Thermal optimization of a novel solar/hydro/biomass hybrid renewable system for production of low-cost, high-yield, and environmental-friendly biodiesel

Abstract This study tried to optimize the solar collector working fluid by hybrid nanoparticles in order to increase efficiency and decrease costs of biodiesel production following the fabrication of the parabolic trough solar collector and formation of the hybrid system of solar collector/desalination/conversion reactor by deploying biomass conversion reactor along with the solar collector. Therefore, after designing the experiment based on the nanoparticle concentration in the fluid, the hybrid nanoparticles weight ratio and the collector fluid flow rate, the nanofluid containing carbon nanotube and MgO (with 25:75 wt ratio) and nanoparticle mass percentage of 0.336 in the base fluid with flow rate of 2.5 L/min were selected as the optimum nanofluid. Under optimum condition, the operating cost of the collector improvement was $169 and 81 cents per year, and its thermal efficiency was 56.59%. Then, we used transesterification and produced biodiesel by heating the parabolic solar collector and using palm/rapeseed biomasses and chlorella microalgae at 60 °C. The conversion percentage of biomass into biodiesel for each of the palm, rapeseed and, chlorella species were 76.31, 74.54, and 81.4, respectively. Moreover, the cost of biomass conversion into biodiesel for palm, rapeseed, and chlorella species was $0.73, $0.54, and $1.27, respectively.