Solar thermal energy generating plant and method for
obtaining energy by means of a solar thermal energy
generating plant
5 The invention relates to a solar thermal energy
generating plant comprising a first solar array, using
water as a heat transfer medium, a water separator,
arranged downstream of the first solar array, and a
high-pressure turbine.
10
The invention also relates to a method for obtaining
energy by means of a solar thermal energy generating
plant, in which steam is generated in a first solar
array, using water as a heat transfer medium, the steam
15 generated in the solar array is fed to a water
separator, in which a fraction of water is extracted
from the steam, and the steam leaving the water
separator is fed to a high-pressure turbine.
20 Solar thermal energy generating plants with linefocussing
solar technology, such as for example
parabolic trough technology or Fresnel technology, are
usually operated in such a way that a thermal oil flows
through a solar array, the thermal oil is heated in the
25 solar array by the inflowing solar energy and this
heated thermal oil is subsequently used outside the
solar array for transforming water into a vaporous
state, in order to feed this steam to a turbine or to a
number of turbines for generating energy. However, due
30 to the use of the thermal oil and the circuit necessary
for it, this method is complex and expensive.
In order to solve this problem there have been
developed solar thermal energy generating plants in
35 which thermal oil is not used as the heat transfer
medium in the solar array but instead water, which is
heated directly in the solar array in such a way that
it is transformed into a vaporous state, in particular
into saturated steam, and after passing a water
ORIGIN6'
- 2 -
separator is fed directly to the means of obtaining
energy, i.e. the downstream high-pressure turbine. The
fact that an own circuit for the thermal oil as the
heat transfer medium is no longer necessary here means
5 that the size of the plant can be reduced
significantly, which in turn leads to a lowering of the
costs. A disadvantage of the previously known solar
thermal energy generating plants with solar arrays that
use water as a heat transfer medium is, however, the
10 previously relatively low achievable efficiency in
respect of energy generation.
The object of the invention is therefore to provide a
solution by means of which the efficiency of solar
15 thermal energy generating plants using water as a heat
transfer medium can be increased.
In the case of a solar thermal energy generating plant
of the type referred to more specifically at the
20 beginning, the object is achieved according to the
invention by a first superheater for overheating the
steam leaving the water separator being arranged
between the water separator and the high-pressure
turbine.
25
In the case of a method of the type referred to in more
detail at the beginning, the object is achieved
according to the invention by the steam being fed to a
first superheater, in which the steam leaving the water
30 separator is overheated, before entering the highpressure
turbine.
Expedient refinements and advantageous developments of
the invention are specified in the subclaims.
35
The provision of a first superheater before the steam
enters the high-pressure turbine has the effect that
the steam entering the superheater as saturated steam
is heated, in particular overheated, and transformed
ORIGIN A
- 3 -
into what is known as live steam, the live steam having
a higher temperature and a lower moisture content than
the saturated steam entering the superheater. This
allows the efficiency in respect of energy generation
5 in the downstream high-pressure turbine to be increased
significantly. The overheating of the saturated steam
in the first superheater also allows the avoidance of
droplet erosion on the blades of the downstream highpressure
turbine due to the steam introduced into the
10 high-pressure turbine, whereby the effects of wear on
the high-pressure turbine can be reduced and the
lifetime of the high-pressure turbine can be increased
as a result.
15 According to an advantageous refinement of the
invention, a medium-pressure turbine or a low-pressure
turbine is arranged downstream of the high-pressure
turbine, a second superheater being arranged between
the high-pressure turbine and the medium-pressure
20 turbine or between the high-pressure turbine and the
low-pressure turbine. The steam leaving the highpressure
turbine can consequently be fed to a second
superheater before entering a downstream mediumpressure
turbine or a downstream high-pressure turbine,
25 so that the steam is overheated once again after
leaving the high-pressure turbine, whereby its
temperature is increased again before entering the
downstream medium-pressure turbine or low-pressure
turbine, and the efficiency of the energy generating
30 plant as a whole can be increased further as a result.
Alternatively, it is provided with preference that a
medium-pressure turbine is arranged downstream of the
high-pressure turbine and a low-pressure turbine is
35 arranged downstream of the medium-pressure turbine, a
second superheater being arranged between the highpressure
turbine and the medium-pressure turbine and a
third superheater being arranged between the mediumpressure
turbine and the low-pressure turbine. The
ORIGINAL
- A -
steam leaving the high-pressure turbine can
consequently be overheated in a second superheater
before entering the medium-pressure turbine arranged
downstream of the high-pressure turbine and can be
5 overheated a further time in a third superheater after
leaving the medium-pressure turbine and before entering
the downstream low-pressure turbine. This allows the
efficiency of the energy generating plant to be
increased further.
10
It is also alternatively possible that a thermal
storage unit or a seawater desalination plant or an
adsorption refrigeration machine is arranged downstream
of the high-pressure turbine, a second superheater
15 being arranged between the high-pressure turbine and
the thermal storage unit or the seawater desalination
plant or the adsorption refrigeration machine. The
steam leaving the high-pressure turbine can
consequently be fed to a thermal storage unit or a
20 seawater desalination plant or an adsorption
refrigeration machine, and be further used there,
directly or after passing a downstream medium-pressure
turbine and/or a low-pressure turbine. The thermal
storage unit may be, for example, a steam storage unit,
25 a warm water storage unit, an oil or salt storage unit.
Furthermore, the steam may also be used for feeding
into a district heating or process heating system.
According to a further advantageous refinement of the
30 invention, the first superheater and/or the second
superheater and/or the third superheater is/are a
steam-steam heat exchanger.
In the case of the steam-steam heat exchanger, the
35 steam is overheated with a steam before entering the
high-pressure turbine and/or medium-pressure turbine
and/or low-pressure turbine. The steam-steam heat
exchanger is preferably designed as a condenser.
ORIGINAL
- 5 -
For generating the additional steam, an additional
solar array may be provided, by means of which the
steam-steam heat exchanger can be operated. In the
additional solar array, in which water is likewise used
5 as a heat transfer medium, steam that has a higher
temperature and a higher pressure than steam leaving
the first solar array is generated, so that the steam
leaving the first solar array can be overheated by
means of the steam generated by the additional solar
10 array, whereby the cost-effectiveness of the method and
the energy generating plant can be increased further.
It is also possible that the first superheater and/or
the second superheater and/or the third superheater
15 is/are a second solar array, so that the steam is
passed through a second solar array, in which the steam
is overheated, before entering the high-pressure
turbine and/or medium-pressure turbine and/or lowpressure
turbine, and as a result its temperature is
20 increased before entering the downstream high-pressure
turbine and/or medium-pressure turbine and/or lowpressure
turbine.
Furthermore, it is provided with preference that a
25 combustion chamber is arranged downstream of the first
superheater and/or second superheater and/or third
superheater formed as a steam-steam heat exchanger
and/or the first superheater and/or second superheater
and/or third superheater formed as a second solar
30 array, so that, after the steam has left the
superheater and before it is conducted into a highpressure
turbine and/or medium-pressure turbine and/or
low-pressure turbine, the steam is passed through a
combustion chamber and further heated there, in
35 particular overheated, it being possible by means of
the combustion chamber for the temperature of the steam
before entering the high-pressure turbine and/or
medium-pressure turbine and/or low-pressure turbine to
be regulated very exactly, and consequently the steam
ORIGINAL
- 6 -
to be conditioned. Gas, oil, coal, biomass or biogas
may be used for example as the fuel in the combustion
chamber.
5 It is furthermore also possible that the first
superheater and/or the second superheater and/or the
third superheater is/are themselves formed as a
combustion chamber.
10 The invention is explained in more detail below on the
basis of preferred embodiments with reference to the
accompanying drawings, in which:
Figure 1 shows a schematic representation of a solar
15 thermal energy generating plant according to
the invention in a first embodiment,
20
Figure 2 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a second embodiment,
25
Figure 3 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a third embodiment,
Figure 4 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a fourth embodiment,
30 Figure 5 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a fifth embodiment,
Figure 6 shows a schematic representation of a solar
35 thermal energy generating plant according to
the invention in a sixth embodiment,
ORIGINAL
- 7--
Figure 7 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a seventh embodiment,
5 Figure 8 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in an eighth embodiment,
Figure 9 shows a schematic representation of a solar
10 thermal energy generating plant according to
the invention in a ninth embodiment,
Figure 10 shows a schematic representation of a solar
thermal energy generating plant according to
15 the invention in a tenth embodiment,
Figure 11 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in an eleventh embodiment,
20
Figure 12 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a twelfth embodiment,
25 Figure 13 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a thirteenth embodiment,
Figure 14 shows a schematic representation of a solar
30 thermal energy generating plant according to
the invention in a fourteenth embodiment,
Figure 15 shows a schematic representation of a solar
thermal energy generating plant according to
35 the invention in a fifthteenth embodiment,
and
ORIGINA!
- 8 -
Figure 16 shows a schematic representation of a solar
thermal energy generating plant according to
the invention in a sixteenth embodiment.
5 Figure 1 shows a schematic representation of a solar
thermal energy generating plant according to the
invention as provided by a first embodiment. Here,
steam is generated in the form of saturated steam in a
first solar array 10, using water as a heat transfer
10 medium, and after leaving the first solar array 10 is
fed to a first water separator 12, in which water still
contained in the steam is separated and returned to the
first solar array 10. The steam is subsequently fed to
a first superheater 14, which in the case of the
15 embodiment shown here is formed as a steam-steam heat
exchanger. In the first superheater 14, the steam is
overheated, so that the saturated steam entering the
superheater 14 is transformed into what is known as
live steam, with a higher temperature and a lower
20 moisture content than the saturated steam.
Subsequently, the steam is fed to a high-pressure
turbine 16 and a medium-pressure turbine or lowpressure
turbine 18, 20, which are connected to a
generator 22. The first superheater 14, formed as a
25 steam-steam heat exchanger, is operated with a steam
(saturated steam) generated in an additional solar
array 24, the steam generated in the additional solar
array 24 having a higher temperature and a higher
pressure than the steam generated in the first solar
30 array 10. Preferably, the steam generated in the first
solar array 10 has a pressure of 60 bar and the steam
generated in the additional solar array 24 has a
pressure of 80 bar. Arranged between the additional
solar array 24 and the first superheater 14 is a second
35 water separator 26, in which water is separated from
the steam leaving the additional solar array and is
returned to the additional solar array 24.
ORIGINAL
- 9 -
The second embodiment, shown in Figure 2, corresponds
substantially to the embodiment shown in Figure 1, a
second superheater 28, which is formed as a steam-steam
heat exchanger, being additionally provided here
5 between the high-pressure turbine 16 and the mediumpressure
turbine 18 or the low-pressure turbine 20. The
second superheater 28 is likewise operated with steam
(saturated steam) generated in the additional solar
array 24, in order to overheat again the steam leaving
10 the high-pressure turbine 16 before entering the
medium-pressure turbine 18 or the low-pressure turbine
20.
The third embodiment, shown in Figure 3, corresponds
15 substantially to the second embodiment, shown in Figure
2, a medium-pressure turbine 18 and a low-pressure
turbine 20 being provided here, and a third superheater
30 in the form of a steam-steam heat exchanger, which
is likewise operated with the steam (saturated steam)
20 generated in the additional solar array 24, being
formed between the medium-pressure turbine 18 and the
low-pressure turbine 20, in order to overheat again the
steam leaving the medium-pressure turbine 18 before
entering the low-pressure turbine 20.
25
The fourth embodiment, shown in Figure 4, corresponds
substantially to the first embodiment, shown in Figure
1, a combustion chamber 32 being additionally arranged
here directly downstream of the first superheater 14,
30 it being possible by means of the combustion chamber 32
for the steam leaving the first superheater 14 to be
conditioned before entering the high-pressure turbine
16.
35 The fifth embodiment, shown in Figure 5, corresponds
substantially to the third embodiment, shown in Figure
3, a combustion chamber 32 also being arranged here
downstream of the first superheater 14.
ORIGINAL
- 10 -
The sixth embodiment, shown in Figure 6, corresponds
substantially to the fifth embodiment, shown in Figure
5, a combustion chamber 32 being additionally arranged
here respectively downstream of the second superheater
5 28 and the third superheater 30.
In the case of the seventh embodiment, shown in Figure
7, a first superheater 14 in the form of a steam-steam
heat exchanger is arranged between the water separator
10 12 and the high-pressure turbine 15. In the case of
this embodiment, the first superheater 14 is operated
with steam from the first solar array 10, in that the
steam after leaving the water separator 12 is separated
into steam that is overheated in the first superheater
15 14 and subsequently fed to a high-pressure turbine 16
and steam that is used for the overheating. After the
branching and before entering the first superheater 14,
a throttling 34 is provided in the form of an
isenthalpic throttling, in which the temperature of the
20 steam before entering the first superheater 14 is
lowered. In the first superheater 14 itself, with the
enthalpy remaining the same a lowering of the pressure
then takes place, thereby in turn increasing the
temperature of the steam, which is subsequently fed to
25 the high-pressure turbine 16. Provided between the
high-pressure turbine 16 and the medium-pressure
turbine 18 or low-pressure turbine 20 is a second
superheater 28, which is likewise formed as a steamsteam
heat exchanger and is operated with the steam
30 branched off from the first solar array 10 for
overheating the steam leaving the high-pressure turbine
16.
The eighth embodiment, shown in Figure 8, has a first
35 superheater 14, taking the form of a combustion
chamber. An additional solar array is not necessary in
the case of this embodiment.
ORIGINAL
- 11 -
The ninth embodiment, shown in Figure 9, likewise has a
first superheater 14, taking the form of a combustion
chamber. A second superheater 28, in the form of a
steam-steam heat exchanger, is additionally provided
5 between the high-pressure turbine 16 and the mediumpressure
turbine 18 or the low-pressure turbine 20.
This second superheater 28 is operated with a steam
branched off from the steam leaving the first
superheater 14, so that the steam leaving the high-
10 pressure turbine 16 is overheated with an overheated
steam leaving the first superheater 14 before entering
the medium-pressure turbine 18 or low-pressure turbine
20.
15 In the case of the tenth embodiment, shown in Figure
10, a high-pressure turbine 16, a medium-pressure
turbine 18 and a low-pressure turbine 20 are provided,
the steam being overheated in a first superheater 14
before entering the high-pressure turbine 16, being
20 overheated in a second superheater 28 before entering
the medium-pressure turbine 18, and being overheated in
a third superheater 30 before entering the low-pressure
turbine 20. In this case, the first superheater 14, the
second superheater 28 and the third superheater 30
25 respectively take the form of a combustion chamber.
Figure 11 shows an eleventh embodiment, in which the
first superheater 14 is formed as a combustion chamber
and a second superheater 28 in the form of a second
30 solar array is formed between the high-pressure turbine
16 and the medium-pressure turbine 18 or low-pressure
turbine 20. Consequently, in the case of this
embodiment, the steam leaving the high-pressure turbine
16 is conducted through a second superheater 28 in the
35 form of a second solar array, in which the steam is
overheated, before entering the medium-pressure turbine
18 or the low-pressure turbine 20.
ORIGH
- 12 -
Figure 12 shows a twelfth embodiment, in which the
first superheater 14 takes the form of a second solar
array, so that the steam leaving the water separator 12
is fed to a second solar array and overheated there
5 before entering the high-pressure turbine 16.
The thirteenth embodiment, shown in Figure 13,
corresponds substantially to the twelfth embodiment,
shown in Figure 12, a second superheater 28 in the form
10 of a combustion chamber being additionally provided
here between the high-pressure turbine 16 and the
medium-pressure turbine 18 or the low-pressure turbine
20.
15 The fourteenth embodiment, shown in Figure 14,
corresponds substantially to the thirteenth embodiment,
shown in Figure 12, a combustion chamber 32 for
conditioning the steam leaving the first superheater 14
before entering the high-pressure turbine 16 being
20 arranged here downstream of the first superheater 14,
formed as a second solar array.
In the case of the embodiment shown in Figure 15, the
steam is divided after leaving the water separator 12,
25 one part of the steam being fed to a first superheater
14, formed as a second solar array, and the other part
of the steam being fed to a second superheater 28,
formed as a steam-steam heat exchanger, in order to
overheat the steam leaving the high-pressure turbine
30 16.
The sixteenth embodiment, shown in Figure 16,
corresponds substantially to the thirteenth embodiment,
shown in Figure 13, the second superheater 28 not being
35 formed here as a combustion chamber but as a further
second solar array.

Patent claims
1. A solar thermal energy generating plant, with
a first solar array (10), using water as a heat
5 transfer medium,
a water separator (12), arranged downstream of the
first solar array (10), and
a high-pressure turbine (16),
characterized in that
10 a first superheater (14) for overheating the steam
leaving the water separator (12) is arranged
between the water separator (12) and the highpressure
turbine (16).
15 2. The solar thermal energy generating plant as
claimed in claim 1, wherein a medium-pressure
turbine (18) or a low-pressure turbine (20) is
arranged downstream of the high-pressure turbine
(16), a second superheater (28) being arranged
20 between the high-pressure turbine (16) and the
medium-pressure turbine (18) or between the highpressure
turbine (16) and the low-pressure turbine
(20) .
25 3. The solar thermal energy generating plant as
claimed in claim 1, wherein a medium-pressure
turbine (18) is arranged downstream of the highpressure
turbine (16) and a low-pressure turbine
(20) is arranged downstream of the medium-pressure
30 turbine (18), a second superheater (28) being
arranged between the high-pressure turbine (16) and
the medium-pressure turbine (18) and a third
superheater (30) being arranged between the mediumpressure
turbine (18) and the low-pressure turbine
35 (20).
4. The solar thermal energy generating plant as
claimed in claim 1, wherein a thermal storage unit
or a seawater desalination plant or an adsorption
refrigeration machine is arranged downstream of the
high-pressure turbine (16), a second superheater
(28) being arranged between the high-pressure
turbine (16) and the thermal storage unit or the
seawater desalination plant or the adsorption
refrigeration machine.
5. The solar thermal energy generating plant as
claimed in one of claims 1 to 4, wherein the first
superheater (14) and/or the second superheater (28)
and/or the third superheater (30) is/are a steamsteam
heat exchanger.
6. The solar thermal energy generating plant as
claimed in claim 5, wherein an additional solar
array (24) is provided, by means of which the
steam-steam heat exchanger can be operated.
7. The solar thermal energy generating plant as
claimed in one of claims 1 to 6, wherein the first
superheater (14) and/or the second superheater (28)
and/or the third superheater (30) is/are a second
solar array.
8. The solar thermal energy generating plant as
claimed in claim 6 or 7, wherein a combustion
chamber (32) is arranged downstream of the first
superheater (14) and/or second superheater (28)
and/or third superheater (30) formed as a steamsteam
heat exchanger and/or the first superheater
(14) and/or second superheater (28) and/or third
superheater (30) formed as a second solar array.
9. The solar thermal energy generating plant as
claimed in one of claims 1 to 7, wherein the first
superheater (14) and/or the second superheater (20)
and/or the third superheater (30) is a combustion
chamber.
10. A method for obtaining energy by means of a solar
thermal energy generating plant, in which steam is
generated in a first solar array (10), using water
as a heat transfer medium, the steam generated in
5 the first solar array (10) is fed to a water
separator (12), in which a fraction of water is
extracted from the steam, and the steam leaving the
water separator (12) is fed to a high-pressure
turbine (16), characterized by the steam is fed to
10 a first superheater (14), in which the steam
leaving the water separator (12) is overheated,
before entering the high-pressure turbine (16).