Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.
The author recently published the first combustion efficiency charts for the combustion of biofuels, namely biodiesel and yellow grease. The charts give values of efficiency down to a stack temperature of 250 F. At this temperature no condensation of water vapour in the flue gas occurs. Condensing boilers, water heaters, and hot air furnaces are increasingly being utilized. In order to easily measure the performance of these devices or to do analysis of the effect of various changes (particularly important is the effect of stack oxygen content) one must utilize combustion efficiency charts for condensing equipment. This paper describes the development of charts for this application and gives charts for two important biofuels: biodiesel and yellow grease. Since these charts are the first publication of results of this type, the paper represents an important milestone in two areas that are evolving in mankind’s quest to secure a renewable energy supply and to reduce harmful emissions by operating equipment on biofuels at maximum efficiency (i.e. utilizing latent heat in stack gases through condensation).