
Originally Posted by
WetRivrRat
hmm... Interesting...
I'm actually shooting for the complete opposite of this theory - I've fiddled with the HHSS enough now to notice that it's built in such a manor that it actually becomes load bearing under my weight (210#) in my ExUL. So, I've actually had to take the template shown above apart and add several inches of fabric to address this issue.
It would seem to me that the ideal in this scenario would to be to actually have an air void, as the presence of the non-breathable fabric would create a vapor barrier. Also, giving it an air void would allow the condensation to occur on the inner layer of the outer barrier. Furthermore, it seems to me that having the air void would help to insulate any sort of UQ that is in place.
Maybe this is ignorance, and it should actually be tightly fitted, but it just seems too 'right' to have a void. Mainly if for just the simple factor that nearly all insulation is rated based on it's ability to maintain resistance to heat transfer. While in general, 'air' isn't the greatest insulator, at least when trapped between two layers of a container it would absorb certain amounts of heat radiated off of a person and with one layer being non-porous it would seem to make sense that this would resist the loss of the radiant heat, thus minimizing the convective heat loss at a point of lapse that would equal the point of increase of ambient temp in the air void due to both convective/radiant heat loss. Thus, an inherit R-Value due to the trapped air void.
Again, this is totally just my understanding, and I'd like those more intelligent in these matters to chime in and help us all out.
edit...
I guess where I'm going with that is this: For some reason or another I recollect that 'air' has an R-Value of '5' per inch of thickness. That being the case, the HHSS UC with my weight produces 0 inches of thickness of trapped air, therefore providing an R-Value of '0'. Furthermore, being that it is acting as a load bearing support, I KNOW that it is against my body, so any breeze that hits it is going to effect convective cooling against the area of the UC exposed to the breeze, thereby effecting conductive cooling of my body against the area of the hammock/UC that it is exposed to. Even worse than that, is that any radiant heat is probably lost as well due to the lack of void between the 'condensation' layer.
If I alter the DIY UC to have at least one inch of void between the hammock and the wind then I cut the convective-to-conductive cooling down to a minimum, and I implement a heat transfer resistance value of 5, which only serves to enhance any R-Value provided by whatever sort of Under Quilt I choose to implement depending on the season. Plus, I also implement a void that separates my body from the condensation layer - which is always a good thing if you already sweat like a beast...
but this just may be the beer talking...
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