[Kevin S]

Been reading about these around the web, in principal they seem a good idea but would they really work well in the UK?
here's a link  http://aes.missouri.edu/bradford/education/solar-greenhouse/solar-greenhouse.php  to on I've found with plans.

So has an one got experience of these and more importantly would you recommend building one?

[Gwiz]

I've seen these written about somewhere before, I think it may have been a book from Wisley about greenhouse growing.
The idea is sound, but you'd need a heck of a structure to be able to get in your 26 odd 55 gallon drums? I know there would be questions raised by neighbours/local council around here in the burbs!
Good luck with it though, if you decide to go ahead.

[arugula]

Looks like a great idea, if you have loads of room and no neighbours to object. Dick Strawbridge and Co, in their Its Not Easy Being Green TV programme, made a passive solar heating system for a greenhouse, plans for which you can view through THIS LINK. It is perhaps on a more manageable scale.

[DD.]

Not cheap is it?

Would take you a long while to make up the cost on the fuel savings.

[Paul Plots]

The idea sounds wonderful - nearest I can get to anything lile this (but it probably isn't  :blink:) is to rely on a lean-to-greenhouse that leans on a very solid high concrete block wall.

The wall soaks up the sun's heat (I'd be lucky at this time of year) and adds several degrees to the internal temperature helping to hold over-night temperatures up.

Not the same thing I'm sure but on a very small simple scale it does help keep the early spring seedlings warm once they are hardened off a little.

[Trillium]

A lot of passive solar greenhouses here are lean-to's rather than free standing, as said earlier, to take advantage of brick/stone walls to absorb heat and to place large water drums against to also store heat.

Another good alternative is what we used to call pit greenhouses, where the lower half is dug into the ground with stair access, and the upper glass part just above ground level. It helps a bit more to moderate heat but you'd still need to trap heat somehow.

The key is whether or not your area gets a lot of winter sun to make it worth while. Salvaged materials can greatly reduce building costs but without enough light, it's a futile gesture. It would work for me because even though I get a great deal of snow, the snow reflects a lot of light, which in turn creates/traps some heat.

[Paul Plots]

They have some lovely "pit" greenhouses at West Dean not far from me in Sussex. They often hold a tomato festival there too.

Worth a visit if you are in the area. West Dean Gardens