[GSBN] Can bale buildings be air tight?- How to ventilate discussion
Chris Magwood
chris at endeavourcentre.org
Thu Mar 21 21:54:26 UTC 2013
The new book The Natural Building Companion is an excellent resource.
Contains great building science but puts it forward in a way that
newcomers can comprehend.
Chris
On 13-03-21 5:31 PM, PennElys Droz wrote:
> Hey all! Ive been loving this ventilation discussion - thank you all
> very much...notes taken, and will continue to be taken!
>
> On another thread, Im developing a sustainable construction weeklong
> hands on intensive for Native professionals and tribes. Any ideas on
> text that would be comprehensive, yet cover basics? Im looking at Dan
> Chiras' The New Ecological Home. What else? We are developing our
> own specific curriculum, but want to purchase texts for the participants.
>
> Thanks!
> PennElys Droz, Sustainable Nations
> www.sustainablenations.org <http://www.sustainablenations.org>
> pennelys at sustainablenations.org <mailto:pennelys at sustainablenations.org>
>
> On Tue, Mar 12, 2013 at 6:14 AM, John Straube <jfstraube at gmail.com
> <mailto:jfstraube at gmail.com>> wrote:
>
> The problem with airflow windows, which have been around for 30
> years or more, is that the heat recovery is only as efficient as
> an HRV during sunny hours. On a 24 hour basis in winter, the heat
> recovery (defined as the ratio of the energy content of the
> incoming temperature and outgoing air, which is leaking out
> somewhere) is not as good as a good HRV and a triple glazed
> window. If you couple these with an heat pump to extract heat
> from the air you exhaust, these systems can be equal or better
> than a good HRV.
> Of course, you need one such window in every room to get the air
> to each room.
> A good HRV with good TG windows seems a lot cheaper and a lot
> simpler...
> On 2013-03-12, at 8:40 AM, Caroline Meyer White
> <hojtpaastraa at gmail.com <mailto:hojtpaastraa at gmail.com>> wrote:
>
> > Hi there on the other side of the pond. (Is that a general North
> American expression, or just my grandmother?)
> >
> > In Denmark, a company is selling a "ventilation window". I
> attached their flyer, it has some drawings, though in Danish) It
> is developed from an old Russian type of window, where you have
> two glass panes with space in between - like 3-4 inches. The
> interior pane is a well insulated double pane, and I believe that
> the exterior is only a single layer pane. The frame is engineered,
> both being a very high quality wood for windows, but also with
> detailing breaking thermal bridges. Now the secret about it, (not
> kept) is a vent with a phase changing (I believe oil substance) at
> the top and bottom. These vents do not have any energy supply, but
> allow air to flow in between the panes FROM the out side, entering
> at the bottom, when heat is required in the building. The air is
> pre-heated between the panes and reach a temperature of average 10
> Celsius above what it was before it entered - heated by the sun
> hitting the outer pane and the heat loss going through the inner pane.
> > In summer the flow goes the other way, and the window helps cool
> down the building. The Technical University of Denmark has made
> some calculations determining that a window of the standard size
> (around 1,2 m2) on average of the four corners of the compass,
> contributes with 425 kWh / year - that is the heat gain, then
> comes the ventilation supply besides that.
> >
> > We do not have air tightness tests on SB buildings in Denmark
> yet. But this summer we are building a large residential home with
> these windows and I am very eager to see, if they will be
> sufficient to take care of the ventilation demand, as I don't know
> the air stream I haven't been able to calculate it.
> >
> > Cheers
> > Caroline
> >
> >
> > 2013/3/11 Anthony Novelli <anthony.novelli at gmail.com
> <mailto:anthony.novelli at gmail.com>>
> > Thanks Chris and August...
> >
> > August, you bring up a point that might help me clarify my
> question... I would assume in cold climate situations that very
> little humidity would be required to develop condensation on
> exterior glass, unless employing some super efficient triple pane
> with thermal breaks. Either way those surfaces will be much colder
> than an earthen plaster or wood that spreads and holds warmth.
> Part of what I'm considering is not how to eliminate the
> condensation, but rather what to do with it while it's there? Is
> there a window sill detail for the interior that could accommodate
> the inevitable moisture present? Perhaps these are already
> employed and I'm out of the loop... just seen a lot of attention
> on moisture on the outside of windows more than inside. Even with
> excellent venting it seems a good passive fail-safe.
> >
> > Best,T
> >
> >
> >
> ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Mon, 11 Mar 2013 11:00:58 -0600
> > From: August Hasz <hasz at reginc.com <mailto:hasz at reginc.com>>
> > To: Global Straw Building Network <GSBN at sustainablesources.com
> <mailto:GSBN at sustainablesources.com>>
> > Subject: Re: [GSBN] Can bale buildings be air tight?- How to
> ventilate
> > discussion
> > Message-ID: <EB70F934-A014-47AA-9BE4-03F8E2FF2884 at reginc.com
> <mailto:EB70F934-A014-47AA-9BE4-03F8E2FF2884 at reginc.com>>
> > Content-Type: text/plain; charset="windows-1252"
> >
> > All-
> >
> > First my bias: we engineer mechanical and structural systems for
> buildings. So it goes without saying see better results from
> adding a level of control and predictability. With that bias comes
> a lot of experience looking at under ventilated homes. The
> discussion about building and occupant related pollutants is a big
> factor, but misses another crucial component- condensation due to
> moisture. The building envelope may be permeable enough to
> survive, but in cold climates condensation on windows is
> unavoidable without controlling moisture in the home. In cold
> climates what we see time and time again for a remotely tight home
> (homes with 2 or 3 times the air leakage we are talking about
> here) is significant condensation build-up resulting in damaged
> materials and mold growth on surfaces. This primarily at windows
> due to the cold temps, but if there is any other location were the
> insulation detail isn't right problems will happen there as well.
> >
> > We have had a number clients/friends decide to skip the
> ventilation system over the years, and every time what ends up
> happening is they are either forced to run bathroom fans
> continuously in the winter (heat loss) or find a way to retrofit
> an HRV or ERV in. That applies to standard construction, bales,
> anything you build that is somewhat well sealed. We all know
> retrofits are expensive and to be avoided, so why leave it to chance?
> >
> > This probably is not too much of a surprise in the
> high-mountains of Crested Butte, Colorado, I assume the effect is
> worse in Chris' backyard. I was however surprised to see it is a
> big problem even in Moab. Moab is where we go to thaw our bones
> out in the middle of winter, it isn't cold right? We have been
> involved in the Community Rebuilds project happening there (If you
> aren't familiar, make sure and check out what Emily Niehaus has
> started over there, we are now starting one in our valley as well)
> and 3 homes had significant condensation on windows this winter
> resulting in a mold problem and damaged finishes. The result is
> that all future CR homes will have HRV's.
> >
> > From my perspective there is no debate: build it tight, and
> ventilate right. Relaxing the tightness of the home just leaves it
> up to chance- did I make it leaky enough for the building envelope
> to dry? enough to get the moisture out of the air? enough to get
> the result of cooking (gas combustion and lots of other
> pollutants)? It isn't' worth the risk to building occupants or to
> the building. Do we want to have a realization 10 years from now
> about health problems from a homes that seemed leaky enough, but
> oops not quite? Daily life makes pollutants, even if we are all
> watching everything we do (breathing, showering, cooking). So now
> I have a choice of how to ventilate: crack a window? exhaust fan?
> or HRV/ERV? Only the heat/energy recovery ventilator allows for
> exchanging air efficiently. The others are fighting against all
> the great work you put into the building envelope.
> >
> > My 5 cents-
> >
> > August
> >
> > _________________________
> >
> >
> > August Hasz, PE, Principal
> > LEED AP
> > Resource Engineering Group, Inc.
> > Mail: Box 3725
> > Delivery: 502 Whiterock Ave., Suite 102
> > Crested Butte, CO 81224 USA
> > Tel: 970-349-1216
> > hasz at reginc.com <mailto:hasz at reginc.com>
> > www.reginc.com <http://www.reginc.com>
> > _________________________
> > _______________________________________________
> > GSBN mailing list
> > GSBN at sustainablesources.com <mailto:GSBN at sustainablesources.com>
> > http://sustainablesources.com/mailman/listinfo.cgi/GSBN
> >
> >
> >
> > --
> > Caroline, Tahir, Noah
> >
> > Friland 11, 8410 Rønde, Denmark, tlf. (+45) 40 76 19 80
> <tel:%28%2B45%29%2040%2076%2019%2080>, skypename: caroline.meyer.white
> >
> > <Horn ventilations vindue
> katalog.pdf>_______________________________________________
> > GSBN mailing list
> > GSBN at sustainablesources.com <mailto:GSBN at sustainablesources.com>
> > http://sustainablesources.com/mailman/listinfo.cgi/GSBN
>
> John Straube
> www.JohnStraube.com <http://www.JohnStraube.com>
>
> _______________________________________________
> GSBN mailing list
> GSBN at sustainablesources.com <mailto:GSBN at sustainablesources.com>
> http://sustainablesources.com/mailman/listinfo.cgi/GSBN
>
>
>
>
> --
> PennElys Droz, M.S. Director
>
> Sustainable Nations
> PO Box 3745
> Tucson, AZ 85722
> www.sustainablenations.org <http://www.sustainablenations.org>
>
> /"If you have come to help me, you are wasting your time. But if you
> have come because your liberation is bound up with mine, then let us
> work together." Lila Watson/
>
>
> _______________________________________________
> GSBN mailing list
> GSBN at sustainablesources.com
> http://sustainablesources.com/mailman/listinfo.cgi/GSBN
--
Chris Magwood
Director, Endeavour Centre
www.endeavourcentre.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sustainablesources.com/pipermail/gsbn/attachments/20130321/47679686/attachment.htm>
More information about the GSBN
mailing list