Selection of the working fluid for a high-temperature ORC hot-source to be applied in the Brazilian semi-arid

Abstract

This paper aims to select the most suitable working fluid to be applied in a high temperature regenerative hot-source ORC, such as those driven by biomass, for climatic conditions measured from real data in Bom Jesus da Lapa in northeastern Brazil. To this end, the most commonly used working fluids in these systems were selected among numerous authors, discarding those with high GWP and ozone depletion potential and those classified as wet according to the slope of their temperature-entropy diagram. Then, from the model developed in the software EES, the simulation and performance analysis of the proposed system was performed based on thermal efficiency. It was conducted a fluid selection from the adaptation and expanding the parameters of the qualitative spinal point method, considering the thermodynamic performance, environmental preservation criteria, safety, and fluid characteristics. As a result, it was obtained that hydrocarbons present the best thermodynamic and qualitative performances, with benzene and cyclohexane being the most attractive to be used as fluids in the proposed Rankine cycle, followed by n-hexane.