US4083189A
Expired / Lapsed
US
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Open cycle method and apparatus for generating energy from ocean thermal gradients
Assignee: Carnegie Mellon University
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Filing: 1977-03-17
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Granted: 1978-04-11
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Expires: 1997-03-17
Abstract
Abstract Power is generated by subjecting a body of water in an evacuated chamber alternately to pressure corresponding to the vapor pressure of water at the surface of a body of water, such as tropical sea water, and pressure corresponding to the vapor pressure of subsurface water. The body of water falls and rises in correspondence with the changing pressures and the pressures are alternated in synchronism with the natural period of oscillation of the body of water so as to increase the amplitude of its oscillation. Power is withdrawn from the oscillating body of water either by feeding overflow water to water turbines or by anemometer type turbines within the chamber. Apparatus details are disclosed.
Inventors
- 👤 John G. Fetkovich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:13
CPC Classifications
F; F03; F03G; F03G7/00; F03G7/04; F03G7/05; Y; Y02; Y02E; Y02E10/00; Y02E10/30
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
143 words
Apparatus for generating energy from the thermal gradient in a body of water comprising a closed-top evacuated chamber partially immersed in the water and extending above the water level therein, first valved means connecting the closed portion of the chamber with a source of water vapor at a pressure corresponding to the surface temperature of the body of water, second valved means connecting the closed portion of the chamber with a source of water vapor at a pressure corresponding to the subsurface temperature of the body of water, means for repeatedly opening and closing the first valve and simultaneously closing and opening, respectively, the second valve, in synchronism with the natural frequency of oscillation of the water in the chamber so as to cause oscillation of the water in the chamber, and means for extracting energy from the oscillating water in the chamber.
Claim 2
Dependent Claim
143 words
Apparatus for generating energy from the thermal gradient in a body of water comprising a closed-top evacuated chamber partially immersed in the water and extending above the water level therein, first valved means connecting the closed portion of the chamber with a source of water vapor at a pressure corresponding to the surface temperature of the body of water, second valved means connecting the closed portion of the chamber with a source of water vapor at a pressure corresponding to the subsurface temperature of the body of water, means for repeatedly opening and closing the first valve and simultaneously closing and opening, respectively, the second valve, in synchronism with the natural frequency of oscillation of the water in the chamber so as to cause oscillation of the water in the chamber, and means for extracting energy from the oscillating water in the chamber.
Claim 3
Dependent Claim
42 words
The apparatus of claim 1 in which the means for extracting energy comprise overflow collecting means positioned around the closed-top chamber so as to collect overflow of water at the upper extreme of its oscillation, and turbine means driven by that overflow.
Claim 4
Dependent Claim
31 words
The apparatus of claim 1 in which the means for extracting energy comprise anemometer-like means positioned inside the closed chamber so as to be rotated by the oscillating column of water.
Claim 5
Dependent Claim
19 words
The apparatus of claim 1 in which the closed top chamber is a columnar chamber open at the bottom.
Claim 6
Dependent Claim
12 words
Apparatus of claim 1 in which the closed top chamber is U-shaped.
Claim 7
Dependent Claim
24 words
Apparatus of claim 1 in which the closed top chamber comprises a central closed-top open-bottom portion positioned in and surrounded by a closed-bottom portion.
Claim 8
Dependent Claim
21 words
Apparatus of claim 1 in which the closed-top chamber is divided by a vertical partition stopping short of its closed bottom.
Claim 9
Dependent Claim
94 words
Apparatus of claim 1 in which the source of water vapor at a pressure corresponding to the surface temperature of a body of water comprises a closed compartment, means connecting that compartment with surface water, means for pumping that compartment to reduce the water level therein below the level corresponding to the surface water temperature, and spray nozzle means positioned in the closed compartment and connected with the surface water, whereby surface water is sucked into the closed compartment by the partial vacuum within that compartment and is vaporized therein by the spray nozzles.
Claim 10
Dependent Claim
93 words
Apparatus of claim 1 in which the source of water vapor at a pressure corresponding to the subsurface temperature of the body of water comprises a closed compartment, means connecting that compartment with subsurface water, means for pumping that compartment to reduce the water level therein below the level corresponding to the subsurface water temperature, and spray nozzle means positioned in the closed compartment and connected with the subsurface water whereby subsurface water is sucked into the closed compartment by the partial vacuum within that compartment and vaporized therein by the spray nozzles.
Claim 11
Independent Claim
116 words
The method of generating energy from thermal gradients in a body of water comprising maintaining a subatmospheric pressure over a confined volume of water, lowering that pressure to a value approximating the vapor pressure of subsurface water, whereby the level of the confined volume of water tends to rise, raising the pressure over the confined volume of water to a value approximating the vapor pressure of surface water, whereby the level of the confined body of water tends to fall, repeatedly lowering and raising the pressure so as to cause the confined volume of water to oscillate, thereby increasing the distance between its upper and lower levels, and withdrawing energy from that oscillating body of water.
Claim 12
Independent Claim
116 words
The method of generating energy from thermal gradients in a body of water comprising maintaining a subatmospheric pressure over a confined volume of water, lowering that pressure to a value approximating the vapor pressure of subsurface water, whereby the level of the confined volume of water tends to rise, raising the pressure over the confined volume of water to a value approximating the vapor pressure of surface water, whereby the level of the confined body of water tends to fall, repeatedly lowering and raising the pressure so as to cause the confined volume of water to oscillate, thereby increasing the distance between its upper and lower levels, and withdrawing energy from that oscillating body of water.
Claim 13
Dependent Claim
44 words
The method of claim 10 in which the pressure over the confined volume of water is raised and lowered in synchronism with the natural frequency of oscillation of the confined body of water, so as to produce sustained oscillation of the body of water.
Claim 14
Dependent Claim
33 words
The method of claim 10 in which the energy is withdrawn as potential energy by tapping off a fraction of the body of water while it is at its upper level of oscillation.
Claim 15
Dependent Claim
27 words
The method of claim 10 in which the energy is withdrawn as kinetic energy by causing the oscillating body of water to drive rotating means positioned therein.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-10 | 1981-10-10 | 1982-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-10 | 1985-10-10 | 1986-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-10 | 1989-10-10 | 1990-04-11 | $7700.00 | Window Closed / Lapsed |