Ok, since we've decided that embodied energy is of less or equal significance as life-cycle energy use, I would suggest that any materials or forms of construction be evaluated on at least these areas:<br><br><ol><li>Does the material contribute structurally</li>
<li>Does the material contribute thermally (insulation)</li><li>Does the material provide thermal storage (mass)</li><li>Does the material provide fire safety</li><li>Does the material contribute to the local economy</li>
<li>What are the manufacturing environmental costs</li><li>What are the transportation and wastage environmental costs</li><li>Is the material a by-product, waste-product, or recycled</li><li>Is the material bio-degradable, recyclable or land-fill</li>
<li>Is the material toxic in manufacture, use or disposal</li><li>What is the expected life-span of the system (resistance to environmental damage)<br></li></ol>Feel free to add. <br><br>John<br><br><br><br><br><br><br><div class="gmail_quote">
On Mon, Feb 16, 2009 at 10:34 AM, RT <span dir="ltr"><<a href="mailto:ArchiLogic@yahoo.ca">ArchiLogic@yahoo.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
By way of putting some numbers to what Andrew was talking about earlier WRT life cycle cost dwarfing embodied energy cost, an excerpt from a recent post to the REPP/CREST Greenbuilding List:<br>
<br>
<a href="http://listserv.repp.org/pipermail/greenbuilding_listserv.repp.org/2009-January/009751.html" target="_blank">http://listserv.repp.org/pipermail/greenbuilding_listserv.repp.org/2009-January/009751.html</a><br>
<br>
<br>
" ... from the seminal paper done by Cole and Kernan years ago<br>
==========copied material =============<br>
<snip><br>
The data shown here represent average operating energy consumption between<br>
Vancouver and Toronto climatic conditions, assuming conventional levels of<br>
envelope and equipment energy efficiency.<br>
<br>
The initial embodied energy remains constant at 4.82 GJ/m2 over the 50<br>
year period which was examined, while the recurring embodied energy<br>
increases from zero at the time of building completion, to a cumulative<br>
value of 6.44 GJ/m2 by year 50. The operating energy eclipses both forms<br>
of embodied energy at a cumulative value of 70.28 GJ/m2 and represents<br>
just over 85% of the total energy at the end of the 50-year period.<br>
<br>
This relationship has prompted some practitioners to conclude that<br>
embodied energy is comparatively irrelevant. However, as the level of<br>
operating energy efficiency is improved, the contribution of embodied<br>
energy to total energy becomes more significant.<br>
<snip><br>
=======end of copied material ========= "<br>
<br>
*<br>
And on the subject of tools for evaluating environmental impact, another excerpt from a recent message posted to the same list:<br>
<br>
<a href="http://listserv.repp.org/pipermail/greenbuilding_listserv.repp.org/2009-February/010158.html" target="_blank">http://listserv.repp.org/pipermail/greenbuilding_listserv.repp.org/2009-February/010158.html</a><br>
<br>
<br>
========= copied material ============<br>
... under the auspices of Canada Mortgage & Housing Corp (<a href="http://www.cmhc-schl.gc.ca" target="_blank">www.cmhc-schl.gc.ca</a>) a spreadsheet<br>
application "OPTIMIZE" was developed to<br>
<br>
"...assist building researchers and designers in estimating the life-cycle energy,<br>
material flows and environmental impact of residential assemblies and buildings"<br>
<br>
-- essentially a means to evaluate the Green-ness of a proposed design and<br>
do the necessary tweaking at the design stage (ie before the mistakes have<br>
been concretised in the Real World).<br>
<br>
<br>
The output, in chart & table form, using recognisable English where text<br>
was used, provided<br>
<br>
- breakdowns for energy flows, both embodied and life-cycle<br>
ie energies of materials aquisition,operating, maintenance/replacement,<br>
construction, demolition, disposal/recovery, fuels)<br>
<br>
- AsBuilt & Life Cycle Embodied Energy & Weight Breakdown by Commodity for a list<br>
of about 60 material types<br>
<br>
- Breakdown of Air Emissions and External Costs<br>
<br>
-Breakdown of Indoor Air Pollutants<br>
<br>
-Breakdown of Outdoor Emissions with weights for each and their $ co$t<br>
itemised for CO2, particulates, NOx, SO2, VOCs, Methane,CO, Arsenic,Beryllium,<br>
Cadmium, Chromium,Copper,Mercury (blah,blah,blah,) ... Nuclear, Hydro<br>
<br>
...with a dollar cost per person housed as the last line of output.<br>
<br>
OPTIMIZE made its appearance well over 15 years ago and no doubt, there<br>
have been a number of similar software programs put out there since then.<br>
<br>
<snip><br>
============ End of Copied Material ============<br>
<br>
<br>
But back to Joyce's original query about embodied energy comparisons of stick-built ve SB, as Andrew pointed out, it's like asking "how long is a piece of string".<br>
<br>
I would venture that one of el Lupo's (aka John Glassford) earthen-plastered, loadbearing SB houses in Australia is several magnitudes lower in embodied-energy than one of his twin-brother-by-different-mothers (aka the Skillful Meany) Portland cement plastered, seismic-resistant SBH on a thickened-edge reinforced concrete slab foundationed California SB houses.<br>
<br>
I would further venture that I could build a stick-framed house that is more energy-efficient and lower in embodied energy than either. But I could also build one that is higher in EE as well.<br>
<br>
That is to say, a comparison such as that suggested by Joyce would probably be meaningless.<br>
<br>
It would be more useful I think, to simply provide charts (North American, European, Aus/NZ sourced ) of the embodied energies of the most common materials that are used in making a SB house and show a sample calculation as to how to use the numbers, showing the same calculations for a "typical" Green-built, stick-framed home for the sake of comparison so that the reader will have an inkling of where her design stands in the embodied-energy spectrum.<br>
<font color="#888888">
<br>
<br>
-- <br>
=== * ===<br>
Rob Tom<br>
Kanata, Ontario, Canada<br>
< A r c h i L o g i c at ChaffY a h o o dot C a ><br>
(manually winnow the chaff from my edress in your reply)<br></font><div class="WgoR0d">
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