Reduction of Urban Heat Island Effect through Harvest of Heat Energy from Asphalt Pavements

Asphalt pavement surfaces contribute significantly to the urban heat island effect. Their relatively high temperature, caused by absorption of solar energy, results in emission of heat to the surrounding air, leading to a rise in its temperature, deterioration of its quality, and an increase in energy consumption of the surrounding buildings. The proposed concept is that the heat from the pavement can be removed by flowing an appropriate fluid in a piping system combined with high conductivity layers, and this would lead to a reduction of temperature in the pavement, and lowering of heat emitted from the surface to the surrounding air. The concept, results of laboratory experiments and finite element modeling/simulation are presented. Comparison of results from the application of the proposed concept with those from changing the albedo of existing pavements is made. The conclusions are that a significant lowering of surface temperature and emitted radiation is possible, and the reduction in temperature is affected by the conductivity of the mix, the type of paint/layer on the surface, the heat-exchanger system, and the temperature of the fluid. The results could be used to engineer a system with optimum piping location and spacing, and properties of the fluid to achieve the desirable result.