Modeling and Evaluating a New Solar-Geothermal Trigeneration with Nanofluid from Exergy and Environmental Impact Concepts

This research deals with a new solar-geothermal driven trigeneration system based on organic working fluid, namely R423A and R1234yf. In the solar subsystem, copper oxide CuO/water nanofluid is applied as heat transfer fluid inside the flat plat solar collectors. The proposed system is modeled from the exergy and exergoenvironmental concepts. Sensitivity analysis is carried out for exergetic and environmental criteria. The major parameters are selected as the decision variables of the desired system. Results of modeling show that R1234yf with high exergetic and low environmental impact is the convenient working fluid in trigeneration. Sensitivity analysis outcomes indicate that the increment of nanoparticles, area ratio of ejector and pressure drop of ejector have a positive effect while the increment of turbine inlet mass flow rate, turbine inlet pressure and turbine outlet temperature have a negative effect on both exergetic and environmental criteria of system.