Scott -- a quick preview of the 100 sqft collector.
Idea is to combine DHW and space heating in a simple system.
Would like to have done more collector area, but no more room on the south wall.
Still using the "Solar Shed" with 240 sqft at well.
Absorber b4 painting. Used lots of drainback slope.
Return from top left of collector goes down behind the absorber to a level it can go into crawl space.
The new pump and U-tube -- a Grundfos 15-58 3 speed -- 60 watts on low speed achieves nearly 5 gpm through the collector.
Tank is located in crawl space below and behind the collector wall.
A 3 inch wide strip of 0.018 alum goes under the copper tube first.
The fins with the pre-formed groove (from Tom in this case) get snapped over the tube, and then clamped in place tight
over the copper tube (in this case with clamps borrowed from Tom).
Short self tapping screws are then used to fix the fin to the flat, 3 inch wide strip that is under the copper tube.
This keeps the fin clamped tightly over the copper tube. As the very very thin layer of silicone that is placed in the fin groove sets, the fin to tube joint becomes very bombproof.
The 3 inch wide strip adds to the thermal conductivity of the part of the fin that is closest to the tube where heat flow is greatest.
Nearly finished absorber plate before painting black.
The manifolds are 3/4 inch and riser half inch. Reducing T's used to connect them -- something like 150 solder joints, but nice easy ones -- no leaks :)
PEX Supply has a great price on the usually expensive reducing T's.