Co-publication with StableWood

ABSTRACT

Space-heating using wood stove is a popular solution in many European countries. Nevertheless, nominal powers of state-of-the-art stoves are oversized compared to the needs of highly-insulated building envelopes, such as passive houses. In this respect, a simplified wood stove model has been developed in order to investigate the thermal comfort using detailed dynamic simulations (e.g. TRNSYS) at an acceptable computational cost. A specific experimental setup has been developed to validate this modelling procedure, especially as regards the interaction between the stove and the building. The largest source of error appears to be the thermal stratification in the room where the stove is placed. This can simultaneously affect the conductive heat transfer between rooms, the thermal comfort sensation in the room as well as the convective heat exchange by flows through doorways. Nonetheless, the present work proposes a correction to circumvent this last effect. Finally, thermal comfort measurements during the experimental campaign confirm the conclusions of previous simulation results (Georges, Skreiberg, & Novakovic, 2014), supporting their proposed guidelines for the integration of wood stoves in passive houses.

Wood stoves are attractive for the space-heating (SH) of passive houses. Nevertheless, there are still questions about their integration. Firstly, the power oversizing of the current stoves and their long operating time may lead to unacceptable overheating. Secondly, it is also unclear how one stove can ensure the thermal comfort in the entire building. The paper investigates these aspects using detailed dynamic simulations (TRNSYS) applied to a detached house in Belgium. An 8 kW stove is assumed to be representative of the lowest available powers in the market. Results confirm that a large power modulation is important to prevent overheating. Opening the internal doors, a high building thermal mass and a heat emission dominated by radiation also reduce the overheating risk, but to a smaller extent. Besides, a single stove cannot enforce the thermal comfort during design weather conditions: a peak-load system is then needed. Using more standard conditions, a Typical Meteorological Year (TMY), the stove can mainly perform the SH but it then requires the internal doors inside the building to be opened. The temperature distribution between rooms is in fact dominated by the architectonic properties. Finally, the emission and distribution efficiency of the stove is also investigated.