Abstract
Low load wood stoves in new highly-insulated buildings demand new technologies and solutions with an increased focus on the combustion process and its control, the combustion quality and optimum design to ensure low emissions and high energy efficiency. The goal is to maintain or even further reduce the particle emission levels achieved for the larger units, while at the same time achieving a high energetic performance. The objective of this work is to 1) review the environmental and energetic performance history for wood stoves, with special focus on the last two decades, and 2) evaluate the further improvement potential for wood stoves.
The introduction of the Norwegian wood stove testing standard, NS 3058/3059, in 1998 introduced an emission limit for particles of 10 g/kg dry wood for new wood stoves. From this moment in time the staged combustion air units, with both primary and secondary air addition, have completely dominated the wood stove market. These wood stoves also have the potential to perform energetically much better than old types of wood stoves, due to better combustion air control, reducing the overall excess air ratio.
During the last two decades, continuous improvements have resulted in wood stoves with much reduced particle emission levels, down to more than 80% particle reduction compared to the 10 g/kg dry fuel emission limit, in commercial wood stoves. However, there is still a significant further improvement potential.
