Enhancement of solar regulation of phase change material window using vanadium dioxide for performance improvements

Reducing building energy consumption is one of the effective ways to achieve energy saving targets. Phase change material (PCM) windows have shown potential in reducing building energy consumption by absorbing and releasing latent heat. However, their high solar transmittance at high temperatures significantly increases cooling loads, thereby limiting their energy-saving potentials. To this end, this study employs vanadium dioxide (VO 2 ), a solar spectrally selective material, to enhance the solar regulation of the PCM window. A facile spinning coating method is adopted to fabricate the composite window coupling VO 2 and PCM. Results indicate that the composite window shows excellent solar modulation capabilities at high temperature while exerts little impacts on the original solar property of PCM window at low temperature. Outdoor tests show that at high temperature, the composite window can reduce indoor temperature up to 13.9 °C, while having negligible effects on indoor temperature during low-temperature periods in comparison with PCM window. Numerical simulation further illustrates that the composite window can achieve >22.2 % energy savings compared with PCM window. This study provides solution of effective solar regulation of PCM window for improving building energy efficiency . • Vanadium dioxide was used to enhance the solar modulation of phase change material windows. • Composite windows can reduce indoor temperature by 13.9 °C under high temperature conditions. • Compared to PCM windows, composite windows can achieve energy savings of >22.2 %.