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Wind Wheel Under Grille - Extended Range Innovation -

So I was looking online at electric cars and their range and then I started to think about the wind resistance cars get on the road and how that could translate to creating electricity. I got to thinking on the model S they could place a long narrow water wheel shaped wind turbine across the bottom front end bumper so that as air passes through from wind resistance it charges the battery as it moves along to create a self sustaining system by adding to the current range of the car. The Germans have started testing using wind charging as a stop and go technique in Australia but I got to thinking that it would make more sense if Tesla made an aerodynamic wind wheel located under the front grille. There are light weight materials you could make it out of so it would not slow the car and cause drag such as carbon fiber or aluminium e.c.t.

Just thought I would provide this idea to Tesla I am in college now and am getting to be a bit creative when looking at ways to improve things. Hope someone has a look at this idea and feel free to ask any questions !

The slowing and dragging has little to do with the weight of the materials. Friction and thermodynamic inefficiencies and conversion losses mean you never recover the energy put into "pushing" the fan ("wind wheel") through the air. And all that energy came from the very same battery you're trying to fill.

I have a deal for you! A crisp new $100 bill for only 6 old wrinkled $20s. I can supply as many as you want.

Nice thought experiment for any college attendant:

A volume of air sits still. Kinetic energy is zero.
A car passes though that volume, making air swirl. Kinetic energy is transferred from the car to the air.

There is no way to gain back more energy from the air than used to move the car, since the energy content is zero at the start.

Enter Model S version 6.0 with a sub-zero Cd (just a few years from now...), passing through the same volume of air. Now you have a thought experiment! :-)

This is another example of how the Model S would get better range in stop and go traffic than on the highway. On windy days, when stopped, you extend a wind/electric generator. Before you go, retract it. What could be more fun!

Innovator93, when you get to your Physics classes you'll note devices of this type violate the first and/or second laws of thermodynamics.

Simply, you expend energy to drive the car forward to generate the "wind". You collect the wind energy imperfectly since your fan and generator suffer from friction and losses in the generator. You then put this back into the battery suffering losses in the charging process. You take energy out of the battery to drive the car forwarward with the motor suffering friction losses, inefficiencies in the motor, etc... This generates less wind, etc, etc... Keep repeating the cycle. Energy leakes away to heat with every iteration. Entropy must be maximized.

Just one cycle probably has a total efficience of less that 40%

Kind of sad, but not only can't you generate power, you can't even break even. Entropy must be maximized.

Stationary wind generation does not violate thermodynamics because the energy comes from the environment. Even that is subject to thermodynamics. Ultimatly the entire process is driven by nuclear processes and friction from gravitational attracction but that's still maximizing entropy.

Do you want to change "Entropy must be maximized" to "Entropy must increase"?

Hopefully we, as life itself does, can find ways in which entropy is increased minimally.

I believe that airplanes are equipped with wind turbines. In the event of a catastrophic failure, the wind turbine is deployed beneath the fuselage. The turbine then generates electricity to run the essentials of the airplane.

Yeah, if they were smart, they would deploy wind generators on jets. Since the jets are flying so much faster, just imagine how much electricity they could generate!

EdG. I could go with Entropy must increace.

Stephen, if so, any power gained is offset by a larger net loss of kinetic and potential energy. Drag from the turbine would slow the airplane (kinetic), resulting in an eventual decreace in altitude (potential) I say this only to help our young student not get his hopes up.

I believe commercial aircraft have APU's (Aux power units) that are turbine driven generators running off aviation fuel from the aircraft main tanks.

Mycroft,

Electrical energy generation on aircraft from turbines would be enough to supply major power to the grid, but is offset by the aerodynamic drag of the tied together extension cords hanging off the tail of the plane.

But I think I just figured out why the turbine wheels give the car extra range.

Even if we could break the thermodynamics laws, no fan is going to provide the 0.3 kWh/mile required to keep the the batteries topped up. Do the math.

Inovator93 keep that idea on mind. You can't achieve a perpetual motion machine(laws of thermo and all those things), but I imagine you have a point if you see the idea with the same concept as the regenerative brakes. (A way to recharge partially the batteries)

The fan could generate a current, and they'll have to study if it's efficient or not. Maybe the weight of the fan could increase the consumption of power more than the fan can generate, or maybe not in which case will be a good innovation.

Weight is irrelevant. If the fan is attached to the car, the push of the wind is also a push on the car. Then you start wasting energy getting the spin-generated % of that push into the battery.

Guaranteed loser.

Innovator93,

The energy density of wind is rather low. If you really want to get usefull power, you get it from the drive train. A luxury sedan at speed has a lot of kinetic energy you can recover when you decelerate.

Tesla deliberatly chose not to use hub motors for a couple reasons. Total weight particularly unsprung weight, difficulty with making hub motors for alternating current, cost of having 4 motors, etc. It would have given all wheel drive, and all 4 wheels would regen.

In the Tesla, only the back wheels can regen. Braking on the front is friction only. I'm guessing the Tesla will attempt to regen on light braking, but eventualy the front calipers come into play then it's lost to heat.

Driving in reverse however.... Now that will charge the car. (kidding)

Time to stop this nonsense of a wind turbine refilling he battery. The arrangement is another example of an impossible perpetual motion machine of the simplest kind and will not provide more energy to the battery than is extracted from the battery to accommodate the additional load of the turbine. For every Watt generated by the wind turbine the motor has to put out more than that Watt to move the arrangement through the "wind". Further, even more power than that has to come out of the battery to drive the motor.

If you still believe in the possibility of this wind turbine arrangement working, then you would be much better off, and not require any additional equipment, by simple stepping on the brakes while driving with your foot on the pedal and using the regenerative braking to supply the battery. This, of course, is ridiculous, but not more so than the perpetual motion machine arrangement. Time to learn some basic physics.

I believe Tesla has decided, for simplicity of design and, therefore, reliability, to do regen only when removing your foot from the accelerator. Braking is simple braking.

The level of regen you get when lifting your foot may be programmable.

Zelaza, back off and bug off. For the umpteenth time, Innovator brought up a perpetual motion/free energy scheme. They've all instantly been shot down. This thread is actually a rehash of many others.

Your self-importance is seriously undeserved.

EdG;
There's an xkcd for every situation. I think a year or two ago I started at the beginning and read them all. My fave may be the one with our hero facing a dude standing in mid-air, who says, "The universe does NOT work the way you think it does." Or WTTE.

;P

Just read over this and confused. Who cares if the wind turbine wouldn't charge the car back to full battery? If you were able to install a light wind turbine into the grill of a car, or spirals along the side inside of vents, wouldn't it be able to partially re charge the battery and extend the number of miles that you can drive on a single charge?

@hey: Yes and No.

Yes: If the car is parked on a hill facing into the wind, the wind could recharge the battery, just like any other windmill.

No: If the car is moving and there is no wind, then the turbine adds drag and the amount of energy generated would be less than the energy used by the car to create the relative wind due to the extra drag. Net loss of range.

Theoretically, a windmill that was oriented perpendicular to the direction of travel and was enclosed in a fairing that minimized forward drag could generate some energy from winds that crossed the path of travel. This would be what I call the sailboat effect. I doubt it would produce enough energy to make it worth doing, however. Think about only running the car using the prevailing winds, like a sailboat, and how much "sail" you would need to make it useful. :-)

It is NOT against the rules of physics to suggest a wind turbine could be used to increase the range of an electric vehicle by providing some regenerative effect to the batteries. Why? Because the car is MOVING ANYWAY. If someone were to argue they were going to build a propelled vehicle to push a wind turbine down the road to generate a wind field which would then be used to turn a turbine to create electricity, of course they would never get more energy out than they put in. But, a car, by necessity, has to move anyway and the wind field is a by-product of that movement. It is about re-capture.
The principle is the same as capturing the energy from an exhaust gas stream in an internal combustion engine (i.e., a turbocharger). Do turbochargers require more energy than they (help) create? Absolutely not. All else being equal, a turbocharged engine is more efficient than a non-turbocharged engine.
Suppose a couple of canned type wind turbines were strategically placed to minimize drag, maybe where air flowed anyway - like in a brake cooling duct, the issue is not about perpetual motion. the real question is could the necessary components be made light enough to warrant the extra regeneration they provided? I think if the car were constantly moving, the answer is absolutely yes (we are talking about extending range, not running perpetually). The problem is the extra weight may not be worth it considering stop and go type driving.

So.. If we take a funnel and connect it to the hose of a dyson vacuum cleaner....

It takes energy to produce energy. A wind turbine on a car may produce electricity but it will always consume more in terms of drag resistance than it can generate.

@Tim.Enfinger
nope.

The windmill on the car can only produce energy that it gets from the car pushing it through the air. This requires the car to use more energy to push the windmill than it it were not there. The energy that the windmill can capture and return to the battery will be less than the amount the car had to use to push it.
The only way the windmill idea would actually result in a net energy gain is if the car is parked in a windy area allowing some small amount of recharging to occur from the wind's power, or while traveling downhill. In the first case, the weather is supplying the energy to spin the windmill. In the second case, gravity is. When you are driving on flat terrain, or uphill, the Tesla battery is supplying that energy.

The Turbocharger uses energy that is created by the ICE but is normally wasted. The pressure of the exhaust gets captured and is used to force more air into the combustion chamber. This is a completely different situation.
You reference perpetual motion a few times so I assume you have been told that a perpetual motion machine is impossible already.
For people that don't have a great understanding of physics, it is often helpful to take thought experiments like this to the extremes to get an idea of why they don't work.

Consider this. If your idea was capable of supplying some free energy with 2 small ducted fans, than why wouldn't 2 more provide a little more energy? Take that to the extreme and you will see that for every fan added (according to your argument) you will get some additional return of energy. If you keep adding ducted fans at some point the amount of energy created would exceed the amount required by the car to move forward through the wind. At that point, you could disconnect and drop the battery since the little windmills are supplying more power than it needs to keep moving. This would reduce weight and the car would really take off! Then you would have a car that runs by itself, with no internal source of power, right?

Suppose a couple of canned type wind turbines were strategically placed to minimize drag
Take this to the extreme. A windmill requires drag - that is what makes it turn. If you minimize drag to the extreme, the windmill will not turn at all!

Ok. I am struggling with this. If we connect a funnel to a Dyson, that Dyson had a turbine-generator, and that turbine generator were connected to a battery, then the Dyson could be made more efficient (nowhere near self-sustaining), right? It would certainly be more complicated and more expensive.

Why doesn't a turbocharger create more back-pressure and thereby consume more energy than it produces? Drag applies to a turbocharger, correct? My reasoning is because the exhaust stream exists anyway, then a turbocharger captures energy that would just otherwise be lost. Another way of looking at this is if a group of tiny, short-lived, but incredibly productive creatures lived on the roof of a Tesla, and decided to build a wind turbine to generate electricity from the wind they noticed was passing by, the electricity they produced would be net positive to them. Their wind turbine on the roof would be equivalent to them to our wind mills on earth - just capturing energy that happens to be there anyway. In theory, they could supply said electricity to the battery, thereby increasing the car's range. Thanks for the fun thought experiments, and patience.
I think I may be wrong, but it is still fun to think about.

Thanks PBEndo. I posted before I saw your reply. This was fun. Thanks for humoring me.

Yep, I admit I am wrong. BUT, if we put an ICE in the Tesla and then captured its exhaust to turn a turbine to make electricity... Just Kidding! Thanks again. I'm outta here...


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