MICROCOGENERAZIONE SOLARE AD ALTA EFFICIENZA E PICCOLA SCALA ENERGETICA

This experimental work is focused on a small solar cogeneration system of about 1 kW of electric power and up to 3 kW of thermal power, designed for the decentralised and diffuse production of heat and power with high conversion efficiencies at low power scale. The presented solar system makes use as microcogenerator of an industrial Stirling engine of small size, with an electrical efficiency up to 32%, originally designed for domestic combined heat-power applications in gas boilers. The heat acceptor of the Stirling head has been completely re-engineered for the solar application, together with a solar dish concentrator moved by a suitable two axis tracking system. In one year the average electricity produced is about 185 kWh/m2 and the average thermal energy is around 858 kWh/m2. The resulting annual electrical efficiency is about 9%, but can be improved, and the annual thermal efficiency is about 46%. The collecting surface of the solar dish measures approximately 9.6 m2, about the 50% of the collecting surface for an equivalent non-cogenerative syste