The most commonly used wood fuel burned is logs on open fires or woodburning stoves. Interest in low carbon fuels has increased awareness of wood pellet and wood chip installations although current applications are limited.
There are a wide range of wood types available, both hardwood and softwood, although the hardwoods are favoured by many as they burn more slowly and have a higher calorific value.
Current concerns about the effect of carbon dioxide emissions in relation to climate change has focussed attention on the zero rating of wood fuel.It is widely accepted that during their growth, trees absorb carbon dioxide from the atmosphere equal to the quantity released during combustion.
Important also are the moisture figures and the recommended periods for seasoning. The CEN/TC 335 European Standard specification states logs should have a maximum moisture content of
Seasoned in Forest - 40%
Seasoned in Storage - 30%
Oven-ready Log - 20%
Most appliance manufacturers recommend moisture levels of less than 20% for best performance. This can be achieved by splitting, stacking and air drying for a period suitable for the wood type.
Burning unseasoned wood is an inefficient practice, Much of the energy released from the fuel is used to dry the fuel and boil off the water within the core of the log.
Poorly seasoned wood results in serious problems associated with condensation in the flue. Water vapour, driven off during the combustion process, will travel up the chimney together with flue gasses. Should the flue gas temperature cool to 'dew point' the water will condense on the internal surface of the flue to form water droplets. Whilst in contact with the flue gas the water entrains some of the combustion by products to form something resembling creosote. This can seep into brickwork and cause staining and can shorton the life of a lined flue.
Tuesday, 26 May 2009
Monday, 18 May 2009
Woodburners
There’s nothing quite like a real fire – either to warm yourself by, or simply to sit gazing at – but traditional open fires have their problems.
For one thing they can be fairly dirty things to have in your living room, but with wood burning stoves, although you will have to clean them out ever week or so, gone are the days of cleaning and relaying the fire anew each morning.
Having a layer of ash gradually building up on the base actually helps the logs to burn and with their enclosed design, today’s wood burning stoves can burn round the clock, without the ever-present danger of falling logs setting fire to your house. Although soot accumulation on the glass used to be a problem, many of the modern designs also have an air-wash which cleans it for you – so you never need lose the sight of dancing flames.
Wood burning stoves are also much more efficient than an open grate fire; most of the draughts in houses with fires are caused as hot air – that you’ve paid to heat – shoots up the chimney and sucks in cold air from outside to replace it. While an open fire has been estimated to be only around 20 or 25 per cent efficient, wood burning stoves manage over 80 per cent – an instant and massive saving in energy.
For the eco-conscious, the carbon neutral nature of wood is a big bonus too. Logs are a sustainable fuel – just as long as we keep planting trees – and since they only release the “modern” carbon they took up when they were growing, unlike fossil fuels that contribute ancient carbon to the air – their net effect on the atmosphere is zero.
Pick a model with a “clean-burn” or “clean-heat" system and your heating becomes even greener. These wood burning stoves re-circulate the combustible gases given off as the wood burns, increasing the heating benefit and reducing emissions.
For one thing they can be fairly dirty things to have in your living room, but with wood burning stoves, although you will have to clean them out ever week or so, gone are the days of cleaning and relaying the fire anew each morning.
Having a layer of ash gradually building up on the base actually helps the logs to burn and with their enclosed design, today’s wood burning stoves can burn round the clock, without the ever-present danger of falling logs setting fire to your house. Although soot accumulation on the glass used to be a problem, many of the modern designs also have an air-wash which cleans it for you – so you never need lose the sight of dancing flames.
Wood burning stoves are also much more efficient than an open grate fire; most of the draughts in houses with fires are caused as hot air – that you’ve paid to heat – shoots up the chimney and sucks in cold air from outside to replace it. While an open fire has been estimated to be only around 20 or 25 per cent efficient, wood burning stoves manage over 80 per cent – an instant and massive saving in energy.
For the eco-conscious, the carbon neutral nature of wood is a big bonus too. Logs are a sustainable fuel – just as long as we keep planting trees – and since they only release the “modern” carbon they took up when they were growing, unlike fossil fuels that contribute ancient carbon to the air – their net effect on the atmosphere is zero.
Pick a model with a “clean-burn” or “clean-heat" system and your heating becomes even greener. These wood burning stoves re-circulate the combustible gases given off as the wood burns, increasing the heating benefit and reducing emissions.
Check A Trade Quotes!!!!
No we don't get involved with my builder quotes or check a trade websites. How can you give a fair quote on a chimney installation without a site survey? There are many factors to consider when pricing chimney work, every job is different and requires seperate considerations eg. access , safety, location to name a few.
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