Performance Analysis and Working Fluid Optimization of a Cogenerative Organic Rankine Cycle Plant

The paper presents the results of a research regarding the application of cogeneration plants, based on organic rankine cycle (ORC), fed with wood residuals. In the first part of the paper an energy audit of the companies in a furniture industry district, located in the North-East of Italy, is presented. On the basis of these data a typical electricity/thermal demand profile dependent on the number of employees has been determined. In order to evaluate the potential savings achievable with an ORC cogeneration plant, a numerical simulation model has been developed to analyse the energy balances of the components as well as the whole ORC power plant performance. The effects on the system energy and exergy efficiencies of different binary and ternary mixtures of polisiloxane as working fluid and of different operating modes (cogeneration or pure electricity production) have been analysed, also in off-design conditions.