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Berkeley Engineers Have Some Bad News About Air Cars
cheeks5965 writes "We've argued before over compressed air vehicles, a.k.a. air cars. Air cars are an enchanting idea, providing mobility with zero fuel consumption or environmental impacts. The NYTimes' Green Inc. blog reports that the reality is less rosy. New research from UC Berkeley and ICF International puts a period at the end of the discussion, showing that compressed air is a very poor fuel, storing less than 1% of the energy in gasoline; air cars won't get you far, with a range of just 29 miles in typical city driving; and despite appearing green the vehicles are worse for the environment, with twice the carbon footprint as gasoline vehicles, from producing the electricity used to compress the air. Given these barriers, manufacturer claims should definitely be taken with a grain of salt."
How would you compress the air in the first place?
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
There appear to be two primary advanages of these cars: They're cheap to make and they don't directly pollute the city air. If the power plant is downwind they could actually improve the air quality in the city. You also get "free" AC, although heating the car is an issue. Since these are primarily targeted at cities like Mumbai the cooling is more important anyway.
I read the internet for the articles.
and despite appearing green the vehicles are worse for the environment
Compressed air is just a medium in which to store energy. The energy could come from solar panels on your garage. It compresses the air. The air powers you car. Zero emitions.
This is opposed to batteries which really aren't good for the environment, but all those Prius owners don't really seem to care about Lithum strip mines while patting themselves on their backs.
Hydrogen is yet another method of storing energy.
Just compressing air from solar, wind power, etc gives Zero emissions no matter if the efficiency is only 1% or 100%
Perfect idea, we could use more highly flammable compressed material waiting to explode into a fiery ball of death on the roadways.
Not on debunking this, because it's a completely ridiculous idea that anyone who's taken even introductory engineering thermodynamics should be able to debunk. Rather, they should get credit for going the extra mile and actually getting a paper out of the thing (and media attention!).
I mean really. There's perfectly good reasons why we're not using compressed air as a 'fuel', and it's not that we hadn't thought of it. The idea (and applications) have been around since the 19th century.
This is a surprise to someone? Who ever though this *could* work? Certainly not anyone with any knowledge of thermodynamics. The only compressed -gas systems that even have a chance of working are those that store the working fluid as a liquid, meaning it has to be able to be liquified at room temperature at a reasonable pressure (few hundred PSI at most). Otherwise the tanks are huge and heavy (meaning it will barely move under power) or they are small and heavy (meaning it has no range). Two excellent working fluid for this purpose are - wait for it - CO2 and Freon! Oops.
Brett
Sounds like a tech geek's way of looking at it.
Most people would say -- having a sizable amount of compressed air storage in one's house is great all around -- for your pneumatic power tools.
The troll with karma.
As said in great grandparent post, compressed air and hydrogen are energy storage mediums. Wood is the same thing. Trees use solar energy to convert CO2 into carbon. When you burn the wood, you put the CO2 back into the air and get the energy back as heat.
It doesn't matter if we burn the wood for something useful, the trees dies and rots, or the tree is burned in a forest fire: at some point the carbon is coming back out of that tree.
But you could just as easily have that windmill power a turbine to generate electricity to charge the battery in your electric car and get a far higher energy density leading to more mileage per charge and per each day's wind. I think that's the point that's being made. There's lots of clean ways that can generate energy -- any of which can be used to compress air, but why add that extra unnecessary step in the middle when it's just an added inefficiency?
Actually admitting that a "green" energy source may not be as green as they thought. Wish more hybrid owners understood that... that battery must be disposed of eventually. As I understand it, hybrids aren't as green as people think. So much of the "green movement" is a total sham b/c it focuses narrowly on supposed benefits while ignoring reality & even data that contradicts the claims made.
.. the wind does, that is.
Using a mechanical air pump driven by the wind makes massive sense to me, it is patently obvious. This method alone makes air power a win.
How we generate energy now for air cars now makes no sense, is patently stupid. Fossil fuel -> heat energy -> mechanical energy -> electricity over a lossy inefficient grid -> pumping compressed air -> filling up your car.
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
Since when does a conclusive study demonstrating what you already knew was true constitute "bad news"?
Bad news: perpetual motion doesn't exist. Would it be good news if it did exist? With such a toy, an enterprising galaxy could tip the universe toward heat death. Maybe a supernova is just perpetual motion gone Sorcerer's Apprentice.
If you're in a troubled relationship and you finally have a big blow out argument, and one of you storms off into the night, is that bad news, or good news? If you defined keeping the peace as good news, isn't that how you got yourself into that situation in the first place?
Life consists of nested narratives. What's good at an inner level of narrative might be a complete disaster for a containing narrative. Is the discovery of a big new oil field good news or bad news? Good for Exxon, bad for Bangladesh? Good for me, bad for my children?
The one case where I really understand good luck / bad luck was an episode of the Sopranos where Corrado says "these things come in threes". Corrado suffers from a narcissistic sampling bias, and thinks the outcome of his own cancer might complete the trinity of two other deaths. There's half a dozen deaths in every episode, but since Corrado has a deep insight into bad luck that I personally lack, he's able to frame his fear in specific terms.
Bobby's inquiry, "With all due respect Junior, what do you care about the details?" is one of my favourite lines of the whole series. That's not the sentiment of a man dumb enough to marry Tony's psychopathic sister Janice, which is where I started to lose interest in the series. "Hey, let's shack up and double our screen time." Bad news: Bobby just married Janice, and now the show sucks. Actually, I didn't regard that as bad news so much as an unpleasant insight into the law of least redemption in David Chase's fictional hell.
What does "bad news" really mean? How about "I'm about to tell you something you won't like, so please take three deep breaths before pulling out your gun and shooting me"? I think it's a hereditary conversation tick we use to give the recipient's hominid brain an extra moment to distinguish message from messenger, or to give an air-car believer a moment of hesitation before prematurely ending it all.
I thought if you first converted it into ethanol, one pint could power days and days of hard pedalling.
Compressing gasses generates huge amounts of heat, which if not captured, is waste heat. Similarly decompressing gases loses heat - that is why aerosols are cold, and is how refrigeration works. Compressed air as a means of energy storage is a bad idea.