On 05/30/2016 06:11 PM, mix...@bigpond.com wrote:
In reply to Stephen A. Lawrence's message of Mon, 30 May 2016 12:57:15 -0400:
Hi,
[snip]
Right, for sure, but seriously, anybody who watched Space Angel as a kid
knows you can't just let a solar mirror point anyplace it wants --
you're just asking to have your headquarters burned to a crisp while the
bad guys escape.
As I said to start with, you don't really need to point them all at the
ground. Just deflect them a degree or so off target, each mirror going
someplace random -- that shouldn't take much energy, and is probably
something you could do with distributed backup power.
Actually, this can be problematic too, as the reflected light can temporarily
blind pilots, posing an air safety hazard.
Um ... good point. A single 30 foot mirror still packs quite a punch.
OTOH it's still better than accidentally hitting it with the whole
focussed output of the mirror field. That be like a beetle under a
foot-wide Fresnel lens -- popcorn airplane.
In any case, in the scenario which actually happened there wasn't any
lightning strike, power wasn't lost, and it was a lot more like the
meltdown at Chernobyl, where the technicians intentionally put the thing
into a bad state for testing and then bad stuff happened. If the thing
had a 'defocussed' mode one could even imagine spotting a few
temperature sensors around the towers to automatically shut it down in
the case of poor aim. Just because it's not radioactive doesn't mean
it's not dangerous.
On 05/30/2016 12:02 AM, ChemE Stewart wrote:
You guys are ignoring all of the mechanical and structural challenges
of pointing 350,000, 30 foot mirrors at the ground using worm gears
and stepper motors that have just lost power due to a storm and/or
lightning strike. No motor power, no movement. The fuel source (the
sun) keeps moving up and then down towards the west, so the focal
point(s) of all of that incident power is constantly changing.
It is not like a typical boiler where the flame safety system can cut
the source of fuel. It is more like a cross between fukushima and the
towering inferno :)
On Sun, May 29, 2016 at 10:46 PM, <mix...@bigpond.com
<mailto:mix...@bigpond.com>> wrote:
In reply to Stephen A. Lawrence's message of Sat, 28 May 2016
17:18:24 -0400:
Hi,
[snip]
>It ought to be possible to build the things with a fail-safe mode
>wherein loss of power results in the mirrors defocussing.
Shouldn't be
>hard; the /hard/ thing, presumably, is getting them all pointing
at the
>_same_ spot. Making them /not/ do that should be easy.
>
Just turn them all upside down so they point at the ground.
Regards,
Robin van Spaandonk
http://rvanspaa.freehostia.com/project.html
Regards,
Robin van Spaandonk
http://rvanspaa.freehostia.com/project.html
