Blades, Air and Automobiles

Electricity is a huge waste of everything. When it is produced, you are very lucky to convert 40% of the available fuel energy into electricity. And transmitting the stuff in power lines incurs losses of somewhere between 5 and 10%.


And then, at the other end, we have inefficient appliances hell-bent on wasting this attenuated stream of energy, such as fridges that work hard 24-7 to cool down nothing more than air, and TVs and computers which burn more energy turned “off” than when they are actually being used.

Electricity is, in short, a ridiculously dumb way for a civilisation to move its energy around. And now we are using it to move our cars. Yes, I know that electric cars are somewhat better than gasoline ones, but only in the sense that the pollution created to make the car go is moved to somewhere else, namely from the car’s engine to a remote power station.

You could argue that electricity can be produced from renewable sources, but we all know that the vast majority isn’t and isn’t likely to be.

So here’s my solution. Usually we convert mechanical energy (such as from a wind turbine) into electrical and then back into mechanical to make something move. Well let’s just skip the middle step, and run our next-generation cars on something that isn’t electricity.

air-car.jpgThis baby is the MDI air car, also known as the MiniCAT. Its power source is a tank of compressed air, pressurised to 300 atmospheres. When the air is slowly released it turns the engine and makes the car go. And that’s it – clockwork, but with air acting as the spring.

This car is also much lighter than a regular car because the engine doesn’t get hot and metals with lower melting points, such as aluminium, can be used in its construction.

This is all fine, but now here comes the smart part. By using the mechanical energy of a wind turbine or water wheel to compress our air directly, we can drive our car from mechanical energy only. And by skipping the conversion to electricity we make big energy savings and remove the need for generators, transmission and storage.

This car can travel 150km or more on a single full tank of air, and the tanks, incidentally, are the same ones used by buses to store liquid natural gas, so they are safe and tested. If you can’t see the obvious advantages of a car powered by air, then I suggest you leave the room right now.

As far as I can see, nobody else has proposed this combination of compressed air cars and mechanical energy. If you know of somebody who has then please let me know.

And if anybody has a wad of cash burning a hole in their pocket and would like to fund me to investigate this system properly, then my ears (and my pockets) are wide open and ready for business.

You know, I think we’ll call it the paddy-wagon…

/ paddy

15 thoughts on “Blades, Air and Automobiles

  1. That is badass. I want me one.

    If Mr G up there and I had the money we’d finance you.

    Unfortunately, we don’t.

    And all I can think is that some people would still want stupid huge SUVs and when they hit an aluminium car…

  2. Hey Paddy, I don’t think storing energy as compressed air is any more efficient than storing it in batteries. Lighter, maybe. Although I like this:

    “The temperature of the exhaust is between 0 and 15 degrees below zero and can be used for air conditioning of the car.”

  3. Where do you get “such as fridges that work hard 24-7 to cool down nothing more than air [this is a fridge left open?], and TVs and computers which burn more energy turned “off” than when they are actually being used?”

    The avoided energy conversions losses for your mechanical system are around 15% at worse no? How efficient is compressed air for energy storage? Although as compared to batteries, lighter weight and presumably better for the environment compressed air systems have some advantages.

    Electric cars don’t just move the pollution, because power plants are more than 25-30% efficient (as cars are) and have the room and money for advanced emissions controls. Not only that, but if they are renewable, they are much cleaner. Even dirty US coal is shown to be marginally cleaner than a gasoline car and costs about 1/3 as much per unit distance. Finally, mass use of electric cars plugged into the grid provides extra capacity and storage distributed widely.

  4. Chris: Not storing it, no – but by avoiding the intermediate step of converting to and from electricity, there will be substantial savings. This was my main point.

    Damon: With fridges I mean fridges that are far too large, encouraging us to stockpile food, and are mostly empty a lot of the time. And every time a big fridge is opened, a big volume of air must be re-cooled.

    TVs and computers, if left on in standby, use more energy in total than when they are used. Because if a TV is used 2 hours a day, it is on standby 22 hours a day, even if it is only a few tens of watts.

    As I say, I don’t know much about the mechanics of the system, but it seems to me that avoiding the cost, complexity and losses of an intermediate electrical step might be worth looking at.

    Good point about electric cars. You are right, they are better. But still not great.

  5. Just back from northern China, I am pleased to be able to report that the Chinese have at least gotten two things right environmentwise.

    1. Low-energy lightbulb acceptance is suddenly extremely high, making me wonder if it might be due to some edict from on high.

    2. Combustion mopeds are forbidden. People whizz around on silent and scary electrical ones.

    In other news, my dad explained the riddle of the SUV to me the other day. I asked him why on earth anyone would want to buy one. He told me that suburban soccer moms feel safer in a heavily built car where they sit above the level of normal cars. They’re basically just protecting their brood.

    Paddy, please write an entry on the likely future of passenger air traffic. When will the average Joe no longer be able to afford air tickets? Will governments agree on a CO2 emissions tax to this end?

  6. I’m disappointed in you, son. Haven’t I explained to you that cars are wicked? They honk! They maim! They get in your way!

    A fumeless PaddMobile may get you excused from the innermost circle, but, mark my words, you’re headed southward.

  7. Martin: Bloody soccer mums… And yes, I will expound at length about air travel in the near future. Watch this space.

    Tor: Yes cars suck. But occasionally I need to drive something big home from IKEA and I don’t have a horse, so what’s a man gonna do?

  8. Yes cars have legitimate uses. But if their use were restricted to cases where they’re actually needed, we could run them on baby fat and still be better off morally than we are today. No amount of “green technology” is going to make mass car commuting a good idea. Habits are going to have to change, and I tend to think that snazzy techno-fix proposals risk turning people’s attention away from that fact.

  9. Tor: I agree absolutely. Green cars are pretty pointless – but I suspect that we are always going have the damned machines, whatever I think about them. Hoping that people will suddenly change just isn’t going to work, is it? So either we accept that we are screwed, or we offer the scrambling masses something better.

    And we can also take out the world’s media and shoot them against a wall.

  10. You have a point, I’ll admit. Then again, the more dependent a car is on gasoline, the sooner we’ll be rid of it once oil becomes a scarcity. I note with satisfaction that Sweden has heavier and thirstier cars than any other EU country. Hee hee.

  11. How about HPV-electric or HPS-air hybrids? See my Traix idea at my blog. (The pics aren’t connected though)

    Traix link<

    Human pedal + electric or air power to equal supplement the pedaling, then add superb aerodynamics and attachability to make singles into multi-unit trams for efficient mass transit, and resulting better health.

    There is no better answer, at least in the next 20 years IMO.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s