Win a copy of 5 Acres & a Dream this week in the Homestead forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources the cider press projects digital market private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • Anne Miller
  • Pearl Sutton
  • r ranson
  • Mike Haasl
  • James Freyr
  • paul wheaton
  • Joylynn Hardesty
  • Burra Maluca
garden masters:
  • Steve Thorn
  • Greg Martin
  • Kate Downham
  • Jay Angler
  • thomas rubino

Passive solar water heating DWC rafts

Posts: 21
Location: Colorado Springs, CO
forest garden fish fiber arts
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Background: I'm in the final steps of setting up an aquaponics greenhouse after running a smallish indoor system for several years. While our indoor system is pretty conventional, for the greenhouse I wanted to marry aquaponics and "Summer Tubbing"-style fish breeding to create something more in line with what I've been learning about permaculture. (I plan to breed threatened species of nano fish rather than food species, both because it's something I really enjoy doing and because their lower bioload makes low-tech systems easier.) I'm still in the early stages of cycling the tanks (6 200gal IBC sections) and adding some plants, and I'm currently using electric heaters while I work on better solutions. I'm at 6500ft altitude and have no shade, so I feel pretty sure I won't need to run the electric heaters for long.

My first experiment was to take a piece of scrap foam, cut a hole in it for a 3" net cup of hydroton, float it in one of the tubs, and add some kale seeds. It's been a week so far, and they seem to be sprouting pretty well. I figured I'd keep an eye on them, thinning when necessary, with a goal of seeing if I can grow a plant all the way to maturity without capsizing or root rot.

The improvement I thought of yesterday but haven't had the chance to try yet is to take some dark-colored soda cans, cut them up so that I have a rectangle of thin aluminum, and then attach them to the DWC foam with the dark side facing up and one end going a few inches into the water. (Ideally I'd go as far down into the water as I could to promote water circulation, but I haven't figured out how to do that with available materials so far.) My hope is that during the day, the dark aluminum will collect heat and shuttle it into the water, and at night, the aluminum will gently radiate heat from the water to help keep the plants warm.

Has anyone tried something similar? Am I overestimating the heat conductivity of aluminum cans and setting myself up to cook my plants? Any suggestions on foam sources or substitutes that don't put extra styrofoam into the world?

A wop bop a lu bop a womp bam boom! Tiny ad:
Permaculture Technology Jamboree: June 29th-July 10th, 2020, Wheaton Labs
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!