[GSBN] Embodied energy comparisons: SB vs Stick-built
jswearingen at skillful-means.com
Mon Feb 16 13:01:48 CST 2009
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:
1. Does the material contribute structurally
2. Does the material contribute thermally (insulation)
3. Does the material provide thermal storage (mass)
4. Does the material provide fire safety
5. Does the material contribute to the local economy
6. What are the manufacturing environmental costs
7. What are the transportation and wastage environmental costs
8. Is the material a by-product, waste-product, or recycled
9. Is the material bio-degradable, recyclable or land-fill
10. Is the material toxic in manufacture, use or disposal
11. What is the expected life-span of the system (resistance to
Feel free to add.
On Mon, Feb 16, 2009 at 10:34 AM, RT <ArchiLogic at yahoo.ca> wrote:
> 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:
> " ... from the seminal paper done by Cole and Kernan years ago
> ==========copied material =============
> The data shown here represent average operating energy consumption between
> Vancouver and Toronto climatic conditions, assuming conventional levels of
> envelope and equipment energy efficiency.
> The initial embodied energy remains constant at 4.82 GJ/m2 over the 50
> year period which was examined, while the recurring embodied energy
> increases from zero at the time of building completion, to a cumulative
> value of 6.44 GJ/m2 by year 50. The operating energy eclipses both forms
> of embodied energy at a cumulative value of 70.28 GJ/m2 and represents
> just over 85% of the total energy at the end of the 50-year period.
> This relationship has prompted some practitioners to conclude that
> embodied energy is comparatively irrelevant. However, as the level of
> operating energy efficiency is improved, the contribution of embodied
> energy to total energy becomes more significant.
> =======end of copied material ========= "
> And on the subject of tools for evaluating environmental impact, another
> excerpt from a recent message posted to the same list:
> ========= copied material ============
> ... under the auspices of Canada Mortgage & Housing Corp (
> www.cmhc-schl.gc.ca) a spreadsheet
> application "OPTIMIZE" was developed to
> "...assist building researchers and designers in estimating the
> life-cycle energy,
> material flows and environmental impact of residential assemblies and
> -- essentially a means to evaluate the Green-ness of a proposed design and
> do the necessary tweaking at the design stage (ie before the mistakes have
> been concretised in the Real World).
> The output, in chart & table form, using recognisable English where text
> was used, provided
> - breakdowns for energy flows, both embodied and life-cycle
> ie energies of materials aquisition,operating,
> construction, demolition, disposal/recovery, fuels)
> - AsBuilt & Life Cycle Embodied Energy & Weight Breakdown by
> Commodity for a list
> of about 60 material types
> - Breakdown of Air Emissions and External Costs
> -Breakdown of Indoor Air Pollutants
> -Breakdown of Outdoor Emissions with weights for each and their $
> itemised for CO2, particulates, NOx, SO2, VOCs, Methane,CO,
> Cadmium, Chromium,Copper,Mercury (blah,blah,blah,) ... Nuclear,
> ...with a dollar cost per person housed as the last line of output.
> OPTIMIZE made its appearance well over 15 years ago and no doubt, there
> have been a number of similar software programs put out there since then.
> ============ End of Copied Material ============
> 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".
> 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.
> 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.
> That is to say, a comparison such as that suggested by Joyce would probably
> be meaningless.
> 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
> === * ===
> Rob Tom
> Kanata, Ontario, Canada
> < A r c h i L o g i c at ChaffY a h o o dot C a >
> (manually winnow the chaff from my edress in your reply)
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