Apparatus for underwater environmental energy transfer with a long lead zirconate titanate transducer

• US 8,274,167 B1
• Filed: 01/07/2010
• Issued: 09/25/2012
• Est. Priority Date: 01/07/2010
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Hughes, Derke R.
• Primary Examiner(s): Patel, Tulsidas C
• Assistant Examiner(s): Nguyen, Viet
• Application Number:
  US12/683,503
• Time in Patent Office: 992 Days
• Field of Search: 290/43, 290/42, 290/53, 290/54, 290/1.R, 60495-502, 605/05, 417330-333
• US Class Current: 290/42
• CPC Class Codes: F03B 13/1885 and the wom is tied to the rem
• CPC Class Codes: F05B 2220/709 Piezoelectric means
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

The invention as disclosed is an underwater based electric energy production system. A cable having a piezoelectric core is attached on one end thereof to a floating buoy and on the other end thereof to an anchor. The system is deployed in the water such that the cable extends vertically through a water column. Movement of the cable due to water current generates electric power that can be harvested and stored. The floating buoy can be at or near the water'"'"'s surface and the anchor can but need not rest on the sea floor.

Claims

1. An underwater electric energy production system comprising:

a buoy, wherein said buoy is situated on a surface of a large body of water so as to float on the surface;

a cable capable of surrounding a core, said cable having a first end and a second end, wherein the first end of said cable is joined to said buoy;

a lead zirconate titanate core surrounded by said cable, wherein said lead zirconate titanate core functions as a piezoelectric transducer capable of generating electricity from vibrations from underwater currents;

an anchor joined to said second end of said cable submerged in the large body of water, wherein said anchor is used to keep the tension on the lead zirconate titanate core within the cable, such that a fixed string configuration embodies a mathematical representation for the cable wherein the strain on the cable is expressed as S=s^ET+dE and the charge density is expressed as D=dT+e^TE, wherein the vertical configuration is adjustable to generate a variety of levels of energy because the draft on the anchor and buoy can be regulated to produce different amounts of tension on the cable, wherein the coupling efficiency of the mechanical to electrical energy conversion for the vibrating lead zirconate titanate core is expressed as

2. The system of claim 1 wherein the total energy computation of the system is directly related to a tension on said cable, a cross-sectional area of said core, a current speed of the large body of water, and wave periodicity of the large body of water to describe the amount of power potentially available from the underwater electric energy production system.

3. The system of claim 1 wherein said cable surrounding said lead zirconate titanate core is between 10 meters and 300 meters long.

4. The system of claim 1 wherein said cable is a reinforced armored tow cable.

5. The system of claim 1 further comprising a velocity sensor joined to the cable and microprocessor wherein the velocity sensor can measure the velocity of the water current of the large body of water.

6. The system of claim 1 further comprising a strain sensor joined to the cable and microprocessor wherein the strain sensor can measure the tension on the cable.

7. The system of claim 1 further comprising:

a reservoir tank located in the anchor capable of holding water; and

a valve joined to the reservoir tank that will allow water into the reservoir tank, wherein actuation of the valve is controlled by the microprocessor.

8. The system of claim 1 wherein the battery that captures the electric current is a nickel cadmium battery.

9. The system of claim 7 further comprising a sensor suite joined to the nickel cadmium battery.

10. The system of claim 8 further comprising a 900 MHz radio joined to said nickel cadmium battery and to said microprocessor wherein said radio can transmit information gathered by the sensor suite.