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Forum Index : Solar : Solar Trek
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Solar Trek -- Exploring New Ideas -- Going Where No Man Has Gone Before (qeue music) I'm starting a new thread here because I wrote a reply to a thread fillm started and it was starting to be a "hijack" so here's my reply and a reply from RossW I copied and pasted and we'll just go on from there: Crew Hi, me again. Say, I was just brainstorming over a fruit smoothie (sugar rush) and the thought of using Coroflute as a flat-plate solar (water) panel came to mind. I'm the guy who build his turbine blades from 4mm Coroflute, remember? Anyway, I've never tried this, but if the Coroflute (say 4 to 8 mm) were sealed into a slot in the bottom of a horizontal containment vessle and a feed line attached similarly to an intake manifold at the bottom of the panel (cold side), the internal flutes would be great at thermo-siphoning the liquid heating inside and you'd have a dandy collector that would likely not be harmed by freezing weather. As to whether the plastic would "melt" with the heat, well, that remains to be tested, but if it holds up, wouldn't a painted-black sheet of Coroflute supported on a sheet metal base be just the bee's knees? Bee's knees is "Americanese" for dandy. RossW's Reply MacGyver wrote: Crew Anyway, I've never tried this, but if the Coroflute (say 4 to 8 mm) were sealed into a slot in the bottom of a horizontal containment vessle and a feed line attached similarly to an intake manifold at the bottom of the panel (cold side), the internal flutes would be great at thermo-siphoning the liquid heating inside and you'd have a dandy collector that would likely not be harmed by freezing weather. As to whether the plastic would "melt" with the heat, well, that remains to be tested, but if it holds up, wouldn't a painted-black sheet of Coroflute supported on a sheet metal base be just the bee's knees? Bee's knees is "Americanese" for dandy. I've been mulling this over for 18 months and haven't had time to try it yet, but it's a very similar idea. Rather than corflute which (if I'm thinking of the same stuff as you) is translucent white and doesn't actually pass as much heat as one would like, I was thinking of using clear makrolon or lexan in the 8 or 10mm versions. These are made of clear polycarbonate and have 10x10mm or 8x10mm (or very close to) square channels between two clear sheets. I was going to seal top and bottom to standard aluminum U-channel to make the collector top and bottom, and (here's the kicker) - use old black oil for the medium. It won't boil, it should *directly* be heated by the sun. A simple heat-exchanger to extract its heat into water for use. I haven't built one yet to test, but like you - one of these years :) Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
RossW I had thought of merely painting the front surface of the Coroflute black and relying on whatever heat transfer I could get. Plastic is not a good heat conductor, but it is what it is and right now, it's all I've got to work with. I did see somewhere back in the day where someone had an aluminum extrusion, which was on the order of the square-fluted Coroflute. That'd be the stuff to run your oil through! I know water would eventually mess with the bare aluminum, so your idea of running oil is a perfect fit. I've built oil-filled rigs in the past. My first one ran used motor oil, like you're suggesting, but later versions used clean cooking oil. If you do wind up using oil, be extremely careful with it. Hot oil sticks to you and you can't wash it off fast enough before it delivers a serious burn. That's "serious" with an "S" as in Sizzle! Please be extremely careful. My oil-filled rig got up to over 400* F as I was using concentrated sunlight on it (4 flat-plate mirrors). If anyone knows a source for an internally-fluted aluminum extrusion, I'm all ears! . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
A character I know has a solar hot water collecting manifold made using a series of 1m long 8mm black poly tube(as used in irrigation) connected into cold feeder poly pipe at bottom and hot feeder poly pipe at top using those cheap drill in poly irrigation nipples to couple the 8mm to 25mm headers. No glass over the top just laying on his roof, seems to work ok. The corflute or makrolon approach using oil as the heat "carrier" has got my scrambled brain cells working. Once I`ve replaced my current gas fired hot water system I will have a totally non fossil fueled household so will be watching this thread with much interest before acting. We come from the land downunder. Vic |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
norcold I haven't completely forgotton about this thread, but I did spend the entire day setting up my hydroponic garden. As soon as I can sweep some of these other 'household' projects under the rug, I'll set up a small collector using Coroflute -- Solahart style with the receiver at the top and post the results here. Really! . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Your right Mac, will follow this post and chip in when I have something. I like the black poly manifold just are not real sure of the claims the fellow who made it has made. No doubt the water gets hot in poly but you would need a massive surface area exposed to the water at the low water flow required. Guess I`ll have to bite the bullet and get another project started. One more will not hurt I guess. We come from the land downunder. Vic |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
norcold Seems to me, knowing the internal friction of something like Clroflute is so high, setting up a flat-plate solar panel to thero-siphon to an elevated tank, like the way Solahart does it, makes the most sense. I'm worried about the plastic sheet holding any kind of pressure, expecially when things heat up. I guess a fellow could just leave the system open or put a burp valve on it, but even then, it would seem better if the collector were made of metal. I once had the brainy idea to lay a piece of #4 copper wire in a surpentine fashion between two copper plates and then solder the whole thing by dipping it into a pool of heated solder, but I never took the time to actually try that. I suppose that'd be a good way to make several smaller strips, then join them together with top and bottom manifolds, eh? It's mind boggling how many ways this could be accomplished. Like I said, when I have more time to devote to this, I will. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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readyakira Senior Member  Joined: 17/07/2008 Location: United StatesPosts: 114 |
I don't think coroflute would have the longevity you seek. Not to mention the higher pressures that home water uses comparede to say a swimming pool. I pool runs I believe 12-20psi where in a house you are usually 40+ I know they use a coroflute type panel here in the states, but they only use those on pools, and panel life is no where near that of a copper system. I have a friend that used actual pool panels but it only lasted a short time over a year before it started to leak. BTW I started a post on the hot water collector project I am starting (well have been slowly starting for 6months!). Don't you think Free/Renewable energy should be mandatory in new buildings? |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
readyakira I tend to believe what you're saying about the Coroflute not withstanding any pressure. Like I said, somewhere back in the day, I saw an aluminum extrusion that was done on the order of Coroflute and that would definitely hold pressure. If oil were run instead of water, there'd also be no problems with corrosion. When this project finally gets down to my actually doing something, I think I'll do something along the lines of building a flat-plate copper panel with a #4 solid copper wire soldered inside forming a series of convolutions or maybe even a serpentine pathway for the trickle of water that is to pass through the thing. I figure I an solder things in copper using a few tricks I've learned in 40+ years of plumbing. Building one from aluminum may prove to be a bit more daunting. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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