While looking around the web for construction tips for serpentine solar collectors (flat panel type where the pipe takes an s-route across the collector), I discovered this website with photos from Slovenia.

In Slovenia, they have this quaint little concept called ‘communities’. These ‘communities’ get together and accomplish things that an individual with a credit card might struggle with</sarcasm>

The Slovenian economy ministry and civil engineering institute (ZRMK) appear to offer tools and expertise to enable community construction of flat-panel solar water heaters. The project supplies a pre-formed pipe bending table and an asbestos(!)-topped brazing table. There is also a contraption for holding formed pipes against the collector plates for brazing/welding.

The copper pipe, supplied in rolls, is bent around the track to give it it’s serpentine shape. Brazing paste (a meltable alloy) is then applied to one side of the pipe. The pipe is layed onto the copper collector sheets and held down with the spring-loaded contraption atop the asbestos table. It appears that butane torches are then used to melt the flux/paste and braze the pipe to the copper panels. The panels are then very carefully washed and it appears that another layer of copper (foil?) is attached to the other side to form a plate-copper-foil sandwich.

It’s less clear as to what happens next but it looks like the collectors are given a matt-black coating to finalise the construction. It then seems that rather than add the panels into a individual units, the Slovenians instead set about stripping a large area of tiles from their roof. They build a box into this tile-less section which is then used to directly hold the solar water panels and the glazing is mounted straight over the box (all this is my deduction from the photographs - it may be wrong)