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Re: Feasible new approach to solar power use? - Metal bars thermal

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Posted by azuredu on January 9, 2009, 9:05 pm
 
On Jan 9, 9:10 pm, david.willi...@bayman.org (David Williams) wrote:


No, the problem is not here. It is the difference between force and
energy.

Once expanded, the bar stops moving, and there is no longer energy
output until the next day. Unless you cool it down, but that'll
consume more energy than you get.

Posted by Father Haskell on January 9, 2009, 11:14 pm
 
On Jan 9, 3:10 pm, david.willi...@bayman.org (David Williams) wrote:

Try either nitinol springs or bimetallic strips, same as used in
thermostats.  The coiled bimetallic sensor strip used in cheap
outdoor dial thermometers can move the tip of the needle
several inches in response to a 20 degree temerature change.

Posted by Father Haskell on January 10, 2009, 11:11 pm
 On Jan 9, 10:57 pm, david.willi...@bayman.org (David Williams) wrote:

Use several.

Check these:
http://www.imagesco.com/articles/heatengine/HeatEngine.html


Posted by FKohler on January 11, 2009, 11:43 pm
 
Thank you all for the ideas and critics as well.

Well, in fact, the tiny distance is true. Thats the issue, with the
tradeoff of the enormous force. I was thinking of heating up an
aluminium bar of 10m (thorugh parabolic solar concentrator). Throwing
some figures as an example, if we heat up 300o C (feasible?) we would
have a final expansion of roughly 7cm.

7cm to continuosly turn a simple ratchet wheel day by day (instead of
any gear mechanism) to lift some heavy load (as an "arcaic" but cheap
way to accumulate potential energy until the object is released down).
Of course, depending on the target height it would take 5, 15, 30 days
or more, but having several devices running at the same time (reducing
overall costs as well due to scale) would generate energy in a more
stable and constant output....

In fact, I thought somthin really simple because of the cost of the
whole system, but innefficiency is part of the game as well: steam has
its own innefficy (and still the key source of energy generation...),
as well as stirling, etc. However, dont you think guys this is much
more a matter of total cost x energy generated than efficiency?

Again, thank you all for this discussion. Its awesome to be discussing
such topics (solar energy) and reading different ideas and experiences
in a regular basis, in this group

Best regards

Posted by Mauried on January 12, 2009, 6:07 am
 wrote:


Id start at looking at how much energy is needed to make your
aluminium bar in the first place , and whether you will ever recover
that energy in your lifetime, by expanding and contracting the bar.


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