Efficiency and economical assessment of a solar powered dryer combined with a biomass gasification system

This work follows the study presented in Matera at the 4th AIGE/IIETA International Conference titled: “Analysis of energy saving potential of combined thermal solar power and micro scale gasification systems”. This previous work was focused on the advantages gained through the integration between thermal solar power and a small scale gasification system and how to maximize them. The results showed that the best way to combine the two systems is to use to heat generated with the thermal solar power to dry the fuel rather than heat up the gasification air. In this second work the best scenario will be analyzed considering the annual irradiance in the Province of Modena in northern Italy. The systems considered in this study were the APL PP30, a biomass gasifier genset system able to produce 22 kWel at 50 Hz, and the Chromasun Micro-Concentrator (MCT), a high performance solar collector able of 2.2 kWt output peak at DNI of 1000 W m-2. Results showed that four thermal solar units are sufficient to dry the biomass consumed in a year by the gasifier, increasing substantially its efficiency. The economic feasibility of this scenario was investigated considering a possible substitution of the methane as the heat source of the biomass dryer. Considering a discount rate of 5 % and an inflation rate of 2.5 % it is possible to have a positive NPV after 22 years from the purchase of the 4 thermal solar units. Furthermore, it is possible to save 2286 kg of CO2 using solar energy rather than methane every year.