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People are a certain size, air has a certain density, and people want to go
a certain speed, this fixes the constant power a car needs to be able to
produce to around 25 kW. Higher peak values might be needed to get
acceptable acceleration and hill-climbing performance.
People want their car to go a certain distance between being "refueled"
whatever that might mean, that fixes the amount of energy a car needs to
carry onboard to about 1000 MJ.
Now look up the various ways of storing energy:
http://en.wikipedia.org/wiki/Energy_density
Note the "energy density" column, which is how much mass you need to store
that energy. For our 1000 MJ we would need to carry around in our car:
7 kg of liquid hydrogen
22 kg of petrol/diesel
2 tons of flywheel
3 tons of Li-Ion batteries
3000 tons of mechanical spring power
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On Thu, 20 Mar 2008 19:36:04 +0000, St. wrote:
> My electricity and gas prices have soared bigtime recently, as well as
> many
> other things like food, petrol, etc.
We've noticed that around here as well. Our end costs have stayed pretty
much the same as we've recently reinsulated and had our roof redone (and
replaced a 50+ year old boiler with a high-efficiency model), so with all
those upgrades we've kept costs about the same as before, where we
normally would have expected to see our costs drop.
Jim
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