Monthly assessments of exergetic, economic and environmental criteria optimization of a solar micro-CCHP based on DORC

This research performs an analytical simulation of a novel solar-driven combined cooling, heating and power (CCHP) system based on a dual organic Rankine cycle (DORC) using heat transport fluids of water and Copper (II) oxide (CuO)/water nanofluid. The major design parameters are encompassed to evaluate the monthly thermodynamic efficiencies, total product cost and environmental impact (EI) rates of the system for four selected organic fluid groups, namely R134a-R245fa, R1234yf-R245fa, R1234ze-R236fa and R423A-R236fa. According to results, a considerable positive influence is observed in the energy and exergy efficiencies within 16.71% and 24.34%, respectively for R1234yf-R245fa in November. The lowest EI rate is achieved by 1.2% for R1234ze-R236fa in April as turbine 1 inlet pressure increases and the highest decrement in El rate is calculated within 2.48% for R1234yf-R245fa in September with an increase in turbine 2 back pressure. In addition, two well-known decision making techniques comprising LINAMP and TOPSIS are applied to identify the ultimate optimal performance of the system among the solutions gained from the non-dominated sorting genetic algorithm (NSGA-II) approach. Referring to the optimization results, the maximum improvement in the exergy efficiency and product cost can be obtained within 33.49% through the LINMAP method and 23.67% through the TOPSIS procedure, respectively and the highest improvement in the El rate is calculated by about 22.7% with 0.01788 nanoparticle volume fraction for R134a-R245fa through the LINMAP method.