Biomass boilers come in a range of sizes and designs, are fuelled by logs, woodchips or wood pellets, and can be installed for both domestic (small-large homes) and commercial purposes (biomass district heating systems, agricultural biomass grain dryer systems, etc).
A biomass boiler can be connected to an existing central heating and/or hot water system in much the same way as a standard gas or oil boiler.
Biomass heating systems are a great renewable energy solution for the direct replacement of aging oil, or LPG heating systems in areas not serviced by the mains gas grid, or to replace expensive electric immersion or storage heating systems.
Wood Chip Boilers
Wood chip boilers have dominated the commercial market in the UK. Fuelled by wood chips, these boilers can be configured to run on a wide range of different fuel specifications with moisture contents from 15% to 50%. Woodchip biomass boilers are available in a range of sizes from 40 kW (suitable for a large house or small business) to power station sized boilers of 100 MW and more.
Boiler responsiveness is determined by the fuel moisture content that the boiler is designed to accept; in general the drier the fuel, the more responsive and efficient the boiler. They can be fed automatically from a store of woodchips via an auger, making woodchip biomass boilers automated and simple to run.
Pellet Boilers and Stoves
Pellet boilers and pellet stoves range in size from a few kilowatts (kW) (for houses or small commercial buildings) – to megawatt (MW) size units (district heating systems).
Pellet systems are generally the most responsive of the biomass boilers, have the simplest controls and are the closest to fossil fueled boilers in terms of maintenance and operating intervention. The pellet fuel comes in a standardised size and moisture content, ensuring reliable and efficient heat generation.
Smaller systems are usually manually loaded but larger systems can be automatically fed.
Pellet burners are small burner units that can be attached or retrofitted to an existing log or oil boiler – converting it to burn wood pellets. A well designed pellet burner is very efficient and can achieve the highest efficiency level of class 5. Some pellet burners also feature modern extras such as lcd touch screen controls.
A pellet burner can allow a log biomass boiler to effectivly become a ‘dual fuel’ system that can burn both logs and pellets. It should be noted that while the pellet burner is fitted, the log boiler would only be able to burn wood pellets. To burn logs again, the pellet burner must be removed. It normally takes just a couple of minutes to add or remove a pellet burner.
Log boilers require wood logs to be manually loaded into the boiler, making them suitable for houses or small applications where labour is available. In contrast to a log stove, however, they are typically loaded just once or twice a day, and this batch of logs is then burned in one go, at high temperature and efficiency. This means that log biomass boilers are usually used along with a large water storage cylinder (a buffer tank, accumulator tank, or thermal store) to capture the heat produced, ready to be used when required.
The high efficiency of modern biomass log boilers means that there is very little ash leftover, reducing the frequency that the boiler needs to be emptied.
Traditional log stoves provide radiant heat to a room. They need to be manually fed with fuel as required to maintain the heat output, and achieve significantly higher efficiency (around 70%) than open fires. Some log stoves incorporate a boiler to provide hot water for domestic purposes or to heat radiators. Some may also incorporate a hob and/or oven for cooking. As mentioned, log stoves generate radiant heat into the room in which they stand and it is not possible to provide hot water without also heating this room.
Visit Our Showroom
The AC Gold renewable energy showroom in Stirling offers an opportunity to see a range of renewable energy systems on display including solar PV, off-grid power solutions and a range of domestic biomass log and pellet boilers.
11 Back O'Hill Industrial Estate, Stirling, FK8 1SH
Mon-Fri: 9am - 5pm