[Greenbuilding] Aggressively Passive: Building Homes to to the Passive House Standard

[John Daglish]

Bonjour John


Friday, January 28, 2011, 4:43:34 PM, you wrote / vous ecrirez:

JS> Yes, I think this is part of the problem.  I have the PHPP 2007, having paid my money several years ago and have used it
JS> As I have said, it is a very good spreadsheet.
JS> There are many programs like PHPP that have been developed and calibrated with houses in North America too (and Sweden, UK, etc).
JS> The CEPHEUS reports show that it is about is accurate (or inaccurate, as the results are +/-50%) as other programs.  No better, sometimes a little worse than many other programs. We regularily
JS> use hourly programs for the design of all our low-energy houses since they are easy to use and fairly accurate.
JS> I am well aware of the requirements of PH.  

I think it is a little bit better than that if you look at the graphs
and read the report, the high outliers being due to equipment not working.

Cephus project measured results, you can read the report here
http://www.passivehouse.com/07_eng/news/CEPHEUS_final_long.pdf

JS> The questions are "Why"? Where is the scientific justification for 10W/m2?  And the 4 C asymmetry? Why?
JS> I understand these are edicts from Darmstadt, but I would like to understand the science so that I can explain and modify the results for other climates.

You know why, you state it in your articles, you are being extremely
polemic.  Maybe US Passivhaus have been dogmatic but I have always
stated in my comments to this group that it is applicable to similar
climates in the US.

When you get outside this range you have to adapt as is shown in the
PassivOn project of calibrating default elements to specific climates
and in any case there is the PHPP software that can tweak the different elements.

eg. the PassiveOn project has been calibrated for some European climates.
www.passive-on.org

The radiant surface temperature  asymetry should
be less than 4C eg window 15C wall 20C. Otherwise convection courants
develop leading to discomfort, leading to ... putting on the heater.
http://passipedia.passiv.de/passipedia_en/basics/building_physics_-_basics/thermal_comfort/local_thermal_comfort
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2V-4NN0W94-1&_user=10&_coverDate=12%2F31%2F2008&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1622891925&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=5fa958f8c400ef770fef5672daaa9a37&searchtype=a

regards

John Daglish

JS> On 2011-01-27, at 1:02 PM, John Daglish wrote:

>> Bonjour jfstraube,
>> 
>> The PassivOn project has been calibrated for some European climates.
>> www.passive-on.org
>> 
>> But using the PHPP planning package (15 or so linked excel
>> spreadsheets) with your monthly climate data you can modulate the u
>> values, etc. which does a fair stab at it for a static /steady state
>> calculation provided
>> you take into account the minimum requirements eg 10W/m2 max heat/cool load,
>> asymetric radiant temperature différences less than 4C, etc.
>> The PHPP package is correlated against constructed project operational
>> data * and
>> the PHI Passiv Haus Institutes inhouse dynamic (hourly) calculation
>> program.
>> 
>> * eg. Cephus project measured results
>> http://www.passivehouse.com/07_eng/news/CEPHEUS_final_long.pdf