Reduction of Emissions Through Electro-Thermal Post-Combustion in Singel Room Stoves

This study, part of Project E-TNV (Electro-Thermal Post-Combustion), investigates the reduction of emissions from wood-burning small-scale heating systems, which significantly contribute to Germany’s particulate matter emissions. With over 10 million such systems and substantial emissions reported in recent years, this research focuses on two primary methods for reducing CO emissions: altering wood log geometry and implementing post-combustion using an electric heating wire in a 6 kW single-room natural draft fireplace. Initial tests revealed that high draft velocities and low wood moisture increased emissions, which were mitigated by shortening wood logs from 17 cm to 15 cm to enhance combustion time and installing an external air valve to manage airflow. Results showed that the combination of both methods achieved a CO reduction of up to 50 % at nominal load, compared to 35 % reduction with wood geometry optimization alone. The study also explored the efficiency of different voltages (180 V, 200 V, 220 V), which correlates to different power outputs (1.2 kW, 1.5 kW, and 1.8 kW) respectively, for the heating wire, finding that 220 V offered an 18 % better reduction than 180 V. It was determined that using the heating wire only at the start and end of combustion could reduce operational costs by approximately 50 %. The study highlights the potential of these methods for emission reduction, while also suggesting practical challenges like the need for precise wood preparation and proposing quality of life methods such as automated oxygen regulation via sensors for real-time air control.