Ok, I've heard some pretty far fetched ideas on Discovery's tech specials, but this one takes the cake. On FutureCars - the Fuel, the narrator boldly states that a generator run on compressed air can compress air and run a car - a perpetual motion machine. He doesn't state this tongue in cheek, but boldly as a real possibility.
Any teenager who's gone further than General Science in High School can tell you THIS IS NOT POSSIBLE! And you have the audacity to imply that it takes little to no energy to compress air, when any engineer can tell you a piston compressor is one of the least efficient machines on our planet.
Discovery is more than a media outlet. It fuels young imaginations and incites them to become scientists and engineers. That is, unless the information is tainted with fatastic drivel like a possible perpetual motion car!
Please be a little more socially responsible in your programming!!!
HOLY COW! If anyone knows how to forward this to the right people, please do.
ATTN: Discovery Channel Execs
I watched "Future Cars" this morning and was actually very offended. Yes, offended. As an engineer/science enthusiast/education advocate I find it wrong to suggest scientific authenticity in the idea that a car could run on perpetual motion. That episode left my jaw on the floor.
Not to blow my own horn, but to lend credibility to my furor, I will describe my background. I studied mechanical engineering, focusing on thermodynamics, energy conversion, and engines. I have worked on both the fueling side and the vehicle side for CNG, LNG, H2, and hybrid electric vehicles for the last 7 years. I've constructed and driven H2 fuel cell-powered machines. I've (professionally) examined compressed air engine technology.
If I had to guess at the three most important questions for any engineer to ask about any technology, it would go like this: 1. Is there any obvious reason that this is not possible? 2. Is there any chance that this could be efficient/practical/economical enough to be of use? 3. Is this better than other ways to do the same work?
Let's see how your FutureCar episode stacks up here: 1. Perpetual motion is impossible. Period. 2. Nearly any time energy is converted from storage to work, there is a significant inefficiency. In the case of compressed air, it is a huge inefficiency. 3. No. Internal combustion engines are surprisingly cheap and efficient, especially when coupled with hybrid technology. Hydrogen fuel cells are even more efficient (acknowledging the challenges with H2 production and storage). Battery-electric vehicles have the potential to be even more efficient.
I started to get leery when the French "inventors" (they did not actually invent air engine technology - that has been around forever) failed to acknowledge the challenge of filling the vehicle with compressed air. To fill that car with enough compressed air for 200 miles of driving reqires LOTS of energy from compressors that are no doubt inefficient (a typical electric-powered compressor turns 80-90% of the electricity into heat). These would also be expensive filling facilities with high maintenance costs. The electricity comes from power companies that might be burning fossil fuels such as coal. As the French inventor sniffs the air to indicate how clean his car is, he would be inhaling carbon dioxide, sulphur dioxide, and mercury from the power plant the fueled his "clean" car. (Of course the political climate in France allows for widespread use of clean nuclear power, but that's another story.)
Yes, that was the sort of truth-bending that we usually get from the news media. It insults the intelligence of your viewers. But wait! It gets worse! Since the air exhausted by the motor is cold, the narrator suggests that use of the car would actually cool the climate in "thermally-challenged cities such as L.A." At this point I'm ready to yell at my television. First of all, the air is cold because the expansion of a compressed gas is an endothermic process - it draws heat out of the air. This is how your refrigerator and A/C work. Except that those appliances use the energy in the compressed fluid to intentionally cool something. The air motor's primary objective is to provide mechanical energy at the shaft. Any cooling effect of the exhaust air is mechanical INEFFICIANCY - it's energy that does not go towards moving the car. As far as cooling L.A.? Let's look back at the compressor that filled the car's tanks. Remember how most if the electricity (from power plants that dump waste heat) it uses is turned into heat?
Okay, so we've gone from deceptive propaganda to bad narrow-minded science. It seems that your show will now tell me that I can air-condition my house by leaving the refrigerator door open, ignoring the fact that the refrigerator would actually have a net heating effect.
Finally, your show goes from being misleading and telling little lies to downright heresy: the narrator suggests that, since the air motor also works as a compressor, the car could drive around and fill it's own tanks, becoming a, wait for it, perpetual motion machine!
Discovery Channel - you just lost a big fan. I watch your channels for educational value. I've learned a lot, and hopefully it was all true. However, you are doing your viewers a HUGE disservice by airing such rubbish. I think you would do better by airing foul language and geriatric nudity. The United States is already losing our technical edge. When I went to engineering school, certain disciplines had more Asian and Indian students than Americans. They were, for the most part, industrious and outstanding students. Many of them return to their home countries to practice engineering and science for foreign companies. Enrollment of American students into scientific and engineering studies is on the decline. Our school system has dismal minimum requirements in math and science. We need to get people interested in science or we will cease to be a leader in emerging and critically important technologies. I viewed the Discovery Channel is a very positive thing: it brings science into the average American living room and makes it look interesting and fun. Hopefully it has played a role in inspiring a high school student to take an AP science course, or apply for engineering school. Your responsibility is no doubt to your bottom line. However, it is irresponsible and even harmful to support ridiculous false notions with your programming, under the pretense that you are providing a scientific look at technology. We need people to get excited about science so that another generation can be even better equipped to solve critical problems in the world. Airing bad science will only quench the interest and hurt the situation. Shame on you.
Your VERY disappointed, offended, and formerly faithful viewer, JG Burnsville, MN
This message has been edited. Last edited by: mn_nerd,
If you watch the clip closely, I don't think the French inventor intended that it be a perpetual motion machine, it was just the narrator's suggestion. It seemed that a larger air tank was supposed to fill a smaller one (on the car) from the clip, but the narrator didn't mention anything specific about that.
I'm also pretty sure that some engineers capable of building a piston engine would know that they couldn't get energy from nothing. It was just the narrator (or the over enthusiastic script writers) that made the outrageous suggestion.
Much of France's energy comes from nuclear energy anyways, so the transfer of pollution from individual car engines to large plants wouldn't be that big of a problem (if it is one at all).
I agree that it is ironic that of all places, you would see such a blatant violation of the laws of physics on a Discovery channel show. However, given the number of people who responded to this post, I'd say that this technical slip up isn't a big issue. What's more important is that people who saw the show learned something from it or became interested in the future of car technology. The number of people who benefited from watching the show is certainly more than those who were upset by its technical inconsistencies, and even if you are upset about it, you could still probably find something to like about the show.
Why so bitter? Just beacuse someones "theory" seems really out there and impossible doesn't mean that you should get your panties in a twist.
Yes we all know perpetual energy or a machine that performs it is something impossible, but when an inventor/engineer says something of this nature it has to be taken with a grain of salt(much like these forums).
when I am told that this mechanical device is a perpetual motion device, I of course will be a bit skeptical. Furthermore since I know it is impossilbe to have something that is 100% effecient or more. I come to a conclusion, that a: person telling me this information is using it as a relative term. or B: is full of it.
In our case it is being used as relative, a car that is powered by compressed air that can be "energized" by something that itself runs on air could be considered a "high effeciency" loop. This loop, although not perpetual it just shows how concentric peoples thinking are. What I mean by that is, when a person is designing an engine that runs on air, why not make a generator that also runs off air? Thus with their "circle" of inventions they all interact and act as a total system.
To be totally fair, any device that allows for braking effort to be used to generate more power needed to go back up the hill should be considered an energy saving device. Perhaps a compressor could be engaged while going downhill and recoup some of this otherwise wasted energy. Or, perhaps it would add so much additional weight that it would be impracticable. An electric traction motor that can ALSO be a generator and already attached to the drive mechanism is, of course, the best option. Perpetual motion? Impossible. I'm still waiting for that tiny nuclear power plant for an electric car, though, but I'm not holding my breath.
In response to engineer11, my panties are not in a bunch at all, I just think the producers of a channel that earns its keep with technical content should hire technical people to check facts. The impressions given by that segment were inaccurate, and that is irresponsible.
An engineer is a person who should specialize in practical application of science. This is different than being a scientist. By your screen name, I would assume you know this. The French "engineer" in the segment refused to acknowledge some real issues and sounded more like an amateur scientist. Of course the car should compress air during braking to add efficiency. The show clearly stated that it might be possible for the car to do enough of that to run continuously. That is simply impossible.
France gets a tremendous amount of electricity from nuclear power (Attention U.S. policy-makers) and even uses breeder reactors to process waste. That's great. If they use that electricity to compress the air it is essentially a clean car. In most countries, however, most power is from fossil fuel sources. The show simply did not discuss the supply side of the equation, which in my opinion is the more important question. In this case, compressing air is a terribly inefficient process.
The supply side is almost always the more important side. Look at hybrid cars. Do you think someone would be willing to pay $25K for a cramped Prius compact car if gasoline cost $1/gallon? At $2.50/gallon they are selling like hotcakes. Remember all of the excitement about hydrogen cars a few years ago? At that time the vehicle was the technical hurdle. Since then the fuel cell has come down in price by an order of magnitude and the other subsystems are theoretically viable. The supply side, however, is nonexistant.
The segment made some seriously erroneous statements. Perhaps even worse, they were guilty of errors of omission by not even mentioning the cost to compress air. The segment could have been just as interesting with real facts and a better explaination of the regenerative braking.
plese reply to this if you know alot about this feld. I have an idea and i dont care if i get credit for it or not i bet it's alredy been thought of so on with.
perpetual motion is very imposible yes, BUT. what if you could get something that is very close to that. say something around 50-75% effective, let me expalain.
hydrogen cars are very efficient yes. but the exaust is water, and yet 66% of a water molecue is hydrogen, and the other 30% is oxygen. when those to combine in the right environment i.e. Fule cell, they conduct electicity. so right. then when they combine. whala Water, clean distiled. so why not reuse this water, why not store it in a tank so that we can use it later with out it being poluted with things such as asphalt.
or better yet. lets keep the cycle compleatly in side the car, on 2057 they said that some scientist where trying to develop more powerfull/eficient solar energy.
you need electrisity to split water, why not use this new clean more eficient solar panels to encompany our water tanks with spliting technology and feed the oxygen in one tank and the hydrogen in another. the extra energy that we'll be using will solely come from the solar cells.
the hydrogen car cycle summed up
fill up the car with water, during the day the car will fill its h2, O tanks up, you drive it - refilling the water tank witch on a sunny day will refill the hydrogen tank.
not perpetual but almost the next best thing. now get started making this.
i want it out by 2031, cuz the only resion i'm sending this out is because it needs to get done.
Its a shame and a wonder - the cleanest fuel on the planet is also the most costly to make. Electrolysis of water to get hydrogen is extremely inefficient - so much so that stripping Hydrogen from natural gas, or in the process of making other fuels, is ten times cheaper.
True, in a market of scale, cheap solar panels would make it fairly cheap to produce, but you're still losing energy, but the modern fuel cell is very inefficient. Say you already had a bank of charged batteries in your garage. Use them to recharge batteries in an electric car. Now use the same batteries with the same amount of charge to make hydrogen for a fuel cell powered electric car. The only difference is the batteries in one, and the fuel cell in the other. The battery-powered car will go a hundred times further than the fuel cell car.
No matter how good technology gets, the transfer of energy (charging batteries) will always be more efficient than converting energy to something else - like hydrogen. And in the above scenario, you convert the energy twice - from electricity to hydrogen, and back again in the car.
My main point is, better batteries and solar electric panels would go a LONG way toward a cleaner Earth, a lot more than Hydrogen from electrolysis. If you have the electricity, a vehicle that can store it directly is more efficient by a long shot than making H2 and using it. Hydrogen from other sources is less costly, right now, than solar electric power, but those other sources are all fossil fuels - coal, oil, and natural gas. There is a tiny percentage that could be obtained from biomass sources, but that has not been developed and is still in the experimental or home-grown stage.
A breakthrough in the hydrolysis or water would be an earth moving event. Lets pray for that!
This may sound very, very stupid, but consider it...No fuel... with a way that i thought of in two minutes could change the world for centuries to come. Attach two or more electric generators(of the same kind)that produce more energy than needed, to each other so one could power the other with very little electricity to start with. Then you could harness the excess electricity to power the car. Using no fuel what so ever.
If perpetual motion is impossible then how come the earth has been kept orbiting the sun this long?
Further, how come the atom that comprises matter retains its structure with electrons orbiting nuclei and doing perpetual work against the "nuclear forces" like forever? Some tell us that the material of the earth is some 5 billion years old and counting.
This is not to suggest that I support the air fuelled car as a perpetual motion machine since the source though large is consumable like many others: gasoline, hydropower, nuclear energy, solar energy etc.
The gravity field of an object is however a source of infinite energy and a device can be built harnessing this energy for perpetual work or motion.
Its amazing how the words PERPETUAL MOTION can send a sceptic into a frenzy. The narrator said the term but the frenchmens idea runs on compressed air. I have in fact improved upon his idea. My design is not perpetualy motivated but self-sustaining and I plan to drive a vehicle from seattle to new york without refueling of any kind.
"Perpetual motion", in this context, refers to attempts to design an engine system with over 100% efficiency. That would be a self-contained, closed mechanical system that could move stuff and also regenerate enough energy for itself to keep the system operating indefinitely.
Due to some inconvenient laws of physics, efficiency greater than 100% is impossible.
As a consequence, any system running continually can't be a closed system: it needs to have energy added to keep going.
Now, to get back to the compressed-air car: that idea doesn't claim to be a self-sufficient system, so there's nothing scientifically shocking about it!
I imagine that the French developers will be embarrassed to hear the narrator's suggestion about a car that would power itself indefinitely. It's a ridiculous suggestion, and it isn't what they're proposing!
I'm disappointed to find a seemingly fact-oriented Discovery Channel program that changes course at the end and promotes science mythology!
This "future car" show has got to be the most irresponsible piece of programming on TV. Especially the compressed air segment. Maybe the program misrepresented the builder/inventor of this car. First of all, perpetual motion has been attempted many times over the years. So far it has proven to be impossible.
Some of you have voiced your ideas about generators that produce more energy than needed (maybe you were joking, I can't tell) and such. Hey those are good ideas, completely pie in the sky, not to mention impossible. Whenever you find a generator that produces more energy than it consumes, please let the rest of the world know.
Now that I have read a few other entries, I feel better. It seems that many of you understand that this show is full of misinformation. Misinformation that is going to lead the general, misinformed public, to believe that the scientific community is purposely preventing the world from using all this free perpetual energy. I couldn't believe my eyes during the "compressed air" segement when they flashed text on the screen that said it costs $0.00 to operate a compressed air car. Unbelievable. Then, later, the narrator actually admits that it does cost a little to produce the compressed air. I find it very hard to believe that the compressed air car has a range of 200 miles. Those tanks must be running at some serious pressure.
I just find it very irresponsible for such a reputatable channel to run a show with such bad information. It wasn't just a couple of incorrect words or numbers. It was a long discussion full bad information.
The point is that the overall cost of transport will be cheaper.
Whilst compressing air might be inefficient in energy terms, it should nonetheless be cheaper than gasoline -- bear in mind the cost in dollar and energy terms of prospecting, drilling, refining, and transporting the stuff.
Also it should be reminded that an internal combustion engine itself essentially works by air pressure and arguably is more wasteful than something that works purely by compressed air. The whole part involving the heating up of air and spewing out of byproducts are taken out of the system.
Finally, with advances in solar and wind technology, the cost of compressing air and running the car should drop further over time.
Sure nobody is creating energy out of thin air but this approach makes use of abundant, free energy that is all around, and will bring an end to the era of big oil.
Aargh! What was discovery thinking with this one? Can they not get a fact checker or at least someone who has a clue about physics to proof their programmes? I found myself highly annoyed. The big problem for me is that I work on a ship and this is one of the pre-recorded shows which play repetitively on one of the TV channels.
Will the producer or narrator please explain themselves on this forum? You guys have really disappointed a big fan.
