Variation of the cumulative heat stored in n-hexadecane (C16), n-heptadecane (C18) and n-eicosane (C20) as function of temperature. Display omitted •Thermal properties of n-hexadecane, n-octadecane and n-eicosane used as PCM are reported.•Thermal conductivity and thermal diffusivity were measured by the hot wire technique at different temperatures.•A discontinuity in thermal conductivity and diffusivity was detected near the melting temperature.•No literature data were found for the thermal diffusivity of the three n-alkanes considered in this study.•The cumulative heat stored increases with the number of carbon in the n-alkane hydrocarbon chain. The thermal conductivity (λ) and thermal diffusivity (aT) of the solid/liquid phase change linear n-alkanes were measured simultaneously by the transient multi-current hot wire technique at atmospheric pressure in the range 258–348K. The same set-up was used to measure λ and aT of the liquid and the solid states at different electrical currents. Three n-alkanes, n-hexadecane (C16H34), n-octadecane (C18H38) and n-eicosane (C20H42) were studied. Differential scanning calorimetry was applied at the temperature range 248–348K to determine the melting/crystallization temperature, the heat of melting/crystallization and the specific heat of both the solid and liquid phases. Some results were compared with available literature data. The density of the n-alkanes at liquid state was also measured at different temperatures and their thermal diffusivity was estimated and compared to that obtained by the hot wire technique. The cumulative energy stored was estimated over a definite range of temperature for the three n-alkanes and this was found to be higher for eicosane.