Dear Joe (and everyone else who has written!)
Thanks for your kind note.
I AM still working on this project and I did make some progress last year which I have yet to write about.
I manufactured about a hundred ribs in preparation to replace and double the number of the collectors in my array to a dozen (each is about a sq metre). I shot video to clarify some of the steps in the process. I sourced new components and especially new thin lexan mirror which should be more durable. I refined the sensor housing. I obtained instruments to help me verify temperature and flow to better assess performance. I rejected and then re-thought an approach to UV sterilization of the pool water.
As you can see from earlier write-ups I use these DIY collectors in a high flow, low temperature rise mode to heat lots of pool water by only a small amount. Most people don't use concentrating collectors this way yet they have some advantages over flat plate type collectors, like lower cost, although they have higher complexity.
It could be very useful to heat fluid at a lower flow to a much higher temperature, which you can do with a concentrator. If the water doesn't flow in my system, that is if the pump is off, the water in the collectors will boil in about 20 minutes. I have no doubt that if you paid attention to the fittings, you could safely make steam and lots of it.
My mom died last summer and that put a damper on things.
I will let you know when there is something new to see here.
Many thanks for your interest, I do welcome your correspondence.