Chevy Volt arithmetic - why I won't be buying one

[Carl]

I am not into physics or all that smart but there are two major problems with compressed air except for perhaps as DAT mentioned,tapping already available resources.

The first would be the economics of it...compressing air is all about resistance.
You are literally putting 50 lbs of crap into a 5 lb bag and that takes a lot of effort to achieve.

The second problem I see is heat.
Compressing air makes the molecules collide and the friction creates a large amount of heat,it is what allows a diesel engine to run without an external means of igniting the fuel.
The sizable storage tanks (really another problem as now you are adding weight) and plumbing from the compressor would be hot enough to set the vehicle on fire I would think.

Correct me if I am wrong.

[USA4ME]

Great thread!  It's amazing (yet completely unsurprising) how many of the primitives don't have a clue as to how and properly evaluate a financial decision.  The primitives Motown_Johnny, KittyWampus, bluestate10, lumberjack_jeff, madinmaryland, and several others clearly demonstrate why they live from hand-to-mouth, with the likelyhood of that ever changing for them being improbable.

.

[GOBUCKS]

I am not into physics or all that smart

See. You should have paid attention in class, like nadinbrzhzhzhzhski.

[TVDOC]

I am not into physics or all that smart but there are two major problems with compressed air except for perhaps as DAT mentioned,tapping already available resources.

The first would be the economics of it...compressing air is all about resistance.
You are literally putting 50 lbs of crap into a 5 lb bag and that takes a lot of effort to achieve.

The second problem I see is heat.
Compressing air makes the molecules collide and the friction creates a large amount of heat,it is what allows a diesel engine to run without an external means of igniting the fuel.
The sizable storage tanks (really another problem as now you are adding weight) and plumbing from the compressor would be hot enough to set the vehicle on fire I would think.

Correct me if I am wrong.

Actually, all the discussion about "alternative energy", etc. is just a bunch of compressed air (to coin a phrase).......

The entire issue of total transportation fuel efficiency boils down to one simple concept:

"Energy budget".....is the technical term, translated it simply means that you need a fuel that:

provides more energy in its usage than it consumes to create.........

Simple concept........and there is only one viable option that meets this criteria at present technology levels........petroleum

Why, many would ask is petroleum the only economical motor fuel, with a positive energy budget?  Also simple, because nature has done nearly all of the work, and expended the energy to produce it.

Scientifically, the discussion is over.  the only thing remaining to talk about is how much of the taxpayers hard-earned money is the government willing to squander to make these "alternatives" look like they are competitive, when they really never will be.

doc

[compaqxp]

I had to plug my car into the OP's estimates just to see. I know it's not of much value to anyone but me however, I thought I'd post it.

I drive a small car that is paid off, free and clear. It is worth about $4500 in resale.
I get about 50mpg.

A Volt costs $40,000 (I will use round numbers). Let us assume the net asset cost of a Volt to me is $35,500. I will need
to find $35,500 in fuel cost savings on a net present value basis to justify buying a Volt. This assumes that I don't
finance the vehicle, ie, I have $35K in cash just laying around.

Let us suppose for exposition that the Volt gets 60mpg of actual gas purchased (it runs on gas and electricity). Gas is $5/gal (Canada),
and I drive 25,000 miles per year.

I use 500 gallons of gas per year at an expense of $2,500; with a Volt I would use 416 gallons and spend $2080. That's an
annual gas expense savings of $420.

Assuming that the electricity to feed the car is free to me (a horrible assumption), and there is
no time value of money, it would take 84.5 years to recoup the expense of the vehicle relative to the one I currently own.

Not worth it.

[Wineslob]

The other day a DUmmy, maybe this one, was all excited about development of a free, unlimited energy source: compressed air.

This will NEVER work. How the hell the DUmmies (ya, I know) think it's free, is beyond me.

Think about this, DUmmies, it takes approx 70-80 CFM @ 100 PSI to run a 4.5 H.P air motor. That turns into a compressor requirement of roughly 25 HP that has to be run by something. WTF do you think that would be?

So multiply that by 10 to get a mediocre amount of power...........................uh-oh.............



Every time I think they can't get any DUmmber ( :P ) they don't disappoint.

[Lacarnut]

I have read that the Prius battery pack cost around $2,500. After 7 or 8 years, the value of that vehicle will drop like a rock. However, the Volt's battery pack cost $10,000. GM is not mass producing these suckers in large numbers because of the battery cost. The Volt will turn out to be a lemon and albatross around GM's neck. It will be as big a failure as the Caddy diesel was.

[DumbAss Tanker]

I am not into physics or all that smart but there are two major problems with compressed air except for perhaps as DAT mentioned,tapping already available resources.

The first would be the economics of it...compressing air is all about resistance.
You are literally putting 50 lbs of crap into a 5 lb bag and that takes a lot of effort to achieve.

The second problem I see is heat.
Compressing air makes the molecules collide and the friction creates a large amount of heat,it is what allows a diesel engine to run without an external means of igniting the fuel.
The sizable storage tanks (really another problem as now you are adding weight) and plumbing from the compressor would be hot enough to set the vehicle on fire I would think.

Correct me if I am wrong.

Well, the heat isn't really the limiting factor, but it does come into play.  Onboard compression isn't normally a part of the powerplant on an air engined vehicle, they just use stored air which they have to refill fairly frequentsly. 

Compression does produce a lot of heat, but mainly it's dealt with by adding mass to the compressor to dissipate it.  Adding a big chunk of cast steel for an onboard compressor to a flyweight car kind of defeats the whole purpose, especially if you also have a big-ass air tank sturdy enough to keep a useful amount of air on tap at 25-30 atmospheres in there too.  And as others have noted, the horrifying lack of efficiency in compressing the air and then using it to drive an air motor makes onboard compression a nonstarter.  Compression is noisy as all Hell on top of that, which would be another major problem with having it onboard. 

[GOBUCKS]

A compressed-air car would be an expensive piece of shit, but you could drive nails like crazy.

[Wineslob]

The second problem I see is heat.
Compressing air makes the molecules collide and the friction creates a large amount of heat,it

Yup. Normal output temp for a piston compressor is around 400+ degrees without an aftercooler. A rotary is lower, but still in the 250+ range. (I designed and installed the compressed air system in our 100,000 square foot factory, we use a 100 HP rotary machine capable of 450 CFM)

[GOBUCKS]

I've heard a compressor rule of thumb that they cost about $1 per day per horsepower to run. 

[jukin]

Not only does the air heat up (Heat of Compression) it also gets very wet. That is why systems over 25HP usually have both an after cooler and dryer past the compressor. Water and the corresponding rust is the main cause of tank problems. Right now in kalifornia a propane tank that has no where near the level of moisture has to be traded in every seven years. This is regardless of condition. The tanks in cars would be at much higher pressure (around 4500 PSIG) like dive tanks. They are heavy and if in an accident would be a great missile shooting out a pile up.

As mentioned above, every time you convert a source, you lose energy (entropy, it's a bitch).

It does amuse me to see DUmmys that can barely figure out how velcro works looking into the complexities of energy transfer.

The prius batteries go for about 25k and the replacement cost (2008) was just over $8k. The lithium-ion battery lpant in Canada is so horrendous to the environment that NASA tests the robotic vehicles there.

[Rebel]

I've heard a compressor rule of thumb that they cost about $1 per day per horsepower to run. 

Well, that shoots my suggestion down.

Next suggestion, burn liberals for fuel.

[BlueStateSaint]

Next suggestion, burn liberals for fuel.

Environmental impact statement, Reb . . . 

[ChuckJ]

I'm waiting for the SSP technology to be used in our vehicles.
[youtube=425,350]http://www.youtube.com/watch?v=WZKmoicYhNo&feature=related[/youtube]

[Rebel]

That's what they truly want us in.

[Tucker]

A compressed-air car would be an expensive piece of shit, but you could drive nails like crazy.

What would happen if it were T-bone by a truck and ruptured the holding tank?

[GOBUCKS]

What would happen if it were T-bone by a truck and ruptured the holding tank?

You'd be like Alice Kramden, en route to the moon. Bang! Zoom!

[DumbAss Tanker]

You'd be like Alice Kramden, en route to the moon. Bang! Zoom!

Yeah, you get to find out how it feels to go really, really fast in a 'Green' car.  Briefly.

[DefiantSix]

Yeah, you get to find out how it feels to go really, really fast in a 'Green' car.  Briefly.

Yeah; VERY briefly.  I'd lay odds the (crash test) DUmmies can't take more than about 4 Gs of acceleration before they black out.

[Rebel]

Environmental impact statement, Reb . . . 

I could give a rat's ass about "environmental impact". These dumbass liberals don't seem to understand that that CO2 is what's preventing our planet from becoming an icy ball of dirt.

[BlueStateSaint]

I could give a rat's ass about "environmental impact". These dumbass liberals don't seem to understand that that CO2 is what's preventing our planet from becoming an icy ball of dirt.

I know that, and I really don't give a ****, flying or grounded, about it either.  Just a splash of sarcasm, that's all.

[Rebel]

I know that, and I really don't give a ****, flying or grounded, about it either.  Just a splash of sarcasm, that's all.

I know, man. That would be my response to those morons.