On 18/05/16 17:17, Chris Hogg wrote:
On Wed, 18 May 2016 13:59:31 +0100, Chris Hogg wrote:

On Wed, 18 May 2016 11:45:44 GMT, lid (AnthonyL)
wrote:

Out of curiosity, anyone calculate how many panels
would be needed to lift one ton(ne) in say 6hrs of average light?

To make that question sensible, you'd need to specify the height
you're lifting it to.

Here's a calculation (stepwise, for my benefit, and to allow it to be
torn to shreds by those who can do it better, as I don't believe the
result!).

The upper lake at Dinorwig is a little over 500 metres above the lower
lake, so I'll assume a height of 500 metres.

1 tonne exerts 9806 Newtons of force.

The work done raising 1 tonne by 500 metres is 9806x500 = 4903000
Newton-metres.

A Joule is 1 Newton-metre, so the work done raising 1 tonne by 500
metres is 4903000 Joules.

This is achieved in 6 hrs, or 6x60x60 = 21600 seconds.

Units of power are Joules per second

So the power required is 4903000/21600 = 227 Joules per second.

A Joule per second is a Watt.

So the power required to raise 1 tonne by 500 metres in 6 hours is 227
Watts.

AIUI a typical domestic solar panel delivers 260 Watts at full blast.

So 1 panel should do it, with a little to spare.

I find that hard to believe! Where have I gone wrong?

Seems OK to me. 100 meters an hour is 27mm or a little over an inch a
second.

A human being with a tackle can lift a tonne that fast easy.

In fact an Irish Navvy could shovel and lift 30 tonnes a day back in the
50's.

I think you are encountering the true meaning of 'energy density' - that
a tonne of water up a hill is actually not really that interesting -
maybe a couple of Kwh at best.


--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly