- I left some comments for Rob over at iwilltry.org. This dude is obviously sharp as a tack and is doing some some great things. He wrote an article over at instructables on how to build a solar thermal panel with plastic, but ran into the problem of overheating. This is exactly what I was trying to solve with the particle panel idea.
- I joined the forum over at solarpaneltalk and started a thread. These guys are great and very helpful.
- I left some comments over at The Sietch Blog. Scroll down to comment 194 to see the discussion. Turns out there is an expert who calls himself CaptBilly behind the blog, who is very outspoken and full of great info. He is pretty concerned about the panel not having low enough emissivity. I understand what he is saying, and he has a good point. Many thanks CaptBilly for the lesson. I also think I am on the right track. Nothing he has said so far is making too nervous. (but perhaps it due to ignorance?) Its exactly these sort of details I need to know if I am going to succeed at this. My main goal is to drastically increase the Watts/Dollar of solar thermal energy. If the efficiency of the panel drops a little over current systems but the cost goes down by 80%, the net gain is still very big. Actually, I am going to be blunt. If the cost of solar thermal panels were reduced by 80% it would cause floodgate to open. I, by the standard of my peers, make a lot of money. And even I could barely afford to use solar thermal to heat my house (or geothermal...I was quoted 40k). To be honest, when I went to my local distributor and they quoted me $3,000 for one 4'X8' solar thermal panel it pissed me off. This is not a technology that should be expensive, and the fact that it is not dirt cheap tells me there is a gotcha somewhere (and you know what I think that gotcha is...right?).
- I started a thread over at Tree Hugger. Maybe its just too mainstream, because as of now 12 people have viewed it and no comments. I have a feeling its going to really take work to make people see the advantages of cheap solar thermal.
- I created an instructable. This site is really great. Many great great people. What a fantastic way to use the internet!
Well, I am now packing for a business trip. (I consult for a couple of government programs that are trying to build chips like brains, partly inspired by my work) I will be gone all week. I'll try to check in and answer comments and keep up with the activity if I can.
So after my discussion with CaptBilly, I thought I would look around a bit. He doesnt understand how this concept could result in a less expensive panel. Thats sort of unnerving, particularly since he seems to be so knolwedgble. I found references to "all polymer" absorption plates in the wikipedea article on solar thermal panels. I googled that and found this paper. I hesitate to order the article, as the abstract seems to say it all:
"Venting and evaporative cooling are modeled as possible techniques for protecting polymer absorbers in single-glazed, flat-plate solar collectors from exceeding the material temperature limit during dry stagnation. Four venting options are considered: (I) venting above the absorber plate, (II) venting below, (III) dual venting, and (IV) venting with evaporative cooling. Results indicate that in hot, sunny conditions, venting may not provide adequate cooling to lower the absorber temperature to the relative thermal index of the polymeric materials currently in use or under consideration for this application. Venting combined with evaporalive cooling from a wetted pad directly beneath the absorber plate is identified as a potential method of overheat protection in hot, dry climates."
So it appears other are struggling with this problem. Could the particle panels be the solution? Stay tuned...
Blue Skies,
Alex
Here's your plastic collector.
ReplyDeleteIt's freeze tolerant and vents itself if it gets too hot.
This Israeli company seems to be very smart with plastics.
http://www.magen-ecoenergy.com/htmls/Polymeric-Solar-Collector.aspx?c0=13289&bsp=13283
By now you must be aware of Gary Reysa and builditsolar.
ReplyDeleteHe describes a very robust collector and system that is mostly plastic with aluminum fins. Since Al is earth's most common metal, its cost should remain low.