Title of Invention

"ORGANIC RANKINE CYCLE FLUID"

Abstract A method of operating an organic rankinc cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert il to vapor. The vapor is then passed through a turbine, wiih the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid. The refrigerant is one of CFsCF;C(O)CF(CF;)2, (CF3)2 CFC(0)CF(CF3)2, CF~(CF2)2C(O)CF(CF3)2. CF3(CF2)3C(OK:F(CG3)2, CF3(CF2)5C(O)CF3, CF3CF-C(O)CF2CF2CF3, CFjC(0)CF(CF3)2.
Full Text Organic Rankine Cycle Fluid
Background of the Invention
[0001] This invention relates generally to organic rankine cycle systems and,
more particularly, to the use of an improved working fluid in such systems.
[0002] The well known closed rankine cycle comprises a boiler or
evaporator for the evaporation of a motive fluid, a turbine fed with vapor from the boiler to drive the generator or other load, a condenser for condensing the exhaust vapors from the turbine and a means, such as a pump, for recycling the condensed fluid to the boiler. Such a system as is shown and described in U.S. patent 3,393,515.
[0003] Such rankine cycle systems are commonly used for the purpose of
generating electrical power that is provided to a power distribution system, or grid, for residential and commercial use across the country. The motive fluid used in such systems is often water, with the turbine then being driven by steam. The source of heat to the boiler can be of any form of fossil fuel, e.g. oil, coal, natural gas or nuclear power. The turbines in such systems are designed to operate at relatively high pressures and high temperatures and are relatively expensive in their manufacture and use.
[0004] The Organic Rankine Cycle (ORC) is a vapor power cycle with
refrigerant (an organic fluid) instead of water/steam as the working fluid.
Functionally it resembles the steam cycle power plant: a pump increases the pressure
of condensed liquid refrigerant. This liquid is vaporized in an evaporator/boiler by
extracting waste heat from turbine or engine exhaust. The high-pressure refrigerant
vapor expands in a turbine, producing power. The low-pressure vapor leaving the
turbine is condensed before being sent back to the pump to restart the cycle.
[0005] For refrigerants with certain properties, commercially available air-
conditioning and refrigeration equipment with its proven reliability and performance
record can be used cost effectively in a power producing ORC system.
[0006] The rankine cycle used for power generation production goes through
the following four processes in this order:
1. Adiabatic pressure rise through a pump

2. Isobaric heat addition in a preheater, evaporator and
superheater
3. Adiabatic expansion in a turbine
4. Isobaric heat rejection in a condenser.
[0007] The main thermodynamic irreversibility in organic rankine cycles is
caused by the large temperature difference in the evaporator between the temperature of the waste heat stream and the boiling refrigerant. The higher the waste heat stream temperature is the larger this irreversibility becomes. Organic fluids that can boil at higher temperatures have the ability to reduce the temperature difference between the waste heat stream and the organic rankine cycle working fluid and will therefore result in higher thermodynamic ORC cycle efficiency. Fluids can boil at temperatures up to the critical temperature, above which there is no boiling. Consequently, fluids with higher critical temperatures will result in higher ORC cycle efficiency. Chlorine containing fluids with high critical temperatures have been proposed in the past as ORC fluids. For example, Rl 14, Rl 13, Rl 1, R141b and R123 have higher critical temperatures than R245fa and would result in substantially higher thermal efficiencies. However, these fluids are either flammable and/or toxic, ozone layer depleting and/or have substantial global warming impact. They have either been banned (the CFC's) or soon will be banned (the HCFC's) asd therefore will not be available for use in future ORC products.
Summary of the Invention
[0008] It is therefore an object of the present invention to overcome the
problems of the prior art described above.
[0009] It is a further object of the present invention to provide a new and
improved organic rankine cycle working fluid.
[0010] Another object of the present invention is the provision of an organic
rankine cycle working fluid that can operate at lower pressures and lower turbo
machinery speed.
[0011] Yet another object of the present invention is the provision of an
organic cycle working fluid having a high critical temperature that is also environmentally friendly.
[0012] Still another object fo the present invention is the provision for a
rankine cycle system which is economical, practical in use, and which is environmentally friendly.
[0013] It has been discovered that an organic fluid recently introduced into
the market place as a fire extinguishing fluid has unique applications as a working fluid or refrigerant in an organic rankine cycle system. One example of a preferred fluid is the ketone CF3CF2C(O)CF(CF3)2 which has a critical temperature higher than that of the most acceptable prior art fluid R245fa. This fluid has zero ozone layer potential and zero global warming potential, and is therefore environmentally friendly.
[0014] This fluid and equivalent ketones can be advantageously used in a
typical organic rankine cycle system such as where a pump is used to circulate liquid refrigerant to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing first through a plurality of nozzles and then through a turbine. The resulting cooled vapor is then passing through a condenser for condensing the vapor to a liquid. In the present invention the refrigerant can be any of CF3CF2C(O)CF(CF3)2, (CF3)2 CFC(O)CF(CF3)2, CF3(CF2)2C(O)CF(CF3)2, CF3(CF2)3C(0)CF(CG3)2, CF3(CF2)sC(O)CF3, CF3CF:C(0)CF2CF2CF3; CF3C(0)CF(CF3)2, perfluorocyclohexanone, and mixtures thereof.
Brief Description of the Drawing
[0015] For a further understanding of these and objects of the invention,
reference will be made to the following detailed description of the invention which
is to be read in connection with the accompanying drawing, wherein:
[0016] FIG. 1 is a schematic illustration of an organic rankine cycle system
in accordance with the present invention.
[0017] FIG. 2 are comparative TS diagrams for R245fa and
CF3CF2C(0)CF(CF3)2.
[0018] FIG. 3 illustrates an ORC with 245fa utilizing a 370°C sensible waste
heat source.
[0019] FIG. 4 illustrates an ORC with CF3CF2C(O)CF(CF3)2 utilizing a
370°C sensible waste heat source.
[0020] FIG. 5 is a schematic illustration of an organic rankine cycle system
illustrating a second embodiment of the present invention.
Detailed Description of the Invention
[0021] Referring to Fig. 1, a typical rankine cycle system 10 as shown
includes an evaporator/boiler 12 and a condenser 14 which, respectively, receives
and dispenses heat. These components perform similar functions in the vapor
compression cycle used in conventional air conditioning and refrigeration systems.
These heat exchanger components can therefore be used with minor modifications in
organic rankine cycle applications. The rankine cycle contains a power producing
turbine 16 which is driven by the motive fluid in the system and in turn drives a
generator 18 that produces power as well as power consuming pump 20 that
increases the pressure of the liquid leaving the condenser.
[0022] In operation, the evaporator which is commonly a boiler having a
significant heat input, vaporizes the motive fluid, which is the novel refrigerant of the present invention, with the vapor then passing to the turbine for providing motive power thereto. Upon leaving the turbine, the low pressure vapor passes to the condenser 18 where it is condensed by way of heat exchange relationship with a cooling medium. The condensed liquid is then circulated to the evaporator by a pump 22 as shown to complete the cycle.
[0023] Fig. 2 shows a comparative TS diagram for R245fa and
CF3CF2C(O)CF(CF3)2. Note the higher critical temperature for CF3CF2C(0)CF(CF3)2.
[0024] Fig. 3 shows the Organic Rankine Cycle with R245fa utilizing a
370°C sensible waste heat source (point A) being cooled down to 93 °C (point B).
The processes in the R245fa organic Rankine cycle include expansion of the
working fluid in a turbine and thus producing power going from state point 1 to 2.
Desuperheating (2->3) and condensing (3->4) in the condenser, thus rejecting to
ambient. Increasing the pressure with a pump (4->5) and preheating (5->6) and
evaporating (6->l) in the refrigerating boiler utilizing the waste heat that is being
cooled down from an inlet temperature A to an exit temperature B.
[0025] Fig. 4 shows an organic Rankine cycle with CF3CF2C(O)CF(CF3)2
utilizing the same waste heat stream. Due to the fact that the critical temperature of
CF3CF2C(O)CF(CF3)2 is higher than that of R245fa as shown in Fig. 1, the heat
transfer irreversibility - the area AB561A - is slightly larger for R245fa than for
CF3CF2C(O)CF(CF3)2. This results in a larger thermodynamic Rankine cycle
efficiency for CF3CF2C(0)CF(CF3)2 compared to R245fa.
[0026] The turbine exit temperature at state point 2 is higher for
CF3CF2C(O)CF(CF3)2 than for R245fa. This allows the replacement of part of the
condenser with a water heater and running the Organic Rankine cycle in a CHP
(combined heat and power) mode as shown in Fig. 5 In order to achieve the same
CHP function with R245fa, higher turbine inlet temperatures would be required
complicating the design and resulting in higher first cost.
[0027] While the present invention has been particularly shown and
described with reference to the preferred mode as illustrated in the drawing, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims.





We claim:
]. A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated (o an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid; wherein said refrigerant is CF3CF2C(O)CF(CF3)2.
2. A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid; wherein said refrigerant is selected from the group consisting of CF3CF3C(0)CF(CF3)2, (CFj)2 CFC(O)CF{CF3)3, CF?(CF2);C(0)CF(CI:.3):> CF3(CF2)3C(0)CF(CG3)2, CF3(CF2)SC(0}CF3. CF3CFzC(O)CF2CF2CF3, CF3C(0)CF(CF3)2.
3, A method of operating an organic rankine cycle system wherein a pump is used to circulate liquid refrigerant to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing first through a plurality of nozzles and then through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid, wherein the step of introducing heat to the refrigerant is by way of extracting waste heat from an engine and further wherein said refrigerant is CF3CF2C(O)CF(CF3):.
4. (Canceled)
5. A method as set forth in claim 13 wherein the step of extracting heal
from said internal combustion engine is accomplished by extracting heat from
exhaust gases leaving said internal combustion engine.

6. A method as set forth in claim 13 wherein the step of extracting heat
from the internal combustion engine is accomplished by extracting heat from coolant
flowing within the said combustion engine.
7. A method of operating an organic rankine cycle system wherein a
pump is used to circulate liquid refrigerant to an evaporator where heat is introduced
to the refrigerant to convert it to vapor, with the vapor then passing first through a
plurality of nozzles and then through a turbine, with the resulting cooled vapor ten
passing through a condenser for condensing the vapor to a liquid; wherein the step
of introducing heat lo the refrigerant is by way of extracting waste heat from an
engine and further wherein said refrigerant is at least one selected from the group
consisting of CF3CF2C(0)CF(CF3)2, (CF,)2CFC(0)CF(CF,)2,
CF3CCF2)2C(0)CF(CF3)2 CF3(CF2)3C(0)CF(CG32, CF,(CF2)sC(0)CF3,
C.F3CF2C(O)CF2CF2CF3, CF3C(0)CF(CF3)2, perfluorocyclohexanone, and mixtures
thereof.
8. A method as set forth in claim 7 wherein said engine is an internal
combustion engine.
9. (Canceled)
10 {Canceled)
11. A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the

vapor to a liquid; wherein said refrigerant is CF3CF2C(O)CF(CF3)2, and where said condenser further includes a water heater which utilizes waste heat from said turbine to generate hot water.
12. A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat extracted from an internal combustion engine is introduced to the refrigerant to convert it to vapor, with the vapor then passing through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid; wherein said refrigeranl is CF3CF2C(O)CF(CFj)2.
13. A melhod of operating an organic rankine cycle system wherein a liquid refrigerant is circulaled to an evaporator where heat extracted from an internal combustion engine is introduced to the refrigerant to convert it to vapor, with the vapor then passing through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid; wherein said refrigerant is selected from the group consisting of CF3CF2C(O)CF(CF3)2, (CF3)2 CFC(0)CF(CF3)2, CFj(CF2)2C(0)CF(CF3)2, CF3(CF2)3C(0)CF(CG3):.
«••-
'CF(CF2)5C(0)CFj, CF3:.CF2C(0)CF2CF2CF3, CF3C(0)CF(CF3)3j.

Documents:

4316-delnp-2006-Abstract-(12-10-2012).pdf

4316-delnp-2006-abstract.pdf

4316-delnp-2006-assignment.pdf

4316-delnp-2006-Claims-(12-10-2012).pdf

4316-delnp-2006-claims.pdf

4316-delnp-2006-Correspondence Others-(09-04-2012).pdf

4316-delnp-2006-Correspondence Others-(26-03-2012).pdf

4316-delnp-2006-Correspondence-Others-(12-10-2012).pdf

4316-delnp-2006-correspondence-others.pdf

4316-delnp-2006-description(complete).pdf

4316-delnp-2006-drawings.pdf

4316-delnp-2006-form-1.pdf

4316-delnp-2006-form-2.pdf

4316-delnp-2006-Form-3-(26-03-2012).pdf

4316-delnp-2006-form-3.pdf

4316-delnp-2006-form-5.pdf

4316-delnp-2006-GPA-(09-04-2012).pdf

4316-delnp-2006-pct-210.pdf

4316-delnp-2006-pct-304.pdf

4316-delnp-2006-Petition-137-(12-10-2012).pdf


Patent Number 256000
Indian Patent Application Number 4316/DELNP/2006
PG Journal Number 16/2013
Publication Date 19-Apr-2013
Grant Date 17-Apr-2013
Date of Filing 26-Jul-2006
Name of Patentee UNITED TECHNOLOGIES CORPORATION
Applicant Address ONE FINANCIAL PLAZA, HARTFORD, CT 06101 USA
Inventors:
# Inventor's Name Inventor's Address
1 JONSSON ULF J. 100 SALLY DRIVE, SOUTH WINDSOR CONNECTICUT 06074, USA
2 BRASZ JOOST J. 1 LANDGROVE DRIVE, FAYETTEVILLE, NY 13066 USA
PCT International Classification Number C09K 5/04
PCT International Application Number PCT/US2005/002086
PCT International Filing date 2005-01-25
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/771,012 2004-02-03 U.S.A.