Heat transfer performance of paraffin wax based phase change materials applicable in building industry

Abstract

Thermal characterization of phase change materials (PCMs) compose of linear low-density polyethylene (LLDPE), paraffin wax (W) with a melting point of 25 °C, and expanded graphite (EG), that are highly effective in thermal energy storage systems in the building industry, is reported.

Thermal investigation of PCMs with various compositions of LLDPE, W and EG has been performed by nonconventional transient guarded hot plane technique (TGHPT) and compared with conventional differential scanning calorimetry (DSC) measurements. An excellent agreement in determination of thermal characteristics by both methods was found.

The highest values of the total amount of stored energy, sensible heat for solid and liquid states (Qtotal, Qs(solid) and Qs(liquid), respectively) were found for the PCMs with composition LLDPE/W/EG = 40/50/10 and 35/50/15 w/w/w.

Moreover, thermal conductivity and diffusivity of PCMs have been significantly improved by adding EG.

Additionally, life cycle assessment was performed to evaluate the environmental impact of three different materials as glass wool, rock wool and PCM used with brick wall.