Modeling and improvement of solid oxide fuel cell-single effect absorption chiller hybrid system by using nanofluids as heat transporters

In this study, a solid oxide fuel cell (SOFC)-single effect absorption chiller hybrid system was modeled in order to improve the energy efficiency and to investigate the effect of using nanofluid as the fluid circulating through the pipes and radiators of the building to exchange heat between the evaporator of chiller and the building. Six nanofluids containing copper, silver, copper oxide, and alumina nanoparticles and single and multi-wall carbon nanotubes were used and the influence of each one individually, on the thermal performance of the system was investigated. For example, multi-wall carbon nanotubes-based nanofluids would improve the coefficient of performance of the absorption chiller by up to 27% and the thermal efficiency of the hybrid system from 0.82 to 0.886. By increasing the concentration of nanoparticles, the viscosity will be increased, it causes increasing friction factor and pressure drop in nanofluids. The threshold concentrations were 2.0% for copper oxide and alumina nanoparticles and 0.1% for copper and silver nanoparticles and both nanotubes. Also, the effects of using nanofluids on the coefficient of performance, cooling load, overall heat transfer coefficient, hybrid thermal efficiency, cooling water outlet temperature and the flow rate of water were investigated.