DECOG - A dual fuel engine micro-cogeneration model: Development and calibration

The use of gaseous fuels in compression ignition (CI) engines for cogeneration allows diesel substitution and particulate matter reduction, however, power efficiency is reduced while CO and THC emissions are increased at part-load conditions. The development of micro-cogeneration systems based on dual fuel engines requires the actual heat recovery estimation, which in turn depends on the power efficiency in all operating range. In this paper, the development of a dual-fuel engine cogeneration model (DECOG) based on International Energy Agency-Annex 42 methodology is presented. This model considers the effect of substitution level on micro-cogeneration efficiencies, capturing these effects on model correlations. Through an experimental study, the steady-state performance of the unit is presented and analyzed and compared with original correlations of Annex 42 model. The effect of overall thermal conductance variations with the load and substitution level are analyzed. Good agreement was found between the model proposed and the data collected to calibrate it, with cumulative errors below 4% for system efficiencies, pilot fuel flow rate, and air flow rate. An improvement near to 90% on the agreement between experimental and predicted efficiencies was found using the correlations of the model proposed respect to IEA-Annex 42 model correlations.