[Strawbale] PEX, Concrete Slab, Fear of Death (by contractor)

[Shody Ryon]

--- Sherwood Botsford <sgbotsford at gmail.com> wrote:
> Water is heavy. To get significant water in the
> attic space requires a 
> much more robust roof structure. 

Laren went through this with someone. He said the
weight of water is insignificant in a “to code” built
structure. He said they are designed to hold the
weight of SUVs parked door to door (the SUVs doors, I
imagine) and bumper to bumper and backs that claim up
with numbers, which I will cross post if I can find
it.

> And while water is cheap, containers 
> to keep it for 50 years or so are not.  I would not
> advise putting it in your roof.

I think Laren's ideas are all about well thought out
highest most efficient quality, least cost, least
daily input, least negative consequences due to
neglect and failure. High density polyethelene (HDPE)
has a long track record of competent water
containment. Its weakness is (UV?) light, which the
thermal attic system does not subject the bottles to.
Although he recommends PET bottles, I assume PET is a
close relative of HDPE and PEX, plenty good enough for
most folks on this list. Gatoraide is said to produce
the highest grade of 2L PET bottle for those that need
this, though I wouldn't consume what comes inside.
Secondly, what is the likelyhood of all the bottles
failing at once? Perhaps if a comet hit the roof, in
which case a little extra water might be a good thing,
try not to beath the fumes from the melted plastic
though ;-0 one at a time failure is not a big deal.
They tend to develop slow leaking pin hole leaks
anyhow.

> Put the water in a tank under the house. 

Laren is suggesting the flexible large plastic bag
style cisterns in the crawl space of wood floor houses
for rain water collection and temperature tempering
from below the floor as a secondary thermal
storage/temper. He is not a fan of air circulating
through vented crawl spaces, which I don't fully
understand yet, but that is another subject.
 
> If you want to harvest attic 
> heat, run a circuit of tubing between that tank and
> the attic space.

A circuit of what?

> Dirt is even cheaper than water+container.  A cubic
> foot of water has 
> about the same thermal storage as about a half cubic
> foot of water. 
> (Rough calc:  Dirt has a specific heat of about 0.2,
> but a density of 
> about 2.5)

The issues I have with dirt is that the system to
charge it can be energy intensive requiring moving
massive amounts of earth and tubes. They are hard to
retro fit, can be prone to fungus. A fair amount of
time, energy for a system with half the storage per
volume. The thermal attic is recharged every time the
house is heated by any source, due to thermal
striation. Laren suggests equator facing sun spaces to
collect heat for the house too. The systems can all
work together as well as small portable very high
efficiency heat pump to extract extra heat from the 2L
water bottles if needed, or a wood or pellet stove
would work or any other system too.


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