[Strawbale] Volunteers for 3-layer passive insulation?
jhollan at amper....muni.cz
Thu Jul 20 00:19:20 CEST 2006
If anybody would be interested to help us much sooner, Tuesday to Thursday
(next week, July 25-27) in Hostetin, we would welcome it.
We will insulate one wall of the building (author: Georg W Reinberg) being
currently constructed there. At least 3-ply straw sandwich (40 cm thick)
will be used. Well separable layers taken from jumbo bales will be
employed, about 7 cm thick (taken as pairs in this case). At wall, they
will be separated by paper, at least each 14 cm of thickness. The purpose
of dividing straw by paper is to suppress heat transport by convection to
almost negligible values (convection takes place just inside the
individual chambers of 1/3 thickness, at 1/3 temperature drop and less
then 1/3 flow speed, so the total convection heat transport is about 1/10
of the case with just a single undivided straw layer). Such suppression is
a prerequisite to achieve passive-house U values of about 0.1 W/m2K.
The roof of the backyard building is insulated by straw already, divided
just to halves by paper (this is sufficient for horizontal insulations).
I think this is the first attempt to reach ``passive values'' reliably
with straw instead of commercial insulation materials. Don't you want to
play a role in it?
Hostetin is in eastern Czechia, close to Slovak border. It's a small
village with 280 inhabitants. A plethora of interesting environmental
projects took place there already, becoming well known in our country. An
interesting site to visit in any case.
We can offer you food and simple (basically outdoor, under shelter)
nightings. Stars are nicely visible in Hostetin, thanks to brand new
outdoor lighting retrofit using fully shielded lights (donated by
Phillips). We have a small pub there and a rather cold (but nice in hot
weather) pond on a stream just above the village.
The building site is quite busy (Skanska is the contractor), but I on
``our'' wall in the orchard we will be able to work without much
intervention by another professions.
If you would be inclined to come Monday evening and help us, please write
me off-list. I will send you further info.
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