Thermo-economic analysis of the combined solar based pre-compression supercritical CO2 cycle and organic Rankine cycle using ultra low GWP fluids

Present study deals with the parametric and economic analysis of solar driven combined pre-compression supercritical CO2 cycle and organic Rankine cycle using ultra low global warming potential HFO (hydro fluoro olefins) fluids and comparison with the R134a fluid. A numerical model was developed with the help of EES software to simulate the combined system. It was concluded from the results that HFO working performed better than the R134a. R1336mzz(Z) gave highest thermal and exergy efficiency and power output for the combined cycle by 55.02, 59.60%, 298.5 kW at 950 W/m2 of solar irradiation respectively. Also highest waste heat recovery ratio was found 0.84 for the R1336mzz(Z) fluid while R134a gave only 0.099 at 0.95 heat exchanger effectiveness. At end, it was found that the R1336mzz(Z) and R1234ze(Z) estimated the lowest and highest specific investment cost i.e. 2234 and 2290 & euro;/kWe respectively. It was also concluded from the results that if the fluid is the best for thermal performance, it is not necessary it would be best from the economic point of view.