California Energy Commission (CEC)

ENERGY INNOVATIONS SMALL GRANT (EISG) PROGRAM

 

Project Summary

Build and Test a 3 KW Prototype of a Co-Axial, Multi-Rotor Wind Turbine

Douglas Selsam, Principal Investigator

 

Purpose:  To prove the co-axial, multi-rotor wind turbine technology as disclosed by the inventor, Douglas Spriggs Selsam, in U.S. Pat. Application numbers 09/881511, filed 06/14/01 and 09/997499, filed 11/23/01, and the Patent Cooperation Treaty (PCT) filing of June 14, 2002, by building and testing a reliable prototype, in a 3-kilowatt size. 

 

Proposed effort for this project: Build a three kilowatt prototype that is durable enough for 6 months of continuous testing, then field test the prototype for 6 months of power generation:

1.      We will first develop and build a prototype in a size of 3 kilowatts.  This work will be carried out by the principal investigator, Douglas Selsam.  The parts will be obtained from various manufacturers, and assembled by the principal investigator.

2.      We will carry out initial testing at the facilities of Windtesting.com in Tehachapi, CA, in conjunction with Brent Scheibel, and make any adjustments deemed necessary for long term testing.

3.      We will then subject this prototype to six months of long-term testing.  The testing will be carried out by Brent Scheibel at his WindTesting.com test range in Tehachapi, CA.  Brent Scheibel is a world recognized expert in the field of wind power.  He has headed the Anemometry Department at General Electric Wind Energy for North and South America, and has many years of experience erecting towers, acquiring and recording power measurement data, and conducting anemometry calibrations and comparative tests of wind turbines. His test range in Tehachapi is fully equipped with towers, electrical cables, banks of batteries, testing and recording equipment.  Brent has agreed to subject a prototype to six months of testing, and will measure power output at various wind speeds (power curve), long-term energy output, and overall behavior and reliability.  Brent will then provide a report on his findings.  Power and energy production data will be generated in spreadsheet form and in graphical form as scatter plots and power curves.

4.       We will determine how the behavior of this prototype compares to existing turbines of a similar diameter and turbines of a similar power rating, on the basis of cost and performance, and determine whether it looks promising to construct still larger prototypes.  This research will pave the way for more advanced turbines utilizing this new co-axial, multi-rotor technology.

 

Current single-rotor wind turbines are a refined version of a 1000-year-old design.  These wind turbines suffer from the following problems, challenges, and drawbacks:

1.      Inordinately heavy rotor weight since larger rotors become disproportionately heavy.  As blade length is increased, power generated per unit blade mass declines.

2.      Inordinately slow blade rotation since larger rotors turn more slowly; A gearbox, or special low-speed generator is required, since a conventional generator needs to turn faster.

3.      Not well-suited to areas with moderate wind resources: Single rotor turbines do not capture enough energy in class 4 wind regimes to be economical.

 

Our Multi-Rotor technology neatly solves all of these classic problems in wind turbine design.   Several small prototypes have now been tested, generating up to 1400 watts.  Progress to date may be seen at  http://www.selsam.com.

Our new design, now proven in small models, combines the power of multiple smaller rotors mounted to a single elongate driveshaft, to give the same power as a single larger rotor, with less cost, weight, and complexity.  Smaller rotors weigh less for the swept area, and turn faster, thereby delivering the same power at less torque, dispensing of the need for a gearbox, or special low-speed generator.  Our new design is self-aiming, requiring no dedicated apparatus to achieve this.  We expect to validate this revolutionary California design as being able to harvest more wind energy at less cost than current models, which use only a single rotor.

 

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