Simplified dynamic model for heat input and output of heat storing stoves

Abstract

A simplified method to describe the dynamical heat output from heat storing stoves for small houses with a single or several successive firing batches is presented. Both measurements in a stove and theoretical and experimental studies of the combustion of single wood logs can be applied to study the heat input from the batch firing to the furnace walls. Different distributions for presenting heat input as function of time from the firing of a batch are discussed. Three different approaches can be made. The first is to present the measured heat input by fitting a statistical distribution such as lognormal or gamma distribution. The second approach is to apply a distribution that is based on the approximate combustion physics of a wood log. These two types of input distributions can be applied as a boundary condition for numerical simulation of heat output of different stove constructions. The third alternative is to select input distribution function, which is so simple that analytical solution for the heat output calculations of an idealized stove for approximate and fast simulation is possible.