Evaluation of a new system combining wood-burning stove, flue gas heat exchanger and mechanical ventilation with heat recovery in highly-insulated houses

Abstract

The performance of an innovative flue gas heat exchanger (FGHE) located at the exit of a wood-burning stove (log or pellet) to pre-heat ventilation air has been assessed for highly insulated detached houses. For this purpose, transient thermal simulations (TRNSYS + TRNFlow) were carried out on a Norwegian house typology (passive house standard NS3700) and a French house typology (building regulation RT2012) – both equipped with mechanical ventilation systems with heat recovery (MVHR). Seven different climates were considered ranging from mixed (Nice, France) to subarctic conditions (Karasjok, Norway) in order to evaluate the impact of the system in terms of energy use for space-heating and thermal comfort for a broad range of operating conditions. The tested system allowed an improvement of the thermal comfort in the bedrooms furthest away from the stove: up to 7.6 °C of the 5th percentile of the operative temperature (Top 5%) for France and up to 9.5 °C for Norway, compared to the houses without the system. Furthermore, energy savings of up to 19% over the space-heating season were reported, depending on the type of wood-burning stove (i.e. log or pellet) and control used during operation.