At present, wood as an energy source accounts for around 4 % of final energy consumption in Switzerland. One objective of Energy Strategy 2050 is to increase this share to more than 7 % by, for example, heating residential buildings with wood chips rather than oil. During the burning of wood, however, pollutants such as particulate matter and nitrogen oxides are released into the air. The researchers of the Lucerne University of Applied Sciences and Arts investigated how emissions that are detrimental to health can be minimised.
To this end, they examined nine different types of combustion system, including both automatic and manual variants. In doing so, the scientists varied the operating conditions and the fuels used, allowing them to measure a total of 51 combinations. In addition to normal operations, the different operating conditions included cold and warm starts as well as operations with a lack of air. The fuels included wood pellets, wood chips as well as dry and damp pieces of beech.