Vertical Vacuum tube hot water heater

Jeepman401 · Mar 29, 2015

http://www.siliconsolar.com/30-vacuum-direct-flow-solar-collector-p-18116.html
Has anyone seen these or used them on a small scale for floor heating in concrete? This type can be vertically mounted. Different than the others that are mounted at an angle. Thinking of using them in my garage, highly insulated walls, ceiling... 24x34 with in floor heating. Still needs finished, but the walls are 10" thick and will get dense packed, cement floor in enclosed with 2" pink foam, no part of the concrete touches the ground.
I have a lp boiler but was thinking maybe using the refund from my solar install(keeping same deduction so I'll get a refund next year) to purchase a couple of these.
They would be mounted vertically under the overhang so there would be no snow collecting on them, exposed to the South...
Just getting ideas at this point. Would be happy just to keep it 50-60F inside during the winter and not have to pay for heat. But at $2000+ plumbing I would be hesitant....

jebatty · Mar 30, 2015

There is nothing new about this nor about vertical mounting. As best as I know all evacuated tube units need to have a positive slope to function, vertical just being a maximum positive slope. Look at the specs: 5923 btuh for a 30 tube unit. That will be maximum output, full sun, although based on experience evacuated tubes can do well under cloudy sky conditions but not shade, and they also do well in freezing weather. If your building heat loss is 24,000 btuh, you would need 4 - 30 tube units which would work to heat the building during the sun, but what about the long winter nights?

Vertical mounting, yes, but how do you move the heated water through the pex in the concrete? Circulator(s) and all the other hardware and temperature control for any other hot water hydronic system, plus hot water storage.

Pitfalls: they may not be freeze immune, and damage can occur if subjected to excessive stagnation periods.

For more info on an operating evacuated tube system:https://www.hearth.com/talk/threads/solar-evacuated-tube-domestic-hot-water-system.128733/

Jeepman401 · Mar 30, 2015

jebatty said:
There is nothing new about this nor about vertical mounting. As best as I know all evacuated tube units need to have a positive slope to function, vertical just being a maximum positive slope. Look at the specs: 5923 btuh for a 30 tube unit. That will be maximum output, full sun, although based on experience evacuated tubes can do well under cloudy sky conditions but not shade, and they also do well in freezing weather. If your building heat loss is 24,000 btuh, you would need 4 - 30 tube units which would work to heat the building during the sun, but what about the long winter nights?

Vertical mounting, yes, but how do you move the heated water through the pex in the concrete? Circulator(s) and all the other hardware and temperature control for any other hot water hydronic system, plus hot water storage.

Pitfalls: they may not be freeze immune, and damage can occur if subjected to excessive stagnation periods.

For more info on an operating evacuated tube system:https://www.hearth.com/talk/threads/solar-evacuated-tube-domestic-hot-water-system.128733/

Yeh, the $ part is hard to work out on this one. I wish the price would drop on these like they have on PVs. Thanks for the reply.

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Vertical Vacuum tube hot water heater

Jeepman401

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jebatty

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