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Emissions Characterization of Residential Wood-Fired Hydronic Heater Technologies
Citation:
Kinsey, J., A. Touati, T. Yelverton, J. Aurell, S. Cho, W. Linak, AND B. Gullett. Emissions Characterization of Residential Wood-Fired Hydronic Heater Technologies. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 63:234-239, (2012).
Impact/Purpose:
The data reported in this paper represents the first comprehensive comparison of the efficiency and emissions for different residential wood-fired hydronic heater technologies. As such the paper is an important contribution to the current state of knowledge for these appliances.
Description:
Residential wood-fired hydronic heaters (RWHHs) can negatively impact the local ambient air quality and thus are of major environmental concern in wood burning areas of the U. S. Few studies have been conducted which characterize the emissions from RWHHs. To address the lack of emissions data for these appliances, a study was conducted on four appliances of differing design using multiple fuel types to determine their thermal, boiler, and combustion efficiency as well as the emissions of carbon dioxide (CO2), carbon monoxide (CO), total hydrocarbons (THC), nitrous oxide (N2O), methane (CH4), total particulate matter (PM) mass, and particle number as well as particle size distribution (PSD). Three of these appliances were fired with split-log cordwood with the fourth unit using hardwood pellets. The measured thermal efficiencies for the appliances tested varied from 22 - 44% and the combustion efficiencies from 81 - 98%. Depending on appliance and fuel type, the emission factors ranged from about 1300 - 1800 g kg-1 dry fuel for CO2, 8 - 190 g kg-1 dry fuel for CO, and < 1 - 54 g kg-1 dry fuel for THC. For the particle phase pollutants, the PM mass emission factors ranged from 0.31 - 47 g kg-1 dry fuel and the PM number emission factors from 8.5 x 1010 to 2.4 x 1014 particles kg-1 dry fuel, also depending on the appliance and fuel tested. The PSD for all four appliances indicated the presence of a well established accumulation mode with two of the appliances also exhibiting a nucleation mode. The average median aerodynamic particle diameters observed for the four appliances ranged from 84 - 187 nm while burning red oak or pellets. In general, the pellet-burning appliance had the highest overall operating efficiency and lowest emissions of the four units tested.
