f. a. boyaghchi

This study deals with a cascade organic Rankine cycle driven by linear Fresnel solar collector as a source and cold energy of LNG to produce power. An exergy concept is used to model the system and the performance of the desired system is assessed by varying the major design parameters namely solar subsystem feed mass flow rate, LNG mass flow rate and turbines inlet and back pressures. A Parametric study shows that among the design parameters solar subsystem feed mass flow rate and turbine 1 back pressure have positive effects on the performance of the system and maximum efficiencies increments are achieved within 5.24% as turbine 1 back pressure increases.

A theoretical investigation is conducted for a novel renewable energy based multigeneration system producing hydrogen by means of a proton exchange membrane (PEM) electrolyzer as well as several commodities, namely power, drying, cooling and hot water. Engineering Equation Solver (EES) software is applied to model the PEM electrolyzer and multigeneration system. Thermodynamic, cost and environmental impact evaluations are included for hydrogen produced by considering the major design parameters. Outcomes indicate that the turbine inlet press. increases the hydrogen exergy efficiency of the system within 56% and decreases its environmental impact by about 3.8 % whereas it has a negative effect on the hydrogen cost produced. Moreover, the current density and temperat. of the electrolyzer affect the cost and environmental impact of hydrogen negatively.