hydraulics for wind power transfer

[Rustydad]

I would like some help with this idea. Some folks are trying to design a new concept in using wind power. It goes like this and any advise or criticism is helpful. Instead of coupling a wind turbine to a generator directly you would use the turbine to turn a hydraulic pump then move the fluid through a rotary coupling that allowed the horizontal movement of the turbine to follow the wind. The fluid would be piped to the ground where the hydraulic power would be transfered from a hydraulic motor to an induction generator driven directly and tied directly to the grid. The turbine needs to spin at about 500 to 800 rpm and the generator at 1800 rpm. Does this sound feasable using off the shelf hydraulics? Bob Hazard

 

[jdsewell]

What are the advantages of using hydraulics? it would seem to me the let of energy due to friction and the ineffeciencies in the pumps would be less advantages then mounting the generator directly to the turbine as in a conventional design. but i digress.

 

[butelja]

It sounds like it should be feasible, but as jdsewell has mentioned, the efficiency of the pump and hydraulic motor would have to be evaluated. If each were ~90% efficient, then the system would be <81% efficient due to additional minor (fluid friction, etc.) losses. A direct coupled gear drive could probably by >95% efficient.

The hydraulic concept could have the following advantages: 1.) Lighter weight, 2.) Easy control of max. torque by system relief valve setting, and 3.) Allow wind turbine RPM to vary with wind speed, and use fixed pitch. The generator RPM could be kept at synchronous speed by using a variable displacement (swashplate) hydraulic motor and closed loop control.