Análise exergética de uma planta de cogeração híbrida solar/biomassa

Abstract

The discussion on the use of renewable sources for energy generation has become increasingly recurrent, including an idea of using two renewable sources together, that is, hybrid plants. Developing this project is a complex task, as is not used one, but two sources of energy to maintain the constant supply of electricity. This work makes an exergetic analysis for three configurations of solar fields integrated to a thermoelectric plant, verifying the work potential of each component in the process. The plant uses wood residues as fuel and, together with the Fresnel technology of concentrated solar energy (CSP), generates a power of 28 MW, and is studied as a possibility of being implemented in the Brazilian Northeastern semi-arid region, in the city of Guanambi (BA). The yearlong simulation resulted in a biomass saving of 1,9% to 9,7% and in a drop in exergetic efficiency of 16% in the configuration with the greatest solar contribution. The drop in exergetic efficiency is proportionally linked to the entry of solar energy. While an analysis of the first law suggests that the lowest temperature solar field is the most efficient and the one to be invested, an analysis of the second law based on the exergy suggests the opposite, recommending the highest temperature field due to its lower destruction of exergy.