Ol"Bab--
What kind of engineer were you?
Older Bob?
----- Original Message -----
From: David L Babcock
To: vortex-l@eskimo.com
Sent: Thursday, April 10, 2014 1:55 PM
Subject: Re: [Vo]:Problem with glare at Ivanpah CSP plant
It is a little more complex. There is a distance from the (presumed flat)
mirror such that the angular extent of the mirror is about the same as that of
the sun (1/2 deg). From there out the intercepted flux decreases, by the square
of the distance.
From the birds view, at that distance it sees the whole sun fill the mirror.
Any farther out the image is bigger than the mirror -only part of the sun is
supplying heat.
If the mirrors are curved, then each mirror will have a hot focal point, but
not super hot: again it is limited by the angular extent of the sun and the
mirror. A ideal mirror will project an image of the sun on the boiler (or bird,
if at focus), and the intensity is that of sunlight multiplied by the square of
the ratio of the two angular extents. Maybe 10 or 20 to 1? WAG here.
As Bob points out, the "nimbus" effect strongly suggests that the designers
were aware of a possible problem and made sure mirrors in standby don't all
point at a single point, or even parallel.
Ol' Bab, who was an engineer.
On 4/10/2014 11:06 AM, Bob Cook wrote:
The mirrors would not be focused at one spot when idle. Also it is a good
idea to reduce global warming by directing the light back into space instead
into the ground.
----- Original Message -----
From: Jed Rothwell
To: vortex-l@eskimo.com
Sent: Thursday, April 10, 2014 7:59 AM
Subject: Re: [Vo]:Problem with glare at Ivanpah CSP plant
ChemE Stewart <cheme...@gmail.com> wrote:
Efficiency/85% heat transfer efficiency @ solar boiler/90% mirror
efficiency = 1700 megawatts airborne flux, THAT IS A GOOD BIRD ZAPPER
Close to the tower it would be. When a bird flies a few meters away from
the surface of one mirror, it is no different than flying in full sunlight or
in sunlight reflected from glass or water.
I do not know at what distance from the tower the beams of light join
together to be brighter and hotter than ordinary sunlight.
I expect birds would not approach the tower because it is so bright.
Millions of birds are killed by smoke from coal plants, and steam from
coal, gas and nuke plants.
- Jed
