WO2011060951A2

WO2011060951A2 - Power generating device

Info

Publication number: WO2011060951A2
Application number: PCT/EP2010/007047
Authority: WO
Inventors: Franz-Josef Struffert; Josef REISLÖHNER; Wilhelm Heiss
Original assignee: Getes Geothermie Ag
Priority date: 2009-11-20
Filing date: 2010-11-19
Publication date: 2011-05-26
Also published as: DE202009015903U1; WO2011060951A3

Abstract

The invention relates to a power generating device, comprising at least one thermocouple, which has a first surface for absorbing heat and a second surface for dissipating heat and is designed to generate electric energy based on a temperature difference between the first and second surfaces, at least one heat supply region, which supplies heat to the first surface of the at least one thermocouple, and at least one heat dissipating region, which dissipates heat from the second surface of the at least one thermocouple.

Description

POWER GENERATION DEVICE

FIELD OF THE INVENTION

The present invention generally relates to power generation devices, and more particularly to a power generation device including at least one thermocouple and a heat transport device and a photovoltaic device having such a power generation device.

BACKGROUND OF THE INVENTION

In known systems for the heat supply, such as geothermal plants, district heating or other facilities that are provided with heat cycles, heat in a medium, usually water, transported and delivered to a designated location, for example. By means of a heat exchanger. The cooled medium is then passed back to a heat source and again returned to the circulation in a heated state. Since, in general, the actual heat loss is not predictable, such heat supply systems generally have some amount of unused residual heat.

The object of the present invention is to improve the energy efficiency of existing plants in which heat is transported or generated. SUMMARY OF THE INVENTION

According to a first aspect, the present invention provides a power generation apparatus comprising: at least one thermocouple having a first surface for receiving heat and a second surface for emitting heat and being configured due to a temperature difference between the first and second surfaces to generate electrical energy; at least one heat supply area supplying heat to the first surface of the at least one thermocouple; and at least one heat dissipation area that dissipates heat from the second surface of the at least one thermocouple. According to a second aspect, the present invention provides a heat transport device, in particular a geothermal, district heating or cooling system, comprising a power generation device according to the first aspect, wherein the heat transport device comprises a heat-carrying transport circuit with a heat transport medium, the transport circuit at least a flow and a return wherein the heat transport medium in the flow has a higher temperature than in the return, the flow is at least partially disposed in the heat supply region of the power generation device, and the return is at least partially disposed in the heat dissipation region of the power generation device.

According to a third aspect, the present invention provides a photovoltaic device for generating electricity, comprising a power generating device according to the first aspect, wherein the photovoltaic device has at least one photovoltaic element having a front side for collecting solar rays and a back side; the back of the at least one photovoltaic element is at least partially disposed in the heat supply region for the at least one thermocouple; and the heat removal area is at least partially traversed by a fluid, in particular air or water. Further aspects and features of the present invention will become apparent from the dependent claims, the accompanying drawings and the following description of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

Fig. 1 illustrates an embodiment of a power generating device in accordance with the present invention;

Fig. 2 illustrates a geothermal plant and a district heating network supplied with heat from the geothermal plant; Fig. 3 shows the geothermal system and the district heating network according to Fig.2 with therein power generating devices of Figure 1 for residual heat utilization. and

FIG. 4 illustrates a photovoltaic device with a power generating device of FIG. 1. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Fig. 1, an embodiment in accordance with the present invention is illustrated. Before a detailed description follows first general explanations to the embodiments and their advantages. Thermoelectric elements or thermocouples are generally known, which are formed, for example, from two different metals or, in the case of thermoelectric generators, also from semiconductor materials. The thermocouples have a so-called "warm" side and a "cold" side. Due to a temperature difference between the hot and the cold side, the thermocouple can generate electricity due to the Seebeck effect. If the thermocouple consists of a semiconductor material, then it is called after the Peltier effect Peltier element. The Peltier effect is just the reverse of the Seebeck effect, that is, applying a current makes the Peltier elements on one side warm and cold on the other.

Thermocouples as such are primarily used as temperature sensors. The generated current or voltage is converted into a corresponding temperature signal. In contrast, thermocouples in the form of Peltier elements are used primarily as cooling elements. Nowadays thermocouples are used millions of times as cooling elements of the smallest degree for electronic components. State of research is to develop so-called. Thermoelectric generators to improve the mode of action.

The inventors have now recognized that thermocouples, in particular in the Form of thermoelectric generators, generally to improve energy efficiency, especially in geothermal, district heating, cooling and photovoltaic systems use or use. The thermocouples are used or used so that they use residual heat and / or unneeded heat to generate electricity.

In this case, thermocouples can be used in geothermal plants, in particular in systems of hydrothermal deep geothermal energy, connected or independently in systems of district heating, cooling systems, cooling circuits of any kind, for residual heat and in combination with photovoltaic elements / plates / components. Due to the mode of action of the thermocouples existing heat is better and more fully used in such systems, thereby improving the efficiency of the thermal systems. Through better utilization, it is possible to save CO2 emissions and, for example, to achieve a direct improvement in the electrical yield in photovoltaic systems.

A thermocouple consists in some embodiments of three main components. A central region, for example with a semiconductor element or an element with suitable materials, which cause the Seebeck effect, such as ΒΪ2Τβ3, PbTe, SiGe, BiSb or FeSi _2, and two surface regions sandwiching the central region. The surface regions can also be formed as separate elements, for example as plates or the like. The thermocouple is also designed plate-like in some embodiments, and the cold or warm side is located respectively at the top and bottom of the thermocouple. On the warm side, heat is then applied to the thermocouple in some embodiments, while heat is dissipated on the cold side. If, for example, the heat flows via the plates over the hot side through the thermocouple to the cold side, a current is generated in the middle region. eg in the semiconductor material. Accordingly, in some embodiments, a power generating device includes at least one thermocouple for utilizing Heat or residual heat generated in a district heating system, refrigeration systems, cooling circuits of any kind, or photovoltaic elements / plates / components.

The thermocouple has a first surface for receiving heat and a second surface for dissipating heat. As mentioned, the surface can be, for example, the surface of the semiconductor material or be formed by a plate, coating or other thermally conductive element, which is in thermal contact with the due to temperature difference generating element. The thermocouple is configured to generate electrical energy due to the temperature difference between the first and second surfaces.

In order to transport the heat to the first surface, that is to say the warm side, of the thermocouple, the power generation device has a heat supply region, which supplies heat to the first surface of the at least one thermocouple. And in order to produce the temperature difference necessary for power generation, the power generation device has a heat dissipation area that absorbs heat from the second surface, i. the cold side, the at least one thermocouple dissipates.

Due to this configuration, the power generating device can be used in equipment as described above or other technical devices in which there is a plant-related heat supply and heat dissipation. Thus, the power generation device in any technical (thermal) systems or heat transport circuits existing residual heat to use for power generation. Technically known thermocouples usually have relatively small dimensions, for example in the square centimeter range. Thus, in some embodiments, the power generation device includes an array having a plurality of thermocouples, wherein the thermocouples are electrically connected in series and thereby form a thermoelectric generator. The thermocouples are connected in series between the cold and the warm side in order to generate the highest possible voltage. Such arrays can have hundreds, thousands or even 100,000 or more thermocouples.

In addition, the thermocouples can be adapted according to the requirements, in particular the temperatures prevailing on the cold and hot side, and to the corresponding temperature difference, in order to ensure optimum generation of electrical energy (current or voltage).

In some embodiments, at least one thermocouple or at least one power generation device is used with at least one thermocouple in a plant, such as. Geothermal, district heating or cooling system or the like or used for Wärmenutzug in photovoltaic systems.

In some embodiments, according to a heat transport device, in particular a geothermal, district heating or cooling system, at least one power generating device as described above. The heat transport device has, for example, a heat-carrying transport circuit with a heat transport medium. The heat transport medium may be a fluid, such as, for example, air or water or any other heat transfer medium which is suitable to transport heat.

The transport circuit has at least one flow and one return, wherein the heat transport medium in the flow has a higher temperature than in the return. The transport cycle can be an open or closed circuit. In some embodiments, the flow and the return are, for example, so separated that they are in no communicating connection with each other, while in other embodiments, the flow and return are in communicating connection.

The flow is at least partially disposed in the heat supply region of the power generating device and thus can deliver heat to the first surface of the at least one thermocouple, whether by direct or indirect heat-conducting contact or by thermal radiation.

The return is at least partially disposed in the heat dissipation region of the power generating device and accordingly receives heat from the second surface of the thermocouple, which is discharged, for example, via direct or indirect heat conduction or by heat radiation from the second surface.

By the supply of heat from the flow to the first surface of the at least one thermocouple and the heat removal from the second surface via the return, a corresponding temperature difference between the first surface of the thermocouple and the second surface of the thermocouple, due to which the at least one thermocouple electrical energy (current ).

The flow of the heat transport device and the return of the heat transport device are in some embodiments, not necessarily equal to the flow or return of an entire system, eg. A geothermal or district heating system or a cooling system. The supply and return refer here only to the part of the transport system of the heat to the power supply device, i. to the at least one thermocouple, leads or dissipates. In some embodiments, at least one thermocouple or at least one power supply device as described above is used in a photovoltaic device to generate power.

In this case, the photovoltaic device has at least one power generating device with at least one thermocouple, as described above, and at least one photovoltaic element.

The photovoltaic element has a front for catching sun rays and a back side opposite to the front side. The rear side of the at least one photovoltaic element is at least partially in the heat supply region for the at least one thermocouple arranged. Photovoltaic elements heat up strongly due to the sun's rays, which not only leads to a lower efficiency of the photovoltaic element itself, but also leaves a corresponding amount of energy unused. In particular, at the back of the photovoltaic elements creates a lot of heat, which can be used by the arrangement of thermocouples in this area to generate electricity.

The heat dissipation region of the at least one thermocouple is at least partially traversed by a fluid, such as, for example, air or water. In some embodiments, for example, passing air flows along the second surface of the thermocouple and thereby cools it on the second surface. By cooling on the one hand and the heat supply on the other hand, a corresponding temperature difference between the first surface and the second surface is produced, whereby the thermocouple can generate electrical energy. In embodiments in which there is a (direct) heat conduction contact between the thermocouple and the photovoltaic element, not only the heat generated at the back of the photovoltaic element can be used to generate electricity, but the thermocouple additionally cools the corresponding photovoltaic element by the heat dissipation, whereby the efficiency of the photovoltaic element, which is temperature dependent, is also increased.

Returning to Fig. 1, there is shown an embodiment of a power generating device 1 in accordance with the present invention. The power generation device has a thermocouple 2, which is arranged between a heat supply region 6 and a heat removal region 7.

The thermocouple 2 has a rectangular, plate-like shape and is formed of a semiconductor material 3 sandwiched between two plates 4 and 5. In this case, the upper plate 4 forms a first surface on which heat is supplied via the heat supply region 6, while the lower plate 5 forms a second surface on the heat to the heat removal region 7 is delivered. Consequently, with appropriate heat supply and heat dissipation, a temperature difference between the upper plate 4 and the lower plate 5, which leads to a power generation in the semiconductor material 2.

As already mentioned, in some embodiments, the power generation device has a plurality of thermocouples 2, which are connected in series and, for example, are arranged in an array. In such embodiments, the upper 4 and lower plates 5 may be continuous. In other embodiments, however, each thermocouple has a single plate or mixed forms are realized in which, for example, several thermocouples are combined to form a module and these modules each having an upper and a lower plate.

The power supply device is correspondingly easy to use in cooling systems and cooling circuits of any kind and the residual heat.

For this purpose, the power supply device must be used only in the cooling system or the cooling circuit or the like, that heat is supplied to the heat supply region 6 and heat is dissipated in the heat dissipation region 7.

This is shown in Fig. 1 by corresponding arrows 8 and 9. The upper arrow 8, which points in the direction of the heat supply region 6, stands for a heat supply, for example from a cooling circuit originating from a geothermal heat source or from any other suitable (residual heat source Water pipes or by another suitable heat transfer line in the heat supply area 6 and there, for example, by direct or indirect (eg., By heat exchanger) thermally conductive contact to the upper plate 4 or by heat radiation to the upper plate 4 is discharged the upper plate 4 ago.

In the passage of the heat-supplying medium through the heat supply region 6, the medium cools down accordingly, for example. From temperature T1 to a lower temperature T2. In the lower heat dissipation area 7, however, heat, as indicated by arrow 9, for example, by means of a return of a cooling system, cooling circuit or a return / reinjection after thermal use or by cooling, for example, by means of air, water, groundwater dissipated. In doing so, the heat transport medium passing through the heat removal region 7, for example, from a temperature T3 to a higher temperature T4, heats up. The lower plate 5 can deliver the heat to the heat transfer medium either by direct or indirect heat conduction contact or by thermal radiation.

In particular, when using a plurality of thermocouple, the power generating device, for example, in industrial-technical environment for power generation are used and it can basically any type of heat source or residual heat in cooling systems, cooling systems, cooling circuits or the like will be used to generate electrical energy. The power generating device 1 can also be used in other embodiments in other heat transport devices, such as. A geothermal plant 1 1 with, for example. Downstream geothermal power plant 15 and even, for example. For individual houses 16 which are connected to a district heating network (FIGS. 2 and 3) , A geothermal plant 11, as shown in FIGS. 2 and 3, generally has a production well from which hot water for a feed 12 is taken and a re-injection well through the (cold) water through a (colder) return 13 back into the earth is pumped to reheat. In this case, the flow 12 and the return line 13 form their own geothermal cycle A, which is separated, for example, by a heat exchanger WT from a district heating circuit B, which supplies a geothermal power plant 15 and houses 16 with heat.

Via the heat exchanger WT, the heat from the earth via a flow line 18 to the geothermal power plant 15 and to the individual houses 16. The geothermal power plant 15 and the houses 16 remove as a heat consumer via appropriate heat exchanger heat from the flow line 18, with a heat transport medium such as water filled is. The cooled by the heat removal water is then fed back to the heat exchanger WT by means of a return line 19 and then there, depending on the temperature, again pumped by the return 13 of the Goethermiekreislaufes A through the re-injection well into the earth (and reheated there). The power generating device, which is designated in each case as TEG in Fig. 3, can now be placed at various points both in the geothermal cycle A and in the district heating cycle B for thermoelectric energy production (TEG). The power generation facilities are placed so that an existing functional and operational temperature difference is used. With this additional use of heat, the return is further cooled and thus better exploited the geothermal energy already produced.

The power generating device can be used, for example, between the flow 12 and the return line 13 in the geothermal cycle or even in the return 13. Here, for example, the power generating device 1 can be used to further cool the return line 13. In this case, for example, the return 13 is guided into the heat supply region 6 of the power generation device 2 (see FIG. 1), so that residual heat in the return flow 13 can be released there. For example, groundwater or air or another coolant that is colder than the return temperature can be used on the heat removal side 7, so that a corresponding temperature difference can be produced for power generation.

In a similar manner, for example, the power generating device 1 can be used for further cooling of the return from the geothermal power plant 15 or, for example, to further cooling the returns 17 of the respective houses 16. In this case also the respective return of the geothermal power plant 15 and the returns 17 of the houses 16 led into the heat supply region 6 of the power generating device 1, so that there can be given residual heat and used to generate electricity. On the heat dissipation side 7, for example, the heat can be dissipated by means of groundwater, air cooling or the like. In addition, the power generating device 1 can also be used in each case between the supply and return of the geothermal power plant 15 or the houses 16. In these cases, the respective flow into the heat supply region 6 and the return is guided by the heat removal region 7 of the power generating device 1.

In principle, therefore, the power generating device 1 can always be used when a temperature difference suitable for generating power can be produced.

Thus, in some embodiments at least one thermocouple 2 or at least one power generation device 1 can be used in combination with photovoltaic elements / plates and / or photovoltaic components.

A photovoltaic system normally consists of a plurality of photovoltaic elements, of which a single photovoltaic element 20 is shown schematically in FIG. Solar radiation 22 impinges on a front side 21 of the photovoltaic element 20 and we are then converted into electrical energy in the photovoltaic element 20.

By the solar radiation 21, the photovoltaic element is considerably heated, which significantly reduces its efficiency. When mounted on a roof 25 is carried out by the rear ventilation, that is, on the shadow side of the photovoltaic element 20 along flowing air flow 24, a cooling on the shadow side of the photovoltaic elements 22nd

This produces a temperature difference between a rear side 23 of the photovoltaic element 22 and the area 7 cooled behind it by air flow 24. By a corresponding arrangement of a power generation device 1, as explained in connection with FIG. 1, the heat generated by the solar radiation can be used further.

For this purpose, the power generation device 1 with the upper plate 4 in thermal contact with the back 23 of the photovoltaic element 22, ie in the Heat supply region 6 of the power generation device 1, arranged. As a result, the heat at the rear side 23 of the photovoltaic element 22 can be transmitted to the semiconductor material 3 via the plate 4.

The lower plate 4 on the cold side of the thermocouple 2 is cooled by the air flow 24, which flows in a heat removal region 7. This results in a corresponding temperature difference in the power generation device 1, which can be used to generate electricity. Consequently, the unconverted heat from the photovoltaic element 22 is further converted into electrical energy. By the heat dissipation of the power generating device 1 from the back 23 of the photovoltaic element 22, the photovoltaic element 22 is additionally cooled and thereby increases its efficiency.

Consequently, the efficiency of a photovoltaic system can be correspondingly increased by the corresponding use of the power generation device 1.

In some embodiments, a plurality of photovoltaic elements and a corresponding plurality of thermocouples or power generation devices are combined in an array to provide the largest possible photovoltaic system.

Claims

PROTECTION CLAIMS

A power generation apparatus comprising: at least one thermocouple (2) having a first surface (4) for receiving heat and a second surface (5) for emitting heat and being adapted to cause a temperature difference between the first (4) and generate the second surface (5) electrical energy; at least one heat supply section (6) supplying heat to the first surface (4) of the at least one thermocouple (2); and at least one heat dissipating portion (7) for dissipating heat from the second surface (5) of the at least one thermocouple (2).

A power generating device according to claim 1, wherein the thermocouple (2) comprises a semiconductor material (3).

3. A power generation apparatus according to any one of the preceding claims, further comprising an array having a plurality of thermocouples, wherein the thermocouples are electrically connected in series.

4. Heat transport device, in particular a geothermal, district heating or cooling system, comprising a power generating device (1) according to one of the preceding claims, wherein the Wäetwransportvorrichtung has a heat-carrying transport circuit with a heat transport medium, the transport circuit at least one flow (12, 18) and a return ( 13, 17, 19), wherein the heat transport medium in the flow (12, 18) has a higher temperature than in the return (13, 17, 19), the flow (12, 18) at least partially in the heat supply region (6) of the power generating device ( 1), and the return (13, 17, 19) at least partially in the heat dissipation of the Power generating device (7) is arranged.

5. A photovoltaic device for generating electricity, comprising a power generating device (1) according to one of claims 1 to 4, wherein the photovoltaic device comprises at least one photovoltaic element (20) having a front side (21) for catching sun rays and a back (23); the rear side (23) of the at least one photovoltaic element (20) is arranged at least partially in the heat supply region (6) for the at least one thermocouple (2); and the heat removal area (7) at least partially by a fluid (24), in particular air or water, is flowed through.

A photovoltaic device according to claim 5, comprising a plurality of photovoltaic elements (20) and a corresponding plurality of thermocouples (2), wherein at least one thermocouple (2) is disposed on each back side of a photovoltaic element (22).

7. Photovoltaic device according to claim 5 or 6, wherein the thermocouple (2) is arranged in a thermally conductive contact with the photovoltaic element (22).