Greg Martin wrote:
Trace Oswald wrote:I've been mulling this over for a couple days, and the more I think about it, the less I am convinced that the pipe will do anything, or is needed.
Trace, the idea, as I understand it, is that the light entering the greenhouse will heat the air in the upper portion of the greenhouse, but the air in the blackened pipe will heat much more than that and will rise into the upper portion of the greenhouse where it will get diluted back to the same temp it would have achieved if the pipe hadn't been there. But the rising hot air in the pipe will pull air up from the bottom of the 20' wells. This will, in turn, pull in air from the 5' air space in the walkway zone, which will, in turn pull down air from the greenhouse. So the pipe will passively turn the air over in the greenhouse. The big question is how efficiently. It would be very interesting to add some sort of air flow meter on the pipe or else somewhere in the flow path, though the end result can also be measured by with pipe/without pipe temperature measurement differences. They could also build multiple greenhouses :)
I had earlier suggested that the pipe end in a trombe wall, so that that thermal mass could extend this effect to both day and night. Having said that, it would also reduce the maximum temperature of the pipe, which would be expected to reduce the air flow rate during the day. Lots of good iterations that can be made to test what works best once they have this greenhouse up!
If they put more 20' wells in up front they can always cap some of them off to see what the return on investment is for what number of pipes, though that might not be an attractive proposition work wise up front....but it's all an investment in learning. Maybe that could be a stretch goal if they reach a certain level of fund raising?
lesley verbrugge wrote:Another question. We dont have a source of logs on our property but we do have loads of granite and sedimentary rocks plus we could buy cinder blocks. Is there any engineering reason why the berm retaining wall couldn't be constructed with these alternatives? Or for that matter earthbags?
lesley verbrugge wrote:Does anyone have any thoughts about combining a root cellar into the design. Somehow. Space is at a premium for us, and we'd like to combine the two if it's possible. Any of those clever engineering types out there with thoughts on this?
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