Heat accumulation in solid materials during the combustion of solid fuels

Abstract This study focuses on the experimental evaluation of the effect of heat accumulation on the course of heat output of wood-burning stoves using wood logs. The motivation comes from the unstable nature of batch combustion, which leads to significant fluctuations in heat supply and a related decrease in thermal comfort. The measurements were carried out by using a calorimetric chamber under three operating conditions – without heat storage and with heat storage elements around the flue gas path under different combustion air supply modes. The results show that heat accumulation in the presented setup reduces the instantaneous heat output by approximately 15% during operation. At the same time, it helps to smooth the heat output over time and extends the post-combustion heat-release phase. The accumulation of sensible heat therefore appears to be an effective way to stabilize the operation of local biomass heaters, making it suitable, for example, for buildings with low heat demand.