Techno-economic analysis of a renewable quadruple hybrid system for efficient water/biofuel production

This study aimed to design and construct a quadruple solar/hydro/biomass/geothermal hybrid system, using a techno-economic analysis for water/biofuel production as energy carriers. First, in the case of the ground source heat pump-assisted microalgal culture pond, three influencing factors including light intensity, salinity, and air injection were investigated for maximum biomass production. Then, in the parabolic trough collector, the flow rate of operating fluid, the used hybrid nanoparticles, and their ratios were considered for obtaining the highest thermal efficiency. After, providing a better solar still distiller for the highest water production efficiency, the pressure, fluid's flow rate, and the depth of solar still were investigated. Finally, the water/heart supply of producing biodiesel from the pond's biomass in the trans-esterified conversion reactor was provided from the distiller/collector. The results indicated that using a 300-lx light intensity, a 3-g/L salinity, and a 0.4-L/min air injection in the pond, a 3-L/min nanofluid, including CuO/GO (4:1) and mass fraction of 0.4 in the operating fluid in the collector, a 2.5-cm water depth under a 0.4-bar pressure in the distiller, and a 1.8-wt%/wt catalyst concentration under a reaction temperature of 55 degrees C at 50 min in the reactor would yield the best water/biofuel production efficiency of 55%/80%.