Hump day Hilarity – China's wind powered car

This hobbyist’s toy is certainly not a realistic solution – as others have pointed out even IF it is generating a positive energy gain it would only be because of the aero inefficiency/drag of the prototype. An equal or greater gain could be accomplished by increasing the aero efficiency/reducing the drag of the vehicle.
That said, as at least one other poster noted, there are situations where the idea could be beneficial. A perfect example would be delivery vehicles – with large “box” form factor. You really cannot streamline a box truck – it is most efficient at its task by being a large square box.
In that case the drag is inherent in the large flat front. You can streamline the nose/cab slightly but its simply rounding the corners on the box – negligible overall gain.
Now take the basic concept of the wind generator and apply to those box trucks. Forward facing fans would not increase the drag – a flat front is a flat front … in fact if properly done adding a ducted fan – with exit path for air – under, over or out the sides – and you’ve reduced the drag coefficient from the stock flat front. Plenty of room in the cab area to duct a fan or fans – you need room for driver is all.
Couple a ram air venturi type duct before the fan that speed air up going to the fan, with proper aero tweeks at duct exits after fan – create low pressure at exits to help scavenge air out of exits. Ducted fans are considerably more efficient than open fans/props.
I can see at least in theory a positive gain.
Now add consider adding solar panels to roof, regenerative braking, and perhaps a KERS system (which stores braking energy in a rotating high speed flywheel) and you could see a small but real net energy gain.
This does not speak to financial feasibility only to energy. If it was cost effective we’d see it in operation as these aren’t cutting edge ideas. But “cost effective” parameters often change rapidly.
People need to come up with hair brained ideas for there to be meaningful real progress.
For example years back who’da thought having a dead cylinder in an engine would be a good thing? Yet today engine management systems routinely kill a good share of the cylinders in an engine to achieve increased fuel economy.
I don’t know if this ultimately would make sense – but I can certainly see applications where it MIGHT be feasible.
http://en.wikipedia.org/wiki/Kinetic_energy_recovery_system
http://en.wikipedia.org/wiki/Regenerative_brake
Ducted wind turbine idea:
http://www.technologyreview.com/energy/21737/?mod=related
F1 and Indy car racing – and aviation – engineers have become expert at aero – decreasing drag, increasing efficiency – but also making air flow do what they want … a good example is using exhaust gases to create low pressure areas to help air flow by creating low pressure areas …the Lockheed L1011 if I recall, while it has a 3rd engine in the rear – has it actually in tail of fuselage, not mounted in the vertical tail as with DC 10 – and fed by an “S” duct – in doing so they reduce drag and increase efficiency of vertical tail so it can be smaller (and fit in smaller hangars).

I am appalled by the lack of foresight by the naysayers. I suspect that I have at least as much knowledge and experience with the laws of thermodynamics as the majority of the commentators. I see this as one of the financial opportunities of a lifetime. All I need is some deep pocket investors to finance jumping through all of the hoops to bring it to fruition as an IPO as well as subsidize all of the legal hoops so that I can be properly licensed to handle the IPO. It appears reasonable to me that we already have a huge potential market starting off with Mr. Gore, Mr. Hansen, Mr. Jones and Mr. Mann et all. The prospect list would include everyone at the IPCC as well as reputable scientists at universities and government funded climate research around the world.
I am sure that I my conscience would be able to rationalize any obscene financial rewards that I might receive as compensation for my contribution to the green revolution.

It might even reduce drag in some circumstances. Depends on what it’s being compared to.
Consider an air particle hitting the blade and pushing it laterally due to the angular incidence. The lateral force does not impede the vehicle’s forwards movement. A force that might have otherwise impeded the vehicle’s forward movement is used in an energy conversion towards the enclosed car-turbine system.

John T says:
May 16, 2012 at 11:10 am
“The problem of energy loss was solved long ago with regenerative braking, stand on most modern electric vehicles – Anthony”
And if you don’t have modern electric vehicles? And how many modern electric vehicles can be built for £1,000?
…
I agree this isn’t going to do much of anything to cut smog (the article was over the top). It wouldn’t win any design awards in this country. And I don’t see this design going into large-scale production. But I admire his spirit. We have modern electric vehicles (and a whole lot of other things) because of people like him. And its someone like him who knows we still haven’t solved the problem of energy loss, just reduced it some.
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To begin with he hasn’t created an electric vehicle that could be sold and driven on the roads legally in the West. I suspect if I wanted to make a homemade golf cart that didn’t meet safety standards I could do it for under $1500.
Second, he hasn’t reduced energy loss at all. As others have pointed out any energy he extracts from the relative wind comes out directly as additional drag losses and given the less than perfect conversion of wind power to electricity and finally to mechanical work there must be a net loss in energy. Work (Energy) is Force x Distance. The fan experiences a force due to the relative motion of the air flow which does work on it creating electricity. Unfortunately, the car experiences at least the same force (maybe more if the fan housing further increases drag) and moves the same distance losing the same amount of energy. It is absolutely identical to using a battery to drive an electric motor connected to a generator used to charge the battery.
Fred Berple pointed out that if there is additional wind relative to the ground then there is a source of energy that could be extracted. That’s true, but it’s really no different than putting a sail on the car and clearly not what the so called inventor is claiming.
Others have suggested that he’s harvesting energy lost to turbulence around the vehicle. Let’s put aside the fact that his fan placement and configuration clearly do no such thing and assume he did configure them properly, say normal to the plane of the ground. OK, now he’s extracting energy from the turbulent layers around the vehicle and making the car more efficient. There’s only one problem. He can only extract a fraction of the energy going into the turbulence and turn it back into useful work. As a result he would have been better off designing a more aerodynamic shell resulting in lower drag and turbulence losses to begin with.

DavidA says:
May 16, 2012 at 7:26 pm
It might even reduce drag in some circumstances. Depends on what it’s being compared to.
Consider an air particle hitting the blade and pushing it laterally due to the angular incidence. The lateral force does not impede the vehicle’s forwards movement. A force that might have otherwise impeded the vehicle’s forward movement is used in an energy conversion towards the enclosed car-turbine system.
—————————————–
Draw the vectors and the free body diagram of the flow and the fan blades. You’ll find that the drag force and the force acting on the fan blades is the same regardless of the angle of attack. Any energy you extract due to lift on the blades will show up as lost energy due to lift induced drag times the velocity of the air. If that weren’t the case then all aircraft would be perpetual motion machines once they got into the air. It takes energy to sustain flight.

Crono141,
Sorry but HOH generators are a load of crap. The 2nd law of thermodynamics guarantees you’ll get less energy from burning the HOH than you used to make it.
Consider the fact that automakers invest billions of dollars in research to get modest improvements in fuel economy. If it were that easy to improve fuel efficiency, don’t you think these devices would be standard on every car?

You can get an electrically powered paraglider 🙂 Better than a flying car, too 🙂

Actually, all he really needs is a couple of Senators instead of the reporter and he would be in business.

Tsk Tsk says:
May 16, 2012 at 8:40 pm
You started out mostly right except that he simply cannot be producing more energy than he’s using excepting berple’s ambient wind.
The modifications you propose to the trucks would further increase drag as the airflow now has to do work against the fan itself and not just get out of the way, so to speak. Any improvement you would get out of such a system would be due to a net reduction in drag due to your ducting. I don’t need a fan to accomplish that. Basically, you’re violating the constraint that you can’t improve the aerodynamics of the trucks that you stated at the beginning.

A box delivery truck already has a finite fixed frontal area due to the “box” on the back. It is 96 – 102″ wide by appx 6′-14′ tall. Because they are dragging that box – that large flat frontal area – around behind them any aero improvements in the cab area have nominal effect. Therefore drag is largely a fixed number. You can not make it significantly more energy efficient.
Thus a fan is no more impeding to airflow than the existing front of the truck. You can plaster fans all over the flat front and the truck would be for all practical purposes be little changed than the flat front without fans.
To be efficient though a fan needs an exit for airflow. You could simply exhaust them into the engine bay and allow to make its way out the bottom. However it is better to put the air to work – make it go where you want it, and in some case perform a useful purpose at the same time.
As I noted – modern race cars – Formula ` and IndyCar – are masters at that. using aero to “shape” air in many different ways – to direct air to or away from wings to increase or decrease their efficiency (some times you went less downforce in order to decrease drag, other times you need more).
A good example are what are sometimes referred to as “wheel flips” – small bodywork in front of rear wheels. The rear wheels are exposed to the airflow – so have a large frontal area – AND create their own turbulence by their rotation. Wheel flips re-direct the air to assist in smoothing the turbulence around the wheels. Although they have a drag penalty by placing them in the airstream it is smaller than the drag saved by creating what you could visualize as an “air fairing” around the wheel.
Fans can be and have been used in racing to enhance – greatly – the aerodynamics of the cars. In 1978 the Brabham BT46 “fan” car lasted exactly one race before being banned. IT used fans to help exhaust air from under the car making it highly more efficient. It was banned after a single race. The car had aero effects already – the use of the fan greatly enhanced their efficiency – which pokes a gaping hole in your comment that you could simply cut the holes/ducts for the fans in the current example and achieve the same gains with the fan drag.
Prior to that – in 1970 Chaparral 2J CanAm car also employed fans to create increased aero efficiency. It was soon banned as well – with McClaren complained if it were not the CanAm series could be destroyed.
These are not perfect examples but they do show the potential.
A more real world example might be another racing aero “trick” …race cars have employed “ground effect’s” since the 70’s – where the underside of the car is shaped like an upside down wing – to both enhance and smooth airflow under the car, and to cause air to speed up – which causes low pressure area under the car – holding it to the track.
Aside from the profile – the underbody wing shape – there are a couple restrictive issues. One, the air must be kept under the car and moving fast from front to rear – not allowed to leak out the sides. The other is to speed up the air you need an airfoil – a surface that is longer than the physical length – so the air can be sped up.
Early designs had movable flexible “skirts” attached to the car that slid on the track effectively sealing the sides so air must stay under the car. These had many problems – drag, wear, catching on track imperfections and ripping side of car off etc. The car must have suspension travel to function so these could not be fixed height. They were deemed “moveable” aero devices as well, which had been banned for many years (ie: wings you could set flat on high speed sections to reduce drag – but would pop up on slow speed areas where the car needed the extra downforce.)
When the “physical” skirts were outlawed the propeller heads and rocket scientists simply came up with a different way. They use fixed aero devices that directed airflow at the front edge of the bottom of each side of the car to create a “vortex” – a small rotating air mass. Those vortices created an air seal as they traveled along the bottom of the outside edge of the car between the road the bottom of the side of the car. Same basic effect as physical skirts without anything to break off.
You have experienced a similar effect if you’ve walked thru a doorway and felt a blast of air – an “air curtain” – which uses high pressure air to create a barrier to keep inside air in and outside air out.
Now the other issue – the underside “wing.” To create a “wing” shape under the car means the bottom is higher from track at front, then gets closer to track partway back and the gets further from track – like this:
http://www.ddavid.com/formula1/images/lotus79b.jpg
In doing so the air is restricted at the narrowest point – where bottom is closest to ground – if this air does not keep moving – and faster than the actual vehicle speed – the underbody does not work. One way racing engineers dealt with it is the wider “exits at rear of tunnels – creates lower pressure which tries to pull air toward rear. To improve that even more some teams exited their exhausts into these rear diffuser areas – this air was traveling fast and directed rearward and acted as “suction” helping keep air from packing up under car.
Many of these technologies are making their way to commercial over the road trucks – which are horrible for aero efficiency.
Examples here:
http://www.solusinc.com/splitskirt.html
Last I would point out that ducted fans have a high degree of efficiency – they also produce a high speed higher pressure “exit” airflow.
Thinking outside the box – theoretically – it seems ducted fans could be used on commercial transport trucks in many ways. They spend most of their life running 60+mph. They are also extremely aero inefficient. It is very hard to icnrease drag. There are more and more methods to decrease drag by nominal amounts though
I can – again at least in theory – see ducted fans on these vehicles that use the constant airflow for energy generation and then the exit air being used to cleanup airflows increasing aero efficiency and fuel mileage. For example feed high velocity ducted exit air under the trailer to clean up turbulent airflow. Or use that same exit air run past a vortex generator created an “air curtain vortex along the bottom sides of outer edge of trailer – an air version of the “skirts” shown above – air skirts would have 100% ground clearance while at same time helping keep air out from under trailer.
I can easily see ducted fans providing enough power that alternators could be disengaged – saving fuel and increasing engine efficiency as well.
Again – it may not be economically feasible but I think it is technically possible. I don’t think “goes 3 times farther” is anything but silly blather – but neither is the idea completely far fetched.
Again – who woulda thought killing a number cylinders in your engine being a good thing.
And how do you think that first guy, sitting around drinking beer with his buddy’s, who said “hey guys I gotta great idea – I’m going to build an invention that creates POWER when you put on yer brakes” got treated.
I image he heard some of the same responses as we see in this thread 😉
In a little over 100 years we have gone front first aircraft flight to putting a man on the moon and much more.
Where would we be if all the great (and often way out there) people who have dreamed all the new things we’ve seen in our short lifetimes had that same “why?” mentality. Instead of ‘why bother it’ll never work’ – they said ‘why the heck not – lets find a way to MAKE it work’ … seems we need more of the “why the heck not” folks these days.

Box truck in wind tunnel 😉
http://wwwm.coventry.ac.uk/SiteCollectionImages/engineering%20and%20computing/Facilities/Wind-Tunnel.jpg
I’ll note that I am not advocating any of this necessarily works, makes sense, or should be done … simply that people need to look for possibilities. Even hare-brained schemes and outright silliness can contain a kernel of usefulness.
Tiny improvements in fuel economy in over the road transports can add up to large fuel savings.
Using this “toy” as a catalyst – silly as it is … forget using it to power the vehicle … why couldn’t we look at using ram air systems to take over at speed for alternators, generators, hydraulics and the like? Seems at least conceivable that a direct drive fan or RAT style wind generator like aircraft use might be more efficient than a massive belt driven alternator powered off the engine? Is the drag from the prop against the efficiency of direct drive and the electronics, better than the very “lossy” and inefficient big ol’ v belt run off a $4.80 a gallon diesel motor also trying to haul 80,000 lbs down the road at 60mph?
I don’t know – but would be pretty simple to find out 😉

DickF says:
May 16, 2012 at 8:39 am
“Dave, it’s been done. Many modern aircraft are equipped with a Ram Air Turbine (“RAT”). The RAT is normally retracted in flight, but can be extended to produce emergency electrical power in the event of multiple generator or engine failures.”
Sorry Dick, I should have used the sarc/ tag. I’m fully aware of RAT’s, but their use is only for emergencies, and the additional drag is probably the least of the worries a crew with a crippled plane will have.