The Vdara Hotel & Spa, a glass structure, famously sprung a death ray that would reflkedct the suns rays and was hot enough to singe hair or melt plastic. Apparently, intense heat is created by the curved glass surface of the hotel, which acts as a parabolic dish. The glass bounces the rays from the sun and concentrates the light in 10-by-15-foot hot zone on a portion of the pool deck.
How would you solve this issue? (or avoid it!)
On a more serious note... there are quite a few things they could do. Here are some quick ideas:
there are foils that act as fresnel lenses. these can be used to diverge the solar beam instead of the converging aciton of the glass.
fresnel lenses are found in credit card size flat optical magnifiers, but there is no objection to increase the size.
I have flat reflecting glass on my house. Not an issue
For your curved surfaces, I would add difuser ribs to the windows to reflect the light in diferent directions to reduce the heat intensity.
The first step would be to identify the area affected throughout the pool season. Next I would have structures built with a series of pleasant-looking reflective panels that would block the death ray throughout it's travels without blocking the sun from the pool area, if possible.
I'd say map out the travel of the hot spot over the course of one full year, then build a shallow pond covering that area and about 18 inches beyond it. Plant shrubbery/place potted plants around the perimiter to keep idiots- er, guests from wandering into the deat ray's path and allow everyone to marvel at the new attraction, a water feature that spontaneously boils. And if the pond dosen't get hot enough to boil, congradulations, you've successfully contained the rouge solar energy.
A reasonably simple engineering solution would be to apply a circularly polarized film over the select area that is reflecting down to the pool area. As light passes through the polarized material it twists 90 degrees reflecting back from the already reflective glass out of phase, as it were. This then blocks the reflected light from affecting the pool area. A thin diffuse glass with an IR filter coating on its back side couldn’t hurt as it would protect the polarized film from the elements and further reduce the IR from being reflected. This is not new technology. Virtually every LCD screen uses this technology
1. Set up a solar collecting parasol, either hot water or solar electric. The hot water can be used for the jacuzzi.
2. Set up a Stirling Cycle engine to run a large fan or air conditioner, or the forementioned sculpture
3. Paint the sidewalk with color changing liquid crystals so people can see the hot spot.
Half kidding aside, as for eliminating the problem, that would take some modelling to show the position of the hot spot during different seasons of the year at different times of day. The pattern may indicate when there is and when there is not a "problem". Narrowing down the scope of the problem may help identify solutions. It may only be practical to mitigate, not "solve" the problem... Some of the "avoidance zone" solutions above are quite ingenius.
Similar refractive devices in windows (fish bowls, decorative bottles, oil lamps) have been responsible for igniting fires.
Have the engineer plot the points of convergence from each window. Then decide on an acceptable wide area of convergence that spans perhaps the width of a building. Calculate the degree angle for each window to hit the area so that no more than one or two windows hit the same spot. Call back the window glaziers and have them reset each window to the 2 degrees of angular movement up/down, and left/right to match the engineers chart for each window. This will diffuse the light, will not affect the view that the guest is paying for, and will still use the same window mount for the panes. It shouldn't seriously affect the ability of the window washers to do their routine maintenance either. The convergence calculation will have to run for a 4-year cycle I believe, to cover all the changing angles of sunlight.
Wow, I think that this is the first reply that seriously looks at eliminating the problem at the source instead of looking at ways to keep people from walking into the death ray's target zone or slapping coatings on the windows that would alter the guests' views outside.
It also sounds hugely expensive. I never knew window glazers could work at that level of precision on a building, getting a window lined up to within a couple of degrees; that level of cratmanship isn't likely to come cheap.
I'm sorry, I meant that the 2 degrees of freedom are, #1, left-right, and #2, up/down, not, as it were, to hold the tilt to an accuracy of 2 degrees of arc. To be sure, the amount the glaziers would need to offset the pane of glass will probably be somewhere up to 10-15 degrees towards the worst case, which would be the mid-height of the buiding because all the easy spots of window focus have already been taken (so that not all the windows have to be adjusted). Some windows can be selected to focus where they are, and the others adjusted around that to fill the selected zone. The top of the building requires very little angular offset to cause the beam to fly out of the focus zone altogether, bcause of the greater distance to the target - like trying to focus a binoculars steadily on a distant site. The worst thing about the super-focused light now is that it increases dramatically the chances of cataract development and skin cancer, even more than the alarming heat generated.