Ken wrote: > Hi all, > > Sorry for the long subject line but, I thought it may aid in archive > searches... Is there a home remedy to creating a double wall heat exchange? > I have contemplated buying two sizes of copper tubing, inserting the smaller > inside the larger and bending the two simultaneously. I could see how the > inner tubing might kink or flatten out but, I think that would be unlikely > unless I tried to bend too tight of a radius. Is there a better home-builder > solution? Perhaps there is an affordable storage tank commercially available > that makes building a backyard heat exchange mute anyway.? I'm going to need > to come up with a storage tank anyway. I understand the theoretical > pros/cons to internal and external heat exchanges but, what are the > real-world practical differences? >
Disclaimer - I have not tried this myself. I have read (somewhere) that if you start with straight tubing, then pack sand between the two tubes before making your bends, this will avoid/ reduce kinking in the inner tube. Of course, the trick is probably getting all the sand out again before plumbing this new arrangement into the lines. If I end up going this route (double-wall) some day in the future, I think I will put two coils into an exchange tank instead. One coil provides the heat input from the solar collectors, the other coil provides the heat input to the conventional hot water tank. The tank will have a sealable lid, and a lot of insulation. Both coils will be immersed in water in the tank. This way, the lid can be removed for inspections, and the coils can be removed fairly easily for repairs. To date, my solar water pre-heaters are in-line, so no heat exhangers required. Darryl McMahon -- Darryl McMahon http://www.econogics.com/ It's your planet. If you won't look after it, who will? _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
