Effect of PCM cool roof system on the reduction in urban heat island phenomenon

The urban heat island (UHI) phenomenon incurs various problems for human health as fine dust and hazardous pollutants are not ventilated well in urban areas. For example, downtown areas had a higher temperature than that of suburban regions. The purpose of the present study is to derive the reduction effect on the UHI phenomenon by applying phase-change material (PCM) to building roofs as a foundational study to reduce the UHI phenomenon. In the present study, an effect of reduction in surface temperature was verified through mock-up performance test on a PCM cool roof system manufactured by combining a PCM and radiation hardened wood (wood-plastic composite), and analysis on temperature distribution simulation was conducted by utilizing the mock-up test results to verify the temperature reduction in the canopy layer and roof surface. The study result showed that a temperature was decreased by 6.8 °C on average when the PCM cool roof system was applied. The result of the temperature distribution simulation based on the above experimental data verified that a temperature in the urban canopy layer in the commercial zone was reduced by 7.8 °C in summer and 11.3 °C in winter, and that in the residential zone was decreased by 6.4 °C in summer and 10.5 °C in winter, respectively.