[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: GSBN:FW: 3-layer passive insulation?

So would I. I'll send an email to Jan Hollan and see what additional
information I can share.


on 7.20.2006 10:10 PM, Derek Roff at derek@...:

> I don't think I understand the material described.  As I envision the
> straw/paper sandwich, I have trouble understanding how it will work.  It
> sounds like there will be multiple straw-to-paper-to-straw interfaces.
> This would imply that no straw connects the inside to the outside of the
> bales.  How are the different layers held together?  Are the inside and
> outside surfaces plastered?  Does the plaster key into a layer of straw?
> To what extent can this design act as a stressed-skin panel?
> Like John, I have doubts about the convection question.  Convection is a
> gravity-driven, largely vertical phenomenon.  It seems odd that vertical
> divisions within the wall would have a major effect, and even more odd that
> the paper dividers are said to be less important in horizontal insulation.
> I would love to hear more information.
> Derelict
> Derek Roff
> Language Learning Center
> Ortega Hall 129, MSC03-2100
> University of New Mexico
> Albuquerque, NM 87131-0001
> 505/277-7368, fax 505/277-3885
> Internet: derek@...
> --On July 20, 2006 11:33:36 AM -0700 John Swearingen
> jswearingen@... wrote:
>> Sounds interesting.  Also sounds like a lot of work.  I wasn't aware that
>> convection within the bales was so problematic.  Then again, we have very
>> tight, dense bales, and it would seem that breaking them into flakes would
>> lower the density more than paper would help convection.
>> Sorry I can't make it to Czechia this weekend to help out.
>> John "Flakey" Swearingen
>> John Swearingen
>> design and construction
>> www.skillful-means.com
>> -----Original Message-----
>> From: GSBN [<a  target="_blank" href="mailto:GSBN@...";>mailto:GSBN@...] On Behalf Of Joyce
>> Coppinger Sent: Thursday, July 20, 2006 10:14 AM
>> To: GSBN
>> Subject: GSBN:FW: 3-layer passive insulation?
>> Has anyone heard of or used the three-layer passive insulation method? Any
>> comments about it's effectiveness?
>> Joyce
>> -------
>> ----------
>>> From: Jan Hollan jhollan@...
>>> Reply-To: European strawbale building discussions
>>> strawbale@...
>>> Date: Thu, 20 Jul 2006 00:19:20 +0200 (CEST)
>>> To: European strawbale building discussions
>>> strawbale@...
>>> Subject: [Strawbale] Volunteers for 3-layer passive insulation?
>>> 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.
> ----
> For instructions on joining, leaving, or otherwise using the GSBN list, send
> email to GSBN@...HELP in the SUBJECT line.
> ----