The aim of this work is to investigate the effect of a laminar pulsating heat transfer fluid (HTF) flow on the melting of nanoparticle-enhanced phase change material (NEPCM) inside a shell-and-tube latent heat storage unit (LHSU). The shell space is filled with n-octadecane as a base phase change material (PCM) dispersed with copper nanoparticles. A heat transfer fluid (HTF: water) flows in the inner tube and transfers heat to NEPCM. A mathematical model based on the energy conservation equations has been developed and validated by experimental, numerical and theoretical results. Numerical simulations were conducted to investigate the effect of the volumetric fraction of nanoparticles on the thermal behavior and performance of the storage unit.