Modelling of a CHP SOFC power system fed with biogas from anaerobic digestion of municipal wastes integrated with a solar collector and storage units

The paradigm of the sustainable energy community is recognized as the future energy approach due to its economical, technical and environmental benefits. Future systems should integrate renewable energy systems applying a "community-scale" approach to maximize energy performances, while minimizing environmental impacts. Efforts have to be directed toward the promotion of integrated technical systems needed to expand the use of renewable energy resources, to build sustainable local and national energy networks, to guarantee distribution systems for urban facilities and to reduce pollution. In this framework poly-generation is a promising design perspective, for building and district scale applications, in particular where different types of energy demand are simultaneously present and when sufficient energy intensity justifies investments in smart grids and district heating networks. In situ anaerobic digestion of biomass and organic waste has the potential to provide sustainable distributed generation of electric power together with a viable solution for the disposal of municipal solid wastes. A thermal recovery system can provide the heat required for district-heating. The system analysed is a waste-to-energy combined heat and power (CHP) generation plant that perfectly fits in the sustainable energy community paradigm. The power system is divided in the following sections: a) a mesophilic-single phase anaerobic digestion of Organic Fraction of Municipal Solid Waste for biogas production; b) a fuel treatment section with desulphurizer and pre-reformer units; c) a Solid Oxide Fuel Cell (SOFC) for CHP production; d) a solar collector integrated system(integrated storage system-ISS). An integrated TRNSYS/ASPEN Plus model for simulating the power system behaviour during a typical reference period (day or year) was developed and presented. The proposed ISS consists of a solar collector integrated with storage systems system designed to continuously provide the thermal power required by the anaerobic digester. The net thermal energy production as a function of reactor volume, thermal insulation and additional preheating is evaluated