US4484446A
Expired / Lapsed
US
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Variable pressure power cycle and control system
Assignee: WK TECHNOLOGY Inc
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Filing: 1983-02-28
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Granted: 1984-11-27
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Expires: 2003-02-28
Abstract
Abstract A variable pressure power cycle and control system that is adjustable to a variable heat source is disclosed. The power cycle adjusts itself to the heat source so that a minimal temperature difference is maintained between the heat source fluid and the power cycle working fluid, thereby substantially matching the thermodynamic envelope of the power cycle to the thermodynamic envelope of the heat source. Adjustments are made by sensing the inlet temperature of the heat source fluid and then setting a superheated vapor temperature and pressure to achieve a minimum temperature difference between the heat source fluid and the working fluid.
Inventors
- 👤 Fred L. Goldsberry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:55
CPC Classifications
F; F01; F01K; F01K13/00; F01K13/02; F22; F22B; F22B35/00; F22B35/007
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
91 words
A method of generating power using a Rankine cycle with a turbine, a working fluid, and including a heating phase within a variable thermodynamic envelope that substantially fills a thermodynamic envelope defined by a variable temperature heat source fluid and a heat sink, comprising adjusting the temperature and pressure of the working fluid at the turbine inlet in response to changes in the inlet temperature of the heat source to maintain a minimum temperature difference between the heat source fluid and the working fluid during the heating phase of the cycle.
Claim 2
Independent Claim
91 words
A method of generating power using a Rankine cycle with a turbine, a working fluid, and including a heating phase within a variable thermodynamic envelope that substantially fills a thermodynamic envelope defined by a variable temperature heat source fluid and a heat sink, comprising adjusting the temperature and pressure of the working fluid at the turbine inlet in response to changes in the inlet temperature of the heat source to maintain a minimum temperature difference between the heat source fluid and the working fluid during the heating phase of the cycle.
Claim 3
Dependent Claim
26 words
The method of claim 1, wherein the Rankine cycle comprises a supercritical Rankine cycle and the variable heat source fluid comprises a liquid phase heat source.
Claim 4
Dependent Claim
22 words
The method of claim 2, wherein the heat source liquid comprises a geopressure-geothermal brine and the working fluid comprises a paraffinic hydrocarbon.
Claim 5
Dependent Claim
21 words
The method of claim 3 wherein: a. the turbine comprises a radial inflow turbine; and b. the working fluid comprises propane.
Claim 6
Independent Claim
178 words
A method of controlling a variable pressure supercritical Rankine power cycle utilizing a turbine, a condenser, a feed pump and a working fluid and including a heating phase comprising the steps of: a. sensing the inlet temperature of a heat source liquid; b. based on the heat source liquid inlet temperature and the working fluid and turbine utilized, selecting a superheated vapor point for the working fluid defining an isobaric pressure curve for the working fluid over the heating phase of the cycle, the isobaric pressure curve having a temperature substantially approaching the temperature of the heat source liquid at a point along the heating phase of the cycle; c. setting the back pressure immediately upstream of the turbine inlet to the pressure selected for the superheated vapor point for the working fluid; d. sensing the temperature of the working fluid at the superheated vapor point; and e. regulating the flow rate of the working fluid through the heating phase of the cycle so that the temperature of the working fluid at the superheated vapor point is maintained.
Claim 7
Independent Claim
178 words
A method of controlling a variable pressure supercritical Rankine power cycle utilizing a turbine, a condenser, a feed pump and a working fluid and including a heating phase comprising the steps of: a. sensing the inlet temperature of a heat source liquid; b. based on the heat source liquid inlet temperature and the working fluid and turbine utilized, selecting a superheated vapor point for the working fluid defining an isobaric pressure curve for the working fluid over the heating phase of the cycle, the isobaric pressure curve having a temperature substantially approaching the temperature of the heat source liquid at a point along the heating phase of the cycle; c. setting the back pressure immediately upstream of the turbine inlet to the pressure selected for the superheated vapor point for the working fluid; d. sensing the temperature of the working fluid at the superheated vapor point; and e. regulating the flow rate of the working fluid through the heating phase of the cycle so that the temperature of the working fluid at the superheated vapor point is maintained.
Claim 8
Dependent Claim
50 words
The method of claim 5, further comprising the steps of: a. sensing the temperature and pressure in the condenser, the condenser comprising a floating pressure condenser; and b. calculating an expansion curve for the turbine based on the saturated vapor temperature and pressure for the existing condenser temperature and pressure.
Claim 9
Dependent Claim
56 words
The method of claim 5 or 6, further comprising the steps of: a. sensing the discharge temperature of the heat source liquid; b. determining whether the discharge temperature of the heat source liquid is rising over time; and c. reducing the flow rate of the heat source liquid if the discharge temperature is rising over time.
Claim 10
Dependent Claim
55 words
The method of claim 5 or 6, further comprising the steps of: a. sensing the discharge temperature of the heat source liquid; b. determining whether the discharge temperature of the heat source liquid is rising over time; and c. adding a parallel power cycle to the system if the discharge temperature is rising over time.
Claim 11
Dependent Claim
93 words
The method of claim 8, further comprising the steps of: a. sensing the flow rate of the working fluid through the last parallel power cycle added to the system; b. comparing the measured flow rate of the working fluid to a predetermined minimum flow rate required for economical operation of the last parallel power cycle; and c. removing the last parallel power cycle from the system if the measured flow rate of the working fluid is less than the predetermined minimum flow rate required for economical operation of the last parallel power cycle.
Claim 12
Independent Claim
185 words
An apparatus for controlling a variable pressure supercritical Rankine power cycle utilizing a turbine, a condenser, a feed pump, and a working fluid and including a heating phase comprising: a. means for sensing the inlet temperature of the heat source liquid; b. means for selecting a superheated vapor point for the working fluid based on the heat source liquid inlet temperature and the working fluid and turbine utilized, the superheated vapor point defining an isobaric pressure curve for the working fluid over the heating phase of the cycle having a temperature substantially approaching the temperature of the heat source liquid at a point along the heating phase of the cycle; c. means for setting the back pressure immediately upstream of the turbine inlet to the pressure selected for the superheated vapor point for the working fluid; d. means for sensing the temperature of the working fluid at the superheated vapor point; and e. means for regulating the flow rate of the working fluid through the heating phase of the cycle so that the temperature of the working fluid at the superheated vapor point is maintained.
Claim 13
Independent Claim
185 words
An apparatus for controlling a variable pressure supercritical Rankine power cycle utilizing a turbine, a condenser, a feed pump, and a working fluid and including a heating phase comprising: a. means for sensing the inlet temperature of the heat source liquid; b. means for selecting a superheated vapor point for the working fluid based on the heat source liquid inlet temperature and the working fluid and turbine utilized, the superheated vapor point defining an isobaric pressure curve for the working fluid over the heating phase of the cycle having a temperature substantially approaching the temperature of the heat source liquid at a point along the heating phase of the cycle; c. means for setting the back pressure immediately upstream of the turbine inlet to the pressure selected for the superheated vapor point for the working fluid; d. means for sensing the temperature of the working fluid at the superheated vapor point; and e. means for regulating the flow rate of the working fluid through the heating phase of the cycle so that the temperature of the working fluid at the superheated vapor point is maintained.
Claim 14
Dependent Claim
51 words
The apparatus of claim 10, further comprising: a. means for sensing the temperature and pressure in the condenser, the condenser comprising a floating pressure condenser; and b. means for calculating an expansion curve for the turbine based on the saturated vapor temperature and pressure for the existing condenser temperature and pressure.
Claim 15
Dependent Claim
34 words
The apparatus of claim 10 wherein: a. the back pressure setting means comprises a back pressure valve; and b. the flow rate regulating means comprises a temperature control valve downstream of the feed pump.
Claim 16
Dependent Claim
34 words
The apparatus of claim 11 wherein: a. the back pressure setting means comprises a back pressure valve; and b. the flow rate regulating means comprises a temperature control valve downstream of the feed pump.
Claim 17
Dependent Claim
24 words
The apparatus of claim 10 wherein: a. the working fluid comprises a paraffinic hydrocarbon; and b. the heat source liquid comprises a geopressure-geothermal brine.
Claim 18
Dependent Claim
24 words
The apparatus of claim 11 wherein: a. the working fluid comprises a paraffinic hydrocarbon; and b. the heat source liquid comprises a geopressure-geothermal brine.
Claim 19
Dependent Claim
24 words
The apparatus of claim 12 wherein: a. the working fluid comprises a paraffinic hydrocarbon; and b. the heat source liquid comprises a geopressure-geothermal brine.
Claim 20
Dependent Claim
24 words
The apparatus of claim 13 wherein: a. the working fluid comprises a paraffinic hydrocarbon; and b. the heat source liquid comprises a geopressure-geothermal brine.
Claim 21
Dependent Claim
24 words
The apparatus of claim 10 wherein: a. the heat source liquid comprises an industrial product; and b. the working fluid comprises the industrial product.
Claim 22
Dependent Claim
24 words
The apparatus of claim 11 wherein: a. the heat source liquid comprises an industrial product; and b. the working fluid comprises the industrial product.
Claim 23
Dependent Claim
24 words
The apparatus of claim 12 wherein: a. the heat source liquid comprises an industrial product; and b. the working fluid comprises the industrial product.
Claim 24
Dependent Claim
24 words
The apparatus of claim 13 wherein: a. the heat source liquid comprises an industrial product; and b. the working fluid comprises the industrial product.
Claim 25
Dependent Claim
69 words
The apparatus of claim 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, further comprising: a. means for sensing the discharge temperature of the heat source liquid; b. means for determining whether the discharge temperature of the heat source liquid is rising over time; and c. means for reducing the flow rate of the heat source liquid if the discharge temperature is rising over time.
Claim 26
Dependent Claim
68 words
The apparatus of claim 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, further comprising: a. means for sensing the discharge temperature of the heat source liquid; b. means for determining whether the discharge temperature of the heat source liquid is rising over time; and c. means for adding a parallel power cycle to the system if the discharge temperature is rising over time.
Claim 27
Dependent Claim
96 words
The method of claim 23, further comprising: a. means for sensing the flow rate of the working fluid through the last parallel power cycle added to the system; b. means for comparing the measured flow rate of the working fluid to a predetermined minimum flow rate required for economical operation of the last parallel power cycle; and c. means for removing the last parallel power cycle from the system if the measured flow rate of the working fluid is less than the predetermined minimum flow rate required for economical operation of the last parallel power cycle.
Claim 28
Independent Claim
139 words
A method of converting heat from a variable liquid heat source to mechanical energy using a turbine, a condenser, a pump, a heat exchanger, and a working fluid to generate a supercritical Rankine cycle, the method comprising: a. selecting a working fluid having a critical temperature less than the temperature of the heat source liquid; b. vaporizing the working fluid isobarically by passing the working fluid in heat exchange with the liquid heat source at a supercritical pressure which maintains the working fluid at a preselected minimum temperature differential below the temperature of the heat source liquid during heat exchange; c. expanding the vaporized working fluid to generate mechanical energy; d. condensing and cooling the expanded working fluid; e. raising the pressure of the condensed and cooled working fluid; and f. repeating the cycle of steps (b) through (e).
Claim 29
Independent Claim
139 words
A method of converting heat from a variable liquid heat source to mechanical energy using a turbine, a condenser, a pump, a heat exchanger, and a working fluid to generate a supercritical Rankine cycle, the method comprising: a. selecting a working fluid having a critical temperature less than the temperature of the heat source liquid; b. vaporizing the working fluid isobarically by passing the working fluid in heat exchange with the liquid heat source at a supercritical pressure which maintains the working fluid at a preselected minimum temperature differential below the temperature of the heat source liquid during heat exchange; c. expanding the vaporized working fluid to generate mechanical energy; d. condensing and cooling the expanded working fluid; e. raising the pressure of the condensed and cooled working fluid; and f. repeating the cycle of steps (b) through (e).
Claim 30
Dependent Claim
45 words
The method of claim 25, wherein the minimum temperature differential is maintained by: a. controlling the pressure of the vaporized working fluid in response to changes in the temperature of the heat source liquid; and b. controlling the rate of flow of the working fluid.
Claim 31
Dependent Claim
30 words
A method as defined in claim 25 in which the heat source liquid has a given temperature between about 240° F. and 360° F., and the working fluid comprises propane.
Claim 32
Dependent Claim
30 words
A method as defined in claim 25 in which the heat source liquid has a given temperature between about 360° F. and 410° F., and the working fluid comprises isobutane.
Claim 33
Dependent Claim
30 words
A method as defined in claim 25 in which the heat source liquid has a given temperature between about 410° F. and 520° F., and the working fluid comprises pentane.
References Cited (Backward Citations)
US4242870A
Cited
US4358930A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |