Hydronic Road-Heating Systems: Environmental Performance and the Case of Ingolstadt Ramps

Snowfall and ice formation on road surface significantly impact the safety of driving conditions. To resolve this, every year salt and de-icing chemicals are sprinkled on roads. However, use of salts and snow ploughing have environmental as well as economical disadvantages. To resolve these problems, hydronic road heating systems are valid alternatives. Heat transfer fluid, i.e. mixture of ethanol and water, is pumped into a tubular circulation system under the asphalt. By this technology, the road and pavements shall stay ice-free even in times of snowfall and temperatures below the freezing point. The system can also be used to cool the asphalt in case of extreme heat, which - besides the heating effect - could also prevent road from damages in extreme summers. This study aims to compare the environmental impact of use of salts and road-heating system in terms of GHG emissions. To assess the environmental impact, an operational road heating system for a ramp in Ingolstadt, Germany, is considered. A cradle-to-grave analysis technique is used to determine the environmental effects based on a life-cycle assessment (LCA) framework. The analysis includes nine components solemnly responsible for hydronic heating of asphalt surface such as local heating pipe, insulation, pumps, and heat meters. Comparison is performed in terms of relative and total impact over 50-year lifetime of three heated ramps having 1989 m(2) surface area in total. The results show that the asphalt and heating-circuit causes the major fraction (65 %) of overall GHG emissions, with total life-time emissions of 28.10 kg CO2 eq./m(2) of heated surface. During an operational life of 50 years, road heating systems emit 18 %less CO2 eq./m(2) as compared to the use of salts.

Automated summary

Snowfall and ice formation on road surface can be a safety hazard for driving, and the traditional methods of using salt and de-icing chemicals have environmental and economic disadvantages. Hydronic road heating systems, which circulate a mixture of ethanol and water under the asphalt, provide a valid alternative. This study compares the environmental impact of using salts versus using a road heating system, and the results show that the heating system emits less CO2 over its lifetime.