Title of Invention

A METHOD AND A DEVICE FOR EXECUTING A THERMODYNAMIC CYCLE PROCESS

Abstract The invention relates to an disclose a method for executing a thermodynamic cycle process. To this end, the pressure of a liquid working substance flow (13) is increased and a first partially evaporated working substance flow (15) is produced by the partial condensation of a working substance flow (12) with a low surface tension. Further evaporation of the first partially evaporated working substance flow (15) with heat transmitted by an external heat source (20) produces a second at least partially evaporated working substance flow (18). In said second at least partially evaporated working substance flow (18), the vaporous phase (10) is separated from the liquid phase, the energy of the vaporous phase (10) is converted into a usable form, and a vaporous phase (11) with a low surface tension is combined with the liquid phase (19) in such a way as to form the working substance flow (12) with a low surface tension. The liquid working substance flow (13) is, in turn, obtained by complete condensation of the partially condensed working substance flow (12a) with a low surface tension.
Full Text SPECIFICATION :
FIELD OF THE INVENTION :
The invention relates to a method and a device for executing a thermodynamic
cycle process.
BACKGROUND OF THE INVENTION
Thermal power stations use thermodynamic cycle processes for converting heat
into mechanical or electrical energy. Conventional thermal power stations create
the heat by burning fuel, in particular the fossil fuels coal, oil and gas. The cycle
processes are operated in this case for example on the basis of the classic
Rankine cycle process with water as its working medium. Its high boiling point
however makes water unattractive, especially when using heat sources with
temperatures between 100° to 200°C, e.g. geothermal liquids or waste heat from
combustion processes, because the process is not cost effective.
For heat sources with such a low temperature a wide diversity of technologies
have been developed over recent years which make it possible to convert their
heat into mechanical or electrical energy with a high degree of efficiency. As well
as the Rankine process with organic working media (Organic Rankine Cycle,
ORC) a process known as the Kalina cycle process stands out above all by virtue
of its markedly better levels of efficiency compared to the classic Rankine
process. Various cycles for different applications have been developed on the
basis of the Kalina cycle process. Instead of water these cycles use a mixture of


two substances (e.g. ammonia and water) as their working medium, with the
non-isothermic boiling and condensation process of the mixture being utilized to
increase the efficiency of the cycle by comparison with the Rankine cycle.
For temperatures of the heat source of 100 to 140°C the Kalina cycle KCS 34
(Kalina Cycle System 34) is preferably used, which is employed for example in
the geothermal power plant at Husavik in Iceland (see also EP 1 070 830 Al). In
this cycle (see also Figure 3) a liquid working medium is pumped into a first heat
exchanger where it is heated up by a part condensation of an expanded working
medium flow. The heated working medium flow produced in this way is then
further heated up by cooling the liquid phase of a partly vaporized working
medium flow in a second heat exchanger and subsequently partly vaporized (e.g.
to a liquid content of 14 - 18%) in a third heat exchanger using heat transmitted
from an external heat source (e.g. a geothermal liquid). Then the liquid phase of
the partly vaporized working medium flow is separated from the vapor phase in a
separator.
The vapor phase is expanded in a turbine and its energy is used for generating
power. The liquid phase is directed through the second heat exchanger and used
for further heating of the heated working medium flow. In a mixer the liquid
phase and the expanded vapor phase are merged and the expanded working
medium flow already mentioned is formed. The expanded working medium flow
is subsequently partly condensed in the first heat exchanger and finally fully
condensed in a condenser so that the liquid working medium flow mentioned at
the start is created and the cycle is completed.


OBJECT OF THE INVENTION
Using this known cycle process as its starting point, the object of the present
invention is to specify a method and a device for executing a thermodynamic
cycle process, which, with the same external heat source and cooling water
temperature, and with plant costs which essentially remain the same, makes it
possible to produce the same or even a higher yield of mechanical energy.
SUMMARY OF THE INVENTION
The object to which the method is directed is successfully achieved in
accordance with the invention by a method as herein disclosed. The object to
which the device is directed is successfully achieved in accordance with the
invention by a device as herein described.
In accordance with the invention, by part condensation of the expanded flow of
working medium the pressurized liquid flow of working medium is not only
heated up but even partly vaporized. This is possible because, by comparison
with the KCS 34 cycle mentioned at the start, the second heat exchanger and
thereby the transmission of heat from the liquid phase of the partly vaporized
working medium flow for further heating or for part vaporization of the heated
working medium flow is dispensed with. This removes less heat in the liquid
phase which is subsequently used for better heating and partial vaporization of
the pressurized liquid working medium flow by part condensation of the
expanded working medium flow.


By suitably adapting the heating surfaces of the remaining heat exchangers and
other cycle parameters it is possible not only to keep the yield of mechanical
and/or electrical energy the same by comparison with the known cycle but even
to increase it. The costs of a possibly increased heating surface requirement in
the remaining heat exchangers could in this case be largely compensated for by
the omission of the second heat exchanger and the associated simplification of
the pipework, thus keeping the plant costs essentially the same.
By dispensing with the second heat exchanger mentioned at the start of
dispensing with a heat transfer from the liquid phase to the first partly vaporized
working medium flow, the device and the method in accordance with the
invention stand out because of they are less complex by comparison with the
prior art.
The part vaporization of the pressurized, liquid working medium flow by part
condensation of the expanded working medium flow can be favorably improved
by the pressure of the vapor phase amounting to less than 24 bar and thereby
being far less than the 33 bar figure known from previous cycles. In this way the
overall pressure level in the cycle can be reduced, which enables the boiling
temperature of the working medium in its turn to be reduced.
When the pressure of the vapor phase before entry into the turbine is three
times as great as the pressure of the expanded vapor phase it is also possible to
use conventional single stage expander turbines. These types of expander
turbines have levels of efficiency of up to 88% and thereby far greater levels of
efficiency than the multi-stage expander turbines previously used in these types
of cycles, e.g. designed for a maximum pressure of 33 bar with levels of


efficiency of appropriate 75%. A loss in the degree of efficiency possibly
associated with a reduction in the pressure level or the lower pressure ratio over
the expander turbine in the cycle is there by more than compensated for by the
better efficiency of the turbine and the greater possible throughout of working
medium which allows comparably more energy to be extracted from the thermal
water.
When a conventional single-stage expander turbine is used, the costs of a
second turbine stage or the additional costs for a specific turbine design for high
differences in pressure are also not incurred.
In accordance with an embodiment of the invention a multi substance mixture is
used as the working medium. The multi substance mixture is preferably a two
substance mixture, especially an ammonia-water mixture. As a result of the non-
isothermic vaporization and condensation of such a mixture an especially high
level of efficiency of the cycle can be achieved.
Energy can be obtained in an especially environmentally friendly way by using a
geothermal liquid, especially thermal water, from a geothermal source, as the
heat source. Waste gases (exhaust gases) from gas and/or steam turbine plants
can however also be used as the heat source or heat generated in industrial
production processes (e.g. in steel production) can be used.
A high level of efficiency of the cycle can in this case be achieved by the heat
source having a temperature of 100°C to 200°C, especially 100° to 140°C.


BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention as well as further advantageous embodiments of the invention are
explained in more detail below with reference to exemplary embodiments in the
accompanying figures, which show:
Figure 1 a circuit of an inventive device for executing a thermodynamic cycle
process in a simplified schematic presentation,
Figure 2 a cycle calculation for a device in accordance with Figure 1,
Figure 3 a circuit for a device known from the prior art for executing a
thermodynamic cycle process in a simplified, schematic
presentation,
DETAIL DESCRIPTION OF THE INVENTION
The device 1 shown in Figure 1 for executing a thermodynamic cycle process
features a (recuperative) heat exchanger HE4, which on the primary side has hot
thermal water 20 from a geothermal source not shown in any greater detail
flowing through it and is connected on the secondary side on the one hand to a
heat exchanger HE2 and on the other hand to a separator 4. The separator 4 is
used for separating a vapor phase from a liquid phase of a partly vaporized
working medium. A vapor-side output of the separator 4 is connected to a
turbine 2. The turbine 2 is connected on its output side to a mixer 5 which is still
connected with a liquid input of the separator 4. On the output side the mixer 5
is connected to the secondary side of a (recuperative) heat exchanger HE2 which
in its turn is connected to the primary side of a condenser HE1 through which


cooling water flows on the secondary side. The condenser HE1 is connected at
its primary-side output, if necessary via a condensing tank, via a pump 3 to the
primary side of the heat exchanger HE2. The primary side of the heat exchanger
HE2 is in its turn connected to the secondary side of the heat exchanger HE4
already mentioned.
A two-substance mixture of water and ammonia is used as the working medium
in the device 1, which thus exhibits a non-isothermic vaporization and
condensation. After the condenser HE1 the working medium is in a liquid state as
a liquid working medium flow 13. With the aid of the pump 3 the entire flow of
liquid working medium 13 is pumped up to a higher pressure and pressurized
liquid working medium flow 14 is created.
The pressurized liquid working medium flow 14 is fed to the primary side of the
heat exchanger HE2 and heated up and partly vaporized by part condensation of
a secondary-side expanded working medium flow 12 fed through the heat
exchanger HE2, so that on the primary side after the heat exchanger HE2 a first
partly vaporized flow of working medium 15 and on the secondary side a partly
condensed, expanded flow of working medium 12a are present. The proportion
of vapor in the first partly vaporized flow of working medium 15 is 15% for
example.
The first partly vaporized flow of working medium 15 is fed without further
heating to the secondary side of the heat exchanger HE4.
On the primary side hot thermal water 20 flows through the heat exchanger
HE4. In the heat exchanger HE4 the first partly vaporized working medium flow
15 is further vaporized by the cooling down of the thermal water 20 and a


second partly vaporized working medium flow 18 created. The second partly
vaporized working medium flow 18 is fed to the separator 4, in which the vapor
phase 10 is separated from the liquid phase 19 of the second partly vaporized
working medium flow 18. The vapor phase 10 is subsequently expanded in the
turbine 2 and its energy is converted into a usable form, e.g. into current by a
generator not shown in the figure and an expanded vapor phase 11 created.
In the mixer 5 the expanded vapor phase 11 and the liquid phase 19 separated
off in the separator 4 are merged again and an expanded working medium flow
12 is formed.
In this case no provision is made for an explicit transfer of heat from the liquid
phase 19 to the first partly vaporized working medium flow 15, e.g. by means of
a heat exchanger provided specifically for the purpose. The partly vaporized
working medium flow 15 thus, before its further vaporization in heat exchanger
HE4, has essentially the same temperature as it does after its creation by part
condensation of the expanded working medium flow 12. "Essentially the same
temperature" is taken in this case to mean that the temperature difference only
amounts to a few Kelvin and is caused for example by a slight cooling down of
the first partly vaporized working medium flow leaving heat exchanger HE2 as a
result of heat losses in the connecting pipes to heat exchanger HE4.
The expanded working medium flow 12 is partly condensed in heat exchanger
HE2 and a partly condensed, expanded working medium flow 12a created. The
partly condensed, expanded working medium flow 12 is subsequently condensed
in condenser HE1 with the aid of the (incoming) flow of cooling water 25 and the
liquid working medium flow 13 created. The heat transferred by the

condensation of the expanded working medium flow 12a to the cooling water
flow 25 is removed by the outgoing cooling water flow 26.
Figures 2 shows a cycle calculation for a device for execution of the
thermodynamic cycle process, which essentially corresponds to the device shown
in Figure 1 and has additionally only been supplemented by a number of valves
27. As initial conditions for the calculations an ammonia concentration in the
water of 95% (with a liquid, fully condensed working medium) and a thermal
water flow 20 with a temperature of 120°C as well as a mass flow of 141.8 kg/s
are assumed. The temperature of cooling water flow 25 is 9.4°C. As can be seen
from Figure 1 and 2, there is no provision for changes in the concentration of
ammonia to increase the level of efficiency, apart from through the separation of
the vapor phase from the liquid phase after the heat transfer from the external
heat source into the ammonia concentrations which are different in the two
phases.



The temperature of the first partly vaporized working medium flow 15 before
entry into the heat exchanger HE4 is 53.52°C and is thus the same temperature
as after leaving the heat exchanger HE2. The electrical power which can be
generated under these conditions with the aid of the turbine 2 amounts to 4033
Kw.
The pressure of the vapor phase 10 before entry into the turbine 2 amounts to
22.3 bar and the pressure of the expanded, vapor phase 11 on exit from the
turbine 2 amounts to 7.158 bar. The selected inlet pressure of 22.3 bar and the
pressure ratio of approx. 3.1 between the pressure of the vapor phase before
and after the turbine 2 enables a conventional single-stage high-efficiency
turbine to be used as turbine 2, with the associated cost and efficiency level
benefits.
Figure 3 by contrast shows the circuit of a device 30 known in the prior art as
KCS 34 (Kalina Cycle System 34) for executing a thermodynamic cycle process.
For better comparison of the known device 30 with the inventive device shown in
Figure 1, components and flows which correspond to each other are identified by
the same reference symbols. Device 30 differs from the inventive device shown
in Figure 1 in having an additional, heat exchanger HE3 connected on the
primary side between heat exchanger HE2 and heat exchanger HE4 and on the
secondary side between separator 4 and mixer 5. With the aid of heat exchanger

HE2 the pressurized, liquid working medium flow 14 is heated up by part
condensation of the expanded working medium flow 12 and a heated (liquid)
working medium flow 15 created. The heated working medium flow 15 is
subsequently further heated by means of the heat exchanger HE3 by cooling
down of the liquid phase 19 and thereby a further heated working medium flow
15a created.
Figure 4 shows a cycle calculation for a device known from the prior art which
essentially corresponds to the device 30 shown in Figure 3 and has additionally
only been supplemented by a number of valves 27. The initial conditions
assumed for the calculations were an ammonia concentration in the water of
89.2% and - as in the case of the cycle calculation of Figure 2 - a thermal water
flow 20 with a temperature of 120°C as well as a mass flow of 141.8 kg/s. The
temperature of cooling water flow 25 is 9.4°C.



The electrical power that can be generated in this case amounts to only 3818
kW. The obtainable electrical power is thus higher in the case of the inventive
cycle according to Figure 1 and 2 by 5.6% than in the case of the cycle process
known from the prior art.
The heated working medium flow 15 which leaves heat exchanger HE2 at a
temperature of 39°C is further heated up in heat exchanger HE3 through cooling
down of the liquid phase 19 to 48.87°C and fed as working medium flow 15a to
heat exchanger HE4.
Whereas in the known case the temperature of the discharged thermal water 22
is still 70.46°C, in the case of the inventive cycle process as shown in Figure 2
the discharged thermal water 22 only has a temperature of 57.45°C. In the case
of the inventive cycle process comparatively more energy can thus be extracted
from the thermal water.
As a result of the pressure of the vapor phase 10 at the input of the turbine 2 of
32.41 bar and of the pressure ratio of 4.8 between the pressure of the vapor
phase at the input of the turbine 2 and the pressure of the expanded vapor
phase 11 at the output of the turbine, a conventional single-stage turbine cannot

be used in the case of the cycle shown in Figure 4. Either two conventional
single-state turbines connected in series must two conventional single-stage
turbines connected in series must then be used, or a single turbine specifically
suitable for high pressures and pressure ratios greater than 4 must be used
which in both cases is associated with higher costs and with efficiency losses
compared to a single conventional turbine.
The increased heating surface requirement of 28.5% also resulting from the
increased heat exchanger power results in a greater need for investment. These
increased costs can however be compensated for in a large part by the simplified
pipework and the omission of heat exchanger HE3, so that the plant costs overall
remain essentially the same.
The invention has been described above with reference to preferred exemplary
embodiments, but can generally be seen as not being restricted to these
exemplary embodiments. Instead there is the option of a plurality of variations
and modifications of the invention or of these exemplary embodiments. For
example - as also occurs in the typical circuit shown in Figure 2 - additional
valves can be connected into the circuit.

WE CLAIM :
1. A method for executing a thermodynamic cycle process, comprising
the steps of:
- pumping a flow of liquid working medium (13) at an increased pressure
and forming a pressurized, liquid working medium flow (14);
- heating up and partially vaporizing the pressurized liquid working medium
flow (14) by part condensation of an expanded working medium flow (12)
and creating a first partly vaporized working medium flow (15) and a
partly condensed, expanded working medium flow (12a);
- further vaporizing the partly vaporized working medium flow (15) with
heat which is transferred from an external heat source (20), and creating
a second at least partly vaporized working medium flow (18); and
- separating a liquid phase (19) from a vapor phase (10) of the second at
least partly vaporized working medium flow (18);
- expanding the vapor phase (10), converting its energy into a usable form
and creating an expanded vapor phase (11);
- mixing the liquid phase (19) with the expanded vapor phase (11) and
forming the expanded working medium flow (12); and

- completely condensing the partly condensed, expanded working medium
flow (12a) and creating the liquid working medium flow (13).
2. The method as claimed in claim 1, wherein the pressure of the vapor
phase (10) is less than 24 bar.
3. The method as claimed in claim 1 or 2, wherein the pressure of the
vapor phase (10) is three to four times of the pressure of the
expanded vapor phase.
4. The method as claimed in one of the preceding claims, wherein a
multi-substance mixture is used as the working medium.
5. The method as claimed in claim 4, wherein a two-substance mixture,
in particular an ammonia-water mixture, is used as the multi-substance
mixture.
6. The method as claimed in one of the preceding claims, wherein a
geothermal liquid, in particular thermal water, is used as the external
heat source (20).
7. The method as claimed in one of the preceding claims, wherein the
heat source (20) is enabled to provide a temperature of 100°C to
140°C.
8. A device for executing a thermodynamic cycle process, in particular for
executing the method as claimed in one of the preceding claims,
comprising :

- a pump (3) for pumping a flow of liquid working medium (13) at an
increased pressure and creating a pressurized liquid working medium flow
(14);
- a first heat exchanger (HE2) for creating a first partly vaporized working
medium flow (15) by heating up and part vaporization of the pressurized
liquid working medium flow (14) through part condensation of an
expanded working medium flow (12);
- a second heat exchanger (HE4) for creating a second at least partly
vaporized working medium flow (18) through further vaporization of the
first partly vaporized working medium flow (15) with heat which is
transferred from an external heat source (20);
- a separator for separation of a liquid phase (19) from a vapor phase (10)
of the second at least partly vaporized working medium flow (18);
- means (2), in particular a turbine, for expanding the vapor phase (10),
converting its energy into a usable form and creating an expanded vapor
phase (11);
- a mixer (5) for mixing the liquid phase with the expanded vapor phase
and creating an expanded working medium flow (12);
- a third heat exchanger (HE1) for completely condensing the partly
condensed, expanded working medium flow (12a) and creating the liquid
working medium flow (13).

9. The device as claimed in claim 8, wherein the pressure of the vapor
phase (10) is less than 24 bar.
10. The device as claimed in one of the claims 8 or 9, wherein the
pressure of the vapor phase (10) is three to four times of t he pressure
of the expanded vapor phase (11).
11. The device as claimed in one of the claims 8 to 10, wherein the
working medium consisting of a multi-substance mixture.
12. The device as claimed in claim 11, wherein the multi-substance
mixture is a two-substance mixture, in particular an ammonia-water
mixture.
13. The device as claimed in one of the claims 8 to 12, wherein a
geothermal liquid, in particular thermal water is used as the external
heat source (20).
14. The device as claimed in one of the claims 8 to 13, wherein the
external heat source (20) is enabled to provide a temperature of 100°C
to 140°C.


The invention relates to an disclose a method for executing a thermodynamic
cycle process. To this end, the pressure of a liquid working substance flow (13)
is increased and a first partially evaporated working substance flow (15) is
produced by the partial condensation of a working substance flow (12) with a
low surface tension. Further evaporation of the first partially evaporated working
substance flow (15) with heat transmitted by an external heat source (20)
produces a second at least partially evaporated working substance flow (18). In
said second at least partially evaporated working substance flow (18), the
vaporous phase (10) is separated from the liquid phase, the energy of the
vaporous phase (10) is converted into a usable form, and a vaporous phase (11)
with a low surface tension is combined with the liquid phase (19) in such a way
as to form the working substance flow (12) with a low surface tension. The liquid
working substance flow (13) is, in turn, obtained by complete condensation of
the partially condensed working substance flow (12a) with a low surface tension.

Documents:

02964-kolnp-2006-abstract.pdf

02964-kolnp-2006-assignment.pdf

02964-kolnp-2006-claims.pdf

02964-kolnp-2006-correspondence others.pdf

02964-kolnp-2006-description (complete).pdf

02964-kolnp-2006-drawings.pdf

02964-kolnp-2006-form1.pdf

02964-kolnp-2006-form2.pdf

02964-kolnp-2006-form3.pdf

02964-kolnp-2006-form5.pdf

02964-kolnp-2006-international publication.pdf

02964-kolnp-2006-international search authority report.pdf

02964-kolnp-2006-other document.pdf

02964-kolnp-2006-pct form.pdf

2964-KOLNP-2006-ABSTRACT 1.1.pdf

2964-KOLNP-2006-AMANDED CLAIMS.pdf

2964-KOLNP-2006-CORRESPONDENCE 1.1.pdf

2964-kolnp-2006-correspondence others-1.1.pdf

2964-kolnp-2006-correspondence.pdf

2964-KOLNP-2006-DESCRIPTION (COMPLETE) 1.1.pdf

2964-KOLNP-2006-DRAWINGS 1.1.pdf

2964-KOLNP-2006-EXAMINATION REPORT REPLY RECIEVED.pdf

2964-kolnp-2006-examination report.pdf

2964-KOLNP-2006-FORM 1-1.1.pdf

2964-kolnp-2006-form 18.pdf

2964-KOLNP-2006-FORM 2-1.1.pdf

2964-KOLNP-2006-FORM 3-1.1.pdf

2964-kolnp-2006-form 3.pdf

2964-kolnp-2006-form 5.pdf

2964-KOLNP-2006-FORM-27.pdf

2964-kolnp-2006-gpa.pdf

2964-kolnp-2006-granted-abstract.pdf

2964-kolnp-2006-granted-claims.pdf

2964-kolnp-2006-granted-description (complete).pdf

2964-kolnp-2006-granted-drawings.pdf

2964-kolnp-2006-granted-form 1.pdf

2964-kolnp-2006-granted-form 2.pdf

2964-KOLNP-2006-GRANTED-LETTER PATENT.pdf

2964-kolnp-2006-granted-specification.pdf

2964-KOLNP-2006-OTHERS.pdf

2964-kolnp-2006-others1.1.pdf

2964-KOLNP-2006-PA.pdf

2964-kolnp-2006-priority document.pdf

2964-kolnp-2006-reply to examination report.pdf

2964-kolnp-2006-translated copy of priority document.pdf

abstract-02964-kolnp-2006.jpg


Patent Number 248327
Indian Patent Application Number 2964/KOLNP/2006
PG Journal Number 27/2011
Publication Date 08-Jul-2011
Grant Date 05-Jul-2011
Date of Filing 13-Oct-2006
Name of Patentee SIEMENS AKTIENGESELLSCHAFT
Applicant Address WITTELSBACHERPLATZ 2, 80333 MUNCHEN
Inventors:
# Inventor's Name Inventor's Address
1 LENGERT JORG SCHAWALBENSTR.6,91475 LONNERSTADT-AILSBACH
PCT International Classification Number F01K 25/06
PCT International Application Number PCT/EP2005/051617
PCT International Filing date 2005-04-13
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102004018627.8 2004-04-16 Germany