Mass Flow and Temperature Measurements in the Flue of a Woodburning Appliance

摘要

This study investigates several possible errors in flue loss methods used to measure the efficiency of woodstoves. Possible errors from using an unshielded thermocouple in the centerline of the stack for measuring the sensible energy loss were investigated. A wet-basis CO tracer, a pitot array, and a scaled-based technique were used to simultaneously measure the flue gas flow rate. A wet-basis CO tracer measurement technique for measuring flow rates in wood stove flues is described. The results of this study imply that appliances with high sensible energy losses (around 50% of the total input energy) should use a fine-gage thermocouple array to measure the stack temperature. Agreement within 10% was usually observed between the pitot array and the Co tracer. For unknown reasons, poor agreement (i.e., flows differ by 15% or more) was observed between these two methods following an abrupt change in the flow conditions. The scalebased method was hampered by noisy scale readings which prevented an accurate burn rate measurement. (ERA citation 12:011517)