It is really necessary to read most of what is out there wrt mirrors and 
sun power (himemade):

http://www.redrok.com/electron.htm#led3x

sun trackers, parabolic and not, with water boiler, stirling in focal 
point and all that. No turbocharger though ;-)

The 'high temperature' assembly for the hot air exchanger of a 
turbocharger sun-fired device should be possible to assemble by brazing 
if the device will not become hotter than 700 degrees C (at least not at 
the welds). It only needs to keep 2 to 3 bars of pressure, less than in 
a car tyre. I am fairly sure it can be done.

Peter
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