Reader questions and answers

Hello Carlos and thank you for your interest in my book. My answers are below:

On 12/14/2011 08:06 PM, carlos e wrote:

Hello Mr George,how you doing?
I see that you have a great job on this things,congratulations.

Thank you.

I brougth from you the plans to make my own unit...but I need to get some awnsers first.
Did you have some problem with acrilyc durabitity?

At first yes but it was a problem of my own causing. I let the concentrated light that was not properly focused at the collector tube hit the back of the sheet in front and the sheets were deformed by back heating. This damage occurred when the unit was OFF and not following the sun under control of the sensor. This was solved by painting the backs of the acrylic sheets white and when not using the array, parking it horizontally. The current acrylic is on the third year of use here. It needs a good cleaning in the spring, but it is fine. You can read more about that here:
http://georgesworkshop.blogspot.com/2009/07/mirror-distortion-is-due-to-back.html

Did you tested some others interesting materials?

I did. In the book on page 30-33 I talk about MIRO IV polished aluminum, Galvanized steel (no joke), aluminum roof flashing, reflective film and acrylic mirror. I did not try polished stainless steel since I could not find it locally but others like this material. I would like to review the situation again since many different kind of materials can be used.

I am thinking about making some examples and sell it to some people but you know,I am a serious person I dont want to sell a bunch of problems to my friends..in case that they need to change the reflector in a short time!

I suggest you make one for yourself first to get experience and to adjust for local materials and situation. You should do your own life testing. Maybe your acrylic is different from mine but we don't know that until you use it for a while.

How long is your device working?

I started six years ago. The current "production" array which heats the swimming pool is essentially the same for three years. I am now replacing some worn parts and poor manufacturing (my own fault).

You did not refer in your plans,the size of your pool,how much litters or gallons do you heat with your unit?
Can you hit wich temperature increase in one day?

The pool size is about 50,000 gal, I talk about that here:
http://georgesworkshop.blogspot.com/2010/03/what-size-of-pool-heater-do-i-need.html

what about trying 2 axis track in your model..it seems to be easy to do,do you think it will get some important increase of power?

Please tell me how to do it easily. The seasonable adjustment seems like a small benefit. The big operators in the desert do not do this. But reader Andrew Gray wants to try to do this also:
http://georgesworkshop.blogspot.com/2011/09/reader-projects.html

And about the ribs,do you think for example 10mm acrilyc it will be good to use instead of wood?
probably it will last more and no need to repair

I think it will depend on your conditions. Here there is winter cold (not good for most plastics) and wind but we do not get hurricanes, nor really heavy hail like they do in Texas. The wood highway sign material (MDO) is turning out to be very durable here but the edges must be sealed. The baltic plywood is my favorite, to be cut with a water-jet. But please try the acrylic. Check that it is UV stable. Use a lightweight material, like the wood laminate or plastic or you will be re-balancing the reflectors.

thank you so much.

ps. about mylar film can you share your experience with me too?

I did not use it. I thought it would be difficult to apply smoothly in small quantities and I was concerned about the durability. Others have used it with success. The manufacturer of Reflectech film recommends a purpose built "application machine" but I can't afford one of those nor could most of us, I thought.

Sorry if I am making a lot of questions but you seems to be a helpfull person and I really need your help!
My inglish is not very good,sorry for that...

Your English is GREAT! Thank you for your questions.


George