Thermodynamic Investigation On Different ORC Configurations

The organic Rankine cycle (ORC) is an emerging technology for power generation by recovering heat from different thermal sources. The most common applications are biomass power plants, recovery of wasted heat from industrial process and engine flue gases; applications under investigation are also geothermal, solar desalinization, biogas applications and heat recovery from waste-to-energy power plants. The ORC adopts a simple thermodynamic concept and is based on the use of particular organic fluids as working medium and their characteristics have a strong influence on the cycle performance. The general aim of the study started on the ORC at the University of Bologna is to perform different thermodynamic investigations on the potentiality of this kind of energy system, considering specific applications. The starting point for the analysis described with this paper/poster is the study of subcritical cycles, by considering fourteen fluids as working medium, including aromatics, linear siloxanes, refrigerants and hydrocarbons. This paper/poster represents a preliminary numerical study to assess the relevance of the main cycle parameters and to calculate the performance in term of heat recovery efficiency. To improve the recovery efficiency and the net power output of the ORC different cycle modifications are evaluated, such as superheated cycle, supercritical conditions and other cycle modifications. A parametric analysis of these cycles has been carried out at different evaporation pressure values, to identify the best operating condition. Preliminary results of the investigation will be provided.