Thermal storage unit can be utilized to satisfy the balance of energy supply and demand. Copper oxide nanoparticles and V shaped fins are involved in storage unit in current research to expedite the solidification. To show the variation of energy storage efficiency, Finite element method has been employed. Important selected parameters are nanofluid concentration, angle of V shaped fin, copper oxide particle size and length of fins. Contours and profiles in various time steps are depicted. Outputs display that discharging rate augments with rise of angle of V shaped fin. Using copper oxide helps solidification. Length of fin has inverse relationship with discharging rate. (C) 2018 Elsevier Ltd. All rights reserved.