– Wood pellet boilers make use of what is probably the most convenient fuel in a home setting. It is necessary to manufacture the fuel, so it is not the same as natural wood, but with a maximum water content of 10% and a high density, there is less storage space needed, lower transport costs, and higher boiler efficiency – around 90%.
Modern wood-fuelled boilers use thermostats to regulate the amount of fuel and air that is taken in the past there have been concerns about the controllability of wood-fuelled heating but these have now been solved. Bear in mind that all biomass boilers burn most cleanly and efficiently when working at their maximum output, so choosing one with the right energy requirements is vital. There are a number of factors to consider when choosing a wood-chip boiler.
– You will need to figure out the amount of energy you need for your house before deciding to install a new boiler because wood-chips as a fuel are more suitable for larger farmhouses or even industrial buildings, etc. These boilers are automated and need extensive fuel handling systems and storage facilities which might not be cost-effective for a small domestic installation.
– Sourcing a good supply of wood-chips is essential in terms of both quality and locality. Moisture content in the wood-chips need to be about 25% or less, though some boilers are especially made to handle up to 40% moisture content. Obviously, the lower the % the more efficient the boiler will be. On the other hand, finding a local source of wood-chips should be possible, which reduces transport costs, helps to promote local woodland management and support the local economy.
– Price-wise, a 40 tonne of air dried wood chip ((25%) moisture content) produces the same amount of energy as heating oil at 9.8p per litre.
Installation of a wood-chip boiler could cost in the region of 5,000.
For pellets, the drawback is that getting hold of a pellet provider in the UK is difficult, with most being imported. Pellets are also expensive- certainly more expensive than wood-chips even taking into account the moisture content. However, pellets do make operating a boiler incredibly easy, with cleaning required only once a month and the ash-tray emptying between once a month/year. It is important to consider costs of storage and transportation, as well as the fuel itself, when deciding whether wood pellets would make a suitable fuel for your boiler.
There follows a list of Wood-Chip boilers and then a List of Pellett Boilers
1) The Ecoenergy KWB Multifire/USV Range is fully automated and designed for domestic use. Standard features include automatic ignition, boiler cleaning, & ash and soot extraction, making the KWB essentially maintenance free between annual servicing. They offer the following models (from http://www.econergy.ltd.uk/products.html): USV D (15 100 kW) with 10 litre hopper, USV ZI (15 100 kW) with 200 litre hopper, USV V (15 40 kW) with 1,000 litre hopper. From http://www.renewable-resources.com/biomasswoodchipboilers.htm.
2) Talbott’s Biomass C Range is also desinged for domestic use. C1-B Model (50kW) is probably most appropriate. All of these boilers are self-cleaning and accept a variety of fuels. F rom http://www.talbotts.co.uk/cbiom.htm.
3) The Arimax range of boilers from Bioenergy Technology Ltd. Arimax 340 (20-50kW). From http://www.bioenergy.org/:
4) Dragon range of double pass water heaters. From http://www.dragonheat.co.uk/
5) Moderator Boilers (12-600kW) are a low-temperature heating boiler (up to 95 deg.c) suitable for domestic and industrial installations. Include blower/fan system and temperature control. From http://www.dunsterwoodfuels.co.uk/moderator.html.
6) Vigas (25 – 80 kW) range for domestic and commercial use. All the boilers employ the latest “gasification down burning” technology and have sophisticated electronic controls that ensure maximum efficiency and minimum emissions. Models 25-40 are eligible for grant aid under the Clear Skies programme. From http://www.dunsterwoodfuels.co.uk/vigas.html.
7) Gilles Woodchip Systems (10kW to 145kW). Suitable for woodchips, pellets, sawdust, woodshavings. Cell wheel technology eliminates risk of burn back and regulates chip size. All models come with automatic heat exchanger cleaning. Automatic de-ashing as standard. Heavy duty ash agitator to break up any clinker build up. Prices start from 7,000. From http://energyinnovationsuk.com/gilles/woodchip1.htm.
8) MULTIHEAT boiler (15-40kW).
Very high efficiency: 89-91%. Multifunctional digital control provides simple operation with continuously variable heat output from 30-100%. The boiler does not require a storage tank. Exposed parts of the combustion chamber are constructed in acid-proof, stainless steel. From http://www.fbcgroup.co.uk/baxi.html#MULTI%20HEAT.
9) REKA boilers. From http://www.riley-reka.co.uk/tech2.htm
10) REFO woodchip/biomass boiler automatic (10 – 120kW). From http://www.farm2000.co.uk/refo.htm.
Providers of wood pellet boilers in the UK and their ranges are listed below:
1) Kunzel Pellet Boilers, available in 15kW and 25kW. Both types have an integral 220litre hopper enough fuel for up to one week. From http://www.ashwellengineering.com/boiler_range.htm.
2) GREEN – TEC pellet boilers (15kW – 1.2MW). Efficiencies of >90%. Boilers up to 75kW are fitted with intergral hoppers. From http://www.ashwellengineering.com/boiler_range.htm.
3) Combifire2 Wood pellet boiler has an efficiency of 90.8% and comes complete with an auto-start, burner head and an external feeding screw. This system allows to choose many different positioning solutions for the unit and the pellets. There are also two optional hopper sizes for this boiler – 300 and 500ltr. From http://www.bioenergy.org/.
4) Woodpecker wood pellet boiler. Manufactured by Gerkros Heating in Co Tipperary, Ireland the woodpecker range of boilers are an affordable option for anyone wanting an alternative to oil/gas boilers. From http://www.dragon-stoves.co.uk/index.php?p0=detail&id=263&pageID=1.
5) KWB EASYFIRE / USP range. Fully automated boilers from 10 – 100kW. Standard features include automatic ignition, automatic boiler cleaning and automatic ash and soot extraction making the KWB essentially maintenance free between annual services. The Comfort 3.0 control system enables networked programmable control to up to 36 heating zones, 17 buffer stores and 17 hot water cylinders. From http://www.econergy.ltd.uk/KWB_USP.html .
6) Gilles HPK Wood Pellet Heating System. 10 – 145kW. Automatic ignition, de-ashing and heat exchanger cleaning. Cell wheel eliminates any risk of burn back. Suitable for smaller applications where access and storage are restricted. From http://energyinnovationsuk.com/gilles/pellet1.htm.
7) Multi Heat Wood Boiler. Uses various fuels – woodchips, pellets and grain/corn. Efficiency: 89-91%. Multifunctional digital control provides simple operation with continuously variable heat output from 30-100%. The boiler does not require a storage tank. There are grants available for this boiler – for more info go to www.lowcarbonbuildings.org.uk or www.eca.gov.uk. From http://www.fbcgroup.co.uk/baxi.html#MULTI%20HEAT .
8) OPOP COMFORT PELLETS BOILER. Models from 15 kw until 24 kw. Very Large inspection hatches, the boiler is easy to clean. Efficiency 93,3 %. From http://www.greenenergyltd.com/p_opop.asp. DOR PELLETS BOILER. Models from 15 kw until 45 kw. Efficiency 90,3 %. From http://www.greenenergyltd.com/p_dor.asp.
9) FROLING Pellet Boiler P2, 15kW or 25kW. Features: auto ignition, induced draft, auto cleaning of heat exchangers, low maintenance and cleaning requirements. From http://www.highlandwoodenergy.co.uk/pdf/Froeling%20P2%20Pellet%20Boler%20Brochure.pdf .
10) BioLyt wood pellet boiler. 10 – 26kW and 50kW. High efficiency wood pellet boilers supplied with fully automatic pellet feed, heat exchange cleaner and ash removal to integrated ash box. From http://www.hoval.co.uk/products/boilers/boiler17.htm.
11) JANFIRE Integral wood pellet domestic boiler package. Available in Scotland. From http://www.nuergy.com/equipment/?e=80 .
12) kofen Pelletmatic is an award-winning Austrian wood pellet boiler. 8kW – 32 kW. C omes complete with a choice of large scale pellet stores, with capacities suitable to hold a year’s supply of fuel, and a fully automated feed system direct to the boiler. From http://www.perthshirebiofuels.co.uk/boilers.html.
13) Windhager Biowin Wood Pellet boiler. Fully Automatic. 150 kg boiler storage hopper to Biowin with automatic suction pellet feed from bulk storage. From http://www.solarthermal.co.uk/biomass.htm. Also supply fuel.
There is a good list of suppliers and manufacturers of woodchip boilers at http://www.nef.org.uk/logpile/fuelsuppliers/woodboilers.asp?offset=0. There are also links for organisations doing research into using biomass as a fuel, etc. Although the EST website says that installing such a boiler could cost about 5,000, prices are normally higher.
Many woods in the UK have developed eco-systems that rely on trees being ‘managed’ – as they have been for centuries. So, as long as the wood comes from a sustainable source wood is considered a form of renewable energy.
Tags: boiler, off-the-grid, pellet stove, stove, wood burner, wood stove