Device for converting heat energy into electrical current

Abstract

The invention relates to a device for converting heat energy into electric current, wherein a temperature difference is converted into electric current by means of a Peltier element. The device includes: • at least one cold storage chamber (1) enclosed by walls (3), • at least one heating chamber (2) open to the outside towards a heating area (5), wherein the heating and cooling chambers adjoin each other by means of one of these walls (3) so that this wall of the cooling chamber also forms a wall of the heating chamber, and wherein this wall comprises a Peltier element, and • Pipes (8) for a liquid or gaseous cooling medium with an inflow into the cooling chambers (1), and • a bell (4) which surrounds all cooling chambers (1) and heating chambers (2) and separates the heating area (5) of the device from the outside environment (6). Also described are sets consisting of a device with a battery and / or with a lens for sunlight, as well as the use of the device in living spaces and a method that makes use of the device.

Description

[0001] The invention relates to the conversion of thermal energy into electrical current, whereby a temperature difference is converted into electrical current by means of a Peltier element.

[0002] Peltier elements are well known. They are electrothermal converters that, based on the Peltier effect, generate a temperature difference when a current flows through them, or (conversely and relevant to the invention) a current flow when a temperature difference occurs (Seebeck effect).

[0003] Peltier elements are used, for example, in camping coolers.

[0004] The object of the invention is to provide a device for generating electricity that operates after a short warm-up phase. It should require as little effort as possible during operation. Furthermore, it should also offer the possibility of mobile use.

[0005] The object of the invention is achieved by the features of the independent main claims. Preferred embodiments are clarified by the dependent subclaims.

[0006] The invention relates to a device for converting thermal energy into electrical current, comprising • at least one cooling chamber enclosed by walls, • at least one heating chamber open to the outside to a heating area, wherein the heating and cooling chambers are adjacent to each other by means of one of these walls, so that this wall of the cooling chamber also forms a wall of the heating chamber, and wherein this wall includes a Peltier element, and • Pipes for a liquid or gaseous cooling medium with an inflow into the cooling chambers, and • a bell (preferably removable) which surrounds all cooling chambers and heating chambers and separates the (one common) heating area of ​​the device from the outside environment.

[0007] The core of the invention is that a wall comprising a Peltier element separates both a cold chamber and a heat chamber. It thus serves as both the wall of the cold chamber and the wall of the heat chamber. This also includes walls that separate the cold chamber from the heating zone (because, according to the invention, the heat chambers are open to the heating zone).

[0008] It is expedient for the number of cooling and heating chambers in the device according to the invention to be the same, particularly preferably 3 or 5 or twice as many, ie 6 or 10. Thus, there is always a pair of cooling chamber and heating chamber, with the different walls separating different cooling and heating chambers from each other.

[0009] The Peltier element is usually made of aluminum oxide ceramic. For cooling:

[0010] Each closed cooling chamber has at least one inlet for the cooling medium to be cooled.

[0011] It's also sensible to have a drain from the cooling chamber for the cooling medium (at least in the case of a liquid cooling medium that doesn't evaporate). Gaseous cooling media or liquid cooling media that completely evaporate, such as liquid nitrogen, can escape from the cooling chamber through cracks and do not require a drain. Possible cooling media include water, cooling spray, gaseous refrigerants such as those used in refrigerators, organic cooling media such as ethylene glycol, and others.

[0012] Preferably, each wall of the enclosed cooling chambers borders on a heating chamber or at least on the heating area (with the obvious exception of the walls that reach the floor). However, it is also possible to position the device on spacers or stilts so that the heating area is also formed below, which is shielded from the outside environment by the bell.

[0013] The "bell" in the sense of the invention can be black or transparent, for example. It is preferably removable, which offers advantages for maintenance, but can also be permanently attached to the floor or a floor plate above which the cooling and heating chambers are arranged.

[0014] In any case, it has a certain degree of thermal insulation, so that the heating zone can reasonably reach a temperature above room temperature. In any case, according to the invention, the temperature in the heating zone (and thus also in the heating chambers open to the heating zone) must be higher than in the cooling chambers, in particular by at least 20°C.

[0015] Due to this temperature difference between the cooling and heating chambers, electricity is generated on the wall (or walls) that define both a heating chamber and a cooling chamber by means of the wall's Peltier element. Electricity is also evidently generated on the walls that separate the cooling chamber from the heating area (as, for example, in the examples shown in Example 1 / Fig. 2 shown wall surfaces facing outwards).

[0016] The subject matter also includes a set for converting thermal energy into electrical current, comprising the device according to the invention, with a battery connected to the Peltier elements, and / or with a lens for directing sunlight onto the device. In a preferred embodiment with electric heating, mentioned below, the battery would also be usefully connected to this electric heating.

[0017] The invention also relates to a method for converting thermal energy into electrical current, comprising the steps: a) heating the heating area of ​​the device according to the invention to a temperature difference between cooling chambers and heating chambers of at least 20K (the heating chambers have the higher temperature and the cold chambers the lower), for the initial charging of a battery connected to the device, and b) continuous cooling of the enclosed cooling chambers by means of a liquid or gaseous cooling medium.

[0018] Embodiments of the method thus clearly also relate to the set according to the invention with a battery or an embodiment of the device with a battery.

[0019] Finally, the subject matter also includes the use of the device (or set) according to the invention for integration into a living space wall of a building, wherein the cooling medium for the cooling chambers is guided past the building's floor slab for cooling. Experience has shown that the building's floor slab has lower temperatures than the ambient air and can therefore serve to cool the cooling medium, so that it can be guided from there into the cooling chambers of the device according to the invention. In particular, the subject matter also includes the use in the method according to the invention.

[0020] Finally, embodiments of the device according to the invention also relate to the inventive objects set, method and use.

[0021] The invention advantageously allows mobile power generation with constant cooling, for example by means of a mobile cooling spray.

[0022] The device can use the sun as a starting point for heating the heating area and the heat chambers open to it, for example, to charge a battery and then enable extended operation even without sunlight. All that is required is continuous or intermittent cooling of the cooling chambers. The effort required to maintain continuous, long-term operation is thus minimal.

[0023] The design, in which the closed cooling chamber shares a wall with a heating chamber, is insulated by a bell jar, ensures continued operation even in the dark, for example, overnight. If sunlight is still unavailable, it is possible to heat the system using an electric heater within the heating area, as described in a preferred embodiment later in this document.

[0024] This inventive structure with a “divided wall” also allows for multi-story construction. Preferred embodiments

[0025] In a preferred embodiment of the invention, the line for the cooling medium leads from a refrigerator or freezer into the cooling chambers. The device preferably also includes a battery (DC) and a 220V inverter for operating a standard household AC refrigerator, with this battery connected to the Peltier elements of the device so that the battery is charged.

[0026] It is preferred in the process if the heating chambers (after heating in step a) reach a temperature of 50°C ±5°C and the temperature in the cooling chambers is thus 30°C ±5°C. This temperature range has proven optimal for a balanced balance between energy input (solar or electricity) and energy output (cooling and energy generation).

[0027] In step b), the cooling medium is preferably introduced into the respective cooling chambers from above. This advantageously results in a more uniform cooling effect along the vertical walls and the upper wall.

[0028] Preferably, a heat sensor is located in the heating area of ​​the device according to the invention, and a cold sensor is located in each of the cold chambers. This advantageously allows monitoring of the target temperature difference of at least 20K.

[0029] In a preferred embodiment of the invention, the device comprises: • at least three of the cooling chambers, each having the shape of a three-sided isosceles prism and touch each other at their respective edges between the same legs and form an axis of symmetry there and where they are distributed symmetrically over the 360° around the axis of symmetry and form spaces (i.e. with 3 cooling chambers, they are offset by 120° each; with 5 cooling chambers they would be offset by 360° / 5 etc.), and • at least three of the open heat chambers extending into these spaces, whereby these open heat chambers are also three-sided isosceles prisms (i.e. have this shape; whereby, since the heat chambers are open, only the two isosceles surfaces of the three side surfaces are present - with reference to the lower representation of an isosceles prism, the wall is missing on the surface c*h, so to speak), so that these cooling and heating chambers form a first floor of the device, and where the walls (of the cooling chambers) include Peltier elements on all three sides of the isosceles triangles (these are the areas a*h, b*h and c*h in the lower illustration of this prism shape) and have cooling fins on both sides of the walls (wall sides).

[0030] Since the open heating chambers extend into the gaps, the heating chambers are also distributed symmetrically across the 360°, so that a cooling chamber and a heating chamber always alternate on this first floor. "First floor" is the first floor counted from the bottom, i.e., as seen from the floor or a floor slab.

[0031] The heating chambers therefore only have “cooling chamber walls”.

[0032] A three-sided isosceles prism has the Fig. 5 shown geometric shape: The axis of symmetry mentioned here is the one between point C on one base (ABC) and the point on the opposite base.

[0033] Preferably, all cooling chambers have the same shape, and consequently, the heating chambers also have the same shape. Regarding the walls, this means (in a design with exactly three cooling chambers on one floor, as in Fig. 4) that there are nine (vertical) walls on this floor, six of which directly connect the cooling chambers and heating chambers, and three of which separate the cooling chambers from the heating area. According to the invention, each of these walls encloses the Peltier element.

[0034] It is noticeable that in this (symmetrically distributed) arrangement along a symmetry axis, the number of cooling chambers and the number of heating chambers on each floor are the same.

[0035] Cooling fins are devices for improving the transfer of heat energy from or to the Peltier elements in the walls. The cooling fins extend from a cooling chamber into the heating zone on one side and into the cooling chamber on the other.

[0036] Most preferably, all walls of the cooling chambers comprise Peltier elements with cooling fins on both sides of the wall (except for the bottom wall if a cooling chamber is located directly on the floor without spacers).

[0037] In a particularly preferred variant of this embodiment with at least three cooling chambers and at least three heating chambers, the side walls forming the isosceles prism are glued together; in particular, all walls of the device according to the invention can be glued together.

[0038] In a preferred embodiment of the invention, the walls have such cooling fins covering at least 75% of their respective surface area (on both sides of the wall). In any case, the cooling fins cover at least the same area of ​​the wall as that formed by the Peltier element.

[0039] In a preferred variant of the embodiment with at least three cooling chambers and at least the heating chambers in a first floor, at least one further floor is included in the same structure as the first floor and this further floor is located above the first floor, wherein the first and each further (following upwards) floor are offset from each other about the axis of symmetry such that each cooling chamber is delimited from above by a heating chamber and vice versa.

[0040] This means that this additional floor (more than two floors are also possible) also includes at least three cooling chambers and at least three heating chambers, etc. It makes sense then that the triangular top and bottom of all cooling chambers of the additional floor (located above) also form walls according to the invention with a Peltier element.

[0041] Each floor is offset from the adjacent floor by 360° / (2x), where x is the number of cooling chambers on the floor. This means that with three cooling chambers per floor, there are three cooling chambers and three heating chambers on a floor, for a total of six chambers. The adjacent floor is offset by 360° / 6 (or more precisely, rotated around the axis of symmetry), i.e., by 60°. This means that a heating chamber is located above a cooling chamber, and vice versa.

[0042] The advantage of this multi-story construction is better efficiency and longer operation even without solar radiation or electrical heating.

[0043] The lowest level (first level) is ideally defined by a base plate onto which the bell according to the invention can be placed. However, as already mentioned above, it is also possible to position the device on spacers or stilts, thus creating a heating zone below that is shielded from the outside environment by the bell.

[0044] In another preferred embodiment, 70% (preferably 75-85%) of the wall surface is made up of the Peltier element; this is particularly the case for all walls. The remaining wall surface can be covered with aluminum foil for better insulation. Heat transfer through the wall should only occur at the locations of the Peltier element.

[0045] In a likewise preferred variant of the above-mentioned embodiment of the invention with an axis of symmetry, a riser pipe is provided in the region of this axis of symmetry, in which the pipes for the liquid or gaseous coolant are arranged.

[0046] There they lead from floor to floor (if there are several floors); in any case, the lines can be easily led from there into all cooling chambers, since each cooling chamber (in this embodiment) touches each other at its respective edge between the equal legs (of the isosceles prism).

[0047] The "riser" is a pipe with the axis of symmetry at its center, adjacent to each cooling chamber. This arrangement is best suited for space-saving storage of the cooling medium lines and electrical cables that must be routed into the cooling chambers (or, more accurately, to the Peltier elements).

[0048] In a preferred embodiment of the invention, cooling fins are arranged on both sides of the walls. These are preferably made of a material selected from aluminum and copper.

[0049] In a preferred variant of the design with at least three cooling chambers and at least three heating chambers, an electric heater extends between the heating area and the heating chamber in at least one heating chamber on the first (lowest) floor; better in each heating chamber on the first floor.

[0050] This is particularly preferably a rolled heating foil.

[0051] The advantage is that this electric heater can be used both for the initial heating (with the bell closed) and for subsequent heating of the heating area, allowing the device to be used in the dark. Sunlight is no longer required.

[0052] In another preferred embodiment of the invention, the bell is made of glass or PVC and is covered with a reflective foil covering at least 35% of its surface area (especially 35-50%). The advantage of this transparent design is that sunlight can penetrate and is reflected by the reflective foil inside the bell. This is suitable for heating the heating area of ​​the device according to the invention in the sun.

[0053] The foil is arranged in such a way that sunlight falling diagonally from above onto the bell is reflected from the inside of the bell behind the cooling and heating chambers, so that more of the sun's heat energy is available inside the bell in the heating area.

[0054] It is also preferred if the Peltier element is square and has a size of 4cm x 4cm to 8cm x 8cm.

[0055] In a preferred variant of the design with at least three cooling chambers and at least three heating chambers, the device has exactly three heating chambers and three cooling chambers per floor. Advantageously, one cooling chamber has warm outer surfaces (except for the cooling chamber on the lowest floor). This variant is particularly suitable for saving space while maintaining high efficiency and a simple construction. The design is also not too small to be manufactured by hand.

[0056] In a preferred embodiment of the process according to the invention, the heating in step a) is carried out by means of - exposure of the device to solar radiation, and / or - Heating the heating area using an electric heater. Both are also possible.

[0057] The electric heater is at best a rolled heating foil, as described above.

[0058] The advantage is that the initial heating of the device (with the bell closed) does not have to be done by sunlight, but can also be done by the electric heater.

[0059] The device in this version also works without sunlight. Fig. 1 shows an excerpt of a cooling chamber of a preferred embodiment from embodiment 1. Each of the walls shown can form a wall of an adjacent heating chamber. Fig. 2 shows the two-story design of the device according to embodiment 1 (the bell is not shown). Fig. 3 indicates in the same figure the cooling chambers and the heating chambers as well as the centrally located axis of symmetry. Fig. Figure 4 shows a top view of this two-story design, highlighting the bell that separates and thermally insulates the heating zone (inside the device according to the invention) from the outside environment. Visible are the upper level with its (vertical) walls, as well as the (horizontal) upper wall surfaces of the cooling chambers of the lower level (which also have cooling fins, but these are not shown). It should be noted that there is a common heating zone of the device, i.e., the Fig. 4 visible prisms do not border on the bell 4, but leave a gap so that a common heating area is formed inside the bell.

[0060] It is advisable to combine the different embodiments with each other, unless otherwise stated.

[0061] The invention will be explained in more detail below using several preferred embodiments. These are not intended to limit the invention. ExamplesExample 1

[0062] The embodiment shown in the figures according to Example 1 is a two-story device. The bell 4 is, except for Fig. 4, not shown, and serves to be placed over the cooling and heating chambers (1,2) so that the heating area 5 is separated and insulated from the external environment 6 of the device.

[0063] Each floor has three cooling chambers 1 and three heating chambers 2. All six are distributed symmetrically around an axis of symmetry 9. In the area of ​​the axis of symmetry 9 there is a riser 10 in which the lines 8 for the cooling medium and, sensibly, the electrical cables leading to the Peltier elements are stored. The symmetrical arrangement of the cooling and heating chambers on one floor is offset by exactly 360° / 6, i.e., by 60°, around the axis of symmetry on the other floor. Each of the existing walls (all cooling and all heating chambers) has a Peltier element, with cooling fins 7 attached to the surface of the Peltier element both inside and outside (i.e., on both sides of the wall) - the only exception here is the lowest wall of the lowest floor, which is in contact with the base plate.

[0064] The cooling chambers in Fig. 1. There, the Peltier elements are located below the cooling fins 7. Reference symbol 1 cooling chamber (closed) 2 heating chambers (open to the heating area) 3 walls, including Peltier element 4 bell 5 Heating area 6 Outdoor environment (outside the cooling and heating chambers enclosed by the bell) 7 cooling fins 8 lines (for cooling medium with inflow into the cooling chambers) 9 axis of symmetry 10 Riser pipe (for cooling medium pipes)

Claims

[1] Device for converting thermal energy into electrical current, comprising • at least one cooling chamber (1) enclosed by walls (3), • at least one heating chamber (2) open to the outside to a heating area (5), wherein the heating and cooling chambers are adjacent to one another by means of one of these walls (3), so that this wall of the cooling chamber also forms a wall of the heating chamber, and wherein this wall comprises a Peltier element, and • Lines (8) for a liquid or gaseous cooling medium with an inflow into the cooling chambers (1), and • a bell (4) which surrounds all the cooling chambers (1) and heating chambers (2) and separates the heating area (5) of the device from the outside environment (6). [2] Device according to claim 1, comprising • at least three of the cooling chambers (1), each having the shape of a three-sided isosceles prism and touch each other at their respective edges between the same legs and form an axis of symmetry (9) and where they are distributed symmetrically over the 360° of the axis of symmetry and form spaces, and • at least three of the open heat chambers (2) extending into the spaces, and these open heat chambers are also three-sided isosceles prisms, so that these cooling and heating chambers form a first floor of the device, and wherein the walls comprise Peltier elements on all three sides of the isosceles triangles and have cooling fins (7) on both wall sides. [3] Device according to claim 2, wherein at least one further floor is included in the same structure as the first floor and is located above the first floor, wherein the first and each further floor are offset from each other about the axis of symmetry (9) such that each cooling chamber (1) is delimited from above by a heating chamber (2) and vice versa. [4] Device according to one of claims 2 or 3, wherein the wall (3) is formed by the Peltier element to 70% of its area. [5] Device according to one of claims 2 to 4, wherein in the region of the axis of symmetry (9) there is a riser pipe in which the pipes (8) for the liquid or gaseous coolant are arranged. [6] Device according to one of claims 2 to 5, wherein the cooling fins (7) are made of a material selected from aluminum and copper. [7] Device according to claim 6, wherein at least in each heating chamber (2) of the lowest floor an electric heater extends between the heating area (5) and the heating chamber. [8] Device according to one of claims 1 to 7, wherein the bell (4) is made of glass or PVC and is covered with a reflective foil for at least 35% of its surface. [9] Device according to one of claims 1 to 8, wherein the Peltier element is square in size 4cm x 4cm or 8cm x 8cm. [10] Device according to one of claims 2 to 8 with three heating chambers (2) and three cooling chambers (1) per floor. [11] Set for converting thermal energy into electrical current, comprising a device according to any one of claims 1 to 10, with a battery connected to the Peltier elements and / or with a lens for directing sunlight onto the device. [12] Use of a device according to one of claims 1 to 10 for integration into a living space wall of a building, wherein the cooling medium for the cooling chambers (1) is guided past the building floor slab for cooling. [13] Process for converting thermal energy into electrical current comprising the steps: a) heating the heating area (5) of a device according to one of claims 1 to 10 to a temperature difference between cooling chambers (1) and heating chambers (2) of at least 20K, for the initial charging of a battery connected to the device, and b) continuous cooling of the enclosed cooling chambers by means of a liquid or gaseous cooling medium. [14] Method according to claim 13, wherein the heating in step a) is carried out by means of - exposure of the device to solar radiation, or - Heating the heating area using an electric heater.

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