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The Tata AirPod: a car that runs on compressed air w/150-200km range
- jakeonthemove 14y agoThat's pretty awesome, though I wonder how they achieved that efficiency from simple compressed air (surely a pack of Li-Ion batteries of the same volume would do better?). Regardless, you can compress air yourself all day long using solar panels and/or wind turbines, and even if you use the grid, it'll still come out a lot cheaper...
- _delirium 14y agoThe proposed benefits seem to mainly be in the ease of deploying the recharging infrastructure, not greater efficiency. Here's a paper that's skeptical of the overall efficiency: http://iopscience.iop.org/1748-9326/4/4/044011/fulltext/ http://iopscience.iop.org/1748-9326/4/4/044011/fulltext/
- podperson 14y agoInteresting paper, and it suggests some other possibilities, including a Pneumatic/Combustion hybrid (i.e. using a compressed air "flywheel") which seems to have greater benefits than an Electric/Combustion hybrid (a tank of compressed air is lighter than batteries). Perhaps Tata is experimenting with an electric/pneumatic hybrid (so electric, but compresses air when braking, and consumes it when accelerating). This might work, but doesn't help with infrastructure rollout.
- masklinn 14y ago> a tank of compressed air is lighter than batteries Joule for joule, it's not. The best compressed air tanks you'll find roughly reach lead/acid batteries in energy/weight (~100kJ/kg). Lithium-Ion batteries have 4 to 9 times the energy density.
- podperson 14y agoIndeed. Also the mechanism to capture compressed air when braking would be in addition to the electric motor, which is needed in any event, and can charge batteries when braking. So yeah, upon reflection, just a Bad Idea.
- nsxwolf 14y agoMechanical simplicity and no expensive batteries are pluses.
- typicalrunt 14y agoI agree with you, to a point. I wonder about the mechanical simplicity of having air drive pistons in the engine. It's yet another point of failure and, while similar to combustion engines, is there no other way to have compressed air drive a car other than with a piston engine? I'm probably being naive here...I have no knowledge on this subject.
- ajcarpy2005 14y agoYou could use a Quasi-Turbine. http://www.howstuffworks.com/quasiturbine.htm http://www.howstuffworks.com/quasiturbine.htm
- kragen 14y agoThere are a lot of different ways to have high-pressure gas push solid objects around. Piston engines, turbines, and rockets are the three most common, but there are also Wankel engines, rotary vane motors, and more exotic designs like the Quasiturbine and the dozen or so other kinds of positive-displacement pumps.
- debacle 14y agoIt looks like this is getting completely owned by HN. Does anyone have a mirror?
- deleted 14y ago[deleted]
- andypants 14y agoI doubt it, it's hosted on tumblr. It handles far more traffic than HN.
- deleted 14y ago[deleted]
- typicalrunt 14y agoI love this idea, especially for short city-style commutes. The price ($10k) is good enough that it's under my impulse buying threshold for cars. My only worry (confusion?) is if I brought this car into a small town and the car runs out of air, where can I fill it up? Can I just go to any car-repair shop that has a compressed air line (e.g. for hydraulics) and use their equipment?
- arethuza 14y agoWhat would be interesting is if it could carry a small electrically powered compressor that you could plug in for emergencies.
- ajcarpy2005 14y agoI think this is exactly what the electric motor does: compress the air if you run low.
- jherdman 14y ago> The price ($10k) is good enough that it's under my impulse buying threshold for cars. I'm not even sure where to start with this.
- qq66 14y agoNot really that weird at all. Cars maintain a healthy resale market so if you buy a car with a couple of owners and a lot of miles for $8,000 and drive it for a few months, you can often sell it for the same, or just a little less, than you paid for it. It's not an $8,000 gamble, it's more like a $500 gamble.
- aakil 14y agoThese would be great for city travel. The two main issues would be safety and parking. They'd have to make a strong case for the vehicle being safe in the case of an accident, not unlike the challenge the Smart Car had. For the issue of parking it would be unlikely that a city would set aside real estate just for these cars as they'd have to do it all over the city and it would be relatively expensive. I think a better solution would be a car-sharing one like Zip Cars. I can pay a monthly fee to have access to the cars at certain spots and if I want to leave in rush hour, I'd pay a premium, or something to that extent. It's a really interesting idea, I live in NYC and I'd love it here.
- GFischer 14y agoI hope this works - a compressed-air bike design from here (Uruguay) from 2005 failed to be funded, probably because the inventor was a bit of the crackpot type, but it did work. http://www.practicalenvironmentalist.com/eco-gadgets/air-bike-shoots-around-for-15-miles-per-penny-but-unfortunately-looks-kooky-and-dangerous.htm http://www.practicalenvironmentalist.com/eco-gadgets/air-bik... http://www.youtube.com/watch?v=05kQHmXfcQw http://www.youtube.com/watch?v=05kQHmXfcQw
- mrspandex 14y ago> a city car running on compressed air (as well as a battery-powered electric motor) The range sounds implausible to me at any reasonable speed on compressed air alone. How is the electric motor involved? Is the air a backup for the battery or vice-versa?
- anovikov 14y agothis is a scam which has been explained a lot of time. energy storage density of compressed air is extremely small and will be enough for only a few miles of range, no way for improvement here, and efficiency is very, very low, way lower than batteries because of the energy inevitably lost when the gas heats due to compression, then dissipates heat. forget it.
- peteretep 14y agoAnd yet Tata are a huge, well-known international. If they say they have an air-powered car, they have an air-powered car. This isn't just some dude in their garage.
- rglovejoy 14y agoSo what if it's Tata? They may be a huge, well-known multinational, but the laws of thermodynamics apply to them too.
- masklinn 14y agoThe car apparently also has an electric engine. Did tata actually say the car ran on compressed air for the range specified in TFA, or is it just TFAA bullshitting? Because AFAIK the effective energy density of CAES (Compressed Air Energy Storage) is 40~100kJ/kg depending on the tank material, with variable pressure. The upper range is roughly that of a standard lead-acid battery (except the battery has roughly constant voltage) and it gets completely blown away by e.g. li-ion (360~900kJ/kg)
- anovikov 14y agoworse than that, 'charge-discharge' efficiency is terrible compared to any kind of battery. it won't save any energy vs conventional car as measured in well-to-wheel efficiency.
- masklinn 14y agoYes absolutely, I wasn't putting that in because the case was damning enough without involving the energy loss in charging the thing. Though the comments suggesting the electric engine is a compressor to "refill" the bottles on the go could need that reality check.
- forgottenpaswrd 14y agoIt looks lame, like the Segway. This seems to be the official teletubbie's car. People wants something more akin a kiss ass compress air-electric kart to move in the city. Something simple, that does its job well, and fast when you need to accelerate in a hurry. Cars are empty in the cities most of the time, make them unipersonal.
- codegeek 14y ago"Something simple, that does its job well" Exactly. And isnt it what this thing is trying to do ?
- jgrahamc 14y agoThe company behind this invention has been talking about the roll out of these cars for many, many years (http://en.wikipedia.org/wiki/Motor_Development_International http://en.wikipedia.org/wiki/Motor_Development_International). And this particular blog post doesn't give any details of when Tata is going to actually produce a car. I recall a long time ago that these cars were going to be introduced in Mexico (that was one of many things that didn't happen). Wikipedia has good articles on compressed-air engines and cars. Here: http://en.wikipedia.org/wiki/Air_engine#Automotive http://en.wikipedia.org/wiki/Air_engine#Automotive and http://en.wikipedia.org/wiki/Compressed-air_vehicle http://en.wikipedia.org/wiki/Compressed-air_vehicle Tata has been a licensee of the technology since 2007 (http://www.gizmag.com/tata-motors-air-car-mdi/22447/ http://www.gizmag.com/tata-motors-air-car-mdi/22447/). When they go into production it will be interesting news.
- ChuckMcM 14y agoThis. So back in 2007 I saw that Tata had licensed the technology for using the air-motor in its cars. As an infrastructure guy I thought "Hmmm, if this stuff works, I could use it in a data center." So I tried to do that. Here was the plan, using a windmill you could compress air, it's a pretty simple mechanical linkage, run a pump off the rotating vanes, has been done for hundreds if not thousands of years. But instead of water, you pump air into tanks. This generates heat because you are compressing the air of course but its windy so you've got heat sink vanes in the air flow being cooled by convection. Now at some point your data center wants a bit more juice, so you dump air through these MDI engines, which are running electrical generators. But here is the thing, when you dump the air it gets colder, a lot colder and the pipes can freeze up, but this is a datacenter and you run the pipes through the data center and cool it epic win! Power and cooling for free, the more power you use the more cooling you get, how neat is that?! Except there was no amount of money I could give MDI in exchange for engines. They don't make the engines, they don't have a plan to make the engines, they won't let someone build the engines and sell them at a profit because they won't license them to do so. I was a classic case of an inventor being so unrealistic about what the value of their invention is, they prohibit the creation of a market around it. The trick is that markets have choices, and an air engine would be a good choice, but not if it is not cost competitive with high efficiency diesel, or cheap (and dirty) two stroke gas engines. After I gave up (by mid 2008) trying to get them to see the error of their ways I figured it would be 20 years until we saw a credible use of this technology because all the patents would finally expire, and people would start to make them, and probably curse the folks at MDI for their short sightedness.
- PonyGumbo 14y agoThese have been cooking for a long time. I was on the MDI mailing list back in 2000/2001 when they were supposedly coming to market the following year. It's cool to finally see them in production - I thought it might never happen.
- fpp 14y agoGreat when they finally will start mass producing this technology - perfect for large cities in India, Argentina and Brazil e.a where already lots of small vehicles run on compressed natural gas (CNG). BTW - This story has been all over the I-Net the last days (again). A link to the actual manufacturer / technology company behind that. http://www.mdi.lu/english/ http://www.mdi.lu/english/ If such energy storage technology becomes available at low prices lots of additional "synergies" can be envisioned - e.g decentralized & cheap storage for small solar power (e.g. 50KW) - seen some DYI solutions for that with compressed air - overall the issue with compressed air storage is the low energy density.
- ars 14y agoCNG and compressed air are quite different. One burns to provide energy, the compression is just for storage. The other uses the compressed air as the power source. They are not interchangeable, and having one doesn't help you with the other since the pressures are so different.
- z92 14y agoI wish they published energy storage capacity in KW-hr. Theoretically a car can run for infinite distance once it has been accelerated to its desired speed.
- mpyne 14y agoNo, a car can't run for infinite distance even once at its final speed, unless you're talking about the kind of theory that doesn't involve friction, drivetrain losses, aerodynamic resistance, or even things as simple as having a radio turned on (not to mention headlights)
- eavc 14y agoYou forgot to account for the ramjet.
- z92 14y agoSure. These are practical things. And practically it can't.
- vibragiel 14y agoFriction forces have been core theoretical concepts since many centuries.
- deleted 14y ago[deleted]
- HeyLaughingBoy 14y agoFriction, mechanical losses and drag aren't concepts covered by physics theory? Guess I must have been asleep during my Dynamics classes...
- starpilot 14y agoTheoretically an electric circuit can operate with zero heat output using perfect conductors.
- podperson 14y agoLeaving aside the laws of thermodynamics, well-to-wheel efficiency, etc. Imagine getting stuck in traffic in such a car. What powers the A/C?
- giardini 14y agoThat's easy - the expanding gas! Releasing pressurized gas absorbs heat so simply running the released gas through a set of A/C coils would provide indirect A/C or you could merely vent the "exhaust" (it is air, after all) into the passenger compartment since that "exhaust" should be very cold.
- podperson 14y agoIt's a cute answer, but very inefficient. You're throwing away the mechanical energy. Also bear in mind that "refueling" with compressed air will heat up your car.
- rfugger 14y agoThe system overall may be inefficient, but using the cold exhaust from the engine as A/C doesn't make it any more inefficient.
- kragen 14y agoIn fact, if the air conditioner coils are between the air tank and the engine, the air conditioner could make it more efficient, if you don't have some other kind of regenerator-in-a-dewar trick going on.
- ars 14y ago> You're throwing away the mechanical energy. No you are not. The waste gas vented from the system is very cold, using it as A/C costs nothing. Although if you are sitting in traffic you are not moving, and have no waste gas.
- ams6110 14y ago
- Refefer 14y agoWhat happens in a car accident? I can't imagine the sudden expulsion of all that compressed air is going to act like anything other than a small bomb going off.
- masklinn 14y agoSome sort of quick-release valve as with LPG? Not sure it's sufficient considering the kind of pressure you'll need in the tank to store an amount of energy worth using.
- ars 14y agoIt's not hard to make a tank like that strong enough for a car accident. It already needs to be very strong just to handle the pressure.
- jimgardener 14y agosearch http://www.tatamotors.com/search.php?query=airpod http://www.tatamotors.com/search.php?query=airpod shows 0 results !!