When all "burned" to reduce heating costs, those who have turned to the privileges of biomass enjoy their choice. Biomass is a simple, economical and ecological way of heating which will never disappear.
The biomass produced each year on our planet is estimated at 172 billion tons of dry material, while in Greece, the annually available agricultural and forest residues equivalent energy with 3-4 million tons of oil, while the potential of energy crops can, under present circumstances, to overcome comfortable as agricultural and forestry residues. This amount of energy corresponds to 30-40% the amount of oil consumed annually in our country. However, by today's standards, only about 3% of its energy needs, are covered, through the use of available biomass.
A recent census has estimated that the total direct biomass available in Greece consists of approximately 7,500,000 tones of residues in agricultural crops (cereals, maize, cotton, tobacco, sunflower, canes, pomace, etc.), and by 2,700,000 tons of forest logging residues (branches, bark, etc.). Besides being the largest proportion of this biomass, unfortunately still untapped, often is a cause of many unpleasant situations (fires, difficulty performing work, spread of diseases, etc.). Inevitably, therefore, one can conclude that the use of biomass for heating and housing sector is respected proposal.
How do we evaluate the quality of combustion
Like all combustion technologies, so the domestic biomass heating systems are evaluated based on the following key features:
– The efficiency (%), defined as the ratio of the useful heat generated by the combustion system to the provided burning energy (expressed as to the lower heating value).
– The emissions from combustion, which relate mainly to various air pollutants such as carbon monoxide (CO), nitrogen oxides (NOx) and sulfur (SOx), unburned organic compounds and particulates. The main objective of any combustion system is to maximize efficiency while minimizing emissions. This can be achieved, by suitable design of the system, proper fuel selection and appropriate settings during operation, e.g. the supply of combustion air.
By definition, biomass is essentially any material that directly or indirectly has a biological (organic) origin. If the biomass used as fuel for energy production, we are talking about solid, liquid and gaseous biofuels, according to their physical form. Solid biofuels include a wide range of materials, such as pellets, firewood, pits, etc., and thei are used to generate heat in the residential sector. There is a huge variety of materials with very different characteristics that can be described as solid biofuel. In practice, the forms of solid biofuels are commercially available specific and mainly include the following:
– The pellets, are small cylindrical particles, having a typical diameter 6 – 8 mm produced from a biomass compression process. In general, the production process of pellets ensures the uniformity of the fuel and low humidity (<10 wt%). Today, the vast majority of the pellets on the market, are made of wood and characterized by low ash levels. It is also possible to manufacture pellets from other materials (eg straw), the production and use in the residential sector but their very limited due to high ash content. In the Greek market, wood pellets are usually handled in the 15 kg packages.
– The pomace is the woody residue, that comes of due to the removal of moisture and the remaining oil, the semi-solid cake remaining after oil extraction at the oil mill. The pomace is generally characterized by higher ash rates than commercial solid wood and biofuels, according to Greek law, it is imposed the oil content in dry matter, does not exceed 2%.
– The briquettes are products of biomass materials, usually cylindrical or rectangular and much larger than the pellets. Usually, they are made of wood materials and characterized by low moisture and ash percentages.
– The sawdust (or chips) of wood (wood chips) are small pieces of wood, length 5 – 50 mm. The quality of the biomass chips depends on the raw material and the production technology and usually come from forest residues (branches, tops, whole trees), residues from sawmills etc . There have no compression or a non-physical process of drying, so this usually have fairly high moisture levels which can reach 50%.
Kind of Combustion
The domestic heating systems are characterized as:
– Central heating, in which the fuel energy released by combustion in a boiler and attached to a transport carrier, which through the distribution system delivers this heat radiators properly positioned for heating of different spaces.
– Local heating, when energy is produced and attached in the same place without the intervention of a transmission system. In local heating systems include fireplaces (simple and energy fan heaters) and stoves (simple and fan heater).
Do not forget to
– Urge the technician to measure and convection after placing the chimney
– Properly clean the chimney, since improper cleaning can cause serious fire
-To be informed about the humidity of the wood before buying
– Remove any residue from previous combustion (ash, charcoal) to facilitate air circulation
+ Prevent greenhouse effect
+ Avoid air contamination from sulfur dioxide (SO2)
+ Reduction of energy dependence from oil imports of third countries
+ Ensuring labor and retaining the rural population in rural areas
+ Renewable energy source
+ Automatic fuel supply (the devices installed with this feature)
+ Low fuel costs compared with conventional fossil fuels
– Select the installation place according to the safe use of the device, the position of the chimney and the combustion air supply.
– Observe the specified minimum distance or gap (> 1 meter) from all combustible materials present around the combustion appliances (stoves, fireplaces).
– Pay attention to the installation of exhaust pipes (Burma), so as not to come into contact with wood or other combustible surfaces.
– Remove flammable materials present within 40cm from the chimney. Forbidden to pass cables in the walls or ceiling at a distance of 60cm, from the device is installed.
– Ensure that each chimney is connected to a single combustion device
– Do not place the stove on a carpet or near furniture or curtains.
– Store the wood, in a place protected from rain and ventilated (south side).
– Do not start ventilation while using the combustion device in the same room.
– Never extinguish the fire with water, especially in cast iron devices where extinguishing water can crack or break the cast iron.
– Install carbon monoxide detector in the space where the combustion device.
* Republished by www.4green.gr
Sources: Guide Solid Biofuels & Biomass Boiler for Domestic Applications Heating of the Centre for Research and Technology Hellas (CERTH), Renewable Energy Sources (CRES), Association of Greek Enterprises heating-Energy (EN.E.EPI.TH.E.)