Thanks

Lachlan M of Australia wrote:

I recently bought your down-loadable plans on how to make a solar parabolic trough.

Thank you so much for your excellent work.

What I find most inspiring is that you have made your many years of research available to anyone with a searching mind who can afford $25. As such you have made available to a huge number of people the technology to collect a large amount of the sun's radiation.

You could have opened an expensive Solar Trough manufacturing business but you have gifted the world with your educative ideas instead. Thank you indeed. 

Wow! THANK YOU for the kind words Lachlan!
George

Solar test Jig

I have been working on a test jig to allow me to mount and compare different solar thermal collectors of a standard 48x24" size in a tracking configuration.

I finally rolled it out of the garage today. The motor drive and the collectors are not yet mounted but the frame is pretty much finished.

This jig will allow me to compare two different collectors. The jig will have two independent insulated water circulation systems represented in the picture by the two coolers which will hold two same volume batches of water and two immersion pumps. By measuring and comparing the outlet temperatures, I will be able to quantify which collector is better at converting sunlight into heated water.

I will provide more details as the project progresses.

You can click on any of the pictures on my blog to see enlarged versions. The blue in the first picture is a tarp over the woodpile in the background, nothing to do with the solar test jig.

Thank you for your interest in my work.

Index - Comparing concentrator to flat plate solar collector

Compare to flat plate collector?

Peter from Queensland wrote:

I have an engineering background & must tell you that your website is perhaps the most professional in content & presentation, well done.

My interest is in a domestic solar water heating array for general purpose home use.

We are Queensland, Australia (Brisbane are) based, & so in ideal conditions for solar deployment much of the time.

I note the success of your array used as a swimming pool heater & wonder if you can now comment about the relative merits of this or similar designs compared to the more conventional DIY copper tube/aluminium fin collectors and about roof mounting.

Any comment, advice, or guidance you care to make would be greatly appreciated.

Thanks, Peter

Thank you for your note and for your kind comments.

I am the first to admit that mine is rather an unconventional design for a home built project. Although I feel that I have achieved good success in my intended application, there is no question that it is a more complex project and therefore not for everyone. Nevertheless hundreds of my plan book have been sold and my heater works well for me and it is a source of personal pride.

Many pursue the flat plate fin/tube design and some are quite nicely done. Probably the best place to look for these is at www.builditsolar.com. Gary has done an excellent job fostering the community of solar builders.

I have had many good discussions with Gary and some of his readers and they have made great suggestions. Probably the bottom line is that for heating water to the relatively lower temperatures of DHW or pool heating, a moving parabola is overkill and too complex for most people. I have several other applications in mind for a parabolic heater where the advantages will be better utilized but I do not for a minute regret the effort that I put into my project. Gary features my design on his page for concentrating heaters.

My advice in the book is to not place my collectors on a roof. Two reasons for this: as they are home built, easy access is desirable since you may need to work on them and the second reason is that wind load may be more of a problem in a more exposed location, like on a roof. A flat plate system is definitely better if mounting must be on a roof.

Whatever you decide you need, I wish you luck with your project. My book is inexpensive and dreadfully thorough and you might consider it as a bit of background reading for your research?

Thank you,

George Plhak

Index - Comparing concentrator to flat plate solar collector