Performance Evaluation of a Modern Wood Stove Using Charcoal

Abstract

Modern wood stoves can achieve high efficiency and relatively low levels of harmful emissions. However, controlling wood logs’ combustion remains challenging, and the emission levels of unburnt compounds are generally higher than for e.g. wood pellet stoves. One solution is to upgrade the fuel quality, enabling a more stable combustion process. Thermal upgrading of wood through carbonization yields the highest achievable quality of solid fuel from wood. In this work, two types of charcoal were tested in a commercially available wood stove at various loads, with and without a retrofitted custom-design catalytic converter. The test procedure was adapted from the Norwegian test standard NS 3058 for higher repeatability and comparison with existing data. Emission levels were continuously measured using both a conventional- and a FTIR gas analyser. Particle emissions were measured both using a dilution tunnel with a total filter and an Electric Low Pressure Impactor (ELPI).The test results show that for the selected stove, without any modifications, the emission performance for most of the measured compounds was in a similar range to wood logs. CO emissions were significantly higher, though with the addition of a catalytic converter, measured CO emissions could be cut by 74-83% on average. The test campaign demonstrates that combustion stability improvement and reduced heat output throughout a longer combustion time can be achieved by using charcoal in a wood stove, but highlights the need for both design and operational changes to reach commercial solutions.