Solar energy harvesting pavements on the road: comparative study and performance assessment

As a significant infrastructure in modern cities, road pavements occupy a great share of urban surfaces and absorb abundant solar radiation. Thus, pavements have tremendous potential in solar energy utilization and can serve as distributed energy generators in smart and sustainable cities. Some solar energy harvesting pavement modules have emerged in recent years, including pavement-integrated photovoltaic (PIPV) module, pavement-integrated solar thermal (PIST) module, and pavement-integrated photovoltaic thermal (PIPVT) module. In this study, for all the above modules, simulations were conducted with the developed and validated two-dimensional transient models on the weather conditions of four typical days in different seasons in Shanghai. Both the operating performance and influence on the urban heat island (UHI) effect were investigated to evaluate and compare their energy performance and effect on urban microclimatic conditions. The results show that the electricity yield of the PIPVT module is slightly higher than that of the PIPV module, while its heat yield is lower than that of the PIST module on all typical days. When considering both electricity and heat yields, the PIPVT module can achieve an average overall energy efficiency of 37.31%. Compared with the conventional pavement module, all three solar energy harvesting pavement modules have lower maximum asphalt average temperatures that can decelerate the thermal aging of asphalt concrete. The PIPVT module has the most significant effect on the reduction of the maximum asphalt average temperature, decreasing it by 10.57 degrees C on average. Additionally, all three solar energy harvesting pavement modules can mitigate the UHI effect, and the PIPVT and PIST modules have the most and the least influence on UHI effect mitigation, respectively.