The plastic sheet process is different from the one in the article. In the case of the plastic sheet, you are baking the water out of the ground, not extracting it from ambient air. It seldom works well in practice, because you get a little condensation under the sheet, but it's not enough to run in rivulets into the jar, and when you DO get a few drops in the jar, the same process that is baking the water out of the dirt evaporates it from the jar. You end up shaking the plastic, lifting it up and licking it.... Works better in theory than in practice.
But imagine that, instead of a special water bottle, you have a poncho-sized sheet of coated plastic in the shape of a windsock with a coiled wire ring at the opening and a pouch at the end. If this could work like the beetle's wings and take water out of the ambient air, that would be interesting.
I spent some time learning from a respected survival expert who claimed the 'solar still' was not an efficient use of one's energy. I tried it out a couple of times anyway and proved to myself that he was right.
What did work fairly well was a transpiration bag [1]. It took a few bags to get a meaningful supply of water and one needs to be careful about the foliage used.
Comments
The plastic sheet process is different from the one in the article. In the case of the plastic sheet, you are baking the water out of the ground, not extracting it from ambient air. It seldom works well in practice, because you get a little condensation under the sheet, but it's not enough to run in rivulets into the jar, and when you DO get a few drops in the jar, the same process that is baking the water out of the dirt evaporates it from the jar. You end up shaking the plastic, lifting it up and licking it.... Works better in theory than in practice.
But imagine that, instead of a special water bottle, you have a poncho-sized sheet of coated plastic in the shape of a windsock with a coiled wire ring at the opening and a pouch at the end. If this could work like the beetle's wings and take water out of the ambient air, that would be interesting.
I spent some time learning from a respected survival expert who claimed the 'solar still' was not an efficient use of one's energy. I tried it out a couple of times anyway and proved to myself that he was right.
What did work fairly well was a transpiration bag [1]. It took a few bags to get a meaningful supply of water and one needs to be careful about the foliage used.
[1] http://www.youtube.com/watch?v=q2EBiA0Csts