Thanks for that. I simply chose the vacuum tube as the most 'efficient' collection mechanism per unit area as roof space is potentially limiting, and considering other costs, I hadn't looked at the collectors in any more detail.
What you say about glazed and vacuum in series sounds very interesting. I don't know if you've revisited my page very recently, but I've thought a fair amount about having an in-house thermal store to cover more than a days' energy to ride out cloudy days and to allow the heat-pump to run only when local solar PV is available. The water in that over-size hot-tank should be kept above 60C to kill Legionella, so higher temperatures from the solar thermal collectors (to minimise need for a the heat-pump when it would be rather inefficient) would be good to help achieve that.
Actually, roofspace would seem under greater attack from the solar PV needed to drive the heat-pump according to my sums! I'm running out of fingers and toes... B^>
It's now starting to look to me that to be truly carbon-neutral all year round, even each and every mid-winter day, with solar thermal and PV as the RE sources, is looking more like £200k, which just shows what the grids (electricity and gas) and a stable society (to allow them to exist) do for us!
Our current house probably isn't going to be the one to get the treatment, but when we choose our next one, we'll be looking for something that can support some or all of these mechanisms.
Rgds
Damon
[ Parent ]
