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Old 02-15-20, 03:08 PM   #1
Apprentice EcoRenovator
Join Date: Feb 2011
Location: Driftless Region, North America, Earth, Solar System, Orion Arm, Milky Way Galaxy,Virgo Supercluster
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Default menaus2's 240sqft Hydronic Thermal collector

Hi All! It's been a while since I've documented a major project on the forum, so I'll be starting from the planning process going forward.

Last year I installed a 36sqft drainback collector with a 100gal. storage tank on our house. I havn't gotten around to posting the details yet, but hopefully they'll be forthcoming. Suffice to say it works great (roughly 5,000 btu/hr), except our hot water usage keeps it in the 60-90F range. So, it's time to expand big time!

I have a woodshed about 100' away from the house with roughly 720 sqft of wall available, my propane furnace also has a plenum water-air heat exchanger from the wood boiler we removed available as well. So I would like a system that can keep the solar tank above 120 often enough to kill bacteria problems and also use the furnace for space heating when there is excess heat being produced. The collector design should be freeze-proof and have the option to be expanded in the future in a modular way.

I was inspired by Scott Davis' 194sqft pex collector and will also use a gycol loop with copper coils in the tank. I am looking to improve upon the design by using a manifold in the collector with 3 pex-al-pex runs to get better flow, I also plan to use twinwall polycarbonate sheets to get higher collector temps for better heat exchange.

I still have a lot of details to work out that are beyond my experience: relays & pumps and integrating that with the furnace. As well as sizing the collector copper coil heat exchangers in the tank.

I've attached a mock-up of the collector and a possible expansion of it in the future. Also a materials list and cost estimation.

Attached Images
Attached Images
File Type: pdf Solar Build.pdf (38.4 KB, 456 views)

Last edited by Daox; 03-11-20 at 12:39 PM..
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