Archive for March, 2010

Bio-Mass Fuels

Other fuels include bio-gas (methane) from anaerobic digestion of food and slurry waste.

Liquid bio-fuels like bio-diesel from rapeseed oil or flexi-fuel like bio-ethanol from creamery waste whey or cellulosic wood based feedstock, producing second generation ethanol. Importing ethanol or bio-diesel is not a good solution. It is often made from corn which is very energy intensive and CO2 emitting. It can cause deforestation to rain-forests and food and water shortages in poor countries. It also means importing this fuel like our oil, gas and coal.

Wood-Chip as a source of biomass in Rural Ireland

The next fuel to consider if living in rural Ireland is wood-chip. If you are lucky enough to have thinning available from forestry or land to grow short-rotation, coppice- willow. After harvesting, the wood is first left stacked and covered to air-dry sufficiently. It’s typically dried for at least the six warmer months of the year. It is then chipped and stored. If it’s not dry enough it may ferment and heat up like compost, so needs to be turned. The damper it is, the less efficient and wasteful to burn with more gas emissions. It is therefore critical to reduce its moisture-content down to around 25degrees Celsius.

Heat Energy solutions for homes – sourced from Biomass

In my last blog I discussed the use of solar collector systems for generating renewable, zero-CO2 emissions, domestic hot water and space heating for Irish homes. I also showed some solutions for heat pumps. This time, I wish to explore the potential and options available from various biomass sources and their appropriate heating appliances and systems.

The first renewable fuel to consider is wood, which is the most common traditional fuel for heat from the early times of hunters and gatherers. -Typically used as dried wood branches and split logs. The drier the wood the more efficient in producing heat. If wood is damp, a huge portion of the combustion heat is absorbed by evaporation and wet wood is difficult to generate enough heat to dry before it can heat sufficiently to form a gas vapour from the wood fuel, so as to ignite in the presence of oxygen. Some species of wood burn better, are denser and contain a higher calorific value than others.