The CHP (Combined Heat and Power) system MEGARIS (Micro Electric Generator from Alternative Renewable energy Innovative Stirling engine) is primarily a machine capable of producing electricity and thermal energy using renewable sources such as fuel (biomass) and solar energy. The biomass fuel could be used both as heat source integration to the solar or as alternative (for example during the night). MEGARIS is, conceptually, a system capable of self-sustaining and provide coverage for household energy for electricity, sanitary water and heating. This project is currently running (2011-2013). The Italian acting partners, AEROSOFT Spa (SME Leader), UNIVERSITA’ DEL SANNIO (RTD Performer), CNR - Istituto di Ricerche sulla Combustione (RTD Performer), have joined in a temporary association (ATS). The project is partly funded by the Italian Ministry of Environment and Protection of Land and Sea, MINISTERO DELL’AMBIENTE E DELLA TUTELA DEL TERRITORIO E DEL MARE, under the call for research projects aimed at energy efficiency measures and use of renewable energy sources in urban areas (G.U. n.297 del 22.12.2009).
MEGARIS main components are the solar concentrator, the Stirling cogenerator and the integrated FBC (Fluidized Bed Combustor) – solar receiver – heat exchanger and storage.
The CONCENTRATOR identified among the possible solutions for the capture and concentration of solar energy at low cost is a Scheffler adaptive type parabolic mirror, which performs solar tracking and maintains a fixed focus by means on a local deformation of the curvature. The concentrator focuses the sunbeams on the solar flux sensor / receiver, transferring the concentrated solar energy to the fluid bed and the heat exchanger of the Stirling. The Stirling engine cogenerator (R. Stirling, 1816) is based on an external combustion engine that is coupled to a dynamo or an alternator, providing electrical energy as well as part of thermal energy recovered in a heat transfer fluid.
The STIRLING engine also needs a cold exchanger, possibly at constant temperature (usually with cold water). The heat exchanger is integrated into the fluidized bed.
The FBC is a device in which combustion occurs in sand-like material suspended aerodynamically (fluidized) with an ascending column of gas. This technique allows high combustion efficiency of fuels with high moisture content, and is adaptable to various types of fuels such as "waste". The scrubbing action of the bed material on the fuel particles improves the combustion process by stripping away the ash layers that are normally formed around the fuel particle. This allows oxygen to reach the combustible material much more quickly and increases speed and efficiency of the combustion process.