Abstract
This manuscript investigates the thermal energy storage of nano-improved phase change material (NIPCM) used in a corrugated or undulated channel in heat exchangers. The problem is solved in two dimensions. The solution of the equations system is obtained by the Galerkin finite element method, and the enthalpy analysis is also performed. Flat, sinusoidal waves, square waves, triangular waves, and sawtooth wave profiles are considered different geometries of the plates. The impacts of Reynolds number (Re = 500–2000), inlet temperature (T = 65–80 °C), and nanoparticle volume fraction (φ = 0–8 %) on the thermal performance of heat exchangers are also investigated. The heat transfer fluid (HTF) between the plates is water, while the shell is filled with NIPCM (Cu-Paraffin). As the main outcome, the sinusoidal wave profile had the maximum average temperature and entropy, among other cases. Out of all the cases that were examined, the sawtooth plate had the best performance. At the highest values of Re, tin, and ϕ, the sawtooth plate reduced the melting time by 12 %, 11 % and 12 % compared to the flat plate, respectively.
•Thermal energy storage of nano-PCM is investigated.•Sinusoidal waves, square waves, triangular waves, and sawtooth wave profiles are considered.•The Galerkin finite element method (GFEM) is applied to solve the problem.•Entropy production was investigated and the best profile was selected.