Performance comparison of different thermal fluids in concentrating solar plants

Concentrating Solar Plants (CSP) represent a feasible alternative to fossil fuel driven power plants. Anyway, technical and economic issues severely prevent their large diffusion over the world. In this paper, a numerical investigation is accomplished to predict the performance of a CSP without thermal storage (TES). A stationary, 1-D model of heat transfer fluid (HTF) is presented, taking into account the heat losses occurring along the Heat Collector Element (HCE). A Southern Italy location is considered for the solar plant simulation, and two HTF thermal oils, Therminol VP1 and Therminol 62, are compared in terms of thermal power delivered to the power plant block. HTF temperature distribution and velocity profile along the solar plant are obtained to evaluate the performance of a coupled Organic Rankine Cycle (ORC) plant, simulated using the DWSIM programme, emphasizing the differences when using three different types of working fluids, i.e. wet, dry and isentropic.