Abstract
The aim of this work is the energy efficiency assessment of cogeneration systems based on biomass gasification for residential application, using a coupled multistage modeling approach. The gasification stage has been then modeled through an enhanced (i.e., gas-solid) thermodynamic approach using the Cantera solver and the Gri-Mech thermodynamic properties. Several values of temperature and amount of gasifying agent have been taken into account for the simulations. The efficiency of the whole CHP system has been evaluated supplementing the simulation of the gasification stage with the energy balance of the cogeneration set (i.e., internal combustion engine) and implementing the developed routines in the Matlab-Simulink environment. The CHP plant supplies thermal energy to residential buildings considering different plant size and operational times. Dynamic simulations by means of EnergyPlus 7.1 code have been performed concerning three main building configurations. The building-system interactions have been performed for the climate of Milan considering three different thermal resistances for the opaque building envelope. Domestic hot water consumption has been chosen in agreement with EN 15316-3-1:2007. The resulting building-system scenarios have been also compared with a conventional scenario of separated production by means of PES (primary energy saving). The paper shows the optimal operating conditions and the system size range for the chosen residential applications. The economical return of a such power plant has been mentioned. The gasification-based CHP technology represents a field of study of great interest, as it can have substantial room for improvement with respect to conventional separated generation systems at the same size.