Hydronic Heating Pavement with Low Temperature: The Effect of Pre-heating and Fluid Temperature on Anti-icing Performance

Abstract

A renewable method to mitigate the slippery condition on road surfaces is to use Hydronic Heating Pavement (HHP) system. The HHP system starts heating the road when the surface temperature is below both of the dew-point and the water freezing temperatures. Furthermore, in order to improve the anti-icing performance of the HHP system, it is necessary to pre-heat the road surface. The aims of this study are to evaluate the effects of: (i) pre-heating the road surface and (ii) varying the fluid temperature, when the road is pre-heated, on the anti-icing performance of the HHP system. The road surface was pre-heated by adding a temperature threshold (from 0 to 1.6 °C) to the freezing and dew-point temperatures. A two-dimensional numerical simulation model was developed using finite element method in order to calculate the annual required energy and remaining hours of the slippery conditions on the road surface. The numerical solver was validated by an analytical solution associated with an infinite region bounded internally by a pipe with a constant temperature. In order to evaluate the anti-icing performance of the HHP system, the climate data were selected from Östersund, an area in middle of Sweden with cold and long winter period. The results showed that running the HHP system by considering the temperature threshold of 0.1 °C for both freezing and dew-point temperatures led to approximately 110 h shorter slippery conditions on the road surface, compared to the conditions without pre-heating.