RU2788056C2 - System for temperature control and for creating an air flow in an electric casing - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: present invention relates to a system for temperature control and for creating an air flow in an electric casing. The invention also relates to an electrical casing that includes the mentioned system. The system for controlling the temperature and for creating an air flow in the electric casing includes an air duct (40, 400) containing at least the first hole, the second hole and a channel located between the said first hole and the said second hole (41, 401) in order to make it possible for the said air flow to pass between the two holes, a lattice (20) of a set of independent thermoelectric modules (M). The mentioned lattice contains at least one aligned subset of the set of thermoelectric modules, which is located in a direction called the main direction oriented along the said channel, and each lattice module has one side inside the duct and one side outside the said duct. The temperature control system also contains a control unit (UC), made with the ability to control each thermoelectric module of the lattice in an individualized manner. The electrical casing includes a set of walls limiting the internal volume intended for receiving electrical or electronic devices, characterized in that it includes the mentioned system for temperature control and for creating an air flow.

EFFECT: as a result, it is possible to do without classical ventilation, cooling and/or heating systems, the risks of failures are reduced, damage to electrical or electronic devices enclosed in an electrical cabinet is prevented.

12 cl, 13 dwg

Description

Field of invention

The present invention relates to a system for controlling temperature and for generating airflow in an electrical enclosure. The invention also relates to an electrical enclosure comprising said system.

State of the art

At present, it is difficult to find one single solution for controlling the temperature inside an electrical cabinet. In fact, the situation may be different depending on the type of electrical or electronic devices that are placed in the electrical cabinet, depending on the environment in which the electrical cabinet is placed, because it can be placed in a dedicated room, outdoors, in a hot environment, in a cold environment or in an environment with changing temperature.

For example, if an electrical cabinet is used outdoors, it may be useful to control the temperature inside the cabinet, whether it is necessary to cool the devices in case of high ambient temperatures or to heat the interior of the electrical cabinet to remove moisture.

In order to adapt a cabinet to its environment, it is well known to include a ventilation system including one or more fans, a cooling system including an air conditioner, and/or a heating system that may use a heating element or an air conditioner. in reverse mode.

However, apart from the fact that it is necessary to know the conditions in which the electrical cabinet will be placed, some of these systems are often prone to failure. In electrical cabinets, failures often occur in one of the above systems. By way of example, a prolonged interruption of the ventilation system can lead to risks of overheating inside the electrical cabinet and therefore to the risk of damage to the electrical or electronic devices that are installed in the electrical cabinet.

The object of the invention is to propose a solution that makes it possible to dispense with the above-mentioned classical ventilation, cooling and/or heating systems in order to limit the risks of failure and thereby prevent possible damage to the electrical or electronic devices contained in the electrical cabinet.

The essence of the invention

The above problem is solved by a system for controlling temperature and for creating an air flow in an electrical enclosure, including:

- an air duct containing at least a first opening, a second opening and a channel located between said first opening and said second opening in order to allow said air flow to pass between the two openings,

– a grid of many independent thermoelectric modules,

wherein said array contains at least one aligned subset of the plurality of thermoelectric modules, which is located in a direction called the main direction, and each thermoelectric array module has two opposite sides and is addressed in an individualized manner in order to create a Peltier effect between its two sides,

wherein said array of modules is positioned so as to orient its aligned subset of the plurality of thermoelectric modules along said duct, and each array module has one side inside the duct and one side outside of said duct,

- a control unit configured to control each thermoelectric module of the grid in an individualized manner.

According to one specific feature, all thermoelectric modules are identical.

According to one particular implementation, the array of modules includes a plurality of thermoelectric modules arranged in a plurality of rows and at least one column, each row of thermoelectric modules being given a rank of i, where i is from 1 to n and n is greater than or equal to 2 , and each column of thermoelectric modules is given a rank j, where j is from 1 to m, and m is greater than or equal to 1.

According to another specific feature, the control unit is configured to address each array module at its coordinates i, j in the array.

According to another specific feature, the thermoelectric modules are arranged in the array in such a way as to form a quasi-continuous surface.

According to another specific feature, said surface is flat.

According to another specific embodiment, the air duct is formed by a tube having at least one wall delimiting said channel, and said tube wall forms a support for said grid.

According to one specific feature, the control unit includes a module for determining which thermoelectric modules should be temperature controlled depending on the direction and importance of the airflow generated in the duct.

According to another specific feature, the control unit includes a module for determining the temperature of each thermoelectric module, taking into account the orientation of the air flow and the intensity of the generated air flow.

According to another specific feature, the duct includes at least one wall formed by the wall of the electrical enclosure.

According to another specific feature, the system includes a valve that can be commanded to partially or completely block each opening.

The invention also relates to an electrical enclosure including a plurality of walls delimiting an internal volume for receiving electrical or electronic devices, said enclosure including the temperature control and airflow system described above.

Brief description of the drawings

Other features and advantages will become apparent from the following detailed description with reference to the accompanying drawings, in which:

Fig. 1 is a schematic representation of the construction principle of the system according to the invention for use in an electrical cabinet;

Fig. 2A and 2B are side views of a thermoelectric module that can be used in the system according to the invention;

Fig. 3A-3F show a first embodiment of the system according to the invention and the principle of its operation;

Fig. 4A and 4B show another embodiment of the system according to the invention in perspective and in cross section, respectively;

Fig. 5A and 5B show two other embodiments of the system of the invention.

Detailed description of at least one embodiment

Referring to FIG. 1, an electrical enclosure 1 is taken as an application in the form of a parallelepiped-shaped electrical cabinet comprising a top wall 10, a bottom wall 11 and four side walls 12 arranged in pairs opposite each other. Of course, the system according to the invention can be adapted to all types, all shapes and all sizes of the electrical enclosure.

The electrical cabinet 1 is designed to contain electrical and/or electronic devices 6 mounted on rails 7, for example, and may include an air inlet (not shown) through which air is introduced into the interior of the electrical cabinet 1, and an air outlet (not shown) to exhaust hot air outside the electrical cabinet 1. However, the invention would be ideal for an electrical cabinet that is said to be airtight, in other words, no air inlet and no air outlet.

The system according to the invention may allow:

– create at least one air flow in the electrical cabinet 1 in a given direction;

– locally cool or heat certain areas inside the electrical cabinet 1.

By creating an air flow, the air can therefore circulate in the electrical cabinet, in particular enabling:

– temperature homogenization in the cabinet;

– air inlet into the cabinet and/or its removal to the outside;

– elimination of a “hot spot” (place of localized overheating) or “cold spot” (place of localized underheating) by directing the air flow appropriately to the “hot spot” or “cold spot”.

The system according to the invention includes a grid (matrix) 20 containing a plurality of thermoelectric modules (Peltier modules). The grid 20 may include a support 200 on which the thermoelectric modules M are assembled and organized.

The thermoelectric modules M may be identical.

Within the array, the thermoelectric modules M can be positioned in an adjacent and adjoining manner, forming a quasi-continuous surface. The surface can be flat or curved depending on the shape and layout of the modules. The surfaces of two adjacent lattice modules would ideally be separated from each other by a heat insulating element to prevent heat transfer from one module to the other.

Referring to FIG. 2A and 2B, each thermoelectric module M has a conventional internal structure 30 containing semiconductor chips made of N-type and P-type bismuth telluride materials. On each side, this structure is covered by two ceramic plates 31 and 32 having high thermal conductivity. The string of chips is electrically connected in series but thermally parallel to optimize heat transfer between the hot and cold ceramic surfaces of the module. In the modules shown in the attached figures, light gray represents the so-called cold plate and dark gray represents the so-called hot plate. Applying current to module M allows heat to be absorbed or released. When a DC voltage is applied by the generator 33, the positive and negative charge carriers absorb heat from the surface of the substrate and transfer it and release it to the substrate on the opposite side. Consequently, the surface on which energy is absorbed becomes cold, and the opposite surface, on which energy is released, becomes hot. It is also possible to modify the direction of heat flow within the module by simply reversing the direction of the current. This last principle is shown in Fig. 2A and 2B, in which it can be seen that reversing the direction of the current provides a reversal of the direction of heat flow between the two plates 31, 32.

The two ceramic plates 31, 32 may have a rectangular format, identical and superimposed on respective opposite sides of the internal structure 30 of the module, delimiting the outer contour of the module. Any other form may be provided.

The system includes a control unit UC designed to control each thermoelectric module M in an independent and individualized manner.

Each thermoelectric module M can be controlled directly by the control unit UC using a point-to-point connection (shown by each arrow in FIG. 1) by supplying an appropriate electrical current to it and applying an appropriate electrical voltage. The electrical connections allow each M module to be connected to the UC control unit. Of course, it should be understood that any other communication and control solution (bus, wireless connection, etc.) may be contemplated.

The UC control unit may include a module for controlling the temperature of each module depending on the input electrical power.

Temperature sensors T can be placed inside and outside the electrical cabinet 1, each of which is connected to the control unit UC in order to supply it with temperature measurement data. The temperature measurement data can be processed by the UC control unit in order to manage each grid module properly.

The electric power supply current of each thermoelectric module M is characterized by its direction and its strength. This direction actually allows the direction of heat flow between the two plates 31, 32 of module M to be orientated, and thus the assignment of the cold side and hot side of the module. The amount of current controls the temperature level of each side of the module, these temperatures being referred to as TA and TB for the A and B sides of the M module, respectively.

The system according to the invention includes an air duct 40, 400 defining a channel 41, 401 through which the system generated air flow F10, F20, F30, F100 can circulate. The duct includes at least two openings 42, 43; 402, 403, between which said channel is formed and delimited by at least one side wall 44, 404 comprising an inner side located inside the air duct 40, 400 and an outer side located outside the air duct. These two holes, for example, are located at two opposite ends of the lattice. It is equally possible to provide other openings, in particular side openings through said side wall. These side openings 46, 48 may be provided at the two ends of a transversely aligned subset of the array modules, as can be seen in FIG. 3B, or through the grating support and directly between the two grating modules, as can be seen in FIG. 3E.

According to one particular aspect of the invention, the support 200 of the grille 20 may be positioned so as to at least partially form said duct side wall, with at least one aligned subset of the thermoelectric modules M of the grille 20 therefore oriented along the channel 41, 401. Therefore, one of two sides of the grille 20 is on the inside of the duct wall, and the other side of the grille is on the outside of the duct wall.

Since each thermoelectric module M has two sides intended to have different temperatures, two different temperatures are assigned to it: the first temperature TA_i,j corresponding to the temperature of its inner side intended to be located inside the duct, and the second temperature TB_i,j corresponding to the temperature of its outer side, designed to be located outside the duct.

Without imposing restrictions on the invention, said air duct can be made inside the electrical cabinet 1. It can be made in the form of a single (solid) unit installed directly in the space of the electrical cabinet 1 (as shown in Fig. 3A-3D), or it can use one or more existing walls of the electrical cabinet to complete the wall supporting the grid of thermoelectric modules. The grid can equally replace the wall 10, 11, 12 of the electrical cabinet, orienting one of its sides outside the electrical cabinet, and the other side inside the electrical cabinet. Then the duct is formed by the complementary part located in the electrical cabinet 1. Therefore, FIG. 5A and 5B show two possible implementations of the system according to the invention. In FIG. 5A, the air duct uses the electrical cabinet wall 12 to form part of its side wall. In FIG. 5B, the grate 20 and its support 200 replace the side wall 12 of the electrical cabinet, having one side of the modules inside the electrical cabinet and the other side of the modules outside the electrical cabinet. Complementary wall 50 is placed inside the electrical cabinet, completing the side wall of the duct.

In one particular feature, each opening can be controlled by a valve 47, 407 which can be controlled by a control unit to open or close it. The position of each valve can also be controlled by the UC control unit in such a way as to control the rate of airflow generated.

More specifically, two different embodiments of the system according to the invention can be distinguished because of this.

In the first embodiment shown in FIG. 3A-3F, the array of thermoelectric modules 20 takes the form of a wall that is flat on its two sides, each of which is formed by a quasi-conjugate alignment (ordering) of a plurality of thermoelectric modules. This module wall is formed to form one of the air duct walls, thereby providing the formation of the inner side of the air duct wall and the outer side of the air duct wall. At least one airflow F10 is generated along an aligned subset of modules by natural convection, from the module with the coldest interior to the module with the hottest interior. This principle is illustrated in Fig. 3A and 3B. The second airflow F20 can also be created between the second aligned subset of the grille modules, between the two side duct openings 46 . The two openings 42, 43 can then be closed by valves 47. This principle is illustrated in FIG. 3C and 3D. Similarly, FIG. 3E and 3F show the creation of an airflow F30 between one of the openings 42 and an opening 48 made straight through the support 200 of the module grid. The last solution should be useful in order to deal with the "hot spot" in the closet. Then all other openings can be blocked by a properly controlled valve. Other openings of this type may be provided through the grille support 200 and even through the entire side wall of the device for better adaptation of the air flow direction in the electrical cabinet.

Without limiting the invention, if the array 20 is rectangular and includes a plurality of aligned subsets of thermoelectric modules in rows and columns, each thermoelectric module can be identified by coordinates i,j, where i corresponds to the row number, where i is from 1 to n (n is greater than or equal to 2), and where j corresponds to the column number, and j is from 1 to m (m is greater than or equal to 1). Therefore, in FIG. 3B and 3D modules are designated as M_i,j. Of course, the rows and columns can change places depending on the orientation of the grid.

It should be noted that the grille module, which is not needed to generate the required airflow, can be detached in order to avoid deflecting the generated airflow. In the figures, the detached modules M are shown, for example, in white.

In the second embodiment shown in FIG. 4A and 4B, air duct 400 is in the form of a tube having a cylindrical shape, preferably circular in cross section, and defining a channel 401 open at its two ends 402, 403. The tube includes at least one wall 404, which is formed by an array of thermoelectric modules. In this embodiment, the module-bearing wall 404 is not necessarily flat, and therefore corresponds to the cross section of the tube. Similar to the first embodiment, as can be seen in section B-B of the tube in FIG. 4B, one side of each module is oriented towards the inside of the tube and the other side of each module is oriented outward of the tube. Referring to FIG. 2A and 2B, each module M is therefore made with three concentric layers, respectively formed, in order from the inside out, from the first plate 31, the structure 30, and the second plate 32. Therefore, the tube can be obtained by assembling a plurality of thermoelectric modules placed end to end from one end of the tube to the other. The support element 405 connects one module to another and serves as a support for the grid. The created air flow F100 passes through the channel 401 formed by the tube according to the principle of natural convection, from the module with the coldest inner side to the module with the hottest inner side. Likewise, valves 407 may be provided to partially or completely block each opening of the tube. Likewise, each thermoelectric tube module can be individually addressed by the UC control unit. In FIG. 4A, each module is identified by a different rank along said tube and denoted as M_k, where k is from 1 to n. One or more intermediate openings may be provided through the side wall 404 of the tube, for example at the level of each carrier 405, to create other air flows.

The same electrical cabinet 1 may include a plurality of tubes of this type, for example arranged in parallel or in a number of configurations in order to adapt to the internal architecture of the cabinet. The tubes can be attached to supports and guides 7 of electrical devices 6.

In operation, the individualized control of each thermoelectric module allows for various applications.

The first application concerns the creation of air flow in the duct by creating a temperature gradient on the inside of the duct. The gradient is created by appropriately controlling the modules of the grating 20, which are present in the subset aligned with the direction of the generated airflow, by adapting the temperature of that side A of the matrix that corresponds to the inner side. The air flow is actually created by natural convection in the direction from cold to hot.

Accordingly, considering the first embodiment described above, an aligned subset along column j containing n modules, and a generated airflow that corresponds to an increasing rank of i:

– the module with coordinates M_1,j is controlled by the control unit UC so as to bring its inner side to the first temperature TA_1,j;

– the module with coordinates M_2,j is controlled by the control unit UC so as to bring its inner side to the second temperature TA_2,j, which is higher than the first temperature TA_1,j;

– the module with coordinates M_i,j is controlled by the control unit UC so as to bring its inner side to a temperature TA_i,j that exceeds the temperature TA_i–1,j;

– the module with coordinates M_n,j is controlled by the control unit UC so as to bring its inner side to a temperature TA_n,j higher than the temperature TA_n–1,j.

This principle is illustrated in Fig. 3A and 3B by generating airflow F10 by means of a vertically aligned subset of modules along the second column of the grid (j=2). The same principle can be applied along the array row as shown in FIG. 3C and 3D through the use of side duct openings. In FIG. 3C and 3D, flow F20 is created by an aligned subset of modules along the third row of grid 20 (i=3). This principle would be exactly the same for creating F30 airflow or even F100 airflow inside the tube.

In this case, the principle of operation can be as follows:

– the UC control unit continuously receives temperature data from the temperature sensors T;

– depending on the received temperature data, the UC control unit determines whether or not the creation of one or more air flows is required, and if so, determines the direction of each air flow to be created and its intensity;

– after the characteristics of each airflow to be created, the control unit UC determines the modules M of the array 20 participating in the creation of the airflow, and determines the temperature assigned to each module to create a temperature gradient sufficient to create the airflow;

– the UC control unit sends an individualized temperature command to each thermoelectric module, forcing it to acquire the required temperature;

- due to natural convection, an air flow is created between the selected lattice modules; openings of the system which are suitable for the passage of the generated air flow are commanded to open to allow the air flow to circulate;

– at any time, the UC control unit can interrupt the airflow by turning off one or more selected thermoelectric modules and issuing a new sequence of commands to create a new airflow.

Of course, the temperature gradient created must be sufficient and appropriate for the airflow generated. The UC control unit may use an algorithm configured to determine the temperature assigned to each thermoelectric module, considering the direction and importance of the generated airflow and its intensity.

In addition, it should be understood that two adjacent modules in an aligned subset may be commanded to be given the same temperature.

The second application is related to obtaining localized cooling or heating in the electrical cabinet. To this end, depending on the received temperature data, the control unit may instruct one or more thermoelectric grid modules to lower the temperature (in the case of the presence of a "hot spot") or increase the temperature (for example, to remove moisture present).

The air duct may include more than two openings in order to be able to create different types of air currents. Each opening can be controlled by a valve that can be commanded to open or close.

In accordance with one particular aspect of the invention, in order to influence the airflow rate, each valve may be commanded to adjust the size of its respective opening. Therefore, it may be possible to create an acceleration of the airflow by controlling the size of the openings.

Obviously, the solution according to the invention has numerous advantages, including:

– a solution that is easy to implement;

– a solution that is reliable and not very prone to failures, in contrast to classical ventilation solutions;

– a solution that requires limited maintenance, while thermoelectric modules do not have mechanical parts and are particularly easy to replace;

– a solution that provides the creation of air flows in multiple directions, on command, without intervention.

Claims (17)

1. A system for controlling temperature and for creating an air flow in an electrical enclosure, characterized in that it includes: an air duct (40, 400) containing at least a first opening, a second opening and a channel (41, 401) located between said first opening and said second opening in order to enable said air flow to pass between the two openings, lattice (20) from a set of independent thermoelectric modules (M), wherein said array contains at least one aligned subset of the plurality of thermoelectric modules, which is located in a direction called the main direction, and each thermoelectric array module has two opposite sides and is addressed in an individualized manner to create a Peltier effect between its two sides, wherein said aligned subset of the plurality of thermoelectric modules (M) is oriented along said duct, each array module having one side inside said duct and one side outside said duct, a control unit (UC) configured to control each grid thermoelectric module in an individualized manner. 2. System according to claim 1, characterized in that all thermoelectric modules (M) are identical. 3. The system according to claim 1 or 2, characterized in that the array (20) of modules includes a plurality of thermoelectric modules organized in a plurality of rows and at least one column, each row of thermoelectric modules being given a rank i, where i is from 1 to n, where n is greater than or equal to 2, and each column of thermoelectric modules is given a rank j, where j is from 1 to m, and m is greater than or equal to 1. 4. The system according to claim 3, characterized in that the control unit (UC) is configured to address each array module by its i, j coordinates in the array. 5. The system according to claim 4, characterized in that the thermoelectric modules are placed in the grid in such a way as to form a quasi-continuous surface. 6. System according to claim 5, characterized in that said surface is flat. 7. System according to claim 1 or 2, characterized in that the air duct (400) is formed by a tube having at least one wall delimiting said channel, and in that said tube wall forms a support for said grid. 8. The system according to any one of paragraphs. 1-7, characterized in that the control unit (UC) includes a module for determining those thermoelectric modules that should be controlled by temperature depending on the direction and importance of the air flow created in the duct. 9. The system according to any one of paragraphs. 1-8, characterized in that the control unit (UC) includes a module for determining the temperature of each thermoelectric module, taking into account the orientation of the air flow and the intensity of the generated air flow. 10. System according to claim 1, characterized in that the duct (40) includes at least one wall formed by the wall of the electrical enclosure. 11. The system according to any one of paragraphs. 1-10, characterized in that it includes a valve that can be commanded to partially or completely block each hole. 12. Electrical enclosure, including a plurality of walls that define an internal volume, designed to receive electrical or electronic devices, characterized in that it includes a system for temperature control and for creating an air flow, characterized in any one of paragraphs. 1–11.

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