Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,059
The products I've seen have evacuated tubes clamped in a manifold. They will work in freezing, and stagnate above boiling.I think 50 X more efficient is said for effect. I was just trying to find out how efficient these evacuated tubes are. I’m sure that aside from the 20% efficiency of the solar panels, there’s a pretty huge loss of taking this electricity and converting it to heat, but now enough to make the 50 X efficiency that’s claimned. Anyway, that google research will come later.
I’m also wondering if these Tubes are used for the Canadian winters, I understand the vacuum tube not freezing, but how about the copper pipes between the tubes? Some pretty cold nights up there. The problem was overcome somehow because people are using these, I just don’t know how. FOr me, that’s google research for later.
You either need to run an antifreeze mixture (e.g. non-toxic propylene glycol) and heat exchanger, or push warm water through the pipes when weather gets down to freezing.
Alternatives could include an air relief/vacuum breaker for a drain-back system. I've also thought about putting an air-filled silicone tube through the pipe to allow water to expand as it freezes.
You'll find systems on eBay and elsewhere, around $1000. Some have a storage tank at the top end, so no pipes between collector and storage.
They do have some finite lifespan. Not entirely clear that exceeds a decade.
Because I'm on-grid with net metering, I've just over-paneled PV and used resistance heating.
For OP, water tank above evacuated tubes and PV/battery circulator pump sending water through tubes under yurt floor might work pretty well.
Blowing air over a radiator attached as thermo siphon to water tank could do it too; then all plumbing is in insulated volume.
But the warm floor is nice. Probably want warm air to go under it if not water. I want something like that in my house.