This is becoming a more common feature of sweeping in the Walden area, the cleaning of biomass boiler flues. In the past couple of months I have swept three of these Okofen biomass boiler systems. These were all providing heating and hot water to domestic dwellings in the local area; Debden where the photograph was taken, Henham and Rickling Green. This make of biomass boiler is fueled by burning specially made wood pellets; they are a small pellet of compressed wood shavings. Apparently they are designed in such a way to optimize the burn and efficiency of the biomass boiler. The pellets are stored in an adjoining hopper and are automatically fed into the boiler as it demands additional fuel. The boilers burn so efficiently that the produce only a very small amount of extremely fine soot that again is automatically fed from the fire box into a waste hopper. The owner need do very little other than occasionally top up the pellet hopper and then sit back and enjoy the benefits of cheap heating and hot water.
Okofen are an Austrian company and one of the world leaders in producing pellet fed biomass boilers, indeed they produced the world’s first pellet fed boiler in 1997.