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toggle
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tigger
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ken69
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AnneandMike
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ken69
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Nick
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toggle
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Anura
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vegplot
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resistance is fertile
Joined: 24 Oct 2008
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Location: The heart of North Devon
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Gai
Joined: 31 Dec 2004
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resistance is fertile
Joined: 24 Oct 2008
Posts: 1534
Location: The heart of North Devon
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 Posted: Sat Aug 29, 09 7:36 am Post subject: |
 
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We are doing alot of work at the moment on looking at energy efficient cooking installations, often for either designing into client's schemes or as part of 'low impact' development proposals.
The basis of many is the tremendously successful ARTI mini plant for generating gas from high calorie domestic waste. People often think biomethanisation is a complex and unreliable system, but millions of simple Chinese and Indian domestic installations would suggest otherwise.
Such systems need not be expensive, nor need they be 'Heath Robinson' contraptions which make your garden look like a hillbilly distillery.
The main benefits of the ARTI approach was that it is specifically built to use very small ammounts of high calorie feedstock (ie kitchen waste) which has an very fast digestion rate. Eg just 2kg of starchy or sugary waste can provide 500g og biomethane in little more than 24 hours (and still leave you with a greta compost ingriedient) which means that a household could cook its 3 meals a day.
The material used can be so varied as: waste grain, seed of any plant species, oilcake of non edible oilseeds, non edible or non marketable fruits (especially windfalls etc) food rests, oil rests, even the flour swept from the floor of a flour mill can be used as feedstock for the biogas plant.
Because of the small quantities and the speed of the process, size, maintenance and build costs are drastically reduced. Effectively you scale the size of the plant to meet your likely useage and you feedstock sources. A store tub of say just 20kg of suitable feedstock represents 10 days fuel reserves.
The apparatus itself consists of a very simple construction that can be installed next to your compost heap, taked away in the garden or ideally buried below ground, which given its reasonably small size is not a massive engineering effort.
-Two plastic water tanks sold in sanitary and plumbing shops. One should be bigger than the other so that once the top of each tank is cut open, the smaller one can fit in the bigger one and move like a "telescope“. The bigger tank (or drum) serves as a digester, and the smaller, placed upside down in the bigger one serves as the gas holder.
-The inlet pipe: a 3cm diameter flexible pipe, a bit longer than the height of the tank, is fitted at the bottom side of the bigger tank. At the free extremity of the pipe , a funnel is fixed to facilitate the pouring of the quite fluid feedstock material. The pipe with the funnel are to be fixed loosely to the top of the tank, in upright position. This pipe will also serve as a purge.
-The effluent outlet is fitted to the upper part of the bigger tank and determines the maximum level of matter in the tank.
-The gas outlet is fitted to the smaller inner tank and directed toward a gas stove.
-a frame structure is build above the tanks to stop the gas tank being able to fall open if it is accidentally overfilled. A weight is themn placed on the smaller tank to set the pressure under which the gas is held in the tank.
-The set up, if not buiried can then be insulated with any practical insulative cladding or small shed arrangement to ensure that the digestion is assisted by stable temperatures.
Methane burns with a blue flame, without producing any smoke or soot and has a calorific value of Town Gas. The small amount of solid residue produced by the biogas plant makes a good fertiliser. Methane, unlike propane, is lighter than air, there is therefore little risk of an accumulation and explosion in case of a leak.
We are installing a biomethane plant here to heat or large greenhouse (and provide supplementary gas supply to the kitchens). Once it is completed we hope it will provide a clear working example that people will be able to see in action. We are also installing communal systems in two of the low impact village developments that we are working on.
The other main area we have been looking into is solid biofuel burners, used for cooking, heating and hot water provision combined with a surprisingly small and simple to manage coppice area, under rotation, to give people full independence in fuel energy. I will find the figures for this later and post it all up. |
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Green Rosie
Joined: 13 May 2007
Posts: 10498
Location: Calvados, France
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sean
Downsizer Moderator
Joined: 28 Oct 2004
Posts: 42219
Location: North Devon
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resistance is fertile
Joined: 24 Oct 2008
Posts: 1534
Location: The heart of North Devon
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