DE102007027349B4 - Device and method for generating electricity from heat - Google Patents

Abstract

The invention relates to a device and a method for generating electricity from heat, with a generator and the dynamics of a moving medium receiving turbine, according to the preamble of claim 1 and 15. In this case to achieve that the coupling between the turbine and generator free of said mechanical Disadvantages, and the energy consumption and ultimately the energy conversion from the medium is more effectively used, the invention proposes that the turbine (3) or the turbine wheel (11) and the generator (4) on a common and / or jointly supported axis ( A) are arranged.

Description

The The invention relates to a device and a method for generating electricity from heat, with a generator and the dynamics of a moving medium receiving turbine, according to preamble of claim 1 and 14.

In the generation of electrical energy from the dynamics of a moving medium, the dynamics of the medium receiving turbine wheel is often connected via a gearbox with the power generator. This applies both to slow-running turbine wheels such as in the wind energy intake, but also in steam power plants. There are used equally gear for motion coupling. These should lead to a homogenization between turbine speed and generator speed by appropriate reduction or translation. It is already known to dispense with a turbine-generator coupling in the case of a gas turbine to a gear arranged therebetween. Such a device is from the EP 1 367 690 B1 known for a specific application. From the DE 10 2006 004 836 A1 a device is known in which lie according to the generic term turbine and generator already on a common axis. However, this is not sufficient to make this coupling in particular effective enough for technical integration in low-temperature ORC systems. This requires further efficiency-increasing measures.

Of the Invention is therefore based on the object, a device of generic type to evolve to that the coupling between turbine and generator free of mechanical Disadvantages is, and the energy intake and ultimately the energy conversion from the medium is more effectively usable.

The asked task is in a device of the generic type according to the invention the characterizing features of claim 1 solved. Further advantageous embodiments are specified in the dependent claims 2-13.

Regarding a method is the task according to the invention by solved the characterizing features of claim 14.

Further advantageous embodiments are given in the dependent dependent claims.

The core of the invention is that when used in an ORC low-temperature system, the pump ( 5 ) also on the common and / or jointly supported axis A together with the generator ( 4 ) and the turbine ( 3 ) or the turbine wheel ( 11 ) of the turbine ( 3 ) is arranged. This is a significant functional difference to the subject of the cited EP 1 367 690 B1 from the only known, the axes rotatably and thus coupling gear free with each other. However, in the prior art, this leads to the fact that each component, namely the generator and the turbine, each have a separately supported axis, which are coupled to one another by means of a single contact. However, since each axis is stored for itself, this leads to a mechanical overdetermination of the bearing or support points. Thus, an absolute unbalance-free synchronization would only be achievable if the connection of the turbine axis and the generator axis rotatorisch rotationally fixed, but axially balancing, ie would compensate for axial balancing. Although the connection would be gearless, but this axle compensation would be subject to wear and also swallows friction energy.

All These disadvantages are eliminated by the design according to the invention, in which the turbine and the generator on a common and jointly mounted axis are arranged. Achsausgleiche completely eliminated and only then does an absolute smooth synchronization take place.

In Another advantageous embodiment is specified that the turbine is a radial centripetal turbine which is laterally to the axis of rotation streamed with the medium and the medium in the axial direction can be centrally flowed out of the turbine. This is structurally particular for compact systems of considerable advantage. Another advantage lies doing so in the optimal efficiency of such a turbine wheel construction, which is provided with curved laterally approaching blades.

In Another advantageous embodiment is specified that the generator a brushless, preferably a generator with permanent magnets. There are the frictional resistance significantly lower than with a generator with brushes.

Advantageous is also an embodiment in which the axis with magnetic or Air bearings is stored. this leads to to a further reduction of frictional resistance, what the efficiency of Energy conversion in turn increased. Air bearings are sections on bearing shafts that are surface-textured. This happens at higher levels Speeds to an air cushion on which the bearing shaft or the stored Wave then runs.

All of these advantages already achieved correspond particularly well with an embodiment in which the turbine-generator arrangement according to the invention is integrated in a low-temperature ORC system. Here is the compact and extremely quiet turbine-generator arrangement, and the Measures to reduce friction losses particularly effective.

In advantageous embodiment is specified that the low-temperature ORC plant (Organic Rankine Cycle) as well at least one evaporator stage, at least one condensation stage, and a pump for the return of the condensed medium from the condenser stage to the evaporator stage having. This means that all components are in a closed circuit integrated, in particular the turbine-generator arrangement works thereby optimized.

A special embodiment is that the pump also on the common and / or co-managed axis together with the generator and the turbine is arranged. This can be the ORC system be built extremely compact. For the construction realization only the wirings be made accordingly, but that is completely problem-free. By the co-arrangement of the return pump for the circulating medium on the same axis as turbine and generator, thus accounts for conversion losses of otherwise existing electrical Assemblies. The pump is mechanically directly connected to the power of the be streamed Turbine taken. Overall, this increases the overall efficiency, which is clearly visible in the energy balance.

In Another advantageous embodiment is specified that as a medium niedertemperturverdampfende fluorinated hydrocarbons used become. These media evaporate at room temperature or already underneath. When operating the system at an evaporation temperature well above room temperature This works with good pressure values to an effective flow of To produce turbine.

One Particularly advantageous material for use as a medium is 1,1,1,33-pentafluoro-propane.

A Another useful alternative is butane as a medium.

Around now the ORC plant in optimal ecological Principle to operate, d. H. with alternative energy sources to Heating of the evaporator, in one embodiment, the evaporator via a heat exchanger heated, which consists of a heat transfer medium (water or thermal oil) from solar panels is operable. Plants of this type have it even a huge utility for private applications in residential buildings. Sun heat can be more conventional Solar panels heat at least partially electricity, and feed the electricity into the power grid. An inventive device according to this Design has a very good efficiency. As if combined Equipment relating to elective or combined heat and power generation it is competitive with semiconductor solar cell systems.

A Another advantageous embodiment is that evaporator over a heat exchangers is heated, which in turn can be heated from waste heat. So can the said device is also used there and used, where energy in the form of waste heat accrues, then over This ORC technological design is converted into electricity.

In Another advantageous embodiment is specified that evaporator as well as the solar panel or the solar panels a common closed Have medium circulation, such that the evaporator medium without Heat exchanger directly in the tubes of the solar panels are heatable. This requires there is no heat exchanger more because in the tubes of the solar panels there is no more water, but already the evaporator medium is flowing and the temperature is direct receives. It is important to ensure that the pipes for the accruing Pressure is designed and tight. By eliminating the evaporator heat exchanger the efficiency is further increased because the thermal energy losses omitted.

A last advantageous embodiment is that while the Capacitor stage as a tube bundle or as a kind of heat sink with folded surface is trained over which the heat release to the environment, to a house heating, in a district heating network or deliverable in a heat storage is.

With In other words, the cooling takes place of the capacitor by heat exchange with the environment, or in the manner specified above.

A Establishment of this kind also has a significant benefit in terms of on climate-friendly energy generation.

in the With regard to a method of the generic type, the core of the Invention in that the evaporation temperature T2 in the evaporator in operation between 50 ° C and 130 ° C is and is set, and that after passing through the medium through the turbine is cooling off at least 30K.

In further inventive embodiment of the method is indicated that the evaporation temperature T2 preferably at about 70 ° C is set.

In a further advantageous embodiment, a temperature control is specified, in which the Condensation cooling in the condenser is cooled by a heat exchanger at approximately the return temperature T1 of the medium to the evaporator, such that the temperature differences .DELTA.T between return temperature T1 and evaporator temperature T2, are the same in both directions.

In last advantageous embodiment is indicated that at the condensation cooling resulting waste heat used as heating energy or at the obtained temperature level is nachverstromt separately.

The The invention is illustrated in the drawing and explained in more detail below.

It shows:

1 : Embodiment with turbine and generator on one axis.

2 : Radial centripetal turbine.

3 Embodiment with turbine, generator and recirculation pump on one axis.

4 Embodiment with integration of the evaporator stage directly in solar panels.

1 shows a first embodiment in which the turbine of the turbine 3 are arranged with the generator on a physically common axis A. It should be noted here that, in contrast to the prior art described above, the turbine and the generator do not each have two separate axes, which are coupled to each other. Because this leads to a stock overdetermination and thus to a rest rest of these two components.

According to the invention, the extended axis A of the generator 4 one with the axis of the turbine 3 or the turbine wheel 11 , Thus, the device is extremely smooth running and the coupling leads to the efficiency of the entire device increasing technical measure. The turbine wheel of the turbine 3 is with the help of the evaporator 1 outflowing evaporator medium, in this example 1,1,1,33-pentafluoro-propane, which in the evaporator by supplying heat through the evaporator heat exchanger 40 is brought to an evaporation temperature T1 and the turbine wheel of the turbine 3 flows against. The so-flowed turbine wheel absorbs this energy and through the rotationally fixed connection via the common axis A with the generator 4 , or the rotor of the generator 4 this is driven. The generator is z. B. formed as a brushless permanent magnet excited generator. The generated electrical energy is then at the output 10 at.

The turbine 3 is called a radial centripetal turbine with an in 2 later shown even closer turbine wheel 11 equipped, in which the medium is tangential to the turbine wheel 11 flowed in and then derived by a corresponding lamellae centrally. The medium flows into a condenser 2 via a heat exchanger 7 the medium cools down again. The heat absorbed in turn can be used again, or can be re-converted, or recycled.

The cooled and condensed medium is cooled down to a condensation temperature of T2 and via a return pump 5 back to the evaporator 1 pumped. This is externally supplied with heat and the process then continues. This means that the medium is in a closed cycle.

At the heat exchanger 7 At a low temperature, a coolant is passed through a heat exchange conduit. The at the heat exchanger 7 absorbed heat is thereby either used or recycled in the said manner.

Via a control valve 6 the circulation is regulated as a whole.

generator 4 and turbine 3 can also work in an assembly 20 to be housed.

An exemplary temperature control runs depending on the pressure and the medium used so that T1, ie the output temperature is about 70 ° C, in the condenser 2 then again cooled to T2, that is about 40 ° C and condensed, and at about this temperature level of T4 = T2 in about the evaporator again 1 is supplied.

At the entrance of the heat exchanger 7 A coolant is supplied at about T3 equal to 10 ° C and discharged to about T4 equal to 40 ° C again.

2 shows in detail, but only schematically the turbine wheel 11 , This is impinged on the edge approximately tangentially by the vaporized medium. The medium is led by the lamellar guide to the center of the turbine wheel and can flow out there centrally before it afterwards as in 1 is supplied to the capacitor.

3 shows a particularly advantageous embodiment, in which not only generator 4 and turbine 3 or turbine wheel 11 and rotor are arranged on a common physical axis A, but also the return pump 5 , This not only has the advantage of having the energy for the return pump 5 directly from the generated mechanical energy of the turbine wheel is applied, which further increases the efficiency, but the Design of the entire device is thereby even more compact.

In this case, as indicated here, the entire assembly turbine, generator and return pump standing upright between evaporator 1 and capacitor 2 to be placed. Due to the more compact design, only short media lines are required, which reduces heat losses and thus also increases efficiency even further. In addition, there is a small-scale device.

4 shows an embodiment in which instead of a separate evaporator 1 , the bottom side as in 1 represented thermal energy through the evaporator heat exchanger 40 must be fed, instead, now the evaporator in the tubes of a solar collector 30 is immediately integrated.

The tubes of the solar collector must be installed only pressure resistant and designed so that the absorbed solar energy, the medium, for example, the said penta-fluorine-propane readily in the tubes of the solar collector 30 is evaporated, and then the steam is fed directly to the turbine.

The further embodiment can then again according to 1 or 3 be educated. In both cases, the evaporator needs 1 only against a pressure-resistant solar collector 30 be replaced.

In In all embodiments, the Bearing the common axis also Magnetic or air bearing, which both increases the smoothness, as also greatly reduces the friction losses. Overall, too, increased this feature the achievable in the overall process efficiency.

The Use of butane or penta-fluoro-propane are exemplary only. Possible are all media with correspondingly low boiling point.

1

Evaporator

2

capacitor

3

turbine

4

generator

5

Pump, Recirculation pump

6

control valve

7

heat exchangers

10

output electrical energy

11

turbine

20

module

30

solar panel

40

Evaporator heat exchanger

A

axis

T1

outlet temperature Evaporator

T2

Return temperature to the evaporator

T3

inlet temperature heat exchangers

T4

outlet temperature heat exchangers

Claims (16)

A device for generating electricity from heat, comprising a generator and a dynamic fluid receiving turbine in which the turbine and the generator are coupled to each other gearless, wherein the turbine ( 3 ) or the turbine wheel ( 11 ) and the generator ( 4 ) are arranged on a common and / or jointly supported axis (A), characterized in that when used in an ORC low-temperature system, the pump ( 5 ) also on the common and / or jointly supported axis A together with the generator ( 4 ) and the turbine ( 3 ) or the turbine wheel ( 11 ) of the turbine ( 3 ) is arranged. Device according to claim 1, characterized in that the entire arranged on an axis assembly consisting of turbine / turbine wheel ( 3 . 11 ), Generator ( 4 ) and pump ( 5 ) standing upright between evaporator ( 1 ) and capacitor ( 2 ) is placed. Device according to claim 1 or 2, characterized in that the turbine ( 3 ) is a radial centripetal turbine, which flows laterally to the axis of rotation with the medium and the medium in the axial direction can be flowed out of the turbine centrally. Device according to claim 2 or 3, characterized in that the generator ( 4 ) is a brushless, preferably a generator with permanent magnets. Device according to one of the preceding claims, characterized characterized in that the axle (A) mounted with magnetic or air bearings is. Device according to one of the preceding claims, characterized in that the low-temperature ORC plant also at least one evaporator stage ( 1 ), at least one condensation stage ( 2 ), as well as a pump ( 5 ) for recycling the condensed medium from the condenser stage ( 2 ) to the evaporator stage ( 1 ) having. Device according to one of the preceding claims, characterized characterized in that the medium is low-temperature vaporizing fluorinated Hydrocarbons are used. Device according to claim 7, characterized that 1,1,1,33-pentafluoro-propane is used as the medium. Device according to claim 7, characterized Butane is used as a medium. Device according to one of the preceding claims 1 to 9, characterized in that the evaporator ( 1 ) is heatable via a heat exchanger, which is operable from a heat carrier (water or thermal oil) from solar panels. Device according to one of the preceding claims 1 to 9, characterized in that evaporator ( 1 ) is heatable via a heat exchanger, which in turn can be heated from waste heat. Device according to one of the preceding claims 1 to 9, characterized in that evaporator ( 1 ) as well as the solar collector ( 30 ) or the solar collectors have a common closed medium circuit, such that the evaporator medium without heat exchanger directly in tubes of the solar panels ( 30 ) is heatable. Device according to Claim 12, characterized in that the capacitor stage ( 2 ) is designed as a tube bundle or as a kind of heat sink with a folded surface, via which the heat transfer to the environment, to a house heating, in a district heating network or in a heat storage vornehmbar. Method for operating a device according to a the claims 1 to 13, characterized in that the evaporation temperature T2 is in the evaporator in operation between 50 ° C and 130 ° C and is set, and that after passing through the medium through the turbine a cooling to about 30 K takes place, and that the condensation cooling in the condenser via a heat exchangers in about the return temperature T1 of the medium is cooled to the evaporator, such that the Temperature differences ΔT between return temperature T1 and evaporator temperature T2 are equal in both directions. Method according to claim 14, characterized in that that the evaporation temperature T2 is preferably set at about 70 ° C. becomes. Method according to claim 14 or 15, characterized that in the condensation cooling resulting waste heat used as heating energy or separately at the temperature level obtained is nachverstromt.