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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    •  
      CommentAuthorKatymac
    • CommentTimeMar 2nd 2007 edited
     
    Someone (I can't remember who...sorry) Suggested a biodiesel generator for the nursery

    Is this a practical option - does it provide electricity? How would I use that to heat the nursery?

    Would it need filling like a car engine or would it be attached (like an LPG tank)?

    Any ideas?
    •  
      CommentAuthornigel
    • CommentTimeMar 2nd 2007 edited
     
    I looked into using biodiesel for my central heating.

    The problem is heating oil is about 33p per litre and biodiesel over 50p.
    This is because it can be used for car transport where it only competes because there is 20p lower duty on it than diesel.

    I think biodiesel is best used for transport and heating is best from biomass.
    • CommentAuthortony
    • CommentTimeMar 2nd 2007
     
    If you use biodiesel for heating then you must be able to either get the duty back or not have to pay it in the first place. It would be unlawful for you to have to pay this duty.
    •  
      CommentAuthorKatymac
    • CommentTimeMar 2nd 2007
     
    Wasn't someone saying that electric heating was really efficient

    Couldn't I run my GSHP on the biodiesel? then use that to heat the nursery (UFH)?

    50p a litre seems expensive - but I dont know how much I'd need to spend to run the GSHP
    • CommentAuthorTuna
    • CommentTimeMar 2nd 2007
     
    We use biodiesel that we make ourselves to heat our caravan whilst we build our house. We use hot air blowers that are sold for trucks and boats and just plumb into the diesel tank to produce hot air (lots of it). It costs us about 13p a litre to make our biodiesel - no tax is due as it's a heating fuel. The heaters come in up to 5kW sizes.

    You could run a diesel generator on biodiesel, use the electricity for lights and use the waste heat (any engine has a lot of waste heat) to heat the building. However, diesel generators are fairly big and expensive (and not always so quiet), and I've not seen one that's designed to provide domestic heat as well. That said, I'm sure something like that should exist as it's an obvious use of the heat generated.

    Converting anything to electricity is always inefficient. Electricity to heat is efficient, but biodiesel -> electricity -> heat overall is pretty poor, especially when you consider that biodiesel can be made to produce heat directly. Your best bet is to use electricity only for the necessary things - almost all successful green power generation schemes (wind turbines, solar PV etc.) start with reducing electricity consumption as much as possible before using generators.

    Do a search on 'CHP diesel' (Combined heat and power, which is what you want, and diesel generators will run on biodiesel without modification, though you might want to check with the manufacturer to ensure they are covered). You might find something interesting.
  1.  
    Blimey 50p a litre.... saw the first advert round by me for bio diesel it was 83p a litre.
    •  
      CommentAuthorfostertom
    • CommentTimeMar 2nd 2007
     
    Blimey, if you're making biodiesel for only 13p/litre then CHP makes a lot of sense, to generate your irreducible electricity requirements and use the waste heat for space heating. But if you source your electricity elsewhere it makes even more sense to burn it directly as a biofuel for space heating.
    •  
      CommentAuthornigel
    • CommentTimeMar 2nd 2007
     
    The 50p a litre is for use as fuel and excludes the road duty.

    If you then added the full duty it woud not be economic as a road fuel the 20p discount on duty offsets this.

    Clearly DIY biodiesel is the way to go if you can get hold of the used chip fat.
    But also beware a lot of chip fat is now palm oil based and in buying and using that you are encouraging the destruction of vast swathes of asian rainforest.

    Make sure its rape based otherwise it very very ungreen.
  2.  
    It's difficult to get hold of the solvent you need (methanol?) to make biodiesel, too: and if you buy it in quantities large enough to be useful then your premises will need regular inspections for safety. Don't think you'd be allowed to store it anywhere near where you're looking after children.
    •  
      CommentAuthornigel
    • CommentTimeMar 2nd 2007
     
    A friend of mine makes biodiesel commercially and has had no issues with H&S.

    The biggest problem is getting hold of the used chip fat (rape based).
    • CommentAuthorTuna
    • CommentTimeMar 2nd 2007
     
    For Katy's application, making your own biodiesel is not really an option. It's entertaining enough as a way to spend a day each month, but it consumes space, time and is a dirty process.

    To be honest, biodiesel powered CHPs are probably not an option either - unless you have the time and inclination to tinker with engines, they are not practical. You can't just press a button and reliably have energy, unless you've spent a serious amount of money on a ultra-reliable 24/7/365 set-up which I'm sure would be out of most people's budget.

    The use of palm oil is an issue, but unless you're running a commercial operation, most bio-diesel producers don't pay for their oil - they just take away oil for free. It's not encouraging chip shop owners to use palm over rape seed - that is entirely their ethical choice.
    •  
      CommentAuthornigel
    • CommentTimeMar 2nd 2007
     
    And its your ethical choice not to use it.

    If everyone refused to take away palm oil then chip shops would find it a less attractive option than rape oil.

    Its not really an excuse to blame it on them you have a choice too.
  3.  
    I agree re H&S: I'd rather not have caustic soda and methanol around 'on the shelf', but methanol is not hard to find - ask your local sppedway, grass-track or sprinting club.
    • CommentAuthorTuna
    • CommentTimeMar 2nd 2007
     
    > If everyone refused to take away palm oil then chip shops would find it a less attractive option than rape oil.

    As I said, domestic production of biodiesel really has no effect. Most suppliers of oil (whether or not it's palm oil) will take the waste oil away when they deliver fresh oil to the restaurant, so it really doesn't affect most restaurants whether or not individuals take their oil from them - it will go regardless of what type it is.

    To discourage restaurants from using palm oil, you would have to prevent palm oil suppliers from taking it away as waste - which obviously they're not going to willingly stop doing.
    •  
      CommentAuthorfostertom
    • CommentTimeMar 2nd 2007
     
    I read that there's one Pacific paradise island whose fuel is entirely supplied as used chip fat from the cruise liners.
  4.  
    You could run a generator on straight veg oil (SVO) and forget 'bio-dieselifying' it. Goat Industries had a good lot of info on SVO use when I last looked (a long time ago).
  5.  
    Maintenance nightmare though..... Unless you are a stationary diesel fanatic, you are going to be paying out for a full service every....how much would you use it? If a lot, that's a lot of service calls.
    •  
      CommentAuthorfostertom
    • CommentTimeMar 7th 2007
     
    Back in the 60s the boffins in the Kingsweston House (Vanburgh) basement at Bristol CAT (aka Bath University) School of Architecture and Building Technology were working with SMC pumps of Bridgwater to develop a tiny gas turbine a few inches long that could form part of a domestic-sized CHP or drive a heat-pump compressor with incredible fuel efficiency like 97% or something. Wonder if that could run on biodiesel?
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