Challenge of energy will be increase in whole world by augmenting relevance of industry with fossil energy. According to this fact, renewable energies become popular in recent years. Employing nanofluids can help scientists to improve the performance of such systems. The impact of iron oxide–water nanofluid, as working fluid, was employed to evaluate entropy generation in an enclosure in existence of magnetic force. To analyze the performance of heating unit, both view of first and second law of thermodynamic should be involved. In current research, environment-friendly magnetic fluid namely Fe3O4-water ferrofluid has been studied which is useful in magnetic nanostructured materials have been found to be very efficient in wastewater decontamination. More exactly, the behavior of magnetic nanofluid through a porous space with innovative computational method is displayed. To involving porous media, non-Darcy approach was considered. Outcomes are obtained via Control volume based finite element method (CVFEM) to portray the impacts of Hartmann, Rayleigh numbers and permeability. Results display that dispersing nanoparticles leads to augment in thermal performance and decrease in entropy generation. As permeability enhances, Bejan number improves. As Lorentz forces augments, impact of adding nanoparticles reduces and exergy loss detracts. Dispersing nanoparticles are more beneficial in lower values of permeability.