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Green Building Bible, Fourth Edition
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Renewable Energy: Fuel for the 21st Century?

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    •  
      CommentAuthorDamonHD
    • CommentTimeJan 30th 2012
     
    You first... %-P

    Rgds

    Damon
    • CommentAuthorJoiner
    • CommentTimeJan 30th 2012
     
    Yeah, sure. Then turn around and find no one else there? Met your sort. :smoking:
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 30th 2012
     
    Posted By: Joinermeddling

    Meddling or Fiddling in public spaces, I think one is illegal now :smoking:
    • CommentAuthorJoiner
    • CommentTimeJan 30th 2012 edited
     
    Only if you photograph yourself doing it. :cool:
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 30th 2012 edited
     
    Taking the pictures is OK, posting them on here is where the trouble starts I find:threesome:

    Edit:
    What does GBF stand for again
    • CommentAuthorJoiner
    • CommentTimeJan 30th 2012
     
    :bigsmile:
  7.  
    http://thinkprogress.org/romm/2012/02/05/418574/solar-panels-from-grass-clippings-biophotovoltaics/
    A new twist on green roof/energy/pv threads but efficiency a "wee" bit low at stated .1% !!
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 7th 2012
     
    0.01% actually! How does that compare with a living plant?
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 7th 2012 edited
     
    <blockquote><cite>Posted By: fostertom</cite>0.01% actually! How does that compare with a living plant?</blockquote>

    Plants convert around 7 or 8% of the solar energy falling on them into potential energy in their tissue, on average. Some can do a bit better, but all fall short of the efficiency of PV by a fair margin.
  10.  
    Apologies for typo Tom, currently suffering keyboard problems(mainly down to operator!). Agree living plant better than dead one and raises point is it better to cut grass and utilise it for energy or allow it to grow wild?.
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 7th 2012
     
    Posted By: JSHarrisPlants convert around 7 or 8% of the solar energy falling on them into potential energy in their tissue, on average
    That is astonishingly high, when you consider that an oak tree has 4 acres of leaf surface; a rainforest giant 14 acres. And those acres of collector are soaking up solar radiation round the clock for a long lifetime.
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 7th 2012
     
    <blockquote><cite>Posted By: fostertom</cite><blockquote><cite>Posted By: JSHarris</cite>Plants convert around 7 or 8% of the solar energy falling on them into potential energy in their tissue, on average</blockquote>That is astonishingly high, when you consider that an oak tree has 4 acres of leaf surface; a rainforest giant 14 acres. And those acres of collector are soaking up solar radiation round the clock for a long lifetime.</blockquote>

    That's during their active growth phase though, not through life. Conversion ratios slow down a lot once the plant is mature, I believe.
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 7th 2012 edited
     
    Hence the argument that it's best for atmospheric CO2 levels to fell mature forests and replant with young, vigorous trees. As long as the old timber is not burnt, composted, left to rot or otherwise re-oxidised back to CO2 but instead sequestered warm dry and rotproof e.g. in building structure - or converted to charcoal (with take-off of hydrogen content as useful harmless fuel) and buried. The latter is coincidentally great for soil texture, stability and slow release of minerals.
    • CommentAuthorpmagowan
    • CommentTimeFeb 7th 2012
     
    I don't suppose charcoal could be used as an insulation material? It certainly feels very light and airy. The problem would maybe be that carbon is quite conductive. It would be a good way to store it so that it remained sequestered. Maybe a fire risk too, probably mad now I think about it.
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 7th 2012
     
    Thermal conductivity of charcoal, I haven't found - but it's fairly non conductive (fair insulator) because expecting structural timber to char (at a known rate in mm of thickness per min) in a fire, allows the resultant insulating layer to protect the remaining timber; hence char is a recognised form of structural fire protection.

    Anyone got the figure? It cd be a great idea for insulation with sequestration. Like Warmcel shredded newspaper, it sounds combustible but no so much in a mass lump, and can be treated with flame retardant.
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 7th 2012
     
    Carbon is 1.7 W.m^-1.K^
    Air is 0.024 W.m^-1.K^

    If you know the density, can then work out the overall conductivity.
    • CommentAuthorJoiner
    • CommentTimeFeb 7th 2012
     
    I know a few people with high overall conductivity then. :wink:
    •  
      CommentAuthorfostertom
    • CommentTimeFeb 7th 2012 edited
     
    Posted By: SteamyTeaIf you know the density, can then work out the overall conductivity.
    go on then?
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 7th 2012
     
    Not giving arithmetic lessons today, tied up with thermal/energy response times due to solar gain.

    Go find the data on the density of carbon, air (about 1.2 kg.m^-3) and charcoal and I may have time later.
    • CommentAuthorSeret
    • CommentTimeFeb 7th 2012
     
    Posted By: pmagowanI don't suppose charcoal could be used as an insulation material?


    I'd pay good money to watch a fire in a house insulated that way!

    I'd also stand well back.
    • CommentAuthorpmagowan
    • CommentTimeFeb 7th 2012
     
    A throw a couple of sausages on !
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 7th 2012
     
    Smelt some tin, could call it blowinghouse :wink:
    • CommentAuthorDavipon
    • CommentTimeFeb 12th 2012
     
    Interesting article it Sunday Times today re using seaweed as a bio fuel!
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 12th 2012
     
    A few years ago I suggested on an renewable energy course that we get an old oil tanker, fill it with seaweed, float around the Pacific for a few months, then motor into port and off load a load of biogas. I really should have done it :surfing:
  25.  
  26.  
    http://www.guardian.co.uk/environment/2012/mar/01/device-sewage-plants-power-stations
    This appears to be a good idea for waste to energy but checking data on solids created indicates 55g/pp/day =20kg/yr = 18KWh. Existing proven AD EFW process would appear to provide better option !!!
  27.  
    Interesting mix, but large coal fired proposals cause concern.
    http://uk.reuters.com/article/2012/04/23/power-germany-plants-idUKL5E8FN6R220120423
  28.  
    Who is telling the truth and what is the future for oil? I note an interesting reference to Iraq !

    http://www.guardian.co.uk/commentisfree/2012/jul/02/peak-oil-we-we-wrong
    •  
      CommentAuthorSteamyTea
    • CommentTimeJul 3rd 2012
     
    Seems I was right :wink:
    •  
      CommentAuthorDamonHD
    • CommentTimeJul 3rd 2012
     

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