I was thinking about either making a small (3'x5') solar air or water heater and running it under a raised bed. water/glycol heater may be too much heat, and an air heater would be safer. Got to finish the solar air heater for the house first. Does the cleardome fabric work well in the house?
The Cleardome solar thermal drapes work extremely well in the house. We have a lounge with many South and West facing windows. Even when the temps outside are down to -28 we can still harvest solar heat with them. If you stand in front of one of the drapes you feel the warmth radiating off them. Even better are the stick-on panels that they do. What I'd really like though, is their solar heaters. Very reasonably priced, but out of our budget at the moment.
We are going to try to do some experiments with solar box heaters now. I'd like to see if we can heat the hen-house a bit and see whether we can rig one up to add some heat to our (frozen) pond. Even a small bit of water would make our ducks happier!
Then there's the possibilities to warm the polytunnel a bit to get our growing season started a bit earlier. Lots of possibilities, if only we had the know-how!