ALMOST ZERO EMISSION WOOD STOVES

The primary objective of the current project was to develop ultra-low emission, low to medium heat output wood stoves in line with tomorrows stringent emission limits as well as space heating requirements of low-energy and passive houses. Three routes with specific technologies, which could solve these problems, which could solve these problems were proposed in the current project. The specific woodstoves developed and commercialized during the AZEWS project are listed below each of the three objectives associated with each of the participating project partners. Objective 1. Stove with downsized combustion chamber, operated in quasi-gasification mode with semi-automatic feeding, able to operate at ultra-low emissions with weighted particle emissions of down to 2 g/kg, with a minimum net effect to the room of 1.5 kW and upwards and batch periods of up to 2.5-4 hours. Results: 1. Dovre ZEN, 4.78 g/kg, 2 KW, 80.1% 2. Dovre SENSE, 2.87 g/kg, 3.3 KW, 79.5% 3. Dovre BOLD, 1.5 g/kg, 2.3 KW, 80% 4. Dovre ROCK, 1.4 g/kg, 2.3 KW, 80% 5. Dovre TAI, 3.58 g/kg, 3.9 KW, 81% Objective 2. Stove with heat storage capabilities, able to operate at ultra-low emissions with weighted particle emissions of down to 1 g/kg operating at a minimum net effect to the rom of 1.5 kW and upwards. Results: 6. Jøtul F 305 LL, 0.8 g/kg, 3.7 kW, 79% 7. Jøtul F 105 B, 0.8 g/kg, 2.4 kW, 83% 8. Jøtul F 373 Advance, 0.6 g/kg, 3.0 KW, 78% 9. Jøtul F 163, 1.24 g/kg, 3.0 KW, 82% Objective 3. Light heat storage soapstone stove, able to operate at ultra-low emissions with weighted particle emissions of down to 2 g/kg operating at a minimum net effect to the rom of 1.5 kW and up-wards. Results: 10. Norsk Kleber Marcello, 1.24 g/kg, 2 kW (estimated average power to the room), 82% 11. Norsk Kleber Domino, 2.5 g/kg, 2 KW (estimated average power to the room), 79% All-in-all, during the time span of the project 11 different wood stove models were developed and commercialized, either directly or indirectly related to project activities. As seen from the performance listing above, all models are able to operate in the vicinity of 80% in terms of efficiency. Some of the models are extraordinary when it comes to emissions of particulate matter as well as efficiency. Com-pared to the goals set at the initiation of the project, none of the resulting stoves have net effects as low as 1.5 kW, the reason being not the ability to achieve this but rather little current demand in the market. The flame picture of a wood stove operating at 1.5 kW is rather unsatisfying and might explain why the manufacturers hesitates to release products with such low heat outputs, since the visual impression of the flame picture is one important purchase argument such. As for the semi-automatic feeding system, none of the resulting stoves had such a system implemented. However, prototypes do exists with such systems. These will be continued to be developed in the new IPN project TheONE (The Universal Wood Stove Combustion Chamber, ref. 269372).

Due to the several recent challenges related to more stringent emission limits and testing standards in combination with increasingly airtight dwellings and associated problems of internal smoke leakage, all producers of wood stoves need to take imminent action within the next few years to develop closed wood stoves that can cope with both significantly reduced emissions and heat release. The current project proposal comprise a joint cooperation between the three Norwegian wood stove producers DOVRE AS, J ØTUL ASA and GRANIT KLEBER AS with SINTEF Energy Research as research partner. The new technological solutions proposed in this project are based on knowledge gained in several finished an on-going projects led by SINTEF. In addition to concepts developed through several previous user-directed innovation projects, generic knowledge from both the FME CENBIO and StableWood projects can be implemented to provide valuable solutions. CENBIO has generated valuable knowledge related to particle measurements, emi ssions and analyses, in addition to first-hand expertise gained through continuous monitoring of on-going standardization and regulation initiatives like CEN/TC295 (Central European standard/Technical committee 295) and LOT20 (local space heaters product group) Ecodesign workgroups. StableWood has generated knowledge regarding new heat storage materials like phase change materials. The main goal for each of the individual industry partners is to translate this knowledge into specific prototypes with the a im of finalizing these into market ready products by the end of this project. The successful outcome of this project will enable stove technology that is ready to cope with tomorrows strict emission limits and increased efficiency requirements without com promising the heat comfort in low-energy and passive houses. This is in line with the national strategy of increased biomass for energy production.