if we’re trying to extract energy from the exhaust, we’re far better served with turbochargers and turbo-compounding.
Somehow it’s difficult for some people to understand the laws of thermodynamics. Sure, if you can recover what’s otherwise lost, that’s a good thing. But if you need to add more energy to get back some, it isn’t practical. And adding a lot of weight and complexity to get a marginal improvement isn’t going to excite many engineers.
But don’t let me stop you. Go to work in your garage and let’s see what you can do!
for a car, the engine’s coolant is just about the normal boiling point of water at STP. It’s not nearly hot enough to be an effective heat source for a steam engine.
for stationary engines, we do see that in combined-cycle power plants, where the exhaust of gas turbines is used as the heat source for steam turbines.
Yeah, but you’ll never get that through the McDonald’s drive-thru.
Why would adding weight to a stationary engine require more energy input if the exhaust was simply used to preheat water for a steam turbine? I am in full agreement that adding contraptions to a moving vehicle would arrive at a net loss of power.
Well, then, we are in agreement, aren’t we? What good would a net loss of power be?
I can see it now, the ads…“Be the first in your neighborhood to buy our Super Turbo Quantum Energy Recovery Box! Only 30% net loss!”
I, for one, would love to hear what the OP’s insights are on the old airplane on a treadmillissue. We might just get this solved once and for all! 
Yes, but you can go directly upwind faster than the wind too. In both cases you need wind relative to the ground, as an energy source.
The thing that trips a lot of people up with DDFTTW vehicle (and others like it) is that conservation of energy doesn’t mean conservation of velocity.
Ohh no you didn’t :smack::smack:
WTF? I can’t believe you went to all that trouble to (apparently) ignore the fact that (assuming there’s no cross/head/tailwind) any work you can harvest from a car-mounted wind turbine is being done by the car.
Windmills on an airplane on a treadmill. (once, in Rio for twenty minutes a 50’s style goat wasn’t in a wheelchair)
That’s a perfectly reasonable suggestion, from an energy point of view. Heat is often recovered from stationary engines (from the cooling water, the oil and the exhaust) and used for various purposes. If there happened to be a steam turbine conveniently nearby, you could certainly dump the heat from the engine into the bottom of the steam cycle.
From an economic point of view, it could well be worthwhile. I am familiar with a power station that consists of 2 x 40 MW diesel engines, run in simple cycle. That’s dumping over 80 MW of heat to atmosphere, which would displace a hell of a lot of fuel in a steam cycle.
I can’t believe he failed to cite prior art:
http://www.memecenter.com/fun/241597/troll-physics
Indeed - the notion that you can’t get more out of a system than we currently do is a sloppy assumption - and not equivalent with the fact that you can’t get out more than you put in.
On the hopeful assumption that the OP is in some way serious, but just struggling with the math…
Forget the wind turbine for a moment. Install a fifth road wheel, trailing behind the car, and have this fifth wheel drive a generator. Is there any way that generator can produce enough power to run the vehicle sustainably? Obviously not.
And the wind turbine idea is the same, with the exception that there are greater losses involved in extracting energy from moving air than there are with a mechanical coupling such as the above-mentioned fifth roadwheel.
Obviously not… unless the generator wheel runs on a different surface than the engine wheels, and there is a velocity difference between the two surfaces:
And bumblebees can’t fly.
Regarding Blackbird, the wind powered car that runs directly downwind faster than the wind that is powering it:
The prop is “sailing” along a downwind beat. Just that is not constrained to a water surface, so it is moving in a continuous helix, rather than doing a series of jibes to zig-zag.
The usual objection is that the car is outrunning it’s power source. It is in fact continuously catching up to it’s power source. It grabs the moving air from in front of the prop, and slows it down (relative to the ground) extracting kinetic energy from that air in the process.
Quite - and that’s a good demonstration of the basic principle behind the Blackbird DDFTTW machine, however, it’s my impression that the OP is talking about a car driving in a wind-less environment, and somehow extracting useful work from its own forward motion through the air.