Mass flow and temperature measurements in the flue of a woodburning appliance

Abstract

The use of wood stoves for residential heating has been increasing over the past several years. This increased use of wood stoves has caused significant concern about increased air pollution. Development of improved emissions and efficiency measurement methods will allow the development of improved stoves.

Room calorimetry is used as the standard for measuring the energy efficiency of stoves. Unfortunately, this method is expensive and few wood stove manufacturers can afford it. For this reason, flue loss methods which are generally less expensive are attractive.

Flue loss methods measure either directly or indirectly the following instantaneous losses:

1. Sensible energy loss due to the flue gases being at a higher temperature than the ambient.

2. Chemical energy loss from incomplete combustion.

3. Latent energy loss due to water existing as a vapor in the flue gas. This loss is included since the higher heating value of wood is used.

The instantaneous efficiency of the stove can then be determined from measurement of these three losses and the instantaneous energy input.

This project is part of a larger project which has an overall objective to develop an accurate flue loss method. An accurate flue loss method is needed since many of the traditional flue loss methods have unknown accuracies.