My daughter had an idea... Would it work? Air scoops on cars to create power.

[Bonobo]

while you drive...

Could you use the power of wind resistance to create power? How much would it be? Is it feasible?

Thanks to anyone for their 2 cents.

[TexasProgresive]

1. There is no free lunch.

Any power made would increase drag that would use greater energy. That is unless you were sitting still in a wind storm.

[Harper_is_Bush]

2. It's not without merit. What about when you're coasting?

It's similar to the concept of kinetic energy garnered from brakes on some hybrid models.

Of course, when accelerating the acceleration needs to compensate for the energy absorbed by the wind cups, but at all other times it would be a "free lunch".

[TechBear_Seattle]

4. When you coast in a normal car, why do you stop?

Because of the friction of the road against the tires. Add in the friction of air against the wind cups, and you will stop that much sooner.

Again, TANSTAAFL.

[Harper_is_Bush]

10. Yes, but the windcups would also be part of the reason you'd stop, no?

Take his daughters idea a little further.

Picture a car with a raisable (raiseable?) wind-cup generation device. Similar to the kinetic braking power generation employed in some cars today, it would only come into play when you're not gassing the vehicle.

It's a brialliant idea.

[tanstaafl]

23. When you coast in a normal car, why do you stop

Because of the friction of the road against the tires. Add in the friction of air against the wind cups, and you will stop that much sooner.

Again, TechBear_Seattle.

[TomInTib]

3. Look at it another way.

Scoops cannot create power (unless it on 60s-era ram-air), but they can enhance ground-effects and streamline efficiency.

But most gains are self-cancelling except at really high speeds or rate of acceleration.

[Strelnikov_]

5. No

Energy is being used to propel the vehicle, creating the velocity differential between air and the mass. Additional energy would be required to compensate for the increased drag of the capture device. With said device being inefficient in recapturing the energy expended, it would be a big energy loser.

One could have a wind capture device in a louvered enclosure, only capturing airflow during deceleration or on hills. Thing is, a much better way to recapture kinetic energy and static potential (hills) is through regenerative braking in an EV.

EV. It's ready. We just need to do it.

[Harper_is_Bush]

11. what if the "capture device" was only employed at times of non-acceleration? n/t

[Strelnikov_]

15. That would recapture energy

That is why I noted a 'louvered enclosure', sort of like the torpedo doors on a sub, open to capture, close to minimize drag.

Problem is, the capture efficiency of wind power devices is so low, and the complexity of a system like this so high, I really don't think it would be practical considering regenerative braking is proven and available.

[dweller]

6. indirectly

air scoops on air cooled vws kept the engine temps and oil cooled for optimum operating conditions.
The main cooling fan captured and distributed the air over the main engine parts. Without the air, or the fan blowing, it was a short time before the engine's power and performance suffered and the engine would overcook, and quit.


dp

[liberal N proud]

7. Sail boats use the wind

But the efficiency and dependability would be only one issue.

[madokie]

8. that would be a form of pertetual motion and the answer is no

due to the fact nothing is 100% efficient the end result would be a net loss of energy, most times the wasted energy would only be turned into heat

[Harper_is_Bush]

12. The OP wasn't claiming the system would propel the car, or create energy out of nothing

as in "pertetual" motion. :)

A point I've made elsewhere, at times of non-acceleration, such a device would be a benifit. It would be "free" energy.

[skids]

18. Only on cars without regenerative braking n/t

[madokie]

19. the net gain would still be less than zero

maybe in a situation where you are going down hill all the time could maybe something like this happen. consider the fact that the engine would have to run further into the stop, ie using more energy, in order to make it to the place you want to stop if you put more resistance to its forward motion as is being proposed. as I said it won't work.

it would be nice if it would ;-)

[EvilAL]

9. hmmm

If you don't make "cups" or whatever, just find a way to grab the air coming into the front of the car and send it through fans to generate power it would depend on how much extra drag the fans create. You'd lose battery life. The drag that would have been produced by the car itself wouldn't be added to that, it would have been there anyway.
If you can have 2 sets of batteries for instance, 3 hours each, and be able to recharge each set within 3 hours while driving. Once one set gets low, switch to the charged ones and begin charging the dead ones. I don't know how much energy a battery powered car uses and how long it takes to charge them though. So it might not work at all.

[skids]

17. I'm not sure what advanced theory says about it...

By rough theory it might be possible to use a capture system
to improve aerodynamics and reduce drag. However, it's also
likely that the expense would not be justified since there are
many clever tricks that have only begun to be explored just
playing with the shape of the hard shell, e.g.

http://www.airtab.com/

However anything that isn't an aerodynamic shape on the
front of the car is going to add to the overall drag and
it would have to be a pretty ingenious system to overcome
the efficiency losses of energy conversion in a way that
ended up with a net gain.

[Harper_is_Bush]

13. How old is your daughter? She's a smart cookie.

I could envision a system that was exposed only during periods of non-acceleration.

Maybe flaps that opened on the front of the car to expose the wind-cups, and quickly closed upon acelleration.
Or the driver could control the opening of the flaps....since the driver would know if the non-acceleration includes the desire to slow down.


Such a system included with a hybrid car could charge the hybrid battery.

[Bonobo]

14. She's about to turn 13.

She speaks and reads Japanese and English fluently and has been playing violin for over 7 years. She is a smart cookie indeed.

Thanks for the information. She will be so happy to hear the compliments!

[OKIsItJustMe]

16. By all means, encourage creative thinking

However, TANSTAAFL rules here. If you're putting energy into accelerating the car, or even keeping it going, this system would only make things less efficient.


If the system is used to help slow the car, then (in theory) you would have a form of regenerative braking. However, there are much better ways to recover this energy.

Now, here's an idea... recover energy from the flexing of the suspension. ;-)

[Turbineguy]

20. When I was driving the freeways of Los Angeles

(nearly a half century ago now) I had an idea for a car powered from the noise of the other traffic.

[jimlup]

21. violates simple physics

Doesn't work. You don't even need the first law of thermodynamics to show it won't work. Simple mechanics and energy conversion shows that the net energy gain is zero or less, regardless of crusing or accelerating.

[Harper_is_Bush]

22. Why wouldn't it work?

It would generate electricity, correct?

Therefore, if it's used ONLY when deceleration is the drivers intent, it quite obviously results in a net gain.

Sort of like generating power from the braking system.

[lumberjack_jeff]

24. It's exactly like generating power from the braking system

The wind scoops are rudimentary air brakes that, unless they retract every time the operator depresses the accelerator pedal, are on all the time.

Better to make a light aerodynamic car with regenerative braking and PV cells in the roof.

[Harper_is_Bush]

25. Yes. And if the wind scoops were behind a retractable shield

that the driver could open when deceleration (rather than just cruising) was intended, then it would work perfectly.

[jimlup]

26. flywheel

There is a much easier and more efficient way to recover energy from braking. It is called a flywheel. Hybrid's use this method. Aerobraking would be subject to inconsistencies, buffeting and wind. I'm not going to bUy an energy recover areobraked mobile!

[NNadir]

27. If your daughter is in high school, it's time to think about learning the first law of

thermodynamics.

[Bread and Circus]

28. It wouldn't "create" power but it could reclaim energy. however, the issue

is that any device that reclaimed energy would increase drag. I'd leave it up to an engineer how that might work out if you replaced some part of a car that would normally experience wind drag and replaced it with some form of recuperative device. Instincts tell me you would always face a net energy loss, better just to make it as aerodynamic as possible in the first place and boost fule mileage with diesel engine/electric hybrids or go electric plugin powered by a variety of non fossil fuel electricity sources (nuclear, wind, solar, hydro, etc.)