Thermal energy storage plays an important role in heat management because of the demand for developed energy
conservation, and has applications in diverse areas, from buildings to textiles and clothings. In this study, we aimed to
improve thermal characteristics of polyurethane rigid foams that have been widely used for thermal insulation in
electrical water heaters. Through this work, paraffin waxes with melting point of 55~65°C act as phase change materials.
Then the phase change materials were incorporated into the polyurethane foams at certain ratio. The polyurethane/phase
change composite materials used as insulation layers in electrical water heaters performed the enthalpy value of 5~15 J/g.
Energy efficiency of the electrical water heaters was tested according to the National Standard of China GB 21519-2008.
Results show that 24 h energy consumption of the electrical water heaters manufactured by traditional polyurethane rigid
foams and polyurethane/phase change material composites was 1.0612 kWh and 0.9833 kWh, respectively. The results
further show that the energy-saving rate is 7.36%. These proved that polyurethane/phase change composite materials can
be designed as thermal insulators equipped with electrical water heaters and have a significant effect on energy