Thermodynamic analysis of a renewable energy storage system based on a reversible organic Rankine heat pump cycle system

This research investigates a pumped thermal energy storage (PTES) system operating as a heat pump during charging and an organic Rankine cycle (ORC) during discharging, with analyses conducted in MATLAB using a particle swarm optimization algorithm. The study evaluates the system’s energy, exergy, performance for both pure and zeotropic working fluids. Results show that with pure fluids, the system achieves a power-to-power efficiency of ۰.۷۱۹۶, a heat pump coefficient of performance (COP) of ۶.۹۹۱۶, and an ORC first-law efficiency of ۰.۱۰۲۹, with the ORC turbine contributing ۲۱% to total exergy destruction. In zeotropic fluid mode, power-to-power efficiency increases to ۰.۷۷۹۹, COP to ۷.۰۵۴۵, and ORC first-law efficiency to ۰.۱۱۰۶, with turbine irreversibility rising to ۲۵%. A parametric study reveals that lower thermal storage temperature differences, higher isentropic efficiencies, and higher evaporator inlet temperatures enhance performance. Among zeotropic fluids, cyclohexane/pentane mixtures provide superior power-to-power and exergy efficiencies across most mass fractions.

کلیدواژه ها:

Energy storage ، waste heat recovery ، organic Rankine cycle ، heat pump cycle ، zeotropic working fluid