Posted by Rod on December 7, 2008, 4:56 pm
John Nagelson wrote:
>> John Nagelson wrote:
>>> Not so great with wind-generated energy is the fact that you need a
>>> battery bank, and batteries are expensive.
>>> So why not store the energy as gravitational potential energy?
>>> E.g. make the generated energy lift a large weight, controlled in such
>>> a way that it falls when you need it to, yielding just the amount of
>>> electrical power you need?
>> They already use water as the large weight, is anything practical?
>> Just over 1kWh from 4 tonnes lifted 100m (excluding losses).
>
> True that (mass) x (g) x (height) = (required power) x (time) gives
> large figures for (mass) x (height).
>
> But maybe with concrete or old cars?
> Or maybe store some as elastic potential energy?
> I'm only thinking about at a domestic level.
>
> John
Getting four tonnes of material isn't a problem.
But what mechanism have you got that would raise that four tonnes 100
metres straight up?
Or 40 tonnes 10 metres?
Or 400 tonnes one metre?
The raising and lowering has to be a) safe; b) controlled; c) connected
to some sort of generator.
And all that for a measly 1 kWh.
Maybe if you had an arrangement which used your whole house as the
weight? But the cost of making it (in financial and resources terms)
would be prohibitive.
--
Rod
Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
<www.thyromind.info> <www.thyroiduk.org> <www.altsupportthyroid.org>
Posted by Andy Burns on December 7, 2008, 5:09 pm
Rod wrote:
> But what mechanism have you got that would raise that four tonnes 100
> metres straight up?
I haven't got one, I was just pointing out the scale of the problem
> And all that for a measly 1 kWh.
Exactly.
Posted by PCPaul on December 8, 2008, 8:25 pm
On Sun, 07 Dec 2008 17:09:00 +0000, Andy Burns wrote:
> Rod wrote:
>
>> But what mechanism have you got that would raise that four tonnes 100
>> metres straight up?
>
> I haven't got one, I was just pointing out the scale of the problem
>
>> And all that for a measly 1 kWh.
>
> Exactly.
The only place I've seen this work is in an LED standard lamp - you
manually lift a mildly heavy weight from floor to 5' off the ground, then
it falls slowly while running a generator (through a gearbox) for a
couple of hours.
If you're seriously looking at this sort of thing you need to get your
whole house consumption down from 1kW average (what ours is while
occupied, TV on etc.) to a few hundred watts at most.
Posted by meow2222 on December 7, 2008, 3:42 pm
John Nagelson wrote:
> Not so great with wind-generated energy is the fact that you need a
> battery bank, and batteries are expensive.
a persistant myth
http://www.wiki.diyfaq.org.uk/index.php?title=Lead_acid_battery_construction
> So why not store the energy as gravitational potential energy?
> E.g. make the generated energy lift a large weight, controlled in such
> a way that it falls when you need it to, yielding just the amount of
> electrical power you need?
> ??
> Parts would need replacing far less often than batteries.
> John
how would you arrange gearing? Or would you have it only charge when
half max windspeed were reached, and throw away any extra energy at
higher speeds?
Have you calculated what mass and height you'd use?
NT
Posted by Andy Burns on December 7, 2008, 3:48 pm
meow2222@care2.com wrote:
> Have you calculated what mass and height you'd use?
Fiddle with the numbers in google calculator
http://google.com/search?q= (3675+kg)+*+(9.81+((meters+per+second)+per+second))+*+(100+meters)+in+kilowatt+hours
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>>> Not so great with wind-generated energy is the fact that you need a
>>> battery bank, and batteries are expensive.
>>> So why not store the energy as gravitational potential energy?
>>> E.g. make the generated energy lift a large weight, controlled in such
>>> a way that it falls when you need it to, yielding just the amount of
>>> electrical power you need?
>> They already use water as the large weight, is anything practical?
>> Just over 1kWh from 4 tonnes lifted 100m (excluding losses).
>
> True that (mass) x (g) x (height) = (required power) x (time) gives
> large figures for (mass) x (height).
>
> But maybe with concrete or old cars?
> Or maybe store some as elastic potential energy?
> I'm only thinking about at a domestic level.
>
> John