This device is a rather unique way of approaching a difficult problem.  In virtually any mirror system, the focus is fixed at a given distance and the density of the sunlight is also fixed.  I wondered if a system could be made from a flexible material that would provide a means of changing the focus easily, allowing the effective temperature to be controlled- as well as the "throw distance".

   The original challenge was to demonstrate the power of sunlight for a sponsored museum exhibit on energy.  The science is simple enough- create a device that can throw a beam of concentrated sunlight at a given point on demand.  This would allow sunlight to be aimed at a boiler or heat storage device.  In the case of the exhibit, it would be used to ignite a piece of lumber (a scrap of 2x4) some distance from an audience.

   The bottom line is that using commonly available satellite dish surplus and a "space blanket" made of silver Mylar plastic (and available in any sporting goods store) you can make a powerful energy collector that can operate a boiler and run a small generator.  It could also be used to raise water or any other working fluid to a temperature that is otherwise impossible with passive solar collectors.

To start the project, I needed a stand or mount to put the collector on.  I had a scrap "Muzak" satellite dish measuring 1.4 meters in diameter.  The same surplus source had the metal stands (made of galvanized steel) used to mount the dish.    The first step was to clean the dish and stand hardware.
This is one of the many identical sections of galvanized frame.  Having this on hand saved me a lot of metal cutting and assembly.  It also meant that the frame would be heavy enough to keep the finished unit from being turned over in high winds, which is often a problem with dish mounts.    Galvanized frames also have the advantage of not rusting.
I used two of the frames bolted together at right angles as the base.  This gave a very stable square base that could be bolted to a roof or other surface if needed.

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