[Strawbale] [SB-r-us] re: Passive Heating

[activism98201 at verizon.net]

Solar energy IS and ALWAYS (dare any government to try otherwise) free.  Wood, unless one has his/her own forest is likely to go up in cost as mineral fuels rise in scarcity/cost; demand for wood will go up, which means that if you did have your own forest you might face risking the loss of some self discipline (sell too much of your own wood), or someone else's self discipline might come in to play (theft of your wood).

I followed many of Loren's ideas some time back, but if I recall correctly he never implemented the 2L bottle idea.  I'd personally feel a bit timid about being a guinea pig on such an important issue.

I'll still state that there's more energy required to move air than you might think.  Consider all that ducting; and also think about multiple ducts to distribute that air. How expensive is all this ducting and fans (and necessary electrics- off grid?  better factor in the PV costs) etc.?  I'm sure that there's an HVAC person lurking around here that might be able to shed some more light on this subject.

At one point I had started to sketch out some designs using Loren's idea but I struggled: not like this would be a surprise, I struggle with _everything_! :-)

Gary Rysa has done a lot to passive air and hydronic stuff.  I know that Mother Earth News has published some of his articles.

Hydronics aside, I am still an advocate for passive thermal mass solutions.  Mass heated with true free energy- the sun.  Once in place that's it, no maintenance of any kind (except chasing dust bunnies).  Are slabs THE solution, no; other solutions are likely better for other situations.


Mark Nagel
Everett, WA


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From: Shody Ryon <qi4u at yahoo.com>


There are so many variables in slab prep and design. I
wish it was straight forward and simple. I was on a
job where a slab was poured on an underground spring,
what a mess.

The smallest piece of under slab 15 mil plastic I can
find costs $700, bringing the cost to about $1200 more
for the slab.

Laren claims the on going cost of heating a house with
a slab is higher than wood (cost could mean amount of
solar energy), therefor the on going operational cost
is included in the lower cost of wood.

The amount of electrical energy used to move the air
from a thermal attic to a living space in a single
level house is very low. Multiple levels I do not know
about, but he commonly designs multilevel houses, so I
assume it would be energy efficient also.

He has addressed this issue recently stating that if
even lower electrical requirements are wanted or
needed, such as for an off-grid project, cycling water
would use a lot less energy. I do not know if this
ultra low energy system could circulate water through
a hydronic system as energy efficiently also, I doubt
it, but it wouldn't take a lot of engery, generally
speaking, to circulate it as the circulation of the
water through the system is not usally an issue accept
in drain back systems.

Part of the idea is to have the solar collection area
uninsulated on the collection side and the thermal
storage and living area insulated. This sounds
obvious, but a lot of designers might get mixed up
with this. This requires transferring warm and cool
from an uninsulated area to an insulated area
efficiently and distributing it in the living space.

The 2L thermal storage system is designed to be easy
to use, low maintenance; daily and over time, energy
efficient, little consequences from neglect, low
initial cost, not much down side. I haven't seen or
used one so all this is is recycled internet info.


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