515Views14Replies

windmill on face of truck/bus ? Answered

The windmill on the car doesnt work as your adding more force in the opposite direction to the work done by the engine. What about using the frictional energy on the face of bigger vehicles like trucks and buses that exist already to run a small windmill. Probably charge a battery or use it effectively in some other way.
I cannot see a direct negative to this except finding the way i can place a turbine without increasing the opposing force and using as much of the existing one

Tags:

Discussions

Any energy you tap from the vehicle comes out of the vehicle's engine, directly or indirectly. In this case, it's extracted in the form of creating additional air resistance, forcing the engine to work harder to maintain the same vehicle speed.

well there is already a force acting on the face of the bus/truck right? this is a force that does nothing but hit the truck and provide air friction. What im thinking is instead of this just being a frictional force wasted we can tap the force to do some work by rotating a blade for example. Ofcourse this is being supplied by the engine but it existed before to overcome friction. Im just increasing efficiency by using it to our advantage

Anything you put in the airstream of this air getting pushed out of the way is going to impeed the movement of the air and it will take more force to move it out of the way.  As it takes more force to move it out of the way you will have to burn more gasoline.

The only way to generate electricity like this for free is to coast down a long hill using no gas.

so adding a rotating blade in place of a flat surface increases the force acting against the vehicle?
again my only concern is that when im already having a huge surface area will adding a rotating blade within it increase the force against it

All that air that is trying to get out of the way of the bus is being pushed by the bus, if you impeed it by any means, including a wind generator, you are making it harder for it to excape the bus.  So the bus has to push harder.

If you create a big tunnel thru the buss and put a wind mill in that you would be able to generate power without using more fuel than the original bus.  But you can't make a tunnel thru the bus without eliminating the motor and passenger area.

If you take a bus and streamline it so that you use less gas than the original bus then you could attach something to generate power from the wind stream and maybe still use less power than the original bus, but you will use more gas in the streamlined bus.

Actually, I'm not sure about that second paragraph. Depends on exactly what that tunnel does to air turbulence.

Or to put the windmill on a stationary object and let nature power it when a wind happens to blow through.

Yep, I agree, there ain't no free lunch.

I had to laugh when the TV news did a story about the "Penta Power" turbine from a backyard inventor who proposed putting it on the roof of a car to generate power while driving. From [url]http://www.pentapowerturbines.com/news.php[/url] "Moore says his "Penta Power" turbine, as he has dubbed it, could have applications in a variety of environments, not the least of which is the automotive world. He sees the Penta Power turbine mounted on an automobile, either under the vehicle, in front under the hood, on top, or by the wheels. As the car moves, the passing air would turn the turbine, and Moore says the electricity could be captured and stored in onboard batteries. "(That power) can be sold back to the grid through future battery depots," Moore says." Is there a term to describe the moment when someone says or does something which completely undermines their credibility?

People keep suggesting these ideas, but the answer is the same. To re-iterate Ork' - the energy comes from the vehicle's engine (which already drives an electrical generator connected to a battery). Fans / mills would increase drag on the vehicle, making it less efficient.
Pushing a turbine through the air (that force you refer to) with a petroleum-driven machine to generate power is much less efficient than taking power from the alternator on the engine.

L

This is the point i want clarified. Now when we take power from the engines alternator we are loading it externally and reduce the effieciency with respect to fuel used and the wheel spinning.
Now what i was saying is assume the wheels friction and the airs friction are the forces that oppose the motion. Now is it possible first to convert part of that air friction.
Please  note that i  DONT mean putting up a windmill on the ROOF of the vehicle , adding another external element. I mean putting it on the face of the vehicle and since trucks/buses are less aerodynamically structured and have a flat face they already have a good amount of surface area hitting the air in front of it. Will placing blades here lead to more friction than a flat surface?

Ofcourse structuring it optimally is another issue but is there some basic flaw in my assumption?

The aerodynamic drag of a stationary vehicle is zero. Drag / friction / force arises by pushing the vehicle through the air with engine-power. If you make the vehicle more aerodynamic it will be more fuel-efficient. You can't improve fuel-efficiency with a circular energy system like this, because all the energy you're thinking of harnessing is coming from the fuel-tank.

L

YES, putting it on the face of the vehicle will further impede airflow.

The basic flaw is the assumption that you can get something for nothing. The universe really doesn't work that way.  The laws of thermodynamics, oversimplified into layman's language, say you can't win, you can't break even, and you can't get out of the game. (A bit more scientifically: You can't create energy, you can't move it without losing some, and a closed system tends to become more disorderly.)

In the very front of the bus is a fair amount. of dead air, you won't be able to extract much from that anyway.

Steve