltier effect was discovered in 1834, this is the complementary effect of the Seebeck effect. This effect occurs when a current passes through a circuit with two different conductors; depending on the direction of the current, the junction of the two conductors can either release heat or absorb heat. This effect was discovered by the French physicist Jean Charles Athanase Peltier (1785-1845). Like Seebeck, Peltier misinterpreted the results of his research by failing to assess the basis for his observations or to relate the effect to Seebeck's findings. Only in 1838 did Emily Lenz (1804-1865) prove that the Peltier effect was an autonomous physical phenomenon, consisting of releasing or absorbing additional heat at the junction of conductors when a current passed through them, and she demonstrated this by freezing water and returning melt the ice by reversing the direction of the current.

Twenty years later, William Thomson wrote a comprehensive explanation of the Seebeck and Peltier effects and described the relationship between them. Furthermore, he predicted the existence of a third thermoelectric effect, the Thomson effect, which he sequenced by observing experimentally.

This effect relates the heating or cooling in a homogeneous conductor in the presence of a temperature gradient when a current passes through it.

The discoveries triggered the development of a new field of engineering, thermal energy engineering, which studies the processes of converting thermal energy into electrical energy (Seebeck Effect;) and thermoelectric heating and cooling (Peltier Effect).

In the middle of the 20th century, thermoelectricity resurfaces due to the discovery of synthetic semiconductors with high Seebeck coefficients. But semiconductors were no better than metals, so interest waned. It was not until the 1950s, where compound semiconductors were obtained, obtaining thermoelectric improvements and stimulating possible military applications.

In the early 1960s, space exploration, as well as exploration of terrestrial resources in hostile locations, required autonomous electrical power sources. Thermoelectricity is presented as an ideal technology for these cases, since the absence of moving parts, its reliability and its silent operation offset its relatively high cost and low efficiency. For this reason, generators powered by radioisotopes were developed for the Apollo space program and for communications with the moon, from which most of the materials used in most current commercial generators would be derived.

Currently there has been a great increase in thermoelectric research due to the search for energy alternatives for scale production. Today, thermoelectric generators (known as TEGs) are made from a variety of semiconducting materials with varying results.

A thermoelectric generator is made up of one or several thermoelectric modules. Thermoelectric modules or Peltier cells (trade name) directly convert heat into electricity. Heat induces the circulation of an electrical current by flowing from a heat source through the thermoelectric generator (thermogenerator).

To generate electricity through the thermoelectric effect, a Peltier cell and a temperature differential between both sides of it are needed. Since current flow also generates heat, hot and cold sources have to continuously supply and dissipate heat to maintain that difference.

A Peltier cell is made up of two ceramic plates that serve as the base of the P-type and N-type thermocouples or thermoelements of semiconductor materials, also provides mechanical stability and serves as an electrical insulator.

A conventional module is made up of several thermoelectric pairs (semiconductor elements with P and N doping), electrically connected in series and thermally in parallel where there are free gaps, leaving both semiconductors connected through metallic bonds with high electrical conductivity. A Peltier cell is made up of 100 and 600 thermoelements.

These modules are silent, have no moving parts and do not require maintenance. In addition, its size and weight are low and can be used for a wide range of temperatures. However, they present an important disadvantage, their low efficiency.

This efficiency is linked to the semiconductor materials that form the thermoelectric couples and research is currently being carried out to improve it, but the process is slow. Therefore, to increase performance, the heat exchange systems found on both sides of the cell must be optimized to increase the electrical power generated. This is achieved in part as the temperature of the hot or cold source is similar to the source temperatures.

Taking into account the current state of the art, the objective of the present invention is to achieve a thermoelectric module that is capable of generating enough energy to power electronic devices or industrial sensors, taking advantage of the residual heat of the machine or process itself that is to be monitored.

Another objective of the present invention is to offer a new industrial process monitoring system for predictive maintenance taking advantage of residual heat by means of the thermoelectric module described in the present invention.

Explanation of the invention

In order to provide a technical solution for the use of industrial heat, especially for industrial pipes, and the growing need to monitor various parameters of the operation of machines and processes in the industry; A thermoelectric module for the use of residual heat is disclosed, specially adapted to be installed on pipes, ducts and industrial surfaces, comprising at least some means for capturing heat, some means for generating energy and some means for dissipating heat. heat. That with the associated electronics that will be presented later, allows this monitoring without the need for wiring or batteries.

In essence, the thermoelectric module is characterized in that the capture means comprise at least one heat sensor formed essentially by a prismatic piece of a thermally conductive material adapted to contact the surface of a heat source external to the module on one of its faces. thermoelectric, such as an industrial pipe, the power generation means, adapted for the transformation of heat into electrical energy, comprise at least one thermoelectric generator whose lower base is in contact with the heat collector, the heat dissipation means comprise at least one heat sink with a plurality of fins to absorb the maximum possible heat coming from the thermoelectric generator to which it is coupled, and is characterized in that it is also provided with a structural base of an essentially plastic material that provides the assembly with mechanical rigidity to act as pressure on the thermoelectric generator together with the heat sink and which has at least one opening through which the heat sensor is capable of contacting the surface of the heat source heat.

Advantageously, by placing said thermoelectric module on a pipe or surface, it is possible to take advantage of its residual heat for the generation of electrical energy that can be used in other devices. Through this configuration, it is achieved that, although the heat capture surface is small compared to the surface of the heat source, such as an industrial pipe, having the structural base protects the heat sink from the radiating heat of the heat source. heat and in turn works as a structural element that fixes all the components of the thermoelectric generation process, all of which increases the energy efficiency of the whole.

According to another characteristic of the invention, the thermoelectric module is characterized in that it also comprises at least one thermal joint between the heat sink and the structural base. According to a preferred embodiment, said thermal joint has at least one hole through which the thermoelectric generator contacts the heat sensor.

Advantageously, by means of this thermal joint, a safe seal is achieved once the thermoelectric generator has been assembled. In addition to working as a sealing element, it has two other functions: on the one hand, it must prevent the heat from the structural base from reaching the heat sink and contaminating it, worsening its operation; and, on the other hand, it has the objective of framing the assembly of said thermoelectric generator and fixing its position with the sensor.

According to another feature of the invention, the thermoelectric module is characterized in that the heat sensor is provided with at least one perimeter rim to rest on the structural base. Thanks to this perimeter rim, it is prevented that, at the moment of applying pressure to the thermoelectric generator through the structural base and the heat sink, these are expelled by the applied force; that is, it works in addition to support as a stop.

According to a preferred embodiment of the invention, the thermoelectric module is characterized in that the thermoelectric generator has at least one Peltier cell. This Peltier cell achieves from a temperature differential that is generated between its opposite surfaces, the one that contacts the sensor and the one that contacts the heat sink, a thermal energy that can be converted into electrical energy.

According to another feature of the invention, the structural base is provided with multiple ribs. As previously mentioned, an important component of the invention is the structural base, since its objective is to provide mechanical rigidity to act as a pressure system for the electric generator together with the heat sink. But on the other hand, it not only acts as a structural element, but also has the mission of acting as thermal insulation as indicated above, which is why a design with ribs is made, on the one hand, to support the efforts both of pressure to the thermoelectric generator as the pressure at the time of assembly in the heat source and on the other, to create hollow areas with the presence of air to use these spaces as thermal insulation against radiation and convection.

In a preferred embodiment of the invention, the thermoelectric module is characterized in that it also comprises at least two screws inserted through the lower part of the structural base and that have stops and washers that allow the depth to be controlled, acting as a spring and applying the force required for the thermoelectric generator to remain attached and in contact with the dissipator at the pressure force torque suitable for its correct operation. Advantageously, by means of this pressure screw, it is possible to reduce the surface roughness between the faces of the thermoelectric generator and the collector and heat sink, respectively, improving the heat transfer of the module.

According to another characteristic of the invention, the thermoelectric module is characterized in that it comprises an electronic box capable of housing inside it the electronics in charge of managing the electrical energy coming from the thermoelectric generator.

According to another aspect of the invention, with the aim of providing a solution for monitoring industrial processes for predictive maintenance taking advantage of residual heat, a system is disclosed characterized in that it comprises at least one thermoelectric module such as the one presented in this same section with previously, which generates enough energy to power electronic devices or industrial sensors of the machine itself that you want to monitor.

Advantageously, with this system of the invention it is possible to monitor any machine without supplying energy by using the residual heat of the machine itself or other residual sources of the environment where said system is applied.

According to another feature of the invention, the system is characterized in that it also comprises an IoT node to communicate and transmit the data obtained from the thermoelectric module, electronic device or industrial sensor of the machine being monitored.

In addition, according to a preferred embodiment, it is expected that the system comprises an analog control of the SoC power supply, connecting or disconnecting the system voltage to charge a supercapacity even if the energy generated is very low, such as lower than the consumption of the low-power operation. . Advantageously, this system achieves a very interesting solution for predictive maintenance in industrial environments, without requiring additional energy consumption.

Brief description of the drawings

In order to complete the description that is being made and in order to facilitate the understanding of the characteristics of the invention, a set of drawings is attached to this description, which illustrates, by way of example and not limitation, a way of realization of the thermoelectric module and the system of the invention. Specifically, the following is represented: Fig. 1 is a schematic exploded view of the thermoelectric module according to the invention; Fig. 2 is a schematic and perspective view of the thermoelectric module according to the invention;

Fig. 3 is a schematic and perspective view from a bottom viewpoint of the thermoelectric module of Fig. 2;

Fig. 4 is a schematic side view of the thermoelectric module of Fig. 2;

Fig. 5 is a schematic and perspective view of the thermoelectric module of Fig. 2 with the loT module of the system according to the invention;

Fig. 6 is a schematic view of the system according to the invention;

Fig. 7 is both schematic perspective and sectional views of the heat sensor of the thermoelectric module according to the invention;

Fig. 8 are perspective views from above, below and in section of the structural base of the thermoelectric module according to the invention;

Fig. 9 is a partial schematic view of the structural base of Fig. 8;

Fig. 10 is a partial schematic view of the structural base of Fig. 8;

Fig. 11 are respective schematic views of the thermal joint of the thermoelectric module according to the invention;

Fig. 12 are respective schematic views of the Peltier cell that make up the thermoelectric generator of the thermoelectric module according to the invention;

Fig. 13 are respective schematic views in perspective and partial installed on the structural base of the thermal joint of the electronic box of the thermoelectric module according to the invention;

Fig. 14 are respective schematic perspective views according to two points of view of the electronic box of the thermoelectric module according to the invention;

Figs. 15 and 16 are respectively schematic perspective views of a screw according to the invention and the three screws installed in the thermoelectric module of the example of embodiment according to the invention;

Figs. 17a, 17b, 17c, 17d, 17e and 17f are respective schematic views that facilitate understanding of how the capture means and generation means of the thermoelectric module according to the invention are mounted on the structural base;

Figs. 18a, 18b and 18c are respective schematic views of the sensors, the sensors with the Peltier cells and the assembly with the heat sink, respectively; Y

Figs. 19a and 19b are views of the electrical operation and block diagram of the control system.

Detailed description of the drawings

Fig. 1 presents a thermoelectric module 1 according to the invention for the use of residual heat, specially adapted to be installed on industrial pipes. To facilitate the understanding and identification of the different parts that make up this new thermoelectric module 1, it has been drawn schematically and separating each piece. As can be seen, the thermoelectric module 1 comprises heat capture means 2, power generation means 4 and heat dissipation means 5.

Specifically in this thermoelectric module 1, it can be seen that the heat capture means 2 comprise two heat sensors 21, each essentially formed by a prismatic piece of a thermally conductive material, such as a metallic material, adapted to contact on one of its faces, the lower flat surface 24, with the surface 35 of a heat source 3 (in Figs. 4, 6 and 18c that heat source 3 is represented).

In addition, the power generation means 4 of the aforementioned thermoelectric module 1 and which are adapted to transform heat into electrical energy, comprise two thermoelectric generators 41 whose lower base 42 is in contact with the sensor 21 (Figs. 16, 18b and 18c).

It can also be seen in the thermoelectric module 1 represented in Fig. 1 that the heat dissipation means 5 comprise a heat sink 51 with a plurality of fins 52 to absorb as much heat as possible coming from the thermoelectric generator 41 to which it is coupled.

In addition to said heat capture means 2, the energy generation means 4 and the heat dissipation means 5, the thermoelectric module 1 is also provided with a structural base 6 made of an essentially plastic material that provides the assembly (with components of the aforementioned module) of mechanical rigidity to act as pressure on the thermoelectric generator 41 together with the heat sink 51 and which has two openings 61 through which the heat sensor 21 is capable of contacting the surface 35 of the heat source 3 .

The component called heat collector 21 of the heat collection means 2 has the objective of capturing the maximum thermal flux that occurs in contact with the heat source 3. This component allows the transfer of heat by conduction from the heat source 3 up to the upper flat surface 23 on which the lower base 42 of the thermoelectric generator 41 rests. In this example, the thermoelectric module 1 is configured with two heat collectors 21 and two thermoelectric generators 41. Each heat collector 21 consists of a piece of metallic material, such as an aluminum-based alloy, because a high conduction heat transfer coefficient is needed and metallic materials have this highest value. In addition, this piece that forms the heat sensor 21 has two wings 25 which are to fix the piece to the structural base 6 through two screws 26 for plastic. On the other hand, as can also be seen in other figures such as Figs. 7, 16, 17c, 18a, 18b and 18c, the heat collector 21 has a perimeter rim 22 that serves to rest and function as a stop on the structural base 6 and prevent the thermoelectric generators 41 from applying pressure. through the mentioned structural base 6 and the dissipator 51, these are expelled by the applied force. This piece that forms the heat sensor 21 has a flat surface on both faces 23, 24 and this is to facilitate assembly and heat transmission on flat surfaces. In any case, it is anticipated that in the case of heat sources 3 with round tubular surfaces, there will be two holes 27 (Figs. 3, 7 and 16) for coupling adapters, not shown, to this type of surfaces. In addition, and in order to guarantee sealing once the sensors 21 have been assembled, they have a high-temperature O-ring type O-ring 28 made, for example, of an inorganic polymer such as silicone. Said gasket 28 is coupled at the bottom of the perimeter rim 22 as can be seen in Fig. 7. The O-ring acts as a static seal for the triangular groove where it rests.

The component called thermoelectric generator 41 of the power generation means 4, which is provided with two Peltier cells 41', are intended to convert thermal energy into electrical energy from the temperature differential that occurs between both surfaces of said cells Peltier 41'. That is, the Peltier effect will absorb heat from the hot side that is in contact with the heat collector 21 and will dissipate it from the cold side that is in contact with the heat sink 51. This heat flow will depend on the type of cell chosen. In a way known in itself, and as briefly described in the background of the present invention, this heat flow produces a Joule effect and combined with the Thomson effect, the Seebeck effect is originated, appearing an electromotive force that generates a current and therefore the electrical energy that is intended from the residual heat of this heat source 3. For the example shown here, a Peltier cell 41' provided with two Al2O3 ceramic plates, BiTe3 material pellets, aluminum conductor, two black and red Teflon cables, and perimeter silicone as a sealing gasket. The total number of thermocouples present in this thermoelectric generator 41 is a quantity of 199 thermocouples (398 pellets).

The component called dissipator 51 of the heat dissipation means 5 has the objective of absorbing the maximum possible heat that comes from the source with the highest temperature, which in this case is the hot surface of the thermoelectric generator 41, that is, the upper surface of the Peltier cells 41', and transfer this heat to the environment, which in this case is the air or industrial atmosphere 34. To make this process possible, it is necessary that the material of the heat sink 51 has good thermal conduction and the existence of a plurality of fins 52, in this case straight, although they could be corrugated to increase the contact surface with the environment, allowing a faster elimination of excess heat by means of natural convection. The heatsink 51 used in the example described here is designed to have a horizontal orientation or with the fins vertical, considering that the fins must have the same direction as the air flow. This heatsink 51 is expected to have three threaded holes to exert pressure on the Peltier cells 41'. It is contemplated that it may be made from an aluminum alloy and be natural anodized for surface protection against adverse conditions.

All these components are supported by the structural base 6 which, as has been mentioned before, provides the assembly with mechanical rigidity to exert pressure on the Peltier cells 41' together with the heat sink 51. On the other hand, it not only acts as a structural element, It also has the mission of acting as thermal insulation. This is because the heat source 3 emits heat in the form of radiation and convection and could contaminate the heat sink 51 increasing its temperature and causing thermal collapse if nothing is done. That is why this component is installed, to act as a screen avoiding heat by radiation and convection as this structural base 6 is made of a plastic material. Although this does not prevent the component from heating up, in fact, its temperature increases, on the one hand, due to the heat emitted by the source and, on the other, due to heat transfer by conduction coming from the heat collectors 21. All these situations cause its temperature to increase, but not considerably, since a thermal joint 7 is installed on top of the structural base 6, which also acts as an insulator. Therefore, the largest thermal flow by conduction is produced by the heat collector 21, the thermoelectric generators 41 or Peltier cells 41' and the heat sink 51 as can be seen in Fig. 18c. If you look at Fig. 8, you can see the lower part of the structural base 6. This component, being a plastic, can be manufactured by injection, so the part should not have very thick areas. That is why a design with ribs 62 is made, on the one hand, to support both pressure stresses to the thermoelectric generators 41 or Peltier cells 41' and the pressure at the time of assembly in the heat source 3 and on the other, create hollow areas with the presence of air to use these spaces as thermal insulation against radiation and convection. Air, as is well known, is one of the best insulators in the world and this helps ensure that the thermal path is only through the sensor and the cells, and does not increase the energy that the heatsink has to dissipate, causing the temperature that reaches the component has a greater decrease. The plastic material that has been used in the example has three holes for the insertion of three screws 8 that exert pressure on the thermoelectric generators 41 or Peltier cells 41'. Furthermore, as can be seen in Figs. 8, 9 and 10, which has a hole for fixing an electronic box 9 with two plastic screws, not shown, and two holes for each heat sensor 21. On the sides, the mentioned structural base 6 has a geometry to easily insert warning labels with a square hole and a slotted with two holes for the insertion of two screws in case the installation is done on a flat surface or the flat slotted for mounting a metal clamp for circular duct.

The thermal joint 7, represented in Fig. 11, has the purpose of fulfilling three objectives, the first and most important is to act as a sealing joint between the heat sink 51 and the structural base 6 in order to prevent water, humidity or dust can seep into the interior of the equipment and damage all the electrical components such as the thermoelectric generator 41 or Peltier cell 41' or the same electronics that are housed inside the electronic box 9. If the sealing is not occurs, there is a very high probability that there are failures due to short circuit and oxidation in the union of electrical components. That is why this gasket is made of an elastomeric material with the ability to deform when a pressure force is applied to it and its own deformation adapts to the surface in contact, resulting in no element being able to leak through it. The second objective that this piece must meet is to act as thermal insulation. Being in contact with the structural base 6 and in the same way the mentioned structural base 6 receives the heat from the heat source 3, it causes heat transfer by conduction. Consequently, a material of the elastomeric plastic type is chosen, and it also has a low thermal transfer coefficient by conduction, withstanding up to 200°C continuously and 250°C in short periods of operation. Therefore, the union of two insulating components, such as the structural base 6 and the thermal joint 7, are sufficient to prevent residual heat from reaching the heat sink 51 and causing a decrease in its thermal performance. And, as a third objective, it has the purpose of acting as a framing element when mounting the thermoelectric generators 41 (Peltier cells 41') on the heat collector 21. This means that the Peltier cells 41' (in the represented example of the figures) are assembled in the square geometry present in the hole-shaped piece, preventing it from moving when exerting pressure through the tightening screws 8. In addition, it has a groove where their respective cables are directed towards a hole that leads to the electronic box 9.

In a similar way to the thermal joint 7, it is foreseen that the thermoelectric module 1 has a second thermal joint, the thermal joint 77 of the electronic box 9, which has the objective of acting as a sealing element against atmospheric agents and as an element of thermal insulation to prevent failures due to short circuits and/or oxidation of the electrical components that make up the electronic box 9.

The electronic box 9, whose mission is to house inside the electronics in charge of managing the electrical energy coming from the thermoelectric generator 41. The power electronics is made up of a DC/DC converter with a Start-up voltage of 0.225V, and an MPPC so that the input voltage does not drop below 0.4V. And an output voltage of 5V. Converters with higher and lower Start-up voltages, with MPPT, and with higher and lower adjustable outputs have been used in other variants also included in the present invention. Given that the system needs or may need energies higher than those generated by the thermoelectric generator 41 for its operation, the energy is accumulated in a super capacity (usually 5F). The accumulated energy depends on the voltage and the capacity, more voltage implies being able to use a lower capacity. Given that at low temperatures the energy generated is very low, around 1mW, it is important that the system is turned off until it has enough energy to carry out an entire work cycle (from data acquisition to sending). The power control part is responsible for ensuring that until enough energy has been accumulated, the monitoring part does not consume anything (it has no voltage), cutting off the power supply. This has two advantages: the first is that since there is no consumption by the electronics, all the energy generated is accumulated in the capacity. The second is that it prevents possible erroneous operations due to a slow rise in voltage, or unstable operation as a result of which consumption increases, erroneously using the accumulated energy. The system generates two programmable limits, the one on (normally 4.5V), and the one on off, which depends on the function of the device (normally 3.7V). These minimum turn-on voltages are represented in Fig. 19a and in Fig. 19b the operation according to the stages X3, X1, X2 that feed the SoC. The programming of these voltages depends on two resistors. These on and off values will depend on the operating voltage of the system, typically 3.3V, 2.5V or 1.8V. Being a system that generates its own energy and does not depend on a battery, it allows use with Edge-Computing algorithms without affecting the life of the device. What It allows certain analyzes without the need to send a lot of data with the savings of communications, and avoiding a saturation of the radio spectrum.

As has been shown, the pressure that exists between all the components is vital for proper operation and maximum optimization of the energy performance of the thermoelectric module 1. Thus, the pressure system of the thermoelectric generator 41 is described below, in concrete for Peltier cells 41', which in this example consists of three special screws 8 that facilitate installation and reduce assembly time. This system consists of machine screws 8 and two washers 82 as can be seen in Fig. 16. Each screw 8 in the example is made of steel and has a pin diameter of 6mm and a thread of M5. This makes it possible to create a stop 81 at the end of the pin that prevents further threading. In the case of the system, the stop 81 prevents further threading in the heatsink 51 and applying more force than it should. Peltier 41' cells need a pressure torque to reduce surface roughness, so it is recommended to use a pressure force of 1MPa to 1.2Mpa per Peltier 41' cell, in this case. From the dimensions of the Peltier cells 41' and the pressure, the force to be applied to the screws 8 can be determined. In order to ensure said force, special washers 82 called Belleville are used, which exert a constant pressure on the surface support. Said Belleville-type washers 82 have a concave shape that allows a deformation to be applied and a residual elastic force to be obtained. Depending on the force required, more than one washer 82 may be combined in the same direction to add forces.

By means of this thermoelectric module 1, according to the invention, an industrial process monitoring system is configured for predictive maintenance taking advantage of residual heat, as can be seen in the example shown in Fig. 5. This system comprises the thermoelectric module 1, a node loT 10 and the sensor (vibration and/or temperature). In other words, the system by means of the aforementioned thermoelectric module 1 is capable of generating enough energy to power electronic devices 11, such as, for example, industrial sensors of the machine itself that is to be monitored (see Fig. 6).

At a functional level, the system of the example represented has two Peltier cells 41' per generation unit, which means that the larger the surface, the energy generation that can be used will be. The thermoelectric module 1 follows the process of operation of this type of energy transformation: capture, generation and dissipation. As has been presented previously, the components that will be located in each of them have been studied and calculated to obtain the best possible performance.

In the capture process, the thermoelectric module 1 will capture the largest residual heat flow by contact with the surface that emits a heat source 3 through the heat capture means 2. In the thermoelectric module 1 of the present example there are two collectors 21 for two Peltier cells 41' that are located on the surface with the geometry of the Peltier cell 41' of 40x40 mm. The collected heat that passes through the collector 21 reaches one of the Peltier cells 41' (Thot, hot temperature) and then, by causing a thermal differential on the rear face (Tcold, cold temperature), it begins to generate electrical energy . This cell, such as the TGM-199-1.4-3.2 from the manufacturer Kryotherm, is capable of generating 5.9W of electrical power with a temperature differential between faces of 170°C with a maximum working temperature of 200 °C The thermal differential on the Tcold face of the Peltier cell 41' is caused by a heat exchanger or thermal sink 51 with straight fins 52 of the passive type. This component extracts the heat that passes through the Peltier cell 41' and dissipates it through its fins 52 in the form of radiation or is absorbed by the surrounding fluid through convection (this fluid in this case is the air of the industrial atmosphere). where the system is installed). This dissipated heat causes the surface Tcold of the Peltier cell 41', which is in contact with the heat sink 51, to cool, causing a differential of temperature between the surfaces of said Peltier cell 41'. Therefore, the Peltier cell 41' remains as a 'sandwich' between the sensor 21 by contact and the fins 52 dissipator 51 as can be seen in Figs. 1 2 and 3.

The capture surface by the collectors 21 is small compared to the surface of the heat source 3, this causes the heat emitted by the source to be absorbed by the thermoelectric module 1 and cause a decrease in both thermal and electrical performance . That is why, to avoid this situation, an insulating component is installed to protect the heat sink from the radiating heat of the heat source and, in turn, works as a structural element that fixes all the components of the thermoelectric generation process, that is, the aforementioned structural base 6 described above.

With this configuration, a product that is durable and resistant to temporary wear and tear in the work environment is achieved, especially intended for industrial environments. This resistance includes corrosion resistance for more than 5 years of operating life, resistance to ultraviolet radiation for more than 5 years of operating life, resistance to chemical attack for more than 5 years of operating life, and watertightness against to humidity, water and dust with IP67 protection.

Through the combination of the structural base 6 and the different fixing elements, such as the screws 8, the thermoelectric module 1 of the invention is robust enough to resist blows without deforming or breaking, its fracture toughness is greater than 25Mpa mA0.5.

The idea of the inventors has always been to achieve a solution that is easy and quick to install in terms of time without complicated operating assemblies, this has been achieved as can be seen in this example in which the entire thermoelectric module 1 is solidly joined and so it should only be fixed to the surface 35 of the heat source 3 and connected to the rest of the elements that make up the system, such as the sensors of the machine to be monitored. The product has to remain fixed and static for its correct operation and for this reason it is anchored and/or fixed by means of tightening components in a way known in itself.

It has not been the object of this report to spend time mentioning the exact measurements of the thermoelectric module 1 or of the system of the invention, but as can be deduced its dimensions are discrete and do not interrupt internal processes due to size or functionality of the rest of the industrial installation where the invention is installed. As a guide, the thermoelectric module 1 of the example has the following dimensions: 220x100x100 mm.

In order to respect and not affect the rest of the regulations on the prevention of occupational risks of the industrial facility where it is installed, it is expected that both the thermoelectric module 1 and the elements that intervene with the system of the invention are correctly marked to avoid the interruption by third parties without authorization and cause unforeseen damage to both the equipment and the operator who could intervene, especially the hot surface will be clearly marked.

The shape of the thermoelectric module assembly 1 as seen in the drawings is approximately a prism, an attempt has been made to achieve an aesthetic that defines its shape through its functionality, taking into account that its aesthetics should not interrupt its performance.

At an electrical level, the energy generated does not affect the operation of the associated electronics, but it has an effect on the lack of energy accumulation, which will limit how often data acquisition and its pertinent analysis can be made before sending them.

It follows that, being mainly in industrial environments, temperature is a relevant aspect to take into account, thus the thermoelectric module 1 of the invention has been designed to be able to withstand working temperatures between -10°C and 50°C and temperatures operating between 50°C and 180°C.

In the same way that it was desired to offer an easy-to-install solution, it was also desired to achieve a solution that would minimize the manufacturing process and the parts or components that make up the equipment. Although schematic in the drawings, combined with the present description, it can be noted that this goal has been achieved with a solution having less than 20 parts. In addition, the assembly and assembly of all the elements is reduced in complexity and time as all the details have been very well adjusted in this regard. At the level of direct manufacturing costs, it has been planned to use materials and elements available on the market without investing money in the creation of new materials or elements, but more time has been invested in a correct selection and triage of the most suitable materials. for these uses. Even so, some of the pieces are made-to-measure pieces, such as the structural base 6 and the collectors 21.

The thermoelectric module 1 of the example is part of a new industrial process monitoring system for predictive maintenance taking advantage of residual heat, specifically the residual heat of the pipes 33 represented schematically in Figs.

4, 6 and 18c. This thermoelectric module 1 of this system obtains enough energy to power the electronic device 11 or industrial sensor of the machine itself that is to be monitored.

The system also comprises an IoT node 10 to communicate and transmit the data obtained from the thermoelectric module 1, electronic device 11 or industrial sensor of the machine being monitored.

Thus, a system for predictive maintenance is achieved that does not require additional energy for its operation. Only with the residual heat of the installation itself, such as that obtained from the surface of the pipes, is it supplied with sufficient energy.

Finally, the inventors consider that the reader of this description may conclude that although an example has been described for an industrial environment and in fact it is basically the use that is considered to be more widespread, it is not ruled out that it can be used for non-industrial environments. industrial, in which essentially the same technical characteristics described here could be maintained.

Claims (11)

1. Thermoelectric module (1) for the use of residual heat, specially adapted to be installed on industrial pipes, comprising at least some heat capture means (2), power generation means (4) and heat dissipation means. (5), characterized in that: - the heat capture means (2) comprise at least one heat sensor (21) formed essentially by a prismatic piece of a thermally conductive material adapted to contact the surface of a heat source (3) on one of its faces external to the thermoelectric module (1); - the energy generation means (4), adapted for the transformation of heat into electrical energy, comprise at least one thermoelectric generator (41) whose lower base (42) is in contact with the heat sensor (2); - the heat dissipation means (5) comprise at least one heat sink (51) with a plurality of fins (52) to absorb as much heat as possible coming from the thermoelectric generator (41) to which it is coupled; Y - because it is also provided with a structural base (6) of an essentially plastic material that provides the assembly (of components of the aforementioned module) with mechanical rigidity to act as pressure on the thermoelectric generator (41) together with the heat sink (51) and the which has at least one opening (61) through which the heat sensor (21) is capable of contacting the surface of the heat source (3). 2. Thermoelectric module (1) according to the preceding claim, characterized in that it further comprises at least one thermal joint (7) between the heat sink (51) and the structural base (6). Thermoelectric module (1) according to the preceding claim, characterized in that the thermal joint (7) has at least one hole (71) through which the thermoelectric generator (41) contacts the heat sensor (21). 4. Thermoelectric module (1) according to any one of the preceding claims, characterized in that the heat sensor (21) is provided with at least one perimeter rim (22) to rest on the structural base (6). Thermoelectric module (1) according to any one of the preceding claims, characterized in that the thermoelectric generator (41) is at least one Peltier cell (41'). 6. Thermoelectric module (1) according to any one of the preceding claims, characterized in that the structural base (6) is provided with multiple ribs (62). 7. Thermoelectric module (1) according to any one of the preceding claims, characterized in that it further comprises at least two screws (8) inserted through the lower part of the structural base (6) and having stops (81) and washers (82) that allow the depth to be controlled, acting as a spring and applying the force required for the thermoelectric generator (41) to remain attached and in contact with the heat sink (51) at the pressure force torque suitable for its correct thermal operation. 8. Thermoelectric module (1) according to any one of the preceding claims, characterized in that it comprises an electronic box (9) capable of housing inside it the electronics responsible for managing the electrical energy from the thermoelectric generator (41). 9. Industrial process monitoring system for predictive maintenance using residual heat, characterized in that it comprises at least one thermoelectric module (1) according to any one of claims 1 to 9 that generates enough energy to power electronic devices (11) or industrial sensors of the machine itself that you want to monitor. 10. Monitoring system according to the preceding claim, characterized in that it further comprises an IoT node (10) to communicate and transmit the data obtained from the thermoelectric module (1), electronic device (11) or industrial sensor of the machine being monitored. 11. Monitoring system according to the preceding claim, characterized in that it comprises an analog control of the SoC power supply, connecting or disconnecting the system voltage to charge a supercapacity even if the energy generated is very low, such as lower than the consumption of low power operation. consumption.