I’ve advertised this on here before but got no takers, now I really need the space so it’s got to go!
I have for sale a Solar Thermal water heating solar panel. It’s a DIY copy of the the Solar Twin panel (see https://www.solartwin.com ).
An aluminium frame, with an aluminium back panel with a serpentine pattern of silicone tubing attached to it, silicone tubing is used as it’s freeze tolerant. In sub zero it just freezes solid (expanding a little), when it warms it thaws out and carries on, unlike copper that splits. This means it can be used as a direct system to heat the water in the tank. The silicone is medical grade so the water will be fine. The back of the collector, which is painted high temperature matt black, is insulated with kingspan type foam board.
The panel cost £250+ to build due to all the aluminium/foam/silicone involved, as well as long time to construct. I’ve got brackets and bolts to mount it the roof, which are included. It was used for over a year and worked very well, it was only replaced due to lack of roof space when I had solar PV installed.
You will need a small pump (which you can pick up on ebay for less that £20) and some form of controller to run the pump when the panel temperature is higher than the tank temperature. I used a DIY Arduino setup, I can let you have the plans and code if you’re interested.
I’m in Milton Keynes in want a look at the panel. First sensible offer secures it!